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Sample records for high altitude ice

  1. Possible Mechanisms for Turbofan Engine Ice Crystal Icing at High Altitude

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    Tsao, Jen-Ching; Struk, Peter M.; Oliver, Michael J.

    2016-01-01

    A thermodynamic model is presented to describe possible mechanisms of ice formation on unheated surfaces inside a turbofan engine compression system from fully glaciated ice crystal clouds often formed at high altitude near deep convective weather systems. It is shown from the analysis that generally there could be two distinct types of ice formation: (1) when the "surface freezing fraction" is in the range of 0 to 1, dominated by the freezing of water melt from fully or partially melted ice crystals, the ice structure is formed from accretion with strong adhesion to the surface, and (2) when the "surface melting fraction" is the range of 0 to 1, dominated by the further melting of ice crystals, the ice structure is formed from accumulation of un-melted ice crystals with relatively weak bonding to the surface. The model captures important qualitative trends of the fundamental ice-crystal icing phenomenon reported earlier (Refs. 1 and 2) from the research collaboration work by NASA and the National Research Council (NRC) of Canada. Further, preliminary analysis of test data from the 2013 full scale turbofan engine ice crystal icing test (Ref. 3) conducted in the NASA Glenn Propulsion Systems Laboratory (PSL) has also suggested that (1) both types of ice formation occurred during the test, and (2) the model has captured some important qualitative trend of turning on (or off) the ice crystal ice formation process in the tested engine low pressure compressor (LPC) targeted area under different icing conditions that ultimately would lead to (or suppress) an engine core roll back (RB) event.

  2. Preliminary Results From a Heavily Instrumented Engine Ice Crystal Icing Test in a Ground Based Altitude Test Facility

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    Flegel, Ashlie B.; Oliver, Michael J.

    2016-01-01

    Preliminary results from the heavily instrumented ALF502R-5 engine test conducted in the NASA Glenn Research Center Propulsion Systems Laboratory are discussed. The effects of ice crystal icing on a full scale engine is examined and documented. This same model engine, serial number LF01, was used during the inaugural icing test in the Propulsion Systems Laboratory facility. The uncommanded reduction of thrust (rollback) events experienced by this engine in flight were simulated in the facility. Limited instrumentation was used to detect icing on the LF01 engine. Metal temperatures on the exit guide vanes and outer shroud and the load measurement were the only indicators of ice formation. The current study features a similar engine, serial number LF11, which is instrumented to characterize the cloud entering the engine, detect/characterize ice accretion, and visualize the ice accretion in the region of interest. Data were acquired at key LF01 test points and additional points that explored: icing threshold regions, low altitude, high altitude, spinner heat effects, and the influence of varying the facility and engine parameters. For each condition of interest, data were obtained from some selected variations of ice particle median volumetric diameter, total water content, fan speed, and ambient temperature. For several cases the NASA in-house engine icing risk assessment code was used to find conditions that would lead to a rollback event. This study further helped NASA develop necessary icing diagnostic instrumentation, expand the capabilities of the Propulsion Systems Laboratory, and generate a dataset that will be used to develop and validate in-house icing prediction and risk mitigation computational tools. The ice accretion on the outer shroud region was acquired by internal video cameras. The heavily instrumented engine showed good repeatability of icing responses when compared to the key LF01 test points and during day-to-day operation. Other noticeable

  3. Predicting abundance and variability of ice nucleating particles in precipitation at the high-altitude observatory Jungfraujoch

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    E. Stopelli

    2016-07-01

    Full Text Available Nucleation of ice affects the properties of clouds and the formation of precipitation. Quantitative data on how ice nucleating particles (INPs determine the distribution, occurrence and intensity of precipitation are still scarce. INPs active at −8 °C (INPs−8 were observed for 2 years in precipitation samples at the High-Altitude Research Station Jungfraujoch (Switzerland at 3580 m a.s.l. Several environmental parameters were scanned for their capability to predict the observed abundance and variability of INPs−8. Those singularly presenting the best correlations with observed number of INPs−8 (residual fraction of water vapour, wind speed, air temperature, number of particles with diameter larger than 0.5 µm, season, and source region of particles were implemented as potential predictor variables in statistical multiple linear regression models. These models were calibrated with 84 precipitation samples collected during the first year of observations; their predictive power was successively validated on the set of 15 precipitation samples collected during the second year. The model performing best in calibration and validation explains more than 75 % of the whole variability of INPs−8 in precipitation and indicates that a high abundance of INPs−8 is to be expected whenever high wind speed coincides with air masses having experienced little or no precipitation prior to sampling. Such conditions occur during frontal passages, often accompanied by precipitation. Therefore, the circumstances when INPs−8 could be sufficiently abundant to initiate the ice phase in clouds may frequently coincide with meteorological conditions favourable to the onset of precipitation events.

  4. Variability of IN measured with the Fast Ice Nucleus Chamber (FINCH) at the high altitude research station Jungfraujoch during wintertime 2013

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    Frank, Fabian; Nillius, Björn; Bundke, Ulrich; Curtius, Joachim

    2014-05-01

    Ice nuclei (IN) are an important component of the atmospheric aerosol. Despite their low concentrations in the atmosphere, they have an influence on the formation of ice crystals in mixed-phase clouds and therefore on precipitation. The Fast Ice Nucleus CHamber (FINCH)1, a counter for ice nucleating particles developed at the Goethe University Frankfurt am Main allows long-term measurements of the IN number concentration. In FINCH the ice activation of the aerosol particles is achieved by mixing air flows with different temperature and humidity. The IN number concentration measurements at different meteorological conditions during the INUIT-JFJ campaign at the high altitude research station Jungfraujoch in Switzerland are presented and its variability are discussed. The good operational performance of the instrument allowed up to 10 hours of continuous measurements. Acknowledgment: This work was supported by the German Research Foundation, DFG Grant: BU 1432/3-2 BU 1432/4-1 in the framework of INUIT (FOR 1525) and SPP 1294 HALO. 1- Bundke, U., Nillius, B., Jaenicke, R., Wetter, T., Klein, H., and Bingemer, H. (2008). The fast ice nucleus chamber finch. Atmospheric Research, 90:180-186.

  5. Modeling Commercial Turbofan Engine Icing Risk With Ice Crystal Ingestion

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    Jorgenson, Philip C. E.; Veres, Joseph P.

    2013-01-01

    The occurrence of ice accretion within commercial high bypass aircraft turbine engines has been reported under certain atmospheric conditions. Engine anomalies have taken place at high altitudes that have been attributed to ice crystal ingestion, partially melting, and ice accretion on the compression system components. The result was degraded engine performance, and one or more of the following: loss of thrust control (roll back), compressor surge or stall, and flameout of the combustor. As ice crystals are ingested into the fan and low pressure compression system, the increase in air temperature causes a portion of the ice crystals to melt. It is hypothesized that this allows the ice-water mixture to cover the metal surfaces of the compressor stationary components which leads to ice accretion through evaporative cooling. Ice accretion causes a blockage which subsequently results in the deterioration in performance of the compressor and engine. The focus of this research is to apply an engine icing computational tool to simulate the flow through a turbofan engine and assess the risk of ice accretion. The tool is comprised of an engine system thermodynamic cycle code, a compressor flow analysis code, and an ice particle melt code that has the capability of determining the rate of sublimation, melting, and evaporation through the compressor flow path, without modeling the actual ice accretion. A commercial turbofan engine which has previously experienced icing events during operation in a high altitude ice crystal environment has been tested in the Propulsion Systems Laboratory (PSL) altitude test facility at NASA Glenn Research Center. The PSL has the capability to produce a continuous ice cloud which are ingested by the engine during operation over a range of altitude conditions. The PSL test results confirmed that there was ice accretion in the engine due to ice crystal ingestion, at the same simulated altitude operating conditions as experienced previously in

  6. HIGH-ALTITUDE ILLNESS

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    Dwitya Elvira

    2015-05-01

    Full Text Available AbstrakHigh-altitude illness (HAI merupakan sekumpulan gejala paru dan otak yang terjadi pada orang yang baru pertama kali mendaki ke ketinggian. HAI terdiri dari acute mountain sickness (AMS, high-altitude cerebral edema (HACE dan high-altitude pulmonary edema (HAPE. Tujuan tinjauan pustaka ini adalah agar dokter dan wisatawan memahami risiko, tanda, gejala, dan pengobatan high-altitude illness. Perhatian banyak diberikan terhadap penyakit ini seiring dengan meningkatnya popularitas olahraga ekstrim (mendaki gunung tinggi, ski dan snowboarding dan adanya kemudahan serta ketersediaan perjalanan sehingga jutaan orang dapat terpapar bahaya HAI. Di Pherice, Nepal (ketinggian 4343 m, 43% pendaki mengalami gejala AMS. Pada studi yang dilakukan pada tempat wisata di resort ski Colorado, Honigman menggambarkan kejadian AMS 22% pada ketinggian 1850 m sampai 2750 m, sementara Dean menunjukkan 42% memiliki gejala pada ketinggian 3000 m. Aklimatisasi merupakan salah satu tindakan pencegahan yang dapat dilakukan sebelum pendakian, selain beberapa pengobatan seperti asetazolamid, dexamethasone, phosopodiestrase inhibitor, dan ginko biloba.Kata kunci: high-altitude illness, acute mountain sickness, edema cerebral, pulmonary edema AbstractHigh-altitude illness (HAI is symptoms of lung and brain that occurs in people who first climb to altitude. HAI includes acute mountain sickness (AMS, high-altitude cerebral edema (HACE and high altitude pulmonary edema (HAPE. The objective of this review was to understand the risks, signs, symptoms, and treatment of high-altitude illness. The attention was given to this disease due to the rising popularity of extreme sports (high mountain climbing, skiing and snowboarding and the ease and availability of the current travelling, almost each year, millions of people could be exposed to the danger of HAI. In Pherice, Nepal (altitude 4343 m, 43% of climbers have symptoms of AMS. Furthermore, in a study conducted at sites in

  7. Athletes at High Altitude.

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    Khodaee, Morteza; Grothe, Heather L; Seyfert, Jonathan H; VanBaak, Karin

    2016-01-01

    Athletes at different skill levels perform strenuous physical activity at high altitude for a variety of reasons. Multiple team and endurance events are held at high altitude and may place athletes at increased risk for developing acute high altitude illness (AHAI). Training at high altitude has been a routine part of preparation for some of the high level athletes for a long time. There is a general belief that altitude training improves athletic performance for competitive and recreational athletes. A review of relevant publications between 1980 and 2015 was completed using PubMed and Google Scholar. Clinical review. Level 3. AHAI is a relatively uncommon and potentially serious condition among travelers to altitudes above 2500 m. The broad term AHAI includes several syndromes such as acute mountain sickness (AMS), high altitude pulmonary edema (HAPE), and high altitude cerebral edema (HACE). Athletes may be at higher risk for developing AHAI due to faster ascent and more vigorous exertion compared with nonathletes. Evidence regarding the effects of altitude training on athletic performance is weak. The natural live high, train low altitude training strategy may provide the best protocol for enhancing endurance performance in elite and subelite athletes. High altitude sports are generally safe for recreational athletes, but they should be aware of their individual risks. Individualized and appropriate acclimatization is an essential component of injury and illness prevention.

  8. High altitude illness

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    Hartman-Ksycińska, Anna; Kluz-Zawadzka, Jolanta; Lewandowski, Bogumił

    High-altitude illness is a result of prolonged high-altitude exposure of unacclimatized individuals. The illness is seen in the form of acute mountain sickness (AMS) which if not treated leads to potentially life-threatening high altitude pulmonary oedema and high-altitude cerebral oedema. Medical problems are caused by hypobaric hypoxia stimulating hypoxia-inducible factor (HIF) release. As a result, the central nervous system, circulation and respiratory system function impairment occurs. The most important factor in AMS treatment is acclimatization, withdrawing further ascent and rest or beginning to descent; oxygen supplementation, and pharmacological intervention, and, if available, a portable hyperbaric chamber. Because of the popularity of high-mountain sports and tourism better education of the population at risk is essential.

  9. Brain Food at High Altitude.

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    Jain, Vishal

    2016-01-01

    Scenic view at high altitude is a pleasure to the eyes, but it has some shortcoming effects as well. High altitude can be divided into different categories, i.e., high altitude (3000-5000 ft), very high altitude (5000-8000 ft), and extreme altitude (above 8000 ft). Much of the population resides at high altitude, and others go there for tourism. Military personnel are also posted there to defend boundaries. As we ascent to high altitude, partial pressure of oxygen reduces, whereas concentration remains the same; this reduces the availability of oxygen to different body parts. This pathophysiological condition is known as hypobaric hypoxia (HH) which leads to oxidative stress and further causes cognitive dysfunction in some cases. Hypoxia causes neurodegeneration in different brain regions; however, the hippocampus is found to be more prone in comparison to other brain regions. As the hippocampus is affected most, therefore, spatial memory is impaired most during such condition. This chapter will give a brief review of the damaging effect of high altitude on cognition and also throw light on possible herbal interventions at high altitude, which can improve cognitive performance as well as provide protection against the deteriorating effect of hypobaric hypoxia at high altitude.

  10. Altitude training considerations for the winter sport athlete.

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    Chapman, Robert F; Stickford, Jonathon L; Levine, Benjamin D

    2010-03-01

    Winter sports events routinely take place at low to moderate altitudes, and nearly all Winter Olympic Games have had at least one venue at an altitude >1000 m. The acute and chronic effects of altitude can have a substantial effect on performance outcomes. Acutely, the decline in oxygen delivery to working muscle decreases maximal oxygen uptake, negatively affecting performance in endurance events, such as cross-country skiing and biathlon. The reduction in air resistance at altitude can dramatically affect sports involving high velocities and technical skill components, such as ski jumping, speed skating, figure skating and ice hockey. Dissociation between velocity and sensations usually associated with work intensity (ventilation, metabolic signals in skeletal muscle and heart rate) may impair pacing strategy and make it difficult to determine optimal race pace. For competitions taking place at altitude, a number of strategies may be useful, depending on the altitude of residence of the athlete and ultimate competition altitude, as follows. First, allow extra time and practice (how much is yet undetermined) for athletes to adjust to the changes in projectile motion; hockey, shooting, figure skating and ski jumping may be particularly affected. These considerations apply equally in the reverse direction; that is, for athletes practising at altitude but competing at sea level. Second, allow time for acclimatization for endurance sports: 3-5 days if possible, especially for low altitude (500-2000 m); 1-2 weeks for moderate altitude (2000-3000 m); and at least 2 weeks if possible for high altitude (>3000 m). Third, increase exercise-recovery ratios as much as possible, with 1:3 ratio probably optimal, and consider more frequent substitutions for sports where this is allowed, such as ice hockey. Fourth, consider the use of supplemental O(2) on the sideline (ice hockey) or in between heats (skating and Alpine skiing) to facilitate recovery. For competitions at sea

  11. Ice nuclei measurements at a high altitude remote station in the Northern Apennines

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    Schrod, Jann; Bingemer, Heinz; Haunold, Werner; Curtius, Joachim; Decesari, Stefano; Marinoni, Angela; Rinaldi, Matteo; Bonasoni, Paolo; Cristofanelli, Paolo

    2013-04-01

    an optical particle sizer. A clear increase of submicron particles was noted during the passage of the dust plume. The heavily dust loaded air had high IN concentrations up to 270 IN/l . The maximum fraction of large aerosol particles activated as ice nuclei during this dust event was one ice nucleus in 1250 aerosol particles. Acknowledgements: This work was funded by Deutsche Forschungsgemeinschaft (DFG) under the Research Unit INUIT. References [Klein et al. 2010] Klein, H. ; Haunold, W. ; Bundke, U. ; Nillius, B. ; Wetter, T. ; Schallenberg, S. ; Bingemer, H.: A new method for sampling of atmospheric ice nuclei with subsequent analysis in a static diffusion chamber. In: Atmospheric Research 96 (2010), p. 218 - 224.

  12. High Altitude and Heart

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    Murat Yalcin

    2011-04-01

    Full Text Available Nowadays, situations associated with high altitude such as mountaineering, aviation increasingly draw the attention of people. Gas pressure decreases and hypoxia is encountered when climbing higher. Physiological and pathological responses of human body to different heights are different. Therefore, physiological and pathological changes that may occur together with height and to know the clinical outcomes of these are important . Acute mountain sickness caused by high altitude and high altitude cerebral edema are preventable diseases with appropriate precautions. Atmospheric oxygen decreasing with height, initiates many adaptive mechanisms. These adaptation mechanisms and acclimatization vary widely among individuals because of reasons such as environmental factors, exercise and cold. High altitude causes different changes in the cardiovascular system with various mechanisms. Although normal individuals easily adapt to these changes, this situation can lead to undesirable results in people with heart disease. For this reason, it should be known the effective evaluation of the people with known heart disease before traveling to high altitude and the complications due to the changes with height and the recommendations can be made to these patients. [TAF Prev Med Bull 2011; 10(2.000: 211-222

  13. High-altitude pulmonary hypertension

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    X-Q. Xu

    2009-03-01

    Full Text Available High-altitude pulmonary hypertension (HAPH is a specific disease affecting populations that live at high elevations. The prevalence of HAPH among those residing at high altitudes needs to be further defined. Whereas reduction in nitric oxide production may be one mechanism for the development of HAPH, the roles of endothelin-1 and prostaglandin I2 pathways in the pathogenesis of HAPH deserve further study. Although some studies have suggested that genetic factors contribute to the pathogenesis of HAPH, data published to date are insufficient for the identification of a significant number of gene polymorphims in HAPH. The clinical presentation of HAPH is nonspecific. Exertional dyspnoea is the most common symptom and signs related to right heart failure are common in late stages of HAPH. Echocardiography is the most useful screening tool and right heart catheterisation is the gold standard for the diagnosis of HAPH. The ideal management for HAPH is migration to lower altitudes. Phosphodiesterase 5 is an attractive drug target for the treatment of HAPH. In addition, acetazolamide is a promising therapeutic agent for high-altitude pulmonary hypertension. To date, no evidence has confirmed whether endothelin-receptor antagonists have efficacy in the treatment of high-altitude pulmonary hypertension.

  14. Mass balance, meteorology, area altitude distribution, glacier-surface altitude, ice motion, terminus position, and runoff at Gulkana Glacier, Alaska, 1996 balance year

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    March, Rod S.

    2003-01-01

    The 1996 measured winter snow, maximum winter snow, net, and annual balances in the Gulkana Glacier Basin were evaluated on the basis of meteorological, hydrological, and glaciological data. Averaged over the glacier, the measured winter snow balance was 0.87 meter on April 18, 1996, 1.1 standard deviation below the long-term average; the maximum winter snow balance, 1.06 meters, was reached on May 28, 1996; and the net balance (from August 30, 1995, to August 24, 1996) was -0.53 meter, 0.53 standard deviation below the long-term average. The annual balance (October 1, 1995, to September 30, 1996) was -0.37 meter. Area-averaged balances were reported using both the 1967 and 1993 area altitude distributions (the numbers previously given in this abstract use the 1993 area altitude distribution). Net balance was about 25 percent less negative using the 1993 area altitude distribution than the 1967 distribution. Annual average air temperature was 0.9 degree Celsius warmer than that recorded with the analog sensor used since 1966. Total precipitation catch for the year was 0.78 meter, 0.8 standard deviations below normal. The annual average wind speed was 3.5 meters per second in the first year of measuring wind speed. Annual runoff averaged 1.50 meters over the basin, 1.0 standard deviation below the long-term average. Glacier-surface altitude and ice-motion changes measured at three index sites document seasonal ice-speed and glacier-thickness changes. Both showed a continuation of a slowing and thinning trend present in the 1990s. The glacier terminus and lower ablation area were defined for 1996 with a handheld Global Positioning System survey of 126 locations spread out over about 4 kilometers on the lower glacier margin. From 1949 to 1996, the terminus retreated about 1,650 meters for an average retreat rate of 35 meters per year.

  15. Acute high-altitude sickness

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    Andrew M. Luks

    2017-02-01

    Full Text Available At any point 1–5 days following ascent to altitudes ≥2500 m, individuals are at risk of developing one of three forms of acute altitude illness: acute mountain sickness, a syndrome of nonspecific symptoms including headache, lassitude, dizziness and nausea; high-altitude cerebral oedema, a potentially fatal illness characterised by ataxia, decreased consciousness and characteristic changes on magnetic resonance imaging; and high-altitude pulmonary oedema, a noncardiogenic form of pulmonary oedema resulting from excessive hypoxic pulmonary vasoconstriction which can be fatal if not recognised and treated promptly. This review provides detailed information about each of these important clinical entities. After reviewing the clinical features, epidemiology and current understanding of the pathophysiology of each disorder, we describe the current pharmacological and nonpharmacological approaches to the prevention and treatment of these diseases.

  16. Diagnostic criteria of high-altitude de-adaptation for high-altitude migrants returning to the plains: a multicenter, randomized controlled trial

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    Qi-quan ZHOU

    2012-02-01

    Full Text Available Objective  To investigate the diagnostic method of high-altitude de-adaptation and constitute the diagnostic criteria of high-altitude de-adaptation for people returning to the plains from high-altitude. Methods  Epidemiological survey and clinical multicenter randomized controlled studies were used to determine/perform blood picture, routine urine analysis, routine stool examination, myocardial enzymes, liver and kidney functions, nerve function, sex hormone, microalbuminuria, ECG, echocardiography, pulmonary function tests, and so on, in 3011 subjects after they returned to the plains from high-altitude. The diagnostic criteria of high-altitude de-adaptation were formulated by a comparative analysis of the obtained data with those of healthy subjects living in the same area, altitude, and age. The regularity and characteristics of high-altitude de-adaptation syndrome were found and diagnostic criteria for high-altitude de-adaptation was established based on the results. Results  The investigative results showed that the incidence of high-altitude de-adaptation syndrome was found in 84.36% of population returning to the plains from high-altitude. About 60% of them were considered to have mild reactions, 30% medium, and only 10% were severe. The lower the altitude they returned to, the longer the duration of stay in highland, and the heavier the labor they engaged in high altitude, the higher the incidence rate of high-altitude de-adaptation syndrome was. Patients with high-altitude de-adaptation syndrome exhibited hematological abnormality and abnormal ventricular function, especially the right ventricular diastolic function after returning for 1 year to 5 years. Long-term hypoxia exposure often caused obvious change in cardiac morphology with left and right ventricular hypertrophy, particularly the right ventricle. In addition, low blood pressure and low pulse pressure were found at times. Microalbuminuria was found in some high-altitude de

  17. The Horizontal Ice Nucleation Chamber (HINC): INP measurements at conditions relevant for mixed-phase clouds at the High Altitude Research Station Jungfraujoch

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    Lacher, Larissa; Lohmann, Ulrike; Boose, Yvonne; Zipori, Assaf; Herrmann, Erik; Bukowiecki, Nicolas; Steinbacher, Martin; Kanji, Zamin A.

    2017-12-01

    In this work we describe the Horizontal Ice Nucleation Chamber (HINC) as a new instrument to measure ambient ice-nucleating particle (INP) concentrations for conditions relevant to mixed-phase clouds. Laboratory verification and validation experiments confirm the accuracy of the thermodynamic conditions of temperature (T) and relative humidity (RH) in HINC with uncertainties in T of ±0.4 K and in RH with respect to water (RHw) of ±1.5 %, which translates into an uncertainty in RH with respect to ice (RHi) of ±3.0 % at T > 235 K. For further validation of HINC as a field instrument, two measurement campaigns were conducted in winters 2015 and 2016 at the High Altitude Research Station Jungfraujoch (JFJ; Switzerland, 3580 m a. s. l. ) to sample ambient INPs. During winters 2015 and 2016 the site encountered free-tropospheric conditions 92 and 79 % of the time, respectively. We measured INP concentrations at 242 K at water-subsaturated conditions (RHw = 94 %), relevant for the formation of ice clouds, and in the water-supersaturated regime (RHw = 104 %) to represent ice formation occurring under mixed-phase cloud conditions. In winters 2015 and 2016 the median INP concentrations at RHw = 94 % was below the minimum detectable concentration. At RHw = 104 %, INP concentrations were an order of magnitude higher, with median concentrations in winter 2015 of 2.8 per standard liter (std L-1; normalized to standard T of 273 K and pressure, p, of 1013 hPa) and 4.7 std L-1 in winter 2016. The measurements are in agreement with previous winter measurements obtained with the Portable Ice Nucleation Chamber (PINC) of 2.2 std L-1 at the same location. During winter 2015, two events caused the INP concentrations at RHw = 104 % to significantly increase above the campaign average. First, an increase to 72.1 std L-1 was measured during an event influenced by marine air, arriving at the JFJ from the North Sea and the Norwegian Sea. The contribution from anthropogenic or other

  18. Analysis of high-altitude de-acclimatization syndrome after exposure to high altitudes: a cluster-randomized controlled trial.

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    He, Binfeng; Wang, Jianchun; Qian, Guisheng; Hu, Mingdong; Qu, Xinming; Wei, Zhenghua; Li, Jin; Chen, Yan; Chen, Huaping; Zhou, Qiquan; Wang, Guansong

    2013-01-01

    The syndrome of high-altitude de-acclimatization commonly takes place after long-term exposure to high altitudes upon return to low altitudes. The syndrome severely affects the returnee's quality of life. However, little attention has been paid to careful characterization of the syndrome and their underlying mechanisms. Male subjects from Chongqing (n = 67, 180 m) and Kunming (n = 70, 1800 m) visited a high-altitude area (3650 m) about 6 months and then returned to low-altitude. After they came back, all subjects were evaluated for high-altitude de-acclimatization syndrome on the 3(rd), 50(th), and 100(th). Symptom scores, routine blood and blood gas tests, and myocardial zymograms assay were used for observation their syndrome. The results showed that the incidence and severity of symptoms had decreased markedly on the 50(th) and 100(th) days, compared with the 3(rd) day. The symptom scores and incidence of different symptoms were lower among subjects returning to Kunming than among those returning to Chongqing. On the 3(rd) day, RBC, Hb, Hct, CK, CK-MB, and LDH values were significantly lower than values recorded at high altitudes, but they were higher than baseline values. On the 50(th) day, these values were not different from baseline values, but LDH levels did not return to baseline until the 100(th) day. These data show that, subjects who suffered high-altitude de-acclimatization syndrome, the recovery fully processes takes a long time (≥ 100(th) days). The appearance of the syndrome is found to be related to the changes in RBC, Hb, Hct, CK, CK-MB, and LDH levels, which should be caused by reoxygenation after hypoxia.

  19. Assessing water resources under climate change in high-altitude catchments: a methodology and an application in the Italian Alps

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    Aili, T.; Soncini, A.; Bianchi, A.; Diolaiuti, G.; D'Agata, C.; Bocchiola, D.

    2018-01-01

    Assessment of the future water resources in the Italian Alps under climate change is required, but the hydrological cycle of the high-altitude catchments therein is poorly studied and little understood. Hydrological monitoring and modeling in the Alps is difficult, given the lack of first hand, site specific data. Here, we present a method to model the hydrological cycle of poorly monitored high-altitude catchments in the Alps, and to project forward water resources availability under climate change. Our method builds on extensive experience recently and includes (i) gathering data of climate, of cryospheric variables, and of hydrological fluxes sparsely available; (ii) robust physically based glacio-hydrological modeling; and (iii) using glacio-hydrological projections from GCM models. We apply the method in the Mallero River, in the central (Retiche) Alps of Italy. The Mallero river covers 321 km2, with altitude between 310 and 4015 m a.s.l., and it has 27 km2 of ice cover. The glaciers included in the catchment underwent large mass loss recently, thus Mallero is largely paradigmatic of the present situation of Alpine rivers. We set up a spatially explicit glacio-hydrological model, describing the cryospheric evolution and the hydrology of the area during a control run CR, from 1981 to 2007. We then gather climate projections until 2100 from three Global Climate Models of the IPCC AR5 under RCP2.6, RCP4.5, and RCP8.5. We project forward flow statistics, flow components (rainfall, snow melt, ice melt), ice cover, and volume for two reference decades, namely 2045-2054 and 2090-2099. We foresee reduction of the ice bodies from - 62 to - 98% in volume (year 2100 vs year 1981), and subsequent large reduction of ice melt contribution to stream flows (from - 61 to - 88%, 2100 vs CR). Snow melt, now covering 47% of the stream flows yearly, would also be largely reduced (from - 19 to - 56%, 2100 vs CR). The stream flows will decrease on average at 2100 (from + 1 to - 25

  20. Shilajit: A panacea for high-altitude problems.

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    Meena, Harsahay; Pandey, H K; Arya, M C; Ahmed, Zakwan

    2010-01-01

    High altitude problems like hypoxia, acute mountain sickness, high altitude cerebral edema, pulmonary edema, insomnia, tiredness, lethargy, lack of appetite, body pain, dementia, and depression may occur when a person or a soldier residing in a lower altitude ascends to high-altitude areas. These problems arise due to low atmospheric pressure, severe cold, high intensity of solar radiation, high wind velocity, and very high fluctuation of day and night temperatures in these regions. These problems may escalate rapidly and may sometimes become life-threatening. Shilajit is a herbomineral drug which is pale-brown to blackish-brown, is composed of a gummy exudate that oozes from the rocks of the Himalayas in the summer months. It contains humus, organic plant materials, and fulvic acid as the main carrier molecules. It actively takes part in the transportation of nutrients into deep tissues and helps to overcome tiredness, lethargy, and chronic fatigue. Shilajit improves the ability to handle high altitudinal stresses and stimulates the immune system. Thus, Shilajit can be given as a supplement to people ascending to high-altitude areas so that it can act as a "health rejuvenator" and help to overcome high-altitude related problems.

  1. Modeling of Commercial Turbofan Engine With Ice Crystal Ingestion: Follow-On

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    Jorgenson, Philip C. E.; Veres, Joseph P.; Coennen, Ryan

    2014-01-01

    The occurrence of ice accretion within commercial high bypass aircraft turbine engines has been reported under certain atmospheric conditions. Engine anomalies have taken place at high altitudes that have been attributed to ice crystal ingestion, partially melting, and ice accretion on the compression system components. The result was degraded engine performance, and one or more of the following: loss of thrust control (roll back), compressor surge or stall, and flameout of the combustor. As ice crystals are ingested into the fan and low pressure compression system, the increase in air temperature causes a portion of the ice crystals to melt. It is hypothesized that this allows the ice-water mixture to cover the metal surfaces of the compressor stationary components which leads to ice accretion through evaporative cooling. Ice accretion causes a blockage which subsequently results in the deterioration in performance of the compressor and engine. The focus of this research is to apply an engine icing computational tool to simulate the flow through a turbofan engine and assess the risk of ice accretion. The tool is comprised of an engine system thermodynamic cycle code, a compressor flow analysis code, and an ice particle melt code that has the capability of determining the rate of sublimation, melting, and evaporation through the compressor flow path, without modeling the actual ice accretion. A commercial turbofan engine which has previously experienced icing events during operation in a high altitude ice crystal environment has been tested in the Propulsion Systems Laboratory (PSL) altitude test facility at NASA Glenn Research Center. The PSL has the capability to produce a continuous ice cloud which is ingested by the engine during operation over a range of altitude conditions. The PSL test results confirmed that there was ice accretion in the engine due to ice crystal ingestion, at the same simulated altitude operating conditions as experienced previously in

  2. Modeling of Commercial Turbofan Engine with Ice Crystal Ingestion; Follow-On

    Science.gov (United States)

    Jorgenson, Philip C. E.; Veres, Joseph P.; Coennen, Ryan

    2014-01-01

    The occurrence of ice accretion within commercial high bypass aircraft turbine engines has been reported under certain atmospheric conditions. Engine anomalies have taken place at high altitudes that have been attributed to ice crystal ingestion, partially melting, and ice accretion on the compression system components. The result was degraded engine performance, and one or more of the following: loss of thrust control (roll back), compressor surge or stall, and flameout of the combustor. As ice crystals are ingested into the fan and low pressure compression system, the increase in air temperature causes a portion of the ice crystals to melt. It is hypothesized that this allows the ice-water mixture to cover the metal surfaces of the compressor stationary components which leads to ice accretion through evaporative cooling. Ice accretion causes a blockage which subsequently results in the deterioration in performance of the compressor and engine. The focus of this research is to apply an engine icing computational tool to simulate the flow through a turbofan engine and assess the risk of ice accretion. The tool is comprised of an engine system thermodynamic cycle code, a compressor flow analysis code, and an ice particle melt code that has the capability of determining the rate of sublimation, melting, and evaporation through the compressor flow path, without modeling the actual ice accretion. A commercial turbofan engine which has previously experienced icing events during operation in a high altitude ice crystal environment has been tested in the Propulsion Systems Laboratory (PSL) altitude test facility at NASA Glenn Research Center. The PSL has the capability to produce a continuous ice cloud which is ingested by the engine during operation over a range of altitude conditions. The PSL test results confirmed that there was ice accretion in the engine due to ice crystal ingestion, at the same simulated altitude operating conditions as experienced previously in

  3. Early history of high-altitude physiology.

    Science.gov (United States)

    West, John B

    2016-02-01

    High-altitude physiology can be said to have begun in 1644 when Torricelli described the first mercury barometer and wrote the immortal words "We live submerged at the bottom of an ocean of the element air." Interestingly, the notion of atmospheric pressure had eluded his teacher, the great Galileo. Blaise Pascal was responsible for describing the fall in pressure with increasing altitude, and Otto von Guericke gave a dramatic demonstration of the enormous force that could be developed by atmospheric pressure. Robert Boyle learned of Guericke's experiment and, with Robert Hooke, constructed the first air pump that allowed small animals to be exposed to a low pressure. Hooke also constructed a small low-pressure chamber and exposed himself to a simulated altitude of about 2400 meters. With the advent of ballooning, humans were rapidly exposed to very low pressures, sometimes with tragic results. For example, the French balloon, Zénith, rose to over 8000 m, and two of the three aeronauts succumbed to the hypoxia. Paul Bert was the first person to clearly state that the deleterious effects of high altitude were caused by the low partial pressure of oxygen (PO2), and later research was accelerated by high-altitude stations and expeditions to high altitude. © 2015 New York Academy of Sciences.

  4. Ice-based altitude distribution of natural radiation annual exposure rate in the Antarctica zone over the latitude range 69 deg S-77 deg S using a pair-filter thermoluminescence method

    International Nuclear Information System (INIS)

    Nakajima, Toshiyuki; Kamiyama, Takayoshi; Fujii, Yoshiyuki; Motoyama, Hideaki; Esumi, Shuuichi

    1995-01-01

    Both ice-based altitude distributions of natural ionizing radiation exposure and the quasi-effective energy of natural radiation over Antarctica over the latitude range 69 o S-77 o S during approx. 500 days were measured using thermoluminescent dosimeters. The results shows that dependence on altitude above sea level of the exposure rate increases by almost three-fold with each increase of 2000 m of altitude, thus deviating from the general rule stating that the exposure rate should double with each 2000 m. Although the exposure rate shows a dependence on altitude, altitude dependence of the quasi-effective energy of natural radiation over Antarctica is not observed. In the present study it is observed that natural radiation occurring over the ice base of Antarctica consists mainly of cosmic rays. (Author)

  5. Ice-based altitude distribution of natural radiation annual exposure rate in the Antarctica zone over the latitude range 69 degrees S-77 degrees S using a pair-filter thermoluminescence method.

    Science.gov (United States)

    Nakajima, T; Kamiyama, T; Fujii, Y; Motoyama, H; Esumi, S

    1995-12-01

    Both ice-based altitude distributions of natural ionizing radiation exposure and the quasi-effective energy of natural radiation over Antartica over the latitude range 69 degrees S - 77 degrees S during approx. 500 days were measured using thermoluminescent dosimeters. The results shows that dependence on altitude above sea level of the exposure rate increases by almost three-fold with each increase of 2000 m of altitude, thus deviating from the general rule stating that the exposure rate should double with each 2000 m. Although the exposure rate shows a dependence on altitude, altitude dependence of the quasi-effective energy of natural radiation over Antartica is not observed. In the present study it is observed that natural radiation occurring over the ice base of Antartica consists mainly of cosmic rays.

  6. The Horizontal Ice Nucleation Chamber (HINC: INP measurements at conditions relevant for mixed-phase clouds at the High Altitude Research Station Jungfraujoch

    Directory of Open Access Journals (Sweden)

    L. Lacher

    2017-12-01

    Full Text Available In this work we describe the Horizontal Ice Nucleation Chamber (HINC as a new instrument to measure ambient ice-nucleating particle (INP concentrations for conditions relevant to mixed-phase clouds. Laboratory verification and validation experiments confirm the accuracy of the thermodynamic conditions of temperature (T and relative humidity (RH in HINC with uncertainties in T of ±0.4 K and in RH with respect to water (RHw of ±1.5 %, which translates into an uncertainty in RH with respect to ice (RHi of ±3.0 % at T > 235 K. For further validation of HINC as a field instrument, two measurement campaigns were conducted in winters 2015 and 2016 at the High Altitude Research Station Jungfraujoch (JFJ; Switzerland, 3580 m a. s. l.  to sample ambient INPs. During winters 2015 and 2016 the site encountered free-tropospheric conditions 92 and 79 % of the time, respectively. We measured INP concentrations at 242 K at water-subsaturated conditions (RHw = 94 %, relevant for the formation of ice clouds, and in the water-supersaturated regime (RHw = 104 % to represent ice formation occurring under mixed-phase cloud conditions. In winters 2015 and 2016 the median INP concentrations at RHw = 94 % was below the minimum detectable concentration. At RHw = 104 %, INP concentrations were an order of magnitude higher, with median concentrations in winter 2015 of 2.8 per standard liter (std L−1; normalized to standard T of 273 K and pressure, p, of 1013 hPa and 4.7 std L−1 in winter 2016. The measurements are in agreement with previous winter measurements obtained with the Portable Ice Nucleation Chamber (PINC of 2.2 std L−1 at the same location. During winter 2015, two events caused the INP concentrations at RHw = 104 % to significantly increase above the campaign average. First, an increase to 72.1 std L−1 was measured during an event influenced by marine air, arriving at the JFJ

  7. On the Importance of High Frequency Gravity Waves for Ice Nucleation in the Tropical Tropopause Layer

    Science.gov (United States)

    Jensen, Eric J.

    2016-01-01

    Recent investigations of the influence of atmospheric waves on ice nucleation in cirrus have identified a number of key processes and sensitivities: (1) ice concentrations produced by homogeneous freezing are strongly dependent on cooling rates, with gravity waves dominating upper tropospheric cooling rates; (2) rapid cooling driven by high-frequency waves are likely responsible for the rare occurrences of very high ice concentrations in cirrus; (3) sedimentation and entrainment tend to decrease ice concentrations as cirrus age; and (4) in some situations, changes in temperature tendency driven by high-frequency waves can quench ice nucleation events and limit ice concentrations. Here we use parcel-model simulations of ice nucleation driven by long-duration, constant-pressure balloon temperature time series, along with an extensive dataset of cold cirrus microphysical properties from the recent ATTREX high-altitude aircraft campaign, to statistically examine the importance of high-frequency waves as well as the consistency between our theoretical understanding of ice nucleation and observed ice concentrations. The parcel-model simulations indicate common occurrence of peak ice concentrations exceeding several hundred per liter. Sedimentation and entrainment would reduce ice concentrations as clouds age, but 1-D simulations using a wave parameterization (which underestimates rapid cooling events) still produce ice concentrations higher than indicated by observations. We find that quenching of nucleation events by high-frequency waves occurs infrequently and does not prevent occurrences of large ice concentrations in parcel simulations of homogeneous freezing. In fact, the high-frequency variability in the balloon temperature data is entirely responsible for production of these high ice concentrations in the simulations.

  8. High Altitude Launch for a Practical SSTO

    Science.gov (United States)

    Landis, Geoffrey A.; Denis, Vincent

    2003-01-01

    Existing engineering materials allow the constuction of towers to heights of many kilometers. Orbital launch from a high altitude has significant advantages over sea-level launch due to the reduced atmospheric pressure, resulting in lower atmospheric drag on the vehicle and allowing higher rocket engine performance. High-altitude launch sites are particularly advantageous for single-stage to orbit (SSTO) vehicles, where the payload is typically 2% of the initial launch mass. An earlier paper enumerated some of the advantages of high altitude launch of SSTO vehicles. In this paper, we calculate launch trajectories for a candidate SSTO vehicle, and calculate the advantage of launch at launch altitudes 5 to 25 kilometer altitudes above sea level. The performance increase can be directly translated into increased payload capability to orbit, ranging from 5 to 20% increase in the mass to orbit. For a candidate vehicle with an initial payload fraction of 2% of gross lift-off weight, this corresponds to 31% increase in payload (for 5-km launch altitude) to 122% additional payload (for 25-km launch altitude).

  9. Estimating the top altitude of optically thick ice clouds from thermal infrared satellite observations using CALIPSO data

    Science.gov (United States)

    Minnis, Patrick; Yost, Chris R.; Sun-Mack, Sunny; Chen, Yan

    2008-06-01

    The difference between cloud-top altitude Z top and infrared effective radiating height Z eff for optically thick ice clouds is examined using April 2007 data taken by the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) and the Moderate-Resolution Imaging Spectroradiometer (MODIS). For even days, the difference ΔZ between CALIPSO Z top and MODIS Z eff is 1.58 +/- 1.26 km. The linear fit between Z top and Z eff , applied to odd-day data, yields a difference of 0.03 +/- 1.21 km and can be used to estimate Z top from any infrared-based Z eff for thick ice clouds. Random errors appear to be due primarily to variations in cloud ice-water content (IWC). Radiative transfer calculations show that ΔZ corresponds to an optical depth of ~1, which based on observed ice-particle sizes yields an average cloud-top IWC of ~0.015 gm-3, a value consistent with in situ measurements. The analysis indicates potential for deriving cloud-top IWC using dual-satellite data.

  10. Modeling of Highly Instrumented Honeywell Turbofan Engine Tested with Ice Crystal Ingestion in the NASA Propulsion System Laboratory

    Science.gov (United States)

    Veres, Joseph P.; Jorgenson, Philip C. E.; Jones, Scott M.

    2016-01-01

    The Propulsion Systems Laboratory (PSL), an altitude test facility at NASA Glenn Research Center, has been used to test a highly instrumented turbine engine at simulated altitude operating conditions. This is a continuation of the PSL testing that successfully duplicated the icing events that were experienced in a previous engine (serial LF01) during flight through ice crystal clouds, which was the first turbofan engine tested in PSL. This second model of the ALF502R-5A serial number LF11 is a highly instrumented version of the previous engine. The PSL facility provides a continuous cloud of ice crystals with controlled characteristics of size and concentration, which are ingested by the engine during operation at simulated altitudes. Several of the previous operating points tested in the LF01 engine were duplicated to confirm repeatability in LF11. The instrumentation included video cameras to visually illustrate the accretion of ice in the low pressure compressor (LPC) exit guide vane region in order to confirm the ice accretion, which was suspected during the testing of the LF01. Traditional instrumentation included static pressure taps in the low pressure compressor inner and outer flow path walls, as well as total pressure and temperature rakes in the low pressure compressor region. The test data was utilized to determine the losses and blockages due to accretion in the exit guide vane region of the LPC. Multiple data points were analyzed with the Honeywell Customer Deck. A full engine roll back point was modeled with the Numerical Propulsion System Simulation (NPSS) code. The mean line compressor flow analysis code with ice crystal modeling was utilized to estimate the parameters that indicate the risk of accretion, as well as to estimate the degree of blockage and losses caused by accretion during a full engine roll back point. The analysis provided additional validation of the icing risk parameters within the LPC, as well as the creation of models for

  11. The Late-Glacial and Holocene Marboré Lake sequence (2612 m a.s.l., Central Pyrenees, Spain): Testing high altitude sites sensitivity to millennial scale vegetation and climate variability

    Science.gov (United States)

    Leunda, Maria; González-Sampériz, Penélope; Gil-Romera, Graciela; Aranbarri, Josu; Moreno, Ana; Oliva-Urcia, Belén; Sevilla-Callejo, Miguel; Valero-Garcés, Blas

    2017-10-01

    This paper presents the environmental, climate and vegetation changes reconstructed for the last 14.6 kyr cal BP from the Marboré Lake sedimentary sequence, the highest altitude record (2612 m a.s.l.) in the Pyrenees studied up to date. We investigate the sensitivity of this high altitude site to vegetational and climate dynamics and altitudinal shifts during the Holocene by comparing palynological spectra of the fossil sequence and pollen rain content from current moss pollsters. We hypothesize that the input of sediments in lakes at such altitude is strongly controlled by ice phenology (ice-free summer months) and that during cold periods Pollen Accumulation Rate (PAR) and Pollen Concentration (PC) reflect changes in ice-cover and thus is linked to temperature changes. Low sedimentation rates and low PC and PAR occurred during colder periods as the Younger Dryas (GS-1) and the Holocene onset (12.6-10.2 kyr cal BP), suggesting that the lake-surface remained ice-covered for most of the year during these periods. Warmer conditions are not evident until 10.2 kyr cal BP, when an abrupt increase in sedimentation rate, PC and PAR occur, pointing to a delayed onset of the Holocene temperature increase at high altitude. Well-developed pinewoods and deciduous forest dominated the mid montane belt since 9.3 kyr cal BP until mid-Holocene (5.2 kyr cal BP). A downwards shift in the deciduous forest occurred after 5.2 kyr cal BP, in agreement with the aridity trend observed at a regional and Mediterranean context. The increase of herbaceous taxa during the late-Holocene (3.5 kyr cal BP-present) reflects a general trend to reduced montane forest, as anthropogenic disturbances were not evident until 1.3 kyr cal BP when Olea proportions from lowland areas and other anthropogenic indicators clearly expand. Our study demonstrates the need to perform local experimental approaches to check the effect of ice phenology on high altitude lakes sensitivity to vegetation changes to obtain

  12. DLR HABLEG- High Altitude Balloon Launched Experimental Glider

    Science.gov (United States)

    Wlach, S.; Schwarzbauch, M.; Laiacker, M.

    2015-09-01

    The group Flying Robots at the DLR Institute of Robotics and Mechatronics in Oberpfaffenhofen conducts research on solar powered high altitude aircrafts. Due to the high altitude and the almost infinite mission duration, these platforms are also denoted as High Altitude Pseudo-Satellites (HAPS). This paper highlights some aspects of the design, building, integration and testing of a flying experimental platform for high altitudes. This unmanned aircraft, with a wingspan of 3 m and a mass of less than 10 kg, is meant to be launched as a glider from a high altitude balloon in 20 km altitude and shall investigate technologies for future large HAPS platforms. The aerodynamic requirements for high altitude flight included the development of a launch method allowing for a safe transition to horizontal flight from free-fall with low control authority. Due to the harsh environmental conditions in the stratosphere, the integration of electronic components in the airframe is a major effort. For regulatory reasons a reliable and situation dependent flight termination system had to be implemented. In May 2015 a flight campaign was conducted. The mission was a full success demonstrating that stratospheric research flights are feasible with rather small aircrafts.

  13. High-altitude adaptations in vertebrate hemoglobins

    DEFF Research Database (Denmark)

    Weber, Roy E.

    2007-01-01

    Vertebrates at high altitude are subjected to hypoxic conditions that challenge aerobic metabolism. O2 transport from the respiratory surfaces to tissues requires matching between the O2 loading and unloading tensions and theO2-affinity of blood, which is an integrated function of hemoglobin......, birds and ectothermic vertebrates at high altitude....

  14. High-Altitude Illnesses: Physiology, Risk Factors, Prevention, and Treatment

    Directory of Open Access Journals (Sweden)

    Andrew T. Taylor

    2011-01-01

    Full Text Available High-altitude illnesses encompass the pulmonary and cerebral syndromes that occur in non-acclimatized individuals after rapid ascent to high altitude. The most common syndrome is acute mountain sickness (AMS which usually begins within a few hours of ascent and typically consists of headache variably accompanied by loss of appetite, nausea, vomiting, disturbed sleep, fatigue, and dizziness. With millions of travelers journeying to high altitudes every year and sleeping above 2,500 m, acute mountain sickness is a wide-spread clinical condition. Risk factors include home elevation, maximum altitude, sleeping altitude, rate of ascent, latitude, age, gender, physical condition, intensity of exercise, pre-acclimatization, genetic make-up, and pre-existing diseases. At higher altitudes, sleep disturbances may become more profound, mental performance is impaired, and weight loss may occur. If ascent is rapid, acetazolamide can reduce the risk of developing AMS, although a number of high-altitude travelers taking acetazolamide will still develop symptoms. Ibuprofen can be effective for headache. Symptoms can be rapidly relieved by descent, and descent is mandatory, if at all possible, for the management of the potentially fatal syndromes of high-altitude pulmonary and cerebral edema. The purpose of this review is to combine a discussion of specific risk factors, prevention, and treatment options with a summary of the basic physiologic responses to the hypoxia of altitude to provide a context for managing high-altitude illnesses and advising the non-acclimatized high-altitude traveler.

  15. Can High Altitude Influence Cytokines and Sleep?

    Directory of Open Access Journals (Sweden)

    Valdir de Aquino Lemos

    2013-01-01

    Full Text Available The number of persons who relocate to regions of high altitude for work, pleasure, sport, or residence increases every year. It is known that the reduced supply of oxygen (O2 induced by acute or chronic increases in altitude stimulates the body to adapt to new metabolic challenges imposed by hypoxia. Sleep can suffer partial fragmentation because of the exposure to high altitudes, and these changes have been described as one of the responsible factors for the many consequences at high altitudes. We conducted a review of the literature during the period from 1987 to 2012. This work explored the relationships among inflammation, hypoxia and sleep in the period of adaptation and examined a novel mechanism that might explain the harmful effects of altitude on sleep, involving increased Interleukin-1 beta (IL-1β, Interleukin-6 (IL-6, and tumor necrosis factor-alpha (TNF-α production from several tissues and cells, such as leukocytes and cells from skeletal muscle and brain.

  16. Can High Altitude Influence Cytokines and Sleep?

    Science.gov (United States)

    de Aquino Lemos, Valdir; dos Santos, Ronaldo Vagner Thomatieli; Lira, Fabio Santos; Rodrigues, Bruno; Tufik, Sergio; de Mello, Marco Tulio

    2013-01-01

    The number of persons who relocate to regions of high altitude for work, pleasure, sport, or residence increases every year. It is known that the reduced supply of oxygen (O2) induced by acute or chronic increases in altitude stimulates the body to adapt to new metabolic challenges imposed by hypoxia. Sleep can suffer partial fragmentation because of the exposure to high altitudes, and these changes have been described as one of the responsible factors for the many consequences at high altitudes. We conducted a review of the literature during the period from 1987 to 2012. This work explored the relationships among inflammation, hypoxia and sleep in the period of adaptation and examined a novel mechanism that might explain the harmful effects of altitude on sleep, involving increased Interleukin-1 beta (IL-1β), Interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) production from several tissues and cells, such as leukocytes and cells from skeletal muscle and brain. PMID:23690660

  17. The Impact of Altitude on Sleep-Disordered Breathing in Children Dwelling at High Altitude: A Crossover Study.

    Science.gov (United States)

    Hughes, Benjamin H; Brinton, John T; Ingram, David G; Halbower, Ann C

    2017-09-01

    Sleep-disordered breathing (SDB) is prevalent among children and is associated with adverse health outcomes. Worldwide, approximately 250 million individuals reside at altitudes higher than 2000 meters above sea level (masl). The effect of chronic high-altitude exposure on children with SDB is unknown. This study aims to determine the impact of altitude on sleep study outcomes in children with SDB dwelling at high altitude. A single-center crossover study was performed to compare results of high-altitude home polysomnography (H-PSG) with lower altitude laboratory polysomnography (L-PSG) in school-age children dwelling at high altitude with symptoms consistent with SDB. The primary outcome was apnea-hypopnea index (AHI), with secondary outcomes including obstructive AHI; central AHI; and measures of oxygenation, sleep quality, and pulse rate. Twelve participants were enrolled, with 10 included in the final analysis. Median altitude was 1644 masl on L-PSG and 2531 masl on H-PSG. Median AHI was 2.40 on L-PSG and 10.95 on H-PSG. Both obstructive and central respiratory events accounted for the difference in AHI. Oxygenation and sleep fragmentation were worse and pulse rate higher on H-PSG compared to L-PSG. These findings reveal a clinically substantial impact of altitude on respiratory, sleep, and cardiovascular outcomes in children with SDB who dwell at high altitude. Within this population, L-PSG underestimates obstructive sleep apnea and central sleep apnea compared to H-PSG. Given the shortage of high-altitude pediatric sleep laboratories, these results suggest a role for home sleep apnea testing for children residing at high altitude. © Sleep Research Society 2017. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

  18. Acute high-altitude illness | Hofmeyr | South African Medical Journal

    African Journals Online (AJOL)

    A substantial proportion of South Africa (SA)'s population lives at high altitude (>1 500 m), and many travel to very high altitudes (>3 500 m) for tourism, business, recreation or religious pilgrimages every year. Despite this, knowledge of acute altitude illnesses is poor among SA doctors. At altitude, the decreasing ambient ...

  19. The sleep of elite athletes at sea level and high altitude: a comparison of sea-level natives and high-altitude natives (ISA3600).

    Science.gov (United States)

    Roach, Gregory D; Schmidt, Walter F; Aughey, Robert J; Bourdon, Pitre C; Soria, Rudy; Claros, Jesus C Jimenez; Garvican-Lewis, Laura A; Buchheit, Martin; Simpson, Ben M; Hammond, Kristal; Kley, Marlen; Wachsmuth, Nadine; Gore, Christopher J; Sargent, Charli

    2013-12-01

    Altitude exposure causes acute sleep disruption in non-athletes, but little is known about its effects in elite athletes. The aim of this study was to examine the effects of altitude on two groups of elite athletes, that is, sea-level natives and high-altitude natives. Sea-level natives were members of the Australian under-17 soccer team (n=14). High-altitude natives were members of a Bolivian under-20 club team (n=12). Teams participated in an 18-day (19 nights) training camp in Bolivia, with 6 nights at near sea level in Santa Cruz (430 m) and 13 nights at high altitude in La Paz (3600 m). Sleep was assessed on every day/night using activity monitors. The Australians' sleep was shorter, and of poorer quality, on the first night at altitude compared with sea level. Sleep quality returned to normal by the end of the first week at altitude, but sleep quantity had still not stabilised at its normal level after 2 weeks. The quantity and quality of sleep obtained by the Bolivians was similar, or greater, on all nights at altitude compared with sea level. The Australians tended to obtain more sleep than the Bolivians at sea level and altitude, but the quality of the Bolivians' sleep tended to be better than that of the Australians at altitude. Exposure to high altitude causes acute and chronic disruption to the sleep of elite athletes who are sea-level natives, but it does not affect the sleep of elite athletes who are high-altitude natives.

  20. Preacclimatization in hypoxic chambers for high altitude sojourns.

    Science.gov (United States)

    Küpper, Thomas E A H; Schöffl, Volker

    2010-09-01

    Since hypoxic chambers are more and more available, they are used for preacclimatization to prepare for sojourns at high altitude. Since there are different protocols and the data differ, there is no general consensus about the standard how to perform preacclimatization by simulated altitude. The paper reviews the different types of exposure and focuses on the target groups which may benefit from preacclimatization. Since data about intermittent hypoxia for some hours per day to reduce the incidence of acute mountain sickness differ, it is suggested to perform preacclimatization by sleeping some nights at a simulated altitude which follows the altitude profile of the "gold standard" for high altitude acclimatization.

  1. Validation Ice Crystal Icing Engine Test in the Propulsion Systems Laboratory at NASA Glenn Research Center

    Science.gov (United States)

    Oliver, Michael J.

    2014-01-01

    The Propulsion Systems Laboratory (PSL) is an existing altitude simulation jet engine test facility located at NASA Glenn Research Center in Cleveland, OH. It was modified in 2012 with the integration of an ice crystal cloud generation system. This paper documents the inaugural ice crystal cloud test in PSL--the first ever full scale, high altitude ice crystal cloud turbofan engine test to be conducted in a ground based facility. The test article was a Lycoming ALF502-R5 high bypass turbofan engine, serial number LF01. The objectives of the test were to validate the PSL ice crystal cloud calibration and engine testing methodologies by demonstrating the capability to calibrate and duplicate known flight test events that occurred on the same LF01 engine and to generate engine data to support fundamental and computational research to investigate and better understand the physics of ice crystal icing in a turbofan engine environment while duplicating known revenue service events and conducting test points while varying facility and engine parameters. During PSL calibration testing it was discovered than heated probes installed through tunnel sidewalls experienced ice buildup aft of their location due to ice crystals impinging upon them, melting and running back. Filtered city water was used in the cloud generation nozzle system to provide ice crystal nucleation sites. This resulted in mineralization forming on flow path hardware that led to a chronic degradation of performance during the month long test. Lacking internal flow path cameras, the response of thermocouples along the flow path was interpreted as ice building up. Using this interpretation, a strong correlation between total water content (TWC) and a weaker correlation between median volumetric diameter (MVD) of the ice crystal cloud and the rate of ice buildup along the instrumented flow path was identified. For this test article the engine anti-ice system was required to be turned on before ice crystal

  2. High-Altitude-Induced alterations in Gut-Immune Axis: A review.

    Science.gov (United States)

    Khanna, Kunjan; Mishra, K P; Ganju, Lilly; Kumar, Bhuvnesh; Singh, Shashi Bala

    2018-03-04

    High-altitude sojourn above 8000 ft is increasing day by day either for pilgrimage, mountaineering, holidaying or for strategic reasons. In India, soldiers are deployed to these high mountains for their duty or pilgrims visit to the holy places, which are located at very high altitude. A large population also resides permanently in high altitude regions. Every year thousands of pilgrims visit Holy cave of Shri Amarnath ji, which is above 15 000 ft. The poor acclimatization to high altitude may cause alteration in immunity. The low oxygen partial pressure may cause alterations in gut microbiota, which may cause changes in gut immunity. Effect of high altitude on gut-associated mucosal system is new area of research. Many studies have been carried out to understand the physiology and immunology behind the high-altitude-induced gut problems. Few interventions have also been discovered to circumvent the problems caused due to high-altitude conditions. In this review, we have discussed the effects of high-altitude-induced changes in gut immunity particularly peyer's patches, NK cells and inflammatory cytokines, secretary immunoglobulins and gut microbiota. The published articles from PubMed and Google scholar from year 1975 to 2017 on high-altitude hypoxia and gut immunity are cited in this review.

  3. The sleep of elite athletes at sea level and high altitude: a comparison of sea-level natives and high-altitude natives (ISA3600)

    Science.gov (United States)

    Roach, Gregory D; Schmidt, Walter F; Aughey, Robert J; Bourdon, Pitre C; Soria, Rudy; Claros, Jesus C Jimenez; Garvican-Lewis, Laura A; Buchheit, Martin; Simpson, Ben M; Hammond, Kristal; Kley, Marlen; Wachsmuth, Nadine; Gore, Christopher J; Sargent, Charli

    2013-01-01

    Background Altitude exposure causes acute sleep disruption in non-athletes, but little is known about its effects in elite athletes. The aim of this study was to examine the effects of altitude on two groups of elite athletes, that is, sea-level natives and high-altitude natives. Methods Sea-level natives were members of the Australian under-17 soccer team (n=14). High-altitude natives were members of a Bolivian under-20 club team (n=12). Teams participated in an 18-day (19 nights) training camp in Bolivia, with 6 nights at near sea level in Santa Cruz (430 m) and 13 nights at high altitude in La Paz (3600 m). Sleep was assessed on every day/night using activity monitors. Results The Australians’ sleep was shorter, and of poorer quality, on the first night at altitude compared with sea level. Sleep quality returned to normal by the end of the first week at altitude, but sleep quantity had still not stabilised at its normal level after 2 weeks. The quantity and quality of sleep obtained by the Bolivians was similar, or greater, on all nights at altitude compared with sea level. The Australians tended to obtain more sleep than the Bolivians at sea level and altitude, but the quality of the Bolivians’ sleep tended to be better than that of the Australians at altitude. Conclusions Exposure to high altitude causes acute and chronic disruption to the sleep of elite athletes who are sea-level natives, but it does not affect the sleep of elite athletes who are high-altitude natives. PMID:24282197

  4. Effects of ascent to high altitude on human antimycobacterial immunity.

    Directory of Open Access Journals (Sweden)

    Sarah Eisen

    Full Text Available Tuberculosis infection, disease and mortality are all less common at high than low altitude and ascent to high altitude was historically recommended for treatment. The immunological and mycobacterial mechanisms underlying the association between altitude and tuberculosis are unclear. We studied the effects of altitude on mycobacteria and antimycobacterial immunity.Antimycobacterial immunity was assayed in 15 healthy adults residing at low altitude before and after they ascended to 3400 meters; and in 47 long-term high-altitude residents. Antimycobacterial immunity was assessed as the extent to which participants' whole blood supported or restricted growth of genetically modified luminescent Bacille Calmette-Guérin (BCG mycobacteria during 96 hours incubation. We developed a simplified whole blood assay that could be used by a technician in a low-technology setting. We used this to compare mycobacterial growth in participants' whole blood versus positive-control culture broth and versus negative-control plasma.Measurements of mycobacterial luminescence predicted the number of mycobacterial colonies cultured six weeks later. At low altitude, mycobacteria grew in blood at similar rates to positive-control culture broth whereas ascent to high altitude was associated with restriction (p ≤ 0.002 of mycobacterial growth to be 4-times less than in culture broth. At low altitude, mycobacteria grew in blood 25-times more than negative-control plasma whereas ascent to high altitude was associated with restriction (p ≤ 0.01 of mycobacterial growth to be only 6-times more than in plasma. There was no evidence of differences in antimycobacterial immunity at high altitude between people who had recently ascended to high altitude versus long-term high-altitude residents.An assay of luminescent mycobacterial growth in whole blood was adapted and found to be feasible in low-resource settings. This demonstrated that ascent to or residence at high altitude was

  5. [Hemoglobin and testosterone: importance on high altitude acclimatization and adaptation].

    Science.gov (United States)

    Gonzales, Gustavo F

    2011-03-01

    The different types of response mechanisms that the organism uses when exposed to hypoxia include accommodation, acclimatization and adaptation. Accommodation is the initial response to acute exposure to high altitude hypoxia and is characterized by an increase in ventilation and heart rate. Acclimatization is observed in individuals temporarily exposed to high altitude, and to some extent, it enables them to tolerate the high altitudes. In this phase, erythropoiesis is increased, resulting in higher hemoglobin and hematocrit levels to improve oxygen delivery capacity. Adaptation is the process of natural acclimatization where genetical variations and acclimatization play a role in allowing subjects to live without any difficulties at high altitudes. Testosterone is a hormone that regulates erythropoiesis and ventilation and could be associated to the processes of acclimatization and adaptation to high altitude. Excessive erythrocytosis, which leads to chronic mountain sickness, is caused by low arterial oxygen saturation, ventilatory inefficiency and reduced ventilatory response to hypoxia. Testosterone increases during acute exposure to high altitude and also in natives at high altitude with excessive erythrocytosis. Results of current research allow us to conclude that increase in serum testosterone and hemoglobin is adequate for acclimatization, as they improve oxygen transport, but not for high altitude adaptation, since high serum testosterone levels are associated to excessive erythrocytosis.

  6. Pathology of high altitude pulmonary oedema

    International Nuclear Information System (INIS)

    Saleem, N.

    2014-01-01

    Objective: To describe autopsy findings in fatal cases of high altitude pulmonary oedema. Study Design: Descriptive study. Place and Duration of Study: The study was carried out between 1999 and 2002 at an army field medical unit in Baltistan, Armed Forces Institute of Pathology, Rawalpindi and Army Medical College, Rawalpindi, Pakistan. Patients and Methods:Autopsies were performed in 17 fatal cases of High Altitude Pulmonary Edema (HAPE) occurring among soldiers serving in Siachen. Results:All cases were males with a mean age of 26.8 years (19-35). The mean altitude at which HAPE occurred was 5192 meters (2895-6492), and the mean duration of stay at these altitudes was 15.3 days (1-30). Eleven individuals had undergone proper acclimatization. The commonest clinical findings were cough (70%), dyspnoea (53%), nausea (47%), headache (41%), vomiting (35%), chest pain (35%) and tightness in chest (24%). Cyanosis and frothy secretions in the nostrils and mouth were present in all but one case. Mean combined weight of lungs was 1470 grams (1070-1810). There was marked congestion of outer and cut surfaces. Interstitial oedema was present in all cases. RBCs and leukocyte infiltrates were seen in 13 and alveolar hyaline membranes in 9 cases. Thrombi were seen in 2 cases. Cerebral oedema was present in 9 cases. Conclusion:HAPE can occur after more than two weeks of stay at high altitudes despite proper acclimatization. Concomitant cerebral oedema is frequently present. Our autopsy findings are consistent with what has been reported previously. (author)

  7. Atmospheric heavy metals in tropical South America during the past 22,000 years recorded in a high altitude ice core from Sajama, Bolivia.

    Science.gov (United States)

    Hong, Sungmin; Barbante, Carlo; Boutron, Claude; Gabrielli, Paolo; Gaspari, Vania; Cescon, Paolo; Thompson, Lonnie; Ferrari, Christophe; Francou, Bernard; Maurice-Bourgoin, Laurence

    2004-04-01

    V, Co, Cu, Zn, As, Rb, Sr, Ag, Cd, Ba, Pb, Bi and U have been analysed by inductively coupled plasma sector field mass spectrometry in various sections of a dated snow/ice core drilled at an altitude of 6542 m on the Sajama ice cap in Bolivia. The analysed sections were dated from the Last Glacial Stage ( approximately 22,000 years ago), the Mid-Holocene and the last centuries. The observed variations of crustal enrichment factors (EFc) for the various metals show contrasting situations. For V, Co, Rb, Sr and U, EFc values close to unity are observed for all sections, then showing that these elements are mainly derived from rock and soil dust. For the other metals, clear time trends are observed, with a pronounced increase of EFc values during the 19th and 20th centuries. This increase shows evidence of metal pollution associated with human activity in South America. For Pb an important contribution was from gasoline additives. For metals such as Cu, Zn, Ag and Cd an important contribution was from metal production activities, with a continuous increase of production during the 20th century in countries such as Peru, Chile and Bolivia.

  8. High altitude organic gold

    DEFF Research Database (Denmark)

    Pouliot, Mariève; Pyakurel, Dipesh; Smith-Hall, Carsten

    2018-01-01

    Ethnopharmacological relevance Ophiocordyceps sinensis (Berk.) G.H.Sung, J.M.Sung, Hywel-Jones & Spatafora, a high altitude Himalayan fungus-caterpillar product found in alpine meadows in China, Bhutan, Nepal, and India, has been used in the Traditional Chinese Medicine system for over 2000 years...

  9. Why Are High Altitude Natives So Strong at High Altitude? Nature vs. Nurture: Genetic Factors vs. Growth and Development.

    Science.gov (United States)

    Brutsaert, Tom

    Among high-altitude natives there is evidence of a general hypoxia tolerance leading to enhanced performance and/or increased capacity in several important domains. These domains likely include an enhanced physical work capacity, an enhanced reproductive capacity, and an ability to resist several common pathologies of chronic high-altitude exposure. The "strength" of the high-altitude native in this regard may have both a developmental and a genetic basis, although there is better evidence for the former (developmental effects) than for the latter. For example, early-life hypoxia exposure clearly results in lung growth and remodeling leading to an increased O2 diffusing capacity in adulthood. Genetic research has yet to reveal a population genetic basis for enhanced capacity in high-altitude natives, but several traits are clearly under genetic control in Andean and Tibetan populations e.g., resting and exercise arterial O2 saturation (SaO2). This chapter reviews the effects of nature and nurture on traits that are relevant to the process of gas exchange, including pulmonary volumes and diffusion capacity, the maximal oxygen consumption (VO2max), the SaO2, and the alveolar-arterial oxygen partial pressure difference (A-aDO2) during exercise.

  10. CAMEX-4 ER-2 HIGH ALTITUDE DROPSONDE V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The CAMEX-4 ER-2 High Altitude Dropsonde dataset was collected by the ER-2 High Altitude Dropsonde System (EHAD), which used dropwinsondes fitted with Global...

  11. Fundamental Ice Crystal Accretion Physics Studies

    Science.gov (United States)

    Struk, Peter M.; Broeren, Andy P.; Tsao, Jen-Ching; Vargas, Mario; Wright, William B.; Currie, Tom; Knezevici, Danny; Fuleki, Dan

    2012-01-01

    Due to numerous engine power-loss events associated with high-altitude convective weather, ice accretion within an engine due to ice crystal ingestion is being investigated. The National Aeronautics and Space Administration (NASA) and the National Research Council (NRC) of Canada are starting to examine the physical mechanisms of ice accretion on surfaces exposed to ice-crystal and mixed-phase conditions. In November 2010, two weeks of testing occurred at the NRC Research Altitude Facility utilizing a single wedge-type airfoil designed to facilitate fundamental studies while retaining critical features of a compressor stator blade or guide vane. The airfoil was placed in the NRC cascade wind tunnel for both aerodynamic and icing tests. Aerodynamic testing showed excellent agreement compared with CFD data on the icing pressure surface and allowed calculation of heat transfer coefficients at various airfoil locations. Icing tests were performed at Mach numbers of 0.2 to 0.3, total pressures from 93 to 45 kPa, and total temperatures from 5 to 15 C. Ice and liquid water contents ranged up to 20 and 3 g/m3, respectively. The ice appeared well adhered to the surface in the lowest pressure tests (45 kPa) and, in a particular case, showed continuous leading-edge ice growth to a thickness greater than 15 mm in 3 min. Such widespread deposits were not observed in the highest pressure tests, where the accretions were limited to a small area around the leading edge. The suction surface was typically ice-free in the tests at high pressure, but not at low pressure. The icing behavior at high and low pressure appeared to be correlated with the wet-bulb temperature, which was estimated to be above 0 C in tests at 93 kPa and below 0 C in tests at lower pressure, the latter enhanced by more evaporative cooling of water. The authors believe that the large ice accretions observed in the low pressure tests would undoubtedly cause the aerodynamic performance of a compressor component

  12. Ice Motion and Topography Near Margin Areas of Kamb Ice Stream, Antarctica, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set includes ice motion and topography measurements that were taken by measuring movement and altitude of poles set in the West Antarctic Ice Shelf. The...

  13. Effects of altitude and exercise on pulmonary capillary integrity: evidence for subclinical high-altitude pulmonary edema.

    Science.gov (United States)

    Eldridge, Marlowe W; Braun, Ruedi K; Yoneda, Ken Y; Walby, William F

    2006-03-01

    Strenuous exercise may be a significant contributing factor for development of high-altitude pulmonary edema, particularly at low or moderate altitudes. Thus we investigated the effects of heavy cycle ergometer exercise (90% maximal effort) under hypoxic conditions in which the combined effects of a marked increase in pulmonary blood flow and nonuniform hypoxic pulmonary vasoconstriction could add significantly to augment the mechanical stress on the pulmonary microcirculation. We postulated that intense exercise at altitude would result in an augmented permeability edema. We recruited eight endurance athletes and examined their bronchoalveolar lavage fluid (BALF) for red blood cells (RBCs), protein, inflammatory cells, and soluble mediators at 2 and 26 h after intense exercise under normoxic and hypoxic conditions. After heavy exercise, under all conditions, the athletes developed a permeability edema with high BALF RBC and protein concentrations in the absence of inflammation. We found that exercise at altitude (3,810 m) caused significantly greater leakage of RBCs [9.2 (SD 3.1)x10(4) cells/ml] into the alveolar space than that seen with normoxic exercise [5.4 (SD 1.2)x10(4) cells/ml]. At altitude, the 26-h postexercise BALF revealed significantly higher RBC and protein concentrations, suggesting an ongoing capillary leak. Interestingly, the BALF profiles following exercise at altitude are similar to that of early high-altitude pulmonary edema. These findings suggest that pulmonary capillary disruption occurs with intense exercise in healthy humans and that hypoxia augments the mechanical stresses on the pulmonary microcirculation.

  14. Effect of oxygen supplementation in a hatchery at high altitude and ...

    African Journals Online (AJOL)

    The objective of this study was to investigate the effect of oxygen supplementation on broiler eggs in a hatchery at high altitude on the growth performance and ascites syndrome of broilers reared at low altitude. The treatment groups were low altitude with no oxygen supplemented in the hatchery (LA-NOX); high altitude with ...

  15. Chernobyl radioactivity and high altitude air-particulate monitoring at Islamabad

    International Nuclear Information System (INIS)

    Bhatti, M.S.; Ihsanullah; Shafiq, M.; Perveen, N.; Orfi, S.D.

    1987-11-01

    High altitude sampling of air particulates for radioactivity monitoring was conducted at Islamabad after the CHERNOBYL accident. Smears from aeroplanes flying at varying altitudes were collected and analysed for fresh fission products mainly gamma emitters e.g. Ru-103 and Cs-137 etc. The maximum radioactivity observed was of the order of 15Bq/sample for Ru-103 and 9Bq/sample for Cs-137 respectively. The study was purely qualitative in nature indicated the presence of fresh fission radioactivity at high altitudes over Islamabad. For quantitative measurements at high altitudes sophisticated instrumentation/procedure needs to be adopted. (author)

  16. Hemoglobin and testosterone: importance on high altitude acclimatization and adaptation

    OpenAIRE

    Gonzales, Gustavo F.; Jefe de la Unidad de Reproducción, Instituto de Investigaciones de la Altura y Jefe del Laboratorio de Endocrinología y Reproducción, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia. Doctor en Medicina y Doctor en Ciencias. Especialista en Endocrinología.

    2011-01-01

    The different types of response mechanisms that the organism uses when exposed to hypoxia include accommodation, acclimatization and adaptation. Accommodation is the initial response to acute exposure to high altitude hypoxia and is characterized by an increase in ventilation and heart rate. Acclimatization is observed in individuals temporarily exposed to high altitude, and to some extent, it enables them to tolerate the high altitudes. In this phase, erythropoiesis is increased, resulti...

  17. Can people with Raynaud's phenomenon travel to high altitude?

    Science.gov (United States)

    Luks, Andrew M; Grissom, Colin K; Jean, Dominique; Swenson, Erik R

    2009-01-01

    To determine whether high altitude travel adversely affects mountain enthusiasts with Raynaud's phenomenon. Volunteers with Raynaud's phenomenon were recruited using announcements disseminated by organizations dedicated to climbing or wilderness travel and Internet discussion boards dedicated to mountain activities to complete an online, anonymous survey. Survey questions addressed demographic variables, aspects of their Raynaud's phenomenon, and features of their mountain activities. Respondents compared experiences with Raynaud's phenomenon between high (>2440 m; 8000 feet) and low elevations and rated agreement with statements concerning their disease and the effects of high altitude. One hundred forty-two people, 98% of whom had primary Raynaud's phenomenon, completed the questionnaire. Respondents spent 5 to 7 days per month at elevations above 2440 m and engaged in 5.4 +/- 2.0 different activities. Eighty-nine percent of respondents engaged in winter sports and only 22% reported changing their mountain activities because of Raynaud's phenomenon. Respondents reported a variety of tactics to prevent and treat Raynaud's attacks, but only 12% used prophylactic medications. Fifteen percent of respondents reported an episode of frostbite following a Raynaud's phenomenon attack at high altitude. There was considerable heterogeneity in participants' perceptions of the frequency, duration, and severity of attacks at high altitude compared to their home elevation. Motivated individuals with primary Raynaud's phenomenon, employing various prevention and treatment strategies, can engage in different activities, including winter sports, at altitudes above 2440 m. Frostbite may be common in this population at high altitude, and care must be taken to prevent its occurrence.

  18. Ocular morbidity among porters at high altitudes.

    Science.gov (United States)

    Gnyawali, Subodh; Shrestha, Gauri Shankar; Khanal, Safal; Dennis, Talisa; Spencer, John C

    2017-01-01

    High altitude, often characterized by settings over 2400m, can be detrimental to the human body and pose a significant risk to ocular health. Reports concerning various ocular morbidities occurring as a consequence of high altitude are limited in the current literature. This study was aimed at evaluating the ocular health of porters working at high altitudesof Himalayas in Nepal. A mobile eye clinic was set up in Ghat and patient data were collected from its out- patient unit by a team of seven optometrists which was run for five days. Ghat is a small village in north-eastern Nepal, located at 2860 m altitude. Travellers walking through the trekking route were invited to get their eyes checked at the clinic. Comprehensive ocular examinations were performed, including visual acuities, objective and subjective refraction, anterior and posterior segment evaluations, and intraocular pressure measurements; blood pressure and blood glucose levels were also measured as required. Ocular therapeutics, prescription glasses, sunglasses and ocular health referrals were provided free of cost as necessary. A total of 1890 people visited the eye clinic, among which 57.4% (n=1084) were porters. Almost half of the porters had an ocular morbidity. Correctable refractive error was most prevalent, with other ocular health-related complications, including dry eye disease, infectious disorders, glaucoma and cataract. Proper provision of regular and effective eye care services should be made more available for those residing at these high altitudes in Nepal. © NEPjOPH.

  19. Ice nucleation and dehydration in the Tropical Tropopause Layer.

    Science.gov (United States)

    Jensen, Eric J; Diskin, Glenn; Lawson, R Paul; Lance, Sara; Bui, T Paul; Hlavka, Dennis; McGill, Matthew; Pfister, Leonhard; Toon, Owen B; Gao, Rushan

    2013-02-05

    Optically thin cirrus near the tropical tropopause regulate the humidity of air entering the stratosphere, which in turn has a strong influence on the Earth's radiation budget and climate. Recent high-altitude, unmanned aircraft measurements provide evidence for two distinct classes of cirrus formed in the tropical tropopause region: (i) vertically extensive cirrus with low ice number concentrations, low extinctions, and large supersaturations (up to ∼70%) with respect to ice; and (ii) vertically thin cirrus layers with much higher ice concentrations that effectively deplete the vapor in excess of saturation. The persistent supersaturation in the former class of cirrus is consistent with the long time-scales (several hours or longer) for quenching of vapor in excess of saturation given the low ice concentrations and cold tropical tropopause temperatures. The low-concentration clouds are likely formed on a background population of insoluble particles with concentrations less than 100 L(-1) (often less than 20 L(-1)), whereas the high ice concentration layers (with concentrations up to 10,000 L(-1)) can only be produced by homogeneous freezing of an abundant population of aqueous aerosols. These measurements, along with past high-altitude aircraft measurements, indicate that the low-concentration cirrus occur frequently in the tropical tropopause region, whereas the high-concentration cirrus occur infrequently. The predominance of the low-concentration clouds means cirrus near the tropical tropopause may typically allow entry of air into the stratosphere with as much as ∼1.7 times the ice saturation mixing ratio.

  20. Shape memory alloy resistance behaviour at high altitude for feedback control

    Science.gov (United States)

    Ng, W. T.; Sedan, M. F.; Abdullah, E. J.; Azrad, S.; Harithuddin, A. S. M.

    2017-12-01

    Many recent aerospace technologies are using smart actuators to reduce the system's complexity and increase its reliability. One such actuator is shape memory alloy (SMA) actuator, which is lightweight, produces high force and large deflection. However, some disadvantages in using SMA actuators have been identified and they include nonlinear response of the strain to input current, hysteresis characteristic that results in inaccurate control and less than optimum system performance, high operating temperatures, slow response and also high requirement of electrical power to obtain the desired actuation forces. It is still unknown if the SMA actuators can perform effectively at high altitude with low surrounding temperature. The work presented here covers the preliminary process of verifying the feasibility of using resistance as feedback control at high altitude for aerospace applications. Temperature and resistance of SMA actuator at high altitude is investigated by conducting an experiment onboard a high altitude balloon. The results from the high altitude experiment indicate that the resistance or voltage drop of the SMA wire is not significantly affected by the low surrounding temperature at high altitude as compared to the temperature of SMA. Resistance feedback control for SMA actuators may be suitable for aerospace applications.

  1. Phenotypic plasticity and genetic adaptation to high-altitude hypoxia in vertebrates.

    Science.gov (United States)

    Storz, Jay F; Scott, Graham R; Cheviron, Zachary A

    2010-12-15

    High-altitude environments provide ideal testing grounds for investigations of mechanism and process in physiological adaptation. In vertebrates, much of our understanding of the acclimatization response to high-altitude hypoxia derives from studies of animal species that are native to lowland environments. Such studies can indicate whether phenotypic plasticity will generally facilitate or impede adaptation to high altitude. Here, we review general mechanisms of physiological acclimatization and genetic adaptation to high-altitude hypoxia in birds and mammals. We evaluate whether the acclimatization response to environmental hypoxia can be regarded generally as a mechanism of adaptive phenotypic plasticity, or whether it might sometimes represent a misdirected response that acts as a hindrance to genetic adaptation. In cases in which the acclimatization response to hypoxia is maladaptive, selection will favor an attenuation of the induced phenotypic change. This can result in a form of cryptic adaptive evolution in which phenotypic similarity between high- and low-altitude populations is attributable to directional selection on genetically based trait variation that offsets environmentally induced changes. The blunted erythropoietic and pulmonary vasoconstriction responses to hypoxia in Tibetan humans and numerous high-altitude birds and mammals provide possible examples of this phenomenon. When lowland animals colonize high-altitude environments, adaptive phenotypic plasticity can mitigate the costs of selection, thereby enhancing prospects for population establishment and persistence. By contrast, maladaptive plasticity has the opposite effect. Thus, insights into the acclimatization response of lowland animals to high-altitude hypoxia can provide a basis for predicting how altitudinal range limits might shift in response to climate change.

  2. A brief introduction to high altitude nuclear explosion and a review on high altitude nuclear tests of usa and former USSR

    International Nuclear Information System (INIS)

    Sun Jingwen

    1999-11-01

    The author briefly introduces some knowledge about high altitude nuclear explosion (HANE) and presents a general review on high altitude nuclear tests of USA and former USSR. Physical phenomenon generated by HANE is given. The effects of HANE on space flyer, artificial satellite and communication are discussed. Some aspects of a mechanism of antimissile for HANE are described and the effect and role of HANE for USA and USSR are reviewed

  3. Research progress on high altitude retinopathy and application of Traditional Chinese Medicine

    Directory of Open Access Journals (Sweden)

    Hai-Xiang Huang

    2014-11-01

    Full Text Available High altitude retinopathy(HARrefers to the body which can't adapt to the hypobaric hypoxia environment at high altitude leading to retinal diseases, which typically manifested as retinal hemorrhages, optic disc edema and cotton wool spots. With the development of high altitude medicine, HAR become a hot topic of eye research in recent years. New researches show a significantly higher incidence of HAR, and HAR has a close contact with acute mountain sickness, high altitude cerebral edema and high altitude pulmonary edema. A further study in pathogenesis and prevention measures of HAR will promote the prevention of altitude sickness. Traditional Chinese Medicine has achieved good effects in the prevention of altitude sickness, but the effect and mechanism of herbs on HAR has not been reported. Through read and summarize the relevant literatures and reports, the author will give an overview of the research advances on HAR's pathogenesis and application of Traditional Chinese Medicine.

  4. Exploring the Limits of High Altitude GPS for Future Lunar Missions

    Science.gov (United States)

    Ashman, Benjamin W.; Parker, Joel J. K.; Bauer, Frank H.; Esswein, Michael

    2018-01-01

    An increasing number of spacecraft are relying on the Global Positioning System (GPS) for navigation at altitudes near or above the GPS constellation itself - the region known as the Space Service Volume (SSV). While the formal definition of the SSV ends at geostationary altitude, the practical limit of high-altitude space usage is not known, and recent missions have demonstrated that signal availability is sufficient for operational navigation at altitudes halfway to the moon. This paper presents simulation results based on a high-fidelity model of the GPS constellation, calibrated and validated through comparisons of simulated GPS signal availability and strength with flight data from recent high-altitude missions including the Geostationary Operational Environmental Satellite 16 (GOES-16) and the Magnetospheric Multiscale (MMS) mission. This improved model is applied to the transfer to a lunar near-rectilinear halo orbit (NRHO) of the class being considered for the international Deep Space Gateway concept. The number of GPS signals visible and their received signal strengths are presented as a function of receiver altitude in order to explore the practical upper limit of high-altitude space usage of GPS.

  5. AltitudeOmics: Resetting of cerebrovascular CO2 reactivity following acclimatization to high altitude

    Directory of Open Access Journals (Sweden)

    Jui-Lin eFan

    2016-01-01

    Full Text Available Previous studies reported enhanced cerebrovascular CO2 reactivity upon ascent to high altitude using linear models. However, there is evidence that this response may be sigmoidal in nature. Moreover, it was speculated that these changes at high altitude are mediated by alterations in acid-base buffering. Accordingly, we reanalyzed previously published data to assess middle cerebral blood flow velocity (MCAv responses to modified rebreathing at sea level (SL, upon ascent (ALT1 and following 16 days of acclimatization (ALT16 to 5,260 m in 21 lowlanders. Using sigmoid curve fitting of the MCAv responses to CO2, we found the amplitude (95% vs. 129%, SL vs. ALT1, 95% confidence intervals (CI [77, 112], [111, 145], respectively, P=0.024 and the slope of the sigmoid response (4.5 vs. 7.5 %/mmHg, SL vs. ALT1, 95% CIs [3.1, 5.9], [6.0, 9.0], respectively, P=0.026 to be enhanced at ALT1, which persisted with acclimatization at ALT16 (amplitude: 177%, 95% CI [139, 215], P<0.001; slope: 10.3 %/mmHg, 95% CI [8.2, 12.5], P=0.003 compared to SL. Meanwhile, the sigmoidal response midpoint was unchanged at ALT1 (SL: 36.5 mmHg; ALT1: 35.4 mmHg, 95% CIs [34.0, 39.0], [33.1, 37.7], respectively, P=0.982, while it was reduced by ~7 mmHg at ALT16 (28.6 mmHg, 95% CI [26.4, 30.8], P=0.001 vs. SL, indicating leftward shift of the cerebrovascular CO2 response to a lower arterial partial pressure of CO2 (PaCO2 following acclimatization to altitude. Sigmoid fitting revealed a leftward shift in the midpoint of the cerebrovascular response curve which could not be observed with linear fitting. These findings demonstrate that there is resetting of the cerebrovascular CO2 reactivity operating point to a lower PaCO2 following acclimatization to high altitude. This cerebrovascular resetting is likely the result of an altered acid-base buffer status resulting from prolonged exposure to the severe hypocapnia associated with ventilatory acclimatization to high altitude.

  6. Radiation exposure and high-altitude flight. NCRP Commentary No. 12

    International Nuclear Information System (INIS)

    1995-01-01

    Enhanced air crew and public radiation exposure while flying at current altitudes and speeds has not been adequately addressed. However, the commercial aircraft industry continues to expand with greater numbers of passengers and more air crews year by year. With the expected expansions in high-altitude flight in the next two decades there will be many more people exposed to higher levels of ionizing radiation than currently. The equivalent dose rates at the higher altitudes are of the order of two to three times those received at current aircraft altitudes, but are not known very well, partly because of limitations in the knowledge of the component radiations, especially the high-energy neutron component. The risks are also more uncertain than for low-LET exposures on the ground because of uncertainty in an average W R to use for high-LET radiations. Exposures of current air crew are presently comparable with the average exposures of other radiation workers on the ground (EPA, 1995). Substantially higher exposures must be expected at high altitudes to air crew (perhaps approaching or possibly exceeding the current limit for workers on the ground). Higher exposures to sensitive groups of the population such as the fetuses carried by pregnant women are of special concern. Therefore, steps must be taken to improve our knowledge base with respect to dose levels and risks at these high altitudes. Following acquisition of this knowledge, modifications in radiation protection practices with respect to air crew and passengers will need to be considered and recommended to assure that adequate radiation protection is provided with respect to high-altitude flight

  7. Autophagy Is a Promoter for Aerobic Exercise Performance during High Altitude Training

    Directory of Open Access Journals (Sweden)

    Ying Zhang

    2018-01-01

    Full Text Available High altitude training is one of the effective strategies for improving aerobic exercise performance at sea level via altitude acclimatization, thereby improving oxygen transport and/or utilization. But its underlying molecular mechanisms on physiological functions and exercise performance of athletes are still vague. More recent evidence suggests that the recycling of cellular components by autophagy is an important process of the body involved in the adaptive responses to exercise. Whether high altitude training can activate autophagy or whether high altitude training can improve exercise performance through exercise-induced autophagy is still unclear. In this narrative review article, we will summarize current research advances in the improvement of exercise performance through high altitude training and its reasonable molecular mechanisms associated with autophagy, which will provide a new field to explore the molecular mechanisms of adaptive response to high altitude training.

  8. Numerical simulation of the ionization effects of low- and high-altitude nuclear explosions

    International Nuclear Information System (INIS)

    Zhao Zhengyu; Wang Xiang

    2007-01-01

    Low-altitude and high-altitude nuclear explosions are sources of intensive additional ionization in ionosphere. In this paper, in terms of the ionization equilibrium equation system and the equation of energy deposition of radiation in atmosphere, and considering the influence of atmosphere, the temporal and spatial distribution of ionization effects caused by atmospheric nuclear detonation are investigated. The calculated results show that the maximum of additional free electron density produced by low-altitude nuclear explosion is greater than that by the high-altitude nuclear burst. As to the influence of instant nuclear radiation, there is obvious difference between the low-altitude and the high-altitude explosions. The influence range and the continuance time caused by delayed nuclear radiation is less for the low-altitude nuclear detonation than that for the high-altitude one. (authors)

  9. Glucose Homeostasis During Short-term and Prolonged Exposure to High Altitudes

    Science.gov (United States)

    Ader, Marilyn; Bergman, Richard N.

    2015-01-01

    Most of the literature related to high altitude medicine is devoted to the short-term effects of high-altitude exposure on human physiology. However, long-term effects of living at high altitudes may be more important in relation to human disease because more than 400 million people worldwide reside above 1500 m. Interestingly, individuals living at higher altitudes have a lower fasting glycemia and better glucose tolerance compared with those who live near sea level. There is also emerging evidence of the lower prevalence of both obesity and diabetes at higher altitudes. The mechanisms underlying improved glucose control at higher altitudes remain unclear. In this review, we present the most current evidence about glucose homeostasis in residents living above 1500 m and discuss possible mechanisms that could explain the lower fasting glycemia and lower prevalence of obesity and diabetes in this population. Understanding the mechanisms that regulate and maintain the lower fasting glycemia in individuals who live at higher altitudes could lead to new therapeutics for impaired glucose homeostasis. PMID:25675133

  10. High Altitude Clear Air Turbulence Project

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Air Force Flight Dynamics Laboratory conducted the High Altitude Clear Air Turbulence Project in the mid 1960s with the intention of better understanding air...

  11. Hemorrhages and hemostasis in guinea-pigs exposed to irradiation at high altitude

    International Nuclear Information System (INIS)

    Tartakovskij, V.N.; Daniyarov, S.B.

    1988-01-01

    Hemorrhagic intensity, hemostasis and blood vessel wall resistance to mechanical effects were studied in guinea-pigs exposed to whole-body irradiation (3.0 Gy). The animals were irradiated at low altitude (760 m above sea level) and at high altitude (3200 m above sea level) after 1 and 31 days of adaptation. It was demonstrated that hemorrhagic intensity in both groups of guinea-pigs irradiated at high altitude was significantly reduced in comparison with that at low altitude. The decrease of radiation-induced hemorrhages at high altitude is associated with less severe changes in thrombopoiesis, blood vessel wall and blood coagulation

  12. Mechanisms of Memory Dysfunction during High Altitude Hypoxia Training in Military Aircrew.

    Science.gov (United States)

    Nation, Daniel A; Bondi, Mark W; Gayles, Ellis; Delis, Dean C

    2017-01-01

    Cognitive dysfunction from high altitude exposure is a major cause of civilian and military air disasters. Pilot training improves recognition of the early symptoms of altitude exposure so that countermeasures may be taken before loss of consciousness. Little is known regarding the nature of cognitive impairments manifesting within this critical window when life-saving measures may still be taken. Prior studies evaluating cognition during high altitude simulation have predominantly focused on measures of reaction time and other basic attention or motor processes. Memory encoding, retention, and retrieval represent critical cognitive functions that may be vulnerable to acute hypoxic/ischemic events and could play a major role in survival of air emergencies, yet these processes have not been studied in the context of high altitude simulation training. In a series of experiments, military aircrew underwent neuropsychological testing before, during, and after brief (15 min) exposure to high altitude simulation (20,000 ft) in a pressure-controlled chamber. Acute exposure to high altitude simulation caused rapid impairment in learning and memory with relative preservation of basic visual and auditory attention. Memory dysfunction was predominantly characterized by deficiencies in memory encoding, as memory for information learned during high altitude exposure did not improve after washout at sea level. Retrieval and retention of memories learned shortly before altitude exposure were also impaired, suggesting further impairment in memory retention. Deficits in memory encoding and retention are rapidly induced upon exposure to high altitude, an effect that could impact life-saving situational awareness and response. (JINS, 2017, 23, 1-10).

  13. Isotopic signatures for natural versus anthropogenic Pb in high-altitude Mt. Everest ice cores during the past 800 years

    International Nuclear Information System (INIS)

    Lee, Khanghyun; Hur, Soon Do; Hou, Shugui; Burn-Nunes, Laurie J.; Hong, Sungmin; Barbante, Carlo; Boutron, Claude F.; Rosman, Kevin J.R.

    2011-01-01

    A long-term record, extending back 800 years (1205 to 2002 AD), of the Pb isotopic composition ( 206 Pb/ 207 Pb and 208 Pb/ 207 Pb) as well as Pb concentrations from high altitude Mt. Everest ice cores has the potential to identify sources and source regions affecting natural and anthropogenic Pb deposition in central Asia. The results show that the regional natural background Pb isotope signature (∼ 1.20 for 206 Pb/ 207 Pb and ∼ 2.50 for 208 Pb/ 207 Pb) in the central Himalayas was dominated by mineral dust over the last ∼ 750 years from 1205 to 1960s, mostly originating from local sources with occasional contributions of long-range transported dust probably from Sahara desert and northwestern India. Since the 1970s, the Pb isotope ratios are characterized by a continuous decline toward less radiogenic ratios with the least mean ratios of 1.178 for 206 Pb/ 207 Pb and 2.471 for 208 Pb/ 207 Pb in the period 1990–1996. The depression of the 206 Pb/ 207 Pb and 208 Pb/ 207 Pb values during the corresponding periods is most likely due to an increasing influence of less radiogenic Pb of anthropogenic origin mainly from leaded gasoline used in South Asia (India as well as possibly Bangladesh and Nepal). From 1997 to 2002, isotopic composition tends to show a shift to slightly more radiogenic signature. This is likely attributed to reducing Pb emissions from leaded gasoline in source regions, coinciding with the nationwide reduction of Pb in gasoline and subsequent phase-out of leaded gasoline in South Asia since 1997. An interesting feature is the relatively high levels of Pb concentrations and enrichment factors (EF) between 1997 and 2002. Although the reason for this feature remains uncertain, it would be probably linked with an increasing influence of anthropogenic Pb emitted from other sources such as fossil fuel combustion and non-ferrous metal production.

  14. Isotopic signatures for natural versus anthropogenic Pb in high-altitude Mt. Everest ice cores during the past 800 years

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Khanghyun; Hur, Soon Do [Korea Polar Research Institute, Songdo Techno Park, 7-50, Songdo-dong, Yeonsu-gu, Incheon 406-840 (Korea, Republic of); Hou, Shugui [State Key Laboratory of Cryospheric Science, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Science, Lanzhou 730000 (China); School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210093 (China); Burn-Nunes, Laurie J. [Department of Imaging and Applied Physics, Curtin University of Technology, GPO Box U1987, Perth, WA 6845 (Australia); Hong, Sungmin, E-mail: smhong@inha.ac.kr [Department of Ocean Sciences, Inha University, 253 Yonghyun-dong, Nam-gu, Incheon, 402-751 (Korea, Republic of); Barbante, Carlo [Department of Environmental Sciences, University Ca' Foscari of Venice, Dorsoduro 2137, 30 123 Venice (Italy); Institute for the Dynamics of Environmental Processes-CNR, University Ca' Foscari of Venice, Dorsoduro 2137, 30 123 Venice (Italy); Boutron, Claude F. [Laboratoire de Glaciologie et Geophysique de l' Environnement (UMR Universite Joseph Fourier/CNRS 5183 ), 54 rue Moliere, BP 96, 38402 Saint Martin d' Heres Cedex (France); Unite de Formation et de Recherche ' Physique, Ingenierie, Terre, Environnement, Mecanique' , Universite Joseph Fourier de Grenoble ( Institut Universitaire de France ), 715 rue de la Houille Blanche, BP 53, 38041 Grenoble Cedex 9 (France); Rosman, Kevin J.R. [Department of Imaging and Applied Physics, Curtin University of Technology, GPO Box U1987, Perth, WA 6845 (Australia)

    2011-12-15

    A long-term record, extending back 800 years (1205 to 2002 AD), of the Pb isotopic composition ({sup 206}Pb/{sup 207}Pb and {sup 208}Pb/{sup 207}Pb) as well as Pb concentrations from high altitude Mt. Everest ice cores has the potential to identify sources and source regions affecting natural and anthropogenic Pb deposition in central Asia. The results show that the regional natural background Pb isotope signature ({approx} 1.20 for {sup 206}Pb/{sup 207}Pb and {approx} 2.50 for {sup 208}Pb/{sup 207}Pb) in the central Himalayas was dominated by mineral dust over the last {approx} 750 years from 1205 to 1960s, mostly originating from local sources with occasional contributions of long-range transported dust probably from Sahara desert and northwestern India. Since the 1970s, the Pb isotope ratios are characterized by a continuous decline toward less radiogenic ratios with the least mean ratios of 1.178 for {sup 206}Pb/{sup 207}Pb and 2.471 for {sup 208}Pb/{sup 207}Pb in the period 1990-1996. The depression of the {sup 206}Pb/{sup 207}Pb and {sup 208}Pb/{sup 207}Pb values during the corresponding periods is most likely due to an increasing influence of less radiogenic Pb of anthropogenic origin mainly from leaded gasoline used in South Asia (India as well as possibly Bangladesh and Nepal). From 1997 to 2002, isotopic composition tends to show a shift to slightly more radiogenic signature. This is likely attributed to reducing Pb emissions from leaded gasoline in source regions, coinciding with the nationwide reduction of Pb in gasoline and subsequent phase-out of leaded gasoline in South Asia since 1997. An interesting feature is the relatively high levels of Pb concentrations and enrichment factors (EF) between 1997 and 2002. Although the reason for this feature remains uncertain, it would be probably linked with an increasing influence of anthropogenic Pb emitted from other sources such as fossil fuel combustion and non-ferrous metal production.

  15. High altitude medicine education in China: exploring a new medical education reform.

    Science.gov (United States)

    Luo, Yongjun; Luo, Rong; Li, Weiming; Huang, Jianjun; Zhou, Qiquan; Gao, Yuqi

    2012-03-01

    China has the largest plateau in the world, which includes the whole of Tibet, part of Qinghai, Xinjiang, Yunnan, and Sichuan. The plateau area is about 257.2×10(4) km(2), which accounts for about 26.8% of the total area of China. According to data collected in 2006, approximately twelve million people were living at high altitudes, between 2200 to 5200 m high, on the Qinghai-Tibetan Plateau. Therefore, there is a need for medical workers who are trained to treat individuals living at high altitudes. To train undergraduates in high altitude medicine, the College of High Altitude Military Medicine was set up at the Third Military Medical University (TMMU) in Chongqing in 1999. This is the only school to teach high altitude medicine in China. Students at TMMU study natural and social sciences, basic medical sciences, clinical medical sciences, and high altitude medicine. In their 5(th) year, students work as interns at the General Hospital of Tibet Military Command in Lhasa for 3 months, where they receive on-site teaching. The method of on-site teaching is an innovative approach for training in high altitude medicine for undergraduates. Three improvements were implemented during the on-site teaching component of the training program: (1) standardization of the learning progress; (2) integration of formal knowledge with clinical experience; and (3) coaching students to develop habits of inquiry and to engage in ongoing self-improvement to set the stage for lifelong learning. Since the establishment of the innovative training methods in 2001, six classes of high altitude medicine undergraduates, who received on-site teaching, have graduated and achieved encouraging results. This evidence shows that on-site teaching needs to be used more widely in high altitude medicine education.

  16. Accuracy of Handheld Blood Glucose Meters at High Altitude

    NARCIS (Netherlands)

    de Mol, Pieter; Krabbe, Hans G.; de Vries, Suzanna T.; Fokkert, Marion J.; Dikkeschei, Bert D.; Rienks, Rienk; Bilo, Karin M.; Bilo, Henk J. G.

    2010-01-01

    Background: Due to increasing numbers of people with diabetes taking part in extreme sports (e. g., high-altitude trekking), reliable handheld blood glucose meters (BGMs) are necessary. Accurate blood glucose measurement under extreme conditions is paramount for safe recreation at altitude. Prior

  17. Thermodynamics of high-pressure ice polymorphs : ices III and V

    NARCIS (Netherlands)

    Tchijov, [No Value; Ayala, RB; Leon, GC; Nagornov, O

    Thermodynamic properties of high-pressure ice polymorphs, ices III and V, are studied theoretically. The results of TIP4P molecular dynamics simulations in the NPT ensemble are used to calculate the temperature dependence of the specific volume of ices III and V at pressures 0.25 and 0.5 GPa,

  18. Outdoor Activity and High Altitude Exposure During Pregnancy: A Survey of 459 Pregnancies.

    Science.gov (United States)

    Keyes, Linda E; Hackett, Peter H; Luks, Andrew M

    2016-06-01

    To evaluate whether women engage in outdoor activities and high altitude travel during pregnancy; the health care advice received regarding high altitude during pregnancy; and the association between high altitude exposure and self-reported pregnancy complications. An online survey of women with at least 1 pregnancy distributed on websites and e-mail lists targeting mothers and/or mountain activities. Outcome measures were outdoor activities during pregnancy, high altitude (>2440 m) exposure during pregnancy, and pregnancy and perinatal complications. Hiking, running, and swimming were the most common activities performed during pregnancy. Women traveled to high altitude in over half of the pregnancies (244/459), and most did not receive counseling regarding altitude (355, 77%), although a small proportion (14, 3%) were told not to go above 2440 m. Rates of miscarriage and most other complications were similar between pregnancies with and without travel above 2440 m. Pregnancies with high altitude exposure were more likely to have preterm labor (odds ratio [OR] 2.3; 95% CI 0.97-5.4; P = .05). Babies born to women who went to high altitude during pregnancy were more likely to need oxygen at birth (OR 2.34; 95% CI 1.04-5.26; P sports and travel to high altitude have a low rate of complications. Given the limitations of our data, further research is necessary on the risks associated with high altitude travel and physical activity and how these apply to the general population. Copyright © 2016 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

  19. HIGH ALTITUDES EFFECTS ON HEMATOLOGIC BLOOD PARAMETERS

    Directory of Open Access Journals (Sweden)

    Hasim Rushiti

    2015-05-01

    Full Text Available The approach and the objective of this experiment are consistent with the determination of changes of blood parameters after the stay of the students at an altitude of 1800-2300 meters, for a ten-day long ski course. In this paper are included a total of 64 students of the Faculty of Sport Sciences in Prishtina, of the age group of 19-25 (the average age is 21. All students previously have undergone a medical check for TA, arterial pulse and respiratory rate. In particular, the health situation is of subjects was examined, then, all students, at the same time, gave blood for analysis. In this experiment, three main hematologic parameters were taken in consideration: such as hemoglobin, hematocrit and red blood cells. The same analyses were carried out after the 10-day stay at a high altitude. The results of the experiment have shown significant changes after the ten-day stay at high altitude, despite the previous results that show changes only after the twenty-day stay in such elevations.

  20. [Physiological aspects of altitude training and the use of altitude simulators].

    Science.gov (United States)

    Ranković, Goran; Radovanović, Dragan

    2005-01-01

    Altitude training in various forms is widely practiced by athletes and coaches in an attempt to improve sea level endurance. Training at high altitude may improve performance at sea level through altitude acclimatisation, which improves oxygen transport and/or utilisation, or through hypoxia, which intensifies the training stimulus. This basic physiological aspect allows three training modalities: live high and train high (classic high-altitude training), live low and train high (training through hypoxia), and live high and train low (the new trend). In an effort to reduce the financial and logistical challenges of travelling to high-altitude training sites, scientists and manufactures have developed artificial high-altitude environments, which simulate the hypoxic conditions of moderate altitude (2000-3000 meters). Endurance athletes from many sports have recently started using nitrogen environments, or hypoxic rooms and tents as part of their altitude training programmes. The results of controlled studies on these modalities of high-altitude training, their practical approach, and ethics are summarised.

  1. Physiological aspects of altitude training and the use of altitude simulators

    Directory of Open Access Journals (Sweden)

    Ranković Goran

    2005-01-01

    Full Text Available Altitude training in various forms is widely practiced by athletes and coaches in an attempt to improve sea level endurance. Training at high altitude may improve performance at sea level through altitude acclimatization, which improves oxygen transport and/or utilization, or through hypoxia, which intensifies the training stimulus. This basic physiological aspect allows three training modalities: live high and train high (classic high-altitude training, live low and train high (training through hypoxia, and live high and train low (the new trend. In an effort to reduce the financial and logistical challenges of traveling to high-altitude training sites, scientists and manufactures have developed artificial high-altitude environments, which simulate the hypoxic conditions of moderate altitude (2000-3000 meters. Endurance athletes from many sports have recently started using nitrogen environments, or hypoxic rooms and tents as part of their altitude training programmes. The results of controlled studies on these modalities of high-altitude training, their practical approach, and ethics are summarized.

  2. Low-resolution ship detection from high-altitude aerial images

    Science.gov (United States)

    Qi, Shengxiang; Wu, Jianmin; Zhou, Qing; Kang, Minyang

    2018-02-01

    Ship detection from optical images taken by high-altitude aircrafts such as unmanned long-endurance airships and unmanned aerial vehicles has broad applications in marine fishery management, ship monitoring and vessel salvage. However, the major challenge is the limited capability of information processing on unmanned high-altitude platforms. Furthermore, in order to guarantee the wide detection range, unmanned aircrafts generally cruise at high altitudes, resulting in imagery with low-resolution targets and strong clutters suffered by heavy clouds. In this paper, we propose a low-resolution ship detection method to extract ships from these high-altitude optical images. Inspired by a recent research on visual saliency detection indicating that small salient signals could be well detected by a gradient enhancement operation combined with Gaussian smoothing, we propose the facet kernel filtering to rapidly suppress cluttered backgrounds and delineate candidate target regions from the sea surface. Then, the principal component analysis (PCA) is used to compute the orientation of the target axis, followed by a simplified histogram of oriented gradient (HOG) descriptor to characterize the ship shape property. Finally, support vector machine (SVM) is applied to discriminate real targets and false alarms. Experimental results show that the proposed method actually has high efficiency in low-resolution ship detection.

  3. Fatalities in high altitude mountaineering: a review of quantitative risk estimates.

    Science.gov (United States)

    Weinbruch, Stephan; Nordby, Karl-Christian

    2013-12-01

    Quantitative estimates for mortality in high altitude mountaineering are reviewed. Special emphasis is placed on the heterogeneity of the risk estimates and on confounding. Crude estimates for mortality are on the order of 1/1000 to 40/1000 persons above base camp, for both expedition members and high altitude porters. High altitude porters have mostly a lower risk than expedition members (risk ratio for all Nepalese peaks requiring an expedition permit: 0.73; 95 % confidence interval 0.59-0.89). The summit bid is generally the most dangerous part of an expedition for members, whereas most high altitude porters die during route preparation. On 8000 m peaks, the mortality during descent from summit varies between 4/1000 and 134/1000 summiteers (members plus porters). The risk estimates are confounded by human and environmental factors. Information on confounding by gender and age is contradictory and requires further work. There are indications for safety segregation of men and women, with women being more risk averse than men. Citizenship appears to be a significant confounder. Prior high altitude mountaineering experience in Nepal has no protective effect. Commercial expeditions in the Nepalese Himalayas have a lower mortality than traditional expeditions, though after controlling for confounding, the difference is not statistically significant. The overall mortality is increasing with increasing peak altitude for expedition members but not for high altitude porters. In the Nepalese Himalayas and in Alaska, a significant decrease of mortality with calendar year was observed. A few suggestions for further work are made at the end of the article.

  4. Increased insulin requirements during exercise at very high altitude in type 1 diabetes

    NARCIS (Netherlands)

    de Mol, Pieter; de Vries, Suzanna T.; de Koning, Eelco J. P.; Gans, Rijk O. B.; Tack, Cees J.; Bilo, Henk J. G.

    OBJECTIVE-Safe, very high altitude trekking in subjects with type 1 diabetes requires understanding of glucose regulation at high altitude. We investigated insulin requirements, energy expenditure, and glucose levels at very high altitude in relation to acute mountain sickness (AMS) symptoms in

  5. Mitochondrial function in human skeletal muscle following high-altitude exposure

    DEFF Research Database (Denmark)

    Jacobs, Robert A; Boushel, Robert; Wright-Paradis, Cynthia

    2013-01-01

    Studies regarding mitochondrial modifications in human skeletal muscle following acclimatization to high altitude are conflicting, and these inconsistencies may be due to the prevalence of representing mitochondrial function through static and isolated measurements of specific mitochondrial...... characteristics. The aim of this study, therefore, was to investigate mitochondrial function in response to high-altitude acclimatization through measurements of respiratory control in the vastus lateralis muscle. Skeletal muscle biopsies were obtained from 10 lowland natives prior to and again after a total of 9......-11 days of exposure to 4559 m. High-resolution respirometry was performed on the muscle samples to compare respiratory chain function and respiratory capacities. Respirometric analysis revealed that mitochondrial function was largely unaffected, because high-altitude exposure did not affect the capacity...

  6. Recently deglaciated high-altitude soils of the Himalaya: diverse environments, heterogenous bacterial communities and long-range dust inputs from the upper troposphere.

    Directory of Open Access Journals (Sweden)

    Blaz Stres

    Full Text Available The Himalaya with its altitude and geographical position forms a barrier to atmospheric transport, which produces much aqueous-particle monsoon precipitation and makes it the largest continuous ice-covered area outside polar regions. There is a paucity of data on high-altitude microbial communities, their native environments and responses to environmental-spatial variables relative to seasonal and deglaciation events.Soils were sampled along altitude transects from 5000 m to 6000 m to determine environmental, spatial and seasonal factors structuring bacterial communities characterized by 16 S rRNA gene deep sequencing. Dust traps and fresh-snow samples were used to assess dust abundance and viability, community structure and abundance of dust associated microbial communities. Significantly different habitats among the altitude-transect samples corresponded to both phylogenetically distant and closely-related communities at distances as short as 50 m showing high community spatial divergence. High within-group variability that was related to an order of magnitude higher dust deposition obscured seasonal and temporal rearrangements in microbial communities. Although dust particle and associated cell deposition rates were highly correlated, seasonal dust communities of bacteria were distinct and differed significantly from recipient soil communities. Analysis of closest relatives to dust OTUs, HYSPLIT back-calculation of airmass trajectories and small dust particle size (4-12 µm suggested that the deposited dust and microbes came from distant continental, lacustrine and marine sources, e.g. Sahara, India, Caspian Sea and Tibetan plateau. Cyanobacteria represented less than 0.5% of microbial communities suggesting that the microbial communities benefitted from (codeposited carbon which was reflected in the psychrotolerant nature of dust-particle associated bacteria.The spatial, environmental and temporal complexity of the high-altitude soils of the

  7. Recently deglaciated high-altitude soils of the Himalaya: diverse environments, heterogenous bacterial communities and long-range dust inputs from the upper troposphere.

    Science.gov (United States)

    Stres, Blaz; Sul, Woo Jun; Murovec, Bostjan; Tiedje, James M

    2013-01-01

    The Himalaya with its altitude and geographical position forms a barrier to atmospheric transport, which produces much aqueous-particle monsoon precipitation and makes it the largest continuous ice-covered area outside polar regions. There is a paucity of data on high-altitude microbial communities, their native environments and responses to environmental-spatial variables relative to seasonal and deglaciation events. Soils were sampled along altitude transects from 5000 m to 6000 m to determine environmental, spatial and seasonal factors structuring bacterial communities characterized by 16 S rRNA gene deep sequencing. Dust traps and fresh-snow samples were used to assess dust abundance and viability, community structure and abundance of dust associated microbial communities. Significantly different habitats among the altitude-transect samples corresponded to both phylogenetically distant and closely-related communities at distances as short as 50 m showing high community spatial divergence. High within-group variability that was related to an order of magnitude higher dust deposition obscured seasonal and temporal rearrangements in microbial communities. Although dust particle and associated cell deposition rates were highly correlated, seasonal dust communities of bacteria were distinct and differed significantly from recipient soil communities. Analysis of closest relatives to dust OTUs, HYSPLIT back-calculation of airmass trajectories and small dust particle size (4-12 µm) suggested that the deposited dust and microbes came from distant continental, lacustrine and marine sources, e.g. Sahara, India, Caspian Sea and Tibetan plateau. Cyanobacteria represented less than 0.5% of microbial communities suggesting that the microbial communities benefitted from (co)deposited carbon which was reflected in the psychrotolerant nature of dust-particle associated bacteria. The spatial, environmental and temporal complexity of the high-altitude soils of the Himalaya

  8. Correlating Ice Cores from Quelccaya Ice Cap with Chronology from Little Ice Age Glacial Extents

    Science.gov (United States)

    Stroup, J. S.; Kelly, M. A.; Lowell, T. V.

    2010-12-01

    Proxy records indicate Southern Hemisphere climatic changes during the Little Ice Age (LIA; ~1300-1850 AD). In particular, records of change in and around the tropical latitudes require attention because these areas are sensitive to climatic change and record the dynamic interplay between hemispheres (Oerlemans, 2005). Despite this significance, relatively few records exist for the southern tropics. Here we present a reconstruction of glacial fluctuations of Quelccaya Ice Cap (QIC), Peruvian Andes, from pre-LIA up to the present day. In the Qori Kalis valley, extensive sets of moraines exist beginning with the 1963 AD ice margin (Thompson et al., 2006) and getting progressively older down valley. Several of these older moraines can be traced and are continuous with moraines in the Challpa Cocha valley. These moraines have been dated at chronology of past ice cap extents are correlated with ice core records from QIC which show an accumulation increase during ~1500-1700 AD and an accumulation decrease during ~1720-1860 AD (Thompson et al., 1985; 1986; 2006). In addition, other proxy records from Peru and the tropics are correlated with the records at QIC as a means to understand climate conditions during the LIA. This work forms the basis for future modeling of the glacial system during the LIA at QIC and for modeling of past temperature and precipitation regimes at high altitude in the tropics.

  9. Stratospheric effects on trends of mesospheric ice clouds (Invited)

    Science.gov (United States)

    Luebken, F.; Baumgarten, G.; Berger, U.

    2009-12-01

    Ice layers in the summer mesosphere at middle and polar latitudes appear as `noctilucent clouds' (NLC) and `polar mesosphere clouds'(PMC) when observed by optical methods from the ground or from satellites, respectively. A newly developed model of the atmosphere called LIMA (Leibniz Institute Middle Atmosphere Model) nicely reproduces the mean conditions of the summer mesopause region and is used to study the ice layer morphology (LIMA/ice). LIMA nudges to ECMWF data in the troposphere and lower stratosphere which influences the background conditions in the mesosphere and ice cloud morphology. Since ice layer formation is very sensitive to the thermal structure of the mesopause region the morphology of NLC and PMC is frequently discussed in terms of long term variations. Model runs of LIMA/ice are now available for 1961 until 2008. A strong correlation between temperatures and PMC altitudes is observed. Applied to historical measurements this gives negligible temperature trends at PMC altitudes (approximately 0.01-0.02 K/y). Trace gas concentrations are kept constant in LIMA except for water vapor which is modified by variable solar radiation. Still, long term trends in temperatures and ice layer parameters are observed, consistent with observations. We present results regarding inter-annual variability of upper mesosphere temperatures, water vapor, and ice clouds, and also long term variations. We compare our model results with satellite borne and lidar observations including some record high NLC parameters measured in the summer season of 2009. The latitudinal dependence of trends and ice layer parameters is discussed, including a NH/SH comparison. We will present an explanation of the trends in the background atmosphere and ice layer parameters.

  10. Seasonal variations in the sources of natural and anthropogenic lead deposited at the East Rongbuk Glacier in the high-altitude Himalayas.

    Science.gov (United States)

    Burn-Nunes, Laurie; Vallelonga, Paul; Lee, Khanghyun; Hong, Sungmin; Burton, Graeme; Hou, Shugui; Moy, Andrew; Edwards, Ross; Loss, Robert; Rosman, Kevin

    2014-07-15

    Lead (Pb) isotopic compositions and concentrations, and barium (Ba) and indium (In) concentrations have been analysed at sub-annual resolution in three sections from a snow pit samples dated to 2004/2005, recovered from the East Rongbuk Glacier in the high-altitude Himalayas. Ice core sections indicate that atmospheric chemistry prior to ~1,953 was controlled by mineral dust inputs, with no discernible volcanic or anthropogenic contributions. Eighteenth century monsoon ice core chemistry is indicative of dominant contributions from local Himalayan sources; non-monsoon ice core chemistry is linked to contributions from local (Himalayan), regional (Indian/Thar Desert) and long-range (North Africa, Central Asia) sources. Twentieth century monsoon and non-monsoon ice core data demonstrate similar seasonal sources of mineral dust, however with a transition to less-radiogenic isotopic signatures that suggests local and regional climate/environmental change. The snow pit record demonstrates natural and anthropogenic contributions during both seasons, with increased anthropogenic influence during non-monsoon times. Monsoon anthropogenic inputs are most likely sourced to South/South-East Asia and/or India, whereas non-monsoon anthropogenic inputs are most likely sourced to India and Central Asia. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Reduced oxygen at high altitude limits maximum size.

    Science.gov (United States)

    Peck, L S; Chapelle, G

    2003-11-07

    The trend towards large size in marine animals with latitude, and the existence of giant marine species in polar regions have long been recognized, but remained enigmatic until a recent study showed it to be an effect of increased oxygen availability in sea water of a low temperature. The effect was apparent in data from 12 sites worldwide because of variations in water oxygen content controlled by differences in temperature and salinity. Another major physical factor affecting oxygen content in aquatic environments is reduced pressure at high altitude. Suitable data from high-altitude sites are very scarce. However, an exceptionally rich crustacean collection, which remains largely undescribed, was obtained by the British 1937 expedition from Lake Titicaca on the border between Peru and Bolivia in the Andes at an altitude of 3809 m. We show that in Lake Titicaca the maximum length of amphipods is 2-4 times smaller than other low-salinity sites (Caspian Sea and Lake Baikal).

  12. Characterizing Arctic Sea Ice Topography Using High-Resolution IceBridge Data

    Science.gov (United States)

    Petty, Alek; Tsamados, Michel; Kurtz, Nathan; Farrell, Sinead; Newman, Thomas; Harbeck, Jeremy; Feltham, Daniel; Richter-Menge, Jackie

    2016-01-01

    We present an analysis of Arctic sea ice topography using high resolution, three-dimensional, surface elevation data from the Airborne Topographic Mapper, flown as part of NASA's Operation IceBridge mission. Surface features in the sea ice cover are detected using a newly developed surface feature picking algorithm. We derive information regarding the height, volume and geometry of surface features from 2009-2014 within the Beaufort/Chukchi and Central Arctic regions. The results are delineated by ice type to estimate the topographic variability across first-year and multi-year ice regimes.

  13. High-altitude haematology: Quechua-Aymara comparisons.

    Science.gov (United States)

    Arnaud, J; Quilici, J C; Rivière, G

    1981-01-01

    Haematological studies have been carried out at various altitudes between 450 m and 4800 m, on two separate human groups (Quechuas and Aymaras) living in South America. Changes in the haematological parameters do not develop linearly in relation to the attitude. Th impact of chronic hypoxia on erythropoiesis is greater above 3000 m. The haemogram varies quantitatively and not qualitatively (mean corpuscular volume and mean haemoglobin concentration remain constant). The haematological study also reveals the greater adaptability to high altitude of the Aymaras, an adaptability characterized by an increase in red cell count and concentration and a decrease in red cell volume. The adaptative phenomena observed in the Quechuas are reversible, whereas they persist in the Aymaras when they migrate to the lowlands (450 m).

  14. The radiation protection problems of high altitude and space flight

    International Nuclear Information System (INIS)

    Fry, R.J.M.

    1993-01-01

    This paper considers the radiation environment in aircraft at high altitudes and spacecraft in low earth orbit and in deep space and the factors that influence the dose equivalents. Altitude, latitude and solar cycle are the major influences for flights below the radiation belts. In deep space, solar cycle and the occurrence of solar particle events are the factors of influence. The major radiation effects of concern are cancer and infertility in males. In high altitude aircraft the radiation consists mainly of protons and neutrons, with neutrons contributing about half the equivalent dose. The average dose rate at altitudes of transcontinental flights that approach the polar regions are greater by a factor of about 2.5 than on routes at low latitudes. Current estimates of does to air crews suggest they are well within the ICRP (1990) recommended dose limits for radiation workers

  15. Risk Stratification for Athletes and Adventurers in High-Altitude Environments: Recommendations for Preparticipation Evaluation.

    Science.gov (United States)

    Campbell, Aaron D; McIntosh, Scott E; Nyberg, Andy; Powell, Amy P; Schoene, Robert B; Hackett, Peter

    2015-12-01

    High-altitude athletes and adventurers face a number of environmental and medical risks. Clinicians often advise participants or guiding agencies before or during these experiences. Preparticipation evaluation (PPE) has the potential to reduce risk of high-altitude illnesses in athletes and adventurers. Specific conditions susceptible to high-altitude exacerbation also important to evaluate include cardiovascular and lung diseases. Recommendations by which to counsel individuals before participation in altitude sports and adventures are few and of limited focus. We reviewed the literature, collected expert opinion, and augmented principles of a traditional sport PPE to accommodate the high-altitude wilderness athlete/adventurer. We present our findings with specific recommendations on risk stratification during a PPE for the high-altitude athlete/adventurer. Copyright © 2015. Published by Elsevier Inc.

  16. Nasal variation in relation to high-altitude adaptations among Tibetans and Andeans.

    Science.gov (United States)

    Butaric, Lauren N; Klocke, Ross P

    2018-05-01

    High-altitude (>2500 m) populations face several pressures, including hypoxia and cold-dry air, resulting in greater respiratory demand to obtain more oxygen and condition inspired air. While cardiovascular and pulmonary adaptations to high-altitude hypoxia have been extensively studied, adaptations of upper-respiratory structures, e.g., nasal cavity, remain untested. This study investigates whether nasal morphology presents adaptations to hypoxic (larger noses) and/or cold-dry (tall/narrow noses) conditions among high-altitude samples. CT scans of two high- and four low-altitude samples from diverse climates were collected (n = 130): high-altitude Tibetans and Peruvians; low-altitude Peruvians, Southern Chinese (temperate), Mongolian-Buriats (cold-dry), and Southeast Asians (hot-wet). Facial and nasal distances were calculated from 3D landmarks placed on digitally-modeled crania. Temperature, precipitation, and barometric pressure data were also obtained. Principal components analysis and analyses of variance primarily indicate size-related differences among the cold-dry (Mongolian-Buriats) and hot-wet (Southeast Asians) adapted groups. Two-block partial least squares (PLS) analysis show weak relationships between size-standardized nasal dimensions and environmental variables. However, among PLS1 (85.90% of covariance), Tibetans display relatively larger nasal cavities related to lower temperatures and barometric pressure; regression analyses also indicate high-altitude Tibetans possess relatively larger internal nasal breadths and heights for their facial size. Overall, nasal differences relate to climate among the cold-dry and hot-wet groups. Specific nasal adaptations were not identified among either Peruvian group, perhaps due to their relatively recent migration history and population structure. However, high-altitude Tibetans seem to exhibit a compromise in nasal morphology, serving in increased oxygen uptake, and air-conditioning processes. © 2018

  17. Mast cells in the human lung at high altitude

    Science.gov (United States)

    Heath, Donald

    1992-12-01

    Mast cell densities in the lung were measured in five native highlanders of La Paz (3600 m) and in one lowlander dying from high-altitude pulmonary oedema (HAPO) at 3440 m. Two of the highlanders were mestizos with normal pulmonary arteries and the others were Aymara Indians with muscular remodelling of their pulmonary vasculature. The aim of the investigation was to determine if accumulation of mast cells in the lung at high altitude (HA) is related to alveolar hypoxia alone, to a combination of hypoxia and muscularization of the pulmonary arterial tree, or to oedema of the lung. The lungs of four lowlanders were used as normoxic controls. The results showed that the mast cell density of the two Mestizos was in the normal range of lowlanders (0.6-8.8 cells/mm2). In the Aymara Indians the mast cell counts were raised (25.6-26.0 cells/mm2). In the lowlander dying from HAPO the mast cell count was greatly raised to 70.1 cells/mm2 lung tissue. The results show that in native highlanders an accumulation of mast cells in the lung is not related to hypoxia alone but to a combination of hypoxia and muscular remodelling of the pulmonary arteries. However, the most potent cause of increased mast cell density in the lung at high altitude appears to be high-altitude pulmonary oedema.

  18. Air Quality Standards for Particulate Matter (PM) at high altitude cities

    International Nuclear Information System (INIS)

    Bravo Alvarez, H.; Sosa Echeverria, R.; Sanchez Alvarez, P.; Krupa, S.

    2013-01-01

    The Air Quality Standards for Particulate Matter (PM) at high altitude urban areas in different countries, must consider the pressure and temperature due to the effect that these parameters have on the breath volume. This paper shows the importance to correct Air Quality Standards for PM considering pressure and temperature at different altitudes. Specific factors were suggested to convert the information concerning PM, from local to standard conditions, and adjust the Air Quality Standards for different high altitudes cities. The correction factors ranged from: 1.03 for Santiago de Chile to 1.47 for El Alto Bolivia. Other cities in this study include: Mexico City, México; La Paz, Bolivia; Bogota, Cali and Medellin, Colombia; Quito, Ecuador and Cuzco, Peru. If these corrections are not considered, the atmospheric concentrations will be underestimated. - Highlights: ► AQS for particulate matter concentrations adjusted by pressure and temperature. ► Particulate matter concentrations can be underestimated in high altitude Cities. ► Particulate matter concentrations must be compared under the same conditions. - In order to compare high altitude atmospheric PM concentrations with AQS, one must consider T and P of the sampling site.

  19. Circulatory adaptation to long-term high altitude exposure in Aymaras and Caucasians.

    Science.gov (United States)

    Stuber, Thomas; Scherrer, Urs

    2010-01-01

    About 30 million people live above 2500 m in the Andean Mountains of South America. Among them are 5.5 million Aymaras, an ethnic group with its own language, living on the altiplano of Bolivia, Peru, and northern Chile at altitudes of up to 4400 m. In this high altitude region traces of human population go back for more than 2000 years with constant evolutionary pressure on its residents for genetic adaptation to high altitude. Aymaras as the assumed direct descendents of the ancient cultures living in this region were the focus of much research interest during the last decades and several distinctive adaptation patterns to life at high altitude have been described in this ethnic group. The aim of this article was to review the physiology and pathophysiology of circulatory adaptation and maladaptation to longtime altitude exposure in Aymaras and Caucasians.

  20. High density amorphous ice and its phase transition to ice XII

    International Nuclear Information System (INIS)

    Kohl, I.

    2001-07-01

    1998 Lobban et al. reported the neutron diffraction data of a new phase of ice, called ice XII, which formed at 260 K on compression of water within the domain of ice V at a pressure of 0.5 GPa. Surprisingly ice XII forms as an incidental product in the preparation of high-density amorphous ice (HDA) on compression of hexagonale ice (ice Ih) at 77 K up to pressures = 1.3 GPa. A decisive experimental detail is the use of an indium container: when compressing ice Ih in a pressure vessel with indium linings, then reproducibly HDA (high density amorphous ice) forms, but without indium randomly scattered relative amounts of ice XII and HDA form. Ice XII forms on compression of ice Ih at 77 K only via HDA, and not directly from ice Ih. Its formation requires a sudden pronounced apparent pressure drop of ca 0.18 GPa at pressures ca 1.1 GPa. These apparent pressure drops can be caused by buildup friction between the piston and the pressure vessel and its sudden release on further compression. I propose that shock-waves generated by apparent pressure drops cause transient local heating and that this induces nucleation and crystal growth. A specific reproducible method to prepare ice XII is heating HDA in a pressure vessel with indium linings at constant pressures (or constant volume). The ice XII (meta-)stability domain extends between ca 158 and 212 K from ca 0.7 to ca 1.5 GPa. DSC (differential scanning calorimetry) and x-ray powder diffraction revealed, that on heating at atmospheric pressure ice XII transforms directly into cubic ice (ice Ic) at 154 K (heating rate 10 K min - 1) and not into an amorphous form before transition to ice Ic. The enthalpy of the ice XII - ice Ic transition is -1.21 ± 0.07 kJ mol -1 . An estimation of the Gibbs free energy at atmospheric pressure and about 140 K results that ice XII is thermodynamically more stable than ice VI. In the heating curve of ice XII a reversible endothermic step can be found at the onset temperature (heating rate

  1. Cerebral venous system and anatomical predisposition to high-altitude headache

    NARCIS (Netherlands)

    Wilson, Mark H.; Davagnanam, Indran; Holland, Graeme; Dattani, Raj S.; Tamm, Alexander; Hirani, Shashivadan P.; Kolfschoten, Nicky; Strycharczuk, Lisa; Green, Cathy; Thornton, John S.; Wright, Alex; Edsell, Mark; Kitchen, Neil D.; Sharp, David J.; Ham, Timothy E.; Murray, Andrew; Holloway, Cameron J.; Clarke, Kieran; Grocott, Mike P. W.; Montgomery, Hugh; Imray, Chris; Ahuja, V.; Aref-Adib, G.; Burnham, R.; Chisholm, A.; Clarke, K.; Coates, D.; Coates, M.; Cook, D.; Cox, M.; Dhillon, S.; Dougall, C.; Doyle, P.; Duncan, P.; Edsell, M.; Edwards, L.; Evans, L.; Gardiner, P.; Grocott, M.; Gunning, P.; Hart, N.; Harrington, J.; Harvey, J.; Holloway, C.; Howard, D.; Hurlbut, D.; Imray, C.; Ince, C.; Jonas, M.; van der Kaaij, J.

    2013-01-01

    As inspired oxygen availability falls with ascent to altitude, some individuals develop high-altitude headache (HAH). We postulated that HAH results when hypoxia-associated increases in cerebral blood flow occur in the context of restricted venous drainage, and is worsened when cerebral compliance

  2. Training-dependent cognitive advantage is suppressed at high altitude.

    Science.gov (United States)

    Li, Peng; Zhang, Gang; You, Hai-Yan; Zheng, Ran; Gao, Yu-Qi

    2012-06-25

    Ascent to high altitude is associated with decreases in cognitive function and work performance as a result of hypoxia. Some workers with special jobs typically undergo intensive mental training because they are expected to be agile, stable and error-free in their job performance. The purpose of this study was to determine the risk to cognitive function acquired from training following hypoxic exposure. The results of WHO neurobehavioral core tests battery (WHO-NCTB) and Raven's standard progressive matrices (RSPM) tests of a group of 54 highly trained military operators were compared with those of 51 non-trained ordinary people and were investigated at sea level and on the fifth day after arrival at high altitudes (3900m). Meanwhile, the plasma levels of brain-derived neurotrophic factor (BDNF), interleukin 1β (IL-1β) and vascular endothelial growth factor (VEGF) were examined. The result showed that at sea level, the trained group exhibited significantly better performance on neurobehavioral and RSPM tests. At high altitude, both groups had decreased accuracy in most cognitive tests and took longer to finish them. More importantly, the highly trained subjects showed more substantial declines than the non-trained subjects in visual reaction accuracy, auditory reaction speed, digit symbol scores, ability to report correct dots in a pursuit aiming test and total RSPM scores. This means that the training-dependent cognitive advantages in these areas were suppressed at high altitudes. The above phenomenon maybe associated with decreased BDNF and elevated inflammatory factor during hypoxia, and other mechanisms could not be excluded. Copyright © 2012 Elsevier Inc. All rights reserved.

  3. Are macroinvertebrates in high altitude streams affected by oxygen deficiency?

    DEFF Research Database (Denmark)

    Jacobsen, Dean; Rostgaard, S.; Vásconez, J. J.

    2003-01-01

    1. The solubility of oxygen in water increases with decreasing temperature. This has led to a general perception of cold, high mountain streams as more oxygen rich than warmer lowland streams, and that macroinvertebrates inhabiting high altitude streams have had no need to adapt to critical oxygen...... conditions. However, this fails to take into account that oxygen solubility declines with decreasing atmospheric pressure, which may be of importance at high altitudes. 2. Based on samples of macroinvertebrate benthos and in situ measurements of respiratory oxygen demand of macroinvertebrates in small...... the mean weight-specific respiratory rate of macroinvertebrates declined by only 50%, from 400 to 3800 m. We suggest that this disproportionately large gap between availability and demand of oxygen at high altitudes may imply a potential oxygen deficiency for the fauna, and we discuss how oxygen deficiency...

  4. Hyperbaric oxygen therapy ameliorates acute brain injury after porcine intracerebral hemorrhage at high altitude.

    Science.gov (United States)

    Zhu, Hai-tao; Bian, Chen; Yuan, Ji-chao; Liao, Xiao-jun; Liu, Wei; Zhu, Gang; Feng, Hua; Lin, Jiang-kai

    2015-06-15

    Intracerebral hemorrhage (ICH) at high altitude is not well understood to date. This study investigates the effects of high altitude on ICH, and examines the acute neuroprotection of hyperbaric oxygen (HBO) therapy against high-altitude ICH. Minipigs were placed in a hypobaric chamber for 72 h before the operation. ICH was induced by an infusion of autologous arterial blood (3 ml) into the right basal ganglia. Animals in the high-altitude ICH group received HBO therapy (2.5 ATA for 60 min) 30 min after ICH. Blood gas, blood glucose and brain tissue oxygen partial pressure (PbtO2) were monitored continuously for animals from all groups, as were microdialysis products including glucose, lactate, pyruvate and glutamate in perihematomal tissue from 3 to 12 h post-ICH. High-altitude ICH animals showed significantly lower PbtO2, higher lactate/pyruvate ratio (LPR) and glutamate levels than low-altitude ICH animals. More severe neurological deficits, brain edema and neuronal damage were also observed in high-altitude ICH. After HBO therapy, PbtO2 was significantly increased and LPR and glutamate levels were significantly decreased. Brain edema, neurological deficits and neuronal damage were also ameliorated. The data suggested a more serious disturbance of tissue oxygenation and cerebral metabolism in the acute stage after ICH at high altitude. Early HBO treatment reduced acute brain injury, perhaps through a mechanism involving the amelioration of the derangement of cerebral oxygenation and metabolism following high-altitude ICH.

  5. Cold induced peripheral vasodilation at high altitudes- a field study

    NARCIS (Netherlands)

    Daanen, H.A.M.; Ruiten, H.J.A. van

    2000-01-01

    A significant reduction in cold-induced vasodilation (CIVD) is observed at high altitudes. No agreement is found in the literature about acclimatization effects on CIVD. Two studies were performed to investigate the effect of altitude acclimatization on CIVD. In the first study 13 male subjects

  6. Control of breathing and the circulation in high-altitude mammals and birds.

    Science.gov (United States)

    Ivy, Catherine M; Scott, Graham R

    2015-08-01

    Hypoxia is an unremitting stressor at high altitudes that places a premium on oxygen transport by the respiratory and cardiovascular systems. Phenotypic plasticity and genotypic adaptation at various steps in the O2 cascade could help offset the effects of hypoxia on cellular O2 supply in high-altitude natives. In this review, we will discuss the unique mechanisms by which ventilation, cardiac output, and blood flow are controlled in high-altitude mammals and birds. Acclimatization to high altitudes leads to some changes in respiratory and cardiovascular control that increase O2 transport in hypoxia (e.g., ventilatory acclimatization to hypoxia). However, acclimatization or development in hypoxia can also modify cardiorespiratory control in ways that are maladaptive for O2 transport. Hypoxia responses that arose as short-term solutions to O2 deprivation (e.g., peripheral vasoconstriction) or regional variation in O2 levels in the lungs (i.e., hypoxic pulmonary vasoconstriction) are detrimental at in chronic high-altitude hypoxia. Evolved changes in cardiorespiratory control have arisen in many high-altitude taxa, including increases in effective ventilation, attenuation of hypoxic pulmonary vasoconstriction, and changes in catecholamine sensitivity of the heart and systemic vasculature. Parallel evolution of some of these changes in independent highland lineages supports their adaptive significance. Much less is known about the genomic bases and potential interactive effects of adaptation, acclimatization, developmental plasticity, and trans-generational epigenetic transfer on cardiorespiratory control. Future work to understand these various influences on breathing and circulation in high-altitude natives will help elucidate how complex physiological systems can be pushed to their limits to maintain cellular function in hypoxia. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. EFFECT OF HIGH ALTITUDE ON ERECTILE FUNCTION IN OTHERWISE HEALTHY INDIVIDUALS

    Directory of Open Access Journals (Sweden)

    Usama Bin Zubair

    2016-06-01

    Full Text Available Objective: To determine the effect of high altitude on Erectile function in otherwise healthy individuals and associated socio demographic factors. Study Design: Cross sectional descriptive study. Place and Duration of Study: January 2014 to March 2014 at Goma, Siachin. Material and Methods: One hundred & twenty two married male subjects living at an altitude of more than 15000 feet for more than 3 month and less than one year were included in the study. Erectile dysfunction (ED was assessed using International Index of Erectile Function-5 (IIEF-5. Age, education, smoking, monthly income, any drug intake, altitude, duration of stay and weather conditions were correlated independently with ED. Results: Out of 122, 26 (21.3% had no ED, 18 had mild, 28 (14.8% had mild to moderate, 36(29.5% had moderate and 14 (11.5% had severe ED. Advancing age, low monthly income, smoking, high altitude, cold weather and longer duration of stay had significant association with ED (p-value<0.05 while education and use of any drug were not found significantly associated in our study. Conclusion: This study showed a high prevalence of erectile dysfunction among otherwise healthy individuals when exposed to high altitude. Special attention should be paid on individuals with more age, less income and those working or residing at higher altitudes in peak winter season. Smoking and stay for longer durations should also be discouraged.

  8. Microalgae community of the Huaytire wetland, an Andean high-altitude wetland in Peru Comunidade de microalgas do wetland Huaytire, uma área alagada de alta altitude nos Andes peruanos

    Directory of Open Access Journals (Sweden)

    Gian Salazar-Torres

    2012-09-01

    Full Text Available AIM: The diversity and distribution of microalgae communities in a high-altitude (3,000 to 4,500 m a.s.l Andean wetland, regionally known as bofedal, were examined to assess seasonal and spatial patterns. METHODS: Samples were taken monthly from June to December, 2008 at 13 stations in the Huaytire wetland (16° 54’ S and 70° 20’ W, covering three areas (impacted by urban land use, impacted by camelid pasture, and non-impacted and three climatologically induced periods (ice-covered, ice-melt and ice-free. RESULTS: A total of 52 genera of algae were recorded. Diatoms were the predominant group in abundance and richness. We found a significantly higher abundance during the ice-melting period, when light exposure and runoff were intermediate, in comparison to the ice-covered (low light and flushing and ice-free (high light and low runoff periods. Microalgae abundance was significantly lower in the non-impacted area compared to the sites close to the urban area and to the camelid pastures. Alpha diversity ranged from 8 to 29 genera per sample. High genera exchange was observed throughout the wetland, showing a similar floristic composition (beta diversity = 4%. CONCLUSIONS: We found that diatoms were dominant and adapted to the extreme conditions of the Andean wetland, showing higher abundance during the ice-melt period and in the livestock area. Also, taxa richness was higher in the ice-melt period and in the most-impacted areas.OBJETIVO: A diversidade e distribuição da comunidade de microalgas em uma área alagada nos Andes (3.000 a 4.500 m de altitude, regionalmente conhecido como bofedal, foram examinadas para avaliar seus padrões sazonais e espaciais. MÉTODOS: As amostras foram coletadas, mensalmente, de junho a dezembro de 2008, em 13 estações no bofedal Huaytire (16° 54’ S e 70° 20’ W, abrangendo três áreas (impactada por ação urbana, impactada por pastagem de gado camelídeo e área não impactada e três per

  9. Microalgae community of the Huaytire wetland, an Andean high-altitude wetland in Peru Comunidade de microalgas do wetland Huaytire, uma área alagada de alta altitude nos Andes peruanos

    Directory of Open Access Journals (Sweden)

    Gian Salazar-Torres

    2012-01-01

    Full Text Available AIM: The diversity and distribution of microalgae communities in a high-altitude (3,000 to 4,500 m a.s.l Andean wetland, regionally known as bofedal, were examined to assess seasonal and spatial patterns. METHODS: Samples were taken monthly from June to December, 2008 at 13 stations in the Huaytire wetland (16° 54’ S and 70° 20’ W, covering three areas (impacted by urban land use, impacted by camelid pasture, and non-impacted and three climatologically induced periods (ice-covered, ice-melt and ice-free. RESULTS: A total of 52 genera of algae were recorded. Diatoms were the predominant group in abundance and richness. We found a significantly higher abundance during the ice-melting period, when light exposure and runoff were intermediate, in comparison to the ice-covered (low light and flushing and ice-free (high light and low runoff periods. Microalgae abundance was significantly lower in the non-impacted area compared to the sites close to the urban area and to the camelid pastures. Alpha diversity ranged from 8 to 29 genera per sample. High genera exchange was observed throughout the wetland, showing a similar floristic composition (beta diversity = 4%. CONCLUSIONS: We found that diatoms were dominant and adapted to the extreme conditions of the Andean wetland, showing higher abundance during the ice-melt period and in the livestock area. Also, taxa richness was higher in the ice-melt period and in the most-impacted areas.OBJETIVO: A diversidade e distribuição da comunidade de microalgas em uma área alagada nos Andes (3.000 a 4.500 m de altitude, regionalmente conhecido como bofedal, foram examinadas para avaliar seus padrões sazonais e espaciais. MÉTODOS: As amostras foram coletadas, mensalmente, de junho a dezembro de 2008, em 13 estações no bofedal Huaytire (16° 54’ S e 70° 20’ W, abrangendo três áreas (impactada por ação urbana, impactada por pastagem de gado camelídeo e área não impactada e três per

  10. Physiological aspects of altitude training and the use of altitude simulators

    OpenAIRE

    Ranković Goran; Radovanović Dragan

    2005-01-01

    Altitude training in various forms is widely practiced by athletes and coaches in an attempt to improve sea level endurance. Training at high altitude may improve performance at sea level through altitude acclimatization, which improves oxygen transport and/or utilization, or through hypoxia, which intensifies the training stimulus. This basic physiological aspect allows three training modalities: live high and train high (classic high-altitude training), live low and train high (training thr...

  11. Scientific Approach for Optimising Performance, Health and Safety in High-Altitude Observatories

    Science.gov (United States)

    Böcker, Michael; Vogy, Joachim; Nolle-Gösser, Tanja

    2008-09-01

    The ESO coordinated study “Optimising Performance, Health and Safety in High-Altitude Observatories” is based on a psychological approach using a questionnaire for data collection and assessment of high-altitude effects. During 2007 and 2008, data from 28 staff and visitors involved in APEX and ALMA were collected and analysed and the first results of the study are summarised. While there is a lot of information about biomedical changes at high altitude, relatively few studies have focussed on psychological changes, for example with respect to performance of mental tasks, safety consciousness and emotions. Both, biomedical and psychological changes are relevant factors in occupational safety and health. The results of the questionnaire on safety, health and performance issues demonstrate that the working conditions at high altitude are less detrimental than expected.

  12. Unchanged cerebral blood flow and oxidative metabolism after acclimatization to high altitude

    DEFF Research Database (Denmark)

    Møller, Kirsten; Paulson, Olaf B; Hornbein, Thomas F.

    2002-01-01

    The authors investigated the effect of acclimatization to high altitude on cerebral blood flow and oxidative metabolism at rest and during exercise. Nine healthy, native sea-level residents were studied 3 weeks after arrival at Chacaltaya, Bolivia (5,260 m) and after reacclimatization to sea level....... At high altitude at rest, arterial carbon dioxide tension, oxygen saturation, and oxygen tension were significantly reduced, and arterial oxygen content was increased because of an increase in hemoglobin concentration. Global cerebral blood flow was similar in the four conditions. Cerebral oxygen delivery...... and cerebral metabolic rates of oxygen and glucose also remained unchanged, whereas cerebral metabolic rates of lactate increased slightly but nonsignificantly at high altitude during exercise compared with high altitude at rest. Reaction time was unchanged. The data indicate that cerebral blood flow...

  13. Design study for remotely piloted, high-altitude airplanes powered by microwave energy

    Science.gov (United States)

    Morris, C. E. K., Jr.

    1983-01-01

    A design study has been conducted for unmanned, microwave-powered airplanes that must fly with long endurance at high altitude. They are proposed to conduct communications-relay, observation, or various scientific missions above approximately 55,000 feet altitude. The special characteristics of the microwave-power system and high-altitude, low-speed vehicle are reviewed. Examples of both sizing and performance analysis are used to suggest design procedure guidelines.

  14. High altitude pulmonary edema among "Amarnath Yatris"

    Directory of Open Access Journals (Sweden)

    Parvaiz A Koul

    2013-01-01

    Full Text Available Background: Annual pilgrimage (Yatra to the cave shrine of Shri Amarnath Ji′ is a holy ritual among the Hindu devotees of Lord Shiva. Located in the Himalayan Mountain Range (altitude 13,000 ft in south Kashmir, the shrine is visited by thousands of devotees and altitude sickness is reportedly common. Materials and Methods: More than 600,000 pilgrims visited the cave shrine in 2011 and 2012 with 239 recorded deaths. Thirty one patients with suspected altitude sickness were referred from medical centers en-route the cave to Sher-i-Kashmir Institute of Medical Sciences, a tertiary-care center in capital Srinagar (5,000 ft. The clinical features and the response to treatment were recorded. Results: Thirty-one patients (all lowlanders, 19 male; age 18-60 years, median 41 had presented with acute onset breathlessness of 1-4 days (median 1.9 d starting within 12-24 h of a rapid ascent; accompanied by cough (68%, headache (8%, dizziness and nausea (65%. Sixteen patients had associated encephalopathy. Clinical features on admission included tachypnea ( n = 31, tachycardia ( n = 23, bilateral chest rales ( n = 29, cyanosis ( n = 22 and grade 2-4 encephalopathy. Hypoxemia was demonstrable in 24 cases and bilateral infiltrates on radiologic imaging in 29. Ten patients had evidence of high-altitude cerebral edema. All patients were managed with oxygen, steroids, nifedipine, sildenafil and other supportive measures including invasive ventilation ( n = 3. Three patients died due to multiorgan dysfunction. Conclusions: Altitude sickness is common among Amaranath Yatris from the plains and appropriate educational strategies should be invoked for prevention and prompt treatment.

  15. Novel drugs in the management of acute mountain sickness and high altitude pulmonary edema

    Directory of Open Access Journals (Sweden)

    Sikri G

    2015-12-01

    Full Text Available Gaurav Sikri, Anirban Bhattacharya Department of Physiology, Armed Forces Medical College, Wanowarie, Pune, IndiaWe read with great interest the review article titled “Wilderness medicine at high altitude: recent developments in the field” by Shah et al.1 The authors have comprehensively summarized the recent advances in the field of high altitude medicine relevant to sports and travel medicine. However, Shah et al have described potential drugs for management of high-altitude illnesses, such as acute mountain sickness (AMS, high altitude cerebral edema, and high altitude pulmonary edema (HAPE as one group under the section “Novel drug treatment for AMS”. The pathophysiologies of these two sets of diseases (AMS/high altitude cerebral edema as one and HAPE as another set are different2 and hence it would have been nice to have had the novel drugs described separately to elucidate the therapeutic approach for the two different classes of diseases.View original paper by Shah et al.

  16. Polar Ice Caps: a Canary for the Greenland Ice Sheet

    Science.gov (United States)

    Honsaker, W.; Lowell, T. V.; Sagredo, E.; Kelly, M. A.; Hall, B. L.

    2010-12-01

    Ice caps are glacier masses that are highly sensitive to climate change. Because of their hypsometry they can have a binary state. When relatively slight changes in the equilibrium line altitude (ELA) either intersect or rise above the land the ice can become established or disappear. Thus these upland ice masses have a fast response time. Here we consider a way to extract the ELA signal from independent ice caps adjacent to the Greenland Ice Sheet margin. It may be that these ice caps are sensitive trackers of climate change that also impact the ice sheet margin. One example is the Istorvet Ice Cap located in Liverpool Land, East Greenland (70.881°N, 22.156°W). The ice cap topography and the underlying bedrock surface dips to the north, with peak elevation of the current ice ranging in elevation from 1050 to 745 m.a.s.l. On the eastern side of the ice mass the outlet glaciers extending down to sea level. The western margin has several small lobes in topographic depressions, with the margin reaching down to 300 m.a.s.l. Topographic highs separate the ice cap into at least 5 main catchments, each having a pair of outlet lobes toward either side of the ice cap. Because of the regional bedrock slope each catchment has its own elevation range. Therefore, as the ELA changes it is possible for some catchments of the ice cap to experience positive mass balance while others have a negative balance. Based on weather observations we estimate the present day ELA to be ~1000 m.a.s.l, meaning mass balance is negative for the majority of the ice cap. By tracking glacier presence/absence in these different catchments, we can reconstruct small changes in the ELA. Another example is the High Ice Cap (informal name) in Milne Land (70.903°N, 25.626°W, 1080 m), East Greenland. Here at least 4 unconformities in ice layers found near the southern margin of the ice cap record changing intervals of accumulation and ablation. Therefore, this location may also be sensitive to slight

  17. Kajian Teknologi High Altitude Platform (HAP [Study of High Altitude Platform (HAP Technology

    Directory of Open Access Journals (Sweden)

    Amry Daulat Gultom

    2016-07-01

    Full Text Available High Altitude Platform (HAP merupakan solusi alternatif untuk mengatasi keterbatasan infrastruktur terestrial maupun satelit. HAP merupakan pesawat ataupun balon udara yang ditempatkan pada ketinggian 20-50 km di atas permukaan bumi. Kelebihan yang utama dari HAP adalah kemudahan dalam penempatan, fleksibilitas, biaya operasionalnya rendah, delay  propagasi rendah, sudut elevasi lebar, cakupan yang luas. Penelitian ini dilakukan untuk mengetahui potensi HAP untuk komunikasi pita lebar dan perkembangannya di Indonesia. Analisis dilakukan secara deskriptif dengan mengolah data literatur yang didapat. Hasil penelitian menunjukkan bahwa di Indonesia terdapat potensi teknologi HAP untuk komunikasi pita lebar dengan lebar pita 2x300 MHz di band 27,9-28,2 GHz dan 31-31,3 GHz. Namun, belum ada peraturan yang mengatur alokasi frekuensi untuk HAP secara khusus di Indonesia.*****High Altitude Platform (HAP has been developed as an alternative solution in order to overcome limitation of terrestrial and satellite communication system. HAP is an aircraft or balloon situated on 20-50 km above the earth. Main advantages of HAP are flexibility in deployment, low propagation delay, wide elevation angle and broad coverage. The research is conducted to gather HAP potential for broadband communication and its development in Indonesia. Analysis is conducted by descriptive analysis from literature study gather. The research result shows that in Indonesia, there is potential of HAP technology for broadband communication with 2x300 MHz bandwidth within 27,9-28,2 GHz and 31-31,3 GHz. Yet, there are no specific regulations managing frequency allocation for HAP in Indonesia.

  18. Difference in blood microcirculation recovery between normal frostbite and high-altitude frostbite

    Directory of Open Access Journals (Sweden)

    Ming-ke JIAO

    2017-02-01

    Full Text Available Objective To determine the difference in blood microcirculation recovery between normal frostbite and high-altitude frostbite during the wound healing. Methods Twenty four male rats were randomly divided into control group (n=8, normal frostbite group (n=8, and high-altitude group (n=8. The normal frostbite group rats were frozen to produce mid-degree frostbite models by controlling the freezing time with liquid nitrogen penetration equipment. The high-altitude frostbite group rats were acclimated to a hypoxic and low-pressure environment for 1 week, and then the high-altitude frostbite models were constructed by the same way with liquid nitrogen penetration apparatus. On days 3, 7, 11, 15, 19, and 23 after modeling, the recovery situation of blood circulation of each group was observed with contrast ultrasonography by injecting SonoVue micro-bubble into rats' tail. Finally, the micro-bubble concentration (MC was calculated to confirm the blood circulation recovery with software Image Pro. Results At different time points, the wound area of the high-altitude frostbite group was bigger than that of the normal frostbite group, and the MC of control group was always about (27±0.2×109/ml. On day 3, 7, 11, 15, 19, and 23, the MC was significantly lower in the high-altitude frostbite group than in the control group and normal frostbite group (P<0.05. The MC of normal frostbite group was significantly lower than that of the control group on day 3, 7, 11, 15 and 19 (P<0.05. In addition, no obvious difference in MC was found between normal group and control group on the 23th day (P<0.05. Conclusion The blood microcirculation recovery after high-altitude frostbite is significantly slower than the normal frostbite. DOI: 10.11855/j.issn.0577-7402.2017.01.13

  19. Civilian Training in High-Altitude Flight Physiology

    Science.gov (United States)

    1991-08-01

    A survey was conducted to determine if training in high-altitude physiology should : be required for civilian pilots; what the current status of such training was; and, : if required, what should be included in an ideal curriculum. The survey include...

  20. Investigating cosmic rays and air shower physics with IceCube/IceTop

    Science.gov (United States)

    Dembinski, Hans

    2017-06-01

    IceCube is a cubic-kilometer detector in the deep ice at South Pole. Its square-kilometer surface array, IceTop, is located at 2800 m altitude. IceTop is large and dense enough to cover the cosmic-ray energy spectrum from PeV to EeV energies with a remarkably small systematic uncertainty, thanks to being close to the shower maximum. The experiment offers new insights into hadronic physics of air showers by observing three components: the electromagnetic signal at the surface, GeV muons in the periphery of the showers, and TeV muons in the deep ice. The cosmic-ray flux is measured with the surface signal. The mass composition is extracted from the energy loss of TeV muons observed in the deep ice in coincidence with signals at the surface. The muon lateral distribution is obtained from GeV muons identified in surface signals in the periphery of the shower. The energy spectrum of the most energetic TeV muons is also under study, as well as special events with laterally separated TeV muon tracks which originate from high-pT TeV muons. A combination of all these measurements opens the possibility to perform powerful new tests of hadronic interaction models used to simulate air showers. The latest results will be reviewed from this perspective.

  1. Investigating cosmic rays and air shower physics with IceCube/IceTop

    Directory of Open Access Journals (Sweden)

    Dembinski Hans

    2017-01-01

    Full Text Available IceCube is a cubic-kilometer detector in the deep ice at South Pole. Its square-kilometer surface array, IceTop, is located at 2800 m altitude. IceTop is large and dense enough to cover the cosmic-ray energy spectrum from PeV to EeV energies with a remarkably small systematic uncertainty, thanks to being close to the shower maximum. The experiment offers new insights into hadronic physics of air showers by observing three components: the electromagnetic signal at the surface, GeV muons in the periphery of the showers, and TeV muons in the deep ice. The cosmic-ray flux is measured with the surface signal. The mass composition is extracted from the energy loss of TeV muons observed in the deep ice in coincidence with signals at the surface. The muon lateral distribution is obtained from GeV muons identified in surface signals in the periphery of the shower. The energy spectrum of the most energetic TeV muons is also under study, as well as special events with laterally separated TeV muon tracks which originate from high-pT TeV muons. A combination of all these measurements opens the possibility to perform powerful new tests of hadronic interaction models used to simulate air showers. The latest results will be reviewed from this perspective.

  2. Aspirated Compressors for High Altitude Engines, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Aurora Flight Sciences proposes to incorporate aspirated compressor technology into a high altitude, long endurance (HALE) concept engine. Aspiration has been proven...

  3. Study on Oxygen Supply Standard for Physical Health of Construction Personnel of High-Altitude Tunnels

    Directory of Open Access Journals (Sweden)

    Chun Guo

    2015-12-01

    Full Text Available The low atmospheric pressure and low oxygen content in high-altitude environment have great impacts on the functions of human body. Especially for the personnel engaged in complicated physical labor such as tunnel construction, high altitude can cause a series of adverse physiological reactions, which may result in multiple high-altitude diseases and even death in severe cases. Artificial oxygen supply is required to ensure health and safety of construction personnel in hypoxic environments. However, there are no provisions for oxygen supply standard for tunnel construction personnel in high-altitude areas in current tunnel construction specifications. As a result, this paper has theoretically studied the impacts of high-altitude environment on human bodies, analyzed the relationship between labor intensity and oxygen consumption in high-altitude areas and determined the critical oxygen-supply altitude values for tunnel construction based on two different standard evaluation systems, i.e., variation of air density and equivalent PIO2. In addition, it has finally determined the oxygen supply standard for construction personnel in high-altitude areas based on the relationship between construction labor intensity and oxygen consumption.

  4. Investigating the Microscopic Location of Trace Elements in High-Alpine Glacier Ice

    Science.gov (United States)

    Avak, Sven Erik; Birrer, Mario; Laurent, Oscar; Guillong, Marcel; Wälle, Markus; Jenk, Theo Manuel; Bartels-Rausch, Thorsten; Schwikowski, Margit; Eichler, Anja

    2017-04-01

    proxies in glaciers partially affected by melting. References Della Lunga, D., Müller, W., Rasmussen, S. O. & Svensson, A. 2014: Location of cation impurities in NGRIP deep ice revealed by cryo-cell UV-laser-ablation ICPMS, Journal of Glaciology, 60, 970-988. Eichler, A., Schwikowski, M., Gäggeler, H. W. 2001: Meltwater-induced relocation of chemical species in Alpine firn, Tellus B, 53, 192-203. Reinhardt, H., Kriews, M., Miller, H., Schrems, O., Lüdke, C., Hoffmann, E. & Skole, J. 2001: Laser ablation inductively coupled plasma mass spectrometry: a new tool for trace element analysis in ice cores, Fresenius' Journal of Analytical Chemistry, 370, 629-636. Schwikowski, M., Barbante, C., Doering, T., Gäggeler, H. W., Boutron, C., Schotterer, U., Tobler, L., van de Velde, K., Ferrari, C., Cozzi, G., Rosman, K., Cescon, P. 2004: Post-17th-Century Changes of European Lead Emissions Recorded in High-Altitude Alpine Snow and Ice, Environmental Science & Technology, 38, 957-964. Sneed, S. B., Mayewski, P. A., Sayre, W. G., Handley, M. J., Kurbatov, A. V., Taylor, K. C., Bohleber, P., Wagenbach, D., Erhardt, T. & Spaulding, N. E. 2015: New LA-ICP-MS cryocell and calibration technique for sub-millimeter analysis of ice cores, Journal of Glaciology, 61, 233-242.

  5. Climate Change Impacts on High-Altitude Ecosystems

    OpenAIRE

    Harald Pauli

    2016-01-01

    Reviewed: Climate Change Impacts on High-Altitude Ecosystems By Münir Öztürk, Khalid Rehman Hakeem, I. Faridah-Hanum and Efe. Recep, Cham, Switzerland: Springer International Publishing, 2015. xvii + 696 pp. US$ 239.00. ISBN 978-3-319-12858-0.

  6. Effect of egg composition and oxidoreductase on adaptation of Tibetan chicken to high altitude.

    Science.gov (United States)

    Jia, C L; He, L J; Li, P C; Liu, H Y; Wei, Z H

    2016-07-01

    Tibetan chickens have good adaptation to hypoxic conditions, which can be reflected by higher hatchability than lowland breeds when incubated at high altitude. The objective of this trial was to study changes in egg composition and metabolism with regards the adaptation of Tibetan chickens to high altitude. We measured the dry weight of chicken embryos, egg yolk, and egg albumen, and the activity of lactate dehydrogenase (LDH) and succinic dehydrogenase (SDH) in breast muscle, heart, and liver from embryos of Tibetan chicken and Dwarf chicken (lowland breed) incubated at high (2,900 m) and low (100 m) altitude. We found that growth of chicken embryos was restricted at high altitude, especially for Dwarf chicken embryos. In Tibetan chicken, the egg weight was lighter, but the dry weight of egg yolk was heavier than that of Dwarf chicken. The LDH activities of the three tissues from the high altitude groups were respectively higher than those of the lowland groups from d 15 to hatching, except for breast muscle of Tibetan chicken embryos on d 15. In addition, under the high altitude environment, the heart tissue from Tibetan chicken had lower LDH activity than that from Dwarf chicken at d 15 and 18. The lactic acid content of blood from Tibetan chicken embryos was lower than that of Dwarf chicken at d 12 and 15 of incubation at high altitude. There was no difference in SDH activity in the three tissues between the high altitude groups and the lowland groups except in three tissues of hatchlings and at d 15 of incubation in breast muscle, nor between the two breeds at high altitude except in the heart of hatchlings. Consequently, the adaptation of Tibetan chicken to high altitude may be associated with higher quantities of yolk in the egg and a low metabolic oxygen demand in tissue, which illuminate the reasons that the Tibetan chicken have higher hatchability with lower oxygen transport ability. © 2016 Poultry Science Association Inc.

  7. Incidence and Symptoms of High Altitude Illness in South Pole Workers: Antarctic Study of Altitude Physiology (ASAP

    Directory of Open Access Journals (Sweden)

    Paul J. Anderson

    2011-01-01

    Full Text Available Introduction Each year, the US Antarctic Program rapidly transports scientists and support personnel from sea level (SL to the South Pole (SP, 2835 m providing a unique natural laboratory to quantify the incidence of acute mountain sickness (AMS, patterns of altitude related symptoms and the field effectiveness of acetazolamide in a highly controlled setting. We hypothesized that the combination of rapid ascent (3 hr, accentuated hypobarism (relative to altitude, cold, and immediate exertion would increase altitude illness risk. Methods Medically screened adults (N = 246, age = 37 ± 11 yr, 30% female, BMI = 26 ± 4 kg/m 2 were recruited. All underwent SL and SP physiological evaluation, completed Lake Louise symptom questionnaires (LLSQ, to define AMS, and answered additional symptom related questions (eg, exertional dyspnea, mental status, cough, edema and general health, during the 1st week at altitude. Acetazolamide, while not mandatory, was used by 40% of participants. Results At SP, the barometric pressure resulted in physiological altitudes that approached 3400 m, while T ° C averaged -42, humidity 0.03%. Arterial oxygen saturation averaged 89% ± 3%. Overall, 52% developed LLSQ defined AMS. The most common symptoms reported were exertional dyspnea-(87%, sleeping difficulty-(74%, headache-(66%, fatigue-(65%, and dizziness/lightheadedness-(46%. Symptom severity peaked on days 1-2, yet in >20% exertional dyspnea, fatigue and sleep problems persisted through day 7. AMS incidence was similar between those using acetazolamide and those abstaining (51 vs. 52%, P = 0.87. Those who used acetazolamide tended to be older, have less altitude experience, worse symptoms on previous exposures, and less SP experience. Conclusion The incidence of AMS at SP tended to be higher than previously reports in other geographic locations at similar altitudes. Thus, the SP constitutes a more intense altitude exposure than might be expected considering physical

  8. Butterflies of the high altitude Atacama Desert: habitat use and conservation

    Directory of Open Access Journals (Sweden)

    Emma eDespland

    2014-09-01

    Full Text Available The butterfly fauna of the high-altitude desert of Northern Chile, though depauperate, shows high endemism, is poorly known and is of considerable conservation concern. This study surveys butterflies along the Andean slope between 2400 and 500 m asl (prepuna, puna and Andean steppe habitats as well as in high and low altitude wetlands and in the neoriparian vegetation of agricultural sites. We also include historical sightings from museum records. We compare abundances between altitudes, between natural and impacted sites, as well as between two sampling years with different precipitation regimes. The results confirm high altitudinal turnover and show greatest similarity between wetland and slope faunas at similar altitudes. Results also underscore vulnerability to weather fluctuations, particularly in the more arid low-altitude sites, where abundances were much lower in the low precipitation sampling season and several species were not observed at all. Finally, we show that some species have shifted to the neoriparian vegetation of the agricultural landscape, whereas others were only observed in less impacted habitats dominated by native plants. These results suggest that acclimation to novel habitats depends on larval host plant use. The traditional agricultural environment can provide habitat for many, but not all, native butterfly species, but an estimation of the value of these habitats requires better understanding of butterfly life-history strategies and relationships with host plants.

  9. High altitude-induced albuminuria in normal man is enhanced by infusion of low-dose dopamine

    DEFF Research Database (Denmark)

    Hansen, J M; Kanstrup, I L; Richalet, J P

    1996-01-01

    -85) (median with quartiles in parentheses) at high altitude. High altitude hypoxia increased Ualb from 3.2 micrograms min-1 (2.7-3.5) to 5.0 micrograms min-1 (3.3-6.6) (p ... flow (ERPF) from 465 ml min-1 (412-503) to 410 ml min-1 (385-451) (p high altitude. Dopamine...... increased ERPF, GFR, CLi, CNa, and decreased the filtration fraction in both environments. Infusion of dopamine further increased Ualb to 10.5 micrograms min-1 (5.5-64.8) (p high altitude, but had no effect on Ualb at sea level. In conclusion, high altitude hypoxia per se increases the urinary...

  10. Climate Change Impacts on High-Altitude Ecosystems

    Directory of Open Access Journals (Sweden)

    Harald Pauli

    2016-02-01

    Full Text Available Reviewed: Climate Change Impacts on High-Altitude Ecosystems By Münir Öztürk, Khalid Rehman Hakeem, I. Faridah-Hanum and Efe. Recep, Cham, Switzerland: Springer International Publishing, 2015. xvii + 696 pp. US$ 239.00. ISBN 978-3-319-12858-0.

  11. SPLENIC INFARCTION: an intriguing and important cause of pain abdomen in high altitude

    Directory of Open Access Journals (Sweden)

    P. K. Hota

    2015-01-01

    Full Text Available Background: Patients with Sickle cell trait (SCT are usually asymptomatic. They are usually unaware of their condition unless they have a family history. There are specific situations, where these people suffer from the effects of sickle cell trait. Splenic syndrome at high altitude is one of the specific problems. It is usually seen after a patient with SCT has been inducted to high altitude like in case of mountaineers and military personnel deployed in high altitude warfare. Pain abdomen due to splenic infarction in individuals with SCT is one of the manifestations. These patients, if diagnosed in time, they can be spared from unnecessary surgical interventions. We present herewith our experience of splenic infarction due to SCT in high altitude and their management.

  12. Experimental StudyHigh Altitude Forced Convective Cooling of Electromechanical Actuation Systems

    Science.gov (United States)

    2016-01-01

    34 Massachusetts Institute of Technology , 1989. [3] FedBizOps.Gov, " Integrated Vehicle Energy Technology (INVENT) Development Program for the 6th...AFRL-RQ-WP-TR-2016-0043 EXPERIMENTAL STUDY—HIGH ALTITUDE FORCED CONVECTIVE COOLING OF ELECTROMECHANICAL ACTUATION SYSTEMS Evan M. Racine...TITLE AND SUBTITLE EXPERIMENTAL STUDY—HIGH ALTITUDE FORCED CONVECTIVE COOLING OF ELECTROMECHANICAL ACTUATION SYSTEMS 5a. CONTRACT NUMBER In-house

  13. Text mining and network analysis to find functional associations of genes in high altitude diseases.

    Science.gov (United States)

    Bhasuran, Balu; Subramanian, Devika; Natarajan, Jeyakumar

    2018-05-02

    Travel to elevations above 2500 m is associated with the risk of developing one or more forms of acute altitude illness such as acute mountain sickness (AMS), high altitude cerebral edema (HACE) or high altitude pulmonary edema (HAPE). Our work aims to identify the functional association of genes involved in high altitude diseases. In this work we identified the gene networks responsible for high altitude diseases by using the principle of gene co-occurrence statistics from literature and network analysis. First, we mined the literature data from PubMed on high-altitude diseases, and extracted the co-occurring gene pairs. Next, based on their co-occurrence frequency, gene pairs were ranked. Finally, a gene association network was created using statistical measures to explore potential relationships. Network analysis results revealed that EPO, ACE, IL6 and TNF are the top five genes that were found to co-occur with 20 or more genes, while the association between EPAS1 and EGLN1 genes is strongly substantiated. The network constructed from this study proposes a large number of genes that work in-toto in high altitude conditions. Overall, the result provides a good reference for further study of the genetic relationships in high altitude diseases. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. Cognitive Changes during Prolonged Stay at High Altitude and Its Correlation with C-Reactive Protein.

    Directory of Open Access Journals (Sweden)

    Sheng Li Hu

    Full Text Available Hypersensitive C-reaction protein (hsCRP may be a risk factor for cognitive impairment resulting from Alzheimer's disease (AD, stroke, and vascular dementia. This study explored the correlation of peripheral blood hsCRP level with cognitive decline due to high altitude exposure. The study was conducted on 100 male military participants who had never been to high altitude. Cerebral oxygen saturation monitoring, event related potentials (P300, N200 detection, and neurocognitive assessment was performed and total hsCRP, interleukin-6 (IL-6, and homocysteine was estimated at 500 m altitude, 3650 m altitude, 3 day, 1, and 3 month post arriving at the base camp (4400 m, and 1 month after coming back to the 500 m altitude. High altitude increased brain oxygen saturation, prolonged P300 and N200 latencies, injured cognitive functions, and raised plasma hsCRP levels. But they all recovered in varying degrees at 1 and 3 month post arriving at the base camp (4400 m. P300 latencies and hsCRP levels were strongly correlated to cognitive performances. These results suggested that cognitive deterioration occurred during the acute period of exposure to high altitude and may recover probably owning to acclimatization after extended stay at high altitude. Plasma hsCRP is inversely correlated to neurological cognition and it may be a potential biomarker for the prediction of high altitude induced cognitive dysfunction.

  15. Functions and Design Scheme of Tibet High Altitude Test Base

    Institute of Scientific and Technical Information of China (English)

    Yu Yongqing; Guo Jian; Yin Yu; Mao Yan; Li Guangfan; Fan Jianbin; Lu Jiayu; Su Zhiyi; Li Peng; Li Qingfeng; Liao Weiming; Zhou Jun

    2010-01-01

    @@ The functional orientation of the Tibet High Altitude Test Base, subordinated to the State Grid Corporation of China (SGCC), is to serve power transmission projects in high altitude areas, especially to provide technical support for southwestern hydropower delivery projects by UHVDC transmission and Qinghai-Tibet grid interconnection project. This paper presents the matters concerned during siting and planning, functions,design scheme, the main performances and parameters of the test facilities, as well as the tests and research tasks already carried out.

  16. Effect of phosphate supplementation on oxygen delivery at high altitude

    Science.gov (United States)

    Jain, S. C.; Singh, M. V.; Rawal, S. B.; Sharma, V. M.; Divekar, H. M.; Tyagi, A. K.; Panwar, M. R.; Swamy, Y. V.

    1987-09-01

    In the present communication, effect of low doses of phosphate supplementation on short-term high altitude adaptation has been examined. Studies were carried out in 36 healthy, male, sea-level residents divided in a double blind fashion into drug and placebo treated groups. 3.2 mmol of phosphate were given orally to each subject of the drug treated group once a day for 4 days on arrival at an altitude of 3,500 m. Sequential studies were done in the subjects in both groups on the 3rd, 7th, 14th and 21st day of their altitude stay. Haemoglobin, haematocrit, erythrocyte and reticulocyte counts increased to the similar extent in both groups. Blood pH, pO2 and adenosine tri-phosphate (ATP) did not differ between the two groups. On 3rd day of the altitude stay, inorganic phosphate and 2,3-diphosphoglycerate (2,3 DPG) levels in the drug treated group increased significantly as compared to the placebo group. No significant difference in inorganic phosphate and 2,3 DPG was observed later on in the two groups. Psychological and clinical tests also indicated that the drug treated subjects felt better as compared to the placebo treated subjects. The present study suggests that low doses of phosphate increases circulating 2,3-DPG concentration which in turn brings about beneficial effect towards short term high altitude adaptation.

  17. Differentiation of pulmonary embolism from high altitude pulmonary edema

    International Nuclear Information System (INIS)

    Khan, D.A.; Hashim, R.; Mirza, T.M.; Matloob-ur-Rehman, M.

    2003-01-01

    Objective: To differentiate the high altitude pulmonary edema (HAPE) from pulmonary embolism (PE) by clinical probability model of PE, lactate dehydrogenase (LDH), aspartate transaminase (AST) and D-dimer assays at high altitude. Subjects and Methods: Consecutive 40 patients evacuated from height > 3000 meters with symptoms of PE or HAPE were included. Clinical pretest probabilities scores of PE, Minutex D-dimer assay (Biopool international) and cardiac enzymes estimation by IFCC approved methods, were used for diagnosis. Mann-Whitney U test was applied by using SPSS and level of significance was taken at (p 500 ng/ml. Plasma D-dimer of 500 ng/ml was considered as cut-off value; 6(66.7%) patients of PE could be diagnosed and 30 (96.7%) cases of HAPE excluded indicating very good negative predictive value. Serum LDH, AST and CK were raised above the reference ranges in 8 (89%), 7 (78%) and 3 (33%) patients of PE as compared to 11 (35%), 6 (19%) and 9 (29%) of HAPE respectively. Conclusion: Clinical assessment in combination with D-dimer assay, LDH and AST can be used for timely differentiation of PE from HAPE at high altitude where diagnostic imaging procedures are not available. (author)

  18. Measurements of radioactive dust in high altitude air

    International Nuclear Information System (INIS)

    Kobayashi, Mika; Kohara, Eri; Muronoi, Naohiro; Masuda, Yousuke; Midou, Tomotaka; Ishida, Yukiko; Shimizu, Toshihiko; Saga, Minoru; Endo, Hiromu

    2012-01-01

    The radioactivity in samples of airborne dust was measured. The samples had been collected at high altitude by the Japan Air Self-Defense Force. The data were obtained for the gross beta activity, gamma nuclide determination and radiochemical analysis. It was shown that there was no appreciable difference between the activity levels obtained in this time and in the year before. Seasonal variations were not very pronounced. It was found that the radioactivity at high altitude had been stable at a low level. Radioactive gases (gaseous radioiodine and xenon gas) were not detected. This report does not include the result on radionuclide measurements that Technical Research and Development Institute executed for examining the nuclear emergency situation at Fukushima Daiichi and Daini nuclear power plants after Tohoku Region Pacific Ocean Earthquake on March 11, 2011. (author)

  19. Rare Particle Searches with the high altitude SLIM experiment

    CERN Document Server

    Balestra, S; Fabbri, F; Giacomelli, G; Giacomelli, R; Giorgini, M; Kumar, A; Manzoor, S; McDonald, J; Margiotta, A; Medinaceli, E; Nogales, J; Patrizii, L; Popa, V; Quereshi, I; Saavedra, O; Sher, G; Shahzad, M; Spurio, M; Ticona, R; Togo, V; Velarde, A; Zanini, A

    2005-01-01

    The search for rare particles in the cosmic radiation remains one of the main aims of non-accelerator particle astrophysics. Experiments at high altitude allow lower mass thresholds with respect to detectors at sea level or underground. The SLIM experiment is a large array of nuclear track detectors located at the Chacaltaya High Altitude Laboratory (5290 m a.s.l.). The preliminary results from the analysis of a part of the first 236 sq.m exposed for more than 3.6 y are here reported. The detector is sensitive to Intermediate Mass Magnetic Monopoles and to SQM nuggets and Q-balls, which are possible Dark Matter candidates.

  20. High Altitude Balloons as a Platform for Space Radiation Belt Science

    Science.gov (United States)

    Mazzino, L.; Buttenschoen, A.; Farr, Q.; Hodgson, C.; Johnson, W.; Mann, I. R.; Rae, J.; University of Alberta High Altitude Balloons (UA-HAB)

    2011-12-01

    The goals of the University of Alberta High Altitude Balloons Program (UA-HAB) are to i) use low cost balloons to address space radiation science, and ii) to utilise the excitement of "space mission" involvement to promote and facilitate the recruitment of undergraduate and graduate students in physics, engineering, and atmospheric sciences to pursue careers in space science and engineering. The University of Alberta High Altitude Balloons (UA-HAB) is a unique opportunity for University of Alberta students (undergraduate and graduate) to engage in the hands-on design, development, build, test and flight of a payload to operate on a high altitude balloon at around 30km altitude. The program development, including formal design and acceptance tests, reports and reviews, mirror those required in the development of an orbital satellite mission. This enables the students to gain a unique insight into how space missions are flown. UA-HAB is a one and half year program that offers a gateway into a high-altitude balloon mission through hands on experience, and builds skills for students who may be attracted to participate in future space missions in their careers. This early education will provide students with the experience necessary to better assess opportunities for pursuing a career in space science. Balloons offer a low-cost alternative to other suborbital platforms which can be used to address radiation belt science goals. In particular, the participants of this program have written grant proposal to secure funds for this project, have launched several 'weather balloon missions', and have designed, built, tested, and launched their particle detector called "Maple Leaf Particle Detector". This detector was focussed on monitoring cosmic rays and space radiation using shielded Geiger tubes, and was flown as one of the payloads from the institutions participating in the High Altitude Student Platform (HASP), organized by the Louisiana State University and the Louisiana

  1. Sequencing of 50 human exomes reveals adaptation to high altitude

    DEFF Research Database (Denmark)

    Yi, Xin; Liang, Yu; Huerta-Sanchez, Emilia

    2010-01-01

    Residents of the Tibetan Plateau show heritable adaptations to extreme altitude. We sequenced 50 exomes of ethnic Tibetans, encompassing coding sequences of 92% of human genes, with an average coverage of 18x per individual. Genes showing population-specific allele frequency changes, which repres...... in genetic adaptation to high altitude.......Residents of the Tibetan Plateau show heritable adaptations to extreme altitude. We sequenced 50 exomes of ethnic Tibetans, encompassing coding sequences of 92% of human genes, with an average coverage of 18x per individual. Genes showing population-specific allele frequency changes, which...... represent strong candidates for altitude adaptation, were identified. The strongest signal of natural selection came from endothelial Per-Arnt-Sim (PAS) domain protein 1 (EPAS1), a transcription factor involved in response to hypoxia. One single-nucleotide polymorphism (SNP) at EPAS1 shows a 78% frequency...

  2. Relative Match Intensities at High Altitude in Highly-Trained Young Soccer Players (ISA3600).

    Science.gov (United States)

    Buchheit, Martin; Hammond, Kristal; Bourdon, Pitre C; Simpson, Ben M; Garvican-Lewis, Laura A; Schmidt, Walter F; Gore, Christopher J; Aughey, Robert J

    2015-03-01

    To compare relative match intensities of sea-level versus high-altitude native soccer players during a 2-week camp at 3600 m, data from 7 sea-level (Australian U17 National team, AUS) and 6 high-altitude (a Bolivian U18 team, BOL) native soccer players were analysed. Two matches were played at sea-level and three at 3600 m on Days 1, 6 and 13. The Yo-Yo Intermittent recovery test (vYo-YoIR1) was performed at sea-level, and on Days 3 and 10. Match activity profiles were measured via 10-Hz GPS. Distance covered >14.4 km.h(-1) (D>14.4 km·h(-1)) and >80% of vYo-YoIR1 (D>80%vYo-YoIR1) were examined. Upon arrival at altitude, there was a greater decrement in vYo-YoIR1 (Cohen's d +1.0, 90%CL ± 0.8) and D>14.4 km·h(-1) (+0.5 ± 0.8) in AUS. D>14.4 km.h(-1) was similarly reduced relative to vYo-YoIR1 in both groups, so that D>80%vYo-YoIR1 remained similarly unchanged (-0.1 ± 0.8). Throughout the altitude sojourn, vYo-YoIR1 and D>14.4 km·h(-1) increased in parallel in AUS, so that D>80%vYo-YoIR1 remained stable in AUS (+6.0%/match, 90%CL ± 6.7); conversely D>80%vYo-YoIR1 decreased largely in BOL (-12.2%/match ± 6.2). In sea-level natives competing at high-altitude, changes in match running performance likely follow those in high-intensity running performance. Bolivian data confirm that increases in 'fitness' do not necessarily translate into greater match running performance, but rather in reduced relative exercise intensity. Key pointsWhen playing at high-altitude, players may alter their activities during matches in relation to their transient maximal physical capacities, possibly to maintain a 'tolerable' relative exercise intensity.While there is no doubt that running performance per se in not the main determinant of match outcomes (Carling, 2013), fitness levels influence relative match intensity (Buchheit et al., 2012, Mendez-Villanueva et al., 2013), which in-turn may impact on decision making and skill performance (Rampinini et al., 2008).In the context of

  3. Nutrição para os praticantes de exercício em grandes altitudes Nutritional strategy for exercising in high altitudes

    Directory of Open Access Journals (Sweden)

    Caroline Buss

    2006-02-01

    Full Text Available Quando o atleta ascende a uma grande altitude, ele é exposto a uma pressão barométrica reduzida, e os efeitos fisiológicos que acompanham estas mudanças da pressão atmosférica podem ter grande influência sobre o seu organismo e seu desempenho físico. Acredita-se que a hipóxia seja responsável pelo início de uma cascata de eventos sinalizadores que, ao final, levam à adaptação à altitude. A exposição aguda à hipóxia provoca sonolência, fadiga mental e muscular e prostração. Cefaléia, náusea e anorexia são sintomas provocados pela Doença Aguda das Montanhas, que pode ocorrer nos primeiros dias de permanência na altitude. Uma estratégia nutricional adequada é fundamental para que o organismo não sofra nenhum estresse adicional. O objetivo deste trabalho foi apresentar os principais efeitos da altitude sobre o organismo e sobre o desempenho físico, discutir e/ou sugerir recomendações nutricionais para esta situação e, se possível, apresentar uma orientação nutricional prática para o atleta na altitude. Algumas das principais conclusões encontradas foram: o consumo energético deve ser aumentado; é fundamental monitorar a quantidade de líquidos ingeridos e escolher alimentos agradáveis ao paladar, ricos em energia e nutrientes. Recomenda-se trabalhar com um nutricionista do esporte com antecedência, para que um plano alimentar individual seja elaborado e colocado em prática antes mesmo da viagem à altitude.When athletes are subject to high altitudes, they are exposed to a lower barometric pressure and the physiological effects that accompany these atmospheric pressure changes can have a strong influence on their bodies and performance. Hypoxia is thought to be responsible for triggering a cascade of signaling events that eventually leads to altitude acclimatization. Acute exposure to hypoxia causes sleepiness, mental and muscle fatigue and prostration. Headache, nausea and anorexia are some of the

  4. High altitude dermatology

    Directory of Open Access Journals (Sweden)

    G K Singh

    2017-01-01

    Full Text Available Approximately, 140 million people worldwide live permanently at high altitudes (HAs and approximately another 40 million people travel to HA area (HAA every year for reasons of occupation, sports or recreation. In India, whole of Ladakh region, part of Northwest Kashmir, Northern part of Sikkim and Tenga valley of Arunachal are considered inhabited areas of HAA. The low quantity of oxygen, high exposure of ultraviolet (UV light, very low humidity, extreme subzero temperature in winter, high wind velocity, make this region difficult for lowlanders as well as for tourists. Acute mountain sickness, HA pulmonary edema, HA cerebral edema, and thromboembolic conditions are known to occur in HA. However, enough knowledge has not been shared on dermatoses peculiar to this region. Xerosis, UV-related skin disorders (tanning, photomelanosis, acute and chronic sunburn, polymorphic light eruption, chronic actinic dermatitis, actinic cheilitis, etc., cold injuries (frostbite, chilblains, acrocyanosis, erythrocyanosis, etc. nail changes (koilonychias, airborne contact dermatitis, insect bite reaction, and skin carcinoma (basal cell carcinomas, squamous cell carcinomas, and also rarely malignant melanoma are the dermatoses seen in HAAs. Early diagnosis and knowledge of HA dermatoses may prevent serious consequences of disease and improve the quality of life for the visitors as well as for native of the place.

  5. Maximal exercise and muscle oxygen extraction in acclimatizing lowlanders and high altitude natives

    DEFF Research Database (Denmark)

    Lundby, Carsten; Sander, Mikael; van Hall, Gerrit

    2006-01-01

    , and is the focus of the present study. We have studied six lowlanders during maximal exercise at sea level (SL) and with acute (AH) exposure to 4,100 m altitude, and again after 2 (W2) and 8 weeks (W8) of altitude sojourn, where also eight high altitude native (Nat) Aymaras were studied. Fractional arterial muscle...... O(2) extraction at maximal exercise was 90.0+/-1.0% in the Danish lowlanders at sea level, and remained close to this value in all situations. In contrast to this, fractional arterial O(2) extraction was 83.2+/-2.8% in the high altitude natives, and did not change with the induction of normoxia....... The capillary oxygen conductance of the lower extremity, a measure of oxygen diffusing capacity, was decreased in the Danish lowlanders after 8 weeks of acclimatization, but was still higher than the value obtained from the high altitude natives. The values were (in ml min(-1) mmHg(-1)) 55.2+/-3.7 (SL), 48...

  6. Wilderness medicine at high altitude: recent developments in the field

    Directory of Open Access Journals (Sweden)

    Shah NM

    2015-09-01

    Full Text Available Neeraj M Shah,1 Sidra Hussain,2 Mark Cooke,3 John P O’Hara,3 Adrian Mellor3,4 1Division of Asthma, Allergy and Lung Biology, King’s College London, UK; 2School of Medicine, University College London, London, UK; 3Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK; 4Academic Department of Military Anaesthesia and Critical Care, Royal Centre for Defence Medicine, Birmingham, UK Abstract: Travel to high altitude is increasingly popular. With this comes an increased incidence of high-altitude illness and therefore an increased need to improve our strategies to prevent and accurately diagnose these. In this review, we provide a summary of recent advances of relevance to practitioners who may be advising travelers to altitude. Although the Lake Louise Score is now widely used as a diagnostic tool for acute mountain sickness (AMS, increasing evidence questions the validity of doing so, and of considering AMS as a single condition. Biomarkers, such as brain natriuretic peptide, are likely correlating with pulmonary artery systolic pressure, thus potential markers of the development of altitude illness. Established drug treatments include acetazolamide, nifedipine, and dexamethasone. Drugs with a potential to reduce the risk of developing AMS include nitrate supplements, propagators of nitric oxide, and supplemental iron. The role of exercise in the development of altitude illness remains hotly debated, and it appears that the intensity of exercise is more important than the exercise itself. Finally, despite copious studies demonstrating the value of preacclimatization in reducing the risk of altitude illness and improving performance, an optimal protocol to preacclimatize an individual remains elusive. Keywords: hypoxia, acute mountain sickness, acclimatization, biomarkers, preacclimatization

  7. Physiological Changes to the Cardiovascular System at High Altitude and Its Effects on Cardiovascular Disease.

    Science.gov (United States)

    Riley, Callum James; Gavin, Matthew

    2017-06-01

    Riley, Callum James, and Matthew Gavin. Physiological changes to the cardiovascular system at high altitude and its effects on cardiovascular disease. High Alt Med Biol. 18:102-113, 2017.-The physiological changes to the cardiovascular system in response to the high altitude environment are well understood. More recently, we have begun to understand how these changes may affect and cause detriment to cardiovascular disease. In addition to this, the increasing availability of altitude simulation has dramatically improved our understanding of the physiology of high altitude. This has allowed further study on the effect of altitude in those with cardiovascular disease in a safe and controlled environment as well as in healthy individuals. Using a thorough PubMed search, this review aims to integrate recent advances in cardiovascular physiology at altitude with previous understanding, as well as its potential implications on cardiovascular disease. Altogether, it was found that the changes at altitude to cardiovascular physiology are profound enough to have a noteworthy effect on many forms of cardiovascular disease. While often asymptomatic, there is some risk in high altitude exposure for individuals with certain cardiovascular diseases. Although controlled research in patients with cardiovascular disease was largely lacking, meaning firm conclusions cannot be drawn, these risks should be a consideration to both the individual and their physician.

  8. High altitude environmental monitoring: the SHARE project and CEOP-HE

    Science.gov (United States)

    Tartari, G.

    2009-04-01

    Mountain areas above 2,500 m a.s.l. constitute about 25% of the Earth's surface and play a fundamental role in the global water balance, while influencing global climate and atmospheric circulation systems. Several millions, including lowlanders, are directly affected by the impacts of climate change on glaciers and water resource distribution. Mountains and high altitude plateaus are subject to the highest rate of temperature increase (e.g., Tibetan Plateau) and are recognized as particularly vulnerable to the effects of climate change. In spite of this, the number of permanent monitoring sites in the major environmental networks decreases with altitude. On a sample of two hundred high altitude automatic weather stations located above 2,500 m a.s.l., less than 20% are over 4,000 m, while there are only 24 stations in the world that could be considered "complete" high altitude observatories. Furthermore, entire mountain areas are left uncovered, creating significant data gaps which make reliable modelling and forecasting nearly impossible. In response to these problems, Ev-K2-CNR has developed the project SHARE (Stations at High Altitude for Research on the Environment) with the support of the Italian government and in collaboration with UNEP. This integrated environmental monitoring and research project aims to improve knowledge on the local, regional and global consequences of climate change in mountain regions and on the influence of high elevations on climate, atmospheric circulation and hydrology. SHARE today boasts a network of 13 permanent monitoring stations between 2,165 m and 8,000 m. Affiliated researchers have produced over 150 scientific publications in atmospheric sciences, meteorology and climate, glaciology, limnology and paleolimnology and geophysics. SHARE network data is also contributed to international programs (UNEP-ABC, WMO-GAW, WCRP-GEWEX-CEOP, NASA-AERONET, ILTER, EU-EUSAAR, EU-ACCENT). Within this context, the CEOP-High Elevations (CEOP

  9. Estimation of walrus populations on sea ice with infrared imagery and aerial photography

    Science.gov (United States)

    Udevitz, M.S.; Burn, D.M.; Webber, M.A.

    2008-01-01

    Population sizes of ice-associated pinnipeds have often been estimated with visual or photographic aerial surveys, but these methods require relatively slow speeds and low altitudes, limiting the area they can cover. Recent developments in infrared imagery and its integration with digital photography could allow substantially larger areas to be surveyed and more accurate enumeration of individuals, thereby solving major problems with previous survey methods. We conducted a trial survey in April 2003 to estimate the number of Pacific walruses (Odobenus rosmarus divergens) hauled out on sea ice around St. Lawrence Island, Alaska. The survey used high altitude infrared imagery to detect groups of walruses on strip transects. Low altitude digital photography was used to determine the number of walruses in a sample of detected groups and calibrate the infrared imagery for estimating the total number of walruses. We propose a survey design incorporating this approach with satellite radio telemetry to estimate the proportion of the population in the water and additional low-level flights to estimate the proportion of the hauled-out population in groups too small to be detected in the infrared imagery. We believe that this approach offers the potential for obtaining reliable population estimates for walruses and other ice-associated pinnipeds. ?? 2007 by the Society for Marine Mammalogy.

  10. Turbojet Performance and Operation at High Altitudes with Hydrogen and Jp-4 Fuels

    Science.gov (United States)

    Fleming, W A; Kaufman, H R; Harp, J L , Jr; Chelko, L J

    1956-01-01

    Two current turbojet engines were operated with gaseous-hydrogen and JP-4 fuels at very high altitudes and a simulated Mach number of 0.8. With gaseous hydrogen as the fuel stable operation was obtained at altitudes up to the facility limit of about 90,000 feet and the specific fuel consumption was only 40 percent of that with JP-4 fuel. With JP-4 as the fuel combustion was unstable at altitudes above 60,000 to 65,000 feet and blowout limits were reached at 75,000 to 80,000 feet. Over-all performance, component efficiencies, and operating range were reduced considerable at very high altitudes with both fuels.

  11. Metabolic characteristics and response to high altitude in Phrynocephalus erythrurus (Lacertilia: Agamidae, a lizard dwell at altitudes higher than any other living lizards in the world.

    Directory of Open Access Journals (Sweden)

    Xiaolong Tang

    Full Text Available Metabolic response to high altitude remains poorly explored in reptiles. In the present study, the metabolic characteristics of Phrynocephaluserythrurus (Lacertilia: Agamidae, which inhabits high altitudes (4500 m and Phrynocephalusprzewalskii (Lacertilia: Agamidae, which inhabits low altitudes, were analysed to explore the metabolic regulatory strategies for lizards living at high-altitude environments. The results indicated that the mitochondrial respiratory rates of P. erythrurus were significantly lower than those of P. przewalskii, and that proton leak accounts for 74~79% of state 4 and 7~8% of state3 in P. erythrurus vs. 43~48% of state 4 and 24~26% of state3 in P. przewalskii. Lactate dehydrogenase (LDH activity in P. erythrurus was lower than in P. przewalskii, indicating that at high altitude the former does not, relatively, have a greater reliance on anaerobic metabolism. A higher activity related to β-hydroxyacyl coenzyme A dehydrogenase (HOAD and the HOAD/citrate synthase (CS ratio suggested there was a possible higher utilization of fat in P. erythrurus. The lower expression of PGC-1α and PPAR-γ in P. erythrurus suggested their expression was not influenced by cold and low PO2 at high altitude. These distinct characteristics of P. erythrurus are considered to be necessary strategies in metabolic regulation for living at high altitude and may effectively compensate for the negative influence of cold and low PO2.

  12. The GRAD high-altitude balloon flight over Antarctica

    International Nuclear Information System (INIS)

    Eichhorn, G.; Coldwell, R.L.; Dunnam, F.E.; Rester, A.C.; Trombka, J.I.; Starr, R.; Lasche, G.P.

    1989-01-01

    The Gamma Ray Advanced Detector(GRAD) consists of a n-type germanium detector inside an active bismuth-germanate Compton and charged particle shield with additional active plastic shielding across the aperture. It will be flown on a high altitude balloon at 36 km altitude at a latitude of 78 degree S over Antarctica for observations of gamma radiation emitted by the radioactive decay of 56 Co in the Supernova SN1987A, for assessment of the performance of bismuth-germanate scintillation material in the radiation environment of near space, for gathering information on the gamma-ray background over Antarctica, and for testing fault-tolerant software

  13. A marine biogenic source of atmospheric ice-nucleating particles

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, T. W.; Ladino, L. A.; Alpert, Peter A.; Breckels, M. N.; Brooks, I. M.; Browse, J.; Burrows, Susannah M.; Carslaw, K. S.; Huffman, J. A.; Judd, C.; Kilthau, W. P.; Mason, R. H.; McFiggans, Gordon; Miller, L. A.; Najera, J.; Polishchuk, E. A.; Rae, S.; Schiller, C. L.; Si, M.; Vergara Temprado, J.; Whale, Thomas; Wong, J P S; Wurl, O.; Yakobi-Hancock, J. D.; Abbatt, JPD; Aller, Josephine Y.; Bertram, Allan K.; Knopf, Daniel A.; Murray, Benjamin J.

    2015-09-09

    The formation of ice in clouds is facilitated by the presence of airborne ice nucleating particles1,2. Sea spray is one of the major global sources of atmospheric particles, but it is unclear to what extent these particles are capable of nucleating ice3–11. Here we show that material in the sea surface microlayer, which is enriched in surface active organic material representative of that found in sub-micron sea- spray aerosol12–21, nucleates ice under conditions that occur in mixed-phase clouds and high-altitude ice clouds. The ice active material is likely biogenic and is less than ~0.2 ?m in size. We also show that organic material (exudate) released by a common marine diatom nucleates ice when separated from cells and propose that organic material associated with phytoplankton cell exudates are a candidate for the observed ice nucleating ability of the microlayer samples. By combining our measurements with global model simulations of marine organic aerosol, we show that ice nucleating particles of marine origin are dominant in remote marine environments, such as the Southern Ocean, the North Pacific and the North Atlantic.

  14. Airborne observations and simulations of three-dimensional radiative interactions between Arctic boundary layer clouds and ice floes

    Directory of Open Access Journals (Sweden)

    M. Schäfer

    2015-07-01

    Full Text Available Based on airborne spectral imaging observations, three-dimensional (3-D radiative effects between Arctic boundary layer clouds and highly variable Arctic surfaces were identified and quantified. A method is presented to discriminate between sea ice and open water under cloudy conditions based on airborne nadir reflectivity γλ measurements in the visible spectral range. In cloudy cases the transition of γλ from open water to sea ice is not instantaneous but horizontally smoothed. In general, clouds reduce γλ above bright surfaces in the vicinity of open water, while γλ above open sea is enhanced. With the help of observations and 3-D radiative transfer simulations, this effect was quantified to range between 0 and 2200 m distance to the sea ice edge (for a dark-ocean albedo of αwater = 0.042 and a sea-ice albedo of αice = 0.91 at 645 nm wavelength. The affected distance Δ L was found to depend on both cloud and sea ice properties. For a low-level cloud at 0–200 m altitude, as observed during the Arctic field campaign VERtical Distribution of Ice in Arctic clouds (VERDI in 2012, an increase in the cloud optical thickness τ from 1 to 10 leads to a decrease in Δ L from 600 to 250 m. An increase in the cloud base altitude or cloud geometrical thickness results in an increase in Δ L; for τ = 1/10 Δ L = 2200 m/1250 m in case of a cloud at 500–1000 m altitude. To quantify the effect for different shapes and sizes of ice floes, radiative transfer simulations were performed with various albedo fields (infinitely long straight ice edge, circular ice floes, squares, realistic ice floe field. The simulations show that Δ L increases with increasing radius of the ice floe and reaches maximum values for ice floes with radii larger than 6 km (500–1000 m cloud altitude, which matches the results found for an infinitely long, straight ice edge. Furthermore, the influence of these 3-D radiative effects on the retrieved cloud optical

  15. Airborne observations and simulations of three-dimensional radiative interactions between Arctic boundary layer clouds and ice floes

    Science.gov (United States)

    Schäfer, M.; Bierwirth, E.; Ehrlich, A.; Jäkel, E.; Wendisch, M.

    2015-07-01

    Based on airborne spectral imaging observations, three-dimensional (3-D) radiative effects between Arctic boundary layer clouds and highly variable Arctic surfaces were identified and quantified. A method is presented to discriminate between sea ice and open water under cloudy conditions based on airborne nadir reflectivity γλ measurements in the visible spectral range. In cloudy cases the transition of γλ from open water to sea ice is not instantaneous but horizontally smoothed. In general, clouds reduce γλ above bright surfaces in the vicinity of open water, while γλ above open sea is enhanced. With the help of observations and 3-D radiative transfer simulations, this effect was quantified to range between 0 and 2200 m distance to the sea ice edge (for a dark-ocean albedo of αwater = 0.042 and a sea-ice albedo of αice = 0.91 at 645 nm wavelength). The affected distance Δ L was found to depend on both cloud and sea ice properties. For a low-level cloud at 0-200 m altitude, as observed during the Arctic field campaign VERtical Distribution of Ice in Arctic clouds (VERDI) in 2012, an increase in the cloud optical thickness τ from 1 to 10 leads to a decrease in Δ L from 600 to 250 m. An increase in the cloud base altitude or cloud geometrical thickness results in an increase in Δ L; for τ = 1/10 Δ L = 2200 m/1250 m in case of a cloud at 500-1000 m altitude. To quantify the effect for different shapes and sizes of ice floes, radiative transfer simulations were performed with various albedo fields (infinitely long straight ice edge, circular ice floes, squares, realistic ice floe field). The simulations show that Δ L increases with increasing radius of the ice floe and reaches maximum values for ice floes with radii larger than 6 km (500-1000 m cloud altitude), which matches the results found for an infinitely long, straight ice edge. Furthermore, the influence of these 3-D radiative effects on the retrieved cloud optical properties was investigated

  16. Coca: High Altitude Remedy of the Ancient Incas.

    Science.gov (United States)

    Biondich, Amy Sue; Joslin, Jeremy D

    2015-12-01

    The use of coca leaf for medicinal purposes is a centuries-old tradition of the native peoples of South America. Coca products are thought by many laypersons to provide risk-free benefits to users participating in strenuous activities at high altitude. Physiologic studies of coca have increased understanding of its possible mechanism of action as well as its potential impact on high altitude activities. This present work explores the role of coca throughout the history of the Andean peoples and explores whether this ancient remedy has a place in modern medicine. A focused summary of research articles with particular relevance to the field of wilderness medicine is also included to better provide the reader with lessons not only from history but also from another culture. Copyright © 2015 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

  17. White Mountain Research Station: 25 years of high-altitude research. [organization and functions of test facility for high altitude research

    Science.gov (United States)

    Pace, N.

    1973-01-01

    The organization and functions of a test facility for conducting research projects at high altitudes are discussed. The projects conducted at the facility include the following: (1) bird physiology, (2) cardiorespiratory physiology, (3) endocrinological studies, (4) neurological studies, (5) metabolic studies, and (6) geological studies.

  18. High Altitude Warfare: The Kargil Conflict and the Future

    National Research Council Canada - National Science Library

    Acosta, Marcus

    2003-01-01

    The unique combination of thin air, freezing temperatures, and mountainous terrain that forms the high altitude environment has resisted advances in military technology for centuries, The emergence...

  19. Lens autofluorescence is not increased at high altitude

    DEFF Research Database (Denmark)

    Kessel, Line; Kofoed, Peter Kristian; Zubieta-Calleja, Gustavo

    2010-01-01

    in Denmark. RESULTS: No significant differences in lens fluorescence or transmittance were found between Bolivian and Danish volunteers. CONCLUSION: Age-corrected lens fluorescence and transmittance were comparable for healthy participants living at high altitude near the equator and healthy volunteers...

  20. Solar Cell Short Circuit Current Errors and Uncertainties During High Altitude Calibrations

    Science.gov (United States)

    Snyder, David D.

    2012-01-01

    High altitude balloon based facilities can make solar cell calibration measurements above 99.5% of the atmosphere to use for adjusting laboratory solar simulators. While close to on-orbit illumination, the small attenuation to the spectra may result in under measurements of solar cell parameters. Variations of stratospheric weather, may produce flight-to-flight measurement variations. To support the NSCAP effort, this work quantifies some of the effects on solar cell short circuit current (Isc) measurements on triple junction sub-cells. This work looks at several types of high altitude methods, direct high altitude meas urements near 120 kft, and lower stratospheric Langley plots from aircraft. It also looks at Langley extrapolation from altitudes above most of the ozone, for potential small balloon payloads. A convolution of the sub-cell spectral response with the standard solar spectrum modified by several absorption processes is used to determine the relative change from AMO, lscllsc(AMO). Rayleigh scattering, molecular scatterin g from uniformly mixed gases, Ozone, and water vapor, are included in this analysis. A range of atmosph eric pressures are examined, from 0. 05 to 0.25 Atm to cover the range of atmospheric altitudes where solar cell calibrations a reperformed. Generally these errors and uncertainties are less than 0.2%

  1. Seasonal variations in the sources of natural and anthropogenic lead deposited at the East Rongbuk Glacier in the high-altitude Himalayas

    International Nuclear Information System (INIS)

    Burn-Nunes, Laurie; Vallelonga, Paul; Lee, Khanghyun; Hong, Sungmin; Burton, Graeme; Hou, Shugui; Moy, Andrew; Edwards, Ross; Loss, Robert; Rosman, Kevin

    2014-01-01

    Lead (Pb) isotopic compositions and concentrations, and barium (Ba) and indium (In) concentrations have been analysed at sub-annual resolution in three sections from a < 110 m ice core dated to the 18th and 20th centuries, as well as snow pit samples dated to 2004/2005, recovered from the East Rongbuk Glacier in the high-altitude Himalayas. Ice core sections indicate that atmospheric chemistry prior to ∼ 1953 was controlled by mineral dust inputs, with no discernible volcanic or anthropogenic contributions. Eighteenth century monsoon ice core chemistry is indicative of dominant contributions from local Himalayan sources; non-monsoon ice core chemistry is linked to contributions from local (Himalayan), regional (Indian/Thar Desert) and long-range (North Africa, Central Asia) sources. Twentieth century monsoon and non-monsoon ice core data demonstrate similar seasonal sources of mineral dust, however with a transition to less-radiogenic isotopic signatures that suggests local and regional climate/environmental change. The snow pit record demonstrates natural and anthropogenic contributions during both seasons, with increased anthropogenic influence during non-monsoon times. Monsoon anthropogenic inputs are most likely sourced to South/South-East Asia and/or India, whereas non-monsoon anthropogenic inputs are most likely sourced to India and Central Asia. - Highlights: • Pb isotopes in ice and snow show seasonality in Mt Everest atmospheric chemistry. • Local (Himalayan) mineral dust inputs are present year round. • Regional and long-range mineral dust inputs are evident during non-monsoon times. • Snow samples indicate increased anthropogenic inputs during non-monsoon times. • Anthropogenic inputs are linked with Indian, South Asian and Central Asian sources

  2. Seasonal variations in the sources of natural and anthropogenic lead deposited at the East Rongbuk Glacier in the high-altitude Himalayas

    Energy Technology Data Exchange (ETDEWEB)

    Burn-Nunes, Laurie, E-mail: L.Nunes@curtin.edu.au [Department of Imaging and Applied Physics, Curtin University, GPO Box U 1987, Perth 6845, Western Australia (Australia); Vallelonga, Paul [Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen Ø (Denmark); Lee, Khanghyun [Environmental Measurement and Analysis Center, National Institute of Environmental Research, Environmental Research Complex, Kyungseo-dong, Seo-gu, Incheon 404-170 (Korea, Republic of); Hong, Sungmin [Department of Ocean Sciences, Inha University, 100 Inha-ro, Nam-gu, Incheon 402-751 (Korea, Republic of); Burton, Graeme [Department of Imaging and Applied Physics, Curtin University, GPO Box U 1987, Perth 6845, Western Australia (Australia); Hou, Shugui [Key Laboratory of Coast and Island development of Ministry of Education, School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210093 (China); Moy, Andrew [Department of the Environment, Australian Antarctic Division, Channel Highway, Kingston 7050, Tasmania (Australia); Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania, Private Bag 80, Hobart 7001, Tasmania (Australia); Edwards, Ross; Loss, Robert; Rosman, Kevin [Department of Imaging and Applied Physics, Curtin University, GPO Box U 1987, Perth 6845, Western Australia (Australia)

    2014-07-01

    Lead (Pb) isotopic compositions and concentrations, and barium (Ba) and indium (In) concentrations have been analysed at sub-annual resolution in three sections from a < 110 m ice core dated to the 18th and 20th centuries, as well as snow pit samples dated to 2004/2005, recovered from the East Rongbuk Glacier in the high-altitude Himalayas. Ice core sections indicate that atmospheric chemistry prior to ∼ 1953 was controlled by mineral dust inputs, with no discernible volcanic or anthropogenic contributions. Eighteenth century monsoon ice core chemistry is indicative of dominant contributions from local Himalayan sources; non-monsoon ice core chemistry is linked to contributions from local (Himalayan), regional (Indian/Thar Desert) and long-range (North Africa, Central Asia) sources. Twentieth century monsoon and non-monsoon ice core data demonstrate similar seasonal sources of mineral dust, however with a transition to less-radiogenic isotopic signatures that suggests local and regional climate/environmental change. The snow pit record demonstrates natural and anthropogenic contributions during both seasons, with increased anthropogenic influence during non-monsoon times. Monsoon anthropogenic inputs are most likely sourced to South/South-East Asia and/or India, whereas non-monsoon anthropogenic inputs are most likely sourced to India and Central Asia. - Highlights: • Pb isotopes in ice and snow show seasonality in Mt Everest atmospheric chemistry. • Local (Himalayan) mineral dust inputs are present year round. • Regional and long-range mineral dust inputs are evident during non-monsoon times. • Snow samples indicate increased anthropogenic inputs during non-monsoon times. • Anthropogenic inputs are linked with Indian, South Asian and Central Asian sources.

  3. Right ventricular morphology and function in chronic obstructive pulmonary disease patients living at high altitude.

    Science.gov (United States)

    Güvenç, Tolga Sinan; Erer, Hatice Betül; Kul, Seref; Perinçek, Gökhan; Ilhan, Sami; Sayar, Nurten; Yıldırım, Binnaz Zeynep; Doğan, Coşkun; Karabağ, Yavuz; Balcı, Bahattin; Eren, Mehmet

    2013-01-01

    Pulmonary vasculature is affected in patients with chronic pulmonary obstructive disease (COPD). As a result of increased pulmonary resistance, right ventricular morphology and function are altered in COPD patients. High altitude and related hypoxia causes pulmonary vasoconstriction, thereby affecting the right ventricle. We aimed to investigate the combined effects of COPD and altitude-related chronic hypoxia on right ventricular morphology and function. Forty COPD patients living at high altitude (1768 m) and 41 COPD patients living at sea level were enrolled in the study. All participants were diagnosed as COPD by a pulmonary diseases specialist depending on symptoms, radiologic findings and pulmonary function test results. Detailed two-dimensional echocardiography was performed by a cardiologist at both study locations. Oxygen saturation and mean pulmonary artery pressure were higher in the high altitude group. Right ventricular end diastolic diameter, end systolic diameter, height and end systolic area were significantly higher in the high altitude group compared to the sea level group. Parameters of systolic function, including tricuspid annular systolic excursion, systolic velocity of tricuspid annulus and right ventricular isovolumic acceleration were similar between groups, while fractional area change was significantly higher in the sea level groups compared to the high altitude group. Indices of diastolic function and myocardial performance index were similar between groups. An increase in mean pulmonary artery pressure and right ventricular dimensions are observed in COPD patients living at high altitude. Despite this increase, systolic and diastolic functions of the right ventricle, as well as global right ventricular performance are similar in COPD patients living at high altitude and sea level. Altitude-related adaptation to chronic hypoxia could explain these findings. Copyright © 2012 Australian and New Zealand Society of Cardiac and Thoracic

  4. The evolution of Titan's high-altitude aerosols under ultraviolet irradiation

    Science.gov (United States)

    Carrasco, Nathalie; Tigrine, Sarah; Gavilan, Lisseth; Nahon, Laurent; Gudipati, Murthy S.

    2018-04-01

    The Cassini-Huygens space mission revealed that Titan's thick brownish haze is initiated high in the atmosphere at an altitude of about 1,000 km, before a slow transportation down to the surface. Close to the surface, at altitudes below 130 km, the Huygens probe provided information on the chemical composition of the haze. So far, we have not had insights into the possible photochemical evolution of the aerosols making up the haze during their descent. Here, we address this atmospheric aerosol aging process, simulating in the laboratory how solar vacuum ultraviolet irradiation affects the aerosol optical properties as probed by infrared spectroscopy. An important evolution was found that could explain the apparent contradiction between the nitrogen-poor infrared spectroscopic signature observed by Cassini below 600 km of altitude in Titan's atmosphere and a high nitrogen content as measured by the aerosol collector and pyrolyser of the Huygens probe at the surface of Titan.

  5. High altitude and hemoglobin function in the vultures Gyps rueppelli and Aegypius monachus

    DEFF Research Database (Denmark)

    Weber, Roy E.; Hiebl, Inge; Braunitzer, Gerhard

    1988-01-01

    Functional characteristics of the stripped composite hemoglobins (Hbs) of lhevultures Gyps rueppellii and Aegypills monachus that can fly at extremely high altitudes, and of component Hbs of G. rueppellii are reported, in relation to influences of pH, temperalure and inositol hexaphosphate. G...... structures of the constituent polypeptide chains to trace molecular adaptations to high-altitude respiration, and to physiological factors (pulmonary hypoxia and hypocapnia, body temperature shifts, and lung and nasal gas and heat exchange) to discern their possible survival value at altitudes of 11300 m....

  6. Nutritional Strategies for the Preservation of Fat Free Mass at High Altitude

    Directory of Open Access Journals (Sweden)

    Stacie L. Wing-Gaia

    2014-02-01

    Full Text Available Exposure to extreme altitude presents many physiological challenges. In addition to impaired physical and cognitive function, energy imbalance invariably occurs resulting in weight loss and body composition changes. Weight loss, and in particular, loss of fat free mass, combined with the inherent risks associated with extreme environments presents potential performance, safety, and health risks for those working, recreating, or conducting military operations at extreme altitude. In this review, contributors to muscle wasting at altitude are highlighted with special emphasis on protein turnover. The article will conclude with nutritional strategies that may potentially attenuate loss of fat free mass during high altitude exposure.

  7. Iron supplementation at high altitudes induces inflammation and oxidative injury to lung tissues in rats

    Energy Technology Data Exchange (ETDEWEB)

    Salama, Samir A., E-mail: salama.3@buckeyemail.osu.edu [High Altitude Research Center, Taif University, Al-Haweiah, Taif 21974 (Saudi Arabia); Department of Biochemistry, Faculty of Pharmacy, Al-Azhar University, Cairo 11751 (Egypt); Department of Pharmacology and GTMR Unit, College of Clinical Pharmacy, Taif University, Al-Haweiah, Taif 21974 (Saudi Arabia); Omar, Hany A. [Department of Pharmacology, Faculty of Pharmacy, Beni-Suef University, Beni-Suef 62514 (Egypt); Maghrabi, Ibrahim A. [Department of Clinical Pharmacy, College of Clinical Pharmacy, Taif University, Al-Haweiah, Taif 21974 (Saudi Arabia); AlSaeed, Mohammed S. [Department of Surgery, College of Medicine, Taif University, Al-Haweiah, Taif 21974 (Saudi Arabia); EL-Tarras, Adel E. [High Altitude Research Center, Taif University, Al-Haweiah, Taif 21974 (Saudi Arabia)

    2014-01-01

    Exposure to high altitudes is associated with hypoxia and increased vulnerability to oxidative stress. Polycythemia (increased number of circulating erythrocytes) develops to compensate the high altitude associated hypoxia. Iron supplementation is, thus, recommended to meet the demand for the physiological polycythemia. Iron is a major player in redox reactions and may exacerbate the high altitudes-associated oxidative stress. The aim of this study was to explore the potential iron-induced oxidative lung tissue injury in rats at high altitudes (6000 ft above the sea level). Iron supplementation (2 mg elemental iron/kg, once daily for 15 days) induced histopathological changes to lung tissues that include severe congestion, dilatation of the blood vessels, emphysema in the air alveoli, and peribronchial inflammatory cell infiltration. The levels of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α), lipid peroxidation product and protein carbonyl content in lung tissues were significantly elevated. Moreover, the levels of reduced glutathione and total antioxidant capacity were significantly reduced. Co-administration of trolox, a water soluble vitamin E analog (25 mg/kg, once daily for the last 7 days of iron supplementation), alleviated the lung histological impairments, significantly decreased the pro-inflammatory cytokines, and restored the oxidative stress markers. Together, our findings indicate that iron supplementation at high altitudes induces lung tissue injury in rats. This injury could be mediated through excessive production of reactive oxygen species and induction of inflammatory responses. The study highlights the tissue injury induced by iron supplementation at high altitudes and suggests the co-administration of antioxidants such as trolox as protective measures. - Highlights: • Iron supplementation at high altitudes induced lung histological changes in rats. • Iron induced oxidative stress in lung tissues of rats at high altitudes. • Iron

  8. Iron supplementation at high altitudes induces inflammation and oxidative injury to lung tissues in rats

    International Nuclear Information System (INIS)

    Salama, Samir A.; Omar, Hany A.; Maghrabi, Ibrahim A.; AlSaeed, Mohammed S.; EL-Tarras, Adel E.

    2014-01-01

    Exposure to high altitudes is associated with hypoxia and increased vulnerability to oxidative stress. Polycythemia (increased number of circulating erythrocytes) develops to compensate the high altitude associated hypoxia. Iron supplementation is, thus, recommended to meet the demand for the physiological polycythemia. Iron is a major player in redox reactions and may exacerbate the high altitudes-associated oxidative stress. The aim of this study was to explore the potential iron-induced oxidative lung tissue injury in rats at high altitudes (6000 ft above the sea level). Iron supplementation (2 mg elemental iron/kg, once daily for 15 days) induced histopathological changes to lung tissues that include severe congestion, dilatation of the blood vessels, emphysema in the air alveoli, and peribronchial inflammatory cell infiltration. The levels of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α), lipid peroxidation product and protein carbonyl content in lung tissues were significantly elevated. Moreover, the levels of reduced glutathione and total antioxidant capacity were significantly reduced. Co-administration of trolox, a water soluble vitamin E analog (25 mg/kg, once daily for the last 7 days of iron supplementation), alleviated the lung histological impairments, significantly decreased the pro-inflammatory cytokines, and restored the oxidative stress markers. Together, our findings indicate that iron supplementation at high altitudes induces lung tissue injury in rats. This injury could be mediated through excessive production of reactive oxygen species and induction of inflammatory responses. The study highlights the tissue injury induced by iron supplementation at high altitudes and suggests the co-administration of antioxidants such as trolox as protective measures. - Highlights: • Iron supplementation at high altitudes induced lung histological changes in rats. • Iron induced oxidative stress in lung tissues of rats at high altitudes. • Iron

  9. Ancient Biomolecules from Deep Ice Cores Reveal a Forested Southern Greenland

    Science.gov (United States)

    Willerslev, Eske; Cappellini, Enrico; Boomsma, Wouter; Nielsen, Rasmus; Hebsgaard, Martin B.; Brand, Tina B.; Hofreiter, Michael; Bunce, Michael; Poinar, Hendrik N.; Dahl-Jensen, Dorthe; Johnsen, Sigfus; Steffensen, Jørgen Peder; Bennike, Ole; Schwenninger, Jean-Luc; Nathan, Roger; Armitage, Simon; de Hoog, Cees-Jan; Alfimov, Vasily; Christl, Marcus; Beer, Juerg; Muscheler, Raimund; Barker, Joel; Sharp, Martin; Penkman, Kirsty E.H.; Haile, James; Taberlet, Pierre; Gilbert, M. Thomas P.; Casoli, Antonella; Campani, Elisa; Collins, Matthew J.

    2009-01-01

    One of the major difficulties in paleontology is the acquisition of fossil data from the 10% of Earth’s terrestrial surface that is covered by thick glaciers and ice sheets. Here we reveal that DNA and amino acids from buried organisms can be recovered from the basal sections of deep ice cores and allow reconstructions of past flora and fauna. We show that high altitude southern Greenland, currently lying below more than two kilometers of ice, was once inhabited by a diverse array of conifer trees and insects that may date back more than 450 thousand years. The results provide the first direct evidence in support of a forested southern Greenland and suggest that many deep ice cores may contain genetic records of paleoenvironments in their basal sections. PMID:17615355

  10. An extremely high altitude plume seen at Mars morning terminator

    Science.gov (United States)

    Sanchez-Lavega, Agustin; Garcia-Muñoz, Antonio; Garcia-Melendo, Enrique; Perez-Hoyos, Santiago; Gomez-Forrellad, Josep M.; Pellier, Christophe; Delcroix, Marc; Lopez-Valverde, Miguel Angel; Gonzalez-Galindo, Francisco; Jaeschke, Wayne; Parker, Donald C.; Phillips, James H.; Peach, Damian

    2014-11-01

    We report the occurrence in March and April 2012 of two bright very high altitude plumes at the Martian terminator at 250 km or more above the surface, thus well into the ionosphere and bordering on the exosphere. They were located at about 195 deg West longitude and -45 deg latitude (at Terra Cimmeria) and lasted for about 10 days. The features showed day-to-day variability, and were seen at the morning terminator but not at the evening limb, which indicates rapid evolution in less than 10 hours and a cyclic behavior. Photometric measurements are used to explore two possible scenarios to explain their nature. If the phenomenon is due to suspended particles (dust, CO2 or H2O ice clouds) reflecting solar radiation, the mean size is about 0.1 microns with a nadir optical depth > 0.06. Alternatively, the plume could be auroral emission above a region with a strong magnetic anomaly and where aurora has previously been detected. Importantly, both explanations defy our current understanding of the Mars upper atmosphere.AcknowledgementsThis work was supported by the Spanish MINECO projects AYA2012-36666 with FEDER support, CONSOLIDER program ASTROMOL CSD2009-00038 and AYA2011-30613-CO2-1. Grupos Gobierno Vasco IT765-13 and UPV/EHU UFI11/55.

  11. Effects of erythrocyte infusion on VO2max at high altitude

    DEFF Research Database (Denmark)

    Young, Jette Feveile; Sawka, M N; Muza, S R

    1996-01-01

    This study investigated whether autologous erythrocyte infusion would ameliorate the decrement in maximal O2 uptake (VO2max) experienced by lowlanders when they ascend to high altitude. VO2max was measured in 16 men (treadmill running) at sea level (SL) and on the 1st (HA1) and 9th (HA9) days...... of high-altitude (4,300 m) residence. After VO2max was measured at SL, subjects were divided into two matched groups (n = 8). Twenty-four hours before ascent to high altitude, the experimental group received a 700-ml infusion of autologous erythrocytes and saline (42% hematocrit), whereas the control...... group received only saline. The VO2max of erythrocyte-infused [54 +/- 1 (SE) ml.kg-1.min-1] and control subjects (52 +/- 2 ml.kg-1.min-1) did not differ at SL before infusion. The decrement in VO2max on HA1 did not differ between groups, averaging 26% overall, despite higher (P

  12. Natural Selection on Genes Related to Cardiovascular Health in High-Altitude Adapted Andeans.

    Science.gov (United States)

    Crawford, Jacob E; Amaru, Ricardo; Song, Jihyun; Julian, Colleen G; Racimo, Fernando; Cheng, Jade Yu; Guo, Xiuqing; Yao, Jie; Ambale-Venkatesh, Bharath; Lima, João A; Rotter, Jerome I; Stehlik, Josef; Moore, Lorna G; Prchal, Josef T; Nielsen, Rasmus

    2017-11-02

    The increase in red blood cell mass (polycythemia) due to the reduced oxygen availability (hypoxia) of residence at high altitude or other conditions is generally thought to be beneficial in terms of increasing tissue oxygen supply. However, the extreme polycythemia and accompanying increased mortality due to heart failure in chronic mountain sickness most likely reduces fitness. Tibetan highlanders have adapted to high altitude, possibly in part via the selection of genetic variants associated with reduced polycythemic response to hypoxia. In contrast, high-altitude-adapted Quechua- and Aymara-speaking inhabitants of the Andean Altiplano are not protected from high-altitude polycythemia in the same way, yet they exhibit other adaptive features for which the genetic underpinnings remain obscure. Here, we used whole-genome sequencing to scan high-altitude Andeans for signals of selection. The genes showing the strongest evidence of selection-including BRINP3, NOS2, and TBX5-are associated with cardiovascular development and function but are not in the response-to-hypoxia pathway. Using association mapping, we demonstrated that the haplotypes under selection are associated with phenotypic variations related to cardiovascular health. We hypothesize that selection in response to hypoxia in Andeans could have vascular effects and could serve to mitigate the deleterious effects of polycythemia rather than reduce polycythemia itself. Copyright © 2017. Published by Elsevier Inc.

  13. Thoracic skeletal morphology and high-altitude hypoxia in Andean prehistory.

    Science.gov (United States)

    Weinstein, Karen J

    2007-09-01

    Living humans from the highland Andes exhibit antero-posteriorly and medio-laterally enlarged chests in response to high-altitude hypoxia. This study hypothesizes that morphological responses to high-altitude hypoxia should also be evident in pre-Contact Andean groups. Thoracic skeletal morphology in four groups of human skeletons (N = 347) are compared: two groups from coastal regions (Ancón, Peru, n = 79 and Arica, Chile, n = 123) and two groups from high altitudes (San Pedro de Atacama, Chile, n = 102 and Machu Picchu and Cuzco, Peru, n = 43). Osteometric variables that represent proportions of chest width and depth include sternal and clavicular lengths and breadths and rib length, curvature, and area. Each variable was measured relative to body size, transformed into logarithmic indices, and compared across sex-specific groups using ANOVA and Tukey multiple comparison tests. Atacama highlanders have the largest sternal and clavicular proportions and ribs with the greatest area and least amount of curvature, features that suggest an antero-posteriorly deep and mediolaterally wide thoracic skeleton. Ancón lowlanders exhibit proportions indicating narrower and shallower chests. Machu Picchu and Cuzco males cluster with the other highland group in rib curvature and area at the superior levels of the thorax, whereas chest proportions in Machu Picchu and Cuzco females resemble those of lowlanders. The variation in Machu Picchu and Cuzco males and females is interpreted as the result of population migrations. The presence of morphological traits indicative of enlarged chests in some highland individuals suggests that high-altitude hypoxia was an environmental stressor shaping the biology of highland Andean groups during the pre-Contact period. (c) 2007 Wiley-Liss, Inc.

  14. Metabolic Effects of High Altitude Trekking in Patients With Type 2 Diabetes

    NARCIS (Netherlands)

    de Mol, Pieter; Fokkert, Marion J.; de Vries, Suzanna T.; de Koning, Eelco J. P.; Dikkeschei, Bert D.; Gans, Rijnold O. B.; Tack, Cees J.; Bilo, Henk J. G.

    2012-01-01

    OBJECTIVE-Limited information is available regarding the metabolic effects of high altitude trekking in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS-Thirteen individuals with type 2 diabetes took part, in a 12-day expedition to the summit of Mount Toubkal (altitude, 4,167 m), Morocco,

  15. Metabolic effects of high altitude trekking in patients with type 2 diabetes

    NARCIS (Netherlands)

    Mol, P. de; Fokkert, M.J.; Vries, S.T. de; Koning, E.J. de; Dikkeschei, B.D.; Gans, R.O.; Tack, C.J.J.; Bilo, H.J.

    2012-01-01

    OBJECTIVE Limited information is available regarding the metabolic effects of high altitude trekking in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS Thirteen individuals with type 2 diabetes took part in a 12-day expedition to the summit of Mount Toubkal (altitude, 4,167 m), Morocco,

  16. Hyperbaric oxygen preconditioning protects against traumatic brain injury at high altitude.

    Science.gov (United States)

    Hu, S L; Hu, R; Li, F; Liu, Z; Xia, Y Z; Cui, G Y; Feng, H

    2008-01-01

    Recent studies have shown that preconditioning with hyperbaric oxygen (HBO) can reduce ischemic and hemorrhagic brain injury. We investigated effects of HBO preconditioning on traumatic brain injury (TBI) at high altitude and examined the role of matrix metalloproteinase-9 (MMP-9) in such protection. Rats were randomly divided into 3 groups: HBO preconditioning group (HBOP; n = 13), high-altitude group (HA; n = 13), and high-altitude sham operation group (HASO; n = 13). All groups were subjected to head trauma by weight-drop device, except for HASO group. HBOP rats received 5 sessions of HBO preconditioning (2.5 ATA, 100% oxygen, 1 h daily) and then were kept in hypobaric chamber at 0.6 ATA (to simulate pressure at 4000m altitude) for 3 days before operation. HA rats received control pretreatment (1 ATA, room air, 1 h daily), then followed the same procedures as HBOP group. HASO rats were subjected to skull opening only without brain injury. Twenty-four hours after TBI, 7 rats from each group were examined for neurological function and brain water content; 6 rats from each group were killed for analysis by H&E staining and immunohistochemistry. Neurological outcome in HBOP group (0.71 +/- 0.49) was better than HA group (1.57 +/- 0.53; p < 0.05). Preconditioning with HBO significantly reduced percentage of brain water content (86.24 +/- 0.52 vs. 84.60 +/- 0.37; p < 0.01). Brain morphology and structure seen by light microscopy was diminished in HA group, while fewer pathological injuries occurred in HBOP group. Compared to HA group, pretreatment with HBO significantly reduced the number of MMP-9-positive cells (92.25 +/- 8.85 vs. 74.42 +/- 6.27; p < 0.01). HBO preconditioning attenuates TBI in rats at high altitude. Decline in MMP-9 expression may contribute to HBO preconditioning-induced protection of brain tissue against TBI.

  17. Increased Cardiometabolic Risk and Worsening Hypoxemia at High Altitude.

    Science.gov (United States)

    Miele, Catherine H; Schwartz, Alan R; Gilman, Robert H; Pham, Luu; Wise, Robert A; Davila-Roman, Victor G; Jun, Jonathan C; Polotsky, Vsevolod Y; Miranda, J Jaime; Leon-Velarde, Fabiola; Checkley, William

    2016-06-01

    Miele, Catherine H., Alan R. Schwartz, Robert H. Gilman, Luu Pham, Robert A. Wise, Victor G. Davila-Roman, Jonathan C. Jun, Vsevolod Y. Polotsky, J. Jaime Miranda, Fabiola Leon-Velarde, and William Checkley. Increased cardiometabolic risk and worsening hypoxemia at high altitude. High Alt Med Biol. 17:93-100, 2016.-Metabolic syndrome, insulin resistance, diabetes, and dyslipidemia are associated with an increased risk of cardiovascular disease. While excessive erythrocytosis is associated with cardiovascular complications, it is unclear how worsening hypoxemia of any degree affects cardiometabolic risk factors in high-altitude populations. We studied the relationship between daytime resting oxyhemoglobin saturation and cardiometabolic risk factors in adult participants living in Puno, Peru (3825 m above sea level). We used multivariable logistic regression models to study the relationship between having a lower oxyhemoglobin saturation and markers of cardiometabolic risk. Nine hundred and fifty-four participants (mean age 55 years, 52% male) had information available on pulse oximetry and markers of cardiometabolic risk. Average oxyhemoglobin saturation was 90% (interquartile range 88%-92%) and 43 (4.5%) had excessive erythrocytosis. Older age, decreased height-adjusted lung function, and higher body mass index (BMI) were associated with having an oxyhemoglobin saturation ≤85%. When adjusting for age, sex, socioeconomic status, having excessive erythrocytosis, and site, we found that each 5% decrease in oxyhemoglobin saturation was associated with a higher adjusted odds of metabolic syndrome (OR = 1.35, 95% CI: 1.07-1.72, p 2 mass units (OR = 1.29, 95% CI: 1.00-1.67, p < 0.05), hemoglobin A1c ≥6.5% (OR = 1.66, 95% CI: 1.09-2.51, p < 0.04), and high sensitivity C-reactive protein (hs-CRP) ≥3 mg/L (OR = 1.46, 95% CI: 1.09-1.96, p < 0.01). In high-altitude populations in Puno, Peru, a higher BMI and lower pulmonary function were

  18. Systems Design and Experimental Evaluation of a High-Altitude Relight Test Facility

    Science.gov (United States)

    Paxton, Brendan

    Novel advances in gas turbine engine combustor technology, led by endeavors into fuel efficiency and demanding environmental regulations, have been fraught with performance and safety concerns. While the majority of low emissions gas turbine engine combustor technology has been necessary for power generation applications, the push for ultra-low NOx combustion in aircraft jet engines has been ever present. Recent state-of-the-art combustor designs notably tackle historic emissions challenges by operating at fuel-lean conditions, which are characterized by an increase in the amount of air flow sent to the primary combustion zone. While beneficial in reducing NOx emissions, the fuel-lean mechanisms that characterize these combustor designs rely heavily upon high-energy and high-velocity air flows to sufficiently mix and atomize fuel droplets, ultimately leading to flame stability concerns during low-power operation. When operating at high-altitude conditions, these issues are further exacerbated by the presence of low ambient air pressures and temperatures, which can lead to engine flame-out situations and hamper engine relight attempts. To aid academic and industrial research ventures into improving the high-altitude lean blow-out and relight performance of modern gas turbine engine combustor technologies, the High-Altitude Relight Test Facility (HARTF) was designed and constructed at the University of Cincinnati (UC) Combustion and Fire Research Laboratory (CFRL). Following its construction, an experimental evaluation of its abilities to facilitate optically-accessible ignition, combustion, and spray testing for gas turbine engine combustor hardware at simulated high-altitude conditions was performed. In its evaluation, performance limit references were established through testing of the HARTF vacuum and cryogenic air-chilling capabilities. These tests were conducted with regard to end-user control---the creation and the maintenance of a realistic high-altitude

  19. Weather Avoidance Guidelines for NASA Global Hawk High-Altitude UAS

    Science.gov (United States)

    Cecil, Daniel J.; Zipser, Edward J.; Velden, Chris; Monette, Sarah; Heymsfield, Gerry; Braun, Scott; Newman, Paul; Black, Pete; Black, Michael; Dunion, Jason

    2014-01-01

    NASA operates two Global Hawk unmanned aircraft systems for Earth Science research projects. In particular, they are used in the Hurricane and Severe Storm Sentinel (HS3) project during 2012, 2013, and 2014 to take measurements from the environment around tropical cyclones, and from directly above tropical cyclones. There is concern that strict adherence to the weather avoidance rules used in 2012 may sacrifice the ability to observe important science targets. We have proposed modifications to these weather avoidance rules that we believe will improve the ability to observe science targets without compromising aircraft safety. The previous guidelines, used in 2012, specified: Do not approach thunderstorms within 25 nm during flight at FL500 or below. When flying above FL500: Do not approach reported lightning within 25NM in areas where cloud tops are reported at FL500 or higher. Aircraft should maintain at least 10000 ft vertical separation from reported lightning if cloud tops are below FL500. No over-flight of cumulus tops higher than FL500. No flight into forecast or reported icing conditions. No flight into forecast or reported moderate or severe turbulence Based on past experience with high-altitude flights over tropical cyclones, we have recommended changing this guidance to: Do not approach thunderstorms within 25 nm during flight at FL500 or below. Aircraft should maintain at least 5000 ft vertical separation from significant convective cloud tops except: a) When cloud tops above FL500: In the event of reported significant lightning activity or indicators of significant overshooting tops, do not approach within 10-25 nm, depending on pilot discretion and advice from Mission Scientist. b) When cloud tops are below FL500, maintain 10000 ft separation from reported significant lightning or indicators of significant overshooting tops. No flight into forecasted or reported icing conditions. No flight into forecasted or reported moderate or severe turbulence The

  20. ACUTE PHASE PROTEIN INCREASE IN HIGH ALTITUDE MOUNTAINEERS

    Directory of Open Access Journals (Sweden)

    Tolga Saka

    Full Text Available ABSTRACT Introduction: Many middle-aged Turks go hiking in mountains to breathe some fresh air or to maintain fitness. Objective: This study investigated the effects of regular high altitude mountain climbing on the metabolic and hematological responses of mountaineers. Methods: Hematological and biochemical parameters were studied, as well as some hormonal values of 21 mountaineers and 16 healthy age-matched sedentary volunteers. Results: The neutrophil to lymphocyte ratio (NLR was significantly lower (p<0.04 in mountaineers compared with the sedentary group. Total protein (p<0.001 and albumin (p<0.001 were lower, while the levels of ferritin (p<0.04, creatine (p<0.03 and creatine phosphokinase (p<0.01 were higher in mountaineers. Other hematological and biochemical parameters, i.e., erythrocytes, leukocytes, hemoglobin and hematocrit, did not change significantly. Conclusion: Our results show that regular exposure to high altitude increased the serum levels of some acute phase proteins with anti-inflammatory properties.

  1. United States high-altitude test experiences. A review emphasizing the impact on the environment

    International Nuclear Information System (INIS)

    Hoerlin, H.

    1976-06-01

    The US high-altitude nuclear explosions of the 1955-1962 period are listed chronologically; dates, locations, and yields are given. The major physical phases of the interactions of the weapon outputs with the atmosphere are described, such as the formation of fireballs at the low high-altitudes and the partition of energies and their distribution over very large spaces at the higher high-altitudes. The effects of these explosions on the normal activities of populations and the protective measures taken are documented. Many scientific observations, together with their significance and values, are reviewed. 109 refs

  2. Science 101: Why Does It Take Longer to Boil Potatoes at High Altitudes?

    Science.gov (United States)

    Robertson, Bill

    2017-01-01

    Why Does It Take Longer to Boil Potatoes at High Altitudes? This column provides background science information for elementary teachers. This month's issue looks at why water boils at different temperatures at different altitudes.

  3. Syndrome of Acute Anxiety Among Marines After Recent Arrival at High Altitude

    Science.gov (United States)

    2014-05-01

    Naval Health Research Center Syndrome of Acute Anxiety Among Marines After Recent Arrival at High Altitude Michael K. Sracic Darren Thomas...Allen Pate Jacob Norris Marc Norman, Jeffrey H. Gertsch Report No. 13-29 The views expressed in this article are those of the authors...MEDICINE, 179, 5:559, 2014 Syndrome of Acute Anxiety Among Marines After Recent Arrival at High Altitude LT Michael K. Sracic, MC USN*; LT Darren Thomas

  4. Improving Arctic Sea Ice Edge Forecasts by Assimilating High Horizontal Resolution Sea Ice Concentration Data into the US Navy’s Ice Forecast Systems

    Science.gov (United States)

    2016-06-13

    1735-2015 © Author(s) 2015. CC Attribution 3.0 License. Improving Arctic sea ice edge forecasts by assimilating high horizontal resolution sea ice...concentration data into the US Navy’s ice forecast systems P. G. Posey1, E. J. Metzger1, A. J. Wallcraft1, D. A. Hebert1, R. A. Allard1, O. M. Smedstad2...error within the US Navy’s operational sea ice forecast systems gained by assimilating high horizontal resolution satellite-derived ice concentration

  5. Recent Elevation Changes on Bagley Ice Valley, Guyot and Yahtse Glaciers, Alaska, from ICESat Altimetry, Star-3i Airborne, and SRTM Spaceborne DEMs

    Science.gov (United States)

    Muskett, R. R.; Sauber, J. M.; Lingle, C. S.; Rabus, B. T.; Tangborn, W. V.; Echelmeyer, K. A.

    2005-12-01

    Three- to 5-year surface elevation changes on Bagley Ice Valley, Guyot and Yahtse Glaciers, in the eastern Chugach and St. Elias Mtns of south-central Alaska, are estimated using ICESat-derived data and digital elevation models (DEMs) derived from interferometric synthetic aperture radar (InSAR) data. The surface elevations of these glaciers are influenced by climatic warming superimposed on surge dynamics (in the case of Bagley Ice Valley) and tidewater glacier dynamics (in the cases of Guyot and Yahtse Glaciers) in this coastal high-precipitation regime. Bagley Ice Valley / Bering Glacier last surged in 1993-95. Guyot and Yahtse Glaciers, as well as the nearby Tyndell Glacier, have experienced massive tidewater retreat during the past century, as well as during recent decades. The ICESat-derived elevation data we employ were acquired in early autumn in both 2003 and 2004. The NASA/NIMA Shuttle Radar Topography Mission (SRTM) DEM that we employ was derived from X-band InSAR data acquired during this 11-22 Feb. 2000 mission and processed by the German Aerospace Center. This DEM was corrected for estimated systematic error, and a mass balance model was employed to account for seasonal snow accumulation. The Star-3i airborne, X-band, InSAR-derived DEM that we employ was acquired 4-13 Sept. 2000 by Intermap Technologies, Inc., and was also processed by them. The ICESat-derived profiles crossing Bagley Ice Valley, differenced with Star-3i DEM elevations, indicate preliminary mean along-profile elevation increases of 5.6 ± 3.4 m at 1315 m altitude, 7.4 ± 2.7 m at 1448 m altitude, 4.7 ± 1.9 m at 1557 m altitude, 1.3 ± 1.4 m at 1774 m altitude, and 2.5 ± 1.5 m at 1781 m altitude. This is qualitatively consistent with the rising surface on Bagley Ice Valley observed by Muskett et al. [2003]. The ICESat-derived profiles crossing Yahtse Glacier, differenced with the SRTM DEM elevations, indicate preliminary mean elevation changes (negative implies decrease) of -0.9 ± 3

  6. Energy management strategy for solar-powered high-altitude long-endurance aircraft

    International Nuclear Information System (INIS)

    Gao, Xian-Zhong; Hou, Zhong-Xi; Guo, Zheng; Liu, Jian-Xia; Chen, Xiao-Qian

    2013-01-01

    Highlights: ► A new Energy Management Strategy (EMS) for high-altitude solar-powered aircraft is purposed. ► The simulations show that the aircraft can always keep the altitude above 16 km with the proposed EMS. ► The proposed EMS is capable to alleviate the power consumed for aircraft during night. ► The main technologies to improve the flight performance of aircraft are analyzed. - Abstract: Development of solar-powered High-Altitude Long-Endurance (HALE) aircraft has a great impact on both military and civil aviation industries since its features in high-altitude and energy source can be considered inexhaustible. Owing to the development constraints of rechargeable batteries, the solar-powered HALE aircraft must take amount of rechargeable batteries to fulfill the energy requirement in night, which greatly limits the operation altitude of aircraft. In order to solve this problem, a new Energy Management Strategy (EMS) is proposed based on the idea that the solar energy can be partly stored in gravitational potential in daytime. The flight path of HALE aircraft is divided into three stages. During the stage 1, the solar energy is stored in both lithium–sulfur battery and gravitational potential. The gravitational potential is released in stage 2 by gravitational gliding and the required power in stage 3 is supplied by lithium–sulfur battery. Correspondingly, the EMS is designed for each stage. The simulation results show that the aircraft can always keep the altitude above 16 km with the proposed EMS, and the power consumed during night can be also alleviated. Comparing with the current EMS, about 23.5% energy is remained in batteries with the proposed EMS during one day–night cycle. The sensitivities of the improvement of crucial technologies to the performance of aircraft are also analyzed. The results show that the enhancement of control and structural system, lithium–sulfur battery, and solar cell are ranked in descending order for the

  7. Peripheral blood lymphocytes: a model for monitoring physiological adaptation to high altitude.

    Science.gov (United States)

    Mariggiò, Maria A; Falone, Stefano; Morabito, Caterina; Guarnieri, Simone; Mirabilio, Alessandro; Pilla, Raffaele; Bucciarelli, Tonino; Verratti, Vittore; Amicarelli, Fernanda

    2010-01-01

    Depending on the absolute altitude and the duration of exposure, a high altitude environment induces various cellular effects that are strictly related to changes in oxidative balance. In this study, we used in vitro isolated peripheral blood lymphocytes as biosensors to test the effect of hypobaric hypoxia on seven climbers by measuring the functional activity of these cells. Our data revealed that a 21-day exposure to high altitude (5000 m) (1) increased intracellular Ca(2+) concentration, (2) caused a significant decrease in mitochondrial membrane potential, and (3) despite possible transient increases in intracellular levels of reactive oxygen species, did not significantly change the antioxidant and/or oxidative damage-related status in lymphocytes and serum, assessed by measuring Trolox-equivalent antioxidant capacity, glutathione peroxidase activity, vitamin levels, and oxidatively modified proteins and lipids. Overall, these results suggest that high altitude might cause an impairment in adaptive antioxidant responses. This, in turn, could increase the risk of oxidative-stress-induced cellular damage. In addition, this study corroborates the use of peripheral blood lymphocytes as an easily handled model for monitoring adaptive response to environmental challenge.

  8. The Laddermill : Innovative Wind Energy from High Altitudes in Holland and Australia

    NARCIS (Netherlands)

    Lansdorp, B.; Williams, P.

    2006-01-01

    The Laddermill is a novel concept to harvest electricity from high altitude winds. The concept's operating principle is to drive an electric generator using tethered kites. Several kites are deployed to altitudes of more than 1 km by means of a single cable that is connected to a drum on the

  9. The structure of high altitude O+ energization and outflow: a case study

    Directory of Open Access Journals (Sweden)

    H. Nilsson

    2004-07-01

    Full Text Available Multi-spacecraft observations from the CIS ion spectrometers on board the Cluster spacecraft have been used to study the structure of high-altitude oxygen ion energization and outflow. A case study taken from 12 April 2004 is discussed in more detail. In this case the spacecraft crossed the polar cap, mantle and high-altitude cusp region at altitudes between 4RE and 8RE and 2 of the spacecraft provided data. The oxygen ions were seen as a beam with narrow energy distribution, and increasing field-aligned velocity and temperature at higher altitude further in the upstream flow direction. The peak O+ energy was typically just above the highest energy of observed protons. The observed energies reached the upper limit of the CIS ion spectrometer, i.e. 38keV. Moment data from the spacecraft have been cross-correlated to determine cross-correlation coefficients, as well as the phase delay between the spacecraft. Structures in ion density, temperature and field-aligned flow appear to drift with the observed field-perpendicular drift. This, together with a velocity dispersion analysis, indicates that much of the structure can be explained by transverse heating well below the spacecraft. However, temperature isotropy and the particle flux as a function of field-aligned velocity are inconsistent with a single altitude Maxwellian source. Heating over extended altitude intervals, possibly all the way up to the observation point, seem consistent with the observations.

  10. Numerical research on the thermal performance of high altitude scientific balloons

    International Nuclear Information System (INIS)

    Dai, Qiumin; Xing, Daoming; Fang, Xiande; Zhao, Yingjie

    2017-01-01

    Highlights: • A model is presented to evaluate the IR radiation between translucent surfaces. • Comprehensive ascent and thermal models of balloons are established. • The effect of IR transmissivity on film temperature distribution is unneglectable. • Atmospheric IR radiation is the primary thermal factor of balloons at night. • Solar radiation is the primary thermal factor of balloons during the day. - Abstract: Internal infrared (IR) radiation is an important factor that affects the thermal performance of high altitude balloons. The internal IR radiation is commonly neglected or treated as the IR radiation between opaque gray bodies. In this paper, a mathematical model which considers the IR transmissivity of the film is proposed to estimate the internal IR radiation. Comprehensive ascent and thermal models for high altitude scientific balloons are established. Based on the models, thermal characteristics of a NASA super pressure balloon are simulated. The effects of film IR property on the thermal behaviors of the balloon are discussed in detail. The results are helpful for the design and operation of high altitude scientific balloons.

  11. Airframe Icing Research Gaps: NASA Perspective

    Science.gov (United States)

    Potapczuk, Mark

    2009-01-01

    qCurrent Airframe Icing Technology Gaps: Development of a full 3D ice accretion simulation model. Development of an improved simulation model for SLD conditions. CFD modeling of stall behavior for ice-contaminated wings/tails. Computational methods for simulation of stability and control parameters. Analysis of thermal ice protection system performance. Quantification of 3D ice shape geometric characteristics Development of accurate ground-based simulation of SLD conditions. Development of scaling methods for SLD conditions. Development of advanced diagnostic techniques for assessment of tunnel cloud conditions. Identification of critical ice shapes for aerodynamic performance degradation. Aerodynamic scaling issues associated with testing scale model ice shape geometries. Development of altitude scaling methods for thermal ice protections systems. Development of accurate parameter identification methods. Measurement of stability and control parameters for an ice-contaminated swept wing aircraft. Creation of control law modifications to prevent loss of control during icing encounters. 3D ice shape geometries. Collection efficiency data for ice shape geometries. SLD ice shape data, in-flight and ground-based, for simulation verification. Aerodynamic performance data for 3D geometries and various icing conditions. Stability and control parameter data for iced aircraft configurations. Thermal ice protection system data for simulation validation.

  12. Dose-response of altitude training: how much altitude is enough?

    Science.gov (United States)

    Levine, Benjamin D; Stray-Gundersen, James

    2006-01-01

    Altitude training continues to be a key adjunctive aid for the training of competitive athletes throughout the world. Over the past decade, evidence has accumulated from many groups of investigators that the "living high--training low" approach to altitude training provides the most robust and reliable performance enhancements. The success of this strategy depends on two key features: 1) living high enough, for enough hours per day, for a long enough period of time, to initiate and sustain an erythropoietic effect of high altitude; and 2) training low enough to allow maximal quality of high intensity workouts, requiring high rates of sustained oxidative flux. Because of the relatively limited access to environments where such a strategy can be practically applied, numerous devices have been developed to "bring the mountain to the athlete," which has raised the key issue of the appropriate "dose" of altitude required to stimulate an acclimatization response and performance enhancement. These include devices using molecular sieve technology to provide a normobaric hypoxic living or sleeping environment, approaches using very high altitudes (5,500m) for shorter periods of time during the day, and "intermittent hypoxic training" involving breathing very hypoxic gas mixtures for alternating 5 minutes periods over the course of 60-90 minutes. Unfortunately, objective testing of the strategies employing short term (less than 4 hours) normobaric or hypobaric hypoxia has failed to demonstrate an advantage of these techniques. Moreover individual variability of the response to even the best of living high--training low strategies has been great, and the mechanisms behind this variability remain obscure. Future research efforts will need to focus on defining the optimal dosing strategy for these devices, and determining the underlying mechanisms of the individual variability so as to enable the individualized "prescription" of altitude exposure to optimize the performance of

  13. No Change in Running Mechanics With Live High-Train Low Altitude Training in Elite Distance Runners.

    Science.gov (United States)

    Stickford, Abigail S L; Wilhite, Daniel P; Chapman, Robert F

    2017-01-01

    Investigations into ventilatory, metabolic, and hematological changes with altitude training have been completed; however, there is a lack of research exploring potential gait-kinematic changes after altitude training, despite a common complaint of athletes being a lack of leg "turnover" on return from altitude training. To determine if select kinematic variables changed in a group of elite distance runners after 4 wk of altitude training. Six elite male distance runners completed a 28-d altitude-training intervention in Flagstaff, AZ (2150 m), following a modified "live high-train low" model, wherein higherintensity runs were performed at lower altitudes (945-1150 m) and low-intensity sessions were completed at higher altitudes (1950-2850 m). Gait parameters were measured 2-9 d before departure to altitude and 1 to 2 d after returning to sea level at running speeds of 300-360 m/min. No differences were found in ground-contact time, swing time, or stride length or frequency after altitude training (P > .05). Running mechanics are not affected by chronic altitude training in elite distance runners. The data suggest that either chronic training at altitude truly has no effect on running mechanics or completing the live high-train low model of altitude training, where higher-velocity workouts are completed at lower elevations, mitigates any negative mechanical adaptations that may be associated with chronic training at slower speeds.

  14. Analysis of the Hybrid Power System for High-Altitude Unmanned Aircraft

    Directory of Open Access Journals (Sweden)

    Kangwen Sun

    2015-01-01

    Full Text Available The application of single solar array on high-altitude unmanned aircraft will waste energy because of its low conversion efficiency. Furthermore, since its energy utilization is limited, the surface temperature of solar array will rise to 70°C due to the waste solar energy, thus reducing the electrical performance of the solar array. In order to reuse the energy converted into heat by solar array, a hybrid power system is presented in this paper. In the hybrid power system, a new electricity-generating method is adopted to spread the photovoltaic cell on the wing surface and arrange photothermal power in the wing box section. Because the temperature on the back of photovoltaic cell is high, it can be used as the high-temperature heat source. The lower wing surface can be a low-temperature cold source. A high-altitude unmanned aircraft was used to analyze the performances of pure solar-powered aircraft and hybrid powered aircraft. The analysis result showed that the hybrid system could reduce the area of wing by 19% and that high-altitude unmanned aircraft with a 35 m or less wingspan could raise the utilization rate of solar energy per unit area after adopting the hybrid power system.

  15. Genomic analysis of natural selection and phenotypic variation in high-altitude mongolians.

    Directory of Open Access Journals (Sweden)

    Jinchuan Xing

    Full Text Available Deedu (DU Mongolians, who migrated from the Mongolian steppes to the Qinghai-Tibetan Plateau approximately 500 years ago, are challenged by environmental conditions similar to native Tibetan highlanders. Identification of adaptive genetic factors in this population could provide insight into coordinated physiological responses to this environment. Here we examine genomic and phenotypic variation in this unique population and present the first complete analysis of a Mongolian whole-genome sequence. High-density SNP array data demonstrate that DU Mongolians share genetic ancestry with other Mongolian as well as Tibetan populations, specifically in genomic regions related with adaptation to high altitude. Several selection candidate genes identified in DU Mongolians are shared with other Asian groups (e.g., EDAR, neighboring Tibetan populations (including high-altitude candidates EPAS1, PKLR, and CYP2E1, as well as genes previously hypothesized to be associated with metabolic adaptation (e.g., PPARG. Hemoglobin concentration, a trait associated with high-altitude adaptation in Tibetans, is at an intermediate level in DU Mongolians compared to Tibetans and Han Chinese at comparable altitude. Whole-genome sequence from a DU Mongolian (Tianjiao1 shows that about 2% of the genomic variants, including more than 300 protein-coding changes, are specific to this individual. Our analyses of DU Mongolians and the first Mongolian genome provide valuable insight into genetic adaptation to extreme environments.

  16. Prevalence of high altitude pulmonary hypertension among the natives of Spiti Valley--a high altitude region in Himachal Pradesh, India.

    Science.gov (United States)

    Negi, Prakash Chand; Marwaha, Rajeev; Asotra, Sanjeev; Kandoria, Arvind; Ganju, Neeraj; Sharma, Rajesh; Kumar, Ravi V; Bhardwaj, Rajeev

    2014-12-01

    The study aimed to determine the prevalence of high altitude pulmonary hypertension (HAPH) and its predisposing factors among natives of Spiti Valley. A cross-sectional survey study was done on the permanent natives of Spiti Valley residing at an altitude of 3000 m to 4200 m. Demographic characteristics, health behavior, anthropometrics, and blood pressure were recorded. Investigations included recording of 12 lead electrocardiogram (ECG), SaO2 with pulse oximeter, spirometry and echocardiography study, and measurement of Hb levels using the cynmethhemoglobin method. HAPH was diagnosed using criteria; tricuspid regurgitation (TR) gradient of ≥46 mmHg. ECG evidence of RV overload on 12 lead ECG was documented based on presence of 2 out of 3 criteria; R>S in V1, right axis deviation or RV strain, T wave inversion in V1 and V2. Data of 1087 subjects were analyzed who were free of cardiorespiratory diseases to determine the prevalence of HAPH and its predisposing factors. HAPH was recorded in 3.23% (95% C.I. of 0.9-8.1%) and ECG evidence of right ventricular (RV) overload was 1.5% in the study population. Prevalence of HAPH was not different in men and women 2.63% vs. 3.54% p<0.2. Age (Z statistics of 3.4 p<0.0006), hypoxemia (Z statistics of 2.9 p<0.002), and erythrocythemia (Z statistics of 4.7 p<0.003) were independently associated with HAPH. Altitude of residence was not found to be significantly associated with HAPH, although there was a trend of increasing prevalence with increasing altitude. It can be concluded that HAPH is prevalent in 3.23% of natives of Spiti Valley. Increasing age, erythrocythemia and hypoxemia are independent predisposing factors.

  17. THE STRUCTURE OF SURFACE H{sub 2}O LAYERS OF ICE-COVERED PLANETS WITH HIGH-PRESSURE ICE

    Energy Technology Data Exchange (ETDEWEB)

    Ueta, S.; Sasaki, T., E-mail: ueta@geo.titech.ac.jp, E-mail: takanori@geo.titech.ac.jp [Earth and Planetary Sciences, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551 (Japan)

    2013-10-01

    Many extrasolar (bound) terrestrial planets and free-floating (unbound) planets have been discovered. While the existence of bound and unbound terrestrial planets with liquid water is an important question, of particular importance is the question of these planets' habitability. Even for a globally ice-covered planet, geothermal heat from the planetary interior may melt the interior ice, creating an internal ocean covered by an ice shell. In this paper, we discuss the conditions that terrestrial planets must satisfy for such an internal ocean to exist on the timescale of planetary evolution. The question is addressed in terms of planetary mass, distance from a central star, water abundance, and abundance of radiogenic heat sources. In addition, we investigate the structure of the surface H{sub 2}O layers of ice-covered planets by considering the effects of ice under high pressure (high-pressure ice). As a fiducial case, a 1 M{sub ⊕} planet at 1 AU from its central star and with 0.6-25 times the H{sub 2}O mass of the Earth could have an internal ocean. We find that high-pressure ice layers may appear between the internal ocean and the rock portion on a planet with an H{sub 2}O mass over 25 times that of the Earth. The planetary mass and abundance of surface water strongly restrict the conditions under which an extrasolar terrestrial planet may have an internal ocean with no high-pressure ice under the ocean. Such high-pressure ice layers underlying the internal ocean are likely to affect the habitability of the planet.

  18. Tests of the Daimler D-IVa Engine at a High Altitude Test Bench

    Science.gov (United States)

    Noack, W G

    1920-01-01

    Reports of tests of a Daimler IVa engine at the test-bench at Friedrichshafen, show that the decrease of power of that engine, at high altitudes, was established, and that the manner of its working when air is supplied at a certain pressure was explained. These tests were preparatory to the installation of compressors in giant aircraft for the purpose of maintaining constant power at high altitudes.

  19. Observations and simulations of three-dimensional radiative interactions between Arctic boundary layer clouds and ice floes

    Science.gov (United States)

    Schäfer, M.; Bierwirth, E.; Ehrlich, A.; Jäkel, E.; Wendisch, M.

    2015-01-01

    Based on airborne spectral imaging observations three-dimensional (3-D) radiative effects between Arctic boundary layer clouds and ice floes have been identified and quantified. A method is presented to discriminate sea ice and open water in case of clouds from imaging radiance measurements. This separation simultaneously reveals that in case of clouds the transition of radiance between open water and sea ice is not instantaneously but horizontally smoothed. In general, clouds reduce the nadir radiance above bright surfaces in the vicinity of sea ice - open water boundaries, while the nadir radiance above dark surfaces is enhanced compared to situations with clouds located above horizontal homogeneous surfaces. With help of the observations and 3-D radiative transfer simulations, this effect was quantified to range between 0 and 2200 m distance to the sea ice edge. This affected distance Δ L was found to depend on both, cloud and sea ice properties. For a ground overlaying cloud in 0-200 m altitude, increasing the cloud optical thickness from τ = 1 to τ = 10 decreases Δ L from 600 to 250 m, while increasing cloud base altitude or cloud geometrical thickness can increase Δ L; Δ L(τ = 1/10) = 2200 m/1250 m for 500-1000 m cloud altitude. To quantify the effect for different shapes and sizes of the ice floes, various albedo fields (infinite straight ice edge, circles, squares, realistic ice floe field) were modelled. Simulations show that Δ L increases by the radius of the ice floe and for sizes larger than 6 km (500-1000 m cloud altitude) asymptotically reaches maximum values, which corresponds to an infinite straight ice edge. Furthermore, the impact of these 3-D-radiative effects on retrieval of cloud optical properties was investigated. The enhanced brightness of a dark pixel next to an ice edge results in uncertainties of up to 90 and 30% in retrievals of cloud optical thickness and effective radius reff, respectively. With help of Δ L quantified here, an

  20. Asthma in Patients Climbing to High and Extreme Altitudes in the Tibetan Everest Region

    NARCIS (Netherlands)

    Huismans, Henrike K.; Douma, W. Rob; Kerstjens, Huib A. M.; Renkema, Tineke E. J.

    Objectives: The aim of this study was to investigate the behavior of asthma in patients traveling to high and extreme altitudes. Methods: Twenty-four Dutch patients with mild asthma did a trekking at high and extreme altitudes (up to 6410 m = 21030 ft) in the Tibetan Everest region. Asthma symptoms,

  1. Ice Nucleation and Dehydration in the Tropical Tropopause Layer

    Science.gov (United States)

    Jensen, Eric J.; Diskin, Glenn S.; Lawson, R Paul; Lance, Sara; Bui, Thaopaul Van; Hlavka, Dennis L.; Mcgill, Matthew J.; Pfister, Leonhard; Toon, Owen B.; Gao, Rushan

    2013-01-01

    Optically thin cirrus near the tropical tropopause regulate the humidity of air entering the stratosphere, which in turn has a strong influence on the Earth's radiation budget and climate. Recent highaltitude, unmanned aircraft measurements provide evidence for two distinct classes of cirrus formed in the tropical tropopause region: (i) vertically extensive cirrus with low ice number concentrations, low extinctions, and large supersaturations (up to approx. 70%) with respect to ice; and (ii) vertically thin cirrus layers with much higher ice concentrations that effectively deplete the vapor in excess of saturation. The persistent supersaturation in the former class of cirrus is consistent with the long time-scales (several hours or longer) for quenching of vapor in excess of saturation given the low ice concentrations and cold tropical tropopause temperatures. The low-concentration clouds are likely formed on a background population of insoluble particles with concentrations less than 100 L-1 (often less than 20 L-1), whereas the high ice concentration layers (with concentrations up to 10,000 L-1) can only be produced by homogeneous freezing of an abundant population of aqueous aerosols. These measurements, along with past high-altitude aircraft measurements, indicate that the low-concentration cirrus occur frequently in the tropical tropopause region, whereas the high-concentration cirrus occur infrequently. The predominance of the low-concentration clouds means cirrus near the tropical tropopause may typically allow entry of air into the stratosphere with as much as approx. 1.7 times the ice saturation mixing ratio.

  2. Ground-State Structures of Ice at High-Pressures

    OpenAIRE

    McMahon, Jeffrey M.

    2011-01-01

    \\textit{Ab initio} random structure searching based on density functional theory is used to determine the ground-state structures of ice at high pressures. Including estimates of lattice zero-point energies, ice is found to adopt three novel crystal phases. The underlying sub-lattice of O atoms remains similar among them, and the transitions can be characterized by reorganizations of the hydrogen bonds. The symmetric hydrogen bonds of ice X and $Pbcm$ are initially lost as ice transforms to s...

  3. A method for sampling microbial aerosols using high altitude balloons.

    Science.gov (United States)

    Bryan, N C; Stewart, M; Granger, D; Guzik, T G; Christner, B C

    2014-12-01

    Owing to the challenges posed to microbial aerosol sampling at high altitudes, very little is known about the abundance, diversity, and extent of microbial taxa in the Earth-atmosphere system. To directly address this knowledge gap, we designed, constructed, and tested a system that passively samples aerosols during ascent through the atmosphere while tethered to a helium-filled latex sounding balloon. The sampling payload is ~ 2.7 kg and comprised of an electronics box and three sampling chambers (one serving as a procedural control). Each chamber is sealed with retractable doors that can be commanded to open and close at designated altitudes. The payload is deployed together with radio beacons that transmit GPS coordinates (latitude, longitude and altitude) in real time for tracking and recovery. A cut mechanism separates the payload string from the balloon at any desired altitude, returning all equipment safely to the ground on a parachute. When the chambers are opened, aerosol sampling is performed using the Rotorod® collection method (40 rods per chamber), with each rod passing through 0.035 m3 per km of altitude sampled. Based on quality control measurements, the collection of ~ 100 cells rod(-1) provided a 3-sigma confidence level of detection. The payload system described can be mated with any type of balloon platform and provides a tool for characterizing the vertical distribution of microorganisms in the troposphere and stratosphere. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Icebase: A suborbital survey to map geothermal heat flux under an ice sheet

    Science.gov (United States)

    Purucker, Michael E.; Connerney, John E. P.; Blakely, Richard J.; Bracken, Robert E.; Nowicki, Sophie; Le, Guan; Sabaka, Terence J.; Bonalsky, Todd M.; Kuang, Weijia; Ravat, Dhananjay; Ritz, Catherine; Vaughan, Alan P. M.; Gaina, Carmen; McEnroe, Suzanne; Lesur, Vincent

    2013-04-01

    resolution to approximately 250 km resolution. A high altitude, suborbital magnetic survey of Greenland would provide a heat flux model with resolution comparable to the crustal thickness, and would provide details of the high heat flux region associated with the Iceland mantle plume in E /SE Greenland, and the low heat flux region in NW Greenland, adjacent to the Canadian Shield. Magnetic field measurements from 20 km altitude are strongly preferred over lower altitude observations because of their ability to sample the longest wavelengths, provide uniform calibration with sufficient sensitivity, and suppress local remanent magnetic field signatures. We validate our heat flux estimates by assessing the possible contributions from remanent magnetism and variable susceptibility, and from other lithospheric processes such as structure, volcanism and impact, from unmodeled external magnetic fields, and from the assumptions utilized in the heat flux model.

  5. Signatures of electric fields from high and low altitude particle distributions

    International Nuclear Information System (INIS)

    Mizera, P.F.; Fennell, J.F.

    1977-01-01

    Measurements of high altitude (<1.3 R/sub e/) ions and electrons at auroral energies are used to provide evidence of parallel electric field acceleration over the dusk to midnight auroral regions for both the north and south hemispheres. The data, taken on August 12, 1976 by charged particle spectrometers on the S3-3 satellite, show evidence of potential differences of approx.2 kV below and approx.1 kV above a satellite altitude of 7300 km

  6. Detecting high spatial variability of ice shelf basal mass balance, Roi Baudouin Ice Shelf, Antarctica

    Directory of Open Access Journals (Sweden)

    S. Berger

    2017-11-01

    Full Text Available Ice shelves control the dynamic mass loss of ice sheets through buttressing and their integrity depends on the spatial variability of their basal mass balance (BMB, i.e. the difference between refreezing and melting. Here, we present an improved technique – based on satellite observations – to capture the small-scale variability in the BMB of ice shelves. As a case study, we apply the methodology to the Roi Baudouin Ice Shelf, Dronning Maud Land, East Antarctica, and derive its yearly averaged BMB at 10 m horizontal gridding. We use mass conservation in a Lagrangian framework based on high-resolution surface velocities, atmospheric-model surface mass balance and hydrostatic ice-thickness fields (derived from TanDEM-X surface elevation. Spatial derivatives are implemented using the total-variation differentiation, which preserves abrupt changes in flow velocities and their spatial gradients. Such changes may reflect a dynamic response to localized basal melting and should be included in the mass budget. Our BMB field exhibits much spatial detail and ranges from −14.7 to 8.6 m a−1 ice equivalent. Highest melt rates are found close to the grounding line where the pressure melting point is high, and the ice shelf slope is steep. The BMB field agrees well with on-site measurements from phase-sensitive radar, although independent radar profiling indicates unresolved spatial variations in firn density. We show that an elliptical surface depression (10 m deep and with an extent of 0.7 km × 1.3 km lowers by 0.5 to 1.4 m a−1, which we tentatively attribute to a transient adaptation to hydrostatic equilibrium. We find evidence for elevated melting beneath ice shelf channels (with melting being concentrated on the channel's flanks. However, farther downstream from the grounding line, the majority of ice shelf channels advect passively (i.e. no melting nor refreezing toward the ice shelf front. Although the absolute, satellite

  7. Certification and safety aspects relating to the transport of passengers on high altitude balloons in Europe

    Science.gov (United States)

    Schoenmaker, Annelie

    2014-07-01

    High-altitude balloons typically fly between 25 and 50 km in altitude, which, while below the Karman line of 100 km, is yet far above the altitudes typically flown by aircraft. For example, the highest-flying commercial aircraft - the Concorde - had a maximum cruising altitude of only 18 km. zero2infinity, a Spanish company, is currently developing a pressurized pod named “bloon” which will be capable of lifting six people, including two pilot crew members and four paying passengers, to an altitude of 36 km through the use of high-altitude balloons. The boundary between Airspace and Outer Space has never been legally defined, mostly because of the lack of activities taking place between the altitude where airplanes fly and the lowest orbiting spacecraft. High-altitude balloons do fly at these in-between altitudes and the prospect of commercializing access to these parts of the stratosphere poses some questions in a new light. Given the relatively low altitude at which they fly, it may well be that these types of balloons would be considered to operate exclusively within air space. However, given the technology involved in crewed high altitude balloon flights, which is more similar to spacecraft engineering than to traditional hot-air or gas ballooning, it is necessary to evaluate the various legal regimes, codes, and regulations that would apply to such flights, especially regarding licenses and liabilities. For high altitude balloon flights commencing in Europe, the European Aviation Safety Agency (EASA) would very likely be the competent certification or licensing agency for these flights, although there would likely be input from various national aviation authorities as well. However, because the European Commission (EC) has not yet issued regulations regarding commercial spaceflight, particularly the use of high altitude balloons, new rules and regulations governing such flights may still need to be drafted and promulgated. With the development of

  8. Late Holocene spatio-temporal variability of the south Greenland Ice Sheet and adjacent mountain glaciers

    Science.gov (United States)

    Sinclair, G.; Carlson, A. E.; Rood, D. H.; Axford, Y.

    2017-12-01

    The late Holocene, with its spatially complex pattern of centennial-scale climate variation, is an ideal time period to test the response of the cryosphere to atmospheric and oceanic temperature changes. The south Greenland Ice Sheet (sGrIS), with its proximity to areas of North Atlantic Deep Water formation and a large spectrum of glaciological regimes over a relatively small area, provides an excellent location to examine the spatial heterogeneity of ice-sheet and glacier responses to climate change. Here, we will present 50 Be-10 surface exposure ages from eight moraines in six locations around the margin of the sGrIS. These moraines are located just outboard of historical moraines, and will therefore allow us to constrain the timing of the most extensive prehistoric late-Holocene advance and retreat of ice margins draining the sGrIS and independent valley glaciers. The dataset includes both marine- and land-terminating glaciers draining the sGrIS, the low-altitude Qassimiut lobe, the high-altitude alpine Julianhåb ice cap and isolated valley glaciers. This diverse dataset will allow us to determine to what extent late-Holocene centennial-scale behavior of the ice-sheet and glacier margins were synchronous, perhaps in response to an external climate forcing, or more stochastic, governed instead by local factors such as basal thermal regime, bedrock topography, or microclimates. This has implications for understanding the forcings and responses of cryospheric changes at timescales relevant to human society. In addition to providing context for paleoclimatic and glacial geologic investigations, this work will inform future sea-level projections by providing targets for validating high-resolution ice-sheet and glacier models.

  9. Evaluation of the astrophysical origin of a vertical high-energy neutrino event in IceCube using IceTop information

    Energy Technology Data Exchange (ETDEWEB)

    Stahlberg, Martin; Auffenberg, Jan; Rongen, Martin; Kemp, Julian; Hansmann, Bengt; Schaufel, Merlin; Wiebusch, Christopher [RWTH Aachen, III. Physikalisches Institut B, Otto-Blumenthal-Strasse, 52074 Aachen (Germany); Collaboration: IceCube-Collaboration

    2015-07-01

    A main goal of the IceCube neutrino observatory is the detection of high-energy astrophysical neutrinos. IceCube's surface detector component IceTop is an array of 81 stations comprised of two Cherenkov-light detecting tanks, each of which is filled with clear ice and contains two photomultiplier modules. IceTop allows for the detection of cosmic-ray induced air-showers above energies of a few 100 TeV. In addition, the atmospheric origin of neutrino events detected with IceCube can be verified by the observation of a coincident air-shower component on the surface with IceTop. In 2014, a vertically down-going high-energy muon neutrino event starting in IceCube has been observed. The astrophysical origin of this event is tested by a close examination of the IceTop data. The outcome of this analysis is used to assess the potential of the proposed IceTop extension, IceVeto, which further increases the geometrical acceptance of the surface detector.

  10. S-40: Acute Phase Protein Increse in High Altitude Mountaineers

    Directory of Open Access Journals (Sweden)

    Tolga Saka

    2017-03-01

    Full Text Available “Erciyes Tigers” are an elite group of high altitude climbers. They have been climbing ErciyesMountain (3500 m, in Kayseri, Turkey once a week at least for ten years. When they climb Erciyes in winter, they also take a snow bath. This study investigated the effects of regular high altitude climbing on the metabolic and hematological responses of mountaineers. Venous blood samples were taken to investigate hematological, biochemical parameters and some hormone values from 21 mountaineers and 16 healthy age-matched sedentary volunteers at resting condition. The neutrophil/lymphocyte (N/L ratio was calculated. The N/L was associated with an increased risk of long-term mortality and it could provide a good measure of exercise stress and subsequent recovery. Most of the hematological and biochemical parameters i.e., erythrocyte, leukocyte, hemoglobin and hematocrit values did not change significantly. The neutrophil to lymphocyte (N/L ratio was significantly (p<0.04 decreased in the mountaineer compared with the sedentary group. Total protein (p<0.000 and albumin (0.001 were lower, while ferritin (p<0.04, creatine (p<0.03 and creatine phosphokinase levels (p<0.01 were higher in mountaineers. Our results show that regular high altitude climbing increased serum levels of some acute-phase proteins and these increments were not transient.

  11. Possibility of oil film detection on the ice cover of the sea surface

    International Nuclear Information System (INIS)

    Levin, I.M.; Radomyslskaya, T.M.; Osadchy, V.J.; Rybalka, N.N.; Klementieva, N.Y.; Zhou, J.; Li, Z.

    2009-01-01

    Ice cover in the Arctic regions makes the application of traditional remote methods of environmental monitoring difficult, and can also prevent the use of probes or other measurement tools. This paper presented a method of detecting oil pollution on ice-covered sea surfaces. The method was able to detect oil films on the lower ice-water boundary from above and below under both natural and artificial illumination. Pollution was detected when the sensor signal, the apparent contrast of oil-ice, and signal-noise ratio exceeded corresponding threshold values. A standard TV system at a low altitude was used to detect oil pollution on pure crystalline ice with a snow cover from 0.6 to 0.8 meters to several meters thick. At higher altitudes, the contrast in oil and water decreased due to the presence of atmospheric haze. Underwater pulsed-laser imaging systems were used to detect oil pollution when ice was covered by with soot, dust, aquatic plants, and phytoplankton pigments. It was concluded that both methods can be used to detect oil on the water-ice boundary. 10 refs., 1 tab., 5 figs

  12. Water level changes of high altitude lakes in Himalaya–Karakoram ...

    Indian Academy of Sciences (India)

    2Department of Geology, University of Pune, Pune 411 007, India. 3Chhattisgarh Council of .... influenced by three climate patterns as categorized by precipitation regime: (1) ... Water level changes of high altitude lakes in Himalaya–Karakoram. 1535 ...... mate warming and growth of high elevation inland lakes on the ...

  13. Defining the "dose" of altitude training: how high to live for optimal sea level performance enhancement.

    Science.gov (United States)

    Chapman, Robert F; Karlsen, Trine; Resaland, Geir K; Ge, R-L; Harber, Matthew P; Witkowski, Sarah; Stray-Gundersen, James; Levine, Benjamin D

    2014-03-15

    Chronic living at altitudes of ∼2,500 m causes consistent hematological acclimatization in most, but not all, groups of athletes; however, responses of erythropoietin (EPO) and red cell mass to a given altitude show substantial individual variability. We hypothesized that athletes living at higher altitudes would experience greater improvements in sea level performance, secondary to greater hematological acclimatization, compared with athletes living at lower altitudes. After 4 wk of group sea level training and testing, 48 collegiate distance runners (32 men, 16 women) were randomly assigned to one of four living altitudes (1,780, 2,085, 2,454, or 2,800 m). All athletes trained together daily at a common altitude from 1,250-3,000 m following a modified live high-train low model. Subjects completed hematological, metabolic, and performance measures at sea level, before and after altitude training; EPO was assessed at various time points while at altitude. On return from altitude, 3,000-m time trial performance was significantly improved in groups living at the middle two altitudes (2,085 and 2,454 m), but not in groups living at 1,780 and 2,800 m. EPO was significantly higher in all groups at 24 and 48 h, but returned to sea level baseline after 72 h in the 1,780-m group. Erythrocyte volume was significantly higher within all groups after return from altitude and was not different between groups. These data suggest that, when completing a 4-wk altitude camp following the live high-train low model, there is a target altitude between 2,000 and 2,500 m that produces an optimal acclimatization response for sea level performance.

  14. Food Abundance Is the Main Determinant of High-Altitude Range Use in Snub-Nosed Monkeys

    Directory of Open Access Journals (Sweden)

    Cyril C. Grueter

    2012-01-01

    Full Text Available High-altitude dwelling primates have to optimize navigating a space that contains both a vertical and horizontal component. Black-and-white or Yunnan snub-nosed monkeys (Rhinopithecus bieti are extreme by primate standards in inhabiting relatively cold subalpine temperate forests at very high altitudes where large seasonal variation in climate and food availability is expected to profoundly modulate their ranging strategies so as to ensure a positive energy balance. A “semi-nomadic” group of R. bieti was followed for 20 months in the montane Samage Forest, Baimaxueshan Nature Reserve, Yunnan, PRC, which consisted of evergreen conifers, oaks, and deciduous broadleaf trees. The aim of this study was to disentangle the effects of climate and phenology on patterns of altitudinal range use. Altitude used by the group ranged from a maximum of 3550 m in July 2007 to a minimum of 3060 m in April 2006. The proportional use of lichen, the monkeys’ staple fallback food, in the diet explained more variation in monthly use of altitudes than climatic factors and availability of flush and fruit. The abundance of lichens at high altitudes, the lack of alternative foods in winter, and the need to satisfy the monkey's basal energetic requirements explain the effect of lichenivory on use of altitudes.

  15. The lactate paradox revisited in lowlanders during acclimatization to 4100 m and in high-altitude natives

    DEFF Research Database (Denmark)

    Van Hall, Gerrit; Lundby, C; Araoz, M

    2009-01-01

    Chronic hypoxia has been proposed to induce a closer coupling in human skeletal muscle between ATP utilization and production in both lowlanders (LN) acclimatizing to high altitude and high-altitude natives (HAN), linked with an improved match between pyruvate availability and its use...... and remained at this higher level during the acclimatization period. HAN had similar high values; however, at the moment of exhaustion their muscle lactate, ADP and IMP content and Cr/PCr ratio were higher than in LN. In conclusion, sea-level residents in the course of acclimatization to high altitude did...... not exhibit a reduced capacity for the active muscle to produce lactate. Thus, the lactate paradox concept could not be demonstrated. High-altitude natives from the Andes actually exhibit a higher anaerobic energy production than lowlanders after 8 weeks of acclimatization reflected by an increased muscle...

  16. Statistics of high-altitude and high-latitude O+ ion outflows observed by Cluster/CIS

    Directory of Open Access Journals (Sweden)

    A. Korth

    2005-07-01

    Full Text Available The persistent outflows of O+ ions observed by the Cluster CIS/CODIF instrument were studied statistically in the high-altitude (from 3 up to 11 RE and high-latitude (from 70 to ~90 deg invariant latitude, ILAT polar region. The principal results are: (1 Outflowing O+ ions with more than 1keV are observed above 10 RE geocentric distance and above 85deg ILAT location; (2 at 6-8 RE geocentric distance, the latitudinal distribution of O+ ion outflow is consistent with velocity filter dispersion from a source equatorward and below the spacecraft (e.g. the cusp/cleft; (3 however, at 8-12 RE geocentric distance the distribution of O+ outflows cannot be explained by velocity filter only. The results suggest that additional energization or acceleration processes for outflowing O+ ions occur at high altitudes and high latitudes in the dayside polar region. Keywords. Magnetospheric physics (Magnetospheric configuration and dynamics, Solar wind-magnetosphere interactions

  17. Limnology and cyanobacterial diversity of high altitude lakes of ...

    Indian Academy of Sciences (India)

    Limnological data of four high altitude lakes from the cold desert region of Himachal Pradesh, India, has been correlated with cyanobacterial diversity. Physico-chemical characteristics and nutrient contents of the studied lakes revealed that Sissu Lake is mesotrophic while Chandra Tal, Suraj Tal and Deepak Tal are ...

  18. Inland and Near-Shore Water Profiles Derived from the High-Altitude Multiple Altimeter Beam Experimental Lidar (MABEL)

    Science.gov (United States)

    Jasinski, Michael F.; Stoll, Jeremy D.; Cook, William B.; Ondrusek, Michael; Stengel, Eric; Brunt, Kelly

    2016-01-01

    The Advanced Topographic Laser Altimeter System (ATLAS) on the Ice, Cloud, and Land Elevation Satellite (ICESat-2) mission is a six beam, low energy, high repetition rate, 532-nanometer laser transmitter with photon counting detectors. Although designed primarily for detecting height changes in ice caps, sea ice, and vegetation, the polar-orbiting satellite will observe global surface water during its designed three-year life span, including inland waterbodies, coasts, and open oceans. In preparation for the mission, an ICESat-2 prototype, the Multiple Altimeter Beam Experimental Lidar (MABEL), was built and flown on high-altitude aircraft experiments over a range of inland and near-shore targets. The purpose was to test the ATLAS concept and to provide a database for developing an algorithm that detects along track surface water height and light penetration under a range of atmospheric and water conditions. The current analysis examines the data sets of three MABEL transects observed from 20 kilometers above ground of coastal and inland waters conducted in 2012 and 2013. Transects ranged from about 2 to 12 kilometers in length and included the middle Chesapeake Bay, the near-shore Atlantic coast at Virginia Beach, and Lake Mead. Results indicate MABEL's high capability for retrieving surface water height statistics with a mean height precision ofapproximately 5-7 centimeters per 100-meter segment length. Profiles of attenuated subsurface backscatter, characterized using a Signal to Background Ratio written in Log10 base, or LSBR (sub 0), were observed over a range of 1.3 to 9.3 meters, depending on water clarity and atmospheric background. Results indicate that observable penetration depth, although primarily dependent on water properties, was greatest when the solar background rate was low. Near-shore bottom reflectance was detected only at the Lake Mead site down to a maximum of 10 meters under a clear night sky and low turbidity of approximately 1

  19. Water Ice Clouds and Dust in the Martian Atmosphere Observed by Mars Climate Sounder

    Science.gov (United States)

    Benson, Jennifer L.; Kass, David; Heavens, Nicholas; Kleinbohl, Armin

    2011-01-01

    The water ice clouds are primarily controlled by the temperature structure and form at the water condensation level. Clouds in all regions presented show day/night differences. Cloud altitude varies between night and day in the SPH and tropics: (1) NPH water ice opacity is greater at night than day at some seasons (2) The diurnal thermal tide controls the daily variability. (3) Strong day/night changes indicate that the amount of gas in the atmosphere varies significantly. See significant mixtures of dust and ice at the same altitude planet-wide (1) Points to a complex radiative and thermal balance between dust heating (in the visible) and ice heating or cooling in the infrared. Aerosol layering: (1) Early seasons reveal a zonally banded spatial distribution (2) Some localized longitudinal structure of aerosol layers (3) Later seasons show no consistent large scale organization

  20. Oxidative DNA damage and repair in skeletal muscle of humans exposed to high-altitude hypoxia

    DEFF Research Database (Denmark)

    Lundby, Carsten; Pilegaard, Henriette; van Hall, Gerrit

    2003-01-01

    Recent research suggests that high-altitude hypoxia may serve as a model for prolonged oxidative stress in healthy humans. In this study, we investigated the consequences of prolonged high-altitude hypoxia on the basal level of oxidative damage to nuclear DNA in muscle cells, a major oxygen-consuming...

  1. Novel drugs in the management of acute mountain sickness and high altitude pulmonary edema

    OpenAIRE

    Gaurav Sikri, Gaurav; Bhattacharya,Anirban

    2015-01-01

    Gaurav Sikri, Anirban Bhattacharya Department of Physiology, Armed Forces Medical College, Wanowarie, Pune, IndiaWe read with great interest the review article titled “Wilderness medicine at high altitude: recent developments in the field” by Shah et al.1 The authors have comprehensively summarized the recent advances in the field of high altitude medicine relevant to sports and travel medicine. However, Shah et al have described potential drugs for management of high-alti...

  2. Single particle measurements of the chemical composition of cirrus ice residue during CRYSTAL-FACE

    Science.gov (United States)

    Cziczo, D. J.; Murphy, D. M.; Hudson, P. K.; Thomson, D. S.

    2004-02-01

    The first real-time, in situ, investigation of the chemical composition of the residue of cirrus ice crystals was performed during July 2002. This study was undertaken on a NASA WB-57F high-altitude research aircraft as part of CRYSTAL-FACE, a field campaign which sought to further our understanding of the relation of clouds, water vapor, and climate by characterizing, among other parameters, anvil cirrus formed about the Florida peninsula. A counter flow virtual impactor (CVI) was used to separate cirrus ice from the unactivated interstitial aerosol particles and evaporate condensed-phase water. Residual material, on a crystal-by-crystal basis, was subsequently analyzed using the NOAA Aeronomy Laboratory's Particle Analysis by Laser Mass Spectrometry (PALMS) instrument. Sampling was performed from 5 to 15 km altitude and from 12° to 28° north latitude within cirrus originating over land and ocean. Chemical composition measurements provided several important results. Sea salt was often incorporated into cirrus, consistent with homogeneous ice formation by aerosol particles from the marine boundary layer. Size measurements showed that large particles preferentially froze over smaller ones. Meteoritic material was found within ice crystals, indicative of a relation between stratospheric aerosol particles and tropospheric clouds. Mineral dust was the dominant residue observed in clouds formed during a dust transport event from the Sahara, consistent with a heterogeneous freezing mechanism. These results show that chemical composition and size are important determinants of which aerosol particles form cirrus ice crystals.

  3. Sub-Scale Re-entry Capsule Drop via High Altitude Balloons

    Data.gov (United States)

    National Aeronautics and Space Administration — The project objective is to develop and test a sub-scale version of the Maraia Entry Capsule on a high altitude balloon. The capsule is released at 100,000 ft. The...

  4. High-altitude adaptation of Tibetan chicken from MT-COI and ATP-6 perspective.

    Science.gov (United States)

    Zhao, Xiaoling; Wu, Nan; Zhu, Qing; Gaur, Uma; Gu, Ting; Li, Diyan

    2016-09-01

    The problem of hypoxia adaptation in high altitudes is an unsolved brainteaser in the field of life sciences. As one of the best chicken breeds with adaptability to highland environment, the Tibetan chicken, is genetically different from lowland chicken breeds. In order to gain a better understanding of the mechanism of hypoxic adaptability in high altitude, in the present study, we focused on the MT-COI together with ATP-6 gene to explore the regulatory mechanisms for hypoxia adaptability in Tibet chicken. Here, we sequenced MT-COI of 29 Tibetan chickens and 30 Chinese domestic chickens and ATP-6 gene of 28 Tibetan chickens and 29 Chinese domestic chickens. In MT-COI gene, 9 single nucleotide polymorphisms (SNPs) were detected though none of these was a missense mutation, confirming the fact that MT-COI gene is a largely conservative sequence. In ATP-6 gene, 6 single nucleotide polymorphisms (SNPs) were detected and we found a missense mutation (m.9441G > A) in the ATP-6 gene of Tibetan chicken resulting in an amino acid substitution. Due to the critical role of ATP-6 gene in the proton translocation and energy metabolism, we speculated the possibility of this mutation playing an important role in easier energy conversion and metabolism in Tibetan chickens than Chinese domestic chickens so as to better adapt to the harsh environment of the high-altitude areas. The Median-joining profile also suggested that haplotype Ha2 has the ancestral position to the other haplotypes and has significant relationship with high-altitude adaptation in ATP-6 gene. Therefore, we considered that the polymorphism (m.9441G > A) in the ATP-6 gene may affect the specific functions of ATP-6 enzyme relating to high-altitude adaptation of Tibetan chicken and MT-COI gene is a largely conservative sequence.

  5. Flight Control of the High Altitude Wind Power System

    NARCIS (Netherlands)

    Podgaets, A.R.; Ockels, W.J.

    2007-01-01

    Closed loop Laddermill flight control problem is considered in this paper. Laddermill is a high altitude kites system for energy production. The kites have been simulated as rigid bodies and the cable as a thin elastic line. Euler angles and cable speed are controls. Flight control is written as a

  6. Predator-prey interaction reveals local effects of high-altitude insect migration

    Science.gov (United States)

    High-altitude nocturnal insect migrations represent significant pulses of resources, yet are difficult to study and poorly understood. Predator-prey interactions, specifically migratory moth consumption by high-flying bats, potentially reveal flows of migratory insects across a landscape. In North...

  7. Key issues of ultraviolet radiation of OH at high altitudes

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yuhuai; Wan, Tian; Jiang, Jianzheng; Fan, Jing [State Key Laboratory of High Temperature Gasdynamics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190 (China)

    2014-12-09

    Ultraviolet (UV) emissions radiated by hydroxyl (OH) is one of the fundamental elements in the prediction of radiation signature of high-altitude and high-speed vehicle. In this work, the OH A{sup 2}Σ{sup +}→X{sup 2}Π ultraviolet emission band behind the bow shock is computed under the experimental condition of the second bow-shock ultraviolet flight (BSUV-2). Four related key issues are discussed, namely, the source of hydrogen element in the high-altitude atmosphere, the formation mechanism of OH species, efficient computational algorithm of trace species in rarefied flows, and accurate calculation of OH emission spectra. Firstly, by analyzing the typical atmospheric model, the vertical distributions of the number densities of different species containing hydrogen element are given. According to the different dominating species containing hydrogen element, the atmosphere is divided into three zones, and the formation mechanism of OH species is analyzed in the different zones. The direct simulation Monte Carlo (DSMC) method and the Navier-Stokes equations are employed to compute the number densities of the different OH electronically and vibrationally excited states. Different to the previous work, the trace species separation (TSS) algorithm is applied twice in order to accurately calculate the densities of OH species and its excited states. Using a non-equilibrium radiation model, the OH ultraviolet emission spectra and intensity at different altitudes are computed, and good agreement is obtained with the flight measured data.

  8. High Altitude Remains Associated with Elevated Suicide Rates after Adjusting for Socioeconomic Status: A Study from South Korea

    OpenAIRE

    Kim, Jaelim; Choi, Nari; Lee, Yu-Jin; An, Hyonggin; Kim, Namkug; Yoon, Ho-Kyoung; Lee, Heon-Jeong

    2014-01-01

    There have been several studies supporting a possible relationship between high suicide rate and high altitude. However socioeconomic status may confound this association because low socioeconomic status, which is known to be related to a high suicide rate, is also associated with living at high altitude. This study aims to explore whether the relationship between high altitude and high suicide rate remains after adjusting for socioeconomic status in South Korea. We collected demographic data...

  9. Ben Macdhui High Altitude Trace Gas and Aerosol Transport Experiment

    CSIR Research Space (South Africa)

    Piketh, SJ

    1999-01-01

    Full Text Available The Ben Macdhui High Altitude Aerosol and Trace Gas Transport Experiment (BHATTEX) was started to characterize the nature and magnitude of atmospheric, aerosol and trace gas transport paths recirculation over and exiting from southern Africa...

  10. Modulation of ice ages via precession and dust-albedo feedbacks

    Directory of Open Access Journals (Sweden)

    Ralph Ellis

    2016-11-01

    Full Text Available We present here a simple and novel proposal for the modulation and rhythm of ice-ages and interglacials during the late Pleistocene. While the standard Milankovitch-precession theory fails to explain the long intervals between interglacials, these can be accounted for by a novel forcing and feedback system involving CO2, dust and albedo. During the glacial period, the high albedo of the northern ice sheets drives down global temperatures and CO2 concentrations, despite subsequent precessional forcing maxima. Over the following millennia more CO2 is sequestered in the oceans and atmospheric concentrations eventually reach a critical minima of about 200 ppm, which combined with arid conditions, causes a die-back of temperate and boreal forests and grasslands, especially at high altitude. The ensuing soil erosion generates dust storms, resulting in increased dust deposition and lower albedo on the northern ice sheets. As northern hemisphere insolation increases during the next Milankovitch cycle, the dust-laden ice-sheets absorb considerably more insolation and undergo rapid melting, which forces the climate into an interglacial period. The proposed mechanism is simple, robust, and comprehensive in its scope, and its key elements are well supported by empirical evidence.

  11. Evolved changes in the intracellular distribution and physiology of muscle mitochondria in high-altitude native deer mice.

    Science.gov (United States)

    Mahalingam, Sajeni; McClelland, Grant B; Scott, Graham R

    2017-07-15

    Mitochondrial function changes over time at high altitudes, but the potential benefits of these changes for hypoxia resistance remains unclear. We used high-altitude-adapted populations of deer mice, which exhibit enhanced aerobic performance in hypoxia, to examine whether changes in mitochondrial physiology or intracellular distribution in the muscle contribute to hypoxia resistance. Permeabilized muscle fibres from the gastrocnemius muscle had higher respiratory capacities in high-altitude mice than in low-altitude mice. Highlanders also had higher mitochondrial volume densities, due entirely to an enriched abundance of subsarcolemmal mitochondria, such that more mitochondria were situated near the cell membrane and adjacent to capillaries. There were several effects of hypoxia acclimation on mitochondrial function, some of which were population specific, but they differed from the evolved changes in high-altitude natives, which probably provide a better indication of adaptive traits that improve performance and hypoxia resistance at high altitudes. High-altitude natives that have evolved to live in hypoxic environments provide a compelling system to understand how animals can overcome impairments in oxygen availability. We examined whether these include changes in mitochondrial physiology or intracellular distribution that contribute to hypoxia resistance in high-altitude deer mice (Peromyscus maniculatus). Mice from populations native to high and low altitudes were born and raised in captivity, and as adults were acclimated to normoxia or hypobaric hypoxia (equivalent to 4300 m elevation). We found that highlanders had higher respiratory capacities in the gastrocnemius (but not soleus) muscle than lowlanders (assessed using permeabilized fibres with single or multiple inputs to the electron transport system), due in large part to higher mitochondrial volume densities in the gastrocnemius. The latter was attributed to an increased abundance of subsarcolemmal

  12. Stratospheric and solar cycle effects on long-term variability of mesospheric ice clouds

    Science.gov (United States)

    Lübken, F.-J.; Berger, U.; Baumgarten, G.

    2009-11-01

    Model results of mesospheric ice layers and background conditions at 69°N from 1961 to 2008 are analyzed. The model nudges to European Centre for Medium-Range Weather Forecasts data below ˜45 km. Greenhouse gas concentrations in the mesosphere are kept constant. At polar mesospheric cloud (PMC) altitudes (83 km) temperatures decrease until the mid 1990s by -0.08 K/yr resulting in trends of PMC brightness, occurrence rates, and, to a lesser extent, in PMC altitudes (-0.0166 km/yr). Ice layer trends are consistent with observations by ground-based and satellite instruments. Water vapor increases at PMC heights and decreases above due to increased freeze-drying caused by the temperature trend. Temperature trends in the mesosphere mainly come from shrinking of the stratosphere and from dynamical effects. A solar cycle modulation of H2O is observed in the model consistent with satellite observations. The effect on ice layers is reduced because of redistribution of H2O by freeze-drying. The accidental coincidence of low temperatures and solar cycle minimum in the mid 1990s leads to an overestimation of solar effects on ice layers. A strong correlation between temperatures and PMC altitudes is observed. Applied to historical measurements this gives negligible temperature trends at PMC altitudes (˜0.01-0.02 K/yr). Strong correlations between PMC parameters and background conditions deduced from the model confirm the standard scenario of PMC formation. The PMC sensitivity on temperatures, water vapor, and Ly-α is investigated. PMC heights show little variation with background parameters whereas brightness and occurrence rates show large variations. None of the background parameters can be ignored regarding its influence on ice layers.

  13. NEURO ENGINEERING TECHNOLOGY TO ACCELERATE THE HUMAN ADAPTATION TO HIGH ALTITUDE HYPOXIA

    Directory of Open Access Journals (Sweden)

    Mukhamed T. Shaov

    2018-01-01

    Full Text Available Abstract. The aim is to study the influence of neuro-information signals modulated by pulse hypoxia on the rhythm of cardiac contractions in low-mountain and high-mountain conditions. Methods. Heart rate was measured using the pulse oxymetry device ELOX-01M2. The impact analysis of information-wave signals was carried out with the help of the neuro-protector "Anthropotherapist", non-invasively (remotely at a distance of up to 5 meters for 5 min. /day during 10 days. The investigations were carried out in lowmountain conditions (city of Nalchik, 550 m above sea level and highlands, Mount Elbrus (site of "Garabashi", 3780 m. above sea level. Participants in the study were divided into groups: control group – 18 participants; experimental group - 18 participants. In the low-mountain and high-mountain conditions, the control group was not affected by the neuro-protector. In high-mountain conditions, the participants in the control group experienced only the effects of high-altitude hypoxia sessions. The experimental group was exposed to the neuro-information signals from the neuro-protector. High-altitude studies were carried out in the following mode: heart rate was recorded at the altitudes of Nalchik - exit to Elbrus – on the way to the site of "Garabashi" - return route to Nalchik. Results. It was found that with frequency exposure, there is a significant decrease and fluctuations in heart rate in low-mountain inhabitants. The stability of these changes in the rhythm of cardiac activity can also be seen in conditions of high-altitude hypoxia. Conclusion. Consequently, the proposed mode of frequency impact, implemented using the "Anthropotherapist" neuro-protector technology, can form a stage of adaptation to hypoxia and unfavorable climatic and environmental factors.

  14. Phenylethanoid glycosides of Pedicularis muscicola Maxim ameliorate high altitude-induced memory impairment.

    Science.gov (United States)

    Zhou, Baozhu; Li, Maoxing; Cao, Xinyuan; Zhang, Quanlong; Liu, Yantong; Ma, Qiang; Qiu, Yan; Luan, Fei; Wang, Xianmin

    2016-04-01

    Exposure to hypobaric hypoxia causes oxidative stress, neuronal degeneration and apoptosis that leads to memory impairment. Though oxidative stress contributes to neuronal degeneration and apoptosis in hypobaric hypoxia, the ability for phenylethanoid glycosides of Pedicularis muscicola Maxim (PhGs) to reverse high altitude memory impairment has not been studied. Rats were supplemented with PhGs orally for a week. After the fourth day of drug administration, rats were exposed to a 7500 m altitude simulation in a specially designed animal decompression chamber for 3 days. Spatial memory was assessed by the 8-arm radial maze test before and after exposure to hypobaric hypoxia. Histological assessment of neuronal degeneration was performed by hematoxylin-eosin (HE) staining. Changes in oxidative stress markers and changes in the expression of the apoptotic marker, caspase-3, were assessed in the hippocampus. Our results demonstrated that after exposure to hypobaric hypoxia, PhGs ameliorated high altitude memory impairment, as shown by the decreased values obtained for reference memory error (RME), working memory error (WME), and total error (TE). Meanwhile, administration of PhGs decreased hippocampal reactive oxygen species levels and consequent lipid peroxidation by elevating reduced glutathione levels and enhancing the free radical scavenging enzyme system. There was also a decrease in the number of pyknotic neurons and a reduction in caspase-3 expression in the hippocampus. These findings suggest that PhGs may be used therapeutically to ameliorate high altitude memory impairment. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. The implementation of sea ice model on a regional high-resolution scale

    Science.gov (United States)

    Prasad, Siva; Zakharov, Igor; Bobby, Pradeep; McGuire, Peter

    2015-09-01

    The availability of high-resolution atmospheric/ocean forecast models, satellite data and access to high-performance computing clusters have provided capability to build high-resolution models for regional ice condition simulation. The paper describes the implementation of the Los Alamos sea ice model (CICE) on a regional scale at high resolution. The advantage of the model is its ability to include oceanographic parameters (e.g., currents) to provide accurate results. The sea ice simulation was performed over Baffin Bay and the Labrador Sea to retrieve important parameters such as ice concentration, thickness, ridging, and drift. Two different forcing models, one with low resolution and another with a high resolution, were used for the estimation of sensitivity of model results. Sea ice behavior over 7 years was simulated to analyze ice formation, melting, and conditions in the region. Validation was based on comparing model results with remote sensing data. The simulated ice concentration correlated well with Advanced Microwave Scanning Radiometer for EOS (AMSR-E) and Ocean and Sea Ice Satellite Application Facility (OSI-SAF) data. Visual comparison of ice thickness trends estimated from the Soil Moisture and Ocean Salinity satellite (SMOS) agreed with the simulation for year 2010-2011.

  16. Comparative study of acetazolamide and spironolactone on body fluid compartments on induction to high altitude

    Science.gov (United States)

    Singh, M. V.; Jain, S. C.; Rawal, S. B.; Divekar, H. M.; Parshad, Rajinder; Tyagi, A. K.; Sinha, K. C.

    1986-03-01

    Studies were conducted on 29 male healthy subjects having no previous experience of living at high altitude. These subjects were divided into three groups, i.e., subjects treated with placebo, acetazolamide and spironolactone. These subjects were first studied in Delhi. The drug schedule was started 24 hour prior to the airlift of these subjects to an altitude of 3,500 m and was continued for 48 hour after arrival at high altitude. Total body water, extra cellular water, plasma volume, blood electrolytes, pH, pO2, pCO2 and blood viscosity were determined on 3rd and 12th day of their stay at high altitude. Total body water, extra cellular water intracellular water and plasma volume decreased on high altitude exposure. There was a further slight decrease in these compartments with acetazolamide and spironolactone. It was also observed that spironolactone drives out more water from the extracellular compartment. Loss of plasma water was also confirmed by increased plasma osmolality. Increase in arterial blood pH was noticed on hypoxic exposure but the increase was found less in acetazolamide and spironolactone cases. This decrease in pH is expected to result in better oxygen delivery to the tissues at the low oxygen tension. It was also confirmed because blood pO2 increased in both the groups. No significant change in plasma electrolytes was observed in subjects of various groups. Blood viscosity slightly increased on exposure to high altitude. The degree of rise was found less in the group treated with spironolactone. This study suggests that both the drugs are likely to be beneficial in ameliorating/prevention of AMS syndrome.

  17. Multichannel surface clutter suppression: East Antarctica P-band SAR ice sounding in the presence of grating lobes

    DEFF Research Database (Denmark)

    Bekaert, David; Gebert, Nicolas; Lin, Chung-Chi

    2014-01-01

    with the European Space Agency's P-band POLarimetric Airborne Radar Ice Sounder (POLARIS). The 4 m long antenna of POLARIS enables simultaneous reception of up to four across-track channels. It was operated in 2011 over Antarctica at a high flight altitude of 3200 m. Different coherent weighting techniques...

  18. Rhodiola crenulata- and Cordyceps sinensis-based supplement boosts aerobic exercise performance after short-term high altitude training.

    Science.gov (United States)

    Chen, Chung-Yu; Hou, Chien-Wen; Bernard, Jeffrey R; Chen, Chiu-Chou; Hung, Ta-Cheng; Cheng, Lu-Ling; Liao, Yi-Hung; Kuo, Chia-Hua

    2014-09-01

    High altitude training is a widely used strategy for improving aerobic exercise performance. Both Rhodiola crenulata (R) and Cordyceps sinensis (C) supplements have been reported to improve exercise performance. However, it is not clear whether the provision of R and C during high altitude training could further enhance aerobic endurance capacity. In this study, we examined the effect of R and C based supplementation on aerobic exercise capacity following 2-week high altitude training. Alterations to autonomic nervous system activity, circulatory hormonal, and hematological profiles were investigated. Eighteen male subjects were divided into two groups: Placebo (n=9) and R/C supplementation (RC, n=9). Both groups received either RC (R: 1400 mg+C: 600 mg per day) or the placebo during a 2-week training period at an altitude of 2200 m. After 2 weeks of altitude training, compared with Placebo group, the exhaustive run time was markedly longer (Placebo: +2.2% vs. RC: +5.7%; paltitude training (paltitude training provides greater training benefits in improving aerobic performance. This beneficial effect of RC treatment may result from better maintenance of PNS activity and accelerated physiological adaptations during high altitude training.

  19. A Model to Assess the Risk of Ice Accretion Due to Ice Crystal Ingestion in a Turbofan Engine and its Effects on Performance

    Science.gov (United States)

    Jorgenson, Philip C. E.; Veres, Joseph P.; Wright, William B.; Struk, Peter M.

    2013-01-01

    The occurrence of ice accretion within commercial high bypass aircraft turbine engines has been reported under certain atmospheric conditions. Engine anomalies have taken place at high altitudes that were attributed to ice crystal ingestion, partially melting, and ice accretion on the compression system components. The result was one or more of the following anomalies: degraded engine performance, engine roll back, compressor surge and stall, and flameout of the combustor. The main focus of this research is the development of a computational tool that can estimate whether there is a risk of ice accretion by tracking key parameters through the compression system blade rows at all engine operating points within the flight trajectory. The tool has an engine system thermodynamic cycle code, coupled with a compressor flow analysis code, and an ice particle melt code that has the capability of determining the rate of sublimation, melting, and evaporation through the compressor blade rows. Assumptions are made to predict the complex physics involved in engine icing. Specifically, the code does not directly estimate ice accretion and does not have models for particle breakup or erosion. Two key parameters have been suggested as conditions that must be met at the same location for ice accretion to occur: the local wet-bulb temperature to be near freezing or below and the local melt ratio must be above 10%. These parameters were deduced from analyzing laboratory icing test data and are the criteria used to predict the possibility of ice accretion within an engine including the specific blade row where it could occur. Once the possibility of accretion is determined from these parameters, the degree of blockage due to ice accretion on the local stator vane can be estimated from an empirical model of ice growth rate and time spent at that operating point in the flight trajectory. The computational tool can be used to assess specific turbine engines to their susceptibility to

  20. Circulation, metabolism, and ventilation during prolonged exposure to carbon monoxide and to high altitude

    Energy Technology Data Exchange (ETDEWEB)

    Klausen, K.; Rasmussen, B; Gjellerod, H.; Madsen, H.; Petersen, E.

    1968-01-01

    Eight volunteers were exposed to CO (13% COHb) or high altitude (3454 m). There was no change in circulation, metabolism, or ventilation during CO exposure. With similar arterial O/sub 2/ concentration from high-altitude, V/sub e/ (BTPS) increased, Pa/sub CO/sub 2// decreased. Regulating mechanisms respond to a decrease in Pa/sub CO/sub 2// rather than a gereral lack in tissue O/sub 2/ per se.

  1. Increase of cerebral blood flow at high altitude

    DEFF Research Database (Denmark)

    Lassen, N A

    1992-01-01

    but rather somewhat sharpened over five days at almost 4000 meters of altitude. This, along with other evidence, shows that CBF does not in itself adapt to chronic hypoxia. Nevertheless, a decrease in CBF is seen over days at constant altitude primarily due to increase in the hematocrit. The cerebral...

  2. Prediction of future hydrological regimes in poorly gauged high altitude basins: the case study of the upper Indus, Pakistan

    Directory of Open Access Journals (Sweden)

    D. Bocchiola

    2011-07-01

    Full Text Available In the mountain regions of the Hindu Kush, Karakoram and Himalaya (HKH the "third polar ice cap" of our planet, glaciers play the role of "water towers" by providing significant amount of melt water, especially in the dry season, essential for agriculture, drinking purposes, and hydropower production. Recently, most glaciers in the HKH have been retreating and losing mass, mainly due to significant regional warming, thus calling for assessment of future water resources availability for populations down slope. However, hydrology of these high altitude catchments is poorly studied and little understood. Most such catchments are poorly gauged, thus posing major issues in flow prediction therein, and representing in fact typical grounds of application of PUB concepts, where simple and portable hydrological modeling based upon scarce data amount is necessary for water budget estimation, and prediction under climate change conditions. In this preliminarily study, future (2060 hydrological flows in a particular watershed (Shigar river at Shigar, ca. 7000 km2, nested within the upper Indus basin and fed by seasonal melt from major glaciers, are investigated.

    The study is carried out under the umbrella of the SHARE-Paprika project, aiming at evaluating the impact of climate change upon hydrology of the upper Indus river. We set up a minimal hydrological model, tuned against a short series of observed ground climatic data from a number of stations in the area, in situ measured ice ablation data, and remotely sensed snow cover data. The future, locally adjusted, precipitation and temperature fields for the reference decade 2050–2059 from CCSM3 model, available within the IPCC's panel, are then fed to the hydrological model. We adopt four different glaciers' cover scenarios, to test sensitivity to decreased glacierized areas. The projected flow duration curves, and some selected flow descriptors are evaluated. The uncertainty of

  3. Kinetic boundaries and phase transformations of ice i at high pressure

    Science.gov (United States)

    Wang, Yu; Zhang, Huichao; Yang, Xue; Jiang, Shuqing; Goncharov, Alexander F.

    2018-01-01

    Raman spectroscopy in diamond anvil cells has been employed to study phase boundaries and transformation kinetics of H2O ice at high pressures up to 16 GPa and temperatures down to 15 K. Ice i formed at nearly isobaric cooling of liquid water transforms on compression to high-density amorphous (HDA) ice at 1.1-3 GPa at 15-100 K and then crystallizes in ice vii with the frozen-in disorder (ice vii') which remains stable up to 14.1 GPa at 80 K and 15.9 GPa at 100 K. Unexpectedly, on decompression of ice vii', it transforms to ice viii in its domain of metastability, and then it relaxes into low-density amorphous (LDA) ice on a subsequent pressure release and warming up. On compression of ice i at 150-170 K, ice ix is crystallized and no HDA ice is found; further compression of ice ix results in the sequential phase transitions to stable ices vi and viii. Cooling ice i to 210 K at 0.3 GPa transforms it to a stable ice ii. Our extensive investigations provide previously missing information on the phase diagram of water, especially on the kinetic paths that result in formation of phases which otherwise are not accessible; these results are keys for understanding the phase relations including the formation of metastable phases. Our observations inform on the ice modifications that can occur naturally in planetary environments and are not accessible for direct observations.

  4. Usefulness of training camps at high altitude for well-trained adolescents

    Directory of Open Access Journals (Sweden)

    Jiří Suchý

    2015-03-01

    Full Text Available Objective: Opinions on the suitability of sports training at altitudes of 1800-2200 m above sea level (ASL for increasing performance in youth are not unanimous. The objective of this study was to test the influence of a ten day altitude training camp on performance in well-trained adolescent cross-country skiers. Methods: A running test of 3 × 2 km (aerobic, anaerobic and critical intensity was used with a rest interval of 10 minutes. The test was performed 4 times - an initial test at a lowland (900 m ASL prior to departure for altitude, two tests at altitude (1850 m ASL, a final test ten days after returning to lower altitudes. The aerobic, anaerobic and critical load intensities were set by graded a load test. For all individual tests, the participants maintained the same heart rate individually defined for the various segments using a heart rate monitor. Changes in speed between the tests were compared. The body's internal response was also monitored by the concentration of lactate (2 and 8 minutes after each exertion. Participants: Well-trained adolescent cross-country skiers (N = 11, age: 14.4 ± 1.2 years, weight: 54.4 ± 8.6 kg, height: 170 ± 7 cm, fat: 13 ± 2.6%. Results: The average times attained in the first altitude test for aerobic and anaerobic load were higher (p < .05 than in the entry test at low altitude. In the second altitude test the average times for all intensities were significantly (p < .05 higher than in the first altitude test. In the tests after returning to the lower altitudes the times attained for all intensities were on average higher than at altitude. The average lactate concentration levels following the various intensities were similar (p > .05. The dynamics of the cool-down monitored via the lactate value at the eighth minute after completing the relevant segment showed that at altitude the adolescents cooled down significantly (p < .05 slower rate following the aerobic and anaerobic intensity than at

  5. The STAR Data Reporting Guidelines for Clinical High Altitude Research.

    Science.gov (United States)

    Brodmann Maeder, Monika; Brugger, Hermann; Pun, Matiram; Strapazzon, Giacomo; Dal Cappello, Tomas; Maggiorini, Marco; Hackett, Peter; Bärtsch, Peter; Swenson, Erik R; Zafren, Ken

    2018-03-01

    Brodmann Maeder, Monika, Hermann Brugger, Matiram Pun, Giacomo Strapazzon, Tomas Dal Cappello, Marco Maggiorini, Peter Hackett, Peter Baärtsch, Erik R. Swenson, Ken Zafren (STAR Core Group), and the STAR Delphi Expert Group. The STARdata reporting guidelines for clinical high altitude research. High AltMedBiol. 19:7-14, 2018. The goal of the STAR (STrengthening Altitude Research) initiative was to produce a uniform set of key elements for research and reporting in clinical high-altitude (HA) medicine. The STAR initiative was inspired by research on treatment of cardiac arrest, in which the establishment of the Utstein Style, a uniform data reporting protocol, substantially contributed to improving data reporting and subsequently the quality of scientific evidence. The STAR core group used the Delphi method, in which a group of experts reaches a consensus over multiple rounds using a formal method. We selected experts in the field of clinical HA medicine based on their scientific credentials and identified an initial set of parameters for evaluation by the experts. Of 51 experts in HA research who were identified initially, 21 experts completed both rounds. The experts identified 42 key parameters in 5 categories (setting, individual factors, acute mountain sickness and HA cerebral edema, HA pulmonary edema, and treatment) that were considered essential for research and reporting in clinical HA research. An additional 47 supplemental parameters were identified that should be reported depending on the nature of the research. The STAR initiative, using the Delphi method, identified a set of key parameters essential for research and reporting in clinical HA medicine.

  6. The extreme melt across the Greenland ice sheet in 2012

    Science.gov (United States)

    Nghiem, S. V.; Hall, D. K.; Mote, T. L.; Tedesco, M.; Albert, M. R.; Keegan, K.; Shuman, C. A.; DiGirolamo, N. E.; Neumann, G.

    2012-10-01

    The discovery of the 2012 extreme melt event across almost the entire surface of the Greenland ice sheet is presented. Data from three different satellite sensors - including the Oceansat-2 scatterometer, the Moderate-resolution Imaging Spectroradiometer, and the Special Sensor Microwave Imager/Sounder - are combined to obtain composite melt maps, representing the most complete melt conditions detectable across the ice sheet. Satellite observations reveal that melt occurred at or near the surface of the Greenland ice sheet across 98.6% of its entire extent on 12 July 2012, including the usually cold polar areas at high altitudes like Summit in the dry snow facies of the ice sheet. This melt event coincided with an anomalous ridge of warm air that became stagnant over Greenland. As seen in melt occurrences from multiple ice core records at Summit reported in the published literature, such a melt event is rare with the last significant one occurring in 1889 and the next previous one around seven centuries earlier in the Medieval Warm Period. Given its rarity, the 2012 extreme melt across Greenland provides an exceptional opportunity for new studies in broad interdisciplinary geophysical research.

  7. The role of oxygen-increased respirator in humans ascending to high altitude

    Directory of Open Access Journals (Sweden)

    Shen Guanghao

    2012-08-01

    Full Text Available Abstract Background Acute mountain sickness (AMS is common for people who live in low altitude areas ascending to the high altitude. Many instruments have been developed to treat mild cases of AMS. However, long-lasting and portable anti-hypoxia equipment for individual is not yet available. Methods Oxygen-increased respirator (OIR has been designed to reduce the risk of acute mountain sickness in acute exposure to low air pressure. It can increase the density of oxygen by increasing total atmospheric pressure in a mask. Male subjects were screened, and eighty-eight were qualified to perform the experiments. The subjects were divided into 5 groups and were involved in some of the tests at 4 different altitudes (Group 1, 2: 3700 m; Group 3,4,5: 4000 m, 4700 m, 5380 m with and without OIR. These tests include heart rate, saturation of peripheral oxygen (SpO2, malondialdehyde (MDA, superoxide dismutase (SOD, blood lactate (BLA and PWC (physical work capacity -170. Results The results showed that higher SpO2, lower heart rate (except during exercise and better recovery of heart rate were observed from all the subjects ’with OIR’ compared with ’without OIR’ (P Conclusions We suggested that OIR may play a useful role in protecting people ascending to high altitude before acclimatization.

  8. Pathophysiology of acute mountain sickness and high altitude pulmonary oedema

    DEFF Research Database (Denmark)

    Sutton, J R; Lassen, N

    1979-01-01

    We review the evidence that acute mountain sickness (AMS) and high altitude pulmonary oedema (HAPO) occur together more often than is realized. We hypothesize that AMS and HAPO have a common pathophysiological basis: both are due to increased pressure and flow in the microcirculation, causing...

  9. The paradox of extreme high-altitude migration in bar-headed geese Anser indicus

    Science.gov (United States)

    Hawkes, L. A.; Balachandran, S.; Batbayar, N.; Butler, P. J.; Chua, B.; Douglas, D. C.; Frappell, P. B.; Hou, Y.; Milsom, W. K.; Newman, S. H.; Prosser, D. J.; Sathiyaselvam, P.; Scott, G. R.; Takekawa, J. Y.; Natsagdorj, T.; Wikelski, M.; Witt, M. J.; Yan, B.; Bishop, C. M.

    2013-01-01

    Bar-headed geese are renowned for migratory flights at extremely high altitudes over the world's tallest mountains, the Himalayas, where partial pressure of oxygen is dramatically reduced while flight costs, in terms of rate of oxygen consumption, are greatly increased. Such a mismatch is paradoxical, and it is not clear why geese might fly higher than is absolutely necessary. In addition, direct empirical measurements of high-altitude flight are lacking. We test whether migrating bar-headed geese actually minimize flight altitude and make use of favourable winds to reduce flight costs. By tracking 91 geese, we show that these birds typically travel through the valleys of the Himalayas and not over the summits. We report maximum flight altitudes of 7290 m and 6540 m for southbound and northbound geese, respectively, but with 95 per cent of locations received from less than 5489 m. Geese travelled along a route that was 112 km longer than the great circle (shortest distance) route, with transit ground speeds suggesting that they rarely profited from tailwinds. Bar-headed geese from these eastern populations generally travel only as high as the terrain beneath them dictates and rarely in profitable winds. Nevertheless, their migration represents an enormous challenge in conditions where humans and other mammals are only able to operate at levels well below their sea-level maxima. PMID:23118436

  10. Increased Cardiometabolic Risk and Worsening Hypoxemia at High Altitude

    OpenAIRE

    Miele, Catherine H.; Schwartz, Alan R.; Gilman, Robert H.; Pham, Luu; Wise, Robert A.; Davila-Roman, Victor G.; Jun, Jonathan C.; Polotsky, Vsevolod Y.; Miranda, J. Jaime; Leon-Velarde, Fabiola; Checkley, William

    2016-01-01

    Miele, Catherine H., Alan R. Schwartz, Robert H. Gilman, Luu Pham, Robert A. Wise, Victor G. Davila-Roman, Jonathan C. Jun, Vsevolod Y. Polotsky, J. Jaime Miranda, Fabiola Leon-Velarde, and William Checkley. Increased cardiometabolic risk and worsening hypoxemia at high altitude. High Alt Med Biol. 17:93���100, 2016.���Metabolic syndrome, insulin resistance, diabetes, and dyslipidemia are associated with an increased risk of cardiovascular disease. While excessive erythrocytosis is associated...

  11. Perseus A High Altitude Remotely Piloted Aircraft being Towed in Flight

    Science.gov (United States)

    1994-01-01

    Perseus A, a remotely piloted, high-altitude research vehicle designed by Aurora Flight Sciences Corp., takes off from Rogers Dry Lake at the Dryden Flight Research Center, Edwards, California. The Perseus was towed into the air by a ground vehicle. At about 700 ft. the aircraft was released and the engine turned the propeller to take the plane to its desired altitude. Perseus B is a remotely piloted aircraft developed as a design-performance testbed under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project. Perseus is one of several flight vehicles involved in the ERAST project. A piston engine, propeller-powered aircraft, Perseus was designed and built by Aurora Flight Sciences Corporation, Manassas, Virginia. The objectives of Perseus B's ERAST flight tests have been to reach and maintain horizontal flight above altitudes of 60,000 feet and demonstrate the capability to fly missions lasting from 8 to 24 hours, depending on payload and altitude requirements. The Perseus B aircraft established an unofficial altitude record for a single-engine, propeller-driven, remotely piloted aircraft on June 27, 1998. It reached an altitude of 60,280 feet. In 1999, several modifications were made to the Perseus aircraft including engine, avionics, and flight-control-system improvements. These improvements were evaluated in a series of operational readiness and test missions at the Dryden Flight Research Center, Edwards, California. Perseus is a high-wing monoplane with a conventional tail design. Its narrow, straight, high-aspect-ratio wing is mounted atop the fuselage. The aircraft is pusher-designed with the propeller mounted in the rear. This design allows for interchangeable scientific-instrument payloads to be placed in the forward fuselage. The design also allows for unobstructed airflow to the sensors and other devices mounted in the payload compartment. The Perseus B that underwent test and development in 1999 was the third generation of the

  12. Causes and effects of long periods of ice cover on a remote high Alpine lake

    Directory of Open Access Journals (Sweden)

    Michael STURM

    2000-09-01

    Full Text Available The response of the physical and chemical limnology of Hagelseewli (2339 m a.s.l. to local meteorological forcing was investigated from 1996 to 1998 using an automatic weather station, thermistor chains, water samples and sediment traps. On-site meteorological measurements revealed the paramount importance of local topographic shading for the limnology of the lake. A high cliff to the south diminishes incident radiation by 15% to 90%, resulting in a long period of ice cover. Hence, the spring and summer seasons are extremely condensed, allowing only about 2 months per year for mixing, oxygen uptake, nutrient inflow, water exchange and phytoplankton growth. Regular measurements of water temperature, chemistry and diatom composition show that Hagelseewli responds very rapidly to changes in nutrient concentrations and light conditions. This response is restricted mainly to an extremely short productivity pulse, which takes place as soon as the lake is completely free of ice. Ice-free conditions are indicated by the occurrence of planktonic diatoms. In contrast to most low-altitude lakes, maximum productivity occurs in the middle of the water column (6-9 m, where first light, and then soluble reactive phosphorus (SRP, are the limiting factors. During the period of thawing, large amounts of ammonium enter the lake. Nevertheless, allochthonous nutrient input is not important because SRP, the limiting nutrient for algal growth, originates from the sediments. Water chemistry data and data from sediment traps show that, although autochthonous calcite precipitation does occur, the calcite crystals are redissolved completely in the bottom waters during the extended period of ice cover. Thus, the most important factor for changes in the nutrient budget, primary production and preservation of calcite is the bottom water oxygen status, which is governed by the occurrence of an ice-free period. We hypothesise that the duration of the ice-free period is of

  13. Integrated Modelling of an Unmanned High-Altitude Solar-Powered Aircraft for Control Law Design Analysis

    OpenAIRE

    Klöckner, Andreas; Leitner, Martin; Schlabe, Daniel; Looye, Gertjan

    2013-01-01

    Solar-powered high-altitude unmanned platforms are highly optimized and integrated aircraft. In order to account for the complex, multi-physical interactions between their systems, we propose using integrated simulation models throughout the aircraft’s life cycle. Especially small teams with limited ressources should benefit from this approach. In this paper, we describe our approach to an integrated model of the Electric High-Altitude Solar-Powered Aircraft ELHASPA. It includes aspects of th...

  14. Isothermal pumping analysis for high-altitude tethered balloons.

    Science.gov (United States)

    Kuo, Kirsty A; Hunt, Hugh E M

    2015-06-01

    High-altitude tethered balloons have potential applications in communications, surveillance, meteorological observations and climate engineering. To maintain balloon buoyancy, power fuel cells and perturb atmospheric conditions, fluids could be pumped from ground level to altitude using the tether as a hose. This paper examines the pumping requirements of such a delivery system. Cases considered include delivery of hydrogen, sulfur dioxide (SO2) and powders as fluid-based slurries. Isothermal analysis is used to determine the variation of pressures and velocities along the pipe length. Results show that transport of small quantities of hydrogen to power fuel cells and maintain balloon buoyancy can be achieved at pressures and temperatures that are tolerable in terms of both the pipe strength and the current state of pumping technologies. To avoid solidification, transport of SO2 would require elevated temperatures that cannot be tolerated by the strength fibres in the pipe. While the use of particle-based slurries rather than SO2 for climate engineering can reduce the pipe size significantly, the pumping pressures are close to the maximum bursting pressure of the pipe.

  15. Human nutrition in cold and high terrestrial altitudes

    Science.gov (United States)

    Srivastava, K. K.; Kumar, Ratan

    1992-03-01

    The calorie and nutritional requirements for a man working in an alien hostile environment of cold regions and high altitude are described and compared to those of normal requirements. Carbohydrates, fats and vitamins fulfilling the caloric and nutritional requirements are generally available in adequate amounts except under conditions of appetite loss. However, the proteins and amino acids should be provided in such a way as to meet the altered behavioral and metabolic requirements. Work in extreme cold requires fulfilling enhanced calorie needs. In high mountainous regions, cold combined with hypoxia produced loss of appetite and necessitated designing of special foods.

  16. Short-term adaptation and chronic cardiac remodelling to high altitude in lowlander natives and Himalayan Sherpa.

    Science.gov (United States)

    Stembridge, Mike; Ainslie, Philip N; Shave, Rob

    2015-11-01

    What is the topic of this review? At high altitude, the cardiovascular system must adapt in order to meet the metabolic demand for oxygen. This review summarizes recent findings relating to short-term and life-long cardiac adaptation to high altitude in the context of exercise capacity. What advances does it highlight? Both Sherpa and lowlanders exhibit smaller left ventricular volumes at high altitude; however, myocardial relaxation, as evidenced by diastolic untwist, is reduced only in Sherpa, indicating that short-term hypoxia does not impair diastolic relaxation. Potential remodelling of systolic function, as evidenced by lower left ventricular systolic twist in Sherpa, may facilitate the requisite sea-level mechanical reserve required during exercise, although this remains to be confirmed. Both short-term and life-long high-altitude exposure challenge the cardiovascular system to meet the metabolic demand for O2 in a hypoxic environment. As the demand for O2 delivery increases during exercise, the circulatory component of oxygen transport is placed under additional stress. Acute adaptation and chronic remodelling of cardiac structure and function may occur to facilitate O2 delivery in lowlanders during sojourn to high altitude and in permanent highland residents. However, our understanding of cardiac structural and functional adaption in Sherpa remains confined to a higher maximal heart rate, lower pulmonary vascular resistance and no differences in resting cardiac output. Ventricular form and function are intrinsically linked through the left ventricular (LV) mechanics that facilitate efficient ejection, minimize myofibre stress during contraction and aid diastolic recoil. Recent examination of LV mechanics has allowed detailed insight into fundamental cardiac adaptation in high-altitude Sherpa. In this symposium report, we review recent advances in our understanding of LV function in both lowlanders and Sherpa at rest and discuss the potential consequences

  17. On the observation of unusual high concentration of small chain-like aggregate ice crystals and large ice water contents near the top of a deep convective cloud during the CIRCLE-2 experiment

    Directory of Open Access Journals (Sweden)

    J.-F. Gayet

    2012-01-01

    IWC up to 1 g m−3 may be observed near the cloud top. Extrapolating the relationship for stronger convective clouds with similar ice particles, IWC up to 5 g m−3 could be experienced with reflectivity factors no larger than about 20 dBZ. This means that for similar situations, indication of rather weak radar echo does not necessarily warn the occurrence of high ice water content carried by small ice crystals. All along the cloud penetration the shape of the ice crystals is dominated by chain-like aggregates of frozen droplets. Our results confirm previous observations that the chains of ice crystals are found in a continental deep convective systems which are known generally to generate intense electric fields causing efficient ice particle aggregation processes. Vigorous updrafts could lift supercooled droplets which are frozen extremely rapidly by homogeneous nucleation near the −37 °C level, producing therefore high concentrations of very small ice particles at upper altitudes. They are sufficient to deplete the water vapour and suppress further nucleation as confirmed by humidity measurements. These observations address scientific issues related to the microphysical properties and structure of deep convective clouds and confirm that particles smaller than 50 μm may control the radiative properties in convective-related clouds. These unusual observations may also provide some possible insights regarding engineering issues related to the failure of jet engines commonly used on commercial aircraft during flights through areas of high ice water content. However, large uncertainties of the measured and derived parameters limit our observations.

  18. On the observation of unusual high concentration of small chain-like aggregate ice crystals and large ice water contents near the top of a deep convective cloud during the CIRCLE-2 experiment

    Science.gov (United States)

    Gayet, J.-F.; Mioche, G.; Bugliaro, L.; Protat, A.; Minikin, A.; Wirth, M.; Dörnbrack, A.; Shcherbakov, V.; Mayer, B.; Garnier, A.; Gourbeyre, C.

    2012-01-01

    . Extrapolating the relationship for stronger convective clouds with similar ice particles, IWC up to 5 g m-3 could be experienced with reflectivity factors no larger than about 20 dBZ. This means that for similar situations, indication of rather weak radar echo does not necessarily warn the occurrence of high ice water content carried by small ice crystals. All along the cloud penetration the shape of the ice crystals is dominated by chain-like aggregates of frozen droplets. Our results confirm previous observations that the chains of ice crystals are found in a continental deep convective systems which are known generally to generate intense electric fields causing efficient ice particle aggregation processes. Vigorous updrafts could lift supercooled droplets which are frozen extremely rapidly by homogeneous nucleation near the -37 °C level, producing therefore high concentrations of very small ice particles at upper altitudes. They are sufficient to deplete the water vapour and suppress further nucleation as confirmed by humidity measurements. These observations address scientific issues related to the microphysical properties and structure of deep convective clouds and confirm that particles smaller than 50 μm may control the radiative properties in convective-related clouds. These unusual observations may also provide some possible insights regarding engineering issues related to the failure of jet engines commonly used on commercial aircraft during flights through areas of high ice water content. However, large uncertainties of the measured and derived parameters limit our observations.

  19. Solar cycle and long term variations of mesospheric ice layers

    Science.gov (United States)

    Lübken, Franz-Josef; Berger, Uwe; Kiliani, Johannes; Baumgarten, Gerd; Fiedler, Jens; Gerding, Michael

    2010-05-01

    Ice layers in the summer mesosphere at middle and polar latitudes, frequently called `noctilucent clouds' (NLC) or `polar mesosphere clouds'(PMC), are considered to be sensitive indicators of long term changes in the middle atmosphere. We present a summary of long term observations from the ground and from satellites and compare with results from the LIMA model (Leibniz Institute Middle Atmosphere Model). LIMA nicely reproduces mean conditions of the summer mesopause region and also mean characteristics of ice layers. LIMA nudges to ECMWF data in the troposphere and lower stratosphere which influences the background conditions in the mesosphere and thereby the morphology of ice clouds. A strong correlation between temperatures and PMC altitudes is observed. Applied to historical measurements this give s negligible temperature trends at PMC altitudes (approximately 0.01-0.02 K/y). Trace gas concentrations are kept constant in LIMA except for water vapor which is modified by variable solar radiation. Still, long term trends in temperatures and ice layer parameters are observed, consistent with observations. As will be shown, these trends originate in the stratosphere. Solar cycle effects are expected in ice layers due to variations in background temperatures and water paper. We will present results from LIMA regarding solar cycle variations and compare with NLC observations at our lidar stations in Kühlungsborn (54°N) and ALOMAR (69°N), and also with satellite measurements.

  20. Aero-thermo-dynamic analysis of the Spaceliner-7.1 vehicle in high altitude flight

    Science.gov (United States)

    Zuppardi, Gennaro; Morsa, Luigi; Sippel, Martin; Schwanekamp, Tobias

    2014-12-01

    SpaceLiner, designed by DLR, is a visionary, extremely fast passenger transportation concept. It consists of two stages: a winged booster, a vehicle. After separation of the two stages, the booster makes a controlled re-entry and returns to the launch site. According to the current project, version 7-1 of SpaceLiner (SpaceLiner-7.1), the vehicle should be brought at an altitude of 75 km and then released, undertaking the descent path. In the perspective that the vehicle of SpaceLiner-7.1 could be brought to altitudes higher than 75 km, e.g. 100 km or above and also for a speculative purpose, in this paper the aerodynamic parameters of the SpaceLiner-7.1 vehicle are calculated in the whole transition regime, from continuum low density to free molecular flows. Computer simulations have been carried out by three codes: two DSMC codes, DS3V in the altitude interval 100-250 km for the evaluation of the global aerodynamic coefficients and DS2V at the altitude of 60 km for the evaluation of the heat flux and pressure distributions along the vehicle nose, and the DLR HOTSOSE code for the evaluation of the global aerodynamic coefficients in continuum, hypersonic flow at the altitude of 44.6 km. The effectiveness of the flaps with deflection angle of -35 deg. was evaluated in the above mentioned altitude interval. The vehicle showed longitudinal stability in the whole altitude interval even with no flap. The global bridging formulae verified to be proper for the evaluation of the aerodynamic coefficients in the altitude interval 80-100 km where the computations cannot be fulfilled either by CFD, because of the failure of the classical equations computing the transport coefficients, or by DSMC because of the requirement of very high computer resources both in terms of the core storage (a high number of simulated molecules is needed) and to the very long processing time.

  1. How might the North American ice sheet influence the northwestern Eurasian climate?

    Science.gov (United States)

    Beghin, P.; Charbit, S.; Dumas, C.; Kageyama, M.; Ritz, C.

    2015-10-01

    altitude of the American ice sheet leads to less total precipitation and snowfall and to colder temperatures over both the Scandinavian and the Barents and Kara sea sectors. We then compute the resulting annual surface mass balance over the Fennoscandian region from the simulated temperature and precipitation fields used to force an ice-sheet model. It clearly appears that the SMB is dominated by the ablation signal. In response to the summer cooling induced by the American ice-sheet albedo, high positive SMB values are obtained over the Eurasian region, leading thus to the growth of an ice sheet. On the contrary, the gradual increase of the American ice-sheet altitude induces more ablation over the Eurasian sector, hence limiting the growth of Fennoscandia. To test the robustness of our results with respect to the Eurasian ice sheet state, we carried out two additional LMDZ experiments with new boundary conditions involving both the American (flat or full LGM) and high Eurasian ice sheets. The most striking result is that the Eurasian ice sheet is maintained under full-LGM North American ice-sheet conditions, but loses ~ 10 % of its mass compared to the case in which the North American ice sheet is flat. These new findings qualitatively confirm the conclusions from our first series of experiments and suggest that the development of the Eurasian ice sheet may have been slowed down by the growth of the American ice sheet, offering thereby a new understanding of the evolution of Northern Hemisphere ice sheets throughout glacial-interglacial cycles.

  2. Global dose to man from proposed NNTRP high altitude nuclear tests

    International Nuclear Information System (INIS)

    Peterson, K.R.

    1975-05-01

    Radionuclide measurements from past high altitude nuclear testing have enabled development of a model to estimate surface deposition and doses from 400 kt of fission products injected in winter within the Pacific Test Area at altitudes in excess of 50 km. The largest 30-year average dose to man is about 10 millirem and occurs at 30 0 to 50 0 N latitude. The principal contributor to this dose is external gamma radiation from gross fission products. Individual doses from 90 Sr via the forage-cow-milk pathway and 137 Cs via the pasture-meat pathway are about 1/5 the gross fission product doses. The global 30-year population dose is 3 x 10 7 person-rem, which compares with a 30-year natural background population dose of 1 X 10 10 person-rem. Due in large part to the global distribution of population, over 98 percent of the global person-rem from the proposed high altitude tests is received in the Northern Hemisphere, while about 75 percent of the total population dose occurs within the 30 0 --50 0 N latitude belt. Detonations in summer would decrease the global dose by about a factor of three. (U.S.)

  3. [Arterial hypertension due to altitude].

    Science.gov (United States)

    Domej, Wolfgang; Trapp, Michael; Miggitsch, Eva Maria; Krakher, Tiziana; Riedlbauer, Rita; Roher, Peter; Schwaberger, Günther

    2008-01-01

    The behavior of blood pressure under hypoxic conditions depends on individual factors, altitude and duration of stay at altitude. While most humans are normotensive at higher altitudes, a few will react with moderate hypertension or hypotension. Excessive elevation of arterial blood pressure is not even to be expected below 4,000 m. Rather, several weeks' stay at higher altitude will decrease systolic and diastolic blood pressure at rest as well as during physical exertion. A high-altitude treatment for rehabilitation purposes at moderate altitude may be recommended for patients with cardio-circulatory disorders. Improvements can last several months even after returning to accustomed altitudes. Furthermore, endurance-trained hypertensive patients with pharmacologically controlled arterial blood pressure might be able to participate in mountain treks without additional health risk.

  4. Formation of ice XII at low temperatures and high pressures

    International Nuclear Information System (INIS)

    Schober, H.; Koza, M.; Toelle, A.; Fujara, F.

    1999-01-01

    Complete text of publication follows. Solid water features a large variety of crystalline as well as two amorphous phases. The versatility of water's behavior has been reinforced recently by the identification of still another form of crystalline ice [1]. Ice XII was obtained by cooling liquid water to 260 K at a pressure of 5.5 kbar. Ice XII could be produced in a completely different region of water's phase diagram [2]. Using a. piston-cylinder apparatus ice XII was formed during the production of high-density amorphous ice (HDA) at 77 K as described previously [3]. The amount of crystalline ice XII contamination within the HDA sample varies in a so far unpredictable way with both extremes, i.e. pure HDA as well as pure ice XII. realized. Our results indicate that water's phase diagram needs modification in the region assigned to HDA. Ice XII is characterized as well as its transition towards cubic ice by elastic and inelastic neutron scattering. (author)

  5. Parasympathetic neural activity accounts for the lowering of exercise heart rate at high altitude

    DEFF Research Database (Denmark)

    Boushel, Robert Christopher; Calbet, J A; Rådegran, G

    2001-01-01

    In chronic hypoxia, both heart rate (HR) and cardiac output (Q) are reduced during exercise. The role of parasympathetic neural activity in lowering HR is unresolved, and its influence on Q and oxygen transport at high altitude has never been studied.......In chronic hypoxia, both heart rate (HR) and cardiac output (Q) are reduced during exercise. The role of parasympathetic neural activity in lowering HR is unresolved, and its influence on Q and oxygen transport at high altitude has never been studied....

  6. Molecular mechanisms regulating oxygen transport and consumption in high altitude and hibernating mammals

    DEFF Research Database (Denmark)

    Revsbech, Inge Grønvall

    2016-01-01

    The aim of this thesis is to broaden the knowledge of molecular mechanisms of adjustment in oxygen (O2) uptake, conduction, delivery and consumption in mammals adapted to extreme conditions. For this end, I have worked with animals living at high altitude as an example of environmental hypoxia...... of the repeatedly found adaptive traits in animals living at high altitude and in hibernating mammals during hibernation compared with the active state. Factors that affect O2 affinity of Hb include temperature, H+/CO2 via the Bohr effect as well as Cl- and organic phosphates, in mammals mainly 2...

  7. Rationale and operational plan for a U.S. high-altitude magnetic survey

    Science.gov (United States)

    Hildenbrand, Thomas G.; Acuna, Mario; Bracken, Robert E.; Hardwick, Doug; Hinze, William J.; Keller, Gordon R.; Phillips, Jeff; Roest, Walter

    2002-01-01

    On August 8, 2002, twenty-one scientists from the federal, private and academic sectors met at a workshop in Denver, Co., to discuss the feasibility of collecting magnetic anomaly data on a Canberra aircraft (Figure 1). The need for this 1-day workshop arose because of an exciting and cost-effective opportunity to collect invaluable magnetic anomaly data during a Canberra mission over the U.S. in 2003 and 2004. High Altitude Mapping Missions (HAMM) is currently planning a mission to collect Interferometric Synthetic Aperture Radar (IFSAR) imagery at an altitude of about 15 km and with a flight-line spacing of about 18 km over the conterminous U.S. and Alaska. The additional collection of total and vector magnetic field data would represent a secondary mission objective (i.e., a "piggy-back" magnetometer system). Because HAMM would fund the main flight costs of the mission, the geomagnetic community would obtain invaluable magnetic data at a nominal cost. These unique data would provide new insights on fundamental tectonic and thermal processes and give a new view of the structural and lithologic framework of the crust and possibly the upper mantle. This document highlights: (1) the reasons to conduct this national survey and (2) a preliminary operational plan to collect high-altitude magnetic data of a desired quality and for the expected resources. Although some operational plan issues remain to be resolved, the important conclusions of the workshop are that the Canberra is a very suitable platform to measure the magnetic field and that the planned mission will result in quality high-altitude magnetic data to greatly expand the utility of our national magnetic database.

  8. Short-term cardiorespiratory adaptation to high altitude in children compared with adults.

    Science.gov (United States)

    Kriemler, S; Radtke, T; Bürgi, F; Lambrecht, J; Zehnder, M; Brunner-La Rocca, H P

    2016-02-01

    As short-term cardiorespiratory adaptation to high altitude (HA) exposure has not yet been studied in children, we assessed acute mountain sickness (AMS), hypoxic ventilatory response (HVR) at rest and maximal exercise capacity (CPET) at low altitude (LA) and HA in pre-pubertal children and their fathers. Twenty father-child pairs (11 ± 1 years and 44 ± 4 years) were tested at LA (450 m) and HA (3450 m) at days 1, 2, and 3 after fast ascent (HA1/2/3). HVR was measured at rest and CPET was performed on a cycle ergometer. AMS severity was mild to moderate with no differences between generations. HVR was higher in children than adults at LA and increased at HA similarly in both groups. Peak oxygen uptake (VO2 peak) relative to body weight was similar in children and adults at LA and decreased significantly by 20% in both groups at HA; maximal heart rate did not change at HA in children while it decreased by 16% in adults (P < 0.001). Changes in HVR and VO2 peak from LA to HA were correlated among the biological child-father pairs. In conclusion, cardiorespiratory adaptation to altitude seems to be at least partly hereditary. Even though children and their fathers lose similar fractions of aerobic capacity going to high altitude, the mechanisms might be different. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. High altitude pulmonary edema. Report of a case with familiar history

    International Nuclear Information System (INIS)

    Velasquez, Jurg Niederbacher; Rueda Manrique, Adriana L; Sanabria Pico, Carmen E

    1998-01-01

    We report the case of a ten years old child, who presented a high altitude pulmonary edema. His father had the same disorder ten years ago. In addition we review the physiopathology, diagnosis and management of this disease

  10. Amelioration of rCBF and PbtO2 following TBI at high altitude by hyperbaric oxygen pre-conditioning.

    Science.gov (United States)

    Hu, Shengli; Li, Fei; Luo, Haishui; Xia, Yongzhi; Zhang, Jiuquan; Hu, Rong; Cui, Gaoyu; Meng, Hui; Feng, Hua

    2010-03-01

    Hypobaric hypoxia at high altitude can lead to brain damage and pre-conditioning with hyperbaric oxygen (HBO) can reduce ischemic/hypoxic brain injury. This study investigates the effects of high altitude on traumatic brain injury (TBI) and examines the neuroprotection provided by HBO preconditioning against TBI. Rats were randomly divided into four groups: HBO pre-conditioning group (HBOP, n=10), high altitude group (HA, n=10), plain control group (PC, n=10) and plain sham operation group (sham, n=10). All groups were subjected to head trauma by weight drop device except for the sham group. Rats from each group were examined for neurological function, regional cerebral blood flow (rCBF) and brain tissue oxygen pressure (PbtO(2)) and were killed for analysis by transmission electron microscope. The score of neurological deficits in the HA group was highest, followed by the HBOP group and the PC group, respectively. Both rCBF and PbtO(2) were the lowest in the HA group. Brain morphology and structure seen via the transmission electron microscope was diminished in the HA group, while fewer pathological injuries occurred in the HBOP and PC groups. High altitude aggravates TBI significantly and HBO pre-conditioning can attenuate TBI in rats at high altitude by improvement of rCBF and PbtO(2). Pre-treatment with HBO might be beneficial for people traveling to high altitude locations.

  11. High-density amorphous ice: nucleation of nanosized low-density amorphous ice

    Science.gov (United States)

    Tonauer, Christina M.; Seidl-Nigsch, Markus; Loerting, Thomas

    2018-01-01

    The pressure dependence of the crystallization temperature of different forms of expanded high-density amorphous ice (eHDA) was scrutinized. Crystallization at pressures 0.05-0.30 GPa was followed using volumetry and powder x-ray diffraction. eHDA samples were prepared via isothermal decompression of very high-density amorphous ice at 140 K to different end pressures between 0.07-0.30 GPa (eHDA0.07-0.3). At 0.05-0.17 GPa the crystallization line T x (p) of all eHDA variants is the same. At pressures  >0.17 GPa, all eHDA samples decompressed to pressures  <0.20 GPa exhibit significantly lower T x values than eHDA0.2 and eHDA0.3. We rationalize our findings with the presence of nanoscaled low-density amorphous ice (LDA) seeds that nucleate in eHDA when it is decompressed to pressures  <0.20 GPa at 140 K. Below ~0.17 GPa, these nanosized LDA domains are latent within the HDA matrix, exhibiting no effect on T x of eHDA<0.2. Upon heating at pressures  ⩾0.17 GPa, these nanosized LDA nuclei transform to ice IX nuclei. They are favored sites for crystallization and, hence, lower T x . By comparing crystallization experiments of bulk LDA with the ones involving nanosized LDA we are able to estimate the Laplace pressure and radius of ~0.3-0.8 nm for the nanodomains of LDA. The nucleation of LDA in eHDA revealed here is evidence for the first-order-like nature of the HDA  →  LDA transition, supporting water’s liquid-liquid transition scenarios.

  12. Studies on radioactivities of dust samples in the air at high altitudes

    International Nuclear Information System (INIS)

    Kohara, Eri; Muronoi, Naohiro

    2015-01-01

    The radioactivity concentrations of airborne dust samples were studied. The samples had been collected at high altitude by the Japan Air Self-Defense Force from April 2013 to March 2014. The obtained data were used for gross beta radioactivity analysis and gamma nuclide analysis. It is shown that cesium 137 was mainly detected at the 10 km and 3 km altitude of central area of Japan in several samples. Gaseous radioiodine was not detected in all the samples. Radioactive xenon was detected but the concentration did not show significant difference to the background level. (author)

  13. Raman lidar measurement of water vapor and ice clouds associated with Asian dust layer over Tsukuba, Japan

    Science.gov (United States)

    Sakai, Tetsu; Nagai, Tomohiro; Nakazato, Masahisa; Matsumura, Takatsugu

    2004-03-01

    The vertical distributions of particle extinction, backscattering, depolarization, and water vapor mixing ratio were measured using a Raman lidar over Tsukuba (36.1°N, 140.1°E), Japan, on 23-24 April 2001. Ice clouds associated with the Asian dust layer were observed at an altitude of ~6-9 km. The relative humidities in the cloud layer were close to the ice saturation values and the temperature at the top of the cloud layer was ~-35°C, suggesting that the Asian dust acted as ice nuclei at the high temperatures. The meteorological analysis suggested that the ice-saturated region was formed near the top of the dust layer where the moist air ascended in slantwise fashion above the cold-frontal zone associated with extratropical cyclone.

  14. Glycated haemoglobin (HbA1c ) and fasting plasma glucose relationships in sea-level and high-altitude settings.

    Science.gov (United States)

    Bazo-Alvarez, J C; Quispe, R; Pillay, T D; Bernabé-Ortiz, A; Smeeth, L; Checkley, W; Gilman, R H; Málaga, G; Miranda, J J

    2017-06-01

    Higher haemoglobin levels and differences in glucose metabolism have been reported among high-altitude residents, which may influence the diagnostic performance of HbA 1c . This study explores the relationship between HbA 1c and fasting plasma glucose (FPG) in populations living at sea level and at an altitude of > 3000 m. Data from 3613 Peruvian adults without a known diagnosis of diabetes from sea-level and high-altitude settings were evaluated. Linear, quadratic and cubic regression models were performed adjusting for potential confounders. Receiver operating characteristic (ROC) curves were constructed and concordance between HbA 1c and FPG was assessed using a Kappa index. At sea level and high altitude, means were 13.5 and 16.7 g/dl (P > 0.05) for haemoglobin level; 41 and 40 mmol/mol (5.9% and 5.8%; P < 0.01) for HbA 1c ; and 5.8 and 5.1 mmol/l (105 and 91.3 mg/dl; P < 0.001) for FPG, respectively. The adjusted relationship between HbA 1c and FPG was quadratic at sea level and linear at high altitude. Adjusted models showed that, to predict an HbA 1c value of 48 mmol/mol (6.5%), the corresponding mean FPG values at sea level and high altitude were 6.6 and 14.8 mmol/l (120 and 266 mg/dl), respectively. An HbA 1c cut-off of 48 mmol/mol (6.5%) had a sensitivity for high FPG of 87.3% (95% confidence interval (95% CI) 76.5 to 94.4) at sea level and 40.9% (95% CI 20.7 to 63.6) at high altitude. The relationship between HbA 1c and FPG is less clear at high altitude than at sea level. Caution is warranted when using HbA 1c to diagnose diabetes mellitus in this setting. © 2017 The Authors. Diabetic Medicine published by John Wiley & Sons Ltd on behalf of Diabetes UK.

  15. Impact of Precipitating Ice Hydrometeors on Longwave Radiative Effect Estimated by a Global Cloud-System Resolving Model

    Science.gov (United States)

    Chen, Ying-Wen; Seiki, Tatsuya; Kodama, Chihiro; Satoh, Masaki; Noda, Akira T.

    2018-02-01

    Satellite observation and general circulation model (GCM) studies suggest that precipitating ice makes nonnegligible contributions to the radiation balance of the Earth. However, in most GCMs, precipitating ice is diagnosed and its radiative effects are not taken into account. Here we examine the longwave radiative impact of precipitating ice using a global nonhydrostatic atmospheric model with a double-moment cloud microphysics scheme. An off-line radiation model is employed to determine cloud radiative effects according to the amount and altitude of each type of ice hydrometeor. Results show that the snow radiative effect reaches 2 W m-2 in the tropics, which is about half the value estimated by previous studies. This effect is strongly dependent on the vertical separation of ice categories and is partially generated by differences in terminal velocities, which are not represented in GCMs with diagnostic precipitating ice. Results from sensitivity experiments that artificially change the categories and altitudes of precipitating ice show that the simulated longwave heating profile and longwave radiation field are sensitive to the treatment of precipitating ice in models. This study emphasizes the importance of incorporating appropriate treatments for the radiative effects of precipitating ice in cloud and radiation schemes in GCMs in order to capture the cloud radiative effects of upper level clouds.

  16. Glucose intolerance associated with hypoxia in people living at high altitudes in the Tibetan highland.

    Science.gov (United States)

    Okumiya, Kiyohito; Sakamoto, Ryota; Ishimoto, Yasuko; Kimura, Yumi; Fukutomi, Eriko; Ishikawa, Motonao; Suwa, Kuniaki; Imai, Hissei; Chen, Wenling; Kato, Emiko; Nakatsuka, Masahiro; Kasahara, Yoriko; Fujisawa, Michiko; Wada, Taizo; Wang, Hongxin; Dai, Qingxiang; Xu, Huining; Qiao, Haisheng; Ge, Ri-Li; Norboo, Tsering; Tsering, Norboo; Kosaka, Yasuyuki; Nose, Mitsuhiro; Yamaguchi, Takayoshi; Tsukihara, Toshihiro; Ando, Kazuo; Inamura, Tetsuya; Takeda, Shinya; Ishine, Masayuki; Otsuka, Kuniaki; Matsubayashi, Kozo

    2016-02-23

    To clarify the association between glucose intolerance and high altitudes (2900-4800 m) in a hypoxic environment in Tibetan highlanders and to verify the hypothesis that high altitude dwelling increases vulnerability to diabetes mellitus (DM) accelerated by lifestyle change or ageing. Cross-sectional epidemiological study on Tibetan highlanders. We enrolled 1258 participants aged 40-87 years. The rural population comprised farmers in Domkhar (altitude 2900-3800 m) and nomads in Haiyan (3000-3100 m), Ryuho (4400 m) and Changthang (4300-4800 m). Urban area participants were from Leh (3300 m) and Jiegu (3700 m). Participants were classified into six glucose tolerance-based groups: DM, intermediate hyperglycaemia (IHG), normoglycaemia (NG), fasting DM, fasting IHG and fasting NG. Prevalence of glucose intolerance was compared in farmers, nomads and urban dwellers. Effects of dwelling at high altitude or hypoxia on glucose intolerance were analysed with the confounding factors of age, sex, obesity, lipids, haemoglobin, hypertension and lifestyle, using multiple logistic regression. The prevalence of DM (fasting DM)/IHG (fasting IHG) was 8.9% (6.5%)/25.1% (12.7%), respectively, in all participants. This prevalence was higher in urban dwellers (9.5% (7.1%)/28.5% (11.7%)) and in farmers (8.5% (6.1%)/28.5% (18.3%)) compared with nomads (8.2% (5.7%)/15.7% (9.7%)) (p=0.0140/0.0001). Dwelling at high altitude was significantly associated with fasting IHG+fasting DM/fasting DM (ORs for >4500 and 3500-4499 m were 3.59/4.36 and 2.07/1.76 vs intolerance. Socioeconomic factors, hypoxaemia and the effects of altitudes >3500 m play a major role in the high prevalence of glucose intolerance in highlanders. Tibetan highlanders may be vulnerable to glucose intolerance, with polycythaemia as a sign of poor hypoxic adaptation, accelerated by lifestyle change and ageing. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please

  17. On the High Altitude Platform (HAP W-CDMA System Capacity

    Directory of Open Access Journals (Sweden)

    L. de Haro-Ariet

    2004-06-01

    Full Text Available The performance of a downlink power control model, based on a n-thpower distance law, is evaluated for high altitude platform station(HAPS W-CDMA systems. The downlink capacity using this model iscompared with the uplink capacity. It is shown that the uplink capacityis higher than the downlink capacity.

  18. Oxidative DNA damage and repair in skeletal muscle of humans exposed to high-altitude hypoxia

    International Nuclear Information System (INIS)

    Lundby, Carsten; Pilegaard, Henriette; Hall, Gerrit van; Sander, Mikael; Calbet, Jose; Loft, Steffen; Moeller, Peter

    2003-01-01

    Recent research suggests that high-altitude hypoxia may serve as a model for prolonged oxidative stress in healthy humans. In this study, we investigated the consequences of prolonged high-altitude hypoxia on the basal level of oxidative damage to nuclear DNA in muscle cells, a major oxygen-consuming tissue. Muscle biopsies from seven healthy humans were obtained at sea level and after 2 and 8 weeks of hypoxia at 4100 m.a.s.l. We found increased levels of strand breaks and endonuclease III-sensitive sites after 2 weeks of hypoxia, whereas oxidative DNA damage detected by formamidopyrimidine DNA glycosylase (FPG) protein was unaltered. The expression of 8-oxoguanine DNA glycosylase 1 (OGG1), determined by quantitative RT-PCR of mRNA levels did not significantly change during high-altitude hypoxia, although the data could not exclude a minor upregulation. The expression of heme oxygenase-1 (HO-1) was unaltered by prolonged hypoxia, in accordance with the notion that HO-1 is an acute stress response protein. In conclusion, our data indicate high-altitude hypoxia may serve as a good model for oxidative stress and that antioxidant genes are not upregulated in muscle tissue by prolonged hypoxia despite increased generation of oxidative DNA damage

  19. Atmospheric Sampling of Aerosols to Stratospheric Altitudes using High Altitude Balloons

    Science.gov (United States)

    Jerde, E. A.; Thomas, E.

    2010-12-01

    Although carbon dioxide represents a long-lived atmospheric component relevant to global climate change, it is also understood that many additional contributors influence the overall climate of Earth. Among these, short-lived components are more difficult to incorporate into models due to uncertainties in the abundances of these both spatially and temporally. Possibly the most significant of these short-lived components falls under the heading of “black carbon” (BC). There are numerous overlapping definitions of BC, but it is basically carbonaceous in nature and light absorbing. Due to its potential as a climate forcer, an understanding of the BC population in the atmosphere is critical for modeling of radiative forcing. Prior measurements of atmospheric BC generally consist of airplane- and ground-based sampling, typically below 5000 m and restricted in time and space. Given that BC has a residence time on the order of days, short-term variability is easily missed. Further, since the radiative forcing is a result of BC distributed through the entire atmospheric column, aircraft sampling is by definition incomplete. We are in the process of planning a more comprehensive sampling of the atmosphere for BC using high-altitude balloons. Balloon-borne sampling is a highly reliable means to sample air through the entire troposphere and into the lower stratosphere. Our system will incorporate a balloon and a flight train of two modules. One module will house an atmospheric sampler. This sampler will be single-stage (samples all particle sizes together), and will place particles directly on an SEM sample stub for analysis. The nozzle depositing the sample will be offset from the center of the stub, placing the aerosol particles toward the edge. At various altitudes, the stub will be rotated 45 degrees, providing 6-8 sample “cuts” of particle populations through the atmospheric column. The flights will reach approximately 27 km altitude, above which the balloons

  20. Cardiovascular Effects of Altitude on Performance Athletes.

    Science.gov (United States)

    Shah, Ankit B; Coplan, Neil

    Altitude plays an important role in cardiovascular performance and training for athletes. Whether it is mountaineers, skiers, or sea-level athletes trying to gain an edge by training or living at increased altitude, there are many potential benefits and harms of such endeavors. Echocardiographic studies done on athletes at increased altitude have shown evidence for right ventricular dysfunction and pulmonary hypertension, but no change in left ventricular ejection fraction. In addition, 10% of athletes are susceptible to pulmonary hypertension and high-altitude pulmonary edema. Some studies suggest that echocardiography may be able to identify athletes susceptible to high-altitude pulmonary edema prior to competing or training at increased altitudes. Further research is needed on the long-term effects of altitude training, as repeated, transient episodes of pulmonary hypertension and right ventricular dysfunction may have long-term implications. Current literature suggests that performance athletes are not at higher risk for ventricular arrhythmias when training or competing at increased altitudes. For sea-level athletes, the optimal strategy for attaining the benefits while minimizing the harms of altitude training still needs to be clarified, although-for now-the "live high, train low" approach appears to have the most rationale.

  1. Anti-hypotensive treatment and endothelin blockade synergistically antagonize exercise fatigue in rats under simulated high altitude.

    Directory of Open Access Journals (Sweden)

    Daniel Radiloff

    Full Text Available Rapid ascent to high altitude causes illness and fatigue, and there is a demand for effective acute treatments to alleviate such effects. We hypothesized that increased oxygen delivery to the tissue using a combination of a hypertensive agent and an endothelin receptor A antagonist drugs would limit exercise-induced fatigue at simulated high altitude. Our data showed that the combination of 0.1 mg/kg ambrisentan with either 20 mg/kg ephedrine or 10 mg/kg methylphenidate significantly improved exercise duration in rats at simulated altitude of 4,267 m, whereas the individual compounds did not. In normoxic, anesthetized rats, ephedrine alone and in combination with ambrisentan increased heart rate, peripheral blood flow, carotid and pulmonary arterial pressures, breathing rate, and vastus lateralis muscle oxygenation, but under inspired hypoxia, only the combination treatment significantly enhanced muscle oxygenation. Our results suggest that sympathomimetic agents combined with endothelin-A receptor blockers offset altitude-induced fatigue in rats by synergistically increasing the delivery rate of oxygen to hypoxic muscle by concomitantly augmenting perfusion pressure and improving capillary conductance in the skeletal muscle. Our findings might therefore serve as a basis to develop an effective treatment to prevent high-altitude illness and fatigue in humans.

  2. High Arctic Holocene temperature record from the Agassiz ice cap and Greenland ice sheet evolution.

    Science.gov (United States)

    Lecavalier, Benoit S; Fisher, David A; Milne, Glenn A; Vinther, Bo M; Tarasov, Lev; Huybrechts, Philippe; Lacelle, Denis; Main, Brittany; Zheng, James; Bourgeois, Jocelyne; Dyke, Arthur S

    2017-06-06

    We present a revised and extended high Arctic air temperature reconstruction from a single proxy that spans the past ∼12,000 y (up to 2009 CE). Our reconstruction from the Agassiz ice cap (Ellesmere Island, Canada) indicates an earlier and warmer Holocene thermal maximum with early Holocene temperatures that are 4-5 °C warmer compared with a previous reconstruction, and regularly exceed contemporary values for a period of ∼3,000 y. Our results show that air temperatures in this region are now at their warmest in the past 6,800-7,800 y, and that the recent rate of temperature change is unprecedented over the entire Holocene. The warmer early Holocene inferred from the Agassiz ice core leads to an estimated ∼1 km of ice thinning in northwest Greenland during the early Holocene using the Camp Century ice core. Ice modeling results show that this large thinning is consistent with our air temperature reconstruction. The modeling results also demonstrate the broader significance of the enhanced warming, with a retreat of the northern ice margin behind its present position in the mid Holocene and a ∼25% increase in total Greenland ice sheet mass loss (∼1.4 m sea-level equivalent) during the last deglaciation, both of which have implications for interpreting geodetic measurements of land uplift and gravity changes in northern Greenland.

  3. The Effect of Sex on Heart Rate Variability at High Altitude.

    Science.gov (United States)

    Boos, Christopher John; Vincent, Emma; Mellor, Adrian; O'Hara, John; Newman, Caroline; Cruttenden, Richard; Scott, Phylip; Cooke, Mark; Matu, Jamie; Woods, David Richard

    2017-12-01

    There is evidence suggesting that high altitude (HA) exposure leads to a fall in heart rate variability (HRV) that is linked to the development of acute mountain sickness (AMS). The effects of sex on changes in HRV at HA and its relationship to AMS are unknown. HRV (5-min single-lead ECG) was measured in 63 healthy adults (41 men and 22 women) 18-56 yr of age at sea level (SL) and during a HA trek at 3619, 4600, and 5140 m, respectively. The main effects of altitude (SL, 3619 m, 4600 m, and 5140 m) and sex (men vs women) and their potential interaction were assessed using a factorial repeated-measures ANOVA. Logistic regression analyses were performed to assess the ability of HRV to predict AMS. Men and women were of similar age (31.2 ± 9.3 vs 31.7 ± 7.5 yr), ethnicity, and body and mass index. There was main effect for altitude on heart rate, SD of normal-to-normal (NN) intervals (SDNN), root mean square of successive differences (RMSSD), number of pairs of successive NN differing by >50 ms (NN50), NN50/total number of NN, very low-frequency power, low-frequency (LF) power, high-frequency (HF) power, and total power (TP). The most consistent effect on post hoc analysis was reduction in these HRV measures between 3619 and 5140 m at HA. Heart rate was significantly lower and SDNN, RMSSD, LF power, HF power, and TP were higher in men compared with women at HA. There was no interaction between sex and altitude for any of the HRV indices measured. HRV was not predictive of AMS development. Increasing HA leads to a reduction in HRV. Significant differences between men and women emerge at HA. HRV was not predictive of AMS.

  4. Mass balance and sliding velocity of the Puget lobe of the cordilleran ice sheet during the last glaciation

    Science.gov (United States)

    Booth, D.B.

    1986-01-01

    An estimate of the sliding velocity and basal meltwater discharge of the Puget lobe of the Cordilleran ice sheet can be calculated from its reconstructed extent, altitude, and mass balance. Lobe dimensions and surface altitudes are inferred from ice limits and flow-direction indicators. Net annual mass balance and total ablation are calculated from relations empirically derived from modern maritime glaciers. An equilibrium-line altitude between 1200 and 1250 m is calculated for the maximum glacial advance (ca. 15,000 yr B.P.) during the Vashon Stade of the Fraser Glaciation. This estimate is in accord with geologic data and is insensitive to plausible variability in the parameters used in the reconstruction. Resultant sliding velocities are as much as 650 m/a at the equilibrium line, decreasing both up- and downglacier. Such velocities for an ice sheet of this size are consistent with nonsurging behavior. Average meltwater discharge increases monotonically downglacier to 3000 m3/sec at the terminus and is of a comparable magnitude to ice discharge over much of the glacier's ablation area. Palcoclimatic inferences derived from this reconstruction are consistent with previous, independently derived studies of late Pleistocene temperature and precipitation in the Pacific Northwest. ?? 1986.

  5. Effect of solar radiation (UV and visible) at high altitude on CAM-cycling and phenolic compound biosynthesis in Sedum album

    International Nuclear Information System (INIS)

    Bachereau, F.; Marigo, G.; Asta, J.

    1998-01-01

    The field experiment was carried out in order to compare the response of a CAM plant, Sedum album L., to solar radiation at a high altitude (2 100 m) with that at a low altitude location with respect to CAM and phenolic content. Treatment sites included (1) sun-exposed, low altitude, (2) sun-exposed, high altitude with different light treatments, including UV-B and UV-B + A screening, and (3) shade at high altitude. After a 70-day treatment period, CAM-cycling and phenolic compound content were analysed, and high altitude treatments were compared to the low altitude control. The sun-exposed low altitude control was characterized by CAM-cycling and a low phenolic compound content during the experiment. In plants transplanted to the high altitude, only the shaded group maintained a CAM-cycling and a phenolic compound content similar to those of the sun-exposed low altitude control. Samples under UV-B and UV-B + A filters showed similar responses, suggesting the absence of a specific UV-A radiation effect. The screening of UV-B or UV-B + A radiation allowed plants to partially maintain a CAM-cycling and induced a decrease in phenolic compound content. These responses under UV filters were, however, intermediate between those observed in sun-exposed and shaded groups. These results demonstrate a specific effect of radiation from both visible (400–800 nm) and UV-B (280–320 nm) bands on both CAM-cycling and phenolic biosynthesis in S. album L. plants. These light-dependent effects are discussed on a physiological basis and a possible interaction between CAM-cycling and phenolic metabolism is suggested. (author)

  6. [Splenic infarction at high altitude, Huaraz-Peru (3,100 masl)].

    Science.gov (United States)

    López de Guimaraes, Douglas; Menacho López, Julio; Villanueva Palacios, Jovita; Mosquera Vásquez, Vitaliano

    2009-01-01

    We report three cases of splenic infarction in healthy men for the first time that amounted to high altitudes, observed in the hospital "Victor Ramos Guardia" Huaraz (3100 m). Case 1 (1995) of 55 years, born in Cuba, from Lima, caucasian suddenly presented acute abdominal pain in epigastrium, distension, nausea and vomiting, was laparotomized for acute abdomen and surgical pathology revealed thrombosis with splenic infarction splenic artery and vein. During follow-up in Lima, hemoglobin electrophoresis showed that it was heterozygous carrier of the sickle trait (Hb A: 57% Hb S: 38.5%). Case 2 (1998) of 23 years, born in Cuba, from Lima, Black said acute abdominal pain in left hypochondrium, shortness of breath and chest pain, clinical examination and radiography of the abdomen showed the spleen volume increased. Case 3 (2006) of 17 years, natural and from Lima, mestizo, who came on tour promotion, acute abdominal pain referred onset in the epigastrium and left hypochondrium, headache, increase heat, nausea and vomiting, pharyngitis was found acute and painful, and spleen increased in size by clinical and x-ray of abdomen simple stand. None had no history of hemoglobinopathy and anemia. In general, medical management was supportive and cases 2 and 3 are recommended hemoglobin electrophoresis. We conclude that we must think of splenic infarction associated with height in any healthy person who is first at high altitude (> 3000m) and having a sudden acute abdominal pain in epigastrium and / or left hypochondrium, pain and palpable spleen and radiological study compatible with image. In this case is indicated by hemoglobin electrophoresis to determine whether there is an individual heterozygous carrier of the sickle trait. splenic infarction, high altitude, sickle trait, Huaraz.

  7. Fit for high altitude: are hypoxic challenge tests useful?

    Directory of Open Access Journals (Sweden)

    Matthys Heinrich

    2011-02-01

    Full Text Available Abstract Altitude travel results in acute variations of barometric pressure, which induce different degrees of hypoxia, changing the gas contents in body tissues and cavities. Non ventilated air containing cavities may induce barotraumas of the lung (pneumothorax, sinuses and middle ear, with pain, vertigo and hearing loss. Commercial air planes keep their cabin pressure at an equivalent altitude of about 2,500 m. This leads to an increased respiratory drive which may also result in symptoms of emotional hyperventilation. In patients with preexisting respiratory pathology due to lung, cardiovascular, pleural, thoracic neuromuscular or obesity-related diseases (i.e. obstructive sleep apnea an additional hypoxic stress may induce respiratory pump and/or heart failure. Clinical pre-altitude assessment must be disease-specific and it includes spirometry, pulsoximetry, ECG, pulmonary and systemic hypertension assessment. In patients with abnormal values we need, in addition, measurements of hemoglobin, pH, base excess, PaO2, and PaCO2 to evaluate whether O2- and CO2-transport is sufficient. Instead of the hypoxia altitude simulation test (HAST, which is not without danger for patients with respiratory insufficiency, we prefer primarily a hyperoxic challenge. The supplementation of normobaric O2 gives us information on the acute reversibility of the arterial hypoxemia and the reduction of ventilation and pulmonary hypertension, as well as about the efficiency of the additional O2-flow needed during altitude exposure. For difficult judgements the performance of the test in a hypobaric chamber with and without supplemental O2-breathing remains the gold standard. The increasing numbers of drugs to treat acute pulmonary hypertension due to altitude exposure (acetazolamide, dexamethasone, nifedipine, sildenafil or to other etiologies (anticoagulants, prostanoids, phosphodiesterase-5-inhibitors, endothelin receptor antagonists including mechanical aids to

  8. Fit for high altitude: are hypoxic challenge tests useful?

    Science.gov (United States)

    Matthys, Heinrich

    2011-02-28

    Altitude travel results in acute variations of barometric pressure, which induce different degrees of hypoxia, changing the gas contents in body tissues and cavities. Non ventilated air containing cavities may induce barotraumas of the lung (pneumothorax), sinuses and middle ear, with pain, vertigo and hearing loss. Commercial air planes keep their cabin pressure at an equivalent altitude of about 2,500 m. This leads to an increased respiratory drive which may also result in symptoms of emotional hyperventilation. In patients with preexisting respiratory pathology due to lung, cardiovascular, pleural, thoracic neuromuscular or obesity-related diseases (i.e. obstructive sleep apnea) an additional hypoxic stress may induce respiratory pump and/or heart failure. Clinical pre-altitude assessment must be disease-specific and it includes spirometry, pulsoximetry, ECG, pulmonary and systemic hypertension assessment. In patients with abnormal values we need, in addition, measurements of hemoglobin, pH, base excess, PaO2, and PaCO2 to evaluate whether O2- and CO2-transport is sufficient.Instead of the hypoxia altitude simulation test (HAST), which is not without danger for patients with respiratory insufficiency, we prefer primarily a hyperoxic challenge. The supplementation of normobaric O2 gives us information on the acute reversibility of the arterial hypoxemia and the reduction of ventilation and pulmonary hypertension, as well as about the efficiency of the additional O2-flow needed during altitude exposure. For difficult judgements the performance of the test in a hypobaric chamber with and without supplemental O2-breathing remains the gold standard. The increasing numbers of drugs to treat acute pulmonary hypertension due to altitude exposure (acetazolamide, dexamethasone, nifedipine, sildenafil) or to other etiologies (anticoagulants, prostanoids, phosphodiesterase-5-inhibitors, endothelin receptor antagonists) including mechanical aids to reduce periodical or

  9. Increasing alpine transit traffic through Switzerland will considerably enhance high altitude alpine pollutant levels

    Energy Technology Data Exchange (ETDEWEB)

    Prevot, A S.H.; Dommen, J; Furger, M; Graber, W K [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    Within the EU-Project VOTALP (Vertical Ozone Transports in the Alps), we have shown that deep alpine valleys like the Mesolcina Valley very efficiently transport air out of the polluted valley up to altitudes between 2000 and near 4000 m asl (above sea level). Pollutants emitted in these valleys are very efficiently transported up to high altitudes. (author) 2 figs., 1 tab., 2 refs.

  10. The effect of chronic erythrocytic polycythemia and high altitude upon plasma and blood volumes.

    Science.gov (United States)

    Burton, R. R.; Smith, A. H.

    1972-01-01

    Comparison of two kinds of physiological chronic erythrocytic polycythemias in order to differentiate the specific effect of erythrocytic polycythemia from the general effects of high altitude upon the plasma volume. The two kinds were produced hormonally in female chickens, at sea level, or by protracted high-altitude exposures. It appears that the vascular system of the body may account for an increase in red blood cell mass either by reduction in plasma volume, or by no change in plasma volume, resulting in differential changes in total blood volumes.

  11. Unmanned Aerial Vehicles: Progress Toward Meeting High Altitude Endurance Aircraft Price Goals

    National Research Council Canada - National Science Library

    1998-01-01

    ...) High Altitude Endurance (HAE) Unmanned Aerial Vehicle (UAV) program to determine whether the average flyaway cost for the Global Hawk and DarkStar HAE alr vehicles will be within DOD's cost goal...

  12. The glass transition in high-density amorphous ice.

    Science.gov (United States)

    Loerting, Thomas; Fuentes-Landete, Violeta; Handle, Philip H; Seidl, Markus; Amann-Winkel, Katrin; Gainaru, Catalin; Böhmer, Roland

    2015-01-01

    There has been a long controversy regarding the glass transition in low-density amorphous ice (LDA). The central question is whether or not it transforms to an ultraviscous liquid state above 136 K at ambient pressure prior to crystallization. Currently, the most widespread interpretation of the experimental findings is in terms of a transformation to a superstrong liquid above 136 K. In the last decade some work has also been devoted to the study of the glass transition in high-density amorphous ice (HDA) which is in the focus of the present review. At ambient pressure HDA is metastable against both ice I and LDA, whereas at > 0.2 GPa HDA is no longer metastable against LDA, but merely against high-pressure forms of crystalline ice. The first experimental observation interpreted as the glass transition of HDA was made using in situ methods by Mishima, who reported a glass transition temperature T g of 160 K at 0.40 GPa. Soon thereafter Andersson and Inaba reported a much lower glass transition temperature of 122 K at 1.0 GPa. Based on the pressure dependence of HDA's T g measured in Innsbruck, we suggest that they were in fact probing the distinct glass transition of very high-density amorphous ice (VHDA). Very recently the glass transition in HDA was also observed at ambient pressure at 116 K. That is, LDA and HDA show two distinct glass transitions, clearly separated by about 20 K at ambient pressure. In summary, this suggests that three glass transition lines can be defined in the p-T plane for LDA, HDA, and VHDA.

  13. A statistical study of high-altitude electric fields measured on the Viking satellite

    International Nuclear Information System (INIS)

    Lindqvist, P.A.; Marklund, G.T.

    1990-01-01

    Characteristics of high-altitude data from the Viking electric field instrument are presented in a statistical study based on 109 Viking orbits. The study is focused in particular on the signatures of and relationships between various parameters measured by the electric field instrument, such as the parallel and transverse (to B) components of the electric field instrument, such as electric field variability. A major goal of the Viking mission was to investigate the occurrence and properties of parallel electric fields and their role in the auroral acceleration process. The results in this paper on the altitude distribution of the electric field variability confirm earlier findings on the distribution of small-scale electric fields and indicate the presence of parallel fields up to about 11,000 km altitude. The directly measured parallel electric field is also investigated in some detail. It is in general directed upward with an average value of 1 mV/m, but depends on, for example, altitude and plasma density. Possible sources of error in the measurement of the parallel field are also considered and accounted for

  14. A prototype method for diagnosing high ice water content probability using satellite imager data

    Science.gov (United States)

    Yost, Christopher R.; Bedka, Kristopher M.; Minnis, Patrick; Nguyen, Louis; Strapp, J. Walter; Palikonda, Rabindra; Khlopenkov, Konstantin; Spangenberg, Douglas; Smith, William L., Jr.; Protat, Alain; Delanoe, Julien

    2018-03-01

    Recent studies have found that ingestion of high mass concentrations of ice particles in regions of deep convective storms, with radar reflectivity considered safe for aircraft penetration, can adversely impact aircraft engine performance. Previous aviation industry studies have used the term high ice water content (HIWC) to define such conditions. Three airborne field campaigns were conducted in 2014 and 2015 to better understand how HIWC is distributed in deep convection, both as a function of altitude and proximity to convective updraft regions, and to facilitate development of new methods for detecting HIWC conditions, in addition to many other research and regulatory goals. This paper describes a prototype method for detecting HIWC conditions using geostationary (GEO) satellite imager data coupled with in situ total water content (TWC) observations collected during the flight campaigns. Three satellite-derived parameters were determined to be most useful for determining HIWC probability: (1) the horizontal proximity of the aircraft to the nearest overshooting convective updraft or textured anvil cloud, (2) tropopause-relative infrared brightness temperature, and (3) daytime-only cloud optical depth. Statistical fits between collocated TWC and GEO satellite parameters were used to determine the membership functions for the fuzzy logic derivation of HIWC probability. The products were demonstrated using data from several campaign flights and validated using a subset of the satellite-aircraft collocation database. The daytime HIWC probability was found to agree quite well with TWC time trends and identified extreme TWC events with high probability. Discrimination of HIWC was more challenging at night with IR-only information. The products show the greatest capability for discriminating TWC ≥ 0.5 g m-3. Product validation remains challenging due to vertical TWC uncertainties and the typically coarse spatio-temporal resolution of the GEO data.

  15. High-density amorphous ice: A path-integral simulation

    Science.gov (United States)

    Herrero, Carlos P.; Ramírez, Rafael

    2012-09-01

    Structural and thermodynamic properties of high-density amorphous (HDA) ice have been studied by path-integral molecular dynamics simulations in the isothermal-isobaric ensemble. Interatomic interactions were modeled by using the effective q-TIP4P/F potential for flexible water. Quantum nuclear motion is found to affect several observable properties of the amorphous solid. At low temperature (T = 50 K) the molar volume of HDA ice is found to increase by 6%, and the intramolecular O-H distance rises by 1.4% due to quantum motion. Peaks in the radial distribution function of HDA ice are broadened with respect to their classical expectancy. The bulk modulus, B, is found to rise linearly with the pressure, with a slope ∂B/∂P = 7.1. Our results are compared with those derived earlier from classical and path-integral simulations of HDA ice. We discuss similarities and discrepancies with those earlier simulations.

  16. Mammals of the high altitudes of western Arunachal Pradesh, eastern Himalaya: an assessment of threats and conservation needs

    NARCIS (Netherlands)

    Mishra, C.; Madhusudan, M.D.; Datta, A.

    2006-01-01

    he high altitudes of Arunachal Pradesh, India, located in the Eastern Himalaya biodiversity hotspot, remain zoologically unexplored and unprotected. We report results of recent mammal surveys in the high altitude habitats of western Arunachal Pradesh. A total of 35 mammal species (including 12

  17. Flight simulation program for high altitude long endurance unmanned vehicle; Kokodo mujinki no hiko simulation program

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, H.; Hashidate, M. [National Aerospace Laboratory, Tokyo (Japan)

    1995-11-01

    An altitude of about 20 km has the atmospheric density too dilute for common aircraft, and the air resistance too great for satellites. Attention has been drawn in recent years on a high-altitude long-endurance unmanned vehicle that flies at this altitude for a long period of time to serve as a wave relaying base and perform traffic control. Therefore, a development was made on a flight simulation program to evaluate and discuss the guidance and control laws for the high-altitude unmanned vehicle. Equations of motion were derived for three-dimensional six freedom and three-dimensional three freedom. Aerodynamic characteristics of an unmanned vehicle having a Rectenna wing were estimated, and formulation was made according to the past research results on data of winds that the unmanned vehicle is anticipated to encounter at an altitude of 20 km. Noticing the inside of a horizontal plane, a proposal was given on a guidance law that follows a given path. A flight simulation was carried out to have attained a prospect that the unmanned vehicle may be enclosed in a limited space even if the vehicle is encountered with a relatively strong wind. 18 refs., 20 figs., 1 tab.

  18. Nike Black Brant V high altitude dynamic instability characteristics

    Science.gov (United States)

    Montag, W. H.; Walker, L. L., Jr.

    1979-01-01

    Flight experience on the Nike Black Brant V has demonstrated the existence of plume induced flow separation over the fins and aft body of the Black Brant V motor. Modelling of the forces associated with this phenomenon as well as analysis of the resultant vehicle coning motion and its effect on the velocity vector heading are presented. A summary of Nike Black Brant V flight experience with high altitude dynamic instability is included.

  19. High-Altitude Platforms — Present Situation and Technology Trends

    OpenAIRE

    d’Oliveira, Flavio Araripe; Melo, Francisco Cristovão Lourenço de; Devezas, Tessaleno Campos

    2016-01-01

    ABSTRACT High-altitude platforms (HAPs) are aircraft, usually unmanned airships or airplanes positioned above 20 km, in the stratosphere, in order to compose a telecommunications network or perform remote sensing. In the 1990 and 2000 decades, several projects were launched, but very few had continued. In 2014, 2 major Internet companies (Google and Facebook) announced investments in new HAP projects to provide Internet access in regions without communication infrastructure (terrestrial or sa...

  20. High-precision GPS autonomous platforms for sea ice dynamics and physical oceanography

    Science.gov (United States)

    Elosegui, P.; Wilkinson, J.; Olsson, M.; Rodwell, S.; James, A.; Hagan, B.; Hwang, B.; Forsberg, R.; Gerdes, R.; Johannessen, J.; Wadhams, P.; Nettles, M.; Padman, L.

    2012-12-01

    Project "Arctic Ocean sea ice and ocean circulation using satellite methods" (SATICE), is the first high-rate, high-precision, continuous GPS positioning experiment on sea ice in the Arctic Ocean. The SATICE systems collect continuous, dual-frequency carrier-phase GPS data while drifting on sea ice. Additional geophysical measurements also collected include ocean water pressure, ocean surface salinity, atmospheric pressure, snow-depth, air-ice-ocean temperature profiles, photographic imagery, and others, enabling sea ice drift, freeboard, weather, ice mass balance, and sea-level height determination. Relatively large volumes of data from each buoy are streamed over a satellite link to a central computer on the Internet in near real time, where they are processed to estimate the time-varying buoy positions. SATICE system obtains continuous GPS data at sub-minute intervals with a positioning precision of a few centimetres in all three dimensions. Although monitoring of sea ice motions goes back to the early days of satellite observations, these autonomous platforms bring out a level of spatio-temporal detail that has never been seen before, especially in the vertical axis. These high-resolution data allows us to address new polar science questions and challenge our present understanding of both sea ice dynamics and Arctic oceanography. We will describe the technology behind this new autonomous platform, which could also be adapted to other applications that require high resolution positioning information with sustained operations and observations in the polar marine environment, and present results pertaining to sea ice dynamics and physical oceanography.

  1. Long-Term Intermittent Work at High Altitude: Right Heart Functional and Morphological Status and Associated Cardiometabolic Factors.

    Science.gov (United States)

    Brito, Julio; Siques, Patricia; López, Rosario; Romero, Raul; León-Velarde, Fabiola; Flores, Karen; Lüneburg, Nicole; Hannemann, Juliane; Böger, Rainer H

    2018-01-01

    Background: Living at high altitude or with chronic hypoxia implies functional and morphological changes in the right ventricle and pulmonary vasculature with a 10% prevalence of high-altitude pulmonary hypertension (HAPH). The implications of working intermittently (day shifts) at high altitude (hypobaric hypoxia) over the long term are still not well-defined. The aim of this study was to evaluate the right cardiac circuit status along with potentially contributory metabolic variables and distinctive responses after long exposure to the latter condition. Methods: A cross-sectional study of 120 healthy miners working at an altitude of 4,400-4,800 m for over 5 years in 7-day commuting shifts was designed. Echocardiography was performed on day 2 at sea level. Additionally, biomedical and biochemical variables, Lake Louise scores (LLSs), sleep disturbances and physiological variables were measured at altitude and at sea level. Results: The population was 41.8 ± 0.7 years old, with an average of 14 ± 0.5 (range 5-29) years spent at altitude. Most subjects still suffered from mild to moderate symptoms of acute mountain sickness (mild was an LLS of 3-5 points, including cephalea; moderate was LLS of 6-10 points) (38.3%) at the end of day 1 of the shift. Echocardiography showed a 23% mean pulmonary artery pressure (mPAP) >25 mmHg, 9% HAPH (≥30 mmHg), 85% mild increase in right ventricle wall thickness (≥5 mm), 64% mild right ventricle dilation, low pulmonary vascular resistance (PVR) and fairly good ventricle performance. Asymmetric dimethylarginine (ADMA) (OR 8.84 (1.18-66.39); p Working intermittently at high altitude involves a distinctive pattern. The most relevant and novel characteristics are a greater prevalence of elevated mPAP and HAPH than previously reported at chronic intermittent hypobaric hypoxia (CIHH), which is accompanied by subsequent morphological characteristics. These findings are associated with cardiometabolic factors (insulin and ADMA

  2. The role of ice dynamics in shaping vegetation in flowing waters.

    Science.gov (United States)

    Lind, Lovisa; Nilsson, Christer; Polvi, Lina E; Weber, Christine

    2014-11-01

    Ice dynamics is an important factor affecting vegetation in high-altitude and high-latitude streams and rivers. During the last few decades, knowledge about ice in streams and rivers has increased significantly and a respectable body of literature is now available. Here we review the literature on how ice dynamics influence riparian and aquatic vegetation. Traditionally, plant ecologists have focused their studies on the summer period, largely ignoring the fact that processes during winter also impact vegetation dynamics. For example, the freeze-up period in early winter may result in extensive formation of underwater ice that can restructure the channel, obstruct flow, and cause flooding and thus formation of more ice. In midwinter, slow-flowing reaches develop a surface-ice cover that accumulates snow, protecting habitats under the ice from formation of underwater ice but also reducing underwater light, thus suppressing photosynthesis. Towards the end of winter, ice breaks up and moves downstream. During this transport, ice floes can jam up and cause floods and major erosion. The magnitudes of the floods and their erosive power mainly depend on the size of the watercourse, also resulting in different degrees of disturbance to the vegetation. Vegetation responds both physically and physiologically to ice dynamics. Physical action involves the erosive force of moving ice and damage caused by ground frost, whereas physiological effects - mostly cell damage - happen as a result of plants freezing into the ice. On a community level, large magnitudes of ice dynamics seem to favour species richness, but can be detrimental for individual plants. Human impacts, such as flow regulation, channelisation, agriculturalisation and water pollution have modified ice dynamics; further changes are expected as a result of current and predicted future climate change. Human impacts and climate change can both favour and disfavour riverine vegetation dynamics. Restoration of streams

  3. Propagation and Breaking at High Altitudes of Gravity Waves Excited by Tropospheric Forcing

    Science.gov (United States)

    Prusa, Joseph M.; Smolarkiewicz, Piotr K.; Garcia, Rolando R.

    1996-01-01

    An anelastic approximation is used with a time-variable coordinate transformation to formulate a two-dimensional numerical model that describes the evolution of gravity waves. The model is solved using a semi-Lagrangian method with monotone (nonoscillatory) interpolation of all advected fields. The time-variable transformation is used to generate disturbances at the lower boundary that approximate the effect of a traveling line of thunderstorms (a squall line) or of flow over a broad topographic obstacle. The vertical propagation and breaking of the gravity wave field (under conditions typical of summer solstice) is illustrated for each of these cases. It is shown that the wave field at high altitudes is dominated by a single horizontal wavelength; which is not always related simply to the horizontal dimension of the source. The morphology of wave breaking depends on the horizontal wavelength; for sufficiently short waves, breaking involves roughly one half of the wavelength. In common with other studies, it is found that the breaking waves undergo "self-acceleration," such that the zonal-mean intrinsic frequency remains approximately constant in spite of large changes in the background wind. It is also shown that many of the features obtained in the calculations can be understood in terms of linear wave theory. In particular, linear theory provides insights into the wavelength of the waves that break at high altitudes, the onset and evolution of breaking. the horizontal extent of the breaking region and its position relative to the forcing, and the minimum and maximum altitudes where breaking occurs. Wave breaking ceases at the altitude where the background dissipation rate (which in our model is a proxy for molecular diffusion) becomes greater than the rate of dissipation due to wave breaking, This altitude, in effect, the model turbopause, is shown to depend on a relatively small number of parameters that characterize the waves and the background state.

  4. Climate Variability, Melt-Flow Acceleration, and Ice Quakes at the Western Slope of the Greenland Ice Sheet

    Science.gov (United States)

    Steffen, K.; Zwally, J. H.; Rial, J. A.; Behar, A.; Huff, R.

    2006-12-01

    The Greenland ice sheet experienced surface melt increase over the past 15 years with record melt years in 1987, 1991, 1998, 2002 and 2005. For the western part of the ice sheet the melt area increased by 30 percent (1979-2005). Monthly mean air temperatures increased in spring and fall by 0.23 deg. C per year since 1990, extending the length of melt and total ablation. Winter air temperatures increased by as much as 0.5 deg. C per year during the past 15 years. The equilibrium line altitude ranged between 400 and 1530 m above sea level at 70 deg. north along the western slope of the ice sheet for the past 15 years, equaling a horizontal distance of 100 km. The ELA has been below the Swiss Camp (1100 m elevation) in the nineties, and since 1997 moved above the Swiss Camp height. An increase in ELA leads to an increase in melt water run-off which has been verified by regional model studies (high-resolution re-analysis). Interannual variability of snow accumulation varies from 0.3 to 2.0 m, whereas snow and ice ablation ranges from 0 to 1.5 m water equivalent at Swiss Camp during 1990-2005. A GPS network (10 stations) monitors ice velocity, acceleration, and surface height change at high temporal resolution throughout the year. The network covers a range of 500 and 1500 m above sea level, close to the Ilulissat Icefjord World Heritage region. The ice sheet continued to accelerate during the height of the melt season with short-term velocity increases up to 100 percent, and vertical uplift rates of 0.5 m. There seems to be a good correlation between the change in ice velocity and total surface melt, suggesting that melt water penetrates to great depth through moulins and cracks, lubricating the bottom of the ice sheet. A new bore-hole video movie will be shown from a 110 m deep moulin close to Swiss Camp. A PASSCAL array of 10 portable, 3-component seismic stations deployed around Swiss Camp from May to August 2006 detected numerous microearthquakes within the ice

  5. Preventing High Altitude Cerebral Edema in Rats with Repurposed Anti-Angiogenesis Pharmacotherapy.

    Science.gov (United States)

    Tarshis, Samantha; Maltzahn, Joanne; Loomis, Zoe; Irwin, David C

    2016-12-01

    High altitude cerebral edema (HACE) is a fulminant, deadly, and yet still unpredictable brain disease. A new prophylactic treatment for HACE and its predecessor, acute mountain sickness (AMS), needs to be developed without the contraindications or adverse effect profiles of acetazolamide and dexamethasone. Since neovascularization signals are likely key contributors to HACE/AMS, our approach was to examine already existing anti-angiogenic drugs to inhibit potential initiating HACE pathway(s). This approach can also reveal crucial early steps in the frequently debated mechanism of HACE/AMS pathogenesis. We exposed four rat cohorts to hypobaric hypoxia and one to sea level (hyperbaric) conditions. The cohorts were treated with saline controls, an anti-angiogenesis drug (motesanib), a pro-angiogenesis drug (deferoxamine), or an intraperitoneal version of the established AMS prophylaxis drug, acetazolamide (benzolamide). Brain tissue was analyzed for cerebrovascular leak using the Evans Blue Dye (EVBD) protocol. We observed significantly increased EVBD in the altitude control and pro-angiogenesis (deferoxamine) cohorts, and significantly decreased EVBD in the anti-angiogenesis (motesanib), established treatment (benzolamide), and sea-level cohorts. Anti-angiogenesis-treated cohorts demonstrated less cerebrovascular extravasation than the altitude control and pro-angiogenesis treated rats, suggesting promise as an alternative prophylactic HACE/AMS treatment. The leak exacerbation with pro-angiogenesis treatment and improvement with anti-angiogenesis treatment support the hypothesis of early neovascularization signals provoking HACE. We demonstrate statistically significant evidence to guide further investigation for VEGF- and HIF-inhibitors as HACE/AMS prophylaxis, and as elucidators of still unknown HACE pathogenesis.Tarshis S, Maltzahn J, Loomis Z, Irwin DC. Preventing high altitude cerebral edema in rats with repurposed anti-angiogenesis pharmacotherapy. Aerosp Med

  6. High interannual variability of sea ice thickness in the Arctic region.

    Science.gov (United States)

    Laxon, Seymour; Peacock, Neil; Smith, Doug

    2003-10-30

    Possible future changes in Arctic sea ice cover and thickness, and consequent changes in the ice-albedo feedback, represent one of the largest uncertainties in the prediction of future temperature rise. Knowledge of the natural variability of sea ice thickness is therefore critical for its representation in global climate models. Numerical simulations suggest that Arctic ice thickness varies primarily on decadal timescales owing to changes in wind and ocean stresses on the ice, but observations have been unable to provide a synoptic view of sea ice thickness, which is required to validate the model results. Here we use an eight-year time-series of Arctic ice thickness, derived from satellite altimeter measurements of ice freeboard, to determine the mean thickness field and its variability from 65 degrees N to 81.5 degrees N. Our data reveal a high-frequency interannual variability in mean Arctic ice thickness that is dominated by changes in the amount of summer melt, rather than by changes in circulation. Our results suggest that a continued increase in melt season length would lead to further thinning of Arctic sea ice.

  7. High-altitude hypoxia as a therapeutic factor in the management of X-ray and cytostatic lymphocytopenias in cancer patients

    International Nuclear Information System (INIS)

    Kulish, u.P.; Galkina, K.A.; Karabekova, Z.K.; Kudryavtsev, V.I.; Gudi, T.P.

    1984-01-01

    An attempt is made to clarify possibilities of high-altitude conditions use in clinics to restore hematological indices deteriorating as a result of antitumoral radiation or cytostatic therapy. Using conventional methods the content of hemoglobin, the number of erythrocytes and leukocytes, leukocytic formula in the blood of patients have been determined. Using the method of hemocultures the ability of the blood serum to affect leukocyte migration of practically healthy people (donors) has been studied and by the method of amperometric titration the content of SH-groups in the blood is determined. In patients examined under high-altitude conditions the content of hemoglobin and the number of erythrocytes in blood increased, the level of total SH-groups of blood also grew. Blood serum of patients with the expressed lymphocytopenia instead of suppressing effect on leukocyte migration, observed under low-altitude conditions (Frunze), under high-altitude conditions attained the ability to increase leukocyte migration. The conclusion is made that high-altitude hypoxia is a positive factor in the treatment of radiation and cytostatic lymphopenias in cancer patients

  8. High-altitude diving in river otters: coping with combined hypoxic stresses.

    Science.gov (United States)

    Crait, Jamie R; Prange, Henry D; Marshall, Noah A; Harlow, Henry J; Cotton, Clark J; Ben-David, Merav

    2012-01-15

    River otters (Lontra canadensis) are highly active, semi-aquatic mammals indigenous to a range of elevations and represent an appropriate model for assessing the physiological responses to diving at altitude. In this study, we performed blood gas analyses and compared blood chemistry of river otters from a high-elevation (2357 m) population at Yellowstone Lake with a sea-level population along the Pacific coast. Comparisons of oxygen dissociation curves (ODC) revealed no significant difference in hemoglobin-oxygen (Hb-O(2)) binding affinity between the two populations - potentially because of demands for tissue oxygenation. Instead, high-elevation otters had greater Hb concentrations (18.7 g dl(-1)) than sea-level otters (15.6 g dl(-1)). Yellowstone otters displayed higher levels of the vasodilator nitric oxide (NO), and half the concentration of the serum protein albumin, possibly to compensate for increased blood viscosity. Despite compensation in several hematological and serological parameters, theoretical aerobic dive limits (ADL) were similar between high-elevation and sea-level otters because of the lower availability of O(2) at altitude. Our results suggest that recent disruptions to the Yellowstone Lake food web could be detrimental to otters because at this high elevation, constraints on diving may limit their ability to switch to prey in a deep-water environment.

  9. [Physical performance of older adults living in rural areas at sea level and at high altitude in Peru].

    Science.gov (United States)

    Estela-Ayamamani, David; Espinoza-Figueroa, Jossué; Columbus-Morales, Mauricio; Runzer-Colmenares, Fernando; Parodi, José F; Mayta-Tristán, Percy

    2015-01-01

    Living at high altitudes requires the inhabitants to adapt biologically and socially to the environment. The objective of this study was to determine the difference in physical performance (PP) in rural populations at sea level and at high altitude. A cross-sectional study was conducted in rural communities in Ancash, Peru, located at 3.345 meters above sea level (m.a.s.l.) and also in communities located in coastal areas at 6m.a.s.l. PP was measured by the Short Physical Performance Battery (SPPB) and other associated factors. Adjusted prevalence ratios (aPR) were calculated. A total of 130 older adults were assessed in the high altitude communities and 129 on the coast. The median age was 71.4 years, and 55.6% were female. Low physical performance (SPPB ≤ 6) was 10.0% at high altitude and 19.4% on the coast (p<0.05). Factors associated with low physical performance were residing at the coast (aPR: 2.10, 95% CI 1.02 to 4.33), self-reported poor health (aPR: 2.48, 95% CI 1.21 -5.08), hypertension (aPR: 1.73, 95% CI 1.01 to 2.98), and age (aPR: 1.04, 95% CI 1.01 to 1.07), while being a farmer (aPR: 0.49, 95% CI 0.25 to 0.97), and being independent (aPR: 0.37, 95% CI 0,20-, 072) were found to be protective factors. It was also found that the inhabitants of the coast have a mean of 0.86 points lower total SPPB than the high altitude ones (p=0.004). There is an association between altitude of residence and PP in older adults. The prevalence of a low PP in older adults in rural areas at sea level is twice as high compared to those living in high altitude rural communities. Copyright © 2014 SEGG. Published by Elsevier Espana. All rights reserved.

  10. Radiation Safety Issues in High Altitude Commercial Aircraft

    Science.gov (United States)

    Wilson, John W.; Cucinotta, Francis A.; Shinn, Judy L.

    1995-01-01

    The development of a global economy makes the outlook for high speed commercial intercontinental flight feasible, and the development of various configurations operating from 20 to 30 km have been proposed. In addition to the still unresolved issues relating to current commercial operations (12-16 km), the higher dose rates associated with the higher operating altitudes makes il imperative that the uncertainties in the atmospheric radiation environment and the associated health risks be re-examined. Atmospheric radiation associated with the galactic cosmic rays forms a background level which may, under some circumstances, exceed newly recommended allowable exposure limits proposed on the basis of recent evaluations of the A -bomb survivor data (due to increased risk coefficients). These larger risk coefficients, within the context of the methodology for estimating exposure limits, are resulting in exceedingly low estimated allowable exposure limits which may impact even present day flight operations and was the reason for the CEC workshop in Luxembourg (1990). At higher operating altitudes, solar particles events can produce exposures many orders of magnitude above background levels and pose significant health risks to the most sensitive individuals (such as during pregnancy). In this case the appropriate quality factors are undefined, and some evidence exists which indicates that the quality factor for stochastic effects is a substantial underestimate.

  11. Isolated psychosis during exposure to very high and extreme altitude - characterisation of a new medical entity.

    Science.gov (United States)

    Hüfner, Katharina; Brugger, Hermann; Kuster, Eva; Dünsser, Franziska; Stawinoga, Agnieszka E; Turner, Rachel; Tomazin, Iztok; Sperner-Unterweger, Barbara

    2017-12-05

    Psychotic episodes during exposure to very high or extreme altitude have been frequently reported in mountain literature, but not systematically analysed and acknowledged as a distinct clinical entity. Episodes reported above 3500 m altitude with possible psychosis were collected from the lay literature and provide the basis for this observational study. Dimensional criteria of the Diagnostic and Statistical Manual of Mental Disorders were used for psychosis, and the Lake Louise Scoring criteria for acute mountain sickness and high-altitude cerebral oedema (HACE). Eighty-three of the episodes collected underwent a cluster analysis to identify similar groups. Ratings were done by two independent, trained researchers (κ values 0.6-1). Findings Cluster 1 included 51% (42/83) episodes without psychosis; cluster 2 22% (18/83) cases with psychosis, plus symptoms of HACE or mental status change from other origins; and cluster 3 28% (23/83) episodes with isolated psychosis. Possible risk factors of psychosis and associated somatic symptoms were analysed between the three clusters and revealed differences regarding the factors 'starvation' (χ2 test, p = 0.002), 'frostbite' (p = 0.024) and 'supplemental oxygen' (p = 0.046). Episodes with psychosis were reversible but associated with near accidents and accidents (p = 0.007, odds ratio 4.44). Episodes of psychosis during exposure to high altitude are frequently reported, but have not been specifically examined or assigned to medical diagnoses. In addition to the risk of suffering from somatic mountain illnesses, climbers and workers at high altitude should be aware of the potential occurrence of psychotic episodes, the associated risks and respective coping strategies.

  12. High-frequency and meso-scale winter sea-ice variability in the Southern Ocean in a high-resolution global ocean model

    Science.gov (United States)

    Stössel, Achim; von Storch, Jin-Song; Notz, Dirk; Haak, Helmuth; Gerdes, Rüdiger

    2018-03-01

    This study is on high-frequency temporal variability (HFV) and meso-scale spatial variability (MSV) of winter sea-ice drift in the Southern Ocean simulated with a global high-resolution (0.1°) sea ice-ocean model. Hourly model output is used to distinguish MSV characteristics via patterns of mean kinetic energy (MKE) and turbulent kinetic energy (TKE) of ice drift, surface currents, and wind stress, and HFV characteristics via time series of raw variables and correlations. We find that (1) along the ice edge, the MSV of ice drift coincides with that of surface currents, in particular such due to ocean eddies; (2) along the coast, the MKE of ice drift is substantially larger than its TKE and coincides with the MKE of wind stress; (3) in the interior of the ice pack, the TKE of ice drift is larger than its MKE, mostly following the TKE pattern of wind stress; (4) the HFV of ice drift is dominated by weather events, and, in the absence of tidal currents, locally and to a much smaller degree by inertial oscillations; (5) along the ice edge, the curl of the ice drift is highly correlated with that of surface currents, mostly reflecting the impact of ocean eddies. Where ocean eddies occur and the ice is relatively thin, ice velocity is characterized by enhanced relative vorticity, largely matching that of surface currents. Along the ice edge, ocean eddies produce distinct ice filaments, the realism of which is largely confirmed by high-resolution satellite passive-microwave data.

  13. High altitude agriculture in the Titicaca basin (800 BCE-200 CE): Impacts on nutrition and disease load.

    Science.gov (United States)

    Juengst, Sara L; Hutchinson, Dale L; Chávez, Sergio J

    2017-07-08

    This study investigates the biological impacts of sedentism and agriculture on humans living in the high altitude landscape of the Titicaca Basin between 800 BCE and CE 200. The transition to agriculture in other global areas resulted in increases in disease and malnutrition; the high altitude of the Titicaca Basin could have exacerbated this. Our objective is to test whether the high altitude of the Titicaca Basin created a marginal environment for early agriculturalists living there, reflected through elevated rates of malnutrition and/or disease. To test this, we analyzed human remains excavated from seven archaeological sites on the Copacabana Peninsula for markers of diet and disease. These markers included dental caries, dental abscesses, cribra orbitalia, porotic hyperostosis, periosteal reactions, osteomyelitis, and linear enamel hypoplasia. Results showed that markers of diet did not support malnutrition or micronutrient deficiencies but instead, indicated a relatively diverse diet for all individuals. Markers of disease also did not vary significantly but were common, indicating circulation of pathogens or chronic bodily stress. We interpret these results as an indication that while diets remained nutritious, investment in the landscape exposed populations to issues of sanitation and disease. The high-altitude of the Titicaca Basin did not exacerbate the biological impacts of agriculture in terms of increased malnutrition. Additionally, disease load was likely related to problems faced by many sedentary groups as opposed to unique challenges posed by high altitude. In sum, despite the high elevation, the Titicaca Basin is not truly a marginal environment for humans. © 2017 Wiley Periodicals, Inc.

  14. Three plasma metabolite signatures for diagnosing high altitude pulmonary edema

    Science.gov (United States)

    Guo, Li; Tan, Guangguo; Liu, Ping; Li, Huijie; Tang, Lulu; Huang, Lan; Ren, Qian

    2015-10-01

    High-altitude pulmonary edema (HAPE) is a potentially fatal condition, occurring at altitudes greater than 3,000 m and affecting rapidly ascending, non-acclimatized healthy individuals. However, the lack of biomarkers for this disease still constitutes a bottleneck in the clinical diagnosis. Here, ultra-high performance liquid chromatography coupled with Q-TOF mass spectrometry was applied to study plasma metabolite profiling from 57 HAPE and 57 control subjects. 14 differential plasma metabolites responsible for the discrimination between the two groups from discovery set (35 HAPE subjects and 35 healthy controls) were identified. Furthermore, 3 of the 14 metabolites (C8-ceramide, sphingosine and glutamine) were selected as candidate diagnostic biomarkers for HAPE using metabolic pathway impact analysis. The feasibility of using the combination of these three biomarkers for HAPE was evaluated, where the area under the receiver operating characteristic curve (AUC) was 0.981 and 0.942 in the discovery set and the validation set (22 HAPE subjects and 22 healthy controls), respectively. Taken together, these results suggested that this composite plasma metabolite signature may be used in HAPE diagnosis, especially after further investigation and verification with larger samples.

  15. Climatic changes at high altitudes from C-14 dating at the discovery site of the Iceman Oetzi

    International Nuclear Information System (INIS)

    Kutschera, W.; Jettmar, B.; Golser, R.; Priller, A.; Puchegger, S.; Steier, P.; Wild, E.M.; Bortenschlager, S.; Oeggl, K.; Rom, W.

    2002-01-01

    An extraordinary archaeological discovery was made in 1991 at a high-altitude mountain pass (Tisenjoch, 3120 m) of the Oetztal Alps near the Austrian-Italian Border. Two mountain hikers accidentally found the body of a man sticking half-way out from a shallow ice-filled depression. Unusual climatic conditions had partly freed the body from his icy grave, where he apparently had rested for thousands of years. Radiocarbon dating of bone and tissue of the Iceman 'Oetzi' - as he was quickly nicknamed - revealed that he had lived some 5200 years ago. This established Oetzi as the oldest well-preserved body from the Neolithic period. In addition to the body, a variety of equipment was found at the site, most of it dating to the same time period. A collection of this and other measurements with emphasis on the environment of the Iceman can be found in. The Iceman story with emphasis on 14 C dating is summarized in. Recently, we dated a variety of materials found at the discovery site of the Iceman with 14 C AMS at the Vienna Environmental Research Accelerator (VERA). Among these materials there are plant remains which grow at high altitudes when the conditions are favorable. They thus serve as sensitive indicators of climatic conditions. The 14 C dates cover a time range from approximately 6000 to 4000 years ago, and give first hints on how the climatic conditions may have changed at the Iceman discovery site during this period of time. Combining this with materials found at the site which must have been brought there by animals and/or humans, the 14 C dates support the general hypothesis that in ancient times people in this region first populated high-altitude areas of the Alps above the timber line, since there they found natural pastures for domesticated animals. It is likely that these first settlers approached the Alps from the south, which also seems to be the direction from which the Iceman came to the Tisenjoch.. In this paper we will summarize our current ideas

  16. Altitude Stress During Participation of Medical Congress

    Science.gov (United States)

    Kim, Soon Bae; Kim, Jong Sung; Kim, Sang Jun; Cho, Su Hee

    2016-01-01

    Medical congresses often held in highlands. We reviewed several medical issues associated with altitude stress especially while physicians have participated medical congress held in high altitude. Altitude stress, also known as an acute mountain sickness (AMS), is caused by acute exposure to low oxygen level at high altitude which is defined as elevations at or above 1,200 m and AMS commonly occurs above 2,500 m. Altitude stress with various symptoms including insomnia can also be experienced in airplane. AMS and drunken state share many common features in symptoms, neurologic manifestations and even show multiple microbleeds in corpus callosum and white matter on MRI. Children are more susceptible to altitude stress than adults. Gradual ascent is the best method for the prevention of altitude stress. Adequate nutrition (mainly carbohydrates) and hydration are recommended. Consumption of alcohol can exacerbate the altitude-induced impairments in judgment and the visual senses and promote psychomotor dysfunction. For prevention or treatment of altitude stress, acetazolamide, phosphodiesterase inhibitors, dexamethasone and erythropoietin are helpful. Altitude stress can be experienced relatively often during participation of medical congress. It is necessary to remind the harmful effect of AMS because it can cause serious permanent organ damage even though the symptoms are negligible in most cases. PMID:27621942

  17. Electromagnetic coupling of high-altitude, nuclear electromagnetic pulses

    International Nuclear Information System (INIS)

    Anon.

    1984-01-01

    We have used scale models to measure the predicted coupling of electromagnetic fields simulating the effects of high-altitude nuclear electromagnetic pulses (HEMP) on the interior surfaces of electronic components. Predictive tools for exterior coupling are adequate. For interior coupling, however, such tools are in their infancy. Our methodological approach combines analytical, computational, and laboratory techniques in a complementary way to take advantage of their separate strengths. Computer models are a promising tool, as they can be used to treat complex objects with arbitrary shapes, dielectrics, and cables, and multiple apertures. Laboratory tests can expand the domain of investigation even further

  18. The yak genome and adaptation to life at high altitude

    DEFF Research Database (Denmark)

    Qiu, Qiang; Zhang, Guojie; Ma, Tao

    2012-01-01

    . Here, we present the draft genome sequence of a female domestic yak generated using Illumina-based technology at 65-fold coverage. Genomic comparisons between yak and cattle identify an expansion in yak of gene families related to sensory perception and energy metabolism, as well as an enrichment...... important implications for understanding adaptation to high altitude in other animal species and for hypoxia-related diseases in humans....

  19. Long-range-transported bioaerosols captured in snow cover on Mount Tateyama, Japan: impacts of Asian-dust events on airborne bacterial dynamics relating to ice-nucleation activities

    Directory of Open Access Journals (Sweden)

    T. Maki

    2018-06-01

    Full Text Available The westerly wind travelling at high altitudes over eastern Asia transports aerosols from the Asian deserts and urban areas to downwind areas such as Japan. These long-range-transported aerosols include not only mineral particles but also microbial particles (bioaerosols, that impact the ice-cloud formation processes as ice nuclei. However, the detailed relations of airborne bacterial dynamics to ice nucleation in high-elevation aerosols have not been investigated. Here, we used the aerosol particles captured in the snow cover at altitudes of 2450 m on Mt Tateyama to investigate sequential changes in the ice-nucleation activities and bacterial communities in aerosols and elucidate the relationships between the two processes. After stratification of the snow layers formed on the walls of a snow pit on Mt Tateyama, snow samples, including aerosol particles, were collected from 70 layers at the lower (winter accumulation and upper (spring accumulation parts of the snow wall. The aerosols recorded in the lower parts mainly came from Siberia (Russia, northern Asia and the Sea of Japan, whereas those in the upper parts showed an increase in Asian dust particles originating from the desert regions and industrial coasts of Asia. The snow samples exhibited high levels of ice nucleation corresponding to the increase in Asian dust particles. Amplicon sequencing analysis using 16S rRNA genes revealed that the bacterial communities in the snow samples predominately included plant associated and marine bacteria (phyla Proteobacteria during winter, whereas during spring, when dust events arrived frequently, the majority were terrestrial bacteria of phyla Actinobacteria and Firmicutes. The relative abundances of Firmicutes (Bacilli showed a significant positive relationship with the ice nucleation in snow samples. Presumably, Asian dust events change the airborne bacterial communities over Mt Tateyama and carry terrestrial bacterial populations, which

  20. Long-range-transported bioaerosols captured in snow cover on Mount Tateyama, Japan: impacts of Asian-dust events on airborne bacterial dynamics relating to ice-nucleation activities

    Science.gov (United States)

    Maki, Teruya; Furumoto, Shogo; Asahi, Yuya; Lee, Kevin C.; Watanabe, Koichi; Aoki, Kazuma; Murakami, Masataka; Tajiri, Takuya; Hasegawa, Hiroshi; Mashio, Asami; Iwasaka, Yasunobu

    2018-06-01

    The westerly wind travelling at high altitudes over eastern Asia transports aerosols from the Asian deserts and urban areas to downwind areas such as Japan. These long-range-transported aerosols include not only mineral particles but also microbial particles (bioaerosols), that impact the ice-cloud formation processes as ice nuclei. However, the detailed relations of airborne bacterial dynamics to ice nucleation in high-elevation aerosols have not been investigated. Here, we used the aerosol particles captured in the snow cover at altitudes of 2450 m on Mt Tateyama to investigate sequential changes in the ice-nucleation activities and bacterial communities in aerosols and elucidate the relationships between the two processes. After stratification of the snow layers formed on the walls of a snow pit on Mt Tateyama, snow samples, including aerosol particles, were collected from 70 layers at the lower (winter accumulation) and upper (spring accumulation) parts of the snow wall. The aerosols recorded in the lower parts mainly came from Siberia (Russia), northern Asia and the Sea of Japan, whereas those in the upper parts showed an increase in Asian dust particles originating from the desert regions and industrial coasts of Asia. The snow samples exhibited high levels of ice nucleation corresponding to the increase in Asian dust particles. Amplicon sequencing analysis using 16S rRNA genes revealed that the bacterial communities in the snow samples predominately included plant associated and marine bacteria (phyla Proteobacteria) during winter, whereas during spring, when dust events arrived frequently, the majority were terrestrial bacteria of phyla Actinobacteria and Firmicutes. The relative abundances of Firmicutes (Bacilli) showed a significant positive relationship with the ice nucleation in snow samples. Presumably, Asian dust events change the airborne bacterial communities over Mt Tateyama and carry terrestrial bacterial populations, which possibly induce ice

  1. High-resolution ice thickness and bed topography of a land-terminating section of the Greenland Ice Sheet

    DEFF Research Database (Denmark)

    Lindbäck, K.; Pettersson, R.; Doyle, S. H.

    2014-01-01

    We present ice thickness and bed topography maps with high spatial resolution (250 to 500 m) of a and-terminating section of the Greenland Ice Sheet derived from combined ground-based and airborne radar surveys. The data have a total area of ~12000 km2 and cover the whole ablation area of the out...

  2. Long-Term Intermittent Work at High Altitude: Right Heart Functional and Morphological Status and Associated Cardiometabolic Factors

    Directory of Open Access Journals (Sweden)

    Julio Brito

    2018-03-01

    Full Text Available Background: Living at high altitude or with chronic hypoxia implies functional and morphological changes in the right ventricle and pulmonary vasculature with a 10% prevalence of high-altitude pulmonary hypertension (HAPH. The implications of working intermittently (day shifts at high altitude (hypobaric hypoxia over the long term are still not well-defined. The aim of this study was to evaluate the right cardiac circuit status along with potentially contributory metabolic variables and distinctive responses after long exposure to the latter condition.Methods: A cross-sectional study of 120 healthy miners working at an altitude of 4,400–4,800 m for over 5 years in 7-day commuting shifts was designed. Echocardiography was performed on day 2 at sea level. Additionally, biomedical and biochemical variables, Lake Louise scores (LLSs, sleep disturbances and physiological variables were measured at altitude and at sea level.Results: The population was 41.8 ± 0.7 years old, with an average of 14 ± 0.5 (range 5–29 years spent at altitude. Most subjects still suffered from mild to moderate symptoms of acute mountain sickness (mild was an LLS of 3–5 points, including cephalea; moderate was LLS of 6–10 points (38.3% at the end of day 1 of the shift. Echocardiography showed a 23% mean pulmonary artery pressure (mPAP >25 mmHg, 9% HAPH (≥30 mmHg, 85% mild increase in right ventricle wall thickness (≥5 mm, 64% mild right ventricle dilation, low pulmonary vascular resistance (PVR and fairly good ventricle performance. Asymmetric dimethylarginine (ADMA (OR 8.84 (1.18–66.39; p < 0.05 and insulin (OR: 1.11 (1.02–1.20; p < 0.05 were associated with elevated mPAP and were defined as a cut-off. Interestingly, the correspondence analysis identified association patterns of several other variables (metabolic, labor, and biomedical with higher mPAP.Conclusions: Working intermittently at high altitude involves a distinctive pattern. The most relevant and

  3. Upward Shift and Steepening of the Blood Pressure Response to Exercise in Hypertensive Subjects at High Altitude.

    Science.gov (United States)

    Caravita, Sergio; Faini, Andrea; Baratto, Claudia; Bilo, Grzegorz; Macarlupu, Josè Luis; Lang, Morin; Revera, Miriam; Lombardi, Carolina; Villafuerte, Francisco C; Agostoni, Piergiuseppe; Parati, Gianfranco

    2018-06-09

    Acute exposure to high-altitude hypobaric hypoxia induces a blood pressure rise in hypertensive humans, both at rest and during exercise. It is unclear whether this phenomenon reflects specific blood pressure hyperreactivity or rather an upward shift of blood pressure levels. We aimed at evaluating the extent and rate of blood pressure rise during exercise in hypertensive subjects acutely exposed to high altitude, and how these alterations can be counterbalanced by antihypertensive treatment. Fifty-five subjects with mild hypertension, double-blindly randomized to placebo or to a fixed-dose combination of an angiotensin-receptor blocker (telmisartan 80 mg) and a calcium-channel blocker (nifedipine slow release 30 mg), performed a cardiopulmonary exercise test at sea level and after the first night's stay at 3260 m altitude. High-altitude exposure caused both an 8 mm Hg upward shift ( P blood pressure/oxygen consumption relationship during exercise, independent of treatment. Telmisartan/nifedipine did not modify blood pressure reactivity to exercise (blood pressure/oxygen consumption slope), but downward shifted ( P blood pressure and oxygen consumption by 26 mm Hg, both at sea level and at altitude. Muscle oxygen delivery was not influenced by altitude exposure but was higher on telmisartan/nifedipine than on placebo ( P blood pressure response to exercise. The effect of the combination of telmisartan/nifedipine slow release outweighed these changes and was associated with better muscle oxygen delivery. URL: http://www.clinicaltrials.gov. Unique identifier: NCT01830530. © 2018 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

  4. Angiotensin-converting enzyme (ACE) alleles in the Quechua, a high altitude South American native population.

    Science.gov (United States)

    Rupert, J L; Devine, D V; Monsalve, M V; Hochachka, P W

    1999-01-01

    Recently it was reported that an allelic variant of the gene encoding angiotensin-converting enzyme (ACE) was significantly over-represented in a cohort of elite British mountaineers. It was proposed that this may be evidence for a specific genetic factor influencing the human capacity for physical performance. The implication that this allele could enhance performance at high altitude prompted us to determine its frequency in Quechua speaking natives living at altitudes greater than 3000m on the Andean Altiplano in South America. We found that the frequency of the putative performance allele in the Quechuas, although significantly higher than in Caucasians, was not different from lowland Native American populations. This observation suggests that, although the higher frequency of the 'performance allele' may have facilitated the migration of the ancestral Quechua to the highlands, the ACE insertion allele has not been subsequently selected for in this high altitude population.

  5. Anthropometric survey of high-altitude Bolivian porters.

    Science.gov (United States)

    Leatherman, T L; Thomas, R B; Greksa, L P; Haas, J D

    1984-01-01

    This paper presents the results of an anthropometric survey of 138 rural Aymaran high-altitude males who were working as porters in La Paz, Bolivia (3700 m). All subjects were measured for stature, weight, upper arm circumference, and triceps skinfolds. The body size and composition of the porters were then compared to an Aymaran rural population from the Bolivian highlands, and urban mestizo labourers from La Paz. The porters were smaller than the urban sample, but appeared to be generally representative of rural Aymaran natives with respect to body size and composition, and nutritional status. It is suggested that towards one extreme of nutritional variability, some degree of undernutrition may be indicated, which should be considered in future studies of adaptation to hypoxia among these Andean highlanders.

  6. The use of high altitude remote sensing in determining existing vegetation and monitoring ecological stress

    Science.gov (United States)

    Foster, K.; Garcia, A.

    1972-01-01

    High altitude color and multispectral black and white photography was used to survey existing vegetation and soil conditions on the Empire Ranch where large scale development will soon begin. Utilizing stereo pairs of the high altitude color photography, four vegetation classifications were discernable as a function of topography and foliage characteristics. In contrast to the undeveloped Ranch, the same photography was used to detect environmental changes in the Tucson metropolitan area as a result of rapid urbanization. The most prevalent change related to development is the removal of vegetation in high density areas to allow for housing starts. Erosion then occurs where vegetation has been removed.

  7. Model simulations with COSMO-SPECS: impact of heterogeneous freezing modes and ice nucleating particle types on ice formation and precipitation in a deep convective cloud

    Directory of Open Access Journals (Sweden)

    K. Diehl

    2018-03-01

    Full Text Available In deep convective clouds, heavy rain is often formed involving the ice phase. Simulations were performed using the 3-D cloud resolving model COSMO-SPECS with detailed spectral microphysics including parameterizations of homogeneous and three heterogeneous freezing modes. The initial conditions were selected to result in a deep convective cloud reaching 14 km of altitude with strong updrafts up to 40 m s−1. At such altitudes with corresponding temperatures below −40 °C the major fraction of liquid drops freezes homogeneously. The goal of the present model simulations was to investigate how additional heterogeneous freezing will affect ice formation and precipitation although its contribution to total ice formation may be rather low. In such a situation small perturbations that do not show significant effects at first sight may trigger cloud microphysical responses. Effects of the following small perturbations were studied: (1 additional ice formation via immersion, contact, and deposition modes in comparison to solely homogeneous freezing, (2 contact and deposition freezing in comparison to immersion freezing, and (3 small fractions of biological ice nucleating particles (INPs in comparison to higher fractions of mineral dust INP. The results indicate that the modification of precipitation proceeds via the formation of larger ice particles, which may be supported by direct freezing of larger drops, the growth of pristine ice particles by riming, and by nucleation of larger drops by collisions with pristine ice particles. In comparison to the reference case with homogeneous freezing only, such small perturbations due to additional heterogeneous freezing rather affect the total precipitation amount. It is more likely that the temporal development and the local distribution of precipitation are affected by such perturbations. This results in a gradual increase in precipitation at early cloud stages instead of a strong increase at

  8. Hydrological processes in glacierized high-altitude basins of the western Himalayas

    Science.gov (United States)

    Jeelani, Ghulam; Shah, Rouf A.; Fryar, Alan E.; Deshpande, Rajendrakumar D.; Mukherjee, Abhijit; Perrin, Jerome

    2018-03-01

    Western Himalaya is a strategically important region, where the water resources are shared by China, India and Pakistan. The economy of the region is largely dependent on the water resources delivered by snow and glacier melt. The presented study used stable isotopes of water to further understand the basin-scale hydro-meteorological, hydrological and recharge processes in three high-altitude mountainous basins of the western Himalayas. The study provided new insights in understanding the dominant factors affecting the isotopic composition of the precipitation, snowpack, glacier melt, streams and springs. It was observed that elevation-dependent post-depositional processes and snowpack evolution resulted in the higher isotopic altitude gradient in snowpacks. The similar temporal trends of isotopic signals in rivers and karst springs reflect the rapid flow transfer due to karstification of the carbonate aquifers. The attenuation of the extreme isotopic input signal in karst springs appears to be due to the mixing of source waters with the underground karst reservoirs. Basin-wise, the input-output response demonstrates the vital role of winter precipitation in maintaining the perennial flow in streams and karst springs in the region. Isotopic data were also used to estimate the mean recharge altitude of the springs.

  9. Comparing elevation and freeboard from IceBridge and four different CryoSat-2 retrackers for coincident sea ice observations

    Science.gov (United States)

    Yi, D.; Kurtz, N. T.; Harbeck, J.

    2017-12-01

    The airborne IceBridge and spaceborne Cryosat-2 missions observe polar sea ice at different altitudes with different footprint sizes and often at different time and locations. Many studies use different retrackers to derive Cryosat-2 surface elevation, which we find causes large differences in the elevation and freeboard comparisons of IceBridge and Cryosat-2. In this study, we compare sea ice surface elevation and freeboard using 8 coincident CryoSat-2, ATM, and LVIS observations with IceBridge airplanes under flying the Cryosat-2 ground tracks. We apply identical ellipsoid, geoid model, tide model, and atmospheric correction to CryoSat-2 and IceBridge data to reduce elevation bias due to their differences. IceBridge's ATM and LVIS elevation and freeboard and Snow Radar snow depth are averaged at each CryoSat-2 footprint for comparison. The four different Cryosat-2 retrackers (ESA, GSFC, AWI, and JPL) show distinct differences in mean elevation up to 0.35 meters over leads and over floes, which suggests that systematic elevation bias exists between the retrackers. The mean IceBridge elevation over leads is within the mean elevation distribution of the four Cryosat-2 retrackers. The mean IceBridge elevation over floes is above the mean elevation distribution of the four Cryosat-2 retrackers. After removing the snow depth from IceBridge elevation, over floe, the mean elevation of IceBridge is within the mean elevation distribution of the four Cryosat-2 retrackers. By identifying the strengths and weaknesses of the retrackers, this study provides a mechanism to improve freeboard retrievals from existing methods.

  10. High-resolution altitude profiles of the atmospheric turbulence with PML at the Sutherland Observatory

    Science.gov (United States)

    Catala, L.; Ziad, A.; Fanteï-Caujolle, Y.; Crawford, S. M.; Buckley, D. A. H.; Borgnino, J.; Blary, F.; Nickola, M.; Pickering, T.

    2017-05-01

    With the prospect of the next generation of ground-based telescopes, the extremely large telescopes, increasingly complex and demanding adaptive optics systems are needed. This is to compensate for image distortion caused by atmospheric turbulence and fully take advantage of mirrors with diameters of 30-40 m. This requires a more precise characterization of the turbulence. The Profiler of Moon Limb (PML) was developed within this context. The PML aims to provide high-resolution altitude profiles of the turbulence using differential measurements of the Moon limb position to calculate the transverse spatio-angular covariance of the angle of arrival fluctuations. The covariance of differential image motion for different separation angles is sensitive to the altitude distribution of the seeing. The use of the continuous Moon limb provides a large number of separation angles allowing for the high-resolution altitude of the profiles. The method is presented and tested with simulated data. Moreover, a PML instrument was deployed at the Sutherland Observatory in South Africa in 2011 August. We present here the results of this measurement campaign.

  11. Effect of high altitude cosmic irradiation upon cell generation time

    International Nuclear Information System (INIS)

    Soleilhavoup, J.P.; Croute, F.; Tixador, R.; Blanquet, Y.; Planel, H.

    1975-01-01

    Paramecia cultures placed at 3800 meter altitude show a proliferating activity acceleration compared to control cultures placed at low altitude under the same environment conditions. These results confirm the cosmic irradiation influence upon the activating effect produced by the natural ionizing radiations on living organisms [fr

  12. High Altitude Venus Operations Concept Trajectory Design, Modeling and Simulation

    Science.gov (United States)

    Lugo, Rafael A.; Ozoroski, Thomas A.; Van Norman, John W.; Arney, Dale C.; Dec, John A.; Jones, Christopher A.; Zumwalt, Carlie H.

    2015-01-01

    A trajectory design and analysis that describes aerocapture, entry, descent, and inflation of manned and unmanned High Altitude Venus Operation Concept (HAVOC) lighter-than-air missions is presented. Mission motivation, concept of operations, and notional entry vehicle designs are presented. The initial trajectory design space is analyzed and discussed before investigating specific trajectories that are deemed representative of a feasible Venus mission. Under the project assumptions, while the high-mass crewed mission will require further research into aerodynamic decelerator technology, it was determined that the unmanned robotic mission is feasible using current technology.

  13. Interactions of carbon monoxide and hemoglobin at high altitude

    Energy Technology Data Exchange (ETDEWEB)

    Collier, C.R. (Univ. of Southern California Medical Center, Los Angeles); Goldsmith, J.R.

    1983-01-01

    The health risks to U.S. populations who are exposed to ambient carbon monoxide and live at altitudes (such as Denver, Salt Lake City, and Albuquerque) were evaluated using a set of mathematical models. The assumption that a given increase in carboxyhemoglobin would require a more stringent volumetric air quality standard was tested. The results using the model predict that the 8-h or 1-h standards adopted for sea level condition need not be altered to protect individuals against health risks at altitude, if the standards are in volumetric terms. They would need to be reduced if the standards are left in gravimetric terms. If the guideline is to be based on a given decrement of oxygen tension, many other variables must be specified, but expected differences in ambient carbon monoxide have a small impact compared to the effect of altitude itself.

  14. Performance simulation in high altitude platforms (HAPs) communications systems

    Science.gov (United States)

    Ulloa-Vásquez, Fernando; Delgado-Penin, J. A.

    2002-07-01

    This paper considers the analysis by simulation of a digital narrowband communication system for an scenario which consists of a High-Altitude aeronautical Platform (HAP) and fixed/mobile terrestrial transceivers. The aeronautical channel is modelled considering geometrical (angle of elevation vs. horizontal distance of the terrestrial reflectors) and statistical arguments and under these circumstances a serial concatenated coded digital transmission is analysed for several hypothesis related to radio-electric coverage areas. The results indicate a good feasibility for the communication system proposed and analysed.

  15. High-altitude wind resources in the Middle East

    KAUST Repository

    Yip, Chak Man Andrew; Gunturu, Udaya; Stenchikov, Georgiy L.

    2017-01-01

    In the Middle East, near-surface wind resources are intermittent. However, high-altitude wind resources are abundant, persistent, and readily available and may provide alternative energy resources in this fossil-fuel-dependent region. Using wind field data from the Modern-Era Retrospective Analysis for Research and Applications Version 2 (MERRA-2), this study identifies areas favorable to the deployment of airborne wind energy (AWE) systems in the Middle East and computes the optimal heights at which such systems would best operate. AWE potential is estimated using realistic AWE system specifications and assumptions about deployment scenarios and is compared with the near-surface wind generation potential with respect to diurnal and seasonal variability. The results show the potential utility of AWE in areas in the Middle East where the energy demand is high. In particular, Oman and Saudi Arabia have a high level of the potential power generation with low annual variability.

  16. High-altitude wind resources in the Middle East

    KAUST Repository

    Yip, Chak Man Andrew

    2017-08-23

    In the Middle East, near-surface wind resources are intermittent. However, high-altitude wind resources are abundant, persistent, and readily available and may provide alternative energy resources in this fossil-fuel-dependent region. Using wind field data from the Modern-Era Retrospective Analysis for Research and Applications Version 2 (MERRA-2), this study identifies areas favorable to the deployment of airborne wind energy (AWE) systems in the Middle East and computes the optimal heights at which such systems would best operate. AWE potential is estimated using realistic AWE system specifications and assumptions about deployment scenarios and is compared with the near-surface wind generation potential with respect to diurnal and seasonal variability. The results show the potential utility of AWE in areas in the Middle East where the energy demand is high. In particular, Oman and Saudi Arabia have a high level of the potential power generation with low annual variability.

  17. Genetic variants in EPAS1 contribute to adaptation to high-altitude hypoxia in Sherpas.

    Directory of Open Access Journals (Sweden)

    Masayuki Hanaoka

    Full Text Available Sherpas comprise a population of Tibetan ancestry in the Himalayan region that is renowned for its mountaineering prowess. The very small amount of available genetic information for Sherpas is insufficient to explain their physiological ability to adapt to high-altitude hypoxia. Recent genetic evidence has indicated that natural selection on the endothelial PAS domain protein 1 (EPAS1 gene was occurred in the Tibetan population during their occupation in the Tibetan Plateau for millennia. Tibetan-specific variations in EPAS1 may regulate the physiological responses to high-altitude hypoxia via a hypoxia-inducible transcription factor pathway. We examined three significant tag single-nucleotide polymorphisms (SNPs, rs13419896, rs4953354, and rs4953388 in the EPAS1 gene in Sherpas, and compared these variants with Tibetan highlanders on the Tibetan Plateau as well as with non-Sherpa lowlanders. We found that Sherpas and Tibetans on the Tibetan Plateau exhibit similar patterns in three EPAS1 significant tag SNPs, but these patterns are the reverse of those in non-Sherpa lowlanders. The three SNPs were in strong linkage in Sherpas, but in weak linkage in non-Sherpas. Importantly, the haplotype structured by the Sherpa-dominant alleles was present in Sherpas but rarely present in non-Sherpas. Surprisingly, the average level of serum erythropoietin in Sherpas at 3440 m was equal to that in non-Sherpas at 1300 m, indicating a resistant response of erythropoietin to high-altitude hypoxia in Sherpas. These observations strongly suggest that EPAS1 is under selection for adaptation to the high-altitude life of Tibetan populations, including Sherpas. Understanding of the mechanism of hypoxia tolerance in Tibetans is expected to provide lights to the therapeutic solutions of some hypoxia-related human diseases, such as cardiovascular disease and cancer.

  18. Latitudinal and interhemispheric variation of stratospheric effects on mesospheric ice layer trends

    Science.gov (United States)

    Lübken, F.-J.; Berger, U.

    2011-02-01

    Latitudinal and interhemispheric differences of model results on trends in mesospheric ice layers and background conditions are analyzed. The model nudges to European Centre for Medium-Range Weather Forecasts data below ˜45 km. Greenhouse gas concentrations in the mesosphere are kept constant. Temperature trends in the mesosphere mainly come from shrinking of the stratosphere and from dynamical effects. Water vapor increases at noctilucent cloud (NLC) heights and decreases above due to increased freeze drying caused by temperature trends. There is no tendency for ice clouds in the Northern Hemisphere for extending farther southward with time. Trends of NLC albedo are similar to satellite measurements, but only if a time period longer than observations is considered. Ice cloud trends get smaller if albedo thresholds relevant to satellite instruments are applied, in particular at high polar latitudes. This implies that weak and moderate NLC is favored when background conditions improve for NLC formation, whereas strong NLC benefits less. Trends of ice cloud parameters are generally smaller in the Southern Hemisphere (SH) compared to the Northern Hemisphere (NH), consistent with observations. Trends in background conditions have counteracting effects on NLC: temperature trends would suggest stronger ice increase in the SH, and water vapor trends would suggest a weaker increase. Larger trends in NLC brightness or occurrence rates are not necessarily associated with larger (more negative) temperature trends. They can also be caused by larger trends of water vapor caused by larger freeze drying, which in turn can be caused by generally lower temperatures and/or more background water. Trends of NLC brightness and occurrence rates decrease with decreasing latitude in both hemispheres. The latitudinal variation of these trends is primarily determined by induced water vapor trends. Trends in NLC altitudes are generally small. Stratospheric temperature trends vary

  19. Moessbauer studies of hemoglobin in high altitude polycythemia

    International Nuclear Information System (INIS)

    Zhang Xiufang; Shen Linming; Chen Songsen; Ao Zhaohui; Liu Yuanyuan; Gao Naifei; Zheng Yuanming; Shong Liangquan

    1990-01-01

    The Moessbauer spectra have been measured in erythrocytes from normal adults and the patients with high altitude polycythemia (HAPC). The results indicated that two subspectra ''a'' and ''b'', corresponding to oxy- and deoxyhemoglobin respectively, were present in all blood samples, and a third subspectrum ''c'' was found to exist in almost all samples from the patients. The parameters of the third subspectra ''c1'' in most samples from the patients were similar to those of carbon monoxyhemoglobin. The components were considered to be the denatured hemoglobin in RBCs (red blood cells). Together with clinical analysis, a possible mechanism of HAPC has been discussed. (orig.)

  20. Inland and Near Shore Water Profiles Derived from the High Altitude Multiple Altimeter Beam Experimental Lidar (MABEL)

    Science.gov (United States)

    Jasinski, Michael F.; Stoll, Jeremy D.; Cook, William B.; Ondrusek, Michael; Stengel, Eric; Brunt, Kelly

    2016-01-01

    The Advanced Topographic Laser Altimeter System (ATLAS) on the Ice, Cloud, and Land Elevation Satellite (ICESat-2) mission is a six beam, low energy, high repetition rate, 532 nm laser transmitter with photon counting detectors. Although designed primarily for detecting height changes in icecaps, sea ice and vegetation, the polar-orbital satellite will observe global surface water during its designed three year life span, including inland water bodies, coasts, and open oceans. In preparation for the mission, an ICESat-2 prototype or the Multiple Altimeter Beam Experimental Lidar (MABEL), was built and flown on high altitude aircraft experiments over a range of inland and near-shore targets. The purpose was to test the ATLAS concept and to provide a database for developing an algorithm that detects along track surface water height and light penetration under a range of atmospheric and water conditions. The current analysis examines the datasets of three MABEL transects observed from 20 km above ground of coastal and inland waters conducted in 2012 and 2013. Transects ranged from about 2 to 12 km in length and included the middle Chesapeake Bay, the near shore Atlantic coast at Virginia Beach, and Lake Mead. Results indicate MABEL's high capability for retrieving surface water height statistics with a mean height precision of approximately 5-7 cm per 100m segment length. Profiles of attenuated subsurface backscatter, characterized using a Signal to Background Ratio written in Log10 base, or LSBR0, were observed over a range of 1.3 to 9.3 meters depending on water clarity and atmospheric background. Results indicate that observable penetration depth, although primarily dependent on water properties, was greatest when solar background rate was low. Near shore bottom reflectance was detected only at the Lake Mead site down to maximum of 10 m under a clear night sky and low turbidity of approximately 1.6 Nephelometric Turbidity Units (NTU). The overall results suggest

  1. New Heights with High-Altitude Balloon Launches for Effective Student Learning and Environmental Awareness

    Science.gov (United States)

    Voss, H. D.; Dailey, J. F.; Takehara, D.; Krueger, J. M.

    2009-12-01

    Over a seven-year period Taylor University, an undergraduate liberal art school, has successfully launched and recovered over 200 sophisticated student payloads to altitudes between 20-33 km (100% success with rapid recovery) with flight times between 2 to 6 hrs. All of the payloads included two GPS tracking systems, cameras and monitors, a 110 kbit down link, an uplink command capability for educational experiments (K-12 and undergrad). Launches were conducted during the day and night, with multiple balloons, with up to 10 payloads for experiments, and under varying weather and upper atmospheric conditions. The many launches in a short period of time allowed the payload bus design to evolve toward increased performance, reliability, standardization, simplicity, and modularity for low-cost launch services. Through NSF and NASA grants, the program has expanded leading to over 50 universities trained at workshops to implement high altitude balloon launches in the classroom. A spin-off company (StraoStar Systems LLC) now sells the high-altitude balloon system and facilitates networking between schools. This high-altitude balloon program helps to advance knowledge and understanding across disciplines by giving students and faculty rapid and low-cost access to earth/ecology remote sensing from high altitude, insitu and limb atmospheric measurements, near-space stratosphere measurements, and IR/UV/cosmic ray access to the heavens. This new capability is possible by exposing students to recent advances in MEMS technology, nanotechnology, wireless telecommunication systems, GPS, DSPs and other microchip miniaturizations to build collaboration among science faculty, and provides quantitative assessment of the learning outcomes. Furthermore this program has generated many front page news reports along with significant TV coverage because of its connection to hands-on learning for students and adults of all ages, connection to understanding climate change and ways to mitigate

  2. The effect of α1 -adrenergic blockade on post-exercise brachial artery flow-mediated dilatation at sea level and high altitude.

    Science.gov (United States)

    Tymko, Michael M; Tremblay, Joshua C; Hansen, Alex B; Howe, Connor A; Willie, Chris K; Stembridge, Mike; Green, Daniel J; Hoiland, Ryan L; Subedi, Prajan; Anholm, James D; Ainslie, Philip N

    2017-03-01

    Our objective was to quantify endothelial function (via brachial artery flow-mediated dilatation) at sea level (344 m) and high altitude (3800 m) at rest and following both maximal exercise and 30 min of moderate-intensity cycling exercise with and without administration of an α 1 -adrenergic blockade. Brachial endothelial function did not differ between sea level and high altitude at rest, nor following maximal exercise. At sea level, endothelial function decreased following 30 min of moderate-intensity exercise, and this decrease was abolished with α 1 -adrenergic blockade. At high altitude, endothelial function did not decrease immediately after 30 min of moderate-intensity exercise, and administration of α 1 -adrenergic blockade resulted in an increase in flow-mediated dilatation. Our data indicate that post-exercise endothelial function is modified at high altitude (i.e. prolonged hypoxaemia). The current study helps to elucidate the physiological mechanisms associated with high-altitude acclimatization, and provides insight into the relationship between sympathetic nervous activity and vascular endothelial function. We examined the hypotheses that (1) at rest, endothelial function would be impaired at high altitude compared to sea level, (2) endothelial function would be reduced to a greater extent at sea level compared to high altitude after maximal exercise, and (3) reductions in endothelial function following moderate-intensity exercise at both sea level and high altitude are mediated via an α 1 -adrenergic pathway. In a double-blinded, counterbalanced, randomized and placebo-controlled design, nine healthy participants performed a maximal-exercise test, and two 30 min sessions of semi-recumbent cycling exercise at 50% peak output following either placebo or α 1 -adrenergic blockade (prazosin; 0.05 mg kg  -1 ). These experiments were completed at both sea-level (344 m) and high altitude (3800 m). Blood pressure (finger photoplethysmography

  3. Polarimetric signatures of sea ice in the Greenland Sea

    DEFF Research Database (Denmark)

    Skriver, Henning; Pedersen, Leif Toudal

    1995-01-01

    Polarimetric SAR data of sea ice have been acquired by the Danish polarimetric SAR (EMISAR) during a mission at the Greenland Sea in August 1994. Video recordings from a low-altitude acquisition have been used for interpretation of the SAR data. Also, ERS-1 SAR data and NOAA AVHRR-data have been...

  4. In situ measurements of tropical cloud properties in the West African Monsoon: upper tropospheric ice clouds, Mesoscale Convective System outflow, and subvisual cirrus

    Directory of Open Access Journals (Sweden)

    W. Frey

    2011-06-01

    Full Text Available In situ measurements of ice crystal size distributions in tropical upper troposphere/lower stratosphere (UT/LS clouds were performed during the SCOUT-AMMA campaign over West Africa in August 2006. The cloud properties were measured with a Forward Scattering Spectrometer Probe (FSSP-100 and a Cloud Imaging Probe (CIP operated aboard the Russian high altitude research aircraft M-55 Geophysica with the mission base in Ouagadougou, Burkina Faso. A total of 117 ice particle size distributions were obtained from the measurements in the vicinity of Mesoscale Convective Systems (MCS. Two to four modal lognormal size distributions were fitted to the average size distributions for different potential temperature bins. The measurements showed proportionately more large ice particles compared to former measurements above maritime regions. With the help of trace gas measurements of NO, NOy, CO2, CO, and O3 and satellite images, clouds in young and aged MCS outflow were identified. These events were observed at altitudes of 11.0 km to 14.2 km corresponding to potential temperature levels of 346 K to 356 K. In a young outflow from a developing MCS ice crystal number concentrations of up to (8.3 ± 1.6 cm−3 and rimed ice particles with maximum dimensions exceeding 1.5 mm were found. A maximum ice water content of 0.05 g m−3 was observed and an effective radius of about 90 μm. In contrast the aged outflow events were more diluted and showed a maximum number concentration of 0.03 cm−3, an ice water content of 2.3 × 10−4 g m−3, an effective radius of about 18 μm, while the largest particles had a maximum dimension of 61 μm.

    Close to the tropopause subvisual cirrus were encountered four times at altitudes of 15 km to 16.4 km. The mean ice particle number concentration of these encounters was 0.01 cm−3 with maximum particle sizes of 130

  5. Correlations between the simulated military tasks performance and physical fitness tests at high altitude

    Directory of Open Access Journals (Sweden)

    Eduardo Borba Neves

    2017-11-01

    Full Text Available The aim of this study was to investigate the Correlations between the Simulated Military Tasks Performance and Physical Fitness Tests at high altitude. This research is part of a project to modernize the physical fitness test of the Colombian Army. Data collection was performed at the 13th Battalion of Instruction and Training, located 30km south of Bogota D.C., with a temperature range from 1ºC to 23ºC during the study period, and at 3100m above sea level. The sample was composed by 60 volunteers from three different platoons. The volunteers start the data collection protocol after 2 weeks of acclimation at this altitude. The main results were the identification of a high positive correlation between the 3 Assault wall in succession and the Simulated Military Tasks performance (r = 0.764, p<0.001, and a moderate negative correlation between pull-ups and the Simulated Military Tasks performance (r = -0.535, p<0.001. It can be recommended the use of the 20-consecutive overtaking of the 3 Assault wall in succession as a good way to estimate the performance in operational tasks which involve: assault walls, network of wires, military Climbing Nets, Tarzan jump among others, at high altitude.

  6. Station-keeping of a high-altitude balloon with electric propulsion and wireless power transmission: A concept study

    Science.gov (United States)

    van Wynsberghe, Erinn; Turak, Ayse

    2016-11-01

    A stable, ultra long-duration high-altitude balloon (HAB) platform which can maintain stationary position would represent a new paradigm for telecommunications and high-altitude observation and transmission services, with greatly reduced cost and complexity compared to existing technologies including satellites, telecom towers, and unmanned aerial vehicles (UAVs). This contribution proposes a lightweight superpressure balloon platform for deployment to an altitude of 25 km. Electrohydrodynamic (EHD) thrusters are presented to maintain position by overcoming stratospheric winds. Critical to maintaining position is a continual supply of electrical power to operate the on-board propulsion system. One viable solution is to deliver power wirelessly to a high-altitude craft from a ground-based transmitter. Microwave energy, not heavily attenuated by the atmosphere, can be provided remotely from a ground-based generator (magnetron, klystron, etc.) and steered electrically with an antenna array (phased array) at a designated frequency (such as 2.45 or 5.8 GHz). A rectifying antenna ("rectenna") on the bottom of the balloon converts waves into direct current for on-board use. Preliminary mission architecture, energy requirements, and safety concerns for a proposed system are presented along with recommended future work.

  7. Assessment of the High Resolution SAR Mode of the RADARSAT Constellation Mission for First Year Ice and Multiyear Ice Characterization

    Directory of Open Access Journals (Sweden)

    Mohammed Dabboor

    2018-04-01

    Full Text Available Simulated compact polarimetry from the RADARSAT Constellation Mission (RCM is evaluated for sea ice classification. Compared to previous studies that evaluated the potential of RCM for sea ice classification, this study focuses on the High Resolution (HR Synthetic Aperture Radar (SAR mode of the RCM associated with a higher noise floor (Noise Equivalent Sigma Zero of −19 dB, which can prove challenging for sea ice monitoring. Twenty three Compact Polarimetric (CP parameters were derived and analyzed for the discrimination between first year ice (FYI and multiyear ice (MYI. The results of the RCM HR mode are compared with those previously obtained for other RCM SAR modes for possible CP consistency parameters in sea ice classification under different noise floors, spatial resolutions, and radar incidence angles. Finally, effective CP parameters were identified and used for the classification of FYI and MYI using the Random Forest (RF classification algorithm. This study indicates that, despite the expected high noise floor of the RCM HR mode, CP SAR data from this mode are promising for the classification of FYI and MYI in dry ice winter conditions. The overall classification accuracies of CP SAR data over two test sites (96.13% and 96.84% were found to be comparable to the accuracies obtained using Full Polarimetric (FP SAR data (98.99% and 99.20%.

  8. Recent ice cap snowmelt in Russian High Arctic and anti-correlation with late summer sea ice extent

    International Nuclear Information System (INIS)

    Zhao, Meng; Ramage, Joan; Semmens, Kathryn; Obleitner, Friedrich

    2014-01-01

    Glacier surface melt dynamics throughout Novaya Zemlya (NovZ) and Severnaya Zemlya (SevZ) serve as a good indicator of ice mass ablation and regional climate change in the Russian High Arctic. Here we report trends of surface melt onset date (MOD) and total melt days (TMD) by combining multiple resolution-enhanced active and passive microwave satellite datasets and analyze the TMD correlations with local temperature and regional sea ice extent. The glacier surface snowpack on SevZ melted significantly earlier (−7.3 days/decade) from 1992 to 2012 and significantly longer (7.7 days/decade) from 1995 to 2011. NovZ experienced large interannual variability in MOD, but its annual mean TMD increased. The snowpack melt on NovZ is more sensitive to temperature fluctuations than SevZ in recent decades. After ruling out the regional temperature influence using partial correlation analysis, the TMD on both archipelagoes is statistically anti-correlated with regional late summer sea ice extent, linking land ice snowmelt dynamics to regional sea ice extent variations. (letter)

  9. High-altitude electromagnetic pulse environment over the lossy ground

    International Nuclear Information System (INIS)

    Xie Yanzhao; Wang Zanji

    2003-01-01

    The electromagnetic field above ground produced by an incident high-altitude electromagnetic pulse plane wave striking the ground plane was described in this paper in terms of the Fresnel reflection coefficients and the numerical FFT. The pulse reflected from the ground plane always cancel the incident field for the horizontal field component, but the reflected field adds to the incident for the vertical field component. The results of several cases for variations in the observation height, angle of incidence and lossy ground electrical parameters were also presented showing different e-field components above the earth

  10. In situ neutron diffraction studies of high density amorphous ice under pressure

    International Nuclear Information System (INIS)

    Klotz, Stefan; Straessle, Th; Saitta, A M; Rousse, G; Hamel, G; Nelmes, R J; Loveday, J S; Guthrie, M

    2005-01-01

    We review recent in situ neutron diffraction studies on the structural pressure dependence and the recrystallization of dense amorphous ices up to 2 GPa. Progress in high pressure techniques and data analysis methods allows the reliable determination of all three partial structure factors of amorphous ice under pressure. The strong pressure dependence of the g OO (r) correlation function shows that the isothermal compression of high density amorphous ice (HDA) at 100 K is achieved by a contraction (∼ 20%) of the second-neighbour coordination shell leading to a strong increase in coordination. The g DD (r) and g OD (r) structure factors are, in contrast, only weakly sensitive to pressure. These data allow a comparison with structural features of the recently reported 'very high density amorphous ice' (VHDA) which indicates that VHDA at ambient pressure is very similar to compressed HDA, at least up to the second-neighbour shell. The recrystallization of HDA has been investigated in the range 0.3-2 GPa. It is shown that hydrogen-disordered phases are produced which normally grow only from the liquid, such as ice XII, and in particular ice IV. These findings are in good agreement with results on quench-recovered samples

  11. Effects of high altitude training on exercise capacity: fact or myth.

    Science.gov (United States)

    de Paula, Paula; Niebauer, Josef

    2012-03-01

    High altitude training has become a mainstay in endurance sports, with live high-train low as the current protocol of choice. Athletes either live or sleep in artificial or natural hypoxic conditions with the aim to increase serum erythropoietin concentrations, which are thought to improve maximum oxygen uptake and thus exercise performance. Changes, however, are not very striking and only apparent in so-called responders, who are not a well-defined group and may be as little as 50% of the trained study population. Whereas some studies show minor improvement, others report no change or even worsening. Furthermore, the mechanisms behind the proposed beneficial changes remain obscure and are far from being proven. There is an evident lack of sufficiently powered randomized, double-blinded studies, with training protocols that are identical for all groups and groups that are indeed comparable. Several studies discriminate between responders and non-responders, without clearly assessing the characteristics of the so-called responders. Until this has been done, it remains unclear if such a group really exists and how these subjects are characterized. This, however, would be of immense value, so protocols could be tailored to athletes' needs. Taken together, the current literature on natural or artificial hypoxia somewhat documents improved performance at high but not low altitude.

  12. Ferroelectricity in high-density H{sub 2}O ice

    Energy Technology Data Exchange (ETDEWEB)

    Caracas, Razvan, E-mail: razvan.caracas@ens-lyon.fr, E-mail: rhemley@ciw.edu [CNRS, Laboratoire de Géologie de Lyon UMR5276, Ecole Normale Supérieure de Lyon, 46, alleé d’Italie, Université Claude-Bernard Lyon 1, Université de Lyon, 69364 Lyon cedex 07 (France); Hemley, Russell J., E-mail: razvan.caracas@ens-lyon.fr, E-mail: rhemley@ciw.edu [Geophysical Laboratory, 5251 Broad Branch Road NW, Carnegie Institution of Washington, Washington, DC 20015 (United States)

    2015-04-07

    The origin of longstanding anomalies in experimental studies of the dense solid phases of H{sub 2}O ices VII, VIII, and X is examined using a combination of first-principles theoretical methods. We find that a ferroelectric variant of ice VIII is energetically competitive with the established antiferroelectric form under pressure. The existence of domains of the ferroelectric form within anti-ferroelectric ice can explain previously observed splittings in x-ray diffraction data. The ferroelectric form is stabilized by density and is accompanied by the onset of spontaneous polarization. The presence of local electric fields triggers the preferential parallel orientation of the water molecules in the structure, which could be stabilized in bulk using new high-pressure techniques.

  13. Application of altitude/hypoxic training by elite athletes.

    Science.gov (United States)

    Wilber, Randall L

    2007-09-01

    At the Olympic level, differences in performance are typically less than 0.5%. This helps explain why many contemporary elite endurance athletes in summer and winter sport incorporate some form of altitude/hypoxic training within their year-round training plan, believing that it will provide the "competitive edge" to succeed at the Olympic level. The purpose of this paper is to describe the practical application of altitude/hypoxic training as used by elite athletes. Within the general framework of the paper, both anecdotal and scientific evidence will be presented relative to the efficacy of several contemporary altitude/hypoxic training models and devices currently used by Olympic-level athletes for the purpose of legally enhancing performance. These include the three primary altitude/hypoxic training models: 1) live high+train high (LH+TH), 2) live high+train low (LH+TL), and 3) live low+train high (LL+TH). The LH+TL model will be examined in detail and will include its various modifications: natural/terrestrial altitude, simulated altitude via nitrogen dilution or oxygen filtration, and hypobaric normoxia via supplemental oxygen. A somewhat opposite approach to LH+TL is the altitude/hypoxic training strategy of LL+TH, and data regarding its efficacy will be presented. Recently, several of these altitude/hypoxic training strategies and devices underwent critical review by the World Anti-Doping Agency (WADA) for the purpose of potentially banning them as illegal performance-enhancing substances/methods. This paper will conclude with an update on the most recent statement from WADA regarding the use of simulated altitude devices.

  14. Development of a Compact High Altitude Imager and Sounding Radiometer (CHAISR)

    Science.gov (United States)

    Choi, R. K. Y.; Min, S.; Cho, Y. J.; Kim, K. H.; Ha, J. C.; Joo, S. W.

    2017-12-01

    Joint Civilian-Military Committee, under Advisory Council on Science and Technology, Korea, has approved a technology demonstration project for developing a lightweight HALE UAV (High-Altitude, Long Endurance). It aims to operate at lower stratosphere, i.e. altitude of 16 20 km, offering unique observational platform to atmospheric research community as pseudo-satellite. NIMS (National Institute of Meteorological Sciences, Korea) is responsible for a payload for atmospheric science, a Compact High Altitude Imager and Sounding Radiometer (CHAISR) to demonstrate scientific observations at lower stratosphere in the interest of improving numerical weather prediction model. CHAISR consists of three microwave radiometers (MWR) with 16 channel, and medium resolution cameras operating in a visible and infrared spectrum. One of the technological challenges for CHAISR is to accommodate those instruments within 50 W of power consumption. CHAISR will experience temperature up to -75°C, while pressure as low as 50 hPa at operational altitude. It requires passive thermal control of the payload to keep electronic subsystems warm enough for instrument operation with minimal power available. Safety features, such as payload power management and thermal control, are considered with minimal user input. Three radiometers measure atmospheric brightness temperature at frequency at around 20, 40, and 50 GHz. Retrieval process yields temperature and humidity profiles with cross track scan along the flight line. Estimated total weight of all radiometer hardware, from the antennas to data acquisition system, is less than 0.8 kg and a maximum power consumption is 15.2 W. With not enough power for blackbody calibration target, radiometers use zenith sky view at lower stratosphere as an excellent calibration target for a conventional tipping-curve calibration. Spatial distributions of clouds from visible and surface temperature from thermal cameras are used as additional information for

  15. System for beaming power from earth to a high altitude platform

    Science.gov (United States)

    Friedman, Herbert W.; Porter, Terry J.

    2002-01-01

    Power is transmitted to a high altitude platform by an array of diode pumped solid state lasers each operated at a single range of laser wavelengths outside of infrared and without using adaptive optics. Each laser produces a beam with a desired arrival spot size. An aircraft avoidance system uses a radar system for automatic control of the shutters of the lasers.

  16. Endurance training at altitude.

    Science.gov (United States)

    Saunders, Philo U; Pyne, David B; Gore, Christopher J

    2009-01-01

    Since the 1968 Olympic Games when the effects of altitude on endurance performance became evident, moderate altitude training ( approximately 2000 to 3000 m) has become popular to improve competition performance both at altitude and sea level. When endurance athletes are exposed acutely to moderate altitude, a number of physiological responses occur that can comprise performance at altitude; these include increased ventilation, increased heart rate, decreased stroke volume, reduced plasma volume, and lower maximal aerobic power ((.)Vo(2max)) by approximately 15% to 20%. Over a period of several weeks, one primary acclimatization response is an increase in the volume of red blood cells and consequently of (.)Vo(2max). Altitudes > approximately 2000 m for >3 weeks and adequate iron stores are required to elicit these responses. However, the primacy of more red blood cells for superior sea-level performance is not clear-cut since the best endurance athletes in the world, from Ethiopia (approximately 2000 to 3000 m), have only marginally elevated hemoglobin concentrations. The substantial reduction in (.)Vo(2max) of athletes at moderate altitude implies that their training should include adequate short-duration (approximately 1 to 2 min), high-intensity efforts with long recoveries to avoid a reduction in race-specific fitness. At the elite level, athlete performance is not dependent solely on (.)Vo(2max), and the "smallest worthwhile change" in performance for improving race results is as little as 0.5%. Consequently, contemporary statistical approaches that utilize the concept of the smallest worthwhile change are likely to be more appropriate than conventional statistical methods when attempting to understand the potential benefits and mechanisms of altitude training.

  17. Assessing high altitude glacier thickness, volume and area changes using field, GIS and remote sensing techniques: the case of Nevado Coropuna (Peru

    Directory of Open Access Journals (Sweden)

    P. Peduzzi

    2010-08-01

    Full Text Available Higher temperatures and changes in precipitation patterns have induced an acute decrease in Andean glaciers, thus leading to additional stress on water supply. To adapt to climate changes, local governments need information on the rate of glacier area and volume losses and on current ice thickness. Remote sensing analyses of Coropuna glacier (Peru delineate an acute glaciated area decline between 1955 and 2008. We tested how volume changes can be estimated with remote sensing and GIS techniques using digital elevation models derived from both topographic maps and satellite images. Ice thickness was measured in 2004 using a Ground Penetrating Radar coupled with a Ground Positioning System during a field expedition. It provided profiles of ice thickness on different slopes, orientations and altitudes. These were used to model the current glacier volume using Geographical Information System and statistical multiple regression techniques. The results revealed a significant glacier volume loss; however the uncertainty is higher than the measured volume loss. We also provided an estimate of the remaining volume. The field study provided the scientific evidence needed by COPASA, a local Peruvian NGO, and GTZ, the German international cooperation agency, in order to alert local governments and communities and guide them in adopting new climate change adaptation policies.

  18. Integrating the EMPD with an Alpine altitudinal training set to reconstruct climate variables in Holocene pollen records from high-altitude peat bogs

    Science.gov (United States)

    Furlanetto, Giulia; Badino, Federica; Brunetti, Michele; Champvillair, Elena; De Amicis, Mattia; Maggi, Valter; Pini, Roberta; Ravazzi, Cesare; Vallé, Francesca

    2016-04-01

    Temperatures and precipitation are the main environmental factors influencing vegetation and pollen production. Knowing the modern climate optima and tolerances of those plants represented in fossil assemblages and assuming that the relationships between plants and climate in the past are not dissimilar from the modern ones, fossil pollen records offer many descriptors to reconstruct past climate variables. The aim of our work is to investigate the potential of high-altitude pollen records from an Alpine peat bog (TBValter, close to the Ruitor Glacier, Western Italian Alps) for quantitative paleoclimate estimates. The idea behind is that high-altitude ecosystems are more sensitive to climate changes, especially to changes in July temperatures that severely affect the timberline ecotone. Meantime, we met with difficulties when considering the factors involved in pollen dispersal over a complex altitudinal mountain pattern, such as the Alps. We used the EMPD-European Modern Pollen Database (Davis et al., 2013) as modern training set to be compared with our high-altitude fossil site. The EMPD dataset is valuable in that it provides a large geographic coverage of main ecological and climate gradients (at sub-continental scale) but lacks in sampling of altitudinal gradients and high-altitude sites in the Alps. We therefore designed an independent altitudinal training set for the alpine valley hosting our fossil site. 27 sampling plots were selected along a 1700m-elevational transect. In a first step, each plot was provided with (i) 3 moss polsters collected following the guidelines provided by Cañellas-Boltà et al. (2009) and analyzed separately to account for differences in pollen deposition at small scale, (ii) morphometrical parameters obtained through a high-resolution DEM, and (iii) temperature and precipitation were estimated by means of weighted linear regression of the meteorological variable versus elevation, locally evaluated for each site (Brunetti et al

  19. [Relationship between occupational stress and working ability of workers in a petroleum processing enterprise in high altitude area].

    Science.gov (United States)

    Ma, X M; Kang, H L; Shi, C B; Li, Y; Wu, Y F; Liu, Z H; Wang, G; Lei, H Y

    2017-12-20

    Objective: To investigate the relationship between occupational stress and working ability of workers in a petroleum processing enterprise in a high altitude area. Methods: A total of 728 workers in a petroleum processing enterprise at an altitude of 2850 m were subjected to a survey using Occupational Stress Inventory (OSI) , Work Ability Index (WAI) Scale, Occupational Role Questionnaire (ORQ) , Personal Strain Questionnaire (PSQ) , and Personal Resource Questionnaire (PRQ) from May 2014 to August 2016. Results: Of the 728 workers, 55 (7.6%) had a poor working ability, moderate in 262 (35.9%) , and good in 411 (56.5%). There were significant differences in WAI between the workers with different types of work, sexes, ages, and working years ( P occupational stress groups ( P Occupational stress is an influencing factor for the working ability of workers in the petroleum processing enterprise in the high altitude area. Hypoxia in high altitude area may further reduce the working ability. In order to reduce occupational stress and improve work ability, it should be considered to strengthen skills training, improve the working environment, and pay attention to mental health.

  20. Evidence for propagation of cold-adapted yeast in an ice core from a Siberian Altai glacier

    Science.gov (United States)

    Uetake, Jun; Kohshima, Shiro; Nakazawa, Fumio; Takeuchi, Nozomu; Fujita, Koji; Miyake, Takayuki; Narita, Hideki; Aizen, Vladimir; Nakawo, Masayoshi

    2011-03-01

    Cold environments, including glacier ice and snow, are known habitats for cold-adapted microorganisms. We investigated the potential for cold-adapted yeast to have propagated in the snow of the high-altitude Belukha glacier. We detected the presence of highly concentrated yeast (over 104 cells mL-1) in samples of both an ice core and firn snow. Increasing yeast cell concentrations in the same snow layer from July 2002 to July 2003 suggests that the yeast cells propagated in the glacier snow. A cold-adapted Rhodotorula sp. was isolated from the snow layer and found to be related to psychrophilic yeast previously found in other glacial environments (based on the D1/D2 26S rRNA domains). 26S rRNA clonal analysis directly amplified from meltwater within the ice core also revealed the presence of genus Rhodotorula. Analyses of the ice core showed that all peaks in yeast concentration corresponded to the peaks in indices of surface melting. These results support the hypothesis that occasional surface melting in an accumulation area is one of the major factors influencing cold-adapted yeast propagation.

  1. ICESat-2, its retrievals of ice sheet elevation change and sea ice freeboard, and potential synergies with CryoSat-2

    Science.gov (United States)

    Neumann, Thomas; Markus, Thorsten; Smith, Benjamin; Kwok, Ron

    2017-04-01

    Understanding the causes and magnitudes of changes in the cryosphere remains a priority for Earth science research. Over the past decade, NASA's and ESA's Earth-observing satellites have documented a decrease in both the areal extent and thickness of Arctic sea ice, and an ongoing loss of grounded ice from the Greenland and Antarctic ice sheets. Understanding the pace and mechanisms of these changes requires long-term observations of ice-sheet mass, sea-ice thickness, and sea-ice extent. NASA's ICESat-2 mission is the next-generation space-borne laser altimeter mission and will use three pairs of beams, each pair separated by about 3 km across-track with a pair spacing of 90 m. The spot size is 17 m with an along-track sampling interval of 0.7 m. This measurement concept is a result of the lessons learned from the original ICESat mission. The multi-beam approach is critical for removing the effects of ice sheet surface slope from the elevation change measurements of most interest. For sea ice, the dense spatial sampling (eliminating along-track gaps) and the small footprint size are especially useful for sea surface height measurements in the, often narrow, leads needed for sea ice freeboard and ice thickness retrievals. Currently, algorithms are being developed to calculate ice sheet elevation change and sea ice freeboard from ICESat-2 data. The orbits of ICESat-2 and Cryosat-2 both converge at 88 degrees of latitude, though the orbit altitude differences result in different ground track patterns between the two missions. This presentation will present an overview of algorithm approaches and how ICESat-2 and Cryosat-2 data may augment each other.

  2. An Initial Study of the Fundamentals of Ice Crystal Icing Physics in the NASA Propulsion Systems Laboratory

    Science.gov (United States)

    Struk, Peter M.; Ratvasky, Thomas P.; Bencic, Timothy J.; Van Zante, Judith F.; King, Michael C.; Tsao, Jen-Ching; Bartkus, Tadas P.

    2017-01-01

    This paper presents results from an initial study of the fundamental physics of ice-crystal ice accretion using the NASA Propulsion Systems Lab (PSL). Ice accretion due to the ingestion of ice-crystals is being attributed to numerous jet-engine power-loss events. The NASA PSL is an altitude jet-engine test facility which has recently added a capability to inject ice particles into the flow. NASA is evaluating whether this facility, in addition to full-engine and motor-driven-rig tests, can be used for more fundamental ice-accretion studies that simulate the different mixed-phase icing conditions along the core flow passage of a turbo-fan engine compressor. The data from such fundamental accretion tests will be used to help develop and validate models of the accretion process. The present study utilized a NACA0012 airfoil. The mixed-phase conditions were generated by partially freezing the liquid-water droplets ejected from the spray bars. This paper presents data regarding (1) the freeze out characteristics of the cloud, (2) changes in aerothermal conditions due to the presence of the cloud, and (3) the ice accretion characteristics observed on the airfoil model. The primary variable in this test was the PSL plenum humidity which was systematically varied for two duct-exit-plane velocities (85 and 135 ms) as well as two particle size clouds (15 and 50 m MVDi). The observed clouds ranged from fully glaciated to fully liquid, where the liquid clouds were at least partially supercooled. The air total temperature decreased at the test section when the cloud was activated due to evaporation. The ice accretions observed ranged from sharp arrow-like accretions, characteristic of ice-crystal erosion, to cases with double-horn shapes, characteristic of supercooled water accretions.

  3. Wilderness medicine at high altitude: recent developments in the field

    OpenAIRE

    Shah, Neeraj M; Hussain, Sidra; Cooke, Mark; O’Hara, John P; Mellor, Adrian

    2015-01-01

    Neeraj M Shah,1 Sidra Hussain,2 Mark Cooke,3 John P O’Hara,3 Adrian Mellor3,4 1Division of Asthma, Allergy and Lung Biology, King’s College London, UK; 2School of Medicine, University College London, London, UK; 3Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK; 4Academic Department of Military Anaesthesia and Critical Care, Royal Centre for Defence Medicine, Birmingham, UK Abstract: Travel to high altitude is increasingly p...

  4. Highly Conductive Carbon Fiber Reinforced Concrete for Icing Prevention and Curing.

    Science.gov (United States)

    Galao, Oscar; Bañón, Luis; Baeza, Francisco Javier; Carmona, Jesús; Garcés, Pedro

    2016-04-12

    This paper aims to study the feasibility of highly conductive carbon fiber reinforced concrete (CFRC) as a self-heating material for ice formation prevention and curing in pavements. Tests were carried out in lab ambient conditions at different fixed voltages and then introduced in a freezer at -15 °C. The specimens inside the freezer were exposed to different fixed voltages when reaching +5 °C for prevention of icing and when reaching the temperature inside the freezer, i.e. , -15 °C, for curing of icing. Results show that this concrete could act as a heating element in pavements with risk of ice formation, consuming a reasonable amount of energy for both anti-icing (prevention) and deicing (curing), which could turn into an environmentally friendly and cost-effective deicing method.

  5. High-Altitude Cirrus Clouds and Climate

    Indian Academy of Sciences (India)

    2002-12-03

    , thunder or lightning, rainbows or halos. A cloud is a visible aggregate of tiny water droplets or ice crystals suspended in the air. Most clouds result from cooling due to lifting of moisture containing air. Those associated with ...

  6. Composition and Morphology of Major Particle Types from Airborne Measurements during ICE-T and PRADACS Field Studies

    Science.gov (United States)

    Venero, I. M.; Mayol-Bracero, O. L.; Anderson, J. R.

    2012-12-01

    As part of the Puerto Rican African Dust and Cloud Study (PRADACS) and the Ice in Clouds Experiment - Tropical (ICE-T), we sampled giant airborne particles to study their elemental composition, morphology, and size distributions. Samples were collected in July 2011 during field measurements performed by NCAR's C-130 aircraft based on St Croix, U.S Virgin Island. The results presented here correspond to the measurements done during research flight #8 (RF8). Aerosol particles with Dp > 1 um were sampled with the Giant Nuclei Impactor and particles with Dp 4000 ft) showed the highest concentrations of clay material. HYSPLIT back trajectories for all samples showed that the low altitude samples initiated in the free troposphere in the Atlantic Ocean, which may account for the high sea salt content and that the source of the high altitude samples was closer to the Saharan - Sahel desert region and, therefore, these samples possibly had the influence of African dust. Size distribution results for quartz and unreacted sea-salt aerosols collected on the Giant Nuclei Impactor showed that sample RF08 - 12:05 UTM (300 ft) had the largest size value (mean = 2.936 μm) than all the other samples. Additional information was also obtained from the Wyoming Inlet present at the C - 130 aircraft which showed that size distribution results for all particles were smaller in size. The different mineral components of the dust have different size distributions so that a fractionation process could occur during transport. Also, the presence of supermicron sea salt at altitude is important for cloud processes.

  7. Large high altitude air shower observatory (LHAASO) project

    International Nuclear Information System (INIS)

    He Huihai

    2010-01-01

    The Large High Altitude Air Shower Observatory (LHAASO) project focuses mainly on the study of 40 GeV-1 PeV gamma ray astronomy and 10 TeV-1 EeV cosmic ray physics. It consists of a 1 km 2 extensive air shower array with 40 000 m 2 muon detectors, 90,000m 2 water Cerenkov detector array, 5 000 m 2 shower core detector array and an air Cerenkov/fluorescence telescope array. Prototype detectors are designed with some of them already in operation. A prototype array of 1% size of LHAASO will be built at the Yangbajing Cosmic Ray Observatory and used to coincidently measure cosmic rays with the ARGO-YBJ experiment. (authors)

  8. Radiation doses at high altitudes and during space flights

    International Nuclear Information System (INIS)

    Spurny, F.

    2001-01-01

    There are three main sources of radiation exposure during space flights and at high altitudes--galactic cosmic radiation, solar cosmic radiation and radiation of the earth's radiation belt. Their basic characteristics are presented in the first part of this paper.Man's exposure during space flights is discussed in the second part of the paper. Particular attention is devoted to the quantitative and qualitative characteristics of the radiation exposure on near-earth orbits: both theoretical estimation as well as experimental data are presented. Some remarks on radiation protection rules on-board space vehicles are also given.The problems connected with the radiation protection of air crew and passengers of subsonic and supersonic air transport are discussed in the last part of the paper. General characteristics of on-board radiation fields and their variations with flight altitude, geomagnetic parameters of a flight and the solar activity are presented, both based on theoretical estimates and experimental studies. The questions concerning air crew and passenger radiation protection arising after the publication of ICRP 60 recommendation are also discussed. Activities of different institutions relevant to the topic are mentioned; strategies to manage and check this type of radiation exposure are presented and discussed. Examples of results based on the author's personal experience are given, analyzed and discussed. (author)

  9. High-resolution boundary conditions of an old ice target near Dome C, Antarctica

    Science.gov (United States)

    Young, Duncan A.; Roberts, Jason L.; Ritz, Catherine; Frezzotti, Massimo; Quartini, Enrica; Cavitte, Marie G. P.; Tozer, Carly R.; Steinhage, Daniel; Urbini, Stefano; Corr, Hugh F. J.; van Ommen, Tas; Blankenship, Donald D.

    2017-08-01

    A high-resolution (1 km line spacing) aerogeophysical survey was conducted over a region near the East Antarctic Ice Sheet's Dome C that may hold a 1.5 Myr climate record. We combined new ice thickness data derived from an airborne coherent radar sounder with unpublished data that was in part unavailable for earlier compilations, and we were able to remove older data with high positional uncertainties. We generated a revised high-resolution digital elevation model (DEM) to investigate the potential for an old ice record in this region, and used laser altimetry to confirm a Cryosat-2 derived DEM for inferring the glaciological state of the candidate area. By measuring the specularity content of the bed, we were able to find an additional 50 subglacial lakes near the candidate site, and by Doppler focusing the radar data, we were able to map out the roughness of the bed at length scales of hundreds of meters. We find that the primary candidate region contains elevated rough topography interspersed with scattered subglacial lakes and some regions of smoother bed. Free subglacial water appears to be restricted from bed overlain by ice thicknesses of less than 3000 m. A site near the ice divide was selected for further investigation. The high resolution of this ice thickness data set also allows us to explore the nature of ice thickness uncertainties in the context of radar geometry and processing.

  10. Reaching High Altitudes on Mars with an Inflatable Hypersonic Drag Balloon (Ballute)

    CERN Document Server

    Griebel, Hannes

    2010-01-01

    The concept of probing the atmosphere of planet Mars by means of a hypersonic drag balloon, a device known as a “ballute”, is a novel approach to planetary science. In this concept, the probe deploys an inflatable drag body out in space and may then enter the atmosphere either once or several times until it slowly descends towards the ground, taking continuous atmospheric and other readings across a large altitude and ground range. Hannes Griebel discusses the theory behind such a mission along with experience gained during its practical implementation, such as mission design, manufacturing, packing and deployment techniques as well as ground and flight tests. The author also studies other ballute applications, specifically emergency low Earth orbit recovery and delivering payloads to high altitude landing sites on Mars.

  11. Acute and Chronic Altitude-Induced Cognitive Dysfunction in Children and Adolescents.

    Science.gov (United States)

    Rimoldi, Stefano F; Rexhaj, Emrush; Duplain, Hervé; Urben, Sébastien; Billieux, Joël; Allemann, Yves; Romero, Catherine; Ayaviri, Alejandro; Salinas, Carlos; Villena, Mercedes; Scherrer, Urs; Sartori, Claudio

    2016-02-01

    To assess whether exposure to high altitude induces cognitive dysfunction in young healthy European children and adolescents during acute, short-term exposure to an altitude of 3450 m and in an age-matched European population permanently living at this altitude. We tested executive function (inhibition, shifting, and working memory), memory (verbal, short-term visuospatial, and verbal episodic memory), and speed processing ability in: (1) 48 healthy nonacclimatized European children and adolescents, 24 hours after arrival at high altitude and 3 months after return to low altitude; (2) 21 matched European subjects permanently living at high altitude; and (3) a matched control group tested twice at low altitude. Short-term hypoxia significantly impaired all but 2 (visuospatial memory and processing speed) of the neuropsychological abilities that were tested. These impairments were even more severe in the children permanently living at high altitude. Three months after return to low altitude, the neuropsychological performances significantly improved and were comparable with those observed in the control group tested only at low altitude. Acute short-term exposure to an altitude at which major tourist destinations are located induces marked executive and memory deficits in healthy children. These deficits are equally marked or more severe in children permanently living at high altitude and are expected to impair their learning abilities. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Protective effect of total flavonoids of seabuckthorn (Hippophae rhamnoides) in simulated high-altitude polycythemia in rats.

    Science.gov (United States)

    Zhou, Ji-Yin; Zhou, Shi-Wen; Du, Xiao-Huang; Zeng, Sheng-Ya

    2012-09-28

    Seabuckthorn (Hippophae rhamnoides L.) has been used to treat high altitude diseases. The effects of five-week treatment with total flavonoids of seabuckthorn (35, 70, 140 mg/kg, ig) on cobalt chloride (5.5 mg/kg, ip)- and hypobaric chamber (simulating 5,000 m)-induced high-altitude polycythemia in rats were measured. Total flavonoids decreased red blood cell number, hemoglobin, hematocrit, mean corpuscular hemoglobin levels, span of red blood cell electrophoretic mobility, aggregation index of red blood cell, plasma viscosity, whole blood viscosity, and increased deformation index of red blood cell, erythropoietin level in serum. Total flavonoids increased pH, pO₂, Sp(O₂), pCO₂ levels in arterial blood, and increased Na⁺, HCO₃⁻, Cl⁻, but decreased K⁺ concentrations. Total flavonoids increased mean arterial pressure, left ventricular systolic pressure, end-diastolic pressure, maximal rate of rise and decrease, decreased heart rate and protected right ventricle morphology. Changes in hemodynamic, hematologic parameters, and erythropoietin content suggest that administration of total flavonoids from seabuckthorn may be useful in the prevention of high altitude polycythaemia in rats.

  13. A Decade of High-Resolution Arctic Sea Ice Measurements from Airborne Altimetry

    Science.gov (United States)

    Duncan, K.; Farrell, S. L.; Connor, L. N.; Jackson, C.; Richter-Menge, J.

    2017-12-01

    Satellite altimeters carried on board ERS-1,-2, EnviSat, ICESat, CryoSat-2, AltiKa and Sentinel-3 have transformed our ability to map the thickness and volume of the polar sea ice cover, on seasonal and decadal time-scales. The era of polar satellite altimetry has coincided with a rapid decline of the Arctic ice cover, which has thinned, and transitioned from a predominantly multi-year to first-year ice cover. In conjunction with basin-scale satellite altimeter observations, airborne surveys of the Arctic Ocean at the end of winter are now routine. These surveys have been targeted to monitor regions of rapid change, and are designed to obtain the full snow and ice thickness distribution, across a range of ice types. Sensors routinely deployed as part of NASA's Operation IceBridge (OIB) campaigns include the Airborne Topographic Mapper (ATM) laser altimeter, the frequency-modulated continuous-wave snow radar, and the Digital Mapping System (DMS). Airborne measurements yield high-resolution data products and thus present a unique opportunity to assess the quality and characteristics of the satellite observations. We present a suite of sea ice data products that describe the snow depth and thickness of the Arctic ice cover during the last decade. Fields were derived from OIB measurements collected between 2009-2017, and from reprocessed data collected during ad-hoc sea ice campaigns prior to OIB. Our bespoke algorithms are designed to accommodate the heterogeneous sea ice surface topography, that varies at short spatial scales. We assess regional and inter-annual variability in the sea ice thickness distribution. Results are compared to satellite-derived ice thickness fields to highlight the sensitivities of satellite footprints to the tails of the thickness distribution. We also show changes in the dynamic forcing shaping the ice pack over the last eight years through an analysis of pressure-ridge sail-height distributions and surface roughness conditions

  14. Late winter biogeochemical conditions under sea ice in the Canadian High Arctic

    Directory of Open Access Journals (Sweden)

    Helen S. Findlay

    2015-12-01

    Full Text Available With the Arctic summer sea-ice extent in decline, questions are arising as to how changes in sea-ice dynamics might affect biogeochemical cycling and phenomena such as carbon dioxide (CO2 uptake and ocean acidification. Recent field research in these areas has concentrated on biogeochemical and CO2 measurements during spring, summer or autumn, but there are few data for the winter or winter–spring transition, particularly in the High Arctic. Here, we present carbon and nutrient data within and under sea ice measured during the Catlin Arctic Survey, over 40 days in March and April 2010, off Ellef Ringnes Island (78° 43.11′ N, 104° 47.44′ W in the Canadian High Arctic. Results show relatively low surface water (1–10 m nitrate (<1.3 µM and total inorganic carbon concentrations (mean±SD=2015±5.83 µmol kg−1, total alkalinity (mean±SD=2134±11.09 µmol kg−1 and under-ice pCO2sw (mean±SD=286±17 µatm. These surprisingly low wintertime carbon and nutrient conditions suggest that the outer Canadian Arctic Archipelago region is nitrate-limited on account of sluggish mixing among the multi-year ice regions of the High Arctic, which could temper the potential of widespread under-ice and open-water phytoplankton blooms later in the season.

  15. Altitude and endurance training.

    Science.gov (United States)

    Rusko, Heikki K; Tikkanen, Heikki O; Peltonen, Juha E

    2004-10-01

    The benefits of living and training at altitude (HiHi) for an improved altitude performance of athletes are clear, but controlled studies for an improved sea-level performance are controversial. The reasons for not having a positive effect of HiHi include: (1) the acclimatization effect may have been insufficient for elite athletes to stimulate an increase in red cell mass/haemoglobin mass because of too low an altitude (altitude training period (training effect at altitude may have been compromised due to insufficient training stimuli for enhancing the function of the neuromuscular and cardiovascular systems; and (3) enhanced stress with possible overtraining symptoms and an increased frequency of infections. Moreover, the effects of hypoxia in the brain may influence both training intensity and physiological responses during training at altitude. Thus, interrupting hypoxic exposure by training in normoxia may be a key factor in avoiding or minimizing the noxious effects that are known to occur in chronic hypoxia. When comparing HiHi and HiLo (living high and training low), it is obvious that both can induce a positive acclimatization effect and increase the oxygen transport capacity of blood, at least in 'responders', if certain prerequisites are met. The minimum dose to attain a haematological acclimatization effect is > 12 h a day for at least 3 weeks at an altitude or simulated altitude of 2100-2500 m. Exposure to hypoxia appears to have some positive transfer effects on subsequent training in normoxia during and after HiLo. The increased oxygen transport capacity of blood allows training at higher intensity during and after HiLo in subsequent normoxia, thereby increasing the potential to improve some neuromuscular and cardiovascular determinants of endurance performance. The effects of hypoxic training and intermittent short-term severe hypoxia at rest are not yet clear and they require further study.

  16. Modelling snow ice and superimposed ice on landfast sea ice in Kongsfjorden, Svalbard

    Directory of Open Access Journals (Sweden)

    Caixin Wang

    2015-08-01

    Full Text Available Snow ice and superimposed ice formation on landfast sea ice in a Svalbard fjord, Kongsfjorden, was investigated with a high-resolution thermodynamic snow and sea-ice model, applying meteorological weather station data as external forcing. The model shows that sea-ice formation occurs both at the ice bottom and at the snow/ice interface. Modelling results indicated that the total snow ice and superimposed ice, which formed at the snow/ice interface, was about 14 cm during the simulation period, accounting for about 15% of the total ice mass and 35% of the total ice growth. Introducing a time-dependent snow density improved the modelled results, and a time-dependent oceanic heat flux parameterization yielded reasonable ice growth at the ice bottom. Model results suggest that weather conditions, in particular air temperature and precipitation, as well as snow thermal properties and surface albedo are the most critical factors for the development of snow ice and superimposed ice in Kongsfjorden. While both warming air and higher precipitation led to increased snow ice and superimposed ice forming in Kongsfjorden in the model runs, the processes were more sensitive to precipitation than to air temperature.

  17. Interactive Ice Sheet Flowline Model for High School and College Students

    Science.gov (United States)

    Stearns, L. A.; Rezvanbehbahani, S.; Shankar, S.

    2017-12-01

    Teaching about climate and climate change is conceptually challenging. While teaching tools and lesson plans are rapidly evolving to help teachers and students improve their understanding of climate processes, there are very few tools targeting ice sheet and glacier dynamics. We have built an interactive ice sheet model that allows students to explore how Antarctic glaciers respond to different climate perturbations. Interactive models offer advantages that are hard to obtain in traditional classroom settings; users can systematically investigate hypothetical situations, explore the effects of modifying systems, and repeatedly observe how systems interrelate. As a result, this project provides a much-needed bridge between the data and models used by the scientific community and students in high school and college. We target our instructional and assessment activities to three high school and college students with the overall aim of increasing understanding of ice sheet dynamics and the different ways that ice sheets are impacted by climate change, while also improving their fundamental math skills.

  18. Agroforestry systems, nutrients in litter and microbial activity in soils cultivated with coffee at high altitude

    Directory of Open Access Journals (Sweden)

    Krystal de Alcantara Notaro

    2014-04-01

    Full Text Available Agroforestry systems are an alternative option for sustainable production management. These systems contain trees that absorb nutrients from deeper layers of the soil and leaf litter that help improve the soil quality of the rough terrain in high altitude areas, which are areas extremely susceptible to environmental degradation. The aim of this study was to characterize the stock and nutrients in litter, soil activity and the population of microorganisms in coffee (Coffea arabica L. plantations under high altitude agroforestry systems in the semi-arid region of the state of Pernambuco, Brazil. Samples were collected from the surface litter together with soil samples taken at two depths (0-10 and 10-20 cm from areas each subject to one of the following four treatments: agroforestry system (AS, native forest (NF, biodynamic system (BS and coffee control (CT.The coffee plantation had been abandoned for nearly 15 years and, although there had been no management or harvesting, still contained productive coffee plants. The accumulation of litter and mean nutrient content of the litter, the soil nutrient content, microbial biomass carbon, total carbon, total nitrogen, C/N ratio, basal respiration, microbial quotient, metabolic quotient and microbial populations (total bacteria, fluorescent bacteria group, total fungi and Trichoderma spp. were all analyzed. The systems thatwere exposed to human intervention (A and BS differed in their chemical attributes and contained higher levels of nutrients when compared to NF and CT. BS for coffee production at high altitude can be used as a sustainable alternative in the high altitude zones of the semi-arid region in Brazil, which is an area that is highly susceptible to environmental degradation.

  19. Performance changes during a weeklong high-altitude alpine ski-racing training camp in lowlander young athletes.

    Science.gov (United States)

    Hydren, Jay R; Kraemer, William J; Volek, Jeff S; Dunn-Lewis, Courtenay; Comstock, Brett A; Szivak, Tunde K; Hooper, David R; Denegar, Craig R; Maresh, Carl M

    2013-04-01

    Thousands of youth athletes travel to high altitude to participate in lift-access alpine sports. The purpose of this study was to examine the impact of acute high-altitude exposure on balance, choice reaction time, power, quickness, flexibility, strength endurance, and V[Combining Dot Above]O2max in youth lowlander athletes during a weeklong preseason training camp in Summit County, CO, USA. Eleven youth ski racers (4 boys and 7 girls; age, 13.7 ± 0.5 years; height, 157.2 ± 12.6 cm; weight, 52.4 ± 6.8 kg) with 7.7 ± 2.2 skiing years of experience participated in baseline testing at 160 m one week before the camp and a set of daily tests in the morning and afternoon at 2,828 m and skied between 3,328 and 3,802 m during a 6-day camp. Balance and choice reaction time tests were stagnant or improved slightly during the first 3 days and then improved on days 4 and 6. Vertical jump, flexibility, T-agility test, and push-ups in 1 minute improved on day 6. The number of sit-ups in 1 minute did not improve, and scores on the multistage fitness test decreased 20.34%. There was no effect of Lake Louise acute mountain sickness (AMS) questionnaire scores on performance variables measured. Athletes sojourning to high altitude for ski camps can train on immediate ascent but should slowly increase training volume over the first 3 days. Athletes should expect improvements in balance and reaction time 3-6 days into acclimatization. Coaches and athletes should expect about 20% of youth lowlander athletes to have signs and symptoms of AMS during the first 3 days of altitude exposure for alpine lift access sports at altitudes of up to 3,800 m.

  20. Factors associated with poor balance ability in older adults of nine high-altitude communities.

    Science.gov (United States)

    Urrunaga-Pastor, Diego; Moncada-Mapelli, Enrique; Runzer-Colmenares, Fernando M; Bailon-Valdez, Zaira; Samper-Ternent, Rafael; Rodriguez-Mañas, Leocadio; Parodi, Jose F

    2018-05-01

    Poor balance ability in older adults result in multiple complications. Poor balance ability has not been studied among older adults living at high altitudes. In this study, we analysed factors associated with poor balance ability by using the Functional Reach (FR) among older adults living in nine high-altitude communities. Analytical cross-sectional study, carried out in inhabitants aged 60 or over from nine high-altitude Andean communities of Peru during 2013-2016. FR was divided according to the cut-off point of 8 inches (20.32 cm) and two groups were generated: poor balance ability (FR less or equal than 20.32 cm) and good balance ability (greater than 20.32 cm). Additionally, we collected socio-demographic, medical, functional and cognitive assessment information. Poisson regression models were constructed to identify factors associated with poor balance ability. Prevalence ratio (PR) with 95% confidence intervals (95CI%) are presented. A total of 365 older adults were studied. The average age was 73.0 ± 6.9 years (range: 60-91 years), and 180 (49.3%) participants had poor balance ability. In the adjusted Poisson regression analysis, the factors associated with poor balance ability were: alcohol consumption (PR = 1.35; 95%CI: 1.05-1.73), exhaustion (PR = 2.22; 95%CI: 1.49-3.31), gait speed (PR = 0.67; 95%CI: 0.50-0.90), having had at least one fall in the last year (PR = 2.03; 95%CI: 1.19-3.46), having at least one comorbidity (PR = 1.60; 95%CI: 1.10-2.35) and having two or more comorbidities (PR = 1.61; 95%CI: 1.07-2.42) compared to none. Approximately a half of the older adults from these high-altitude communities had poor balance ability. Interventions need to be designed to target these balance issues and prevent adverse events from concurring to these individuals. Copyright © 2018 Elsevier B.V. All rights reserved.

  1. Reducing pulmonary injury by hyperbaric oxygen preconditioning during simulated high altitude exposure in rats.

    Science.gov (United States)

    Li, Zhuo; Gao, Chunjin; Wang, Yanxue; Liu, Fujia; Ma, Linlin; Deng, Changlei; Niu, Ko-Chi; Lin, Mao-Tsun; Wang, Chen

    2011-09-01

    Hyperbaric oxygen preconditioning (HBO₂P + HAE) has been found to be beneficial in preventing the occurrence of ischemic damage to brain, spinal cord, heart, and liver in several disease models. In addition, pulmonary inflammation and edema are associated with a marked reduction in the expression levels of both aquaporin (AQP) 1 and AQP5 in the lung. Here, the aims of this study are first to ascertain whether acute lung injury can be induced by simulated high altitude in rats and second to assess whether HBO2P + HAE is able to prevent the occurrence of the proposed high altitude-induced ALI. Rats were randomly divided into the following three groups: the normobaric air (NBA; 21% O₂ at 1 ATA) group, the HBO₂P + high altitude exposure (HAE) group, and the NBA + HAE group. In HBO₂P + HAE group, animals received 100% O₂ at 2.0 ATA for 1 hour per day, for five consecutive days. In HAE groups, animals were exposed to a simulated HAE of 6,000 m in a hypobaric chamber for 24 hours. Right after being taken out to the ambient, animals were anesthetized generally and killed and thoroughly exsanguinated before their lungs were excised en bloc. The lungs were used for both histologic and molecular evaluation and analysis. In NBA + HAE group, the animals displayed higher scores of alveolar edema, neutrophil infiltration, and hemorrhage compared with those of NBA controls. In contrast, the levels of both AQP1 and AQP5 proteins and mRNA expression in the lung in the NBA + HAE group were significantly lower than those of NBA controls. However, the increased lung injury scores and the decreased levels of both AQP1 and AQP5 proteins and mRNA expression in the lung caused by HAE was significantly reduced by HBO₂P + HAE. Our results suggest that high altitude pulmonary injury may be prevented by HBO2P + HAE in rats.

  2. Highly Conductive Carbon Fiber Reinforced Concrete for Icing Prevention and Curing

    Directory of Open Access Journals (Sweden)

    Oscar Galao

    2016-04-01

    Full Text Available This paper aims to study the feasibility of highly conductive carbon fiber reinforced concrete (CFRC as a self-heating material for ice formation prevention and curing in pavements. Tests were carried out in lab ambient conditions at different fixed voltages and then introduced in a freezer at −15 °C. The specimens inside the freezer were exposed to different fixed voltages when reaching +5 °C for prevention of icing and when reaching the temperature inside the freezer, i.e., −15 °C, for curing of icing. Results show that this concrete could act as a heating element in pavements with risk of ice formation, consuming a reasonable amount of energy for both anti-icing (prevention and deicing (curing, which could turn into an environmentally friendly and cost-effective deicing method.

  3. The effect of α1‐adrenergic blockade on post‐exercise brachial artery flow‐mediated dilatation at sea level and high altitude

    Science.gov (United States)

    Tremblay, Joshua C.; Hansen, Alex B.; Howe, Connor A.; Willie, Chris K.; Stembridge, Mike; Green, Daniel J.; Hoiland, Ryan L.; Subedi, Prajan; Anholm, James D.; Ainslie, Philip N.

    2016-01-01

    Key points Our objective was to quantify endothelial function (via brachial artery flow‐mediated dilatation) at sea level (344 m) and high altitude (3800 m) at rest and following both maximal exercise and 30 min of moderate‐intensity cycling exercise with and without administration of an α1‐adrenergic blockade.Brachial endothelial function did not differ between sea level and high altitude at rest, nor following maximal exercise.At sea level, endothelial function decreased following 30 min of moderate‐intensity exercise, and this decrease was abolished with α1‐adrenergic blockade. At high altitude, endothelial function did not decrease immediately after 30 min of moderate‐intensity exercise, and administration of α1‐adrenergic blockade resulted in an increase in flow‐mediated dilatation.Our data indicate that post‐exercise endothelial function is modified at high altitude (i.e. prolonged hypoxaemia). The current study helps to elucidate the physiological mechanisms associated with high‐altitude acclimatization, and provides insight into the relationship between sympathetic nervous activity and vascular endothelial function. Abstract We examined the hypotheses that (1) at rest, endothelial function would be impaired at high altitude compared to sea level, (2) endothelial function would be reduced to a greater extent at sea level compared to high altitude after maximal exercise, and (3) reductions in endothelial function following moderate‐intensity exercise at both sea level and high altitude are mediated via an α1‐adrenergic pathway. In a double‐blinded, counterbalanced, randomized and placebo‐controlled design, nine healthy participants performed a maximal‐exercise test, and two 30 min sessions of semi‐recumbent cycling exercise at 50% peak output following either placebo or α1‐adrenergic blockade (prazosin; 0.05 mg kg −1). These experiments were completed at both sea‐level (344 m) and high altitude (3800

  4. Changes in labial capillary density on ascent to and descent from high altitude [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Edward Gilbert-Kawai

    2016-08-01

    Full Text Available Present knowledge of how the microcirculation is altered by prolonged exposure to hypoxia at high altitude is incomplete and modification of existing analytical techniques may improve our knowledge considerably. We set out to use a novel simplified method of measuring in vivo capillary density during an expedition to high altitude using a CytoCam incident dark field imaging video-microscope. The simplified method of data capture involved recording one-second images of the mucosal surface of the inner lip to reveal data about microvasculature density in ten individuals. This was done on ascent to, and descent from, high altitude. Analysis was conducted offline by two independent investigators blinded to the participant identity, testing conditions and the imaging site.  Additionally we monitored haemoglobin concentration and haematocrit data to see if we could support or refute mechanisms of altered density relating to vessel recruitment. Repeated sets of paired values were compared using Kruskall Wallis Analysis of Variance tests, whilst comparisons of values between sites was by related samples Wilcoxon Signed Rank Test. Correlation between different variables was performed using Spearman’s rank correlation coefficient, and concordance between analysing investigators using intra-class correlation coefficient. There was a significant increase in capillary density from London on ascent to high altitude; median capillaries per field of view area increased from 22.8 to 25.3 (p=0.021. There was a further increase in vessel density during the six weeks spent at altitude (25.3 to 32.5, p=0.017. Moreover, vessel density remained high on descent to Kathmandu (31.0 capillaries per field of view area, despite a significant decrease in haemoglobin concentration and haematocrit. Using a simplified technique, we have demonstrated an increase in capillary density on early and sustained exposure to hypobaric hypoxia at thigh altitude, and that this remains

  5. Effects of High Altitude on Sleep and Respiratory System and Theirs Adaptations

    Directory of Open Access Journals (Sweden)

    Turhan San

    2013-01-01

    Full Text Available High-altitude (HA environments have adverse effects on the normal functioning body of people accustomed to living at low altitudes because of the change in barometric pressure which causes decrease in the amount of oxygen leading to hypobaric hypoxia. Sustained exposure to hypoxia has adverse effects on body weight, muscle structure and exercise capacity, mental functioning, and sleep quality. The most important step of acclimatization is the hyperventilation which is achieved by hypoxic ventilatory response of the peripheral chemoreceptors. Hyperventilation results in increase in arterial carbondioxide concentration. Altitude also affects sleep and cardiac output, which is the other determinant of oxygen delivery. Upon initial exposure to HA, the resting pulse rate increases rapidly, but with acclimatization, heart rate and cardiac output tend to fall. Another important component that leads to decrease in cardiac output is the reduction in the stroke volume with acclimatization. During sleep at HA, the levels of CO2 in the blood can drop very low and this can switch off the drive to breathe. Only after the body senses a further drop in O2 levels breathing is started again. Periodic breathing is thought to result from instability in the control system through the hypoxic drive or the response to CO2.

  6. Grappling the High Altitude for Safe Edible Bamboo Shoots with Rich Nutritional Attributes and Escaping Cyanogenic Toxicity

    Directory of Open Access Journals (Sweden)

    Sayanika Devi Waikhom

    2013-01-01

    Full Text Available Consumption of bamboo species with high level of total cyanogenic content (TCC in Asia by many ethnic groups is significantly associated with food poisoning and occasionally Konzo (a neurological disorder. Adequate characterization of edible bamboo species with low level of TCC and high nutritious attributes is required for consumer’s safety as well as for the conservation of the gene pool. Here, we employed morphological descriptors, atomic absorption spectrophotometer, RAPD, and trnL-F intergenic spacer to characterize 15 indigenous edible bamboo species of north-east India. The study indicates that morphologically and genetically evolved edible bamboo species having large and robust bamboo-shoot texture and growing at low altitude contain high level of TCC, low antioxidant properties, and low levels of beneficial macronutrients and micronutrients. Importantly, Dendrocalamus species are shown to be rich in TCC irrespective of the growing altitude while Bambusa species are found to have moderate level of TCC. The findings clearly demonstrated that Chimonobambusa callosa growing at high altitude represents safe edible bamboo species with nutritious attributes.

  7. Imaging Findings of a Survivor of Avalanche without Any Life Support at Very High Altitude and Extreme Low Temperatures

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    Abhishek Dwivedi

    2016-10-01

    Full Text Available Survival at high altitude is very challenging and in spite of adequate training and acclimatization, injuries are frequent. The fate of mountaineers and soldiers at such areas largely depends on the mercy of the climate. An avalanche causes physical trauma, cold injury and asphyxia to the victim. The patient in our report had diffuse cerebral edema, bilateral pulmonary consolidation and pneumothorax. In spite of the best efforts the victim succumbed to the injuries. There are many incidents of high altitude accidents in India. This case report is of a soldier deployed at the high altitude, is a lone ever reported survivor above 5000 meters, under 35 feet snow and below - 45°C for greater than 5 days of exposure to an avalanche

  8. Exercise and Training at Altitudes: Physiological Effects and Protocols

    Directory of Open Access Journals (Sweden)

    Olga Cecilia Vargas Pinilla

    2014-01-01

    Full Text Available An increase in altitude leads to a proportional fall in the barometric pressure, and a decrease in atmospheric oxygen pressure, producing hypobaric hypoxia that affects, in different degrees, all body organs, systems and functions. The chronically reduced partial pressure of oxygen causes that individuals adapt and adjust to physiological stress. These adaptations are modulated by many factors, including the degree of hypoxia related to altitude, time of exposure, exercise intensity and individual conditions. It has been established that exposure to high altitude is an environmental stressor that elicits a response that contributes to many adjustments and adaptations that influence exercise capacity and endurance performance. These adaptations include in crease in hemoglobin concentration, ventilation, capillary density and tissue myoglobin concentration. However, a negative effect in strength and power is related to a decrease in muscle fiber size and body mass due to the decrease in the training intensity. Many researches aim at establishing how training or living at high altitudes affects performance in athletes. Training methods, such as living in high altitudes training low, and training high-living in low altitudes have been used to research the changes in the physical condition in athletes and how the physiological adaptations to hypoxia can enhanceperformance at sea level. This review analyzes the literature related to altitude training focused on how physiological adaptations to hypoxic environments influence performance, and which protocols are most frequently used to train in high altitudes.

  9. Excessive Iron Availability Caused by Disorders of Interleukin-10 and Interleukin-22 Contributes to High Altitude Polycythemia

    Directory of Open Access Journals (Sweden)

    Yun-Sheng Liu

    2018-05-01

    Full Text Available Background: Because the pathogenesis of high altitude polycythemia (HAPC is unclear, the aim of the present study was to explore whether abnormal iron metabolism is involved in the pathogenesis of HAPC and the possible cause.Methods: We examined the serum levels of iron, total iron binding capacity, soluble transferrin receptor (sTfR, ferritin, and hepcidin as well as erythropoietin (EPO and inflammation-related cytokines in 20 healthy volunteers at sea level, 36 healthy high-altitude migrants, and 33 patients with HAPC. Mice that were exposed to a simulated hypoxic environment at an altitude of 5,000 m for 4 weeks received exogenous iron or intervention on cytokines, and the iron-related and hematological indices of peripheral blood and bone marrow were detected. The in vitro effects of some cytokines on hematopoietic cells were also observed.Results: Iron mobilization and utilization were enhanced in people who had lived at high altitudes for a long time. Notably, both the iron storage in ferritin and the available iron in the blood were elevated in patients with HAPC compared with the healthy high-altitude migrants. The correlation analysis indicated that the decreased hepcidin may have contributed to enhanced iron availability in HAPC, and decreased interleukin (IL-10 and IL-22 were significantly associated with decreased hepcidin. The results of the animal experiments confirmed that a certain degree of iron redundancy may promote bone marrow erythropoiesis and peripheral red blood cell production in hypoxic mice and that decreased IL-10 and IL-22 stimulated iron mobilization during hypoxia by affecting hepcidin expression.Conclusion: These data demonstrated, for the first time, that an excess of obtainable iron caused by disordered IL-10 and IL-22 was involved in the pathogenesis of some HAPC patients. The potential benefits of iron removal and immunoregulation for the prevention and treatment of HAPC deserve further research.

  10. Surname-inferred Andean ancestry is associated with child stature and limb lengths at high altitude in Peru, but not at sea level.

    Science.gov (United States)

    Pomeroy, Emma; Wells, Jonathan C K; Stanojevic, Sanja; Miranda, J Jaime; Moore, Lorna G; Cole, Tim J; Stock, Jay T

    2015-01-01

    Native Andean ancestry gives partial protection from reduced birthweight at high altitude in the Andes compared with European ancestry. Whether Andean ancestry is also associated with body proportions and greater postnatal body size at altitude is unknown. Therefore, we tested whether a greater proportion of Andean ancestry is associated with stature and body proportions among Peruvian children at high and low altitude. Height, head circumference, head-trunk height, upper and lower limb lengths, and tibia, ulna, hand and foot lengths, were measured in 133 highland and 169 lowland children aged 6 months to 8.5 years. For highland and lowland groups separately, age-sex-adjusted anthropometry z scores were regressed on the number of indigenous parental surnames as a proxy for Andean ancestry, adjusting for potential confounders (maternal age and education, parity, altitude [highlands only]). Among highland children, greater Andean ancestry was negatively associated with stature and tibia, ulna, and lower limb lengths, independent of negative associations with greater altitude for these measurements. Relationships were strongest for tibia length: each additional Andean surname or 1,000 m increase at altitude among highland children was associated with 0.18 and 0.65 z score decreases in tibia length, respectively. Anthropometry was not significantly associated with ancestry among lowland children. Greater Andean ancestry is associated with shorter stature and limb measurements at high but not low altitude. Gene-environment interactions between high altitude and Andean ancestry may exacerbate the trade-off between chest dimensions and stature that was proposed previously, though we could not test this directly. © 2015 Wiley Periodicals, Inc.

  11. International Workshop on Comparing Ice Nucleation Measuring Systems 2014

    Energy Technology Data Exchange (ETDEWEB)

    Cziczo, Daniel [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2016-04-30

    The relationship of ambient aerosol particles to the formation of ice-containing clouds is one of the largest uncertainties in understanding the Earth’s climate. The uncertainty is due to several poorly understood processes and measurements including, but not limited to: (1) the microphysics of how particles nucleate ice, (2) the number of ice forming particles as a function of atmospheric properties such as temperature and relative humidity, (3) the atmospheric distribution of ice forming particles and (4) the role of anthropogenic activities in producing or changing the behavior of ice forming particles. The ways in which ice forming particles can impact climate is also multi-faceted. More ice forming particles can lead to clouds with more ice crystals and different optical properties than clouds with less ice forming particles. More effective ice forming particles can lead to ice at higher temperature and/or lower saturation, resulting in clouds at lower altitude or latitude which also changes the Earth’s radiative balance. Ice nucleation also initiates most of the Earth’s precipitation, even in the mid- and low-latitudes, since cloud-top temperatures are often below freezing. The limited measurements and lack of understanding directly translates to restrictions in our ability to model atmospheric ice formation and project changes into the future. The importance of ice nucleation research is further exemplified by Figure 1 which shows the publications per decade and citations per year on the topic of ice nucleation [DeMott et al., 2011]. After a lull at the end of the last century, there has been a dramatic increase in both publications and citations related to ice nucleation; this directly corresponds to the importance of ice nucleation on the Earth’s climate and the uncertainty in this area noted by the Solomon [2007].

  12. Hemoglobin and hematocrit values of Saudi newborns in the high altitude of Abha, Saudi Arabia

    International Nuclear Information System (INIS)

    Bassuni, W.; Asindi, A.A.; Mustafa, F.S.; Hassan, B.; Din, Z.S.; Kumar, R.K.

    1996-01-01

    A study was designed to determine the red cell values (hemoglobin and hematocrit) of neonates born in the high altitude of Abha and to compare these values with known values of other lowland areas of Saudi Arabia. From the cord blood of 587 normal, appropriate for gestational age and term infants born in 1993 in Abha Maternity Hospital, the ranges of Hb and Hct were 130 to 240 g/L and 0.24 to 0.79 L/L respectively. The mean Hb was 187 g/L. There was no significant difference between the male and female values. Also, 17% of the infants in this study were polycythemic, while no polycythemia was recorded in these lowland areas and only 2% to 4% in the general global newborn population. It was therefore revealed that Abha newborns had higher red cell values at the birth when compared to other newborns in the low altitude areas of Riyadh and Jeddah (P<0.001). We postulate that high altitude (2700 meters above sea level) of Abha, and therefore its relative hypoxia, has induced high red cell values in infants born in the city. The phenomenon therefore warrants the adoption of higher red cell reference values and not necessarily those already documented in other Saudi new born populations. (author)

  13. Applied high-speed imaging for the icing research program at NASA Lewis Research Center

    Science.gov (United States)

    Slater, Howard; Owens, Jay; Shin, Jaiwon

    1992-01-01

    The Icing Research Tunnel at NASA Lewis Research Center provides scientists a scaled, controlled environment to simulate natural icing events. The closed-loop, low speed, refrigerated wind tunnel offers the experimental capability to test for icing certification requirements, analytical model validation and calibration techniques, cloud physics instrumentation refinement, advanced ice protection systems, and rotorcraft icing methodology development. The test procedures for these objectives all require a high degree of visual documentation, both in real-time data acquisition and post-test image processing. Information is provided to scientific, technical, and industrial imaging specialists as well as to research personnel about the high-speed and conventional imaging systems will be on the recent ice protection technology program. Various imaging examples for some of the tests are presented. Additional imaging examples are available from the NASA Lewis Research Center's Photographic and Printing Branch.

  14. Snow chemistry of high altitude glaciers in the French Alps

    OpenAIRE

    MAUPETIT, FRANÇOIS; DELMAS, ROBERT J.

    2011-01-01

    Snow samples were collected as snowcores in the accumulation zone of four high altitude glaciers (2980–3540 m.a.s.l.) from each of the 4 highest mountain areas of the French Alps, during 3 consecutive years: 1989, 1990 and 1991. Sampling was performed in spring (∼ May), before the onset of late spring–summer percolation. The accumulated snow therefore reflects winter and spring conditions. A complementary sampling of fresh-snow was performed on an event basis, on one of the studied glaciers, ...

  15. Lower obesity rate during residence at high altitude among a military population with frequent migration: a quasi experimental model for investigating spatial causation.

    Directory of Open Access Journals (Sweden)

    Jameson D Voss

    Full Text Available We sought to evaluate whether residence at high altitude is associated with the development of obesity among those at increased risk of becoming obese. Obesity, a leading global health priority, is often refractory to care. A potentially novel intervention is hypoxia, which has demonstrated positive long-term metabolic effects in rats. Whether or not high altitude residence confers benefit in humans, however, remains unknown. Using a quasi-experimental, retrospective study design, we observed all outpatient medical encounters for overweight active component enlisted service members in the U.S. Army or Air Force from January 2006 to December 2012 who were stationed in the United States. We compared high altitude (>1.96 kilometers above sea level duty assignment with low altitude (<0.98 kilometers. The outcome of interest was obesity related ICD-9 codes (278.00-01, V85.3x-V85.54 by Cox regression. We found service members had a lower hazard ratio (HR of incident obesity diagnosis if stationed at high altitude as compared to low altitude (HR 0.59, 95% confidence interval [CI] 0.54-0.65; p<0.001. Using geographic distribution of obesity prevalence among civilians throughout the U.S. as a covariate (as measured by the Centers for Disease Control and Prevention and the REGARDS study also predicted obesity onset among service members. In conclusion, high altitude residence predicts lower rates of new obesity diagnoses among overweight service members in the U.S. Army and Air Force. Future studies should assign exposure using randomization, clarify the mechanism(s of this relationship, and assess the net balance of harms and benefits of high altitude on obesity prevention.

  16. Characteristics of high altitude oxygen ion energization and outflow as observed by Cluster: a statistical study

    Energy Technology Data Exchange (ETDEWEB)

    Nilsson, H.; Waara, M.; Arvelius, S.; Yamauchi, M.; Lundin, R. [Inst. of Space Physics, Kiruna (Sweden); Marghitu, O. [Max-Planck-Inst. fuer Extraterrestriche Physik, Garching (Germany); Inst. for Space Sciences, Bucharest (Romania); Bouhram, M. [Max-Planck-Inst. fuer Extraterrestriche Physik, Garching (Germany); CETP-CNRS, Saint-Maur (France); Hobara, Y. [Inst. of Space Physics, Kiruna (Sweden); Univ. of Sheffield, Sheffield (United Kingdom); Reme, H.; Sauvaud, J.A.; Dandouras, I. [Centre d' Etude Spatiale des Rayonnements, Toulouse (France); Balogh, A. [Imperial Coll. of Science, Technology and Medicine, London (United Kingdom); Kistler, L.M. [Univ. of New Hampshire, Durham (United States); Klecker, B. [Max-Planck-Inst. fuer Extraterrestriche Physik, Garching (Germany); Carlson, C.W. [Space Science Lab., Univ. of California, Berkeley (United States); Bavassano-Cattaneo, M.B. [Ist. di Fisica dello Spazio Interplanetario, Roma (Italy); Korth, A. [Max-Planck-Inst. fuer Sonnensystemforschung, Katlenburg-Lindau (Germany)

    2006-07-01

    The results of a statistical study of oxygen ion outflow using cluster data obtained at high altitude above the polar cap is reported. Moment data for both hydrogen ions (H{sup +}) and oxygen ions (O{sup +}) from 3 years (2001-2003) of spring orbits (January to May) have been used. The altitudes covered were mainly in the range 5-12 R{sub E} geocentric distance. It was found that O{sup +} is significantly transversely energized at high altitudes, indicated both by high perpendicular temperatures for low magnetic field values as well as by a tendency towards higher perpendicular than parallel temperature distributions for the highest observed temperatures. The O{sup +} parallel bulk velocity increases with altitude in particular for the lowest observed altitude intervals. O{sup +} parallel bulk velocities in excess of 60 km s{sup -1} were found mainly at higher altitudes corresponding to magnetic field strengths of less than 100 nT. For the highest observed parallel bulk velocities of O{sup +} the thermal velocity exceeds the bulk velocity, indicating that the beam-like character of the distribution is lost. The parallel bulk velocity of the H{sup +} and O{sup +} was found to typically be close to the same throughout the observation interval when the H{sup +} bulk velocity was calculated for all pitch-angles. When the H{sup +} bulk velocity was calculated for upward moving particles only the H{sup +} parallel bulk velocity was typically higher than that of O{sup +}. The parallel bulk velocity is close to the same for a wide range of relative abundance of the two ion species, including when the O{sup +} ions dominates. The thermal velocity of O{sup +} was always well below that of H{sup +}. Thus perpendicular energization that is more effective for O{sup +} takes place, but this is not enough to explain the close to similar parallel velocities. Further parallel acceleration must occur. The results presented constrain the models of perpendicular heating and parallel

  17. Characteristics of high altitude oxygen ion energization and outflow as observed by Cluster: a statistical study

    Directory of Open Access Journals (Sweden)

    H. Nilsson

    2006-05-01

    Full Text Available The results of a statistical study of oxygen ion outflow using Cluster data obtained at high altitude above the polar cap is reported. Moment data for both hydrogen ions (H+ and oxygen ions (O+ from 3 years (2001-2003 of spring orbits (January to May have been used. The altitudes covered were mainly in the range 5–12 RE geocentric distance. It was found that O+ is significantly transversely energized at high altitudes, indicated both by high perpendicular temperatures for low magnetic field values as well as by a tendency towards higher perpendicular than parallel temperature distributions for the highest observed temperatures. The O+ parallel bulk velocity increases with altitude in particular for the lowest observed altitude intervals. O+ parallel bulk velocities in excess of 60 km s-1 were found mainly at higher altitudes corresponding to magnetic field strengths of less than 100 nT. For the highest observed parallel bulk velocities of O+ the thermal velocity exceeds the bulk velocity, indicating that the beam-like character of the distribution is lost. The parallel bulk velocity of the H+ and O+ was found to typically be close to the same throughout the observation interval when the H+ bulk velocity was calculated for all pitch-angles. When the H+ bulk velocity was calculated for upward moving particles only the H+ parallel bulk velocity was typically higher than that of O+. The parallel bulk velocity is close to the same for a wide range of relative abundance of the two ion species, including when the O+ ions dominates. The thermal velocity of O+ was always well below that of H+. Thus perpendicular energization that is more effective for O+ takes place, but this is not enough to explain the close to similar parallel velocities. Further parallel acceleration must occur. The results presented constrain the models of perpendicular heating and parallel acceleration. In particular centrifugal acceleration of the outflowing ions, which may

  18. Incidence and care of environmental dermatoses in the high-altitude region of Ladakh, India

    Directory of Open Access Journals (Sweden)

    G K Singh

    2013-01-01

    Full Text Available Background : Low humidity, high-velocity wind, excessive ultraviolet (UV exposure, and extreme cold temperature are the main causes of various types of environmental dermatoses in high altitudes. Materials and Methods: A retrospective study was carried out in patients visiting the lone dermatology department in Ladakh between July 2009 and June 2010. The aim was to identify the common environmental dermatoses in high altitudes so that they can be treated easily or prevented. The patients were divided into three demographic groups, namely, lowlanders, Ladakhis (native highlanders, and tourists. Data was analyzed in a tabulated fashion. Results: A total of 1,567 patients with skin ailments were seen, of whom 965 were lowlanders, 512 native Ladakhis, and 90 were tourists. The skin disorders due to UV rays, dry skin, and papular urticaria were common among all groups. The frequency of melasma ( n = 42; 49.4%, chronic actinic dermatitis (CAD ( n = 18; 81.81% of total CAD cases, and actinic cheilitis ( n = 3; 100% was much higher among the native Ladakhis. The frequency of cold-related injuries was much lesser among Ladakhis ( n = 1; 1.19% than lowlanders ( n = 70; 83.33% and tourists ( n = 13; 15.47% ( P < 0.05. Conclusion: Dryness of skin, tanning, acute or chronic sunburn, polymorphic light reaction, CAD, insect bite reactions, chilblain, and frostbite are common environmental dermatoses of high altitudes. Avoidance of frequent application of soap, application of adequate and suitable emollient, use of effective sunscreen, and wearing of protective clothing are important guidelines for skin care in this region.

  19. Protective effects of Astragalus-Lilygranules on intestinal mucosal barrier of mice in high altitude hypoxia

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    Ling LI

    2016-10-01

    Full Text Available Objective  To investigate the protective effect of Astragalus-Lily Granules on intestinal mucosa and intestinal flora homeostasis in mice under high altitude hypoxia condition. Methods  We put mice into high altitude hypoxia cabin to establish high altitude hypoxia model mice. Sixty Kunming mice were randomly divided into control group, model group, Astragalus-Lily particles (ALP low, medium and high dose groups [1.75, 3.5, 7g/(kg•d] respectively. After three days of routine feeding, the ALP mice received drug by intragastric administration, once a day for continuous 17 days,control group and model group were given double distilled water in same volume. From the 15th day, all the mice but control group were exposed to simulated high altitude hypoxia condition for 3 days in a high altitude hypoxia cabin after they were gavaged for half an hour daily. By the 18th day, the fresh mouse feces were collected and smeared to observe the changes of microflora. The pathological changes of intestinal tissues were observed by HE staining and the expression of HIF-1αprotein in intestines was detected by immunohistochemistry. Results  The enterococci and gram negative bacteria showed a higher proportion (65.2%±2.4% and 56.7%±3.3%, respectively in the model group compared with the control group (24.7%±1.2%, 23.2%±1.5%, respectively, P<0.05. The pathological score of intestinal mucosal necrosis and edema (3.10±0.99, 3.30±0.67 respectively and inflammatory cell count (15.93±3.30, 16.40±3.97/ HP respectively was higher compared with the model group (0.70±0.67, 0.80±0.78; 4.07±2.12, 4.28±2.16/HP respectively; P<0.05. HIF-1αexpression increased significantly compared with the model group (P<0.05. The enterococci (46.7%±2.0%, 32.0%±2.6% respectively and gram negative bacteria rate (34.2%±1.6%, 38.0%±2.8% respectively in the ALP medium and high dose groups were lower compared with the model group (24.7%±1.2%, 23.2%±1.5% respectively, P<0

  20. High-altitude and high-latitude O+ and H+ outflows: the effect of finite electromagnetic turbulence wavelength

    Directory of Open Access Journals (Sweden)

    I. A. Barghouthi

    2007-11-01

    , consistent with the observations of H+ and O+ ions in the auroral region at high altitudes.

  1. Adaptive remodeling of skeletal muscle energy metabolism in high-altitude hypoxia: Lessons from AltitudeOmics.

    Science.gov (United States)

    Chicco, Adam J; Le, Catherine H; Gnaiger, Erich; Dreyer, Hans C; Muyskens, Jonathan B; D'Alessandro, Angelo; Nemkov, Travis; Hocker, Austin D; Prenni, Jessica E; Wolfe, Lisa M; Sindt, Nathan M; Lovering, Andrew T; Subudhi, Andrew W; Roach, Robert C

    2018-05-04

    Metabolic responses to hypoxia play important roles in cell survival strategies and disease pathogenesis in humans. However, the homeostatic adjustments that balance changes in energy supply and demand to maintain organismal function under chronic low oxygen conditions remain incompletely understood, making it difficult to distinguish adaptive from maladaptive responses in hypoxia-related pathologies. We integrated metabolomic and proteomic profiling with mitochondrial respirometry and blood gas analyses to comprehensively define the physiological responses of skeletal muscle energy metabolism to 16 days of high-altitude hypoxia (5260 m) in healthy volunteers from the AltitudeOmics project. In contrast to the view that hypoxia down-regulates aerobic metabolism, results show that mitochondria play a central role in muscle hypoxia adaptation by supporting higher resting phosphorylation potential and enhancing the efficiency of long-chain acylcarnitine oxidation. This directs increases in muscle glucose toward pentose phosphate and one-carbon metabolism pathways that support cytosolic redox balance and help mitigate the effects of increased protein and purine nucleotide catabolism in hypoxia. Muscle accumulation of free amino acids favor these adjustments by coordinating cytosolic and mitochondrial pathways to rid the cell of excess nitrogen, but might ultimately limit muscle oxidative capacity in vivo Collectively, these studies illustrate how an integration of aerobic and anaerobic metabolism is required for physiological hypoxia adaptation in skeletal muscle, and highlight protein catabolism and allosteric regulation as unexpected orchestrators of metabolic remodeling in this context. These findings have important implications for the management of hypoxia-related diseases and other conditions associated with chronic catabolic stress. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

  2. Cirrus Susceptibility to Changes in Ice Nuclei: Physical Processes, Model Uncertainties, and Measurement Needs

    Science.gov (United States)

    Jensen, Eric

    2018-01-01

    One of the proposed concepts for mitigating the warming effect of increasing greenhouse gases is seeding cirrus cloud with ice nuclei (IN) in order to reduce the lifetime and coverage of cold cirrus that have a net warming impact on the earth's surface. Global model simulations of the net impact of changing upper tropospheric IN have given widely disparate results, partly as a result of poor understanding of ice nucleation processes in the current atmosphere, and partly as a result of poor representation of these processes in global models. Here, we present detailed process-model simulations of tropical tropopause layer (TTL) transport and cirrus formation with ice nuclei properties based on recent laboratory nucleation experiments and field measurements of aerosol composition. The model is used to assess the sensitivity of TTL cirrus occurrence frequency and microphysical properties to the abundance and efficacy of ice nuclei. The simulated cloud properties compared with recent high-altitude aircraft measurements of TTL cirrus and ice supersaturation. We find that abundant effective IN (either from glassy organic aerosols or crystalline ammonium sulfate with concentrations greater than about 100/L) prevent the occurrences of large ice concentration and large ice supersaturations, both of which are clearly indicated by the in situ observations. We find that concentrations of effective ice nuclei larger than about 50/L can drive significant changes in cirrus microphysical properties and occurrence frequency. However, the cloud occurrence frequency can either increase or decrease, depending on the efficacy and abundance of IN added to the TTL. We suggest that our lack of information about ice nuclei properties in the current atmosphere, as well as uncertainties in ice nucleation processes and their representations in global models, preclude meaningful estimates of climate impacts associated with addition of ice nuclei in the upper troposphere. We will briefly discuss

  3. Serum creatine kinase elevations in ultramarathon runners at high altitude.

    Science.gov (United States)

    Magrini, Danielle; Khodaee, Morteza; San-Millán, Iñigo; Hew-Butler, Tamara; Provance, Aaron J

    2017-05-01

    Creatine kinase (CK) is a sensitive enzyme marker for muscle damage in athletes. Elevated CK levels have been reported in many endurance physical activities. The consequence and possible long-term sequela of the CK elevation in athletes is unknown. There is a paucity of literature stating actual numerical values of CK associated with competing in an ultramarathon with extreme environmental conditions. Our hypothesis was that the serum CK levels increase significantly as a result of running a 161 km ultramarathon at high altitude. This was a prospective observational study of participants of the Leadville 100 ultramarathon race in Leadville, Colorado at high altitude (2800-3840 m) in August 2014. We collected blood samples from sixty-four volunteer runners before and eighty-three runners immediately after the race. Out of 669 athletes who started the race, 352 successfully completed the race in less than the 30-hour cut-off time (52%). The majority of runners were male (84%). We were able to collect both pre- and post-race blood samples from 36 runners. Out of these 36 runners, the mean pre-race CK was increased from 126 ± 64 U/L to 14,569 ± 14,729 U/L (p athletes' age, BMI, or finishing time. Significant elevation of CK level occurs as a result of running ultramarathons. The majority of athletes with significantly elevated CK levels were asymptomatic and required no major medical attention.

  4. Beta-fibrinogen allele frequencies in Peruvian Quechua, a high-altitude native population.

    Science.gov (United States)

    Rupert, J L; Devine, D V; Monsalve, M V; Hochachka, P W

    1999-06-01

    Elevated hematocrits, which are found in many high-altitude populations, increase the oxygen-carrying capacity of blood and may represent an adaptation to hypoxic environments. However, as high hematocrit increases blood viscosity, which in turn is associated with hypertension and heart disease, it may be advantageous for high-altitude populations to limit other factors that contribute to increased blood viscosity. One such factor is the plasma concentration of the coagulation protein fibrinogen. Several common polymorphisms in the beta-fibrinogen gene have been identified that affect fibrinogen concentrations. We determined the allele frequencies of three of these polymorphisms (G/A-455(HaeIII), C/T-148(HindIII), and G/A+448(MnlI)) in sample groups drawn from three populations: Quechua-speaking natives living at over 3,200 m in the Peruvian Andes, North American natives (Na-Dene) from coastal British Columbia, and Caucasian North Americans. The frequencies of the alleles previously shown to be associated with increased fibrinogen levels were so low in the Quechuas that their presence could be accounted for solely by genetic admixture with Caucasians. Frequencies in the Na-Dene, a Native American group unrelated to the Quechua, were not significantly different from those in Caucasians.

  5. Mössbauer studies of hemoglobin in high altitude polycythemia

    Science.gov (United States)

    Xiufang, Zhang; Linming, Shen; Songsen, Chen; Yuanyuan, Liu; Naifei, Gao; Yuanming, Zheng; Zhaohui, Ao; Liangquan, Shong

    1990-07-01

    The Mössbauer spectra have been measured in erythrocytes from normal adults and the patients with high altitude polycythemia (HAPC). The results indicated that two subspectra “a” and “b”, corresponding to oxy- and deoxyhemoglobin respectively, were present in all blood samples, and a third subspectrum “c” was found to exist in almost all samples from the patients. The parameters of the third subspectra “cl” in most samples from the patients were similar to those of carbon monoxyhemoglobin. The components were considered to be the denatured hemoglobin in RBCs (red blood cells). Together with clinical analysis, a possible mechanism of HAPC has been discussed.

  6. Adjustment of measurement errors to reconcile precipitation distribution in the high-altitude Indus basin

    NARCIS (Netherlands)

    Dahri, Zakir Hussain; Moors, Eddy; Ludwig, Fulco; Ahmad, Shakil; Khan, Asif; Ali, Irfan; Kabat, Pavel

    2018-01-01

    Precipitation in the high-altitude Indus basin governs its renewable water resources affecting water, energy and food securities. However, reliable estimates of precipitation climatology and associated hydrological implications are seriously constrained by the quality of observed data. As such,

  7. Snow and Ice Particle Sizes and Mass Concentrations at Altitudes Up to 9 km (30,000 ft)

    National Research Council Canada - National Science Library

    Jeck, Richard

    1998-01-01

    About 7600 nautical miles (nm) (14,000 km) of select ice particle measurements over the United States have been compiled into a single, computerized database for use in characterizing ice crystal and snowflake...

  8. A 30-year record of surface mass balance (1966-95) and motion and surface altitude (1975-95) at Wolverine Glacier, Alaska

    Science.gov (United States)

    Mayo, Lawrence R.; Trabant, Dennis C.; March, Rod S.

    2004-01-01

    Scientific measurements at Wolverine Glacier, on the Kenai Peninsula in south-central Alaska, began in April 1966. At three long-term sites in the research basin, the measurements included snow depth, snow density, heights of the glacier surface and stratigraphic summer surfaces on stakes, and identification of the surface materials. Calculations of the mass balance of the surface strata-snow, new firn, superimposed ice, and old firn and ice mass at each site were based on these measurements. Calculations of fixed-date annual mass balances for each hydrologic year (October 1 to September 30), as well as net balances and the dates of minimum net balance measured between time-transgressive summer surfaces on the glacier, were made on the basis of the strata balances augmented by air temperature and precipitation recorded in the basin. From 1966 through 1995, the average annual balance at site A (590 meters altitude) was -4.06 meters water equivalent; at site B (1,070 meters altitude), was -0.90 meters water equivalent; and at site C (1,290 meters altitude), was +1.45 meters water equivalent. Geodetic determination of displacements of the mass balance stake, and glacier surface altitudes was added to the data set in 1975 to detect the glacier motion responses to variable climate and mass balance conditions. The average surface speed from 1975 to 1996 was 50.0 meters per year at site A, 83.7 meters per year at site B, and 37.2 meters per year at site C. The average surface altitudes were 594 meters at site A, 1,069 meters at site B, and 1,293 meters at site C; the glacier surface altitudes rose and fell over a range of 19.4 meters at site A, 14.1 meters at site B, and 13.2 meters at site C.

  9. WCDMA Uplink Interference Assessment from Multiple High Altitude Platform Configurations

    Directory of Open Access Journals (Sweden)

    Grace D

    2008-01-01

    Full Text Available Abstract We investigate the possibility of multiple high altitude platform (HAP coverage of a common cell area using a wideband code division multiple access (WCDMA system. In particular, we study the uplink system performance of the system. The results show that depending on the traffic demand and the type of service used, there is a possibility of deploying 3–6 HAPs covering the same cell area. The results also show the effect of cell radius on performance and the position of the multiple HAP base stations which give the worst performance.

  10. Collapse of the 2017 Winter Beaufort High: A Response to Thinning Sea Ice?

    Science.gov (United States)

    Moore, G. W. K.; Schweiger, A.; Zhang, J.; Steele, M.

    2018-03-01

    The winter Arctic atmosphere is under the influence of two very different circulation systems: extratropical cyclones travel along the primary North Atlantic storm track from Iceland toward the eastern Arctic, while the western Arctic is characterized by a quasi-stationary region of high pressure known as the Beaufort High. The winter (January through March) of 2017 featured an anomalous reversal of the normally anticyclonic surface winds and sea ice motion in the western Arctic. This reversal can be traced to a collapse of the Beaufort High as the result of the intrusion of low-pressure systems from the North Atlantic, along the East Siberian Coast, into the Arctic Basin. Thin sea ice as the result of an extremely warm autumn (October through December) of 2016 contributed to the formation of an anomalous thermal low over the Barents Sea that, along with a northward shift of the tropospheric polar vortex, permitted this intrusion. The collapse of the Beaufort High during the winter of 2017 was associated with simultaneous 2-sigma sea level pressure, surface wind, and sea ice circulation anomalies in the western Arctic. As the Arctic sea ice continues to thin, such reversals may become more common and impact ocean circulation, sea ice, and biology.

  11. Oxidative stress at high altitude: genotype–phenotype correlations

    Directory of Open Access Journals (Sweden)

    Pandey P

    2014-05-01

    Full Text Available Priyanka Pandey,1,2 MA Qadar Pasha1,2 1CSIR-Institute of Genomics and Integrative Biology, Delhi, India; 2Department of Biotechnology, University of Pune, Ganeshkhind, Pune, India Abstract: It has been well-documented that the hypobaric hypoxic environment at high altitude (HA causes stress to both the permanent residents of HA and the sojourners. This oxidative stress primarily disturbs the oxygen-sensing and vascular homeostasis pathways, thereby upsetting normal human physiology, especially in sojourners. These environmental challenges have caused dynamic evolutionary changes within natives of HA, allowing them to develop adaptive plasticity. This review focuses on the genomic and biochemical features of the molecules involved in the oxygen-sensing and vascular homeostasis pathways with respect to HA pulmonary edema (HAPE and adaptation. We review the role of genetic markers such as HIF-prolyl hydroxylase 2, endothelial PAS domain-containing protein 1, endothelial nitric oxide synthase, endothelin 1, cytochrome b-245 alpha polypeptide, and glutathione S-transferase pi 1, as well as three circulatory biomarkers (nitric oxide, endothelin 1, and 8-iso-prostaglandin F2α, by highlighting approaches such as candidate gene and genome-wide, adopted in deciphering the pathways. A disagreement between the two approaches has also been highlighted. In addition, we discuss that an overrepresentation of wild-type alleles in HA natives and mutant alleles of same polymorphisms in HAPE patients implies that the allelic variants at the same locus are involved in adaptation and HAPE, respectively. Moreover, healthy sojourners present a number of genomic features similar to HA natives, further strengthening the concept of genetic predisposition. A trend in correlation between protective and risk alleles and altered levels of circulatory markers clearly documents the phenomenon of genotype–phenotype correlations. We conclude that the genetic and biochemical

  12. Serum irisin and myostatin levels after 2 weeks of high-altitude climbing.

    Directory of Open Access Journals (Sweden)

    Ewa Śliwicka

    Full Text Available Exposure to high-altitude hypoxia causes physiological and metabolic adaptive changes by disturbing homeostasis. Hypoxia-related changes in skeletal muscle affect the closely interconnected energy and regeneration processes. The balance between protein synthesis and degradation in the skeletal muscle is regulated by several molecules such as myostatin, cytokines, vitamin D, and irisin. This study investigates changes in irisin and myostatin levels in male climbers after a 2-week high-altitude expedition, and their association with 25(OHD and indices of inflammatory processes. The study was performed in 8 men aged between 23 and 31 years, who participated in a 2-week climbing expedition in the Alps. The measurements of body composition and serum concentrations of irisin, myostatin, 25(OHD, interleukin-6, myoglobin, high-sensitivity C-reactive protein, osteoprotegerin, and high-sensitivity soluble receptor activator of NF-κB ligand (sRANKL were performed before and after expedition. A 2-week exposure to hypobaric hypoxia caused significant decrease in body mass, body mass index (BMI, free fat mass and irisin, 25-Hydroxyvitamin D levels. On the other hand, significant increase in the levels of myoglobin, high-sensitivity C-reactive protein, interleukin-6, and osteoprotegerin were noted. The observed correlations of irisin with 25(OHD levels, as well as myostatin levels with inflammatory markers and the OPG/RANKL ratio indicate that these myokines may be involved in the energy-related processes and skeletal muscle regeneration in response to 2-week exposure to hypobaric hypoxia.

  13. Serum irisin and myostatin levels after 2 weeks of high-altitude climbing.

    Science.gov (United States)

    Śliwicka, Ewa; Cisoń, Tomasz; Kasprzak, Zbigniew; Nowak, Alicja; Pilaczyńska-Szcześniak, Łucja

    2017-01-01

    Exposure to high-altitude hypoxia causes physiological and metabolic adaptive changes by disturbing homeostasis. Hypoxia-related changes in skeletal muscle affect the closely interconnected energy and regeneration processes. The balance between protein synthesis and degradation in the skeletal muscle is regulated by several molecules such as myostatin, cytokines, vitamin D, and irisin. This study investigates changes in irisin and myostatin levels in male climbers after a 2-week high-altitude expedition, and their association with 25(OH)D and indices of inflammatory processes. The study was performed in 8 men aged between 23 and 31 years, who participated in a 2-week climbing expedition in the Alps. The measurements of body composition and serum concentrations of irisin, myostatin, 25(OH)D, interleukin-6, myoglobin, high-sensitivity C-reactive protein, osteoprotegerin, and high-sensitivity soluble receptor activator of NF-κB ligand (sRANKL) were performed before and after expedition. A 2-week exposure to hypobaric hypoxia caused significant decrease in body mass, body mass index (BMI), free fat mass and irisin, 25-Hydroxyvitamin D levels. On the other hand, significant increase in the levels of myoglobin, high-sensitivity C-reactive protein, interleukin-6, and osteoprotegerin were noted. The observed correlations of irisin with 25(OH)D levels, as well as myostatin levels with inflammatory markers and the OPG/RANKL ratio indicate that these myokines may be involved in the energy-related processes and skeletal muscle regeneration in response to 2-week exposure to hypobaric hypoxia.

  14. Observations of ice nuclei and heterogeneous freezing in a Western Pacific extratropical storm

    Directory of Open Access Journals (Sweden)

    J. L. Stith

    2011-07-01

    Full Text Available In situ airborne sampling of refractory black carbon (rBC particles and Ice Nuclei (IN was conducted in and near an extratropical cyclonic storm in the western Pacific Ocean during the Pacific Dust Experiment, PACDEX, in the spring of 2007. Airmass origins were from Eastern Asia. Clouds associated primarily with the warm sector of the storm were sampled at various locations and altitudes. Cloud hydrometeors were evaporated by a counterflow virtual impactor (CVI and the residuals were sampled by a single particle soot photometer (SP2 instrument, a continuous flow diffusion chamber ice nucleus detector (CFDC and collected for electron microscope analysis. In clouds containing large ice particles, multiple residual particles were observed downstream of the CVI for each ice particle sampled on average. The fraction of rBC compared to total particles in the residual particles increased with decreasing condensed water content, while the fraction of IN compared to total particles did not, suggesting that the scavenging process for rBC is different than for IN. In the warm sector storm midlevels at temperatures where heterogeneous freezing is expected to be significant (here −24 to −29 °C, IN concentrations from ice particle residuals generally agreed with simultaneous measurements of total ice concentrations or were higher in regions where aggregates of crystals were found, suggesting heterogeneous freezing as the dominant ice formation process in the mid levels of these warm sector clouds. Lower in the storm, at warmer temperatures, ice concentrations were affected by aggregation and were somewhat less than measured IN concentrations at colder temperatures. The results are consistent with ice particles forming at storm mid-levels by heterogeneous freezing on IN, followed by aggregation and sedimentation to lower altitudes. Compositional analysis of the aerosol and back trajectories of the air in the warm sector suggested a possible biomass

  15. Arctic sea-ice ridges—Safe heavens for sea-ice fauna during periods of extreme ice melt?

    Science.gov (United States)

    Gradinger, Rolf; Bluhm, Bodil; Iken, Katrin

    2010-01-01

    The abundances and distribution of metazoan within-ice meiofauna (13 stations) and under-ice fauna (12 stations) were investigated in level sea ice and sea-ice ridges in the Chukchi/Beaufort Seas and Canada Basin in June/July 2005 using a combination of ice coring and SCUBA diving. Ice meiofauna abundance was estimated based on live counts in the bottom 30 cm of level sea ice based on triplicate ice core sampling at each location, and in individual ice chunks from ridges at four locations. Under-ice amphipods were counted in situ in replicate ( N=24-65 per station) 0.25 m 2 quadrats using SCUBA to a maximum water depth of 12 m. In level sea ice, the most abundant ice meiofauna groups were Turbellaria (46%), Nematoda (35%), and Harpacticoida (19%), with overall low abundances per station that ranged from 0.0 to 10.9 ind l -1 (median 0.8 ind l -1). In level ice, low ice algal pigment concentrations (Turbellaria, Nematoda and Harpacticoida also were observed in pressure ridges (0-200 ind l -1, median 40 ind l -1), although values were highly variable and only medians of Turbellaria were significantly higher in ridge ice than in level ice. Median abundances of under-ice amphipods at all ice types (level ice, various ice ridge structures) ranged from 8 to 114 ind m -2 per station and mainly consisted of Apherusa glacialis (87%), Onisimus spp. (7%) and Gammarus wilkitzkii (6%). Highest amphipod abundances were observed in pressure ridges at depths >3 m where abundances were up to 42-fold higher compared with level ice. We propose that the summer ice melt impacted meiofauna and under-ice amphipod abundance and distribution through (a) flushing, and (b) enhanced salinity stress at thinner level sea ice (less than 3 m thickness). We further suggest that pressure ridges, which extend into deeper, high-salinity water, become accumulation regions for ice meiofauna and under-ice amphipods in summer. Pressure ridges thus might be crucial for faunal survival during periods of

  16. High-Altitude Platforms - Present Situation and Technology Trends

    Directory of Open Access Journals (Sweden)

    Flavio Araripe D'Oliveira

    2016-07-01

    Full Text Available High-altitude platforms (HAPs are aircraft, usually unmanned airships or airplanes positioned above 20 km, in the stratosphere, in order to compose a telecommunications network or perform remote sensing. In the 1990 and 2000 decades, several projects were launched, but very few had continued. In 2014, 2 major Internet companies (Google and Facebook announced investments in new HAP projects to provide Internet access in regions without communication infrastructure (terrestrial or satellite, bringing back attention to the development of HAP. This article aims to survey the history of HAPs, the current state-of-the-art (April 2016, technology trends and challenges. The main focus of this review will be on technologies directly related to the aerial platform, inserted in the aeronautical engineering field of knowledge, not detailing aspects of the telecommunications area.

  17. Serum immunoreactive erythropoietin in high altitude natives with and without excessive erythrocytosis.

    Science.gov (United States)

    León-Velarde, F; Monge, C C; Vidal, A; Carcagno, M; Criscuolo, M; Bozzini, C E

    1991-05-01

    We report the estimation of blood hemoglobin (Hb), arterial blood oxygen saturation (SaO2), and serum immunoreactive erythropoietin (siEPO) in a group of Peruvian workers residing in Cerro de Pasco at 4300 m showing "excessive erythrocytosis" (EE, Monge's disease, chronic mountain sickness). These estimates were compared with those of humans residing either in Cerro de Pasco and showing "normal erythrocytosis" (NE) or in Lima (sea level, SL) to determine whether Hb and SaO2 are related to siEPO in high altitude (HA) natives with NE or EE. The three parameters showed statistically significant differences between HA and SL groups--the values in SL being lower. Significant differences were also found between NE and EE groups in Hb and SaO2. There was no statistical difference in siEPo between the two groups. The results indicate, therefore, that HA residents who develop EE are not distinguishable from residents who develop NE on the basis of estimates of siEPO. As a result, siEPO and Hb do not show a dose-response relationship in HA residents, and variation in EPO does not explain the striking variation in Hb at high altitudes.

  18. Haematology and erythrocyte metabolism in man at high altitude: an Aymara-Quechua comparison.

    Science.gov (United States)

    Arnaud, J; Gutierrez, N; Tellez, W; Vergnes, H

    1985-07-01

    In the course of haematological and biological investigations among Aymara and Quechua populations in Bolivia, an anthropological study of the erythrocytary respiratory function was carried out on the two groups at two altitudes: 3,600 m and 450 m. A difference in the intensity of the biological variations of the two populations is observed at high altitude. In the Quechuas, as in any lowland native, the adaptative phenomena are totally and quickly reversible. In the Aymaras, we detected the existence of more marked haematological and biochemical characters: moderate polycythemia, hyperhaemoglobinemia, microcytosis, metabolical hyperactivity with accumulation of 2-3 di-phosphoglycerate and ATP, and methaemoglobinemia with a drop in the activity of the methaemoglobin reductases. The Aymaras preserve some of those characters (methaemoglobinemia excepted) when they settle in lowlands.

  19. ABOUT TRANSITION ALTITUDE IN RUSSIAN FEDERATION

    Directory of Open Access Journals (Sweden)

    2016-01-01

    Full Text Available This article is about establishing a common transition altitude over all territory of Russian Federation. The main objective is to prove the necessity of a common transition altitude in Russian airspace and to define, which variant of tran- sition altitude (low, medium, high is the most suitable to be implemented in Russia. ICAO and IFALPA points of view, data and experience from different states and regions all over the world were examined in order to show all the advantages and disadvantages of different approaches towards common transition altitude. The research showed that the most appro- priate common transition altitude in Russia will be 10000 feet (3050 meters, it will cover almost all the international aero- dromes and regions in the country. Only several exceptions are needed in mountainous areas. This article can be used to further study of the possibility of implementation of common transition altitude, because it can’t take into consideration all the local features of all the FIRs (Flight Information Regions in Russia. The conclusion is establishing a common transi- tion altitude over such a big part of the world as Russian Federation will lead to improvement of the flight safety, harmoni- zation with ICAO and IFALPA policies and flexibility in airspace design.

  20. Trekking at high altitudes. How safe is it for your patients?

    Science.gov (United States)

    Houston, C S

    1990-07-01

    Even healthy persons may experience some form of altitude illness when they hike or ski in high mountains. Therefore, it is imperative that those with compromised cardiac or pulmonary function take extra precautions by allowing time for ascent, by recognizing and accepting their limitations, and by descending promptly at the first sign of trouble. Certain medications, such as anticoagulants and strong tranquilizers, are probably best discontinued at higher elevations. In all caes, preventive and treatment measures should be available.

  1. Mapping the depth to ice-cemented ground in the high elevation Dry Valleys, Antarctica

    Science.gov (United States)

    Marinova, M.; McKay, C. P.; Heldmann, J. L.; Davila, A. F.; Andersen, D. T.; Jackson, A.; Lacelle, D.; Paulsen, G.; Pollard, W. H.; Zacny, K.

    2011-12-01

    The high elevation Dry Valleys of Antarctica provide a unique location for the study of permafrost distribution and stability. In particular, the extremely arid and cold conditions preclude the presence of liquid water, and the exchange of water between the ice-cemented ground and the atmosphere is through vapour transport (diffusion). In addition, the low atmospheric humidity results in the desiccation of the subsurface, forming a dry permafrost layer (i.e., cryotic soils which are dry and not ice-cemented). Weather data suggests that subsurface ice is unstable under current climatic conditions. Yet we do find ice-cemented ground in these valleys. This contradiction provides insight into energy balance modeling, vapour transport, and additional climate effects which stabilize subsurface ice. To study the driving factors in the stability and distribution of ice-cemented ground, we have extensively mapped the depth to ice-cemented ground in University Valley (1730 m; 77°S 51.8', 160°E 43'), and three neighbouring valleys in the Beacon Valley area. We measured the depth to ice-cemented ground at 15-40 locations per valley by digging soil pits and drilling until ice was reached; for each location 3-5 measurements within a ~1 m2 area were averaged (see figure). This high-resolution mapping of the depth to ice-cemented ground provides new insight on the distribution and stability of subsurface ice, and shows significant variability in the depth to ground ice within each valley. We are combining data from mapping the depth to ice-cemented ground with year-round, in situ measurements of the atmospheric and subsurface conditions, such as temperature, humidity, wind, and light, to model the local stability of ice-cemented ground. We are using this dataset to examine the effects of slopes, shading, and soil properties, as well as the suggested importance of snow recurrence, to better understand diffusion-controlled subsurface ice stability.

  2. The HAMMER: High altitude multiple mission environmental researcher

    Science.gov (United States)

    Hayashi, Darren; Zylla, Cara; Amaro, Ernesto; Colin, Phil; Klause, Thomas; Lopez, Bernardo; Williamson, Danna

    1991-01-01

    At the equator, the ozone layer ranges from 65,000 to 130,000+ feet which is beyond the capabilities of the ER-2, NASA's current high altitude reconnaissance aircraft. The Universities Space Research Association, in cooperation with NASA, is sponsoring an undergraduate program which is geared to designing an aircraft that can study the ozone layer at the equator. This aircraft must be able to satisfy four mission profiles. Mission one is a polar mission which ranges from Chile to the South Pole and back to Chile, a total range of 6000 n. mi. at 100,000 feet with a 2500 lb. payload. The second mission is also a polar mission with a decreased altitude of 70,000 feet and an increased payload of 4000 lb. For the third mission, the aircraft will take-off at NASA Ames, cruise at 100,000 feet carrying a 2500 lb. payload, and land in Puerto Montt, Chile. The final mission requires the aircraft to take-off at NASA Ames, cruise at 100,000 feet with a 1000 lb. payload, make an excursion to 120,000 feet, and land at Howard AFB, Panama. All three missions require that a subsonic Mach number is maintained due to constraints imposed by the air sampling equipment. The aircraft need not be manned for all four missions. Three aircraft configurations were determined to be the most suitable for meeting the above requirements. The performance of each configuration is analyzed to investigate the feasibility of the project requirements. In the event that a requirement can not be obtained within the given constraints, recommendations for proposal modifications are given.

  3. Rate of ice accumulation during ice storms

    Energy Technology Data Exchange (ETDEWEB)

    Feknous, N. [SNC-Lavalin, Montreal, PQ (Canada); Chouinard, L. [McGill Univ., Montreal, PQ (Canada); Sabourin, G. [Hydro-Quebec, Montreal, PQ (Canada)

    2005-07-01

    The rate of glaze ice accumulation is the result of a complex process dependent on numerous meteorological and physical factors. The aim of this paper was to estimate the distribution rate of glaze ice accumulation on conductors in southern Quebec for use in the design of mechanical and electrical de-icing devices. The analysis was based on direct observations of ice accumulation collected on passive ice meters. The historical database of Hydro-Quebec, which contains observations at over 140 stations over period of 25 years, was used to compute accumulation rates. Data was processed so that each glaze ice event was numbered in a chronological sequence. Each event consisted of the time series of ice accumulations on each of the 8 cylinders of the ice meters, as well as on 5 of its surfaces. Observed rates were converted to represent the average ice on a 30 mm diameter conductor at 30 m above ground with a span of 300 m. Observations were corrected to account for the water content of the glaze ice as evidenced by the presence of icicles. Results indicated that despite significant spatial variations in the expected severity of ice storms as a function of location, the distribution function for rates of accumulation were fairly similar and could be assumed to be independent of location. It was concluded that the observations from several sites could be combined in order to obtain better estimates of the distribution of hourly rates of ice accumulation. However, the rates were highly variable. For de-icing strategies, it was suggested that average accumulation rates over 12 hour periods were preferable, and that analyses should be performed for other time intervals to account for the variability in ice accumulation rates over time. In addition, accumulation rates did not appear to be highly correlated with average wind speed for maximum hourly accumulation rates. 3 refs., 2 tabs., 10 figs.

  4. Changes in balance and joint position sense during a 12-day high altitude trek: The British Services Dhaulagiri medical research expedition.

    Directory of Open Access Journals (Sweden)

    Sarah B Clarke

    Full Text Available Postural control and joint position sense are essential for safely undertaking leisure and professional activities, particularly at high altitude. We tested whether exposure to a 12-day trek with a gradual ascent to high altitude impairs postural control and joint position sense. This was a repeated measures observational study of 12 military service personnel (28±4 years. Postural control (sway velocity measured by a portable force platform during standing balance, a Sharpened Romberg Test and knee joint position sense were measured, in England (113m elevation and at 3 research camps (3619m, 4600m and 5140m on a 12-day high altitude trek in the Dhaulagiri region of Nepal. Pulse oximetry, and Lake Louise scores were also recorded on the morning and evening of each trek day. Data were compared between altitudes and relationships between pulse oximetry, Lake Louise score, and sway velocity were explored. Total sway velocity during standing balance with eyes open (p = 0.003, d = 1.9 and during Sharpened Romberg test with eyes open (p = 0.007, d = 1.6 was significantly greater at altitudes of 3619m and 5140m when compared with sea level. Anterior-posterior sway velocity during standing balance with eyes open was also significantly greater at altitudes of 3619m and 5140m when compared with sea level (p = 0.001, d = 1.9. Knee joint position sense was not altered at higher altitudes. There were no significant correlations between Lake Louise scores, pulse oximetry and postural sway. Despite a gradual ascent profile, exposure to 3619 m was associated with impairments in postural control without impairment in knee joint position sense. Importantly, these impairments did not worsen at higher altitudes of 4600 m or 5140 m. The present findings should be considered during future trekking expeditions when developing training strategies targeted to manage impairments in postural control that occur with increasing altitude.

  5. Changes in balance and joint position sense during a 12-day high altitude trek: The British Services Dhaulagiri medical research expedition.

    Science.gov (United States)

    Clarke, Sarah B; Deighton, Kevin; Newman, Caroline; Nicholson, Gareth; Gallagher, Liam; Boos, Christopher J; Mellor, Adrian; Woods, David R; O'Hara, John P

    2018-01-01

    Postural control and joint position sense are essential for safely undertaking leisure and professional activities, particularly at high altitude. We tested whether exposure to a 12-day trek with a gradual ascent to high altitude impairs postural control and joint position sense. This was a repeated measures observational study of 12 military service personnel (28±4 years). Postural control (sway velocity measured by a portable force platform) during standing balance, a Sharpened Romberg Test and knee joint position sense were measured, in England (113m elevation) and at 3 research camps (3619m, 4600m and 5140m) on a 12-day high altitude trek in the Dhaulagiri region of Nepal. Pulse oximetry, and Lake Louise scores were also recorded on the morning and evening of each trek day. Data were compared between altitudes and relationships between pulse oximetry, Lake Louise score, and sway velocity were explored. Total sway velocity during standing balance with eyes open (p = 0.003, d = 1.9) and during Sharpened Romberg test with eyes open (p = 0.007, d = 1.6) was significantly greater at altitudes of 3619m and 5140m when compared with sea level. Anterior-posterior sway velocity during standing balance with eyes open was also significantly greater at altitudes of 3619m and 5140m when compared with sea level (p = 0.001, d = 1.9). Knee joint position sense was not altered at higher altitudes. There were no significant correlations between Lake Louise scores, pulse oximetry and postural sway. Despite a gradual ascent profile, exposure to 3619 m was associated with impairments in postural control without impairment in knee joint position sense. Importantly, these impairments did not worsen at higher altitudes of 4600 m or 5140 m. The present findings should be considered during future trekking expeditions when developing training strategies targeted to manage impairments in postural control that occur with increasing altitude.

  6. Long-Term Intermittent Exposure to High Altitude Elevates Asymmetric Dimethylarginine in First Exposed Young Adults.

    Science.gov (United States)

    Lüneburg, Nicole; Siques, Patricia; Brito, Julio; De La Cruz, Juan José; León-Velarde, Fabiola; Hannemann, Juliane; Ibanez, Cristian; Böger, Rainer H

    2017-09-01

    Lüneburg, Nicole, Patricia Siques, Julio Brito, Juan José De La Cruz, Fabiola León-Velarde, Juliane Hannemann, Cristian Ibanez, and Rainer Böger. Long-term intermittent exposure to high altitude elevates asymmetric dimethylarginine in first exposed young adults. High Alt Med Biol. 18:226-233, 2017.-Hypoxia-induced dysregulation of pulmonary and cerebral circulation may be related to an impaired nitric oxide (NO) pathway. We investigated the effect of chronic intermittent hypobaric hypoxia (CIH) on metabolites of the NO pathway. We measured asymmetric and symmetric dimethylarginine (ADMA and SDMA) and monomethyl-L-arginine (L-NMMA) and assessed their associations with acclimatization in male draftees (n = 72) undergoing CIH shifts at altitude (3550 m) during 3 months. Sixteen Andean natives living at altitude (3675 m) (chronic hypobaric hypoxia [CH]) were included for comparison. In CIH, ADMA and L-NMMA plasma concentrations increased from 1.14 ± 0.04 to 1.95 ± 0.09 μmol/L (mean ± SE) and from 0.22 ± 0.07 to 0.39 ± 0.03 μmol/L, respectively, (p < 0.001 for both) after 3 months, whereas SDMA did not change. The concentrations of ADMA and L-NMMA were higher in CH (3.48 ± 0.07, 0.53 ± 0.08 μmol/L; p < 0.001) as compared with CIH. In both CIH and CH, ADMA correlated with hematocrit (r 2  = 0.07, p < 0.05; r 2  = 0.26; p < 0.01). In CIH, an association of ADMA levels with poor acclimatization status was observed. We conclude that the endogenous NO synthase inhibitors, ADMA and L-NMMA, are elevated in hypoxia. This may contribute to impaired NO production at altitude and may also be predictive of altitude-associated health impairment.

  7. Four Weeks of Classical Altitude Training Increases Resting Metabolic Rate in Highly Trained Middle-Distance Runners.

    Science.gov (United States)

    Woods, Amy L; Sharma, Avish P; Garvican-Lewis, Laura A; Saunders, Philo U; Rice, Anthony J; Thompson, Kevin G

    2017-02-01

    High altitude exposure can increase resting metabolic rate (RMR) and induce weight loss in obese populations, but there is a lack of research regarding RMR in athletes at moderate elevations common to endurance training camps. The present study aimed to determine whether 4 weeks of classical altitude training affects RMR in middle-distance runners. Ten highly trained athletes were recruited for 4 weeks of endurance training undertaking identical programs at either 2200m in Flagstaff, Arizona (ALT, n = 5) or 600m in Canberra, Australia (CON, n = 5). RMR, anthropometry, energy intake, and hemoglobin mass (Hb mass ) were assessed pre- and posttraining. Weekly run distance during the training block was: ALT 96.8 ± 18.3km; CON 103.1 ± 5.6km. A significant interaction for Time*Group was observed for absolute (kJ.day -1 ) (F-statistic, p-value: F (1,8) =13.890, p = .01) and relative RMR (F (1,8) =653.453, p = .003) POST-training. No significant changes in anthropometry were observed in either group. Energy intake was unchanged (mean ± SD of difference, ALT: 195 ± 3921kJ, p = .25; CON: 836 ± 7535kJ, p = .75). A significant main effect for time was demonstrated for total Hb mass (g) (F (1,8) =13.380, p = .01), but no significant interactions were observed for either variable [Total Hb mass (g): F (1,8) =1.706, p = .23; Relative Hb mass (g.kg -1 ): F (1,8) =0.609, p = .46]. These novel findings have important practical application to endurance athletes routinely training at moderate altitude, and those seeking to optimize energy management without compromising training adaptation. Altitude exposure may increase RMR and enhance training adaptation,. During training camps at moderate altitude, an increased energy intake is likely required to support an increased RMR and provide sufficient energy for training and performance.

  8. A randomly-controlled study on the cardiac function at the early stage of return to the plains after short-term exposure to high altitude.

    Directory of Open Access Journals (Sweden)

    Qiquan Zhou

    Full Text Available High altitude acclimatization and adaptation mechanisms have been well clarified, however, high altitude de-adaptation mechanism remains unclear. In this study, we conducted a controlled study on cardiac functions in 96 healthy young male who rapidly entered the high altitude (3700 m and returned to the plains (1500 m after 50 days. Ninety eight healthy male who remained at low altitude were recruited as control group. The mean pulmonary arterial pressure (mPAP, left ventricular ejection fraction (LVEF, left ventricular fraction shortening (LVFS, cardiac function index (Tei index were tested. Levels of serum creatine kinase isoform MB (CK-MB, lactate dehydrogenase isoenzyme-1 (LDH-1, endothelin-1 (ET-1, nitrogen oxide (NO, serum hypoxia-inducible factor-1α (HIF-1α, 8-iso-prostaglandin F(2α (8-iso PGF(2α, superoxide dismutase (SOD and malonaldehyde (MDA were measured at an altitude of 3700 m and 1500 m respectively. The results showed that after short-term exposure to high altitude mPAP and Tei index increased significantly, while LVEF and LVFS decreased significantly. These changes were positively correlated with altitude. On the 15(th day after the subjects returned to low altitude, mPAP, LVEF and LVFS levels returned to the same level as those of the control subjects, but the Tei index in the returned subjects was still significantly higher than that in the control subjects (P<0.01. We also found that changes in Tei index was positively correlated with mPAP, ET-1, HIF-1α and 8-iso PGF(2α levels, and negatively correlated with the level of NO, LVEF, LVFS, CK-MB and LDH-1. These findings suggest that cardiac function de-adapts when returning to the plains after short-term exposure to high altitude and the function recovery takes a relatively long time.

  9. Galling Insects of the Brazilian Páramos: Species Richness and Composition Along High-Altitude Grasslands.

    Science.gov (United States)

    Coelho, Marcel S; Carneiro, Marco Antônio Alves; Branco, Cristina A; Borges, Rafael Augusto Xavier; Fernandes, G Wilson

    2017-12-08

    In this work, we investigated the factors that determine the distribution of galling insects in high-altitude grasslands, locally called 'campos de altitude' of Mantiqueira Range and tested whether 1) richness of galling insects decreases with altitude, 2) galling insect richness increases with plant richness, 3) variation in galling insect diversity is predominantly a consequence of its β component, and 4) turnover is the main mechanism driving the beta diversity of both galling insects and plants. Galling insect richness did not exhibit a negative relationship with altitude, but it did increase with plant richness. The additive partition of regional richness (γ) into its local and beta components showed that local diversity (α) of galling insects and plants was relatively low in relation to regional diversity; the β component incorporated most of the regional diversity. This pattern was also found in the multiscale analysis of the additive partition for galling insects and plants. The beta diversity of galling insects and plants was driven predominantly by the process of turnover and minimally by nesting. The results reported here point out that the spatial distribution of galling insects is best explained by historical factors, such as the distribution of genera and species of key host plants, as well as their relation to habitat, than ecological effects such as hygrothermal stress - here represented by altitude. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  10. Ecophysiological Responses of Three Tree Species to a High-Altitude Environment in the Southeastern Tibetan Plateau

    Directory of Open Access Journals (Sweden)

    Jirui Gong

    2018-01-01

    Full Text Available This paper measured the ecophysiological responses of Populus cathayana Rehd., Salix longistamina C. Wang et P. Y. Fu., and Ulmus pumila L. to high altitude in the Tibetan Plateau based on changes in water relations, gas exchange, and chlorophyll fluorescence. P. cathayana and U. pumila have higher survival rates than S. longistamina, but the latter has highest biomass. S. longistamina has higher water-use efficiency (WUE, lower transpiration rates (E, higher water potential (Ψ, highest light saturation point (LSP and higher photosystem II (PSII photochemistry efficiency (Fv’/Fm’ and non-photochemistry quenching (NPQ than the other species, and is thus adapted to its habitat for afforestation. U. pumila has lower E, light compensation point (LCP, dark respiration (Rd, Fv’/Fm’ and electron transport rate (ETR, with higher Ψ, apparent quantum yield (AQY, net photosynthetic rate (Pn and non-photochemical quenching (NPQ, which helps it maintain water balance and utilize weak light to survive at high altitude. Relative low WUE, Ψ, Rd, NPQ, with high E, Pn, Fv’/Fm’ and biomass, imply that P. cathayana is more suitable for shelterbelt forests than for a semi-arid habitat. These three species can adapt to high-altitude conditions by different physiological mechanisms and morphological characteristics, which can provide a theoretical basis for afforestation and forest management in the Qinghai Tibetan Plateau.

  11. Cerebral pressure-flow relationship in lowlanders and natives at high altitude.

    Science.gov (United States)

    Smirl, Jonathan D; Lucas, Samuel J E; Lewis, Nia C S; duManoir, Gregory R; Dumanior, Gregory R; Smith, Kurt J; Bakker, Akke; Basnyat, Aperna S; Ainslie, Philip N

    2014-02-01

    We investigated if dynamic cerebral pressure-flow relationships in lowlanders are altered at high altitude (HA), differ in HA natives and after return to sea level (SL). Lowlanders were tested at SL (n=16), arrival to 5,050 m, after 2-week acclimatization (with and without end-tidal PO2 normalization), and upon SL return. High-altitude natives (n=16) were tested at 5,050 m. Testing sessions involved resting spontaneous and driven (squat-stand maneuvers at very low (VLF, 0.05 Hz) and low (LF, 0.10 Hz) frequencies) measures to maximize blood pressure (BP) variability and improve assessment of the pressure-flow relationship using transfer function analysis (TFA). Blood flow velocity was assessed in the middle (MCAv) and posterior (PCAv) cerebral arteries. Spontaneous VLF and LF phases were reduced and coherence was elevated with acclimatization to HA (Pflow coupling. However, when BP was driven, both the frequency- and time-domain metrics were unaltered and comparable with HA natives. Acute mountain sickness was unrelated to TFA metrics. In conclusion, the driven cerebral pressure-flow relationship (in both frequency and time domains) is unaltered at 5,050 m in lowlanders and HA natives. Our findings indicate that spontaneous changes in TFA metrics do not necessarily reflect physiologically important alterations in the capacity of the brain to regulate BP.

  12. Characteristics of high altitude oxygen ion energization and outflow as observed by Cluster: a statistical study

    Directory of Open Access Journals (Sweden)

    H. Nilsson

    2006-05-01

    Full Text Available The results of a statistical study of oxygen ion outflow using Cluster data obtained at high altitude above the polar cap is reported. Moment data for both hydrogen ions (H+ and oxygen ions (O+ from 3 years (2001-2003 of spring orbits (January to May have been used. The altitudes covered were mainly in the range 5–12 RE geocentric distance. It was found that O+ is significantly transversely energized at high altitudes, indicated both by high perpendicular temperatures for low magnetic field values as well as by a tendency towards higher perpendicular than parallel temperature distributions for the highest observed temperatures. The O+ parallel bulk velocity increases with altitude in particular for the lowest observed altitude intervals. O+ parallel bulk velocities in excess of 60 km s-1 were found mainly at higher altitudes corresponding to magnetic field strengths of less than 100 nT. For the highest observed parallel bulk velocities of O+ the thermal velocity exceeds the bulk velocity, indicating that the beam-like character of the distribution is lost. The parallel bulk velocity of the H+ and O+ was found to typically be close to the same throughout the observation interval when the H+ bulk velocity was calculated for all pitch-angles. When the H+ bulk velocity was calculated for upward moving particles only the H+ parallel bulk velocity was typically higher than that of O+. The parallel bulk velocity is close to the same for a wide range of relative abundance of the two ion species, including when the O+ ions dominates. The thermal velocity of O+ was always well below that of H+. Thus perpendicular energization that is more effective for O+ takes place, but this is not enough to explain the close to similar parallel velocities. Further

  13. Development and testing of airfoils for high-altitude aircraft

    Science.gov (United States)

    Drela, Mark (Principal Investigator)

    1996-01-01

    Specific tasks included airfoil design; study of airfoil constraints on pullout maneuver; selection of tail airfoils; examination of wing twist; test section instrumentation and layout; and integrated airfoil/heat-exchanger tests. In the course of designing the airfoil, specifically for the APEX test vehicle, extensive studies were made over the Mach and Reynolds number ranges of interest. It is intended to be representative of airfoils required for lightweight aircraft operating at extreme altitudes, which is the primary research objective of the APEX program. Also considered were thickness, pitching moment, and off-design behavior. The maximum ceiling parameter M(exp 2)C(sub L) value achievable by the Apex-16 airfoil was found to be a strong constraint on the pullout maneuver. The NACA 1410 and 2410 airfoils (inverted) were identified as good candidates for the tail, with predictable behavior at low Reynolds numbers and good tolerance to flap deflections. With regards to wing twist, it was decided that a simple flat wing was a reasonable compromise. The test section instrumentation consisted of surface pressure taps, wake rakes, surface-mounted microphones, and skin-friction gauges. Also, a modest wind tunnel test was performed for an integrated airfoil/heat-exchanger configuration, which is currently on Aurora's 'Theseus' aircraft. Although not directly related to the APEX tests, the aerodynamics or heat exchangers has been identified as a crucial aspect of designing high-altitude aircraft and hence is relevant to the ERAST program.

  14. IceCube: Particle Astrophysics with High Energy Neutrinos

    CERN Multimedia

    Université de Genève

    2012-01-01

    GENEVA UNIVERSITY École de physique Département de physique nucléaire et corspusculaire 24, quai Ernest-Ansermet 1211 Genève 4 Tél.: (022) 379 62 73 Fax: (022) 379 69 92 Monday 7 May 2012 17h. - Ecole de Physique, Auditoire Stueckelberg IceCube: Particle Astrophysics with High Energy Neutrinos Prof. Francis Halzen / University of Wisconsin, Madison Construction and commissioning of the cubic-kilometer IceCube neutrino detector and its low energy extension DeepCore have been completed. The instrument detects neutrinos over a wide energy range: from 10 GeV atmospheric neutrinos to 1010 GeV cosmogenic neutrinos. We will discuss initial results based on a subsample of the ~100,000 neutrino events recorded during construction. We will emphasize the first measurement of the high-energy atmospheric neutrino spectrum, the search for the still enigmatic sources of the Galactic and extragalactic cosmic rays and for the particle nature of dark matter. Une ve...

  15. A High-Resolution Continuous Flow Analysis System for Polar Ice Cores

    DEFF Research Database (Denmark)

    Dallmayr, Remi; Goto-Azuma, Kumiko; Kjær, Helle Astrid

    2016-01-01

    of Polar Research (NIPR) in Tokyo. The system allows the continuous analysis of stable water isotopes and electrical conductivity, as well as the collection of discrete samples from both inner and outer parts of the core. This CFA system was designed to have sufficiently high temporal resolution to detect...... signals of abrupt climate change in deep polar ice cores. To test its performance, we used the system to analyze different climate intervals in ice drilled at the NEEM (North Greenland Eemian Ice Drilling) site, Greenland. The quality of our continuous measurement of stable water isotopes has been......In recent decades, the development of continuous flow analysis (CFA) technology for ice core analysis has enabled greater sample throughput and greater depth resolution compared with the classic discrete sampling technique. We developed the first Japanese CFA system at the National Institute...

  16. An Undergraduate-Built Prototype Altitude Determination System (PADS) for High Altitude Research Balloons.

    Science.gov (United States)

    Verner, E.; Bruhweiler, F. C.; Abot, J.; Casarotto, V.; Dichoso, J.; Doody, E.; Esteves, F.; Morsch Filho, E.; Gonteski, D.; Lamos, M.; Leo, A.; Mulder, N.; Matubara, F.; Schramm, P.; Silva, R.; Quisberth, J.; Uritsky, G.; Kogut, A.; Lowe, L.; Mirel, P.; Lazear, J.

    2014-12-01

    In this project a multi-disciplinary undergraduate team from CUA, comprising majors in Physics, Mechanical Engineering, Electrical Engineering, and Biology, design, build, test, fly, and analyze the data from a prototype attitude determination system (PADS). The goal of the experiment is to determine if an inexpensive attitude determination system could be built for high altitude research balloons using MEMS gyros. PADS is a NASA funded project, built by students with the cooperation of CUA faculty, Verner, Bruhweiler, and Abot, along with the contributed expertise of researchers and engineers at NASA/GSFC, Kogut, Lowe, Mirel, and Lazear. The project was initiated through a course taught in CUA's School of Engineering, which was followed by a devoted effort by students during the summer of 2014. The project is an experiment to use 18 MEMS gyros, similar to those used in many smartphones, to produce an averaged positional error signal that could be compared with the motion of the fixed optical system as recorded through a string of optical images of stellar fields to be stored on a hard drive flown with the experiment. The optical system, camera microprocessor, and hard drive are enclosed in a pressure vessel, which maintains approximately atmospheric pressure throughout the balloon flight. The experiment uses multiple microprocessors to control the camera exposures, record gyro data, and provide thermal control. CUA students also participated in NASA-led design reviews. Four students traveled to NASA's Columbia Scientific Balloon Facility in Palestine, Texas to integrate PADS into a large balloon gondola containing other experiments, before being shipped, then launched in mid-August at Ft. Sumner, New Mexico. The payload is to fly at a float altitude of 40-45,000 m, and the flight last approximately 15 hours. The payload is to return to earth by parachute and the retrieved data are to be analyzed by CUA undergraduates. A description of the instrument is presented

  17. High geothermal heat flux measured below the West Antarctic Ice Sheet.

    Science.gov (United States)

    Fisher, Andrew T; Mankoff, Kenneth D; Tulaczyk, Slawek M; Tyler, Scott W; Foley, Neil

    2015-07-01

    The geothermal heat flux is a critical thermal boundary condition that influences the melting, flow, and mass balance of ice sheets, but measurements of this parameter are difficult to make in ice-covered regions. We report the first direct measurement of geothermal heat flux into the base of the West Antarctic Ice Sheet (WAIS), below Subglacial Lake Whillans, determined from the thermal gradient and the thermal conductivity of sediment under the lake. The heat flux at this site is 285 ± 80 mW/m(2), significantly higher than the continental and regional averages estimated for this site using regional geophysical and glaciological models. Independent temperature measurements in the ice indicate an upward heat flux through the WAIS of 105 ± 13 mW/m(2). The difference between these heat flux values could contribute to basal melting and/or be advected from Subglacial Lake Whillans by flowing water. The high geothermal heat flux may help to explain why ice streams and subglacial lakes are so abundant and dynamic in this region.

  18. High geothermal heat flux measured below the West Antarctic Ice Sheet

    Science.gov (United States)

    Fisher, Andrew T.; Mankoff, Kenneth D.; Tulaczyk, Slawek M.; Tyler, Scott W.; Foley, Neil

    2015-01-01

    The geothermal heat flux is a critical thermal boundary condition that influences the melting, flow, and mass balance of ice sheets, but measurements of this parameter are difficult to make in ice-covered regions. We report the first direct measurement of geothermal heat flux into the base of the West Antarctic Ice Sheet (WAIS), below Subglacial Lake Whillans, determined from the thermal gradient and the thermal conductivity of sediment under the lake. The heat flux at this site is 285 ± 80 mW/m2, significantly higher than the continental and regional averages estimated for this site using regional geophysical and glaciological models. Independent temperature measurements in the ice indicate an upward heat flux through the WAIS of 105 ± 13 mW/m2. The difference between these heat flux values could contribute to basal melting and/or be advected from Subglacial Lake Whillans by flowing water. The high geothermal heat flux may help to explain why ice streams and subglacial lakes are so abundant and dynamic in this region. PMID:26601210

  19. Classical altitude training.

    Science.gov (United States)

    Friedmann-Bette, B

    2008-08-01

    For more than 40 years, the effects of classical altitude training on sea-level performance have been the subject of many scientific investigations in individual endurance sports. To our knowledge, no studies have been performed in team sports like football. Two well-controlled studies showed that living and training at an altitude of >or=1800-2700 m for 3-4 weeks is superior to equivalent training at sea level in well-trained athletes. Most of the controlled studies with elite athletes did not reveal such an effect. However, the results of some uncontrolled studies indicate that sea-level performance might be enhanced after altitude training also in elite athletes. Whether hypoxia provides an additional stimulus for muscular adaptation, when training is performed with equal intensity compared with sea-level training is not known. There is some evidence for an augmentation of total hemoglobin mass after classical altitude training with duration >or=3 weeks at an altitude >or=2000 m due to altitude acclimatization. Considerable individual variation is observed in the erythropoietic response to hypoxia and in the hypoxia-induced reduction of aerobic performance capacity during training at altitude, both of which are thought to contribute to inter-individual variation in the improvement of sea-level performance after altitude training.

  20. Reducing uncertainty in high-resolution sea ice models.

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, Kara J.; Bochev, Pavel Blagoveston

    2013-07-01

    Arctic sea ice is an important component of the global climate system, reflecting a significant amount of solar radiation, insulating the ocean from the atmosphere and influencing ocean circulation by modifying the salinity of the upper ocean. The thickness and extent of Arctic sea ice have shown a significant decline in recent decades with implications for global climate as well as regional geopolitics. Increasing interest in exploration as well as climate feedback effects make predictive mathematical modeling of sea ice a task of tremendous practical import. Satellite data obtained over the last few decades have provided a wealth of information on sea ice motion and deformation. The data clearly show that ice deformation is focused along narrow linear features and this type of deformation is not well-represented in existing models. To improve sea ice dynamics we have incorporated an anisotropic rheology into the Los Alamos National Laboratory global sea ice model, CICE. Sensitivity analyses were performed using the Design Analysis Kit for Optimization and Terascale Applications (DAKOTA) to determine the impact of material parameters on sea ice response functions. Two material strength parameters that exhibited the most significant impact on responses were further analyzed to evaluate their influence on quantitative comparisons between model output and data. The sensitivity analysis along with ten year model runs indicate that while the anisotropic rheology provides some benefit in velocity predictions, additional improvements are required to make this material model a viable alternative for global sea ice simulations.

  1. Dietary Recommendations for Cyclists during Altitude Training.

    Science.gov (United States)

    Michalczyk, Małgorzata; Czuba, Miłosz; Zydek, Grzegorz; Zając, Adam; Langfort, Józef

    2016-06-18

    The concept of altitude or hypoxic training is a common practice in cycling. However, several strategies for training regimens have been proposed, like "live high, train high" (LH-TH), "live high, train low" (LH-TL) or "intermittent hypoxic training" (IHT). Each of them combines the effect of acclimatization and different training protocols that require specific nutrition. An appropriate nutrition strategy and adequate hydration can help athletes achieve their fitness and performance goals in this unfriendly environment. In this review, the physiological stress of altitude exposure and training will be discussed, with specific nutrition recommendations for athletes training under such conditions. However, there is little research about the nutrition demands of athletes who train at moderate altitude. Our review considers energetic demands and body mass or body composition changes due to altitude training, including respiratory and urinary water loss under these conditions. Carbohydrate intake recommendations and hydration status are discussed in detail, while iron storage and metabolism is also considered. Last, but not least the risk of increased oxidative stress under hypoxic conditions and antioxidant supplementation suggestions are presented.

  2. Women at Altitude: Effects of Menstrual Cycle Phase and Alpha-Adrenergic Blockade on High Altitude Acclimatization

    National Research Council Canada - National Science Library

    Moore, Lorna

    1998-01-01

    .... Results indicated that the effects of the menstrual cycle were modest. In year 2, we evaluated the safety and efficacy of administering an a-adrenergic blocker and made selected observations during a brief exposure to an altitude of 4300 m...

  3. Structures of high and low density amorphous ice by neutron diffraction

    International Nuclear Information System (INIS)

    Finney, J.L.; Hallbrucker, A.; Kohl, I.; Soper, A.K.; Bowron, D.T.

    2002-01-01

    Neutron diffraction with isotope substitution is used to determine the structures of high (HDA) and low (LDA) density amorphous ice. Both 'phases' are fully hydrogen bonded, tetrahedral networks, with local order similarities between LDA and ice Ih, and HDA and liquid water. Moving from HDA, through liquid water and LDA to ice Ih, the second shell radial order increases at the expense of spatial order. This is linked to a fifth first neighbor 'interstitial' that restricts the orientations of first shell waters. This 'lynch pin' molecule which keeps the HDA structure intact has implications for the nature of the HDA-LDA transition that bear on the current metastable water debate

  4. High altitude headache and acute mountain sickness at moderate elevations in a military population during battalion-level training exercises.

    Science.gov (United States)

    Norris, Jacob N; Viirre, Erik; Aralis, Hilary; Sracic, Michael K; Thomas, Darren; Gertsch, Jeffery H

    2012-08-01

    Few studies have evaluated high altitude headache (HAH) and acute mountain sickness (AMS) in military populations training at moderate (1,500-2,500 m) to high altitudes (>2,500 m). In the current study, researchers interviewed active duty personnel training at Marine Corps Mountain Warfare Training Center. Participants were asked about HAH and AMS symptoms, potential risk factors, and medications used. In a sample of 192 U.S. Navy and Marine Corps personnel, 14.6% reported AMS (Lake Louise Criteria > or = 3) and 28.6% reported HAH. Dehydration and recent arrival at altitude (defined as data collected on days 2-3) were significantly associated with AMS; decreased sleep allowance was significantly associated with HAH. Although ibuprofen/Motrin users were more likely to screen positive for AMS, among AMS-positive participants, ibuprofen/Motrin users had decreased likelihood of reporting robust AMS relative to non-ibuprofen/Motrin users (p altitude. Further, ibuprofen/Motrin may be a reasonable treatment for the symptoms of AMS and HAH, although further study is warranted.

  5. WCDMA Uplink Interference Assessment from Multiple High Altitude Platform Configurations

    Directory of Open Access Journals (Sweden)

    A. Mohammed

    2008-06-01

    Full Text Available We investigate the possibility of multiple high altitude platform (HAP coverage of a common cell area using a wideband code division multiple access (WCDMA system. In particular, we study the uplink system performance of the system. The results show that depending on the traffic demand and the type of service used, there is a possibility of deploying 3–6 HAPs covering the same cell area. The results also show the effect of cell radius on performance and the position of the multiple HAP base stations which give the worst performance.

  6. Oxygen transfer properties and dimensions of red blood cells in high-altitude camelids, dromedary camel and goat.

    Science.gov (United States)

    Yamaguchi, K; Jürgens, K D; Bartels, H; Piiper, J

    1987-01-01

    To estimate the advantage of the small red blood cells (RBC) of high-altitude camelids for O2 transfer, the kinetics of O2 uptake into and release from the RBC obtained from llama, vicuña and alpaca were investigated at 37 degrees C with a stopped-flow technique. O2 transfer conductance of RBC (G) was estimated from the rate of O2 saturation change and the corresponding O2 pressure difference between medium and hemoglobin. For comparison, O2 kinetics for the RBC of a low-altitude camelid (dromedary camel) and the pygmy goat were determined and previously measured values for human RBC were used. O2 transfer of RBC was found to be strongly influenced by extracellular diffusion, except with O2 release into dithionite solutions of sufficiently high concentration (greater than 30 mM). The G values measured in these 'standard' conditions, Gst (in mmol X min-1 X Torr-1 X (ml RBC)-1) were: high-altitude camelids, 0.58 (averaged for llama, alpaca and vicuña since there were no significant interspecific differences); camel 0.42; goat, 0.42; man, 0.39. The differences can in part be attributed to expected effects of the size and shape of the RBC (volume, surface area, mean thickness), as well as to the intracellular O2 diffusivity which depends on the concentration of cellular hemoglobin. The high Gst of RBC of high-altitude camelids may be considered to enhance O2 transfer in lungs and tissues. But the O2 transfer conductance of blood, theta, equal to Gst multiplied by hematocrit (in mmol X min-1 X Torr-1 X (ml blood)-1), was only slightly higher as compared to other species: 0.20 (llama, alpaca, vicuña), 0.14 (camel), 0.18 (goat), 0.17 (man).

  7. Climate warming and the recent treeline shift in the European alps: the role of geomorphological factors in high-altitude sites.

    Science.gov (United States)

    Leonelli, Giovanni; Pelfini, Manuela; di Cella, Umberto Morra; Garavaglia, Valentina

    2011-05-01

    Global warming and the stronger regional temperature trends recently recorded over the European Alps have triggered several biological and physical dynamics in high-altitude environments. We defined the present treeline altitude in three valleys of a region in the western Italian Alps and reconstructed the past treeline position for the last three centuries in a nearly undisturbed site by means of a dendrochronological approach. We found that the treeline altitude in this region is mainly controlled by human impacts and geomorphological factors. The reconstruction of the altitudinal dynamics at the study site reveals that the treeline shifted upwards of 115 m over the period 1901-2000, reaching the altitude of 2505 m in 2000 and 2515 m in 2008. The recent treeline shift and the acceleration of tree colonization rates in the alpine belt can be mainly ascribed to the climatic input. However, we point out the increasing role of geomorphological factors in controlling the future treeline position and colonization patterns in high mountains.

  8. Hypoxia triggers high-altitude headache with migraine features: A prospective trial.

    Science.gov (United States)

    Broessner, Gregor; Rohregger, Johanna; Wille, Maria; Lackner, Peter; Ndayisaba, Jean-Pierre; Burtscher, Martin

    2016-07-01

    Given the high prevalence and clinical impact of high-altitude headache (HAH), a better understanding of risk factors and headache characteristics may give new insights into the understanding of hypoxia being a trigger for HAH or even migraine attacks. In this prospective trial, we simulated high altitude (4500 m) by controlled normobaric hypoxia (FiO2 = 12.6%) to investigate acute mountain sickness (AMS) and headache characteristics. Clinical symptoms of AMS according to the Lake Louise Scoring system (LLS) were recorded before and after six and 12 hours in hypoxia. O2 saturation was measured using pulse oximetry at the respective time points. History of primary headache, especially episodic or chronic migraine, was a strict exclusion criterion. In total 77 volunteers (43 (55.8%) males, 34 (44.2%) females) were enrolled in this study. Sixty-three (81.18%) and 40 (71.4%) participants developed headache at six or 12 hours, respectively, with height and SpO2 being significantly different between headache groups at six hours (p headache development (p headache according to the International Classification of Headache Disorders (ICHD-3 beta) in n = 5 (8%) or n = 6 (15%), at six and 12 hours, respectively. Normobaric hypoxia is a trigger for HAH and migraine-like headache attacks even in healthy volunteers without any history of migraine. Our study confirms the pivotal role of hypoxia in the development of AMS and beyond that suggests hypoxia may be involved in migraine pathophysiology. © International Headache Society 2015.

  9. Preparation for Scaling Studies of Ice-Crystal Icing at the NRC Research Altitude Test Facility

    Science.gov (United States)

    Struk, Peter M.; Bencic, Timothy J.; Tsao, Jen-Ching; Fuleki, Dan; Knezevici, Daniel C.

    2013-01-01

    This paper describes experiments conducted at the National Research Council (NRC) of Canadas Research Altitiude Test Facility between March 26 and April 11, 2012. The tests, conducted collaboratively between NASA and NRC, focus on three key aspects in preparation for later scaling work to be conducted with a NACA 0012 airfoil model in the NRC Cascade rig: (1) cloud characterization, (2) scaling model development, and (3) ice-shape profile measurements. Regarding cloud characterization, the experiments focus on particle spectra measurements using two shadowgraphy methods, cloud uniformity via particle scattering from a laser sheet, and characterization of the SEA Multi-Element probe. Overviews of each aspect as well as detailed information on the diagnostic method are presented. Select results from the measurements and interpretation are presented which will help guide future work.

  10. Trends and solar cycle effects in mesospheric ice clouds

    Science.gov (United States)

    Lübken, Franz-Josef; Berger, Uwe; Fiedler, Jens; Baumgarten, Gerd; Gerding, Michael

    Lidar observations of mesospheric ice layers (noctilucent clouds, NLC) are now available since 12 years which allows to study solar cycle effects on NLC parameters such as altitudes, bright-ness, and occurrence rates. We present observations from our lidar stations in Kuehlungsborn (54N) and ALOMAR (69N). Different from general expectations the mean layer characteris-tics at ALOMAR do not show a persistent anti-correlation with solar cycle. Although a nice anti-correlation of Ly-alpha and occurrence rates is detected in the first half of the solar cycle, occurrence rates decreased with decreasing solar activity thereafter. Interestingly, in summer 2009 record high NLC parameters were detected as expected in solar minimum conditions. The morphology of NLC suggests that other processes except solar radiation may affect NLC. We have recently applied our LIMA model to study in detail the solar cycle effects on tempera-tures and water vapor concentration the middle atmosphere and its subsequent influence on mesospheric ice clouds. Furthermore, lower atmosphere effects are implicitly included because LIMA nudges to the conditions in the troposphere and lower stratosphere. We compare LIMA results regarding solar cycle effects on temperatures and ice layers with observations at ALO-MAR as well as satellite borne measurements. We will also present LIMA results regarding the latitude variation of solar cycle and trends, including a comparison of northern and southern hemisphere. We have adapted the observation conditions from SBUV (wavelength and scatter-ing angle) in LIMA for a detailed comparison with long term observations of ice clouds from satellites.

  11. An appraisal of precipitation distribution in the high-altitude catchments of the Indus basin.

    Science.gov (United States)

    Dahri, Zakir Hussain; Ludwig, Fulco; Moors, Eddy; Ahmad, Bashir; Khan, Asif; Kabat, Pavel

    2016-04-01

    Scarcity of in-situ observations coupled with high orographic influences has prevented a comprehensive assessment of precipitation distribution in the high-altitude catchments of Indus basin. Available data are generally fragmented and scattered with different organizations and mostly cover the valleys. Here, we combine most of the available station data with the indirect precipitation estimates at the accumulation zones of major glaciers to analyse altitudinal dependency of precipitation in the high-altitude Indus basin. The available observations signified the importance of orography in each sub-hydrological basin but could not infer an accurate distribution of precipitation with altitude. We used Kriging with External Drift (KED) interpolation scheme with elevation as a predictor to appraise spatiotemporal distribution of mean monthly, seasonal and annual precipitation for the period of 1998-2012. The KED-based annual precipitation estimates are verified by the corresponding basin-wide observed specific runoffs, which show good agreement. In contrast to earlier studies, our estimates reveal substantially higher precipitation in most of the sub-basins indicating two distinct rainfall maxima; 1st along southern and lower most slopes of Chenab, Jhelum, Indus main and Swat basins, and 2nd around north-west corner of Shyok basin in the central Karakoram. The study demonstrated that the selected gridded precipitation products covering this region are prone to significant errors. In terms of quantitative estimates, ERA-Interim is relatively close to the observations followed by WFDEI and TRMM, while APHRODITE gives highly underestimated precipitation estimates in the study area. Basin-wide seasonal and annual correction factors introduced for each gridded dataset can be useful for lumped hydrological modelling studies, while the estimated precipitation distribution can serve as a basis for bias correction of any gridded precipitation products for the study area

  12. Variations in airborne bacterial communities at high altitudes over the Noto Peninsula (Japan) in response to Asian dust events

    Science.gov (United States)

    Maki, Teruya; Hara, Kazutaka; Iwata, Ayumu; Lee, Kevin C.; Kawai, Kei; Kai, Kenji; Kobayashi, Fumihisa; Pointing, Stephen B.; Archer, Stephen; Hasegawa, Hiroshi; Iwasaka, Yasunobu

    2017-10-01

    Aerosol particles, including airborne microorganisms, are transported through the free troposphere from the Asian continental area to the downwind area in East Asia and can influence climate changes, ecosystem dynamics, and human health. However, the variations present in airborne bacterial communities in the free troposphere over downwind areas are poorly understood, and there are few studies that provide an in-depth examination of the effects of long-range transport of aerosols (natural and anthropogenic particles) on bacterial variations. In this study, the vertical distributions of airborne bacterial communities at high altitudes were investigated and the bacterial variations were compared between dust events and non-dust events.Aerosols were collected at three altitudes from ground level to the free troposphere (upper level: 3000 or 2500 m; middle level: 1200 or 500 m; and low level: 10 m) during Asian dust events and non-dust events over the Noto Peninsula, Japan, where westerly winds carry aerosols from the Asian continental areas. During Asian dust events, air masses at high altitudes were transported from the Asian continental area by westerly winds, and laser imaging detection and ranging (lidar) data indicated high concentrations of non-spherical particles, suggesting that dust-sand particles were transported from the central desert regions of Asia. The air samples collected during the dust events contained 10-100 times higher concentrations of microscopic fluorescent particles and optical particle counter (OPC) measured particles than in non-dust events. The air masses of non-dust events contained lower amounts of dust-sand particles. Additionally, some air samples showed relatively high levels of black carbon, which were likely transported from the Asian continental coasts. Moreover, during the dust events, microbial particles at altitudes of > 1200 m increased to the concentrations ranging from 1. 2 × 106 to 6. 6 × 106 particles m-3. In contrast

  13. Statistical Analyses of High-Resolution Aircraft and Satellite Observations of Sea Ice: Applications for Improving Model Simulations

    Science.gov (United States)

    Farrell, S. L.; Kurtz, N. T.; Richter-Menge, J.; Harbeck, J. P.; Onana, V.

    2012-12-01

    Satellite-derived estimates of ice thickness and observations of ice extent over the last decade point to a downward trend in the basin-scale ice volume of the Arctic Ocean. This loss has broad-ranging impacts on the regional climate and ecosystems, as well as implications for regional infrastructure, marine navigation, national security, and resource exploration. New observational datasets at small spatial and temporal scales are now required to improve our understanding of physical processes occurring within the ice pack and advance parameterizations in the next generation of numerical sea-ice models. High-resolution airborne and satellite observations of the sea ice are now available at meter-scale resolution or better that provide new details on the properties and morphology of the ice pack across basin scales. For example the NASA IceBridge airborne campaign routinely surveys the sea ice of the Arctic and Southern Oceans with an advanced sensor suite including laser and radar altimeters and digital cameras that together provide high-resolution measurements of sea ice freeboard, thickness, snow depth and lead distribution. Here we present statistical analyses of the ice pack primarily derived from the following IceBridge instruments: the Digital Mapping System (DMS), a nadir-looking, high-resolution digital camera; the Airborne Topographic Mapper, a scanning lidar; and the University of Kansas snow radar, a novel instrument designed to estimate snow depth on sea ice. Together these instruments provide data from which a wide range of sea ice properties may be derived. We provide statistics on lead distribution and spacing, lead width and area, floe size and distance between floes, as well as ridge height, frequency and distribution. The goals of this study are to (i) identify unique statistics that can be used to describe the characteristics of specific ice regions, for example first-year/multi-year ice, diffuse ice edge/consolidated ice pack, and convergent

  14. Altitude training improves glycemic control.

    Science.gov (United States)

    Chen, Shu-Man; Lin, Hsueh-Yi; Kuo, Chia-Hua

    2013-08-31

    Under altitude hypoxia condition, energy reliance on anaerobic glycolysis increases to compensate the shortfall caused by reduced fatty acid oxidation. Short-term moderate altitude exposure plus endurance physical activity has been found to improve glucose tolerance (not fasting glucose) in humans, which is associated with the improvement in the whole-body insulin sensitivity. However, most of people cannot accommodate high altitude exposure above 4500 M due to acute mountain sickness and insulin resistance. There is a wide variation among individuals in response to the altitude challenge. In particular, the improvement in glucose tolerance and insulin sensitivity by prolonged altitude hiking activity was not apparent in those individuals with low baseline dehydroepiandrosterone sulfate (DHEA-S) concentration. In rats, exercise training recovery under prolonged hypoxia exposure (14-15% oxygen, 8 h per day for 6 weeks) can also improve insulin sensitivity, secondary to an effective suppression of adiposity. After prolonged hypoxia training, obese abnormality in upregulated baseline levels of AMP-activated protein kinase (AMPK) and AS160 phosphorylation in skeletal muscle can be reversed. In humans, moderate hypoxia increases postprandial blood distribution towards skeletal muscle during a training recovery. This physiological response plays a role in the redistribution of fuel storage among important energy storage sites and may explain its potent effect on the favorable change in body composition. Altitude training can exert strong impact on our metabolic system, and has the potential to be designed as a non-pharmacological or recreational intervention regimen for correcting metabolic syndromes.

  15. Comparative Study of Wing Lift Distribution Analysis for High Altitude Long Endurance (HALE) Unmaned Aerial Vehicle

    Science.gov (United States)

    Silitonga, Faber Y.; Agoes Moelyadi, M.

    2018-04-01

    The development of High Altitude Long Endurance (HALE) Unmanned Aerial Vehicle (UAV) has been emerged for both civil and military purposes. Its ability of operating in high altitude with long endurance is important in supporting maritime applications.Preliminary analysis of HALE UAV lift distribution of the wing presented to give decisive consideration for its early development. Ensuring that the generated lift is enough to compensate its own weight. Therotical approach using Pradtl’s non-linear lifting line theory will be compared with modern numerical approach using Computational Fluid Dynamics (CFD). Results of wing lift distribution calculated from both methods will be compared to study the reliability of it. HALE UAV ITB has high aspect ratio wing and will be analyze at cruise flight condition. The result indicates difference between Non-linear Lifting Line and CFD method.

  16. Effect of altitude on physiological performance: a statistical analysis using results of international football games.

    Science.gov (United States)

    McSharry, Patrick E

    2007-12-22

    To assess the effect of altitude on match results and physiological performance of a large and diverse population of professional athletes. Statistical analysis of international football (soccer) scores and results. FIFA extensive database of 1460 football matches in 10 countries spanning over 100 years. Altitude had a significant (Pnegative impact on physiological performance as revealed through the overall underperformance of low altitude teams when playing against high altitude teams in South America. High altitude teams score more and concede fewer goals with increasing altitude difference. Each additional 1000 m of altitude difference increases the goal difference by about half of a goal. The probability of the home team winning for two teams from the same altitude is 0.537, whereas this rises to 0.825 for a home team with an altitude difference of 3695 m (such as Bolivia v Brazil) and falls to 0.213 when the altitude difference is -3695 m (such as Brazil v Bolivia). Altitude provides a significant advantage for high altitude teams when playing international football games at both low and high altitudes. Lowland teams are unable to acclimatise to high altitude, reducing physiological performance. As physiological performance does not protect against the effect of altitude, better predictors of individual susceptibility to altitude illness would facilitate team selection.

  17. Exercise capacity and selected physiological factors by ancestry and residential altitude

    DEFF Research Database (Denmark)

    Bianba; Berntsen, Sveinung; Andersen, Lars Bo

    2014-01-01

    AIM: Several physiological compensatory mechanisms have enabled Tibetans to live and work at high altitude, including increased ventilation and pulmonary diffusion capacity, both of which serve to increase oxygen transport in the blood. The aim of the present study was to compare exercise capacity...... Tibetans vs. Han Chinese may reflect a better adaptation to life at high altitude. Tibetans at the lower residential altitude of 3700 m demonstrated a better exercise capacity than residents at a higher altitude of 4300 m when measured at their respective residential altitudes. Such altitude- or ancestry...... (maximal power output) and selected physiological factors (arterial oxygen saturation and heart rate at rest and during maximal exercise, resting hemoglobin concentration, and forced vital capacity) in groups of native Tibetan children living at different residential altitudes (3700 vs. 4300 m above sea...

  18. Introduction to altitude/hypoxic training symposium.

    Science.gov (United States)

    Wilber, Randall L

    2007-09-01

    Altitude/hypoxic training has traditionally been an intriguing and controversial area of research and sport performance. This controversial aspect was evident recently in the form of scholarly debates in highly regarded professional journals, as well as the World Anti-Doping Agency's (WADA) consideration of placing "artificially-induced hypoxic conditions" on the 2007 Prohibited List of Substances/Methods. In light of the ongoing controversy surrounding altitude/hypoxic training, this symposium was organized with the following objectives in mind: 1) to examine the primary physiological responses and underlying mechanisms associated with altitude/hypoxic training, including the influence of genetic predisposition; 2) to present evidence supporting the effect of altitude/hypoxic acclimatization on both hematological and nonhematological markers, including erythrocyte volume, skeletal muscle-buffering capacity, hypoxic ventilatory response, and physiological efficiency/economy; 3) to evaluate the efficacy of several contemporary simulated altitude modalities and training strategies, including hypoxic tents, nitrogen apartments, and intermittent hypoxic exposure (IHE) or training, and to address the legal and ethical issues associated with the use of simulated altitude; and 4) to describe different altitude/hypoxic training strategies used by elite-level athletes, including Olympians and military special forces. In addressing these objectives, papers will be presented on the topics of: 1) effect of hypoxic "dose" on physiological responses and sea-level performance (Drs. Benjamin Levine and James Stray-Gundersen), 2) nonhematological mechanisms of improved performance after hypoxic exposure (Dr. Christopher Gore), 3) application of altitude/hypoxic training by elite athletes (Dr. Randall Wilber), and 4) military applications of hypoxic training (Dr. Stephen Muza).

  19. Optimization of High-Resolution Continuous Flow Analysis for Transient Climate Signals in Ice Cores

    DEFF Research Database (Denmark)

    Bigler, Matthias; Svensson, Anders; Kettner, Ernesto

    2011-01-01

    Over the past two decades, continuous flow analysis (CFA) systems have been refined and widely used to measure aerosol constituents in polar and alpine ice cores in very high-depth resolution. Here we present a newly designed system consisting of sodium, ammonium, dust particles, and electrolytic...... meltwater conductivity detection modules. The system is optimized for high- resolution determination of transient signals in thin layers of deep polar ice cores. Based on standard measurements and by comparing sections of early Holocene and glacial ice from Greenland, we find that the new system features...

  20. A global high-resolution data set of ice sheet topography, cavity geometry and ocean bathymetry

    DEFF Research Database (Denmark)

    Schaffer, Janin; Timmermann, Ralph; Arndt, Jan Erik

    2016-01-01

    of the Southern Ocean (IBCSO) version 1. While RTopo-1 primarily aimed at a good and consistent representation of the Antarctic ice sheet, ice shelves, and sub-ice cavities, RTopo-2now also contains ice topographies of the Greenland ice sheet and outlet glaciers. In particular, we aimed at agood representation....... For the continental shelf off Northeast Greenland and the floating ice tongue of Nioghalvfjerdsfjorden Glacier at about79 N, we incorporated a high-resolution digital bathymetry model considering original multibeam survey datafor the region. Radar data for surface topographies of the floating ice tongues...... for the geometry of Getz, Abbot, andFimbul ice shelf cavities. The data set is available in full and in regional subsets in NetCDF format from thePANGAEA database at doi:10.1594/PANGAEA.856844....

  1. Two-phase convection in Ganymede's high-pressure ice layer - Implications for its geological evolution

    Science.gov (United States)

    Kalousová, Klára; Sotin, Christophe; Choblet, Gaël; Tobie, Gabriel; Grasset, Olivier

    2018-01-01

    Ganymede, the largest moon in the solar system, has a fully differentiated interior with a layer of high-pressure (HP) ice between its deep ocean and silicate mantle. In this paper, we study the dynamics of this layer using a numerical model of two-phase ice-water mixture in two-dimensional Cartesian geometry. While focusing on the generation of water at the silicate/HP ice interface and its upward migration towards the ocean, we investigate the effect of bottom heat flux, the layer thickness, and the HP ice viscosity and permeability. Our results suggest that melt can be generated at the silicate/HP ice interface for small layer thickness ( ≲ 200 km) and high values of heat flux ( ≳ 20 mW m-2) and viscosity ( ≳ 1015 Pa s). Once generated, the water is transported through the layer by the upwelling plumes. Depending on the vigor of convection, it stays liquid or it may freeze before melting again as the plume reaches the temperate (partially molten) layer at the boundary with the ocean. The thickness of this layer as well as the amount of melt that is extracted from it is controlled by the permeability of the HP ice. This process constitutes a means of transporting volatiles and salts that might have dissolved into the melt present at the silicate/HP ice interface. As the moon cools down, the HP ice layer becomes less permeable because the heat flux from the silicates decreases and the HP ice layer thickens.

  2. Numerical simulation of altitude impact on pulverized coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Pei, Xiaohui; He, Boshu; Ling, Ling; Wang, Lei [Beijing Jiaotong Univ., Beijing (China). Inst. of Mechanical, Electronic and Control Engineering

    2013-07-01

    A drop-tube Furnace simulation model has been developed to investigate the pulverized coal combustion characteristics under different altitudes using the commercially available software Fluent. The altitude conditions of 0, 500, 1,000, 1,500 m have been discussed. The results included the fields of temperature, pressure, velocity, the coal burnout, CO burnout and NO emission in the tube furnace. The variation of these parameters with altitude has been analyzed. The coal combustion characteristics were affected by the altitude. The time and space for coal burnout should be increased with the rise of altitude. The valuable results could be referenced in the design of coal- fired furnaces for the high altitude areas.

  3. Airborne geophysics for mesoscale observations of polar sea ice in a changing climate

    Science.gov (United States)

    Hendricks, S.; Haas, C.; Krumpen, T.; Eicken, H.; Mahoney, A. R.

    2016-12-01

    Sea ice thickness is an important geophysical parameter with a significant impact on various processes of the polar energy balance. It is classified as Essential Climate Variable (ECV), however the direct observations of the large ice-covered oceans are limited due to the harsh environmental conditions and logistical constraints. Sea-ice thickness retrieval by the means of satellite remote sensing is an active field of research, but current observational capabilities are not able to capture the small scale variability of sea ice thickness and its evolution in the presence of surface melt. We present an airborne observation system based on a towed electromagnetic induction sensor that delivers long range measurements of sea ice thickness for a wide range of sea ice conditions. The purpose-built sensor equipment can be utilized from helicopters and polar research aircraft in multi-role science missions. While airborne EM induction sounding is used in sea ice research for decades, the future challenge is the development of unmanned aerial vehicle (UAV) platform that meet the requirements for low-level EM sea ice surveys in terms of range and altitude of operations. The use of UAV's could enable repeated sea ice surveys during the the polar night, when manned operations are too dangerous and the observational data base is presently very sparse.

  4. Convergent Evolution of Hemoglobin Function in High-Altitude Andean Waterfowl Involves Limited Parallelism at the Molecular Sequence Level.

    Directory of Open Access Journals (Sweden)

    Chandrasekhar Natarajan

    2015-12-01

    Full Text Available A fundamental question in evolutionary genetics concerns the extent to which adaptive phenotypic convergence is attributable to convergent or parallel changes at the molecular sequence level. Here we report a comparative analysis of hemoglobin (Hb function in eight phylogenetically replicated pairs of high- and low-altitude waterfowl taxa to test for convergence in the oxygenation properties of Hb, and to assess the extent to which convergence in biochemical phenotype is attributable to repeated amino acid replacements. Functional experiments on native Hb variants and protein engineering experiments based on site-directed mutagenesis revealed the phenotypic effects of specific amino acid replacements that were responsible for convergent increases in Hb-O2 affinity in multiple high-altitude taxa. In six of the eight taxon pairs, high-altitude taxa evolved derived increases in Hb-O2 affinity that were caused by a combination of unique replacements, parallel replacements (involving identical-by-state variants with independent mutational origins in different lineages, and collateral replacements (involving shared, identical-by-descent variants derived via introgressive hybridization. In genome scans of nucleotide differentiation involving high- and low-altitude populations of three separate species, function-altering amino acid polymorphisms in the globin genes emerged as highly significant outliers, providing independent evidence for adaptive divergence in Hb function. The experimental results demonstrate that convergent changes in protein function can occur through multiple historical paths, and can involve multiple possible mutations. Most cases of convergence in Hb function did not involve parallel substitutions and most parallel substitutions did not affect Hb-O2 affinity, indicating that the repeatability of phenotypic evolution does not require parallelism at the molecular level.

  5. High pressure ices are not the end of the story for large icy moons habitability: experimental studies of salts effects on high pressure ices and the implications for icy worlds large hydrosphere structure and chemical evolution

    Science.gov (United States)

    Journaux, Baptiste; Abramson, Evan; Brown, J. Michael; Bollengier, Olivier

    2017-10-01

    The presence of several phases of deep high-pressure ices in large icy moons hydrosphere has often been pointed as a major limitation for the habitability of an uppermost ocean. As they are gravitationally stable bellow liquid H2O, they are thought to act as a chemical barrier between the rocky bed and the ocean. Solutes, including salt species such as NaCl and MgSO4, have been suggested inside icy world oceans from remote sensing, magnetic field measurements and chondritic material alteration models. Unfortunately, the pressures and temperatures inside these hydrospheres are very different from the one found in Earth aqueous environments, so most of our current thermodynamic databases do not cover the range of conditions relevant for modeling realistically large icy worlds interiors.Recent experimental results have shown that the presence of solutes, and more particularly salts, in equilibrium with high pressure ices have large effects on the stability, buoyancy and chemistry of all the phases present at these extreme conditions.In particular brines have been measured to be sometimes more dense than the high pressure ices at melting conditions, possibly creating several oceanic layer "sandwiched" in between two ices shells or in contact with the rocky bed.Other effects currently being investigated by our research group also covers ice melting curve depressions that depend on the salt species and incorporation of solutes inside the crystallographic lattice of high pressure ices. Both of these could have very important implication at the planetary scale, enabling thicker/deeper liquid oceans, and allowing chemical transportation through the high pressure ice layer in large icy worlds.We will present the latest results obtained in-situ using diamond anvil cell high pressure allowing to probe the density, chemistry and thermodynamic properties of high pressure ice and aqueous solutions in equilibrium with Na-Mg-SO4-Cl ionic species.We will also discuss the new

  6. High altitude induced anorexia: effect of changes in leptin and oxidative stress levels.

    Science.gov (United States)

    Vats, Praveen; Singh, Vijay Kumar; Singh, Som Nath; Singh, Shashi Bala

    2007-01-01

    High altitude (HA) exposure usually leads to a significant weight loss in non-acclimatized humans. Anorexia is believed to be the main cause of this body weight loss. Appetite regulatory peptides, i.e. leptin and neuropeptide Y play a key role in food intake and energy homeostasis. Recent studies suggests increased oxidative stress during HA exposure. In present study effect of HA exposure on levels of leptin and NPY was evaluated along with N-acetyl cysteine (NAC) and vitamin E supplementation in relation to food intake and body weight changes. The study was conducted on 30 healthy male volunteers (age 19-29 years). Subjects were divided randomly into three groups of 10 each. Group 1 (placebo) supplemented with 400 mg of calcium gluconate, group 2 and 3 were supplemented with 400 mg of NAC and 400 mg vitamin E, respectively per day. The study was conducted at low altitude (320 m, Phase I), at HA 3600 m (Phase II) and at an altitude of 4580 m (Phase III). On HA exposure significant reduction in plasma leptin levels was observed in all the groups on day 2 (Phase II) along with decrease in food intake and reduction in body weight. Statistically significant increase in blood malondialdehyde (MDA) levels was seen in all the groups on HA exposure (Phase II, Day 2), but the maximum increase was in case of placebo group (65.1%) on day 2 (Phase II) in comparison to low altitude values. The decrease in energy intake was almost same in all the groups indicating that antioxidant supplementation did not provide any protection against HA anorexia. From the study, it may be concluded that leptin and oxidative stress possibly are not the key players for HA anorexia.

  7. High Ice Water Concentrations in the 19 August 2015 Coastal Mesoconvective System

    Science.gov (United States)

    Proctor, Fred H.; Harrah, Steven; Switzer, George F.; Strickland, Justin K.; Hunt, Patricia J.

    2017-01-01

    During August 2015, NASA's DC-8 research aircraft was flown into High Ice Water Content (HIWC) events as part of a three-week campaign to collect airborne radar data and to obtain measurements from microphysical probes. Goals for this flight campaign included improved characterization of HIWC events, especially from an airborne radar perspective. This paper focuses on one of the flight days, in which a coastal mesoscale convective system (MCS) was investigated for HIWC conditions. The system appears to have been maintained by bands of convection flowing in from the Gulf of Mexico. These convective bands were capped by a large cloud canopy, which masks the underlying structure if viewed from an infrared sensing satellite. The DC-8 was equipped with an IsoKinetic Probe that measured ice concentrations of up to 2.3 g m(exp -3) within the cloud canopy of this system. Sustained measurements of ice crystals with concentrations exceeding 1 g m(exp -3) were encountered for up to ten minutes of flight time. Airborne Radar reflectivity factors were found to be weak within these regions of high ice water concentrations, suggesting that Radar detection of HIWC would be a challenging endeavor. This case is then investigated using a three-dimensional numerical cloud model. Profiles of ice water concentrations and radar reflectivity factor demonstrate similar magnitudes and scales between the flight measurements and model simulation. Also discussed are recent modifications to the numerical model's ice-microphysics that are based on measurements during the flight campaign. The numerical model and its updated ice-microphysics are further validated with a simulation of a well-known case of a supercell hailstorm measured during the Cooperative Convective Precipitation Experiment. Differences in HIWC between the continental supercell and the coastal MCS are discussed.

  8. Pulmonary gas exchange at maximal exercise in Danish lowlanders during 8 wk of acclimatization to 4,100 m and in high-altitude Aymara natives

    DEFF Research Database (Denmark)

    Lundby, Carsten; Calbet, Jose A L; van Hall, Gerrit

    2004-01-01

    We aimed to test effects of altitude acclimatization on pulmonary gas exchange at maximal exercise. Six lowlanders were studied at sea level, in acute hypoxia (AH), and after 2 and 8 wk of acclimatization to 4,100 m (2W and 8W) and compared with Aymara high-altitude natives residing...... in AH but increased significantly with acclimatization (51 +/- 1.1, 58 +/- 1.7, and 62 +/- 1.6 mmHg in AH, 2W, and 8W, respectively). PaO2 in lowlanders reached levels that were not different from those in high-altitude natives (66 +/- 1.2 mmHg). Arterial O2 saturation (SaO2) decreased during maximum......, but even acclimatization for 8 wk is insufficient to achieve levels reached by high-altitude natives....

  9. An automated approach for mapping persistent ice and snow cover over high latitude regions

    Science.gov (United States)

    Selkowitz, David J.; Forster, Richard R.

    2016-01-01

    We developed an automated approach for mapping persistent ice and snow cover (glaciers and perennial snowfields) from Landsat TM and ETM+ data across a variety of topography, glacier types, and climatic conditions at high latitudes (above ~65°N). Our approach exploits all available Landsat scenes acquired during the late summer (1 August–15 September) over a multi-year period and employs an automated cloud masking algorithm optimized for snow and ice covered mountainous environments. Pixels from individual Landsat scenes were classified as snow/ice covered or snow/ice free based on the Normalized Difference Snow Index (NDSI), and pixels consistently identified as snow/ice covered over a five-year period were classified as persistent ice and snow cover. The same NDSI and ratio of snow/ice-covered days to total days thresholds applied consistently across eight study regions resulted in persistent ice and snow cover maps that agreed closely in most areas with glacier area mapped for the Randolph Glacier Inventory (RGI), with a mean accuracy (agreement with the RGI) of 0.96, a mean precision (user’s accuracy of the snow/ice cover class) of 0.92, a mean recall (producer’s accuracy of the snow/ice cover class) of 0.86, and a mean F-score (a measure that considers both precision and recall) of 0.88. We also compared results from our approach to glacier area mapped from high spatial resolution imagery at four study regions and found similar results. Accuracy was lowest in regions with substantial areas of debris-covered glacier ice, suggesting that manual editing would still be required in these regions to achieve reasonable results. The similarity of our results to those from the RGI as well as glacier area mapped from high spatial resolution imagery suggests it should be possible to apply this approach across large regions to produce updated 30-m resolution maps of persistent ice and snow cover. In the short term, automated PISC maps can be used to rapidly

  10. Development of a bioaerosol single particle detector (BIO IN) for the fast ice nucleus chamber FINCH

    Science.gov (United States)

    Bundke, U.; Reimann, B.; Nillius, B.; Jaenicke, R.; Bingemer, H.

    2009-10-01

    In this work we present the setup and first tests of our new BIO IN detector. This detector is designed to classify atmospheric ice nuclei (IN) for their biological content. Biological material is identified via its auto-fluorescence (intrinsic fluorescence) after irradiation with UV radiation. Ice nuclei are key substances for precipitation development via the Bergeron-Findeisen process. The level of scientific knowledge regarding origin and climatology (temporal and spatial distribution) of IN is very low. Some biological material is known to be active as IN even at relatively high temperatures of up to -2°C (e.g. pseudomonas syringae bacteria). These biological IN could have a strong influence on the formation of clouds and precipitation. We have designed the new BIO IN sensor to analyze the abundance of IN of biological origin. The instrument will be flown on one of the first missions of the new German research aircraft ''HALO'' (High Altitude and LOng Range).

  11. Genotyping the High Altitude Mestizo Ecuadorian Population Affected with Prostate Cancer

    Directory of Open Access Journals (Sweden)

    Andrés López-Cortés

    2017-01-01

    Full Text Available Prostate cancer (PC is the second most commonly diagnosed type of cancer in males with 1,114,072 new cases in 2015. The MTHFR enzyme acts in the folate metabolism, which is essential in methylation and synthesis of nucleic acids. MTHFR C677T alters homocysteine levels and folate assimilation associated with DNA damage. Androgens play essential roles in prostate growth. The SRD5A2 enzyme metabolizes testosterone and the V89L polymorphism reduces in vivo SRD5A2 activity. The androgen receptor gene codes for a three-domain protein that contains two polymorphic trinucleotide repeats (CAG, GGC. Therefore, it is essential to know how PC risk is associated with clinical features and polymorphisms in high altitude Ecuadorian mestizo populations. We analyzed 480 healthy and 326 affected men from our three retrospective case-control studies. We found significant association between MTHFR C/T (odds ratio [OR] = 2.2; P=0.009, MTHFR C/T+T/T (OR = 2.22; P=0.009, and PC. The SRD5A2 A49T substitution was associated with higher pTNM stage (OR = 2.88; P=0.039 and elevated Gleason grade (OR = 3.15; P=0.004. Additionally, patients with ≤21 CAG repeats have an increased risk of developing PC (OR = 2.99; P<0.001. In conclusion, genotype polymorphism studies are important to characterize genetic variations in high altitude mestizo populations.

  12. Gokyo Khumbu/Ama Dablam Trek 2012: effects of physical training and high-altitude exposure on oxidative metabolism, muscle composition, and metabolic cost of walking in women.

    Science.gov (United States)

    Tam, E; Bruseghini, P; Calabria, E; Dal Sacco, L; Doria, C; Grassi, B; Pietrangelo, T; Pogliaghi, S; Reggiani, C; Salvadego, D; Schena, F; Toniolo, L; Verratti, V; Vernillo, G; Capelli, Carlo

    2016-01-01

    We investigated the effects of moderate-intensity training at low and high altitude on VO2 and QaO2 kinetics and on myosin heavy-chain expression (MyHC) in seven women (36.3 yy ± 7.1; 65.8 kg ± 11.7; 165 cm ± 8) who participated in two 12- to 14-day trekking expeditions at low (598 m) and high altitude (4132 m) separated by 4 months of recovery. Breath-by-breath VO2 and beat-by-beat QaO2 at the onset of moderate-intensity cycling exercise and energy cost of walking (Cw) were assessed before and after trekking. MyHC expression of vastus lateralis was evaluated before and after low-altitude and after high-altitude trekking; muscle fiber high-resolution respirography was performed at the beginning of the study and after high-altitude trekking. Mean response time of VO2 kinetics was faster (P = 0.002 and P = 0.001) and oxygen deficit was smaller (P = 0.001 and P = 0.0004) after low- and high-altitude trekking, whereas ˙ QaO2 kinetics and Cw did not change. Percentages of slow and fast isoforms of MyHC and mitochondrial mass were not affected by low- and high-altitude training. After training altitude, muscle fiber ADP-stimulated mitochondrial respiration was decreased as compared with the control condition (P = 0.016), whereas leak respiration was increased (P = 0.031), leading to a significant increase in the respiratory control ratio (P = 0.016). Although training did not significantly modify muscle phenotype, it induced beneficial adaptations of the oxygen transport-utilization systems witnessed by faster VO2 kinetics at exercise onset.

  13. High resolution modelling of the decreasing Arctic sea ice

    DEFF Research Database (Denmark)

    Madsen, K. S.; Rasmussen, T. A. S.; Blüthgen, Jonas

    2012-01-01

    The Arctic sea ice cover has been rapidly decreasing and thinning over the last decade, with minimum ice extent in 2007 and almost as low extent in 2011. This study investigates two aspects of the decreasing ice cover; first the large scale thinning and changing dynamics of the polar sea ice, and...

  14. Navigation and Positioning System Using High Altitude Platforms Systems (HAPS)

    Science.gov (United States)

    Tsujii, Toshiaki; Harigae, Masatoshi; Harada, Masashi

    Recently, some countries have begun conducting feasibility studies and R&D projects on High Altitude Platform Systems (HAPS). Japan has been investigating the use of an airship system that will function as a stratospheric platform for applications such as environmental monitoring, communications and broadcasting. If pseudolites were mounted on the airships, their GPS-like signals would be stable augmentations that would improve the accuracy, availability, and integrity of GPS-based positioning systems. Also, the sufficient number of HAPS can function as a positioning system independent of GPS. In this paper, a system design of the HAPS-based positioning system and its positioning error analyses are described.

  15. High Altitude Balloon Flight Path Prediction and Site Selection Based On Computer Simulations

    Science.gov (United States)

    Linford, Joel

    2010-10-01

    Interested in the upper atmosphere, Weber State University Physics department has developed a High Altitude Reconnaissance Balloon for Outreach and Research team, also known as HARBOR. HARBOR enables Weber State University to take a variety of measurements from ground level to altitudes as high as 100,000 feet. The flight paths of these balloons can extend as long as 100 miles from the launch zone, making the choice of where and when to fly critical. To ensure the ability to recover the packages in a reasonable amount of time, days and times are carefully selected using computer simulations limiting flight tracks to approximately 40 miles from the launch zone. The computer simulations take atmospheric data collected by National Oceanic and Atmospheric Administration (NOAA) to plot what flights might have looked like in the past, and to predict future flights. Using these simulations a launch zone has been selected in Duchesne Utah, which has hosted eight successful flights over the course of the last three years, all of which have been recovered. Several secondary launch zones in western Wyoming, Southern Idaho, and Northern Utah are also being considered.

  16. Using Airborne Lidar Data from IcePod to Measure Annual and Seasonal Ice Changes Over Greenland

    Science.gov (United States)

    Frearson, N.; Bertinato, C.; Das, I.

    2014-12-01

    The IcePod is a multi-sensor airborne science platform that supports a wide suite of instruments, including a Riegl VQ-580 infrared scanning laser, GPS-inertial positioning system, shallow and deep-ice radars, visible-wave and infrared cameras, and upward-looking pyrometer. These instruments allow us to image the ice from top to bottom, including the surface of melt-water plumes that originate at the ice-ocean boundary. In collaboration with the New York Air National Guard 109th Airlift Wing, the IcePod is flown on LC-130 aircraft, which presents the unique opportunity to routinely image the Greenland ice sheet several times within a season. This is particularly important for mass balance studies, as we can measure elevation changes during the melt season. During the 2014 summer, laser data was collected via IcePod over the Greenland ice sheet, including Russell Glacier, Jakobshavn Glacier, Eqip Glacier, and Summit Camp. The Icepod will also be routinely operated in Antarctica. We present the initial testing, calibration, and error estimates from the first set of laser data that were collected on IcePod. At a survey altitude of 1000 m, the laser swath covers ~ 1000 m. A Northrop-Grumman LN-200 tactical grade IMU is rigidly attached to the laser scanner to provide attitude data at a rate of 200 Hz. Several methods were used to determine the lever arm between the IMU center of navigation and GPS antenna phase center, terrestrial scanning laser, total station survey, and optimal estimation. Additionally, initial bore sight calibration flights yielded misalignment angles within an accuracy of ±4 cm. We also performed routine passes over the airport ramp in Kangerlussuaq, Greenland, comparing the airborne GPS and Lidar data to a reference GPS-based ground survey across the ramp, spot GPS points on the ramp and a nearby GPS base station. Positioning errors can severely impact the accuracy of a laser altimeter when flying over remote regions such as across the ice sheets

  17. Observed microphysical changes in Arctic mixed-phase clouds when transitioning from sea ice to open ocean

    Directory of Open Access Journals (Sweden)

    G. Young

    2016-11-01

    Full Text Available In situ airborne observations of cloud microphysics, aerosol properties, and thermodynamic structure over the transition from sea ice to ocean are presented from the Aerosol-Cloud Coupling And Climate Interactions in the Arctic (ACCACIA campaign. A case study from 23 March 2013 provides a unique view of the cloud microphysical changes over this transition under cold-air outbreak conditions. Cloud base lifted and cloud depth increased over the transition from sea ice to ocean. Mean droplet number concentrations, Ndrop, also increased from 110 ± 36 cm−3 over the sea ice to 145 ± 54 cm−3 over the marginal ice zone (MIZ. Downstream over the ocean, Ndrop decreased to 63 ± 30 cm−3. This reduction was attributed to enhanced collision-coalescence of droplets within the deep ocean cloud layer. The liquid water content increased almost four fold over the transition and this, in conjunction with the deeper cloud layer, allowed rimed snowflakes to develop and precipitate out of cloud base downstream over the ocean. The ice properties of the cloud remained approximately constant over the transition. Observed ice crystal number concentrations averaged approximately 0.5–1.5 L−1, suggesting only primary ice nucleation was active; however, there was evidence of crystal fragmentation at cloud base over the ocean. Little variation in aerosol particle number concentrations was observed between the different surface conditions; however, some variability with altitude was observed, with notably greater concentrations measured at higher altitudes ( >  800 m over the sea ice. Near-surface boundary layer temperatures increased by 13 °C from sea ice to ocean, with corresponding increases in surface heat fluxes and turbulent kinetic energy. These significant thermodynamic changes were concluded to be the primary driver of the microphysical evolution of the cloud. This study represents the first investigation, using in situ

  18. A Dynamic Model for the Evaluation of Aircraft Engine Icing Detection and Control-Based Mitigation Strategies

    Science.gov (United States)

    Simon, Donald L.; Rinehart, Aidan W.; Jones, Scott M.

    2017-01-01

    Aircraft flying in regions of high ice crystal concentrations are susceptible to the buildup of ice within the compression system of their gas turbine engines. This ice buildup can restrict engine airflow and cause an uncommanded loss of thrust, also known as engine rollback, which poses a potential safety hazard. The aviation community is conducting research to understand this phenomena, and to identify avoidance and mitigation strategies to address the concern. To support this research, a dynamic turbofan engine model has been created to enable the development and evaluation of engine icing detection and control-based mitigation strategies. This model captures the dynamic engine response due to high ice water ingestion and the buildup of ice blockage in the engines low pressure compressor. It includes a fuel control system allowing engine closed-loop control effects during engine icing events to be emulated. The model also includes bleed air valve and horsepower extraction actuators that, when modulated, change overall engine operating performance. This system-level model has been developed and compared against test data acquired from an aircraft turbofan engine undergoing engine icing studies in an altitude test facility and also against outputs from the manufacturers customer deck. This paper will describe the model and show results of its dynamic response under open-loop and closed-loop control operating scenarios in the presence of ice blockage buildup compared against engine test cell data. Planned follow-on use of the model for the development and evaluation of icing detection and control-based mitigation strategies will also be discussed. The intent is to combine the model and control mitigation logic with an engine icing risk calculation tool capable of predicting the risk of engine icing based on current operating conditions. Upon detection of an operating region of risk for engine icing events, the control mitigation logic will seek to change the

  19. Increases in .VO2max with "live high-train low" altitude training: role of ventilatory acclimatization.

    Science.gov (United States)

    Wilhite, Daniel P; Mickleborough, Timothy D; Laymon, Abigail S; Chapman, Robert F

    2013-02-01

    The purpose of this study was to estimate the percentage of the increase in whole body maximal oxygen consumption (.VO(2max)) that is accounted for by increased respiratory muscle oxygen uptake after altitude training. Six elite male distance runners (.VO(2max) = 70.6 ± 4.5 ml kg(-1) min(-1)) and one elite female distance runner (.VO(2max)) = 64.7 ml kg(-1) min(-1)) completed a 28-day "live high-train low" training intervention (living elevation, 2,150 m). Before and after altitude training, subjects ran at three submaximal speeds, and during a separate session, performed a graded exercise test to exhaustion. A regression equation derived from published data was used to estimate respiratory muscle .VO(2) (.VO(2RM)) using our ventilation (.VE) values. .VO(2RM) was also estimated retrospectively from a larger group of distance runners (n = 22). .VO(2max) significantly (p altitude (196 ± 59 ml min(-1)), while (.VE) at .VO(2max) also significantly (p altitude (201 ± 36 ml min(-1)), along with a 10.8 ± 2.1 l min(-1) increase in (.VE), thus requiring an estimated 27 % of Δ .VO(2max) Our data suggest that a substantial portion of the improvement in .VO(2max) with chronic altitude training goes to fuel the respiratory muscles as opposed to the musculature which directly contributes to locomotion. Consequently, the time-course of decay in ventilatory acclimatization following return to sea-level may have an impact on competitive performance.

  20. First Cluster results of the magnetic field structure of the mid- and high-altitude cusps

    Directory of Open Access Journals (Sweden)

    P. J. Cargill

    Full Text Available Magnetic field measurements from the four Cluster spacecraft from the mid- and high-altitude cusp are presented. Cluster underwent two encounters with the mid-altitude cusp during its commissioning phase (24 August 2000. Evidence for field-aligned currents (FACs was seen in the data from all three operating spacecraft from northern and southern cusps. The extent of the FACs was of the order of 1 RE in the X-direction, and at least 300 km in the Y-direction. However, fine-scale field structures with scales of the order of the spacecraft separation (300 km were observed within the FACs. In the northern crossing, two of the spacecraft appeared to lie along the same magnetic field line, and observed very well matched signals. However, the third spacecraft showed evidence for structuring transverse to the field on scales of a few hundred km. A crossing of the high-altitude cusp from 13 February 2001 is presented. It is revealed to be a highly dynamic structure with the boundaries moving with velocities ranging from a few km/s to tens of km/s, and having structure on timescales ranging from less than one minute up to several minutes. The cusp proper is associated with the presence of a very disordered magnetic field, which is entirely different from the magnetosheath turbulence.

    Key words. Magnetospheric physics (current systems; magnetopause, cusp, and boundary layers – Space plasma physics (discontinuities

  1. Middle-to-late Holocene palaeoenvironmental reconstruction from the A294 ice-cave record (Central Pyrenees, northern Spain)

    Science.gov (United States)

    Sancho, Carlos; Belmonte, Ánchel; Bartolomé, Miguel; Moreno, Ana; Leunda, María; López-Martínez, Jerónimo

    2018-02-01

    Perennial ice deposits in caves represent unique, but underexplored, terrestrial sequences that potentially contain outstanding palaeoclimatic records. Here, we present a pioneer palaeoenvironmental study of an ice deposit preserved in a small sag-type cave (A294) in the Central Pyrenees (northern Iberian Peninsula). The 9.25-m-thick sequence, which is dated from 6100 ± 107 to 1888 ± 64 cal BP, represents the oldest known firn ice record worldwide. The stratigraphy (detrital layers, unconformities, and cross stratification), plant macrofossils, and isotopic signature (similarity between the ice linear distribution, δ2H = 7.83δ18O + 8.4, and the Global Meteoric Water Line) of the ice point to the diagenesis of snow introduced to the cave by winter snowstorms. Four phases of rapid ice accumulation (6100-5515, 4945-4250, 3810-3155, and 2450-1890 cal BP) are related to wetter and colder winters. Comparison of the isotopic composition (δ18O and deuterium excess) of the ice with other paleoclimate records show that both source effects and the North Atlantic Oscillation (NAO) mechanism exert a dominant influence on the ice cave record. The NAO signal may be a combination of source effects and rainfall amount. Three intervals with low ice accumulation occurred between the phases of rapid accumulation and were related to drier, and possibly warmer, winters. These centennial-scale episodes appear to be in-phase with regional arid events, as established from high altitude lacustrine records and can be correlated to global Rapid Climate Change events. The current warming trend has dramatically decreased the volume of the ice deposit in cave A294.

  2. Measurements of ice nucleating particle concentrations at 242 K in the free troposphere

    Science.gov (United States)

    Lacher, L.; Lohmann, U.; Boose, Y.; Zipori, A.; Herrmann, E.; Bukowiecki, N.; Steinbacher, M.; Gute, E.; Kanji, Z. A.

    2017-12-01

    Clouds containing ice play an important role in the Earth's system, but some fundamental knowledge on their formation and further development is still missing. The phase change from vapor or liquid to ice in the atmosphere can occur heterogeneously in the presence of ice nucleating particles (INPs) at temperatures warmer, and supersaturations lower than required for homogeneous freezing. Only a small fraction of particles in an environment relevant for the occurrence of ice- and mixed-phase clouds are INPs, and their identification and quantification remains challenging. We measure INP concentrations with the ETH Horizontal Ice Nucleation Chamber (HINC) at the High Altitude Research Station Jungfraujoch (JFJ) during several field campaigns in different seasons and years. The measurements are performed at 242 K and above water saturation, representing ice- and mixed-phase clouds conditions. Due to its elevation of 3580 m a.s.l. the site encounters mostly free tropospheric conditions, and is influenced by boundary layer injections up to 80% of the time in summer. JFJ regularly encounters Saharan dust events and receives air masses of marine origin, which can both occur within the free troposphere. Our measurements show that INP concentrations in the free troposphere do not follow a seasonal cycle. They are remarkably constant, with concentrations from 0.5 - 8 L-1 (interquartile range), which compares well to measurements performed under the same conditions at another location within the free troposphere, the Izaña Atmospheric Research Station in Tenerife. At JFJ, correlations with parameters of physical properties of ambient particles, meteorology and air mass characteristics do not show a single best estimator to predict INP concentrations, emphasizing the complexity of ice nucleation in the free troposphere. Increases in INP concentrations of a temporary nature were observed in the free troposphere during Saharan dust events and marine air mass influence, which

  3. High abundances of potentially active ammonia-oxidizing bacteria and archaea in oligotrophic, high-altitude lakes of the Sierra Nevada, California, USA.

    Directory of Open Access Journals (Sweden)

    Curtis J Hayden

    Full Text Available Nitrification plays a central role in the nitrogen cycle by determining the oxidation state of nitrogen and its subsequent bioavailability and cycling. However, relatively little is known about the underlying ecology of the microbial communities that carry out nitrification in freshwater ecosystems--and particularly within high-altitude oligotrophic lakes, where nitrogen is frequently a limiting nutrient. We quantified ammonia-oxidizing archaea (AOA and bacteria (AOB in 9 high-altitude lakes (2289-3160 m in the Sierra Nevada, California, USA, in relation to spatial and biogeochemical data. Based on their ammonia monooxygenase (amoA genes, AOB and AOA were frequently detected. AOB were present in 88% of samples and were more abundant than AOA in all samples. Both groups showed >100 fold variation in abundance between different lakes, and were also variable through time within individual lakes. Nutrient concentrations (ammonium, nitrite, nitrate, and phosphate were generally low but also varied across and within lakes, suggestive of active internal nutrient cycling; AOB abundance was significantly correlated with phosphate (r(2 = 0.32, p<0.1, whereas AOA abundance was inversely correlated with lake elevation (r(2 = 0.43, p<0.05. We also measured low rates of ammonia oxidation--indicating that AOB, AOA, or both, may be biogeochemically active in these oligotrophic ecosystems. Our data indicate that dynamic populations of AOB and AOA are found in oligotrophic, high-altitude, freshwater lakes.

  4. Acoustic detection of ultra-high energy cascades in ice

    Energy Technology Data Exchange (ETDEWEB)

    Boeser, S.

    2006-12-08

    Current underwater optical neutrino telescopes are designed to detect neutrinos from astrophysical sources with energies in the TeV range. Due to the low fluxes and small cross sections, no high energy neutrinos of extraterrestrial origin have been observed so far. Only the Cherenkov neutrino detectors on the km{sup 3} scale that are currently under construction will have the necessary volume to observe these rare interactions. For the guaranteed source of neutrinos from interactions of the ultra-high energy cosmic at EeV energies rays with the ambient cosmic microwave background, event rates of only one per year are expected in these experiments. To measure the flux and verify the predicted cross sections of these cosmogenic neutrinos, an observed volume of the order of 100 km{sup 3} will be necessary, that will not be feasible with existing detection techniques. Alternative methods are required to build a detector on these scales. One promising idea is to record the acoustic waves generated in hadronic or electromagnetic cascades following the neutrino interaction. The higher amplitudes of the sonic signal and the large expected absorption length of sound favour South Polar ice instead of sea water as a medium. The prerequisites for an estimate of the potential of such a detector are suitable acoustic sensors, a verification of the model of thermo-acoustic sound generation and a determination of the acoustic properties of the ice. In a theoretical derivation the mechanism of thermo-elastic excitation of acoustic waves was shown to be equivalent for isotropic solids and liquids. Following a detailed analysis of the existing knowledge a simulation study of a hybrid optical-radio-acoustic detector has been performed. Ultrasonic sensors dedicated to in-ice application were developed and have been used to record acoustic signals from intense proton and laser beams in water and ice. With the obtained experience, the hitherto largest array of acoustic sensors and

  5. Acoustic detection of ultra-high energy cascades in ice

    International Nuclear Information System (INIS)

    Boeser, S.

    2006-01-01

    Current underwater optical neutrino telescopes are designed to detect neutrinos from astrophysical sources with energies in the TeV range. Due to the low fluxes and small cross sections, no high energy neutrinos of extraterrestrial origin have been observed so far. Only the Cherenkov neutrino detectors on the km 3 scale that are currently under construction will have the necessary volume to observe these rare interactions. For the guaranteed source of neutrinos from interactions of the ultra-high energy cosmic at EeV energies rays with the ambient cosmic microwave background, event rates of only one per year are expected in these experiments. To measure the flux and verify the predicted cross sections of these cosmogenic neutrinos, an observed volume of the order of 100 km 3 will be necessary, that will not be feasible with existing detection techniques. Alternative methods are required to build a detector on these scales. One promising idea is to record the acoustic waves generated in hadronic or electromagnetic cascades following the neutrino interaction. The higher amplitudes of the sonic signal and the large expected absorption length of sound favour South Polar ice instead of sea water as a medium. The prerequisites for an estimate of the potential of such a detector are suitable acoustic sensors, a verification of the model of thermo-acoustic sound generation and a determination of the acoustic properties of the ice. In a theoretical derivation the mechanism of thermo-elastic excitation of acoustic waves was shown to be equivalent for isotropic solids and liquids. Following a detailed analysis of the existing knowledge a simulation study of a hybrid optical-radio-acoustic detector has been performed. Ultrasonic sensors dedicated to in-ice application were developed and have been used to record acoustic signals from intense proton and laser beams in water and ice. With the obtained experience, the hitherto largest array of acoustic sensors and transmitters was

  6. Intercomparison of passive microwave sea ice concentration retrievals over the high-concentration Arctic sea ice

    DEFF Research Database (Denmark)

    andersen, susanne; Tonboe, R.; Kaleschke, L.

    2007-01-01

    [1] Measurements of sea ice concentration from the Special Sensor Microwave Imager (SSM/I) using seven different algorithms are compared to ship observations, sea ice divergence estimates from the Radarsat Geophysical Processor System, and ice and water surface type classification of 59 wide...... with sensor noise between 1.3 and 1.8%. This is in accord with variability estimated from analysis of SSM/I time series. Algorithms, which primarily use 85 GHz information, consistently give the best agreement with both SAR ice concentrations and ship observations. Although the 85 GHz information is more...... sensitive to atmospheric influences, it was found that the atmospheric contribution is secondary to the influence of the surface emissivity variability. Analysis of the entire SSM/I time series shows that there are significant differences in trend between sea ice extent and area, using different algorithms...

  7. Effects of high-altitude exercise training on contractile function of rat skinned cardiomyocyte.

    Science.gov (United States)

    Cazorla, O; Aït Mou, Y; Goret, L; Vassort, G; Dauzat, M; Lacampagne, A; Tanguy, S; Obert, P

    2006-09-01

    Previous studies have questioned whether there is an improved cardiac function after high-altitude training. Accordingly, the present study was designed specifically to test whether this apparent blunted response of the whole heart to training can be accounted for by altered mechanical properties at the cellular level. Adult rats were trained for 5 weeks under normoxic (N, NT for sedentary and trained animals, respectively) or hypobaric hypoxic (H, HT) conditions. Cardiac morphology and function were evaluated by echocardiography. Calcium Ca2+ sensitivity of the contractile machinery was estimated in skinned cardiomyocytes isolated from the left ventricular (LV) sub-epicardium (Epi) and sub-endocardium (Endo) at short and long sarcomere lengths (SL). Cardiac remodelling was harmonious (increase in wall thickness with chamber dilatation) in NT rats and disharmonious (hypertrophy without chamber dilatation) in HT rats. Contrary to NT rats, HT rats did not exhibit enhancement in global cardiac performance evaluated by echocardiography. Stretch- dependent Ca2+ sensitization of the myofilaments (cellular index of the Frank-Starling mechanism) increased from Epi to Endo in N rats. Training in normoxic conditions further increased this stretch-dependent Ca2+ sensitization. Chronic hypoxia did not significantly affect myofibrilar Ca2+ sensitivity. In contrast, high-altitude training decreased Ca2+ sensitivity of the myofilaments at both SL, mostly in Endo cells, resulting in a loss of the transmural gradient of the stretch-dependent Ca2+ sensitization. Expression of myosin heavy chain isoforms was affected both by training and chronic hypoxia but did not correlate with mechanical data. Training at sea level increased the transmural gradient of stretch-dependent Ca2+ sensitization of the myofilaments, accounting for an improved Frank-Starling mechanism. High-altitude training depressed myofilament response to Ca2+, especially in the Endo layer. This led to a reduction in

  8. Cane pruning on Chardonnay grapevine in the high-altitude regions of Southern Brazil

    Directory of Open Access Journals (Sweden)

    Filho José Luiz Marcon

    2016-01-01

    Full Text Available High-altitude regions of southern Brazil, located above 900 m above sea level, the cordon training with spur pruning is widely used because of easier application. In these regions, Chardonnay wine grape shows potential to produce quality wines, however, in commercial vineyards, the training system used has not provided productivities that makes economically viable the cultivation of this variety. Given this, the present study aimed to evaluate the effect of different cane-pruning systems on the vegetative, productive and enological potential of Chardonnay grapevines grown in the high-altitude region of Southern Brazil. The experiment was conducted in a commercial Chardonnay vineyard, located in São Joaquim – Santa Catarina State (28o17 ′39”S and 49∘ 55′56” W, to 1230 m a.s.l during 2015 and 2016 vintages. Chardonnay vines (grafted on 1103 Paulsen were planted in 2010, with a 3.0 m (row × 1.0 m (vine spacing. The treatments consisted of different cane-pruning systems: Cordon spur-pruning (control; Sylvoz; Cazenave; Capovolto; single Guyot and double Guyot. Pruning was performed in August of each year when the buds were in the green tip developmental stage. Data was analyzed by Scott Knott test (p < 0.05 following a randomized block design with four replicates, each consisting of 12 vines per plot. We observed higher yield in the Cazenave and double Guyot training system with three and two more tons of grapes than spur-pruning respectively. The bud fertility was higher in plants trained in double Guyot. Vines spur-pruned showed higher relation of leaf area: production, with values above 100 cm2 g−1 grape at 2016 vintage. Commercial maturity of grapes (soluble solids, acidity and polyphenols did not differ among training systems studied. The results suggest that cane-pruning systems could be an alternative to increase production efficiency of Chardonnay in high-altitude region of southern Brazil.

  9. Using high resolution tritium profiles to quantify the effects of melt on two Spitsbergen ice cores

    NARCIS (Netherlands)

    van der Wel, L.G.; Streurman, H.J.; Isaksson, E.; Helsen, M.M.; van de Wal, R.S.W.; Martma, T.; Pohjola, V.A.; Moore, J.C.; Meijer, H.A.J.

    2011-01-01

    Ice cores from small ice caps provide valuable climatic information, additional to that of Greenland and Antarctica. However, their integrity is usually compromised by summer meltwater percolation. To determine to what extent this can affect such ice cores, we performed high-resolution tritium

  10. Using high-resolution tritium profiles to quantify the effects of melt on two Spitsbergen ice cores

    NARCIS (Netherlands)

    Wel, L.G. van der; Streurman, H.J.; Isaksson, E.; Helsen, M.M.; Wal, R.S.W. van de; Martma, T.; Pohjola, V.A.; Moore, J.C.; Meijer, H.A.J.

    2011-01-01

    Ice cores from small ice caps provide valuable climatic information, additional to that of Greenland and Antarctica. However, their integrity is usually compromised by summer meltwater percolation. To determine to what extent this can affect such ice cores, we performed high-resolution tritium

  11. Red Maca (Lepidium meyenii), a Plant from the Peruvian Highlands, Promotes Skin Wound Healing at Sea Level and at High Altitude in Adult Male Mice.

    Science.gov (United States)

    Nuñez, Denisse; Olavegoya, Paola; Gonzales, Gustavo F; Gonzales-Castañeda, Cynthia

    2017-12-01

    Nuñez, Denisse, Paola Olavegoya, Gustavo F. Gonzales, and Cynthia Gonzales-Castañeda. Red maca (Lepidium meyenii), a plant from the Peruvian highlands, promotes skin wound healing at sea level and at high altitude in adult male mice. High Alt Med Biol 18:373-383, 2017.-Wound healing consists of three simultaneous phases: inflammation, proliferation, and remodeling. Previous studies suggest that there is a delay in the healing process in high altitude, mainly due to alterations in the inflammatory phase. Maca (Lepidium meyenii) is a Peruvian plant with diverse biological properties, such as the ability to protect the skin from inflammatory lesions caused by ultraviolet radiation, as well as its antioxidant and immunomodulatory properties. The aim of this study was to determine the effect of high altitude on tissue repair and the effect of the topical administration of the spray-dried extract of red maca (RM) in tissue repair. Studies were conducted in male Balb/c mice at sea level and high altitude. Lesions were inflicted through a 10 mm-diameter excisional wound in the skin dorsal surface. Treatments consisted of either (1) spray-dried RM extract or (2) vehicle (VH). Animals wounded at high altitude had a delayed healing rate and an increased wound width compared with those at sea level. Moreover, wounding at high altitude was associated with an increase in inflammatory cells. Treatment with RM accelerated wound closure, decreased the level of epidermal hyperplasia, and decreased the number of inflammatory cells at the wound site. In conclusion, RM at high altitude generate a positive effect on wound healing, decreasing the number of neutrophils and increasing the number of macrophages in the wound healing at day 7 postwounding. This phenomenon is not observed at sea level.

  12. Establishment of extracorporeal circulation of artificial liver support system in high altitude region

    Directory of Open Access Journals (Sweden)

    Ming-sen ZHANG

    2011-01-01

    Full Text Available Objective To establish extracorporeal circulation in big animal suitable for the research on artificial liver support system in high altitude region.Methods Under the anesthesia of ketamine hydrochloride/diazepam IV,cannulation of common carotid artery/external jugular vein(n=3 and inferior vena cava via the left external jugular vein/right external jugular vein(n=3,was respectively performed on six healthy Chang-Bai piglets adapted to native environment(altitude 3700m.One day after that,the extracorporeal circulation was performed at a progressively elevated blood current velocity,and the general condition of the animals,blood pressure,HR,bleeding tendoncy of the experimental pigs and coagulation in the cannulae were observed.Results On the premise that the hemodynamics was not influenced,the highest blood current velocity was 133.33±28.87ml/min,the lowest heparin maintaining speed amounted to 138.67±12.22mg/h,and the bleeding tendency and blood coagulation in the cannula was significant in the group of common carotid artery/external jugular vein intubation.While the highest blood current velocity was 400ml/min,the lowest heparin maintaining speed was 26.67±9.24mg/h,no bleeding tendency or obvious cannular blood coagulation were observed in the group of cannulation of inferior vena cava via the left external jugular vein/right external jugular vein.These untoward results were significantly less or slight than that of the former group(P < 0.01.Conclusion It is suitable to perform research of artificial liver support system on piglets in high altitude region by establishing extracorporeal circulation by the way of inferior vena cava with cannulation passing through the left external jugular vein/right external jugular vein with the blood current velocity of 400ml/min.

  13. Dietary Recommendations for Cyclists during Altitude Training

    Science.gov (United States)

    Michalczyk, Małgorzata; Czuba, Miłosz; Zydek, Grzegorz; Zając, Adam; Langfort, Józef

    2016-01-01

    The concept of altitude or hypoxic training is a common practice in cycling. However, several strategies for training regimens have been proposed, like “live high, train high” (LH-TH), “live high, train low” (LH-TL) or “intermittent hypoxic training” (IHT). Each of them combines the effect of acclimatization and different training protocols that require specific nutrition. An appropriate nutrition strategy and adequate hydration can help athletes achieve their fitness and performance goals in this unfriendly environment. In this review, the physiological stress of altitude exposure and training will be discussed, with specific nutrition recommendations for athletes training under such conditions. However, there is little research about the nutrition demands of athletes who train at moderate altitude. Our review considers energetic demands and body mass or body composition changes due to altitude training, including respiratory and urinary water loss under these conditions. Carbohydrate intake recommendations and hydration status are discussed in detail, while iron storage and metabolism is also considered. Last, but not least the risk of increased oxidative stress under hypoxic conditions and antioxidant supplementation suggestions are presented. PMID:27322318

  14. HURRICANE AND SEVERE STORM SENTINEL (HS3) GLOBAL HAWK HIGH ALTITUDE MMIC SOUNDING RADIOMETER (HAMSR) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The Hurricane and Severe Storm Sentinel (HS3) Global Hawk High Altitude MMIC Sounding Radiometer (HAMSR) datasets include measurements gathered by the HAMSR...

  15. Measurement of the energy spectrum of cosmic-ray induced neutrons aboard an ER-2 high-altitude airplane

    CERN Document Server

    Goldhagen, P E; Kniss, T; Reginatto, M; Singleterry, R C; Van Steveninck, W; Wilson, J W

    2002-01-01

    Crews working on present-day jet aircraft are a large occupationally exposed group with a relatively high average effective dose from galactic cosmic radiation. Crews of future high-speed commercial aircraft flying at higher altitudes would be even more exposed. To help reduce the significant uncertainties in calculations of such exposures, the atmospheric ionizing radiation (AIR) project, an international collaboration of 15 laboratories, made simultaneous radiation measurements with 14 instruments on five flights of a NASA ER-2 high-altitude aircraft. The primary AIR instrument was a highly sensitive extended-energy multisphere neutron spectrometer with lead and steel shells placed within the moderators of two of its 14 detectors to enhance response at high energies. Detector responses were calculated for neutrons and charged hadrons at energies up to 100 GeV using MCNPX. Neutron spectra were unfolded from the measured count rates using the new MAXED code. We have measured the cosmic-ray neutron spectrum (t...

  16. Effect of high altitude exposure on the hemodynamics of the bidirectional Glenn physiology: modeling incremented pulmonary vascular resistance and heart rate.

    Science.gov (United States)

    Vallecilla, Carolina; Khiabani, Reza H; Sandoval, Néstor; Fogel, Mark; Briceño, Juan Carlos; Yoganathan, Ajit P

    2014-06-03

    The considerable blood mixing in the bidirectional Glenn (BDG) physiology further limits the capacity of the single working ventricle to pump enough oxygenated blood to the circulatory system. This condition is exacerbated under severe conditions such as physical activity or high altitude. In this study, the effect of high altitude exposure on hemodynamics and ventricular function of the BDG physiology is investigated. For this purpose, a mathematical approach based on a lumped parameter model was developed to model the BDG circulation. Catheterization data from 39 BDG patients at stabilized oxygen conditions was used to determine baseline flows and pressures for the model. The effect of high altitude exposure was modeled by increasing the pulmonary vascular resistance (PVR) and heart rate (HR) in increments up to 80% and 40%, respectively. The resulting differences in vascular flows, pressures and ventricular function parameters were analyzed. By simultaneously increasing PVR and HR, significant changes (p fails to overcome the increased preload and implied low oxygenation in BDG patients at higher altitudes, especially for those with high baseline PVRs. The presented mathematical model provides a framework to estimate the hemodynamic performance of BDG patients at different PVR increments. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Disturbances in Maternal Steroidogenesis and Appearance of Intrauterine Growth Retardation at High-Altitude Environments Are Established from Early Pregnancy. Effects of Treatment with Antioxidant Vitamins.

    Directory of Open Access Journals (Sweden)

    Victor H Parraguez

    Full Text Available Pregnancies at high-altitudes are influenced by hypoxia and oxidative stress and frequently affected by IUGR. However, a common thought is that early pregnant women visiting altitude have no major complications for gestation development, since IUGR is developed during the second half of pregnancy. Thus, using a well-characterized sheep-model, we aimed to determine whether long- and/or short-term exposure to high-altitude may affect maternal steroidogenesis and therefore embryo-fetal growth from conception. The second aim was to differentiate the relative role of hypoxia and oxidative stress by assessing the effects of supplementation with antioxidant agents during this early-pregnancy stage, which were previously found to be useful to prevent IUGR. The results indicate that both long- and short-term exposure to high-altitude causes disturbances in maternal ovarian steroidogenesis and negatively affects embryo-fetal growth already during the very early stages of gestation, with the consequences being even worsened in newcomers to high-altitude. The supply of antioxidant during this period only showed discrete effects for preventing IUGR. In conclusion, the present study gives a warning for clinicians about the risks for early-pregnant women when visiting high-altitude regions and suggests the need for further studies on the effects of the length of exposure and on the interaction of the exposure with the pregnancy stage.

  18. Added value of far-infrared radiometry for remote sensing of ice clouds

    Science.gov (United States)

    Libois, Quentin; Blanchet, Jean-Pierre

    2017-06-01

    Several cloud retrieval algorithms based on satellite observations in the infrared have been developed in the last decades. However, these observations only cover the midinfrared (MIR, λ transparent in the FIR, using FIR channels would reduce by more than 50% the uncertainties on retrieved values of optical thickness, effective particle diameter, and cloud top altitude. Notably, this would extend the range of applicability of current retrieval methods to the polar regions and to clouds with large optical thickness, where MIR algorithms perform poorly. The high performance of solar reflection-based algorithms would thus be reached in nighttime conditions. Since the sensitivity of ice cloud thermal emission to effective particle diameter is approximately 5 times larger in the FIR than in the MIR, using FIR observations is a promising venue for studying ice cloud microphysics and precipitation processes. This is highly relevant for cirrus clouds and convective towers. This is also essential to study precipitation in the driest regions of the atmosphere, where strong feedbacks are at play between clouds and water vapor. The deployment in the near future of a FIR spaceborne radiometer is technologically feasible and should be strongly supported.

  19. Pruning management of Chardonnay grapevines at high altitude in Brazilian southeast

    Directory of Open Access Journals (Sweden)

    Tania dos Reis Mendonça

    2016-03-01

    Full Text Available ABSTRACT The agronomical responses of Chardonnay, a variety indicated for sparkling wine production, is influenced by the vineyard management and the edaphoclimatic conditions of the region. The objective of this study was to evaluate the effects of two pruning types (Royat and double Guyot on vegetative and reproductive development of Chardonnay vine growing at high altitude in the Brazilian southeastern region. The experiment was carried out in a commercial vineyard located at 1,280 m of altitude in Divinolândia, São Paulo State, Brazil. The Chardonnay vines (clone 96, grafted onto 1103 Paulsen rootstock and trained in a vertical shoot positioning trellis system, were assessed. Vegetative vigor, bud fruitfulness, production and physicochemical composition of grapes were evaluated during 2014 and 2015 growing seasons. The Royat pruning induced higher vegetative vigor and increased the bud fruitfulness, the cluster number and the productivity of Chardonnay vine when compared to Guyot pruning. Even though the increase on yield was observed, there was no effect of pruning type on grape final quality. Therefore, the choice of pruning method in function of variety genetic characteristics and their interaction with environment can optimize the vineyard profitability. In the Brazilian southeast, the Royat system is the most suitable one to grow Chardonnay for sparkling wines production.

  20. Paleo-Climate and Glaciological Reconstruction in Central Asia through the Collection and Analysis of Ice Cores and Instrumental Data from the Tien Shan

    International Nuclear Information System (INIS)

    Vladimir Aizen; Donald Bren; Karl Kreutz; Cameron Wake

    2001-01-01

    While the majority of ice core investigations have been undertaken in the polar regions, a few ice cores recovered from carefully selected high altitude/mid-to-low latitude glaciers have also provided valuable records of climate variability in these regions. A regional array of high resolution, multi-parameter ice core records developed from temperate and tropical regions of the globe can be used to document regional climate and environmental change in the latitudes which are home to the vase majority of the Earth's human population. In addition, these records can be directly compared with ice core records available from the polar regions and can therefore expand our understanding of inter-hemispheric dynamics of past climate changes. The main objectives of our paleoclimate research in the Tien Shan mountains of middle Asia combine the development of detailed paleoenvironmental records via the physical and chemical analysis of ice cores with the analysis of modern meteorological and hydrological data. The first step in this research was the collection of ice cores from the accumulation zone of the Inylchek Glacier and the collection of meteorological data from a variety of stations throughout the Tien Shan. The research effort described in this report was part of a collaborative effort with the United State Geological Survey's (USGS) Global Environmental Research Program which began studying radionuclide deposition in mid-latitude glaciers in 1995