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Sample records for altitude

  1. Fulminant high altitude blindness.

    Science.gov (United States)

    Mashkovskiy, Evgeny; Szawarski, Piotr; Ryzhkov, Pavel; Goslar, Tomaz; Mrak, Irena

    2016-06-01

    Prolonged altitude exposure even with acclimatization continues to present a physiological challenge to all organ systems including the central nervous system. We describe a case of a 41-year-old Caucasian female climber who suffered severe visual loss that was due to possible optic nerve pathology occurring during a high altitude expedition in the Himalayas. This case is atypical of classic high altitude cerebral oedema and highlights yet another danger of prolonged sojourn at extreme altitudes. PMID:27601532

  2. HIGH-ALTITUDE ILLNESS

    Directory of Open Access Journals (Sweden)

    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

  3. [Mountaineering and altitude sickness].

    Science.gov (United States)

    Maggiorini, M

    2001-06-01

    Almost every second trekker or climber develops two to three symptoms of the high altitude illness after a rapid ascent (> 300 m/day) to an altitude above 4000 m. We distinguish two forms of high altitude illness, a cerebral form called acute mountain sickness and a pulmonary form called high altitude pulmonary edema. Essentially, acute mountain sickness is self-limiting and benign. Its symptoms are mild to moderate headache, loss of appetite, nausea, dizziness and insomnia. Nausea rarely progresses to vomiting, but if it does, this may anticipate a progression of the disease into the severe form of acute mountain sickness, called high altitude cerebral edema. Symptoms and signs of high altitude cerebral edema are severe headache, which is not relieved by acetaminophen, loss of movement coordination, ataxia and mental deterioration ending in coma. The mechanisms leading to acute mountain sickness are not very well understood; the loss of cerebral autoregulation and a vasogenic type of cerebral edema are being discussed. High altitude pulmonary edema presents in roughly twenty percent of the cases with mild symptoms of acute mountain sickness or even without any symptoms at all. Symptoms associated with high altitude pulmonary edema are incapacitating fatigue, chest tightness, dyspnoe at the minimal effort that advances to dyspnoe at rest and orthopnoe, and a dry non-productive cough that progresses to cough with pink frothy sputum due to hemoptysis. The hallmark of high altitude pulmonary edema is an exaggerated hypoxic pulmonary vasoconstriction. Successful prophylaxis and treatment of high altitude pulmonary edema using nifedipine, a pulmonary vasodilator, indicates that pulmonary hypertension is crucial for the development of high altitude pulmonary edema. The primary treatment of high altitude illness consists in improving hypoxemia and acclimatization. For prophylaxis a slow ascent at a rate of 300 m/day is recommended, if symptoms persist, acetazolamide at a

  4. 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. PMID:19519223

  5. High Altitude and Heart

    OpenAIRE

    Murat Yalcin; Ejder Kardesoglu; Zafer Isilak

    2011-01-01

    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 altit...

  6. High Altitude and Heart

    Directory of Open Access Journals (Sweden)

    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

  7. Low altitude remote sensing

    NARCIS (Netherlands)

    Pérez Calero, D.; Peyaud, A.; Van der Wal, D.; van 't Hof, J.; Hakkesteegt, H.; Vink, R.; Bovenkamp, E.G.P.; van Antwerpen, G.; Meynart, R.; Neeck, S.P.; Shimoda, H.; Habib, S.

    2008-01-01

    In 2007 TNO started to fly some sensors on an unmanned helicopter platform. These sensors included RGB, B/W and thermal infrared cameras. In 2008 a spectrometer was added. The goal for 2010 is to be able to offer a low altitude flying platform including several sensors. Development of these sensors

  8. Cerebrovascular stroke at high altitude

    International Nuclear Information System (INIS)

    Objective: To asses the high altitude as a risk factor for cerebrovascular stroke in people residing at a height greater than 15,000 feet above sea level. Results: Ten patients suffered from stroke at high altitude while just one case had stroke in indexed age group at lower heights (p-value<0.05). Relative risk was 10 times greater at high altitude. Conclusion: High altitude is a risk factor for stroke in persons residing at altitudes of over 15, 000 ft. (author)

  9. Brain Food at High Altitude.

    Science.gov (United States)

    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. PMID:27651260

  10. Brain Food at High Altitude.

    Science.gov (United States)

    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.

  11. Cardiovascular physiology at high altitude.

    Science.gov (United States)

    Hooper, T; Mellor, A

    2011-03-01

    The role of the cardiovascular system is to deliver oxygenated blood to the tissues and remove metabolic effluent. It is clear that this complex system will have to adapt to maintain oxygen deliver in the profound hypoxia of high altitude. The literature on the adaptation of both the systemic and pulmonary circulations to high altitude is reviewed.

  12. Asteroid airburst altitude vs. strength

    Science.gov (United States)

    Robertson, Darrel; Wheeler, Lorien; Mathias, Donovan

    2016-10-01

    Small NEO asteroids (plans and emergency management.Strong asteroids, such as a monolithic boulder, fail and create peak energy deposition close to the altitude at which ram dynamic pressure exceeds the material cohesive strength. Weaker asteroids, such as a rubble pile, structurally fail at higher altitude, but it requires the increased aerodynamic pressure at lower altitude to disrupt and disperse the rubble. Consequently the resulting airbursts have a peak energy deposition at similar altitudes.In this study hydrocode simulations of the entry and break-up of small asteroids were performed to examine the effect of strength, size, composition, entry angle, and speed on the resulting airburst. This presentation will show movies of the simulations, the results of peak burst height, and the comparison to semi-analytical models.

  13. Venus Altitude Cycling Balloon Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The ISTAR Group ( IG) and team mate Thin Red Line Aerospace (TRLA) propose a Venus altitude cycling balloon (Venus ACB), an innovative superpressure balloon...

  14. High-altitude pulmonary hypertension

    Directory of Open Access Journals (Sweden)

    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.

  15. Hormonal Changes Under Altitude Stress

    Directory of Open Access Journals (Sweden)

    H.D Brahmachari

    1977-04-01

    Full Text Available The separate effects of exposure for six hours to cold (8 degree Celsius, hypoxia (4267 m. and simulated altitude (8 degree Celsius at 4267 m.have been studied on ten human subjects in a decompression chamber, with respect to the changes in blood cortisol, ADH and urinary catecholamines. Changes in blood cortisol, PBI, ADH urinary excretion of 17-keto steroids and urine volume have been recorded on another ten subjects on acute exposure to high altitude (3505 m.. Changes in the same parameters alongwith urinary testosterone level, have been recorded on another 20 subjects on prolonged exposure for two years to high altitude (3505 m.. The results have been discussed.

  16. Sleep and Breathing at High Altitude.

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    Wickramasinghe, Himanshu; Anholm, James D.

    1999-01-01

    Sleep at high altitude is characterized by poor subjective quality, increased awakenings, frequent brief arousals, marked nocturnal hypoxemia, and periodic breathing. A change in sleep architecture with an increase in light sleep and decreasing slow-wave and REM sleep have been demonstrated. Periodic breathing with central apnea is almost universally seen amongst sojourners to high altitude, although it is far less common in long-standing high altitude dwellers. Hypobaric hypoxia in concert with periodic breathing appears to be the principal cause of sleep disruption at altitude. Increased sleep fragmentation accounts for the poor sleep quality and may account for some of the worsened daytime performance at high altitude. Hypoxic sleep disruption contributes to the symptoms of acute mountain sickness. Hypoxemia at high altitude is most severe during sleep. Acetazolamide improves sleep, AMS symptoms, and hypoxemia at high altitude. Low doses of a short acting benzodiazepine (temazepam) may also be useful in improving sleep in high altitude. PMID:11898114

  17. Altitude, Acute Mountain Sickness and Headache

    Science.gov (United States)

    ... Follow us on Instagram DONATE TODAY Altitude, Acute Mountain Sickness and Headache Abuse, Maltreatment, and PTSD and Their Relationship to Migraine Altitude, Acute Mountain Sickness and Headache Alcohol and Migraine Anxiety and ...

  18. Cold Stress at High Altitudes

    Directory of Open Access Journals (Sweden)

    N. C. Majumdar

    1983-04-01

    Full Text Available The problem of cold at high altitudes has been analysed from a purely physical standpoint. It has been shown that Siple's Wind-Chill Index is not reliable because (i it does not make use of the well established principles governing the physical processes of heat transfer by convection and radiation, and (ii it assumes that the mean radiant temperature of the surroundings is the same as the ambient dry bulb temperature. A Cold Stress Index has been proposed which is likely to be a more reliable guide for assessing the climatic hazards of high altitude environments. The Index can be quickly estimated with the help of two nomograms devised for the purpose.

  19. Rocket Engine Altitude Simulation Technologies

    Science.gov (United States)

    Woods, Jody L.; Lansaw, John

    2010-01-01

    John C. Stennis Space Center is embarking on a very ambitious era in its rocket engine propulsion test history. The first new large rocket engine test stand to be built at Stennis Space Center in over 40 years is under construction. The new A3 Test Stand is designed to test very large (294,000 Ibf thrust) cryogenic propellant rocket engines at a simulated altitude of 100,000 feet. A3 Test Stand will have an engine testing chamber where the engine will be fired after the air in the chamber has been evacuated to a pressure at the simulated altitude of less than 0.16 PSIA. This will result in a very unique environment with extremely low pressures inside a very large chamber and ambient pressures outside this chamber. The test chamber is evacuated of air using a 2-stage diffuser / ejector system powered by 5000 lb/sec of steam produced by 27 chemical steam generators. This large amount of power and flow during an engine test will result in a significant acoustic and vibrational environment in and around A3 Test Stand.

  20. Economy of Adaptation to High Altitude

    Institute of Scientific and Technical Information of China (English)

    Jean-Paul Richalet

    2004-01-01

    @@ The international meeting that will be held in Xining and Lhasa in August 2004 will be a wonderful occasion to share facts and concepts dealing with adaptation to high altitude. Life at high altitude is a challenge for thousands of animal species and millions of humans residing or visiting high altitude regions of the world. To try to understand the physiological mechanisms involved in the adaptation processes to high altitude hypoxia, it is convenient to start by defining what is "extreme" from a biological point of view.

  1. Aspirated Compressors for High Altitude Engines Project

    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...

  2. Jupiter's High-Altitude Clouds

    Science.gov (United States)

    2007-01-01

    The New Horizons Multispectral Visible Imaging Camera (MVIC) snapped this incredibly detailed picture of Jupiter's high-altitude clouds starting at 06:00 Universal Time on February 28, 2007, when the spacecraft was only 2.3 million kilometers (1.4 million miles) from the solar system's largest planet. Features as small as 50 kilometers (30 miles) are visible. The image was taken through a narrow filter centered on a methane absorption band near 890 nanometers, a considerably redder wavelength than what the eye can see. Images taken through this filter preferentially pick out clouds that are relatively high in the sky of this gas giant planet because sunlight at the wavelengths transmitted by the filter is completely absorbed by the methane gas that permeates Jupiter's atmosphere before it can reach the lower clouds. The image reveals a range of diverse features. The south pole is capped with a haze of small particles probably created by the precipitation of charged particles into the polar regions during auroral activity. Just north of the cap is a well-formed anticyclonic vortex with rising white thunderheads at its core. Slightly north of the vortex are the tendrils of some rather disorganized storms and more pinpoint-like thunderheads. The dark 'measles' that appear a bit farther north are actually cloud-free regions where light is completely absorbed by the methane gas and essentially disappears from view. The wind action considerably picks up in the equatorial regions where giant plumes are stretched into a long wave pattern. Proceeding north of the equator, cirrus-like clouds are shredded by winds reaching speeds of up to 400 miles per hour, and more pinpoint-like thunderheads are visible. Although some of the famous belt and zone structure of Jupiter's atmosphere is washed out when viewed at this wavelength, the relatively thin North Temperate Belt shows up quite nicely, as does a series of waves just north of the belt. The north polar region of Jupiter in

  3. Delayed appearance of high altitude retinal hemorrhages.

    Directory of Open Access Journals (Sweden)

    Daniel Barthelmes

    Full Text Available BACKGROUND: Retinal hemorrhages have been described as a component of high altitude retinopathy (HAR in association with altitude illness. In this prospective high altitude study, we aimed to gain new insights into the pathophysiology of HAR and explored whether HAR could be a valid early indicator of altitude illness. METHODOLOGY/PRINCIPAL FINDINGS: 28 mountaineers were randomly assigned to two ascent profiles during a research expedition to Mt. Muztagh Ata (7546 m/24,751 ft. Digital fundus photographs were taken prior to expedition at 490 m (1,607 ft, during expedition at 4497 m (14,750 ft = base camp, 5533 m (18,148 ft, 6265 m (20,549 ft, 6865 m (22,517 ft and 4.5 months thereafter at 490 m. Number, size and time of occurrence of hemorrhages were recorded. Oxygen saturation (SpO₂ and hematocrit were also assessed. 79% of all climbers exhibited retinal hemorrhages during the expedition. Number and area of retinal bleeding increased moderately to medium altitudes (6265 m. Most retinal hemorrhages were detected after return to base camp from a high altitude. No post-expeditional ophthalmic sequelae were detected. Significant negative (SpO₂ Beta: -0.4, p<0.001 and positive (hematocrit Beta: 0.2, p = 0.002, time at altitude Beta: 0.33, p = 0.003 correlations with hemorrhages were found. CONCLUSIONS/SIGNIFICANCE: When closely examined, a very large amount of climbers exhibit retinal hemorrhages during exposure to high altitudes. The incidence of retinal hemorrhages may be greater than previously appreciated as a definite time lag was observed between highest altitude reached and development of retinal bleeding. Retinal hemorrhages should not be considered warning signs of impending severe altitude illness due to their delayed appearance.

  4. High altitude aircraft flight tests

    Science.gov (United States)

    Helmken, Henry; Emmons, Peter; Homeyer, David

    1996-03-01

    In order to make low earth orbit L-band propagation measurements and test new voice communication concepts, a payload was proposed and accepted for flight aboard the COMET (now METEOR) spacecraft. This Low Earth Orbiting EXperiment payload (LEOEX) was designed and developed by Motorola Inc. and sponsored by the Space Communications Technology Center (SCTC), a NASA Center for the Commercial Development of Space (CCDS) located at Florida Atlantic University. In order to verify the LEOEX payload for satellite operation and obtain some preliminary propagation data, a series of 9 high altitude aircraft (SR-71 and ER-2) flight tests were conducted. These flights took place during a period of 7 months, from October 1993 to April 1994. This paper will summarize the operation of the LEOEX payload and the particular configuration used for these flights. The series of flyby tests were very successful and demonstrated how bi-directional, Time Division Multiple Access (TDMA) voice communication will work in space-to-ground L-band channels. The flight tests also acquired propagation data which will be representative of L-band Low Earth Orbiting (LEO) communication systems. In addition to verifying the LEOEX system operation, it also uncovered and ultimately aided the resolution of several key technical issues associated with the payload.

  5. [Sildenafil and exercise performance at altitude].

    Science.gov (United States)

    Peidro, Roberto M

    2015-01-01

    Barometric pressure and partial oxygen pressure decrease with increasing altitude. Hypobaric hypoxia produced is responsible for altitude-related diseases and it can cause severe decrements in exercise performance. The physiological adaptations to the altitude are multiple and they contribute to alter different athletic qualities. The VO2 worsening could be associated to increased pulmonary vascular resistance and nitric oxide diffusion alteration. Performance impairments at altitude can also be accentuated by hypoxia-induced elevations in pulmonary arterial pressure. Clinical studies have demonstrated the beneficial effects of sildenafil on the treatment of pulmonary hypertension. These effects have led to suggest that its indication for competitions at altitude might improve athletic performance. The investigations demonstrate different results depending on the altitude level and times and intensities of exercise. Some studies show performance improvements, although not in all participants. Individual responses vary widely between different athletes. This presentation examines the effects of altitude on exercise capacity and shows studies about the use of sildenafil to improve sport performance. This text also discusses the possible side effects and implications for the use of sildenafil in athletes, indication that is not the basic one of the drug. The physicians must know in each athlete the individual sildenafil side effects that could arise and that would influence negatively on health and performance. PMID:26339884

  6. 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...

  7. Python Engine Installed in Altitude Wind Tunnel

    Science.gov (United States)

    1949-01-01

    An engine mechanic checks instrumentation prior to an investigation of engine operating characteristics and thrust control of a large turboprop engine with counter-rotating propellers under high-altitude flight conditions in the 20-foot-dianieter test section of the Altitude Wind Tunnel at the Lewis Flight Propulsion Laboratory of the National Advisory Committee for Aeronautics, Cleveland, Ohio, now known as the John H. Glenn Research Center at Lewis Field.

  8. Child health and living at high altitude.

    Science.gov (United States)

    Niermeyer, S; Andrade Mollinedo, P; Huicho, L

    2009-10-01

    The health of children born and living at high altitude is shaped not only by the low-oxygen environment, but also by population ancestry and sociocultural determinants. High altitude and the corresponding reduction in oxygen delivery during pregnancy result in lower birth weight with higher elevation. Children living at high elevations are at special risk for hypoxaemia during infancy and during acute lower respiratory infection, symptomatic high-altitude pulmonary hypertension, persistence of fetal vascular connections, and re-entry high-altitude pulmonary oedema. However, child health varies from one population group to another due to genetic adaptation as well as factors such as nutrition, intercurrent infection, exposure to pollutants and toxins, socioeconomic status, and access to medical care. Awareness of the risks uniquely associated with living at high altitude and monitoring of key health indicators can help protect the health of children at high altitude. These considerations should be incorporated into the scaling-up of effective interventions for improving global child health and survival. PMID:19066173

  9. 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.

  10. Neutral Wind Observations below 200 km altitudes

    Science.gov (United States)

    Watanabe, S.; Abe, T.; Habu, H.; Kakinami, Y.; Larsen, M. F.; Pfaff, R. F., Jr.; Yamamoto, M.

    2015-12-01

    Neutral Wind Observations below 200 km altitudesS. Watanabe1, T. Abe2, H. Habu2, Y. Kakinami3, M. Larsen4, R. Pfaff5, M. Yamamoto6, M-Y. Yamamoto31Hokkaido University/Hokkaido Information University, 2JAXA/ISAS, 3Kochi University of Technology, 4Clemson University, 5NASA/Goddard Space Flight Center, 6Kyoto University, Neutral wind in the thermosphere is one of the key parameters to understand the ionosphere-thermosphere coupling process. JAXA/ISAS successfully launched sounding rockets from Uchinoura Space Center (USC) on September 2, 2007, January 12, 2012, and July 20, 2013, and NASA launched sounding rockets from Kwajalein on May 7, 2013 and from Wallops on July 4, 2013. The rockets installed Lithium and/or TMA canisters as well as instruments for plasma and electric and magnetic fields. The atomic Lithium gases were released at altitudes between 150 km and 300 km in the evening on September 2, 2007, at altitude of ~100 km in the morning on January 12, 2012, at altitude of ~120km in the midnight on July 20, 2013, at altitude between 150 km and 300 km in the evening on May 7, 2013 and at altitude of ~150 km in the noon on July 4, 2013. The Lithium atoms were scattering sunlight by resonance scattering with wavelength of 670nm. However, the Lithium atoms scattered moon light on July 20, 2013. The moon light scattering is the first time to use for thermospheric wind measurement in the midnight. The Lithium clouds/trails and TMA trails showed clearly the neutral wind shears and atmospheric waves at ~150 km altitude in the lower thermosphere for all local time.

  11. Patients with Obstructive Sleep Apnea at Altitude.

    Science.gov (United States)

    Bloch, Konrad E; Latshang, Tsogyal D; Ulrich, Silvia

    2015-06-01

    Bloch, Konrad E., Tsogyal D. Latshang, and Silvia Ulrich. Patients with obstructive sleep apnea at altitude. High Alt Med Biol 16:110-116, 2015.--Obstructive sleep apnea (OSA) is highly prevalent in the general population, in particular in men and women of older age. In OSA patients sleeping near sea level, the apneas/hypopneas associated with intermittent hypoxemia are predominantly due to upper airway collapse. When OSA patients stay at altitudes above 1600 m, corresponding to that of many tourist destinations, hypobaric hypoxia promotes frequent central apneas in addition to obstructive events, resulting in combined intermittent and sustained hypoxia. This induces strong sympathetic activation with elevated heart rate, cardiac arrhythmia, and systemic hypertension. There are concerns that these changes expose susceptible OSA patients, in particular those with advanced age and co-morbidities, to an excessive risk of cardiovascular and other adverse events during a stay at altitude. Based on data from randomized trials, it seems advisable for OSA patients to use continuous positive airway pressure treatment with computer controlled mask pressure adjustment (autoCPAP) in combination with acetazolamide during an altitude sojourn. If CPAP therapy is not feasible, acetazolamide alone is better than no treatment at all, as it improves oxygenation and sleep apnea and prevents excessive blood pressure rises of OSA patients at altitude. PMID:25973669

  12. 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.

  13. Responses of the autonomic nervous system in altitude adapted and high altitude pulmonary oedema subjects

    Science.gov (United States)

    Mathew, Lazar; Purkayastha, S. S.; Jayashankar, A.; Radhakrishnan, U.; Sen Gupta, J.; Nayar, H. S.

    1985-06-01

    Studies were carried out to ascertain the role of sympatho-parasympathetic responses in the process of adaptation to altitude. The assessment of status of autonomic balance was carried out in a group of 20 young male subjects by recording their resting heart rate, blood pressure, oral temperature, mean skin temperature, extremity temperatures, pupillary diameter, cold pressor response, oxygen consumption, cardioacceleration during orthostasis and urinary excretion of catecholamines; in a thermoneutral laboratory. The same parameters were repeated on day 3 and at weekly intervals for a period of 3 weeks, after exposing them to 3,500 m; and also after return to sea level. At altitude, similar studies were carried out in a group of 10 acclimatized lowlanders, 10 high altitude natives and 6 patients who had recently recovered from high altitude pulmonary oedema. In another phase, similar studies were done in two groups of subjects, one representing 15 subjects who had stayed at altitude (3,500 4,000 m) without any ill effects and the other comprising of 10 subjects who had either suffered from high altitude pulmonary oedema (HAPO) or acute mountain sickness (AMS). The results revealed sympathetic overactivity on acute induction to altitude which showed gradual recovery on prolonged stay, the high altitude natives had preponderance to parasympathetic system. Sympathetic preponderance may not be an essential etiological factor for the causation of maladaptation syndromes.

  14. Sleep of Andean high altitude natives.

    Science.gov (United States)

    Coote, J H; Stone, B M; Tsang, G

    1992-01-01

    The structure of sleep in lowland visitors to altitudes greater than 4000 m is grossly disturbed. There are no data on sleep in long-term residents of high altitudes. This paper describes an electroencephalographic study of sleep in high altitude dwellers who were born in and are permanent residents of Cerro de Pasco in the Peruvian Andes, situated at 4330 m. Eight healthy male volunteers aged between 18 and 69 years were studied. Sleep was measured on three consecutive nights for each subject. Electroencephalographs, submental electromyographs and electro-oculograms were recorded. Only data from the third night were used in the analysis. The sleep patterns of these subjects resembled the normal sleep patterns described by others in lowlanders at sea level. There were significant amounts of slow wave sleep in the younger subjects and rapid eye movement sleep seemed unimpaired.

  15. High-altitude physiology: lessons from Tibet

    Science.gov (United States)

    Wagner, Peter D.; Simonson, Tatum S.; Wei, Guan; Wagner, Harrieth; Wuren, Tanna; Yan, Ma; Qin, Ga; Ge, Rili

    2013-05-01

    Polycythemia is a universal lowlander response to altitude; healthy Andean high-altitude natives also have elevated [Hb]. While this may enhance O2 transport to tissues, studies have shown that acute isovolumic changes in [Hb] do not affect exercise capacity. Many high-altitude Tibetans have evolved sea-level values of [Hb], providing a natural opportunity to study this issue. In 21 young healthy male Tibetans with [Hb] between 15 and 23 g/dl, we measured VO2MAX and O2 transport capacity at 4200m. VO2MAX was higher when [Hb] was lower (Pcardiac output and muscle O2 diffusional conductance, but neither ventilation nor the alveolar-arterial PO2 difference (AaPO2) varied with [Hb]. In contrast, Andean high altitude natives remain polycythemic with larger lungs and higher lung diffusing capacity, a smaller exercising AaPO2, and lower ventilation. The challenges now are (1) to understand the different adaptive pathways used by Andeans and Tibetans, and (2) to determine in Tibetans whether, during evolution, reduced [Hb] appeared first, causing compensatory cardiac and muscle adaptations, or if enhanced cardiac function and muscle O2 transport capacity appeared first, permitting secondary reduction in [Hb]. For (2), further research is necessary to determine the basis of enhanced cardiac function and muscle O2 transport, and identify molecular targets of evolution in heart and muscle. Putative mutations can then be timed and compared to appearance of those affecting [Hb].

  16. Dietary Recommendations for Cyclists during Altitude Training

    Directory of Open Access Journals (Sweden)

    Małgorzata Michalczyk

    2016-06-01

    Full Text Available 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.

  17. 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

  18. 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.

  19. Estimation of high altitude Martian dust parameters

    Science.gov (United States)

    Pabari, Jayesh; Bhalodi, Pinali

    2016-07-01

    Dust devils are known to occur near the Martian surface mostly during the mid of Southern hemisphere summer and they play vital role in deciding background dust opacity in the atmosphere. The second source of high altitude Martian dust could be due to the secondary ejecta caused by impacts on Martian Moons, Phobos and Deimos. Also, the surfaces of the Moons are charged positively due to ultraviolet rays from the Sun and negatively due to space plasma currents. Such surface charging may cause fine grains to be levitated, which can easily escape the Moons. It is expected that the escaping dust form dust rings within the orbits of the Moons and therefore also around the Mars. One more possible source of high altitude Martian dust is interplanetary in nature. Due to continuous supply of the dust from various sources and also due to a kind of feedback mechanism existing between the ring or tori and the sources, the dust rings or tori can sustain over a period of time. Recently, very high altitude dust at about 1000 km has been found by MAVEN mission and it is expected that the dust may be concentrated at about 150 to 500 km. However, it is mystery how dust has reached to such high altitudes. Estimation of dust parameters before-hand is necessary to design an instrument for the detection of high altitude Martian dust from a future orbiter. In this work, we have studied the dust supply rate responsible primarily for the formation of dust ring or tori, the life time of dust particles around the Mars, the dust number density as well as the effect of solar radiation pressure and Martian oblateness on dust dynamics. The results presented in this paper may be useful to space scientists for understanding the scenario and designing an orbiter based instrument to measure the dust surrounding the Mars for solving the mystery. The further work is underway.

  20. Can aneroid sphygmomanometers be used at altitude?

    Science.gov (United States)

    Kametas, N A; McAuliffe, F; Krampl, E; Nicolaides, K H; Shennan, A H

    2006-07-01

    Mercury-independent devices are increasingly being used in clinical practice as mercury will soon be removed from clinical use as a result of environmental, health and safety concerns. The aim of this study was to evaluate the accuracy of a portable aneroid device in an adult population at high altitude by following the part of the protocol of the British Hypertension Society regarding comparison between device and observer. We examined 10 subjects in Cerro de Pasco, Peru, which is situated 4370 m above sea level. The aneroid device was initially calibrated at both high altitude and at sea level to ensure optimal function. Validation of the device was undertaken at high altitude by connecting it in parallel to two mercury sphygmomanometers. Eleven sequential same-arm measurements were taken from each subject by two trained observers, alternating between mercury sphygmomanometry and the aneroid device. Simultaneous mercury readings were also recorded for additional analysis. During calibration, all 60 comparisons between the aneroid and mercury sphygmomanometers were within 3 mm Hg both at sea level and at high altitude. At validation, the device achieved an A grade for both systolic and diastolic pressures and also fulfilled the requirements of the Association for the Advancement of Medical Instrumentation. The mean and standard deviation for systolic and diastolic pressures, respectively, were -1.32 (4.3) mm Hg and 3.7 (4.7) mm Hg in sequential analysis and -0.7 (2.6) mm Hg and -3.3 (2.7) mm Hg in simultaneous analysis. We conclude that the Riester-Exacta portable aneroid device can be recommended for use in an adult population at high altitude.

  1. Why Are High-Altitude Natives So Strong at Altitude? Maximal Oxygen Transport to the Muscle Cell in Altitude Natives.

    Science.gov (United States)

    Lundby, Carsten; Calbet, Jose A L

    2016-01-01

    In hypoxia aerobic exercise performance of high-altitude natives is suggested to be superior to that of lowlanders; i.e., for a given altitude natives are reported to have higher maximal oxygen uptake (VO2max). The likely basis for this is a higher pulmonary diffusion capacity, which in turn ensures higher arterial O2 saturation (SaO2) and therefore also potentially a higher delivery of O2 to the exercising muscles. This review focuses on O2 transport in high-altitude Aymara. We have quantified femoral artery O2 delivery, arterial O2 extraction and calculated leg VO2 in Aymara, and compared their values with that of acclimatizing Danish lowlanders. All subjects were studied at 4100 m. At maximal exercise SaO2 dropped tremendously in the lowlanders, but did not change in the Aymara. Therefore arterial O2 content was also higher in the Aymara. At maximal exercise however, fractional O2 extraction was lower in the Aymara, and the a-vO2 difference was similar in both populations. The lower extraction levels in the Aymara were associated with lower muscle O2 conductance (a measure of muscle diffusion capacity). At any given submaximal exercise intensity, leg VO2 was always of similar magnitude in both groups, but at maximal exercise the lowlanders had higher leg blood flow, and hence also higher maximum leg VO2. With the induction of acute normoxia fractional arterial O2 extraction fell in the highlanders, but remained unchanged in the lowlanders. Hence high-altitude natives seem to be more diffusion limited at the muscle level as compared to lowlanders. In conclusion Aymara preserve very high SaO2 during hypoxic exercise (likely due to a higher lung diffusion capacity), but the effect on VO2max is reduced by a lower ability to extract O2 at the muscle level. PMID:27343089

  2. [Effect of altitude on iron absorption].

    Science.gov (United States)

    Pizarro, F; Zavaleta, N; Hertrampf, E; Berlanga, R; Camborda, L; Olivares, M

    1998-03-01

    Iron bioavailability was evaluated in people living in high altitudes. Absorption was estimated from a reference dose of ferrous ascorbate and from a standard diet of wheat flour, using extrinsic tag radioisotope technique of 55Fe and 59Fe. Twenty four volunteers, healthy women, with ages ranging from 28 to 45 years, participated. Of those, eleven lived at 3450 meters above sea level (m.a.s.l.) in Huancayo city-Peru (study group), and 13 lived in Santiago de Chile at 630 m.a.s.l. (control group). Iron absorption from reference dose of ferrous ascorbate was 32.0% and 31.1% in the study and control groups respectively. The geometric mean of iron absorption from the standard diet, corrected to 40% of absorption of reference dose, was 9.0% and 6.9% in the study and control groups respectively (NS). The results suggest that altitude does not produce a high iron absorption in highlander residents.

  3. Dust observations at orbital altitudes surrounding Mars.

    Science.gov (United States)

    Andersson, L; Weber, T D; Malaspina, D; Crary, F; Ergun, R E; Delory, G T; Fowler, C M; Morooka, M W; McEnulty, T; Eriksson, A I; Andrews, D J; Horanyi, M; Collette, A; Yelle, R; Jakosky, B M

    2015-11-01

    Dust is common close to the martian surface, but no known process can lift appreciable concentrations of particles to altitudes above ~150 kilometers. We present observations of dust at altitudes ranging from 150 to above 1000 kilometers by the Langmuir Probe and Wave instrument on the Mars Atmosphere and Volatile Evolution spacecraft. Based on its distribution, we interpret this dust to be interplanetary in origin. A comparison with laboratory measurements indicates that the dust grain size ranges from 1 to 12 micrometers, assuming a typical grain velocity of ~18 kilometers per second. These direct observations of dust entering the martian atmosphere improve our understanding of the sources, sinks, and transport of interplanetary dust throughout the inner solar system and the associated impacts on Mars's atmosphere.

  4. Dust observations at orbital altitudes surrounding Mars.

    Science.gov (United States)

    Andersson, L; Weber, T D; Malaspina, D; Crary, F; Ergun, R E; Delory, G T; Fowler, C M; Morooka, M W; McEnulty, T; Eriksson, A I; Andrews, D J; Horanyi, M; Collette, A; Yelle, R; Jakosky, B M

    2015-11-01

    Dust is common close to the martian surface, but no known process can lift appreciable concentrations of particles to altitudes above ~150 kilometers. We present observations of dust at altitudes ranging from 150 to above 1000 kilometers by the Langmuir Probe and Wave instrument on the Mars Atmosphere and Volatile Evolution spacecraft. Based on its distribution, we interpret this dust to be interplanetary in origin. A comparison with laboratory measurements indicates that the dust grain size ranges from 1 to 12 micrometers, assuming a typical grain velocity of ~18 kilometers per second. These direct observations of dust entering the martian atmosphere improve our understanding of the sources, sinks, and transport of interplanetary dust throughout the inner solar system and the associated impacts on Mars's atmosphere. PMID:26542578

  5. Dust observations at orbital altitudes surrounding Mars

    Science.gov (United States)

    Andersson, L.; Weber, T. D.; Malaspina, D.; Crary, F.; Ergun, R. E.; Delory, G. T.; Fowler, C. M.; Morooka, M. W.; McEnulty, T.; Eriksson, A. I.; Andrews, D. J.; Horanyi, M.; Collette, A.; Yelle, R.; Jakosky, B. M.

    2015-11-01

    Dust is common close to the martian surface, but no known process can lift appreciable concentrations of particles to altitudes above ~150 kilometers. We present observations of dust at altitudes ranging from 150 to above 1000 kilometers by the Langmuir Probe and Wave instrument on the Mars Atmosphere and Volatile Evolution spacecraft. Based on its distribution, we interpret this dust to be interplanetary in origin. A comparison with laboratory measurements indicates that the dust grain size ranges from 1 to 12 micrometers, assuming a typical grain velocity of ~18 kilometers per second. These direct observations of dust entering the martian atmosphere improve our understanding of the sources, sinks, and transport of interplanetary dust throughout the inner solar system and the associated impacts on Mars’s atmosphere.

  6. Predator foraging altitudes reveal the structure of aerial insect communities

    OpenAIRE

    Helms, Jackson A.; Aaron P. Godfrey; Tayna Ames; Bridge, Eli S.

    2016-01-01

    The atmosphere is populated by a diverse array of dispersing insects and their predators. We studied aerial insect communities by tracking the foraging altitudes of an avian insectivore, the Purple Martin (Progne subis). By attaching altitude loggers to nesting Purple Martins and collecting prey delivered to their nestlings, we determined the flight altitudes of ants and other insects. We then tested hypotheses relating ant body size and reproductive ecology to flight altitude. Purple Martins...

  7. Pulmonary embolism in young natives of high altitude

    Directory of Open Access Journals (Sweden)

    Sanjay Singhal

    2016-01-01

    Full Text Available Thrombotic events are relatively common in high altitude areas and known to occur in young soldiers working at high altitude without usual risk factors associated with thrombosis at sea-level. However, till now, cases with thrombotic events were reported only in lowlanders staying at high altitude. These two cases of pulmonary embolism demonstrate that thrombotic events can occur in highlanders after a prolonged stay at the extreme altitude.

  8. Neutral Barium Cloud Evolution at Different Altitudes

    Institute of Scientific and Technical Information of China (English)

    李磊; 徐荣栏

    2002-01-01

    Considering the joint effects of diffusion, collision, oxidation and photoionization, we study the evolution of the barium cloud at different altitudes in the space plasma active experiment. The results present the variation of the loss rate, number density distribution and brightness of the barium cloud over the range from 120 to 260km.This can be divided into oxidation, oxidation plus photoionization and photoionization regions.

  9. Cardiovascular Response to High Altitude Hypoxia

    OpenAIRE

    Manchanda, S C

    1984-01-01

    Normal and abnormal cardiovascular response to high altitude (HA) hypoxia were studied in 98 healthy subjects and in 15 patients with HA pulmonary oedema (HAPO) and acute mountain sickness (AMS) at an altitudeof 3,658 m. The healthy sea level (SL) residents showed marked blood volume changes during the first week with pulmonary hypotension and depression of left ventricular (LV) performance and physical work capacity (PWC). The HA natives, however, had better LV performance and PWC indicating...

  10. Central Sleep Apnea at High Altitude.

    Science.gov (United States)

    Burgess, Keith R; Ainslie, Philip N

    2016-01-01

    The discovery of central sleep apnea (CSA) at high altitude is usually attributed to Angelo Mosso who published in 1898. It can occur in susceptible individuals at altitude above 2000 m, but at very high altitude, say above 5000 m, it will occur in most subjects. Severity is correlated with ventilatory responsiveness, particularly to hypoxia. Theoretically, it should spontaneously improve with time and acclimatization. Although the time course of resolution is not well described, it appears to persist for more than a month at 5000 m.It occurs due to the interaction of hypocapnia with stages 1 and 2 NREM sleep, in the presence of increased loop-gain. The hypocapnia is secondary to hypoxic ventilatory drive. With acclimatization, one might expect that the increase in PaO2 and cerebral blood flow (CBF) would mitigate the CSA. However, over time, both the hypoxic and hypercapnic ventilatory responses increase, causing an increase in loop gain which is a counteracting force.The severity of the CSA can be reduced by descent, supplemental oxygen therapy, oral or intravenous acetazolamide. Recent studies suggest that acute further increases in cerebral blood flow will substantially, but temporarily, reduce central sleep apnea, without altering acid based balance. Very recently, bi-level noninvasive ventilation has also been shown to help (mechanism unknown). Sleep quality can be improved independent of the presence of CSA by the use of benzodiazepine sedation. PMID:27343103

  11. The effect of altitude hypoxia on glucose homeostasis in men

    DEFF Research Database (Denmark)

    Larsen, J J; Hansen, J M; Olsen, Niels Vidiendal;

    1997-01-01

    1. Exposure to altitude hypoxia elicits changes in glucose homeostasis with increases in glucose and insulin concentrations within the first few days at altitude. Both increased and unchanged hepatic glucose production (HGP) have previously been reported in response to acute altitude hypoxia...

  12. Nutritional Aspects of High Altitude and Snow Bound Areas

    OpenAIRE

    K. Sridharan; R. M. Rai

    1984-01-01

    The precise nutritional requirement of humans at high altitude area is not well defined. Further there are many conflicting reports on the effects of hypoxia on digestion, absorption and utilization of food at high altitude. In this review the nutritional requirements at high altitude and the effects of hypoxia on humans in relation to nutrition have been discussed.

  13. Nutritional Aspects of High Altitude and Snow Bound Areas

    Directory of Open Access Journals (Sweden)

    K. Sridharan

    1984-10-01

    Full Text Available The precise nutritional requirement of humans at high altitude area is not well defined. Further there are many conflicting reports on the effects of hypoxia on digestion, absorption and utilization of food at high altitude. In this review the nutritional requirements at high altitude and the effects of hypoxia on humans in relation to nutrition have been discussed.

  14. Altitude Testing of Large Liquid Propellant Engines

    Science.gov (United States)

    Maynard, Bryon T.; Raines, Nickey G.

    2010-01-01

    The National Aeronautics and Space Administration entered a new age on January 14, 2004 with President Bush s announcement of the creation the Vision for Space Exploration that will take mankind back to the Moon and on beyond to Mars. In January, 2006, after two years of hard, dedicated labor, engineers within NASA and its contractor workforce decided that the J2X rocket, based on the heritage of the Apollo J2 engine, would be the new engine for the NASA Constellation Ares upper stage vehicle. This engine and vehicle combination would provide assured access to the International Space Station to replace that role played by the Space Shuttle and additionally, would serve as the Earth Departure Stage, to push the Crew Excursion Vehicle out of Earth Orbit and head it on a path for rendezvous with the Moon. Test as you fly, fly as you test was chosen to be the guiding philosophy and a pre-requisite for the engine design, development, test and evaluation program. An exhaustive survey of national test facility assets proved the required capability to test the J2X engine at high altitude for long durations did not exist so therefore, a high altitude/near space environment testing capability would have to be developed. After several agency concepts the A3 High Altitude Testing Facility proposal was selected by the J2X engine program on March 2, 2007 and later confirmed by a broad panel of NASA senior leadership in May 2007. This facility is to be built at NASA s John C. Stennis Space Center located near Gulfport, Mississippi. 30 plus years of Space Shuttle Main Engine development and flight certification testing makes Stennis uniquely suited to support the Vision For Space Exploration Return to the Moon. Propellant handling infrastructure, engine assembly facilities, a trained and dedicated workforce and a broad and varied technical support base will all ensure that the A3 facility will be built on time to support the schedule needs of the J2X engine and the ultimate flight

  15. High altitude balloon experiments at IIA

    Science.gov (United States)

    Nayak, Akshata; Sreejith, A. G.; Safonova, Margarita; Murthy, Jayant

    Recent advances in balloon experiments as well as in electronics have made it possible to fly scientific payloads at costs accessible to university departments. We have begun a program of high altitude ballooning at the Indian Institute of Astrophysics, Bengaluru. The primary purpose of this activity is to test low-cost ultraviolet (UV) payloads for eventual space flight, but we will also try scientific exploration of the phenomena occurring in the upper atmosphere, including sprites and meteorite impacts. We present the results of the initial experiments carried out at the CREST campus of IIA, Hosakote, and describe our plans for the future.

  16. Auroral ion outflow: low altitude energization

    OpenAIRE

    Lynch, K.A.; Semeter, J. L.; Zettergren, M.; Kintner, P.; R. Arnoldy; Klatt, E.; J. LaBelle; Michell, R. G.; Macdonald, E. A.; Samara, M.

    2007-01-01

    International audience; The SIERRA nightside auroral sounding rocket made observations of the origins of ion upflow, at topside F-region altitudes (below 700 km), comparatively large topside plasma densities (above 20 000/cc), and low energies (10 eV). Upflowing ions with bulk velocities up to 2 km/s are seen in conjunction with the poleward edge of a nightside substorm arc. The upflow is limited within the poleward edge to a region (a) of northward convection, (b) where Alfvénic and Pedersen...

  17. Regression of altitude-produced cardiac hypertrophy.

    Science.gov (United States)

    Sizemore, D. A.; Mcintyre, T. W.; Van Liere, E. J.; Wilson , M. F.

    1973-01-01

    The rate of regression of cardiac hypertrophy with time has been determined in adult male albino rats. The hypertrophy was induced by intermittent exposure to simulated high altitude. The percentage hypertrophy was much greater (46%) in the right ventricle than in the left (16%). The regression could be adequately fitted to a single exponential function with a half-time of 6.73 plus or minus 0.71 days (90% CI). There was no significant difference in the rates of regression for the two ventricles.

  18. Ascent schedules, acute altitude illness, and altitude acclimatization: Observations on the Yushu Earthquake

    Institute of Scientific and Technical Information of China (English)

    Wu Tianyi; Hou Shike; Li Shuzhi; Li Wenxiang; Gen Deng

    2013-01-01

    During the Yushu Earthquake on April 14,2010,a large number of rescuers from sea level or lowlands ascended to the quake areas very rapidly or rapidly less than 24 h.However,Yushu Earthquake is the highest quake in the world at altitudes between 3750 m and 4878 m where is a serious hypoxic environment.A high incidence of acute altitude illness was found in the unacclimatized rescuers; the mountain rescue operation changed as "rescue the rescuers".Lesson from the Yushu Earthquake is that the occurrence of acute altitude illness may be closely related to the ascent schedules.This prompted us to study the relationship between ascent rate and the incidence and severity of acute altitude illness; five different groups were compared.The first group was 42 sea level male young soldiers who ascended to quake area very rapidly within 8 h at 4000 m; the second group was 48 sea level male young soldiers who ascended to 4000 m rapidly less than 18 h; the third group was 66 acclimatized medical workers from 2261 m who ascended to 4000 m rapidly within 12 h; the fourth group was 56 Tibetan medical workers from 2800 m who ascended to 4000 m rapidly within 8 h; the fifth group was 50 male sea level workers who ascended to 4000 m gradually over a period of 4 d.The results showed that the sea level rescuers ascended to 4000 m very rapidly or rapidly had the highest incidence of acute mountain sickness (AMS) with the greatest AMS scores and the lowest arterial oxygen saturation (SaO2) ; the sea level workers ascended to 4000 m gradually had moderate incidence of AMS with moderate AMS scores and SaO2 values; whereas the acclimatized and adapted rescuers had the lowest incidence of AMS,lowest AMS scores and higher SaO2; especially none AMS occurred in Tibetan rescuers.AMS score is inversely related to the ascent rate (r=-0.24,p<0.001).Additionally,acute altitude illness is significantly influenced by altitude acclimatization.The ascent rate is inversely related to

  19. [Hormonal variation during physical exertion at high altitude].

    Science.gov (United States)

    Sutton, J; Garmendia, F

    1977-01-01

    The influence of the physical exercise at high altitude on the endocrine function was studied in 8 normal native men of sea level and in 8 natives men of high altitude. The sea level dwellers were studied both, at sea level, during an acute exposure to low barometric pressure and after 3 months of acclimatization to altitudes over 3,500 meters above the sea level. The experiments at high altitude were conducted at an altitude of 4,500 meters above the sea level. Two types of exercise were carried out, sub-maximal and maximal, at fasting state, between 8 and 10 a.m. During an acute exposure to altitude the physical exercise produced a marked rise of glucose, cortisol and growth hormone and a fall in the insulin content of plasma. In the sea level dwellers, acclimatized to altitude during 3 months, an elevation of growth hormone was observed only during maximal physical effort. Marked variation in glucose and cortisol were observed during both types of exercise. This shows that in these subjects some adaptative changes have ocurred but of lesser extent as those observed in altitude natives. In the high altitude native higher basal concentrations of growth hormone and glucagón as well as a lower glucose concentration in blood, were found. During exercise the high altitude dweller showed no significant changes in somatotropin, meanwhile an important elevation of cortisol occurred. These findings indicate that the high altitude native has metabolic and endocrine responses to exercise similar to those found in well fitted atletes of sea level. The exposure to altitude provoked a rise in glucagon concentration directly proportional to the time of exposition ot altitude. The physical exercise did not elucidate any change in the glucagon content of blood. PMID:753199

  20. THE HIGH ALTITUDE GAMMA RAY OBSERVATORY, HAWC

    Directory of Open Access Journals (Sweden)

    M. M. González

    2011-01-01

    Full Text Available El volcán Sierra Negra en Puebla, México fue seleccionado para albergar a HAWC (High Altitude Water Cherenkov, un observatorio de gran apertura (2Pi sr, único en el mundo, capaz de observar contínuamente el cielo a energías de 0.1 a 100 TeV. HAWC consiste en un arreglo a una altitud de 4100 m sobre el nivel del mar de 300 contenedores de 7.3 m de diámetro y 5 m de altura llenos de agua pura y sensores de luz que observan partículas sumamente energ´eticas provenientes de los eventos más violentos del universo y será 15 veces más sensible que su antecesor Milagro. Las aportaciones científicas de Milagro han demostrado las capacidades únicas de este tipo de observatorios. En este trabajo se presentará HAWC y se discutirá brevemente su caso científico y capacidades.

  1. Development of the High Altitude Student Platform

    Science.gov (United States)

    Guzik, T. G.; Besse, S.; Calongne, A.; Dominique, A.; Ellison, S. B.; Gould, R.; Granger, D.; Olano, D.; Smith, D.; Stewart, M.; Wefel, J. P.

    2008-11-01

    The High Altitude Student Platform (HASP) was originally conceived to provide student groups with access to the near-space environment for flight durations and experiment capabilities intermediate between what is possible with small sounding balloons and low Earth orbit rocket launches. HASP is designed to carry up to twelve student payloads to an altitude of about 36 km with flight durations of 15 20 h using a small zero-pressure polyethylene film balloon. This provides a flight capability that can be used to flight-test compact satellites, prototypes and other small payloads designed and built by students. HASP includes a standard mechanical, power and communication interface for the student payload to simplify integration and allows the payloads to be fully exercised. Over the last two years a partnership between the NASA Balloon Program Office (BPO), Columbia Scientific Balloon Facility (CSBF), Louisiana State University (LSU), the Louisiana Board of Regents (BoR), and the Louisiana Space Consortium (LaSPACE) has led to the development, construction and, finally, the first flight of HASP with a complement of eight student payloads on September 4, 2006. Here we discuss the primary as-built HASP systems and features, the student payload interface, HASP performance during the first flight and plans for continuing HASP flights. The HASP project maintains a website at http://laspace.lsu.edu/hasp/ where flight application, interface documentation and status information can be obtained.

  2. Work at high altitude and oxidative stress: antioxidant nutrients.

    Science.gov (United States)

    Askew, E W

    2002-11-15

    A significant portion of the world's geography lies above 10,000 feet elevation, an arbitrary designation that separates moderate and high altitude. Although the number of indigenous people living at these elevations is relatively small, many people travel to high altitude for work or recreation, exposing themselves to chronic or intermittent hypoxia and the associated risk of acute mountain sickness (AMS) and less frequently, high altitude pulmonary edema (HAPE) and high altitude cerebral edema (HACE). The symptoms of AMS (headache, nausea, anorexia, fatigue, lassitude) occur in those who travel too high, too fast. Some investigators have linked the development of these symptoms with the condition of altered blood-brain barrier permeability, possibly related to hypoxia induced free radical formation. The burden of oxidative stress increases during the time spent at altitude and may even persist for some time upon return to sea level. The physiological and medical consequences of increased oxidative stress engendered by altitude is unclear; indeed, hypoxia is believed to be the trigger for the cascade of signaling events that ultimately leads to adaptation to altitude. These signaling events include the generation of reactive oxygen species (ROS) that may elicit important adaptive responses. If produced in excess, however, these ROS may contribute to impaired muscle function and reduced capillary perfusion at altitude or may even play a role in precipitating more serious neurological and pulmonary crisis. Oxidative stress can be observed at altitude without strenuous physical exertion; however, environmental factors other than hypoxia, such as exercise, UV light exposure and cold exposure, can also contribute to the burden. Providing antioxidant nutrients via the diet or supplements to the diet can reduce oxidative stress secondary to altitude exposure. In summary, the significant unanswered question concerning altitude exposure and antioxidant supplementation is

  3. The physiology and biomechanics of avian flight at high altitude

    OpenAIRE

    Altshuler, Douglas L.; Dudley, Robert

    2006-01-01

    Many birds fly at high altitude, either during long-distance flights or by virtue of residence in high-elevation habitats. Among the many environmental features that vary systematically with altitude, five have significant consequences for avian flight performance: ambient wind speeds, air temperature, humidity, oxygen availability, and air density. During migratory flights, birds select flight altitudes that minimize energy expenditure via selection of advantageous tail- and cross-winds. Oxy...

  4. Common High Altitudes Illnesses a Primer for Healthcare Provider

    OpenAIRE

    Mohsenin, Vahid

    2015-01-01

    Exposure to high altitude imposes significant strain on cardiopulmonary system and the brain. As a consequence, sojourners to high altitude frequently experience sleep disturbances, often reporting restless and sleepless nights. At altitudes above 3,000 meters (9,800 ft) almost all healthy subjects develop periodic breathing especially during NREM sleep. Sleep architecture gradually improves with increased NREM and REM sleep despite persistence of periodic breathing. The primary reason for pe...

  5. Plasticity of the muscle proteome to exercise at altitude

    OpenAIRE

    Flueck, Martin

    2009-01-01

    The ascent of humans to the summits of the highest peaks on Earth initiated a spurt of explorations into the physiological consequences of physical activity at altitude. The past three decades have demonstrated that the resetting of respiratory and cardiovascular control with chronic exposure to altitudes above 4000 m is accompanied by important structural-functional adjustments of skeletal muscle. The fully altitude-adapted phenotype preserves energy charge at reduced aerobic capacity throug...

  6. Neurophysiological Problems in Snow Bound High Altitude Areas

    Directory of Open Access Journals (Sweden)

    W. Selvamurthy

    1984-10-01

    Full Text Available A series of studies have been conducted to evaluate the neurophysiological responses in young healthy soldiers during acclimatization at 3,500m altitude in Western Himalayas. The responses of autonomic nervous system, electroencephalogram hypothalamic thermoregulatory efficiency, orthostatic tolerance, sleep profile and effects of sleep deprivation have been studied in fresh inductees during three to five weeks of acclimatization at high altitude and compared with those of one year acclimatized lowlanders and high altitude natives. Physiological significance of these neurophysiological responses in the process of altitude adaptation is discussed in the light of current knowledge in the field.

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

    DEFF Research Database (Denmark)

    Qiu, Qiang; Zhang, Guojie; Ma, Tao;

    2012-01-01

    Domestic yaks (Bos grunniens) provide meat and other necessities for Tibetans living at high altitude on the Qinghai-Tibetan Plateau and in adjacent regions. Comparison between yak and the closely related low-altitude cattle (Bos taurus) is informative in studying animal adaptation to high altitude...... of protein domains involved in sensing the extracellular environment and hypoxic stress. Positively selected and rapidly evolving genes in the yak lineage are also found to be significantly enriched in functional categories and pathways related to hypoxia and nutrition metabolism. These findings may have...... important implications for understanding adaptation to high altitude in other animal species and for hypoxia-related diseases in humans....

  8. Aviation fuel property effects on altitude relight

    Science.gov (United States)

    Venkataramani, K.

    1987-01-01

    The major objective of this experimental program was to investigate the effects of fuel property variation on altitude relight characteristics. Four fuels with widely varying volatility properties (JP-4, Jet A, a blend of Jet A and 2040 Solvent, and Diesel 2) were tested in a five-swirl-cup-sector combustor at inlet temperatures and flows representative of windmilling conditions of turbofan engines. The effects of fuel physical properties on atomization were eliminated by using four sets of pressure-atomizing nozzles designed to give the same spray Sauter mean diameter (50 + or - 10 micron) for each fuel at the same design fuel flow. A second series of tests was run with a set of air-blast nozzles. With comparable atomization levels, fuel volatility assumes only a secondary role for first-swirl-cup lightoff and complete blowout. Full propagation first-cup blowout were independent of fuel volatility and depended only on the combustor operating conditions.

  9. Cardiovascular Response to High Altitude Hypoxia

    Directory of Open Access Journals (Sweden)

    S. C. Manchanda

    1984-10-01

    Full Text Available Normal and abnormal cardiovascular response to high altitude (HA hypoxia were studied in 98 healthy subjects and in 15 patients with HA pulmonary oedema (HAPO and acute mountain sickness (AMS at an altitudeof 3,658 m. The healthy sea level (SL residents showed marked blood volume changes during the first week with pulmonary hypotension and depression of left ventricular (LV performance and physical work capacity (PWC. The HA natives, however, had better LV performance and PWC indicating a better adaptation to HA hypoxia. HAPO subjects showed evidence of severe pulmonary hypertension with normal left atrial pressures but the exact mechanism of this condition is still not clear. AMS subjects showed no circulatory abnormalities 'but had relative hypercapnia and severe hypoxemia suggesting that AMS may be causcd by relative hyposensitiveness of the respiratory centre to hypoxia or hypercapnia.

  10. Sleep apneas and high altitude newcomers.

    Science.gov (United States)

    Goldenberg, F; Richalet, J P; Onnen, I; Antezana, A M

    1992-10-01

    Sleep and respiration data from two French medical high altitude expeditions (Annapurna 4,800 m and Mt Sajama 6,542 m) are presented. Difficulties in maintaining sleep and a SWS decrease were found with periodic breathing (PB) during both non-REM and REM sleep. Extent of PB varied considerably among subjects and was not correlated to the number of arousals but to the intercurrent wakefulness duration. There was a positive correlation between the time spent in PB and the individual hypoxic ventilatory drive. The relation between PB, nocturnal desaturation, and mountain sickness intensity are discussed. Acclimatization decreased the latency toward PB and improved sleep. Hypnotic benzodiazepine intake (loprazolam 1 mg) did not worsen either SWS depression or apneas and allowed normal sleep reappearance after acclimatization.

  11. Mechanisms of Altitude-Related Cough/Mécanismes de la Toux Liée à l’Altitude

    OpenAIRE

    Mason, Nicholas

    2012-01-01

    The original work presented in this thesis investigates some of the mechanisms that may be responsible for the aetiology of altitude-related cough. Particular attention is paid to its relationship to the long recognised, but poorly understood, changes in lung volumes that occur on ascent to altitude. The literature relevant to this thesis is reviewed in Chapter 1. Widespread reports have long existed of a debilitating cough affecting visitors to high altitude that can incapacitate the suff...

  12. 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

  13. 14 CFR 91.177 - Minimum altitudes for IFR operations.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Minimum altitudes for IFR operations. 91.177 Section 91.177 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Instrument Flight Rules § 91.177 Minimum altitudes for IFR operations. (a) Operation of aircraft at...

  14. 14 CFR 93.307 - Minimum flight altitudes.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Minimum flight altitudes. 93.307 Section 93...) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Special Flight Rules in the Vicinity of Grand Canyon National Park, AZ § 93.307 Minimum flight altitudes. Except in an emergency, or...

  15. 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.

  16. 14 CFR 121.661 - Initial approach altitude: Flag operations.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Initial approach altitude: Flag operations... OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS Dispatching and Flight Release Rules § 121.661 Initial approach altitude: Flag operations. When making an initial approach to a...

  17. Increased resting bronchial tone in normal subjects acclimatised to altitude

    OpenAIRE

    Wilson, C.; Bakewell, S; M. Miller; Hart, N; McMorrow, R; BARRY, P.; Collier, D; Watt, S; Pollard, A.

    2002-01-01

    Background: Normal subjects frequently experience troublesome respiratory symptoms when acclimatised to altitude. Bronchial hyperresponsiveness (BHR) and full and partial flow-volume loops were measured before and after ascent to 5000 m altitude to determine if there are changes in resting bronchial tone and BHR that might explain the symptoms.

  18. Microgravity combustion experiment using high altitude balloon.

    Science.gov (United States)

    Kan, Yuji

    In JAXA, microgravity experiment system using a high altitude balloon was developed , for good microgravity environment and short turn-around time. In this publication, I give an account of themicrogravity experiment system and a combustion experiment to utilize the system. The balloon operated vehicle (BOV) as a microgravity experiment system was developed from 2004 to 2009. Features of the BOV are (1) BOV has double capsule structure. Outside-capsule and inside-capsule are kept the non-contact state by 3-axis drag-free control. (2) The payload is spherical shape and itsdiameter is about 300 mm. (3) Keep 10-4 G level microgravity environment for about 30 seconds However, BOV’s payload was small, and could not mount large experiment module. In this study, inherits the results of past, we established a new experimental system called “iBOV” in order toaccommodate larger payload. Features of the iBOV are (1) Drag-free control use for only vertical direction. (2) The payload is a cylindrical shape and its size is about 300 mm in diameter and 700 mm in height. (3) Keep 10-3-10-4 G level microgravity environment for about 30 seconds We have "Observation experiment of flame propagation behavior of the droplets column" as experiment using iBOV. This experiment is a theme that was selected first for technical demonstration of iBOV. We are conducting the flame propagation mechanism elucidation study of fuel droplets array was placed at regular intervals. We conducted a microgravity experiments using TEXUS rocket ESA and drop tower. For this microgravity combustion experiment using high altitude balloon, we use the Engineering Model (EM) for TEXUS rocket experiment. The EM (This payload) consists of combustion vessel, droplets supporter, droplets generator, fuel syringe, igniter, digital camera, high-speed camera. And, This payload was improved from the EM as follows. (1) Add a control unit. (2) Add inside batteries for control unit and heater of combustion

  19. General introduction to altitude adaptation and mountain sickness

    DEFF Research Database (Denmark)

    Bartsch, P.; Saltin, B.

    2008-01-01

    over 24-48 h to improve the oxygen-carrying capacity of the blood, and is further improved during a prolonged sojourn at altitude through an enhanced erythropoiesis and larger Hb mass, allowing for a partial or full restoration of the blood volume and arterial oxygen content. Most of these adaptations...... are observed from quite low altitudes [approximately 1000 m above sea level (m a.s.l.)] and become prominent from 2000 m a.s.l. At these higher altitudes additional adaptations occur, one being a reduction in the maximal heart rate response and consequently a lower peak cardiac output. Thus, in spite....... The alteration at the muscle level at altitude is minor and so is the effect on the metabolism, although it is debated whether a possible reduction in blood lactate accumulation occurs during exercise at altitude. Transient acute mountain sickness (headache, anorexia, and nausea) is present in 10-30% of subjects...

  20. Low altitude dose measurements from APEX, CRRES and DMSP.

    Science.gov (United States)

    Mullen, E G; Gussenhoven, M S; Bell, J T; Madden, D; Holeman, E; Delorey, D

    1998-01-01

    Dosimeter data taken on the APEX (1994-1996), CRRES (1990-1991) and DMSP (1984-1987) satellites have been used to study the low altitude (down to 350 km) radiation environment. Of special concern has been the inner edge of the inner radiation belt due to its steep gradient. We have constructed dose models of the inner edge of the belt from all three spacecraft and put them into a personal computer utility, called APEXRAD, that calculates dose for user-selected orbits. The variation of dose for low altitude, circular orbits is given as a function of altitude, inclination and particle type. Dose-depth curves show that shielding greater than approximately 1/4 in Al is largely ineffectual for low altitude orbits. The contribution of outer zone electrons to low altitude dose is shown to be important only for thin shields and to have significant variation with magnetic activity and solar cycle.

  1. Impact of Altitude on Power Output during Cycling Stage Racing.

    Directory of Open Access Journals (Sweden)

    Laura A Garvican-Lewis

    Full Text Available The purpose of this study was to quantify the effects of moderate-high altitude on power output, cadence, speed and heart rate during a multi-day cycling tour.Power output, heart rate, speed and cadence were collected from elite male road cyclists during maximal efforts of 5, 15, 30, 60, 240 and 600 s. The efforts were completed in a laboratory power-profile assessment, and spontaneously during a cycling race simulation near sea-level and an international cycling race at moderate-high altitude. Matched data from the laboratory power-profile and the highest maximal mean power output (MMP and corresponding speed and heart rate recorded during the cycling race simulation and cycling race at moderate-high altitude were compared using paired t-tests. Additionally, all MMP and corresponding speeds and heart rates were binned per 1000 m (3000 m according to the average altitude of each ride. Mixed linear modelling was used to compare cycling performance data from each altitude bin.Power output was similar between the laboratory power-profile and the race simulation, however MMPs for 5-600 s and 15, 60, 240 and 600 s were lower (p ≤ 0.005 during the race at altitude compared with the laboratory power-profile and race simulation, respectively. Furthermore, peak power output and all MMPs were lower (≥ 11.7%, p ≤ 0.001 while racing >3000 m compared with rides completed near sea-level. However, speed associated with MMP 60 and 240 s was greater (p < 0.001 during racing at moderate-high altitude compared with the race simulation near sea-level.A reduction in oxygen availability as altitude increases leads to attenuation of cycling power output during competition. Decrement in cycling power output at altitude does not seem to affect speed which tended to be greater at higher altitudes.

  2. Increased oxidative stress following acute and chronic high altitude exposure.

    Science.gov (United States)

    Jefferson, J Ashley; Simoni, Jan; Escudero, Elizabeth; Hurtado, Maria-Elena; Swenson, Erik R; Wesson, Donald E; Schreiner, George F; Schoene, Robert B; Johnson, Richard J; Hurtado, Abdias

    2004-01-01

    The generation of reactive oxygen species is typically associated with hyperoxia and ischemia reperfusion. Recent evidence has suggested that increased oxidative stress may occur with hypoxia. We hypothesized that oxidative stress would be increased in subjects exposed to high altitude hypoxia. We studied 28 control subjects living in Lima, Peru (sea level), at baseline and following 48 h exposure to high altitude (4300 m). To assess the effects of chronic altitude exposure, we studied 25 adult males resident in Cerro de Pasco, Peru (altitude 4300 m). We also studied 27 subjects living in Cerro de Pasco who develop excessive erythrocytosis (hematocrit > 65%) and chronic mountain sickness. Acute high altitude exposure led to increased urinary F(2)-isoprostane, 8-iso PGF(2 alpha) (1.31 +/- 0.8 microg/g creatinine versus 2.15 +/- 1.1, p = 0.001) and plasma total glutathione (1.29 +/- 0.10 micromol versus 1.37 +/- 0.09, p = 0.002), with a trend to increased plasma thiobarbituric acid reactive substance (TBARS) (59.7 +/- 36 pmol/mg protein versus 63.8 +/- 27, p = NS). High altitude residents had significantly elevated levels of urinary 8-iso PGF(2 alpha) (1.3 +/- 0.8 microg/g creatinine versus 4.1 +/- 3.4, p = 0.007), plasma TBARS (59.7 +/- 36 pmol/mg protein versus 85 +/- 28, p = 0.008), and plasma total glutathione (1.29 +/- 0.10 micromol versus 1.55 +/- 0.19, p < 0.0001) compared to sea level. High altitude residents with excessive erythrocytosis had higher levels of oxidative stress compared to high altitude residents with normal hematological adaptation. In conclusion, oxidative stress is increased following both acute exposure to high altitude without exercise and with chronic residence at high altitude.

  3. Accuracy of handheld blood glucose meters at high altitude.

    Directory of Open Access Journals (Sweden)

    Pieter de Mol

    Full Text Available 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 studies reported bias in blood glucose measurements using different BGMs at high altitude. We hypothesized that glucose-oxidase based BGMs are more influenced by the lower atmospheric oxygen pressure at altitude than glucose dehydrogenase based BGMs. METHODOLOGY/PRINCIPAL FINDINGS: Glucose measurements at simulated altitude of nine BGMs (six glucose dehydrogenase and three glucose oxidase BGMs were compared to glucose measurement on a similar BGM at sea level and to a laboratory glucose reference method. Venous blood samples of four different glucose levels were used. Moreover, two glucose oxidase and two glucose dehydrogenase based BGMs were evaluated at different altitudes on Mount Kilimanjaro. Accuracy criteria were set at a bias 6.5 mmol/L and <1 mmol/L from reference glucose (when <6.5 mmol/L. No significant difference was observed between measurements at simulated altitude and sea level for either glucose oxidase based BGMs or glucose dehydrogenase based BGMs as a group phenomenon. Two GDH based BGMs did not meet set performance criteria. Most BGMs are generally overestimating true glucose concentration at high altitude. CONCLUSION: At simulated high altitude all tested BGMs, including glucose oxidase based BGMs, did not show influence of low atmospheric oxygen pressure. All BGMs, except for two GDH based BGMs, performed within predefined criteria. At true high altitude one GDH based BGM had best precision and accuracy.

  4. The high-altitude water Cherenkov Observatory

    Energy Technology Data Exchange (ETDEWEB)

    Mostafa, Miguel A., E-mail: miguel@psu.edu [Department of Physics, Colorado State University, Ft Collins, CO (United States)

    2014-07-01

    The High-Altitude Water Cherenkov (HAWC) observatory is a large field of view, continuously operated, TeV γ -ray experiment under construction at 4,100ma.s.l. in Mexico. The HAWC observatory will have an order of magnitude better sensitivity, angular resolution, and background rejection than its predecessor, the Milagro experiment. The improved performance will allow to detect both the transient and steady emissions, to study the Galactic diffuse emission at TeV energies, and to measure or constrain the TeV spectra of GeV γ -ray sources. In addition, HAWC will be the only ground-based instrument capable of detecting prompt emission from γ -ray bursts above 50 GeV. The HAWC observatory will consist of an array of 300 water Cherenkov detectors (WCDs), each with four photomultiplier tubes. This array is currently under construction on the flanks of the Sierra Negra volcano near the city of Puebla, Mexico. The first 30 WCDs (forming an array approximately the size of Milagro) were deployed in Summer 2012, and 100 WCDs will be taking data by May, 2013. We present in this paper the motivation for constructing the HAWC observatory, the status of the deployment, and the first results from the constantly growing array. (author)

  5. Solar electric energy supply at high altitude

    Energy Technology Data Exchange (ETDEWEB)

    Knaupp, W.; Mundschau, E. [Zentrum fur Sonnenenergie- und Wasserstoff-Forschung (ZSW), Ulm (Germany)

    2004-04-01

    Solar-hydrogen systems were analyzed regarding their usability as energy supply system for high altitude platforms. In a first step for an assessment of solar and photovoltaic resources near-ground spectral transmittances of atmosphere were extended with simplified height correction functions to achieve spectral irradiance descriptions versus atmospheric height up to 25 km. The influence of atmospheric height to different solar cell technologies regarding electrical performance was quantified at some examples for the aspect of spectral distribution with the help of the introduced spectral height factor. The main attention during analysis of the whole solar-hydrogen energy system was directed to characteristics of current or near term available technology. Specific power weight of photovoltaic system, electrolyzer, fuel cell and gas tanks and their dependence on operation mode and power range were assessed. A pre-design of a solar-hydrogen energy system was carried out for an airship (volume 580,000 m3) withstanding continuous wind speeds up to {approx} 130 km/h. The calculated coverage ratio of photovoltaic and load share of energy system mark the frame of usability. Depending on the airship size, shape and other external boundary conditions the total electrical energy demand could be covered by a solar-hydrogen energy system of current or near term technology for full year operation. However further investigations are necessary regarding e.g. further mass reductions. (author)

  6. The High Altitude Water Cherenkov Observatory

    CERN Document Server

    ,

    2013-01-01

    The High Altitude Water Cherenkov (HAWC) observatory is a large field of view, continuously operated, TeV gamma-ray experiment under construction at 4,100 m a.s.l. in Mexico. The HAWC observatory will have an order of magnitude better sensitivity, angular resolution, and background rejection than its predecessor, the Milagro experiment. The improved performance will allow us to detect both transient and steady emissions, to study the Galactic diffuse emission at TeV energies, and to measure or constrain the TeV spectra of GeV gamma-ray sources. In addition, HAWC will be the only ground-based instrument capable of detecting prompt emission from gamma-ray bursts above 50 GeV. The HAWC observatory will consist of an array of 300 water Cherenkov detectors (WCDs), each with four photomultiplier tubes. This array is currently under construction on the flanks of the Sierra Negra volcano near the city of Puebla, Mexico. The first thirty WCDs (forming an array approximately the size of Milagro) were deployed in Summer...

  7. Effects of high altitude and exercise on marksmanship.

    Science.gov (United States)

    Tharion, W J; Hoyt, R W; Marlowe, B E; Cymerman, A

    1992-02-01

    The effects of exercise and high altitude (3,700 m to 4,300 m) on marksmanship accuracy and sighting time were quantified in 16 experienced marksmen. Subjects dry-fired a disabled rifle equipped with a laser-based system from a free-standing position. The 2.3-cm circular target was at a distance of 5 m. Marksmanship was assessed under the following conditions: 1) at rest at sea level; 2) immediately after a 21-km run/walk ascent from 1,800 m to 4,300 m elevation; 3) at rest during days 1 to 3 at altitude; 4) at rest during days 14 to 16 at altitude; and 5) immediately after a second ascent after 17 d at altitude. Exercise reduced marksmanship accuracy (p less than 0.05) but did not affect sighting time. Acute altitude exposure reduced marksmanship accuracy, and decreased sighting time (p less than 0.05). However, after residence at altitude, accuracy and sighting time at rest returned to sea level values. Exercise and acute altitude exposure had similar but independent detrimental effects on marksmanship. PMID:1546938

  8. 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.

  9. Mitochondrial DNA response to high altitude: a new perspective on high-altitude adaptation.

    Science.gov (United States)

    Luo, Yongjun; Yang, Xiaohong; Gao, Yuqi

    2013-08-01

    Mitochondria are the energy metabolism centers of the cell. More than 95% of cellular energy is produced by mitochondrial oxidative phosphorylation. Hypoxia affects a wide range of energy generation and consumption processes in animals. The most important mechanisms limiting ATP consumption increase the efficiency of ATP production and accommodate the reduced production of ATP by the body. All of these mechanisms relate to changes in mitochondrial function. Mitochondrial function can be affected by variations in mitochondrial DNA, including polymorphisms, content changes, and deletions. These variations play an important role in acclimatization or adaptation to hypoxia. In this paper, the association between mitochondrial genome sequences and high-altitude adaptation is reviewed.

  10. Can patients with coronary heart disease go to high altitude?

    Science.gov (United States)

    Dehnert, Christoph; Bärtsch, Peter

    2010-01-01

    Tourism to high altitude is very popular and includes elderly people with both manifest and subclinical coronary heart disease (CHD). Thus, risk assessment regarding high altitude exposure of patients with CHD is of increasing interest, and individual recommendations are expected despite the lack of sufficient scientific evidence. The major factor increasing cardiac stress is hypoxia. At rest and for a given external workload, myocardial oxygen demand is increased at altitude, particularly in nonacclimatized individuals, and there is some evidence that blood-flow reserve is reduced in atherosclerotic coronary arteries even in the absence of severe stenosis. Despite a possible imbalance between oxygen demand and oxygen delivery, studies on selected patients have shown that exposure and exercise at altitudes of 3000 to 3500 m is generally safe for patients with stable CHD and sufficient work capacity. During the first days at altitude, patients with stable angina may develop symptoms of myocardial ischemia at slightly lower heart rate x  blood-pressure products. Adverse cardiac events, however, such as unstable angina coronary syndromes, do not occur more frequently compared with sea level except for those who are unaccustomed to exercise. Therefore, training should start before going to altitude, and the altitude-related decrease in exercise capacity should be considered. Travel to 3500 m should be avoided unless patients have stable disease, preserved left ventricular function without residual capacity, and above-normal exercise capacity. CHD patients should avoid travel to elevations above 4500 m owing to severe hypoxia at these altitudes. The risk assessment of CHD patients at altitude should always consider a possible absence of medical support and that cardiovascular events may turn into disaster. PMID:20919884

  11. Oxidative stress and the high altitude environment

    Directory of Open Access Journals (Sweden)

    Jakub Krzeszowiak

    2013-03-01

    Full Text Available In the recent years there has been considerable interest in mountain sports, including mountaineering, owing to the general availability of climbing clothing and equipment as well trainings and professional literature. This raised a new question for the environmental and mountain medicine: Is mountaineering harmful to health? Potential hazards include the conditions existing in the alpine environment, i.e. lower atmospheric pressure leading to the development of hypobaric hypoxia, extreme physical effort, increased UV radiation, lack of access to fresh food, and mental stress. A reasonable measure of harmfulness of these factors is to determine the increase in the level of oxidative stress. Alpine environment can stimulate the antioxidant enzyme system but under specific circumstances it may exceed its capabilities with simultaneous consumption of low-molecular antioxidants resulting in increased generation of reactive oxygen species (ROS. This situation is referred to as oxidative stress. Rapid and uncontrolled proliferation of reactive oxygen species leads to a number of adverse changes, resulting in the above-average damage to the lipid structures of cell membranes (peroxidation, proteins (denaturation, and nucleic acids. Such situation within the human body cannot take place without resultant systemic consequences. This explains the malaise of people returning from high altitude and a marked decrease in their physical fitness. In addition, a theory is put forward that the increase in the level of oxidative stress is one of the factors responsible for the onset of acute mountain sickness (AMS. However, such statement requires further investigation because the currently available literature is inconclusive. This article presents the causes and effects of development of oxidative stress in the high mountains.

  12. Cognitive performance in high altitude Andean residents compared to low altitude populations: from childhood to older age

    OpenAIRE

    Hill, Catherine M.; Dimitriou, Dagmara; Baya, Ana; Webster, Rebecca; Gavlak-Dingle, Johanna; Lesperance, Veline; Healthcote, Kate; Romola S Bucks

    2014-01-01

    Objectives: To assess cognition in populations born and living at high (3700m) and low altitude (500m) in Bolivia, who were similar for both socio-economic status and genetic ancestry. To determine whether high altitude hypoxia influences cognitive decline across the life-span. Method: In total, 191 healthy participants aged 4 to 85 years were assessed at high (N = 94; 33; 35% male) and low altitude (N = 97; 46, 47% male) on a battery of cognitive tasks: fluid intelligence, attention, s...

  13. Biochemical Aspects of Acclimatization of Man to High Altitude Stress

    Directory of Open Access Journals (Sweden)

    K. K. Srivastava

    1975-07-01

    Full Text Available The paper reviews the biochemical aspects of acclimatization of human body to high altitude with particular reference to the adaptive changes in Skeletal muscles, hepatic function, adrenal function and carbohydrate metabolism.

  14. Altitude Compensating Nozzle Transonic Performance Flight Demonstration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Altitude compensating nozzles continue to be of interest for use on future launch vehicle boosters and upper stages because of their higher mission average Isp and...

  15. NHAP = National High-Altitude Aerial Photography: 1980 - 1989

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The National High Altitude Photography (NHAP) program, which was operated from 1980-1989, was coordinated by the U.S. Geological Survey as an interagency project to...

  16. Investigation of Correction Method of the Spacecraft Low Altitude Ranging

    CERN Document Server

    Liu, Jing-Lei; Wu, Shi-Tong; Huang, Wei

    2015-01-01

    gamma ray altitude control system is an important equipment for deep space exploration and sample return mission, its main purpose is a low altitude measurement of the spacecraft based on Compton Effect at the moment when it lands on extraterrestrial celestial or sampling returns to the Earth land, and an ignition altitude correction of the spacecraft retrograde landing rocket at different landing speeds. This paper presents an ignition altitude correction method of the spacecraft at different landing speeds, based on the number of particles gamma ray reflected field gradient graded. Through the establishment of a theoretical model, its algorithm feasibility is proved by a mathematical derivation and verified by an experiment, and also the adaptability of the algorithm under different parameters is described. The method provides a certain value for landing control of the deep space exploration spacecraft landing the planet surface.

  17. Collision probability at low altitudes resulting from elliptical orbits

    Science.gov (United States)

    Kessler, Donald J.

    1990-01-01

    The probability of collision between a spacecraft and another object is calculated for various altitude and orbit conditions, and factors affecting the probability are discussed. It is shown that a collision can only occur when the spacecraft is located at an altitude which is between the perigee and apogee altitudes of the object and that the probability per unit time is largest when the orbit of the object is nearly circular. However, at low altitudes, the atmospheric drag causes changes with time of the perigee and the apogee, such that circular orbits have a much shorter lifetime than many of the elliptical orbits. Thus, when the collision probability is integrated over the lifetime of the orbiting object, some elliptical orbits are found to have much higher total collision probability than circular orbits. Rocket bodies used to boost payloads from low earth orbit to geosynchronous orbit are an example of objects in these elliptical orbits.

  18. Soldier at High Altitude: Problem & Preventive Measures

    Directory of Open Access Journals (Sweden)

    S.S Purkayastha

    2000-04-01

    Full Text Available Due to military and j trategic reasons, a large body of troops is being regularly dcployed in the snowbound areas through ut the Himalayan regions to guard Ihe Ironliers. Thc mountain environment at high 'allitude (HA consisls of several faclors alien lo plain dwellers, which evoke a series of physiological responses in human system. Some of the sea' level residents on induction to HA suffer from several unloward symploms of HA" ailmenls varying from mild-lo-severe degrees. Suddenexposure to HA is detrimental to physical and mental  performance of the low landers and  certain cases, may even lead to dreaded condition like high altitude pulmonary oedema (HAPO. These may make a man Jisturbed physically and mentally. So, there is a need lo prevent such hazards v(hich ispossible if the individual is aware of the problems and prevenlive measures ofHA ailments in advance, before going to HA for a safe and happy living there. Hence, a noble effort has been made to provide guidelines to create awareness about physical and physiological problems of life at HA and themethods of protection against its ill-effects for the soldiers, mountaineers and sojourners conducting scientific trials it HA. In th.:s revieJ, an attempt has been made to describe vital aspects of HA in a popular way, st~ing with its concept and various environmental factors which exert considerableettects on human body functions, heallh and performance on exposure to such environment, on the b¥is of a series of studies coitlucted at Ithe Defence Institute of Physiology & Allied Sciences, Delhi, oVer the years. The most important featurelof HA (3,000 m and above is hypoxia or deficiency ofoxygej1 in the body. Olher cnvironmental tactors are: scverc cold, high velocity wind, low rclalivc humidily, high solar radiatior, increased ultraviolet radialion and difficult terrain. These faclors are responsible for various HA cWtdc old syndromes, viz., acute mountain sickness, HAPO, dehydration,4

  19. Pulmonary artery pressure limits exercise capacity at high altitude.

    OpenAIRE

    Naeije, Robert; Huez, Sandrine; Lamotte, Michel; Retailleau, Kathleen; Neupane, S; Abramowicz, Daniel; Faoro, Vitalie

    2010-01-01

    Altitude exposure is associated with decreased exercise capacity and increased pulmonary vascular resistance (PVR). Echocardiographic measurements of pulmonary haemodynamics and a cardiopulmonary exercise test were performed in 13 healthy subjects at sea level, in normoxia and during acute hypoxic breathing (1 h, 12% oxygen in nitrogen), and in 22 healthy subjects after acclimatisation to an altitude of 5,050 m. The measurements were obtained after randomisation, double-blinded to the intake ...

  20. Isothermal pumping analysis for high-altitude tethered balloons

    OpenAIRE

    Kuo, Kirsty A.; Hunt, Hugh E.M.

    2015-01-01

    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...

  1. 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.

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

    Institute of Scientific and Technical Information of China (English)

    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...

  3. Aging, Tolerance to High Altitude, and Cardiorespiratory Response to Hypoxia.

    Science.gov (United States)

    Richalet, Jean-Paul; Lhuissier, François J

    2015-06-01

    Richalet, Jean-Paul, and François J. Lhuissier. Aging, tolerance to high altitude, and cardiorespiratory response to hypoxia. High Alt Med Biol. 16:117-124, 2015.--It is generally accepted that aging is rather protective, at least at moderate altitude. Some anecdotal reports even mention successful ascent of peaks over 8000 m and even Everest by elderly people. However, very few studies have explored the influence of aging on tolerance to high altitude and prevalence of acute high altitude related diseases, taking into account all confounding factors such as speed of ascent, altitude reached, sex, training status, and chemo-responsiveness. Changes in physiological responses to hypoxia with aging were assessed through a cross-sectional 20-year study including 4675 subjects (2789 men, 1886 women; 14-85 yrs old) and a longitudinal study including 30 subjects explored at a mean 10.4-year interval. In men, ventilatory response to hypoxia increased, while desaturation was less pronounced with aging. Cardiac response to hypoxia was blunted with aging in both genders. Similar results were found in the longitudinal study, with a decrease in cardiac and an increase in ventilatory response to hypoxia with aging. These adaptive responses were less pronounced or absent in post-menopausal untrained women. In conclusion, in normal healthy and active subjects, aging has no deleterious effect on cardiac and ventilatory responses to hypoxia, at least up to the eighth decade. Aging is not a contraindication for high altitude, as far as no pathological condition interferes and physical fitness is compatible with the intensity of the expected physical demand of one's individual. Physiological evaluation through hypoxic exercise testing before going to high altitude is helpful to detect risk factors of severe high altitude-related diseases. PMID:25946570

  4. Evolutionary adaptation to high altitude: a view from in utero

    OpenAIRE

    Julian, Colleen Glyde; Wilson, Megan J.; Moore, Lorna G.

    2009-01-01

    A primary focus within biological anthropology has been to elucidate the processes of evolutionary adaptation. A. Roberto Frisancho helped move anthropology towards more mechanistic explanations of human adaptation by drawing attention to the importance of the functional relevance of human variation. Using the natural laboratory of high altitude, he and others asked whether the unique physiology of indigenous high-altitude residents was the result of acclimatization, developmental plasticity ...

  5. Birth weight and altitude: a study in Peruvian communities.

    Science.gov (United States)

    Mortola, J P; Frappell, P B; Aguero, L; Armstrong, K

    2000-03-01

    We tested the hypothesis that at high altitude birth weight decreases once a critical barometric pressure (Pb) is reached. Birth weight data covering the 1-year period from November 1997 to October 1998 were collected in Peru from the data files of 15 community and mining centers between sea level and 4575 m altitude. These centers are scattered along the main road that joins Lima (on the Pacific shore) to Cerro de Pasco (4330 m) and surroundings. Above approximately 2000 m (ie, at Pb below approximately 590 mm Hg, inspired O(2) partial pressure of approximately 114 mm Hg) and up to approximately 4500 m altitude birth weight declined at an average of 65 g for every additional 500 m altitude (or 105 g for every additional 50 mm Hg drop in Pb). This pattern did not differ between sexes. Averages and modal distributions of the birth weight from 2 hospitals in Cerro de Pasco (4330 m) serving different social groups were similar. Body length at birth was similar at various altitudes, with the exception of the 2 highest locations above 4500 m, where it was slightly reduced. From these data, together with additional data collected in the North of Peru (Chacas, 3360 m) and with results from other ethnic groups previously published, we conclude that the drop in birth weight at altitude is (1) apparent once the critical Pb of approximately 590 mm Hg is reached, corresponding to an altitude of approximately 2000 m, (2) proportional to the increase in altitude between approximately 2000 m and 4500 m, and (3) independent from socioeconomic factors.

  6. LOW ALTITUDE AIRSHIPS FOR SEAMLESS MOBILE COMMUNICATION IN AIR TRAVEL

    OpenAIRE

    Madhu D; Santhoshkumar M K; Swarnalatha Srinivas; Narendra Kumar G

    2014-01-01

    The Aviation Administration policy prohibits the use of mobile phones in Aircraft during transition for the reason it may harm their communication system due to Electromagnetic interference. In case the user wants to access cellular network at higher altitudes, base station access is a problem. Large number of channels are allocated to a single user moving at high speed by various Base Stations in the vicinity to service the request requiring more resources. Low Altitude Platfo...

  7. Prior altitude experience of climbers attempting to summit Aconcagua.

    Science.gov (United States)

    Borm, Nicholas; Van Roo, Jon D; Pesce, Carlos; Courtney, D Mark; Malik, Sanjeev; Lazio, Matthew P

    2011-01-01

    Aconcagua (6962 m) is one of the seven summits and the highest mountain outside of Asia. Climbers of varying experience are drawn to its nontechnical route. Our objective was to detail the prior altitude experience of climbers attempting to summit Aconcagua. We asked all climbers on the normal route of Aconcagua to complete questionnaires with demographics and prior high altitude experience while acclimatizing at Plaza de Mulas base camp during 9 nonconsecutive days in January 2009. 127 volunteers from 22 countries were enrolled. Mean age was 39.8 years and 88.2% were male. Median altitude at place of residence was 200 m (IQR: 30, 700). Median previous maximum altitude reached was 5895 m (IQR: 5365, 6150). 7.1% of climbers had never been above 4000 m. Median previous maximum sleeping altitude was 4800 m (IQR: 4300, 5486). 12.6% of climbers had never slept above 4000 m. Climbers who performed acclimatization treks spent a mean of 3.6 (2.5, 4.7) days at>3000 m in the previous 2 months. However, 50.4% of climbers performed no acclimatization treks. Although the majority of mountaineers who attempt Aconcagua have prior high altitude experience, a substantial minority has never been above 4000 m. PMID:22206564

  8. Predator foraging altitudes reveal the structure of aerial insect communities.

    Science.gov (United States)

    Helms, Jackson A; Godfrey, Aaron P; Ames, Tayna; Bridge, Eli S

    2016-01-01

    The atmosphere is populated by a diverse array of dispersing insects and their predators. We studied aerial insect communities by tracking the foraging altitudes of an avian insectivore, the Purple Martin (Progne subis). By attaching altitude loggers to nesting Purple Martins and collecting prey delivered to their nestlings, we determined the flight altitudes of ants and other insects. We then tested hypotheses relating ant body size and reproductive ecology to flight altitude. Purple Martins flew up to 1,889 meters above ground, and nestling provisioning trips ranged up to 922 meters. Insect communities were structured by body size such that species of all sizes flew near the ground but only light insects flew to the highest altitudes. Ant maximum flight altitudes decreased by 60% from the lightest to the heaviest species. Winged sexuals of social insects (ants, honey bees, and termites) dominated the Purple Martin diet, making up 88% of prey individuals and 45% of prey biomass. By transferring energy from terrestrial to aerial food webs, mating swarms of social insects play a substantial role in aerial ecosystems. Although we focus on Purple Martins and ants, our combined logger and diet method could be applied to a range of aerial organisms. PMID:27352817

  9. Time-varying signal analysis to detect high-altitude periodic breathing in climbers ascending to extreme altitude

    OpenAIRE

    Garde, Ainara; Giraldo Giraldo, Beatriz; Jané Campos, Raimon; Latshang, T D; Turk, A.J.; Hess, T.; Bosch, M M; Barthelmes, D.; Merz, T M; Pichler Hefti, J.; Schoch, O.D.; Bloch, Konrad E

    2015-01-01

    This work investigates the performance of cardiorespiratory analysis detecting periodic breathing (PB) in chest wall recordings in mountaineers climbing to extreme altitude. The breathing patterns of 34 mountaineers were monitored unobtrusively by inductance plethysmography, ECG and pulse oximetry using a portable recorder during climbs at altitudes between 4497 and 7546 m on Mt. Muztagh Ata. The minute ventilation (VE) and heart rate (HR) signals were studied, to identify visually scored ...

  10. 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

  11. Transcriptome and network changes in climbers at extreme altitudes.

    Directory of Open Access Journals (Sweden)

    Fang Chen

    Full Text Available Extreme altitude can induce a range of cellular and systemic responses. Although it is known that hypoxia underlies the major changes and that the physiological responses include hemodynamic changes and erythropoiesis, the molecular mechanisms and signaling pathways mediating such changes are largely unknown. To obtain a more complete picture of the transcriptional regulatory landscape and networks involved in extreme altitude response, we followed four climbers on an expedition up Mount Xixiabangma (8,012 m, and collected blood samples at four stages during the climb for mRNA and miRNA expression assays. By analyzing dynamic changes of gene networks in response to extreme altitudes, we uncovered a highly modular network with 7 modules of various functions that changed in response to extreme altitudes. The erythrocyte differentiation module is the most prominently up-regulated, reflecting increased erythrocyte differentiation from hematopoietic stem cells, probably at the expense of differentiation into other cell lineages. These changes are accompanied by coordinated down-regulation of general translation. Network topology and flow analyses also uncovered regulators known to modulate hypoxia responses and erythrocyte development, as well as unknown regulators, such as the OCT4 gene, an important regulator in stem cells and assumed to only function in stem cells. We predicted computationally and validated experimentally that increased OCT4 expression at extreme altitude can directly elevate the expression of hemoglobin genes. Our approach established a new framework for analyzing the transcriptional regulatory network from a very limited number of samples.

  12. Joseph Barcroft's studies of high-altitude physiology.

    Science.gov (United States)

    West, John B

    2013-10-15

    Joseph Barcroft (1872-1947) was an eminent British physiologist who made contributions to many areas. Some of his studies at high altitude and related topics are reviewed here. In a remarkable experiment he spent 6 days in a small sealed room while the oxygen concentration of the air gradually fell, simulating an ascent to an altitude of nearly 5,500 m. The study was prompted by earlier reports by J. S. Haldane that the lung secreted oxygen at high altitude. Barcroft tested this by having blood removed from an exposed radial artery during both rest and exercise. No evidence for oxygen secretion was found, and the combination of 6 days incarceration and the loss of an artery was heroic. To obtain more data, Barcroft organized an expedition to Cerro de Pasco, Peru, altitude 4,300 m, that included investigators from both Cambridge, UK and Harvard. Again oxygen secretion was ruled out. The protocol included neuropsychometric measurements, and Barcroft famously concluded that all dwellers at high altitude are persons of impaired physical and mental powers, an assertion that has been hotly debated. Another colorful experiment in a low-pressure chamber involved reducing the pressure below that at the summit of Mt. Everest but giving the subjects 100% oxygen to breathe while exercising as a climber would on Everest. The conclusion was that it would be possible to reach the summit while breathing 100% oxygen. Barcroft was exceptional for his self-experimentation under hazardous conditions.

  13. Environmental stress and 3-day eventing: effects of altitude.

    Science.gov (United States)

    Foreman, J H; Waldsmith, J K; Lalum, R B

    1999-07-01

    Three-day event horses are subject to various external environmental stresses including changes in ambient temperature, humidity, altitude, and test severity. Considerable research on the adverse effects of increased heat and humidity preceded the 1996 Olympic Summer Games in Atlanta, Georgia USA, but no research has been done previously on the effects of altitude on 3-day eventing. Physical and venous blood gas data were collected on horses (n = 24) competing in the High Prairie Preliminary (CCN*) and Intermediate (CCN**) 3-day events and Preliminary Horse Trials in Parker, Colorado (1900 m above sea level). Despite the increased altitude, only post exercise rectal temperature and pH were higher (P 0.05). When these preliminary horse trial horses in Colorado were compared to those previously studied at preliminary horse trials at sea level in Arizona, post exercise HR and RR were higher (P < 0.05) and pH, PCO2, [tCO2], [HCO3-], BE and [iCa++] were lower (P < 0.05) at altitude. These data show that increased altitude (1900 m above sea level) was more stressful for 3-day event horses, but did not result in the severe physiological changes and inability to complete prescribed exercise tests seen in previous studies with increased heat and humidity. It is clear from these and previous data that increased heat and humidity are the more important environmental stressors in 3-day eventing. PMID:10659288

  14. 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

  15. Modelling circumplanetary ejecta clouds at low altitudes: a probabilistic approach

    CERN Document Server

    Christou, Apostolos A

    2014-01-01

    A model is presented of a ballistic, collisionless, steady state population of ejecta launched at randomly distributed times and velocities and moving under constant gravity above the surface of an airless planetary body. Within a probabilistic framework, closed form solutions are derived for the probability density functions of the altitude distribution of particles, the distribution of their speeds in a rest frame both at the surface and at altitude and with respect to a moving platform such as an orbiting spacecraft. These expressions are validated against numerically-generated synthetic populations of ejecta under lunar surface gravity. The model is applied to the cases where the ejection speed distribution is (a) uniform (b) a power law. For the latter law, it is found that the effective scale height of the ejecta envelope directly depends on the exponent of the power law and increases with altitude. The same holds for the speed distribution of particles near the surface. Ejection model parameters can, t...

  16. Latitudinal dependence of the variability of the micrometeor altitude distribution

    Science.gov (United States)

    Sparks, J. J.; Janches, D.

    2009-06-01

    We present a study of the diurnal behavior of the observed meteor altitude distribution at different seasons and latitudes. The meteor altitude distribution provides an indication of where the meteoric mass deposition occurs in the mesosphere and lower thermosphere (MLT). This can be utilized to model the input of metallic constituents into the MLT and accurately understand the chemistry of this region. We show that the observed altitude distributions have distinct variability at each location: at high latitudes there is a weak diurnal and strong seasonal variability while at tropical latitudes the opposite behavior is observed. We explain these results by correlating them with the astronomical and physical properties of the meteoric flux. Finally, we discussed the potential influences that these results have on the metal chemistry and aeronomy of this atmospheric region.

  17. 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

  18. Hyperuricemia, hypertension, and proteinuria associated with high-altitude polycythemia.

    Science.gov (United States)

    Jefferson, J Ashley; Escudero, Elizabeth; Hurtado, Maria-Elena; Kelly, Jackeline Pando; Swenson, Erik R; Wener, Mark H; Burnier, Michel; Maillard, Marc; Schreiner, George F; Schoene, Robert B; Hurtado, Abdias; Johnson, Richard J

    2002-06-01

    Chronic exposure to high altitude is associated with the development of erythrocytosis, proteinuria, and, in some cases, hyperuricemia. We examined the relationship between high-altitude polycythemia and proteinuria and hyperuricemia in Cerro de Pasco, Peru (altitude, 4,300 m). We studied 25 adult men with hematocrits less than 65% and 27 subjects with excessive erythrocytosis (EE; hematocrit > 65%) living in Cerro de Pasco, Peru and compared them with 28 control subjects living in Lima, Peru (at sea level) and after 48 hours of exposure to high altitude. Serum urate levels were significantly elevated in patients with EE at altitude, and gout occurred in 4 of 27 of these subjects. Urate level strongly correlated with hematocrit (r = 0.71; P < 0.0001). Urate production (24-hour urine urate excretion and urine urate-creatinine ratio) was increased in this group compared with those at sea level. Fractional urate excretion was not increased, and fractional lithium excretion was reduced, in keeping with increased proximal reabsorption of filtrate. Significantly higher blood pressures and decreased renin levels in the EE group were in keeping with increased proximal sodium reabsorption. Serum urate levels correlated with mean blood pressure (r = 0.50; P < 0.0001). Significant proteinuria was more prevalent in the EE group despite normal renal function. Hyperuricemia is common in subjects living at high altitude and associated with EE, hypertension, and proteinuria. The increase in uric acid levels appears to be caused by increased urate generation secondary to systemic hypoxia, although a relative impairment in renal excretion also may contribute.

  19. [Sperm count and seminal biochemistry of high altitude inhabitants and patients with chronic altitude sickness].

    Science.gov (United States)

    García-Hjarles, M A

    1989-04-01

    Semen analysis has been studied in 9 healthy adult males from sea level (150 m), age 19-32 years old and 15 healthy males from high altitude (NA), 9 from Cerro de Pasco (4,300 m) and 6 from Morococha (4,540 m), ages 19-45 years old. Five patients with chronic mountain sickness (MMC), whose ages ranged from 23 to 52 years old were also studied. The volume and motility were similar in NA and MMC, however both were below than in sea level subjects, but still in the normal range; the number of spermatozoa per 1 ml was lower at sea level than in NA and MMC, although the total number was higher at sea level due to the higher semen volume. Fructose at sea level was 356 +/- 53 mg/100 ml (mean +/- S.E.) which is similar to NA 237 +/- 45 whereas a MMC was significantly lower, 142 +/- 60. Citric acid was lower at sea level than in NA and MMC. Na, K and Cl, were similar among the three groups. The lower concentration of fructose in MMC parallels the decreased testicular function already found in these groups. However it is worthy to point out that the fertility is preserved in all the groups. The normal reproductive function in MMC is against the concept that this process occurs as a consequence of environmental disadaptation.

  20. Timing the arrival at 2340m altitude for aerobic performance

    DEFF Research Database (Denmark)

    Schuler, B; Thomsen, JJ; Gassmann, M;

    2007-01-01

    This study tested the hypothesis that maximal oxygen uptake (VO2max) and performance increase upon altitude acclimatization at moderate altitude. Eight elite cyclists were studied at sea level, and after 1 (Day 1), 7 (Day 7), 14 (Day 14) and 21 (Day 21) days of exposure to 2340 m. Capillary blood...... samples were taken on these days before performing two consecutive maximal exercise trials. Acclimatization reased hemoglobin concentration and arterial oxygen content. On Day 1, VO2max and time to exhaustion (at 80% of sea-level maximal power output) decreased by 12.8% (P<0.05) and 25.8% (P<0...

  1. The GRAD high-altitude balloon flight over Antarctica

    International Nuclear Information System (INIS)

    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 56Co 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

  2. Iron Supplementation and Altitude: Decision Making Using a Regression Tree

    Directory of Open Access Journals (Sweden)

    Laura A. Garvican-Lewis, Andrew D. Govus, Peter Peeling, Chris R. Abbiss, Christopher J. Gore

    2016-03-01

    Full Text Available Altitude exposure increases the body’s need for iron (Gassmann and Muckenthaler, 2015, primarily to support accelerated erythropoiesis, yet clear supplementation guidelines do not exist. Athletes are typically recommended to ingest a daily oral iron supplement to facilitate altitude adaptations, and to help maintain iron balance. However, there is some debate as to whether athletes with otherwise healthy iron stores should be supplemented, due in part to concerns of iron overload. Excess iron in vital organs is associated with an increased risk of a number of conditions including cancer, liver disease and heart failure. Therefore clear guidelines are warranted and athletes should be discouraged from ‘self-prescribing” supplementation without medical advice. In the absence of prospective-controlled studies, decision tree analysis can be used to describe a data set, with the resultant regression tree serving as guide for clinical decision making. Here, we present a regression tree in the context of iron supplementation during altitude exposure, to examine the association between pre-altitude ferritin (Ferritin-Pre and the haemoglobin mass (Hbmass response, based on daily iron supplement dose. De-identified ferritin and Hbmass data from 178 athletes engaged in altitude training were extracted from the Australian Institute of Sport (AIS database. Altitude exposure was predominantly achieved via normobaric Live high: Train low (n = 147 at a simulated altitude of 3000 m for 2 to 4 weeks. The remaining athletes engaged in natural altitude training at venues ranging from 1350 to 2800 m for 3-4 weeks. Thus, the “hypoxic dose” ranged from ~890 km.h to ~1400 km.h. Ethical approval was granted by the AIS Human Ethics Committee, and athletes provided written informed consent. An in depth description and traditional analysis of the complete data set is presented elsewhere (Govus et al., 2015. Iron supplementation was prescribed by a sports physician

  3. Acetazolamide improves cerebral oxygenation during exercise at high altitude

    NARCIS (Netherlands)

    Vuyk, J.; Bos, J. van den; Terhell, K.; Bos, R. de; Vletter, A.; Valk, P.; Beuzekom, M. van; Kleef, J. van; Dahan, A.

    2006-01-01

    Acute mountain sickness is thought to be triggered by cerebral hypoxemia and be prevented by acetazolamide (Actz). The effect of Actz on cerebral oxygenation at altitude remains unknown. In 16 members of the 2005 Dutch Cho Oyu (8201 m, Tibet) expedition, the influence of Actz and exercise (750 mg PO

  4. 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 f

  5. Investigating the auroral electrojets with low altitude polar orbiting satellites

    DEFF Research Database (Denmark)

    Moretto, T.; Olsen, Nils; Ritter, P.;

    2002-01-01

    Three geomagnetic satellite missions currently provide high precision magnetic field measurements from low altitude polar orbiting spacecraft. We demonstrate how these data can be used to determine the intensity and location of the horizontal currents that flow in the ionosphere, predominantly in...

  6. Anthropometric and body composition changes during expeditions at high altitude.

    Science.gov (United States)

    Zaccagni, Luciana; Barbieri, Davide; Cogo, Annalisa; Gualdi-Russo, Emanuela

    2014-06-01

    The purpose of this study is to investigate separately in the two sexes the physical adaptations associated to exposure to high altitude in a sample of 18 nonacclimatized Caucasian subjects (10 males and 8 females, 22-59 years) who participated to scientific expeditions to Himalaya up to the Pyramid Laboratory (5050 m, Nepal) or Everest North Base Camp (5300 m, Tibet). Anthropometric traits (body height and weight, eight girths and six skinfolds) were collected according to standard procedures, before departure at sea level, during ascent (at altitude > 4000 m above sea level), and after return to low altitude. Body composition was assessed by means of the skinfold method. Both sexes lost on average 4.0% of initial body mass, corresponding to 7.6% of fat mass and 3.5% of fat free mass in males, and to 5.0% of fat mass and 3.6% of fat free mass in females. Average fat mass loss was greater in males than in females. Initial fat mass percentage was positively correlated to fat mass loss and negatively to FFM loss in males only, thus at HA leanest subjects lost more FFM and less FM than the fattest ones. Adaptations were faster in males than in females. In conclusion, the present research describes significant adaptations to high altitude, in terms of body weight reduction, regardless of the amount of performed physical activity. PMID:24665979

  7. Variation in the isotopic content of precipitation with altitude

    International Nuclear Information System (INIS)

    Monthly precipitation and single storms have been collected during three years at 12 stations along a W-E profile in Chile, going from Juan Fernandez Islands to Valparaiso, Santiago and Infiernillo in the Andes, and analysed for their deuterium content. The deltaD values are correlated with the altitude of the station, the mean temperature - which also largely depends on the altitude - and the distance from the sea. The correlation parameters show however important variations from year to year and even more from month to month. For instance, in the stretch Santiago (520 m a.s.l.) - La Parva (2680 m) the mean isotopic gradient with altitude were: -1.84 deltaD per mil/100 m in 1970, -1.09 in 1971 and -2.0 in 1972. The low value observed in 1971 could be a consequence of the peculiar weather characteristics of this unusually dry year. In the stretch from the coast to Santiago the trend of the isotopic composition of precipitation is more complicated, because the so-called continental effect is superimposed to the altitude effect. The deuterium content variations have been also determined in snowpack profiles at La Parva station. The results show that snow melting occurs slowly at the bottom during the whole winter, at the expenses of the heat stored during summer in the soil. The melting of the surface snow layers only starts at the end of the winter and then proceeds very fast

  8. 77 FR 71735 - Minimum Altitudes for Use of Autopilots

    Science.gov (United States)

    2012-12-04

    ... change in present value, but not in total cost, because this type of training would have occurred in the... systems at current autopilot minimum use altitudes. The proposed rule would accomplish this through a... the Federal Register published on April 11, 2000 (65 FR 19477-19478), as well as at...

  9. 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.

  10. The genetic architecture of adaptations to high altitude in Ethiopia.

    Science.gov (United States)

    Alkorta-Aranburu, Gorka; Beall, Cynthia M; Witonsky, David B; Gebremedhin, Amha; Pritchard, Jonathan K; Di Rienzo, Anna

    2012-01-01

    Although hypoxia is a major stress on physiological processes, several human populations have survived for millennia at high altitudes, suggesting that they have adapted to hypoxic conditions. This hypothesis was recently corroborated by studies of Tibetan highlanders, which showed that polymorphisms in candidate genes show signatures of natural selection as well as well-replicated association signals for variation in hemoglobin levels. We extended genomic analysis to two Ethiopian ethnic groups: Amhara and Oromo. For each ethnic group, we sampled low and high altitude residents, thus allowing genetic and phenotypic comparisons across altitudes and across ethnic groups. Genome-wide SNP genotype data were collected in these samples by using Illumina arrays. We find that variants associated with hemoglobin variation among Tibetans or other variants at the same loci do not influence the trait in Ethiopians. However, in the Amhara, SNP rs10803083 is associated with hemoglobin levels at genome-wide levels of significance. No significant genotype association was observed for oxygen saturation levels in either ethnic group. Approaches based on allele frequency divergence did not detect outliers in candidate hypoxia genes, but the most differentiated variants between high- and lowlanders have a clear role in pathogen defense. Interestingly, a significant excess of allele frequency divergence was consistently detected for genes involved in cell cycle control and DNA damage and repair, thus pointing to new pathways for high altitude adaptations. Finally, a comparison of CpG methylation levels between high- and lowlanders found several significant signals at individual genes in the Oromo.

  11. Martian high-altitude photoelectrons independent of solar zenith angle

    Science.gov (United States)

    Xu, Shaosui; Liemohn, Michael; Bougher, Stephen; Mitchell, David

    2016-04-01

    Many aspects of the Martian upper atmosphere are known to vary with solar zenith angle (SZA). One would assume that dayside photoelectron fluxes are also SZA dependent, especially when transport along a semivertical magnetic field line is significant. However, our investigation presented here of the observed Martian high-altitude (˜400 km) photoelectron fluxes by the magnetometer/electron reflectometer (MAG/ER) instruments on board Mars Global Surveyor (MGS) shows that the photoelectron fluxes are better correlated with just the solar irradiance, without SZA factored in, and also that the median photoelectron fluxes are independent of SZA, especially for high energies (above 100 eV). For lower energies (below 70 eV), the observed fluxes tend to vary to some degree with SZA. Such counterintuitive results are due to the existence of a photoelectron exobase, only above which the photoelectrons are able to transport and escape to high altitudes. Two methods are used here to determine the altitude range of this exobase, which varies between 145 km and 165 km depending on the atmosphere and SZA. Through our SuperThermal Electron Transport (STET) model, we found that the integral of the production rate above the photoelectron exobase, and therefore the high-altitude photoelectron fluxes, is rather independent of SZA. Such an independent relationship concerns energy redistribution in the Martian upper atmosphere, using photoelectrons to map magnetic topology and connectivity, as well as ion escape. This finding can also be carefully adapted to other solar bodies with semivertical magnetic fields at ionospheric altitudes, such as Earth, Jupiter, and Saturn.

  12. Effect of altitude on the protein metabolism of Bolivian children

    International Nuclear Information System (INIS)

    The malnutrition is prevalent and is a major problem among Bolivian children. It is caused by several interacting factors: (1) inadequate protein energy intake due to low socio-economic status; (ii) exposure to acute, repeated and chronic bacterial infections; (iii) exposure to multiple and chronic parasitic infections; (iv) high altitude of the capital, La Paz, 3600 m, with a numerous populations compared to the rest of the country. The research objectives in the first phase are: (i) determination of protein utilization with a non-invasive method using stable isotope tracer among children living at high and low altitude; (ii) determination of protein metabolism among eutrophic children without parasitic or acute bacterial infections at both altitudes; (iii) determination of protein requirement among these children. Two groups of 10 pubertal children, matched for age and sex, of same socio-economic status, eutrophic, without malnutrition, infections or intestinal parasites will be studied; the different status being arrived by anthropometric, nutritional intake, biochemical and pediatrical evaluation. For the metabolic study, stable isotopes L-[1-13C] leucine labelled casein will be used and 13CO2 excreted will be measured. All the basic nutritional assessment and VCO2 measurements will be performed in Bolivia, while the samples of expired gas will be stored in Vacutainers for further analysis by isotope radio mass spectrometer (IRMS), in Clermont-Ferrand, France. The plans for future work is based on the study of the effects of the different variables and their interactions. The following will be evaluated: (i) the socio-economic status; (ii) the bacterial infections: (iii) the parasitic infections; (iv) the altitude. As published by Obert, et al., the socio-economic variable is more connected with the nutritional status than with the altitude. 12 refs, 1 fig., 1 tab

  13. Surface altitude of hydrogeologic layers of the Atlantic Coastal Plain of North and South Carolina

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — PP1773_unit_alt_grid is a polygon shapefile of surface altitudes for 16 hydrogeologic units as described in report Professional Paper 1773. Surface altitudes were...

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

    Data.gov (United States)

    National Aeronautics and Space Administration — High-altitude balloon flights are an inexpensive method used to lift payloads to high altitudes. Federal Aviation Administration (FAA) regulations permit payloads...

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

    International Nuclear Information System (INIS)

    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)

  16. First year results of the High Altitude Water Cherenkov observatory

    CERN Document Server

    Carramiñana, Alberto

    2016-01-01

    The High Altitude Water Cherenkov (HAWC) gamma-ray observatory is a wide field of view (1.8 Sr) and high duty cycle (>95% up-time) detector of unique capabilities for the study of TeV gamma-ray sources. Installed at an altitude of 4100m in the Northern slope of Volc\\'an Sierra Negra, Puebla, by a collaboration of about thirty institutions of Mexico and the United States, HAWC has been in full operations since March 2015, surveying 2/3 of the sky every sidereal day, monitoring active galaxies and mapping sources in the Galactic Plane to a detection level of 1 Crab per day. This contribution summarizes the main results of the first year of observations of the HAWC gamma-ray observatory.

  17. Altitude Variations of the Peak Auroral Emissions within Auroral Structures

    Science.gov (United States)

    Sangalli, L.

    2015-12-01

    The MIRACLE network monitors auroral activity in the Fennoscandian sector of Europe. Network stations cover the range of 55° to 57° magnetic latitude North and span two hours in magnetic local time. Some of the MIRACLE network stations include digital all-sky cameras (ASC) with overlapping field-of-views located at the latitude aurora occurs. The ASCs in this network operate at three different wavelengths: 427.8 nm (blue line), 557.7 nm (green line) and 630.0 nm (red line). These wavelengths are selected using narrow band filters. The new ASC systems are based on electron multiplying CCDs (emCCD), which allow higher time and spatial resolutions. The peak auroral emission altitude is determined using two ASC images from a station pair. Different auroral events are used to evaluate the altitude variations of the peak auroral emissions within auroral structures and its evolution in time.

  18. Cosmic Microwave Background Science at Commercial Airline Altitudes

    CERN Document Server

    Feeney, Stephen M; Peiris, Hiranya V; Verde, Licia; Errard, Josquin

    2016-01-01

    Obtaining high-sensitivity measurements of degree-scale cosmic microwave background (CMB) polarization is the most direct path to detecting primordial gravitational waves. Robustly recovering any primordial signal from the dominant foreground emission will require high-fidelity observations at multiple frequencies, with excellent control of systematics. We explore the potential for a new platform for CMB observations, the Airlander 10 hybrid air vehicle, to perform this task. We show that the Airlander 10 platform, operating at commercial airline altitudes, is well-suited to mapping frequencies above 220 GHz, which are critical for cleaning CMB maps of dust emission. Optimizing the distribution of detectors across frequencies, we forecast the ability of Airlander 10 to clean foregrounds of varying complexity as a function of altitude, demonstrating its complementarity with both existing (Planck) and ongoing (C-BASS) foreground observations. This novel platform could play a key role in defining our ultimate vi...

  19. 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...... 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...... difference between Tibetan and Han samples, representing the fastest allele frequency change observed at any human gene to date. This SNP's association with erythrocyte abundance supports the role of EPAS1 in adaptation to hypoxia. Thus, a population genomic survey has revealed a functionally important locus...

  20. Initial Feasibility Assessment of a High Altitude Long Endurance Airship

    Science.gov (United States)

    Colozza, Anthony; Dolce, James (Technical Monitor)

    2003-01-01

    A high altitude solar powered airship provides the ability to carry large payloads to high altitudes and remain on station for extended periods of time. This study examines the feasibility of this concept. Factors such as time of year, latitude, wind speeds and payload are considered in establishing the capabilities of a given size airship. East and West coast operation were evaluated. The key aspect to success of this type of airship is the design and operation of the propulsion and power system. A preliminary propulsion/power system design was produced based on a regenerative fuel cell energy storage system and solar photovoltaic array for energy production. A modular system design was chosen with four independent power/propulsion units utilized by the airship. Results on payload capacity and flight envelope (latitude and time of year) were produced for a range of airship sizes.

  1. 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...... streams from sea level to 4000 m a.s.l. in Ecuador, we determined predicted oxygen availability, oxygen demand and macroinvertebrate assemblage structure along this wide altitudinal gradient. 3. We show that the predicted oxygen availability at 4000 m a.s.l. is only one fifth of that at sea level, whereas...... relatively few groups normally regarded as oxygen-sensitive. Nevertheless, high altitude assemblages react more strongly to lowering of oxygen saturation, and are thus more sensitive to organic pollution. 5. Oxygen deficiency has been overlooked completely in studies of the altitudinal distribution...

  2. Population variation revealed high-altitude adaptation of Tibetan mastiffs.

    Science.gov (United States)

    Li, Yan; Wu, Dong-Dong; Boyko, Adam R; Wang, Guo-Dong; Wu, Shi-Fang; Irwin, David M; Zhang, Ya-Ping

    2014-05-01

    With the assistance of their human companions, dogs have dispersed into new environments during the expansion of human civilization. Tibetan Mastiff (TM), a native of the Tibetan Plateau, was derived from the domesticated Chinese native dog and, like Tibetans, has adapted to the extreme environment of high altitude. Here, we genotyped genome-wide single-nucleotide polymorphisms (SNPs) from 32 TMs and compared them with SNPs from 20 Chinese native dogs and 14 gray wolves (Canis lupus). We identified 16 genes with signals of positive selection in the TM, with 12 of these candidate genes associated with functions that have roles in adaptation to high-altitude adaptation, such as EPAS1, SIRT7, PLXNA4, and MAFG that have roles in responses to hypoxia. This study provides important information on the genetic diversity of the TM and potential mechanisms for adaptation to hypoxia. PMID:24520091

  3. Altitude Training and its Influence on Physical Endurance in Swimmers

    OpenAIRE

    Strzała, Marek; Ostrowski, Andrzej; Szyguła, Zbigniew

    2011-01-01

    It is possible to plan an altitude training (AT) period in such a way that the enhanced physical endurance obtained as a result of adaptation to hypoxia will appear and can be used to improve performance in competition. Yet finding rationales for usage of AT in highly trained swimmers is problematic. In practice AT, in its various forms, is still controversial, and an objective review of research concentrating on the advantages and disadvantages of AT has been presented in several scientific ...

  4. Animal-habitat relationships in high altitude rangelands

    OpenAIRE

    Singh, Navinder J.

    2008-01-01

    This study conducted in the high altitude rangelands of Indian Transhimalaya, deals with basic questions regarding the ecology of an endangered species, the wildsheep Tibetan argali (Ovis ammon hodgsoni) and applied issues related to its conservation and potential conflict with the local nomadic pastoralists. The basic questions on ecology are aimed at delineating the habitat and resource selection processes, identifying factors causing sexual segregation and efficient surveyin...

  5. Altitude Training: Strong Bounds for Single-Layer Dropout

    OpenAIRE

    Wager, Stefan; Fithian, William; Wang, Sida; Liang, Percy

    2014-01-01

    Dropout training, originally designed for deep neural networks, has been successful on high-dimensional single-layer natural language tasks. This paper proposes a theoretical explanation for this phenomenon: we show that, under a generative Poisson topic model with long documents, dropout training improves the exponent in the generalization bound for empirical risk minimization. Dropout achieves this gain much like a marathon runner who practices at altitude: once a classifier learns to perfo...

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

    OpenAIRE

    Shah NM; Hussain S; Cooke M.; O’Hara JP; Mellor A

    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...

  7. The genetic architecture of adaptations to high altitude in Ethiopia.

    Directory of Open Access Journals (Sweden)

    Gorka Alkorta-Aranburu

    Full Text Available Although hypoxia is a major stress on physiological processes, several human populations have survived for millennia at high altitudes, suggesting that they have adapted to hypoxic conditions. This hypothesis was recently corroborated by studies of Tibetan highlanders, which showed that polymorphisms in candidate genes show signatures of natural selection as well as well-replicated association signals for variation in hemoglobin levels. We extended genomic analysis to two Ethiopian ethnic groups: Amhara and Oromo. For each ethnic group, we sampled low and high altitude residents, thus allowing genetic and phenotypic comparisons across altitudes and across ethnic groups. Genome-wide SNP genotype data were collected in these samples by using Illumina arrays. We find that variants associated with hemoglobin variation among Tibetans or other variants at the same loci do not influence the trait in Ethiopians. However, in the Amhara, SNP rs10803083 is associated with hemoglobin levels at genome-wide levels of significance. No significant genotype association was observed for oxygen saturation levels in either ethnic group. Approaches based on allele frequency divergence did not detect outliers in candidate hypoxia genes, but the most differentiated variants between high- and lowlanders have a clear role in pathogen defense. Interestingly, a significant excess of allele frequency divergence was consistently detected for genes involved in cell cycle control and DNA damage and repair, thus pointing to new pathways for high altitude adaptations. Finally, a comparison of CpG methylation levels between high- and lowlanders found several significant signals at individual genes in the Oromo.

  8. 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.

  9. Measurement and Characterization of Helicopter Noise at Different Altitudes

    Science.gov (United States)

    Watts, Michael E.; Greenwood, Eric; Stephenson, James

    2016-01-01

    This paper presents an overview of a flight test campaign performed at different test sites whose altitudes ranged from 0 to 7000 feet above mean sea level (AMSL) between September 2014 and February 2015. The purposes of this campaign were to: investigate the effects of altitude variation on noise generation, investigate the effects of gross weight variation on noise generation, establish the statistical variability in acoustic flight testing of helicopters, and characterize the effects of transient maneuvers on radiated noise for a medium-lift utility helicopter. In addition to describing the test campaign, results of the acoustic effects of altitude variation for the AS350 SD1 and EH-60L aircraft are presented. Large changes in acoustic amplitudes were observed in response to changes in ambient conditions when the helicopter was flown at constant indicated airspeed and gross weight at the three test sites. However, acoustic amplitudes were found to scale with ambient pressure when flight conditions were defined in terms of the non-dimensional parameters, such as the weight coefficient and effective hover tip Mach number.

  10. Decompression to altitude: assumptions, experimental evidence, and future directions.

    Science.gov (United States)

    Foster, Philip P; Butler, Bruce D

    2009-02-01

    Although differences exist, hypobaric and hyperbaric exposures share common physiological, biochemical, and clinical features, and their comparison may provide further insight into the mechanisms of decompression stress. Although altitude decompression illness (DCI) has been experienced by high-altitude Air Force pilots and is common in ground-based experiments simulating decompression profiles of extravehicular activities (EVAs) or astronauts' space walks, no case has been reported during actual EVAs in the non-weight-bearing microgravity environment of orbital space missions. We are uncertain whether gravity influences decompression outcomes via nitrogen tissue washout or via alterations related to skeletal muscle activity. However, robust experimental evidence demonstrated the role of skeletal muscle exercise, activities, and/or movement in bubble formation and DCI occurrence. Dualism of effects of exercise, positive or negative, on bubble formation and DCI is a striking feature in hypobaric exposure. Therefore, the discussion and the structure of this review are centered on those highlighted unresolved topics about the relationship between muscle activity, decompression, and microgravity. This article also provides, in the context of altitude decompression, an overview of the role of denitrogenation, metabolic gases, gas micronuclei, stabilization of bubbles, biochemical pathways activated by bubbles, nitric oxide, oxygen, anthropometric or physiological variables, Doppler-detectable bubbles, and potential arterialization of bubbles. These findings and uncertainties will produce further physiological challenges to solve in order to line up for the programmed human return to the Moon, the preparation for human exploration of Mars, and the EVAs implementation in a non-zero gravity environment.

  11. Distribution of ionospheric O+ion in synchronous altitude region

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Based on satellite observation data, using dynamics equation, the ionospheric O+ion's distribution in the synchronous altitude region for different geomagnetic activity index Kp is studied by theoretical modeling and numerical analyzing, and semi-empirical models for the O+ion's density and flux versus longitude in the synchronous altitude region for different Kp are given. The main results show that in the synchronous altitude region:(i) The O+ ion's density andflux in dayside are larger than those in nightside.(ii) With longitude changing, the higher the geomagnetic activity index Kp is, the higher the O+ion's density and flux, and their variation amplitude will be. The O+ion's density and flux when Kp ≥ 6 will be about ten times as great as that when Kp = 0.(iii) When Kp = 0 or Kp ≥ 6, the O+ion's density reaches maximum at longitudes 120°and240°respectively, and minimum in the magnetotail. When Kp = 3-5, the O+ion'sdensity gets to maximum at longitude 0°, and minimum in the magnetotail. However, the O+ ion's flux reaches maximum at longitude 120°and 240°respectively, and minimum in the magnetotail for any Kp value.

  12. Altitude Correction for Breakdown Voltages of Long Air-Gaps

    Institute of Scientific and Technical Information of China (English)

    Wang Xuan; Li Yunge; Cao Xiaolong; Su Zhiyi; Liu Ying

    2006-01-01

    The breakdown voltage of long air-gaps in high-voltage transmission systems depends on not only the waveform of the applied voltage, but also the atmospheric conditions. Based on the results of the research project on the minimum air clearance for 800-Kv HVDC substations at high altitudes, and also on the monthly and yearly statistics of the atmospheric data of last ten years and the altitude correction of the atmospheric data of last ten years, the altitude correction of the air-gaps for the 800-Kv DC system under plan, 500-Kv AC system to be built, and 1000-Kv AC system under plan in the Inner Mongolia Plateau and the Yungui Plateau in China were studied with parameter G method. Correction factors for switching and lightning impulses were calculated and then compared with those achieved according to IEC 71. It is shown that IEC 71 is appropriate for damp regions, and correction factors differ between plateau regions in China because of different atmospheric conditions.

  13. The individual response to training and competition at altitude.

    Science.gov (United States)

    Chapman, Robert F

    2013-12-01

    Performance in athletic activities that include a significant aerobic component at mild or moderate altitudes shows a large individual variation. Physiologically, a large portion of the negative effect of altitude on exercise performance can be traced to limitations of oxygen diffusion, either at the level of the alveoli or the muscle microvasculature. In the lung, the ability to maintain arterial oxyhaemoglobin saturation (SaO₂) appears to be a primary factor, ultimately influencing oxygen delivery to the periphery. SaO₂ in hypoxia can be defended by increasing ventilatory drive; however, during heavy exercise, many athletes demonstrate limitations to expiratory flow and are unable to increase ventilation in hypoxia. Additionally, increasing ventilatory work in hypoxia may actually be negative for performance, if dyspnoea increases or muscle blood flow is reduced secondary to an increased sympathetic outflow (eg, the muscle metaboreflex response). Taken together, some athletes are clearly more negatively affected during exercise in hypoxia than other athletes. With careful screening, it may be possible to develop a protocol for determining which athletes may be the most negatively affected during competition and/or training at altitude. PMID:24282206

  14. Space environment monitoring by low-altitude operational satellites

    International Nuclear Information System (INIS)

    The primary task of the Defense Meteorological Satellite Program (DMSP) is the acquisition of meteorological data in the visual and infrared spectral regions. The Air Weather Service operates two satellites in low-altitude, sun-synchronous, polar orbits at 850 km altitude, 98.7 deg inclination, 101.5 minute period and dawn-dusk or noon-midnight equatorial crossing times. Special DMSP sensors of interest to the space science community are the precipitating electron spectrometer, the terrestrial noise receiver, and the topside ionosphere plasma monitor. Data from low-altitude, meteorological satellites can be used to build empirical models of precipitating electron characteristics of the auroral zone and polar cap. The Tiros-NOAA satellite program complements the DMSP program. The orbital elements are the same as DMSP's, except for the times of equatorial crossing, and the tilt of the orbital plane. The Tiros-NOAA program meets the civilian community's needs for meteorological data as the DMSP program does for the military

  15. Diurnal variations of serum erythropoietin at sea level and altitude

    DEFF Research Database (Denmark)

    Klausen, T; Poulsen, T D; Fogh-Andersen, N;

    1996-01-01

    This study tested the hypothesis that the diurnal variations of serum-erythropoietin concentration (serum-EPO) observed in normoxia also exist in hypoxia. The study also attempted to investigate the regulation of EPO production during sustained hypoxia. Nine subjects were investigated at sea level...... and during 4 days at an altitude of 4350 m. Median sea level serum-EPO concentration was 6 (range 6-13) U.l-1. Serum-EPO concentration increased after 18 and 42 h at altitude, [58 (range 39-240) and 54 (range 36-340) U.l-1, respectively], and then decreased after 64 and 88 h at altitude [34 (range 18......-290) and 31 (range 17-104) U.l-1, respectively]. These changes of serum-EPO concentration were correlated to the changes in arterial blood oxygen saturation (r = -0.60, P = 0.0009), pH (r = 0.67, P = 0.003), and in-vivo venous blood oxygen half saturation tension (r = -0.68, P = 0.004) but not to the changes...

  16. Breathing in thin air: acclimatization to altitude in ducks.

    Science.gov (United States)

    Powell, Frank L; Shams, Hashim; Hempleman, Steven C; Mitchell, Gordon S

    2004-12-15

    We measured ventilation (VI) and arterial blood gases in Pekin ducks during acclimatization to 3800 m altitude for 1-90 days. Four experimental series were conducted over 4 years using both natural altitude and a hypobaric chamber. PaCO2 decreased to 3.5 Torr, relative to the value measured during acute hypoxia after 1 day and remained at this level for up to 90 days. However, PaO2 did not increase. Arterial pH showed an unexpected metabolic alkalosis during the first hours at altitude but after 3 days, a metabolic acidosis partially compensated the respiratory alkalosis and pHa was constant thereafter. When normoxia was restored after hypoxia, PaCO2 was 5.5 Torr less than the original normoxic control value, but PaO2 was not increased. VI showed variable changes during acclimatization but if metabolic rate was constant in our study, as reported by others, then effective parabronchial V(VP) increased during acclimatization. Increased VP tends to restore PaO2 toward normoxic levels and decreases adverse effects of gas exchange limitation, which apparently increased during acclimatization in ducks.

  17. Elevated Suicide Rates at High Altitude: Sociodemographic and Health Issues May Be to Blame

    Science.gov (United States)

    Betz, Marian E.; Valley, Morgan A.; Lowenstein, Steven R.; Hedegaard, Holly; Thomas, Deborah; Stallones, Lorann; Honigman, Benjamin

    2011-01-01

    Suicide rates are higher at high altitudes; some hypothesize that hypoxia is the cause. We examined 8,871 suicides recorded in 2006 in 15 states by the National Violent Death Reporting System, with the victim's home county altitude determined from the National Elevation Dataset through FIPS code matching. We grouped cases by altitude (low less…

  18. Altitude acclimatization and blood volume: effects of exogenous erythrocyte volume expansion

    DEFF Research Database (Denmark)

    Sawka, M N; Young, Jette Feveile; Rock, P B;

    1996-01-01

    blood oxygen content alters erythropoietin responses during altitude acclimatization, and 4) mechanisms responsible for plasma loss at altitude. Sixteen healthy men had a series of hematologic measurements made at sea level, on the first and ninth days of altitude (4,300 m) residence, and after...

  19. Polymorphism profiling of nine high altitude relevant candidate gene loci in acclimatized sojourners and adapted natives

    OpenAIRE

    Tomar, Arvind; Malhotra, Seema; Sarkar, Soma

    2015-01-01

    Background Sea level sojourners, on ascent to high altitude, undergo acclimatization through integrated physiological processes for defending the body against oxygen deprivation while the high altitude natives (resident population) are adapted to the prevailing hypobaric hypoxic condition through natural selection. Separating the acclimatization processes from adaptive changes and identifying genetic markers in lowlanders that may be beneficial for offsetting the high altitude hypoxic stress,...

  20. Regression of Body Density on Skinfold Thicknesses in High Altitude Natives: Decline in the Predictive Efficiency on De-Acclimatisation to Low Altitude

    OpenAIRE

    H. Bharadwaj; T. Zachariah; S. Kishnani; S. N. Pramanik; Prasad, J.; K.L. Chaudhary; G. P. Dimri; T. L. Rao; W. Selvamurthy

    1995-01-01

    Body density, stature, body weight and skinfold thickness at 11 sites were experimentally measured on two groups of high altitude natives (HAN) of Ladakh. Group 1, consisting of 38 similar volunteers was studied after 4-week stay at an altitude of 3658 m and Group 2, consisting of 38 similar volunteers was studied after 4-week stay at Delhi (altitude, 200m). Although, there was a strong relationship between skinfolds, other anthropometric measurements and body density (R=0.898) at high...

  1. Lightweight Liquid Helium Dewar for High-Altitude Balloon Payloads

    Science.gov (United States)

    Kogut, Alan; James, Bryan; Fixsen, Dale

    2013-01-01

    Astrophysical observations at millimeter wavelengths require large (2-to-5- meter diameter) telescopes carried to altitudes above 35 km by scientific research balloons. The scientific performance is greatly enhanced if the telescope is cooled to temperatures below 10 K with no emissive windows between the telescope and the sky. Standard liquid helium bucket dewars can contain a suitable telescope for telescope diameter less than two meters. However, the mass of a dewar large enough to hold a 3-to-5-meter diameter telescope would exceed the balloon lift capacity. The solution is to separate the functions of cryogen storage and in-flight thermal isolation, utilizing the unique physical conditions at balloon altitudes. Conventional dewars are launched cold: the vacuum walls necessary for thermal isolation must also withstand the pressure gradient at sea level and are correspondingly thick and heavy. The pressure at 40 km is less than 0.3% of sea level: a dewar designed for use only at 40 km can use ultra thin walls to achieve significant reductions in mass. This innovation concerns new construction and operational techniques to produce a lightweight liquid helium bucket dewar. The dewar is intended for use on high-altitude balloon payloads. The mass is low enough to allow a large (3-to-5-meter) diameter dewar to fly at altitudes above 35 km on conventional scientific research balloons without exceeding the lift capability of the balloon. The lightweight dewar has thin (250- micron) stainless steel walls. The walls are too thin to support the pressure gradient at sea level: the dewar launches warm with the vacuum space vented continuously during ascent to eliminate any pressure gradient across the walls. A commercial 500-liter storage dewar maintains a reservoir of liquid helium within a minimal (hence low mass) volume. Once a 40-km altitude is reached, the valve venting the vacuum space of the bucket dewar is closed to seal the vacuum space. A vacuum pump then

  2. Ataxia, acute mountain sickness, and high altitude cerebral edema

    Institute of Scientific and Technical Information of China (English)

    Wu Tianyi; Ma Siqing; Bian Huiping; Zhang Minming

    2013-01-01

    Previous investigations suggest that ataxia is common and often one of the most reliable warning signs of high altitude cerebral edema(HACE).The aim of this study was to investigate the diagnostic role of ataxia in acute mountain sickness (AMS) and HACE among mountain rescuers on the quake areas,and in approaching the relation between AMS and HACE.After the earthquake on April 14,2010,approximately 24080 lowland rescuers were rapidly transported from sea level or lowlands to the mountainous rescue sites at 3750 ~ 4568 m,and extremely hardly worked for an emergency treatment after arrival.Assessments of acute altitude illness on the quake areas were using the Lake Louise Scoring System.73 % of the rescuers were found to be developed AMS.The incidence of high altitude pulmonary edema(HAPE) and HACE was 0.73 % and 0.26 %,respectively,on the second to third day at altitude.Ataxia sign was measured by simple tests of coordination including a modified Romberg test.The clinical features of 62 patients with HACE were analyzed.It was found that the most frequent,serious neurological symptoms and signs were altered mental status(50/62,80.6 %)and truncal ataxia (47/62,75.8 %).Mental status change was rated slightly higher than ataxia,but ataxia occurred earlier than mental status change and other symptoms.The earliest sign of ataxia was a vague unsteadiness of gait,which may be present alone in association with or without AMS.Advanced ataxia was correlated with the AMS scores,but mild ataxia did not correlate with AMS scores at altitudes of 3750~4568 m.Of them,14 patients were further examined by computerized tomographic scanning of the brain and cerebral magnetic resonance imagines were examined in another 15 cases.These imaging studies indicated that the presence of the cerebral edema was in 97 % of cases who were clinically diagnosed as HACE (28/29).Ataxia seems to be a reliable sign of advanced AMS or HACE,so does altered mental status.

  3. Phase offsets between core and conal components of radio pulsars and their emission altitudes

    CERN Document Server

    Kapoor, R C

    2002-01-01

    We present a new method for investigating emission altitudes of radio pulsar core and conal components by attributing them different altitudes and by providing a framework to understand the resulting longitude offsets between them which are frequently observed. By investigating the contributions to these offsets due to aberration and the magnetic field line sweepback, we show that they are always dominated by aberration for all emission altitudes and inclination angles. This directly allows the conclusion that the core emission does not necessarily come from the surface. Our results and the observational trends imply that for a large number of pulsars the emission altitudes of core and conal components are close when compared to the light cylinder radius but not necessarily relative to the stellar radius. The core/cone altitude differences that we find are typically larger than the individual altitudes ascribed to them so far. Widely different core/cone altitudes for some pulsars are also supported by data an...

  4. Global dust altitude climatology based on CALIPSO observations

    Science.gov (United States)

    Tsamalis, C.; Chedin, A.; Peyridieu, S.

    2011-12-01

    Dust aerosols are important constituents of the earth climate as they influence many processes of the planet. They affect the earth's radiative budget via the direct, the indirect and the semi-direct effects, which cause the modification of the mesoscale dynamics at short time scales and the climate change at long time scales, they act as cloud condensation and ice nuclei and therefore have strong implications in the hydrological cycle, their deposition in the ocean supplies it with nutrients, which in turn affect the ocean biogeochemistry, they impact the atmospheric concentrations of trace gases, via heterogeneous reactions, they contribute to air pollution and they degrade the restitution of atmospheric or surface parameters from satellite instruments. An important parameter of the dust aerosols is their altitude as it defines their impact on the aforementioned processes. But this parameter is not easily measurable except from lidars and more recently from passive infrared remote sensors. Nevertheless, ground based lidars are situated at specific locations and cannot offer a global view of the dust altitude, while dedicated campaigns using lidars and in situ measurements are restricted in time. On the other hand, the passive instruments AIRS or IASI offer a good spatial coverage, but their new established results need further validation. Launched in April 2006, the satellite CALIPSO, with the on board two wavelength depolarisation lidar CALIOP, permits an accurate determination of the aerosols altitude. Moreover, the depolarisation at 532 nm allows the discrimination between dust and other types of aerosols, which generally do not depolarize light. Nevertheless, the beam diameter of 70 m at the earth's surface makes it difficult to interpret statistically the results, as the 16 days repetition cycle of CALIPSO does not cover all the earth. In order to overcome this difficulty, the L2 5 km aerosol layer product (version 3.01) is used here to calculate the

  5. Los primeros contactos de los europeos con las grandes altitudes

    OpenAIRE

    Mas Galvañ, Cayetano

    2011-01-01

    Uno de los aspectos menos conocidos en el proceso de la expansión mundial europea es el del contacto con las altas cadenas montañosas americanas y asiáticas (Andes e Himalaya), y en especial la penetración en las grandes altitudes, superiores a 4.000 metros. En este trabajo se analizan las principales fuentes relacionadas con la presencia de europeos por encima de esas cotas, en el doble terreno de la percepción subjetiva y los episodios de mal agudo de montaña, y en el del avance en la medic...

  6. Impact of Altitude on Power Output during Cycling Stage Racing

    OpenAIRE

    Garvican-Lewis, Laura A; Clark, Bradley; Martin, David T.; Schumacher, Yorck Olaf; McDonald, Warren; Stephens, Brian; Ma, Fuhai; Kevin G Thompson; Gore, Christopher J.; Menaspà, Paolo

    2015-01-01

    Purpose The purpose of this study was to quantify the effects of moderate-high altitude on power output, cadence, speed and heart rate during a multi-day cycling tour. Methods Power output, heart rate, speed and cadence were collected from elite male road cyclists during maximal efforts of 5, 15, 30, 60, 240 and 600 s. The efforts were completed in a laboratory power-profile assessment, and spontaneously during a cycling race simulation near sea-level and an international cycling race at mode...

  7. CAPACITY CALCULATION OF TD-CDMA HIGH ALTITUDE PLATFORM SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Wang Zhenyong; Liu Xiaowei; Li Zhuoshi

    2011-01-01

    A capacity calculation method of High Altitude Platform System (HAPS) is proposed in which TD-CDMA multiple access schemes are applied.With the influence of both power limit and bandwidth limit on capacity integrated,the paper derives the equations by which the capacity of TD-CDMA systems can be calculated,and performs calculation on a practical system.This calculation method is quite simple and effective with a comparatively small error,which is essential to the designing and research on HAPS.

  8. Transcriptome and network changes in climbers at extreme altitudes

    DEFF Research Database (Denmark)

    Chen, Fang; Zhang, Wei; Liang, Yu;

    2012-01-01

    increased erythrocyte differentiation from hematopoietic stem cells, probably at the expense of differentiation into other cell lineages. These changes are accompanied by coordinated down-regulation of general translation. Network topology and flow analyses also uncovered regulators known to modulate...... hypoxia responses and erythrocyte development, as well as unknown regulators, such as the OCT4 gene, an important regulator in stem cells and assumed to only function in stem cells. We predicted computationally and validated experimentally that increased OCT4 expression at extreme altitude can directly...

  9. Diurnal variations of serum erythropoietin at sea level and altitude

    DEFF Research Database (Denmark)

    Klausen, T; Poulsen, T D; Fogh-Andersen, N;

    1996-01-01

    This study tested the hypothesis that the diurnal variations of serum-erythropoietin concentration (serum-EPO) observed in normoxia also exist in hypoxia. The study also attempted to investigate the regulation of EPO production during sustained hypoxia. Nine subjects were investigated at sea level...... concentrations occurred at 0400 hours [31 (range 20-38) U.l-1, P = 0.02]. This study demonstrated diurnal variations of serum-EPO concentration in normoxia and hypoxia, with comparable time courses of median values. The results also suggested that EPO production at altitude is influenced by changes in p...

  10. DETECTION OF JOVIAN RADIO BURSTS AT HIGH ALTITUDES

    Directory of Open Access Journals (Sweden)

    A. SARKAR

    2012-06-01

    Full Text Available In this paper the formation of Jovian magnetosphere has been critically discussed with special emphasis on decametric radio source. Emission of radio signals originating in Jupiter magnetic field and the selection of frequency for detecting the bursts have been considered. The meteorology of the high altitude observing station Darjeeling including the GPS data taken at the observatory has been presented. The Jove receiver used for the reception of radio signals and the technique employed for the detection of bursts are also outlined in this preliminary report.

  11. the APL Balloonborne High Altitude Research Platform (HARP)

    Science.gov (United States)

    Adams, D.; Arnold, S.; Bernasconi, P.

    2015-09-01

    The Johns Hopkins University Applied Physics Laboratory (APL) has developed and demonstrated a multi-purpose stratospheric balloonborne gondola known as the High Altitude Research Platform (HARP). HARP provides the power, mechanical supports, thermal control, and data transmission for multiple forms of high-altitude scientific research equipment. The platform has been used for astronomy, cosmology and heliophysics experiments but can also be applied to atmospheric studies, space weather and other forms of high altitude research. HARP has executed five missions. The first was Flare Genesis from Antarctica in 1993 and the most recent was the Balloon Observation Platform for Planetary Science (BOPPS) from New Mexico in 2014. HARP will next be used to perform again the Stratospheric Terahertz Observatory mission, a mission that it first performed in 2009. The structure, composed of an aluminum framework is designed for easy transport and field assembly while providing ready access to the payload and supporting avionics. A light-weighted structure, capable of supporting Ultra-Long Duration Balloon (ULDB) flights that can last more than 100 days is available. Scientific research payloads as heavy as 600 kg (1322 pounds) and requiring up to 800 Watts electrical power can be supported. The platform comprises all subsystems required to support and operate the science payload, including both line-of-sight (LOS) and over-the-horizon (0TH) telecommunications, the latter provided by Iridium Pilot. Electrical power is produced by solar panels for multi-day missions and batteries for single-day missions. The avionics design is primarily single-string; however, use of ruggedized industrial components provides high reliability. The avionics features a Command and Control (C&C) computer and a Pointing Control System (PCS) computer housed within a common unpressurized unit. The avionics operates from ground pressure to 2 Torr and over a temperature range from —30 C to +85 C

  12. Altitude dependence of atmospheric temperature trends: Climate models versus observation

    CERN Document Server

    Douglass, D H; Singer, F

    2004-01-01

    As a consequence of greenhouse forcing, all state of the art general circulation models predict a positive temperature trend that is greater for the troposphere than the surface. This predicted positive trend increases in value with altitude until it reaches a maximum ratio with respect to the surface of as much as 1.5 to 2.0 at about 200 to 400 hPa. However, the temperature trends from several independent observational data sets show decreasing as well as mostly negative values. This disparity indicates that the three models examined here fail to account for the effects of greenhouse forcings.

  13. 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.

  14. Moessbauer studies of hemoglobin in high altitude polycythemia

    International Nuclear Information System (INIS)

    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.)

  15. Effect of altitude on protein metabolism in Bolivian children

    International Nuclear Information System (INIS)

    Protein utilization during feeding is difficult to assess by classical tracer methodology, particularly under field conditions. We propose a new approach using the measurement of tracer recovery (expired 13CO2) after the ingestion of a single oral dose of a 13C-leucine labelled milk protein. Protein will be obtained by infusing a cow with 13C-leucine. The difference between the amounts of tracer given and recovered should be an index of protein utilization. Since altitude might influence protein absorption, this non-invasive method will be used in Bolivian children, living either at 3600 m (La Paz) or at sea level. (author). 14 refs

  16. Regression of Body Density on Skinfold Thicknesses in High Altitude Natives: Decline in the Predictive Efficiency on De-Acclimatisation to Low Altitude

    Directory of Open Access Journals (Sweden)

    H. Bharadwaj

    1995-07-01

    Full Text Available Body density, stature, body weight and skinfold thickness at 11 sites were experimentally measured on two groups of high altitude natives (HAN of Ladakh. Group 1, consisting of 38 similar volunteers was studied after 4-week stay at an altitude of 3658 m and Group 2, consisting of 38 similar volunteers was studied after 4-week stay at Delhi (altitude, 200m. Although, there was a strong relationship between skinfolds, other anthropometric measurements and body density (R=0.898 at high altitude (HA, this relationship was significantly reduced at Delhi (R=0.642. Appropriate regression equations predicting body density from skinfold thicknesses, stature and body weight are given for HAN at both the locations. It is concluded that hyperhydration of the lean body and the adipose tissue may be responsible for the weakening of the multiple Rs on de-acclimatisation to low altitude.

  17. AltitudeOmics: Decreased reaction time after high altitude cognitive testing is a sensitive metric of hypoxic impairment.

    Science.gov (United States)

    Roach, Emma B; Bleiberg, Joseph; Lathan, Corinna E; Wolpert, Lawrence; Tsao, Jack W; Roach, Robert C

    2014-04-01

    Humans experiencing hypoxic conditions exhibit multiple signs of cognitive impairment, and high altitude expeditions may be undermined by abrupt degradation in mental performance. Therefore, the development of psychometric tools to quickly and accurately assess cognitive impairment is of great importance in aiding medical decision-making in the field, particularly in situations where symptoms may not be readily recognized. The present study used the Defense Automated Neurobehavioral Assessment (DANA), a ruggedized and portable neurocognitive assessment tool, to examine cognitive function in healthy human volunteers at sea level, immediately after ascending to an elevation over 5000 m, and following 16 days of acclimatization to this high altitude. The DANA battery begins with a simple reaction time test (SRT1) which is followed by a 20-min series of complex cognitive tests and ends with a second test of simple reaction time (SRT2). Tabulating the performance scores from these two tests allows the calculation of an SRT change score (dSRT=SRT1 - SRT2) that reflects the potential effect of mental effort spent during the 20-min testing session. We found that dSRT, but not direct SRT in comparison to sea-level baseline performance, is highly sensitive to acute altitude-related performance deficits and the remission of impairment following successful acclimatization. Our results suggest that dSRT is a potentially useful analytical method to enhance the sensitivity of neurocognitive assessment.This is an open access article distributed under the Creative Commons Attribution- Non Commercial License, where it is permissible to download, share and reproduce the work in any medium, provided it is properly cited. The work cannot be used commercially. PMID:24722229

  18. Does altitude moderate the impact of lithium on suicide? A spatial analysis of Austria

    Directory of Open Access Journals (Sweden)

    Marco Helbich

    2013-05-01

    Full Text Available Suicide, the tenth leading cause of death worldwide, is a complex phenomenon. Models aiming to explain the interaction of ambient variables such as socioeconomic factors, lithium content of drinking water and altitude are poorly developed. While controlling for several risk factors, this research bridges two different, but complementary research lines by investigating statistically the relationship on suicide mortality between lithium levels in drinking water in response to altitude above sea level. Besides regression models with main effects, a multiplicative interaction model between lithium and altitude has been developed providing estimates at the district-level for Austria where spatial autocorrelation was accounted for through spatial filtering. The correlation results showed a negative association between lithium levels and altitude. The regression confirmed a negative association of lithium levels and suicide mortality. Altitude was found to be positively associated with suicide mortality. On the other hand, lithium effects on suicide mortality were found to be moderated by altitude. In lower altitude regions the effect turned out to be negatively related to suicide mortality, while lithium had a positive association in high-altitude regions. These results provide evidence for the fact that the relationship between lithium, altitude and suicide rates is more complex than hitherto assumed. Further research on the effects of ambient variables such as low levels of lithium on suicide is needed and particularly the lithium-altitude interaction is worth further investigation to understand possible underlying neurochemical processes.

  19. Air to muscle O2 delivery during exercise at altitude

    DEFF Research Database (Denmark)

    Calbet, J.A.; Lundby, C.

    2009-01-01

    saturation (Sao2) 6 to 12 percentage units. Pulmonary gas exchange (PGE) is efficient at rest and, hence, the alveolar-arterial Po2 difference (Pao2-Pao2) remains close to 0 to 5mm Hg. The (Pao2-Pao2) increases with exercise duration and intensity and the level of hypoxia. During exercise in hypoxia......, diffusion limitation explains most of the additional Pao2-Pao2. With altitude, acclimatization exercise (Pao2-Pao2) is reduced, but does not reach the low values observed in high altitude natives, who possess an exceptionally high DLo2. Convective O2 transport depends on arterial O2 content (Cao2), cardiac...... output (Q), and muscle blood flow (LBF). During whole-body exercise in severe acute hypoxia and in chronic hypoxia, peak Q and LBF are blunted, contributing to the limitation of maximal oxygen uptake (Vo2max). During small-muscle exercise in hypoxia, PGE is less perturbed, Cao2 is higher, and peak Q...

  20. Reduction of Altitude Diffuser Jet Noise Using Water Injection

    Science.gov (United States)

    Allgood, Daniel C.; Saunders, Grady P.; Langford, Lester A.

    2014-01-01

    A feasibility study on the effects of injecting water into the exhaust plume of an altitude rocket diffuser for the purpose of reducing the far-field acoustic noise has been performed. Water injection design parameters such as axial placement, angle of injection, diameter of injectors, and mass flow rate of water have been systematically varied during the operation of a subscale altitude test facility. The changes in acoustic far-field noise were measured with an array of free-field microphones in order to quantify the effects of the water injection on overall sound pressure level spectra and directivity. The results showed significant reductions in noise levels were possible with optimum conditions corresponding to water injection at or just upstream of the exit plane of the diffuser. Increasing the angle and mass flow rate of water injection also showed improvements in noise reduction. However, a limit on the maximum water flow rate existed as too large of flow rate could result in un-starting the supersonic diffuser.

  1. Semianalytic Integration of High-Altitude Orbits under Lunisolar Effects

    Directory of Open Access Journals (Sweden)

    Martin Lara

    2012-01-01

    Full Text Available The long-term effect of lunisolar perturbations on high-altitude orbits is studied after a double averaging procedure that removes both the mean anomaly of the satellite and that of the moon. Lunisolar effects acting on high-altitude orbits are comparable in magnitude to the Earth’s oblateness perturbation. Hence, their accurate modeling does not allow for the usual truncation of the expansion of the third-body disturbing function up to the second degree. Using canonical perturbation theory, the averaging is carried out up to the order where second-order terms in the Earth oblateness coefficient are apparent. This truncation order forces to take into account up to the fifth degree in the expansion of the lunar disturbing function. The small values of the moon’s orbital eccentricity and inclination with respect to the ecliptic allow for some simplification. Nevertheless, as far as the averaging is carried out in closed form of the satellite’s orbit eccentricity, it is not restricted to low-eccentricity orbits.

  2. Renin and aldosterone at high altitude in man.

    Science.gov (United States)

    Keynes, R J; Smith, G W; Slater, J D; Brown, M M; Brown, S E; Payne, N N; Jowett, T P; Monge, C C

    1982-01-01

    Measurements have been made of hormonal changes relevant to salt and water balance during prolonged exposure to hypoxia to improve our understanding of the syndrome of acute mountain sickness. We have attempted to delineate the detailed inter-relationships between the renin-aldosterone and the vasopressin systems by a metabolically controlled study, involving an orthostatic stress (45 degrees head-up tilt) and an injection of a standard dose of ACTH to test adrenal responsiveness. Three Caucasian medical students underwent a 7-day equilibration at 150 m (Lima, Peru), followed by a 6-day sojourn at 4350 m (Cerro de Pasco, Peru) and a final 7 days at 150 m. Measurements were made of sodium and potassium balance, body weight and the 24-h renal excretion of vasopressin, cortisol and aldosterone 18-glucuronide. These variables showed little change, except for that of aldosterone 18-glucuronide, which fell sharply at altitude and rebounded even more sharply on return to sea level. At altitude, basal plasma levels of renin activity and aldosterone fell, and the response to orthostasis was attenuated, but the fall of plasma renin activity, as compared to plasma aldosterone, was delayed; on return to sea level this dissociation was exacerbated with the return of normal renin responsiveness lagging behind that of aldosterone. We suggest that unknown factors which dissociate the orthodox renin-aldosterone relationship, other than the activity of the angiotensin I-converting enzyme, are operative on exposure to hypoxia.

  3. Os empreendedores de vinhos de altitude do planalto catarinense

    Directory of Open Access Journals (Sweden)

    Nubia Alves de Carvalho Ferreira

    2011-09-01

    Full Text Available O objetivo desse estudo é analisar e classificar os empreendedores de vinhos de altitude do Planalto Catarinense, por meio da utilização da tipologia de Westhead; Wright (1998. Esses autores apontam três tipos - o noviço/iniciante, o serial e o de portfólio. Para tanto, analisa quais são as características empreendedoras utilizadas. Verifica ainda se o fato de possuírem experiência em outros setores colabora para a consolidação dessa nova atividade. Trata-se de uma abordagem qualitativa, sendo a pesquisa do tipo exploratória e configura-se como um estudo de caso. Os dados foram coletados por meio de pesquisa a sites, revistas, documentos e pessoas envolvidas no processo de formação e gestão dos empreendimentos em vinhos de altitude e, sobretudo, por meio de entrevistas semi-estruturadas com os empreendedores. Os resultados obtidos demonstram a tipologia portfólio, evidencia as habilidades como a característica preponderante desses empreendedores e confirmam outros trabalhos e cases pesquisados e apresentados na literatura. Ressalva-se a necessidade de novas pesquisas, em profundidade e maior número de entrevistados. 

  4. Os empreendedores de vinhos de altitude do planalto catarinense

    Directory of Open Access Journals (Sweden)

    Nubia Alves de Carvalho Ferreira

    2011-09-01

    Full Text Available O objetivo desse estudo é analisar e classificar os empreendedores de vinhos de altitude do Planalto Catarinense, por meio da utilização da tipologia de Westhead e Wright (1998. Esses autores apontam três tipos - o noviço/iniciante, o serial e o de portfólio. Para tanto, analisa quais são as características empreendedoras utilizadas. Verifica ainda se o fato de possuírem experiência em outros setores colabora para a consolidação dessa nova atividade. Trata-se de uma abordagem qualitativa, sendo a pesquisa do tipo exploratória que se configura como um estudo de caso. Os dados foram coletados por meio de pesquisa a sites, revistas, documentos e pessoas envolvidas no processo de formação e gestão dos empreendimentos em vinhos de altitude e, sobretudo, por meio de entrevistas semiestruturadas com os empreendedores. Os resultados obtidos demonstram a tipologia portfólio, evidenciam as habilidades como a característica preponderante desses empreendedores e confirmam outros trabalhos e cases pesquisados e apresentados na literatura. Ressalva-se a necessidade de novas pesquisas, em maior profundidade e número de entrevistados.

  5. Geomagnetic disturbances imprints in ground and satellite altitude observatories

    Science.gov (United States)

    Yahiat, Yasmina; Lamara, Souad; Zaourar, Naima; Hamoudi, Mohamed

    2016-04-01

    The temporal evolution of the geomagnetic field and its variations have been repeatedly studied from both ground observatories and near-earth orbiting platforms. With the advent of the space ageand the launches of geomagnetic low altitude orbits satellites, a global coverage has been achieved. Since Magsat mission, more satellites were put into orbit and some of them are still collecting data enhancing the spatial and temporal descriptions of the field. Our study uses new data gathered by the latest SWARM satellite mission launched on November, 22nd 2013. It consists of a constellation of three identical satellites carrying on board high resolution and accuracy scientific equipment. Data from this constellation will allow better understanding the multiscale behavior of the geomagnetic field. Our goal is to analyze and interpret the geomagnetic data collected by this Swarm mission, for a given period and try to separate the external disturbances from internal contributions. We consider in the study the variation of the horizontal component H, for different virtual geomagnetic observatories at the satellite altitude. The analysis of data by Swarm orbital segments shows clearly the external disturbances of the magnetic field like that occurring on 27th of August 2014. This perturbation is shown on geomagnetic indexes and is related to a coronal mass ejection (CME). These results from virtual observatories are confirmed, by the equivalent analysis using ground observatories data for the same geographic positions and same epochs. Key words: Geomagnetic field, external field, geomagnetic index, SWARM mission, virtual observatories.

  6. Renin and aldosterone at high altitude in man.

    Science.gov (United States)

    Keynes, R J; Smith, G W; Slater, J D; Brown, M M; Brown, S E; Payne, N N; Jowett, T P; Monge, C C

    1982-01-01

    Measurements have been made of hormonal changes relevant to salt and water balance during prolonged exposure to hypoxia to improve our understanding of the syndrome of acute mountain sickness. We have attempted to delineate the detailed inter-relationships between the renin-aldosterone and the vasopressin systems by a metabolically controlled study, involving an orthostatic stress (45 degrees head-up tilt) and an injection of a standard dose of ACTH to test adrenal responsiveness. Three Caucasian medical students underwent a 7-day equilibration at 150 m (Lima, Peru), followed by a 6-day sojourn at 4350 m (Cerro de Pasco, Peru) and a final 7 days at 150 m. Measurements were made of sodium and potassium balance, body weight and the 24-h renal excretion of vasopressin, cortisol and aldosterone 18-glucuronide. These variables showed little change, except for that of aldosterone 18-glucuronide, which fell sharply at altitude and rebounded even more sharply on return to sea level. At altitude, basal plasma levels of renin activity and aldosterone fell, and the response to orthostasis was attenuated, but the fall of plasma renin activity, as compared to plasma aldosterone, was delayed; on return to sea level this dissociation was exacerbated with the return of normal renin responsiveness lagging behind that of aldosterone. We suggest that unknown factors which dissociate the orthodox renin-aldosterone relationship, other than the activity of the angiotensin I-converting enzyme, are operative on exposure to hypoxia. PMID:7057120

  7. LOW ALTITUDE AIRSHIPS FOR SEAMLESS MOBILE COMMUNICATION IN AIR TRAVEL

    Directory of Open Access Journals (Sweden)

    Madhu D

    2014-11-01

    Full Text Available The Aviation Administration policy prohibits the use of mobile phones in Aircraft during transition for the reason it may harm their communication system due to Electromagnetic interference. In case the user wants to access cellular network at higher altitudes, base station access is a problem. Large number of channels are allocated to a single user moving at high speed by various Base Stations in the vicinity to service the request requiring more resources. Low Altitude Platforms (LAPs are provided in the form of Base stations in the Airships with antennas projected upwards which has direct link with the Ground Station. LAPs using LongEndurance Multi-Intelligence Vehicle (LEMVs equipped with an engine for mobility and stable positioning against rough winds are utilized. This paper proposes a system that allows the passengers to use their mobiles in Aircraft using LAPs as an intermediate system between Aircraft and Ground station. As the Aircraft is dynamic, it has to change its link frequently with the Airships, MANETs using AODV protocol is established in the prototype using NS2 to provide the service and the results are encouraging

  8. 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.

  9. Physical Body Impact After High Altitude Bail-out

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiaopeng; GUAN Huanwen; ZHUO Congshan; FENG Wenchun; ZHONG Chengwen

    2011-01-01

    In most of the emergency circumstances, the aircrew leaves the aircraft under unsatisfied conditions, such as too high relative velocity to the ambient air or Iow partial oxygen pressure. The aircrew must pass through this area as quickly as possible before opening the parachute safely, viz., free-fall. Numerical simulations are conducted in this paper to explore the major characteristics of the aircrew free-fall process by using a commercial computational fluid dynamic (CFD) software, FLUENT. Coupled with the classical pressure-altitude and temperature-altitude relations, Navier-Stokes (N-S) equations for compressible flow are solved by using finite volume method. The body velocity and the attitude are predicted with six-degree of freedom (6DOF) module. The evolution of velocities, including horizontal, vertical components and angular velocity, is obtained. It is also analyzed further according to the particle kinetic theories. It is validated that the theories can predict the process qualitatively well with a modified drag effect, which mainly stems from the velocity pressure. An empirical modification factor is proposed according to the fitting results.

  10. High altitude, a natural research laboratory for the study of cardiovascular physiology and pathophysiology.

    Science.gov (United States)

    Scherrer, Urs; Allemann, Yves; Jayet, Pierre-Yves; Rexhaj, Emrush; Sartori, Claudio

    2010-01-01

    High altitude constitutes an exciting natural laboratory for medical research. Although initially, the aim of high-altitude research was to understand the adaption of the organism to hypoxia and find treatments for altitude-related diseases, during the past decade or so, the scope of this research has broadened considerably. Two important observations led the foundation for the broadening of the scientific scope of high-altitude research. First, high-altitude pulmonary edema represents a unique model that allows studying fundamental mechanisms of pulmonary hypertension and lung edema in humans. Second, the ambient hypoxia associated with high-altitude exposure facilitates the detection of pulmonary and systemic vascular dysfunction at an early stage. Here, we will review studies that, by capitalizing on these observations, have led to the description of novel mechanisms underpinning lung edema and pulmonary hypertension and to the first direct demonstration of fetal programming of vascular dysfunction in humans.

  11. A strategy for reducing neonatal mortality at high altitude using oxygen conditioning.

    Science.gov (United States)

    West, J B

    2015-11-01

    Neonatal mortality increases with altitude. For example, in Peru the incidence of neonatal mortality in the highlands has been shown to be about double that at lower altitudes. An important factor is the low inspired PO2 of newborn babies. Typically, expectant mothers at high altitude will travel to low altitude to have their babies if possible, but often this is not feasible because of economic factors. The procedure described here raises the oxygen concentration in the air of rooms where neonates are being housed and, in effect, this means that both the mother and baby are at a much lower altitude. Oxygen conditioning is similar to air conditioning except that the oxygen concentration of the air is increased rather than the temperature being reduced. The procedure is now used at high altitude in many hotels, dormitories and telescope facilities, and has been shown to be feasible and effective.

  12. A strategy for reducing neonatal mortality at high altitude using oxygen conditioning.

    Science.gov (United States)

    West, J B

    2015-11-01

    Neonatal mortality increases with altitude. For example, in Peru the incidence of neonatal mortality in the highlands has been shown to be about double that at lower altitudes. An important factor is the low inspired PO2 of newborn babies. Typically, expectant mothers at high altitude will travel to low altitude to have their babies if possible, but often this is not feasible because of economic factors. The procedure described here raises the oxygen concentration in the air of rooms where neonates are being housed and, in effect, this means that both the mother and baby are at a much lower altitude. Oxygen conditioning is similar to air conditioning except that the oxygen concentration of the air is increased rather than the temperature being reduced. The procedure is now used at high altitude in many hotels, dormitories and telescope facilities, and has been shown to be feasible and effective. PMID:26426252

  13. Genetic Differentiation of Pinus koraiensis under Different Altitude Conditions in Changbai Mountain

    Institute of Scientific and Technical Information of China (English)

    FENGFujuan

    2004-01-01

    The genetic differentiation of Korean pine (Pinus koraiensis) in different altitudes in Changbai Mountain was analyzed by ISSR technique, and it was found that the level of genetic diversity of Korean pine reduces along with altitude increasing in Changbai Mountain. The variation of Korean pine is mainly from intra-population and there is a positive relativity between genetic distance and vertical geographic distance of Korean pine in different altitudes. The genetic coherence shows that altitude has less insulation to Korean pine. Therefore, it is deduced that the terrain formation of vertical distribution of Korean pine is a result of diffusion from lower altitude to higher altitude in the course of enlarging its adaptability.

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

    OpenAIRE

    Chun Guo; Jianfeng Xu; Mingnian Wang; Tao Yan; Lu Yang; Zhitao Sun

    2015-01-01

    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. ...

  15. AKR-like emissions observed at low altitude by the DEMETER satellite

    OpenAIRE

    Parrot, Michel; Berthelier, Jean-Jacques

    2012-01-01

    International audience This paper reports observations of Auroral Kilometric Radiation (AKR) by the low altitude satellite DEMETER (700 km) during the super magnetic storm of November 2004. AKR is generated along auroral field lines at altitudes above ~ 3000 km and escapes from the Earth so that most observations have been made close to the source regions or at large distances from the Earth. However, EM waves with AKR-like frequency spectra detected by the low altitude EXOS-C satellite we...

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

    OpenAIRE

    Sikri G; Bhattacharya A

    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-altitude ill...

  17. The comparison of physical fitness in secondary male students in altitude and coastal areas

    OpenAIRE

    ZAHIBI, Esmaeil; ALAVI, Seyed Hossein

    2015-01-01

    The aim of this research is the comparison of physical fitness in secondary male students in altitude and coastal areas and difference between the physical fitness on based AAHPERD test. The samples consist of 450 subjects of 1017 subjects in altitude (Shahrekord) and coastal area (Mahmood Abad) in Iran in years of 2013 which were selected cluster- randomly sampling by Morgan Table. We investigated the effect of high altitude on the tests of physical fitness resident students near sea level (...

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

    OpenAIRE

    Emma eDespland

    2014-01-01

    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, be...

  19. Metabolic insight into mechanisms of high-altitude adaptation in Tibetans

    OpenAIRE

    Ge, Ri-Li; Simonson, Tatum S.; Cooksey, Robert C.; Tanna, Uran; Qin, Ga; Huff, Chad D.; WITHERSPOON, DAVID J.; Xing, Jinchuan; Zhengzhong, Bai; Prchal, Josef T.; Jorde, Lynn B.; McClain, Donald A.

    2012-01-01

    Recent studies have identified genes involved in high-altitude adaptation in Tibetans. Genetic variants/haplotypes within regions containing three of these genes (EPAS1, EGLN1, and PPARA) are associated with relatively decreased hemoglobin levels observed in Tibetans at high altitude, providing corroborative evidence for genetic adaptation to this extreme environment. The mechanisms that afford adaptation to high-altitude hypoxia, however, remain unclear. Considering the strong metabolic dema...

  20. The Legality of Wind and Altitude Assisted Performances in the Sprints

    CERN Document Server

    Mureika, J R

    2001-01-01

    Based on a mathematical simulation which reproduces accurate split and velocity profiles for the 100 and 200 metre sprints, the magnitudes of altitude and mixed wind/altitude-assisted performances as compared to their sea-level equivalents are presented. It is shown that altitude-assisted times for the 200 metre are significantly higher than for the 100 metre, suggesting that the ``legality'' of such marks perhaps be reconsidered.

  1. The body weight loss during acute exposure to high-altitude hypoxia in sea level residents.

    Science.gov (United States)

    Ge, Ri-Li; Wood, Helen; Yang, Hui-Huang; Liu, Yi-Ning; Wang, Xiu-Juan; Babb, Tony

    2010-12-25

    Weight loss is frequently observed after acute exposure to high altitude. However, the magnitude and rate of weight loss during acute exposure to high altitude has not been clarified in a controlled prospective study. The present study was performed to evaluate weight loss at high altitude. A group of 120 male subjects [aged (32±6) years] who worked on the construction of the Golmud-Lhasa Railway at Kunlun Mountain (altitude of 4 678 m) served as volunteer subjects for this study. Eighty-five workers normally resided at sea level (sea level group) and 35 normally resided at an altitude of 2 200 m (moderate altitude group). Body weight, body mass index (BMI), and waist circumference were measured in all subjects after a 7-day stay at Golmud (altitude of 2 800 m, baseline measurements). Measurements were repeated after 33-day working on Kunlun Mountain. In order to examine the daily rate of weight loss at high altitude, body weight was measured in 20 subjects from the sea level group (sea level subset group) each morning before breakfast for 33 d at Kunlun Mountain. According to guidelines established by the Lake Louise acute mountain sickness (AMS) consensus report, each subject completed an AMS self-report questionnaire two days after arriving at Kunlun Mountain. After 33-day stay at an altitude of 4 678 m, the average weight loss for the sea level group was 10.4% (range 6.5% to 29%), while the average for the moderate altitude group was 2.2% (-2% to 9.1%). The degree of weight loss (Δ weight loss) after a 33-day stay at an altitude of 4 678 m was significantly correlated with baseline body weight in the sea level group (r=0.677, P0.05). In the sea level subset group, a significant weight loss was observed within 20 d, but the weight remained stable thereafter. AMS-score at high altitude was significantly higher in the sea level group (4.69±2.48) than that in the moderate altitude group (2.97±1.38), and was significantly correlated with baseline body weight

  2. 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.

  3. 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.

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

    Science.gov (United States)

    Hu, Sheng Li; Xiong, Wei; Dai, Zhi Qiang; Zhao, Heng Li; Feng, Hua

    2016-01-01

    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 500m altitude, 3650m altitude, 3day, 1, and 3 month post arriving at the base camp (4400m), and 1 month after coming back to the 500m 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 (4400m). 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. PMID:26731740

  5. Different responses of different altitudes surrounding Taklimankan Desert to global climate change

    Science.gov (United States)

    Chongyi, E.; Yong, Wang; Taibao, Yang; Jiankang, Han; Hongchang, Hu; Fengmei, Yang

    2009-02-01

    Chongce Ice Cap (35°14'N, 81°07'E), located in the south margin of Taklimakan Desert, West Kunlun Mts. of China was sampled by coring in 1992, and this provides us with climate proxy of high altitudes (6,530 m). Through analyzing the weather observation stations surrounding Taklimakan Desert, the climate record of Hotan station was chosen to be the representative of low altitudes. Wavelet analysis were used to investigate the climatic variations of patterns, cycles and frequencies of different altitudes from 1954 to 1992, and different responses of different altitude surrounding Taklimakan Desert to global warming were recorded: (1) coherent decline of snow accumulation rate and dust deposition of high altitude recorded in Chongce ice core; (2) coherent increase of summer half-year precipitation and SAT of Hotan; (3) consistent variation tendency between dust deposit recorded in Chongce ice core and Hotan spring sandstorm days; (4) opposite variation tendency between Hotan precipitation and Chongce ice core snow accumulation rate and consistent cycles in general. By analyzing the mechanism of different responses, the predominant factors were determined of different altitudes: (1) at the low altitude, the vapor supply is predominant, and more vapor supplying means more precipitation; (2) at the high altitude, probably the population of dust aerosols which act as cloud ice nuclei in high altitude takes advantage over the vapor supply to affect the precipitation, and so the dust aerosol population reducing results in the wet deposition being reduced, thus the dust aerosol is the predominant factor.

  6. What high altitude observations tell us about the auroral acceleration: A Cluster/DMSP conjunction

    OpenAIRE

    A. Vaivads; ANDRE, M; S. Buchert; Eriksson, A.; Olsson, A; Wahlund, J. E.; Janhunen, P.; Marklund, G.; Kistler, L. M.; Mouikis, S.; Winningham, D.; Fazakerley, A.N.; Newell, P.

    2003-01-01

    Magnetic conjugate observations by Cluster and DMSP F14 satellites are used to study the field lines of auroral arc. Cluster is well above the acceleration region and observes upward keV ion beams and bipolar electric structures. The integrated potential at Cluster altitudes shows a dip that is consistent with the keV electron acceleration energy at low altitude. The earthward Poynting flux at Cluster altitudes is comparable to the electron energy flux at low altitudes. Thus, for this event t...

  7. Thermoelectric Energy Conversion Technology for High-Altitude Airships

    Science.gov (United States)

    Choi, Sang H.; Elliott, James R.; King, Glen C.; Park, Yeonjoon; Kim, Jae-Woo; Chu, Sang-Hyon

    2011-01-01

    The High Altitude Airship (HAA) has various application potential and mission scenarios that require onboard energy harvesting and power distribution systems. The power technology for HAA maneuverability and mission-oriented applications must come from its surroundings, e.g. solar power. The energy harvesting system considered for HAA is based on the advanced thermoelectric (ATE) materials being developed at NASA Langley Research Center. The materials selected for ATE are silicon germanium (SiGe) and bismuth telluride (Bi2Te3), in multiple layers. The layered structure of the advanced TE materials is specifically engineered to provide maximum efficiency for the corresponding range of operational temperatures. For three layers of the advanced TE materials that operate at high, medium, and low temperatures, correspondingly in a tandem mode, the cascaded efficiency is estimated to be greater than 60 percent.

  8. Multivariable control altitude demonstration on the F100 turbofan engine

    Science.gov (United States)

    Lehtinen, B.; Dehoff, R. L.; Hackney, R. D.

    1979-01-01

    The control system designed under the Multivariable Control Synthesis (MVCS) program for the F100 turbofan engine is described. The MVCS program, applied the linear quadratic regulator (LQR) synthesis methods in the design of a multivariable engine control system to obtain enhanced performance from cross-coupled controls, maximum use of engine variable geometry, and a systematic design procedure that can be applied efficiently to new engine systems. Basic components of the control system, a reference value generator for deriving a desired equilibrium state and an approximate control vector, a transition model to produce compatible reference point trajectories during gross transients, gain schedules for producing feedback terms appropriate to the flight condition, and integral switching logic to produce acceptable steady-state performance without engine operating limit exceedance are described and the details of the F100 implementation presented. The engine altitude test phase of the MVCS program, and engine responses in a variety of test operating points and power transitions are presented.

  9. Radiation Physics for Space and High Altitude Air Travel

    Science.gov (United States)

    Cucinotta, F. A.; Wilson, J. W.; Goldhagen, P.; Saganti, P.; Shavers, M. R.; McKay, Gordon A. (Technical Monitor)

    2000-01-01

    Galactic cosmic rays (GCR) are of extra-solar origin consisting of high-energy hydrogen, helium, and heavy ions. The GCR are modified by physical processes as they traverse through the solar system, spacecraft shielding, atmospheres, and tissues producing copious amounts of secondary radiation including fragmentation products, neutrons, mesons, and muons. We discuss physical models and measurements relevant for estimating biological risks in space and high-altitude air travel. Ambient and internal spacecraft computational models for the International Space Station and a Mars mission are discussed. Risk assessment is traditionally based on linear addition of components. We discuss alternative models that include stochastic treatments of columnar damage by heavy ion tracks and multi-cellular damage following nuclear fragmentation in tissue.

  10. 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.

  11. Development of High Altitude UAV Weather Radars for Hurricane Research

    Science.gov (United States)

    Heymsfield, Gerald; Li, Li-Hua

    2005-01-01

    A proposed effort within NASA called (ASHE) over the past few years was aimed at studying the genesis of tropical disturbances off the east coast of Africa. This effort was focused on using an instrumented Global Hawk UAV with high altitude (%Ok ft) and long duration (30 h) capability. While the Global Hawk availability remains uncertain, development of two relevant instruments, a Doppler radar (URAD - UAV Radar) and a backscatter lidar (CPL-UAV - Cloud Physics Lidar), are in progress. The radar to be discussed here is based on two previous high-altitude, autonomously operating radars on the NASA ER-2 aircraft, the ER-2 Doppler Radar (EDOP) at X-band (9.6 GHz), and the Cloud Radar System (CRS) at W- band (94 GHz). The nadir-pointing EDOP and CRS radars profile vertical reflectivity structure and vertical Doppler winds in precipitation and clouds, respectively. EDOP has flown in all of the CAMEX flight series to study hurricanes over storms such as Hurricanes Bonnie, Humberto, Georges, Erin, and TS Chantal. These radars were developed at Goddard over the last decade and have been used for satellite algorithm development and validation (TRMM and Cloudsat), and for hurricane and convective storm research. We describe here the development of URAD that will measure wind and reflectivity in hurricanes and other weather systems from a top down, high-altitude view. URAD for the Global Hawk consists of two subsystems both of which are at X-band (9.3-9.6 GHz) and Doppler: a nadir fixed-beam Doppler radar for vertical motion and precipitation measurement, and a Conical scanning radar for horizontal winds in cloud and at the surface, and precipitation structure. These radars are being designed with size, weight, and power consumption suitable for the Global Hawk and other UAV's. The nadir radar uses a magnetron transmitter and the scanning radar uses a TWT transmitter. With conical scanning of the radar at a 35" incidence angle over an ocean surface in the absence of

  12. Altitude training and its influence on physical endurance in swimmers.

    Science.gov (United States)

    Strzała, Marek; Ostrowski, Andrzej; Szyguła, Zbigniew

    2011-06-01

    It is possible to plan an altitude training (AT) period in such a way that the enhanced physical endurance obtained as a result of adaptation to hypoxia will appear and can be used to improve performance in competition. Yet finding rationales for usage of AT in highly trained swimmers is problematic. In practice AT, in its various forms, is still controversial, and an objective review of research concentrating on the advantages and disadvantages of AT has been presented in several scientific publications, including in no small part the observations of swimmers. The aim of this article is to review the various methods and present both the advantageous and unfavourable physiological changes that occur in athletes as a result of AT. Moreover, AT results in the sport of swimming have been collected. They include an approach towards primary models of altitude/hypoxic training: live high + train high, live high + train low, live low + train high, as well as subsequent methods: Intermittent Hypoxic Exposure (IHE) and Intermittent Hypoxic Training (IHT). Apnoea training, which is descended from freediving, is also mentioned, and which can be used with, or as a substitute for, the well-known IHE or IHT methods. In conclusion, swimmers who train using hypoxia may be among the best-trained athletes, and that even a slight improvement in physical endurance might result in the shortening of a swimming time in a given competition, and the achievement of a personal best, which is hard to obtain by normal training methods, when the personal results of the swimmer have reached a plateau. PMID:23486564

  13. Analytical estimate for low-altitude ENA emissivity

    Science.gov (United States)

    Goldstein, J.; Bisikalo, D. V.; Shematovich, V. I.; Gérard, J.-C.; Søraas, F.; McComas, D. J.; Valek, P. W.; LLera, K.; Redfern, J.

    2016-02-01

    We formulate the first analytical model for energetic neutral atom (ENA) emissivity that partially corrects for the global viewing geometry dependence of low-altitude emissions (LAEs) observed by Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS). The emissivity correction requires the pitch angle distribution (PAD) and geophysical location of low-altitude ENAs. To estimate PAD, we create an energy-dependent analytical model, based on a Monte Carlo simulation. We account for energy binning by integrating model PAD over each energy bin. We account for finite angular pixels by computing emissivity as an integral over the pitch angle range sampled by the pixel. We investigate location uncertainty in TWINS pixels by performing nine variations of the emissivity calculation. Using TWINS 2 ENA imaging data from 1131 to 1145 UT on 6 April 2010, we derive emissivity-corrected ion fluxes for two angular pixel sizes: 4° and 1°. To evaluate the method, we compare TWINS-derived ion fluxes to simultaneous in situ data from the National Oceanic and Atmospheric Administration (NOAA) 17 satellite. The TWINS-NOAA agreement for emissivity-corrected flux is improved by up to a factor of 7, compared to uncorrected flux. The highest 1° pixel fluxes are a factor of 2 higher than for 4° pixels, consistent with pixel-derived fluxes that are artificially low because subpixel structures are smoothed out, and indicating a possible slight advantage to oversampling the instrument-measured LAE signal. Both TWINS and NOAA ion fluxes decrease westward of 2000 magnetic local time. The TWINS-NOAA comparison indicates that the global ion precipitation oval comprises multiple smaller-scale (3-5° of latitude) structures.

  14. Viticultura tropical a gran altitud. Condiciones y expresiones del terroir

    Directory of Open Access Journals (Sweden)

    Marco Quijano Rico

    2009-10-01

    Full Text Available Nuestro proyecto se inició en 1982 en la Loma de Puntalarga, entre 2500 y2600 metros de altitud, a 5,78 ºN y 72,98 ºW, en la cordillera oriental de los Andes. Las variedades más utilizadas actualmente son Pinot noir, Riesling y cruzamientos de Riesling x Silvaner. Desde 1984 se realizan trabajos de investigación sobre temas pertinentes. La baja latitud, la elevada altitud, el volumen de precipitación relativamente modesto y la transparencia del cielo, determinan el flujo de radiación solar incidente y su composición espectral, así como la amplitud del cambio de temperatura entre el día y la noche y las bajas temperaturas nocturnas, que son los rasgos del clima frío imperante en la región. El comportamiento de las cepas y las características del vino indican que las condiciones climáticas locales, pueden considerarse térmicamente equivalentesa las de ciertos territorios tradicionales renombrados. La coexistencia durante el año de todos los estadios de vegetación de la vid y la producción de vendimias con buen contenido de azúcar y niveles suficientes de acidez, hace posible la elaboración de vinos de calidad sobresaliente, de modo secuencial y continuo.En los viñedos del proyecto, las condiciones climáticas anuales son equivalentesa las otoñales, de maduración de las uvas en regiones septentrionales y australes. Al mismo tiempo, el flujo de radiación solar no sufre cambios notables y es rico en las longitudes de onda del ultravioleta B. Los dos factores pueden marcar las características de las uvas, haciendo parte así del efecto terroir.

  15. [Human life at high altitudes: myths and realities].

    Science.gov (United States)

    Vargas, E; Villena, M

    1989-01-01

    Life at high altitude presents very interesting biological and medical aspects. For countries such as the Andeans, it also has socio-economical implications. The most important towns of Bolivia are situated between 3,000 and 4,850 m. It's to say that a great percentage of the population is permanently staying there. Moreover owing to the improvement of the roads and transport, an extensive migration (professional life, business, tourism, sport) developed some years ago. At 3,000 to 4,850 m, an oxygen arterial pressure (PaO2) between 40 and 70 mm Hg is resulting from the environmental hypoxia. The adaptation to hypoxia takes place in two phases: --that incomplete, observed at short time in people who recently arrived, --that at very long time, observed in the native. The rapid arrival at more than 3,000 m, exposes the traveller to an hypoxic ventilatory stimulus which produces a hyperventilation response to increased PaO2. This hyperventilation brings out a decreasing of carbon dioxide arterial pressure (PaCO2) and alkalosis of the blood. This respiratory alkalosis seems to be responsible for most troubles which are present in the Acute Mountain Sickness linked to the CO2 role in cerebral blood circulation. At the same time but more slowly the classical high altitude polycythemia develops which permits compensate partially the hypoxic effect in 3 to 4 weeks. In the native the adaptation implies physiological variations of some parameters concerning the individual development. The principal studies showed that the native present a notable hyposensitivity to hypoxia and also to the stimulus CO2-H+. The Chronic Mountain Sickness patients have a less sensitivity to the same stimuli than the natives. PMID:2699275

  16. Computer vision techniques for rotorcraft low altitude flight

    Science.gov (United States)

    Sridhar, Banavar

    1990-01-01

    Rotorcraft operating in high-threat environments fly close to the earth's surface to utilize surrounding terrain, vegetation, or manmade objects to minimize the risk of being detected by an enemy. Increasing levels of concealment are achieved by adopting different tactics during low-altitude flight. Rotorcraft employ three tactics during low-altitude flight: low-level, contour, and nap-of-the-earth (NOE). The key feature distinguishing the NOE mode from the other two modes is that the whole rotorcraft, including the main rotor, is below tree-top whenever possible. This leads to the use of lateral maneuvers for avoiding obstacles, which in fact constitutes the means for concealment. The piloting of the rotorcraft is at best a very demanding task and the pilot will need help from onboard automation tools in order to devote more time to mission-related activities. The development of an automation tool which has the potential to detect obstacles in the rotorcraft flight path, warn the crew, and interact with the guidance system to avoid detected obstacles, presents challenging problems. Research is described which applies techniques from computer vision to automation of rotorcraft navigtion. The effort emphasizes the development of a methodology for detecting the ranges to obstacles in the region of interest based on the maximum utilization of passive sensors. The range map derived from the obstacle-detection approach can be used as obstacle data for the obstacle avoidance in an automatic guidance system and as advisory display to the pilot. The lack of suitable flight imagery data presents a problem in the verification of concepts for obstacle detection. This problem is being addressed by the development of an adequate flight database and by preprocessing of currently available flight imagery. The presentation concludes with some comments on future work and how research in this area relates to the guidance of other autonomous vehicles.

  17. 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

  18. Longterm monitoring of ambient dose equivalent rates at aviation altitudes

    Energy Technology Data Exchange (ETDEWEB)

    Heber, B.; Burmeister, S.; Moeller, T.; Scharrenberg, E. [Institut fuer Experimentelle und Angewandte Physik, Christian-Albrechts-Universitaet zu Kiel, Kiel (Germany); Briese, J. [Deutsche Lufthansa AG, Frankfurt am Main (Germany); Burda, O.; Klages, T.; Langner, F.; Marquardt, J.; Wissmann, F. [Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig Germany (Germany); Matthiae, D.; Reitz, G. [German Aerospace Center, Institute of Aerospace Medicine, Linder Hoehe, 51147 Koeln (Germany)

    2012-07-01

    The complex radiation field at flight altitudes results mainly from the interaction of energetic charged particles with atmospheric molecules and atoms and consists of secondary neutrons, protons, gamma rays, electrons, positrons and muons. Due to the continuous interactions of primary and secondary particles within the atmosphere, the intensity of each component depends on the height. Since the Earth's magnetic field acts as rigidity filter for the charged primary particles, the flux of the primary particles into the atmosphere and the resulting intensity of secondary particles depend on the geomagnetic latitude being highest over the geomagnetic poles. The main primary component consists of Galactic Cosmic Rays (GCRs), mainly protons and alpha particles, whose flux is modulated in the heliosphere. Beside this slowly varying galactic component, solar energetic particle events may temporarily increase the intensity of this radiation field. In the frame of the Radiation Monitoring on Board Aircraft (RAMONA) collaboration, three NAVIgation and DOSimetry (NAVIDOS) systems were installed in 2008 and 2009 on board of three Lufthansa Airbus A340 aircraft. They have been maintained since then by the consortium. Two of the NAVIDOS units rely on the DOSimetry TELescopes (DOSTELs), one is based on a LIULIN detector. This unique setup is ideally suited to investigate variations in the radiation field at different flight altitudes and geomagnetic positions and has been used to measure the radiation exposure during the recent extended solar minimum and thereafter. With increasing solar activity in 2010 the measured dose rates have been decreasing. Since these variations depend on the location of the aircraft, a detailed data analysis is required and presented.

  19. Effect of simulated high-altitude hypoxia on Porphyromonas gingivalis

    Directory of Open Access Journals (Sweden)

    Jing-jing HUANG

    2012-04-01

    Full Text Available Objective To investigate the effects of simulated high-altitude hypoxia on the detection rate and endotoxin level of Porphyromonas gingivalis (Pg of subgingival bacterial plagues in rabbit periodontitis models. Methods Forty male rabbits were randomly divided into four groups, namely, normoxia control group (group A1, normoxia experimental group (group A2, hypoxia control group (group B1, and hypoxia experimental group (group B2. Each group included 10 rabbits. Periodontitis models was established in groups A2 and B2 combined by ligating both lower central incisors with steel ligature and feeding periodontitis diets, and then the animals were housed in a hypoxia chamber (simulating 5000m altitude, 23h per day. Groups A1 and A2 were raised normal diet in normoxia environment. After eight weeks, the rabbit periodontitis model was evaluated by observing radiographic features of the X-ray films and histopathologic changes under a light microscope. Subgingival plague sample from periodontal pockets on both lower central incisors were collected for isolation, culture and identification of Pg, and for detection of the endotoxin level. Results The histopathologic observation and X-ray examination results showed that the periodontitis of rabbits in group B2 was significantly more severe than that in group A2. The detection rates of Pg in group A1, A2, B1 and B2 was 0%, 50%, 55% and 95% (P < 0.05. Pg detection rate and endotoxin level were higher in group B2 (95%, 0.46±0.04EU/ml than in group A2 (50%, 0.38±0.02EU/ml, P < 0.05. Conclusions The process speed and damage degree of periodontitis in hypoxic environment is higher than that in normoxic environment. Moreover, the hypoxic environment is more suitable in the colonization of Pg with higher endotoxin level in subgingival plague.

  20. Pre-Altitude Serum Ferritin Levels and Daily Oral Iron Supplement Dose Mediate Iron Parameter and Hemoglobin Mass Responses to Altitude Exposure.

    Directory of Open Access Journals (Sweden)

    Andrew D Govus

    Full Text Available To investigate the influence of daily oral iron supplementation on changes in hemoglobin mass (Hbmass and iron parameters after 2-4 weeks of moderate altitude exposure.Hematological data collected from 178 athletes (98 males, 80 females exposed to moderate altitude (1,350-3,000 m were analysed using linear regression to determine how altitude exposure combined with oral iron supplementation influenced Hbmass, total iron incorporation (TII and blood iron parameters [ferritin and transferrin saturation (TSAT].Altitude exposure (mean ± s: 21 ± 3 days increased Hbmass by 1.1% [-0.4, 2.6], 3.3% [1.7, 4.8], and 4.0% [2.0, 6.1] from pre-altitude levels in athletes who ingested nil, 105 mg and 210 mg respectively, of oral iron supplement daily. Serum ferritin levels decreased by -33.2% [-46.9, -15.9] and 13.8% [-32.2, 9.7] from pre-altitude levels in athletes who supplemented with nil and 105 mg of oral iron supplement daily, but increased by 36.8% [1.3, 84.8] in athletes supplemented with 210 mg of oral iron daily. Finally, athletes who ingested either 105 mg or 210 mg of oral iron supplement daily had a greater TII compared with non-supplemented athletes (0 versus 105 mg: effect size (d = -1.88 [-2.56, -1.17]; 0 versus 210 mg: effect size (d = -2.87 [-3.88, -1.66].Oral iron supplementation during 2-4 weeks of moderate altitude exposure may enhance Hbmass production and assist the maintenance of iron balance in some athletes with low pre-altitude iron stores.

  1. Acúmulo de nutrientes em frutos de cafeeiro em duas altitudes de cultivo: micronutrientes Nutrient accumulation in coffee fruits at two at two plantation altitudes: micronutrients

    Directory of Open Access Journals (Sweden)

    Bruno Galvêas Laviola

    2007-12-01

    Full Text Available Dado à importância de se conhecer a exportação de micronutrientes pelos frutos, bem como, as épocas em que são mais demandados pelo cafeeiro, estudou-se o acúmulo de B, Cu, Fe, Mn e Zn em frutos de Coffea arabica L da antese à maturação, em lavouras estabelecidas em duas altitudes. Estudou-se também a variação no teor desses elementos. Estudou-se o acúmulo de B, Cu, Fe, Mn e Zn em frutos de cafeeiro arábico da antese à maturação em duas altitudes, bem como a variação na concentração dos elementos em folhas dos ramos produtivos. O experimento foi constituído da variedade de cafeeiro (Coffea arabica L. Catuaí IAC 44 cultivada a 720 e 950 m de altitude, no município de Martins Soares-MG. O delineamento experimental foi inteiramente ao acaso, com três repetições, usando um esquema de parcela subdividida no tempo. O aumento da altitude influenciou o ciclo reprodutivo do cafeeiro, demandando maior tempo para formação dos frutos. O consumo de nutrientes pelos frutos, assim como o enchimento de grãos, foi mais crítico em condições de menor altitude, já que a planta necessitou completar esses processos em menor espaço de tempo. No estádio de expansão rápida, a percentagem de acúmulo de micronutrientes foi maior na altitude de 720 m, comparada à de 950 m. De modo geral, a altitude influenciou a variação das concentrações foliares de nutrientes, apesar de não se ter observado resposta-padrão da concentração foliar ao aumento da altitude. Conclui-se que a altitude teve influência na extensão do ciclo, bem como no acúmulo de micronutrientes em frutos e na variação, das concentrações foliares destes elementos em folhas de cafeeiro.In view of the importance of knowing fruit micronutrients export from the soil, and the season in which its coffee-plant demand is higher, the accumulation of B, Cu, Fe, Mn and Zn in fruits as well as the variation in the leaf content of the elements in productive branches of

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

    Science.gov (United States)

    Guo, Chun; Xu, Jianfeng; Wang, Mingnian; Yan, Tao; Yang, Lu; Sun, Zhitao

    2016-01-01

    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. PMID:26703703

  3. Discussion of the target-missile control scheme with supersonic speed at minimum altitude

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    An antiship missile with supersonic speed at minimum altitude is an effective weapon to break through a defense line. The former Soviet Union was a leader in this field since it had developed several kinds of antiship missiles which obtained supersonic speed at minimum altitudes. To counter this kind of missile,many countries have been developing corresponding antimissiles. For the purpose of verifing the antimissile missile's effectiveness in intercepting antiship missiles, a target-missile is needed. A target-missle is cheaper and can imitate the main characteristics of antiship missiles with supersonic speed at minimum altitude. In this paper, the control scheme of a target missile flying with supersonic speed at minimum altitude is studied. To counter the problem of hedgehopping over the sea, a control scheme utilizing a SINS + altimeter was proposed.In this scheme, both the quick response ability of altitude control and the anti-jamming problem were considered. A simulation experiment shows that when an integrated altitude control system is used, the anti-disturbance ability of the integrated altitude is good and the response speed of altitude control system can be dramatically improved.

  4. Metal-induced shifts in benthic macroinvertebrate community composition in Andean high altitude streams

    NARCIS (Netherlands)

    R.A. Loayza-Muro; R. Elías-Letts; J.K. Marticorena-Ruíz; E.J. Palomino; J.F. Duivenvoorden; M.H.S. Kraak; W. Admiraal

    2010-01-01

    High altitude creates unique challenging conditions to biota that limit the diversity of benthic communities. Because environmental pollution may add further stress to life at high altitude, the present study explored the effect of metal pollution on the macroinvertebrate community composition in An

  5. 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 grounds

  6. Considerations on safety and treatment of patients with chronic heart failure at high altitude.

    Science.gov (United States)

    Agostoni, Piergiuseppe

    2013-06-01

    Prognosis and quality of life of chronic heart failure (HF) patients have greatly improved over the last decade. Consequently, many patients are willing to spend leisure time at altitude, usually spending time at altitude is likely different from optimal treatment at sea level, particularly as regards β-blockers. Carvedilol, a β1-β2-α-blocker, reduces the hypoxic ventilatory response through a reduction of the chemoreflex response, and it reduces alveolar-capillary gas diffusion, which is under control by β2-receptors. These actions are not shared by selective β1-blockers such as bisoprolol and nebivolol, which should be preferred for treatment of HF patients willing to spend time at altitude. In conclusion, spending time at altitude (<3500 m) is safe for HF patients, provided that subjects are free of co-morbidities that may directly interfere with the adaptation to altitude. However, HF patients experience a reduction of exercise capacity in proportion to HF severity and altitude. Finally, HF patients should undergo a specific "altitude-tailored treatment" to avoid pharmacological interference with altitude adaptation mechanisms. PMID:23795728

  7. 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,

  8. 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.

  9. From Doktor Kurowski's Schneegrenze to our modern glacier equilibrium line altitude (ELA

    Directory of Open Access Journals (Sweden)

    R. J. Braithwaite

    2015-06-01

    Full Text Available Translated into modern terminology, Kurowski suggested in 1891 that the equilibrium line altitude (ELA of a glacier is equal to the mean altitude of the glacier when the whole glacier is in balance between accumulation and ablation. Kurowski's method has been widely misunderstood, partly due to inappropriate use of statistical terminology by later workers, and has been little tested except by Braithwaite and Müller in a 1980 paper (for 32 glaciers. I now compare Kurowski's mean altitude with balanced-budget ELA calculated for 103 modern glaciers with measured surface mass balance data. Kurowski's mean altitude is significantly higher (at 95% level than balanced-budget ELA for 19 outlet and 42 valley glaciers, but not significantly higher for 34 mountain glaciers. The error in Kurowski mean altitude as a predictor of balanced-budget ELA might be due to generally lower balance gradients in accumulation area compared with ablation areas for many glaciers, as suggested by several workers, but some glaciers have higher gradients, presumably due to precipitation increase with altitude. The relatively close agreement between balanced-budget ELA and mean altitude for mountain glaciers (mean error −8 m with standard deviation 59 m may reflect smaller altitude ranges for these glaciers such that there is less room for effects of different balance gradients to manifest themselves.

  10. From Doktor Kurowski's Schneegrenze to our modern glacier equilibrium line altitude (ELA)

    Science.gov (United States)

    Braithwaite, R. J.

    2015-11-01

    Translated into modern terminology, Kurowski suggested in 1891 that the equilibrium line altitude (ELA) of a glacier is equal to the mean altitude of the glacier when the whole glacier is in balance between accumulation and ablation. Kurowski's method has been widely misunderstood, partly due to inappropriate use of statistical terminology by later workers, and has only been tested by Braithwaite and Müller in a 1980 paper (for 32 glaciers). I now compare Kurowski's mean altitude with balanced-budget ELA calculated for 103 present-day glaciers with measured surface mass-balance data. Kurowski's mean altitude is significantly higher (at 95 % level) than balanced-budget ELA for 19 outlet and 42 valley glaciers, but not significantly higher for 34 mountain glaciers. The error in Kurowski mean altitude as a predictor of balanced-budget ELA might be due to generally lower balance gradients in accumulation areas compared with ablation areas for many glaciers, as suggested by several workers, but some glaciers have higher gradients, presumably due to precipitation increase with altitude. The relatively close agreement between balanced-budget ELA and mean altitude for mountain glaciers (mean error - 8 m with standard deviation 59 m) may reflect smaller altitude ranges for these glaciers such that there is less room for effects of different balance gradients to manifest themselves.

  11. 14 CFR 91.215 - ATC transponder and altitude reporting equipment and use.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false ATC transponder and altitude reporting... RULES Equipment, Instrument, and Certificate Requirements § 91.215 ATC transponder and altitude... under part 121 or 135 of this chapter, ATC transponder equipment installed must meet the performance...

  12. Cosmic Rays with Portable Geiger Counters: From Sea Level to Airplane Cruise Altitudes

    Science.gov (United States)

    Blanco, Francesco; La Rocca, Paola; Riggi, Francesco

    2009-01-01

    Cosmic ray count rates with a set of portable Geiger counters were measured at different altitudes on the way to a mountain top and aboard an aircraft, between sea level and cruise altitude. Basic measurements may constitute an educational activity even with high school teams. For the understanding of the results obtained, simulations of extensive…

  13. The impact of altitude on early outcome following the Fontan operation

    Directory of Open Access Journals (Sweden)

    Nashef Samer AM

    2006-10-01

    Full Text Available Abstract Background The success of a Fontan circulation depends on several factors including low pulmonary vascular resistance. Pulmonary vascular resistance rises in response to hypoxia. Hypoxia is associated with altitude. Therefore, we wondered whether altitude is a risk factor for early failure after the Fontan operation. The aim was to test this hypothesis. Methods Data were obtained from all published series of 'total cavopulmonary' Fontan operations since 1990. The early failure rate from each series and the altitude of the respective cities were recorded. Early failure was defined as death, takedown of Fontan, or transplantation during the same hospital admission. The association between altitude and failure rate was investigated by rank correlation and logistic regression. Results 24 series were identified from centres situated at altitudes ranging from sea level to 520 metres. The plot of failure rate versus altitude suggests that failure rate increases with altitude. Logistic regression did not fit the data adequately. This was possibly due to the influence of unmeasured and unknown factors affecting the results, as well as the fact that centres were not randomly chosen but were self-selected by virtue of publishing their results. However, Spearman's rank correlation was 0.74 (p = 0.001. Conclusion The early outcome of the Fontan circulation appears to be adversely affected by altitude.

  14. Characteristics of flame spread over the surface of charring solid combustibles at high altitude

    Institute of Scientific and Technical Information of China (English)

    LI Jie; JI Jie; ZHANG Ying; SUN JinHua

    2009-01-01

    To explore the characteristics of flame spread over the surface of charring solid combustibles at high altitude, the whitewood with uniform texture was chosen to conduct a series of experiments in Lhasa and Hefei, with altitude of 3658 m and 50 m respectively. Several parameters, including the flame height, flame spread rate, flame temperature, surface temperature, were measured on samples with different width and inclinations. A quantitative analysis of flame spread characteristics over sample surface at high altitude was performed. Results showed that, in the environment of lower pressure and oxygen concentration at high altitude, the flame height and flame spread rate over sample surface decreased, but the flame temperature increased slightly. However, with increasing of sample width, the relative difference between the flame spread rates at different altitudes decreased.

  15. 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

  16. A 45-year-old man with excessive daytime somnolence, and witnessed apnea at altitude

    Directory of Open Access Journals (Sweden)

    Welsh CH

    2011-04-01

    Full Text Available A sleepy man without sleep apnea at 1609m (5280 feet had disturbed sleep at his home altitude of 3200m (10500 feet. In addition to common disruptors of sleep such as psychophysiologic insomnia, restless leg syndrome, alcohol and excessive caffeine use, central sleep apnea with periodic breathing can be a significant cause of disturbed sleep at altitude. In symptomatic patients living at altitude, a sleep study at their home altitude should be considered to accurately diagnose the presence and magnitude of sleep disordered breathing as sleep studies performed at lower altitudes may miss this diagnosis. Treatments options differ from those to treat obstructive apnea. Supplemental oxygen is considered by many to be first-line therapy.

  17. 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. PMID:26957629

  18. Effects of training at simulated altitude on performance and muscle metabolic capacity in competitive road cyclists.

    Science.gov (United States)

    Terrados, N; Melichna, J; Sylvén, C; Jansson, E; Kaijser, L

    1988-01-01

    Differences between the effects of training at sea level and at simulated altitude on performance and muscle structural and biochemical properties were investigated in 8 competitive cyclists who trained for 3-4 weeks, 4-5 sessions/week, each session consisting of cycling for 60-90 min continuously and 45-60 min intermittently. Four subjects, the altitude group (AG), trained in a hypobaric chamber (574 torr = 2300 m above sea level), and the other four at sea level (SLG). Before and after training work capacity was tested both at simulated altitude (574 torr) and at sea level, by an incremental cycle ergometer test until exhaustion. Work capacity was expressed as total amount of work performed. Venous blood samples were taken during the tests. Leg muscle biopsies were taken at rest before and after the training period. AG exhibited an increase of 33% in both sea level and altitude performance, while SLG increased 22% at sea level and 14% at altitude. Blood lactate concentration at a given submaximal load at altitude was significantly more reduced by training in AG than SLG. Muscle phosphofructokinase (PFK) activity decreased with training in AG but increased in SLG. All AG subjects showed increases in capillary density. In conclusion, work capacity at altitude was increased more by training at altitude than at sea level. Work capacity at sea level was at least as much improved by altitude as by sea level training. The improved work capacity by training at altitude was paralleled by decreased exercise blood lactate concentration, increased capillarization and decreased glycolytic capacity in leg muscle.

  19. High Altitude Venus Operational Concept (HAVOC): Proofs of Concept

    Science.gov (United States)

    Jones, Christopher A.; Arney, Dale C.; Bassett, George Z.; Clark, James R.; Hennig, Anthony I.; Snyder, Jessica C.

    2015-01-01

    The atmosphere of Venus is an exciting destination for both further scientific study and future human exploration. A recent internal NASA study of a High Altitude Venus Operational Concept (HAVOC) led to the development of an evolutionary program for the exploration of Venus, with focus on the mission architecture and vehicle concept for a 30-day crewed mission into Venus's atmosphere at 50 kilometers. Key technical challenges for the mission include performing the aerocapture maneuvers at Venus and Earth, inserting and inflating the airship at Venus during the entry sequence, and protecting the solar panels and structure from the sulfuric acid in the atmosphere. Two proofs of concept were identified that would aid in addressing some of the key technical challenges. To mitigate the threat posed by the sulfuric acid ambient in the atmosphere of Venus, a material was needed that could protect the systems while being lightweight and not inhibiting the performance of the solar panels. The first proof of concept identified candidate materials and evaluated them, finding FEP-Teflon (Fluorinated Ethylene Propylene-Teflon) to maintain 90 percent transmittance to relevant spectra even after 30 days of immersion in concentrated sulfuric acid. The second proof of concept developed and verified a packaging algorithm for the airship envelope to inform the entry, descent, and inflation analysis.

  20. Medium altitude airborne Geiger-mode mapping LIDAR system

    Science.gov (United States)

    Clifton, William E.; Steele, Bradley; Nelson, Graham; Truscott, Antony; Itzler, Mark; Entwistle, Mark

    2015-05-01

    Over the past 15 years the Massachusetts Institute of Technology, Lincoln Laboratory (MIT/LL), Defense Advanced Research Projects Agency (DARPA) and private industry have been developing airborne LiDAR systems based on arrays of Geiger-mode Avalanche Photodiode (GmAPD) detectors capable of detecting a single photon. The extreme sensitivity of GmAPD detectors allows operation of LiDAR sensors at unprecedented altitudes and area collection rates in excess of 1,000 km2/hr. Up until now the primary emphasis of this technology has been limited to defense applications despite the significant benefits of applying this technology to non-military uses such as mapping, monitoring critical infrastructure and disaster relief. This paper briefly describes the operation of GmAPDs, design and operation of a Geiger-mode LiDAR, a comparison of Geiger-mode and traditional linear mode LiDARs, and a description of the first commercial Geiger-mode LiDAR system, the IntelliEarth™ Geospatial Solutions Geiger-mode LiDAR sensor.

  1. Highlights from the High Altitude Water Cherenkov Observatory

    CERN Document Server

    Pretz, John

    2015-01-01

    The High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory was completed this year at a 4100-meter site on the flank of the Sierra Negra volcano in Mexico. HAWC is a water Cherenkov ground array with the capability to distinguish 100 GeV - 100 TeV gamma rays from the hadronic cosmic-ray background. HAWC is uniquely suited to study extremely high energy cosmic-ray sources, search for regions of extended gamma-ray emission, and to identify transient gamma-ray phenomena. HAWC will play a key role in triggering multi-wavelength and multi-messenger studies of active galaxies, gamma-ray bursts, supernova remnants and pulsar wind nebulae. Observation of TeV photons also provide unique tests for a number of fundamental physics phenomena including dark matter annihilation and primordial black hole evaporation. Operation began mid-2013 with the partially-completed detector. Multi-TeV emission from the Galactic Plane is clearly seen in the first year of operation, confirming a number of known TeV sources, and a numb...

  2. Atmospheric sub-3 nm particles at high altitudes

    Directory of Open Access Journals (Sweden)

    S. Mirme

    2010-01-01

    Full Text Available Formation of new atmospheric aerosol particles is known to occur almost all over the world and the importance of these particles to climate and air quality has been recognized. Recently, it was found that atmospheric aerosol particle formation begins at the diameter of around 1.5–2.0 nm and a pool of sub-3 nm atmospheric particles – consisting of both charged and uncharged ones – was observed at the ground level. Here, we report on the first airborne observations of the pool of sub-3 nm neutral atmospheric particles. Between 2 and 3 nm, their concentration is roughly two orders of magnitude larger than that of the ion clusters, depending slightly on the altitude. Our findings indicate that new particle formation takes place throughout the tropospheric column up to the tropopause. Particles were found to be formed via neutral pathways in the boundary layer, and there was no sign of an increasing role by ion-induced nucleation toward the upper troposphere. Clouds, while acting as a source of sub-10 nm ions, did not perturb the overall budget of atmospheric clusters or particles.

  3. Atmospheric sub-3 nm particles at high altitudes

    Directory of Open Access Journals (Sweden)

    S. Mirme

    2009-09-01

    Full Text Available Formation of new atmospheric aerosol particles is known to occur almost all over the world and the importance of these particles to climate and air quality has been recognized. Recently, it was found that atmospheric aerosol formation begins at particle diameter of around 1.5–2.0 nm and a pool of sub-3 nm atmospheric particles – consisting of both charged and uncharged ones – was observed at the ground level. Here, we report on the first airborne observations of the pool of sub-3 nm neutral atmospheric particles. Between 2 and 3 nm, their concentration is roughly two orders of magnitude larger than that of the ion clusters, depending slightly on the altitude. Our findings indicate that new particle formation takes place actively throughout the tropospheric column up to the tropopause. Particles were found to be formed via neutral pathways in the boundary layer, and there was no sign of an increasing role by ion-induced nucleation toward the upper troposphere. Clouds, while acting as a source of sub-10 nm ions, did not perturb the overall budget of atmospheric clusters or particles.

  4. Low-Altitude Magnetic Topology with MAVEN SWEA and MAG

    Science.gov (United States)

    Mitchell, David; Xu, Shaosui; Mazelle, Christian; Luhmann, Janet; McFadden, James; Connerney, John; Liemohn, Michael; Dong, Chuanfei; Bougher, Stephen; Fillingim, Matthew

    2016-04-01

    The Solar Wind Electron Analyzer (SWEA) and Magnetometer (MAG) onboard the MAVEN spacecraft measure electron pitch angle and energy distributions at 2-second resolution (~8 km along the orbit track) to determine the topology of magnetic fields from both external and crustal sources. Electrons from different regions of the Mars environment can be distinguished by their energy distributions. Thus, pitch angle resolved energy spectra can be used to determine the plasma source regions sampled by a field line at large distances from the spacecraft. From 12/1/2014 to 2/15/2015, when periapsis was at high northern latitudes, SWEA observed ionospheric photoelectrons at low altitudes (140-200 km) and high solar zenith angles (120-145 degrees) on ~35% of the orbits. Since this electron population is unambiguously produced in the dayside ionosphere, these observations demonstrate that the deep Martian nightside is at times magnetically connected to the sunlit hemisphere. The BATS-R-US Mars multi-fluid MHD model suggests the presence of closed crustal magnetic field lines over the northern hemisphere that straddle the terminator and extend to high SZA. Simulations with the SuperThermal Electron Transport (STET) model show that photoelectron transport along such field lines can take place without significant attenuation. Precipitation of photoelectrons onto the night-side atmosphere should cause ionization and possibly auroral emissions in localized regions. On one orbit, the O2+ energy flux measured by STATIC correlates well with precipitating photoelectron fluxes.

  5. Star formation in a diffuse high-altitude cloud?

    CERN Document Server

    Kerp, J; Roehser, T

    2016-01-01

    A recent discovery of two stellar clusters associated with the diffuse high-latitude cloud HRK 81.4-77.8 has important implications for star formation in the Galactic halo. We derive a plausible distance estimate to HRK 81.4-77.8 primarily from its gaseous properties. We spatially correlate state-of-the-art HI, far-infrared and soft X-ray data to analyze the diffuse gas in the cloud. The absorption of the soft X-ray emission from the Galactic halo by HRK 81.4-77.8 is used to constrain the distance to the cloud. HRK 81.4-77.8 is most likely located at an altitude of about 400 pc within the disk-halo interface of the Milky Way Galaxy. The HI data discloses a disbalance in density and pressure between the warm and cold gaseous phases. Apparently, the cold gas is compressed by the warm medium. This disbalance might trigger the formation of molecular gas high above the Galactic plane on pc to sub-pc scales.

  6. Solar regenerative fuel cell system for high altitude airships

    International Nuclear Information System (INIS)

    'Full text': A closed-loop regenerative fuel cell (RFC) system that serves as an energy storage device for space activities is studied through dynamic simulations. The unique nature of the closed-loop RFC makes it an ideal power system for key applications in homeland defense and earth observatory systems such as high altitude aircrafts /airships, unmanned aerial vehicles, and in planetary exploration for flyer or for surface power. The RFC considered using the photovoltaic cells to produce electric power during the day, part of which is used to produce hydrogen and oxygen through electrolysis. The stored hydrogen and oxygen is used through a fuel cell to produce electric power during night hours. A MATLAB/SIMULINK model was developed for the components of the RFC that include a fuel cell, electrolyzer, photovoltaic solar array, power bus, humidifiers, compressor/motor assembly, expander, pumps, phase separators, storage tanks for hydrogen, oxygen and water, control valves and piping, electric grid system and controls. A proton exchange membrane (PEM) fuel cell and PEM electrolyzer were modeled in detail that included the mass momentum, energy, chemical reaction rates at cathode and anode. The PEM fuel cell voltage was modeled accounting cell activation and ohmic polarizations. A modular approach was used to develop models for each component. Component models were based on fundamental physics to the extent practical. Steady state and dynamic response of the RFC for different operational conditions including start-up, shut down, load changes and (accidental) transients was studied. (author)

  7. Latest news from the High Altitude Water Cherenkov Observatory

    Science.gov (United States)

    González Muñoz, A.; HAWC Collaboration

    2016-07-01

    The High Altitude Water Cherenkov Observatory is an air shower detector designed to study very-high-energy gamma rays (∼ 100 GeV to ∼ 100 TeV). It is located in the Pico de Orizaba National Park, Mexico, at an elevation of 4100 m. HAWC started operations since August 2013 with 111 tanks and in April of 2015 the 300 tanks array was completed. HAWC's unique capabilities, with a field of view of ∼ 2 sr and a high duty cycle of 5%, allow it to survey 2/3 of the sky every day. These features makes HAWC an excellent instrument for searching new TeV sources and for the detection of transient events, like gamma-ray bursts. Moreover, HAWC provides almost continuous monitoring of already known sources with variable gamma-ray fluxes in most of the northern and part of the southern sky. These observations will bring new information about the acceleration processes that take place in astrophysical environments. In this contribution, some of the latest scientific results of the observatory will be presented.

  8. Earth's external magnetic fields at low orbital altitudes

    Science.gov (United States)

    Klumpar, D. M.

    1990-01-01

    Under our Jun. 1987 proposal, Magnetic Signatures of Near-Earth Distributed Currents, we proposed to render operational a modeling procedure that had been previously developed to compute the magnetic effects of distributed currents flowing in the magnetosphere-ionosphere system. After adaptation of the software to our computing environment we would apply the model to low altitude satellite orbits and would utilize the MAGSAT data suite to guide the analysis. During the first year, basic computer codes to run model systems of Birkeland and ionospheric currents and several graphical output routines were made operational on a VAX 780 in our research facility. Software performance was evaluated using an input matchstick ionospheric current array, field aligned currents were calculated and magnetic perturbations along hypothetical satellite orbits were calculated. The basic operation of the model was verified. Software routines to analyze and display MAGSAT satellite data in terms of deviations with respect to the earth's internal field were also made operational during the first year effort. The complete set of MAGSAT data to be used for evaluation of the models was received at the end of the first year. A detailed annual report in May 1989 described these first year activities completely. That first annual report is included by reference in this final report. This document summarizes our additional activities during the second year of effort and describes the modeling software, its operation, and includes as an attachment the deliverable computer software specified under the contract.

  9. Deducing high-altitude precipitation from glacier mass balance measurements

    Science.gov (United States)

    Giesen, Rianne H.; Immerzeel, Walter W.; Wanders, Niko

    2016-04-01

    The spatial distribution of precipitation in mountainous terrain is generally not well known due to underrepresentation of gauge observations at higher elevations. Precipitation tends to increase with elevation, but since observations are mainly performed in the valleys, the vertical precipitation gradient cannot be deduced from these measurements. Furthermore, the spatial resolution of gridded meteorological data is often too coarse to resolve individual mountain chains. Still, a reliable estimate of high-elevation precipitation is required for many hydrological applications. We present a method to determine the vertical precipitation gradient in mountainous terrain, making use of glacier mass balance observations. These measurements have the advantage that they provide a basin-wide precipitation estimate at high elevations. The precipitation gradient is adjusted until the solid precipitation over the glacier area combined with the calculated melt gives the measured annual glacier mass balance. Results for the glacierized regions in Central Europe and Scandinavia reveal spatially coherent patterns, with predominantly positive precipitation gradients ranging from -4 to +28 % (100 m)‑1. In some regions, precipitation amounts at high elevations are up to four times as large as in the valleys. A comparison of the modelled winter precipitation with observed snow accumulation on glaciers shows a good agreement. Precipitation measured at the few high-altitude meteorological stations is generally lower than our estimate, which may result from precipitation undercatch. Our findings will improve the precipitation forcing for glacier modelling and hydrological studies in mountainous terrain.

  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. 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

  12. Safely Enabling Civilian Unmanned Aerial System (UAS) Operations in Low-Altitude Airspace by Unmanned Aerial System Traffic Management (UTM)

    Science.gov (United States)

    Kopardekar, Parimal Hemchandra

    2015-01-01

    Many UAS will operate at lower altitude (Class G, below 2000 feet). There is an urgent need for a system for civilian low-altitude airspace and UAS operations. Stakeholders want to work with NASA to enable safe operations.

  13. Barcroft's bold assertion: All dwellers at high altitudes are persons of impaired physical and mental powers.

    Science.gov (United States)

    West, John B

    2016-03-01

    Barcroft's bold assertion that everyone at high altitude has physical and mental impairment compared with sea level was very provocative. It was a result of the expedition that he led to Cerro de Pasco in Peru, altitude 4300 m. Although it is clear that newcomers to high altitude have reduced physical powers, some people believe that this does not apply to permanent residents who have been at high altitude for generations. The best evidence supports Barcroft's contention, although permanent residents often perform better than acclimatized lowlanders. Turning to neuropsychological function, newcomers to high altitude certainly have some impairment, and there is evidence that the same applies to highlanders. However the notion that permanent residents are impaired is anathema to many people. For example the eminent Peruvian physician Carlos Monge took great exception to Barcroft's remark and even attributed it to the fact that Barcroft was suffering from acute mountain sickness when he made it! Monge referred to 'climatic aggression', by which he meant the negative consequences of the inevitable hypoxia of high altitude. Recent technological advances such as oxygen enrichment of room air can overcome this 'aggression'. This might be useful in some settings at high altitude such as a nursery where newborn babies are cared for, and possibly operating rooms where the surgeon's dexterity may be enhanced. Other situations might be dormitories, conference rooms, and perhaps some school rooms. These constitute possible ways by which the effects of Barcroft's assertion might be countered. PMID:25962370

  14. Barcroft's bold assertion: All dwellers at high altitudes are persons of impaired physical and mental powers.

    Science.gov (United States)

    West, John B

    2016-03-01

    Barcroft's bold assertion that everyone at high altitude has physical and mental impairment compared with sea level was very provocative. It was a result of the expedition that he led to Cerro de Pasco in Peru, altitude 4300 m. Although it is clear that newcomers to high altitude have reduced physical powers, some people believe that this does not apply to permanent residents who have been at high altitude for generations. The best evidence supports Barcroft's contention, although permanent residents often perform better than acclimatized lowlanders. Turning to neuropsychological function, newcomers to high altitude certainly have some impairment, and there is evidence that the same applies to highlanders. However the notion that permanent residents are impaired is anathema to many people. For example the eminent Peruvian physician Carlos Monge took great exception to Barcroft's remark and even attributed it to the fact that Barcroft was suffering from acute mountain sickness when he made it! Monge referred to 'climatic aggression', by which he meant the negative consequences of the inevitable hypoxia of high altitude. Recent technological advances such as oxygen enrichment of room air can overcome this 'aggression'. This might be useful in some settings at high altitude such as a nursery where newborn babies are cared for, and possibly operating rooms where the surgeon's dexterity may be enhanced. Other situations might be dormitories, conference rooms, and perhaps some school rooms. These constitute possible ways by which the effects of Barcroft's assertion might be countered.

  15. Sensitization pattern of inhalant allergens in children with asthma who are living different altitudes in Turkey

    Science.gov (United States)

    Ozkaya, Emin; Sogut, Ayhan; Küçükkoç, Mehmet; Eres, Mustafa; Acemoglu, Hamit; Yuksel, Hasan; Murat, Naci

    2015-11-01

    Variability in children's allergic sensitization has been detected not only among different countries but also among cities within the same nation but yet different climatic areas. The aim of this study was to investigate the sensitization pattern of asthmatic children who lived in different altitude areas: the two largest Turkish cities, Istanbul (sea level) and Erzurum (high altitude). Five hundred and twelve asthmatic children (6-15 years old) from Istanbul (western Turkey, at sea level) and 609 from Erzurum (eastern Turkey, at an altitude of 1800 m) were included in the study. All participants underwent skin testing with common inhalant allergens, spirometry, total IgE level, and clinical examination. The positive sensitization ratio to aeroallergens in children with asthma living at sea level was statistically higher than that in children living in the high altitude group [ p = 0.001, OR (odds ratio) 4.9 (confidence interval (CI) 3.67-6.459)]. However, pollen sensitization in asthmatic children living in high altitudes was significantly higher than that in children living at sea level [ p = 0.00, OR 2.6 (CI 1.79-3.87)]. Children with asthma who live at high altitudes are characterized by higher pollen but lower mite sensitization rates than those living at sea level in Turkey. Different climatic conditions and altitudes may affect aeroallergen sensitization in children with asthma.

  16. Acetazolamide pre-treatment before ascending to high altitudes: when to start?

    Science.gov (United States)

    Burtscher, Martin; Gatterer, Hannes; Faulhaber, Martin; Burtscher, Johannes

    2014-01-01

    Hypoxia is the main responsible factor initiating the symptoms of acute mountain sickness (AMS) in susceptible individuals. Measures that improve oxygenation and/or hasten acclimatization like pre-treatment with acetazolamide will prevent the development of AMS. We hypothesized that pre-treatment with acetazolamide the day before arrival at high altitude would elicit improved oxygenation compared to placebo not until the second day of high-altitude exposure. Fifteen study participants were randomly assigned in a double blind fashion to receive placebo or acetazolamide (2 × 125 mg) before (10 hours and 1 hour) exposure to high altitude (Monte Rosa plateau, 3480 m). Beside AMS scoring, heart rate, minute ventilation, and blood gas analyses were performed during rest and submaximal exercise at low altitude and on day 1, 2 and 3 at high altitude. From low altitude to day 1 at high altitude changes of pH (7.41 ± 0.01 vs. 7.48 ± 0.04) and HCO3 (24.0 ± 0.46 vs. 24.6 ± 2.6 mmol/L) within the placebo group differed significantly from those within the acetazolamide group (7.41 ± 0.01 vs. 7.41 ± 0.02; 23.6 ± 0.38 vs. 20.7 ± 1.8 mmol/L) (P effect on AMS development. PMID:25550957

  17. Sensitization pattern of inhalant allergens in children with asthma who are living different altitudes in Turkey.

    Science.gov (United States)

    Ozkaya, Emin; Sogut, Ayhan; Küçükkoç, Mehmet; Eres, Mustafa; Acemoglu, Hamit; Yuksel, Hasan; Murat, Naci

    2015-11-01

    Variability in children's allergic sensitization has been detected not only among different countries but also among cities within the same nation but yet different climatic areas. The aim of this study was to investigate the sensitization pattern of asthmatic children who lived in different altitude areas: the two largest Turkish cities, Istanbul (sea level) and Erzurum (high altitude). Five hundred and twelve asthmatic children (6-15 years old) from Istanbul (western Turkey, at sea level) and 609 from Erzurum (eastern Turkey, at an altitude of 1800 m) were included in the study. All participants underwent skin testing with common inhalant allergens, spirometry, total IgE level, and clinical examination. The positive sensitization ratio to aeroallergens in children with asthma living at sea level was statistically higher than that in children living in the high altitude group [p = 0.001, OR (odds ratio) 4.9 (confidence interval (CI) 3.67-6.459)]. However, pollen sensitization in asthmatic children living in high altitudes was significantly higher than that in children living at sea level [p = 0.00, OR 2.6 (CI 1.79-3.87)]. Children with asthma who live at high altitudes are characterized by higher pollen but lower mite sensitization rates than those living at sea level in Turkey. Different climatic conditions and altitudes may affect aeroallergen sensitization in children with asthma.

  18. Regional differences in the cerebral blood flow velocity response to hypobaric hypoxia at high altitudes.

    Science.gov (United States)

    Feddersen, Berend; Neupane, Pritam; Thanbichler, Florian; Hadolt, Irmgard; Sattelmeyer, Vera; Pfefferkorn, Thomas; Waanders, Robb; Noachtar, Soheyl; Ausserer, Harald

    2015-11-01

    Symptoms of acute mountain sickness (AMS) may appear above 2,500 m altitude, if the time allowed for acclimatization is insufficient. As the mechanisms underlying brain adaptation to the hypobaric hypoxic environment are not fully understood, a prospective study was performed investigating neurophysiological changes by means of near infrared spectroscopy, electroencephalograpy (EEG), and transcranial doppler sonography at 100, 3,440 and 5,050 m above sea level in the Khumbu Himal, Nepal. Fourteen of the 26 mountaineers reaching 5,050 m altitude developed symptoms of AMS between 3,440 and 5,050 m altitude (Lake-Louise Score ⩾3). Their EEG frontal beta activity and occipital alpha activity increased between 100 and 3,440 m altitude, i.e., before symptoms appeared. Cerebral blood flow velocity (CBFV) in the anterior and middle cerebral arteries (MCAs) increased in all mountaineers between 100 and 3,440 m altitude. During further ascent to 5,050 altitude, mountaineers with AMS developed a further increase in CBFV in the MCA, whereas in all mountaineers CBFV decreased continuously with increasing altitude in the posterior cerebral arteries. These results indicate that hypobaric hypoxia causes different regional changes in CBFV despite similar electrophysiological changes.

  19. Identification of novel serum peptide biomarkers for high-altitude adaptation: a comparative approach

    Science.gov (United States)

    Yang, Juan; Li, Wenhua; Liu, Siyuan; Yuan, Dongya; Guo, Yijiao; Jia, Cheng; Song, Tusheng; Huang, Chen

    2016-05-01

    We aimed to identify serum biomarkers for screening individuals who could adapt to high-altitude hypoxia at sea level. HHA (high-altitude hypoxia acclimated; n = 48) and HHI (high-altitude hypoxia illness; n = 48) groups were distinguished at high altitude, routine blood tests were performed for both groups at high altitude and at sea level. Serum biomarkers were identified by comparing serum peptidome profiling between HHI and HHA groups collected at sea level. Routine blood tests revealed the concentration of hemoglobin and red blood cells were significantly higher in HHI than in HHA at high altitude. Serum peptidome profiling showed that ten significantly differentially expressed peaks between HHA and HHI at sea level. Three potential serum peptide peaks (m/z values: 1061.91, 1088.33, 4057.63) were further sequence identified as regions of the inter-α trypsin inhibitor heavy chain H4 fragment (ITIH4 347-356), regions of the inter-α trypsin inhibitor heavy chain H1 fragment (ITIH1 205-214), and isoform 1 of fibrinogen α chain precursor (FGA 588-624). Expression of their full proteins was also tested by ELISA in HHA and HHI samples collected at sea level. Our study provided a novel approach for identifying potential biomarkers for screening people at sea level who can adapt to high altitudes.

  20. Identification of novel serum peptide biomarkers for high-altitude adaptation: a comparative approach

    Science.gov (United States)

    Yang, Juan; Li, Wenhua; Liu, Siyuan; Yuan, Dongya; Guo, Yijiao; Jia, Cheng; Song, Tusheng; Huang, Chen

    2016-05-01

    We aimed to identify serum biomarkers for screening individuals who could adapt to high-altitude hypoxia at sea level. HHA (high-altitude hypoxia acclimated; n = 48) and HHI (high-altitude hypoxia illness; n = 48) groups were distinguished at high altitude, routine blood tests were performed for both groups at high altitude and at sea level. Serum biomarkers were identified by comparing serum peptidome profiling between HHI and HHA groups collected at sea level. Routine blood tests revealed the concentration of hemoglobin and red blood cells were significantly higher in HHI than in HHA at high altitude. Serum peptidome profiling showed that ten significantly differentially expressed peaks between HHA and HHI at sea level. Three potential serum peptide peaks (m/z values: 1061.91, 1088.33, 4057.63) were further sequence identified as regions of the inter-α trypsin inhibitor heavy chain H4 fragment (ITIH4 347–356), regions of the inter-α trypsin inhibitor heavy chain H1 fragment (ITIH1 205–214), and isoform 1 of fibrinogen α chain precursor (FGA 588–624). Expression of their full proteins was also tested by ELISA in HHA and HHI samples collected at sea level. Our study provided a novel approach for identifying potential biomarkers for screening people at sea level who can adapt to high altitudes.

  1. 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

  2. Transpulmonary plasma ET-1 and nitrite differences in high altitude pulmonary hypertension.

    Science.gov (United States)

    Berger, Marc M; Dehnert, Christoph; Bailey, Damian M; Luks, Andrew M; Menold, Elmar; Castell, Christian; Schendler, Guido; Faoro, Vitalie; Mairbäurl, Heimo; Bärtsch, Peter; Swenson, Erik R

    2009-01-01

    Berger, Marc M., Christoph Dehnert, Damian M. Bailey, Andrew M. Luks, Elmar Menold, Christian Castell, Guido Schendler, Vitalie Faoro, Heimo Mairbäurl, Peter Bärtsch, and Eric R. Swenson. Transpulmonary plasma ET-1 and nitrite differences in high altitude pulmonary hypertension. High Alt. Med. Biol. 10:17-24, 2009.- Thirty-four mountaineers were studied at low (110 m) and high altitude (4559 m) to evaluate if increased pulmonary artery systolic pressure (PASP) at high altitude is associated with increased pulmonary endothelin-1 (ET-1) availability and alterations in nitrite metabolism across the lung. Blood samples were obtained using central venous and radial artery catheters for plasma ET-1 and nitrite. Pulmonary blood flow was measured by inert gas rebreathing to calculate transpulmonary exchange of plasma ET-1 and nitrite, and PASP was assessed by transthoracic Doppler echocardiography. After ascent to high altitude, PASP increased from 23 +/- 4 to 39 +/- 10 mmHg. Arterial and central venous plasma ET-1 increased, while plasma nitrite did not change significantly. At low altitude there was a transpulmonary loss of plasma ET-1, but a transpulmonary gain at high altitude. In contrast was a transpulmonary gain of plasma nitrite at low altitude and a transpulmonary loss at high altitude. PASP positively correlated with a transpulmonary gain of plasma ET-1 and negatively correlated with a transpulmonary loss of plasma nitrite. These results suggest that a transpulmonary gain of plasma ET- 1 is associated with higher PASP at high altitude. Transpulmonary loss of plasma nitrite indicates either less pulmonary nitric oxide (NO) production, which contributes to higher PASP, or increased NO bioavailability arising from nitrite reduction, which may oppose ET-1-mediated vasoconstriction.

  3. Persistent organic pollutants (POPs) as environmental risk factors in remote high-altitude ecosystems.

    Science.gov (United States)

    Kallenborn, Roland

    2006-01-01

    Persistent organic pollutants (POPs), and their transformation products, are the most investigated organic environmental contaminants within the past five decades. Organochlorines have been found in virtually all environmental compartments on the globe. Severe environmental implications have been shown to be associated with the presence of the POP group of contaminants in the environment. However, in the late 1990s, Canadian scientists first pinpointed the implication of POPs for high-altitude environments in a comprehensive way (Blais et al., 1998, Nature 395, 585-588). Under certain meteorological and geographic conditions, high-altitude environments can serve as "cold condensers" for atmospheric POP loadings. Subsequent investigations in high-altitude environments in Asia, Europe, and North and South America have confirmed suspicions that high-altitude mountainous regions have the potential to serve as focus regions for POPs and even for nonpersistent, medium-lived contaminants, such as "currently used pesticides", due to cold condensation and deposition in high altitudes. Although the presence and the altitude-dependent increase of POP levels in mountainous regions are confirmed by many international studies, the ecotoxicological consequences still remain largely unknown. At present, only a few studies have been published describing the biological effects in high-altitude environments due to increased POP exposure. Therefore, in this early stage of the international research effort on the ecotoxicological risk evaluation of persistent contaminants in high-altitude, pristine ecosystems, the present review intends to summarize the current state of research on POPs in high-altitude environments and draw preliminary conclusions on possible consequences of the presence of POPs in mountainous ecosystems based on currently available information from alpine and related Arctic environments. PMID:16399161

  4. Quantitative changes in the sleep EEG at moderate altitude (1630 m and 2590 m.

    Directory of Open Access Journals (Sweden)

    Katrin Stadelmann

    Full Text Available BACKGROUND: Previous studies have observed an altitude-dependent increase in central apneas and a shift towards lighter sleep at altitudes >4000 m. Whether altitude-dependent changes in the sleep EEG are also prevalent at moderate altitudes of 1600 m and 2600 m remains largely unknown. Furthermore, the relationship between sleep EEG variables and central apneas and oxygen saturation are of great interest to understand the impact of hypoxia at moderate altitude on sleep. METHODS: Fourty-four healthy men (mean age 25.0 ± 5.5 years underwent polysomnographic recordings during a baseline night at 490 m and four consecutive nights at 1630 m and 2590 m (two nights each in a randomized cross-over design. RESULTS: Comparison of sleep EEG power density spectra of frontal (F3A2 and central (C3A2 derivations at altitudes compared to baseline revealed that slow-wave activity (SWA, 0.8-4.6 Hz in non-REM sleep was reduced in an altitude-dependent manner (~4% at 1630 m and 15% at 2590 m, while theta activity (4.6-8 Hz was reduced only at the highest altitude (10% at 2590 m. In addition, spindle peak height and frequency showed a modest increase in the second night at 2590 m. SWA and theta activity were also reduced in REM sleep. Correlations between spectral power and central apnea/hypopnea index (AHI, oxygen desaturation index (ODI, and oxygen saturation revealed that distinct frequency bands were correlated with oxygen saturation (6.4-8 Hz and 13-14.4 Hz and breathing variables (AHI, ODI; 0.8-4.6 Hz. CONCLUSIONS: The correlation between SWA and AHI/ODI suggests that respiratory disturbances contribute to the reduction in SWA at altitude. Since SWA is a marker of sleep homeostasis, this might be indicative of an inability to efficiently dissipate sleep pressure.

  5. Physiological and Clinical Implications of Adrenergic Pathways at High Altitude.

    Science.gov (United States)

    Richalet, Jean-Paul

    2016-01-01

    The adrenergic system is part of a full array of mechanisms allowing the human body to adapt to the hypoxic environment. Triggered by the stimulation of peripheral chemoreceptors, the adrenergic centers in the medulla are activated in acute hypoxia and augment the adrenergic drive to the organs, especially to the heart, leading to tachycardia. With prolonged exposure to altitude hypoxia, the adrenergic drive persists, as witnessed by elevated blood concentrations of catecholamines and nerve activity in adrenergic fibers. In response to this persistent stimulation, the pathways leading to the activation of adenylate cyclase are modified. A downregulation of β-adrenergic and adenosinergic receptors is observed, while muscarinic receptors are upregulated. The expression and activity of Gi and Gs proteins are modified, leading to a decreased response of adenylate cyclase activity to adrenergic stimulation. The clinical consequences of these cellular and molecular changes are of importance, especially for exercise performance and protection of heart function. The decrease in maximal exercise heart rate in prolonged hypoxia is fully accounted for the observed changes in adrenergic and muscarinic pathways. The decreased heart rate response to isoproterenol infusion is another marker of the desensitization of adrenergic pathways. These changes can be considered as mechanisms protecting the heart from a too high oxygen consumption in conditions where the oxygen availability is severely reduced. Similarly, intermittent exposure to hypoxia has been shown to protect the heart from an ischemic insult with similar mechanisms involving G proteins and downregulation of β receptors. Other pathways with G proteins are concerned in adaptation to hypoxia, such as lactate release by the muscles and renal handling of calcium. Altogether, the activation of the adrenergic system is useful for the acute physiological response to hypoxia. With prolonged exposure to hypoxia, the autonomous

  6. Hands-on Space Exploration through High Altitude Ballooning

    Science.gov (United States)

    Hammergren, Mark; Gyuk, G.

    2010-01-01

    The Adler Planetarium's "Far Horizons" high-altitude ballooning effort serves as the focus for a diverse set of educational activities, including middle school summer camps, a high school summer program (the Astro-Science Workshop), school-year internships for high school students, summer internships for undergraduates, a NSF-funded graduate fellowship, and a thriving public volunteer program. The relatively low costs of both the reusable hardware (less than $1000) and expendable supplies (around $150 per launch) allow us to mount frequent missions throughout the year - and make such a program ideal for replication at institutions of any size. The rapid development schedule for each individual mission permits the cradle-to-grave involvement of short-term participants, making it easy to draw in a wide audience. Students are involved literally in a hands-on manner in all aspects of the construction, launch, tracking, and recovery of simple experimental payloads, which typically include sensors for temperature, pressure, light intensity, and radiation. Stunning imagery provided by onboard cameras can attract significant media interest, which can bring outreach efforts to a very broad audience. Future plans include the design and construction of CubeSats - decimeter-sized picosatellites carried to orbit as secondary payloads. Our first satellite will be a relatively simple Earth-imager, built from commercial, off-the-shelf components. As in the ballooning program, students and volunteers will be involved in all stages of this effort. Once operational, imagery and other data from the satellite will be incorporated into a museum exhibit that will allow visitors to submit target requests. This material is based in part upon work supported by the National Science Foundation under Grant No. 0525995.

  7. High-altitude paragangliomas diagnostic and therapeutic considerations.

    Science.gov (United States)

    Rodriguez-Cuevas, H; Lau, I; Rodriguez, H P

    1986-02-01

    Forty-one cervical paragangliomas that occurred in 40 patients born and living in Mexico City, Mexico, were studied. Tumors were most common in women (38/40); were unilateral (39/40), without a side preference; were of the nonhereditary type; and were not malignant. Tumor imaging with radionucleaide angiographic scanning was noninvasive, innocuous, and reliable for screening, whereas selective carotid angiography allowed for definitive diagnosis and clinical stratification of patients. Surgical resection was performed in 29 patients; in 23 cases, en bloc resection was accomplished without a vascular compromise, whereas in 4 patients, a portion of the external carotid artery had to be ligated and resected. Two other patients required a vascular graft to restore blood flow to the internal carotid. Seven patients had postoperative transient cranial nerve palsies, and one had an incomplete hemiplegia. Permanent nerve damage occurred in seven patients. It was concluded that high-altitude paragangliomas are hyperplastic growths that result from adaptation to hypoxia. They are rarely true neoplasm and, in general, are not associated with functional loss. In view of this and of the high morbidity rate associated with surgical removal, it was recommended that these patients be referred to research centers where efforts toward the elucidation of the etiology and pathophysiology of these tumors can be carried out. Surgery should be reserved for symptomatic cases or cases in which the diagnosis remains in doubt. The decision to operate must weigh the following factors: The tumor's benign nature, its slow growth rate, the technical difficulties associated with its resection, the high postoperative morbidity rate, and the general condition of the patient. PMID:3943005

  8. High Altitude Aerial Natural Gas Leak Detection System

    Energy Technology Data Exchange (ETDEWEB)

    Richard T. Wainner; Mickey B. Frish; B. David Green; Matthew C. Laderer; Mark G. Allen; Joseph R. Morency

    2006-12-31

    The objective of this program was to develop and demonstrate a cost-effective and power-efficient advanced standoff sensing technology able to detect and quantify, from a high-altitude (> 10,000 ft) aircraft, natural gas leaking from a high-pressure pipeline. The advanced technology is based on an enhanced version of the Remote Methane Leak Detector (RMLD) platform developed previously by Physical Sciences Inc. (PSI). The RMLD combines a telecommunications-style diode laser, fiber-optic components, and low-cost DSP electronics with the well-understood principles of Wavelength Modulation Spectroscopy (WMS), to indicate the presence of natural gas located between the operator and a topographic target. The transceiver transmits a laser beam onto a topographic target and receives some of the laser light reflected by the target. The controller processes the received light signal to deduce the amount of methane in the laser's path. For use in the airborne platform, we modified three aspects of the RMLD, by: (1) inserting an Erbium-doped optical fiber laser amplifier to increase the transmitted laser power from 10 mW to 5W; (2) increasing the optical receiver diameter from 10 cm to 25 cm; and (3) altering the laser wavelength from 1653 nm to 1618 nm. The modified RMLD system provides a path-integrated methane concentration sensitivity {approx}5000 ppm-m, sufficient to detect the presence of a leak from a high capacity transmission line while discriminating against attenuation by ambient methane. In ground-based simulations of the aerial leak detection scenario, we demonstrated the ability to measure methane leaks within the laser beam path when it illuminates a topographic target 2000 m away. We also demonstrated simulated leak detection from ranges of 200 m using the 25 cm optical receiver without the fiber amplifier.

  9. Lidar observations of high-altitude aerosol layers (cirrus clouds)

    Science.gov (United States)

    Deleva, Atanaska D.; Grigorov, Ivan V.

    2013-03-01

    Aerosols, clouds and aerosol-cloud interactions are recognized as the key factors influencing the climate. Clouds are the primary modulators of the Earth's radiative budget. This paper focuses on the detection of high-altitude aerosol layers in the troposphere over mid-latitude lidar station in Sofia, Bulgaria. They are situated in the height-region 6 km÷16 km, with thickness in the range 0.2 km÷5 km and have varying optical characteristics. On the basis of the general utilized classification of the Cirrus clouds, high values of the calculated atmospheric backscatter coefficient and Angströmexponent estimation results we conclude that the registered strongly scattered aerosol layers are Cirrus clouds. Lidar measurements are performed with an aerosol lidar, equipped with Nd:YAG laser at wavelengths 532 nm and 1064 nm. Mainly, lidar data are presented in terms of vertical atmospheric backscatter coefficient profiles. We also include 2Dcolormap in height-time coordinates build on the basis of so called range corrected signals. It shows in general changes of the aerosol stratification over the lidar station during the measurement period. We employed HYSPLIT backward trajectories and DREAM forecasts to analyze the lidar profile outlines and characterize the events during which Cirrus cloud samples were observed. So was remarked that most of the results were obtained during Saharan dust long-way transport over the city of Sofia. Reported experimental examples are extracted from regular lidar investigations of the atmosphere within the frame of European project EARLINET.

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

    International Nuclear Information System (INIS)

    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

  11. Effects of altitude above sea level on the cooking time and nutritional value of common beans.

    Science.gov (United States)

    Bressani, R; Chon, C

    1996-01-01

    The present study was conducted with the objective to determine the effects of altitude above sea level, on the cooking time and nutritional value of common black beans (Phaseolus vulgaris). Three 100 g samples of the Ostua variety were cooked at 8 individual locations, ranging in altitude from 0 to 2256 meters, in Guatemala, to establish water uptake and cooking time. The cooked samples were separated into cooked beans and cooking broth for chemical analysis. This included moisture, protein, lysine, tannins, total and enzyme susceptible starch, and fiber fractionation. The cooking liquor was analyzed for total solids, moisture, protein, ash and K. A 1200 g sample was cooked for the cooking time established previously, for biological testing of nutritional value, which included Net Protein Ratio (NPR), Protein Efficiency Ratio (PER), and protein digestibility. Altitude influenced cooking time which increased from 78 min at 0 m, to 264 min at 2256 m. Final moisture content in the cooked bean was similar at all altitudes and there was a tendency to yield smaller amounts of solids in the cooking broth at higher altitudes. The increase in cooking time was significant. Bean water uptake at all times was significantly slower and smaller at ambient as compared to water uptake at boiling T, at all altitudes. Protein and lysine content were not affected by altitude, however, tannin and catechin were lower in cooked samples, as compared to the raw material. Altitude did not affect the content of these substances. Total starch and total sugars were higher in the raw sample, as compared to the cooked samples, but there was no effect of altitude. Enzyme susceptible starch (ESS) was lower in the raw sample as compared to the cooked samples, which contained similar amounts with respect to altitude. No change was observed in fiber fractions of the cooked beans. Likewise, the composition of the cooking broth was very similar between cooking locations. There was a small tendency to

  12. HSP70 expression in the copper butterfly Lycaena tityrus across altitudes and temperatures

    DEFF Research Database (Denmark)

    Karl, I.; Sørensen, Jesper Givskov; Loeschcke, Volker;

    2009-01-01

    The ability to express heat-shock proteins (HSP) under thermal stress is an essential mechanism for ectotherms to cope with unfavourable conditions. In this study, we investigate if Copper butterflies originating from different altitudes and/or being exposed to different rearing and induction...... temperatures show differences in HSP70 expression. HSP70 expression increased substantially at the higher rearing temperature in low-altitude butterflies, which might represent an adaptation to occasionally occurring heat spells. On the other hand, high-altitude butterflies showed much less plasticity...

  13. Does high altitude increase risks of the elderly patients with coronary artery disease?

    Institute of Scientific and Technical Information of China (English)

    Tian-Yi Wu; Zhong-Yan Zhan; Qin-Li Wu; Suo-Lung Baomu; Yu-Ling Jie; Min Sun

    2009-01-01

    Objective To assess the effect of altitude hypoxia on the elderly patients with coronary artery disease (CAD). Methods Three subject groups were surveyed during their train trip on the highest railroad--the Qinghai-Tibet Railway: 22 elderly individuals with documented CAD, 20 healthy elderly controls, and 20 healthy young controls, all of whom from Beijing near the sea level (76 m). Survey questions addressed clinical features of their healthy conditions and aspects of their coronary disease. The baseline study was performed at Xining at an altitude of 2261 m, and then during acute exposure to altitudes of 2808 m, 4768m, 5072 m and 4257 m by train for 24 hours. Resting pulse rate, blood pressure, oxygen saturation, electrocardiograph (ECG), and cardiac work estimated by the heart rate-blood pressure double product were obtained five times in each subject at different altitudes. Results On arrival to altitudes between 4768 m and 5072 m, the older passengers, especially those with preexisting coronary disease, had higher HR, higher BP, and lower SaO2, as well as more frequent abnormalities on ECG, as compared to the younger healthy subjects. As compared with the healthy elderly controls, incomplete right bundle branch block, left ventricular hypertrophy, and ST segment depression were more frequently seen in the elderly coronary patients (P<0.01). Cardiac work in group 1 was increased by 13% 12 hours after arrival to altitudes between 2808 m and 5072 m. Oxygen saturation decreased significantly with the altitude increasing by train ascent but improved after inhalation of oxygen. Most of the older subjects tolerated their sojourn at high altitude well except one who developed angina repeatedly with a significant ST segment depression. Conclusions Coronary events and ECG signs of myocardial ischemia are rare in elderly individuals with CAD who travel from sea level to moderate altitudes of 1500m to 2800 m. Patients with CAD who are well compensated at sea level

  14. Research on the Key Technology of Large Scale Mapping from Low Altitude Photogrammetry

    Science.gov (United States)

    Bo-Yi, Wu; Ning, Zhang; Guo-Zhong, Su

    2016-06-01

    Based on the theoretic analysis of the accuracy in large scale photogrammetric mapping, some defects in traditional procedure were discussed. A set of key technologies dedicate to accuracy improvement in low altitude photogrammetry were analyzed in detail, namely the utilization of wide angle camera and low altitude flight, enhancement in image matching, predesigned layout of Ground Control Points (GCPs) in field survey, optimization of adjustment model and improvement in map processing. Besides, a low altitude aerial unmanned airship system was established. Finally, successful implementation in 1:500 topographic mapping project in built-up areas of 30 counties in Shanxi Province proves the practicability and effectiveness of the proposed approaches.

  15. 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

  16. High Altitude Airship Altitude Control System Design and Simulation%高空飞艇高度控制系统设计及仿真

    Institute of Scientific and Technical Information of China (English)

    凡永华; 于云峰; 闰杰

    2011-01-01

    The high altitude airship can not have desired performance to control the altitude rapidly and accurately when the elevator and ancillary air bursa charge or deflation are used only, because the elevator has few efficiency when the velocity is low, and auxiliary ballonet charge or deflation control is very slow. A method is presented to design altitude control system for a high altitude airship using auxiliary ballonet charge or deflation and elevator combination control. This combination control scheme is that the ancillary air bursa and elevator are also used to control the airship attitude to get large raise velocity and the ancillary air bursa control is used to adjust the airship altitude for suspension. In this paper, a high altitude airship model with compound control of elevator and ancillary air bursa charging and deflation is given firstly. Then the optimum control is depicted to design the altitude control system for a high altitude airship. Finally, it has been proved by simulation that the attitude control system has desirable performance and the compound control scheme is feasible.%高空飞艇在上升和下降阶段时单独的空气舵控制或副气囊充放气操纵都难以实现飞艇的快速爬升和悬停的要求.针对高空飞艇纵的控制操纵特点,提出了采用副气囊充放气和空气舵组合控制的高空飞艇高度控制方案.当高度存在大误差时,采用副气囊和空气舵组合控制改变飞艇的姿态实现快速爬升或下降;当接近悬停高度时,主要采用副气囊充放气进行高度调整,从而实现高度的大范围控制.首先完成了采用组合控制的高空飞艇动力学建模;然后,基于最优控制对高空飞艇纵向高度控制系统进行了设计;最后给出了高空飞艇高度控制系统的仿真验证.结果表明所提出的高空飞艇组合控制方案是可行的.

  17. Superpressure Tow Balloon for Extending Durations and Modifying Trajectories of High Altitude Balloon Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed innovation involves the concept of using a Superpressure Tow Balloon (STB) with existing NASA high altitude balloon designs to form a tandem balloon...

  18. Changes in physical performance parameters during and after moderate altitude training in elite cross country skiers

    DEFF Research Database (Denmark)

    Jensen, Kurt; Höög, Martina; Willis, Sarah;

    2013-01-01

    INTRODUCTION: The Olympic cross country skiing competitions in 2014 will be held in Sochi, Russia at an altitude of approximately 1500m. Although moderate, this altitude is known to reduce performance in highly trained endurance athletes. It is also known that individuals react differently during...... altitude exposure. The purpose of this study was to evaluate performance changes during and after three weeks of training in moderate altitude in elite skiers. METHOD: Four male and three female skiers were tested on a roller skiing treadmill using the classic technique at sea level (NORM1), after 3 and 20...... and then grade every minute. Oxygen uptake (VO2) was measured continuously during submaximal and maximal exercise. Blood lactate concentrations were measured during the 1 min rest between submax stages and 2 min after the max test. Power at each submax and max stage were calculated from roller ski friction...

  19. A necklace of pearl in high altitude medicine and hypoxic physiology in Yushu Earthquake

    Institute of Scientific and Technical Information of China (English)

    Fan Ming

    2013-01-01

    During Yushu Earthquake,a large number of rescuers flocked to the mountainous quake areas.Under such a very specific circumstance,a high incidence of acute altitude illness was observed in rescuers who rapidly traveled from near sea level to an altitude of 4 000 m.It is evident that acute altitude illness leads to a significant human and economic toll,and also seriously influences the mountain rescue operation.So what does this teach us about mountain rescue in Yushu? Professor Wu Tianyi and many other authors collected shining points of the experiences and drew the lessons from the Yushu Earthquake into this special issue in Engineering Sciences which is like to thread pearl beads for a necklace.What readers learn from this special issue will have implications for the health and well-being of all high altitude populations all over the world.

  20. Altitude of the top of the Lower Hell Creek aquifer in the Williston structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the altitude, in feet above North American Vertical Datum of 1988 (NAVD88), of the Lower Hell Creek aquifer in the Williston structural basin....

  1. Altitude of the top of the Upper Hell Creek hydrogeologic unit in the Williston structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the altitude, in feet above North American Vertical Datum of 1988 (NAVD88), of the Upper Hell Creek hydrogeologic unit in the Williston...

  2. The relationship of body weight to altitude in preschool children of Southwestern Saudi Arabia

    Directory of Open Access Journals (Sweden)

    Mohammad-Elhabeeb M Khalid

    2007-01-01

    Conclusion : The findings of this study indicate that thinness is a major nutritional problem among lowland preschool children. This may be attributed to the prevailing tropical environmental conditions on the health of children at low altitude.

  3. Thermally Stable Catalytic Combustors for Very High Altitude Airbreathing Propulsion Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Aerospace vehicles operating at high altitudes have the potential to be less expensive and more versatile alternatives to space based systems for earth/space...

  4. Altitude of the top of the basal confining unit in the Powder River structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the altitude, in feet above North American Vertical Datum of 1988 (NAVD88), of the basal confining unit in the Powder River basin. The data are...

  5. Altitude of the top of the lower Fort Union aquifer in the Williston structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the altitude, in feet above North American Vertical Datum of 1988 (NAVD88), of the lower Fort Union aquifer in the Williston structural basin....

  6. Altitude of the top of the upper Fort Union aquifer in the Powder River structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the altitude, in feet above North American Vertical Datum of 1988 (NAVD88), of the upper Fort Union aquifer in the Powder River basin. The data...

  7. Altitude of the top of the upper Fort Union aquifer in the Williston structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the altitude, in feet above North American Vertical Datum of 1988 (NAVD88), of the upper Fort Union aquifer in the Williston structural basin....

  8. Altitude of the top of the lower Fort Union aquifer in the Powder River structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the altitude, in feet above North American Vertical Datum of 1988 (NAVD88), of the lower Fort Union aquifer in the Powder River basin. The data...

  9. Altitude of the top of the middle Fort Union hydrogeologic unit in the Williston structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the altitude, in feet above North American Vertical Datum of 1988 (NAVD88), of the middle Fort Union hydrogeologic unit in the Williston...

  10. Altitude of the top of the Fox Hills aquifer in the Williston structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the altitude, in feet above North American Vertical Datum of 1988 (NAVD88), of the Fox Hills aquifer in the Williston structural basin. The...

  11. Easy-to-Use UAV Ground Station Software for Low-Altitude Civil Operations Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to design and develop easy-to-use Ground Control Station (GCS) software for low-altitude civil Unmanned Aerial Vehicle (UAV) operations. The GCS software...

  12. Neutrons from thunderstorms at low atmospheric altitudes and related doses at aircraft

    International Nuclear Information System (INIS)

    We conduct a simulation of thunderstorm neutron flashes at the lowest atmospheric altitudes below 10 km. The neutron generation mechanism is based on the nowadays conventional idea of possibility for photonuclear reactions to proceed on the atmospheric components owing to TGF photons. Our modeling includes generation of neutrons from TGF and their further propagation with account of interaction with background nuclei. Using the calculation results we investigate the neutron flux properties with respect to problem of their registration, and predict the radiation environment caused by thunderstorm neutrons on altitudes of civil airflights. It is shown, that good conditions for the neutron flashes observation are provided from the 3 km altitude, and, possibly, the neutrons can be registered at ground level. We also found that thunderstorm-neutron-related effective dose can reach the value of 0.5 mSv in the region close to the TGF source if it is located at an altitude of 10 km.

  13. Altitudes of the top of model layers in the Central Valley Hydrologic Model (CVHM)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital dataset defines the model grid and altitudes of the top of the 10 model layers and base of the model simulated in the transient hydrologic model of the...

  14. Subclinical high altitude pulmonary edema:A clinical observation of 12 cases in Yushu

    Institute of Scientific and Technical Information of China (English)

    Li Shuzhi; Zheng Bihai; Wu Tianyi; Chen Huixing; Zhang Ming

    2013-01-01

    During the Yushu Earthquake on April 14,2010,a high incidence of acute high altitude illness was observed in the mountain rescuers,and 0.73 % of these patients suffered from high altitude pulmonary edema,of which 12 patients developed subclinical pulmonary edema and concomitantly contracted acute mountain sickness.Symptoms and signs were atypically high heart rate with high respiratory rate,striking cyanosis,and significantly low oxygen saturation,whereas no moist rates were heard on auscultation,and Chest X-ray showed peripheral with a patchy distribution of mottled infiltrations in one or both lung fields.We believe that subclinical high altitude pulmonary edema is an earliest stage of pulmonary edema at high altitude.The possible pathogenesis and the diagnosis were discussed.

  15. Is Pulse Oximetry Useful for Screening Neonates for Critical Congenital Heart Disease at High Altitudes?

    Science.gov (United States)

    Hoffman, Julien I E

    2016-06-01

    Now that pulse oximetry is used widely to screen for critical congenital heart disease, it is time to consider whether this screening method is applicable to those who live at high altitudes. Consideration of basic physical principles and reports from the literature indicate that not only is the 95 % cutoff point for arterial oxygen saturation incorrect at high altitudes, but the lower saturations are accompanied by greater variability and therefore there is the possibility of a greater percentage of false-positive screening tests at high altitudes. Because of ethnic differences in response to high altitudes, normative data will have to be collected separately in different countries and perhaps for different ethnic groups.

  16. Albuminuria and overall capillary permeability of albumin in acute altitude hypoxia

    DEFF Research Database (Denmark)

    Hansen, J M; Olsen, N V; Feldt-Rasmussen, B;

    1994-01-01

    groups. Exercise did not reveal any further renal dysfunction. In both groups, high altitude increased TERalb from 4.8 to > 6.7%/h (P < 0.05). In conclusion, acute altitude hypoxia increases Ualb despite unchanged tubular function and independent of effects of isradipine on filtration fraction. The......The mechanism of proteinuria at high altitude is unclear. Renal function and urinary excretion rate of albumin (Ualb) at rest and during submaximal exercise and transcapillary escape rate of 125I-labeled albumin (TERalb) were investigated in 12 normal volunteers at sea level and after rapid and...... passive ascent to 4,350 m. The calcium antagonist isradipine (5 mg/day; n = 6) or placebo (n = 6) was administered to abolish hypoxia-induced rises in blood pressure. Lithium clearance and urinary excretion of beta 2-microglobulin were used to evaluate renal tubular function. High altitude increased Ualb...

  17. Altitude of the bottom of the Trinidad Sandstone in the Raton Basin, Las Animas County, Colorado

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of structure contours that show lines of equal altitude of the bottom of the Trinidad Sandstone, the contact between the Trinidad Sandstone...

  18. Gas exchange and hatchability of chicken eggs incubated at simulated high altitude.

    Science.gov (United States)

    Visschedijk, A H

    1985-02-01

    Chicken eggs laid at sea level were incubated at sea level (control conditions), at a simulated altitude of 5.5 km without any further measures (natural conditions), and at a simulated altitude of 5.7 km at optimal incubator gas composition (optimal conditions). Under optimal conditions the incubator relative humidity was 70% throughout incubation, the gas mixture supplied to the incubator contained 45% O2-55% N2, and the ventilation rate was reduced to 6% of control in order to maintain the normal air-space gas tensions and to compensate for the increased eggshell conductance at altitude. The embryos that developed under control conditions showed a normal CO2 production with 94% hatchability of fertile eggs. Under natural conditions at altitude all embryos died within a few days. Optimal conditions resulted in an almost normal gas exchange and in an improvement of hatchability from 0 to 81% of fertile eggs.

  19. Altitude of the top of the basal confining unit in the Williston structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the altitude, in feet above North American Vertical Datum of 1988 (NAVD88), of the basal confining unit in the Williston structural basin. The...

  20. Computational mission analysis and conceptual system design for super low altitude satellite

    Institute of Scientific and Technical Information of China (English)

    Ming Xu; Jinlong Wang; Nan Zhou

    2014-01-01

    This paper deals with system engineering and design methodology for super low altitude satel ites in the view of the com-putational mission analysis. Due to the slight advance of imaging instruments, such as the focus of camera and the image element of charge coupled device (CCD), it is an innovative and economical way to improve the camera’s resolution to enforce the satel ite to fly on the lower altitude orbit. DFH-3, the mature satel ite bus de-veloped by Chinese Academy of Space Technology, is employed to define the mass and power budgets for the computational mis-sion analysis and the detailed engineering design for super low altitude satel ites. An effective iterative algorithm is proposed to solve the ergodic representation of feasible mass and power bud-gets at the flight altitude under constraints. Besides, boundaries of mass or power exist for every altitude, where the upper boundary is derived from the maximum power, while the minimum thrust force holds the lower boundary before the power reaching the initial value. What’s more, an analytical algorithm is employed to numerical y investigate the coverage percentage over the altitude, so that the nominal altitude could be selected from al the feasi-ble altitudes based on both the mass and power budgets and the repetitive ground traces. The local time at the descending node is chosen for the nominal sun-synchronous orbit based on the average evaluation function. After determining the key orbital ele-ments based on the computational mission analysis, the detailed engineering design on the configuration and other subsystems, like power, telemetry telecontrol and communication (TT&C), and attitude determination and control system (ADCS), is performed based on the benchmark bus, besides, some improvements to the bus are also implemented to accommodate the flight at a super low altitude. Two operation strategies, drag-free closed-loop mode and on/off open-loop mode, are presented to maintain the satel

  1. Reconciling high-altitude precipitation in the upper Indus basin with glacier mass balances and runoff

    OpenAIRE

    Immerzeel, W. W.; N. Wanders; A. F. Lutz; J. M. Shea; M. F. P. Bierkens

    2015-01-01

    Mountain ranges in Asia are important water suppliers, especially if downstream climates are arid, water demands are high and glaciers are abundant. In such basins, the hydrological cycle depends heavily on high-altitude precipitation. Yet direct observations of high-altitude precipitation are lacking and satellite derived products are of insufficient resolution and quality to capture spatial variation and magnitude of mountain precipitation. Here we use glacier mass balances t...

  2. Phenotypic Plasticity of the Lung Surfactant System at High Altitude in Deer Mice, Peromyscus maniculatus

    OpenAIRE

    Diaz, Sonia

    2012-01-01

    The pulmonary surfactant system is a multifaceted and highly complex mixture of lipids and proteins that work to reduce the surface tension created at the air-liquid interface within the lung, and provide innate immunity to the lung. Reducing surface tension allows for lung stability, patency and functioning, a crucial task to undertake in oxygen-limiting environments, such as high altitude. The lower partial pressures of oxygen and colder ambient temperatures found at high altitude pose a ...

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

    OpenAIRE

    Gaurav Sikri, Gaurav

    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...

  4. 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.

  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. RESEARCH ON THE KEY TECHNOLOGY OF LARGE SCALE MAPPING FROM LOW ALTITUDE PHOTOGRAMMETRY

    OpenAIRE

    Bo-Yi, Wu; Ning, Zhang; Guo-Zhong, Su

    2016-01-01

    Based on the theoretic analysis of the accuracy in large scale photogrammetric mapping, some defects in traditional procedure were discussed. A set of key technologies dedicate to accuracy improvement in low altitude photogrammetry were analyzed in detail, namely the utilization of wide angle camera and low altitude flight, enhancement in image matching, predesigned layout of Ground Control Points (GCPs) in field survey, optimization of adjustment model and improvement in map processing. Besi...

  7. Precision Agriculture: Using Low-Cost Systems to Acquire Low-Altitude Images.

    Science.gov (United States)

    Ponti, Moacir; Chaves, Arthur A; Jorge, Fabio R; Costa, Gabriel B P; Colturato, Adimara; Branco, Kalinka R L J C

    2016-01-01

    Low cost remote sensing imagery has the potential to make precision farming feasible in developing countries. In this article, the authors describe image acquisition from eucalyptus, bean, and sugarcane crops acquired by low-cost and low-altitude systems. They use different approaches to handle low-altitude images in both the RGB and NIR (near-infrared) bands to estimate and quantify plantation areas. PMID:27514030

  8. The identification of major component of temu kunci (Kaemferia pandurata Roxb.) essential oils on different altitude

    OpenAIRE

    RETNA BANDRIATI ARNIPUTRI; AMALIA TETRANI SAKYA; MUJI RAHAYU

    2007-01-01

    The aims of this study was to know the major component of essential oils of Temu Kunci (Kaemferia pandurata Roxb.) on a different altitude. This research was carried out by method of Stahl destilation at BPTO and GCMS Cromatography at FMIPA UGM for both of from Kerjo (350 m asl) and Jumapolo (450 m asl). The difference of altitude of temu kunci’s lives on, the same of major component of essential oil but the content among them was different.

  9. From Doktor Kurowski's Schneegrenze to our modern glacier equilibrium line altitude (ELA)

    OpenAIRE

    R. J. Braithwaite

    2015-01-01

    Translated into modern terminology, Kurowski suggested in 1891 that the equilibrium line altitude (ELA) of a glacier is equal to the mean altitude of the glacier when the whole glacier is in balance between accumulation and ablation. Kurowski's method has been widely misunderstood, partly due to inappropriate use of statistical terminology by later workers, and has been little tested except by Braithwaite and Müller in a 1980 paper (for 32...

  10. From Doktor Kurowski's Schneegrenze to our modern glacier equilibrium line altitude (ELA)

    OpenAIRE

    R. J. Braithwaite

    2015-01-01

    Translated into modern terminology, Kurowski suggested in 1891 that the equilibrium line altitude (ELA) of a glacier is equal to the mean altitude of the glacier when the whole glacier is in balance between accumulation and ablation. Kurowski's method has been widely misunderstood, partly due to inappropriate use of statistical terminology by later workers, and has only been tested by Braithwaite and Müller in a 1980 paper (for 32 glaciers). I now compare Kurowski's mean alt...

  11. Image Positioning Accuracy Analysis for the Super Low Altitude Remote Sensing Satellite

    OpenAIRE

    Ming Xu; Nan Zhou

    2012-01-01

    Super low altitude remote sensing satellites maintain lower flight altitudes by means of ion propulsion in order to improve image resolution and positioning accuracy. The use of engineering data in design for achieving image positioning accuracy is discussed in this paper based on the principles of the photogrammetry theory. The exact line‐of‐sight rebuilding of each detection element and this direction precisely intersecting with the Earth’s elliptical when the camera on the satellite is ima...

  12. Adaptation of the Long-Lived Monocarpic Perennial Saxifraga longifolia to High Altitude1[OPEN

    Science.gov (United States)

    Morales, Melanie; Fleta-Soriano, Eva; Garcia, Maria B.

    2016-01-01

    Global change is exerting a major effect on plant communities, altering their potential capacity for adaptation. Here, we aimed at unveiling mechanisms of adaptation to high altitude in an endemic long-lived monocarpic, Saxifraga longifolia, by combining demographic and physiological approaches. Plants from three altitudes (570, 1100, and 2100 m above sea level [a.s.l.]) were investigated in terms of leaf water and pigment contents, and activation of stress defense mechanisms. The influence of plant size on physiological performance and mortality was also investigated. Levels of photoprotective molecules (α-tocopherol, carotenoids, and anthocyanins) increased in response to high altitude (1100 relative to 570 m a.s.l.), which was paralleled by reduced soil and leaf water contents and increased ABA levels. The more demanding effect of high altitude on photoprotection was, however, partly abolished at very high altitudes (2100 m a.s.l.) due to improved soil water contents, with the exception of α-tocopherol accumulation. α-Tocopherol levels increased progressively at increasing altitudes, which paralleled with reductions in lipid peroxidation, thus suggesting plants from the highest altitude effectively withstood high light stress. Furthermore, mortality of juveniles was highest at the intermediate population, suggesting that drought stress was the main environmental driver of mortality of juveniles in this rocky plant species. Population structure and vital rates in the high population evidenced lower recruitment and mortality in juveniles, activation of clonal growth, and absence of plant size-dependent mortality. We conclude that, despite S. longifolia has evolved complex mechanisms of adaptation to altitude at the cellular, whole-plant and population levels, drought events may drive increased mortality in the framework of global change. PMID:27440756

  13. The effect of altitude and intensity of physical activity on the exergy efficiency of respiratory system

    OpenAIRE

    Henriques, Izabela Batista; Mady, Carlos Eduardo Keutenedjian; Albuquerque Neto, Cyro; Yanagihara, Jurandir Itizo; Oliveira Junior, Silvio

    2014-01-01

    The effect of altitude on exercise performance of lowlanders has long been discussed, but it is still unclear whether the performance reduction is related to inefficiency of the respiratory system, body tissues or both. In the present work, exergy analysis was applied to the human body in order to compare its exergy efficiency under basal conditions and during physical activity at sea level and high altitudes for different periods of acclimatization. Two control volumes were analyzed: respira...

  14. A Novel Approach to Critical Congenital Heart Disease (CCHD Screening at Moderate Altitude

    Directory of Open Access Journals (Sweden)

    Erin Lueth

    2016-07-01

    Full Text Available The American Academy of Pediatrics (AAP has endorsed Critical Congenital Heart Disease (CCHD screening using pulse oximetry nationwide, but, however, acknowledges that altitude may impact failure rates and alternative algorithms may be required at high altitudes. We therefore evaluated a modified screening protocol at an altitude of 6200 feet with the hypothesis that modifications could decrease failure rates. We evaluated 2001 well, newborn infants ≥35 weeks gestation using a modified protocol, which included a lower saturation cutoff for the first screen (85% instead of the AAP recommended 90% and an oxygen hood intervention between the first two screens. Using our modified screening algorithm, we found a 0.3% failure rate, which was similar to the 0.2% sea-level rate and statistically different from the 1.1% rate identified in a recent study at similar altitude. Had the AAP protocol been used, the failure rate would have increased to 0.8%, which is similar to prior reports near this altitude. Echocardiograms were performed on failing newborns with no CCHD identified. A Birth Defects Registry Database review demonstrated one newborn with CCHD was missed after meeting AAP passing criteria. Overall, this study demonstrates that an alternative algorithm can be implemented at moderate altitude with decreased failure rate and comparable false negative rate.

  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. A GIS-aided response model of high-altitude permafrost to global change

    Institute of Scientific and Technical Information of China (English)

    李新; 程国栋

    1999-01-01

    Two models are used to simulate the high-altitude permafrost distribution on the Qinghai-Xizang Plateau. The two models are the "altitude model", a Gaussian distribution function used to describe the latitudinal zonation of permafrost based on the three-dimensional rules of high-altitude permafrost, and the "frost number model", a dimensionless ratio defined by manipulation of freezing and thawing degree-day sums. The results show that the "altitude model" can simulate the high-altitude permafrost distribution under present climate conditions accurately. Given the essential hypotheses and using the GCM scenarios from HADCM2, the "altitude model" is used for predicting the permafrost distribution change on the Qinghai-Xizang Plateau. The results show that the permafrost on the plateau will not change significantly during 20—50 a, the percentage of the total disappeared area will not be over 19%. However, by the year 2099, if the air temperature increases by an average of 2.91℃ on the plateau, the decre

  17. Lichen-Associated Fungal Community in Hypogymnia hypotrypa (Parmeliaceae, Ascomycota) Affected by Geographic Distribution and Altitude.

    Science.gov (United States)

    Wang, Yanyan; Zheng, Yong; Wang, Xinyu; Wei, Xinli; Wei, Jiangchun

    2016-01-01

    Lichen-associated fungal species have already been investigated in almost all the main growth forms of lichens, however, whether or not they are homogeneous and constant within each lichen species are still inconclusive. Moreover, the related ecological factors to affect and structure the fungal composition have been poorly studied. In order to answer these questions, we took Hypogymnia hypotrypa as a model to study the relationship between the lichen-associated fungal composition and two ecological factors, i.e., site and altitude, using the method of IlluminaMiSeq sequencing. Four different sites and two levels of altitude were included in this study, and the effects of site and altitude on fungal community composition were assessed at three levels, i.e., operational taxonomic unit (OTU), class and phylum. The results showed that a total of 50 OTUs were identified and distributed in 4 phyla, 13 classes, and 20 orders. The lichen-associated fungal composition within H. hypotrypa were significantly affected by both site and altitude at OTU and class levels, while at the phylum level, it was only affected by altitude. While the lichen associated fungal communities were reported to be similar with endophytic fungi of the moss, our results indicated the opposite results in some degree. But whether there exist specific OTUs within this lichen species corresponding to different sites and altitudes is still open. More lichen species and ecological factors would be taken into the integrated analyses to address these knowledge gaps in the near future. PMID:27547204

  18. Improvement in 100-m Sprint Performance at an Altitude of 2250 m

    Directory of Open Access Journals (Sweden)

    Nicholas P. Linthorne

    2016-05-01

    Full Text Available A fair system of recognizing records in athletics should consider the influence of environmental conditions on performance. The aim of this study was to determine the effect of an altitude of 2250 m on the time for a 100-m sprint. Competition results from the 13 Olympic Games between 1964 and 2012 were corrected for the effects of wind and de-trended for the historical improvement in performance. The time advantage due to competing at an altitude of 2250 m was calculated from the difference between the mean race time at the 1968 Olympic Games in Mexico City and the mean race times at the low-altitude competition venues. The observed time advantage of Mexico City was 0.19 (±0.02 s for men and 0.21 (±0.05 s for women (±90% confidence interval. These results indicate that 100-m sprinters derive a substantial performance advantage when competing at a high-altitude venue and that an altitude of 1000 m provides an advantage equivalent to a 2 m/s assisting wind (0.10 s. Therefore, the altitude of the competition venue as well as the wind speed during the race should be considered when recognizing record performances.

  19. Lichen-Associated Fungal Community in Hypogymnia hypotrypa (Parmeliaceae, Ascomycota) Affected by Geographic Distribution and Altitude

    Science.gov (United States)

    Wang, Yanyan; Zheng, Yong; Wang, Xinyu; Wei, Xinli; Wei, Jiangchun

    2016-01-01

    Lichen-associated fungal species have already been investigated in almost all the main growth forms of lichens, however, whether or not they are homogeneous and constant within each lichen species are still inconclusive. Moreover, the related ecological factors to affect and structure the fungal composition have been poorly studied. In order to answer these questions, we took Hypogymnia hypotrypa as a model to study the relationship between the lichen-associated fungal composition and two ecological factors, i.e., site and altitude, using the method of IlluminaMiSeq sequencing. Four different sites and two levels of altitude were included in this study, and the effects of site and altitude on fungal community composition were assessed at three levels, i.e., operational taxonomic unit (OTU), class and phylum. The results showed that a total of 50 OTUs were identified and distributed in 4 phyla, 13 classes, and 20 orders. The lichen-associated fungal composition within H. hypotrypa were significantly affected by both site and altitude at OTU and class levels, while at the phylum level, it was only affected by altitude. While the lichen associated fungal communities were reported to be similar with endophytic fungi of the moss, our results indicated the opposite results in some degree. But whether there exist specific OTUs within this lichen species corresponding to different sites and altitudes is still open. More lichen species and ecological factors would be taken into the integrated analyses to address these knowledge gaps in the near future. PMID:27547204

  20. Effect of altitude and season on microbial activity, abundance and community structure in Alpine forest soils.

    Science.gov (United States)

    Siles, José A; Cajthaml, Tomas; Minerbi, Stefano; Margesin, Rosa

    2016-03-01

    In the current context of climate change, the study of microbial communities along altitudinal gradients is especially useful. Only few studies considered altitude and season at the same time. We characterized four forest sites located in the Italian Alps, along an altitude gradient (545-2000 m a.s.l.), to evaluate the effect of altitude in spring and autumn on soil microbial properties. Each site in each season was characterized with regard to soil temperature, physicochemical properties, microbial activities (respiration, enzymes), community level physiological profiles (CLPP), microbial abundance and community structure (PLFA). Increased levels of soil organic matter (SOM) and nutrients were found at higher altitudes and in autumn, resulting in a significant increase of (soil dry-mass related) microbial activities and abundance at higher altitudes. Significant site- and season-specific effects were found for enzyme production. The significant interaction of the factors site and incubation temperature for soil microbial activities indicated differences in microbial communities and their responses to temperature among sites. CLPP revealed site-specific effects. Microbial community structure was influenced by altitudinal, seasonal and/or site-specific effects. Correlations demonstrated that altitude, and not season, was the main factor determining the changes in abiotic and biotic characteristics at the sites investigated. PMID:26787774

  1. Effect of altitude relocations upon AaDo2 at rest and during exercise.

    Science.gov (United States)

    Cruz, J C; Hartley, L H; Vogel, J A

    1975-09-01

    The supine pulmonary venous admixture (shunt) has been measured at Cerro de Pasco, 4,350 m altitude in eight subjects native to high altitude (HAN) under resting condition. Alveolar-arterial O2 tension difference (AaDO2) was also determined at rest and during exercise. The same subjects were studied again after 10 days' sojourn at sea level in Lima at 150 m altitude. They were compared with four subjects from sea level (SLN) who were studied first at Lima and after 2 and 10 days at Cerro de Pasco. At altitude, AaDO2 was smaller in HAN than SLN both at rest and during exercise. Shunt was the same in both groups. It is concluded that HAN show more even ventilation/perfusion relationship (VA/Q) at altitude, probably due to their high pulmonary artery pressure. On the contrary, SLN show less even VA/Q on altitude exposure, since their shunt decreased 37%. At sea level, HAN increased their AaDO2 due partially to an increase of 110% in their shunt, and in part due to less even VA/Q as shown by augmented VD/VT ratios. Each group tended to have a more effective gas exchange in its own environment.

  2. Effect of high altitude exposure on spermatogenesis and epididymal sperm count in male rats.

    Science.gov (United States)

    Gasco, M; Rubio, J; Chung, A; Villegas, L; Gonzales, G F

    2003-12-01

    The present study was designed to determine the effect of exposure to high altitude on spermatogenesis using transillumination technique and sperm count in male rats. In addition, the effect of oral intubation for intragastric administration of vehicle on testicular parameters in adult male rats in a schedule of 42 days was assessed. Male rats were exposed to Cerro de Pasco (Peru) at 4340 m for 3, 7, 14, 21, 28, 35 and 42 days resulting in a modification of the pattern of the seminiferous tubule stages. At day 3, stages I, IV-V, VI, VII and IX-XI were relatively shorter at high altitude than at sea level. At day 7, stages VIII, IX-XI, XII and XIII-XIV were reduced. At day 14, stages VII, VIII and IX-XI were reduced. At day 21 and 28, stages VIII, XII and XIII-XIV were significantly increased at high altitude. At day 35 an increase in stage XIII-XIV was observed. At day 42, stages II-III, IX-XI and XII were significantly increased at high altitude. Epididymal sperm count was significantly reduced at day 7 of exposure to high altitude and maintained low levels with respect to sea level up to 42 days. In conclusion, high altitude exposure affects spermatogenesis, particularly onset of mitosis and spermiation. This in turn affects epididymal sperm count.

  3. The Gravity Field of Mercury After the Messenger Low-Altitude Campaign

    Science.gov (United States)

    Mazarico, Erwan; Genova, Antonio; Goossens, Sander; Lemoine, Frank G.; Smith, David E.; Zuber, Maria T.; Neumann, Gary A.; Solomon, Sean C.

    2015-01-01

    The final year of the MESSENGER mission was designed to take advantage of the remaining propellant onboard to provide a series of lowaltitude observation campaigns and acquire novel scientific data about the innermost planet. The lower periapsis altitude greatly enhances the sensitivity to the short-wavelength gravity field, but only when the spacecraft is in view of Earth. After more than 3 years in orbit around Mercury, the MESSENGER spacecraft was tracked for the first time below 200-km altitude on 5 May 2014 by the NASA Deep Space Network (DSN). Between August and October, periapsis passages down to 25-km altitude were routinely tracked. These periods considerably improved the quality of the data coverage. Before the end of its mission, MESSENGER will fly at very low altitudes for extended periods of time. Given the orbital geometry, however the periapses will not be visible from Earth and so no new tracking data will be available for altitudes lower than 75 km. Nevertheless, the continuous tracking of MESSENGER in the northern hemisphere will help improve the uniformity of the spatial coverage at altitudes lower than 150 km, which will further improve the overall quality of the Mercury gravity field.

  4. Monocular Vision System for Fixed Altitude Flight of Unmanned Aerial Vehicles.

    Science.gov (United States)

    Huang, Kuo-Lung; Chiu, Chung-Cheng; Chiu, Sheng-Yi; Teng, Yao-Jen; Hao, Shu-Sheng

    2015-01-01

    The fastest and most economical method of acquiring terrain images is aerial photography. The use of unmanned aerial vehicles (UAVs) has been investigated for this task. However, UAVs present a range of challenges such as flight altitude maintenance. This paper reports a method that combines skyline detection with a stereo vision algorithm to enable the flight altitude of UAVs to be maintained. A monocular camera is mounted on the downside of the aircraft's nose to collect continuous ground images, and the relative altitude is obtained via a stereo vision algorithm from the velocity of the UAV. Image detection is used to obtain terrain images, and to measure the relative altitude from the ground to the UAV. The UAV flight system can be set to fly at a fixed and relatively low altitude to obtain the same resolution of ground images. A forward-looking camera is mounted on the upside of the aircraft's nose. In combination with the skyline detection algorithm, this helps the aircraft to maintain a stable flight pattern. Experimental results show that the proposed system enables UAVs to obtain terrain images at constant resolution, and to detect the relative altitude along the flight path. PMID:26184213

  5. Monocular Vision System for Fixed Altitude Flight of Unmanned Aerial Vehicles

    Directory of Open Access Journals (Sweden)

    Kuo-Lung Huang

    2015-07-01

    Full Text Available The fastest and most economical method of acquiring terrain images is aerial photography. The use of unmanned aerial vehicles (UAVs has been investigated for this task. However, UAVs present a range of challenges such as flight altitude maintenance. This paper reports a method that combines skyline detection with a stereo vision algorithm to enable the flight altitude of UAVs to be maintained. A monocular camera is mounted on the downside of the aircraft’s nose to collect continuous ground images, and the relative altitude is obtained via a stereo vision algorithm from the velocity of the UAV. Image detection is used to obtain terrain images, and to measure the relative altitude from the ground to the UAV. The UAV flight system can be set to fly at a fixed and relatively low altitude to obtain the same resolution of ground images. A forward-looking camera is mounted on the upside of the aircraft’s nose. In combination with the skyline detection algorithm, this helps the aircraft to maintain a stable flight pattern. Experimental results show that the proposed system enables UAVs to obtain terrain images at constant resolution, and to detect the relative altitude along the flight path.

  6. Changes in maximal double poling performance during and after moderate altitude training in elite cross country skiers

    DEFF Research Database (Denmark)

    Höög, Martina; Jensen, Kurt; Willis, Sarah;

    2013-01-01

    INTRODUCTION: In 2014, the Olympic cross-country ski competitions will be held in Sochi, Russia at approximately 1500m altitude. Even moderate altitude can have negative effects on performance in highly trained endurance athletes and individuals may adapt and react differently to altitude exposure...... [1]. Different skiing techniques (such as double poling) may also be affected by altitude due to the involvement of the upper body. Thus, the purpose of our study was to evaluate changes in double poling performance during and after three weeks of training in moderate altitude in elite skiers. METHOD......: Four male and three female skiers were tested on a roller skiing treadmill using the double poling technique at sea level (NORM1), after 3 and 20 days at 1500m altitude (ALT1 and ALT2), and 10 days after altitude at sea level (NORM2). A progressive “all out” double pooling test consisted of 4-7 min...

  7. ROCK2 and MYLK variants under hypobaric hypoxic environment of high altitude associate with high altitude pulmonary edema and adaptation

    Science.gov (United States)

    Pandey, Priyanka; Mohammad, Ghulam; Singh, Yogendra; Qadar Pasha, MA

    2015-01-01

    Objective To date, a major class of kinases, serine–threonine kinase, has been scantly investigated in stress-induced rare, fatal (if not treated early), and morbid disorder, high altitude pulmonary edema (HAPE). This study examined three major serine–threonine kinases, ROCK2, MYLK, and JNK1, along with six other genes, tyrosine hydroxylase, G-protein subunits GNA11 and GNB3, and alpha1 adrenergic receptor isoforms 1A, 1B, and 1D as candidate gene markers of HAPE and adaptation. Methods For this, 57 variants across these nine genes were genotyped in HAPE patients (n=225), HAPE controls (n=210), and highlanders (n=259) by Sequenom MS (TOF)-based MassARRAY® platform using iPLEX™ Gold technology. In addition, to study the gene expression, quantitative real-time polymerase chain reaction was performed in human peripheral blood mononuclear cells of the three study groups. Results A significant association was observed for C allele (ROCK2 single-nucleotide polymorphism, rs10929728) with HAPE (P=0.03) and C, T, and A alleles (MYLK single-nucleotide polymorphisms, rs11717814, rs40305, and rs820336) with both HAPE and adaptation (P=0.001, P=0.006, and P=0.02, respectively). ROCK2 88 kb GGGTTGGT haplotype was associated with lower risk of HAPE (P=0.0009). MYLK 7 kb haplotype CTA, composed of variant alleles, was associated with higher risk of HAPE (P=0.0006) and lower association with adaptation (P=1E–06), whereas haplotype GCG, composed of wild-type alleles, was associated with lower risk of HAPE (P=0.001) and higher association with adaptation (P=1E–06). Haplotype–haplotype and gene–gene interactions demonstrated a correlation in working of ROCK2 and MYLK. Conclusion The data suggest the association of ROCK2 with HAPE and MYLK with HAPE and adaptation in Indian population. The outcome has provided new insights into the physiology of HAPE and adaptation. PMID:26586960

  8. Bovine fasciolosis at increasing altitudes: Parasitological and malacological sampling on the slopes of Mount Elgon, Uganda

    Directory of Open Access Journals (Sweden)

    Howell Alison

    2012-09-01

    Full Text Available Abstract Background To clarify the extent and putative transmission zone of bovine fasciolosis on the slopes of Mount Elgon, Uganda, conjoint parasitological and malacological surveys, inclusive of inspection of animals at slaughter, were undertaken at increasing altitudes. Results A total of 239 cattle were sampled across eight locations ranging in elevation from 1112-2072 m. Faecal material was examined for presence of Fasciola eggs and sera were tested by ELISA for antibodies against Fasciola antigens. Bolstering this, 38 cattle at slaughter from 2 abattoir sites at 1150 m and 1947 m were inspected; in addition, wild buffalo stool (n = 10 opportunistically picked within Mount Elgon National Park (MENP at 3640 m was examined. By faecal egg detection, prevalence of Fasciola gigantica at low (1500 m altitude sites was 43.7% (95% CI 35.4-52.2 and 1.1% (95% CI 0.0-6.0, respectively, while by ELISA was much higher, low altitude - 77.9% (95% CI 69.7-85.4 and high altitude - 64.5% (95% CI 51.3-76.3. The decline in prevalence with increasing altitude was corroborated by abattoir sampling. Thirty seven aquatic habitats, ranging from 1139-3937 m in altitude were inspected for freshwater snails, 12 of which were within MENP. At lower altitudes, Lymnaea (Radix natalensis was common, and often abundant, but at higher altitudes became much rarer ceasing to be found above 1800 m. On the other hand, Lymnaea (Galba truncatula was found only at altitudes above 3000 m and within MENP alone. The snail identifications were confirmed by DNA analysis of the ribosomal 18S gene. Conclusions Active infections of F. gigantica in cattle are common in lower altitude settings but appear to diminish with increasing elevation. This is likely due to a growing paucity of intermediate hosts, specifically populations of L. natalensis for which a natural boundary of 1800 m appeared. Although F. hepatica was not encountered, the presence of several

  9. Analysis of the variation of the 0°C isothermal altitude during rainfall events

    Science.gov (United States)

    Zeimetz, Fränz; Garcìa, Javier; Schaefli, Bettina; Schleiss, Anton J.

    2016-04-01

    In numerous countries of the world (USA, Canada, Sweden, Switzerland,…), the dam safety verifications for extreme floods are realized by referring to the so called Probable Maximum Flood (PMF). According to the World Meteorological Organization (WMO), this PMF is determined based on the PMP (Probable Maximum Precipitation). The PMF estimation is performed with a hydrological simulation model by routing the PMP. The PMP-PMF simulation is normally event based; therefore, if no further information is known, the simulation needs assumptions concerning the initial soil conditions such as saturation or snow cover. In addition, temperature series are also of interest for the PMP-PMF simulations. Temperature values can not only be deduced from temperature measurement but also using the temperature gradient method, the 0°C isothermal altitude can lead to temperature estimations on the ground. For practitioners, the usage of the isothermal altitude for referring to temperature is convenient and simpler because one value can give information over a large region under the assumption of a certain temperature gradient. The analysis of the evolution of the 0°C isothermal altitude during rainfall events is aimed here and based on meteorological soundings from the two sounding stations Payerne (CH) and Milan (I). Furthermore, hourly rainfall and temperature data are available from 110 pluviometers spread over the Swiss territory. The analysis of the evolution of the 0°C isothermal altitude is undertaken for different precipitation durations based on the meteorological measurements mentioned above. The results show that on average, the isothermal altitude tends to decrease during the rainfall events and that a correlation between the duration of the altitude loss and the duration of the rainfall exists. A significant difference in altitude loss is appearing when the soundings from Payerne and Milan are compared.

  10. Variation in airborne 137Cs peak levels with altitude from high-altitude locations across Europe after the arrival of Fukushima-labeled air masses

    Science.gov (United States)

    Masson, Olivier; Bieringer, Jacqueline; Dalheimer, Axel; Estier, Sybille; Evrard, Olivier; Penev, Ilia; Ringer, Wolfgang; Schlosser, Clemens; Steinkopff, Thomas; Tositti, Laura; de Vismes-Ott, Anne

    2015-04-01

    During the Fukushima Daiichi nuclear power plant (FDNPP) accident, a dozen of high-altitude aerosol sampling stations, located between 850 and 3,454 m above sea level (a.s.l.), provided airborne activity levels across Europe (Fig. 1). This represents at most 5% of the total number of aerosol sampling locations that delivered airborne activity levels (at least one result) in Europe, in connection with this nuclear accident. High altitude stations are typically equipped with a high volume sampler that collects aerosols on filters. The Fukushima-labeled air mass arrival and the peak of airborne cesium-137 (137Cs) activity levels were registered in Europe at different dates depending on the location, with differences up to a factor of six on a regional scale. Besides this statement related to lowland areas, we have compared the maximum airborne levels registered at high-altitude European locations (850 m dynamic of air movements at such high altitudes. After the 137Cs peak value, the plume concentration decreased whatever the 7Be level. Due to the cosmogenic origin of 7Be, its increase in the ground-level air is usually associated with downwind air movements, i.e. stratospheric air intrusions or at least air from high-tropospheric levels, into lower atmospheric layers. This means that Fukushima-labeled air masses registered at ground level were transported until Europe at rather high altitudes. This is consistent with 137Cs activity levels and 133Xe observations performed at the tropopause level thanks to aircraft samples over Germany and Switzerland (Estier and Steinmann). This also validates dispersion model computation according to which the Fukushima-labeled air masses were transported to Europe above 5500 m a.s.l. Conclusions : High altitude locations are on 'sentry duty' for radioactive monitoring and cross-border spreading of a contaminated plume. In this sense they can provide useful information on the vertical spreading of radionuclides, reveal arrival times

  11. 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%

  12. Macroscopic time and altitude distribution of plasma turbulence induced in ionospheric modification experiments

    Energy Technology Data Exchange (ETDEWEB)

    Rose, H.; Dubois, D.; Russell, D. [Lodestar Research Corp., Boulder, CO (United States); Hanssen, A. [Univ. of Tromsoe (Norway)

    1996-03-01

    This is the final report of a three-year Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). This research concentrated on the time dependence of the heater, induced-turbulence, and electron-density profiles excited in the ionosphere by a powerful radio-frequency heater wave. The macroscopic density is driven by the ponderomotive pressure and the density self-consistently determines the heater propagation. For typical parameters of the current Arecibo heater, a dramatic quasi-periodic behavior was found. For about 50 ms after turn-on of the heater wave, the turbulence is concentrated at the first standing-wave maximum of the heater near reflection altitude. From 50--100 ms the standing-wave pattern drops by about 1--2 km in altitude and the quasi-periodicity reappears at the higher altitudes with a period of roughly 50 ms. This behavior is due to the half-wavelength density depletion grating that is set up by the ponderomotive pressure at the maxima of the heater standing-wave pattern. Once the grating is established the heater can no longer propagate to higher altitudes. The grating is then unsupported by the heater at these altitudes and decays, allowing the heater to propagate again and initiate another cycle. For stronger heater powers, corresponding to the Arecibo upgrade and the HAARP heater now under construction, the effects are much more dramatic.

  13. Macroscopic time and altitude distribution of plasma turbulence induced in ionospheric modification experiments

    International Nuclear Information System (INIS)

    This is the final report of a three-year Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). This research concentrated on the time dependence of the heater, induced-turbulence, and electron-density profiles excited in the ionosphere by a powerful radio-frequency heater wave. The macroscopic density is driven by the ponderomotive pressure and the density self-consistently determines the heater propagation. For typical parameters of the current Arecibo heater, a dramatic quasi-periodic behavior was found. For about 50 ms after turn-on of the heater wave, the turbulence is concentrated at the first standing-wave maximum of the heater near reflection altitude. From 50--100 ms the standing-wave pattern drops by about 1--2 km in altitude and the quasi-periodicity reappears at the higher altitudes with a period of roughly 50 ms. This behavior is due to the half-wavelength density depletion grating that is set up by the ponderomotive pressure at the maxima of the heater standing-wave pattern. Once the grating is established the heater can no longer propagate to higher altitudes. The grating is then unsupported by the heater at these altitudes and decays, allowing the heater to propagate again and initiate another cycle. For stronger heater powers, corresponding to the Arecibo upgrade and the HAARP heater now under construction, the effects are much more dramatic

  14. Reconciling high-altitude precipitation in the upper Indus basin with glacier mass balances and runoff

    Science.gov (United States)

    Immerzeel, Walter; Wanders, Niko; Lutz, Arthur; Shea, Joseph; Bierkens, Marc

    2016-04-01

    Mountain ranges in Asia are important water suppliers, especially if downstream climates are arid, water demands are high and glaciers are abundant. In such basins, the hydrological cycle depends heavily on high-altitude precipitation. Yet direct observations of high-altitude precipitation are lacking and satellite derived products are of insufficient resolution and quality to capture spatial variation and magnitude of mountain precipitation. Here we use glacier mass balances to inversely infer the high-altitude precipitation in the upper Indus basin and show that the amount of precipitation required to sustain the observed mass balances of large glacier systems is far beyond what is observed at valley stations or estimated by gridded precipitation products. An independent validation with observed river flow confirms that the water balance can indeed only be closed when the high altitude precipitation on average is more than twice as high and in extreme cases up to a factor of 10 higher than previously thought. We conclude that these findings alter the present understanding of high-altitude hydrology and will have an important bearing on climate change impact studies, planning and design of hydropower plants and irrigation reservoirs as well as the regional geopolitical situation in general.

  15. Airborne reconnaissance in the civilian sector - Agricultural monitoring from high-altitude powered platforms

    Science.gov (United States)

    Youngblood, J. W.; Jackson, R. D.

    1983-01-01

    Design concepts and mission applications for unmanned high-altitude powered platforms (HAPPs) are discussed. A chemically powered HAPP (operating altitude 18-21 km, wingspan 26 m, payload 91 kg, endurance 2-3 days) would use current turboprop technology. A microwave-powered HAPP (operating altitude around 21 km, wingspan 57.9 m, payload 500 kg, endurance weeks or months) would circle within or perform boost-glide maneuvers around a microwave beam of density 1.1 kw/sq m. Of two solar-powered-HAPP designs presented, the more promising uses five vertical solar-panel-bearing fins, two of which can be made horizontal at night, (wingspan 57.8/98.3 m, payload 113 kg, endurance weeks or months). The operating altitude depends on the latitude and season: this HAPP design is shown to be capable of year-round 20-km-altitude flights over the San Joaquin Valley in California, where an agricultural-monitoring mission using Landsat-like remote sensors is proposed. Other applications may be better served by the characteristics of the other HAPPs. The primary advantage of HAPPs over satellites is found to be their ability to provide rapidly available high-resolution continuous or repetitive coverage of specific areas at relatively low cost.

  16. Simulation development of a forward sensor-enhanced low-altitude guidance system

    Science.gov (United States)

    Zelenka, Richard E.; Swenson, Harry N.; Dearing, Munro G.; Hardy, Gordon H.

    1993-01-01

    The requirement to operate aircraft at low-altitude near the terrain is common in the military community and essential for helicopters. The risk and crew workload in this flight regime is severe, with navigation, guidance, and obstacle avoidance demanding high attention. A guidance system relying on digitized terrain elevation maps has been developed that employs airborne navigation, mission requirements, aircraft performance limits, and radar altimeter returns to generate a valley-seeking, low-altitude trajectory between waypoints for display to the pilot. This system has been flight demonstrated to 150 ft above ground level altitude, and is primarily limited by the ability of the pilot to perform obstacle detection and avoidance. In this study, a wide field of view forward sensor has been modeled and incorporated in the guidance system for the purpose of relieving the pilot of the obstacle avoidance duty. The results of a piloted, motion-based simulation of this enhanced low-altitude guidance system is presented. Simulated flights to 50 ft altitude in the presence of obstacles were demonstrated while maintaining situational awareness and close tracking of the guidance trajectory.

  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. A strategy for oxygen conditioning at high altitude: comparison with air conditioning.

    Science.gov (United States)

    West, John B

    2015-09-15

    Large numbers of people live or work at high altitude, and many visit to trek or ski. The inevitable hypoxia impairs physical working capacity, and at higher altitudes there is also cognitive impairment. Twenty years ago oxygen enrichment of room air was introduced to reduce the hypoxia, and this is now used in dormitories, hotels, mines, and telescopes. However, recent advances in technology now allow large amounts of oxygen to be obtained from air or cryogenic oxygen sources. As a result it is now feasible to oxygenate large buildings and even institutions such as hospitals. An analogy can be drawn between air conditioning that has improved the living and working conditions of millions of people who live in hot climates and oxygen conditioning that can do the same at high altitude. Oxygen conditioning is similar to air conditioning except that instead of cooling the air, the oxygen concentration is raised, thus reducing the equivalent altitude. Oxygen conditioning on a large scale could transform living and working conditions at high altitude, where it could be valuable in homes, hospitals, schools, dormitories, company headquarters, banks, and legislative settings.

  19. Using a Convection Model to Predict Altitudes of White Stork Migration Over Central Israel

    Science.gov (United States)

    Shamoun-Baranes, Judy; Liechti, Olivier; Yom-Tov, Yoram; Leshem, Yossi

    Soaring migrants such as storks, pelicans and large birds of prey rely on thermal convection during migration. The convection model ALPTHERM was designed to predict the onset, strength, duration and depth of thermal convection for varying topographies for glider pilots, based on atmospheric conditions at midnight. We tested ALPTHERM predictions as configured for two topographies of central Israel, the Coastal Plains and the Judean and Samarian Mountains in order to predict altitudes of migrating white storks (Ciconia ciconia). Migrating flocks of white storks were tracked with a motorized glider, to measure maximum altitudes of migration during spring 2000. A significant positive correlation was found between the maximum daily altitudes of migration measured and the predicted upper boundary of thermal convection for the Coastal Plains and Samarian Mountains. Thirty-minute predictions for the Coastal Plains and Samarian Mountains correlated positively with measured maximum migration altitudes per thermal. ALPTHERM forecasts can be used to alter flight altitudes in both civil and especially military aviation and reduce the hazard of serious aircraft collisions with soaring migrants.

  20. Development and quality of pineapple guava fruit in two locations with different altitudes in Cundinamarca, Colombia

    Directory of Open Access Journals (Sweden)

    Alfonso Parra-Coronado

    2015-01-01

    Full Text Available Fruit growth is stimulated by different weather conditions. The aim of this study was to determine the influence of weather conditions on the physicochemical properties of pineapple guava fruit growth. Twenty trees were marked in two production areas located at different altitudes (1,800 and 2,580 m.a.s.l., and measurements were performed every 7 days from 99 and 141 days post-anthesis to harvest at altitudes of 1,800 and 2,580 m.a.s.l., respectively. The results indicate that altitude and weather conditions greatly influence the growth and development of pineapple guava fruit, and these effects are primarily manifested in the physical characteristics of the fruit. The weight and size of the fruit at harvest are directly related to the altitude of the production area. The weather condition that has the greatest impact on total titratable acidity at harvest is cumulative radiation during fruit growth; the highest value of total soluble solids at harvest corresponds to the location with the higher altitude, lower rainfall and relative humidity and higher cumulative radiation during the fruit growth period. The hue angle and pulp firmness at harvest are not influenced by the location or weather conditions at any location and do not determine the fruit quality at harvest time.

  1. 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.

  2. Influence of the ionosphere on the altitude of discrete auroral arcs

    Directory of Open Access Journals (Sweden)

    C. S. Deehr

    2005-03-01

    Full Text Available The altitude of the maximum luminosity of single, discrete auroral arcs was measured by photometric triangulation from two stations (College and Fort Yukon, Alaska located 226km apart on nearly the same magnetic meridian. The average height of the evening aurora decreases smoothly with increasing solar depression angle (sda from 160km near 12° sda to 100km after 18° sda. The average height remains constant until around 12° sda in the morning. This diurnal variation is similar to that of the electron density in the F region of the ionosphere. Thus, the behavior is consistent with the concept that the mean auroral electron energy increases as the ionospheric conductivity decreases due to ionospheric recombination in the evening twilight. However, the mean electron energy decreases in magnitude at dawn when the solar ionizing radiation returns and the electron density in the F region increases. The magnetospheric acceleration mechanism associated with discrete auroral arcs thus appears to be inversely proportional to the ionospheric conductivity, because the time variation of the acceleration mechanism coincides with the local F region electron density and not with any obvious magnetospheric process. Previous auroral altitude observations, using similar triangulation methods, showed that the altitude of discrete auroral arcs increases as a function of latitude. When these data are corrected for the twilight effect, the dependence of altitude on latitude disappears. Thus, the average altitude of discrete auroral arcs and, by inference the magnetospheric auroral electron acceleration mechanism, is significantly influenced by the initial ionospheric conductance.

  3. Moderate Altitude Affects High Intensity Running Performance in a Collegiate Women’s Soccer Game

    Directory of Open Access Journals (Sweden)

    Bohner Jonathan D.

    2015-09-01

    Full Text Available The effect of altitude on soccer game activity profiles was retrospectively examined in six NCAA Division I female soccer players. Comparisons were made between two matches played at sea level (SL and one match played at a moderate altitude (1839 m. A 10-Hz global positioning system device was used to measure distance and velocity. The rate of total distance capacity (TDC and high intensity running (HIR as well as percent of time at HIR were evaluated. Significant differences were seen in the distance rate (120.55 ± 8.26 m·min-1 versus 105.77 ± 10.19 m·min-1 and the HIR rate (27.65 ± 9.25 m·min-1 versus 25.07 ± 7.66 m·min-1 between SL and altitude, respectively. The percent of time at HIR was not significantly different (p = 0.064, yet tended to be greater at SL (10.4 ± 3.3% than at altitude (9.1 ± 2.2%. Results indicate that teams residing at SL and competing at a moderate altitude may have a reduced ability in distance covered and a high intensity run rate.

  4. Moderate Altitude Affects High Intensity Running Performance in a Collegiate Women's Soccer Game.

    Science.gov (United States)

    Bohner, Jonathan D; Hoffman, Jay R; McCormack, William P; Scanlon, Tyler C; Townsend, Jeremy R; Stout, Jeffrey R; Fragala, Maren S; Fukuda, David H

    2015-09-29

    The effect of altitude on soccer game activity profiles was retrospectively examined in six NCAA Division I female soccer players. Comparisons were made between two matches played at sea level (SL) and one match played at a moderate altitude (1839 m). A 10-Hz global positioning system device was used to measure distance and velocity. The rate of total distance capacity (TDC) and high intensity running (HIR) as well as percent of time at HIR were evaluated. Significant differences were seen in the distance rate (120.55 ± 8.26 m·min-1 versus 105.77 ± 10.19 m·min-1) and the HIR rate (27.65 ± 9.25 m·min-1 versus 25.07 ± 7.66 m·min-1) between SL and altitude, respectively. The percent of time at HIR was not significantly different (p = 0.064), yet tended to be greater at SL (10.4 ± 3.3%) than at altitude (9.1 ± 2.2%). Results indicate that teams residing at SL and competing at a moderate altitude may have a reduced ability in distance covered and a high intensity run rate. PMID:26557199

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

    Science.gov (United States)

    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.

  6. Optimization with numerical simulations of the conjugate altitudes of deformable mirrors in an MCAO system

    CERN Document Server

    Femenia, B

    2003-01-01

    This article reports on the results of simulations conducted to assess the performance of a modal Multi-Conjugate Adaptive Optics (MCAO) system on a 10m telescope with one Deformable Mirror (DM) conjugated to the telescope pupil and a second DM conjugated at a certain altitude above the pupil. The main goal of these simulations is to study the dependence of MCAO performance upon the altitude of the high-altitude conjugated DM and thereby determine its optimal conjugation. The performance is also studied with respect to the geometry of the Guide Star constellation when using constellations of Natural Guide Stars (NGS), which are rare, or constellations of Laser Guide Stars (LGS) which would allow large sky coverage.

  7. Albuminuria and overall capillary permeability of albumin in acute altitude hypoxia

    DEFF Research Database (Denmark)

    Hansen, J M; Olsen, Niels Vidiendal; Feldt-Rasmussen, B;

    1994-01-01

    The mechanism of proteinuria at high altitude is unclear. Renal function and urinary excretion rate of albumin (Ualb) at rest and during submaximal exercise and transcapillary escape rate of 125I-labeled albumin (TERalb) were investigated in 12 normal volunteers at sea level and after rapid...... groups. Exercise did not reveal any further renal dysfunction. In both groups, high altitude increased TERalb from 4.8 to > 6.7%/h (P function and independent of effects of isradipine on filtration fraction...... and passive ascent to 4,350 m. The calcium antagonist isradipine (5 mg/day; n = 6) or placebo (n = 6) was administered to abolish hypoxia-induced rises in blood pressure. Lithium clearance and urinary excretion of beta 2-microglobulin were used to evaluate renal tubular function. High altitude increased Ualb...

  8. Association between Serum Interleukin-17A Level and High-Altitude Deacclimatization Syndrome.

    Science.gov (United States)

    He, Binfeng; Li, Hongli; Hu, Mingdong; Dong, Weijie; Wei, Zhenghua; Li, Jin; Yao, Wei; Guo, Xiaolan

    2016-01-01

    High-altitude deacclimatization syndrome (HADAS) is emerging as a severe public health issue that threatens the quality of life of individuals who return to lower altitude from high altitude. In this study, we measured serum levels of SOD, MDA, IL-17A, IL-10, TNF-α, and HADAS score in HADAS subjects at baseline and 50th and 100th days and to evaluate the relationship between interleukins, including IL-17A, and HADAS. Our data showed that and the serum IL-17A levels and HADAS score decreased over time in the HADAS group, and serum IL-17A levels were significantly higher in the HADAS group at baseline and 50th day compared with controls (p HADAS subjects compared with controls (p HADAS incidence and severity (p HADAS incidence than serum levels of IL-17A or IL-10 alone. These data suggest that serum levels of IL-17A are a novel predictive index of HADAS.

  9. 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

    . Global cerebral blood flow at rest and during exercise on a bicycle ergometer was measured by the Kety-Schmidt technique. Cerebral metabolic rates of oxygen, glucose, and lactate were calculated by the Fick principle. Cerebral function was assessed by a computer-based measurement of reaction time...... 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......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...

  10. A Robust Photogrammetric Processing Method of Low-Altitude UAV Images

    Directory of Open Access Journals (Sweden)

    Mingyao Ai

    2015-02-01

    Full Text Available Low-altitude Unmanned Aerial Vehicles (UAV images which include distortion, illumination variance, and large rotation angles are facing multiple challenges of image orientation and image processing. In this paper, a robust and convenient photogrammetric approach is proposed for processing low-altitude UAV images, involving a strip management method to automatically build a standardized regional aerial triangle (AT network, a parallel inner orientation algorithm, a ground control points (GCPs predicting method, and an improved Scale Invariant Feature Transform (SIFT method to produce large number of evenly distributed reliable tie points for bundle adjustment (BA. A multi-view matching approach is improved to produce Digital Surface Models (DSM and Digital Orthophoto Maps (DOM for 3D visualization. Experimental results show that the proposed approach is robust and feasible for photogrammetric processing of low-altitude UAV images and 3D visualization of products.

  11. Description and preliminary results of a meteorological network for high altitudes

    Science.gov (United States)

    Duran-Montejano, L.

    2003-04-01

    A high resolution meteorological network has been implemented for monitoring temperature, relative humidity and precipitation at very high altitudes. The system is made up by a specially designed “terrestrial buoy” for high altitudes of very low power requirement and great robustness. The complete system consists of seven of these terrestrial buoys installed in less than 20 Km2 and with more than one measuring point per 150 m of altitude difference. A brief description of the system is presented with some of the preliminary results, including spatial generalization of the point meteorological data to the whole domain of the network using a simple spatial interpolation algorithm and a high resolution terrain digital model in order to be used as inputs for eco-biological models.

  12. Aliskiren Trial in Type 2 Diabetes Using Cardio-Renal Endpoints (ALTITUDE): rationale and study design

    DEFF Research Database (Denmark)

    Parving, Hans-Henrik; Brenner, Barry M; McMurray, John J V;

    2009-01-01

    , resuscitated death, myocardial infarction, stroke, unplanned hospitalization for heart failure, onset of end-stage renal disease or doubling of baseline serum creatinine concentration. Secondary endpoints include a composite CV endpoint and a composite renal endpoint. CONCLUSION: ALTITUDE will determine...... the residual renal and cardiovascular risk still remains high. Aliskiren a novel oral direct renin inhibitor that unlike ACEi and ARBs, lowers plasma renin activity, angiotensin I and angiotensin II levels, may thereby provide greater benefit compared to ACEi or ARB alone. METHODS: The primary objective...... of the ALTITUDE trial is to determine whether aliskiren 300 mg once daily, reduces cardiovascular and renal morbidity and mortality compared with placebo when added to conventional treatment (including ACEi or ARB). ALTITUDE is an international, randomized, double-blind, placebo-controlled, parallel-group study...

  13. Subtle Cognitive Dysfunction in Resolving High Altitude Cerebral Edema Revealed by a Clock Drawing Test.

    Science.gov (United States)

    Quigley, Ian; Zafren, Ken

    2016-06-01

    High altitude cerebral edema (HACE) is a life-threatening condition that can affect people who ascend to altitudes above 2500 m. Altered mental status and the presence of ataxia distinguishes HACE from acute mountain sickness (AMS). We describe a patient with subtle cognitive dysfunction, likely due to HACE that had not fully resolved. When he initially presented, the patient appeared to have normal mental status and was not ataxic. The diagnosis of HACE was missed initially but was made when further history became available. Cognitive dysfunction was then diagnosed based on abnormal performance of a clock drawing test. A formal mental status examination, using a clock drawing test, may be helpful in assessing whether a patient at high altitude with apparently normal mental status and with normal gait has HACE. PMID:26874815

  14. 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...

  15. Image Positioning Accuracy Analysis for the Super Low Altitude Remote Sensing Satellite

    Directory of Open Access Journals (Sweden)

    Ming Xu

    2012-10-01

    Full Text Available Super low altitude remote sensing satellites maintain lower flight altitudes by means of ion propulsion in order to improve image resolution and positioning accuracy. The use of engineering data in design for achieving image positioning accuracy is discussed in this paper based on the principles of the photogrammetry theory. The exact line‐of‐sight rebuilding of each detection element and this direction precisely intersecting with the Earth’s elliptical when the camera on the satellite is imaging are both ensured by the combined design of key parameters. These parameters include: orbit determination accuracy, attitude determination accuracy, camera exposure time, accurately synchronizing the reception of ephemeris with attitude data, geometric calibration and precise orbit verification. Precise simulation calculations show that image positioning accuracy of super low altitude remote sensing satellites is not obviously improved. The attitude determination error of a satellite still restricts its positioning accuracy.

  16. A student designed experiment measuring the speed of sound as a function of altitude

    CERN Document Server

    Santostasi, G; Maharjan, P; McAdon, C; Nguyesn, N T; Poudel, S; Pradhan, S; Roshan, D; Wagle, M

    2008-01-01

    Relatively inexpensive and readily commercially available equipment (such as digital recorders, MP3 portable speakers and tie-pin microphones), allowed a team of students from McNeese State University to measure the speed of sound in the atmosphere as a function of altitude. The experiment was carried as a payload (in the context of a NASA funded student program called La-ACES) on a high altitude balloon that reached a maximum altitude of 101,000 feet. Not withstanding substantial environmental noise, our particular experimental design allowed for the filtering of the signal out of the noise, thus achieving remarkable accuracy and precision. The speed of sound measurement was then used to set limits on the abundances of the main molecular components of the atmosphere (diatomic nitrogen and oxygen). Bayesian analysis was used to set meaningful values on the uncertainty of our limits. It is our experience that students find intutive and appealing this type of probability method.

  17. Modeling of the Stepped Leader Initiation Process in an Altitude Triggered Lightning

    Directory of Open Access Journals (Sweden)

    Bo Zhang

    2016-01-01

    Full Text Available In an altitude triggered lightning, the potential and charge distribution of the triggering wire, a floating conductor, is unknown and changeable during the triggering process, which makes it difficult to simulate an altitude triggered lightning in a numerical work. To solve this problem, a 3D altitude triggered lightning model is developed in this paper, which contains two parts, a Thundercloud Model which is time-dependent and nonhydrostatic and takes 27 kinds of microphysical processes into consideration and a Triggering Model in which a charge conservation equation is introduced to describe the floating conductor and to ensure the overall neutrality of the leader channel. Numerical results of the stepped leader initiation process are given, which are in good agreement with experiment observations.

  18. Velocity gained and altitude lost in recoveries from inclined flight paths

    Science.gov (United States)

    Pearson, H A; Garvin, J B

    1941-01-01

    A series of charts is given showing the variation of the velocity gained and the altitude lost in dive pullouts with the initial indicated air speed and the dive angle. The effects of the maximum load factor, the drag parameter K, the initial altitude, and the type of recovery on the velocity gained and the altitude lost are also considered. The results were obtained from a step-by-step solution of the equations of motion in which mean values of the air density and the airplane drag coefficient were used. The load-factor variation with time is arbitrarily specified in various ways to simulate pull-out procedures, some of which might be encountered in flight.

  19. Carbonic anhydrase activity in the red blood cells of sea level and high altitude natives.

    Science.gov (United States)

    Gamboa, J; Caceda, R; Gamboa, A; Monge-C, C

    2000-01-01

    Red blood cell carbonic anhydrase (CA) activity has not been studied in high altitude natives. Because CA is an intraerythocytic enzyme and high altitude natives are polycythemic, it is important to know if the activity of CA per red cell volume is different from that of their sea level counterparts. Blood was collected from healthy subjects living in Lima (150m) and from twelve subjects from Cerro de Pasco (4330m), and hematocrit and carbonic anhydrase activity were measured. As expected, the high altitude natives had significantly higher hematocrits than the sea level controls (p = 0.0002). No difference in the CA activity per milliliter of red cells was found between the two populations. There was no correlation between the hematocrit and CA activity.

  20. A gloss of Chronic Hypoxia in normal and diseased individuals at high altitude

    Institute of Scientific and Technical Information of China (English)

    Zubieta-Castillo,G.; Zubieta-Calleja,G.R.; Zubieta-Calleja L.

    2004-01-01

    @@ Introduction Millenary populations that live at high altitude in different continents like Asia (1) and South America (8), have endured biological adaptation in very adverse environmental conditions, of which to our understanding, paradoxically, chronic hypoxia is the most tolerable. Patients with pulmonary diseases at high altitude tolerate tissue hypoxia with an arterial tension (PaO2) even as low as 30 mmHg. Current scientific knowledge has made progress in many areas, clarifying many doubts, however due to preconception and lack of broad social studies chronic hypoxia is still not fully understood. Beings that inhabit different areas of the planet earth have lived under a variety of different hostile conditions: intense cold in the polar regions,intense heat in Africa and in the Middle East desserts,great pressure in the depth of the oceans, intense darkness of the caves and naturally the hypoxia of extreme altitudes.

  1. An altitude and distance correction to the source fluence distribution of TGFs

    CERN Document Server

    Nisi, R S; Gjesteland, T; Collier, A B

    2016-01-01

    The source fluence distribution of terrestrial gamma ray flashes (TGFs) has been extensively discussed in recent years, but few have considered how the TGF fluence distribution at the source, as estimated from satellite measurements, depends on the distance from satellite foot point and assumed production altitude. As the absorption of the TGF photons increases significantly with lower source altitude and larger distance between the source and the observing satellite, these might be important factors. We have addressed the issue by using the tropopause pressure distribution as an approximation of the TGF production altitude distribution and World Wide Lightning Location Network spheric measurements to determine the distance. The study is made possible by the increased number of Ramaty High Energy Solar Spectroscopic Imager (RHESSI) TGFs found in the second catalog of the RHESSI data. One find is that the TGF/lightning ratio for the tropics probably has an annual variability due to an annual variability in the...

  2. Variability with altitude of major histocompatibility complex-related microsatellite loci in goats from Southwest China.

    Science.gov (United States)

    E, G X; Huang, Y F; Zhao, Y J; Na, R S

    2015-01-01

    We aimed to use microsatellite BM1258 loci of the major histocompatibility complex (MHC) as an indicator of the influence of genetic diversity of immunity in goats (Dazu Black, Hechuan White, Meigu, and Tibetan goat). In total, 132 animals comprising 50 Dazu Black goats, 24 Hechuan White goats, 34 Meigu goats, and 24 Tibetan goats were examined. Collectively, 18 different alleles and 42 genotypes were found. The overall observed levels of heterozygosity showed large divergence from the expected levels in the four breeds, and an increase in the mean number of alleles of BM1258 accompanied decreasing altitude of the livestock's habitat. Our results indicate that low-altitude regions or plains were more conducive to genetic material exchange and gene flow between different populations. In addition, it seems that the breeds from low-altitude regions were less susceptible to problems introduced by commercial animals. PMID:26600522

  3. Rich diversity and potency of skin antioxidant peptides revealed a novel molecular basis for high-altitude adaptation of amphibians

    OpenAIRE

    Xinwang Yang; Ying Wang; Yue Zhang; Wen-Hui Lee; Yun Zhang

    2016-01-01

    Elucidating the mechanisms of high-altitude adaptation is an important research area in modern biology. To date, however, knowledge has been limited to the genetic mechanisms of adaptation to the lower oxygen and temperature levels prevalent at high altitudes, with adaptation to UV radiation largely neglected. Furthermore, few proteomic or peptidomic analyses of these factors have been performed. In this study, the molecular adaptation of high-altitude Odorrana andersonii and cavernicolous O....

  4. Heart rate variability changes at 2400 m altitude predicts acute mountain sickness on further ascent at 3000-4300 m altitudes

    Directory of Open Access Journals (Sweden)

    Heikki Mikael Karinen

    2012-08-01

    Full Text Available ObjectiveIf the body fails to acclimatize at high altitude, acute mountain sickness (AMS may result. For the early detection of AMS, changes in cardiac autonomic function measured by heart rate variability (HRV may be more sensitive than clinical symptoms alone. The purpose of this study was to ascertain if the changes in HRV during ascent are related to AMS.MethodsWe followed Lake Louise Score (LLS, arterial oxygen saturation at rest (R-SpO2 and exercise (Ex-SpO2 and HRV parameters daily in 36 different healthy climbers ascending from 2400 m to 6300 m altitudes during five different expeditions.ResultsAfter an ascent to 2400 m, standard deviation (RMSSD2 min, high-frequency power (HF2 min of HRV were 17-51 % and Ex-SpO2 was 3% lower in those climbers who suffered from AMS at 3000- 4300 m than in those only developing AMS later (≥ 5000 m or not at all (all p < 0.01. At the altitude of 2400 m RMSSD2 min ≤ 30 ms and Ex-SpO2 ≤ 91% both had 92% sensitivity for AMS if ascent continued without extra acclimatization days.ConclusionsChanges in supine HRV parameters at 2400 m were related to AMS at 3000-4300 m Thus, diverse analyses of HRV could offer potential markers for identifying the climbers at risk for AMS.

  5. Are Himalayan Sherpas better protected against brain damage associated with extreme altitude climbs?

    Science.gov (United States)

    Garrido, E; Segura, R; Capdevila, A; Pujol, J; Javierre, C; Ventura, J L

    1996-01-01

    1. The potential risk of brain damage when low-landers attempt to climb the highest summits is a well-known fact. However, very little is known about what occurs to Himalayan natives, perfectly adapted to high altitude, when performing the same type of activity. 2. Taking into account their long-life climbing experience at extreme altitudes, we examined seven of the most recognized Sherpas with the aim of performing a comprehensive neurological evaluation based on medical history, physical examination and magnetic resonance brain imaging. We compared them with one group of 21 lowland elite climbers who had ascended to altitudes of over 8000 m, and another control group of 21 healthy individuals who had never been exposed to high altitude. 3. While all of the lowland climbers presented psychoneurological symptoms during or after the expeditions, and 13 of them (61%) showed magnetic resonance abnormalities (signs of mild cortical atrophy and/or periventricular high-intensity signal areas in the white matter), only one Sherpa (14%) showed similar changes in the scans, presenting neurological symptoms at extreme altitude. The neurological examination was normal in all three groups, and no neuroimaging abnormalities were detected in the control group. 4. The significant differences, in both clinical and neuroimaging terms, suggest that Sherpa highlanders have better brain protection when exposed to extreme altitude. Although the key to protection against cerebral hypoxia cannot be established, it is possible that an increase in the usually short period of acclimatization could minimize brain damage in those low-landers who attempt the highest summits without supplementary oxygen. PMID:8697710

  6. Vegetation Carbon Storage, Spatial Patterns and Response to Altitude in Lancang River Basin, Southwest China

    Directory of Open Access Journals (Sweden)

    Long Chen

    2016-01-01

    Full Text Available Vegetation plays a very important role of carbon (C sinks in the global C cycle. With its complex terrain and diverse vegetation types, the Lancang River Basin (LRB of southwest China has huge C storage capacity. Therefore, understanding the spatial variations and controlling mechanisms of vegetation C storage is important to understand the regional C cycle. In this study, data from a forest inventory and field plots were used to estimate and map vegetation C storage distribution in the LRB, to qualify the quantitative relationships between vegetation C density and altitude at sublot and township scale, and a linear model or polynomial model was used to identify the relationship between C density and altitude at two spatial scales and two statistical scales. The results showed that a total of 300.32 Tg C was stored in the LRB, an important C sink in China. The majority of C storage was contributed by forests, notably oaks. The vegetation C storage exhibited nonlinear variation with latitudinal gradients. Altitude had tremendous influences on spatial patterns of vegetation C storage of three geomorphological types in the LRB. C storage decreased with increasing altitude at both town and sublot scales in the flat river valley (FRV region and the mid-low mountains gorge (MMG region, and first increased then decreased in the alpine gorge (AG region. This revealed that, in southwest China, altitude changes the latitudinal patterns of vegetation C storage; especially in the AG area, C density in the mid-altitude (3100 m area was higher than that of adjacent areas.

  7. Proton isotropy boundaries as measured on mid- and low-altitude satellites

    Directory of Open Access Journals (Sweden)

    N. Yu. Ganushkina

    2005-07-01

    Full Text Available Polar CAMMICE MICS proton pitch angle distributions with energies of 31-80 keV were analyzed to determine the locations where anisotropic pitch angle distributions (perpendicular flux dominating change to isotropic distributions. We compared the positions of these mid-altitude isotropic distribution boundaries (IDB for different activity conditions with low-altitude isotropic boundaries (IB observed by NOAA 12. Although the obtained statistical properties of IDBs were quite similar to those of IBs, a small difference in latitudes, most pronounced on the nightside and dayside, was found. We selected several events during which simultaneous observations in the same local time sector were available from Polar at mid-altitudes, and NOAA or DMSP at low-altitudes. Magnetic field mapping using the Tsyganenko T01 model with the observed solar wind input parameters showed that the low- and mid-altitude isotropization boundaries were closely located, which leads us to suggest that the Polar IDB and low-altitude IBs are related. Furthermore, we introduced a procedure to control the difference between the observed and model magnetic field to reduce the large scatter in the mapping. We showed that the isotropic distribution boundary (IDB lies in the region where Rc/ρ~6, that is at the boundary of the region where the non-adiabatic pitch angle scattering is strong enough. We therefore conclude that the scattering in the large field line curvature regions in the nightside current sheet is the main mechanism producing isotropization for the main portion of proton population in the tail current sheet. This mechanism controls the observed positions of both IB and IDB boundaries. Thus, this tail region can be probed, in its turn, with observations of these isotropy boundaries.

    Keywords. Magnetospheric physics (Energetic particles, Precipitating; Magnetospheric configuration and dynamics; Magnetotail

  8. Influences of altitude on growth curves in Tibetan chicken and its hybrid

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Tibetan chicken is a precious resource in Qinghai-Tibet Plateau,China.In order to study its growth rhythm and heterosis of its hybrid,three groups comprising Tibetan chicken (T),Dwarf Recessive White (D) and Tibetan×Dwarf Recessive White (TD) were reared under the same management conditions at low and high altitudes.Body weight and shank length were measured,and growth curves were fitted using Richards model.The results showed that the model fitted well with the chickens' growth courses in weight and shank with R2 at more than 0.99.The high-altitude might retard the growth of chickens,with decreases in inflection point values,final values and maximal growth rates,and prolongation of inflection point time.The final weight,inflection point weight,and maximal growth rates of Tibetan chicken were 1008.3 g,477.9 g and 11.69 g respectively at lowaltitude,and 525.3 g,229.5 g,and 5.12 g at high-altitude.This showed a decline of 47.9%,52.0%,and 56.8% at the high-altitude;the degree of influence of altitude was less than that of Dwarf Recessive White.The TD had high heterosis in weight gain,and at high-altitude the heterosis of final weight,inflection point weight,and maximal growth rates were 59.5%,56.8% and 52.3% respectively.Therefore,the Tibetan×Dwarf Recessive White cross was good for improving the Tibetan chicken.

  9. EFFECT OF MODERATE ALTITUDE ON PERIPHERAL MUSCLE OXYGENATION DURING LEG RESISTANCE EXERCISE IN YOUNG MALES

    Directory of Open Access Journals (Sweden)

    Toshio Matsuoka

    2004-09-01

    Full Text Available Training at moderate altitude (~1800m is often used by athletes to stimulate muscle hypoxia. However, limited date is available on peripheral muscle oxidative metabolism at this altitude (1800AL. The purpose of this study was to determine whether acute exposure to 1800AL alters muscle oxygenation in the vastus lateralis muscle during resistance exercise. Twenty young active male subjects (aged 16 - 21 yr performed up to 50 repetitions of the parallel squat at 1800AL and near sea level (SL. They performed the exercise protocol within 3 h after arrival at 1800 AL. During the exercise, the changes in oxygenated hemoglobin (OxyHb in the vastus lateralis muscle, arterial oxygen saturation (SpO2, and heart rate were measured using near infrared continuous wave spectroscopy (NIRcws and pulse oximetry, respectively. Changes in OxyHb were expressed by Deff defined as the relative index of the maximum change ratio (% from the resting level. OxyHb in the vastus lateralis muscle decreased dramatically from the resting level immediately after the start of exercise at both altitudes. The Deff during exercise was significantly (p < 0.001 lower at 1800AL (60.4 ± 6.2 % than at near SL (74.4 ± 7.6 %. SpO2 during exercise was significantly (p < 0.001 lower at 1800AL (92.0 ± 1.7 % than at near SL (96.7 ± 1.2 %. Differences (SL - 1800AL in Deff during exercise correlated fairly strongly with differences in SpO2 during exercise (r = 0.660. These results suggested that acute exposure to moderate altitude caused a more dramatical decrease in peripheral muscle oxygenation during leg resistance exercise. It is salient to note, therefore , that peripheral muscle oxygenation status at moderate altitude could be evaluated using NIRcws and that moderate altitudes might be effectively used to apply hypoxic stress on peripheral muscles.

  10. Identifying positive selection candidate loci for high-altitude adaptation in Andean populations

    Directory of Open Access Journals (Sweden)

    Bigham Abigail W

    2009-12-01

    Full Text Available Abstract High-altitude environments (>2,500 m provide scientists with a natural laboratory to study the physiological and genetic effects of low ambient oxygen tension on human populations. One approach to understanding how life at high altitude has affected human metabolism is to survey genome-wide datasets for signatures of natural selection. In this work, we report on a study to identify selection-nominated candidate genes involved in adaptation to hypoxia in one highland group, Andeans from the South American Altiplano. We analysed dense microarray genotype data using four test statistics that detect departures from neutrality. Using a candidate gene, single nucleotide polymorphism-based approach, we identified genes exhibiting preliminary evidence of recent genetic adaptation in this population. These included genes that are part of the hypoxia-inducible transcription factor (HIF pathway, a biochemical pathway involved in oxygen homeostasis, as well as three other genomic regions previously not known to be associated with high-altitude phenotypes. In addition to identifying selection-nominated candidate genes, we also tested whether the HIF pathway shows evidence of natural selection. Our results indicate that the genes of this biochemical pathway as a group show no evidence of having evolved in response to hypoxia in Andeans. Results from particular HIF-targeted genes, however, suggest that genes in this pathway could play a role in Andean adaptation to high altitude, even if the pathway as a whole does not show higher relative rates of evolution. These data suggest a genetic role in high-altitude adaptation and provide a basis for genotype/phenotype association studies that are necessary to confirm the role of putative natural selection candidate genes and gene regions in adaptation to altitude.

  11. Response to cooling temperature in infants born at an altitude of 4,330 meters.

    Science.gov (United States)

    Frappell, P B; León-Velarde, F; Aguero, L; Mortola, J P

    1998-12-01

    The metabolic response to reduction in ambient temperature was studied in healthy, full-term, 1-d-old infants in Lima (50 m altitude, n = 20) and Cerro de Pasco (4,330 m, barometric pressure approximately 450 mm Hg, n = 20), Peru. Oxygen consumption (V O2) and carbon dioxide production (V CO2) were measured with an open-flow system as each infant rested quietly in a cylindrical humicrib, at wall temperatures of 35 degrees C (warm) and 26 degrees C (cool). The infants were exposed for 20 min to both temperatures, with the higher temperature followed by the lower, and oxygen consumption (V O2) and carbon dioxide production (V CO2) were measured over the last 8 min of each exposure. Average birth weight in Cerro de Pasco (2,933 +/- 77 g [mean +/- SE]) was less than in Lima (3,457 +/- 73 g). In warm conditions, infants born at high altitude had slightly yet significantly lower body and skin temperatures than did those born at low altitude, with similar values of V O2 and heart rate (HR). Neither body nor skin temperature changed in either group during cooling. At low altitude, cooling increased V O2 ( approximately 34%), whereas no significant increase occurred in the high-altitude group. A similar response occurred for HR. Among several possibilities, the most likely interpretation of the results would be that of a decreased thermogenic capacity in the high-altitude infants because of the correspondingly lower oxygen availability during gestation.

  12. Heart rate variability in 1-day-old infants born at 4330 m altitude.

    Science.gov (United States)

    Mortola, J P; León-Velarde, F; Aguero, L; Frappell, P B

    1999-02-01

    In fetuses and newborn infants heart rate variability changes in conditions of acute and chronic hypoxia; we therefore asked whether heart rate variability of infants born at high altitude differed from that of low-altitude infants. Short-term recordings (4-5 min) of inter-beat intervals were obtained in 19 infants in Lima (50 m altitude) and in 15 infants in Cerro de Pasco (4330 m, barometric pressure approximately 450 mmHg, inspired oxygen pressure approximately 94 mmHg) during quiet rest in warm conditions (ambient temperature, Ta, approximately 35 degrees C). In 12 infants from each group recordings were also obtained during cooling (Ta approximately 26 degrees C). Heart rate variability was evaluated from 512 consecutive inter-beat intervals, with analysis based on time-domain and frequency-domain methods. At warm Ta, heart rate variability did not differ between the two groups. During cooling, heart rate increased only in the low-altitude group. As in the warm, during cooling most parameters of heart rate variability did not differ between the two groups. The only exception was the inter-beat interval power of the high-frequency range of the spectrum (0.15-0.4 Hz), which, at least in adults, is believed to be a reflection of vagal activity, and was greater in the high-altitude group. It is concluded that gestation at high altitude, despite its blunting effects on fetal growth, does not have a major impact on heart rate variability of the newborn. Nevertheless, the possibility that differences in response to cooling may reflect some limitation in heart rate control needs to be examined further.

  13. Study on complexity of plant communities at different altitudes on the Northern Slope of Changbai Mountain

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    By the method of gradient pattern analysis, twenty plots were set at altitudes of 700-2600 m with an interval of 100 m on the northern slope of the Changbai Mountain. The dissimilarity of respective sub-plots in the same community was measured and the complexity of plant communities at different altitudes was analyzed. The result from binary data of tree species in canopy tree indicated that the sub-plots in the communities, except subalpine Betula ermanii forest, showed comparatively high dissimilarity in species composition. Especially, the dissimilarity index (0.7) of broadleaved/Korean pine forest at low altitudes was obviously higher than other communities. The differences are not obvious between communities referring to dark coniferous forest. Comparatively, the dissimilarity in sub-plots of the communities at altitude of 1400 m was slightly higher than that of other communities, which reflected the complexity of tree species compositions of transitory-type communities. For subalpine Betula ermanii forest, tree species composition was simple and showed a high similarity between sub-plots. The results derived from binary data of shrub showed that the dissimilarity index of shrub species in broadleaved/Korean pine forest at low altitudes was higher than that in other communities, but the divergence tendency wasn't so obvious as that of arbor species. The dissimilarity derived from binary data of herb and all plant species at different altitudes showed greatly close tendency, and the differences in herb and all plant species between sub-plots were the greatest for the communities of broad-leaved-Korean pine forest and alpine tundra zone.

  14. Assessment of Muscle Contractile Properties at Acute Moderate Altitude Through Tensiomyography.

    Science.gov (United States)

    Morales-Artacho, Antonio J; Padial, Paulino; Rodríguez-Matoso, Dario; Rodríguez-Ruiz, David; García-Ramos, Amador; García-Manso, Juan Manuel; Calderón, Carmen; Feriche, Belén

    2015-12-01

    Under hypoxia, alterations in muscle contractile properties and faster fatigue development have been reported. This study investigated the efficacy of tensiomyography (TMG) in assessing muscle contractile function at acute moderate altitude. Biceps femoris (BF) and vastus lateralis (VL) muscles of 18 athletes (age 20.1 ± 6.1 years; body mass 65.4 ± 13.9 kg; height 174.6 ± 9.5 cm) were assessed at sea level and moderate altitude using electrically evoked contractions on two consecutive days. Maximum radial displacement (Dm), time of contraction (Tc), reaction time (Td), sustained contraction time (Ts), and relaxation time (Tr) were recorded at 40, 60, 80, and 100 mA. At altitude, VL showed lower Dm values at 40 mA (p = 0.008; ES = -0.237). Biceps femoris showed Dm decrements in all electrical stimulations (p  0.61). In VL, Tc was longer at altitude at 40 (p = 0.031, ES = 0.56), and 100 mA (p = 0.03, ES = 0.51). Regarding Td, VL showed significant increases in all electrical intensities under hypoxia (p ≤ 0.03, ES ≥ 0.33). TMG appears effective at detecting slight changes in the muscle contractile properties at moderate altitude. Further research involving TMG along with other muscle function assessment methods is needed to provide additional insight into peripheral neuromuscular alterations at moderate altitude. PMID:26562625

  15. [Effects of Different Altitudes on Soil Microbial PLFA and Enzyme Activity in Two Kinds of Forests].

    Science.gov (United States)

    Zeng, Qing-ping; He, Bing-hui; Mao, Qiao-zhi; Wu, Yao-peng; Huang, Qi; Li, Yuan

    2015-12-01

    The soil microbial community is an important part in soil ecosystem, and it is sensitive to the ecological environment. Phospholipid-derived fatty acids ( PLFA ) analysis was used to examine variations in soil microbial community diversity and its influencing factors. The results showed that: there existed 48 PLFAs that were significant in the soil samples from six altitudes. The PLFAs of six altitudes with the highest contents were i16:0, 10Me17:0, 10Me18:0 TBSA. The citrus forest exhibited richer soil PLFAs distribution both in type and amount than those in masson pine. The microbial activity and functional diversity of masson pine were increased with increasing altitudes, and citrus forest gradually decreased, the PLFA content of different microbial groups in each altitude were significantly different. The richness index, Shannon-Wiener index and Pielou evenness index of masson pine in low elevation were holistically higher than those in high elevation. However, the highest richness index of citrus forest was in low altitude, the highest Shannon-Wiener index and Pielou evenness index were in high altitude. The PLFAs content of different microbial groups were closely correlated to the soil enzyme activities and environmental factors. The PLFAs of bacteria, actinomycetes, G⁻ (Gram- positive), G⁺ (Gram-negative) were positively correlated with Ure(urease) , Ive(invertase) , CAT( catalase activity) and forest type, the PLFAs of fungi was significantly correlated with Ure, Ive, CAT, the PLFAs of bacteria, fungi, actinomycetes, G⁻ , G⁺ were significantly negatively or less correlated with elevation. Ure, Ive, CAT, forest type and elevation are the pivotal factors controlling the soil microbial biomass and activities. PMID:27012007

  16. Sleep quality alterations in healthy workers at high altitude in Yushu area

    Institute of Scientific and Technical Information of China (English)

    Wu Tianyi; Li Wenxiang; Zhang Jianqing; Qi Shengui; Hao Lijuan; Wen Jialin

    2013-01-01

    During the period of reconstruction after Yushu Earthquake,a large number of sea-level or lowland workers ascended there and worked at altitudes between 3750 m and 4878 m which is a hypoxic environment.To investigate the sleep quality at that altitude,we performed two full polysomnographies (PSGs) in 10 volunteers,who were healthy male workers,aged 31±6.6,born and living at sea level,without experience of pre-altitude exposure.The assessment of subjective sleep quality was performed twice in each volunteer.The first investigations were carried out at sea level in Jinan city (pB=760 torr,1 torr=133.322 4 Pa).The second studies were performed at an altitude of 3750 m (pB=416 tonr) in Yushu Jiegu in the same 10 workers after they lived and worked at that altitude for 5 months.At sea level,workers presented a normal sleep structure and a higher oxygenation during sleep.However,as compared to sea-level sleep,at 3750 m,workers had a shorter total sleep time (TST) (p < 0.001),a longer stage 1 non-rapid eye movement (nREM) sleep (p < 0.05) and a shorter 3+4 nREM and rapid eye movement (REM) sleep (p < 0.05) with a severe sleep hypoxemia (p < 0.01).Our data suggested that sea-level workers revealed a disturbed sleep and a bad sleep quality with a significant sleep hypoxemia at altitude of 3750 m.Strengthening the prevention and treatment are thereby sorely necessary.

  17. Discrete Neural Altitude Control for Hypersonic Vehicle Via Flight Path Angle Tracking

    Directory of Open Access Journals (Sweden)

    Shixing Wang

    2012-09-01

    Full Text Available In this study, the altitude control is analyzed for the longitudinal dynamics of a generic Hypersonic Flight Vehicle (HFV. By transforming altitude command into the tracking of flight path angle with fast dynamics, the system design is focusing on the control of the attitude subsystem. The virtual control is designed with nominal feedback and Neural Network (NN approximation via back-stepping. Under the proposed controller, the Semiglobal Uniform Ultimate Boundedness (SGUUB stability is guaranteed. The slow dynamics are transformed into the parameter estimation problem and the update law is designed. The simulation is presented to show the effectiveness of the proposed control approach.

  18. Coherent Doppler Lidar for Measuring Velocity and Altitude of Space and Arial Vehicles

    Science.gov (United States)

    Amzajerdian, Farzin; Pierrottet, Diego; Hines, Glenn D.; Petway, Larry; Barnes, Bruce W.

    2016-01-01

    A coherent Doppler lidar has been developed to support future NASA missions to planetary bodies. The lidar transmits three laser beams and measures line-of-sight range and velocity along each beam using a frequency modulated continuous wave (FMCW) technique. Accurate altitude and velocity vector data, derived from the line-of-sight measurements, enables the landing vehicle to precisely navigate from several kilometers above the ground to the designated location and execute a gentle touchdown. The same lidar sensor can also benefit terrestrial applications that cannot rely on GPS or require surface-relative altitude and velocity data.

  19. The identification of major component of temu kunci (Kaemferia pandurata Roxb. essential oils on different altitude

    Directory of Open Access Journals (Sweden)

    RETNA BANDRIATI ARNIPUTRI

    2007-04-01

    Full Text Available The aims of this study was to know the major component of essential oils of Temu Kunci (Kaemferia pandurata Roxb. on a different altitude. This research was carried out by method of Stahl destilation at BPTO and GCMS Cromatography at FMIPA UGM for both of from Kerjo (350 m asl and Jumapolo (450 m asl. The difference of altitude of temu kunci’s lives on, the same of major component of essential oil but the content among them was different.

  20. An Adaptive Altitude Information Fusion Method for Autonomous Landing Processes of Small Unmanned Aerial Rotorcraft

    Directory of Open Access Journals (Sweden)

    Xusheng Lei

    2012-09-01

    Full Text Available This paper presents an adaptive information fusion method to improve the accuracy and reliability of the altitude measurement information for small unmanned aerial rotorcraft during the landing process. Focusing on the low measurement performance of sensors mounted on small unmanned aerial rotorcraft, a wavelet filter is applied as a pre-filter to attenuate the high frequency noises in the sensor output. Furthermore, to improve altitude information, an adaptive extended Kalman filter based on a maximum a posteriori criterion is proposed to estimate measurement noise covariance matrix in real time. Finally, the effectiveness of the proposed method is proved by static tests, hovering flight and autonomous landing flight tests.

  1. The effects of altitude and harvest time on the feed value of extensive mountain pastures

    DEFF Research Database (Denmark)

    Koukolova, Veronika; Weisbjerg, Martin Riis; Homolka, Petr;

    2009-01-01

    Twenty-four samples of Czech pasture forages were harvested in the region of Sumava National Park and the Protected Landscape Area from three different altitudes (650, 700 and 850 m above sea level). The samples were analysed for chemical composition, in vitro digestibilities and rumen degradabil......Twenty-four samples of Czech pasture forages were harvested in the region of Sumava National Park and the Protected Landscape Area from three different altitudes (650, 700 and 850 m above sea level). The samples were analysed for chemical composition, in vitro digestibilities and rumen...

  2. 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

  3. "Back-of-the-envelope" wind and altitude correction for 100 metre sprint times

    CERN Document Server

    Mureika, J R

    2000-01-01

    A simple algebraic expression is presented to correct men's and women's 100 metre sprint times for ambient wind and altitude effects. The simplified formula is derived from a more complicated equation of motion used to model the athlete's velocity as a function of time (the velocity curve). This method predicts adjustments to 0-wind and 0-altitude equivalents, which are in excellent agreement to other estimates presented in the literature. The expression is easily programmable on any computer, and could conveniently be used by coaches, meet directors, or the media to assess the performance of athletes and the quality of a race immediately following the event.

  4. Ozone Exposure System Designed and Used to High-Altitude Airship Materials

    Science.gov (United States)

    Miller, Sharon K.

    2005-01-01

    High-altitude airships can receive high doses of ozone over short mission durations. For example, in 1 year at an altitude of 70,000 ft, the ozone fluence (number arriving per unit area) can be as high as 1.2 1024 molecules/sq cm. Ozone exposure at these levels can embrittle materials or change the performance of solar cells. It is important to expose components and materials to the expected ozone dosage to determine if the ozone exposure could cause any mission-critical failures.

  5. Gravity waves and high-altitude CO$_2$ ice cloud formation in the Martian atmosphere

    CERN Document Server

    Yiğit, Erdal; Hartogh, Paul

    2015-01-01

    We present the first general circulation model simulations that quantify and reproduce patches of extremely cold air required for CO$_2$ condensation and cloud formation in the Martian mesosphere. They are created by subgrid-scale gravity waves (GWs) accounted for in the model with the interactively implemented spectral parameterization. Distributions of GW-induced temperature fluctuations and occurrences of supersaturation conditions are in a good agreement with observations of high-altitude CO$_2$ ice clouds. Our study confirms the key role of GWs in facilitating CO$_2$ cloud formation, discusses their tidal modulation, and predicts clouds at altitudes higher than have been observed to date.

  6. Plasma density enhancements in the high-altitude polar cap region observed on Akebono

    Science.gov (United States)

    Ichikawa, Yoh-ichi; Abe, Takumi; Yau, Andrew W.

    2002-05-01

    The plasma density in the polar cap ionosphere is generally low (=103 cm-3) above 4000 km altitude, in which the thermal plasma exhibits a distinctively low electron temperature (K) and low parallel ion drift velocity (dusk side. The occurrence of low electron temperature and ion drift velocity appears to suggest the antisunward convection of high-density plasma into the polar cap, and the decrease in electron temperature due to the disruption of field-aligned heat flux in the high-altitude polar cap.

  7. A Minimum Delta V Orbit Maintenance Strategy for Low-Altitude Missions Using Burn Parameter Optimization

    Science.gov (United States)

    Brown, Aaron J.

    2011-01-01

    Orbit maintenance is the series of burns performed during a mission to ensure the orbit satisfies mission constraints. Low-altitude missions often require non-trivial orbit maintenance Delta V due to sizable orbital perturbations and minimum altitude thresholds. A strategy is presented for minimizing this Delta V using impulsive burn parameter optimization. An initial estimate for the burn parameters is generated by considering a feasible solution to the orbit maintenance problem. An low-lunar orbit example demonstrates the Delta V savings from the feasible solution to the optimal solution. The strategy s extensibility to more complex missions is discussed, as well as the limitations of its use.

  8. Altitude training causes haematological fluctuations with relevance for the Athlete Biological Passport

    DEFF Research Database (Denmark)

    Bonne, Thomas Christian; Lundby, Carsten; Lundby, Anne Kristine;

    2015-01-01

    The impact of altitude training on haematological parameters and the Athlete Biological Passport (ABP) was evaluated in international-level elite athletes. One group of swimmers lived high and trained high (LHTH, n = 10) for three to four weeks at 2130 m or higher whereas a control group (n = 10...... the ABPS threshold at day +14. In the control group, no values exceeded the individual ABP reference range. In conclusion, LHTH induces haematological changes in Olympic-level elite athletes which can exceed the individually generated references in the ABP. Training at altitude should be considered...

  9. 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

    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...

  10. EMIC waves observed by the low-altitude satellite DEMETER during the November 2004 magnetic storm

    Science.gov (United States)

    Píša, D.; Parrot, M.; Santolík, O.; Menietti, J. D.

    2015-07-01

    This paper presents an analysis of ULF (0-20 Hz) waves observed by the low-altitude satellite Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions (DEMETER) during the magnetic storm of November 2004. Since these ULF waves are measured by both electric and magnetic antennas, they may be identified as electromagnetic ion cyclotron (EMIC) waves. While EMIC waves have been previously observed in the low-altitude ionosphere, this is the first time that they are observed for such extensive time periods and at such high frequencies. A common feature of these emissions is that their observation region in the low-altitude ionosphere extends continuously from the high-latitude southern trough in one side up to the high-latitude northern trough. The analysis of wave propagation points to the possible source region placed in the inner magnetosphere (L ˜ 2-3). Observed wave frequencies indicate that waves must be generated much farther from the Earth compared to the satellite orbit. Exceptionally high frequencies of about 10 Hz can be explained by the source region placed in the deep inner magnetosphere at L ˜ 2.5. We hypothesize that these waves are generated below the local helium gyrofrequency and propagate over a large range of wave normal angles to reach low altitudes at L ˜ 1.11. In order to investigate this scenario, a future study based on ray tracing simulations will be necessary.

  11. 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. ru...

  12. 14 CFR 91.411 - Altimeter system and altitude reporting equipment tests and inspections.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Altimeter system and altitude reporting equipment tests and inspections. 91.411 Section 91.411 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... RULES Maintenance, Preventive Maintenance, and Alterations § 91.411 Altimeter system and...

  13. 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.

  14. Liver function in rats acclimatized to a simulated altitude of 5500 m.

    Science.gov (United States)

    Ou, Lo Chang; Faulkner, Charles; Tam, Vincent; Leiter, James C

    2013-12-01

    We examined the functional and morphological characteristics of the liver in rats acclimatized to a simulated altitude of 5500 m. We examined the metabolic activity and cytoplasmic distribution of liver mitochondria and the capacity of the liver to regenerate after partial hepatectomy. Mitochondrial respiration, oxidative phosphorylation, the respiratory control ratio (RCR), and the morphological characteristics of mitochondria in liver sections were studied after 3 months acclimatization to high altitude (HA). Partial hepatectomy was performed in a subset of animals after 30 days acclimatization to 5500 m. The rate of hepatic regeneration, induction of ornithine decarboxylase and uridine diphosphate glucuronyltransferase (UGT1a1), and plasma bilirubin were measured 24, 48, 72, and 96 hours after hepatectomy. Acclimatization to 5500 m did not affect the mitochondrial respiratory capacity or oxidative phosphorylation. The RCR decreased and acid phosphatase activity increased, which suggests that there were subtle changes in mitochondrial integrity. In addition, mitochondria were distributed more homogeneously in hepatocytes. Hepatic regeneration, which was associated with 25-fold induction of the ornithine decarboxylase, did not differ between controls and the altitude-exposed animals. Plasma bilirubin levels rose markedly 24 hours after hepatectomy, but returned to control levels 48 hours after the operation in the altitude-exposed animals. Thus, the remarkable functional capacity of the liver was retained at simulated HA. Redistribution of hepatic mitochondria seems to play an important role in maintaining hepatic function despite severe cellular hypoxia.

  15. Altitude acclimatization improves submaximal cognitive performance in mice and involves an imbalance of the cholinergic system.

    Science.gov (United States)

    Guerra-Narbona, R; Delgado-García, J M; López-Ramos, J C

    2013-06-15

    The aim of this work was to reveal a hypothetical improvement of cognitive abilities in animals acclimatized to altitude and performing under ground level conditions, when looking at submaximal performance, once seen that it was not possible when looking at maximal scores. We modified contrasted cognitive tasks (object recognition, operant conditioning, eight-arm radial maze, and classical conditioning of the eyeblink reflex), increasing their complexity in an attempt to find performance differences in acclimatized animals vs. untrained controls. In addition, we studied, through immunohistochemical quantification, the expression of choline acetyltransferase and acetyl cholinesterase, enzymes involved in the synthesis and degradation of acetylcholine, in the septal area, piriform and visual cortexes, and the hippocampal CA1 area of animals submitted to acute hypobaric hypoxia, or acclimatized to this simulated altitude, to find a relationship between the cholinergic system and a cognitive improvement due to altitude acclimatization. Results showed subtle improvements of the cognitive capabilities of acclimatized animals in all of the tasks when performed under ground-level conditions (although not before 24 h), in the three tasks used to test explicit memory (object recognition, operant conditioning in the Skinner box, and eight-arm radial maze) and (from the first conditioning session) in the classical conditioning task used to evaluate implicit memory. An imbalance of choline acetyltransferase/acetyl cholinesterase expression was found in acclimatized animals, mainly 24 h after the acclimatization period. In conclusion, altitude acclimatization improves cognitive capabilities, in a process parallel to an imbalance of the cholinergic system. PMID:23599398

  16. High Altitude Long Endurance (HALE) platforms for tactical wireless communications and sensor use in military operations

    OpenAIRE

    Harbold, Douglas A.

    2001-01-01

    ce-based systems along with their shortfalls, and defines support capabilities from the stratospheric environment. It then provides an in-depth review of emerging high altitude long endurance (HALE) platforms, analyzes HALE platforms survivability, provides a concept of operations (CONOPS) for HALE employment, and performs a HALE platform comparative analysis.

  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. Effets cardiovasculaires d'un bloqueur calcique en hypoxie d'altitude

    DEFF Research Database (Denmark)

    Dugas, L; Dubray, C; Herry, J P;

    1995-01-01

    High altitude pulmonary oedema can be successfully treated and prevented by calcium channel blockers. Moreover, calcium entering in the cells could explain the congestive phenomena of acute mountain sickness (AMS). These findings led us to study the action of a calcium channel blocker, isradipine...

  19. A comparative high-altitude meteorological analysis from three catchments in the Nepalese Himalaya

    NARCIS (Netherlands)

    Shea, J. M.; Wagnon, P.; Immerzeel, W. W.; Biron, R.; Brun, F.; Pellicciotti, F.

    2015-01-01

    Meteorological studies in high-mountain environments form the basis of our understanding of catchment hydrology and glacier accumulation and melt processes, yet high-altitude (>4000 m above sea level, asl) observatories are rare. This research presents meteorological data recorded between December 2

  20. Persistence of chironomids in metal polluted Andean high altitude streams: does melanin play a role?

    NARCIS (Netherlands)

    R.A. Loayza Muro; J.K. Marticorena-Ruíz; E.J. Palomino; C. Merritt; M.L. de Baat; M. van Gemert; R.A. Verweij; M.H.S. Kraak; W. Admiraal

    2013-01-01

    In high altitude Andean streams an intense solar radiation and coinciding metal pollution allow the persistence of only a few specialized taxa, including chironomids. The aim of the present study was therefore to determine the mechanisms underlying the persistence of chironomids under these multiple

  1. Physical activity at altitude: challenges for people with diabetes: a review

    NARCIS (Netherlands)

    Mol, P. de; Vries, S.T. de; Koning, E.J. de; Gans, R.O.; Bilo, H.J.; Tack, C.J.

    2014-01-01

    BACKGROUND: A growing number of subjects with diabetes take part in physical activities at altitude such as skiing, climbing, and trekking. Exercise under conditions of hypobaric hypoxia poses some unique challenges on subjects with diabetes, and the presence of diabetes can complicate safe and succ

  2. 40 CFR Appendix III to Part 1068 - High-Altitude Counties

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false High-Altitude Counties III Appendix III to Part 1068 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS GENERAL COMPLIANCE PROVISIONS FOR ENGINE PROGRAMS Pt. 1068, App. III Appendix III to Part...

  3. High altitude radiation exposure in the SR-71: a preliminary report. Professional study

    Energy Technology Data Exchange (ETDEWEB)

    DeHart, R.M.

    1974-04-01

    A study to measure radiation received by SR-71 crews at high altitudes began at Beale AFB, California in 1971. Data gathered during the first eighteen months are presented. Radiation was measured by a thermoluminescent dosimeter provided by the USAF Radiological Health Laboratory (AFLC).

  4. Altitude survey of the galactic cosmic ray flux with a Mini Neutron Monitor

    Science.gov (United States)

    Lara, A.; Borgazzi, A.; Caballero-Lopez, R.

    2016-10-01

    We present the results of a survey of the galactic cosmic ray (GCR) flux measured at different altitudes, from the sea level, up to ∼4600 m a.s.l. This altitude survey was carried out with a "Mini" Neutron Monitor (MNM), and performed inside a small area of the central part of Mexico (centered around the 19° N and 97° W position) where the geomagnetic cutoff rigidity is ∼7.8 GV. In particular, the latitudinal variation of the survey was less than 1°. making negligible the associated changes in the geomagnetic cutoff rigidity (∼0.4 GV). This is the first time that an altitude survey has been performed using a MNM. This survey allowed us to compute the barometric coefficient β = 0.00732 ± 0.00054mbar-1 and β = 0.00729 ± 0.00055mbar-1 when we correct our data by the differences in the cutoff rigidity. This coefficient may be used to calibrate and correct the data of other cosmic ray detectors. We show that from the sea level up to ∼4600 m the barometric coefficient is constant and does not depend on the altitude as found in previous surveys. For comparison, we also present the counting rates measured by the NM64 located at Mexico City, as well as other observations carried out to determine the stability of the MNM.

  5. Effect of high altitude on sensitivity to the taste of phenylthiocarbamide

    Science.gov (United States)

    Singh, S. B.; Chatterjee, A.; Panjwani, U.; Yadav, D. K.; Selvamurthy, W.; Sharma, K. N.

    Sensitivity to the taste of phenylthiocarbamide (PTC) was studied using the Harris-Kalmus method in healthy human volunteers at sea level and then subsequently at an altitude of 3500 m over a period of 3 weeks, after which they were brought back to sea level. Blood sugar, insulin and blood cortisol levels were estimated weekly. The results indicated that, out of 51 subjects studied, 26 (55%) were PTC tasters at sea level. Eight of those unable to taste PTC at sea level tested as tasters at high altitude, and 2 of them reverted to being non-tasters on return to sea level. In the blood, an increase in cortisol and blood insulin levels was seen without any significant change in sugar levels. All the changes recorded at high altitude tended to return to basal values after re-induction to sea level. The study suggests that high-altitude hypoxia in some way, possibly involving changes in hormonal profile among other factors, causes an alteration in sensitivity to the taste of PTC, resulting in some of the individuals shifting to lower PTC sensitivity.

  6. Threshold altitude for bubble decay and stabilization in rat adipose tissue at hypobaric exposures

    DEFF Research Database (Denmark)

    Randsoe, Thomas; Larsen, Ole Hyldegaard

    2013-01-01

    Bubble formation during altitude exposures, causing altitude decompression sickness (aDCS), has been referred to in theoretical models as venous gas embolisms (VGE). This has also been demonstrated by intravascular gas formation. Previous reports indicate that the formation of VGE and aDCS incide......Bubble formation during altitude exposures, causing altitude decompression sickness (aDCS), has been referred to in theoretical models as venous gas embolisms (VGE). This has also been demonstrated by intravascular gas formation. Previous reports indicate that the formation of VGE and a......DCS incidence increase abruptly for exposures exceeding 40-44 kPa ambient pressures. Further, extravascular micro air bubbles injected into adipose tissue grow transiently, then shrink and disappear while breathing oxygen (F1O2 = 1.0) at 71 kPa. At 25 kPa similar air bubbles will grow and stabilize during...... oxygen breathing without disappearing. We hypothesize that an ambient pressure threshold for either extravascular bubble stabilization or disappearance may be identified between 71 and 25 kPa. Whether extravascular bubbles will stabilize above a certain threshold has not been demonstrated before....

  7. 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.; Takekawam, J.Y.; Natsagdorj, T.; Wikelski, M.; Witt, M.J.; Yan, B.; Bishop, C.M.

    2012-01-01

    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.

  8. Ground-high altitude joint detection of ozone and nitrogen oxides in urban areas of Beijing

    Institute of Scientific and Technical Information of China (English)

    Pengfei Chen; Qiang Zhang; Jiannong Quan; Yang Gao; Delong Zhao; Junwang Meng

    2013-01-01

    Based on observational data of ozone (O3) and nitrogen oxide (NOx) mixing ratios on the ground and at high altitude in urban areas of Beijing during a period of six days in November 2011,the temporal and spatial characteristics of mixing ratios were analyzed.The major findings include:urban O3 mixing ratios are low and NOx mixing ratios are always high near the road in November.Vertical variations of the gases are significantly different in and above the planetary boundary layer.The mixing ratio of O3 is negatively correlated with that of NOx and they are positively correlated with air temperature,which is the main factor directly causing vertical variation of O3 and NOx mixing ratios at 600-2100 m altitude.The NOx mixing ratios elevated during the heating period,while the O3 mixing ratios decreased:these phenomena are more significant at high altitudes compared to lower altitudes.During November,air masses in the urban areas of Beijing are brought bynorthwesterly winds,which transport O3 and NOx at low mixing ratios.Due to Beijing's natural geographical location,northwest air currents are beneficial to the dilution and dispersion of pollutants,which can result in lower O3 and NOx background values in the Beijing urban area.

  9. Ground-high altitude joint detection of ozone and nitrogen oxides in urban areas of Beijing.

    Science.gov (United States)

    Chen, Pengfei; Zhang, Qiang; Quan, Jiannong; Gao, Yang; Zhao, Delong; Meng, Junwang

    2013-04-01

    Based on observational data of ozone (O3) and nitrogen oxide (NO(x)) mixing ratios on the ground and at high altitude in urban areas of Beijing during a period of six days in November 2011, the temporal and spatial characteristics of mixing ratios were analyzed. The major findings include: urban O3 mixing ratios are low and NO(x) mixing ratios are always high near the road in November. Vertical variations of the gases are significantly different in and above the planetary boundary layer. The mixing ratio of O3 is negatively correlated with that of NO(x) and they are positively correlated with air temperature, which is the main factor directly causing vertical variation of O3 and NO(x) mixing ratios at 600-2100 m altitude. The NO(x) mixing ratios elevated during the heating period, while the O3 mixing ratios decreased: these phenomena are more significant at high altitudes compared to lower altitudes. During November, air masses in the urban areas of Beijing are brought by northwesterly winds, which transport O3 and NO(x) at low mixing ratios. Due to Beijing's natural geographical location, northwest air currents are beneficial to the dilution and dispersion of pollutants, which can result in lower O3 and NO(x) background values in the Beijing urban area.

  10. Influence of altitude on the height of blue cone in a premixed flame

    Energy Technology Data Exchange (ETDEWEB)

    Amell, Andres A. [Gas Science and Technology Group, Engineering Faculty, University of Antioquia, Calle 67 No. 53-108 Bloque 20-435, Medellin (Colombia)

    2007-02-15

    For economic and environmental reasons natural gas begins to take an important participation as an energy source in the residential sector of Latin American cities placed at high altitudes: La Paz (3719m), Santa Fe de Bogota (2600m), Mexico City (2240m), Manizales (2150m), Medellin (1550m), Cali (1000m) and others. One of the most widely used natural gas systems in the residential sector is the partially aerated burner. The height of the blue cone in a premixed flame increases as the altitude above sea level becomes greater. In this work this behavior is determined experimentally, for this purpose tests were carried out in colombian location placed at 40, 550, 1220, 2040 and 2550m above sea level. In every place of tests three replicas were performed, keeping constant the following variables: chemical composition of natural gas, with a methane content of 98%, gas pressure discharge at the injector at 20mbar, injector diameter in 1.35mm, mixer geometry and port diameter in 17mm. The images of the blue cone were captured with a Pixera digital camera for images registration. Images were stored to determine later, through the software Matrox Inspector for images analysis, the height of the blue cone in each experiment for the different altitudes. It was found that the height of the blue cone is increased in 1.49+/-0.12mm by each 304m (1000feet) rise in altitude. (author)

  11. Reversibility of electrophysiological changes induced by chronic high-altitude hypoxia in adult rat heart.

    Science.gov (United States)

    Chouabe, C; Amsellem, J; Espinosa, L; Ribaux, P; Blaineau, S; Mégas, P; Bonvallet, R

    2002-04-01

    Recent studies indicate that regression of left ventricular hypertrophy normalizes membrane ionic current abnormalities. This work was designed to determine whether regression of right ventricular hypertrophy induced by permanent high-altitude exposure (4,500 m, 20 days) in adult rats also normalizes changes of ventricular myocyte electrophysiology. According to the current data, prolonged action potential, decreased transient outward current density, and increased inward sodium/calcium exchange current density normalized 20 days after the end of altitude exposure, whereas right ventricular hypertrophy evidenced by both the right ventricular weight-to-heart weight ratio and the right ventricular free wall thickness measurement normalized 40 days after the end of altitude exposure. This morphological normalization occurred at both the level of muscular tissue, as shown by the decrease toward control values of some myocyte parameters (perimeter, capacitance, and width), and the level of the interstitial collagenous connective tissue. In the chronic high-altitude hypoxia model, the regression of right ventricular hypertrophy would not be a prerequisite for normalization of ventricular electrophysiological abnormalities. PMID:11893582

  12. Deriving historical equilibrium-line altitudes from a glacier length record by linear inverse modelling

    NARCIS (Netherlands)

    Klok, E.J.; Oerlemans, J.

    2003-01-01

    Glaciers have fluctuated in historic times and the length fluctuations of many glaciers are known. From these glacier length records, a climate reconstruction described in terms of a reconstruction of the equilibrium-line altitude (ELA) or the mass-balance can be extracted. In order to derive a clim

  13. Design considerations for combined cooling, heating, and power systems at altitude

    Energy Technology Data Exchange (ETDEWEB)

    Fumo, Nelson; Mago, Pedro J.; Jacobs, Kenneth [Mechanical Engineering Department, Mississippi State University, Mississippi State, MS 39762 (United States)

    2011-02-15

    Combined cooling, heating, and power (CCHP) is a technology that makes better use of fuels as consequence of its high overall efficiency, which can be as high as 80%. CCHP systems aid in the reduction of energy consumption by recovering otherwise wasted heat and using it to provide heating and cooling. As a result, they also have the potential to reduce carbon and other pollutant emissions. Generally, for CCHP systems' components, manufacturers include specifications on the performance of the equipment. However, these specifications are normally given for sea level operation. Changes in altitude affect the performance of any of the CCHP systems' components that are open to the atmosphere due to changes in the properties of the air, such as atmospheric pressure and humidity. This study focuses on considerations for CCHP systems design at altitude. The analysis covers the processes affected by altitude and their specific application on how to assess the performance of the individual components of CCHP systems when operating at altitude. This paper also summarizes the analysis by presenting equations that can be used in the design stage of CCHP systems in order to account for equipment capacity variation, or in simplified simulations such as those for screening tools, without having a detailed simulation that some times are not cost-effective due to the time and human effort to accomplish it. (author)

  14. Ecological implication of variation in the secondary metabolites in Parmelioid lichens with respect to altitude.

    Science.gov (United States)

    Shukla, Vertika; Patel, D K; Bajpai, Rajesh; Semwal, Manoj; Upreti, D K

    2016-01-01

    Lichens are known to synthesize a variety of secondary metabolites having multifunctional activity in response to external environmental condition. Two common lichen extrolites, atranorin and salazinic acid, are known to afford antioxidant as well as photoprotectant nature depending on the abiotic/biotic stress. The present investigation aims to study the influence of altitudinal gradient on the quantitative profile of atranorin and salazinic acid in three lichen species, Bulbothrix setschwanensis (Zahlbr.) Hale, Everniastrum cirrhatum (Fr.) Hale and Parmotrema reticulatum (Taylor) Choisy, Parmeliaceae using liquid chromatography-mass spectrometry (LC-MS/MS) technique. Samples were collected from high-altitude area, usually considered as non-polluted sites of Garhwal Himalaya. Characterization and quantification of the lichen substances in samples were carried out comparing with the standards of atranorin and salazinic acid. Results indicated significant variation in the chemical content with the rising altitude. All the three lichen species showed higher quantities of chemical substances with the altitudinal rise, while among the three lichen species, E. cirrhatum showed the highest quantity of total lichen compounds. The higher abundance and frequency of E. cirrhatum with increasing altitude as compared to B. setschwanensis and P. reticulatum may be attributed due to the presence of higher quantity of photoprotecting/antioxidant chemicals especially salazinic acid. Thus, the present study shows the prominent role of secondary metabolite in wider ecological distribution of Parmelioid lichens at higher altitudes. PMID:26370809

  15. A comparative analysis of the influence of weather on the flight altitudes of birds

    NARCIS (Netherlands)

    J. Shamoun-Baranes; E. van Loon; H. van Gasteren; J. van Belle; W. Bouten; L. Buurma

    2006-01-01

    Birds pose a serious risk to flight safety worldwide. A Bird Avoidance Model (BAM) is being developed in the Netherlands to reduce the risk of bird-aircraft collisions. In order to develop a temporally and spatially dynamic model of bird densities, data are needed on the flight-altitude distribution

  16. Design of a 100 MW laddermill for wind energy generation from 5 km altitude

    NARCIS (Netherlands)

    Lansdorp, B.; Ockels, W.

    2005-01-01

    This paper presents the design of a 100 MW Laddermill. The Laddermill is a novel concept to generate electricity from high altitude winds. The concept allows very large single unit powers. It generates electricity by pulling a rope from a generator, with lift generated by kites. For a 100 MW Ladderm

  17. Bird migration flight altitudes studied by a network of operational weather radars.

    Science.gov (United States)

    Dokter, Adriaan M; Liechti, Felix; Stark, Herbert; Delobbe, Laurent; Tabary, Pierre; Holleman, Iwan

    2011-01-01

    A fully automated method for the detection and quantification of bird migration was developed for operational C-band weather radar, measuring bird density, speed and direction as a function of altitude. These weather radar bird observations have been validated with data from a high-accuracy dedicated bird radar, which was stationed in the measurement volume of weather radar sites in The Netherlands, Belgium and France for a full migration season during autumn 2007 and spring 2008. We show that weather radar can extract near real-time bird density altitude profiles that closely correspond to the density profiles measured by dedicated bird radar. Doppler weather radar can thus be used as a reliable sensor for quantifying bird densities aloft in an operational setting, which--when extended to multiple radars--enables the mapping and continuous monitoring of bird migration flyways. By applying the automated method to a network of weather radars, we observed how mesoscale variability in weather conditions structured the timing and altitude profile of bird migration within single nights. Bird density altitude profiles were observed that consisted of multiple layers, which could be explained from the distinct wind conditions at different take-off sites. Consistently lower bird densities are recorded in The Netherlands compared with sites in France and eastern Belgium, which reveals some of the spatial extent of the dominant Scandinavian flyway over continental Europe. PMID:20519212

  18. Seasonal variation of Titan's haze at low and high altitudes from HST-STIS spectroscopy

    Science.gov (United States)

    Karkoschka, Erich

    2016-05-01

    The Space Telescope Imaging Spectrograph accumulated image cubes of Titan in five years between 1997 and 2004 that we calibrated and analyzed. The observations probe Titan's early northern fall to early winter. Methane bands between 543 and 990 nm wavelength are well resolved spectrally, and Titan's latitudinal and center-to-limb reflectivity variations are resolved spatially. A principal component analysis revealed two large components and two small components of less significance. The first principal component describes a variation of Titan's haze below 80 ± 20 km altitude. Haze particles change their size, opacity, and/or shape of the single scattering phase function. The largest and smallest opacities occurred both in 1997 at high southern latitudes and northern latitudes, respectively. The hemispherical asymmetry switched sign in 2002 at low latitudes, in 2003 at mid latitudes, and in early 2004 at high latitudes. The seasonal amplitude increased almost linearly with distance from the Equator. Tropical latitudes had slightly lower opacities than the annual and global average if the observed variation is seasonally symmetric and shaped like a sine curve. The cause for the variation may be condensation of gases onto aerosols seasonally driven by atmospheric dynamics. The second principal component describes a variation of haze opacity at altitudes above 150 ± 50 km. Largest and smallest opacities both occurred in 2004 at northern and high southern latitudes, respectively. The asymmetry switched in late 2001. Tropical latitudes had significantly higher haze opacity than the annual and global average, opposite to the case at low altitudes. The cause for the high-altitude variation may be aerosols transported at varying speeds driven by atmospheric dynamics. We present a seasonal model that completely describes the haze parameters at each altitude, latitude, and time. It compares fairly well with Cassini results obtained since 2004. The north-south asymmetry may

  19. Prevalence of Chronic Mountain Sickness in high altitude districts of Himachal Pradesh

    Directory of Open Access Journals (Sweden)

    Inderjeet Singh Sahota

    2013-01-01

    Full Text Available Introduction: Chronic Mountain Sickness (CMS is a maladaptation condition that can affect people who reside permanently at high altitude (HA. It is characterized by polycythemia, hypoxemia and dyspnea and can be fatal. Over 140 million people live permanently at HA around the world. Unfortunately, research into CMS is lacking and accurate data on the prevalence of this condition do not exist for many regions around the world. In this study, we sought to examine prevalence rates of CMS in the Indian Himalayas, focusing on the Northern State of Himachal Pradesh. Materials and Methods: We surveyed 83 individuals (69 males in eight towns across the HA districts of Sirmaur, Kinnaur and Lahaul and Spiti in Himachal Pradesh, India. Altitudes ranged from 2350 to 4150 m. We used an adapted Qinghai CMS scoring system to diagnose CMS. Information related to subject demographics, medical history, socioeconomic status, and geography were collected to identify risk factors for CMS. Physiologic recordings of oxygen saturation (SpO 2 and pulse rate were made through pulse oximetry. Results: Overall CMS prevalence was 6.17% and mean altitude was 3281 m. At altitudes above 3000 m CMS prevalence rose to 13.73%. All cases of CMS were mild and there was a significant positive correlation between CMS scores and altitude (R = 0.784, P = 0.0213. Mean SpO 2 was 90.7 ± 0.4% and mean pulse rate was 80.3 ± 1.3 bpm. SpO 2 significantly correlated with altitude (R = −0.929, P < 0.001. In our study, age, gender, and tobacco use were not independent risk factors for CMS. Individuals with CMS lived at higher altitudes than their non-CMS counterparts (3736.00 ± 113.30 m vs. 3279.80 ± 69.50 m, respectively; P = 0.017. Conclusion: CMS prevalence in HA towns of the Indian Himalayas of Himachal Pradesh is 6.17% and 13.73% for towns above 3000 m. Further research is required to determine the prevalence of CMS in other regions of the world and to determine risk factors

  20. Rhizosphere effect on phosphorus availability in forest soils at different altitudes.

    Science.gov (United States)

    De Feudis, Mauro; Cardelli, Valeria; Massaccesi, Luisa; Bol, Roland; Willbold, Sabine; Cocco, Stefania; Corti, Giuseppe; Agnelli, Alberto

    2016-04-01

    Phosphorus (P) is an essential nutrient for plants but it is one of the least available mineral nutrients, and can substantially limit plant growth. Although plants are able to respond to the P shortage, the global warming might modify the soil-plant-microorganisms system and reduce P availability. We evaluated the rhizosphere effect of beech (Fagus sylvatica L.) in forest soils of the Apennines mountains (central Italy) at two altitudes (800 and 1000 m) and along 1° of latitudinal gradient, using latitude and altitude as proxies for temperature change. Specifically, we tested if 1) soil organic C, total N, and organic and available P decrease with increasing latitude and altitude, and 2) the rhizosphere effect on P availability becomes more pronounced when potential nutrient limitations are more severe, as it happens with increasing latitude and altitude. The results suggested that the small latitudinal gradient has no effect on soil properties. Conversely, significant changes occurred between 800 and 1000 m a.s.l., as the soils at higher altitude showed greater TOC, organic and available P contents, and alkaline mono-phosphatases activity than the soils at 800 m a.s.l. Compared to the soils at lower altitude, a marked rhizosphere effect was found at 1000 m a.s.l., and it was mainly attributed to the release of labile organics through rhizodeposition processes. These labile organic compounds were considered able to induce a "priming effect" that fostered the mineralization of the soil organic matter. The enhanced organic carbon cycling, in turn, likely promoted the mineralization of the organic P forms. This was supported by the smaller proportion of orthophosphate monoesters found in the P pool of the rhizosphere than in that of the soil far from the roots, with a consequent increase of the amount of available P. Hence, we speculate that at high altitude the energy supplied by the plants through rhizodeposition to the rhizosphere heterotrophic microbial

  1. Ultraviolet-B-driven pigmentation and genetic diversity of benthic macroinvertebrates from high-altitude Andean streams

    NARCIS (Netherlands)

    R.A. Loayza Muro; J.K. Marticorena-Ruíz; E.J. Palomino; C Merrit; J.A.J. Breeuwer; P. Kuperus; M.H.S. Kraak; W. Admiraal

    2013-01-01

    Photoprotective pigments in benthic macroinvertebrates may reduce the damage caused by the blistering UV-B radiation in Andean high-altitude streams above 3500 m. The aim of this study was therefore to determine whether melanisation in macroinvertebrates inhabiting high-altitude Andean streams is an

  2. Deep Vein Thrombosis and Pulmonary Embolism in a Mountain Guide: Awareness, Diagnostic Challenges, and Management Considerations at Altitude.

    Science.gov (United States)

    Hull, Claire M; Rajendran, Dévan; Fernandez Barnes, Arturo

    2016-03-01

    High intensity exercise is associated with several potentially thrombogenic risk factors, including dehydration and hemoconcentration, vascular trauma, musculoskeletal injuries, inflammation, long-distance travel, and contraceptive usage. These are well documented in case reports of venous thrombosis in track and field athletes. For mountaineers and those working at high altitude, additional risks exist. However, despite there being a high degree of vigilance for "classic" conditions encountered at altitude (eg, acute mountain sickness, high altitude pulmonary edema, and high altitude cerebral edema), mainstream awareness regarding thrombotic conditions and their complications in mountain athletes is relatively low. This is significant because thromboembolic events (including deep vein thrombosis, pulmonary embolism, and cerebral vascular thrombosis) are not uncommon at altitude. We describe a case of deep vein thrombosis and pulmonary embolism in a male mountain guide and discuss the diagnostic issues encountered by his medical practitioners. Potential risk factors affecting blood circulation (eg, seated car travel and compression of popliteal vein) and blood hypercoagulability (eg, hypoxia, environmental and psychological stressors [avalanche risk, extreme cold]) relevant to the subject of this report and mountain athletes in general are identified. Considerations for mitigating and managing thrombosis in addition to personalized care planning at altitude are discussed. The prevalence of thrombosis in mountain athletes is uncharted, but lowlanders increasingly go to high altitude to trek, ski, or climb. Blood clots can and do occur in physically active people, and thrombosis prevention and recognition will demand heightened awareness among participants, healthcare practitioners, and the altitude sport/leisure industry at large. PMID:26723546

  3. Vertical mixing of commercial aviation emissions from cruise altitude to the surface

    Science.gov (United States)

    Whitt, D. B.; Jacobson, M. Z.; Wilkerson, J. T.; Naiman, A. D.; Lele, S. K.

    2011-07-01

    Data analysis and numerical simulations were used to examine vertical transport of cruise-altitude commercial aircraft emissions to the surface. First, aircraft emission data were compared with static stability and potential temperature data from satellites. Second, we ran global 3-D simulations of a passive tracer released uniformly at 11 km (cruise altitude). We present global, regional, and seasonal results of the data comparisons as well as approximate time scales of vertical mixing derived from the simulations. Using the year 2006 as a case study, we found that 24% of all global commercial aviation emissions occurred in the stratosphere, 17% occurred both north of 40° N and above the 330 K isentrope, and 54% occurred in regions of at least moderate static stability (N2 > 10-4 s-2). In addition, 74% of emissions in the Arctic Circle were in the stratosphere. In the 3-D simulations, the globally averaged tracer-plume e-folding lifetime against vertical transport to any other altitude was 16 days during January and 14 days during July. Furthermore, the passive tracer took 15 days longer in January (77 days) compared with July (62 days) to achieve a surface-to-cruise mixing ratio fraction greater than 0.5 at all latitudes. The dynamical mixing time scales of extratropical cruise-altitude emissions were significantly longer than the globally averaged wet removal time of 4-5 days for aerosol particles emitted in the lower troposphere. Thus, it is unlikely that cruise-altitude emissions affect surface air quality via transport alone outside the tropics.

  4. Self-Constrained Euler Deconvolution Using Potential Field Data of Different Altitudes

    Science.gov (United States)

    Zhou, Wenna; Nan, Zeyu; Li, Jiyan

    2016-06-01

    Euler deconvolution has been developed as almost the most common tool in potential field data semi-automatic interpretation. The structural index (SI) is a main determining factor of the quality of depth estimation. In this paper, we first present an improved Euler deconvolution method to eliminate the influence of SI using potential field data of different altitudes. The different altitudes data can be obtained by the upward continuation or can be directly obtained by the airborne measurement realization. Euler deconvolution at different altitudes of a certain range has very similar calculation equation. Therefore, the ratio of Euler equations of two different altitudes can be calculated to discard the SI. Thus, the depth and location of geologic source can be directly calculated using the improved Euler deconvolution without any prior information. Particularly, the noise influence can be decreased using the upward continuation of different altitudes. The new method is called self-constrained Euler deconvolution (SED). Subsequently, based on the SED algorithm, we deduce the full tensor gradient (FTG) calculation form of the new improved method. As we all know, using multi-components data of FTG have added advantages in data interpretation. The FTG form is composed by x-, y- and z-directional components. Due to the using more components, the FTG form can get more accurate results and more information in detail. The proposed modification method is tested using different synthetic models, and the satisfactory results are obtained. Finally, we applied the new approach to Bishop model magnetic data and real gravity data. All the results demonstrate that the new approach is utility tool to interpret the potential field and full tensor gradient data.

  5. Characteristics and drivers of high-altitude ladybird flight: insights from vertical-looking entomological radar.

    Directory of Open Access Journals (Sweden)

    Daniel L Jeffries

    Full Text Available Understanding the characteristics and drivers of dispersal is crucial for predicting population dynamics, particularly in range-shifting species. Studying long-distance dispersal in insects is challenging, but recent advances in entomological radar offer unique insights. We analysed 10 years of radar data collected at Rothamsted Research, U.K., to investigate characteristics (altitude, speed, seasonal and annual trends and drivers (aphid abundance, air temperature, wind speed and rainfall of high-altitude flight of the two most abundant U.K. ladybird species (native Coccinella septempunctata and invasive Harmonia axyridis. These species cannot be distinguished in the radar data since their reflectivity signals overlap, and they were therefore analysed together. However, their signals do not overlap with other, abundant insects so we are confident they constitute the overwhelming majority of the analysed data. The target species were detected up to ∼1100 m above ground level, where displacement speeds of up to ∼60 km/h were recorded, however most ladybirds were found between ∼150 and 500 m, and had a mean displacement of 30 km/h. Average flight time was estimated, using tethered flight experiments, to be 36.5 minutes, but flights of up to two hours were observed. Ladybirds are therefore potentially able to travel 18 km in a "typical" high-altitude flight, but up to 120 km if flying at higher altitudes, indicating a high capacity for long-distance dispersal. There were strong seasonal trends in ladybird abundance, with peaks corresponding to the highest temperatures of mid-summer, and warm air temperature was the key driver of ladybird flight. Climatic warming may therefore increase the potential for long-distance dispersal in these species. Low aphid abundance was a second significant factor, highlighting the important role of aphid population dynamics in ladybird dispersal. This research illustrates the utility of radar for studying high-altitude

  6. 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.

  7. Relationship Between Vertical Jump Height and Swimming Start Performance Before and After an Altitude Training Camp.

    Science.gov (United States)

    García-Ramos, Amador; Padial, Paulino; de la Fuente, Blanca; Argüelles-Cienfuegos, Javier; Bonitch-Góngora, Juan; Feriche, Belén

    2016-06-01

    García-Ramos, A, Padial, P, de la Fuente, B, Argüelles-Cienfuegos, J, Bonitch-Góngora, J, and Feriche, B. Relationship between vertical jump height and swimming start performance before and after an altitude training camp. J Strength Cond Res 30(6): 1638-1645, 2016-This study aimed (a) to analyze the development in the squat jump height and swimming start performance after an altitude training camp, (b) to correlate the jump height and swimming start performance before and after the altitude training period, and (c) to correlate the percent change in the squat jump height with the percent change in swimming start performance. Fifteen elite male swimmers from the Spanish Junior National Team (17.1 ± 0.8 years) were tested before and after a 17-day training camp at moderate altitude. The height reached in the squat jump exercise with additional loads of 0, 25, 50, 75, and 100% of swimmers' pretest body weight and swimming start performance (time to 5, 10, and 15 m) were the dependent variables analyzed. Significant increases in the jump height (p ≤ 0.05; effect size [ES]: 0.35-0.48) and swimming start performance (p jump height before training (r = -0.56 to -0.77) and after training (r = -0.50 to -0.71). The change in the squat jump height was inversely correlated with the change in the start time at 5 m (r = -0.47), 10 m (r = -0.73), and 15 m (r = -0.62). These results suggest that altitude training can be suitable to enhance explosive performance. The correlations obtained between the squat jump height and start time in the raw and change scores confirm the relevance of having high levels of lower-body muscular power to optimize swimming start performance.

  8. Effects of altitude versus economic status on birth weight and body shape at birth.

    Science.gov (United States)

    Giussani, D A; Phillips, P S; Anstee, S; Barker, D J

    2001-04-01

    The compelling evidence linking small size at birth with later cardiovascular disease has renewed and amplified a clinical and scientific interest in the determinants of fetal growth. Although the effects of maternal nutrition on fetal growth have been extensively studied, comparatively little is known about the effects of maternofetal hypoxia. This study tested the hypothesis that in highland regions, high altitude rather than maternal economic status is associated with reduced and altered fetal growth by investigating the effects of high altitude versus economic status on birth weight and body shape at birth in Bolivia. Bolivia is geographically and socioeconomically unique. It contains several highland (>3500 m above sea level) and lowland (weight, body length, and head circumference were compared between a high- (n = 100) and low- (n = 100) income region of La Paz (3649 m; largest high-altitude city) and a high- (n = 100) and low- (n = 100) income region of Santa Cruz (437 m; largest low-altitude city). In addition, the frequency distribution across the continuum of birth weights was plotted for babies born from high- and low-income families in La Paz and Santa Cruz. Mean birth weights were lower in babies from La Paz than in babies from Santa Cruz in both high- and low-income groups. The cumulative frequency curve across all compiled birth weights was shifted to the left in babies from La Paz compared with those from Santa Cruz, regardless of economic status. The frequency of low birth weight (head circumference:birth weight ratio. These findings suggest that high altitude rather than economic status is associated with low birth weight and altered body shape at birth in babies from Bolivia. PMID:11264431

  9. Decreased plasma soluble erythropoietin receptor in high-altitude excessive erythrocytosis and Chronic Mountain Sickness.

    Science.gov (United States)

    Villafuerte, Francisco C; Macarlupú, José Luis; Anza-Ramírez, Cecilia; Corrales-Melgar, Daniela; Vizcardo-Galindo, Gustavo; Corante, Noemí; León-Velarde, Fabiola

    2014-12-01

    Excessive erythrocytosis (EE) is the hallmark of chronic mountain sickness (CMS), a prevalent syndrome in high-altitude Andean populations. Although hypoxemia represents its underlying stimulus, why some individuals develop EE despite having altitude-normal blood erythropoietin (Epo) concentration is still unclear. A soluble form of the Epo receptor (sEpoR) has been identified in human blood and competes directly for Epo with its membrane counterpart (mEpoR). Thus, reduced levels of circulating sEpoR could lead to higher Epo availability and ultimately to EE. We characterized the relationship between Epo and sEpoR, with hematocrit and hemoglobin concentration in healthy highlanders and CMS patients at 4,340 m in Cerro de Pasco, Peru. Our results show that EE patients show decreased plasma sEpoR levels and can be subdivided into two subgroups of normal and high plasma Epo concentration for the altitude of residence, with hemoglobin concentration rising exponentially with an increasing Epo-to-sEpoR ratio (Epo/sEpoR). Also, we showed that the latter varies as an inverse exponential function of arterial pulse O2 saturation. Our findings suggests that EE is strongly associated with higher Epo/sEpoR values, leading to elevated plasma Epo availability to bind mEpoR, and thereby a stronger stimulus for augmented erythropoiesis. Differences in the altitude normal and high Epo CMS patients with a progressively higher Epo/sEpoR supports the hypothesis of the existence of two genetically different subgroups suffering from EE and possibly different degrees of adaptation to chronic high-altitude hypoxia.

  10. Placental villus morphology in relation to maternal hypoxia at high altitude.

    Science.gov (United States)

    Espinoza, J; Sebire, N J; McAuliffe, F; Krampl, E; Nicolaides, K H

    2001-07-01

    Pregnancy at high altitude is associated with maternal hypoxaemic hypoxia with resultant intervillus blood hypoxia. Maternal haemoglobin concentration and blood gases were measured in pregnant women in two cities in Peru; Lima at sea level (n=18) and Cerro de Pasco at 4300 metres above sea level (n=12). Following delivery, placental sections from both groups were examined histomorphometrically using an image analysis system. Villus diameter, villus cross-sectional area, capillary diameter, capillary cross-sectional area and the percentage of villus cross-sectional area occupied by villus capillaries were calculated and parameters were compared between the two altitude groups. Maternal haemoglobin concentration and maternal blood pH were significantly higher, and maternal pO(2), pCO(2)and O(2)saturation were significantly lower in the high altitude group compared to those at sea level. The villus vessel area as a percentage of villus cross-sectional area and capillary diameter were significantly greater in the cases from the high altitude group and villus vessel area as a percentage of the villus cross-sectional area was significantly related to maternal pO(2)(r=-0.7, P=0.01), and maternal pCO(2)(r=0.7, P=0.02), but multiple regression analysis demonstrated that only pO(2)remained significantly independently associated with these villus histological findings (P=0.03). Placental terminal villi from term pregnancies at high altitude show different morphological features from pregnancies at sea level, and these changes are primarily related to maternal pO(2). The predominant morphological alteration is an increase in villus capillary diameter and therefore of the proportion of villus cross-sectional area occupied by capillary lumens.

  11. 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. PMID:25693693

  12. Peripheral blood mononuclear cell gene expression in healthy adults rapidly transported to high altitude

    Directory of Open Access Journals (Sweden)

    Herman NM

    2014-12-01

    Full Text Available Nicole M Herman,1 Diane E Grill,2 Paul J Anderson,1 Andrew D Miller,1 Jacob B Johnson,1 Kathy A O’Malley,1 Maile L Ceridon Richert,1 Bruce D Johnson1 1Department of Cardiovascular Diseases, 2Department of Biostatistics, Mayo Clinic Rochester, MN, USA Abstract: Although mechanisms of high altitude illness have been studied extensively, the processes behind the development of these conditions are still unclear. Few genome-wide studies on rapid exposure to high altitude have been performed. Each year, scientists and support workers are transferred by plane from McMurdo Station in Antarctica (sea level to the Amundsen-Scott South Pole Station at 2,835 meters. This uniform and rapid transfer to altitude provides a unique opportunity to study the effects of hypobaric hypoxia on gene expression that may help illustrate the body's adaptations to these conditions. We hypothesized that an extensive number of genes would change with rapid exposure to altitude and further expected that these genes would correspond to inflammatory pathways proposed as a mechanism in development of acute mountain sickness. Peripheral venous blood samples were drawn from 98 healthy subjects at sea level and again on day two at altitude. Microarray analysis was performed on these samples. In total, 1,118 probe sets with significant P-values and fold changes (90% upregulated were identified and entered into MetaCore™ software. Several pathways, including oxidative phosphorylation, cytoskeleton remodeling, and platelet aggregation, were significantly represented by the data set and all were upregulated. Many genes changed expression, and the vast majority of these increased. Increased metabolism in peripheral blood mononuclear cells suggests increased inflammatory activity. Keywords: peripheral blood mononuclear cells, microarray, gene expression, acute mountain sickness

  13. Standardization of Methods for Early Diagnosis and On-Site Treatment of High-Altitude Pulmonary Edema

    Directory of Open Access Journals (Sweden)

    Qiquan Zhou

    2011-01-01

    Full Text Available High-altitude pulmonary edema (HAPE is a life-threatening disease of high altitude that often affects nonacclimatized apparently healthy individuals who rapidly ascend to high altitude. Early detection, early diagnosis, and early treatment are essential to maintain the safety of people who ascend to high altitude, such as construction workers and tourists. In this paper, I discuss various methods and criteria that can be used for the early diagnosis and prediction of HAPE. I also discuss the preventive strategies and options for on-site treatment. My objective is to improve the understanding of HAPE and to highlight the need for prevention, early diagnosis, and early treatment of HAPE to improve the safety of individuals ascending to high altitude.

  14. Long-term stay at low altitude (1,200 m) promotes better hypoxia adaptation and performance.

    Science.gov (United States)

    Singh, Krishan; Gupta, R K; Soree, Poonam; Rai, Lokesh; Himashree, G

    2014-01-01

    Acute exposure to high altitude hypoxia is known to decrease physical performance. The exercise performance increases during moderate altitude training (2000-3000 m) but benefits are overshadowed by adverse effect associated with hypoxia. Therefore, the study was designed to address whether low altitude of 1200 m could increase exercise performance without any adverse effects and a correlation with stay period (stay > 6 month) was optimized. In the present study residents of lower altitude (1200 m altitude) (LA) and sea level (SL) residents were subjected to sub-maximal exercise test and their exercise response in terms of post-exercise heart rate and change in oxygen saturation was compared. Post-exercise peak heart rate (129.89 ± 13.42 vs 146.00 ± 11.81, p exercise had a significant fall (95.3 ± 2.26% vs 98 ± 0% p exercise response and hematological benefit compared to sea level residents. PMID:26215004

  15. Visual system effects of exercise on Mauna Kea at 2,200 and 4,200 meters altitude.

    Science.gov (United States)

    Schmeisser, E T; Gagliano, D L; Santiago-Marini, J

    1997-03-01

    Field exercise studies were performed at two altitudes (2,200 and 4,200 m) in 2 successive years using different sets of young male volunteers. Visual function indices were measured both at sea level and during a strenuous exercise regime at altitude. Volunteers were grouped in the first study by initial rest period (2 days vs. no rest) and in the second by diet (supplemental carbohydrates vs. Meals Ready to Eat rations only). Overall results showed no effect according to grouping, a decrease in average visual acuity at the higher altitude overall, and a decrease in electroretinographic (ERG) photopic flicker responses at moderate altitude. It is concluded that heavy exercise at these altitudes may not have operationally significant effects on ground troops in night vision or target recognition, although the change in ERG parameters does indicate a shift in retinal cone physiology that may have subtler effects.

  16. An evolutionary frame of work to study physiological adaptation to high altitudes Un marco conceptual para estudiar adaptaciones fisiológicas a altas altitudes

    Directory of Open Access Journals (Sweden)

    ENRICO L. REZENDE

    2005-06-01

    Full Text Available How complex physiological systems evolve is one of the major questions in evolutionary physiology. For example, how traits interact at the physiological and genetic level, what are the roles of development and plasticity in Darwinian evolution, and eventually how physiological traits will evolve, remains poorly understood. In this article we summarize the current frame of work evolutionary physiologists are employing to study the evolution of physiological adaptations, as well as the role of developmental and reversible phenotypic plasticity in this context. We also highlight representative examples of how the integration of evolutionary and developmental physiology, concomitantly with the mechanistic understanding of physiological systems, can provide a deeper insight on how endothermic vertebrates could cope with reduced ambient temperatures and oxygen availability characteristic of high altitude environments. In this context, high altitude offers a unique system to study the evolution of physiological traits, and we believe much can be gained by integrating theoretical and empirical knowledge from evolutionary biology, such as life-history theory or the comparative method, with the mechanistic understanding of physiological processesUna de las preguntas más importantes en fisiología evolutiva es como evolucionan los sistemas fisiológicos complejos. Por ejemplo, actualmente sabemos poco sobre la interacción entre varios rasgos a niveles genéticos y fisiológicos, sobre el papel de la plasticidad fenotípica durante distintas etapas del desarrollo y madurez para la evolución fisiológica dentro de un linaje. En este trabajo explicamos el marco conceptual ocupado por fisiólogos evolutivos en la actualidad para estudiar adaptaciones fisiológicas a nivel evolutivo y el papel de la plasticidad dentro de la evolución Darviniana. Citamos ejemplos de como la integración de la fisiología evolutiva y del desarrollo nos permitió un mayor

  17. CORRECCION DE ILUMINACION PARA IMAGENES AEREAS DE CULTIVOS TOMADAS A BAJA ALTITUD ILLUMINATION CORRECTION FOR AERIAL AGRICULTURE IMAGES TAKEN AT LOW ALTITUDE

    Directory of Open Access Journals (Sweden)

    Juan Camilo Mejía Ospina

    2007-12-01

    Full Text Available En este trabajo se propone un método para realizar correcciones de color de imágenes aéreas de cultivos tomadas a baja altitud, en diferentes fechas, horas y condiciones de nubosidad. El método no requiere que la escena posea superficies o datos concretos que sirvan de estándar para realizar la corrección sobre la iluminación presente. El está basado en la técnica de constancia de color llamada gamut mapping, a la cual se le han hecho algunas variaciones aprovechando las características propias de las imágenes aéreas. El método permite, para imágenes capturadas bajo diferentes condiciones de iluminación, su normalización de modo que sean comparables entre ellas. En particular se aplicó a plantaciones de banano, pero puede ser extendido a cualquier tipo de cultivo, siempre que se utilice fotografía aérea de baja altitud. Se probó y validó usando imágenes simuladas debido a las dificultades encontradas durante la etapa de adquisición de imágenes reales.A new method is presented in order to carry out the color corrections of aerial agriculture images taken at low altitude, in different dates, times and conditions of cloudiness. The method does not require scene targets or specific data in order to develop the correction of the actual illumination. It is based on the constancy of color technique called gamut mapping, which was adapted to take advantage of the own characteristics of the aerial images. For images captured under different conditions of illumination, the method allows its normalization for comparison purposes. It was applied to banana plantations, but it can be extended to any type of agriculture images, registered by aerial images at low altitude. It was proven and validated using synthetic images because of some difficulties found during the acquisition stage of real images.

  18. Avaliação dos efeitos da altitude sobre a visão Analysis of vision effects at altitude

    Directory of Open Access Journals (Sweden)

    Luiz Filipe de Albuquerque Alves

    2008-10-01

    Full Text Available Este trabalho de revisão bibliográfica é direcionado para a investigação dos efeitos da hipóxia da altitude sobre a visão. Pretende assim, ser uma contribuição na identificação dos sinais e sintomas presentes durante a exposição do aeronavegante às altas altitudes. O conhecimento sobre as características da atmosfera terrestre e o comportamento dos gases quando submetidos à variação de pressão atmosférica são muito importantes para o correto diagnóstico dos disbarismos, hipóxia e doença da descompressão para os profissionais de saúde voltados para a atividade aeroespacial. O ambiente atmosférico a que os aeronavegantes são expostos, é capaz de interferir de forma significativa na função visual, podendo gerar lesões de caráter reversíveis ou não, tais como: hemorragias retinianas, diminuição da visão noturna e da acuidade visual, restrição do campo visual, aparecimento de estrabismos latentes, diminuição da pressão intra-ocular e alterações refracionais em indivíduos previamente submetidos às cirurgias refrativas.This bibliographic review work is pointed to the effects of altitude hypoxia on sight. It intends to contribute for the identification of signs and symptoms of hypoxia during high altitude exposition. The understanding of the terrestrial atmosphere and the laws of physics related to gas behavior under atmospheric pressure variation are very important for the correct diagnosis of the dysbarisms, hypoxia, decompression disease and others, by the aerospace health professionals. The atmospheric environment that pilots are exposed is able to interfere in a significant way on visual function and can lead to reversible or irreversible lesions such as: retinal bleeding, decrease of the night vision and vision acuity, restriction of the visual field, emergence of latent strabismus, decrease of the intra-ocular pressure and refractive alterations in individuals that went through refractive surgery.

  19. Modeling of High-altitude Atmospheric Dispersion Using Climate and Meteorological Forecast Data

    Energy Technology Data Exchange (ETDEWEB)

    Glascoe, L G; Chin, H S

    2005-03-30

    The overall objective of this study is to provide a demonstration of capability for importing both high altitude meteorological forecast and climatological datasets from NRL into the NARAC modeling system to simulate high altitude atmospheric droplet release and dispersion. The altitude of release for the proposed study is between 60 and 100km altitude. As either standard climatological data (over a period of 40 years) or daily meteorological forecasts can drive the particle dispersion model, we did a limited comparison of simulations with meteorological data and simulations with climatological data. The modeling tools used to address this problem are the National Atmospheric Release Advisory Center (NARAC) modeling system at LLNL which are operationally employed to assist DOE/DHS/DOD emergency response to an atmospheric release of chemical, biological, and radiological contaminants. The interrelation of the various data feeds and codes at NARAC are illustrated in Figure 1. The NARAC scientific models are all verified to both analytic solutions and other codes; the models are validated to field data such as the Prairie Grass study (Barad, 1958). NARAC has multiple real-time meteorological data feeds from the National Weather Service, from the European Center for Medium range Weather Forecasting, from the US Navy, and from the US Air Force. NARAC also keeps a historical archive of meteorological data partially for research purposes. The codes used in this effort were the Atmospheric Data Assimilation and Parameterization Techniques (ADAPT) model (Sugiyama and Chan, 1998) and a development version of the Langrangian Operational Dispersion Integrator (LODI) model (Nasstrom et al., 2000). The use of the NASA GEOS-4 dataset required the use of a development version of the Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS) model (Hodur, 1997; Chin and Glascoe, 2004). The specific goals of this study are the following: (1) Confirm data compatibility of NRL

  20. AUMENTO DEL ÍNDICE SOLAR ULTRAVIOLETA CON LA ALTURA SOLAR ULTRAVIOLET INDEX INCREASE WITH ALTITUDE

    Directory of Open Access Journals (Sweden)

    Miguel Rivas A

    2008-09-01

    Full Text Available En este trabajo se presentan los resultados obtenidos al realizar comparaciones entre mediciones experimentales de Índice solar ultravioleta (IUV obtenido a partir de datos experimentales y también de resultados teóricos proveniente del cálculo del IUV mediante el modelo TUV (modelo ultravioleta troposféricol. En especial se destacan los aumentos de la irradianza solar ultravioleta B (UVB 280-320 nm que se reciben a nivel del suelo debido a los aumentos de la altitud del lugar sobre el nivel del mar (efecto altitudinal. Los cálculos mediante el modelo TUV se realizaron en un período comprendido entre los años 1996-2003, introduciendo los parámetros de los lugares geográficos en que se hicieron las mediciones experimentales. Dado que una de las variables importantes de la que depende el IUV es la altitud sobre el nivel del mar y considerando que la zona norte de Chile es un lugar con características especiales para realizar este tipo de estudios, es que se han realizado experimentos para medir la irradianza solar UVB entre 0-3.200 m de altura, y a partir de estos datos se ha obtenido el IUV. La importancia de estos resultados radica en el hecho que a partir de ellos se pueden cuantificar el incremento de la irradianza UVB por cada 1.000 m de altitud sobre el nivel del mar. Un número creciente de personas se desplazan continuamente entre el nivel del mar y altitudes cercanas a los 5.000 m, debido a trabajos relacionados con: minería, turismo, transporte. En todos estos casos estas personas reciben importantes incrementos de irradianza solar UV, que pueden afectar gravemente su salud si no se informan de los riesgos para que puedan tomar precauciones.In this work we present results from ultraviolet solar index (IUV comparisons between values obtained from experimental measurements, with theoretical results obtained from tropospherical ultraviolet model (TUV. It is important to emphasise the observed increase in solar ultraviolet B (UVB

  1. Cerebrovascular responses to hypoxia and hypocapnia in high-altitude dwellers.

    Science.gov (United States)

    Norcliffe, L J; Rivera-Ch, M; Claydon, V E; Moore, J P; Leon-Velarde, F; Appenzeller, O; Hainsworth, R

    2005-07-01

    Cerebral blood flow is known to increase in response to hypoxia and to decrease with hypocapnia. It is not known, however, whether these responses are altered in high-altitude dwellers who are not only chronically hypoxic and hypocapnic, but also polycythaemic. Here we examined cerebral blood flow responses to hypoxia and hypocapnia, separately and together, in Andean high-altitude dwellers, including some with chronic mountain sickness (CMS), which is characterized by excessive polycythaemia. Studies were carried out at high altitude (Cerro de Pasco (CP), Peru; barometric pressure (P(B)) 450 mmHg) and repeated, following relief of the hypoxia, on the day following arrival at sea level (Lima, Peru; P(B) 755 mmHg). We compared these results with those from eight sea-level residents studied at sea level. In nine high-altitude normal subjects (HA) and nine CMS patients, we recorded middle cerebral artery mean blood flow velocity (MCAVm) using transcranial Doppler ultrasonography, and expressed responses as changes from baseline. MCAVm responses to hypoxia were determined by changing end-tidal partial pressure of oxygen (P(ET,O2)) from 100 to 50 mmHg, with end-tidal partial pressure of carbon dioxide clamped. MCAVm responses to hypocapnia were studied by voluntary hyperventilation with (P(ET,O2)) clamped at 100 and 50 mmHg. There were no significant differences between the cerebrovascular responses of the two groups to any of the interventions at either location. In both groups, the MCAVm responses to hypoxia were significantly greater at Lima than at CP (HA, 12.1 +/- 1.3 and 6.1 +/- 1.0%; CMS, 12.5 +/- 0.8 and 5.6 +/- 1.2%; P < 0.01 both groups). The responses at Lima were similar to those in the sea-level subjects (13.6 +/- 2.3%). The responses to normoxic hypocapnia in the altitude subjects were also similar at both locations and greater than those in sea-level residents. During hypoxia, both high-altitude groups showed responses to hypocapnia that were

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

    International Nuclear Information System (INIS)

    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

  3. 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

  4. Data catalog series for space science and applications flight missions. Volume 2A: Descriptions of geostationary and high-altitude scientific spacecraft and investigations

    Science.gov (United States)

    Hills, H. K. (Editor); Littlefield, R. G. (Editor); Schofield, N. J. (Editor); Vetts, J. I. (Editor)

    1982-01-01

    Data from Earth-orbiting spacecraft at geostationary and higher altitudes was cataloged. Three lunar-orbiting spacecraft and some others whose apogees did not attain the geostationary altitude are included.

  5. Estudio del Efecto de la Altitud sobre el Comportamiento de Motores de Combustión Interna. Parte 1: Funcionamiento Study of the Altitude Effect on Internal Combustion Engine Operation. Part 1: Performance

    OpenAIRE

    Magín Lapuerta; Octavio Armas; John R Agudelo; Carlos A. Sánchez

    2006-01-01

    En este trabajo se estudia el efecto de la altitud sobre la potencia en motores de aspiración natural y turbosobrealimentados sin sistemas correctores, en función de la presión ambiental. La altitud sobre el nivel del mar tiene un notable efecto sobre la densidad del aire y su composición. Dado que los motores de combustión interna tienen sistemas de admisión y de inyección de combustible volumétricos, la altitud modifica el ciclo termodinámico de operación, y en consecuencia las prestaciones...

  6. High serum zinc and serum testosterone levels were associated with excessive erythrocytosis in men at high altitudes.

    Science.gov (United States)

    Gonzales, Gustavo F; Tapia, Vilma; Gasco, Manuel; Rubio, Julio; Gonzales-Castañeda, Cynthia

    2011-12-01

    Chronic mountain sickness (CMS), a lack of adaptation to altitude characterized by excessive erythrocytosis (EE), is a health problem associated with life at high altitude. The erythropoietic process is regulated by both erythropoietin and testosterone. Zinc (Zn) is known to be related with testosterone and hemoglobin levels; meanwhile, nitric oxide was also associated with adaptation to high altitude. The aim of this study was to determine the relationship of hemoglobin and CMS score with serum levels of zinc, total testosterone (TT), calculated free testosterone (cFT), bioavailable testosterone (BAT), hemoglobin, and nitric oxide in men at high altitude with or without EE. Men residing in Lima (150 m) and Cerro de Pasco (4,340 m), Peru, were divided into three groups: (1) low altitude, (2) high altitude without EE (hemoglobin < 21 g/dl), and (3) high altitude with EE (hemoglobin ≥ 21 g/dl). Adjusted multivariable regression models showed that serum testosterone (total or free) and Zn levels were independently correlated with increased hemoglobin levels. Similarly, hemoglobin was positively related with signs/symptoms of CMS; however, both increased the serum Zn and the nitric oxide levels correlated with reduced risk for signs/symptoms of CMS. In conclusion, higher serum testosterone levels and Zn levels were associated with EE, and low scores of signs/symptoms of CMS were associated with higher Zn and nitric oxide levels.

  7. Aerosol contents at an altitude of ~2 km in central Himalayas

    CERN Document Server

    Sagar, R; Pant, P; Dumka, U C; Moorthy, K K; Sridharan, R; Sagar, Ram

    2002-01-01

    Aerosols, both natural and anthropogenic, play an important role in the atmospheric science, by imparting radiative forcing and perturbing the radiative balance of the Earth atmosphere system as well as by degrading the environment. To understand the effect of aerosols on our geo/biosphere system, it is essential to characterize their physical and chemical properties regionally because of the regional nature of their properties and the short lifetime. As most of the aerosol sources are of terrestrial origin the variability of their properties will be very large close to the surface. At higher altitudes, above the mixing region, and in the free troposphere, the aerosol characteristics have a more synoptic perspective; would be indicative of the background level and are useful to understand long-term impacts. Such systematic measurements of aerosols at high altitudes are practically non-existing in India. Realising the potential and need for such studies, an activity has been initiated at Manora Peak, Nainital ...

  8. High Diversity of Drosophilidae in High-Altitude Wet Forests in Northeastern Brazil.

    Science.gov (United States)

    Monteiro, L S; Garcia, A C L; Oliveira, G F; Rohde, C

    2016-06-01

    The high-altitude wet forests of northeastern Brazil, locally known as "Brejos de Altitude," are enclaves of the Atlantic Forest situated above 500 m, surrounded by dryland vegetation, the Caatinga. The aim of this study was to characterize drosophilid communities in these upland forests, since few ecological studies on drosophilid communities have been conducted in northeastern Brazil. Four sites were investigated in three different times of the year throughout standardized traps. The results reveal the presence of 55 different species in a total of 13,064 specimens collected. The data were evaluated using ecological diversity measurements and compared with those obtained for other environments in the same geographic region. As for species composition, the Bonito upland forest, in a boundary forest location, stood out as having high species richness. PMID:26957082

  9. Contribution of Neutron Beta Decay to Radiation Belt Pumping from High Altitude Nuclear Explosion

    Energy Technology Data Exchange (ETDEWEB)

    Marrs, R

    2002-11-13

    In 1962, several satellites were lost following high altitude nuclear tests by the United States and the Soviet Union. These satellite failures were caused by energetic electrons injected into the earth's radiation belts from the beta decay of bomb produced fission fragments and neutrons. It has been 40 years since the last high altitude nuclear test; there are now many more satellites in orbit, and it is important to understand their vulnerability to radiation belt pumping from nuclear explosions at high altitude or in space. This report presents the results of a calculation of the contribution of neutron beta decay to artificial belt pumping. For most high altitude nuclear explosions, neutrons are expected to make a smaller contribution than fission products to the total trapped electron inventory, and their contribution is usually neglected. However, the neutron contribution may dominate in cases where the fission product contribution is suppressed due to the altitude or geomagnetic latitude of the nuclear explosion, and for regions of the radiation belts with field lines far from the detonation point. In any case, an accurate model of belt pumping from high altitude nuclear explosions, and a self-consistent explanation of the 1962 data, require inclusion of the neutron contribution. One recent analysis of satellite measurements of electron flux from the 1962 tests found that a better fit to the data is obtained if the neutron contribution to the trapped electron inventory was larger than that of the fission products [l]. Belt pumping from high altitude nuclear explosions is a complicated process. Fission fragments are dispersed as part of the ionized bomb debris, which is constrained and guided by the earth's magnetic field. Those fission products that beta decay before being lost to the earth's atmosphere can contribute trapped energetic electrons to the earth's radiation belts. There has been a large effort to develop computer models for

  10. The Eddy Experiment: accurate GNSS-R ocean altimetry from low altitude aircraft

    CERN Document Server

    Ruffini, G; Caparrini, M; Germain, O; Martin-Neira, M

    2004-01-01

    During the Eddy Experiment, two synchronous GPS receivers were flown at 1 km altitude to collect L1 signals and their reflections from the sea surface for assessment of altimetric precision and accuracy. Wind speed (U10) was around 10 m/s, and SWH up to 2 m. A geophysical parametric waveform model was used for retracking and estimation of the lapse between the direct and reflected signals with a 1-second precision of 3 m. The lapse was used to estimate the SSH along the track using a differential model. The RMS error of the 20 km averaged GNSS-R absolute altimetric solution with respect to Jason-1 SSH and a GPS buoy measurement was of 10 cm, with a 2 cm mean difference. Multipath and retracking parameter sensitivity due to the low altitude are suspected to have degraded accuracy. This result provides an important milestone on the road to a GNSS-R mesoscale altimetry space mission.

  11. Operating Water Cherenkov Detectors in high altitude sites for the Large Aperture GRB Observatory

    CERN Document Server

    Allard, D; Asorey, H; Barros, H; Bertou, X; Castillo, M; Chirinos, J M; De Castro, A; Flores, S; González, J; Berisso, M Gomez; Grajales, J; Guada, C; Day, W R Guevara; Ishitsuka, J; López, J A; Martínez, O; Melfo, A; Meza, E; Loza, P Miranda; Barbosa, E Moreno; Murrugarra, C; Núñez, L A; Ormachea, L J Otiniano; Pérez, G; Perez, Y; Ponce, E; Quispe, J; Quintero, C; Rivera, H; Rosales, M; Rovero, A C; Saavedra, O; Salazar, H; Tello, J C; Peralda, R Ticona; Varela, E; Velarde, A; Villaseñor, L; Wahl, D; Zamalloa, M A

    2009-01-01

    Water Cherenkov Detectors (WCD) are efficient detectors for detecting GRBs in the 10 GeV - 1 TeV energy range using the single particle technique, given their sensitivity to low energy secondary photons produced by high energy photons when cascading in the atmosphere. The Large Aperture GRB Observatory (LAGO) operates arrays of WCD in high altitude sites (above 4500 m a.s.l.) in Bolivia, Mexico and Venezuela, with planned extension to Peru. Details on the operation and stability of these WCD in remote sites with high background rates of particles will be detailed, and compared to simulations. Specific issues due to operation at high altitude, atmospheric effects and solar activity, as well as possible hardware enhancements will also be presented.

  12. The effects of high altitude on age at menarche and menopause

    Science.gov (United States)

    Kapoor, A. K.; Kapoor, Satwanti

    1986-03-01

    The age at menarche and menopause of three groups of Bhotia females living at high altitude, Himalayan region — Uttar Pradesh, North India, were studied. The Johari Bhotia women had earliest menarche (¯X=15.1±1.1 years) as compared to Rang Bhotias, settled (¯X=15.6±0.9 years) and Rang Bhotias, migratory (¯X=16.0±1.0 years). The differences between all these three groups for age at menarche were significant. A trend towards increase in age at menarche with an increase in altitude has been observed, but the total fertility period in the three groups remained similar as early menarche has been found to be associated with early onset of menopause and late menarche with late menopause.

  13. Sensitivity of the High Altitude Water Cherenkov Experiment to observe Gamma-Ray Bursts

    Science.gov (United States)

    González, M. M.

    Ground based telescopes have marginally observed very high energy emission (>100GeV) from gamma-ray bursts(GRB). For instance, Milagrito observed GRB970417a with a significance of 3.7 sigmas over the background. Milagro have not yet observed TeV emission from a GRB with its triggered and untriggered searches or GeV emission with a triggered search using its scalers. These results suggest the need of new observatories with higher sensitivity to transient sources. The HAWC (High Altitute Water Cherenkov) observatory is proposed as a combination of the Milagro tecnology with a very high altitude (>4000m over see level) site. The expected HAWC sensitivity for GRBs is at least >10 times the Milagro sensitivity. In this work HAWC sensitivity for GRBs is discussed for different detector configurations such as altitude, distance between PMTs, depth under water of PMTs, number of PMTs required for a trigger, etc.

  14. Reference energy-altitude descent guidance: Simulator evaluation. [aircraft descent and fuel conservation

    Science.gov (United States)

    Abbot, K. H.; Knox, C. E.

    1985-01-01

    Descent guidance was developed to provide a pilot with information to ake a fuel-conservative descent and cross a designated geographical waypoint at a preselected altitude and airspeed. The guidance was designed to reduce fuel usage during the descent and reduce the mental work load associated with planning a fuel-conservative descent. A piloted simulation was conducted to evaluate the operational use of this guidance concept. The results of the simulation tests show that the use of the guidance reduced fuel consumption and mental work load during the descent. Use of the guidance also decreased the airspeed error, but had no effect on the altitude error when the designated waypoint was crossed. Physical work load increased with the use of the guidance, but remained well within acceptable levels. The pilots found the guidance easy to use as presented and reported that it would be useful in an operational environment.

  15. LOLAS: an optical turbulence profiler in the atmospheric boundary layer with extreme altitude-resolution

    CERN Document Server

    Avila, R; Wilson, R W; Chun, M; Butterley, T; Carrasco, E

    2008-01-01

    We report the development and first results of an instrument called Low Layer Scidar (LOLAS) which is aimed at the measurement of optical-turbulence profiles in the atmospheric boundary layer with high altitude-resolution. The method is based on the Generalized Scidar (GS) concept, but unlike the GS instruments which need a 1- m or larger telescope, LOLAS is implemented on a dedicated 40-cm telescope, making it an independent instrument. The system is designed for widely separated double-star targets, which enables the high altitude-resolution. Using a 20000-separation double- star, we have obtained turbulence profiles with unprecedented 12-m resolution. The system incorporates necessary novel algorithms for autoguiding, autofocus and image stabilisation. The results presented here were obtained at Mauna Kea Observatory. They show LOLAS capabilities but cannot be considered as representative of the site. A forthcoming paper will be devoted to the site characterisation. The instrument was built as part of the ...

  16. Exercise capacity and selected physiological factors by ancestry and residential altitude

    DEFF Research Database (Denmark)

    Bianba; Berntsen, Sveinung; Andersen, Lars Bo;

    2014-01-01

    (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...... m) participated in two cross-sectional studies. The maximal power output (W max) was assessed using an ergometer cycle. RESULTS: Lhasa Tibetan children had a 20% higher maximal power output (watts/kg) than Tingri Tibetan and 4% higher than Lhasa Han Chinese. Maximal heart rate, arterial oxygen...... level) and across ancestry (native Tibetan vs. Han Chinese children living at the same altitude of 3700 m). METHODS: A total of 430 9-10-year-old native Tibetan children from Tingri (4300 m) and 406 native Tibetan- and 406 Han Chinese immigrants (77% lowland-born and 33% highland-born) from Lhasa (3700...

  17. Geomagnetic field and altitude effects on the performance of future IACT arrays

    CERN Document Server

    Szanecki, M; Sobczyńska, D; Niedźwiecki, A; Sitarek, J; Bednarek, W

    2014-01-01

    The performance of IACT's arrays is sensitive to the altitude and geomagnetic field (GF) of the observatory site. Both effects play important role in the region of the sub-TeV gamma-ray measurements. We investigate the influence of GF on detection rates and the energy thresholds for five possible locations of the future CTA observatory using the Monte Carlo simulations. We conclude that the detection rates of gamma rays and the energy thresholds of the arrays can be fitted with linear functions of the altitude and the component of the GF perpendicular to the shower axis core. These results can be directly extrapolated for any possible localization of the CTA. In this paper we also show the influence of both geophysical effects on the images of shower and gamma/hadron separation.

  18. Discovery of C4 species at high altitude in Qinghai-Tibetan Plateau

    Institute of Scientific and Technical Information of China (English)

    WANG Luo; L(U) Houyuan; WU Naiqin; CHU Duo; HAN Jiamao; WU Yuhu; WU Haibin; GU Zhaoyan

    2004-01-01

    Plant specimens are collected from the areas between latitude 27°42'N and 40°57'N, and longitude 88°93'E and 103°24'E, with an altitudinal range from 2210 to 5050 m above the sea level in Qinghai-Tibetan Plateau. The stable carbon isotope analysis indicates that two of Chenopodiaceae and six of Poaceae in the samples are C4 plants. Four of the C4 plants are found in 11 spots with altitudes above 3800 m,and Pennisetum centrasiaticum, Arundinella yunnanensis and Orinus thoroldii are present in six spots above 4000 m, even up to 4520 m. At low CO2 partial pressure, that sufficient energy of high light improving C4 plant's tolerance of low temperature and precipitations concentrating in growing season probably are favorable for C4 plants growing at high altitude in Qinghai-Tibetan Plateau.

  19. Study of the Floristic Biodiversity Available on Permanent Pastures Located at Different Altitude Levels

    Directory of Open Access Journals (Sweden)

    Dorin Rechiţean

    2011-10-01

    Full Text Available The researches carried out between the altitude levels of 236 and 1300 m, in 13 localities from Banat Mountains, proved the influence exerted by stationary natural conditions on the botanic diversity of the vegetal cover. From one vegetal association to another, the total number of botanic species ranged between 9 and 21; the biggest number of species was recorded between 236 – 630 m altitude, and the smallest one between 462 – 650 m. The mean coverage degree of these species was 42.69% in the species belonging to the Poaceae Family (with a variation of 30-70% and 12.85% in the species belonging to the Fabaceae Family (variation of 25-65%.

  20. Disturbances in the lower ionosphere caused by a low altitude nuclear explosion

    Science.gov (United States)

    Xunjie, Zhang; Xueqin, Ruan; Wenzhen, Wang

    1995-03-01

    Observations of the lower ionospheric disturbance caused by a low altitude nuclear explosion are presented. A forward scatter radar, frequency 41 MHz, power 2.5 kW, was used to study these disturbances. The first radar scattering signal consisting of three peaks appeared 40 s after the explosion. It was due to early ionization by delayed gamma rays. The second kind of disturbance generated after 190 s was clearly different from the first. The scattering signal had a constant component which indicated a strong specular reflection. The field strength increased by more than 20 db. This disturbance was produced by the direct shock wave. The third kind of disturbance began after 8 min, lasted 5.0 min, and was probably dominated by the fireball/smoke cloud oscillation when it reached its stabilization altitude and approached hydrodynamical equilibrium with the ambient atmosphere. Using numerical computation techniques, we have explained the above results well.

  1. Unmanned Aerial System (UAS) Traffic Management (UTM): Enabling Low-Altitude Airspace and UAS Operations

    Science.gov (United States)

    Kopardekar, Parimal H.

    2014-01-01

    Many civilian applications of Unmanned Aerial Systems (UAS) have been imagined ranging from remote to congested urban areas, including goods delivery, infrastructure surveillance, agricultural support, and medical services delivery. Further, these UAS will have different equipage and capabilities based on considerations such as affordability, and mission needs applications. Such heterogeneous UAS mix, along with operations such as general aviation, helicopters, gliders must be safely accommodated at lower altitudes. However, key infrastructure to enable and safely manage widespread use of low-altitude airspace and UAS operations therein does not exist. Therefore, NASA is exploring functional design, concept and technology development, and a prototype UAS Traffic Management (UTM) system. UTM will support safe and efficient UAS operations for the delivery of goods and services

  2. THE CHANGES OF IL-1β AND IL-6 LEVEL AT DIFFERENT ALTITUDE AND THEIR SIGNIFICANCE

    Institute of Scientific and Technical Information of China (English)

    Jia Mian; Geng Paili; Zhu Haihong; Wu Hongfu

    2006-01-01

    Objective To investigate the changes of the concentration of interkeukine β 1(IL-1β) and Interleukine 6(IL-6) in the serum of the people who live in the different altitude, and try to find the relation between the cytokines (CK) and the hypoxia adaptation and some diseases caused by hypoxia. Methods Using enzyme linked immunoabsorbent assay (ELISA) to detect the level of the concentration of IL-1β and IL-6 in the serum. Results The concentration of IL-1β showed significant increase in values (P<0.05) at 4050m. IL-6 in same altitude showed obvious changes as well (P<0.05). Conclusion The results showed that the concentration of IL-1β and IL-6 have significant changes in the serum. This means that they may be involved in the process of the adaptation and some sickness because of hypoxia.

  3. Cosmic-radiation dosimetry using electronic personal dosemeter (EPD) at commercial aircraft altitude

    International Nuclear Information System (INIS)

    Electronic Personal Dosemeter (EPD) was examined for effectiveness in cosmic radiation dosimetry at aircraft altitude through the measurements in a Japan-US round trip. The EPD value (Hepd) of individual dose equivalent, penetrating, Hp(10), was considered to be almost equal the deep absorbed dose attributed to electrons at the aircraft altitude. By assuming the fractions and the effective quality factors for other components (muons, protons, and neutrons) based on model-calculation data, an empirical equation to estimate a conservative deep dose-equivalent at 5 cm-tissue depth, H(50), was given as H(50)=3.1 x Hepd. Estimated H(50) values in the international flights were 4.9 μSv h-1 from Tokyo to New York and 3.6 μSv h-1 from Los Angeles to Tokyo. These values agreed well with the predicted values presented by NCRP. (author)

  4. Sperm forward motility is negatively affected by short-term exposure to altitude hypoxia.

    Science.gov (United States)

    Verratti, V; Di Giulio, C; D'Angeli, A; Tafuri, A; Francavilla, S; Pelliccione, F

    2016-09-01

    Human exposure to altitude is a model to study the role of oxygen in different areas of physiology and pathophysiology. The aim of this study was to evaluate whether a short exposure to hypoxia (5 days) combined with exercise, at altitude ranging from 900 m above sea level to 5895 m above sea level (Kilimanjaro Expedition) can modify seminal and reproductive hormonal parameter levels in human beings. During the ascent, blood oxygen saturation at 3.848 m above sea level was found to be decreased when compared to sea level (P hypoxia on spermatozoa during the epididymal transit where they mature acquiring their motility. PMID:26762696

  5. Aeroassisted transfer between coplanar elliptical orbits during near constant altitude coasting

    Science.gov (United States)

    Taratuta, Aba; Mishne, David; Gur, Ilana

    An aeroassisted transfer between coplanar elliptical orbits is presented. The maneuver consists of three thrust impulses and a coast flight in the atmosphere. Several control strategies for the atmospheric coast are analyzed: constant altitude coast, constant velocity glide, constant heating rate coast. For each control strategy, the optimal altitude is chosen. The criterion for the maneuver efficiency was the amount of fuel consumption for a given rotation angle, subject to a heating rate limit. The results are compared with aeroassisted multipass maneuver and aeroassisted drag-only maneuver. It was shown that the coast maneuver extends the region in which the lift-controlled aeroassisted maneuver is superior to other maneuvers. Numerical examples are presented.

  6. 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.

  7. High-altitude gastrointestinal bleeding: An observation in Qinghai-Tibetan railroad construction workers on Mountain Tanggula

    Institute of Scientific and Technical Information of China (English)

    Tian-Yi Wu; Shou-Quan Ding; Jin-Liang Liu; Jian-Hou Jia; Rui-Chen Dai; Dong-Chun Zhu; Bao-Zhu Liang; De-Tang Qi; Yong-Fu Sun

    2007-01-01

    AIM: To investigate the gastrointestinal bleeding (GIB) in people from lowland to high altitude and in workers on Mountain Tanggula and its causes as well as treatment and prophylaxis.METHODS: From 2001 to October 2003, we studied GIB in 13 502 workers constructing the railroad on Mountain Tanggula which is 4905 m above the sea level. The incidence of GIB in workers at different altitudes was recorded. Endoscopy was performed when the workersevacuated to Golmud (2808 m) and Xining (2261 m).The available data on altitude GIB were analyzed.RESULTS: The overall incidence of GIB was 0.49% in 13502 workers. The incidence increased with increasing altitude. The onset of symptoms in most patients was within three weeks after arrival at high altitude. Bleeding manifested as hematemesis, melaena or hematochezia,and might be occult. Endoscopic examination showed that the causes of altitude GIB included hemorrhage gastritis, gastric ulcer, duodenal ulcer, and gastric erosion. Experimental studies suggested that acute gastric mucosal lesion (AGML) could be induced by hypoxic and cold stress, which might be the pathogenesis of altitude GIB. Those who consumed large amount of alcohol, aspirin or dexamethasone were at a higher risk of developing GIB. Persons who previously suffered from peptic ulcer or high-altitude polycythemia were also at risk of developing GIB. Early diagnosis, evacuation, and treatment led to early recovery.CONCLUSION: GIB is a potentially life threatening disease, if it is not treated promptly and effectively. Early diagnosis, treatment and evacuation lead to an early recovery. Death due to altitude GIB can be avoided if early symptoms and signs are recognized.

  8. Bird migration flight altitudes studied by a network of operational weather radars

    OpenAIRE

    Dokter, Adriaan M.; Liechti, Felix; Stark, Herbert; Delobbe, Laurent; Tabary, Pierre; Holleman, Iwan

    2010-01-01

    A fully automated method for the detection and quantification of bird migration was developed for operational C-band weather radar, measuring bird density, speed and direction as a function of altitude. These weather radar bird observations have been validated with data from a high-accuracy dedicated bird radar, which was stationed in the measurement volume of weather radar sites in The Netherlands, Belgium and France for a full migration season during autumn 2007 and spring 2008. We show tha...

  9. Exercise at simulated high altitude facilitates the increase in capillarity in skeletal muscle of rats

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    AIM: To study the changes in capillarity of skeletal muscle during acclimation to high altitude, and explore the effects of a certain extent physical activity under hypoxia on capillary formation and the role of vascular endothelial growth factor (VEGF) in this process. METHODS: 48 Wistar rats were divided into 3 groups: Ⅰ normoxic control; Ⅱ hypoxia and Ⅲ hypoxia+exercise. Rats of Ⅱ and Ⅲ groups were subjected to hypobaric hypoxia for 5 weeks (23 h/d). They were first brought to simulated 4 000 m altitude, where rats of the Ⅲgroup were forced to swim for 1 h/d (6 d/week). Then the animals were ascent to 5 000 m. Biomicrosphere method was used to determine blood flow of skeletal muscle. The mean fiber cross-sectional area (FCSA), capillary density (CD) and capillary/fiber ratio (C/F) of red portion of the lateral head of the gastrocneminus were assayed by myofibrillar ATPase histochemistry. VEGF and its receptor KDR were assayed with immunohistochemistry method.RESULTS: By comparison with the normoxic control, 5-week hypoxic exposure resulted in a decrease in cross-sectional area of skeletal muscle fiber and an increase in CD, but the C/F remained unchanged. The blood supply to the gastrocnemius was not changed. After 5-week-exercise at high altitude, the muscle fibers did not undergo atrophy. CD, C/F, and the blood flow at rest increased significantly. VEGF protein was found primarily in the matrix between muscle fibers; KDR were shown mainly in endothelial cells of capillary. VEGF was more strongly stained in the skeletal muscle of hypoxia-exercise rats.CONCLUSION: Hypoxia itself can not induce neovascularization. While exercise during hypoxic exposure can lead to capillary formation. VEGF and KDR may play roles in it. New capillary formation benefits the blood supply, oxygen delivery and working performance at high altitude.

  10. First space-borne measurements of the altitude distribution of mesospheric magnesium species

    Directory of Open Access Journals (Sweden)

    M. Scharringhausen

    2007-04-01

    Full Text Available We present a joint retrieval as well as first results for mesospheric air density and mesospheric Magnesium species (Mg and Mg+ using limb data from the SCIAMACHY instrument on board the European ENVISAT satellite.

    Metallic species like neutral Mg, ionized Mg+ and others (Fe, Si, Li, etc. ablate from meteoric dust, enter the gas phase and occur at high altitudes (≥70 km. Emissions from these species are clearly observed in the SCIAMACHY limb measurements. These emissions are used to retrieve total and thermospheric column densities as well as altitude-resolved profiles of metallic species in the altitude range of 70–92 km. In this paper, neutral Magnesium as well as its ionized counterpart Mg+ is considered. These species feature resonance fluorescence in the wavelength range 279 and 285 nm and thus have a rather simple excitation process.

    A radiative transfer model (RTM for the mesosphere has been developed and validated. Based on a ray tracing kernel, radiances in a large wavelength range from 240–300 nm covering limb as well as nadir geometry can be calculated. The forward model has been validated and shows good agreement with established models in the given wavelength range and a large altitude range.

    The RTM has been coupled to a retrieval based on Optimal Estimation. Air density is retrieved from Rayleigh backscatter light. Mesospheric Mg and Mg+ number densities are retrieved from their emission signals observed in the limb scans of SCIAMACHY. Other species like iron, silicon, OH and NO can be investigated in principle with the same algorithm. Based on the retrieval presented here, SCIAMACHY offers the opportunity to investigate mesospheric species on a global scale and with good vertical resolution for the first time.

  11. An appraisal of precipitation distribution in the high-altitude catchments of the Indus basin

    OpenAIRE

    Dahri, Z.H.; Ludwig, F.; E. Moors; Ahmad, B.; A. Khan; P. Kabat

    2016-01-01

    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 the accumulation zones of major glaciers to analyse altitudinal dependency of precipitation in the...

  12. Development of Ultra-Thin Polyethylene Balloons for High Altitude Research upto Mesosphere

    Science.gov (United States)

    Kumar, B. Suneel; Nagendra, N.; Ojha, D. K.; Peter, G. Stalin; Vasudevan, R.; Anand, D.; Kulkarni, P. M.; Reddy, V. Anmi; Rao, T. V.; Sreenivasan, S.

    Ever since its inception four decades back, Balloon Facility of Tata Institute of Fundamental Research (TIFR), Hyderabad has been functioning with the needs of its user scientists at its focus. During the early nineties, when the X-ray astronomy group at TIFR expressed the need for balloons capable of carrying the X-ray telescopes to altitudes up to 42 km, the balloon group initiated research and development work on indigenous balloon grade films in various thickness not only for the main experiment but also in parallel, took up the development of thin films in thickness range 5 to 6 μm for fabrication of sounding balloons required for probing the stratosphere up to 42 km as the regular 2000-gram rubber balloon ascents could not reach altitudes higher than 38 km. By the year 1999, total indigenization of sounding balloon manufacture was accomplished. The work on balloon grade ultra-thin polyethylene film in thickness range 2.8 to 3.8 μm for fabrication of balloons capable of penetrating mesosphere to meet the needs of user scientists working in the area of atmospheric dynamics commenced in 2011. Pursuant to the successful trials with 61,000-m3 balloon made of 3.8-μm Antrix film reaching stratopause (48 km) for the first time in the history of balloon facility in the year 2012, fine tuning of launch parameters like percentage free lift was carried out to take the same volume balloons to higher mesospheric altitudes. Three successful flights with a total suspended load of 10 kg using 61,000-m3 balloons were carried out in the month of January 2014 and all the three balloons crossed into the mesosphere reaching altitudes of over 51 km. All the balloons flown so far are closed system with no escape ducts. Balloon fabrication, development of launch hardware, flight control instruments and launch technique for these mesospheric balloon flights are discussed in this paper.

  13. High-altitude alpine therapy and lung function in asthma: systematic review and meta-analysis

    Directory of Open Access Journals (Sweden)

    Denis Vinnikov

    2016-06-01

    Full Text Available We used meta-analysis to measure the effect of high-altitude climate therapy (HACT on lung function outcomes in asthma, and systematically searched PubMed, Embase and www.elibrary.ru for publications appearing from 1970 to mid-2015. We included studies carried out with children or adults with an exposure of up to 12 weeks at an altitude of ≥1500 m above sea level. Changes in forced expiratory volume in 1 s (FEV1, FEV1/vital capacity ratio or peak expiratory flow rate as the HACT intervention outcomes were analysed. We included data for 907 participants (age range 4–58 years from 21 studies, altogether including 28 substrata based on asthma type or severity. Only three of 21 included studies had high quality, whereas 93% of substudies reported lung function improvement with an overall pooled standardised mean difference (SMD of 0.53 (95% CI 0.43–0.62. The measured effect of HACT was greater in adults (SMD 0.75, 95% CI 0.63–0.88, n=14 than in children (SMD 0.24, 95% CI 0.09–0.38, n=14. Studies at altitude >2000 m above sea level yielded the same effect as those at lower altitude. Based on a cut-point of a 0.50 change in SMD to define a meaningful clinical difference, HACT appears to have efficacy as an intervention. This extent of benefit appears to be limited to adults with asthma.

  14. Is dietary nitrate supplementation necessary to ensure proper endothelial function at altitude?

    OpenAIRE

    Bakker, Emily

    2014-01-01

    Introduction: At altitude the body is exposed to systemic hypobaric hypoxia and adapts in order to optimize oxygen delivery to the tissue. Maintaining peripheral vascular function is essential in this process, tightly regulated through complex pathways involving local endothelium derived factors. Nitric oxide (NO) is the most important player in regulation of endothelial tone via endothelium dependent vasodilation. Dietary nitrate (NO3-) supplementation has been shown to increase NO bioavaila...

  15. Aerosol Characteristics at a High Altitude Location in Central Himalayas: Optical Properties and Radiative Forcing

    OpenAIRE

    Pant, P.; Hegde, P; Dumka, U. C.; Sagar, Ram; S. K. Satheesh; Moorthy, K. Krishna

    2006-01-01

    Collocated measurements of the mass concentrations of aerosol black carbon (BC) and composite aerosols near the surface were carried out along with spectral aerosol optical depths (AODs) from a high altitude station, Manora Peak in Central Himalayas, during a comprehensive aerosol field campaign in December 2004. Despite being a pristine location in the Shivalik Ranges of Central Himalayas, and having a monthly mean AOD (at 500 nm) of 0.059 $\\pm$ 0.033 (typical to this site), total suspended ...

  16. High-altitude Pulmonary Hypertension: an Update on Disease Pathogenesis and Management

    Science.gov (United States)

    Mirrakhimov, Aibek E.; Strohl, Kingman P.

    2016-01-01

    High-altitude pulmonary hypertension (HAPH) affects individuals residing at altitudes of 2,500 meters and higher. Numerous pathogenic variables play a role in disease inception and progression and include low oxygen concentration in inspired air, vasculopathy, and metabolic abnormalities. Since HAPH affects only some people living at high altitude genetic factors play a significant role in its pathogenesis. The clinical presentation of HAPH is nonspecific and includes fatigue, shortness of breath, cognitive deficits, cough, and in advanced cases hepatosplenomegaly and overt right-sided heart failure. A thorough history is important and should include a search for additional risk factors for lung disease and pulmonary hypertension (PH) such as smoking, indoor air pollution, left-sided cardiac disease and sleep disordered breathing. Twelve-lead electrocardiogram, chest X-ray and echocardiography can be used as screening tools. A definitive diagnosis should be made with right-sided heart catheterization using a modified mean pulmonary artery pressure of at least 30 mm Hg, differing from the 25 mm Hg used for other types of PH. Treatment of HAPH includes descent to a lower altitude whenever possible, oxygen therapy and the use of medications such as endothelin receptor antagonists, phosphodiesterase 5 blockers, fasudil and acetazolamide. Some recent evidence suggests that iron supplementation may also be beneficial. However, it is important to note that the scientific literature lacks long-term randomized controlled data on the pharmacologic treatment of HAPH. Thus, an individualized approach to treatment and informing the patients regarding the benefits and risks of the selected treatment regimen are essential. PMID:27014374

  17. Training Diaries during Altitude Training Camp in Two Olympic Champions: An Observational Case Study.

    Science.gov (United States)

    Pugliese, Lorenzo; Serpiello, Fabio R; Millet, Grégoire P; La Torre, Antonio

    2014-09-01

    Traditionally, Live High-Train High (LHTH) interventions were adopted when athletes trained and lived at altitude to try maximising the benefits offered by hypoxic exposure and improving sea level performance. Nevertheless, scientific research has proposed that the possible benefits of hypoxia would be offset by the inability to maintain high training intensity at altitude. However, elite athletes have been rarely recruited as an experimental sample, and training intensity has almost never been monitored during altitude research. This case study is an attempt to provide a practical example of successful LHTH interventions in two Olympic gold medal athletes. Training diaries were collected and total training volumes, volumes at different intensities, and sea level performance recorded before, during and after a 3-week LHTH camp. Both athletes successfully completed the LHTH camp (2090 m) maintaining similar absolute training intensity and training volume at high-intensity (> 91% of race pace) compared to sea level. After the LHTH intervention both athletes obtained enhancements in performance and they won an Olympic gold medal. In our opinion, LHTH interventions can be used as a simple, yet effective, method to maintain absolute, and improve relative training intensity in elite endurance athletes. Key PointsElite endurance athletes, with extensive altitude training experience, can maintain similar absolute intensity during LHTH compared to sea level.LHTH may be considered as an effective method to increase relative training intensity while maintaining the same running/walking pace, with possible beneficial effects on sea level performance.Training intensity could be the key factor for successful high-level LHTH camp. PMID:25177197

  18. Immunopathology features of chronic rhinosinusitis in high-altitude dwelling Tibetans

    OpenAIRE

    Luo, Ba; Feng, Liu; Jintao, Du; Yafeng, Liu; Shixi, Liu; Nan, Zhang; Bachert, Claus

    2013-01-01

    Chronic rhinosinusitis (CRS) presents distinct inflammatory and remodeling patterns in different populations and environments. Tibetan ethnic groups live at high altitudes and in cold weather conditions. We sought to examine whether Tibetans exhibit distinct CRS pathology or characteristics. Sinonasal polyps and mucosal tissue were obtained from 14 Tibetan patients with CRS and nasal polyps (CRSwNPs), 13 patients with CRS without nasal polyps (CRSsNPs), and 12 Tibetan controls. Tissue homogen...

  19. Agroforestry systems, nutrients in litter and microbial activity in soils cultivated with coffee at high altitude

    OpenAIRE

    Krystal de Alcantara Notaro; Erika Valente Medeiros; Gustavo Pereira Duda; Aline Oliveira Silva; Patrícia Maia de Moura

    2014-01-01

    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.) plantati...

  20. Intercomparison of cloud top altitudes as derived using GOME and ATSR-2 instruments onboard ERS-2

    OpenAIRE

    Rozanov, V. V.; A. A. Kokhanovsky; Loyola, Diego; Siddans, R.; Latter, B.; Stevens, A.; J. P. Burrows

    2006-01-01

    Cloud top heights as derived using measurements of two instruments (GOME and ATSR-2) onboard the ESA ERS-2 space platform are intercompared. It was found that cloud altitudes obtained using thermal IR measurements of ATSR-2 highly correlate with those obtained from top-of-atmosphere backscattered solar light measurements of GOME in O2 A-band using both the semi-analytical cloud retrieval algorithm SACURA and the neural network cloud retrieval algorithm ROCINN. The average cloud top heights as...

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

    OpenAIRE

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

    2012-01-01

    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 differenc...

  2. Low-Altitude Airbursts and the Impact Threat - Final LDRD Report.

    Energy Technology Data Exchange (ETDEWEB)

    Boslough, Mark B.; Crawford, David A.

    2007-12-01

    The purpose of this nine-week project was to advance the understanding of low-altitude airbursts by developing the means to model them at extremely high resolution in order to span the scales of entry physics as well as blast wave and plume formation. Small asteroid impacts on Earth are a recognized hazard, but the full nature of the threat is still not well understood. We used shock physics codes to discover emergent phenomena associated with low-altitude airbursts such as the Siberian Tunguska event of 1908 and the Egyptian glass-forming event 29 million years ago. The planetary defense community is beginning to recognize the significant threat from such airbursts. Low-altitude airbursts are the only class of impacts that have a significant probability of occurring within a planning time horizon. There is roughly a 10% chance of a megaton-scale low-altitude airburst event in the next decade.The first part of this LDRD final project report is a preprint of our proceedings paper associated with the plenary presentation at the Hypervelocity Impact Society 2007 Symposium in Williamsburg, Virginia (International Journal of Impact Engineering, in press). The paper summarizes discoveries associated with a series of 2D axially-symmetric CTH simulations. The second part of the report contains slides from an invited presentation at the American Geophysical Union Fall 2007 meeting in San Francisco. The presentation summarizes the results of a series of 3D oblique impact simulations of the 1908 Tunguska explosion. Because of the brevity of this late-start project, the 3D results have not yet been written up for a peer-reviewed publication. We anticipate the opportunity to eventually run simulations that include the actual topography at Tunguska, at which time these results will be published.3

  3. Altitude Exposure at 1800 m Increases Haemoglobin Mass in Distance Runners

    Directory of Open Access Journals (Sweden)

    Laura A. Garvican-Lewis, Iona Halliday, Chris R. Abbiss, Philo U. Saunders, Christopher J. Gore

    2015-06-01

    Full Text Available The influence of low natural altitudes (< 2000 m on erythropoietic adaptation is currently unclear, with current recommendations indicating that such low altitudes may be insufficient to stimulate significant increases in haemoglobin mass (Hbmass. As such, the purpose of this study was to determine the influence of 3 weeks of live high, train high exposure (LHTH at low natural altitude (i.e. 1800 m on Hbmass, red blood cell count and iron profile. A total of 16 elite or well-trained runners were assigned into either a LHTH (n = 8 or CONTROL (n = 8 group. Venous blood samples were drawn prior to, at 2 weeks and at 3 weeks following exposure. Hbmass was measured in duplicate prior to exposure and at 2 weeks and at 3 weeks following exposure via carbon monoxide rebreathing. The percentage change in Hbmass from baseline was significantly greater in LHTH, when compared with the CONTROL group at 2 (3.1% vs 0.4%; p = 0.01; and 3 weeks (3.0% vs -1.1%; p < 0.02, respectively following exposure. Haematocrit was greater in LHTH than CONTROL at 2 (p = 0.01 and 3 weeks (p = 0.04 following exposure. No significant interaction effect was observed for haemoglobin concentration (p = 0.06, serum ferritin (p = 0.43, transferrin (p = 0.52 or reticulocyte percentage (p = 0.16. The results of this study indicate that three week of natural classic (i.e. LHTH low altitude exposure (1800 m results in a significant increase in Hbmass of elite distance runners, which is likely due to the continuous exposure to hypoxia.

  4. Toward High Altitude Airship Ground-Based Boresight Calibration of Hyperspectral Pushbroom Imaging Sensors

    OpenAIRE

    Aiwu Zhang; Shaoxing Hu; Xiangang Meng; Lingbo Yang; Hanlun Li

    2015-01-01

    The complexity of the single linear hyperspectral pushbroom imaging based on a high altitude airship (HAA) without a three-axis stabilized platform is much more than that based on the spaceborne and airborne. Due to the effects of air pressure, temperature and airflow, the large pitch and roll angles tend to appear frequently that create pushbroom images highly characterized with severe geometric distortions. Thus, the in-flight calibration procedure is not appropriate to apply to the single ...

  5. Surnames, geographic altitude, and digital dermatoglyphics in a male population from the province of Jujuy (Argentina).

    Science.gov (United States)

    Dipierri, José E; Gutiérrez-Redomero, Esperanza; Alonso-Rodríguez, Concepción; Alfaro, Emma; Demarchi, Dario; Rivaldería, Noemí

    2014-06-01

    The possible association between finger dermatoglyphic patterns and altitude and surname distribution was analyzed in a sample of adult males from the province of Jujuy, Argentina. We also investigated the biological affinity of this population with other South American natives and admixed populations. Fingerprints were obtained from 996 healthy men, aged 18-20 years, from the highlands (HL: 2500m, Puna and Quebrada) and lowlands (LL: Valle and Selvas). Surnames were classified into native/autochthonous (A) or foreign (F), resulting in three surname classes: FF, when both paternal and maternal surnames were of foreign origin; FA, when one surname was foreign and the other was native; and AA, when both surnames were native. Frequencies of finger dermatoglyphic patterns - arches (A), radial loops (RL), ulnar loops (UL), and whorls (W) - were determined for each digit in relation to geographic location, altitude, and surname origin, resulting in the following categories: HL-FF, HL-FA, HL-AA, LL-FF, LL-FA, and LL-AA. The statistical analyses showed that UL and RL were more common in individuals of HL origin, whereas W and A were more frequent in the LL males (pdermatoglyphic patterns and surname origin when geographic altitude was considered. In the HL group, UL was associated with AA and FA; in the LL group, the presence of A was associated with FF and FA. The distribution of dermatoglyphic patterns shows that the population of Jujuy belongs to the Andean gene pool and that it has undergone differential levels of admixture related to altitude.

  6. On the prospects of ultra-high energy cosmic rays detection by high altitude antennas

    CERN Document Server

    Motloch, P; Privitera, P

    2013-01-01

    Radio emission from Ultra-High Energy Cosmic Rays (UHECR) showers detected after specular reflection off the Antarctic ice surface has been recently demonstrated by the ANITA balloon-borne experiment. An antenna observing a large area of ice or water from a mountaintop, a balloon or a satellite may be competitive with more conventional techniques. We present an estimate of the exposure of a high altitude antenna, which provides insight on the prospects of this technique for UHECR detection.

  7. 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.

  8. Metabolic adaptation of skeletal muscle to high altitude hypoxia: how new technologies could resolve the controversies

    OpenAIRE

    Murray, Andrew J.

    2009-01-01

    In most tissues of the body, cellular ATP production predominantly occurs via mitochondrial oxidative phosphorylation of reduced intermediates, which are in turn derived from substrates such as glucose and fatty acids. In order to maintain ATP homeostasis, and therefore cellular function, the mitochondria require a constant supply of fuels and oxygen. In many disease states, or in healthy individuals at altitude, tissue oxygen levels fall and the cell must meet this hypoxic challenge to maint...

  9. 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.

  10. Comparison between measured electron density at 600 km of altitude and IRI predictions

    Science.gov (United States)

    Ezquer, R. G.; Cabrera, M. A.; Mosert, M.; Araoz, L.

    The electron density at 600 Km of altitude (N 600) predicted by IRI are compared with the measurements for a given particular time and place (not average) obtained with the Japanese Hinotori satellite. The results show disagreements among predictions and measurements when the model uses the CCIR and URSI options to obtain the peak characteristics. Good predictions are obtained for same cases using ground ionosonde data as input parameters in the model.

  11. Mercury's Crustal Magnetic Field from Low-Altitude Measurements by MESSENGER.

    Science.gov (United States)

    Johnson, C. L.; Phillips, R. J.; Purucker, M. E.; Anderson, B. J.; Byrne, P. K.; Denevi, B. W.; Fan, K. A.; Feinberg, J. M.; Hauck, S. A., II; Head, J. W., III; Korth, H.; James, P. B.; Mazarico, E.; Neumann, G. A.; Philpott, L. C.; Siegler, M. A.; Strauss, B. E.; Tsyganenko, N. A.; Solomon, S. C.

    2015-12-01

    Magnetized rocks can record the history of a planet's magnetic field, a key constraint for understanding interior evolution. From orbital vector magnetic field measurements of Mercury taken by the MESSENGER spacecraft at altitudes below 150 km, we have detected fields indicative of crustal magnetization. Fields from non-crustal sources, which dominate the observations even at low altitudes, were estimated and subtracted from the observations using both magnetospheric models and signal filtering. The resulting high-pass filtered fields have amplitudes of a few to 20 nT. The first low-altitude signals were detected over the Suisei Planitia region and were confirmed by upward continuation to be of crustal origin. At least some contribution from thermoremanent magnetization is required to account for these signals, and we infer a lower bound on the average age of magnetization of 3.7-3.9 Ga on the basis of correlation of crustal magnetic fields with volcanic units of that age range. Ancient field strengths that range from those similar to Mercury's present dipole field to Earth-like values are consistent with the magnetic field observations and with the low iron content of Mercury's crust derived from MESSENGER elemental composition data. Here, we extend these initial results with observations obtained at spacecraft altitudes below 60 km at all body-fixed longitudes from ~40°N to ~75°N. The strongest crustal fields occur in the region 120°E to 210°E, and weaker signals characterize the northern volcanic plains. We test the hypothesis that the longest-wavelength crustal field signals in this region reflect magnetization contrasts between the Caloris basin and the surrounding intercrater plains and circum-Caloris plains. We report the spatial distribution of observed crustal fields, together with magnetization models derived from them and the implications of these models, particularly for the depth distribution of sources compatible with the observations.

  12. Quantitative wildlife habitat evaluation using high-altitude color infrared aerial photographs

    Science.gov (United States)

    Pettinger, Lawrence R.; Farmer, Adrian; Schamberger, Mel

    1978-01-01

    The habitat value for elk and sage grouse of two proposed phosphate strip mine sites was determined using habitat parameter measurements from high-altitude color infrared aerial photographs. Habitat suitability was assessed using the Habitat Evaluation Procedures being developed by the U.S. Fish and Wildlife Service. Similar results were obtained from two approaches--a remote-sensing-only approach and a mix of measurements from photo interpretation and conventional field surveys.

  13. Detection of Laurel Wilt Disease in Avocado Using Low Altitude Aerial Imaging

    OpenAIRE

    Ana I de Castro; Ehsani, Reza; Ploetz, Randy C.; Jonathan H Crane; Buchanon, Sherrie

    2015-01-01

    Laurel wilt is a lethal disease of plants in the Lauraceae plant family, including avocado (Persea americana). This devastating disease has spread rapidly along the southeastern seaboard of the United States and has begun to affect commercial avocado production in Florida. The main objective of this study was to evaluate the potential to discriminate laurel wilt-affected avocado trees using aerial images taken with a modified camera during helicopter surveys at low-altitude in the commercial ...

  14. Mechanisms underlying reductions in stroke volume at rest and during exercise at high altitude.

    Science.gov (United States)

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

    2016-08-01

    High-altitude exposure challenges the cardiovascular system to maintain oxygen delivery to the mitochondria under conditions of hypoxic stress. Following acclimatisation (3-5 days), stroke volume (SV) falls to below sea-level values but heart rate remains elevated, such that cardiac output is maintained compared to sea level. The decrease in SV has been a topic of research for over 40 years, but the underlying mechanisms are incompletely understood. Impaired systolic contractile function secondary to reduced coronary arterial oxygen tension has been investigated as a potential cause for the decrease in SV. However, despite in vitro evidence of impaired cardiac contractile force in severe hypoxia, the majority of studies to date have reported enhanced in vivo ventricular systolic function at rest and during exercise in humans up to and above 5000 m. However, the elevated function observed at rest has recently been suggested to reduce the functional reserve available during exercise. While in vivo systolic function appears enhanced at high altitude, a decrease in left ventricular end-diastolic volume (EDV) and altered filling patterns of both ventricles has been observed. The reduction in ventricular filling will undoubtedly affect SV, and four potential mechanisms have been proposed to explain the reduction in left ventricular filling. In this article, both historical and recent reports of systolic function at high altitude will be reviewed, and evidence supporting and refuting each of the four mechanisms underpinning reduced left ventricular filling will be discussed. PMID:26325452

  15. Hemoglobin and hematocrit values of Saudi newborns in the high altitude of Abha, Saudi Arabia

    International Nuclear Information System (INIS)

    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)

  16. Hydration and tissue solid content of the lean body on prolonged exposure to altitude

    Science.gov (United States)

    Bharadwaj, H.; Singh, M. V.; Rawal, S. B.; Zachariah, T.; Kishnani, S.; Pramanik, S. N.; Gupta, A.; Rai, R. M.

    1989-03-01

    Using densitometric, hydrometric and anthropometric techniques, body fat, tissue solids, water and mineral content were quantitatively measured on two groups each of 26 young and healthy Indian soldiers of mixed ethnic composition. The experimental group was exposed to 3500 m altitude for 2 years and the experiments were carried out after 48 h and 3 weeks rehabilitation in Delhi (300 m). The control group was never exposed to high altidues. Inspite of the experimental group being fed with superior rations at high altitude, this group showed significantly hyperhydrated lean body with reduced tissue solids in comparison to the control group which was fed with identical rations in Delhi. The calculated mean density of the fat free body had declined to 0.092×103 kg/m3. The 3 week stay at low altitude had little influence on body composition. Hyperhydration, with reduced tissue solids, would cause reduction in the density of fat free body, and would thus interfere with the estimates of total body fat based on densitometric procedures alone. In the hyperhydrated state, Siri's formula overestimated fat by 22.8% of the true value.

  17. 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

  18. Association between Serum Interleukin-17A Level and High-Altitude Deacclimatization Syndrome

    Directory of Open Access Journals (Sweden)

    Binfeng He

    2016-01-01

    Full Text Available High-altitude deacclimatization syndrome (HADAS is emerging as a severe public health issue that threatens the quality of life of individuals who return to lower altitude from high altitude. In this study, we measured serum levels of SOD, MDA, IL-17A, IL-10, TNF-α, and HADAS score in HADAS subjects at baseline and 50th and 100th days and to evaluate the relationship between interleukins, including IL-17A, and HADAS. Our data showed that and the serum IL-17A levels and HADAS score decreased over time in the HADAS group, and serum IL-17A levels were significantly higher in the HADAS group at baseline and 50th day compared with controls (p<0.05. Furthermore, baseline serum levels of MDA and TNF-α were significantly higher, while SOD and IL-10 levels were lower in HADAS subjects compared with controls (p<0.05. It is interesting that serum levels of IL-17A were clearly interrelated with HADAS incidence and severity (p<0.05. ROC curve analysis showed that combined serum IL-17A and IL-10 levels were a better predictor of HADAS incidence than serum levels of IL-17A or IL-10 alone. These data suggest that serum levels of IL-17A are a novel predictive index of HADAS.

  19. Development and demonstration flight of a fuel cell system for high-altitude balloons

    Energy Technology Data Exchange (ETDEWEB)

    Uno, Masatoshi; Shimada, Takanobu; Sone, Yoshitsugu; Saito, Yoshitaka [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510 (Japan); Ariyama, Yusuke; Fukuzawa, Naoya; Noguchi, Daisuke [Hosei University, Koganei, Tokyo 184-8584 (Japan); Ogawa, Keita [Advanced Engineering Services, Tsukuba, Ibaraki 305-0032 (Japan); Naito, Hitoshi [Aerospace Research and Development Directorate, Japan Aerospace Exploration Agency, Tsukuba, Ibaraki 305-8505 (Japan)

    2009-09-05

    Proton exchange membrane fuel cell offers higher energy density than the existing battery technologies for high-energy applications, and it is a promising power source for various industries including aerospace vehicles. We have been developing and testing a non-external humidified fuel cell system for high-altitude balloons, which require simple, light, and easy-to-operate power systems. This system consists of three major subsystems - a fuel cell stack, a reactant supply subsystem, and an electrical control subsystem. Ground performance testing in a vacuum chamber simulating the high-altitude vacuum condition was performed before the flight. Then, a demonstration flight of the fuel cell system was launched using a large balloon for verifying its performance under practical high-altitude conditions. Cell voltage variations synchronized with oxygen pressure spikes were observed that were probably caused by condensed product water plugging the flow passages of the back pressure regulator. Flight results indicated that the fuel cell system operated better when water was expelled as vapor, rather than in the liquid form. In addition, a back pressure regulator should be installed to avoid the accumulation of water droplets for realizing a stable performance. (author)

  20. Altitude Effects on Thermal Ice Protection System Performance; a Study of an Alternative Approach

    Science.gov (United States)

    Addy, Harold E., Jr.; Orchard, David; Wright, William B.; Oleskiw, Myron

    2016-01-01

    Research has been conducted to better understand the phenomena involved during operation of an aircraft's thermal ice protection system under running wet icing conditions. In such situations, supercooled water striking a thermally ice-protected surface does not fully evaporate but runs aft to a location where it freezes. The effects of altitude, in terms of air pressure and density, on the processes involved were of particular interest. Initial study results showed that the altitude effects on heat energy transfer were accurately modeled using existing methods, but water mass transport was not. Based upon those results, a new method to account for altitude effects on thermal ice protection system operation was proposed. The method employs a two-step process where heat energy and mass transport are sequentially matched, linked by matched surface temperatures. While not providing exact matching of heat and mass transport to reference conditions, the method produces a better simulation than other methods. Moreover, it does not rely on the application of empirical correction factors, but instead relies on the straightforward application of the primary physics involved. This report describes the method, shows results of testing the method, and discusses its limitations.