WorldWideScience

Sample records for high altitude links

  1. 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

  2. High Altitude Pilgrimage Medicine

    Science.gov (United States)

    2014-01-01

    Abstract Religious pilgrims have been going to high altitude pilgrimages long before trekkers and climbers sojourned in high altitude regions, but the medical literature about high altitude pilgrimage is sparse. Gosainkunda Lake (4300 m) near Kathmandu, Nepal, and Shri Amarnath Yatra (3800 m) in Sri Nagar, Kashmir, India, are the two sites in the Himalayas from where the majority of published reports of high altitude pilgrimage have originated. Almost all travels to high altitude pilgrimages are characterized by very rapid ascents by large congregations, leading to high rates of acute mountain sickness (AMS). In addition, epidemiological studies of pilgrims from Gosainkunda Lake show that some of the important risk factors for AMS in pilgrims are female sex and older age group. Studies based on the Shri Amarnath Yatra pilgrims show that coronary artery disease, complications of diabetes, and peptic ulcer disease are some of the common, important reasons for admission to hospital during the trip. In this review, the studies that have reported these and other relevant findings will be discussed and appropriate suggestions made to improve pilgrims' safety at high altitude. PMID:25330393

  3. 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

  4. High altitude organic gold

    DEFF Research Database (Denmark)

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

    2018-01-01

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

  5. High Altitude Cerebral Edema

    Science.gov (United States)

    1986-03-01

    reflected a cerebral form of high altitude illness. In 1964, Fitch described a similar form of mountain sickness with neurolkgical manifestations in the...71% in thaL of Hackett et al; this sex distribution undoubtedly reflects the larger numbers of males presently involved in trekking and 44...HACE with loss of consciousness, absence of pupillary reactions, flaccidity of all extremities and the presence of bilateral Babinski responses. The

  6. Coexistence Performance of High-Altitude Platform and Terrestrial Systems Using Gigabit Communication Links to Serve Specialist Users

    Directory of Open Access Journals (Sweden)

    D. Grace

    2008-10-01

    Full Text Available This paper presents three feasible methods to serve specialist users within a service area of up to 150 km diameter by using spot-beam gigabit wireless communication links from high-altitude platforms (HAPs. A single HAP serving multiple spot beams coexists with terrestrial systems, all sharing a common frequency band. The schemes provided in the paper are used to adjust the pointing direction of aperture antennas operating in the mm-wave bands, such that the peak carrier to interference plus noise ratio (CINR is delivered directly toward the location of the specialist users; the schemes include the small step size scheme, half distance scheme, and beam switch scheme. The pointing process is controlled iteratively using the mean distance between the peak CINR locations and user positions. The paper shows that both the small step size and half distance schemes significantly enhance the CINR at the user, but performance is further improved if beams with adverse performance below a specific threshold are switched off, or are assigned another channel.

  7. Coexistence Performance of High-Altitude Platform and Terrestrial Systems Using Gigabit Communication Links to Serve Specialist Users

    Directory of Open Access Journals (Sweden)

    Peng Z

    2008-01-01

    Full Text Available Abstract This paper presents three feasible methods to serve specialist users within a service area of up to 150 km diameter by using spot-beam gigabit wireless communication links from high-altitude platforms (HAPs. A single HAP serving multiple spot beams coexists with terrestrial systems, all sharing a common frequency band. The schemes provided in the paper are used to adjust the pointing direction of aperture antennas operating in the mm-wave bands, such that the peak carrier to interference plus noise ratio (CINR is delivered directly toward the location of the specialist users; the schemes include the small step size scheme, half distance scheme, and beam switch scheme. The pointing process is controlled iteratively using the mean distance between the peak CINR locations and user positions. The paper shows that both the small step size and half distance schemes significantly enhance the CINR at the user, but performance is further improved if beams with adverse performance below a specific threshold are switched off, or are assigned another channel.

  8. High Altitude Towed Glider

    Science.gov (United States)

    Colozza, Anthony J.

    1996-01-01

    The concept of using an unmanned towed glider for high altitude scientific research had been previously proposed. This paper examines the feasibility of this concept by determining what impact the various characteristics of the tow line, glider and tow aircraft have on tow line drag. A description of the analysis and computer code used to generate the results is given. The parameters examined were glider altitude, tow aircraft glider separation distance, velocity, tow line drag coefficient and tow line material properties. The results from the analysis show that the tow line drag increases significantly with tow aircraft/glider separation. The drag increased from 940 N (211 lb) with a tow aircraft/glider separation of 3 km to 11,970 N (2691 lb) with a tow aircraft/glider separation of 10 km. The results also show that by varying some of the initial assumptions significant reductions in tow line drag and weight can be obtained. The variables which had the greatest effect on reducing the tow line drag were the decrease in tow aircraft/glider separation distance, the increase in tow line strength and the decrease in glider Mach number.

  9. Linking carbon supply to root cell-wall chemistry and mechanics at high altitudes in Abies georgei.

    Science.gov (United States)

    Genet, Marie; Li, Mingcai; Luo, Tianxiang; Fourcaud, Thierry; Clément-Vidal, Anne; Stokes, Alexia

    2011-02-01

    The mobile carbon supply to different compartments of a tree is affected by climate, but its impact on cell-wall chemistry and mechanics remains unknown. To understand better the variability in root growth and biomechanics in mountain forests subjected to substrate mass movement, we investigated root chemical and mechanical properties of mature Abies georgei var. smithii (Smith fir) growing at different elevations on the Tibet-Qinghai Plateau. Thin and fine roots (0·1-4·0 mm in diameter) were sampled at three different elevations (3480, 3900 and 4330 m, the last corresponding to the treeline). Tensile resistance of roots of different diameter classes was measured along with holocellulose and non-structural carbon (NSC) content. The mean force necessary to break roots in tension decreased significantly with increasing altitude and was attributed to a decrease in holocellulose content. Holocellulose was significantly lower in roots at the treeline (29·5 ± 1·3 %) compared with those at 3480 m (39·1 ± 1·0 %). Roots also differed significantly in NSC, with 35·6 ± 4·1 mg g(-1) dry mass of mean total soluble sugars in roots at 3480 m and 18·8 ± 2·1 mg g(-1) dry mass in roots at the treeline. Root mechanical resistance, holocellulose and NSC content all decreased with increasing altitude. Holocellulose is made up principally of cellulose, the biosynthesis of which depends largely on NSC supply. Plants synthesize cellulose when conditions are optimal and NSC is not limiting. Thus, cellulose synthesis in the thin and fine roots measured in our study is probably not a priority in mature trees growing at very high altitudes, where climatic factors will be limiting for growth. Root NSC stocks at the treeline may be depleted through over-demand for carbon supply due to increased fine root production or winter root growth.

  10. Acute high-altitude sickness

    Directory of Open Access Journals (Sweden)

    Andrew M. Luks

    2017-02-01

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

  11. High-Altitude Cirrus Clouds and Climate

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 9; Issue 3. High-Altitude Cirrus Clouds and Climate. S Veerabuthiran. General Article Volume 9 Issue 3 March 2004 pp 23-32. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/009/03/0023-0032. Keywords.

  12. 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.

  13. Measuring high-altitude adaptation.

    Science.gov (United States)

    Moore, Lorna G

    2017-11-01

    High altitudes (>8,000 ft or 2,500 m) provide an experiment of nature for measuring adaptation and the physiological processes involved. Studies conducted over the past ~25 years in Andeans, Tibetans, and, less often, Ethiopians show varied but distinct O2 transport traits from those of acclimatized newcomers, providing indirect evidence for genetic adaptation to high altitude. Short-term (acclimatization, developmental) and long-term (genetic) responses to high altitude exhibit a temporal gradient such that, although all influence O2 content, the latter also improve O2 delivery and metabolism. Much has been learned concerning the underlying physiological processes, but additional studies are needed on the regulation of blood flow and O2 utilization. Direct evidence of genetic adaptation comes from single-nucleotide polymorphism (SNP)-based genome scans and whole genome sequencing studies that have identified gene regions acted upon by natural selection. Efforts have begun to understand the connections between the two with Andean studies on the genetic factors raising uterine blood flow, fetal growth, and susceptibility to Chronic Mountain Sickness and Tibetan studies on genes serving to lower hemoglobin and pulmonary arterial pressure. Critical for future studies will be the selection of phenotypes with demonstrable effects on reproductive success, the calculation of actual fitness costs, and greater inclusion of women among the subjects being studied. The well-characterized nature of the O2 transport system, the presence of multiple long-resident populations, and relevance for understanding hypoxic disorders in all persons underscore the importance of understanding how evolutionary adaptation to high altitude has occurred.NEW & NOTEWORTHY Variation in O2 transport characteristics among Andean, Tibetan, and, when available, Ethiopian high-altitude residents supports the existence of genetic adaptations that improve the distribution of blood flow to vital organs

  14. High Altitude Cooking and Food Safety

    Science.gov (United States)

    ... Standard Forms FSIS United States Department of Agriculture Food Safety and Inspection Service About FSIS District Offices Careers ... 286) Actions ${title} Loading... High Altitude Cooking and Food Safety What is considered a high altitude? How is ...

  15. 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 proven...

  16. Travelling safely to places at high altitude - Understanding and preventing altitude illness.

    Science.gov (United States)

    Parise, Ivan

    2017-06-01

    Greater numbers of people are travelling to places at high altitude each year. Altitude illness is common in places at high altitude and may be life-threatening. General practitioners (GPs) are best placed to provide evidence-based advice to keep travellers well informed of the possible risks they may encounter in places at high altitude. The aim of this article is to review knowledge on altitude illness in order to help GPs assist patients to travel safely to places at high altitude. Acclimatisation to high altitude is a complex process and when inadequate leads to the pathological changes of altitude illness, including high-altitude headache, cerebral oedema, pulmonary oedema and acute mountain sickness. Higher ascent, faster rate of ascent and a previous history of altitude illness increase the risk of altitude illness. Acetazolamide and other medications used to prevent altitude illness are discussed in detail, including the finding that inhaled budesonide may prevent altitude illness.

  17. High-Altitude Electromagnetic Pulse (HEMP) Testing

    Science.gov (United States)

    2015-07-09

    Final 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE Test Operations Procedure (TOP) 01-2-620A High-Altitude Electromagnetic Pulse ( HEMP ...planning and execution of testing Army/DOD equipment to determine the effects of Horizontal Component High Altitude Electromagnetic Pulse ( HEMP ...5 2.3 HEMP Pre/Post Test Illuminations ..................................................... 7 3. REQUIRED TEST

  18. High-altitude adaptations in vertebrate hemoglobins

    DEFF Research Database (Denmark)

    Weber, Roy E.

    2007-01-01

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

  19. High-Altitude Hydration System

    Science.gov (United States)

    Parazynski, Scott E.; Orndoff, Evelyne; Bue, Grant C.; Schaefbauer, Mark E.; Urban, Kase

    2010-01-01

    Three methods are being developed for keeping water from freezing during high-altitude climbs so that mountaineers can remain hydrated. Three strategies have been developed. At the time of this reporting two needed to be tested in the field and one was conceptual. The first method is Passive Thermal Control Using Aerogels. This involves mounting the fluid reservoir of the climber s canteen to an inner layer of clothing for better heat retention. For the field test, bottles were mounted to the inner fleece layer of clothing, and then aerogel insulation was placed on the outside of the bottle, and circumferentially around the drink straw. When climbers need to drink, they can pull up the insulated straw from underneath the down suit, take a sip, and then put it back into the relative warmth of the suit. For the field test, a data logger assessed the temperatures of the water reservoir, as well as near the tip of the drink straw. The second method is Passive Thermal Control with Copper-Shielded Drink Straw and Aerogels, also mounted to inner layers of clothing for better heat retention. Braided wire emanates from the inside of the fleece jacket layer, and continues up and around the drink straw in order to use body heat to keep the system-critical drink straw warm enough to keep water in the liquid state. For the field test, a data logger will be used to compare this with the above concept. The third, and still conceptual, method is Active Thermal Control with Microcontroller. If the above methods do not work, microcontrollers and tape heaters have been identified that could keep the drink straw warm even under extremely cold conditions. Power requirements are not yet determined because the thermal environment inside the down suit relative to the external environment has not been established. A data logger will be used to track both the external and internal temperatures of the suit on a summit day.

  20. Pupillary light reaction during high altitude exposure.

    Directory of Open Access Journals (Sweden)

    Maximilian Schultheiss

    Full Text Available PURPOSE: This study aimed to quantify the pupillary light reaction during high altitude exposure using the state of the art Compact Integrated Pupillograph (CIP and to investigate a potential correlation of altered pupil reaction with severity of acute mountain sickness (AMS. This work is related to the Tübingen High Altitude Ophthalmology (THAO study. METHODS: Parameters of pupil dynamics (initial diameter, amplitude, relative amplitude, latency, constriction velocity were quantified in 14 healthy volunteers at baseline (341 m and high altitude (4559 m over several days using the CIP. Scores of AMS, peripheral oxygen saturation and heart rate were assessed for respective correlations with pupil dynamics. For statistical analysis JMP was used and data are shown in terms of intra-individual normalized values (value during exposure/value at baseline and the 95% confidence interval for each time point. RESULTS: During high altitude exposure the initial diameter size was significantly reduced (p<0.05. In contrast, the amplitude, the relative amplitude and the contraction velocity of the light reaction were significantly increased (p<0.05 on all days measured at high altitude. The latency did not show any significant differences at high altitude compared to baseline recordings. Changes in pupil parameters did not correlate with scores of AMS. CONCLUSIONS: Key parameters of the pupillary light reaction are significantly altered at high altitude. We hypothesize that high altitude hypoxia itself as well as known side effects of high altitude exposure such as fatigue or exhaustion after ascent may account for an altered pupillogram. Interestingly, none of these changes are related to AMS.

  1. Delayed appearance of high altitude retinal hemorrhages.

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    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.

  2. 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...

  3. Early history of high-altitude physiology.

    Science.gov (United States)

    West, John B

    2016-02-01

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

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

    Science.gov (United States)

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

    2010-01-01

    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 and/or genetic adaptation in response to the high-altitude environment. We approach the question of human adaptation to high altitude from a somewhat unique vantage point; namely, by examining physiological characteristics – pregnancy and pregnancy outcome -- that are most closely associated with reproductive fitness. Here we review the potent example of high-altitude native population’s resistance to hypoxia-associated reductions in birth weight, which is often associated with higher infant morbidity and mortality at high altitude. With the exception of two recent publications, these comparative birth weight studies have utilized surnames, self-identification and/or linguistic characteristics to assess ancestry, and none have linked ‘advantageous’ phenotypes to specific genetic variations. Recent advancements in genetic and statistical tools have enabled us to assess individual ancestry with higher resolution, identify the genetic basis of complex phenotypes and to infer the effect of natural selection on specific gene regions. Using these technologies our studies are now directed to determine the genetic variations that underlie the mechanisms by which high-altitude ancestry protects fetal growth and, in turn, to further our understanding of evolutionary processes involved in human adaptation to high altitude. PMID:19367578

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

    Science.gov (United States)

    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. Frisancho helped to 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, and/or genetic adaptation in response to the high-altitude environment. We approach the question of human adaptation to high altitude from a somewhat unique vantage point; namely, by examining physiological characteristics-pregnancy and pregnancy outcome-which are closely associated with reproductive fitness. Here we review the potent example of high-altitude native population's resistance to hypoxia-associated reductions in birth weight, which is often associated with higher infant morbidity and mortality at high altitude. With the exception of two recent publications, these comparative birth weight studies have utilized surnames, self-identification, and/or linguistic characteristics to assess ancestry, and none have linked 'advantageous' phenotypes to specific genetic variations. Recent advancements in genetic and statistical tools have enabled us to assess individual ancestry with higher resolution, identify the genetic basis of complex phenotypes and to infer the effect of natural selection on specific gene regions. Using these technologies our studies are now directed to determine the genetic variations that underlie the mechanisms by which high-altitude ancestry protects fetal growth and, in turn, to further our understanding of evolutionary processes involved in human adaptation to high altitude.

  6. Medical and Performance Problems of Acute High Altitude-Exposure,

    Science.gov (United States)

    1981-07-11

    200 0 o. .. _k . - -- SEA LEVEL ACUTE HIGH CHRONIC HIGH SEA LEVEL ACUTE HIH CHRONIC HIGH ALTITUDE ALTITUDE ALTITUDE ALTITUDE Figre 7. Mecan concenttion...AD-AIll 062 ARMY RESEARCH INST OF ENVIRONMENTAL MEDICINE NATICK MA FIG 6/19 MEDICAL AND PERFORMANCE PROBLEMS OF ACUTE HIGH ALTITUDE-EXPOSUR--ETC(U...TYPE OF REPORT & PERID COVERED of Acute High Altitude-Exposure 6. PERFORMING ORG. REPORT NUMBER 7. AUTHOR(°60hn T. Maher . CONTRACT OR GRANT NUMBER(S

  7. Pulmonary Embolism Masquerading as High Altitude Pulmonary Edema at High Altitude.

    Science.gov (United States)

    Pandey, Prativa; Lohani, Benu; Murphy, Holly

    2016-12-01

    Pandey, Prativa, Benu Lohani, and Holly Murphy. Pulmonary embolism masquerading as high altitude pulmonary edema at high altitude. High Alt Med Biol. 17:353-358, 2016.-Pulmonary embolism (PE) at high altitude is a rare entity that can masquerade as or occur in conjunction with high altitude pulmonary edema (HAPE) and can complicate the diagnosis and management. When HAPE cases do not improve rapidly with descent, other diagnoses, including PE, ought to be considered. From 2013 to 2015, we identified eight cases of PE among 303 patients with initial diagnosis of HAPE. Upon further evaluation, five had deep vein thrombosis (DVT). One woman had a contraceptive ring and seven patients had no known thrombotic risks. PE can coexist with or mimic HAPE and should be considered in patients presenting with shortness of breath from high altitude regardless of thrombotic risk.

  8. Can High Altitude Influence Cytokines and Sleep?

    Science.gov (United States)

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

    2013-01-01

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

  9. 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.

  10. Pulmonary Adaptation to High Altitude.

    Science.gov (United States)

    1983-08-12

    T.I. Musch, and J.A. Dempsey. Central- peripheral chemoreceptor interaction in the awake CSF-perfused goat. J. Appl. Physiol. (accepted for...of obtaining limb and respiratory muscles. Assays are cur- rently being done for fiber type, oxidative capacity (citrase synthase activity ) and high...hypoxia. III. Mechanism of Periodic Breathing in Hypoxia Sleep--Humans A. We have now completed our study and analysis of the role of chemoreceptor stimuli

  11. Italian high altitude laboratories: past and present.

    Science.gov (United States)

    Cogo, A; Ponchia, A; Pecchio, O; Losano, G; Cerretelli, P

    2000-01-01

    Italy is a mountainous country with a total of 88 huts and bivouacs at altitudes higher than 3,000 m. Starting in the 19th century a great deal of research in high altitude pathophysiology has been carried out in Italy and many Italian physicians have been involved in mountain medicine. Most of the Italian research has been carried out at two locations: the scientific laboratories "Angelo Mosso" on Monte Rosa (Capanna Regina Margherita and Laboratorio Angelo Mosso), and the "Pyramid" in Nepal. The Capanna Regina Margherita, located on the top of Punta Gnifetti (Monte Rosa, 4,559 m), was inaugurated in 1893. With the support of Queen Margherita of Savoy, an Observatory for scientific studies was built beside this hut in 1894. In 1980 the hut was completely rebuilt by the Italian Alpine Club. The Istituto Angelo Mosso at Col d'Olen, at the base of Monte Rosa (at 2,900 m) was inaugurated in 1907. The high altitude laboratory named the "Pyramid" was built in 1990. Made of glass and aluminium, this pyramid-shaped structure is situated in Nepal at 5,050 m. The scientific laboratories "Angelo Mosso" on Monte Rosa (mainly the Capanna Regina Margherita) and the Pyramid form a nucleus for high altitude research: the former is especially devoted to research regarding acute mountain sickness and the response to subacute hypoxia, whereas the latter is a unique facility for research responses to chronic hypoxia, the effect of exposure to very high altitude, and the study of the resident population living in the Himalayas for at least 25,000 years.

  12. [Otorhinolaryngological aspects of high altitude medicine].

    Science.gov (United States)

    Mees, K; Olzowy, B

    2008-04-01

    The World Health Organisation estimates that about 40 million tourists every year climb to high (2,500-5,300 m) and extremely high altitudes (5,300-8,850 m). Thus altitude sickness and other health risks are increasing accordingly and so this fact requires clarification and advice for tourists in order to reduce the risks. That applies to the otolaryngologist, too. The non-traumatic health risks all result from the atmospheric conditions at high altitudes, in particular due to the lower atmospheric pressure. The partial pressure of oxygen (pO2), the temperature and the partial pressure of water vapour decrease continuously with increasing altitude and at the summit of the highest mountain on earth, Mt. Everest, the pO2 is reduced by two-thirds, from 212 to about 70 hPa. The temperature drops on average 6.5 degrees C per 1,000 m and at -20 degrees C 1 m3 of air contains at most just about 1 g of water vapour. The shortage of oxygen above 2500 m cannot be compensated for at once. Respiratory alcalosis, followed by hyperventilation, improves the alveolar loading of red blood cells (RBC) with oxygen, however, it also reduces the ventilatory drive from the central CO2-chemosensors as well from the peripheral O2-chemosensors located in the carotid bodies. Not until the alcalosis has been balanced by a renal secretion of bicarbonate, does the pO2-driven ventilatory stimulus normalize and the relative increase of RBC as a result of altitude diuresis improve and complete the acclimatisation. Up to an altitude of 4,000 m this adaptation takes several days to one week and up to 5,000 m up to 2 weeks. If acclimatisation has not taken place or has been insufficient, acute mountain sickness may develop. It is a harmless disorder, although it noticeably affects people physically and mentally and in some rare cases it might even develop into a life-threatening high-altitude edema in the brain or in the lung. Hematocrit values of up to 58 or even 60% at great altitudes are quite

  13. 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.

  14. HIGH ALTITUDES EFFECTS ON HEMATOLOGIC BLOOD PARAMETERS

    Directory of Open Access Journals (Sweden)

    Hasim Rushiti

    2015-05-01

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

  15. GRIP HIGH-ALTITUDE MMIC SOUNDING RADIOMETER (HAMSR) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The GRIP High-Altitude MMIC Sounding Radiometer (HAMSR) dataset was collectd by the High Altitude monolithic microwave integrated Circuit (MMIC) Sounding Radiometer...

  16. Trajectory Control For High Altitude Balloons

    Science.gov (United States)

    Aaron, K.; Nock, K.; Heun, M.; Wyszkowski, C.

    We will discuss the continuing development of the StratoSailTM Balloon Trajectory Control System presented at the 33rd COSPAR in 2000. A vertical wing suspended on a 15-km tether from a high altitude balloon uses the difference in wind velocity between the altitude of the balloon and the altitude of the wing to create an aerodynamic sideforce. This sideforce, transmitted to the balloon gondola via the tether, causes the balloon to move laterally. Although the balloon's resultant drift velocity is quite small (a few meters per second), the effect becomes significant over long periods of time (hours to days). Recently, a full-scale wing, rudder and boom assembly has been fabricated, a winch system testbed has been completed, and a lightweight tether with reduced susceptibility to ultraviolet damage has been developed. The development effort for this invention, with pending international patents, has been funded by the NASA/SBIR program in support of the Ultra Long Duration Balloon (ULDB) program.

  17. AltitudeOmics: The Basic Biology of Human Acclimatization to High Altitude

    Science.gov (United States)

    2013-01-01

    11-2-0040 TITLE: AltitudeOmics: The Basic Biology of Human Acclimatization to High Altitude PRINCIPAL INVESTIGATOR: Robert Roach...code) Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std. Z39.18 AltitudeOmics: The Basic Biology of Human Acclimatization to High...shipped from Bolivia to Denver and are currently undergoing analysis . 5 CONCLUSION: Humans retain acclimatization after 7 and 21 days of de

  18. Role of the altitude level on cerebral autoregulation in residents at high altitude

    NARCIS (Netherlands)

    Jansen, Gerard F. A.; Krins, Anne; Basnyat, Buddha; Odoom, Joseph A.; Ince, Can

    2007-01-01

    Cerebral autoregulation is impaired in Himalayan high-altitude residents who live above 4,200 m. This study was undertaken to determine the altitude at which this impairment of autoregulation occurs. A second aim of the study was to test the hypothesis that administration of oxygen can reverse this

  19. Growth among Tibetans at high and low altitudes in India.

    Science.gov (United States)

    Tripathy, Vikal; Gupta, Ranjan

    2007-01-01

    In India, Tibetans have been living at different altitudes for more than 40 years. This study describes physical growth in terms of height, weight, sitting height, skinfold thickness at triceps and upper arm circumference of Tibetans born and raised at three Tibetan refugee settlements (3,521; 970; and 800 m) from the view point of the hypothesis that growth is retarded at high altitude. Samples consist of individuals between the ages of 2 and 40 years. Tibetans at high altitude in India show a growth pattern similar to that previously observed among Tibetans in Tibet. Tibetans at high altitude are taller and heavier compared to Andean highlanders. The general trends show that Tibetan children and adults of both sexes at low altitude in India are advanced in terms of height, weight, skinfold thickness at triceps and upper arm circumference compared to Tibetans at high altitude. Trunk length (sitting height) is similar at the two altitudes but relative sitting height is greater at high altitude. Greater relative sitting height and lesser leg length at high altitude than at low altitudes is discussed in terms of effect of altitude, temperature, and nutritional status. Copyright 2007 Wiley-Liss, Inc.

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

    OpenAIRE

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

    2011-01-01

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

  1. GRIP HIGH-ALTITUDE MMIC SOUNDING RADIOMETER (HAMSR) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The High Altitude monolithic microwave integrated Circuit (MMIC) Sounding Radiometer (HAMSR) is a microwave atmospheric sounder developed by JPL under the NASA...

  2. The link between outgoing longwave radiation and the altitude at which a spaceborne lidar beam is fully attenuated

    Science.gov (United States)

    Vaillant de Guélis, Thibault; Chepfer, Hélène; Noel, Vincent; Guzman, Rodrigo; Dubuisson, Philippe; Winker, David M.; Kato, Seiji

    2017-12-01

    According to climate model simulations, the changing altitude of middle and high clouds is the dominant contributor to the positive global mean longwave cloud feedback. Nevertheless, the mechanisms of this longwave cloud altitude feedback and its magnitude have not yet been verified by observations. Accurate, stable, and long-term observations of a metric-characterizing cloud vertical distribution that are related to the longwave cloud radiative effect are needed to achieve a better understanding of the mechanism of longwave cloud altitude feedback. This study shows that the direct measurement of the altitude of atmospheric lidar opacity is a good candidate for the necessary observational metric. The opacity altitude is the level at which a spaceborne lidar beam is fully attenuated when probing an opaque cloud. By combining this altitude with the direct lidar measurement of the cloud-top altitude, we derive the effective radiative temperature of opaque clouds which linearly drives (as we will show) the outgoing longwave radiation. We find that, for an opaque cloud, a cloud temperature change of 1 K modifies its cloud radiative effect by 2 W m-2. Similarly, the longwave cloud radiative effect of optically thin clouds can be derived from their top and base altitudes and an estimate of their emissivity. We show with radiative transfer simulations that these relationships hold true at single atmospheric column scale, on the scale of the Clouds and the Earth's Radiant Energy System (CERES) instantaneous footprint, and at monthly mean 2° × 2° scale. Opaque clouds cover 35 % of the ice-free ocean and contribute to 73 % of the global mean cloud radiative effect. Thin-cloud coverage is 36 % and contributes 27 % of the global mean cloud radiative effect. The link between outgoing longwave radiation and the altitude at which a spaceborne lidar beam is fully attenuated provides a simple formulation of the cloud radiative effect in the longwave domain and so helps us to

  3. The pulmonary circulation of some domestic animals at high altitude

    Science.gov (United States)

    Anand, I.; Heath, D.; Williams, D.; Deen, M.; Ferrari, R.; Bergel, D.; Harris, P.

    1988-03-01

    Pulmonary haemodynamics and the histology of the pulmonary vasculature have been studied at high altitude in the yak, in interbreeds between yaks and cattle, and in domestic goats and sheep indigenous to high altitudes together with crosses between them and low-altitude strains. Cattle at high altitude had a higher pulmonary arterial pressure than cattle at low altitude. The yak and two interbreeds with cattle (dzos and stols) had a low pulmonary arterial pressure compared with cattle, while the medial thickness of the small pulmonary arteries was less than would be expected in cattle, suggesting that the yak has a low capacity for hypoxic pulmonary vasoconstriction and that this characteristic is transmitted genetically. Goats and sheep showed haemodynamic evidence of a limited response of the pulmonary circulation to high altitude, but no evidence that the high altitude breeds had lost this response. There were no measurable differences in the thickness of the media of the small pulmonary arteries between high- and low-altitude breeds of goats and sheep. All these species showed prominent intimal protrusions of muscle into the pulmonary veins but no specific effect of high altitude in this respect.

  4. 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....

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

    Science.gov (United States)

    Gonzales, Gustavo F

    2011-03-01

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

  6. Global Assessment of High-Altitude Wind Power

    OpenAIRE

    Archer, Cristina L.; Ken Caldeira

    2009-01-01

    The available wind power resource worldwide at altitudes between 500 and 12,000 m above ground is assessed for the first time. Twenty-eight years of wind data from the reanalyses by the National Centers for Environmental Prediction and the Department of Energy are analyzed and interpolated to study geographical distributions and persistency of winds at all altitudes. Furthermore, intermittency issues and global climate effects of large-scale extraction of energy from high-altitude winds are i...

  7. 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.

  8. 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

  9. Milk at altitude: Human milk macronutrient composition in a high-altitude adapted population of Tibetans.

    Science.gov (United States)

    Quinn, Elizabeth A; Diki Bista, Kesang; Childs, Geoff

    2016-02-01

    The physiological challenges of high altitude have led to population-specific patterns of adaptation. These include alterations to child growth and reproduction, including lactation. However, while breastfeeding has been investigated, nothing is known about milk composition in high altitude adapted populations. Here, we investigate milk macronutrient composition, volume, and energy in a sample of 82 Tibetans living at high and low altitude in rural villages (Nubri Valley, Nepal) and at low altitude in Kathmandu, Nepal. Milk samples were collected in the morning using hand expression, frozen, and assayed for fat, protein, and total sugars. Reproductive histories and health recalls were also collected. Milk fat averaged 5.2 ±2.0 g/100 mL, milk sugar 7.37 ± 0.49 g/100 mL, and milk protein 1.26 ± 0.35 g/100 mL for a mean energy density of 81.4 ± 17.4 kcal/100 mL. There were no associations between altitude of residence and milk composition; however, overall milk fat was high compared to reference populations. Within the three groups, milk fat was positively associated with infant age (B = 0.103; p milk sugar was significantly and inversely associated with maternal parity and triceps skinfold thickness. Milk fat, and consequently milk energy, may be increased in high-altitude adapted Tibetans when compared to populations living at low altitude. The association between milk fat and maternal adiposity suggests that milk composition may be sensitive to maternal adiposity in this sample, likely reflecting increased metabolic costs of producing a high-fat milk. © 2015 Wiley Periodicals, Inc.

  10. Genetic adaptation to high altitude in the Ethiopian highlands.

    Science.gov (United States)

    Scheinfeldt, Laura B; Soi, Sameer; Thompson, Simon; Ranciaro, Alessia; Woldemeskel, Dawit; Beggs, William; Lambert, Charla; Jarvis, Joseph P; Abate, Dawit; Belay, Gurja; Tishkoff, Sarah A

    2012-01-20

    Genomic analysis of high-altitude populations residing in the Andes and Tibet has revealed several candidate loci for involvement in high-altitude adaptation, a subset of which have also been shown to be associated with hemoglobin levels, including EPAS1, EGLN1, and PPARA, which play a role in the HIF-1 pathway. Here, we have extended this work to high- and low-altitude populations living in Ethiopia, for which we have measured hemoglobin levels. We genotyped the Illumina 1M SNP array and employed several genome-wide scans for selection and targeted association with hemoglobin levels to identify genes that play a role in adaptation to high altitude. We have identified a set of candidate genes for positive selection in our high-altitude population sample, demonstrated significantly different hemoglobin levels between high- and low-altitude Ethiopians and have identified a subset of candidate genes for selection, several of which also show suggestive associations with hemoglobin levels. We highlight several candidate genes for involvement in high-altitude adaptation in Ethiopia, including CBARA1, VAV3, ARNT2 and THRB. Although most of these genes have not been identified in previous studies of high-altitude Tibetan or Andean population samples, two of these genes (THRB and ARNT2) play a role in the HIF-1 pathway, a pathway implicated in previous work reported in Tibetan and Andean studies. These combined results suggest that adaptation to high altitude arose independently due to convergent evolution in high-altitude Amhara populations in Ethiopia.

  11. Preterm birth risk at high altitude in Peru.

    Science.gov (United States)

    Levine, Lisa D; Gonzales, Gustavo F; Tapia, Vilma L; Gasco, Manuel; Sammel, Mary D; Srinivas, Sindhu K; Ludmir, Jack

    2015-02-01

    High altitude has been implicated in a variety of adverse pregnancy outcomes including preeclampsia and stillbirth. Smaller studies show conflicting data on the association between high altitude and preterm birth (PTB). The objective of this study was to assess the association between altitude and PTB. A retrospective cohort study was performed using data from the Perinatal Information System, which includes deliveries from 43 hospitals in Peru from 2000 through 2010. Altitude was classified into the following categories: low (0-1999 m), moderate (2000-2900 m), and high (3000-4340 m). The primary outcome was PTB (delivery <37 weeks). Secondary outcomes were cesarean delivery and small for gestational age (SGA). Deliveries less than 23 weeks are not included in the database. χ(2) analyses were performed to compare categorical variables, and a logistic regression was used to calculate the odds ratios and control for confounders. Clustering by hospital was accounted for using generalized estimating equations. A total of 550,166 women were included (68% low, 15% moderate, 17% high altitude). The overall PTB rate was 5.9%, with no difference in the PTB rate among the 3 altitudes (5.6%, 6.2%, 6.8%, P = .13). There was a significant difference in cesarean rates (28.0%, 26.6%, 20.6%, P < .001) with a 34% decreased risk at high vs low altitude adjusted for confounders (adjusted odds ratio, 0.66; 95% confidence interval, 0.51-0.85). There was a difference in SGA (3.3%, 3.6%, 5.0%, P = .02) with a 51% increased risk at high vs low altitude adjusted for confounders (adjusted odds ratio, 1.49; 95% confidence interval, 1.14-1.93). High altitude is not associated with PTB. At high altitude, the cesarean rate was reduced and the SGA rate was increased. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Accuracy of Handheld Blood Glucose Meters at High Altitude

    NARCIS (Netherlands)

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

    2010-01-01

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

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

    NARCIS (Netherlands)

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

    2000-01-01

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

  14. 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.

  15. Lipid Subhyaloid Maculopathy and Exposure to High Altitude.

    Science.gov (United States)

    Petrocinio, Roberta Rosas; Gomes, Elga Dias

    High altitude retinopathy (HAR) includes a number of diseases related to high altitude such as acute mountain sickness (AMS), high altitude pulmonary edema (HAPE) and high altitude cerebral edema (HACE). High altitude retinopathy is mainly characterized by retinal hemorrhages, usually sparing the macular region, a condition specifically known as high altitude retinal hemorrhages (HARH). The pathogenesis of HARH is unclear. Many studies show that lack of oxygen causes an inadequate autoregulation of retinal circulation, causing vascular incompetence. Other retinal changes described in HAR have been reported, such as optical disk edema, optic disc hyperemia, cotton wool exudates, venous occlusions, and macular edema. In this paper we present a case of an aviator who developed a unilateral maculopathy through subhyaloid lipid accumulation on a climb to the top of Mt. Everest. The clinical findings are suggestive of an apparent case of temporary altitude-induced visual disruption maybe by the same presumable pathogenesis of HARH. Right eye visual loss was perceived at 5150 m when he was trying to take a photograph 40 d into the expedition. The maculopathy developed by this patient adds to the discussion on the pathogenesis of HARH, especially the aspect of this maculopathy and its complete resolution. It seems that autoregulation failure could lead to exudation and lipid deposits in the foveal area. Although macular damage is not a common signal in HARH, checking visual acuity during high altitude expeditions remains an important procedure to avoid late diagnosis as unilateral blindness may not be detected early. Rosas Petrocinio R, Gomes ED. Lipid subhyaloid maculopathy and exposure to high altitude. Aerosp Med Hum Perform. 2016; 87(10):898-900.

  16. Genetic adaptation to high altitude in the Ethiopian highlands

    OpenAIRE

    Scheinfeldt, Laura B.; Soi, Sameer; Thompson, Simon; Ranciaro, Alessia; Woldemeskel, Dawit; Beggs, William; Lambert, Charla; Jarvis, Joseph P.; Abate, Dawit; Belay, Gurja; Tishkoff, Sarah A.

    2012-01-01

    Background Genomic analysis of high-altitude populations residing in the Andes and Tibet has revealed several candidate loci for involvement in high-altitude adaptation, a subset of which have also been shown to be associated with hemoglobin levels, including EPAS1, EGLN1, and PPARA, which play a role in the HIF-1 pathway. Here, we have extended this work to high- and low-altitude populations living in Ethiopia, for which we have measured hemoglobin levels. We genotyped the Illumina 1M SNP ar...

  17. HIGH ALTITUDES EFFECTS ON HEMATOLOGIC BLOOD PARAMETERS

    OpenAIRE

    Hasim Rushiti; Florian Miftari; Besim Halilaj

    2015-01-01

    The approach and the objective of this experiment are consistent with the determination of changes of blood parameters after the stay of the students at an altitude of 1800-2300 meters, for a ten-day long ski course. In this paper are included a total of 64 students of the Faculty of Sport Sciences in Prishtina, of the age group of 19-25 (the average age is 21). All students previously have undergone a medical check for TA, arterial pulse and respiratory rate. In particular, the health situat...

  18. Physiology and pathophysiology at high altitude: considerations for the anesthesiologist.

    Science.gov (United States)

    Leissner, Kay B; Mahmood, Feroze U

    2009-01-01

    Millions of people live in, work in, and travel to areas of high altitude (HA). Skiers, trekkers, and mountaineers reach altitudes of 2500 m to more than 8000 m for recreation, and sudden ascents to high altitude without the benefits of acclimatization are increasingly common. HA significantly affects the human body, especially the cardiovascular and pulmonary systems, because of oxygen deprivation due to decreased ambient barometric pressure. Rapid ascents may lead to high-altitude diseases that sometimes have fatal consequences. Other factors, such as severe cold, dehydration, high winds, and intense solar radiation, increase the morbidity of patients at HA. Anesthesiologists working in or visiting areas of higher elevations should become familiar with the human physiology, altered pharmacology, and disease pattern of HA.

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

    CSIR Research Space (South Africa)

    Piketh, SJ

    1999-01-01

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

  20. 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...

  1. High-altitude wind resources in the Middle East

    National Research Council Canada - National Science Library

    Chak Man Andrew Yip; Udaya Bhaskar Gunturu; Georgiy L Stenchikov

    2017-01-01

    In the Middle East, near-surface wind resources are intermittent. However, high-altitude wind resources are abundant, persistent, and readily available and may provide alternative energy resources in this fossil-fuel-dependent region...

  2. NAMMA HIGH ALTITUDE MMIC SOUNDING RADIOMETER (HAMSR) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The NAMMA High Altitude MMIC Sounding Radiometer (HAMSR) dataset consists of data collected by HAMSR, which is a 25-channel microwave atmospheric sounder operating...

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

    Directory of Open Access Journals (Sweden)

    Amry Daulat Gultom

    2016-07-01

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

  4. Energy metabolism and the high-altitude environment.

    Science.gov (United States)

    Murray, Andrew J

    2016-01-01

    At high altitude the barometric pressure falls, challenging oxygen delivery to the tissues. Thus, whilst hypoxia is not the only physiological stress encountered at high altitude, low arterial P(O2) is a sustained feature, even after allowing adequate time for acclimatization. Cardiac and skeletal muscle energy metabolism is altered in subjects at, or returning from, high altitude. In the heart, energetic reserve falls, as indicated by lower phosphocreatine-to-ATP ratios. The underlying mechanism is unknown, but in the hypoxic rat heart fatty acid oxidation and respiratory capacity are decreased, whilst pyruvate oxidation is also lower after sustained hypoxic exposure. In skeletal muscle, there is not a consensus. With prolonged exposure to extreme high altitude (>5500 m) a loss of muscle mitochondrial density is seen, but this was not observed in a simulated ascent of Everest in hypobaric chambers. At more moderate high altitude, decreased respiratory capacity may occur without changes in mitochondrial volume density, and fat oxidation may be downregulated, although this is not seen in all studies. The underlying mechanisms, including the possible role of hypoxia-signalling pathways, remain to be resolved, particularly in light of confounding factors in the high-altitude environment. In high-altitude-adapted Tibetan natives, however, there is evidence of natural selection centred around the hypoxia-inducible factor pathway, and metabolic features in this population (e.g. low cardiac phosphocreatine-to-ATP ratios, increased cardiac glucose uptake and lower muscle mitochondrial densities) share similarities with those in acclimatized lowlanders, supporting a possible role for the hypoxia-inducible factor pathway in the metabolic response of cardiac and skeletal muscle energy metabolism to high altitude. © 2015 The Authors. Experimental Physiology © 2015 The Physiological Society.

  5. Changes in plasma electrolytes during acclimatization at high altitude.

    Science.gov (United States)

    Khan, D A; Aslam, M; Khan, Z U

    1996-06-01

    The effects on plasma electrolytes and related hormones were determined in non-acclimatized low lander males, exposed for 96 hours to an altitude of 4424 meters. Twenty healthy soldiers aged 18-34 years travelled by road from an altitude of 2303 meters to 4424 meters over a period of 10 hours. Plasma sodium levels (142.09 +/- 1.14 mmol/1) and aldosterone (16.61 +/- 5.70 ng/ml) decreased to 139.69 mmol/1 and 11.6 +/- 4.60 ug/ml respectively after 96 hours of acute exposure to high altitude (p electrolytes.

  6. Global Assessment of High-Altitude Wind Power

    Directory of Open Access Journals (Sweden)

    Cristina L. Archer

    2009-05-01

    Full Text Available The available wind power resource worldwide at altitudes between 500 and 12,000 m above ground is assessed for the first time. Twenty-eight years of wind data from the reanalyses by the National Centers for Environmental Prediction and the Department of Energy are analyzed and interpolated to study geographical distributions and persistency of winds at all altitudes. Furthermore, intermittency issues and global climate effects of large-scale extraction of energy from high-altitude winds are investigated.

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

    Energy Technology Data Exchange (ETDEWEB)

    Fry, R.J.M.

    1993-04-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Fry, R.J.M.

    1993-01-01

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

  9. High altitude leaders mapped by the Colombia lightning mapping array

    OpenAIRE

    Montañá Puig, Juan; López Trujillo, Jesús Alberto; Van der Velde, Oscar Arnoud; Romero Durán, David; Fabró Tàpia, Ferran

    2016-01-01

    On April 2015 a Lightning Mapping Array network (COL-LMA) was installed at the north of Colombia. This network provides 3D mapping of the development of lightning leaders. For the first time such network has been setup in the tropics. That allows us to investigate the high altitude development of lightning leaders. Here we present the results of the first measurements to confirm that negative leaders at altitudes of 15 km are common in the observed thunderstorms.

  10. Ambulatory blood pressure in untreated and treated hypertensive patients at high altitude: the High Altitude Cardiovascular Research-Andes study.

    Science.gov (United States)

    Bilo, Grzegorz; Villafuerte, Francisco C; Faini, Andrea; Anza-Ramírez, Cecilia; Revera, Miriam; Giuliano, Andrea; Caravita, Sergio; Gregorini, Francesca; Lombardi, Carolina; Salvioni, Elisabetta; Macarlupu, Jose Luis; Ossoli, Deborah; Landaveri, Leah; Lang, Morin; Agostoni, Piergiuseppe; Sosa, José Manuel; Mancia, Giuseppe; Parati, Gianfranco

    2015-06-01

    Blood pressure increases during acute exposure to high altitude in healthy humans. However, little is known on altitude effects in hypertensive subjects or on the treatment efficacy in this condition. Objectives of High Altitude Cardiovascular Research (HIGHCARE)-Andes Lowlanders Study were to investigate the effects of acute high-altitude exposure on 24-hour ambulatory blood pressure in hypertensive subjects and to assess antihypertensive treatment efficacy in this setting. One hundred untreated subjects with mild hypertension (screening blood pressure, 144.1±9.8 mm Hg systolic, 92.0±7.5 mm Hg diastolic) were randomized to double-blind placebo or to telmisartan 80 mg+modified release nifedipine 30 mg combination. Twenty-four-hour ambulatory blood pressure monitoring was performed off-treatment, after 6 weeks of treatment at sea level, on treatment during acute exposure to high altitude (3260 m) and immediately after return to sea level. Eighty-nine patients completed the study (age, 56.4±17.6 years; 52 men/37 women; body mass index, 28.2±3.5 kg/m(2)). Twenty-four-hour systolic blood pressure increased at high altitude in both groups (placebo, 11.0±9 mm Hg; Pblood pressure both at sea level and at high altitude (147.9±11.1 versus 132.6±12.4 mm Hg for placebo versus treated; Pblood pressure, and for nighttime blood pressure. Treatment was well tolerated in all conditions. Our study demonstrates that (1) 24-hour blood pressure increases significantly during acute high-altitude exposure in hypertensive subjects and (2) treatment with angiotensin receptor blocker-calcium channel blocker combination is effective and safe in this condition. URL: http://www.clinicaltrials.gov. Unique identifier: NCT01830530. © 2015 American Heart Association, Inc.

  11. Conjunctival oxygen tension at high altitude.

    Science.gov (United States)

    Mader, T H; Friedl, K E; Mohr, L C; Bernhard, W N

    1987-01-01

    Transconjunctival oxygen tension (PcjO2) was studied using a hypobaric chamber and during mountaineering excursions. Measurements obtained during acute chamber exposures (15-20 min) at sea level, 1829 m (6,000 ft), 3048 m (10,000 ft), 4267 m (14,000 ft) and return to sea level were (means +/- SEM): 60.1 +/- 2.7, 49.1 +/- 1.8, 38.3 +/- 2.4, 27.4 +/- 1.5, and 61.1 +/- 2.8 mm Hg, respectively (n = 13). The ratio of PcjO2 to arterial blood oxygen tension (PaO2) did not change in a consistent manner between sea level and 4267 m; PcjO2 was 74 +/- 6.9% of PaO2. The 16 subjects participating in the mountaineering phase of the study revealed similar means at sea level and 1829 m (57.4 +/- 2.4 and 46.3 +/- 1.9 mm Hg respectively), but a smaller decrement was observed at 3048 m (43.0 +/- 1.6 mm Hg). The difference between mountain and chamber values may be accounted for by a partial acclimatization to altitude brought about by longer exposure on the mountain excursions. A comparison between PcjO2 and transcutaneous oxygen tension during the chamber study suggests that a greater precision and sensitivity is obtained with measurement of oxygen tension at the conjunctival site. PcjO2 measurement is a non-invasive reflection of PaO2 which is suitable for continuous monitoring during hypoxia studies.

  12. Andean and Tibetan patterns of adaptation to high altitude.

    Science.gov (United States)

    Bigham, Abigail W; Wilson, Megan J; Julian, Colleen G; Kiyamu, Melisa; Vargas, Enrique; Leon-Velarde, Fabiola; Rivera-Chira, Maria; Rodriquez, Carmelo; Browne, Vaughn A; Parra, Esteban; Brutsaert, Tom D; Moore, Lorna G; Shriver, Mark D

    2013-01-01

    High-altitude hypoxia, or decreased oxygen levels caused by low barometric pressure, challenges the ability of humans to live and reproduce. Despite these challenges, human populations have lived on the Andean Altiplano and the Tibetan Plateau for millennia and exhibit unique circulatory, respiratory, and hematological adaptations to life at high altitude. We and others have identified natural selection candidate genes and gene regions for these adaptations using dense genome scan data. One gene previously known to be important in cellular oxygen sensing, egl nine homolog 1 (EGLN1), shows evidence of positive selection in both Tibetans and Andeans. Interestingly, the pattern of variation for this gene differs between the two populations. Continued research among Tibetan populations has identified statistical associations between hemoglobin concentration and single nucleotide polymorphism (SNP) genotype at EGLN1 and a second gene, endothelial PAS domain protein 1 (EPAS1). To measure for the effects of EGLN1 and EPAS1 altitude genotypes on hemoglobin concentration among Andean highlanders, we performed a multiple linear regression analysis of 10 candidate SNPs in or near these two genes. Our analysis did not identify significant associations between EPAS1 or EGLN1 SNP genotypes and hemoglobin concentration in Andeans. These results contribute to our understanding of the unique set of adaptations developed in different highland groups to the hypoxia of high altitude. Overall, the results provide key insights into the patterns of genetic adaptation to high altitude in Andean and Tibetan populations. Copyright © 2013 Wiley Periodicals, Inc.

  13. High-Altitude, Long-Endurance Airships for Coastal Surveillance

    Science.gov (United States)

    Dolce, James L.; Collozza, Anthony

    2005-01-01

    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 applications and background of this type of concept vehicle, reviews the history of high altitude flight and provides a point design analysis. The capabilities and limitations of the airship are demonstrated and possible solutions are proposed. Factors such as time of year, latitude, wind speeds, and payload are considered in establishing the capabilities of the airship. East and west coast operation is 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. Results on power system requirements for year long operation is presented.

  14. Rare Particle Searches with the high altitude SLIM experiment

    CERN Document Server

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

    2005-01-01

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

  15. Convergent Evolution of Rumen Microbiomes in High-Altitude Mammals.

    Science.gov (United States)

    Zhang, Zhigang; Xu, Dongming; Wang, Li; Hao, Junjun; Wang, Jinfeng; Zhou, Xin; Wang, Weiwei; Qiu, Qiang; Huang, Xiaodan; Zhou, Jianwei; Long, Ruijun; Zhao, Fangqing; Shi, Peng

    2016-07-25

    Studies of genetic adaptation, a central focus of evolutionary biology, most often focus on the host's genome and only rarely on its co-evolved microbiome. The Qinghai-Tibetan Plateau (QTP) offers one of the most extreme environments for the survival of human and other mammalian species. Yaks (Bos grunniens) and Tibetan sheep (T-sheep) (Ovis aries) have adaptations for living in this harsh high-altitude environment, where nomadic Tibetan people keep them primarily for food and livelihood [1]. Adaptive evolution affects energy-metabolism-related genes in a way that helps these ruminants live at high altitude [2, 3]. Herein, we report convergent evolution of rumen microbiomes for energy harvesting persistence in two typical high-altitude ruminants, yaks and T-sheep. Both ruminants yield significantly lower levels of methane and higher yields of volatile fatty acids (VFAs) than their low-altitude relatives, cattle (Bos taurus) and ordinary sheep (Ovis aries). Ultra-deep metagenomic sequencing reveals significant enrichment in VFA-yielding pathways of rumen microbial genes in high-altitude ruminants, whereas methanogenesis pathways show enrichment in the cattle metagenome. Analyses of RNA transcriptomes reveal significant upregulation in 36 genes associated with VFA transport and absorption in the ruminal epithelium of high-altitude ruminants. Our study provides novel insights into the contributions of microbiomes to adaptive evolution in mammals and sheds light on the biological control of greenhouse gas emissions from livestock enteric fermentation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. High-Altitude Cirrus Clouds and Climate

    Indian Academy of Sciences (India)

    2002-12-03

    Dec 3, 2002 ... At very low temperatures (~-70°C) prevailing near the tropical tropopause, aerosols and water vapour coagulate or get frozen into ice-cloud particles. When the cirrus clouds melt, water vapour and aerosols separate out, leaving large relative humidity and high aerosol content in the upper troposphere.

  17. Mood changes at very high altitudes in Pakistan

    Science.gov (United States)

    Ahmad, Sabih; Hussain, Sadiq

    2017-01-01

    Objective: To screen out psychiatric ‘cases’ and find the frequency of anxiety and depression symptoms in military volunteers performing duties at very high altitudes in the Karakoram ranges of Pakistan. Methods: This was a descriptive study lasting from Jan 2015 to June 2015, on volunteers serving at very high altitude, using General Health Questionnaire-12 (GHQ-12) and Hospital Anxiety and Depression Scale (HADS), Urdu versions. Analysis involved descriptive, inferential techniques and Bonferroni test. Demographic variables were compared to the scores. Results: A high percentage of the military volunteers screened positive for psychiatric ‘caseness’ and symptoms of anxiety and depression; mostly in the mild to moderate range, while very few of them reported severe symptoms. Demographic variables such as marital status, number of children, positive family psychiatric history, past medical history, duration at high altitude and educational levels were found to be significant risk factors for developing symptoms of anxiety and depression. Conclusions: Individuals performing duties at very high altitude, experience symptoms of anxiety and depression, their demographics are important in understanding their emotional problems. PMID:28367206

  18. 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.

  19. Soldier at High Altitude: Problem & Preventive Measures

    OpenAIRE

    S. S. Purkayastha; W. Selvamurthy

    2000-01-01

    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...

  20. Utilization of Wind Energy at High Altitude

    OpenAIRE

    Bolonkin, Alexander

    2007-01-01

    Ground based, wind energy extraction systems have reached their maximum capability. The limitations of current designs are: wind instability, high cost of installations, and small power output of a single unit. The wind energy industry needs of revolutionary ideas to increase the capabilities of wind installations. This article suggests a revolutionary innovation which produces a dramatic increase in power per unit and is independent of prevailing weather and at a lower cost per unit of energ...

  1. 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

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

    Indian Academy of Sciences (India)

    2014-07-08

    Jul 8, 2014 ... inventory of Indian Space Research Organisation (2011), a total of 272 high altitude lakes covering an area of 617 ha are present in Himachal Pradesh ...... diatoms flora of four lakes and ponds from the Windmill Islands,. East Antarctica. Antarct. Sci. 13 410–419. Sabbe K, Hodgson DA, Verleyen E, Taton A, ...

  3. Reduced autonomic activity during stepwise exposure to high altitude

    NARCIS (Netherlands)

    Sevre, K; Bendz, B; Hanko, E; Nakstad, AR; Hauge, A; Kasin, JI; Lefrandt, JD; Smit, AJ; Eide, [No Value; Rostrup, M

    2001-01-01

    Several studies have shown increased sympathetic activity during acute exposure to hypobaric hypoxia. In a recent field study we found reduced plasma catecholamines during the first days after a stepwise ascent to high altitude. In the present study 14 subjects were exposed to a simulated ascent in

  4. Abnormal blood flow in the sublingual microcirculation at high altitude

    NARCIS (Netherlands)

    Martin, Daniel S.; Ince, Can; Goedhart, Peter; Levett, Denny Z. H.; Grocott, Mike P. W.

    2009-01-01

    We report the first direct observations of deranged microcirculatory blood flow at high altitude, using sidestream dark-field imaging. Images of the sublingual microcirculation were obtained from a group of 12 volunteers during a climbing expedition to Cho Oyu (8,201 m) in the Himalayas.

  5. Acute occlusive mesenteric ischemia in high altitude of ...

    African Journals Online (AJOL)

    Background and Objectives: Mesenteric ischemia which can be acute or chronic depending on the rapidity of compromised blood flow produces bowel ischemia, infarction, bacterial transmigration, endotoxemia, multisystem organ failure and death. High altitude can precipitate thrombosis because of hypobaric hypoxia and ...

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

    DEFF Research Database (Denmark)

    Sutton, J R; Lassen, N

    1979-01-01

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

  7. Regulation of blood volume in lowlanders exposed to high altitude

    DEFF Research Database (Denmark)

    Siebenmann, Christoph; Robach, Paul; Lundby, Carsten

    2017-01-01

    Humans ascending to high altitude (HA) experience a reduction in arterial oxyhemoglobin saturation and, as a result, arterial O2 content ([Formula: see text]). As HA exposure extends, this reduction in [Formula: see text] is counteracted by an increase in arterial hemoglobin concentration. Initia...

  8. Climate Change Impacts on High-Altitude Ecosystems

    Directory of Open Access Journals (Sweden)

    Harald Pauli

    2016-02-01

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

  9. 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

  10. High altitude genetic adaptation in Tibetans: no role of increased hemoglobin-oxygen affinity

    OpenAIRE

    Tashi, Tsewang; Feng, Tang; Koul, Parvaiz; Amaru, Ricardo; Hussey, Dottie; Lorenzo, Felipe R.; Rili, Ge; Prchal, Josef T.

    2014-01-01

    High altitude exerts selective evolutionary pressure primarily due to its hypoxic environment, resulting in multiple adaptive responses. High hemoglobin-oxygen affinity is postulated to be one such adaptive change, which has been reported in Sherpas of the Himalayas. Tibetans have lived on the Qinghai-Tibetan plateau for thousands of years and have developed unique phenotypes, such as protection from polycythemia which has been linked to PDH2 mutation, resulting in downregulation of HIF pathw...

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

    Science.gov (United States)

    Brutsaert, Tom

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

  12. Efficacy of Conventional and High-Frequency Ventilation at Altitude

    Science.gov (United States)

    1988-12-01

    evacuation; Mechanical ventilation ;--andL If.’jJI t’ 06 I 12 i ~High-Frequency ventilation ’& ~.~.- 19 ABSTRACT (Continue on reverse If neesry and identify by...The inspired gas and the subsequent rate of appearance of these gases in arterial blood were monitored. With conventional mechanical ventilation (CMV...AND HIGH-FREQUENCY VENTILATION AT ALTITUDE INTRODUCTION The logistics of aeromedical evacuation of patients requiring mechanical ventilation is

  13. Tear Break-up Time in High Altitude Areas.

    Science.gov (United States)

    Jha, K N

    2009-01-01

    In high altitude areas, patients report with irritation, redness and foreign body sensation in their eyes suggesting tear film abnormality due to low humidity and windy environmental conditions. Tear Break- up Time (TBUT) was studied in 100 subjects consisting of local population and those originally from plains residing in high altitude areas in Ladakh. There were 24% individuals with TBUT of 10 seconds. In symptomatic patients with TBUT of <5 seconds, eight cases had irritation of eyes, six foreign body sensation and two cases had pain, watering, irritation and redness of eyes. Pterygium was seen in 12 individuals and inter palpebral congestion in 4 cases. A total of 24% cases showed abnormal (<5 seconds) TBUT. Abnormality of tear film in the presence of low humidity and windy condition with high ultraviolet radiation may lead to ocular discomfort and pterygium in these areas.

  14. The University of Alberta High Altitude Balloon Program

    Science.gov (United States)

    Johnson, W.; Buttenschoen, A.; Farr, Q.; Hodgson, C.; Mann, I. R.; Mazzino, L.; Rae, J.; University of Alberta High Altitude Balloon Team

    2011-12-01

    The University of Alberta High Altitude Balloon (UA-HAB) program is a one and half year program sponsored by the Canadian Space Agency (CSA) that offers hands on experience for undergraduate and graduate students in the design, build, test and flight of an experimental payload on a high altitude balloon platform. Utilising low cost weather balloon platforms, and through utilisation of the CSA David Florida Laboratory for thermal-vacuum tests , in advance of the final flight of the payload on a NASA high altitude balloon platform. Collectively the program provided unique opportunities for students to experience mission phases which parallel those of a space satellite mission. The program has facilitated several weather balloon missions, which additionally provide educational opportunities for university students and staff, as well as outreach opportunities among junior and senior high school students. Weather balloon missions provide a cheap and quick alternative to suborbital missions; they can be used to test components for more expensive missions, as well as to host student based projects from different disciplines such as Earth and Atmospheric Sciences (EAS), Physics, and Engineering. In addition to extensive skills development, the program aims to promote recruitment of graduate and undergraduate students into careers in space science and engineering. Results from the UA-HAB program and the flight of the UA-HAB shielded Gieger counter payload for cosmic ray and space radiation studies will be presented. Lessons learned from developing and maintaining a weather balloon program will also be discussed. This project is undertaken in partnership with the High Altitude Student Platform, organized by Louisiana State University and the Louisiana Space Consortium (LaSpace), and sponsored by NASA, with the financial support of the Canadian Space Agency.

  15. 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.

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

    Science.gov (United States)

    Biondich, Amy Sue; Joslin, Jeremy D

    2015-12-01

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

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

    DEFF Research Database (Denmark)

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

    2003-01-01

    conditions. However, this fails to take into account that oxygen solubility declines with decreasing atmospheric pressure, which may be of importance at high altitudes. 2. Based on samples of macroinvertebrate benthos and in situ measurements of respiratory oxygen demand of macroinvertebrates in small...... of species and aquatic communities. We argue that oxygen deficiency may be a potentially important factor, and that more focus on this topic is likely to produce significant new insights in aquatic community ecology....

  18. Oxidative stress at high altitude: genotype–phenotype correlations

    OpenAIRE

    Pasha, Qadar; Pandey, Priyanka

    2014-01-01

    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, especia...

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

    OpenAIRE

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

    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 gro...

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

    Directory of Open Access Journals (Sweden)

    Qi-quan ZHOU

    2012-02-01

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

  1. High Altitude Balloon Real-time Landing Prediction

    Science.gov (United States)

    Eckel, Robert

    2010-10-01

    With the success of Weber State University's high altitude balloon program, HARBOR, missions become more complex and payloads of higher value, the importance of being able to recover the payload quickly after landing has increased. By expanding the functionality of Weber State's Multi-Sensor Array, combined with an amateur radio terminal node controller, we will be able to accurately predict the landing zone while in flight. Analysis of previous flights indicates that velocity vector projections on a plane tangential to the earth's surface remain fairly constant at any given altitude during the ascent and descent. By differentiating position data from GPS and other instruments during the ascent, the descent profile can be integrated to produce an accurate landing position. This prediction is then able to be sent down wirelessly over existing ham radio infrastructure to plot the predicted landing zone in navigation and mapping software in real time.

  2. Aerodynamic performance of osculating-cones waveriders at high altitudes

    Science.gov (United States)

    Graves, Rick Evan

    The steady-state aerodynamic characteristics of three-dimensional waverider configurations immersed in hypersonic rarefied flows are investigated. Representative geometries are generated using an inverse design procedure, the method of osculating cones, which defines an exit plane shock shape and approximates the flow properties of the compression surface by assuming that each spanwise station along the shock profile lies within a region of locally conical flow. Vehicle surface and flow field properties are predicted using the direct simulation Monte Carlo method, a probabilistic numerical scheme in which simulated molecules are followed through representative collisions with each other and solid surfaces, and subsequent deterministic displacement. The aerodynamic properties of high- and low-Reynolds number waverider geometries, optimized for maximum lift-to-drag ratio and subject to mission-oriented constraints, are contrasted with results from reference caret and delta wings with similar internal volumes to quantify the relevance and advantage of the waverider concept at high altitudes. The high-Reynolds number waverider, optimized for the continuum regime at Minfinity = 4 and Reinfinity = 250 million, was the focus of recent wind tunnel testing for near on-design and off-design conditions, including low subsonic speeds. The present work extends the previous analyses into the high-altitude regime. The low-Reynolds number waverider, optimized at Minfinity = 20 and Reinfinity = 2.5 million, is studied to determine if optimization potential exists for a high-Mach number waverider at high altitudes. A characteristic length of 5 m is assumed for both waverider configurations, representative of a hypersonic missile concept. The geometries are aerodynamically evaluated over a parametric space consisting of an altitude variation of 95 km to 150 km and an angle of attack range of --5° to 10°. The effect of off-design Mach number on the performance of the high

  3. 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...

  4. GRIP HIGH ALTITUDE IMAGING WIND AND RAIN AIRBORNE PROFILER (HIWRAP) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The GRIP High Altitude Imaging Wind and Rain Airborne Profiler (HIWRAP) dataset was collected by the High-Altitude Imaging Wind and Rain Airborne Profiler (HIWRAP),...

  5. High Altitude Venus Operations Concept Trajectory Design, Modeling and Simulation

    Science.gov (United States)

    Lugo, Rafael A.; Ozoroski, Thomas A.; Van Norman, John W.; Arney, Dale C.; Dec, John A.; Jones, Christopher A.; Zumwalt, Carlie H.

    2015-01-01

    A trajectory design and analysis that describes aerocapture, entry, descent, and inflation of manned and unmanned High Altitude Venus Operation Concept (HAVOC) lighter-than-air missions is presented. Mission motivation, concept of operations, and notional entry vehicle designs are presented. The initial trajectory design space is analyzed and discussed before investigating specific trajectories that are deemed representative of a feasible Venus mission. Under the project assumptions, while the high-mass crewed mission will require further research into aerodynamic decelerator technology, it was determined that the unmanned robotic mission is feasible using current technology.

  6. High altitude smoke in the NASA GISS GCM

    Science.gov (United States)

    Field, Robert; Luo, M.; Fromm, M.; Voulgarakis, A.; Mangeon, S.; Worden, J.

    2015-01-01

    High altitude smoke-plumes from large, explosive fires were discovered in the late 1990sThey can now be observed with unprecedented detail from space-borne instruments with high vertical resolution in the UTLS such as CALIOP, MLS and ACE. These events inject large quantities of pollutants into a relatively clean and dry environment They serve as unique natural experiments with which to understand, using chemical transport and composition-climate models, the chemical and radiative impacts of long-lived biomass burning emissions. We are currently studying the Black Saturday bushfires in Australia during February 2009

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

    NARCIS (Netherlands)

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

    2011-01-01

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

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

    NARCIS (Netherlands)

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

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

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

    Science.gov (United States)

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

    2016-06-01

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

  10. 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

  11. Schistosomiasis transmission at high altitude crater lakes in Western Uganda

    Directory of Open Access Journals (Sweden)

    Philbert Clouds

    2008-08-01

    Full Text Available Abstract Background Contrary to previous reports which indicated no transmission of schistosomiasis at altitude >1,400 m above sea level in Uganda, in this study it has been established that schistosomiasis transmission can take place at an altitude range of 1487–1682 m above sea level in western Uganda. Methods An epidemiological survey of intestinal schistosomiasis was carried out in school children staying around 13 high altitude crater lakes in Western Uganda. Stool samples were collected and then processed with the Kato-Katz technique using 42 mg templates. Thereafter schistosome eggs were counted under a microscope and eggs per gram (epg of stool calculated. A semi-structured questionnaire was used to obtain demographic data and information on risk factors. Results 36.7% of the pupils studied used crater lakes as the main source of domestic water and the crater lakes studied were at altitude ranging from 1487–1682 m above sea level. 84.6% of the crater lakes studied were infective with over 50% of the users infected. The overall prevalence of Schistosoma mansoni infection was 27.8% (103/370 with stool egg load ranging from 24–6048 per gram of stool. 84.3%( 312 had light infections (400 egg/gm of stool. Prevalence was highest in the age group 12–14 years (49.5% and geometric mean intensity was highest in the age group 9–11 years (238 epg. The prevalence and geometric mean intensity of infection among girls was lower (26%; 290 epg compared to that of boys (29.6%; 463 epg (t = 4.383, p Conclusion and recommendations The altitudinal threshold for S. mansoni transmission in Uganda has changed and use of crater water at an altitude higher than 1,400 m above sea level poses a risk of acquiring S. mansoni infection in western Uganda. However, further research is required to establish whether the observed altitudinal threshold change is as a result of climate change or other factors. It is also necessary to establish the impact this could

  12. Mössbauer studies of hemoglobin in high altitude polycythemia

    Science.gov (United States)

    Xiufang, Zhang; Linming, Shen; Songsen, Chen; Yuanyuan, Liu; Naifei, Gao; Yuanming, Zheng; Zhaohui, Ao; Liangquan, Shong

    1990-07-01

    The Mössbauer spectra have been measured in erythrocytes from normal adults and the patients with high altitude polycythemia (HAPC). The results indicated that two subspectra “a” and “b”, corresponding to oxy- and deoxyhemoglobin respectively, were present in all blood samples, and a third subspectrum “c” was found to exist in almost all samples from the patients. The parameters of the third subspectra “cl” in most samples from the patients were similar to those of carbon monoxyhemoglobin. The components were considered to be the denatured hemoglobin in RBCs (red blood cells). Together with clinical analysis, a possible mechanism of HAPC has been discussed.

  13. Animal-habitat relationships in high altitude rangelands

    OpenAIRE

    Singh, Navinder J.

    2008-01-01

    The papers of the thesis are not available in Munin: 1. Navinder J Singh, Nigel G Yoccoz, Nicolas Lecomte, Steeve D Côté and Joseph L Fox: «Scale and selection of habitat and resources: Tibetan argali in high altitude rangelands» (manuscript). Published version, Can. J. Zool. 88: 436-447 (2010), available at http://dx.doi.org/10.1139/Z10-015 2. Navinder J Singh, Christophe Bonenfant, Nigel G Yoccoz and Steeve D Côté: «Proximate and ultimate causes of sexual segregation in eurasian w...

  14. Solar Energy Generation Model for High Altitude Long Endurance Platforms

    OpenAIRE

    Brizon, Mathilde

    2015-01-01

    For designing and evaluating new concepts for HALE platforms, the energy provided by solar cells is a key factor. The purpose of this thesis is to model the electrical power which can be harnessed by such a platform along any flight trajectory for different aircraft designs. At first, a model of the solar irradiance received at high altitude will be performed using the solar irradiance models already existing for ground level applications as a basis. A calculation of the efficiency of the energy g...

  15. WCDMA Uplink Interference Assessment from Multiple High Altitude Platform Configurations

    Directory of Open Access Journals (Sweden)

    Grace D

    2008-01-01

    Full Text Available Abstract We investigate the possibility of multiple high altitude platform (HAP coverage of a common cell area using a wideband code division multiple access (WCDMA system. In particular, we study the uplink system performance of the system. The results show that depending on the traffic demand and the type of service used, there is a possibility of deploying 3–6 HAPs covering the same cell area. The results also show the effect of cell radius on performance and the position of the multiple HAP base stations which give the worst performance.

  16. 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.

  17. Breathlessness at High Altitude: First Episode of Bronchoconstriction in an Otherwise Healthy Sojourner.

    Science.gov (United States)

    Bhandari, Sanjeeb Sudarshan; Koirala, Pranawa; Lohani, Sadichhya; Phuyal, Pratibha; Basnyat, Buddha

    2017-06-01

    Bhandari, Sanjeeb Sudarshan, Pranawa Koirala, Sadichhya Lohani, Pratibha Phuyal, and Buddha Basnyat. Breathlessness at high altitude: first episode of bronchoconstriction in an otherwise healthy sojourner. High Alt Med Biol.. 18:179-181, 2017-High-altitude illness is a collective term for less severe acute mountain sickness and more severe high-altitude pulmonary edema (HAPE) and high-altitude cerebral edema, which we can experience while traveling to high altitude. These get better when we get down to the lower altitudes. People with many comorbidities also have been traveling to high altitudes from the dawn of civilization. Obstructive airway diseases can be confused with HAPE at high altitude. Asthma is one of those obstructive pulmonary diseases, but it is shown to get better with travel to the altitudes higher than the residing altitude. We present a case of 55-year-old nonsmoker, athletic, female, a lowland resident who developed difficulty breathing for the first time at high altitude. She did not get better with the descent to lower altitude and timely intake of acetazolamide. Her pulmonary function test showed obstructive airway pattern, which got better with salbutamol/ipratropium nebulization and oxygen.

  18. Perseus High Altitude Remotely Piloted Aircraft on Ramp

    Science.gov (United States)

    1991-01-01

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

  19. High Altitude Electromagnetic Pulse (HEMP) and High Power Microwave (HPM) Devices: Threat Assessments

    Science.gov (United States)

    2008-07-21

    against HEMP effects resulting from a nuclear exchange.40 The Limited Test Ban Treaty of 1963 prohibits nuclear explosions in the atmosphere, in space, and...Order Code RL32544 High Altitude Electromagnetic Pulse ( HEMP ) and High Power Microwave (HPM) Devices: Threat Assessments Updated July 21, 2008 Clay...2008 to 00-00-2008 4. TITLE AND SUBTITLE High Altitude Electromagnetic Pulse ( HEMP ) and High Power Microwave (HPM) Devices: Threat Assessments 5a

  20. Perseus High Altitude Remotely Piloted Aircraft on Ramp

    Science.gov (United States)

    1991-01-01

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

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

    Science.gov (United States)

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

    2013-12-01

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

  2. High altitude pulmonary edema, down syndrome, and obstructive sleep apneas.

    Science.gov (United States)

    Richalet, Jean-Paul; Chenivesse, Cécile; Larmignat, Philippe; Meille, Laurent

    2008-01-01

    A 24-year-old adult with a Down syndrome was admitted in December 2006 at the Moutiers hospital in the French Alps for an acute inaugural episode of high altitude pulmonary edema (HAPE) that occurred in the early morning of day 3 after his arrival to La Plagne (2000 m). This patient presented an interventricular septal defect operated on at the age of 7, a hypothyroidism controlled by 50 microg levothyrox, a state of obesity (BMI 37.8 kg/m(2)), and obstructive sleep apneas with a mean of 42 obstructive apneas or hypopneas per hour, treated with continuous positive airway pressure (CPAP). The patient refused to use his CPAP during his stay in La Plagne. At echocardiography, resting parameters were normal, with a left ventricular, ejection fraction of 60%, a normokinetic right ventricle, and an estimated systolic pulmonary artery pressure (sPAP) of 30 mmHg. At exercise, sPAP rose to 45 mmHg and the right ventricle was still normokinetic and not dilated. An exercise hypoxic tolerance test performed at 60 W and at the equivalent altitude of 3300 m revealed a severe drop in arterial oxygen saturation down to 60%, with an abnormal low ventilatory response to hypoxia, suggesting a defect in peripheral chemosensitivity to hypoxia. In conclusion, patients with Down syndrome, including adults with no cardiac dysfunction and regular physical activity, are at risk of HAPE even at moderate altitude when they suffer from obstructive sleep apneas associated with obesity and low chemoresponsiveness. This observation might be of importance since an increasing number of young adults with Down syndrome participate in recreational or sport activities, including skiing and mountaineering.

  3. Reproduction in high altitude Aymara: physiological stress and fertility planning?

    Science.gov (United States)

    Crognier, E; Villena, M; Vargas, E

    2002-10-01

    Reproductive characteristics at high altitude are described based on the reproductive histories of 720 Aymara women, collected in 1998 and 1999 in a group of twelve peasant communities at a mean altitude of 4000 m in the Bolivian Altiplano. The reproductive pattern is shaped by a late onset of childbearing, associated with a rather short reproductive span and large birth intervals. Environmental conditions could explain the particularly late age at menarche of rural girls compared with their urban counterparts, whereas the age at first birth is likely to be under cultural control. The short reproductive span appears to result from a large mean interval between last birth and menopause, which is essentially determined by cultural decisions. The birth intervals, which are longer than in many traditional societies, could be the result of a slower restoration of postpartum fecundability induced by the hard way of life inherent in the Altiplano (including poor sanitary and nutritional conditions and high workload), perhaps aggravated by hypoxia. However, a secular trend in fertility is perceptible, towards earlier menarche, earlier age at first birth, increasing reproductive span and a slight increase in live births and surviving offspring, which is probably the result of a slow improvement in living conditions. The existence of birth control on the one hand, and a total fertility rate averaging six live births among the couples who do not practise contraception on the other, are other arguments against the hypothesis of a low natural fecundity in these Aymara groups.

  4. ER-2 High Altitude Solar Cell Calibration Flights

    Science.gov (United States)

    Myers, Matthew; Wolford, David; Snyder, David; Piszczor, Michael

    2015-01-01

    Evaluation of space photovoltaics using ground-based simulators requires primary standard cells which have been characterized in a space or near-space environment. Due to the high cost inherent in testing cells in space, most primary standards are tested on high altitude fixed wing aircraft or balloons. The ER-2 test platform is the latest system developed by the Glenn Research Center (GRC) for near-space photovoltaic characterization. This system offers several improvements over GRC's current Learjet platform including higher altitude, larger testing area, onboard spectrometers, and longer flight season. The ER-2 system was developed by GRC in cooperation with NASA's Armstrong Flight Research Center (AFRC) as well as partners at the Naval Research Laboratory and Air Force Research Laboratory. The system was designed and built between June and September of 2014, with the integration and first flights taking place at AFRC's Palmdale facility in October of 2014. Three flights were made testing cells from GRC as well as commercial industry partners. Cell performance data was successfully collected on all three flights as well as solar spectra. The data was processed using a Langley extrapolation method, and performance results showed a less than half a percent variation between flights, and less than a percent variation from GRC's current Learjet test platform.

  5. 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.

  6. High-altitude wind resources in the Middle East

    KAUST Repository

    Yip, Chak Man Andrew

    2017-08-23

    In the Middle East, near-surface wind resources are intermittent. However, high-altitude wind resources are abundant, persistent, and readily available and may provide alternative energy resources in this fossil-fuel-dependent region. Using wind field data from the Modern-Era Retrospective Analysis for Research and Applications Version 2 (MERRA-2), this study identifies areas favorable to the deployment of airborne wind energy (AWE) systems in the Middle East and computes the optimal heights at which such systems would best operate. AWE potential is estimated using realistic AWE system specifications and assumptions about deployment scenarios and is compared with the near-surface wind generation potential with respect to diurnal and seasonal variability. The results show the potential utility of AWE in areas in the Middle East where the energy demand is high. In particular, Oman and Saudi Arabia have a high level of the potential power generation with low annual variability.

  7. High-altitude wind resources in the Middle East.

    Science.gov (United States)

    Yip, Chak Man Andrew; Gunturu, Udaya Bhaskar; Stenchikov, Georgiy L

    2017-08-29

    In the Middle East, near-surface wind resources are intermittent. However, high-altitude wind resources are abundant, persistent, and readily available and may provide alternative energy resources in this fossil-fuel-dependent region. Using wind field data from the Modern-Era Retrospective Analysis for Research and Applications Version 2 (MERRA-2), this study identifies areas favorable to the deployment of airborne wind energy (AWE) systems in the Middle East and computes the optimal heights at which such systems would best operate. AWE potential is estimated using realistic AWE system specifications and assumptions about deployment scenarios and is compared with the near-surface wind generation potential with respect to diurnal and seasonal variability. The results show the potential utility of AWE in areas in the Middle East where the energy demand is high. In particular, Oman and Saudi Arabia have a high level of the potential power generation with low annual variability.

  8. The High Altitude Student Platform Status and Future Plans

    Science.gov (United States)

    Guzik, T. Gregory; Ellison, Steven B.; Gould, Randy; Granger, Douglas; Smith, Douglas; Stewart, Michael; Wefel, John P.

    The High Altitude Student Platform (HASP) is designed to carry multiple student payloads to an altitude of about 36 kilometers with flight durations of 15 to 20 hours using a small volume, zero pressure balloon. To date HASP has had two successful flights (2006, 2007) and is anticipating a third flight this September (2008). Including the upcoming flight, HASP has supported 29 student payloads from 15 institutions across the United States involving about 110 undergraduate and graduate students. By participating in a HASP flight, students gain practical, real-world experience in the design, fabrication, system testing, operation, data analysis and management of an aerospace payload. Such experiences are very difficult to achieve in a normal classroom setting and play an important role in training new aerospace scientists and engineers. During the flights, the HASP control systems have functioned exceptionally well and the modular electronics design has enabled us to maintain flexibility, improve reliability and decrease flight-line support expenses. These capabilities, plus new advances in miniaturized balloon vehicle control systems, may enable the overall weight of HASP to be significantly reduced potentially reducing launch costs and/or improving the student payload to system mass ratio. During the presentation we will discuss the HASP program, previous flights, science results / lessons learned from the student payloads and plans for improving the efficiency of future flights.

  9. Criteria for psychological adaptation to high-altitude hypoxia.

    Science.gov (United States)

    Bonnon, M; Noël-Jorand, M C; Therme, P

    1999-08-01

    The purpose of this study was to test an ascent program for ideal psychological adaptation to high altitudes. A psychological approach was used to test a model describing a gradual step-by-step ascent. Seven subjects spent nine days between 3,500 m and 4,400 m altitude, followed by eight days climbing 500 m each day from 3,500 m to 5,400 m. They performed a cognitive-motor task three times, once under normoxia, once under acute hypoxia, and once under chronic hypoxic conditions. Durations for these subjects were compared with those obtained by a control group tested under normoxia. Subjects' emotional state was assessed by analyzing their remarks during an interview conducted at 5,400 m and by calculating from the answers given to the three questions, a mood index for each subject. Analysis showed that the performances of both groups improved on the second and third administrations of the test. There was, however, no interaction between the group and the time of administration. Mood indexes indicated that the majority of the subjects had no trouble in adapting to the situation and few cognitive or emotional disturbances were observed. These findings may be attributed to the ascent being well designed and planned thereby preventing various possible forms of mountain sickness and other pathologies from developing in the subjects.

  10. Increased choroidal thickness in patient with high-altitude retinopathy

    Directory of Open Access Journals (Sweden)

    Kyoko Hirukawa-Nakayama

    2014-01-01

    Full Text Available We report a case of high-altitude retinopathy with increased choroidal thickness detected by spectral-domain optical coherence tomography (SD-OCT. A 36-year-old Japanese man developed an acute vision decrease in his left eye after he had trekked at an altitude of 4600 m in Tibet for 1 week. His visual acuity was 20/20 OD and 20/200 OS with refractive errors of − 0.25 diopters (D OD and − 0.50 D OS 3 weeks after the onset of the visual decrease. Funduscopic examinations revealed multiple intraretinal hemorrhages bilaterally and a macular hemorrhage in the left eye. SD-OCT showed that the thickness of choroidal layer at the fovea was 530 μm OD and 490 μm OS which is thicker than that in normal subjects of approximately 300 μm. We suggest that the increase in the retinal blood flow under hypoxic conditions may be associated with an increase in the choroidal blood flow resulting in an increase in choroidal thickness.

  11. Centurion solar-powered high-altitude aircraft in flight

    Science.gov (United States)

    1998-01-01

    Since 1980 AeroVironment, Inc. (founded in 1971 by the ultra-light airplane innovator--Dr. Paul MacCready) has been experimenting with solar-powered aircraft, often in conjunction with the NASA Dryden Flight Research Center, Edwards, California. Thus far, AeroVironment, now headquartered in Monrovia, California, has achieved several altitude records with its Solar Challenger, Pathfinder, and Pathfinder-Plus aircraft. It expects to exceed these records with the newer and larger solar-powered Centurion and its successors the Centelios and Helios vehicles, in the NASA Environmental Research Aircraft and Sensor Technology (ERAST) program. The Centurion is a lightweight, solar-powered, remotely piloted flying wing aircraft that is demonstrating the technology of applying solar power for long-duration, high-altitude flight. It is considered to be a prototype technology demonstrator for a future fleet of solar-powered aircraft that could stay airborne for weeks or months on scientific sampling and imaging missions or while serving as telecommunications relay platforms. Although it shares many of the design concepts of the Pathfinder, the Centurion has a wingspan of 206 feet, more than twice the 98-foot span of the original Pathfinder and 70-percent longer than the Pathfinder-Plus' 121-foot span. At the same time, Centurion maintains the 8-foot chord (front to rear distance) of the Pathfinder wing, giving the wing an aspect ratio (length-to-chord) of 26 to 1. Other visible changes from its predecessor include a modified wing airfoil designed for flight at extreme altitude and four underwing pods to support its landing gear and electronic systems (compared with two such pods on the Pathfinder). The flexible wing is primarily fabricated from carbon fiber, graphite epoxy composites, and kevlar. It is built in five sections, a 44-foot-long center section and middle and outer sections just over 40 feet long. All five sections have an identical thickness--12 percent of the chord

  12. 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.

  13. 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.

  14. High-Altitude Living Shapes the Skin Microbiome in Humans and Pigs

    Directory of Open Access Journals (Sweden)

    Bo Zeng

    2017-10-01

    Full Text Available While the skin microbiome has been shown to play important roles in health and disease in several species, the effects of altitude on the skin microbiome and how high-altitude skin microbiomes may be associated with health and disease states remains largely unknown. Using 16S rRNA marker gene sequencing, we characterized the skin microbiomes of people from two racial groups (the Tibetans and the Hans and of three local pig breeds (Tibetan pig, Rongchang pig, and Qingyu pig at high and low altitudes. The skin microbial communities of low-altitude pigs and humans were distinct from those of high-altitude pigs and humans, with five bacterial taxa (Arthrobacter, Paenibacillus, Carnobacterium, and two unclassified genera in families Cellulomonadaceae and Xanthomonadaceae consistently enriched in both pigs and humans at high altitude. Alpha diversity was also significantly lower in skin samples collected from individuals living at high altitude compared to individuals at low altitude. Several of the taxa unique to high-altitude humans and pigs are known extremophiles adapted to harsh environments such as those found at high altitude. Altogether our data reveal that altitude has a significant effect on the skin microbiome of pigs and humans.

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

    Directory of Open Access Journals (Sweden)

    Paul J. Anderson

    2011-01-01

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

  16. Women at Altitude: Effects of Menstrual Cycle Phase and Alpha-Adrenergic Blockade on High Altitude Acclimatization

    Science.gov (United States)

    1999-10-01

    and venous tone. Alpha 1-adrenergic blockade with prazosin attenuated the rise in SNS activity at 4,300 m and prevented the increase in PNS activity in...Physiol 1991;70(3):1129-36. 4. Zamudio S., S.K. Palmer, T.E. Dahms, et al. Blood volume expansion, preeclampsia , and infant birth weight at high altitude

  17. A nominal set of high-altitude EMP environments

    Energy Technology Data Exchange (ETDEWEB)

    Longmire, C.L.; Hamilton, R.M.; Hahn, J.M.

    1987-02-01

    This report presents high-altitude EMP (HEMP) environments calculated by the CHAP code for a nominal large yield burst at 400 km over the central US. Nominal, unclassified weapon output parameters were used, along with unclassified EMP theory and calculational techniques. While the resulting environments do not represent upper bounds, they should be useful in developing understanding of the effect of HEMP on electrical and electronic systems. The calculated environments illustrate the wide variability of the HEMP from a single burst, depending on ground range and azimuth from ground zero. Analytic fits to the HEMP fields are provided to facilitate coupling calculations. The CHAP results are justified by a detailed examination of Compton currents, air conductivities, and the resulting fields. It is shown that both HEMP theory and the calculations conserve energy scrupulously.

  18. 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.

  19. 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

  20. New Heights with High-Altitude Balloon Launches for Effective Student Learning and Environmental Awareness

    Science.gov (United States)

    Voss, H. D.; Dailey, J. F.; Takehara, D.; Krueger, J. M.

    2009-12-01

    Over a seven-year period Taylor University, an undergraduate liberal art school, has successfully launched and recovered over 200 sophisticated student payloads to altitudes between 20-33 km (100% success with rapid recovery) with flight times between 2 to 6 hrs. All of the payloads included two GPS tracking systems, cameras and monitors, a 110 kbit down link, an uplink command capability for educational experiments (K-12 and undergrad). Launches were conducted during the day and night, with multiple balloons, with up to 10 payloads for experiments, and under varying weather and upper atmospheric conditions. The many launches in a short period of time allowed the payload bus design to evolve toward increased performance, reliability, standardization, simplicity, and modularity for low-cost launch services. Through NSF and NASA grants, the program has expanded leading to over 50 universities trained at workshops to implement high altitude balloon launches in the classroom. A spin-off company (StraoStar Systems LLC) now sells the high-altitude balloon system and facilitates networking between schools. This high-altitude balloon program helps to advance knowledge and understanding across disciplines by giving students and faculty rapid and low-cost access to earth/ecology remote sensing from high altitude, insitu and limb atmospheric measurements, near-space stratosphere measurements, and IR/UV/cosmic ray access to the heavens. This new capability is possible by exposing students to recent advances in MEMS technology, nanotechnology, wireless telecommunication systems, GPS, DSPs and other microchip miniaturizations to build education when they engage in state-of-the-art balloon launch capability into the "unknown" with real-time data (50 Kb) with command interaction. The scientific method comes alive with creativity, problem solving, fun, and multidisciplinary hands-on team work. More students in basic science (and liberal arts) and public have an awareness of the

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

    African Journals Online (AJOL)

    At altitude, the decreasing ambient pressure proportionally decreases available oxygen (hypobaric hypoxia). ... but mild AMS is rapid descent to lower altitudes, which can be facilitated by administration of oxygen and drugs, including acetazolamide, dexamethasone and nifedipine, or use of a portable hyperbaric chamber.

  2. After-effects of a high altitude expedition on blood.

    Science.gov (United States)

    Böning, D; Maassen, N; Jochum, F; Steinacker, J; Halder, A; Thomas, A; Schmidt, W; Noé, G; Kubanek, B

    1997-04-01

    The aim of the study was to investigate blood alterations caused by altitude acclimatization which last more than few days after return and might play a role for exercise performance at sea level. Measurements were performed in 12 mountaineers before, during and either 7/8 or 11/12 days after a Himalaya expedition (26-29 days at 4900 to 7600 m altitude). [Erythropoietin] rose only temporarily at altitude (max. +11 +/- 1 [SE] mu/ml serum). After return hemoglobin mass (initially 881 +/- 44 g, CO-Hb method) was increased by 14% (p training, partly in the Alps, and the stay in the Himalaya influenced O2-affinity for a prolonged time. The adaptations might reduce the loss of physical performance capacity at altitude and be part of altitude training effects.

  3. 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.

  4. Adaptation of an epilithic ecosystem to harsh high altitude environment

    Science.gov (United States)

    de La Torre Noetzel, R.; Horneck, G.; García Sancho, L.; Scherer, K.; Facius, R.; Urlings, T.; Rettberg, P.; Reina, M.; Pintado, A.

    2003-04-01

    Epilithic ecosystems in high mountains are exposed to an extreme microclimate characterized by intense solar UV radiation, high temperature fluctuations and high aridity. Using the epilithic ecosystem Rhizocarpon geographicum, the most abundant lichen at the Plataforma de Gredos (Sierra de Gredos, Central Spain, 1.895 m a.s.l.) as model system, we have investigated whether the cortex protects the photobiont against impacts by this extreme environment. The UV radiation climate was measured optoelectronically as well by use of the biological dosimeter DLR-Biofilm, and the microclimate (temperature, relative humidity, PAR) by a microclimatic station (Squirrel, U.K.). The photosynthetic activity of the lichens was periodically determined by use of a photosynthesis yield analyser MINI PAM. Using lichen samples with- and without cortex during different periods of a growing season, showed a substantial protection by the cortex against environmental stress conditions, especially at summer solstice. Solar UV radiation and desiccation exerted the most damaging effects in lichens without cortex. Because of the high resistance of the intact lichen against the harsh high altitude climate, R. geographicum has been selected as test system for survival studies in space to be performed during the upcoming BIOPAN mission of ESA.

  5. Medical continuing education: reform of teaching methods about high altitude disease in China.

    Science.gov (United States)

    Luo, Yongjun; Zhou, Qiquan; Huang, Jianjun; Luo, Rong; Yang, Xiaohong; Gao, Yuqi

    2013-06-01

    The purpose of high altitude continuing medical education is to adapt knowledge and skills for practical application on the plateau. Most trainees have experience with academic education and grassroots work experience on the plateau, so they want knowledge about new advances in the pathogenesis, diagnosis, and treatment of high altitude disease. As such, traditional classroom teaching methods are not useful to them. Training objects, content, and methods should attempt to conduct a variety of teaching practices. Through continuing medical education on high altitude disease, the authors seek to change the traditional teaching model away from a single classroom and traditional written examinations to expand trainees' abilities. These innovative methods of training can improve both the quality of teaching and students' abilities to prevent and treat acute mountain sickness, high altitude pulmonary edema, high altitude cerebral edema, and chronic mountain sickness to increase the quality of high altitude medical care.

  6. Assessment of hypoxia right heart remodeling after acclimatization at high different altitude areas

    Directory of Open Access Journals (Sweden)

    Xiao-jin LAI

    2012-08-01

    Full Text Available Objective To assess hypoxic right heart remodeling after acclimatization at high altitude area. Methods One hundred volunteers who came to Tibet from the low-altitude areas by plane were randomly selected to serve as control group, and another 100 servicemen, who were dispatched from low altitude area to a station in Tibet area 3000m above sea level and got acclimatized to serve as altitude group. The altitude group was divided into altitude group 1 (3000-4000m above sea level, n=67 and altitude group 2 (4000-5500m above sea level, n=33 according to the altitude of the campsite, and also into migration-time group 1 (entered and stationed in Xizang for 1-2 years, n=72 and migration-time group 2 (entered and stationed in Xizang for over 2 years, n=28. The structure and function of the right heart were measured using a portable multi-functional composite echocardiography in a quiescent state, and hypoxic right heart remodeling after high-altitude acclimatization was comprehensively analyzed and assessed. Results Compared with control group, the main manifestations of the subjects in the altitude group were right ventricular and right atrial enlargement, right ventricular wall thickening, aggravation of tricuspid regurgitation, and broadening of pulmonary trunk and branch (P 4000m above sea level than in those who were in the area 2 years, particularly in those for > 5 years, than those who lived there for < 2 years (P < 0.01. Conclusions The altitude and living time in high-altitude are main factors for hypoxic right heart remodeling. Altitude acclimatization is only the adjustment of human body to hypoxic environment. A portable multi-functional composite echocardiography can early and timely assess hypoxic right heart remodeling and it is of important significance for ensuring the health of the serviceman in high-altitude area.

  7. 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 5000 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...

  8. Control of respiration in flight muscle from the high-altitude bar-headed goose and low-altitude birds.

    Science.gov (United States)

    Scott, Graham R; Richards, Jeffrey G; Milsom, William K

    2009-10-01

    Bar-headed geese fly at altitudes of up to 9,000 m on their biannual migration over the Himalayas. To determine whether the flight muscle of this species has evolved to facilitate exercise at high altitude, we compared the respiratory properties of permeabilized muscle fibers from bar-headed geese and several low-altitude waterfowl species. Respiratory capacities were assessed for maximal ADP stimulation (with single or multiple inputs to the electron transport system) and cytochrome oxidase excess capacity (with an exogenous electron donor) and were generally 20-40% higher in bar-headed geese when creatine was present. When respiration rates were extrapolated to the entire pectoral muscle mass, bar-headed geese had a higher mass-specific aerobic capacity. This may represent a surplus capacity that counteracts the depressive effects of hypoxia on mitochondrial respiration. However, there were no differences in activity for mitochondrial or glycolytic enzymes measured in homogenized muscle. The [ADP] leading to half-maximal stimulation (K(m)) was approximately twofold higher in bar-headed geese (10 vs. 4-6 microM), and, while creatine reduced K(m) by 30% in this species, it had no effect on K(m) in low-altitude birds. Mitochondrial creatine kinase may therefore contribute to the regulation of oxidative phosphorylation in flight muscle of bar-headed geese, which could promote efficient coupling of ATP supply and demand. However, this was not based on differences in creatine kinase activity in isolated mitochondria or homogenized muscle. The unique differences in bar-headed geese existed without prior exercise or hypoxia exposure and were not a result of phylogenetic history, and may, therefore, be important evolutionary specializations for high-altitude flight.

  9. EGLN1 involvement in high-altitude adaptation revealed through genetic analysis of extreme constitution types defined in Ayurveda

    Science.gov (United States)

    Aggarwal, Shilpi; Negi, Sapna; Jha, Pankaj; Singh, Prashant K.; Stobdan, Tsering; Pasha, M. A. Qadar; Ghosh, Saurabh; Agrawal, Anurag; Prasher, Bhavana; Mukerji, Mitali; Brahmachari, S. K.; Majumder, P. P.; Mukerji, M.; Habib, S.; Dash, D.; Ray, K.; Bahl, S.; Singh, L.; Sharma, A.; Roychoudhury, S.; Chandak, G. R.; Thangaraj, K.; Parmar, D.; Sengupta, S.; Bharadwaj, D.; Rath, S. K.; Singh, J.; Jha, G. N.; Virdi, K.; Rao, V. R.; Sinha, S.; Singh, A.; Mitra, A. K.; Mishra, S. K.; Pasha, Q.; Sivasubbu, S.; Pandey, R.; Baral, A.; Singh, P. K.; Sharma, A.; Kumar, J.; Stobdan, T.; Bhasin, Y.; Chauhan, C.; Hussain, A.; Sundaramoorthy, E.; Singh, S. P.; Bandyopadhyay, A.; Dasgupta, K.; Reddy, A. K.; Spurgeon, C. J.; Idris, M. M.; Khanna, V.; Dhawan, A.; Anand, M.; Shankar, R.; Bharti, R. S.; Singh, M.; Singh, A. P.; Khan, A. J.; Shah, P. P.; Pant, A. B.; Kaur, R.; Bisht, K. K.; Kumar, A.; Rajamanickam, V.; Wilson, E.; Thangadurai, A.; Jha, P. K.; Maulik, M.; Makhija, N.; Rahim, A.; Sharma, S.; Chopra, R.; Rana, P.; Chidambaram, M.; Maitra, A.; Chawla, R.; Soni, S.; Khurana, P.; Khan, M. N.; Sutar, S. D.; Tuteja, A.; Narayansamy, K.; Shukla, R.; Prakash, S.; Mahurkar, S.; Mani, K. Radha; Hemavathi, J.; Bhaskar, S.; Khanna, P.; Ramalakshmi, G. S.; Tripathi, S. M.; Thakur, N.; Ghosh, B.; Kukreti, R.; Madan, T.; Verma, R.; Sudheer, G.; Mahajan, A.; Chavali, S.; Tabassum, R.; Grover, S.; Gupta, M.; Batra, J.; Kumar, A.; Nejatizadeh, A.; Vaid, M.; Das, S. K.; Sharma, S.; Sharma, M.; Chatterjee, R.; Paul, J. A.; Srivastava, P.; Rajput, C.; Mittal, U.; Singh, M.; Hariharan, M.; Das, S.; Chaudhuri, K.; Sengupta, M.; Acharya, M.; Bhattacharyya, A.; Saha, A.; Biswas, A.; Chaki, M.; Gupta, A.; Mukherjee, S.; Mookherjee, S.; Chattopadhyay, I.; Banerjee, T.; Chakravorty, M.; Misra, C.; Monadal, G.; Sengupta, S.; Dutta, De. D.; Bajaj, S.; Deb, I.; Banerjee, A.; Chowdhury, R.; Banerjee, D.; Kumar, D.; Das, S. R.; Tiwari, S.; Bharadwaj, A.; Khanna, S.; Ahmed, I.; Parveen, S.; Singh, N.; Dasgupta, D.; Bisht, S. S.; Rajput, R.; Ghosh, B.; Kumar, N.; Chaurasia, A.; Abraham, J. K.; Sinha, A.; Scaria, V.; Sethi, T. P.; Mandal, A. K.; Mukhopadhyay, A.

    2010-01-01

    It is being realized that identification of subgroups within normal controls corresponding to contrasting disease susceptibility is likely to lead to more effective predictive marker discovery. We have previously used the Ayurvedic concept of Prakriti, which relates to phenotypic differences in normal individuals, including response to external environment as well as susceptibility to diseases, to explore molecular differences between three contrasting Prakriti types: Vata, Pitta, and Kapha. EGLN1 was one among 251 differentially expressed genes between the Prakriti types. In the present study, we report a link between high-altitude adaptation and common variations rs479200 (C/T) and rs480902 (T/C) in the EGLN1 gene. Furthermore, the TT genotype of rs479200, which was more frequent in Kapha types and correlated with higher expression of EGLN1, was associated with patients suffering from high-altitude pulmonary edema, whereas it was present at a significantly lower frequency in Pitta and nearly absent in natives of high altitude. Analysis of Human Genome Diversity Panel-Centre d’Etude du Polymorphisme Humain (HGDP-CEPH) and Indian Genome Variation Consortium panels showed that disparate genetic lineages at high altitudes share the same ancestral allele (T) of rs480902 that is overrepresented in Pitta and positively correlated with altitude globally (P < 0.001), including in India. Thus, EGLN1 polymorphisms are associated with high-altitude adaptation, and a genotype rare in highlanders but overrepresented in a subgroup of normal lowlanders discernable by Ayurveda may confer increased risk for high-altitude pulmonary edema. PMID:20956315

  10. Raman spectroscopy of hot desert, high altitude epilithic lichens.

    Science.gov (United States)

    Villar, Susana E Jorge; Edwards, Howell G M; Seaward, Mark R D

    2005-05-01

    Twenty-three highly-coloured lichen specimens belonging to the genera Candelariella, Aspicilia and Xanthoria from high altitude sites in the Atacama Desert, Chile, 2300-4500 metres, have been analysed non-destructively by Raman spectroscopy. The vibrational band assignments in the spectra of the specimens, which were still attached to their limestone or sandstone substrata, were accomplished by comparison with the chemical compositions obtained from wet chemical extraction methods. Carotenoids and chlorophyll were found in all specimens as major components and the characteristic spectral signatures of calcium oxalate monohydrate (whewellite) and dihydrate (weddellite) could be identified; chemical signatures were found for these materials even in lichen thalli growing on the non-calcareous substrata, indicating probably that the calcium was provided here from wind- or rain-borne sources. The Raman spectral biomarkers for a variety of protective biomolecules and accessory pigments such as usnic acid, calycin, pulvinic acid dilactone and rhizocarpic acid have been identified in the lichens, in broad agreement with the chemical extraction profiles. The present study indicates that some form of non-destructive taxonomic identification based on Raman spectroscopy was also possible.

  11. Patent foramen ovale: a novel cardiovascular risk factor in patients with sleep disordered breathing and high altitude dwellers?

    Science.gov (United States)

    Rexhai, Emrush; Scherrer, Urs; Rimoldi, Stefano F

    2016-01-01

    Diseases associated with chronic hypoxaemia are a leading cause of morbidity and mortality in Western countries. Epidemiological data indicate that cardiovascular diseases contribute substantially to this problem, but the underlying mechanisms are incompletely understood. Sleep disordered breathing and high altitude exposure are frequent conditions associated with hypoxaemia. Recent evidence suggests that in these conditions the concomitant presence of a patent foramen ovale plays an important pathogenic role. For example, in patients with obstructive sleep apnoea the presence of a patent foramen ovale is associated with more severe sleep disordered breathing, nocturnal oxygen desaturation, generalised endothelial dysfunction and arterial hypertension. After patent foramen ovale closure, both sleep disordered breathing and cardiovascular phenotype improve, suggesting the existence of a possible causal link. During short-term high altitude exposure, the presence of a patent foramen ovale, by aggravating altitude-induced hypoxaemia, facilitates exaggerated pulmonary hypertension. Interestingly, there is increasing evidence showing that in high-altitude dwellers a patent foramen ovale also alters the cardiovascular phenotype. In this article we will summarise recent evidence demonstrating how a patent foramen ovale alters the cardiovascular phenotype and increases cardiovascular risk in patients with sleep disordered breathing and high-altitude dwellers.

  12. 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.

  13. Regulation of blood volume in lowlanders exposed to high altitude.

    Science.gov (United States)

    Siebenmann, Christoph; Robach, Paul; Lundby, Carsten

    2017-10-01

    Humans ascending to high altitude (HA) experience a reduction in arterial oxyhemoglobin saturation and, as a result, arterial O2 content ([Formula: see text]). As HA exposure extends, this reduction in [Formula: see text] is counteracted by an increase in arterial hemoglobin concentration. Initially, hemoconcentration is exclusively related to a reduction in plasma volume (PV), whereas after several weeks a progressive expansion in total red blood cell volume (RCV) contributes, although often to a modest extent. Since the decrease in PV is more rapid and usually more pronounced than the expansion in RCV, at least during the first weeks of exposure, a reduction in circulating blood volume is common at HA. Although the regulation of hematological responses to HA has been investigated for decades, it remains incompletely understood. This is not only related to the large number of mechanisms that could be involved and the complexity of their interplay but also to the difficulty of conducting comprehensive experiments in the often secluded HA environment. In this review, we present our understanding of the kinetics, the mechanisms and the physiological relevance of the HA-induced reduction in PV and expansion in RCV. Copyright © 2017 the American Physiological Society.

  14. 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.

  15. World, Land, and High-Altitude Saturation Wind Power Potentials

    Science.gov (United States)

    Archer, C. L.; Jacobson, M. Z.

    2012-12-01

    Wind turbines convert kinetic to electrical energy, which returns to the atmosphere as heat to regenerate some potential and kinetic energy. We use the GATOR-GCMOM global model, modified to treat wind turbines as an elevated momentum sink, to explore the effects of increasing the number of wind turbines over large geographic regions. Energy is conserved in the model by converting all electric power generated by the wind turbines to heat via electricity use at the surface, where it occurs, and by converting kinetic energy lost by natural surface roughness to turbulence, then heat. We find that, as the number of turbines is increased, power extraction first increases linearly, but then converges to a "saturation" potential not identified previously from physical principles or turbine properties. These saturation potentials are ~253 TW at 100 m hub height over the entire globe, ~80 TW at 100 m over land and near-shore (outside Antarctica), and ~380 TW at 10 km in the jet streams. Sensitivity to grid resolution is minimal. We propose that these saturation potentials should be used as the world, land, and high-altitude theoretical wind power potentials.

  16. 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.

  17. Coronagraphic Imaging of Exoplanets from a High Altitude Balloon Platform

    Science.gov (United States)

    Unwin, S.

    2012-04-01

    Direct imaging of exoplanets orbiting nearby stars is a major observational challenge, demanding high angular resolution and extremely high dynamic range close to the parent star. Such a system could image and characterize the atmospheres of exoplanets, and also observe exozodiacal dust within the exoplanetary system. The ultimate experiment requires a space-based platform, but demonstrating much of the needed technology as well as performing valuable measurements of circumstellar debris disks, can be done from a high-altitude balloon platform. In this paper, we show how progress in key technologies leads to a balloon experiment as a logical future step toward a space mission. The HCIT testbed has shown ultra-high contrast using small optics in a vacuum testbed. A recent ground-based experiment has demonstrated the ability to control three active optics in series - a lightweight controllable primary mirror, and two deformable mirrors - to achieve close to the best wavefront correction possible with large optics in an in-air testbed. We briefly describe the Wallops Arcsecond Pointer (WASP), which as had a very successful first flight, showing the capability of a balloon platform to stably point to the accuracy required for a coronagraph payload experiment. A balloon-borne coronagraph mission would incorporate all of these advances in an instrument that verifies each one in a space-like environment, and enabling forefront science. Such an experiment would be a step toward mitigating the technical risks of a major space-based exoplanet coronagraph. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. Copyright 2012. California Institute of Technology. Government sponsorship acknowledged.

  18. 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

  19. O+ and H+ ion heat fluxes at high altitudes and high latitudes

    Directory of Open Access Journals (Sweden)

    I. A. Barghouthi

    2014-08-01

    Full Text Available Higher order moments, e.g., perpendicular and parallel heat fluxes, are related to non-Maxwellian plasma distributions. Such distributions are common when the plasma environment is not collision dominated. In the polar wind and auroral regions, the ion outflow is collisionless at altitudes above about 1.2 RE geocentric. In these regions wave–particle interaction is the primary acceleration mechanism of outflowing ionospheric origin ions. We present the altitude profiles of actual and "thermalized" heat fluxes for major ion species in the collisionless region by using the Barghouthi model. By comparing the actual and "thermalized" heat fluxes, we can see whether the heat flux corresponds to a small perturbation of an approximately bi-Maxwellian distribution (actual heat flux is small compared to "thermalized" heat flux, or whether it represents a significant deviation (actual heat flux equal or larger than "thermalized" heat flux. The model takes into account ion heating due to wave–particle interactions as well as the effects of gravity, ambipolar electric field, and divergence of geomagnetic field lines. In the discussion of the ion heat fluxes, we find that (1 the role of the ions located in the energetic tail of the ion velocity distribution function is very significant and has to be taken into consideration when modeling the ion heat flux at high altitudes and high latitudes; (2 at times the parallel and perpendicular heat fluxes have different signs at the same altitude. This indicates that the parallel and perpendicular parts of the ion energy are being transported in opposite directions. This behavior is the result of many competing processes; (3 we identify altitude regions where the actual heat flux is small as compared to the "thermalized" heat flux. In such regions we expect transport equation solutions based on perturbations of bi-Maxwellian distributions to be applicable. This is true for large altitude intervals for protons

  20. Canadian Academy of Sport and Exercise Medicine position statement: athletes at high altitude.

    Science.gov (United States)

    Koehle, Michael S; Cheng, Ivy; Sporer, Benjamin

    2014-03-01

    Many sports incorporate training at altitude as a key component of their athlete training plan. Furthermore, many sports are required to compete at high altitude venues. Exercise at high altitude provides unique challenges to the athlete and to the sport medicine clinician working with these athletes. These challenges include altitude illness, alterations in training intensity and performance, nutritional and hydration difficulties, and challenges related to the austerity of the environment. Furthermore, many of the strategies that are typically utilized by visitors to altitude may have implications from an anti-doping point of view.This position statement was commissioned and approved by the Canadian Academy of Sport and Exercise Medicine. The purpose of this statement was to provide an evidence-based, best practices summary to assist clinicians with the preparation and management of athletes and individuals travelling to altitude for both competition and training.

  1. Why are the high altitude inhabitants like the Tibetans shorter and lighter?

    Science.gov (United States)

    Panesar, N S

    2008-09-01

    High altitude inhabitants (HAI) are generally smaller than low altitude inhabitants (LAI). This anthropological observation has recently been confirmed in the Tibetan refugees who have settled in India since 1950s. Those settled at lower altitudes (970 m) are taller and muscular than compatriots settled at higher altitudes (3500 m). While lower socioeconomic status is implicated in growth retardation at higher altitudes, the smaller stature in adults in well-off communities says otherwise. Hypobaric hypoxia (HH) is the main challenge at high altitudes, which the long established HAI have overcome via biological adaptations, including larger chests, raised blood hemoglobin, and producing more nitric oxide (NO), which deliver similar levels of oxygen to tissues, as LAI. The Tibetans produce 10-fold more NO than LAI. NO is a potent inhibitor of steroidogenesis. Therefore I hypothesize that the short stature and lower musculature in HAI results from steroid deficiency precipitated by NO, which HAI produce to cope with HH.

  2. 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.

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

    NARCIS (Netherlands)

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

    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

  4. High Performance Flexible Thermal Link

    Science.gov (United States)

    Sauer, Arne; Preller, Fabian

    2014-06-01

    The paper deals with the design and performance verification of a high performance and flexible carbon fibre thermal link.Project goal was to design a space qualified thermal link combining low mass, flexibility and high thermal conductivity with new approaches regarding selected materials and processes. The idea was to combine the advantages of existing metallic links regarding flexibility and the thermal performance of high conductive carbon pitch fibres. Special focus is laid on the thermal performance improvement of matrix systems by means of nano-scaled carbon materials in order to improve the thermal performance also perpendicular to the direction of the unidirectional fibres.One of the main challenges was to establish a manufacturing process which allows handling the stiff and brittle fibres, applying the matrix and performing the implementation into an interface component using unconventional process steps like thermal bonding of fibres after metallisation.This research was funded by the German Federal Ministry for Economic Affairs and Energy (BMWi).

  5. 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.

  6. Special problems and capabilities of high altitude lighter than air vehicles

    Science.gov (United States)

    Wessel, P. R.; Petrone, F. J.

    1975-01-01

    Powered LTA vehicles have historically been limited to operations at low altitudes. Conditions exist which may enable a remotely piloted unit to be operated at an altitude near 70,000 feet. Such systems will be launched like high altitude balloons, operate like nonrigid airships, and have mission capabilities comparable to a low altitude stationary satellite. The limited lift available and the stratospheric environment impose special requirements on power systems, hull materials and payloads. Potential nonmilitary uses of the vehicle include communications relay, environmental monitoring and ship traffic control.

  7. 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.

  8. High altitude genetic adaptation in Tibetans: no role of increased hemoglobin-oxygen affinity.

    Science.gov (United States)

    Tashi, Tsewang; Feng, Tang; Koul, Parvaiz; Amaru, Ricardo; Hussey, Dottie; Lorenzo, Felipe R; RiLi, Ge; Prchal, Josef T

    2014-01-01

    High altitude exerts selective evolutionary pressure primarily due to its hypoxic environment, resulting in multiple adaptive responses. High hemoglobin-oxygen affinity is postulated to be one such adaptive change, which has been reported in Sherpas of the Himalayas. Tibetans have lived on the Qinghai-Tibetan plateau for thousands of years and have developed unique phenotypes, such as protection from polycythemia which has been linked to PDH2 mutation, resulting in the downregulation of the HIF pathway. In order to see if Tibetans also developed high hemoglobin-oxygen affinity as a part of their genetic adaptation, we conducted this study assessing hemoglobin-oxygen affinity and their fetal hemoglobin levels in Tibetan subjects from 3 different altitudes. We found normal hemoglobin-oxygen affinity in all subjects, fetal hemoglobin levels were normal in all except one and no hemoglobin variants in any of the subjects. We conclude that increased hemoglobin-oxygen affinity or increased fetal hemoglobin are not adaptive phenotypes of the Tibetan highlanders. Published by Elsevier Inc.

  9. PHYSICAL ADAPTATION OF CHILDREN TO LIFE AT HIGH-ALTITUDE

    NARCIS (Netherlands)

    DEMEER, K; HEYMANS, HSA; ZIJLSTRA, WG

    Children permanently exposed to hypoxia at altitudes of > 3000 m above sea level show a phenotypical form of adaptation. Under these environmental conditions, oxygen uptake in the lungs is enhanced by increases in ventilation, lung compliance, and pulmonary diffusion. Lung and thorax volumes in

  10. 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

  11. Electrocardiographic observations in high altitude residents of Nepal and Bolivia

    Science.gov (United States)

    Raynaud, Jeanne; Valeix, P.; Drouet, L.; Escourrou, P.; Durand, J.

    1981-09-01

    Parameters computed from electrocardiographic recordings (mean frontal QRS axis, â QRS, positive (R-S) difference in lead V1, incidence of atypical conduction pattern in V1) were compared: (1) in two populations residing at the same altitude (3 800 m) but in different geographical sites: Aymaras in Bolivia and Tibetans in Nepal, (2) in three groups of Bolivians dwellers, ethnically similar and fully acclimatized, at three altitudes (4 780 m, 3 800 m, 400 m). This work involved 661 subjects. Results: (a) The mean â QRS value in highlanders is shifted to the right when compared to that of lowlanders: the right axis deviation increases with altitude, (b) The mean â QRS value is identical in Bolivian and Tibetan groups living at the same altitude, (c) The axis deviates to the left with aging in all the environmental conditions. This migration is accompanied by a lower incidence of positive (R-S) difference in adults compared to younger subjects, (d) The mean â QRS value of the females is always situated to the left of that males for all age groups. This difference receives a possible confirmation by the lower incidence of atypical complexes in V1 in females, (e) The present values of â QRS as well as others found in the litterature and those of mean pulmonary arterial pressure reported by different authors have been plotted, both as a function of elevation: The two relationships can be described by two linear functions with a point of intersection. Such points suggest an altitude threshold above which a further decrease in barometric pressure results in marked cardiovascular responses. They are both located in the vicinity of 2 500 m.

  12. A state-of-the-art review and feasibility analysis of high altitude wind power in Northern Ireland

    OpenAIRE

    Lunney, E.; Ban, M.; Duic, N.; Foley, A.

    2017-01-01

    In many countries wind energy has become an indispensable part of the electricity generation mix. The opportunity for ground based wind turbine systems are becoming more and more constrained due to limitations on turbine hub heights, blade lengths and location restrictions linked to environmental and permitting issues including special areas of conservation and social acceptance due to the visual and noise impacts. In the last decade there have been numerous proposals to harness high altitude...

  13. The molecular basis of high-altitude adaptation in deer mice.

    Directory of Open Access Journals (Sweden)

    Jay F Storz

    2007-03-01

    Full Text Available Elucidating genetic mechanisms of adaptation is a goal of central importance in evolutionary biology, yet few empirical studies have succeeded in documenting causal links between molecular variation and organismal fitness in natural populations. Here we report a population genetic analysis of a two-locus alpha-globin polymorphism that underlies physiological adaptation to high-altitude hypoxia in natural populations of deer mice, Peromyscus maniculatus. This system provides a rare opportunity to examine the molecular underpinnings of fitness-related variation in protein function that can be related to a well-defined selection pressure. We surveyed DNA sequence variation in the duplicated alpha-globin genes of P. maniculatus from high- and low-altitude localities (i to identify the specific mutations that may be responsible for the divergent fine-tuning of hemoglobin function and (ii to test whether the genes exhibit the expected signature of diversifying selection between populations that inhabit different elevational zones. Results demonstrate that functionally distinct protein alleles are maintained as a long-term balanced polymorphism and that adaptive modifications of hemoglobin function are produced by the independent or joint effects of five amino acid mutations that modulate oxygen-binding affinity.

  14. 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

  15. 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,

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

    NARCIS (Netherlands)

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

    2012-01-01

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

  17. Women at Altitude: Effects of Menstrual Cycle Phase and Alpha-Adrenergic Blockade on High Altitude Acclimatization.

    Science.gov (United States)

    1996-10-01

    Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington, vA 22202-4302, and to the Office of Management and Budget, Paperwork Reduction...Palmer SK, Dahms TE, et al. Blood volume expansion, preeclampsia , and infant birth weight at high altitude. J Appl Physiol 1993;74:1566- 73. Contract...is Ms. Virginia Miller at DSN 343-7327 or by email at virginia.miller@det.amedd.army.mil. FOR THE COMMANDER: PHYL IM. RINEHART Deputy Chief of, Staff for Information Management

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

    DEFF Research Database (Denmark)

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

    2010-01-01

    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......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...... 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...

  19. High altitude aerodynamic platform concept evaluation and prototype engine testing

    Science.gov (United States)

    Akkerman, J. W.

    1984-01-01

    A design concept has been developed for maintaining a 150-pound payload at 60,000 feet altitude for about 50 hours. A 600-pound liftoff weight aerodynamic vehicle is used which operates at sufficient speeds to withstand prevailing winds. It is powered by a turbocharged four-stoke cycle gasoline fueled engine. Endurance time of 100 hours or more appears to be feasible with hydrogen fuel and a lighter payload. A prototype engine has been tested to 40,000 feet simulated altitude. Mismatch of the engine and the turbocharger system flow and problems with fuel/air mixture ratio control characteristics prohibited operation beyond 40,000 feet. But there seems to be no reason why the concept cannot be developed to function as analytically predicted.

  20. 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

    The tight relation between arterial oxygen content and maximum oxygen uptake (Vv(o2max)within a given person at sea level is diminished with altitude acclimatization. An explanation often suggested for this mismatch is impairment of the muscle O(2) extraction capacity with chronic hypoxia......, and is the focus of the present study. We have studied six lowlanders during maximal exercise at sea level (SL) and with acute (AH) exposure to 4,100 m altitude, and again after 2 (W2) and 8 weeks (W8) of altitude sojourn, where also eight high altitude native (Nat) Aymaras were studied. Fractional arterial muscle...... O(2) extraction at maximal exercise was 90.0+/-1.0% in the Danish lowlanders at sea level, and remained close to this value in all situations. In contrast to this, fractional arterial O(2) extraction was 83.2+/-2.8% in the high altitude natives, and did not change with the induction of normoxia...

  1. Arnold Durig (1872-1961): life and work. An Austrian pioneer in exercise and high altitude physiology.

    Science.gov (United States)

    Burtscher, Martin; Gnaiger, Erich; Burtscher, Johannes; Nachbauer, Werner; Brugger, Andreas

    2012-09-01

    Arnold Durig (1872-1961) grew up in the Austrian mountains in the period when intense exploration of the Alps started. As an enthusiastic mountaineer, scientist, and physician, he became one of the pioneers exploring physiological and pathophysiological aspects of humans sojourning to high altitudes. At the beginning of the 20(th) century, Durig was one of the great physiologists whose knowledge covered the whole field of physiology. Durig founded a renowned School and his students spread all over the world. He stayed in close contact with many colleagues and famous scientists, such as Albert Einstein and Sigmund Freud. Although he was an extremely productive and acknowledged physiologist and teacher at that time, his work and life are not very well known at the beginning of the 3(rd) millennium, even by high altitude physiologists. Thus, this article provides an overview on Durig's life and work, highlighting the most important scientific studies he performed at moderate and high altitudes, in an attempt to provide a few links to the development of high altitude research in the late 19(th) and early 20(th) centuries, complemented by some comments from a current point of view.

  2. 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

  3. The Effect of Mutual Coupling on a High Altitude Platform Diversity System Using Compact Antenna Arrays

    Directory of Open Access Journals (Sweden)

    Tommy Hult

    2010-01-01

    Full Text Available We analyze the destructive effects of mutual coupling and spatial correlation between the separate antenna elements on a combined diversity system consisting of multiple HAPs (High-Altitude Platforms employing various compact MIMO (Multiple-Input Multiple-Output antenna array configurations, in order to enhance the mutual information in HAP communication links. In addition, we assess the influence of the separation angle between HAPs on system performance, and determine the optimal separation angles that maximize the total mutual information of the system for various compact MIMO antennas. Simulation results show that although the mutual information is degraded by mutual coupling and spatial correlation, the proposed HAP diversity system still provides better performance compared to a nondiversity system for all tested scenarios.

  4. Changes in subendocardial viability ratio with acute high-altitude exposure and protective role of acetazolamide.

    Science.gov (United States)

    Salvi, Paolo; Revera, Miriam; Faini, Andrea; Giuliano, Andrea; Gregorini, Francesca; Agostoni, Piergiuseppe; Becerra, Carlos G Ramos; Bilo, Grzegorz; Lombardi, Carolina; O'Rourke, Michael F; Mancia, Giuseppe; Parati, Gianfranco

    2013-04-01

    High-altitude tourism is increasingly frequent, involving also subjects with manifest or subclinical coronary artery disease. Little is known, however, on the effects of altitude exposure on factors affecting coronary perfusion. The aim of our study was to assess myocardial oxygen supply/demand ratio in healthy subjects during acute exposure at high altitude and to evaluate the effect of acetazolamide on this parameter. Forty-four subjects (21 men, age range: 24-59 years) were randomized to double-blind acetazolamide 250 mg bid or placebo. Subendocardial viability ratio and oxygen supply/demand ratio were estimated on carotid artery by means of a validated PulsePen tonometer, at sea level, before and after treatment, and after acute and more prolonged exposure to high altitude (4559 m). On arrival at high altitude, subendocardial viability ratio was reduced in both placebo (from 1.63±0.15 to 1.18±0.17; PSubendocardial viability ratio returned to sea level values (1.65±0.24) after 3 days at high altitude under acetazolamide but remained lower than at sea level under placebo (1.42±0.22; Psubendocardial oxygen supply triggered by exposure to hypobaric hypoxia. Further studies involving also subjects with known or subclinical coronary artery disease are needed to confirm a protective action of acetazolamide on myocardial viability under high-altitude exposure.

  5. Hemosiderin deposition in the brain as footprint of high-altitude cerebral edema.

    Science.gov (United States)

    Schommer, Kai; Kallenberg, Kai; Lutz, Kira; Bärtsch, Peter; Knauth, Michael

    2013-11-12

    Based on recent findings of microhemorrhages (MHs) in the corpus callosum (CC) in 3 individuals after nonfatal high-altitude cerebral edema (HACE), we hypothesized that hemosiderin depositions in the brain after high-altitude exposure are specific for HACE and remain detectable over many years. This was a cross-sectional study involving 37 mountaineers in 4 groups: 10 had experienced HACE, 8 high-altitude pulmonary edema, 11 severe acute mountain sickness, and 8 had climbed to altitudes ≥6,962 m without developing any high-altitude illness. HACE was defined as ataxia necessitating assistance with walking and/or decreased consciousness. Within hemosiderin depositions, which were quantified by a score. Unequivocal MHs located in the splenium of the CC were found in 8 subjects and questionable MHs were found in 2 subjects 1 to 35 months after HACE. They were located outside the CC in 5 more severe cases. MHs remained unchanged in those reexamined after 12 to 50 months. A few unequivocal MHs in the splenium of the CC were found in one subject after severe acute mountain sickness, while one subject with high-altitude pulmonary edema and 2 of the extreme altitude climbers had questionable lesions. In all other subjects, MHs were unequivocally absent. MHs detectable by susceptibility-weighted MRI predominantly in the splenium of the CC are long-lasting footprints of HACE.

  6. HURRICANE AND SEVERE STORM SENTINEL (HS3) HIGH-ALTITUDE IMAGING WIND AND RAIN AIRBORNE PROFILER (HIWRAP) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The Hurricane and Severe Storm Sentinel (HS3) High-Altitude Imaging Wind and Rain dataset was collected from the High-altitude Imaging Wind and Rain Airborne...

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

    Science.gov (United States)

    Schoenmaker, Annelie

    2014-07-01

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

  8. 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......-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...

  9. Flow separation in rocket nozzles under high altitude condition

    Science.gov (United States)

    Stark, R.; Génin, C.

    2017-01-01

    The knowledge of flow separation in rocket nozzles is crucial for rocket engine design and optimum performance. Typically, flow separation is studied under sea-level conditions. However, this disregards the change of the ambient density during ascent of a launcher. The ambient flow properties are an important factor concerning the design of altitude-adaptive rocket nozzles like the dual bell nozzle. For this reason an experimental study was carried out to study the influence of the ambient density on flow separation within conventional nozzles.

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

    DEFF Research Database (Denmark)

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

    1988-01-01

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

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

    Science.gov (United States)

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

    2017-12-01

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

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

    Science.gov (United States)

    Ader, Marilyn; Bergman, Richard N.

    2015-01-01

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

  13. The Threat of High Altitude Electromagnetic Pulses: Why it Should be Keeping Combatant Commanders Up at Night

    Science.gov (United States)

    2009-10-23

    High Altitude Electromagnetic Pulse ( HEMP ) poses a serious and credible threat to U.S. forces. Research and analysis of current HEMP defenses...18 Bibliography 21 iii Abstract High Altitude Electromagnetic Pulse ( HEMP ) poses...detonation. The strongest fields are created when the burst occurs near the earth’s surface, but high altitude detonations are still capable of

  14. 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...

  15. GRIP HIGH ALTITUDE IMAGING WIND AND RAIN AIRBORNE PROFILER (HIWRAP) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The High-Altitude Imaging Wind and Rain Airborne Profiler (HIWRAP) is a dual-frequency (Ka- and Ku-band) conical scan system, configured with a nadir viewing antenna...

  16. GPM Ground Validation High Altitude Imaging Wind and Rain Airborne Profiler (HIWRAP) OLYMPEX V1a

    Data.gov (United States)

    National Aeronautics and Space Administration — The High Altitude Wind and Rain Airborne Profiler (HIWRAP) instrument is a Doppler radar designed to measure tropospheric winds through deriving Doppler profiles...

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

    Science.gov (United States)

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

    2008-09-01

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

  18. 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...

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

    Directory of Open Access Journals (Sweden)

    P. K. Hota

    2015-01-01

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

  20. Analysis of mitochondrial DNA in Tibetan gastric cancer patients at high altitude

    OpenAIRE

    Jiang, Jun; Zhao, Jun-Hui; Wang, Xue-lian; DI, JI; Liu, Zhi-Bo; LI, GUO-YUAN; WANG, MIAO-ZHOU; Li, Yan; Chen, Rong; Ge, Ri-Li

    2015-01-01

    The highest risk areas of gastric cancer are currently Japan, Korea and China; Qinghai, a high-altitude area, has one of the highest gastric cancer rates in China. The incidence of gastric cancer is higher in the Tibetan ethnic group compared to that in the Han ethnic group in Qinghai. This study was conducted to determine the clinical characteristics of mitochondrial DNA (mtDNA) mutations and copy numbers among Tibetans with gastric cancer residing at high altitudes and investigate the assoc...

  1. Magnetospheric Plasma Studies Using Data from the Dynamics Explorer High and Low Altitude Plasma Instruments.

    Science.gov (United States)

    1986-02-01

    State, and ZIP Code) 10 SOURCE OF FUNDING NUMBERS PROGRAM PROJECT TASK WORK UNIT ELEMENT NO NO NO ACCESSION NO 62101F 7661 10 AB 11 TITLE (Include...primary observing platform for the research reported here was Dynamics Explorer 1 (DE-l). The DE-1 High Altitude Plasma Instrument ( HAPI ) consists of...reported here was Dynamics Explorer 1 (DE-l). The DE-1 High Altitude Plasma Instrument ( HAPI ) - consists of five electrostatic analyzers mounted in a fan

  2. Magnetospheric Plasma Studies Using Data from the Dynamics High and Low Altitude Plasma Instruments.

    Science.gov (United States)

    1983-05-15

    Barfield F19628-82-K-0024 9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT. PROJECT, TASK southwest Research Institute AREA & WORK UNIT...the research reported here was Dy- namics Explorer 1 (DE-1). The DE-1 High Altitude Plasma Instrument ( HAPI ) consists of five electrostatic analyzers...OBSERVATIONS OF COUNTERSTREAMING ELECTRONS AT HIGH ALTITUDES Counterstreaminq electrons have been c.Lservicx .), z .e L, r- hlzotde m Instrument ( HAPI

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

    Science.gov (United States)

    2014-05-01

    Naval Health Research Center Syndrome of Acute Anxiety Among Marines After Recent Arrival at High Altitude Michael K. Sracic Darren Thomas...MEDICINE, 179, 5:559, 2014 Syndrome of Acute Anxiety Among Marines After Recent Arrival at High Altitude LT Michael K. Sracic, MC USN*; LT Darren Thomas...Training Center (2,061-3,383 m) for a 30-day exercise. Within the first 6 days of training, 7 servicemen presented with severe, acute anxiety/ panic with

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

    Science.gov (United States)

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

    2010-12-15

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

  5. Effect of High Altitude Exposure on Intraocular Pressure Using Goldmann Applanation Tonometry.

    Science.gov (United States)

    Willmann, Gabriel; Schommer, Kai; Schultheiss, Maximilian; Fischer, M Dominik; Bartz-Schmidt, Karl-Ulrich; Gekeler, Florian; Schatz, Andreas

    2017-06-01

    Willmann, Gabriel, Kai Schommer, Maximilian Schultheiss, M. Dominik Fischer, Karl-Ulrich Bartz-Schmidt, Florian Gekeler, and Andreas Schatz. Effect of high altitude exposure on intraocular pressure using Goldmann applanation tonometry. High Alt Med Biol. 18:114-120, 2017. The aim of the study was to quantify changes of intraocular pressure (IOP) during exposure to 4559 m using the state-of-the-art method of Goldmann applanation tonometry for IOP measurement and to detect correlations between IOP and acute mountain sickness (AMS) in a prospective manner. IOP was measured using a Goldmann applanation tonometer AT 900(®) (Haag-Streit, Switzerland) and central corneal thickness (CCT) with the anterior segment module of a Spectralis™ HRA+OCT(®) device (Heidelberg Engineering, Germany) at baseline and high altitude. Assessment of AMS was performed using the Lake Louise and AMS-C questionnaires, and Pearson's correlation coefficient was calculated for association between IOP and AMS. Raw IOP values at high altitude were not significantly changed compared to baseline. IOP adjusted to the increase in CCT at high altitude, which is known to alter IOP levels, showed a significant reduction for corrected IOP values on day 3 of exposure (morning -2.1 ± 1.2 mmHg; evening -2.3 ± 1.1 mmHg; p high altitude was noted. IOP showed a significant reduction of IOP levels when corrected for increased CCT values at high altitude. Furthermore, the prospective measurement of IOP is not useful in diagnosing AMS or for the prediction of more severe high altitude related illnesses as the decrease in IOP and symptoms of AMS do not correlate during altitude exposure.

  6. Toxicology exposure at high altitude: is it necessary to correct toxic exposure threshold limit values?

    OpenAIRE

    Ramírez, Augusto V.; American College of Occupational and Environmental Medicine

    2013-01-01

    In occupational health to control risk magnitude we apply threshold limit values. Man at high altitude has anatomical-physiological variants in his respiratory system; most important are increases in thoracic capacity, pulmonary ventilation, alveolar/capillary diffusion, and arterial oxygen content. Physiological safe work at high altitude consists in the organism not using extra energy to compensate barometric pressure fall. In respiratory occupational toxicology we must initiate correction ...

  7. 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....

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

    Science.gov (United States)

    Pace, N.

    1973-01-01

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

  9. Adaptation of the Long-Lived Monocarpic Perennial Saxifraga longifolia to High Altitude.

    Science.gov (United States)

    Munné-Bosch, Sergi; Cotado, Alba; Morales, Melanie; Fleta-Soriano, Eva; Villellas, Jesús; Garcia, Maria B

    2016-10-01

    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. © 2016 American Society of Plant Biologists. All Rights Reserved.

  10. Computer generated image of Apex high-altitude research sailplane in flight

    Science.gov (United States)

    1997-01-01

    This computer-generated image depicts the current design concept of the Apex high-altitude research aircraft being developed by Advanced Soaring Concepts (ASC) for NASA's Environmental Research Aircraft and Sensor Technology program, based at NASA's Dryden Flight Research Center, Edwards, California. The Apex High-Altitude Flight Experiment is expected to explore the aerodynamics of controlled flight at very high altitudes near 100,000 feet. The Apex will be hoisted aloft tail-first from Dryden by a large high-altitude balloon and released at about 110,000-feet altitude. As it gradually descends, its instrumentation will collect aerodynamic data. The remotely-piloted, semi-autonomous Apex will combine a modified ASC sailplane fuselage design with a new wing designed at the Massachusetts Institute of Technology. The wing will have a special airfoil designed for high subsonic speeds at extreme altitudes. A device extending behind the right wing is a 'wake rake,' which will measure aerodynamic drag behind a test section of the wing, while a rocket pack mounted beneath the fuselage will assist the Apex in transitioning to horizontal flight. Research flights were expected to begin in mid-1998, but a series of technical problems delayed them. In the spring of 1999, Apex entered mothball status. This continued for a year, and in the spring of 2000 NASA selected Apex as part of phase 1 of the Revolutionary Concepts effort.

  11. High altitude-related hypertensive crisis and acute kidney injury in an asymptomatic healthy individual.

    Science.gov (United States)

    Gilbert-Kawai, Edward; Martin, Daniel; Grocott, Michael; Levett, Denny

    2016-01-01

    High-altitude exposure causes a mild to moderate rise in systolic and diastolic blood pressure. This case report describes the first documented case of a hypertensive crisis at altitude, as well as the first report of the occurrence of acute kidney injury in the context of altitude-related hypertension. A healthy, previously normotensive 30-year old, embarked on a trek to Everest Base Camp (5300 m). During his 11-day ascent the subject developed increasingly worsening hypertension. In the absence of symptoms, the individual initially elected to remain at altitude as had previously been the plan. However, an increase in the severity of his hypertension to a peak of 223/119 mmHg resulted in a decision to descend. On descent he was found to have an acute kidney injury that subsequently resolved spontaneously. His blood pressure reverted to normal at sea level and subsequent investigations including a transthoracic echocardiogram, cardiac magnetic resonance imaging, renal ultrasound, and urinary catecholamines were normal. This report challenges the view that transient rises in blood pressure at altitude are without immediate risk. We review the evidence that altitude induces hypertension and discuss the implications for the management of hypertension at altitude.

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

    Science.gov (United States)

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

    1956-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Martin Buchheit

    2015-03-01

    Full Text Available To compare relative match intensities of sea-level versus high-altitude native soccer players during a 2-week camp at 3600 m, data from 7 sea-level (Australian U17 National team, AUS and 6 high-altitude (a Bolivian U18 team, BOL native soccer players were analysed. Two matches were played at sea-level and three at 3600 m on Days 1, 6 and 13. The Yo-Yo Intermittent recovery test (vYo-YoIR1 was performed at sea-level, and on Days 3 and 10. Match activity profiles were measured via 10-Hz GPS. Distance covered >14.4 km.h-1 (D>14.4 km·h-1 and >80% of vYo-YoIR1 (D>80%vYo-YoIR1 were examined. Upon arrival at altitude, there was a greater decrement in vYo-YoIR1 (Cohen’s d +1.0, 90%CL ± 0.8 and D>14.4 km·h-1 (+0.5 ± 0.8 in AUS. D>14.4 km.h-1 was similarly reduced relative to vYo-YoIR1 in both groups, so that D>80%vYo-YoIR1 remained similarly unchanged (-0.1 ± 0.8. Throughout the altitude sojourn, vYo-YoIR1 and D>14.4 km·h-1 increased in parallel in AUS, so that D>80%vYo-YoIR1 remained stable in AUS (+6.0%/match, 90%CL ± 6.7; conversely D>80%vYo-YoIR1 decreased largely in BOL (-12.2%/match ± 6.2. In sea-level natives competing at high-altitude, changes in match running performance likely follow those in high-intensity running performance. Bolivian data confirm that increases in ‘fitness’ do not necessarily translate into greater match running performance, but rather in reduced relative exercise intensity.

  14. Moderate Altitude Affects High Intensity Running Performance in a Collegiate Women?s Soccer Game

    OpenAIRE

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

    2015-01-01

    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...

  15. 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.

  16. Systemic oxygen extraction during exercise at high altitude

    Science.gov (United States)

    Martin, D. S.; Cobb, A.; Meale, P.; Mitchell, K.; Edsell, M.; Mythen, M. G.; Grocott, M. P. W.; Adams, Tom; Biseker, Lindsay; Booth, Adam; Burdall, Oliver; Cobb, Alexandra; Cumpstey, Andrew; Dauncey, Steve; Edsell, Mark; Farrant, James; Feelisch, Martin; Fernandez, Bernadette; Firth, Oliver; Gilbert, Edward; Grant, Daniel; Grocott, Michael; Hennis, Phil; Jackson, Laura; Jenner, Will; van der Kaaij, Jildou; Khosravi, Maryam; Kortekaas, Edith; Levett, Denny; Mahomed, Zeyn; Martin, Daniel; Meale, Paula; Milledge, Jim; Mitchell, Kay; Mole, Damian; Moses, Oliver; Mythen, Michael; Rigat, Fabio; O'Doherty, Alasdair; Salam, Alex; Sanborn, Matt; Sheperdigian, Adam; Shrubb, Fiona; Simpson, Jo; Talbot, Nick; Wandrag, Liesel; Wijesingha, Savini; Williamson, Wilby; Woolley, Tom; Yow, Heng

    2015-01-01

    Background Classic teaching suggests that diminished availability of oxygen leads to increased tissue oxygen extraction yet evidence to support this notion in the context of hypoxaemia, as opposed to anaemia or cardiac failure, is limited. Methods At 75 m above sea level, and after 7–8 days of acclimatization to 4559 m, systemic oxygen extraction [C(a−v)O2] was calculated in five participants at rest and at peak exercise. Absolute [C(a−v)O2] was calculated by subtracting central venous oxygen content (CcvO2) from arterial oxygen content (CaO2) in blood sampled from central venous and peripheral arterial catheters, respectively. Oxygen uptake (V˙O2) was determined from expired gas analysis during exercise. Results Ascent to altitude resulted in significant hypoxaemia; median (range) SpO2 87.1 (82.5–90.7)% and PaO2 6.6 (5.7–6.8) kPa. While absolute C(a−v)O2 was reduced at maximum exercise at 4559 m [83.9 (67.5–120.9) ml litre−1 vs 99.6 (88.0–151.3) ml litre−1 at 75 m, P=0.043], there was no change in oxygen extraction ratio (OER) [C(a−v)O2/CaO2] between the two altitudes [0.52 (0.48–0.71) at 4559 m and 0.53 (0.49–0.73) at 75 m, P=0.500]. Comparison of C(a−v)O2 at peak V˙O2 at 4559 m and the equivalent V˙O2 at sea level for each participant also revealed no significant difference [83.9 (67.5–120.9) ml litre1 vs 81.2 (73.0–120.7) ml litre−1, respectively, P=0.225]. Conclusion In acclimatized individuals at 4559 m, there was a decline in maximum absolute C(a−v)O2 during exercise but no alteration in OER calculated using central venous oxygen measurements. This suggests that oxygen extraction may have become limited after exposure to 7–8 days of hypoxaemia. PMID:25501722

  17. Systemic oxygen extraction during exercise at high altitude.

    Science.gov (United States)

    Martin, D S; Cobb, A; Meale, P; Mitchell, K; Edsell, M; Mythen, M G; Grocott, M P W

    2015-04-01

    Classic teaching suggests that diminished availability of oxygen leads to increased tissue oxygen extraction yet evidence to support this notion in the context of hypoxaemia, as opposed to anaemia or cardiac failure, is limited. At 75 m above sea level, and after 7-8 days of acclimatization to 4559 m, systemic oxygen extraction [C(a-v)O2] was calculated in five participants at rest and at peak exercise. Absolute [C(a-v)O2] was calculated by subtracting central venous oxygen content (CcvO2) from arterial oxygen content [Formula: see text] in blood sampled from central venous and peripheral arterial catheters, respectively. Oxygen uptake [Formula: see text] was determined from expired gas analysis during exercise. Ascent to altitude resulted in significant hypoxaemia; median (range) [Formula: see text] 87.1 (82.5-90.7)% and [Formula: see text] 6.6 (5.7-6.8) kPa. While absolute C(a-v)O2 was reduced at maximum exercise at 4559 m [83.9 (67.5-120.9) ml litre(-1) vs 99.6 (88.0-151.3) ml litre(-1) at 75 m, P=0.043], there was no change in oxygen extraction ratio (OER) [C(a-v)O2/CaO2] between the two altitudes [0.52 (0.48-0.71) at 4559 m and 0.53 (0.49-0.73) at 75 m, P=0.500]. Comparison of C(a-v)O2 at peak [Formula: see text] at 4559 m and the equivalent [Formula: see text] at sea level for each participant also revealed no significant difference [83.9 (67.5-120.9) ml litre(1) vs 81.2 (73.0-120.7) ml litre(-1), respectively, P=0.225]. In acclimatized individuals at 4559 m, there was a decline in maximum absolute C(a-v)O2 during exercise but no alteration in OER calculated using central venous oxygen measurements. This suggests that oxygen extraction may have become limited after exposure to 7-8 days of hypoxaemia. © The Author 2014. Published by Oxford University Press on behalf of the British Journal of Anaesthesia.

  18. Climate, limiting factors and environmental change in high-altitude forests of Western North America

    Science.gov (United States)

    Peterson, David L.

    The relationships between forest dynamics and climate are predictable for high-altitude forest ecosystems in western North America and other mountainous regions. The duration of snowpack interacts with spring and summer temperature to determine when a snowfree soil surface and sufficiently high soil temperatures for physiological activity occur. Regeneration of tree seedlings varies spatially and temporally as mediated by the duration of the snowpack, which affects the length of the growing season on high-precipitation sites and the soil moisture supply on low-precipitation sites. Regeneration is favoured by climatic conditions that produce a mesic soil moisture regime rather than extremes and by summer temperatures that are sufficiently high to facilitate carbon gain in seedlings. Relatively short-term climatic trends can have major impacts on regeneration patterns, particularly after disturbances. Tree growth in high-snowfall environments (under a marine climate and near the treeline) is generally limited more by precipitation than by temperature, with growth being negatively correlated with snowpack depth. There are many sources of spatial and temporal variation in growth response to climate, most of which are not included in modeling efforts at large spatial scales. Growth response varies between species and within species, depending on subregional climate (high vs. low precipitation in the same mountain range), altitude (treeline vs. lower elevation), aspect (north vs. south) and genotype. The effects of climatic variation on high-altitude forests are distinct from effects in low-altitude ecosystems, and models based on low-altitude forests are not necessarily applicable at higher altitudes. The potential for vegetational inertia—long lag times in response to environmental variation—needs to be considered when evaluating the response of high-altitude forests to climatic change.

  19. Overview of the TILDAE High-Altitude Balloon Mission

    Science.gov (United States)

    Godbole, N. H.; Maruca, B.; Marino, R.; Sundkvist, D. J.; Constantin, S.; Zimmerman, H.; Carbone, V.

    2016-12-01

    Though the presence of intermittent turbulence in the stratosphere has been well established, much remains unknown about it. In situ observations of this phenomenon, which have provided the greatest detail of it, have typically been achieved via sounding balloons (i.e., small balloons which burst at peak altitude) carrying constant-temperature "hot wire" anemometers (CTAs). The Turbulence and Intermittency Long-Duration Atmospheric Experiment (TILDAE) was developed to test a new paradigm for stratospheric observations. Rather than flying on a sounding balloon, TILDAE was incorporated as an "add-on" experiment to the payload of a NASA long-duration balloon mission that launched in January, 2016 from McMurdo Station, Antarctica. Furthermore, TILDAE's key instrument was a sonic anemometer, which (relative to a CTA) provides better-calibrated measurements of wind velocity and more-robust separation of velocity components. This presentation focuses on the technical details of TILDAE's instrumentation and the performance thereof during its flight. Potential design improvements for future flights are also discussed.

  20. Characterization of high-altitude winds from infrasound observations

    Science.gov (United States)

    Lalande, J.; Le Pichon, A.; Blanc, E.; Assink, J. D.; Waxler, R.; Blanc-Benon, P.; Sèbe, O.; Landes, M.

    2012-12-01

    Infrasonic waves in the frequency band 0.01-4 Hz are continuously recorded by the International Monitoring System (IMS) designed for the verification of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). These waves propagate at long-ranges through atmospheric ducts resulting from the natural stratification of atmospheric properties (temperature, density, winds, ...) and represent a valuable information to understand atmospheric dynamic until the lower thermosphere. Our research focuses on determining the potential of infrasound observations to improve atmospheric specifications. We develop an inverse algorithm in order to estimate atmospheric parameters from infrasonic observations. The forward problem is handled by a ray-tracing algorithm. First-order perturbation equation resulting from perturbation of atmospheric properties, and especially wind parameters, are developped and numerically validated. We then analyse the inverse problem through several numerical experiments in order to show the capabilities and limitations of our algorithm. Results show the suitability of our approach and indicate that infrasonic observations can significantly improve current atmospheric specification at the altitudes of acoustic energy refraction, i.e. around 50 km and between 100 and 120 km. Performances and limitations of infrasound atmospheric sounding methods are finally discussed in details.

  1. High altitude exposure impairs sleep patterns, mood, and cognitive functions.

    Science.gov (United States)

    de Aquino Lemos, Valdir; Antunes, Hanna Karen Moreira; dos Santos, Ronaldo Vagner Thomatieli; Lira, Fabio Santos; Tufik, Sergio; de Mello, Marco Túlio

    2012-09-01

    This work evaluated the importance of sleep on mood and cognition after 24 h of exposure to hypoxia. Ten males, aged 23-30 years, were placed in a normobaric chamber simulating an altitude of 4,500 m. Sleep assessments were conducted from 22:00-6:00; all mood and cognitive assessments were performed 20 min after awakening. The assessments were conducted in normoxic conditions and after 24 h of hypoxia. Sleep was reevaluated 14 h after the start of exposure to hypoxic conditions, and mood state and cognitive functions were reevaluated 24 h after the start of exposure to hypoxic conditions. Hypoxia reduced total sleep time, sleep efficiency, slow-wave sleep, and rapid eye movement. Depressive mood, anger, and fatigue increased under hypoxic conditions. Vigor, attention, visual and working memory, concentration, executive functions, inhibitory control, and speed of mental processing worsened. Changes in sleep patterns can modulate mood and cognition after 24 h. Copyright © 2012 Society for Psychophysiological Research.

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

    Directory of Open Access Journals (Sweden)

    Ming-ke JIAO

    2017-02-01

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

  3. "Omics" of High Altitude Biology: A Urinary Metabolomics Biomarker Study of Rats Under Hypobaric Hypoxia.

    Science.gov (United States)

    Koundal, Sunil; Gandhi, Sonia; Kaur, Tanzeer; Mazumder, Avik; Khushu, Subash

    2015-12-01

    High altitude medicine is an emerging subspecialty that has crosscutting relevance for 21(st) century science and society: from sports medicine and aerospace industry to urban and rural communities living in high altitude. Recreational travel to high altitude has also become increasingly popular. Rarely has the biology of high altitude biology been studied using systems sciences and omics high-throughput technologies. In the present study, 1H-NMR-based metabolomics, along with multivariate analyses, were employed in a preclinical rat model to characterize the urinary metabolome under hypobaric hypoxia stress. Rats were exposed to simulated altitude of 6700 m above the sea level. The urine samples were collected from pre- and post-exposure (1, 3, 7, and 14 days) of hypobaric hypoxia. Metabolomics urinalysis showed alterations in TCA cycle metabolites (citrate, α-ketoglutarate), cell membrane metabolism (choline), gut micro-flora metabolism (hippurate, phenylacetylglycine), and others (N-acetyl glutamate, creatine, taurine) in response to hypobaric hypoxia. Taurine, a potential biomarker of hepatic function, was elevated after 3 days of hypobaric hypoxia, which indicates altered liver functioning. Liver histopathology confirmed the damage to tissue architecture due to hypobaric hypoxia. The metabolic pathway analysis identified taurine metabolism and TCA as important pathways that might have contributed to hypobaric hypoxia-induced pathophysiology. This study demonstrates the use of metabolomics as a promising tool for discovery and understanding of novel biochemical responses to hypobaric hypoxia exposure, providing new insight in the field of high altitude medicine and the attendant health problems that occur in response to high altitude. The findings reported here also have potential relevance for sports medicine and aviation sciences.

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

    Science.gov (United States)

    Ivy, Catherine M; Scott, Graham R

    2015-08-01

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

  5. A half century of high-altitude studies in anthropology: introduction to the plenary session.

    Science.gov (United States)

    Little, Michael A; Thomas, R Brooke; Garruto, Ralph M

    2013-01-01

    Until 50 years ago, high-altitude terrestrial research was conducted largely within the realm of environmental physiology, where interests were focused on physiological mechanisms and mountain exploration. Scientists from the United States, Europe, and Peru had developed sophisticated physiological models of adaptation and acclimatization to the hypoxia of high altitude, but very little research had been conducted on permanent residents, particularly natives of high altitude in the two major regions of the world-the Andes and the Himalayas. In 1962, Raul T. Baker initiated a project at the Pennsylvania State University to explore the responses of indigenous Peruvians to the major stresses at altitude: hypoxia and cold. Approaches to this early research were anthropological in perspective and centered on population-level studies with an evolutionary approach. Studies were conducted by applying a combination of physiological experimental methods, simulated field experiments, and extended anthropological field observations. Early hypotheses at this time were that heredity played a major role in the adaptive complexes in native high-altitude residents. These early hypotheses were later modified to incorporate or replace the genetic hypotheses with developmental adaptation models. A half century of research within anthropology and research in other fields has presented a vastly more complex and integrated picture of high-altitude adaptation in native residents. Recent studies incorporate physiology and oxygen transport, population and molecular genetics, reproduction, growth, and development. The history and current status of high-altitude research and its anthropological applications are treated in papers from this plenary symposium. Copyright © 2013 Wiley Periodicals, Inc.

  6. Elevated performance: the unique physiology of birds that fly at high altitudes.

    Science.gov (United States)

    Scott, Graham R

    2011-08-01

    Birds that fly at high altitudes must support vigorous exercise in oxygen-thin environments. Here I discuss the characteristics that help high fliers sustain the high rates of metabolism needed for flight at elevation. Many traits in the O(2) transport pathway distinguish birds in general from other vertebrates. These include enhanced gas-exchange efficiency in the lungs, maintenance of O(2) delivery and oxygenation in the brain during hypoxia, augmented O(2) diffusion capacity in peripheral tissues and a high aerobic capacity. These traits are not high-altitude adaptations, because they are also characteristic of lowland birds, but are nonetheless important for hypoxia tolerance and exercise capacity. However, unique specializations also appear to have arisen, presumably by high-altitude adaptation, at every step in the O(2) pathway of highland species. The distinctive features of high fliers include an enhanced hypoxic ventilatory response, an effective breathing pattern, larger lungs, haemoglobin with a higher O(2) affinity, further augmentation of O(2) diffusion capacity in the periphery and multiple alterations in the metabolic properties of cardiac and skeletal muscle. These unique specializations improve the uptake, circulation and efficient utilization of O(2) during high-altitude hypoxia. High-altitude birds also have larger wings than their lowland relatives to reduce the metabolic costs of staying aloft in low-density air. High fliers are therefore unique in many ways, but the relative roles of adaptation and plasticity (acclimatization) in high-altitude flight are still unclear. Disentangling these roles will be instrumental if we are to understand the physiological basis of altitudinal range limits and how they might shift in response to climate change.

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

    Science.gov (United States)

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

    2017-11-02

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

  8. Structural and functional changes of the human macula during acute exposure to high altitude.

    Directory of Open Access Journals (Sweden)

    M Dominik Fischer

    Full Text Available BACKGROUND: This study aimed to quantify structural and functional changes at the macula during acute exposure to high altitude and to assess their structure/function relationship. This work is related to the Tuebingen High Altitude Ophthalmology (THAO study. METHODOLOGY/PRINCIPAL FINDINGS: Spectral domain optical coherence tomography and microperimetry were used to quantify changes of central retinal structure and function in 14 healthy subjects during acute exposure to high altitude (4559 m. High-resolution volume scans and fundus-controlled microperimetry of the posterior pole were performed in addition to best-corrected visual acuity (BCVA measurements and assessment of acute mountain sickness. Analysis of measurements at altitude vs. baseline revealed increased total retinal thickness (TRT in all four outer ETDRS grid subfields during acute altitude exposure (TRT(outer = 2.80 ± 1.00 μm; mean change ± 95%CI. This change was inverted towards the inner four subfields (TRT(inner = -1.89 ± 0.97 μm with significant reduction of TRT in the fovea (TRT(foveal = -6.62 ± 0.90 μm at altitude. BCVA revealed no significant difference compared to baseline (0.06 ± 0.08 logMAR. Microperimetry showed stable mean sensitivity in all but the foveal subfield (MS(foveal = -1.12 ± 0.68 dB. At baseline recordings before and >2 weeks after high altitude exposure, all subjects showed equal levels with no sign of persisting structural or functional sequels. CONCLUSIONS/SIGNIFICANCE: During acute exposure to high altitude central retinal thickness is subject to minor, yet statistically significant changes. These alterations describe a function of eccentricity with an increase in regions with relatively higher retinal nerve fiber content and vascular arcades. However, these changes did not correlate with measures of central retinal function or acute mountain sickness. For the first time a quantitative approach has been used to assess these changes during acute

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

    Science.gov (United States)

    Despland, Emma

    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 5000 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.

  10. 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.

  11. Effect of short-term acclimatization to high altitude on sleep and nocturnal breathing.

    Science.gov (United States)

    Nussbaumer-Ochsner, Yvonne; Ursprung, Justyna; Siebenmann, Christoph; Maggiorini, Marco; Bloch, Konrad E

    2012-03-01

    Objective physiologic data on sleep and nocturnal breathing at initial exposure and during acclimatization to high altitude are scant. We tested the hypothesis that acute exposure to high altitude induces quantitative and qualitative changes in sleep and that these changes are partially reversed with acclimatization. Prospective observation. One night in a sleep laboratory at 490 meters, the first and the third night in a mountain hut at 4559 meters. Sixteen healthy mountaineers. Altitude exposure. Polysomnography, questionnaire evaluation of sleep and acute mountain sickness. Compared to 490 m, median nocturnal oxygen saturation decreased during the 1st night at 4559 m from 96% to 67%, minute ventilation increased from 4.4 to 6.3 L/min, and the apnea-hypopnea index increased from 0.1 to 60.9/h; correspondingly, sleep efficiency decreased from 93% to 69%, and slow wave sleep from 18% to 6% (P sleep 11% (P sleep were significantly reduced in the morning after the 3rd vs. the 1st night at 4559 m. In healthy mountaineers ascending rapidly to high altitude, sleep quality is initially impaired but improves with acclimatization in association with improved oxygen saturation, while periodic breathing persists. Therefore, high altitude sleep disturbances seem to be related predominantly to hypoxemia rather than to periodic breathing.

  12. Daniel Vergara Lope and Carlos Monge Medrano: two pioneers of high altitude medicine.

    Science.gov (United States)

    Rodríguez de Romo, Ana Cecilia

    2002-01-01

    Daniel Vergara Lope from Mexico and Carlos Monge Medrano from Peru were brilliant scientists in their own countries. Both scientists studied high altitude physiology and defined the physiological and anatomical mechanisms of adaptation to high elevations. The Mexican physiologist proposed his ideas 40 years before his Peruvian counterpart. This paper studies the contribution of Vergara Lope and Monge Medrano to the understanding of high altitude medicine and proposes explanations of why history has given priority to Monge, whereas Vergara Lope is relegated to anonymity.

  13. 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...

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

    DEFF Research Database (Denmark)

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

    2003-01-01

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

  15. Analysis of high altitude clouds in the martian atmosphere based on Mars Climate Sounder observations

    Science.gov (United States)

    Puspitarini, L.; Määttänen, A.; Fouchet, T.; Kleinboehl, A.; Kass, D. M.; Schofield, J. T.

    2016-11-01

    High altitude clouds have been observed in the Martian atmosphere. However, their properties still remain to be characterized. Mars Climate Sounder (MCS) aboard Mars Reconnaissance Orbiter (MRO) is an instrument that measures radiances in the thermal infrared, both in limb and nadir views. It allows us to retrieve vertical profiles of radiance, temperature and aerosols. Using the MCS data and radiative transfer model coupled with an automated inversion routine, we can investigate the chemical composition of the high altitude clouds. We will present the first results on the properties of the clouds. CO2 ice is the best candidate to be the main component of some high altitude clouds due to the most similar spectral variation compared to water ice or dust, in agreement with previous studies. Using cloud composition of contaminated CO2 ice (dust core surrounded by CO2 ice) might improve the fitting result, but further study is needed.

  16. Respiratory mechanics of eleven avian species resident at high and low altitude.

    Science.gov (United States)

    York, Julia M; Chua, Beverly A; Ivy, Catherine M; Alza, Luis; Cheek, Rebecca; Scott, Graham R; McCracken, Kevin G; Frappell, Peter B; Dawson, Neal J; Laguë, Sabine L; Milsom, William K

    2017-03-15

    The metabolic cost of breathing at rest has never been successfully measured in birds, but has been hypothesized to be higher than in mammals of a similar size because of the rocking motion of the avian sternum being encumbered by the pectoral flight muscles. To measure the cost and work of breathing, and to investigate whether species resident at high altitude exhibit morphological or mechanical changes that alter the work of breathing, we studied 11 species of waterfowl: five from high altitudes (>3000 m) in Perú, and six from low altitudes in Oregon, USA. Birds were anesthetized and mechanically ventilated in sternal recumbency with known tidal volumes and breathing frequencies. The work done by the ventilator was measured, and these values were applied to the combinations of tidal volumes and breathing frequencies used by the birds to breathe at rest. We found the respiratory system of high-altitude species to be of a similar size, but consistently more compliant than that of low-altitude sister taxa, although this did not translate to a significantly reduced work of breathing. The metabolic cost of breathing was estimated to be between 1 and 3% of basal metabolic rate, as low or lower than estimates for other groups of tetrapods. © 2017. Published by The Company of Biologists Ltd.

  17. 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. Copyright © 2015 the American Physiological Society.

  18. 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%

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

    Science.gov (United States)

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

    1972-01-01

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

  20. 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.

  1. 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.

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

    Science.gov (United States)

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

  3. The use of skeletal muscle near infrared spectroscopy and a vascular occlusion test at high altitude

    NARCIS (Netherlands)

    Martin, Daniel S.; Levett, Denny Z. H.; Bezemer, Rick; Montgomery, Hugh E.; Grocott, Mike P. W.

    2013-01-01

    Abstract Martin, Daniel, Denny Levett, Rick Bezemer, Hugh Montgomery, and Mike Grocott. The use of skeletal muscle near infrared spectroscopy and a vascular occlusion test at high altitude. High Alt Med Biol 14:256-262, 2013.-Microcirculatory function, central to tissue regulation of oxygen flux,

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

    NARCIS (Netherlands)

    Shea, J. M.; Wagnon, P.; Immerzeel, W. W.|info:eu-repo/dai/nl/290472113; 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

  5. De-adaptation change in cardiac function of laborers engaged in physical labor at high altitude after returning to lower altitude

    Directory of Open Access Journals (Sweden)

    En-zhi FENG

    2012-09-01

    Full Text Available Objective To assess the effects of physical labor on cardiac function of laborers at high altitude and changes in cardiac function after returning to lower altitude. Methods According to symptomatic scores on Chinese acute high altitude reaction (AHAR, 96 male officers and soldiers, who rapidly entered high altitude areas (3700m altitude,and engaged in heavy physical work for 50 days, were be scored and graded. Levels of creatine kinase isoenzymes -MB (CK-MB and lactic dehydrogenase isoenzyme -1 (LDH-1 in the serum, Tei index, left ventricular ejection fraction (LVEF, and left ventricular fractional shortening (LVFS were measured in the 96 servicemen at the 50th day of residing at high altitude, and the 2nd and 15th day after returning to lower altitude (1500m altitude, and the results were compared with that of 50 healthy controls residing at 1500m. Results  Among the 96 male servicemen, 71 developed AHAR, and 24 of them had severe AHAR, 47 mild to moderate AHAR, and the rest 25 had no AHAR. Levels of serum CK-MB, LDH-1 and Tei index were higher in the severe AHAR group than in the mild to moderate AHAR group, higher in the mild to moderate AHAR group than in the no AHAR group and higher in the no AHAR group than in the healthy group. As far as the values of LVEF and LVFS were concerned, the severe AHAR group < mild to moderate AHAR group < no AHAR group < control group. Significant difference was found in these levels between every two successive groups (P < 0.01. Linear correlation analysis showed that levels of CK-MB and LDH-1 of persons staying at 3700m altitude for 50 days were positively correlated with Tei index (r= 0.625, 0.598, respectively, P<0.01, and negatively correlated with LVEF(r=-0.716, -0.658, respectively, P<0.01, and also negatively correlated with LVFS (r=-0.639, -0.727, respectively, P<0.01. Level of serum CK-MB, LDH-1 and Tei index at 3700m altitude for 50 days were significantly higher than those 2

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

    Science.gov (United States)

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

    2013-02-01

    The Air Quality Standards for Particulate Matter (PM) at high altitude urban areas in different countries, must consider the pressure and temperature due to the effect that these parameters have on the breath volume. This paper shows the importance to correct Air Quality Standards for PM considering pressure and temperature at different altitudes. Specific factors were suggested to convert the information concerning PM, from local to standard conditions, and adjust the Air Quality Standards for different high altitudes cities. The correction factors ranged from: 1.03 for Santiago de Chile to 1.47 for El Alto Bolivia. Other cities in this study include: Mexico City, México; La Paz, Bolivia; Bogota, Cali and Medellin, Colombia; Quito, Ecuador and Cuzco, Peru. If these corrections are not considered, the atmospheric concentrations will be underestimated. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Gravity Wave-induced High-altitude CO2 Ice Clouds in Mars' Atmosphere

    Science.gov (United States)

    Yigit, E.; Medvedev, A. S.; Hartogh, P.

    2015-12-01

    First general circulation model simulations that quantify and reproduce patches of cold air required for CO2 condensation and ice cloud formation in Mars' atmosphere are presented. Results suggest that these ice clouds are generated by lower atmospheric small-scale gravity waves (GWs) accounted for in the model with the interactively implemented spectral GW parameterization of Yiğit et al. (2008). Distributions of GW-induced temperature fluctuations and occurrences of supersaturation conditions are in a good qualitative agreement with observations of high-altitude CO2 ice clouds. Our study confirms the key role of subgrid-scale GWs in facilitating high-altitude CO2 cloud formation and predicts clouds at altitudes higher than have been observed to date.

  8. Effects of antioxidant vitamins on newborn and placental traits in gestations at high altitude: comparative study in high and low altitude native sheep.

    Science.gov (United States)

    Parraguez, Víctor H; Atlagich, Miljenko; Araneda, Oscar; García, Carlos; Muñoz, Andrés; De Los Reyes, Mónica; Urquieta, Bessie

    2011-01-01

    The present study evaluated the hypothesis that the effects of hypoxia on sheep pregnancies at high altitude (HA) are mediated by oxidative stress and that antioxidant vitamins may prevent these effects. Both HA native and newcomer ewes were maintained at an altitude of 3,589 m during mating and pregnancy. Control low altitude (LA) native ewes were maintained at sea level. Half of each group received daily oral supplements of vitamins C (500 mg) and E (350 IU) during mating and gestation. Near term, maternal plasma vitamin levels and oxidative stress biomarkers were measured. At delivery, lambs were weighed and measured, and placentas were recovered for macroscopic and microscopic evaluation. Vitamin concentrations in supplemented ewes were two- or threefold greater than in non-supplemented ewes. Plasma carbonyls and malondialdehyde in non-supplemented ewes were consistent with a state of oxidative stress, which was prevented by vitamin supplementation. Vitamin supplementation increased lamb birthweight and cotyledon number in both HA native and newcomer ewes, although placental weight and cotyledon surface were diminished. Placentas from vitamin-supplemented HA ewes were similar to those from ewes at sea level, making these placental traits (weight, number and diameter of cotyledons) similar to those from ewes at sea level. Vitamin supplementation had no effect on LA pregnancies. In conclusion, supplementation with vitamins C and E during pregnancy at HA prevents oxidative stress, improving pregnancy outcomes.

  9. High-Altitude Laser Altimetry from the Global Hawk UAV for Regional Mapping of Surface Topography

    Science.gov (United States)

    Blair, J. B.; Rabine, D.; Wake, S.; Hofton, M. A.; Michell, S.

    2012-12-01

    NASA's Land, Vegetation, and Ice Sensor (LVIS) is a high-altitude, full-waveform, geodetic-imaging laser altimeter system of which a UAV-based version (LVIS-GH) is currently being tested. From 20 km above the surface in the Global Hawk UAV, LVIS-GH images surface topography and roughness (including forest height) across a 4 km wide swath using 15 m diameter footprints. In recent years, the LVIS has been flown at altitudes of up to 14 km over Greenland and Antarctica on flights up to 12 hours in duration, enabling the efficient and precise mapping of large areas from the air. The Global Hawk will extend this capability to up to 32 hours and altitudes approaching 20 km. In order to achieve decimeter level vertical precision and accuracy from high altitude, advanced parameter estimation techniques, based on those implemented in NASA's GEODYN software, are used to estimate the angular, spatial, and temporal biases required to accurately georeference the component lidar data sets. Data from specific in-air maneuvers are utilized in order to isolate the effects of different error sources and to break correlations between biases. Examples of high-altitude data and airborne/spaceborne sensor intercomparison and fusion will be shown. For example, the comparison of data from NASA's ICESat-1 mission with coincident LVIS data collected around 86S (the maximum extent of data collected during ICESat) to quantify inter-campaign biases in Icesat-1 elevation measurements and improve estimates of long -term elevation change rates of ice sheets will be shown. These results illustrate the utility of high-altitude wide swath imaging, particularly from platforms such as the Global-Hawk, for enhancing spacebased data sets.

  10. [Adaptive mechanisms and behavioural recommendations: playing football in heat, cold and high altitude conditions].

    Science.gov (United States)

    Born, D-P; Hoppe, M W; Lindner, N; Freiwald, J; Holmberg, H-C; Sperlich, B

    2014-03-01

    Football is played worldwide and players often have to cope with hot and cold temperatures as well as high altitude conditions. The upcoming and past world championships in Brazil, Qatar and South Africa illustrate the necessity for behavioural strategies and adaptation to extreme environmental conditions. When playing football in the heat or cold, special clothing, hydration and nutritional and acclimatisation strategies are vital for high-level performance. When playing at high altitude, the reduced oxygen partial pressure impairs endurance performance and alters the technical and tactical requirements. Special high-altitude adaptation and preparation strategies are essential for football teams based at sea-level in order to perform well and compete successfully. Therefore, the aim of the underlying review is: 1) to highlight the difficulties and needs of football teams competing in extreme environmental conditions, 2) to summarise the thermoregulatory, physiological, neuronal and psychological mechanism, and 3) to provide recommendations for coping with extreme environmental conditions in order to perform at a high level when playing football in the heat, cold and at high altitude. © Georg Thieme Verlag KG Stuttgart · New York.

  11. Pollen, mite and mould samplings by a personal collector at high altitude in Nepal.

    Science.gov (United States)

    Fiorina, A; Legnani, D; Fasano, V; Cogo, A; Basnyat, B; Passalacqua, G; Scordamaglia, A

    1998-01-01

    The new personal portable sampler for detection of environmental biologic particles (Partrap FA52, Coppa, Biella, Italy) was used to evaluate both atmospheric and indoor biologic particles in bedding at high altitudes during two Italian scientific expeditions in Nepal, in 1994 and 1996 respectively. The sampling was performed outdoors and indoors at the following altitudes: Katmandu 1,330 meters (m), LuKla 2,800 m, Namche 3,500 m, Pericle 4,200 m and Piramide 5,050 m. In both expeditions each sample of outdoor and indoor air was obtained by sucking air into the sampler either against the wind during a 6-h period, from 9 am to 3 pm, or from bedding of inhabitants resident at the different altitudes for 5 min. The number of pollens, moulds and mites trapped in each sample were assessed. The statistical analysis of the results by Spearman correlation test revealed a significant inverse correlation (p < 0.02) between altitude and the number of the considered biologic particles for sampling carried out during both the 1994 and 1996 expeditions. Moreover, Wilcoxon paired test showed no significant difference between the biologic sampling obtained in the two expeditions. These results confirm the decrease of the environmental biologic charge in relation to the increase of altitude and prove the efficacy of Partrap FA52 in obtaining reproducible quantitative data.

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

    Indian Academy of Sciences (India)

    The second group, including Gloeocapsopsis pleurocapsoides, Leptolyngbya antarctica, L. frigida, Pseudanabaena frigida and N. spongiaeforme, occurred in oligotrophic water with high pH and low temperature. The distribution of third group of Cyanobium parvum, Synechocystis pevalekii, L. benthonica, L. foveolarum, ...

  13. Effectiveness of Preacclimatization Strategies for High-Altitude Exposure

    Science.gov (United States)

    2013-01-01

    weakness, and insomnia of varying severities and are affected by factors such as ascent rate, elevation obtained, intensity of physical exertion, hydration ...combination for subsequent exposure to high alti- tude is yet to be determined (17,18). The Question A question of particular relevance to athletes

  14. Evaluation of promising sweetpotato genotypes for high altitude ...

    African Journals Online (AJOL)

    about Alternaria disease and breeding for resistance has been reported by several authors. Ted Carey 1997 quating. Janseen 1982 and Ndamage et al 1992 reported that two high yielding varieties with good taste and resistance to. SPVD and Alternaria blight were identified and disseminated by the Rwanda Sweetpotato ...

  15. A new technique for low-to-high altitude predictions of ablative hypersonic flowfields

    Science.gov (United States)

    Bhutta, Bilal A.; Lewis, Clark H.

    1991-01-01

    A parabolized Navier-Stokes (PNS) technique for predicting chemically reacting reentry flows over a wide range of altitudes extending from zero to 259 kft is presented. This coupled-chemistry PNS scheme can use either a strongly implicit solution approach or a two-step solution approach and is used to study a hypersonic flow over various configurations over a Mach-number range of 6.89 to 20. It is demonstrated that the two-step solution provides a combination of accuracy, stability, and computational efficiency. Nonablating low-altitude calculations show that the flowfield is in chemical equilibrium only in the near-wall region, while finite-rate chemistry effects are significant over a major portion of the shock layer, and the Blottner-type linearization of the production terms is unstable for low-altitude high-Reynolds-number conditions.

  16. Thermal comfort and clothing insulation of resting tent occupants at high altitude.

    Science.gov (United States)

    Cena, Krzysztof; Davey, Nicole; Erlandson, Tamara

    2003-11-01

    Thirty-nine males and 18 females, in six groups, participated in six high altitude treks (each lasting 3-4 weeks and climbing up to 5500m) in the Himalaya and Karakoram. Inverse relationships between mean overnight total insulation (sleeping bag plus clothing) and air temperature in tents were recorded for all treks. Average overnight thermal sensations varied little with air temperature as the subjects modified their clothing insulation to maintain thermal sensations warmer than 'neutral' for all treks. For combined treks, subjects adjusted their mean overnight total insulation up to 7clo for thermal sensations of between 0 ('neutral') and +1 ('slightly warm') on average, measured on the standard seven-point thermal sensation scale developed for everyday low-altitude conditions. Very few subjects (3% of all daily responses, on average) reported 'cool' or 'cold' sensations. General tent discomfort increased with altitude suggesting that subjects interpreted tent comfort predominantly in terms of thermal outdoor conditions.

  17. Holocene paleolimnological reconstruction of a high altitude Colombian tropical lake

    OpenAIRE

    Cardozo, A. Y. V.; Gomes, D. F.; da Silva, E. M.; Duque, S. R. E.; Rangel, J. O. C.; Sifeddine, Abdelfettah; Turcq, Bruno; Albuquerque, A. L. S.

    2014-01-01

    Aquatic environments in the high-Andean may be quite vulnerable to climatic conditions and hydrological processes (precipitation/evaporation) that have the potential to alter water levels and chemistry. This study reconstructs the paleohydrological history of Lake Tota, Colombia, to provide a record of environmental changes in the eastern flank of the Colombian Andes during the late Holocene. A 54 cm core was collected at the margin of the lake at a depth of 1.5 m, and the paleohydrological r...

  18. System for beaming power from earth to a high altitude platform

    Science.gov (United States)

    Friedman, Herbert W.; Porter, Terry J.

    2002-01-01

    Power is transmitted to a high altitude platform by an array of diode pumped solid state lasers each operated at a single range of laser wavelengths outside of infrared and without using adaptive optics. Each laser produces a beam with a desired arrival spot size. An aircraft avoidance system uses a radar system for automatic control of the shutters of the lasers.

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

    Science.gov (United States)

    Xing, Jinchuan; Wuren, Tana; Simonson, Tatum S; Watkins, W Scott; Witherspoon, David J; Wu, Wilfred; Qin, Ga; Huff, Chad D; Jorde, Lynn B; Ge, Ri-Li

    2013-01-01

    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.

  20. 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.

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

    Indian Academy of Sciences (India)

    region of the H–K. Thus the main goals of this study are: (1) to generate a baseline database for high altitude lake level changes in H–K region using. ICESat/GLAS data, (2) to estimate volume gain or loss of the lakes during the study period, and. (3) to discuss the possible impact of climate variables on lake level changes.

  2. 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.

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

    African Journals Online (AJOL)

    total ventricle (TV) weight and the RV : TV ratio. The plasma T3 level ... The hypoxic conditions that occurred during the embryonic stage . which altered endogenous functions of prenatal chicks and affected several blood parameters, and oxygen supplementation at high altitude . improved chick quality. However, it did not ...

  4. Changes in labial capillary density on ascent to and descent from high altitude

    NARCIS (Netherlands)

    Gilbert-Kawai, Edward; Coppel, Jonny; Phillip, Hennis; Grocott, Michael; Ince, Can; Martin, Daniel

    2016-01-01

    Present knowledge of how the microcirculation is altered by prolonged exposure to hypoxia at high altitude is incomplete and modification of existing analytical techniques may improve our knowledge considerably. We set out to use a novel simplified method of measuring in vivo capillary density

  5. Life at the edge: Benthic invertebrates in high altitude Andean streams

    NARCIS (Netherlands)

    Loayza-Muro, R.A.

    2013-01-01

    High altitude Andean streams harbor a quite diverse benthic community represented by the major groups of invertebrates. Evidence is provided that abundant insect species have not been described taxonomically and that unique genotypes occur, probably as a result of the geological history of the Andes

  6. 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 ...

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

    NARCIS (Netherlands)

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

    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

  8. [Preconditions for a stay in high altitude areas in the case of existing health problems].

    Science.gov (United States)

    Willems, J H B M

    2004-11-06

    Various symptoms can arise during a stay in high altitude areas (above 2500 m), such as tissue hypoxia and in particular pulmonary and brain oedema. Patients with existing health problems can expect to develop more complaints or more severe complaints at an earlier stage. For a number of these patients a stay in high altitude areas should be advised against or should only take place if certain measures are taken. The advising physician should have knowledge about the reactions of the human body on hypoxy, and about (derailments of) the acclimatisation proces in high altitude areas. Every patient with a disease that can interfere with hypoxia should be assessed on an individual basis. The most important absolute and relative contraindications are cardiac and pulmonary conditions, haemoglobin abnormalities, diabetes mellitus, hypertension, epilepsy, severe obesity, kidney diseases and pregnancy. In the case of an existing health problem, a stay in high altitude should only be considered if medical care can be quickly and adequately provided on the spot.

  9. Anti-Fatigue Effects of Methazolamide in High- Altitude Hypoxic Mice ...

    African Journals Online (AJOL)

    Anti-Fatigue Effects of Methazolamide in High- Altitude Hypoxic Mice. ... findings indicate that the administration of MTZ can prolong swimming capacity time and improve exercise tolerance as well as increase the content of liver glycogen, reduce the level of lactic acid in muscles, when compared with anoxic control group.

  10. High altitude illness in pilgrims after rapid ascent to 4380 M.

    Science.gov (United States)

    Zafren, Ken; Pun, Matiram; Regmi, Nirajan; Bashyal, Gobinda; Acharya, Bhuwan; Gautam, Subarna; Jamarkattel, Sujan; Lamichhane, Shankar Raj; Acharya, Suman; Basnyat, Buddha

    The goal of the study was to characterize high altitude illness in Nepali pilgrims. We kept standardized records at the Himalayan Rescue Association (HRA) Temporary Health Camp at Gosainkund Lake (4380 m) in the Nepal Himalaya during the annual Janai Purnima Festival in 2014. Records included rate of ascent and Lake Louise Score (LLS). We defined High Altitude Headache (HAH) as headache alone or LLS = 2. Acute Mountain Sickness (AMS) was LLS≥3. High Altitude Cerebral Edema (HACE) was AMS with ataxia or altered mental status. An estimated 10,000 pilgrims ascended rapidly, most in 1-2 days, from Dhunche (1960 m) to Gosainkund Lake (4380 m). We saw 769 patients, of whom 86 had HAH. There were 226 patients with AMS, including 11 patients with HACE. We treated patients with HACE using dexamethasone and supplemental oxygen prior to rapid descent. Each patient with HACE descended carried by a porter. There were no fatalities due to HACE. There were no cases of High Altitude Pulmonary Edema (HAPE). HAH and AMS were common in pilgrims ascending rapidly to 4380 m. There were 11 cases of HACE, treated with dexamethasone, supplemental oxygen and descent. There were no fatalities. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. High energy nucleonic component of cosmic rays at mountain altitudes

    CERN Document Server

    Stora, Raymond Félix

    The diffusion equations describing the unidimensional propagation of .the high energy nucleonic component of cosmic rays throughout the atmosphere are sol"V'ed under two assumptions: (l) The nucleon-nucleon collisions are described according to Fermi's therlnOdynamical model involving completely inelastic pion and.nucleon-antinucleon pair production. (2) A somewhat opposite assumption is made assuming partially elastic collisions without nucleon-anti.nucleon pair production. Due to the present inaccuracy of experiments, we are able to derive only tentati v.e conclusions. The values computed under both hypotheses for the absorption mean free path and the charged to neutral particles ratio are found in acceptable ranges when compared to experimental data. The diffeential energy spectrum at a given depth is always found steeper than the primary, and steeper than indicated by experimental values if the primary is taken proportional to the 2.5 inverse power of energy.

  12. Nighttime chemistry at a high altitude site above Hong Kong

    Science.gov (United States)

    Brown, Steven S.; Dubé, William P.; Tham, Yee Jun; Zha, Qiaozhi; Xue, Likun; Poon, Steven; Wang, Zhe; Blake, Donald R.; Tsui, Wilson; Parrish, David D.; Wang, Tao

    2016-03-01

    Nighttime reactions of nitrogen oxides influence ozone, volatile organic compounds, and aerosol and are thus important to the understanding of regional air quality. Despite large emissions and rapid recent growth of nitrogen oxide concentrations, there are few studies of nighttime chemistry in China. Here we present measurements of nighttime nitrogen oxides, NO3 and N2O5, from a coastal mountaintop site in Hong Kong adjacent to the megacities of the Pearl River Delta region. This is the first study of nighttime chemistry from a site within the residual layer in China. Key findings include the following. First, highly concentrated urban NOx outflow from the Pearl River Delta region was sampled infrequently at night, with N2O5 mixing ratios up to 8 ppbv (1 min average) or 12 ppbv (1 s average) in nighttime aged air masses. Second, the average N2O5 uptake coefficient was determined from a best fit to the available steady state lifetime data as γ(N2O5) = 0.014 ± 0.007. Although this determination is uncertain due to the difficulty of separating N2O5 losses from those of NO3, this value is in the range of previous residual layer determinations of N2O5 uptake coefficients in polluted air in North America. Third, there was a significant contribution of biogenic hydrocarbons to NO3 loss inferred from canister samples taken during daytime. Finally, daytime N2O5 mixing ratios were in accord with their predicted photochemical steady state. Heterogeneous uptake of N2O5 in fog is determined to be an important production mechanism for soluble nitrate, even during daytime.

  13. Spatial and temporal variations of the high-altitude cusp precipitation

    Directory of Open Access Journals (Sweden)

    Z. Němeček

    2004-07-01

    Full Text Available Structured dispersion patterns of the ion precipitation in low- and mid-altitude cusp regions have been reported by many authors. These patterns are interpreted either as temporal features in terms of the pulsed reconnection model or as spatial changes caused by a combination of the particle velocity with the convection of magnetic field lines. It is generally expected that the spatial dispersion is predominantly observed in lower altitudes where the spacecraft crosses a wide range of geomagnetic coordinates in a short time, whereas the high-altitude spacecraft observes temporal changes because it stays nearly on the same field line for a long time. We have analyzed one pass of the INTERBALL-1/MAGION-4 satellite pair through the high-altitude cusp and found that both temporal and spatial dispersion effects are important even in the magnetopause vicinity. The analysis of the present event shows a spatial nature of the observed dispersion in the LLBL and in the plasma mantle. We have identified two sources of a mantle precipitation operating simultaneously. Our investigations suggest that besides already reported latitudinal dispersion, the longitudinal dispersion can be observed during intervals of sufficiently high east-west interplanetary magnetic field component.

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

    Science.gov (United States)

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

  15. High altitude flights by ruddy shelduck Tadorna ferruginea during trans-Himalayan migrations

    Science.gov (United States)

    Parr, N.; Bearhop, S.; Douglas, David C.; Takekawa, J.Y.; Prosser, Diann J.; Newman, S.H.; Perry, W.M.; Balachandran, S.; Witt, M.J.; Hou, Y.; Luo, Z.; Hawkes, L.A.

    2017-01-01

    Birds that migrate across high altitude mountain ranges are faced with the challenge of maintaining vigorous exercise in environments with limited oxygen. Ruddy shelducks are known to use wintering grounds south of the Tibetan Plateau at sea level and breeding grounds north of Himalayan mountain range. Therefore, it is likely these shelducks are preforming high altitude migrations. In this study we analyse satellite telemetry data collected from 15 ruddy shelduck from two populations wintering south of the Tibetan Plateau from 2007 to 2011. During north and south migrations ruddy shelduck travelled 1481 km (range 548–2671 km) and 1238 km (range 548–2689 km) respectively. We find mean maximum altitudes of birds in flight reached 5590 m (range of means 4755–6800 m) and mean maximum climb rates of 0.45 m s–1 (range 0.23–0.74 m s–1). The ruddy shelduck is therefore an extreme high altitude migrant that has likely evolved a range of physiological adaptations in order to complete their migrations.

  16. 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.

  17. 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

  18. Solar multi-conjugate adaptive optics based on high order ground layer adaptive optics and low order high altitude correction.

    Science.gov (United States)

    Zhang, Lanqiang; Guo, Youming; Rao, Changhui

    2017-02-20

    Multi-conjugate adaptive optics (MCAO) is the most promising technique currently developed to enlarge the corrected field of view of adaptive optics for astronomy. In this paper, we propose a new configuration of solar MCAO based on high order ground layer adaptive optics and low order high altitude correction, which result in a homogeneous correction effect in the whole field of view. An individual high order multiple direction Shack-Hartmann wavefront sensor is employed in the configuration to detect the ground layer turbulence for low altitude correction. Furthermore, the other low order multiple direction Shack-Hartmann wavefront sensor supplies the wavefront information caused by high layers' turbulence through atmospheric tomography for high altitude correction. Simulation results based on the system design at the 1-meter New Vacuum Solar Telescope show that the correction uniform of the new scheme is obviously improved compared to conventional solar MCAO configuration.

  19. Hemodynamic characteristics of high-altitude headache following acute high altitude exposure at 3700 m in young Chinese men.

    Science.gov (United States)

    Bian, Shi-Zhu; Jin, Jun; Li, Qian-Ning; Yu, Jie; Tang, Cai-Fa; Rao, Rong-Sheng; Yu, Shi-Yong; Zhao, Xiao-Hui; Qin, Jun; Huang, Lan

    2015-01-01

    This study aimed to identify the systemic and cerebral hemodynamic characteristics and their roles in high-altitude headache (HAH) among young Chinese men following acute exposure. The subjects (n = 385) were recruited in June and July of 2012. They completed case report form questionnaires, as well as heart rate (HR), blood pressure, echocardiogram and transcranial Doppler examinations at 3700 m following a two-hour plane flight. A subgroup of 129 participants was examined at two altitudes (500 and 3700 m). HAH was characterized by increased HR and cardiac output (CO) and lower saturation pulse oxygen (SpO(2)) (all p V(m)), systolic (V(s)) and diastolic (V(d)) velocities in the basilar artery (BA; all p V(d) ( 25.96 ± 4.97 cm/s vs. 24.76 ± 4.76 cm/s, p = 0.045) in the left vertebral artery (VA). The bilateral VA asymmetry was also significantly different between the two groups. The pulsatility index (PI) and resistance index (RI) of left VA were lower in the HAH subjects (p p V(d) difference between bilateral VAs) were independent risk factors for HAH at 3700 m. HAH was characterized, in part, by increased systemic hemodynamics and posterior cerebral circulation, which was reflected by the BA and left VA velocities, and lower arterial resistance and compliance. Furthermore, baseline CO and V(m) in left VA or right MCA at sea level were independent predictors for HAH, whilst bilateral VA asymmetry may contribute to the development of HAH at high altitude.

  20. High anthropogenic volatile organic compounds over a high altitude Himalayan station in eastern India

    Science.gov (United States)

    Sarkar, Chirantan; Chatterjee, Abhijit; Ghosh, Sanjay; Raha, Sibaji; Majumdar, Dipanjali; Srivastava, Anjali

    A first ever study on the characterization of anthropogenic volatile organic compounds has been made over eastern part of Himalaya in India. Measurements were carried out for a year-long period (2010- 2011) over Darjeeling (27.01 (°) N, 88.15 (°) E), a high altitude (2200 a msl) station over eastern Himalaya. A total of 96 samples were collected separately for day (6 A.M - 6 P.M.) and night time (6 P.M. - 6 A.M.) and anlysed for 20 VOCs using GC-MS. The annual average concentration of total anthropogenic VOC was 871 muµgm-3. VOC shows a distinct seasonal variation with the maximum concentration of 3254 muµgm-3 during postmonsoon (October-November) followed by 120 muµgm-3 during monsoon (June-September), 72 muµgm-3 during winter (December-February) and minimum concentration of 39 muµgm-3 during premonsoon (March-May). Styrene was found to be the most abundant VOC followed by benzene, toluene, ethyl benzene, xylene (BTEX) and chloroform. Styrene alone contributed 50 % to the total VOC whereas BTEX contributed 47 %. Styrene was found to be much higher in concentration compared to other high altitude stations and metro-cities in India. Earlier, biomass burning during night-time was used to be a common practice over Darjeeling like any other hill stations, but now-a-days, burning of plastics, tyres and other polystyrene products has become a common practice to get warmth against cold. This could significantly generate styrene in the atmosphere. Night time concentration was found to be higher than day time concentration for most of the VOCs through out the year. Higher solar radiation, high surface ozone and OH radical concentration could oxidise/destruct VOCs resulting to minimum concentration during premonsoon. Very high mixing layer depth and higher wind speed during premonsoon compared to other seasons favours ventilation and dispersion of VOCs from the sampling station. On the other hand, higher vehicular activities associated to high influx of tourists and

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

    Directory of Open Access Journals (Sweden)

    Shen Guanghao

    2012-08-01

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

  2. EPAS1 variants in high altitude Tibetan wolves were selectively introgressed into highland dogs

    Directory of Open Access Journals (Sweden)

    Bridgett vonHoldt

    2017-07-01

    Full Text Available Background Admixture can facilitate adaptation. For example, black wolves have obtained the variant causing black coat color through past hybridization with domestic dogs and have higher fitness than gray colored wolves. Another recent example of the transfer of adaptive variation between the two species has been suggested by the similarity between high altitude Tibetan mastiffs and wolves at the EPAS1 gene, a transcription factor induced in low oxygen environments. Methods Here, we investigate the directionality of admixture in EPAS1 between 28 reference highland gray wolves, 15 reference domestic dogs, and 21 putatively admixed highland wolves. This experimental design represents an expanded sample of Asian dogs and wolves from previous studies. Admixture was inferred using 17,709 publicly available SNP genotypes on canine chromosome 10. We additionally conducted a scan for positive selection in the highland dog genome. Results We find an excess of highland gray wolf ancestry at the EPAS1 locus in highland domestic dogs, suggesting adaptive introgression from wolves to dogs. The signal of admixture is limited in genomic extent to a small region on chromosome 10, indicating that it is the focus of selection in an oxygen-limited environment. Discussion Our results suggest that an adaptive variant of EPAS1 in highland wolves was transferred to highland dogs, carrying linked variants that potentially function in hypoxia response at high elevation. The intertwined history of dogs and wolves ensures a unique evolutionary dynamic where variants that have appeared in the history of either species can be tested for their effects on fitness under natural and artificial selection. Such coupled evolutionary histories may be key to the persistence of wild canines and their domesticated kin given the increasing anthropogenic modifications that characterize the future of both species.

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

    NARCIS (Netherlands)

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

    2006-01-01

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

  4. 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

  5. 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

  6. Observational Study of Neural Respiratory Drive During Sleep at High Altitude.

    Science.gov (United States)

    Steier, Joerg; Cade, Nic; Walker, Ben; Moxham, John; Jolley, Caroline

    2017-09-01

    Steier, Joerg, Nic Cade, Ben Walker, John Moxham, and Caroline Jolley. Observational study of neural respiratory drive during sleep at high altitude. High Alt Med Biol. 18:242-248, 2017. Ventilation at altitude changes due to altered levels of pO 2 , pCO 2 and the effect on blood pH. Nocturnal ventilation is particularly exposed to these changes. We hypothesized that an increasing neural respiratory drive (NRD) is associated with the severity of sleep-disordered breathing at altitude. Mountaineers were studied at sea level (London, United Kingdom), and at altitude at the Aconcagua (Andes, Argentina). NRD was measured as electromyogram of the diaphragm (EMGdi) overnight by a transesophageal multi-electrode catheter; results were reported for sea level, 3,380 m, 4,370 m, and 5,570 m. Four healthy subjects (3 men, age 31(3)years, body mass index 23.6(0.9)kg/m 2 , neck circumference 37.0(2.7)cm, forced expiratory volume in 1 second 111.8(5.1)%predicted, and forced vital capacity 115.5(6.3)%predicted) were studied. No subject had significant sleep abnormalities at sea level. Time to ascent to 3,380 m was 1 day, to 4,370 m was 5 days, and the total nights at altitude were 21 days. The oxygen desaturation index (4% oxygen desaturation index [ODI] 0.8(0.4), 22.0 (7.2), 61.4 (26.9), 144.9/hour, respectively) and the EMGdi (5.2 (1.9), 12.8 (5.1), 14.1 (3.4), 18.5%, respectively) increased with the development of periodic breathing at altitude, whereas the average SpO 2 declined (97.5 (1.3), 84.8 (0.5), 81.0 (4.1), 68.5%, respectively). The average EMGdi correlated well with the 4%ODI (r = 0.968, p = 0.032). NRD sleep increases at altitude in relation to the severity of periodic breathing.

  7. Gene expression variations in high-altitude adaptation: a case study of the Asiatic toad (Bufo gargarizans).

    Science.gov (United States)

    Yang, Weizhao; Qi, Yin; Lu, Bin; Qiao, Liang; Wu, Yayong; Fu, Jinzhong

    2017-07-03

    Genome-wide investigation of molecular mechanisms for high-altitude adaptation has attracted great attention in the last few years. In order to understand the contribution of gene expression level variations to high-altitude adaptation in Asiatic toads (Bufo gargarizans), we implemented a reciprocal transplant experiment between low- and high-altitude sites and sequenced 12 transcriptomes from brain, heart, and liver tissues. A large number of genes with expression differences (DEGs) between high- and low-altitude individuals (193 fixed and 844 plastic) were identified, and the majority of them were tissue specific. Heart displayed the largest number of DEGs, both plastic and fixed. Fixed DEGs were particularly concentrated in functions associated with muscle contraction, and the majority of them were down-regulated in high-altitude individuals. Plastic DEGs were highly concentrated in several energy metabolism related functional categories, and the majority of them were also down-regulated at high-altitude environments. In liver samples, genes associated with nutrient metabolism experienced a broad-scale expression down-regulation in high-altitude toads. These broadly suppressed expression patterns at high altitudes are in strong contrast to those of endothermic homeotherms, suggesting poikilothermic vertebrates may have adopted different strategies at high altitudes. Our results strongly support that both genotypic specialization and phenotypic plasticity play crucial role in adaptation to high altitude for Asiatic toads. Poikilothermic vertebrates are among the most hypoxia-tolerant animals known, and many molecular mechanisms remain elusive. We hope that our results will provide useful directions for future research.

  8. 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

  9. 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.

  10. Highly cross-linked nanoporous polymers

    Science.gov (United States)

    Steckle, Jr., Warren P.; Apen, Paul G.; Mitchell, Michael A.

    1997-01-01

    Condensation polymerization followed by a supercritical extraction step can be used to obtain highly cross-linked nanoporous polymers with high surface area, controlled pore sizes and rigid structural integrity. The invention polymers are useful for applications requiring separation membranes.

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

    Science.gov (United States)

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

    2016-02-23

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

  12. Contribution of a mutational hot spot to hemoglobin adaptation in high-altitude Andean house wrens.

    Science.gov (United States)

    Galen, Spencer C; Natarajan, Chandrasekhar; Moriyama, Hideaki; Weber, Roy E; Fago, Angela; Benham, Phred M; Chavez, Andrea N; Cheviron, Zachary A; Storz, Jay F; Witt, Christopher C

    2015-11-10

    A key question in evolutionary genetics is why certain mutations or certain types of mutation make disproportionate contributions to adaptive phenotypic evolution. In principle, the preferential fixation of particular mutations could stem directly from variation in the underlying rate of mutation to function-altering alleles. However, the influence of mutation bias on the genetic architecture of phenotypic evolution is difficult to evaluate because data on rates of mutation to function-altering alleles are seldom available. Here, we report the discovery that a single point mutation at a highly mutable site in the β(A)-globin gene has contributed to an evolutionary change in hemoglobin (Hb) function in high-altitude Andean house wrens (Troglodytes aedon). Results of experiments on native Hb variants and engineered, recombinant Hb mutants demonstrate that a nonsynonymous mutation at a CpG dinucleotide in the β(A)-globin gene is responsible for an evolved difference in Hb-O2 affinity between high- and low-altitude house wren populations. Moreover, patterns of genomic differentiation between high- and low-altitude populations suggest that altitudinal differentiation in allele frequencies at the causal amino acid polymorphism reflects a history of spatially varying selection. The experimental results highlight the influence of mutation rate on the genetic basis of phenotypic evolution by demonstrating that a large-effect allele at a highly mutable CpG site has promoted physiological differentiation in blood O2 transport capacity between house wren populations that are native to different elevations.

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

    Directory of Open Access Journals (Sweden)

    Kangwen Sun

    2015-01-01

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

  14. Changes in body fluid compartments on re-induction to high altitude and effect of diuretics

    Science.gov (United States)

    Singh, M. V.; Rawal, S. B.; Tyagi, A. K.; Bhagat, Maj J. K.; Parshad, R.; Divekar, H. M.

    1988-03-01

    Studies were carried out in 29 healthy young adults in the Indian Army stationed in the plains and posted at an elevation of 3500 m for more than 6 months. After exposure to a low elevation in Delhi (260 m) for 3 weeks they were reinduced to a height of 3500 m. The subjects were divided into three groups, each of which was treated with either placebo or acetazolamide or spironolactone. The drug treatment was started immediately after their landing at high altitude and continued for 2 days only. Total body water, extracellular fluid, intracellular fluid, plasma volume, blood pH, PaO2, PaCO2 and blood viscosity were determined on exposure at Delhi and on re-induction to high altitude. Plasma volume was increased after the descent from high altitude and remained high for up to 21 day's study. This increased plasma volume may have some significance in the pathogenesis of pulmonary oedema. Total body water and intracellular fluid content were increased at 260 m elevation, while extracellular fluid decreased. On re-induction there was a decrease in total body water with no change in the extracellular fluid content.

  15. Development and demonstration flight of a fuel cell system for high-altitude balloons

    Science.gov (United States)

    Uno, Masatoshi; Shimada, Takanobu; Ariyama, Yusuke; Fukuzawa, Naoya; Noguchi, Daisuke; Ogawa, Keita; Naito, Hitoshi; Sone, Yoshitsugu; Saito, Yoshitaka

    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.

  16. The molecular basis of convergence in hemoglobin function in high-altitude Andean birds

    DEFF Research Database (Denmark)

    Storz, Jay; Natarajan, Chandrasekhar; Witt, Christopher C.

    2016-01-01

    . For example, in high-altitude ertebrates that have convergently evolved elevated Hb-O2 affinities, Perutz’s hypothesis predicts that parallel amino acid substitutions should be pervasive. We investigated the predictability of genetic adaptation by examining the molecular basis of convergence in hemoglobin (Hb......Max Perutz predicted that adaptive changes in functional properties of vertebrate hemoglobin (Hb) would typically be attributable to a small number of substitutions at key residue positions (1983, Mol. Biol. Evol.). According to Perutz, amino acid substitutions that can be expected to make......) function in comparisons involving 56 avian taxa that have contrasting altitudinal range limits. Convergent increases in Hb-O2 affinity were pervasive among high-altitude taxa, but few such changes were attributable to parallel amino acid substitutions at key residues. Thus, predictable changes...

  17. 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

  18. Genetic variants in EPAS1 contribute to adaptation to high-altitude hypoxia in Sherpas.

    Directory of Open Access Journals (Sweden)

    Masayuki Hanaoka

    Full Text Available Sherpas comprise a population of Tibetan ancestry in the Himalayan region that is renowned for its mountaineering prowess. The very small amount of available genetic information for Sherpas is insufficient to explain their physiological ability to adapt to high-altitude hypoxia. Recent genetic evidence has indicated that natural selection on the endothelial PAS domain protein 1 (EPAS1 gene was occurred in the Tibetan population during their occupation in the Tibetan Plateau for millennia. Tibetan-specific variations in EPAS1 may regulate the physiological responses to high-altitude hypoxia via a hypoxia-inducible transcription factor pathway. We examined three significant tag single-nucleotide polymorphisms (SNPs, rs13419896, rs4953354, and rs4953388 in the EPAS1 gene in Sherpas, and compared these variants with Tibetan highlanders on the Tibetan Plateau as well as with non-Sherpa lowlanders. We found that Sherpas and Tibetans on the Tibetan Plateau exhibit similar patterns in three EPAS1 significant tag SNPs, but these patterns are the reverse of those in non-Sherpa lowlanders. The three SNPs were in strong linkage in Sherpas, but in weak linkage in non-Sherpas. Importantly, the haplotype structured by the Sherpa-dominant alleles was present in Sherpas but rarely present in non-Sherpas. Surprisingly, the average level of serum erythropoietin in Sherpas at 3440 m was equal to that in non-Sherpas at 1300 m, indicating a resistant response of erythropoietin to high-altitude hypoxia in Sherpas. These observations strongly suggest that EPAS1 is under selection for adaptation to the high-altitude life of Tibetan populations, including Sherpas. Understanding of the mechanism of hypoxia tolerance in Tibetans is expected to provide lights to the therapeutic solutions of some hypoxia-related human diseases, such as cardiovascular disease and cancer.

  19. Long term picoplankton dynamics in a warm-monomictic, tropical high altitude lake

    OpenAIRE

    Alfonso LUGO VÁZQUEZ; Gloria VILACLARA FATJÓ; Laura PERALTA SORIANO; María Elena MARTÍNEZ-PÉREZ; Alcocer, Javier; Macek, Miroslav

    2009-01-01

    Long term analyses of the microbial loop, centred on the picoplankton dynamics, were carried out over a five-year (1998 to 2002) period in Lake Alchichica (Puebla, Mexico), a high altitude tropical athalassohaline lake. The hydrodynamics of the lake followed a warm-monomictic pattern with mixing at a minimum temperature during the early dry season while the stratification was pronounced in the late dry season and throughout the rainy season; anoxic conditions in the hypolimnion lasted

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

    Science.gov (United States)

    Weinstein, Karen J

    2007-09-01

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

  1. EPAS1 variants in high altitude Tibetan wolves were selectively introgressed into highland dogs

    OpenAIRE

    Bridgett vonHoldt; Zhenxin Fan; Diego Ortega-Del Vecchyo; Wayne, Robert K.

    2017-01-01

    Background Admixture can facilitate adaptation. For example, black wolves have obtained the variant causing black coat color through past hybridization with domestic dogs and have higher fitness than gray colored wolves. Another recent example of the transfer of adaptive variation between the two species has been suggested by the similarity between high altitude Tibetan mastiffs and wolves at the EPAS1 gene, a transcription factor induced in low oxygen environments. Methods Here, we investiga...

  2. The Theater High Altitude Area Defense program: an interim examination of its acquisition strategy

    OpenAIRE

    Atkinson, James W.

    1996-01-01

    Approved for public release; distribution in unlimited. This thesis is an examination of the Theater High Altitude Area Defense (THAAD) program's implementation of the User Operational Evaluation System (UOES) acquisition strategy. The Missile Defense Act of 1991 imposed significant schedule risk on THAAD's development, necessitating the UOES strategy. The UOES risk management issues are analyzed using DOD's risk management guidance. This guidance incorporates some current methods, applica...

  3. Approximate solutions of range for constant altitude - constant high subsonic speed flight of transport aircraft

    Energy Technology Data Exchange (ETDEWEB)

    Cavcar, A.; Cavcar, M. [Anadolu Univ., School of Civil Aviation, Eskisehir, (Turkey)

    2004-09-01

    Approximate cruise range solutions are introduced for the constant altitude constant high subsonic speed flight of turbojet/fan transport aircraft with cambered wing design. The variation of the specific fuel consumption with Mach number is also considered in derivation of the approximate solutions. The method aims at estimation of the cruise range of aircraft during conceptual or preliminary design phase. An application of the solutions is also presented. (author)

  4. Space-quality data from balloon-borne telescopes: the High Altitude Lensing Observatory (HALO)

    OpenAIRE

    Rhodes, Jason; Dobke, Benjamin; Booth, Jeffrey; Massey, Richard; Liewer, Kurt; Smith, Roger; Amara, Adam; Aldrich, Jack; Berge, Joel; Bezawada, Naidu; Brugarolas, Paul; Clark, Paul; Dubbeldam, Cornelis M.; Ellis, Richard; Frenk, Carlos

    2012-01-01

    We present a method for attaining sub-arcsecond pointing stability during sub-orbital balloon flights, as designed for in the High Altitude Lensing Observatory (HALO) concept. The pointing method presented here has the potential to perform near-space quality optical astronomical imaging at ~1–2% of the cost of space-based missions. We also discuss an architecture that can achieve sufficient thermo-mechanical stability to match the pointing stability. This concept is motivated by a...

  5. Comparing plasma bubble occurrence rates at CHAMP and GRACE altitudes during high and low solar activity

    Directory of Open Access Journals (Sweden)

    C. Xiong

    2010-09-01

    Full Text Available Based on the multi-year data base (2001–2009 of CHAMP Planar Langmuir Probe (PLP data and GRACE K-Band Ranging (KBR1B data, typical features of ionospheric plasma irregularities are studied at the altitudes of CHAMP (300–400 km and GRACE (~500 km. The phenomena we are focusing on are the equatorial plasma bubbles (EPBs. Similar seasonal/longitudinal (S/L distributions of EPB have been found at both CHAMP and GRACE altitudes during solar active and quiet years. Peak EPB occurrence rates, defined as number of events within an S/L bin divided by the number of passes over that bin, decrease from the high and moderate solar flux period (2001–2005 to the low solar flux period (2005–2009 from 80% to 60% and 60% to 40% at CHAMP and GRACE altitudes, respectively. On average the occurrence rate increases linearly with solar flux at about the same rate at CHAMP and GRACE. For high flux levels (P10.7>200 non-linear increases are observed at GRACE. The occurrence rate increases rapidly after 19:00 local time (LT during high solar flux periods. Around solar minimum rates increase more gently and peak around 22:00 LT. The highest occurrence rates are encountered at latitudes around 10° north and south of the dip equator. Results from the two altitudes support the notion that EPBs form regions of depleted plasma along geomagnetic fluxtubes. It is shown for the first time that in regions of high occurrence rates EPBs are associated with fluxtubes reaching greater apex heights than those in regions of low rates.

  6. Correlations between the simulated military tasks performance and physical fitness tests at high altitude

    Directory of Open Access Journals (Sweden)

    Eduardo Borba Neves

    2017-11-01

    Full Text Available The aim of this study was to investigate the Correlations between the Simulated Military Tasks Performance and Physical Fitness Tests at high altitude. This research is part of a project to modernize the physical fitness test of the Colombian Army. Data collection was performed at the 13th Battalion of Instruction and Training, located 30km south of Bogota D.C., with a temperature range from 1ºC to 23ºC during the study period, and at 3100m above sea level. The sample was composed by 60 volunteers from three different platoons. The volunteers start the data collection protocol after 2 weeks of acclimation at this altitude. The main results were the identification of a high positive correlation between the 3 Assault wall in succession and the Simulated Military Tasks performance (r = 0.764, p<0.001, and a moderate negative correlation between pull-ups and the Simulated Military Tasks performance (r = -0.535, p<0.001. It can be recommended the use of the 20-consecutive overtaking of the 3 Assault wall in succession as a good way to estimate the performance in operational tasks which involve: assault walls, network of wires, military Climbing Nets, Tarzan jump among others, at high altitude.

  7. Genetic signatures reveal high-altitude adaptation in a set of ethiopian populations.

    Science.gov (United States)

    Huerta-Sánchez, Emilia; Degiorgio, Michael; Pagani, Luca; Tarekegn, Ayele; Ekong, Rosemary; Antao, Tiago; Cardona, Alexia; Montgomery, Hugh E; Cavalleri, Gianpiero L; Robbins, Peter A; Weale, Michael E; Bradman, Neil; Bekele, Endashaw; Kivisild, Toomas; Tyler-Smith, Chris; Nielsen, Rasmus

    2013-08-01

    The Tibetan and Andean Plateaus and Ethiopian highlands are the largest regions to have long-term high-altitude residents. Such populations are exposed to lower barometric pressures and hence atmospheric partial pressures of oxygen. Such "hypobaric hypoxia" may limit physical functional capacity, reproductive health, and even survival. As such, selection of genetic variants advantageous to hypoxic adaptation is likely to have occurred. Identifying signatures of such selection is likely to help understanding of hypoxic adaptive processes. Here, we seek evidence of such positive selection using five Ethiopian populations, three of which are from high-altitude areas in Ethiopia. As these populations may have been recipients of Eurasian gene flow, we correct for this admixture. Using single-nucleotide polymorphism genotype data from multiple populations, we find the strongest signal of selection in BHLHE41 (also known as DEC2 or SHARP1). Remarkably, a major role of this gene is regulation of the same hypoxia response pathway on which selection has most strikingly been observed in both Tibetan and Andean populations. Because it is also an important player in the circadian rhythm pathway, BHLHE41 might also provide insights into the mechanisms underlying the recognized impacts of hypoxia on the circadian clock. These results support the view that Ethiopian, Andean, and Tibetan populations living at high altitude have adapted to hypoxia differently, with convergent evolution affecting different genes from the same pathway.

  8. 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

  9. Growth of children in two economically diverse Peruvian high-altitude communities.

    Science.gov (United States)

    Pawson, I G; Huicho, L; Muro, M; Pacheco, A

    2001-01-01

    The growth of children living in two high-altitude communities associated with an active copper mine in southern Peru was examined. In the community directly associated with mining operations, nutritional and health conditions were believed to be relatively favorable as a result of the substantial mine-related infrastructure that had developed over the previous 12 years. In contrast, few such benefits were available in the other community, which provides limited part-time labor at the mine. Anthropometric data, including measurements of height, weight, skinfold thicknesses, upper arm circumference, and chest dimensions, and determination of bone age, were collected from a total of 880 children between the ages of 4 and 18 years. There were significant differences between the two communities, with those in the mining community exhibiting significantly greater height and weight, a higher level of body fat, and more rapid skeletal development. Among children over the age of 12 years, a plateau in height was seen, suggesting that the benefits to growth resulting from mining-related development were more noticeable in younger children. Compared with Peruvian high-altitude populations examined during the 1960s, both samples from the present study were substantially taller and heavier, suggesting that despite local differences in socioeconomic conditions between the communities studied, overall conditions for growth are generally more favorable than those that existed among Peruvian high-altitude populations surveyed in the 1960s.

  10. Freestanding Flag-Type Triboelectric Nanogenerator for Harvesting High-Altitude Wind Energy from Arbitrary Directions.

    Science.gov (United States)

    Zhao, Zhenfu; Pu, Xiong; Du, Chunhua; Li, Linxuan; Jiang, Chunyan; Hu, Weiguo; Wang, Zhong Lin

    2016-02-23

    Wind energy at a high altitude is far more stable and stronger than that near the ground, but it is out of reach of the wind turbine. Herein, we develop an innovative freestanding woven triboelectric nanogenerator flag (WTENG-flag) that can harvest high-altitude wind energy from arbitrary directions. The wind-driven fluttering of the woven unit leads to the current generation by a coupled effect of contact electrification and electrostatic induction. Systematic study is conducted to optimize the structure/material parameters of the WTENG-flag to improve the power output. This 2D WTENG-flag can also be stacked in parallel connections in many layers for a linearly increased output. Finally, a self-powered high-altitude platform with temperature/humidity sensing/telecommunicating capability is demonstrated with the WTENG-flag as a power source. Due to the light weight, low cost, and easy scale-up, this WTENG-flag has great potential for applications in weather/environmental sensing/monitoring systems.

  11. The Yak genome database: an integrative database for studying yak biology and high-altitude adaption

    Directory of Open Access Journals (Sweden)

    Hu Quanjun

    2012-11-01

    Full Text Available Abstract Background The yak (Bos grunniens is a long-haired bovine that lives at high altitudes and is an important source of milk, meat, fiber and fuel. The recent sequencing, assembly and annotation of its genome are expected to further our understanding of the means by which it has adapted to life at high altitudes and its ecologically important traits. Description The Yak Genome Database (YGD is an internet-based resource that provides access to genomic sequence data and predicted functional information concerning the genes and proteins of Bos grunniens. The curated data stored in the YGD includes genome sequences, predicted genes and associated annotations, non-coding RNA sequences, transposable elements, single nucleotide variants, and three-way whole-genome alignments between human, cattle and yak. YGD offers useful searching and data mining tools, including the ability to search for genes by name or using function keywords as well as GBrowse genome browsers and/or BLAST servers, which can be used to visualize genome regions and identify similar sequences. Sequence data from the YGD can also be downloaded to perform local searches. Conclusions A new yak genome database (YGD has been developed to facilitate studies on high-altitude adaption and bovine genomics. The database will be continuously updated to incorporate new information such as transcriptome data and population resequencing data. The YGD can be accessed at http://me.lzu.edu.cn/yak.

  12. New insights of aquaporin 5 in the pathogenesis of high altitude pulmonary edema.

    Science.gov (United States)

    She, Jun; Bi, Jing; Tong, Lin; Song, Yuanlin; Bai, Chunxue

    2013-11-25

    High altitude pulmonary edema (HAPE) affects individuals and is characterized by alveolar flooding with protein-rich edema as a consequence of blood-gas barrier disruption. In this study, we hypothesized that aquaporin 5 (AQP5) which is one kind of water channels may play a role in preservation of alveolar epithelial barrier integrity in high altitude pulmonary edema (HAPE). Therefore, we established a model in Wildtype mice and AQP5 -/- mice were assingned to normoxic rest (NR), hypoxic rest (HR) and hypoxic exercise (HE) group. Mice were produced by training to walk at treadmill for exercising and chamber pressure was reduced to simulate climbing an altitude of 5000 m for 48 hours. Studies using BAL in HAPE mice to demonstrated that edema is caused leakage of albumin proteins and red cells across the alveolarcapillary barrier in the absence of any evidence of inflammation. In this study, the Lung wet/dry weight ratio and broncholalveolar lavage protein concentrations were slightly increased in HE AQP5 -/- mice compared to wildtype mice. And histologic evidence of hemorrhagic pulmonary edema was distinctly shown in HE group. The lung Evan's blue permeability of HE group was showed slightly increased compare to the wildtype groups, and HR group was showed a medium situation from normal to HAPE development compared with NR and HE group. Deletion of AQP5 slightly increased lung edema and lung injury compared to wildtype mice during HAPE development, which suggested that the AQP5 plays an important role in HAPE formation induced by high altitude simulation.

  13. Respiratory mechanics and morphology of Tibetan and Andean high-altitude geese with divergent life histories.

    Science.gov (United States)

    York, Julia M; Scadeng, Miriam; McCracken, Kevin G; Milsom, William K

    2018-01-10

    High-altitude bar-headed geese (Anser indicus) and Andean geese (Chloephaga melanoptera) have been shown to preferentially increase tidal volume over breathing frequency when increasing ventilation during exposure to hypoxia. Increasing tidal volume is a more effective breathing strategy but is also thought to be more mechanically and metabolically expensive. We asked whether there might be differences in the mechanics or morphology of the respiratory systems of high-altitude transient bar-headed geese and high-altitude resident Andean geese that could minimize the cost of breathing more deeply. We compared these two species with a low-altitude migratory species, the barnacle goose (Branta leucopsis). We ventilated anesthetized birds to measure mechanical properties of the respiratory system and used CT scans to quantify respiratory morphology. We found that the respiratory system of Andean geese was disproportionately larger than that of the other two species, allowing use of a deeper breathing strategy for the same energetic cost. The relative size of the respiratory system, especially the caudal air sacs, of bar-headed geese was also larger than that of barnacle geese. However, when normalized to respiratory system size, the mechanical cost of breathing did not differ significantly among these three species, indicating that deeper breathing is enabled by morphological but not mechanical differences between species. The metabolic cost of breathing was estimated to be breathing was estimated to increase 7- to 10-fold in bar-headed and barnacle geese in severe hypoxia, but less than 1-fold in Andean geese exposed to the same low atmospheric PO2. © 2018. Published by The Company of Biologists Ltd.

  14. A novel candidate region for genetic adaptation to high altitude in Andean populations.

    Directory of Open Access Journals (Sweden)

    Guido Valverde

    Full Text Available Humans living at high altitude (≥ 2,500 meters above sea level have acquired unique abilities to survive the associated extreme environmental conditions, including hypoxia, cold temperature, limited food availability and high levels of free radicals and oxidants. Long-term inhabitants of the most elevated regions of the world have undergone extensive physiological and/or genetic changes, particularly in the regulation of respiration and circulation, when compared to lowland populations. Genome scans have identified candidate genes involved in altitude adaption in the Tibetan Plateau and the Ethiopian highlands, in contrast to populations from the Andes, which have not been as intensively investigated. In the present study, we focused on three indigenous populations from Bolivia: two groups of Andean natives, Aymara and Quechua, and the low-altitude control group of Guarani from the Gran Chaco lowlands. Using pooled samples, we identified a number of SNPs exhibiting large allele frequency differences over 900,000 genotyped SNPs. A region in chromosome 10 (within the cytogenetic bands q22.3 and q23.1 was significantly differentiated between highland and lowland groups. We resequenced ~1.5 Mb surrounding the candidate region and identified strong signals of positive selection in the highland populations. A composite of multiple signals like test localized the signal to FAM213A and a related enhancer; the product of this gene acts as an antioxidant to lower oxidative stress and may help to maintain bone mass. The results suggest that positive selection on the enhancer might increase the expression of this antioxidant, and thereby prevent oxidative damage. In addition, the most significant signal in a relative extended haplotype homozygosity analysis was localized to the SFTPD gene, which encodes a surfactant pulmonary-associated protein involved in normal respiration and innate host defense. Our study thus identifies two novel candidate genes and

  15. High Altitude Radiations Relevant to the High Speed Civil Transport (HSCT)

    Science.gov (United States)

    Wilson, J. W.; Goldhagan, P.; Maiden, D. L.; Tai, H.

    2004-01-01

    The Langley Research Center (LaRC) performed atmospheric radiation studies under the SST development program in which important ionizing radiation components were measured and extended by calculations to develop the existing atmospheric ionizing radiation (AIR) model. In that program the measured neutron spectrum was limited to less than 10 MeV by the available 1960-1970 instrumentation. Extension of the neutron spectrum to high energies was made using the LaRC PROPER-3C monte carlo code. It was found that the atmospheric neutrons contributed about half of the dose equivalent and approximately half of the neutron contribution was from high energy neutrons above 10 MeV. Furthermore, monte carlo calculations of solar particle events showed that potential exposures as large as 10-100 mSv/hr may occur on important high latitude routes but acceptable levels of exposure could be obtained if timely descent to subsonic altitudes could be made. The principal concern was for pregnant occupants onboard the aircraft. As a result of these studies the FAA Advisory Committee on the Radiobiological Aspects of the SST recommended: 1. Crew members will have to be informed of their exposure levels 2. Maximum exposures on any flight to be limited to 5 mSv 3. Airborne radiation detection devices for total exposure and exposure rates 4. Satellite monitoring system to provide SST aircraft real-time information on atmospheric radiation levels for exposure mitigation 5. A solar forecasting system to warn flight operations of an impending solar event for flight scheduling and alert status. These recommendations are a reasonable starting point to requirements for the HSCT with some modification reflecting new standards of protection as a result of changing risk coefficients.

  16. 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.

  17. Parametric study of microwave-powered high-altitude airplane platforms designed for linear flight

    Science.gov (United States)

    Morris, C. E. K., Jr.

    1981-01-01

    The performance of a class of remotely piloted, microwave powered, high altitude airplane platforms is studied. The first part of each cycle of the flight profile consists of climb while the vehicle is tracked and powered by a microwave beam; this is followed by gliding flight back to a minimum altitude above a microwave station and initiation of another cycle. Parametric variations were used to define the effects of changes in the characteristics of the airplane aerodynamics, the energy transmission systems, the propulsion system, and winds. Results show that wind effects limit the reduction of wing loading and the increase of lift coefficient, two effective ways to obtain longer range and endurance for each flight cycle. Calculated climb performance showed strong sensitivity to some power and propulsion parameters. A simplified method of computing gliding endurance was developed.

  18. Physico-chemical and environmental controls on siliceous sinter formation at the high-altitude El Tatio geothermal field, Chile

    Science.gov (United States)

    Nicolau, Constanza; Reich, Martin; Lynne, Bridget

    2014-08-01

    El Tatio geothermal field is located 4270 m above sea level in the Altiplano, northern Chile. Siliceous sinter deposits from El Tatio were studied to understand the influence of water chemistry and the extreme climatic conditions on their textures and mineralogy. The results of this study show that the mineralogy of El Tatio sinters include of opal-A and accessory minerals, such as halite, gypsum and cahnite (Ca4B2As2O12•4H2O), which precipitate by full evaporation of high arsenic, boron and calcium thermal waters. El Tatio sinters show a high degree of structural disorder, probably linked to cation incorporation into the silica structure and/or the occurrence of micro- to nano-scale accessory minerals. The high content of cations in the thermal waters is strongly tied to relatively high silica precipitation rates considering silica concentration in water (147-285 mg/l SiO2). Precipitation rate reach 2.5 kg/m2 per year based on in situ precipitation experiments. The particular environmental conditions of this high-altitude geothermal area that produce high water cooling rate and high evaporation rate, may also be responsible for the fast silica precipitation. Low environmental temperatures create freezing-related sinter textures (i.e., silica platelets and micro columns/ridges). Silicified microbial filaments are also characteristic of El Tatio sinters, and they are indicative of water temperature and hydrodynamic conditions at the moment of sinter formation. However, sinter textural interpretation in a high-altitude Andean context must be done carefully as specific relationships between microbial and hydrodynamic textures are found.

  19. Cultural factors affecting the demographic structure of a high altitude Nepalese population.

    Science.gov (United States)

    Weitz, C A; Pawson, I G; Weitz, M V; Lang, S D; Lang, A

    1978-01-01

    Surveys were undertaken to study the fertility of Sherpa and Tibetan women living at altitudes over 3400 meters in Nepal. 2 teams independently collected demographic data during 1970 and 1971. Of all women who reported their ages to be 15 years and older, 348 (37.0%) provided menarchial data, 294 (31.2%) related the age at which they first became pregnant, and 420 (44.6%) replied to questions on the number of live births, neonatal deaths, infant deaths, child deaths, and the number of living children. The average completed fertility (4.77 live births) and estimated crude birthrate (31-33/1000) are low relative to low altitude peasant populations as well as to high altitude Andean peasants. Environmental phenomena (hypoxia, iodine deficiency) may be associated with retarded menarchial age and high infant mortality, but the major factors causing the low fertility seem to be cultural rather than environmental. Traditional ceremonial requirements delay the age at marriage until the mid or late twenties. Male and female celibacy is promoted by religious practices. Migrant females and women married to migrant males report reduced fertility. This is possibly due to poor nutrition and health care. Nonmigrant women living in villages participating extensively in the cash economy have greater access to the growing market economy, health care, and education and report higher numbers of live births and fewer child deaths.

  20. Conjugate observations of ENA signals in the high-altitude cusp and proton auroral spot in the low-altitude cusp with IMAGE spacecraft

    Science.gov (United States)

    Suzuki, S.; Taguchi, S.; Hosokawa, K.; Collier, M. R.; Moore, T. E.; Frey, H. U.; Mende, S. B.

    2008-07-01

    On 28 April 2001, significant enhancements of neutral atom signals were detected in the direction of a high-altitude cusp by the Low-Energy Neutral Atom (LENA) imager onboard the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE). Simultaneously, proton auroral emission was observed in the low-altitude cusp by the Far-Ultraviolet Instrument (FUV) on the IMAGE spacecraft. The temporal variations of their intensities showed a good correlation, suggesting they had a common source. During a brief period, the proton auroral spot moved antisunward and dawnward in conjunction with the motion of the ionospheric footprint of the LENA cusp signal. The Tsyganenko-96 model shows that the possible source location of the LENA cusp signals maps to the FUV spot. Considering the solar wind variations, we have attributed this ``moving proton auroral spot'' to a moving flux tube that was created by transient reconnection on the dayside magnetopause and contained relatively high proton densities.

  1. A high-altitude balloon experiment to probe stratospheric electric fields from low latitudes

    Directory of Open Access Journals (Sweden)

    S. Gurubaran

    2017-02-01

    Full Text Available The Earth's electrical environment hosts a giant electrical circuit, often referred to as the global electric circuit (GEC, linking the various sources of electrical generators located in the lower atmosphere, the ionosphere and the magnetosphere. The middle atmosphere (stratosphere and mesosphere has been traditionally believed to be passively transmitting electric fields generated elsewhere. Some observations have reported anomalously large electric fields at these altitudes, and the scientific community has had to revisit the earlier hypothesis time and again. At stratospheric altitudes and especially at low latitudes, horizontal electric fields are believed to be of ionospheric origin. Though measurements of these fields from a balloon platform are challenging because of their small magnitudes (around a few mV m−1, a suitably designed long-duration balloon experiment capable of detecting such small fields can provide useful information on the time evolution of ionospheric electric fields, which is otherwise possible only using radar or satellite in situ measurements. We present herein details of one such experiment, BEENS (Balloon Experiment on the Electrodynamics of Near Space, carried out from a low-latitude site in India. The instrument package for this experiment is comprised of four deployable booms for measurements of horizontal electric fields and one inclined boom for vertical electric field measurements, all equipped with conducting spheres at the tip. The experiment was conducted from Hyderabad (17.5° N, 78.6° E during the post-midnight hours on 14 December 2013. In spite of a few shortcomings we report herein, a noticeable feature of the observations has been the detection of horizontal electric fields of ∼ 5 mV m−1 at the stratospheric altitudes of ∼ 35 km.

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

    Science.gov (United States)

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

    2017-09-01

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

  3. Effects of High Altitude on Sleep and Respiratory System and Theirs Adaptations

    Directory of Open Access Journals (Sweden)

    Turhan San

    2013-01-01

    Full Text Available High-altitude (HA environments have adverse effects on the normal functioning body of people accustomed to living at low altitudes because of the change in barometric pressure which causes decrease in the amount of oxygen leading to hypobaric hypoxia. Sustained exposure to hypoxia has adverse effects on body weight, muscle structure and exercise capacity, mental functioning, and sleep quality. The most important step of acclimatization is the hyperventilation which is achieved by hypoxic ventilatory response of the peripheral chemoreceptors. Hyperventilation results in increase in arterial carbondioxide concentration. Altitude also affects sleep and cardiac output, which is the other determinant of oxygen delivery. Upon initial exposure to HA, the resting pulse rate increases rapidly, but with acclimatization, heart rate and cardiac output tend to fall. Another important component that leads to decrease in cardiac output is the reduction in the stroke volume with acclimatization. During sleep at HA, the levels of CO2 in the blood can drop very low and this can switch off the drive to breathe. Only after the body senses a further drop in O2 levels breathing is started again. Periodic breathing is thought to result from instability in the control system through the hypoxic drive or the response to CO2.

  4. Evaluating the Capability of High-Altitude Infrasound Platforms to Cover Gaps in Existing Networks.

    Energy Technology Data Exchange (ETDEWEB)

    Bowman, Daniel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-09-01

    A variety of Earth surface and atmospheric sources generate low frequency sound waves that can travel great distances. Despite a rich history of ground-based sensor studies, very few experiments have investigated the prospects of free floating microphone arrays at high altitudes. However, recent initiatives have shown that such networks have very low background noise and may sample an acoustic wave field that is fundamentally different than that at the Earth's surface. The experiments have been limited to at most two stations at altitude, limiting their utility in acoustic event detection and localization. We describe the deployment of five drifting microphone stations at altitudes between 21 and 24 km above sea level. The stations detected one of two regional ground-based explosions as well as the ocean microbarom while traveling almost 500 km across the American Southwest. The explosion signal consisted of multiple arrivals; signal amplitudes did not correlate with sensor elevation or source range. A sparse network method that employed curved wave front corrections was able to determine the backazimuth from the free flying network to the acoustic source. Episodic broad band signals similar to those seen on previous flights in the same region were noted as well, but their source remains unclear. Background noise levels were commensurate with those on infrasound stations in the International Monitoring System (IMS) below 2 seconds, but sensor self noise appears to dominate at higher frequencies.

  5. Student-Built High-Altitude Balloon Payload with Sensor Array and Flight Computer

    Science.gov (United States)

    Jeffery, Russell; Slaton, William

    A payload was designed for a high-altitude weather balloon. The flight controller consisted of a Raspberry Pi running a Python 3.4 program to collect and store data. The entire payload was designed to be versatile and easy to modify so that it could be repurposed for other projects: The code was written with the expectation that more sensors and other functionality would be added later, and a Raspberry Pi was chosen as the processor because of its versatility, its active support community, and its ability to interface easily with sensors, servos, and other such hardware. For this project, extensive use was made of the Python 3.4 libraries gps3, PiCamera, and RPi.GPIO to collect data from a GPS breakout board, a Raspberry Pi camera, a geiger counter, two thermocouples, and a pressure sensor. The data collected clearly shows that pressure and temperature decrease as altitude increases, while β-radiation and γ-radiation increase as altitude increases. These trends in the data follow those predicted by theoretical calculations made for comparison. This payload was developed in such a way that future students could easily alter it to include additional sensors, biological experiments, and additional error monitoring and management. Arkansas Space Grant Consortium (ASGC) Workforce Development Grant.

  6. Living high-training low altitude training: effects on mucosal immunity.

    Science.gov (United States)

    Tiollier, E; Schmitt, L; Burnat, P; Fouillot, J-P; Robach, P; Filaire, E; Guezennec, Cy; Richalet, J-P

    2005-06-01

    Secretory immunoglobulin A (sIgA) is the major immunoglobulin of the mucosal immune system. Whereas the suppressive effect of heavy training on mucosal immunity is well documented, little is known regarding the influence of hypoxia exposure on sIgA during altitude training. This investigation examined the impact of an 18-day Living high-training low (LHTL) training camp on sIgA levels in 11 (six females and five males) elite cross-country skiers. Subjects from the control group (n=5) trained and lived at 1,200 m of altitude, whereas, subjects from the LHTL group (n=6) trained at 1,200 m, but lived at a simulated altitude of 2,500, 3,000 and 3,500 m (3x6-day, 11 h day(-1)) in hypoxic rooms. Saliva samples were collected before, after each 6-day phases and 2 weeks thereafter (POST). Salivary sIgA, protein and cortisol were measured. There was a downward trend in sIgA concentrations over the study, which reached significance in LHTL (Ptraining. Two weeks of active recovery did not allow for proper sIgA recovery. The mechanism underlying this depression of sIgA could be mediated by neural factors.

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

    Science.gov (United States)

    1994-01-01

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

  8. Comparison of Subjective Sleep Quality of Long-Term Residents at Low and High Altitudes: SARAHA Study.

    Science.gov (United States)

    Gupta, Ravi; Ulfberg, Jan; Allen, Richard P; Goel, Deepak

    2018-01-15

    To study the effect of altitude on subjective sleep quality in populations living at high and low altitudes after excluding cases of restless legs syndrome (RLS). This population-based study was conducted at three different altitudes (400 m, 1,900-2,000 m, and 3,200 m above sea level). All consenting subjects available from random stratified sampling in the Himalayan and sub-Himalayan regions of India were included in the study (ages 18 to 84 years). Sleep quality and RLS status were assessed using validated translations of Pittsburgh Sleep Quality Index (PSQI) and Cambridge Hopkins RLS diagnostic questionnaire. Recent medical records were screened to gather data for medical morbidities. In the total sample of 1,689 participants included, 55.2% were women and average age of included subjects was 35.2 (± 10.9) years. In this sample, overall 18.4% reported poor quality of sleep (PSQI ≥ 5). Poor quality of sleep was reported more commonly at high altitude compared to low altitude (odds ratio [OR] = 2.65; 95% CI = 1.9-3.7; P quality of sleep were male sex, smoking, chronic obstructive pulmonary disease (COPD), and varicose veins. Binary logistic regression indicated that COPD (OR = 1.97; 95% CI = 1.36-2.86; P quality of sleep. This study showed that poor quality of sleep was approximately twice as prevalent at high altitudes compared to low altitudes even after removing the potential confounders such as RLS and COPD.

  9. Protective effects of Astragalus-Lilygranules on intestinal mucosal barrier of mice in high altitude hypoxia

    Directory of Open Access Journals (Sweden)

    Ling LI

    2016-10-01

    Full Text Available Objective  To investigate the protective effect of Astragalus-Lily Granules on intestinal mucosa and intestinal flora homeostasis in mice under high altitude hypoxia condition. Methods  We put mice into high altitude hypoxia cabin to establish high altitude hypoxia model mice. Sixty Kunming mice were randomly divided into control group, model group, Astragalus-Lily particles (ALP low, medium and high dose groups [1.75, 3.5, 7g/(kg•d] respectively. After three days of routine feeding, the ALP mice received drug by intragastric administration, once a day for continuous 17 days,control group and model group were given double distilled water in same volume. From the 15th day, all the mice but control group were exposed to simulated high altitude hypoxia condition for 3 days in a high altitude hypoxia cabin after they were gavaged for half an hour daily. By the 18th day, the fresh mouse feces were collected and smeared to observe the changes of microflora. The pathological changes of intestinal tissues were observed by HE staining and the expression of HIF-1αprotein in intestines was detected by immunohistochemistry. Results  The enterococci and gram negative bacteria showed a higher proportion (65.2%±2.4% and 56.7%±3.3%, respectively in the model group compared with the control group (24.7%±1.2%, 23.2%±1.5%, respectively, P<0.05. The pathological score of intestinal mucosal necrosis and edema (3.10±0.99, 3.30±0.67 respectively and inflammatory cell count (15.93±3.30, 16.40±3.97/ HP respectively was higher compared with the model group (0.70±0.67, 0.80±0.78; 4.07±2.12, 4.28±2.16/HP respectively; P<0.05. HIF-1αexpression increased significantly compared with the model group (P<0.05. The enterococci (46.7%±2.0%, 32.0%±2.6% respectively and gram negative bacteria rate (34.2%±1.6%, 38.0%±2.8% respectively in the ALP medium and high dose groups were lower compared with the model group (24.7%±1.2%, 23.2%±1.5% respectively, P<0

  10. GPM GROUND VALIDATION HIGH ALTITUDE IMAGING WIND AND RAIN AIRBORNE PROFILER (HIWRAP) MC3E V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The High-Altitude Imaging Wind and Rain Airborne Profiler (HIWRAP) is a dual-frequency (Ka- and Ku-band) conical scan system, configured with a nadir viewing antenna...

  11. HURRICANE AND SEVERE STORM SENTINEL (HS3) GLOBAL HAWK HIGH ALTITUDE MMIC SOUNDING RADIOMETER (HAMSR) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The Hurricane and Severe Storm Sentinel (HS3) Global Hawk High Altitude MMIC Sounding Radiometer (HAMSR) dataset includes measurements gathered by the HAMSR...

  12. High-Altitude Airborne Platform Characterisation of Adaptive Optic Corrected Ground Based Laser

    Science.gov (United States)

    Bennet, F.; Petkovic, M.; Sheard, B.; Greene, B.

    Adaptive optics can be used for more than astronomical imaging with large telescopes. The Research School of Astronomy and Astrophysics (RSAA) and the Space Environment Management Research Centre (SERC) at the Mount Stromlo Observatory in Canberra, Australia, have been developing adaptive optics (AO) for space environment management. Turbulence in the atmosphere causes optical signals to become degraded during propagation, which reduces the effective aperture of your transmitting or receiving telescope. An AO system measures and corrects for the turbulence in the atmosphere, allowing for greater resolution of optical signals. AO can be used to correct a laser beam propagating from the ground into space, or high-altitude airborne platform. The AO system performance depends heavily on the chosen site and system design. In order to properly design and implement a cost-effective AO system to propagate a laser into orbit, we propose using high-altitude platforms to measure AO system performance directly as a precursor in-orbit measurements. SERC plan on demonstrating remote manoeuvre of an orbiting object using photon pressure from an AO corrected high power ground based laser. The manoeuvre target will be a suitable piece of debris, or a dedicated satellite mission which is instrumented and tracked to measure the applied photon pressure and resulting orbit perturbation. High-altitude airborne platforms such as weather balloons or UAVs enable us to efficiently de-risk elements of this program by validating our numerical simulations of AO system performance with actual measurements. We are then able to confidently move towards in-orbit measurement of an AO corrected ground based laser, and remote manoeuvre with photon pressure. We present simulations along with experimental results for the development of array detectors which can be used to directly measure AO system performance.

  13. Incidence and care of environmental dermatoses in the high-altitude region of Ladakh, India

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    G K Singh

    2013-01-01

    Full Text Available Background : Low humidity, high-velocity wind, excessive ultraviolet (UV exposure, and extreme cold temperature are the main causes of various types of environmental dermatoses in high altitudes. Materials and Methods: A retrospective study was carried out in patients visiting the lone dermatology department in Ladakh between July 2009 and June 2010. The aim was to identify the common environmental dermatoses in high altitudes so that they can be treated easily or prevented. The patients were divided into three demographic groups, namely, lowlanders, Ladakhis (native highlanders, and tourists. Data was analyzed in a tabulated fashion. Results: A total of 1,567 patients with skin ailments were seen, of whom 965 were lowlanders, 512 native Ladakhis, and 90 were tourists. The skin disorders due to UV rays, dry skin, and papular urticaria were common among all groups. The frequency of melasma ( n = 42; 49.4%, chronic actinic dermatitis (CAD ( n = 18; 81.81% of total CAD cases, and actinic cheilitis ( n = 3; 100% was much higher among the native Ladakhis. The frequency of cold-related injuries was much lesser among Ladakhis ( n = 1; 1.19% than lowlanders ( n = 70; 83.33% and tourists ( n = 13; 15.47% ( P < 0.05. Conclusion: Dryness of skin, tanning, acute or chronic sunburn, polymorphic light reaction, CAD, insect bite reactions, chilblain, and frostbite are common environmental dermatoses of high altitudes. Avoidance of frequent application of soap, application of adequate and suitable emollient, use of effective sunscreen, and wearing of protective clothing are important guidelines for skin care in this region.

  14. Current-use pesticide transport to Costa Rica's high-altitude tropical cloud forest.

    Science.gov (United States)

    Shunthirasingham, Chubashini; Gouin, Todd; Lei, Ying D; Ruepert, Clemens; Castillo, Luisa E; Wania, Frank

    2011-12-01

    To gain insight into the atmospheric transport and deposition of organic contaminants in high-altitude forests in the humid tropics, pesticides were analyzed in air, water, and soil samples from Costa Rica. Passive samplers deployed across the country revealed annually averaged air concentrations of chlorothalonil, endosulfan, and pendimethalin that were higher in areas with intensive agricultural activities than in more remote areas. Atmospheric concentrations were particularly high in the intensively cultivated central valley. Only endosulfan and its degradation products were found in soils sampled along an altitudinal transect on the northern side of Volcano Turrialba, which is facing heavily cultivated coastal plains. Consistent with calculations of cold trapping in tropical mountains, concentrations of endosulfan sulfate increased with altitude. Pesticide levels in lake, creek, fog, and arboreal water samples from high-elevation cloud forests were generally below 10 ng · L(-1). Endosulfan sulfate was the most abundant pesticide in water, with concentrations ranging from 0.4 to 9.4 ng · L(-1). Its levels were highest in water sampled from bromeliads. Levels of total endosulfan in water are much lower than the reported median lethal concentration (LC50) value for acute toxicity of α-endosulfan to tadpoles. Although this suggests that the presence of pesticide might not have a direct impact on amphibian populations, the possibility of effects of chronic exposure to a mixture of substances cannot be excluded. Fog was relatively enriched in some of the analyzed pesticides, such as dacthal and chlorothalonil, and may constitute an important deposition pathway to high-altitude tropical cloud forest. Copyright © 2011 SETAC.

  15. A numerical optimization of high altitude testing facility for wind tunnel experiments

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    Bruce Ralphin Rose J

    2015-06-01

    Full Text Available High altitude test facilities are required to test the high area ratio nozzles operating at the upper stages of rocket in the nozzle full flow conditions. It is typically achieved by creating the ambient pressure equal or less than the nozzle exit pressure. On average, air/GN2 is used as active gas for ejector system that is stored in the high pressure cylinders. The wind tunnel facilities are used for conducting aerodynamic simulation experiments at/under various flow velocities and operating conditions. However, constructing both of these facilities require more laboratory space and expensive instruments. Because of this demerit, a novel scheme is implemented for conducting wind tunnel experiments by using the existing infrastructure available in the high altitude testing (HAT facility. This article presents the details about the methods implemented for suitably modifying the sub-scale HAT facility to conduct wind tunnel experiments. Hence, the design of nozzle for required area ratio A/A∗, realization of test section and the optimized configuration are focused in the present analysis. Specific insights into various rocket models including high thrust cryogenic engines and their holding mechanisms to conduct wind tunnel experiments in the HAT facility are analyzed. A detailed CFD analysis is done to propose this conversion without affecting the existing functional requirements of the HAT facility.

  16. Quantification of optic disc edema during exposure to high altitude shows no correlation to acute mountain sickness.

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    Gabriel Willmann

    Full Text Available BACKGROUND: The study aimed to quantify changes of the optic nerve head (ONH during exposure to high altitude and to assess a correlation with acute mountain sickness (AMS. This work is related to the Tuebingen High Altitude Ophthalmology (THAO study. METHODOLOGY/PRINCIPAL FINDINGS: A confocal scanning laser ophthalmoscope (cSLO, Heidelberg Retina Tomograph, HRT3® was used to quantify changes at the ONH in 18 healthy participants before, during and after rapid ascent to high altitude (4559 m. Slitlamp biomicroscopy was used for clinical optic disc evaluation; AMS was assessed with Lake Louise (LL and AMS-cerebral (AMS-c scores; oxygen saturation (SpO₂ and heart rate (HR were monitored. These parameters were used to correlate with changes at the ONH. After the first night spent at high altitude, incidence of AMS was 55% and presence of clinical optic disc edema (ODE 79%. Key stereometric parameters of the HRT3® used to describe ODE (mean retinal nerve fiber layer [RNFL] thickness, RNFL cross sectional area, optic disc rim volume and maximum contour elevation changed significantly at high altitude compared to baseline (p<0.05 and were consistent with clinically described ODE. All changes were reversible in all participants after descent. There was no significant correlation between parameters of ODE and AMS, SpO₂ or HR. CONCLUSIONS/SIGNIFICANCE: Exposure to high altitude leads to reversible ODE in the majority of healthy subjects. However, these changes did not correlate with AMS or basic physiologic parameters such as SpO₂ and HR. For the first time, a quantitative approach has been used to assess these changes during acute, non-acclimatized high altitude exposure. In conclusion, ODE presents a reaction of the body to high altitude exposure unrelated to AMS.

  17. Microelement content of bone tissue in transosseous osteosynthesis by II-izarov technique in high-altitude destinations (experimental research

    OpenAIRE

    Erokhin A.N.; Isakov B.D.; Nakoskin A.N.

    2014-01-01

    Aim: To study the redistribution of microelements in bone tissue in osteosynthesis in high-altitude destinations. Material and Methods. The study was performed on 72 mongrel dogs of both sexes aged 1-3 years, weighing 10—15 kg. 32 dogs have been experienced the extended leg in lowlands destinations, another group of 32 animals have been experienced elongation produced in high-altitude destinations. The control group consisted of 8 healthy dogs of low mountain areas. The standard technique of ...

  18. Periodic breathing, arterial oxyhemoglobin saturation, and heart rate during sleep at high altitude.

    Science.gov (United States)

    Insalaco, Giuseppe; Romano, Salvatore; Salvaggio, Adriana; Pomidori, Luca; Mandolesi, Gaia; Cogo, Annalisa

    2012-12-01

    The aim of this study was to investigate the effects of acclimatization to high altitude on periodic breathing (PB), arterial oxygen saturation (Sao(2)), and heart rate (HR). Nine male elite climbers, age 24-52 years underwent overnight cardiorespiratory monitoring at sea level and at Everest North Base Camp (5180 m), during the first (BC1) and the tenth (BC2) nights. PB was commonplace in all subjects at high altitude. PB cycle duration increased (p<0.0001) from BC1 (21.7±1.9 s) to BC2 (26.7±2.1 s). Mean Sao(2) from BC1 to BC2, significantly increased during wakefulness (77.4±3.4% vs. 82.5±2.8%; p<0.001) and during sleep regular breathing (73.3±3.8% vs. 77.8±2.9%; p=0.022). During PB, mean higher Sao(2) was 75.3±3.6% at BC1 and 82.4±2.9% at BC2 (p<0.001); mean lower Sao(2) was 68.2±4.0% at BC1 and 74.5±4.3% at BC2 (p<0.01). During PB, mean higher HR was 72.4±8.8 b/min at BC1 and 63.3±6.0 b/min at BC2 (p<0.0002); mean lower HR were 53.6±7.5% at BC1 and 43.6±7.3% at BC2 (p<0.0001). The mean Sao(2) during PB compared with Sao(2) at night without PB was unchanged. Acclimatization to high altitude resulted in an overall increase in Sao(2) along with an increase in the PB cycle duration and a decrease in HR.

  19. Hemoglobin-oxygen affinity in high-altitude vertebrates: is there evidence for an adaptive trend?

    Science.gov (United States)

    Storz, Jay F

    2016-10-15

    In air-breathing vertebrates at high altitude, fine-tuned adjustments in hemoglobin (Hb)-O2 affinity provide an energetically efficient means of mitigating the effects of arterial hypoxemia. However, it is not always clear whether an increased or decreased Hb-O2 affinity should be expected to improve tissue O2 delivery under different degrees of hypoxia, due to the inherent trade-off between arterial O2 loading and peripheral O2 unloading. Theoretical results indicate that the optimal Hb-O2 affinity varies as a non-linear function of environmental O2 availability, and the threshold elevation at which an increased Hb-O2 affinity becomes advantageous depends on the magnitude of diffusion limitation (the extent to which O2 equilibration at the blood-gas interface is limited by the kinetics of O2 exchange). This body of theory provides a framework for interpreting the possible adaptive significance of evolved changes in Hb-O2 affinity in vertebrates that have colonized high-altitude environments. To evaluate the evidence for an empirical generalization and to test theoretical predictions, I synthesized comparative data in a phylogenetic framework to assess the strength of the relationship between Hb-O2 affinity and native elevation in mammals and birds. Evidence for a general trend in mammals is equivocal, but there is a remarkably strong positive relationship between Hb-O2 affinity and native elevation in birds. Evolved changes in Hb function in high-altitude birds provide one of the most compelling examples of convergent biochemical adaptation in vertebrates. © 2016. Published by The Company of Biologists Ltd.

  20. Analysis of mitochondrial DNA in Tibetan gastric cancer patients at high altitude.

    Science.gov (United States)

    Jiang, Jun; Zhao, Jun-Hui; Wang, Xue-Lian; DI, J I; Liu, Zhi-Bo; Li, Guo-Yuan; Wang, Miao-Zhou; Li, Yan; Chen, Rong; Ge, Ri-Li

    2015-07-01

    The highest risk areas of gastric cancer are currently Japan, Korea and China; Qinghai, a high-altitude area, has one of the highest gastric cancer rates in China. The incidence of gastric cancer is higher in the Tibetan ethnic group compared to that in the Han ethnic group in Qinghai. This study was conducted to determine the clinical characteristics of mitochondrial DNA (mtDNA) mutations and copy numbers among Tibetans with gastric cancer residing at high altitudes and investigate the association between adaptations to hypoxic conditions and oncogenesis. A total of 23 Tibetan gastric cancer patients and 40 matched controls were recruited in this study. Leukocyte mtDNA genes and copy numbers were analyzed. The haplogroups were classified based on mitochondrial gene sequences. A total of 56.5% of the study participants had used alcohol at some point in their lives and 73.9% were positive for Helicobacter pylori (H. pylori). Eight mutations in 8 mitochondrial genes were identified in 43.4% of the Tibetan cancer patient group. There were no significant differences in leukocyte mtDNA copy number levels based on smoking status, alchohol consumption, obesity or H. pylori infection between the control and cancer groups. Statistical differences were also not found between gastric cancer patients with and those without mtDNA mutations. The majority of Tibetan patients with gastric cancer belonged to the mitochondrial haplogroup M9. In conclusion, Tibetans with gastric cancer residing at high altitudes exhibited a wide spectrum of mtDNA mutations. However, leukocyte mtDNA copy numbers in stage II gastric cancer were not statistically different compared to those in healthy Tibetans.

  1. Optic Nerve Sheath Diameter Increase on Ascent to High Altitude: Correlation With Acute Mountain Sickness.

    Science.gov (United States)

    Kanaan, Nicholas C; Lipman, Grant S; Constance, Benjamin B; Holck, Peter S; Preuss, James F; Williams, Sarah R

    2015-09-01

    Elevated optic nerve sheath diameter on sonography is known to correlate with increased intracranial pressure and is observed in acute mountain sickness. This study aimed to determine whether optic nerve sheath diameter changes on ascent to high altitude are associated with acute mountain sickness incidence. Eighty-six healthy adults enrolled at 1240 m (4100 ft), drove to 3545 m (11,700 ft) and then hiked to and slept at 3810 m (12,500 ft). Lake Louise Questionnaire scores and optic nerve sheath diameter measurements were taken before, the evening of, and the morning after ascent. The incidence of acute mountain sickness was 55.8%, with a mean Lake Louise Questionnaire score ± SD of 3.81 ± 2.5. The mean maximum optic nerve sheath diameter increased on ascent from 5.58 ± 0.79 to 6.13 ± 0.73 mm, a difference of 0.91 ± 0.55 mm (P = .09). Optic nerve sheath diameter increased at high altitude regardless of acute mountain sickness diagnosis; however, compared to baseline values, we observed a significant increase in diameter only in those with a diagnosis of acute mountain sickness (0.57 ± 0.77 versus 0.21 ± 0.76 mm; P = .04). This change from baseline, or Δ optic nerve sheath diameter, was associated with twice the odds of developing acute mountain sickness (95% confidence interval, 1.08-3.93). The mean optic nerve sheath diameter increased on ascent to high altitude compared to baseline values, but not to a statistically significant degree. The magnitude of the observed Δ optic nerve sheath diameter was positively associated with acute mountain sickness diagnosis. No such significant association was found between acute mountain sickness and diameter elevation above standard cutoff values, limiting the utility of sonography as a diagnostic tool. © 2015 by the American Institute of Ultrasound in Medicine.

  2. Implementation of a Novel Flight Tracking and Recovery Package for High Altitude Ballooning Missions

    Science.gov (United States)

    Fatima, Aqsa; Nekkanti, Sanjay; Mohan Suri, Ram; Shankar, Divya; Prasad Nagendra, Narayan

    High altitude ballooning is typically used for scientific missions including stratospheric observations, aerological observations, and near space environment technology demonstration. The usage of stratospheric balloons is a cost effective method to pursue several scientific and technological avenues against using satellites in the void of space. Based on the Indian Institute of Astrophysics (IIA) ballooning program for studying Comet ISON using high altitude ballooning, a cost effective flight tracking and recovery package for ballooning missions has been developed using open source hardware. The flight tracking and recovery package is based on using Automatic Packet Reporting System (APRS) and has a redundant Global System for Mobile Communications (GSM) based Global Positioning System (GPS) tracker. The APRS based tracker uses AX.25 protocol for transmission of the GPS coordinates (latitude, longitude, altitude, time) alongside the heading and health parameters of the board (voltage, temperature). APRS uses amateur radio frequencies where data is transmitted in packet messaging format, modulated by radio signals. The receiver uses Very High Frequency (VHF) transceiver to demodulate the APRS signals. The data received will be decoded using MixW (open source software). A bridge will be established between the decoding software and the APRS software. The flight path will be predicted before the launch and the real time position co-ordinates will be used to obtain the real time flight path that will be uploaded online using the bridge connection. We also use open source APRS software to decode and Google Earth to display the real time flight path. Several ballooning campaigns do not employ payload data transmission in real time, which makes the flight tracking and package recovery vital for data collection and recovery of flight instruments. The flight tracking and recovery package implemented in our missions allow independent development of the payload package

  3. Acclimation to hypoxia increases carbohydrate use during exercise in high-altitude deer mice.

    Science.gov (United States)

    Lau, Daphne S; Connaty, Alex D; Mahalingam, Sajeni; Wall, Nastashya; Cheviron, Zachary A; Storz, Jay F; Scott, Graham R; McClelland, Grant B

    2017-03-01

    The low O2 experienced at high altitude is a significant challenge to effective aerobic locomotion, as it requires sustained tissue O2 delivery in addition to the appropriate allocation of metabolic substrates. Here, we tested whether high- and low-altitude deer mice (Peromyscus maniculatus) have evolved different acclimation responses to hypoxia with respect to muscle metabolism and fuel use during submaximal exercise. Using F1 generation high- and low-altitude deer mice that were born and raised in common conditions, we assessed 1) fuel use during exercise, 2) metabolic enzyme activities, and 3) gene expression for key transporters and enzymes in the gastrocnemius. After hypoxia acclimation, highland mice showed a significant increase in carbohydrate oxidation and higher relative reliance on this fuel during exercise at 75% maximal O2 consumption. Compared with lowland mice, highland mice had consistently higher activities of oxidative and fatty acid oxidation enzymes in the gastrocnemius. In contrast, only after hypoxia acclimation did activities of hexokinase increase significantly in the muscle of highland mice to levels greater than lowland mice. Highland mice also responded to acclimation with increases in muscle gene expression for hexokinase 1 and 2 genes, whereas both populations increased mRNA expression for glucose transporters. Changes in skeletal muscle with acclimation suggest that highland mice had an increased capacity for the uptake and oxidation of circulatory glucose. Our results demonstrate that highland mice have evolved a distinct mode of hypoxia acclimation that involves an increase in carbohydrate use during exercise. Copyright © 2017 the American Physiological Society.

  4. Extremophiles: photosynthetic systems in a high-altitude saline basin (Altiplano, Chile

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    Alejandro Angel

    2016-03-01

    Full Text Available Abstract Studies of different hypersaline systems have revealed various types of limitation. We evaluated the phototrophic microbial assemblages over a whole seasonal cycle (wet vs dry in the Salar de Alconcha, a high-altitude (4250 m altitude saline basin. Phototrophic microbial communities were obtained from contrasting ecotypes, and examined for the effects of proximity and salinity variations. We also analyzed pigment profiles pointing to photosynthetic activity. While taxonomic diversity was limited to three algal groups (chlorophytes, diatoms, and cyanobacteria ecological preferences were highly variable. Physical limitations when the photosynthetic system turn drier (maintaining viability and stability appear to be the most successful adaptation (constrained assemblages to the extreme condition in the Altiplano. This suggests that phototrophic microorganisms rarely achieve optimal growth, and could only do so when rain events reduce salinity (e.g. austral summer. However, environmental condition over the salt crust (total salt concentration: 119.74 g l−1 was an important driver to algal biomass. Overall, dominated by Dunaliella salina (≈18,000 cell ml−1 turning the water into a red–orange colored system (β-carotene; aplanospore cysts were observed only during the driest season (austral winter. Our results suggest specific restrictive environments (e.g. environmental dissimilarity in the physical landscape for phototrophic microbial colonization in high-altitude saline systems quite dependent upon water availability (system on the edge. The present study is a contribution for a better understanding of both the ecology of extreme environments and polyextremophiles communities (phototrophs that inhabit them. Active salars are considered to be useful analogs of ancient photosynthetic systems, currently very pressured by groundwater extraction. Thus, altering the volume of water through the basin would have negative consequences

  5. First Cluster results of the magnetic field structure of the mid- and high-altitude cusps

    Directory of Open Access Journals (Sweden)

    P. J. Cargill

    Full Text Available Magnetic field measurements from the four Cluster spacecraft from the mid- and high-altitude cusp are presented. Cluster underwent two encounters with the mid-altitude cusp during its commissioning phase (24 August 2000. Evidence for field-aligned currents (FACs was seen in the data from all three operating spacecraft from northern and southern cusps. The extent of the FACs was of the order of 1 RE in the X-direction, and at least 300 km in the Y-direction. However, fine-scale field structures with scales of the order of the spacecraft separation (300 km were observed within the FACs. In the northern crossing, two of the spacecraft appeared to lie along the same magnetic field line, and observed very well matched signals. However, the third spacecraft showed evidence for structuring transverse to the field on scales of a few hundred km. A crossing of the high-altitude cusp from 13 February 2001 is presented. It is revealed to be a highly dynamic structure with the boundaries moving with velocities ranging from a few km/s to tens of km/s, and having structure on timescales ranging from less than one minute up to several minutes. The cusp proper is associated with the presence of a very disordered magnetic field, which is entirely different from the magnetosheath turbulence.

    Key words. Magnetospheric physics (current systems; magnetopause, cusp, and boundary layers – Space plasma physics (discontinuities

  6. Simulating very high altitudes during static firings of motors at CAEPE

    Science.gov (United States)

    Heiligenstein, R.; Sauvel, J.; Daubin, J. M.; Delery, J.; Reijasse, P.

    1992-07-01

    A novel supersonic ejector cell has been developed for the study of missile radiative signatures in simulated high altitude conditions. Base pressure in the cell has been predicted according to the specific features of the rocket motor in question; the free volume of the cell was optimized to achieve a rapid evacuation of the nitrogen filling the volume prior to test firing. The distance between the nozzle exit and the impingement area in the exhaust ejectors was studied in order to maximize the radiative measurement device-observable portion of the exhaust stream. Two new test cells were built on the basis of this study's configuration.

  7. Prevalence of dermatologic diseases in school children of a high altitude tribunal area of Himachal Pradesh

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    N L Sharma

    1990-01-01

    Full Text Available A total of 201 school children,belonging to a high altitude tribal area were examined for various dermatologic lesions including nevi. All the children were found to have one or more type of diseases/lesions. Pediculosis ea tis was the comtnonest disease (74.1%, followed by pityriasis simplex (33.3%, warts (20.4%, scabies (12.9%, pyoderma (8.5% and papular urticaria (7.5%, Nevi were observed in 73.1% children. An acral erythfma associated with cold hands and feet was seen in 7.5% children.

  8. A Novel Beamforming Technique for Highways Coverage Using High-Altitude Platforms

    Directory of Open Access Journals (Sweden)

    Yasser Albagory

    2007-01-01

    Full Text Available This paper proposes a novel beamforming technique to form an arbitrary-shaped cell for the high-altitude platforms (HAPs mobile communications. The new technique is based on pattern summation of individual low-sidelobe, narrow beams which constitute the desired cell pattern weighted by an amplitude correcting function. The new cell pattern can be adapted to cover the main highways forming worm-shaped cells which may cover the highway for long distances up to 100 km and it will have an important role in reducing frequent handoffs and signaling traffic of location updating from moving users over the long highways.

  9. Corneal Opacity in a Participant of a 161-km Mountain Bike Race at High Altitude.

    Science.gov (United States)

    Khodaee, Morteza; Torres, David R

    2016-06-01

    Visual dysfunction is a relatively uncommon complaint among athletes during ultraendurance races. The pathophysiology of most of these cases is unknown. Corneal opacity has been speculated as the etiology for most of reported cases. We are presenting a case of a 56-year-old man with a partial unilateral corneal opacity and edema at kilometer 150 of a 161-km mountain bike race in high altitude. He was not able to finish the race (12-hour cutoff) because of his visual symptoms. He completely recovered in 3 days with no sequelae. Copyright © 2016 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

  10. NUCLEOTIDE COMPARISON OF GDF9 GENE IN INDIAN YAK AND GADDI GOAT: HIGH ALTITUDE LIVESTOCK ANIMALS

    Directory of Open Access Journals (Sweden)

    Lakshya Veer Singh

    2013-06-01

    Full Text Available The present study was undertaken to characterize exon 1 and exon 2 sequence of one of fecundity genes: GDF9 (Growth differentiation factor 9, in high altitude livestock animal (Yak and Gaddi goat. Six nucleotide differences were identified between sheep (AF078545 and goats (EF446168 in exon 1 and exon 2. Sequencing revealed nine novel single nucleotide mutations in exon 1 and exon 2 of Indian yak that compared with Bos taurus (GQ922451. These results preliminarily showed that the GDF9 gene might be a major gene that influences prolificacy of Gaddi goats and Indian yak.

  11. Propulsion/airframe integration considerations for high altitude hypersonic cruise vehicles

    Science.gov (United States)

    Weidner, J. P.

    1980-01-01

    A study has been conducted to determine the implications of top-mounted inlet nacelles on propulsion performance and cruise range. The top-mounted nacelle would be less visible from ground-based radar below and ahead of the aircraft. For this study, the nacelle is integrated with a high altitude Mach 5 turbojet/ramjet-powered airplane concept requiring a large nacelle. Results of the study suggest nacelle installation advantages and improved inlet mass flow ratio for the top-mounted nacelle, but at the expense of a higher installed drag at transonic and supersonic speeds.

  12. Pulmonary vascular responsiveness in rats following neonatal exposure to high altitude or carbon monoxide

    Energy Technology Data Exchange (ETDEWEB)

    Tucker, A.; Penney, D.G. (Colorado State Univ., Fort Collins, CO (United States) Wayne State Univ., Detroit, MI (United States))

    1993-01-01

    Exposure of adult and neonatal rats to high altitude increases pulmonary vascular responsiveness during the exposure. A study was undertaken to determine if a short exposure of neonatal rats to either high-altitude or carbon monoxide (CO) hypoxia would cause persistent alterations in pulmonary vascular responsiveness postexposure. One-day-old male Sprague-Dawley rats were obtained as 16 litters of 10-12 pups each. At 2 days of age, 4 litters were exposed to CO (500 ppm) for 32 days, and 4 litters were exposed to ambient air (AIR) in Detroit (200 m). Another 4 litters were exposed to 3500 m altitude (ALT) in a chamber for 32 days, and 3 litters were exposed to ambient conditions in Fort Collins (CON, 1524 m). After the exposures, all rats were maintained at 1524 m. At 2, 40, 76 and 112 days postexposure, lungs were isolated and perfused with Earle's salt solution (+Ficoll, 4 g%). Pulmonary vascular responsiveness was assessed by dose responses to angiotensin II (AII, 0.025-0.40 [mu]g) and acute hypoxia (3% O[sub 2] for 3 min). AII responses were higher in ALT vs CON rats at 2 and 40 days postexposure, but no differences were noted between CO and AIR rats. Baseline pulmonary vascular resistance and pulmonary arterial pressure (in isolated lungs) were higher in ALT rats at all four ages compared to the other three groups. Both the ALT and CO rats displayed hypertrophy of the right ventricle (RV) and the left ventricle (LV) at the termination of treatment and elevated hematocrit. LV hypertrophy and polycythemia regressed with time, but RV hypertrophy remained significant in the ALT rats through 112 days postexposure. The results indicate that neonatal exposure to ALT, but no CO, causes a persistent increase in pulmonary vascular responsiveness and RV hypertrophy for at least 112 days after termination of the exposure. 40 refs., 3 figs., 2 tabs.

  13. Establishment of extracorporeal circulation of artificial liver support system in high altitude region

    Directory of Open Access Journals (Sweden)

    Ming-sen ZHANG

    2011-01-01

    Full Text Available Objective To establish extracorporeal circulation in big animal suitable for the research on artificial liver support system in high altitude region.Methods Under the anesthesia of ketamine hydrochloride/diazepam IV,cannulation of common carotid artery/external jugular vein(n=3 and inferior vena cava via the left external jugular vein/right external jugular vein(n=3,was respectively performed on six healthy Chang-Bai piglets adapted to native environment(altitude 3700m.One day after that,the extracorporeal circulation was performed at a progressively elevated blood current velocity,and the general condition of the animals,blood pressure,HR,bleeding tendoncy of the experimental pigs and coagulation in the cannulae were observed.Results On the premise that the hemodynamics was not influenced,the highest blood current velocity was 133.33±28.87ml/min,the lowest heparin maintaining speed amounted to 138.67±12.22mg/h,and the bleeding tendency and blood coagulation in the cannula was significant in the group of common carotid artery/external jugular vein intubation.While the highest blood current velocity was 400ml/min,the lowest heparin maintaining speed was 26.67±9.24mg/h,no bleeding tendency or obvious cannular blood coagulation were observed in the group of cannulation of inferior vena cava via the left external jugular vein/right external jugular vein.These untoward results were significantly less or slight than that of the former group(P < 0.01.Conclusion It is suitable to perform research of artificial liver support system on piglets in high altitude region by establishing extracorporeal circulation by the way of inferior vena cava with cannulation passing through the left external jugular vein/right external jugular vein with the blood current velocity of 400ml/min.

  14. Analysis of High-altitude Syndrome and the Underlying Gene Polymorphisms Associated with Acute Mountain Sickness after a Rapid Ascent to High-altitude

    Science.gov (United States)

    Yu, Jie; Zeng, Ying; Chen, Guozhu; Bian, Shizhu; Qiu, Youzhu; Liu, Xi; Xu, Baida; Song, Pan; Zhang, Jihang; Qin, Jun; Huang, Lan

    2016-12-01

    To investigated the objective indicators and potential genotypes for acute mountain sickness (AMS). 176 male subjects were evaluated for symptoms scores and physiological parameters at 3700 m. EPAS1 gene polymorphisms were explored and verified effects of potential genotypes on pulmonary function by inhaled budesonide. The incidence of AMS was 53.98% (95/176). The individuals who suffered from headache with anxiety and greater changes in heart rate (HR), the forced vital capacity (FVC), and mean flow velocity of basilar artery (Vm-BA), all of which were likely to develop AMS. The rs4953348 polymorphism of EPAS1 gene had a significant correlation with the SaO2 level and AMS, and a significant difference in the AG and GG genotype distribution between the AMS and non-AMS groups. The spirometric parameters were significantly lower, but HR (P = 0.036) and Vm-BA (P = 0.042) significantly higher in the AMS subjects with the G allele than those with the A allele. In summary, changes in HR (≥82 beats/min), FVC (≤4.2 Lt) and Vm-BA (≥43 cm/s) levels may serve as predictors for diagnosing AMS accompanied by high-altitude syndrome. The A allele of rs4953348 is a protective factor for AMS through HR and Vm-BA compensation, while the G allele may contribute to hypoxic pulmonary hypertension in AMS.

  15. Inquiry-Based Early Undergraduate Research Using High-Altitude Ballooning

    Science.gov (United States)

    Sibbernsen, K.; Sibbernsen, M.

    2012-12-01

    One common objective for undergraduate science classes is to have students learn how to do scientific inquiry. However, often in science laboratory classes, students learn to take data, analyze the data, and come to conclusions, but they are told what to study and do not have the opportunity to ask their own research questions, a crucial part of scientific inquiry. A special topics class in high-altitude ballooning (HAB) was offered at Metropolitan Community College, a large metropolitan two-year college in Omaha, Nebraska to focus on scientific inquiry for the participants through support of NASA Nebraska Space Grant. A weather balloon with payloads attached (balloonSAT) was launched to near space where the balloon burst and fell back to the ground with a parachute. Students worked in small groups to ask their research questions, they designed their payloads, participated in the launch and retrieval of equipment, analyzed data, and presented the results of their research. This type of experience has potential uses in physics, physical science, engineering, electronics, computer programming, meteorology, astronomy, and chemistry classes. The balloonSAT experience can act as a stepping-stone to designing sounding rocket payloads and it can allow students the opportunity to participate in regional competitions and present at HAB conferences. Results from the workshop are shared, as well as student responses to the experience and suggestions for administering a high-altitude ballooning program for undergraduates or extending inquiry-based ballooning experiences into high-school or middle-school.

  16. The impact of high altitude aircraft on the ozone layer in the stratosphere

    Science.gov (United States)

    Tie, Xue XI; Brasseur, Guy; Lin, Xing; Friedlingstein, P.; Granier, Claire; Rasch, Philip

    1994-01-01

    The paper discusses the potential effects on the ozone layer of gases released by the engines of proposed high altitude supersonic aircraft. The major problem arises from the emissions of nitrogen oxides which have the potential to destroy significant quantities of ozone in the stratosphere. The magnitude of the perturbation is highly dependent on the cruise altitude of the aircraft. Furthermore, the depletion of ozone is substantially reduced when heterogeneous conversion of nitrogen oxides into nitric acid on sulfate aerosol particles is taken into account in the calculation. The sensitivity of the aerosol load on stratospheric ozone is investigated. First, the model indicates that the aerosol load induced by the SO2 released by aircraft is increased by about 10-20% above the background aerosols at mid-high latitude of the Northern Hemisphere at 15 km for the NASA emission scenario A (the NASA emission scenarios are explained in Tables I to III). This increase in aerosol has small effects on stratospheric ozone. Second, when the aerosol load is increased following a volcanic eruption similar to the eruption of El Chichon (Mexico, April 1982), the ozone column in spring increases by as much as 9% in response to the injection of NOx from the aircraft with the NASA emission scenario A. Finally, the modeled suggests that significant ozone depletion could result from the formation of additional polar stratospheric clouds produced by the injection of H2O and HNO3 by the aircraft engines.

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

    Science.gov (United States)

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

    2014-09-01

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

  18. Cone structure and focusing of VLF and LF electromagnetic waves at high altitudes in the ionosphere

    Science.gov (United States)

    Alpert, Ya. L.; Green, J. L.

    1994-01-01

    The frequency and angle dependencies of the electric field radiated by an electric dipole E = E(sub 0) cos omega(t) are studied through numerical calculations of absolute value of E in the VLF and LF frequency bands where F is less than or equal 0.02 to 0.05 f(sub b) in a model ionosphere over an altitude region of 800-6000 km where the wave frequency and electron gyrofrequency varies between F approximately 4-500 kHz and f(sub b) is approximately equal (1.1 to 0.2) MHz respectively. It is found that the amplitudes of the electric field have large maxima in four regions: close to the direction of the Earth magnetic field line B(sub 0) (it is called the axis field E(sub 0), in the Storey E(sub St), reversed Storey E(sub RevSt), and resonance E(sub Res) cones. The maximal values of E(sub 0), E(sub Res), and E(sub RevSt) are the most pronounced close to the lower hybrid frequency, F approximately F(sub L). The flux of the electric field is concentrated in very narrow regions, with the apex angles of the cones Delta-B is approximately (0.1-1) deg. The enhancement and focusing of the electric field increases with altitude starting at Z greater than 800 km. At Z greater than or equal to 1000 up to 6000 km, the relative value of absolute value of E, in comparison with its value at Z = 800 km is about (10(exp 2) to 10(exp 4)) times larger. Thus the flux of VLF and LF electromagnetic waves generated at high altitudes in the Earth's ionosphere are trapped into very narrow conical beams similar to laser beams.

  19. Atmospheric transport of neutrons and gamma rays from a high-altitude nuclear detonation

    Energy Technology Data Exchange (ETDEWEB)

    Byrd, R.C.

    1995-07-01

    Although radiation outputs from nuclear detonations in free space are well established, few studies exist of effect of atmospheric transport on the resulting intensity, energy, and time signatures. This report presents calculations for generic sources at high altitudes, 20-50 km above the Earth`s surface, in an atmosphere whose density decreases almost exponentially with height. The sources are instantaneous time bursts with simple energy dependences: gamma rays use an evaporation spectrum; neutrons use either a Gaussian fusion or a Maxwell fission spectrum. The observation angles vary from vertical to 5{degrees} below the horizon, and detectors are placed in either geosynchronous or low Earth orbits (100 km). All calculations use the Monte Carlo N-Particle (MCNP) transport code in either its photon, neutron, or coupled neutron-photon modes, with the coupled mode being applied to the production of gamma rays by neutron inelastic scattering. The standard MCNP outputs are analyzed to extract the intensity, energy, and time dependences of the fluence as functions of either source altitude or observation angle. In general, the intensities drop rapidly below about 30-km source altitude or +5` slant angle. Above these limits, the gamma-ray signal loses substantial intensity but still contains most of the original source information. In contrast, neutron scattering produces little or no decrease in intensity, but it rapidly degrades much of the information about the original source spectrum. Finally, although there is abundant gamma-ray production from neutron inelastic scattering, the resulting signatures appear to provide little additional information.

  20. The effect of drinking tea at high altitude on hydration status and mood.

    Science.gov (United States)

    Scott, David; Rycroft, Jane A; Aspen, Jennifer; Chapman, Clare; Brown, Bryce

    2004-04-01

    The effect of drinking tea on hydration status and mood was studied in nine male and four female members of expeditions based at Mt. Everest base camp at an altitude of 5,345 m. Whilst exposed to altitude-cold diuresis, participants were subjected to a crossover experimental design comprising two 24-h dietary interventions. In the "tea" condition, hot brewed tea formed a major part of fluid intake, whereas in the "no-tea" condition tea was excluded from the diet. Subjects were prohibited in both cases from consuming other caffeinated beverages, caffeinated foods, and alcoholic drinks. Mean fluids ingested [mean (SE); tea=3,193 (259) ml versus no tea=3,108 (269) ml] and urine volume (tea=2,686 (276) ml versus no tea=2,625 (342) ml] were similar under both conditions. Statistical analysis found no difference in urine stimulated as a result of the tea intervention (P=0.81). Several markers of hydration status were also taken immediately pre and post each condition, including measures of urine specific gravity, urine electrolyte balance (K+, Na+), and urine colour. None of these measures indicated a difference in hydration status as a result of the dietary intervention in either the control or tea condition. A difference was, however, found in mood, with subjects reporting reduced fatigue when tea was included in the diet (P=0.005). The study shows therefore that even when drunk at high altitude where fluid balance is stressed, there is no evidence that tea acts as a diuretic when consumed through natural routes of ingestion by regular tea drinkers, but that it does have a positive effect on mood.

  1. Shared Genetic Signals of Hypoxia Adaptation in Drosophila and in High-Altitude Human Populations

    Science.gov (United States)

    Jha, Aashish R.; Zhou, Dan; Brown, Christopher D.; Kreitman, Martin; Haddad, Gabriel G.; White, Kevin P.

    2016-01-01

    The ability to withstand low oxygen (hypoxia tolerance) is a polygenic and mechanistically conserved trait that has important implications for both human health and evolution. However, little is known about the diversity of genetic mechanisms involved in hypoxia adaptation in evolving populations. We used experimental evolution and whole-genome sequencing in Drosophila melanogaster to investigate the role of natural variation in adaptation to hypoxia. Using a generalized linear mixed model we identified significant allele frequency differences between three independently evolved hypoxia-tolerant populations and normoxic control populations for approximately 3,800 single nucleotide polymorphisms. Around 50% of these variants are clustered in 66 distinct genomic regions. These regions contain genes that are differentially expressed between hypoxia-tolerant and normoxic populations and several of the differentially expressed genes are associated with metabolic processes. Additional genes associated with respiratory and open tracheal system development also show evidence of directional selection. RNAi-mediated knockdown of several candidate genes’ expression significantly enhanced survival in severe hypoxia. Using genomewide single nucleotide polymorphism data from four high-altitude human populations—Sherpas, Tibetans, Ethiopians, and Andeans, we found that several human orthologs of the genes under selection in flies are also likely under positive selection in all four high-altitude human populations. Thus, our results indicate that selection for hypoxia tolerance can act on standing genetic variation in similar genes and pathways present in organisms diverged by hundreds of millions of years. PMID:26576852

  2. Interaction between the low altitude atmosphere and clouds by high-precision polarization lidar

    Science.gov (United States)

    Shiina, Tatsuo; Noguchi, Kazuo; Fukuchi, Tetsuo

    2012-11-01

    Lidar is a powerful remote sensing tool to monitor the weather changes and the environmental issues. This technique should not been restricted in those fields. In this study, the authors aim to be apply it to the prediction of weather disaster. The heavy rain and the lightning strike are our targets. The inline typed MPL (micro pulse lidar) has been accomplished to grasp the interaction between the low altitude cloud and the atmosphere and to predict the heavy rain, while it was hard to catch the sign of lightning strike. The authors introduced a new algorism to catch the direct sign of the lightning strike. Faraday effect is caused by lightning discharge in the ionized atmosphere. This effect interacts with the polarization of the propagating beam, that is, the polarization plane is rotated by the effect. In this study, high precision polarization lidar was developed to grasp the small rotation angle of the polarization of the propagating beam. In this report, the interaction between the low altitude cloud and the atmosphere was monitored by the high precision polarization lidar. And the observation result of the lightning discharge were analyzed.

  3. Cooperative Scheduling of Imaging Observation Tasks for High-Altitude Airships Based on Propagation Algorithm

    Directory of Open Access Journals (Sweden)

    He Chuan

    2012-01-01

    Full Text Available The cooperative scheduling problem on high-altitude airships for imaging observation tasks is discussed. A constraint programming model is established by analyzing the main constraints, which takes the maximum task benefit and the minimum cruising distance as two optimization objectives. The cooperative scheduling problem of high-altitude airships is converted into a main problem and a subproblem by adopting hierarchy architecture. The solution to the main problem can construct the preliminary matching between tasks and observation resource in order to reduce the search space of the original problem. Furthermore, the solution to the sub-problem can detect the key nodes that each airship needs to fly through in sequence, so as to get the cruising path. Firstly, the task set is divided by using k-core neighborhood growth cluster algorithm (K-NGCA. Then, a novel swarm intelligence algorithm named propagation algorithm (PA is combined with the key node search algorithm (KNSA to optimize the cruising path of each airship and determine the execution time interval of each task. Meanwhile, this paper also provides the realization approach of the above algorithm and especially makes a detailed introduction on the encoding rules, search models, and propagation mechanism of the PA. Finally, the application results and comparison analysis show the proposed models and algorithms are effective and feasible.

  4. PAIN THRESHOLD MEASUREMENTS IN HIGH AND LOW ALTITUDE AMONG HEALTHY VOLUNTEER ADULTS: A COMPARATIVE STUDY

    Directory of Open Access Journals (Sweden)

    Nashwa S. Hamed

    2016-12-01

    Full Text Available Background: Majority of high altitude residents have certain clinical, physiological, anatomical and biochemical changes. Pain threshold is one of the numerable changes that may occur due to chronic hypoxia. The aim of this research was to study the long term effects of high altitude exposure on pain perception among healthy volunteer subjects. Methods: This is an observational case-control study. Two groups of healthy volunteer subjects, highland group (n=242 and lowland group (n=242 in two different cities. Assessment methods used were: Pressure algometer, was measured bilaterally three times on ten body points and Situational pain scale, which is 18 items self-report questionnaire measuring the mental representation of pain intensity in imaginary painful situations. Results: pain sensitivity was lower in highlanders compared to lowlanders (p<0.0005. While the participants’ attitudes towards imaginary painful situations trough SPS showed lesser pain sensitivity in highlanders compared to lowlanders in 72% from the total scale items. Conclusion: According to the results of the current study, pressure pain threshold is higher (pain sensitivity is lower in highlanders compared to lowlanders. And attitudes towards imaginary painful situations are lower in highland population compared to lowland population as a long-term effect of chronic hypoxia.

  5. Serum testosterone levels and excessive erythrocytosis during the process of adaptation to high altitudes

    Science.gov (United States)

    Gonzales, Gustavo F

    2013-01-01

    Populations living at high altitudes (HAs), particularly in the Peruvian Andes, are characterized by a mixture of subjects with erythrocytosis (16 g dl−121 g dl−1). Elevated haemoglobin values (EE) are associated with chronic mountain sickness, a condition reflecting the lack of adaptation to HA. According to current data, native men from regions of HA are not adequately adapted to live at such altitudes if they have elevated serum testosterone levels. This seems to be due to an increased conversion of dehydroepiandrosterone sulphate (DHEAS) to testosterone. Men with erythrocytosis at HAs show higher serum androstenedione levels and a lower testosterone/androstenedione ratio than men with EE, suggesting reduced 17beta-hydroxysteroid dehydrogenase (17beta-HSD) activity. Lower 17beta-HSD activity via Δ4-steroid production in men with erythrocytosis at HA may protect against elevated serum testosterone levels, thus preventing EE. The higher conversion of DHEAS to testosterone in subjects with EE indicates increased 17beta-HSD activity via the Δ5-pathway. Currently, there are various situations in which people live (human biodiversity) with low or high haemoglobin levels at HA. Antiquity could be an important adaptation component for life at HA, and testosterone seems to participate in this process. PMID:23524530

  6. High altitude hypoxia as a factor that promotes tibial growth plate development in broiler chickens.

    Science.gov (United States)

    Huang, Shucheng; Zhang, Lihong; Rehman, Mujeeb Ur; Iqbal, Muhammad Kashif; Lan, Yanfang; Mehmood, Khalid; Zhang, Hui; Qiu, Gang; Nabi, Fazul; Yao, Wangyuan; Wang, Meng; Li, Jiakui

    2017-01-01

    Tibial dyschondroplasia (TD) is one of the most common problems in the poultry industry and leads to lameness by affecting the proximal growth plate of the tibia. However, due to the unique environmental and geographical conditions of Tibet, no case of TD has been reported in Tibetan chickens (TBCs). The present study was designed to investigate the effect of high altitude hypoxia on blood parameters and tibial growth plate development in chickens using the complete blood count, morphology, and histological examination. The results of this study showed an undesirable impact on the overall performance, body weight, and mortality of Arbor Acres chickens (AACs) exposed to a high altitude hypoxic environment. However, AACs raised under hypoxic conditions showed an elevated number of red blood cells (RBCs) and an increase in hemoglobin and hematocrit values on day 14 compared to the hypobaric normoxia group. Notably, the morphology and histology analyses showed that the size of tibial growth plates in AACs was enlarged and that the blood vessel density was also higher after exposure to the hypoxic environment for 14 days, while no such change was observed in TBCs. Altogether, our results revealed that the hypoxic environment has a potentially new role in increasing the blood vessel density of proximal tibial growth plates to strengthen and enhance the size of the growth plates, which may provide new insights for the therapeutic manipulation of hypoxia in poultry TD.

  7. Research on the sewage treatment in high altitude region based on Lhasa Sewage Treatment Plant

    Science.gov (United States)

    Xu, Jin; Li, Shuwen

    2017-12-01

    Sewage treatment is of great significance to enhance environmental quality, consolidate pollution prevention and ecological protection, and ensure sustainable economic and social development in high altitude region. However, there are numerous difficulties in sewage treatment due to the alpine climate, the relatively low economic development level, and the backward operation and management styles, etc. In this study, the characteristics of influent quality in the sewage treatment plant in Lhasa are investigated by analysing the influent BOD5/COD and BOD5/TN, comparing key indexes recorded from 2014 to 2016 with the hinterland. Results show that the concentration of influent COD, BOD5, NH3-N and SS in the Lhasa sewage treatment plant, in which the sewage belongs to low-concentration urban sewage, is smaller than that in the domestic sewage treatment plants in the mainland. The concentration ratio of BOD5/COD and BOD5/TN is below 0.4 and 4, which indicates that the biodegradation is poor and the carbon sources are in bad demand. The consequences obtained play a vital role in the design, operation and management of sewage treatment plants in high altitude region.

  8. Genotyping the High Altitude Mestizo Ecuadorian Population Affected with Prostate Cancer

    Directory of Open Access Journals (Sweden)

    Andrés López-Cortés

    2017-01-01

    Full Text Available Prostate cancer (PC is the second most commonly diagnosed type of cancer in males with 1,114,072 new cases in 2015. The MTHFR enzyme acts in the folate metabolism, which is essential in methylation and synthesis of nucleic acids. MTHFR C677T alters homocysteine levels and folate assimilation associated with DNA damage. Androgens play essential roles in prostate growth. The SRD5A2 enzyme metabolizes testosterone and the V89L polymorphism reduces in vivo SRD5A2 activity. The androgen receptor gene codes for a three-domain protein that contains two polymorphic trinucleotide repeats (CAG, GGC. Therefore, it is essential to know how PC risk is associated with clinical features and polymorphisms in high altitude Ecuadorian mestizo populations. We analyzed 480 healthy and 326 affected men from our three retrospective case-control studies. We found significant association between MTHFR C/T (odds ratio [OR] = 2.2; P=0.009, MTHFR C/T+T/T (OR = 2.22; P=0.009, and PC. The SRD5A2 A49T substitution was associated with higher pTNM stage (OR = 2.88; P=0.039 and elevated Gleason grade (OR = 3.15; P=0.004. Additionally, patients with ≤21 CAG repeats have an increased risk of developing PC (OR = 2.99; P<0.001. In conclusion, genotype polymorphism studies are important to characterize genetic variations in high altitude mestizo populations.

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

    Directory of Open Access Journals (Sweden)

    Cyril C. Grueter

    2012-01-01

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

  10. HIWRAP Radar Development for High-Altitude Operation on the NASA Global Hawk and ER-2

    Science.gov (United States)

    Li, Lihua; Heymsfield, Gerlad; Careswell, James; Schaubert, Dan; Creticos, Justin

    2011-01-01

    The NASA High-Altitude Imaging Wind and Rain Airborne Profiler (HIWRAP) is a solid-state transmitter-based, dual-frequency (Ka- and Ku-band), dual-beam (30 degree and 40 degree incidence angle), conical scan Doppler radar system, designed for operation on the NASA high-altitude (20 km) aircrafts, such as the Global Hawk Unmanned Aerial System (UAS). Supported by the NASA Instrument Incubator Program (IIP), HIWRAP was developed to provide high spatial and temporal resolution 3D wind and reflectivity data for the research of tropical cyclone and severe storms. With the simultaneous measurements at both Ku- and Ka-band two different incidence angles, HIWRAP is capable of imaging Doppler winds and volume backscattering from clouds and precipitation associated with tropical storms. In addition, HIWRAP is able to obtain ocean surface backscatter measurements for surface wind retrieval using an approach similar to QuikScat. There are three key technology advances for HIWRAP. Firstly, a compact dual-frequency, dual-beam conical scan antenna system was designed to fit the tight size and weight constraints of the aircraft platform. Secondly, The use of solid state transmitters along with a novel transmit waveform and pulse compression scheme has resulted in a system with improved performance to size, weight, and power ratios compared to typical tube based Doppler radars currently in use for clouds and precipitation measurements. Tube based radars require high voltage power supply and pressurization of the transmitter and radar front end that complicates system design and implementation. Solid state technology also significantly improves system reliability. Finally, HIWRAP technology advances also include the development of a high-speed digital receiver and processor to handle the complex receiving pulse sequences and high data rates resulting from multi receiver channels and conical scanning. This paper describes HIWRAP technology development for dual-frequency operation at

  11. Yoga Practice Improves Physiological and Biochemical Status at High Altitudes: A Prospective Case-control Study.

    Science.gov (United States)

    Himashree, Gidugu; Mohan, Latika; Singh, Yogesh

    2016-09-01

    Context • High altitude (HA) is a psychophysiological stressor for natives of lower altitudes. Reducing the morbidity and optimizing the performance of individuals deployed in an HA region has been attempted and reported with varied results. Objective • The present study intended to explore the effects of comprehensive yogic practices on the health and performance of Indian soldiers deployed at HAs. Design • The research team designed a prospective, randomized, case-control study. The study was done at Karu, Leh, India, at an altitude of 3445 m. Participants • Fully acclimatized soldiers in the Indian army were randomly selected from those posted to HA regions (ie, altitudes >3000 m). Intervention • The soldiers were divided into 2 groups of equal size. The first group, the control group, carried out the routine activities for physical training in the Indian army. The second group, the intervention group practiced a comprehensive yoga package, including physical asanas, pranayama, and meditation, and did not perform the physical training that the first group did. Both groups were monitored during their activities. Outcome Measures • A wide and comprehensive range of anthropometrical, physiological, biochemical, and psychological parameters were measured: (1) height and weight; (2) body fat percentage (BFP); (3) heart rate (HR); (4) respiratory rate (RR); (5) systolic and diastolic blood pressure (DPB); (6) peripheral saturation of oxygen; (7) end tidal CO2 (EtCO2); (8) chest expansion; (9) pulmonary function; (10) physical work capacity (VO2Max); (11) hematological variables; (12) lipid profile; (13) serum urea; (14) creatinine; (15) liver enzymes; (16) blood glucose; and (17) anxiety scores. Measurements were made at baseline and postintervention. Results • Two-hundred soldiers took part in the study. The yoga group showed a significant improvement in health indices and performance as compared with the control group. They had lower weights, BFPs, RRs

  12. Bioenergetics of the heart at high altitude: environmental hypoxia imposes profound transformations on the myocardial process of ATP synthesis.

    Science.gov (United States)

    Reynafarje, Baltazar D; Marticorena, Emilio

    2002-12-01

    The low concentration of O2 in the thin air at high altitude is undoubtedly the reason for the remarkable modifications in the structure and function of the heart, lung, and blood of humans permanently living under these conditions. The effect of natural hypoxia on the energy metabolism of the cell is however not well understood. Here we study the proces of ATP synthesis in the heart of guinea pigs native to high altitude (4500 m) as compared with those native to sea level. The following are the novel findings of this study. (1) The rates and extents of ATP synthesis in the presence of low concentrations of ADP (<30 microM) are significantly higher at high altitude than at sea level. (2) The Hill coefficient, i.e. the degree of cooperativity between the three catalytic sites of the ATP synthase, is lower at high altitude (n = 1.36) than at sea level (n = 1.94). (3) Both, the affinity for ADP and the fractional occupancy of the catalytic sites by ATP, are higher at high altitude than at sea level but the P50, i.e. the concentration of ADP at which 50% of the catalytic sites are filled with ADP and/or ATP, is the same (approximately 74.7 microM). (4) In the physiological range of ADP concentrations, the phosphorylation potential deltaGp is significantly higher at high altitude than at sea level. It is concluded that the molecular mechanism of energy transduction is profoundly modified at high altitude in order to readily and efficiently generate ATP in the presence of low concentrations of O2 and ADP.

  13. LOLAS-2: Redesign of an Optical Turbulence Profiler with High Altitude-resolution

    Science.gov (United States)

    Avila, R.; Zúñiga, C. A.; Tapia-Rodríguez, J. J.; Sánchez, L. J.; Cruz-González, I.; Avilés, J. L.; Valdés-Hernández, O.; Carrasco, E.

    2016-10-01

    We present the development, tests, and first results of the second-generation LOLAS-2. This instrument constitutes a strongly improved version of the prototype LOLAS, which is aimed at the measurement of optical turbulence profiles close to the ground, with high altitude-resolution. The method is based on the generalized Scidar principle that consists of taking double-star scintillation images on a defocused pupil plane and calculating in real time the autocovariance of the scintillation. The main components are an open-truss 40-cm Ritchey-Chrétien telescope, a German-type equatorial mount, an electron-multiplying CCD camera, and a dedicated acquisition and real-time data-processing software. The new optical design of LOLAS-2 is significantly simplified compared to the prototype. The experiments carried out to test the permanence of the image within the useful zone of the detector and the stability of the telescope focus show that LOLAS-2 can function without the use of the autoguiding and autofocus algorithms that were developed for the prototype version. Optical turbulence profiles obtained with the new LOLAS have the best altitude-resolution ever achieved with Scidar-like techniques (6.3 m). The simplification of the optical layout and the improved mechanical properties of the telescope and mount make of LOLAS-2 a more robust instrument.

  14. Mount St. Helens Quick Response Damage Assessment Using High-Altitude Infrared Photography

    Science.gov (United States)

    Hinkle, Richard E.; Prill, James C.; Pruitt, John R.

    1981-11-01

    After the destructive volcanic eruption of Mount St. Helens on May 18, 1980, there was a need for a quick response damage assessment. Timeliness of the information was emphasized because of the need to immediately devise land man-agement plans for timber sale operations, rehabilitation efforts, fire protection activities, and areas to be preserved. High-altitude color-infrared photography was collected during May and June by the National Aeronautics and Space Administra-tion (NASA) Ames Research Center (ARC). Interpretation of the photography plus a helicopter trip into the area provided the basis for the construction of 58 map-registered overlays within a 3-week period. These overlays depicted in detail the damage to timber resources, the transportation network, and the watershed. Using the 14 timber loss overlays, U.S. Department of Agriculture (USDA) Forest Service personnel were able to digitize cells depicting ownership, degree of damage, and the preeruption cover classes. These digitized data provided such informa-tion as the total area affected within and outside the national forest, total timber acreage destroyed and damaged, the sizes of timber destroyed, and the acreage of barren land both before and after the eruption. The hydrology and transportation overlays provided information for an alert system to locate areas needing in-depth studies. These problem areas were then studied in detail on low-altitude color photography so that potential erosion sites could receive preventive treatments and essential access roads needed for fire control and timber salvage could be repaired.

  15. Pruning management of Chardonnay grapevines at high altitude in Brazilian southeast

    Directory of Open Access Journals (Sweden)

    Tania dos Reis Mendonça

    2016-03-01

    Full Text Available ABSTRACT The agronomical responses of Chardonnay, a variety indicated for sparkling wine production, is influenced by the vineyard management and the edaphoclimatic conditions of the region. The objective of this study was to evaluate the effects of two pruning types (Royat and double Guyot on vegetative and reproductive development of Chardonnay vine growing at high altitude in the Brazilian southeastern region. The experiment was carried out in a commercial vineyard located at 1,280 m of altitude in Divinolândia, São Paulo State, Brazil. The Chardonnay vines (clone 96, grafted onto 1103 Paulsen rootstock and trained in a vertical shoot positioning trellis system, were assessed. Vegetative vigor, bud fruitfulness, production and physicochemical composition of grapes were evaluated during 2014 and 2015 growing seasons. The Royat pruning induced higher vegetative vigor and increased the bud fruitfulness, the cluster number and the productivity of Chardonnay vine when compared to Guyot pruning. Even though the increase on yield was observed, there was no effect of pruning type on grape final quality. Therefore, the choice of pruning method in function of variety genetic characteristics and their interaction with environment can optimize the vineyard profitability. In the Brazilian southeast, the Royat system is the most suitable one to grow Chardonnay for sparkling wines production.

  16. Hydrogen Fuel System Design Trades for High-Altitude Long-Endurance Remotely- Operated Aircraft

    Science.gov (United States)

    Millis, Marc G.; Tornabene, Robert T.; Jurns, John M.; Guynn, Mark D.; Tomsik, Thomas M.; VanOverbeke, Thomas J.

    2009-01-01

    Preliminary design trades are presented for liquid hydrogen fuel systems for remotely-operated, high-altitude aircraft that accommodate three different propulsion options: internal combustion engines, and electric motors powered by either polymer electrolyte membrane fuel cells or solid oxide fuel cells. Mission goal is sustained cruise at 60,000 ft altitude, with duration-aloft a key parameter. The subject aircraft specifies an engine power of 143 to 148 hp, gross liftoff weight of 9270 to 9450 lb, payload of 440 lb, and a hydrogen fuel capacity of 2650 to 2755 lb stored in two spherical tanks (8.5 ft inside diameter), each with a dry mass goal of 316 lb. Hydrogen schematics for all three propulsion options are provided. Each employs vacuum-jacketed tanks with multilayer insulation, augmented with a helium pressurant system, and using electric motor driven hydrogen pumps. The most significant schematic differences involve the heat exchangers and hydrogen reclamation equipment. Heat balances indicate that mission durations of 10 to 16 days appear achievable. The dry mass for the hydrogen system is estimated to be 1900 lb, including 645 lb for each tank. This tank mass is roughly twice that of the advanced tanks assumed in the initial conceptual vehicle. Control strategies are not addressed, nor are procedures for filling and draining the tanks.

  17. Cryptic differentiation in alpine-endemic, high-altitude butterflies reveals down-slope glacial refugia.

    Science.gov (United States)

    Haubrich, Karola; Schmitt, Thomas

    2007-09-01

    The influence of cyclic climate fluctuations and their impact on high-altitude species is still insufficiently understood. We therefore analysed in this study the genetic structure of cold-adapted animals and their coherence with geographical distributions throughout the Late Quaternary. We analysed 588 individuals from 23 populations of the alpine-endemic lesser mountain ringlet, Erebia melampus, by allozyme electrophoresis to detect its intraspecific differentiation. As an outgroup, we added one population of Erebia sudetica inalpina from Grindelwald (Swiss Alps). Seventeen of 18 loci were polymorphic. The mean F(ST) over all samples was 37%. We detected strong differentiation into three lineages with the genetic distances between the two E. melampus groups being larger than between each of the two E. melampus groups and E. sudetica. The mean genetic distance among these three groups was 0.17. These results give evidence for the existence of a species complex within the E. melampus/sudetica group and indicate a discontinuous distribution within this group during at least the last ice age. One of them, E. sudetica inalpina, is found in the northern Alps and most probably had its Würm glacial refugium north of the glaciated Alps. The western E. melampus group might have had a refugium at the southwestern Alps margin, the eastern group in the lower altitudes of the southeastern and/or eastern Alps. In the latter, a further subdivision within this relict area is possible.

  18. Intracranial hemorrhage during aeromedical transport and correlation with high altitude adaptations in the brain

    Directory of Open Access Journals (Sweden)

    Kouliev T

    2012-12-01

    Full Text Available Timur Kouliev,1 Airron Richardson,2 Cai Glushak3,41Beijing United Family Hospital, Beijing, People's Republic of China; 2Department of Emergency Medicine, The Methodist Hospitals, Gary, IN, 3AXA Assistance USA, Chicago, IL; 4Section of Emergency Medicine, University of Chicago, Chicago, IL, USAAbstract: Aeromedical transport is challenging not only because of limitations of equipment, unfamiliar surroundings, and challenging environmental conditions, but also due to difficulty in developing methodologies for research and data collection. To our knowledge, neurological changes at the oxygen tensions of a pressurized cabin have not been systematically studied. Here we report a case of intracranial hemorrhage during aeromedical transport and review the body's cardiovascular and respiratory adaptation to decreased ambient oxygen tension. Previous experience with high altitude cerebral edema serves as guidance for mitigating the effects of vasogenic edema in patients at risk of neurological events who travel by air. Review of this case and relevant altitude-related physiological changes may be grounds for more conservative recommendations on aeromedical transport after an acute neurological event.Keywords: pediatric, disaster, triage, equity, pregnancy, survival

  19. 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

  20. Weather Avoidance Guidelines for NASA Global Hawk High-Altitude Unmanned Aircraft Systems (UAS)

    Science.gov (United States)

    Cecil, Daniel J.; Zipser, Edward J.; Velden, Chris S.; Monette, Sarah A.; Heymsfield, Gerald M.; Braun, Scott A.; Newman, Paul A.; Black, Peter G.; Black, Michael L.; Dunion, Jason P.

    2014-01-01

    The current Global Hawk flight rules would probably not have been effective in the single event of greatest concern (the Emily encounter). The cloud top had not reached 50,000 ft until minutes before the encounter. The TOT and lightning data would not have been available until near the overflight time since this was a rapidly growing cell. This case would have required a last-minute diversion when lightning became frequent. Avoiding such a cell probably requires continual monitoring of the forward camera and storm scope, whether or not cloud tops have been exceeding specific limits. However, the current overflight rules as strictly interpreted would have prohibited significant fractions of the successful Global Hawk overpasses of Karl and Matthew that proved not to be hazardous. Many other high altitude aircraft (ER-2 and Global Hawk) flights in NASA tropical cyclone field programs have successfully overflown deep convective clouds without incident.The convective cell that caused serious concern about the safety of the ER-2 in Emily was especially strong for a tropical cyclone environment, probably as strong or stronger than any that was overflown by the ER-2 in 20 previous flights over tropical cyclones. Specifically, what made that cell a safety concern was the magnitude of the vertical velocity of the updraft, at least 20 m/s (4000 ft/minute) at the time the ER-2 overflew it. Such a strong updraft can generate strong gravity waves at and above the tropopause, posing a potential danger to aircraft far above the maximum altitude of the updraft itself or its associated cloud top. Indeed, the ER-2 was probably at least 9000 ft above that cloud top. Cloud-top height, by itself, is not an especially good indicator of the intensity of convection and the likelihood of turbulence. Nor is overflying high cloud tops (i.e. > 50,000 ft) of particular concern unless there is other evidence of very strong convective updrafts beneath those tops in the path of the aircraft

  1. Design of a high altitude long endurance flying-wing solar-powered unmanned air vehicle

    Science.gov (United States)

    Alsahlani, A. A.; Johnston, L. J.; Atcliffe, P. A.

    2017-06-01

    The low-Reynolds number environment of high-altitude §ight places severe demands on the aerodynamic design and stability and control of a high altitude, long endurance (HALE) unmanned air vehicle (UAV). The aerodynamic efficiency of a §ying-wing configuration makes it an attractive design option for such an application and is investigated in the present work. The proposed configuration has a high-aspect ratio, swept-wing planform, the wing sweep being necessary to provide an adequate moment arm for outboard longitudinal and lateral control surfaces. A design optimization framework is developed under a MATLAB environment, combining aerodynamic, structural, and stability analysis. Low-order analysis tools are employed to facilitate efficient computations, which is important when there are multiple optimization loops for the various engineering analyses. In particular, a vortex-lattice method is used to compute the wing planform aerodynamics, coupled to a twodimensional (2D) panel method to derive aerofoil sectional characteristics. Integral boundary-layer methods are coupled to the panel method in order to predict §ow separation boundaries during the design iterations. A quasi-analytical method is adapted for application to flyingwing con¦gurations to predict the wing weight and a linear finite-beam element approach is used for structural analysis of the wing-box. Stability is a particular concern in the low-density environment of high-altitude flight for flying-wing aircraft and so provision of adequate directional stability and control power forms part of the optimization process. At present, a modified Genetic Algorithm is used in all of the optimization loops. Each of the low-order engineering analysis tools is validated using higher-order methods to provide con¦dence in the use of these computationally-efficient tools in the present design-optimization framework. This paper includes the results of employing the present optimization tools in the design of a

  2. Aerodynamic design and optimization of high altitude environment simulation system based on CFD

    Science.gov (United States)

    Ma, Pingchang; Yan, Lutao; Li, Hong

    2017-05-01

    High altitude environment simulation system (HAES) is built to provide a true flight environment for subsonic vehicles, with low density, high speed, and short time characteristics. Normally, wind tunnel experiments are based on similar principal, such as parameters of Re or Ma, in order to shorten test product size. However, the test products in HAES are trim size, so more attention is put on the true flight environment simulation. It includes real flight environment pressure, destiny and real flight velocity, and its type velocity is Ma=0.8. In this paper, the aerodynamic design of HAES is introduced and its rationality is explained according to CFD calculation based on Fluent. Besides, the initial pressure of vacuum tank in HAES is optimized, which is not only to meet the economic requirements, but also to decrease the effect of additional stress on the test product in the process of the establishment of the target flow field.

  3. High Altitude Platforms for Disaster Recovery: Capabilities, Strategies, and Techniques for Emergency Telecommunications

    Directory of Open Access Journals (Sweden)

    Deaton JuanD

    2008-01-01

    Full Text Available Abstract Natural disasters and terrorist acts have significant potential to disrupt emergency communication systems. These emergency communication networks include first-responder, cellular, landline, and emergency answering services such as 911, 112, or 999. Without these essential emergency communications capabilities, search, rescue, and recovery operations during a catastrophic event will be severely debilitated. High altitude platforms could be fitted with telecommunications equipment and used to support these critical communications missions once the catastrophic event occurs. With the ability to be continuously on station, HAPs provide excellent options for providing emergency coverage over high-risk areas before catastrophic incidents occur. HAPs could also provide enhanced 911 capabilities using either GPS or reference stations. This paper proposes potential emergency communications architecture and presents a method for estimating emergency communications systems traffic patterns for a catastrophic event.

  4. High Altitude Platforms for Disaster Recovery: Capabilities, Strategies, and Techniques for Emergency Telecommunications

    Directory of Open Access Journals (Sweden)

    Juan D. Deaton

    2008-09-01

    Full Text Available Natural disasters and terrorist acts have significant potential to disrupt emergency communication systems. These emergency communication networks include first-responder, cellular, landline, and emergency answering services such as 911, 112, or 999. Without these essential emergency communications capabilities, search, rescue, and recovery operations during a catastrophic event will be severely debilitated. High altitude platforms could be fitted with telecommunications equipment and used to support these critical communications missions once the catastrophic event occurs. With the ability to be continuously on station, HAPs provide excellent options for providing emergency coverage over high-risk areas before catastrophic incidents occur. HAPs could also provide enhanced 911 capabilities using either GPS or reference stations. This paper proposes potential emergency communications architecture and presents a method for estimating emergency communications systems traffic patterns for a catastrophic event.

  5. Prokaryotic diversity pattern in high-altitude ecosystems of the Chilean Altiplano

    Science.gov (United States)

    Demergasso, Cecilia; Dorador, Cristina; Meneses, Daniela; Blamey, Jenny; Cabrol, Nathalie; Escudero, Lorena; Chong, Guillermo

    2010-06-01

    The Chilean Altiplano is the westernmost part of a large volcanic-sedimentary plateau in the central Andes. High solar irradiance and rapid increase of temperature have contributed to make it a hot spot of global climatic change. In this study, we describe microbial diversity in the summit lake of the Simba volcano (5,870 m) and the evaporitic basins of Salar de Aguas Calientes (4,200 m) and Laguna Lejía (4,325 m) using both culture and culture-independent methods. The results obtained were analyzed together with available information from related environments to describe the traits of the microbial community driven by main environmental factors. Isolated cultures exhibit high resistance to all three types of UV radiation, further supporting the adaptation of microorganisms to the high altitude environment. The microbial community structures at Salar de Aguas Calientes and Laguna Lejía are similar to those from other saline systems and cold environments where Bacteroidetes is the major bacterial group. The abundance of sequences related to alphaproteobacteria and methanogenic populations likely reflects the importance of aerobic anoxigenic phothosynthesis and the cycling of one-carbon compounds in the high altitude lake ecosystems. Geochemistry and microbial communities at Simba as well as those reported in the Licancabur summit lake provide evidence for sulfur-rich environments but under different conditions. Those differences between neighboring mountain lake ecosystems highlight the effect of volcanic activity on microbial communities. The hypothetical ecosystem model described in this work provides a clue to follow the microbial community responses to geophysical environment coupled with rapid climate change.

  6. Analysis of the neutron component and determination of the LET spectrum at high altitudes

    Energy Technology Data Exchange (ETDEWEB)

    Vana, N.; Minarik, M.; Schoener, W. [Atoministitute of the Austrian Universities, Stadionallee 2, A-1020 Vienna (Austria); Berger, T.; Hajek, M.; Noll, M. [Institute for Space Dosimetry, Lustkandlgasse 52/3, A-1090 Vienna (Austria)

    2000-05-01

    The European Council directive 96/29/Euratom of 13 May 1996 emphasizes the introduction of two categories for occupational exposure. Category A includes the employees for whom the annual effective dose is likely to exceed 6 mSv. Suggesting an average flight time between 600 and 1000 hours per year for aircrew, the typical annual dose lies between 4 and 8 mSv with a maximum value of 15 mSv for Concorde flights. This requires the surveillance of aircrew members and thus the development of proper measurement devices. Because of the similar radiation environment, high altitude mountains seem to be an ideal choice to test and to improve recently developed measurement systems. Bonner Sphere Spectrometers (BSS) with a {sup 6}LiI(Eu) scintillation counter and thermoluminescent dosemeters (TLDs), respectively, were used to determine the neutron energy spectrum as well as the absorbed dose and the average linear energy transfer (LET) in a complex mixed radiation field on top of Mt. Sonnblick (3105 m). The neutron component makes up 35 to 60% of the biologically relevant dose at high altitudes, depending on the geomagnetic latitude. The average LET of the mixed radiation field was determined using the high temperature ratio (HTR)-method. Paired TLD-600 and TLD-700 dosemeters as well as an extended range Sievert counter were employed for determination of the neutron dose equivalent. Furthermore, a LET spectrum was recorded on Mt. Kitzsteinhorn (3029 m) using the laboratory-manufactured tissue equivalent proportional counter (TEPC)-system PART. All detectors were calibrated with standard radiation sources and in the CERN EC neutron reference field. The measurements performed with the passive BSS as well as the Sievert counters show that there exists a neutron component with energies up to 100 MeV (and probably more) at such altitudes. The total dose equivalent rate measured on top of Mt. Sonnblick was 200 nSv.h{sup -1} compared to an absorbed dose rate of 120 nGy.h{sup -1}. The

  7. Comparison of live high: train low altitude and intermittent hypoxic exposure.

    Science.gov (United States)

    Humberstone-Gough, Clare E; Saunders, Philo U; Bonetti, Darrell L; Stephens, Shaun; Bullock, Nicola; Anson, Judith M; Gore, Christopher J

    2013-01-01

    Live High:Train Low (LHTL) altitude training is a popular ergogenic aid amongst athletes. An alternative hypoxia protocol, acute (60-90 min daily) Intermittent Hypoxic Exposure (IHE), has shown potential for improving athletic performance. The aim of this study was to compare directly the effects of LHTL and IHE on the running and blood characteristics of elite triathletes. Changes in total haemoglobin mass (Hbmass), maximal oxygen consumption (VO2max), velocity at VO2max (vVO2max), time to exhaustion (TTE), running economy, maximal blood lactate concentration ([La]) and 3 mM [La] running speed were compared following 17 days of LHTL (240 h of hypoxia), IHE (10.2 h of hypoxia) or Placebo treatment in 24 Australian National Team triathletes (7 female, 17 male). There was a clear 3.2 ± 4.8% (mean ± 90% confidence limits) increase in Hbmass following LHTL compared with Placebo, whereas the corresponding change of -1.4 ± 4.5% in IHE was unclear. Following LHTL, running economy was 2.8 ± 4.4% improved compared to IHE and 3mM [La] running speed was 4.4 ± 4.5% improved compared to Placebo. After IHE, there were no beneficial changes in running economy or 3mM [La] running speed compared to Placebo. There were no clear changes in VO2max, vVO2max and TTE following either method of hypoxia. The clear difference in Hbmass response between LHTL and IHE indicated that the dose of hypoxia in IHE was insufficient to induce accelerated erythropoiesis. Improved running economy and 3mM [La] running speed following LHTL suggested that this method of hypoxic exposure may enhance performance at submaximal running speeds. Overall, there was no evidence to support the use of IHE in elite triathletes. Key PointsDespite a clear 3.2% increase in haemoglobin mass following 17 days of Live High: Train Low altitude training, no change in maximal aerobic capacity was observed.There were positive changes in running economy and the lactate-speed relationship at submaximal running speeds

  8. Cane pruning on Chardonnay grapevine in the high-altitude regions of Southern Brazil

    Directory of Open Access Journals (Sweden)

    Filho José Luiz Marcon

    2016-01-01

    Full Text Available High-altitude regions of southern Brazil, located above 900 m above sea level, the cordon training with spur pruning is widely used because of easier application. In these regions, Chardonnay wine grape shows potential to produce quality wines, however, in commercial vineyards, the training system used has not provided productivities that makes economically viable the cultivation of this variety. Given this, the present study aimed to evaluate the effect of different cane-pruning systems on the vegetative, productive and enological potential of Chardonnay grapevines grown in the high-altitude region of Southern Brazil. The experiment was conducted in a commercial Chardonnay vineyard, located in São Joaquim – Santa Catarina State (28o17 ′39”S and 49∘ 55′56” W, to 1230 m a.s.l during 2015 and 2016 vintages. Chardonnay vines (grafted on 1103 Paulsen were planted in 2010, with a 3.0 m (row × 1.0 m (vine spacing. The treatments consisted of different cane-pruning systems: Cordon spur-pruning (control; Sylvoz; Cazenave; Capovolto; single Guyot and double Guyot. Pruning was performed in August of each year when the buds were in the green tip developmental stage. Data was analyzed by Scott Knott test (p < 0.05 following a randomized block design with four replicates, each consisting of 12 vines per plot. We observed higher yield in the Cazenave and double Guyot training system with three and two more tons of grapes than spur-pruning respectively. The bud fertility was higher in plants trained in double Guyot. Vines spur-pruned showed higher relation of leaf area: production, with values above 100 cm2 g−1 grape at 2016 vintage. Commercial maturity of grapes (soluble solids, acidity and polyphenols did not differ among training systems studied. The results suggest that cane-pruning systems could be an alternative to increase production efficiency of Chardonnay in high-altitude region of southern Brazil.

  9. Hemoglobin correction factors for estimating the prevalence of iron deficiency anemia in pregnant women residing at high altitudes in Bolivia

    Directory of Open Access Journals (Sweden)

    Jennifer Hadary Cohen

    1999-12-01

    Full Text Available This study had two primary objectives: 1 to derive a method to determine hemoglobin cutoffs that could be used to better estimate the prevalence of iron deficiency anemia in pregnancy at high altitudes and 2 to estimate the prevalence of anemia in a sample of pregnant women residing in two cities in Bolivia, La Paz (3 600 meters and El Alto (4 000 meters. We derived a hemoglobin-altitude curve from previously published data on the mean hemoglobin concentrations of nonanemic women of childbearing age at various altitudes. In addition, we abstracted data on hemoglobin concentration during pregnancy from medical records of women from La Paz and El Alto who had given birth at a maternity hospital in La Paz between January and June of 1996. Using our approach and two other previously published, currently used methods, we calculated and compared prevalences of iron deficiency anemia in this population using hemoglobin cutoffs determined from a hemoglobin-altitude curve corrected for pregnancy. The hemoglobin-altitude curve derived in this study provided a better fit to data for women of childbearing age than the two other models. Those models used cutoffs based on non-iron-replete populations of children or men, both of which were residing below 4 000 m, and then extrapolated to women and higher altitudes. The estimated prevalences of iron deficiency anemia in pregnancy using the hemoglobin cutoffs determined in this study were higher than those estimated by the two other approaches.

  10. High efficient kite for harvesting high altitude wind power: Investigation of new concepts and materials for the structure

    OpenAIRE

    Girbau Lloch, Gerard

    2012-01-01

    The Center for Synergetic Structures at EMPA is currently developing high efficient ultra-light plane-like structures, known as Twing, for generating wind energy at high altitudes. This work is part of a larger collaborative project called Swiss Kite Power in which other universities are involved. The elec-tricity is produced by the tension of a rope which connects the ground generator with the flying Twing. The structure needs to be lightweight enough to be airborne and it is required to ...

  11. Ecological status of high altitude medicinal plants and their sustainability: Lingshi, Bhutan.

    Science.gov (United States)

    Lakey; Dorji, Kinley

    2016-10-11

    Human beings use plants for a multitude of purposes of which a prominent one across the globe is for their medicinal values. Medicinal plants serve as one of the major sources of income for high altitude inhabitants in the Himalaya, particularly in countries like Nepal, and Bhutan. People here harvest huge volumes of medicinal plants indiscriminately, risking their sustainability. This paper attempts to identify some of the priority medicinal plant species harvested in the wild and assess their ecological status for their judicious utilization, and to help provide policy guidance for possible domestication and support strategic conservation frameworks. Out of the 16 priority species identified by the expert group, collectors' perception on ecological status of the priority species differed from survey findings. Chrysosplenium nudicaule (clumps) ranked as most threatened species followed by Corydalis dubia, and Meconopsis simplicifolia. Onosma hookeri, Corydalis crispa and Delphinium glaciale were some of the species ranked as threatened species followed by Halenia elliptica (not in priority list). Percent relative abundance showed irregular pattern of species distribution. High species evenness was recorded among Nardostachys grandiflora, Chrysosplenium nudicaule, Saussurea gossypiphora and Aconitum orochryseum with average species density of 8 plant m-2. Rhodiola crenulata, and Dactylorhiza hatagirea followed by Meconopsis horridula and Meconopsis simplicifolia were ranked as most threatened species with average species density of 0.4, 0.4, 5.6 and 6.0 plant m-2, respectively. The most abundant (common) species was Onosma hookeri (plant m-2). Species composition and density also differed with vegetation, altitude, slope and its aspects. Priority species identified by expert group were found vulnerable and patchy in distribution. Survey results and collectors' perceptions tally to an extent. Some of the species (Dactylorhiza hatagirea, Rhodiola crenulata

  12. Application of ameliorative and adaptive approaches to revegetation of historic high altitude mining waste

    Energy Technology Data Exchange (ETDEWEB)

    Bellitto, M.W.; Williams, H.T.; Ward, J.N.

    1999-07-01

    High altitude, historic, gold and silver tailings deposits, which included a more recent cyanide heap leach operation, were decommissioned, detoxified, re-contoured and revegetated. Detoxification of the heap included rinsing with hydrogen peroxide, lime and ferric chloride, followed by evaporation and land application of remaining solution. Grading included the removal of solution ponds, construction of a geosynthetic/clay lined pond, heap removal and site drainage development. Ameliorative and adaptive revegetation methodologies were utilized. Revegetation was complicated by limited access, lack of topsoil, low pH and evaluated metals concentrations in the tailings, and a harsh climate. Water quality sampling results for the first year following revegetation, indicate reclamation activities have contributed to a decrease in metals and sediment loading to surface waters downgradient of the site. Procedures, methodologies and results, following the first year of vegetation growth, are provided.

  13. Doppler Lidar Observations over a High Altitude Mountainous Site Manora Peak in the Central Himalayan Region

    Energy Technology Data Exchange (ETDEWEB)

    Phanikumar, D. V.; Shukla, K. K.; Naja, M.; Singh, N.; Sahai, S.; Sagar, R.; Satheesh, S. K.; Moorthy, K. K.; Kotamarthi, V. R.; Newsom, Rob K.

    2016-07-10

    The RAWEX-GVAX field campaign has been carried out from June 2011 to March 2012 over a high altitude site Manora Peak, Nainital (29.4 degrees N; 79.2 degrees E; 1958 m amsl) in the central Himalayas to assess the impacts of absorbing aerosols on atmospheric thermodynamics and clouds. This paper presents the preliminary results of the observations and data analysis of the Doppler Lidar, installed at Nainital. Strong updrafts with vertical winds in the range of similar to 2-4 ms(-1) occurred during the daytime and throughout the season indicating thermally driven convection. On the other hand during nighttime, weak downdrafts persisted during stable conditions. Plan Position Indicator scan of Doppler Lidar showed north-northwesterly winds in the boundary layer. The mixing layer height, derived from the vertical velocity variance, showed diurnal variations, in the range similar to 0.7-1 km above ground level during daytime and very shallow during nighttime.

  14. Provision of 3G Mobile Services in Sparsely Populated Areas Using High Altitude Platforms

    Directory of Open Access Journals (Sweden)

    J. Holis

    2008-04-01

    Full Text Available This paper deals with the application of High Altitude Platforms for the provision of third generation mobile services in sparsely-populated areas or in developing countries. It focuses on the behavior of large cells provided via a multiple HAP deployment and shows the possibilities of using small cells located inside these large cells to serve hot-spot areas. The impact of the different types of HAP antenna masks and their adjustment on cell capacity and the quality of coverage is presented. The main parameter of the antenna radiation pattern under investigation is the power roll-off at the cell edge. Optimal values of this parameter are presented for different scenarios. Simulations of system level parameters were based on an iteration loops approach.

  15. The Channel Estimation and Modeling in High Altitude Platform Station Wireless Communication Dynamic Network

    Directory of Open Access Journals (Sweden)

    Xiaoyang Liu

    2017-01-01

    Full Text Available In order to analyze the channel estimation performance of near space high altitude platform station (HAPS in wireless communication system, the structure and formation of HAPS are studied in this paper. The traditional Least Squares (LS channel estimation method and Singular Value Decomposition-Linear Minimum Mean-Squared (SVD-LMMS channel estimation method are compared and investigated. A novel channel estimation method and model are proposed. The channel estimation performance of HAPS is studied deeply. The simulation and theoretical analysis results show that the performance of the proposed method is better than the traditional methods. The lower Bit Error Rate (BER and higher Signal Noise Ratio (SNR can be obtained by the proposed method compared with the LS and SVD-LMMS methods.

  16. Avionics and Power Management for Low-Cost High-Altitude Balloon Science Platforms

    Science.gov (United States)

    Chin, Jeffrey; Roberts, Anthony; McNatt, Jeremiah

    2016-01-01

    High-altitude balloons (HABs) have become popular as educational and scientific platforms for planetary research. This document outlines key components for missions where low cost and rapid development are desired. As an alternative to ground-based vacuum and thermal testing, these systems can be flight tested at comparable costs. Communication, solar, space, and atmospheric sensing experiments often require environments where ground level testing can be challenging or impossible in certain cases. When performing HAB research the ability to monitor the status of the platform and gather data is key for both scientific and recoverability aspects of the mission. A few turnkey platform solutions are outlined that leverage rapidly evolving open-source engineering ecosystems. Rather than building custom components from scratch, these recommendations attempt to maximize simplicity and cost of HAB platforms to make launches more accessible to everyone.

  17. Mixing effectiveness test of an exhaust gas mixer in a high bypass turbofan at altitude

    Science.gov (United States)

    Cullom, R. R.; Burkardt, L. A.; Bobula, G. A.

    1981-01-01

    Thermal mixing effectiveness characteristics of an eighteen lobe, scalloped and unscalloped, partial, forced mixer were measured in a high-bypass turbofan engine. Data were also obtained without the mixer installed, i.e. free mixing. Tests were conducted at four combinations of simulated flight conditions from 0.3 to 0.8 Mach number and from 6,096 meters (20,000 ft) to 13,715 m (45,000 ft) altitude. Mixing chamber lengths of L/D = 0.52 and 0.65 were tested. For this range of test conditions and mixer configurations the forced mixing effectiveness varied from 59 to 68 percent. Values of mixing effectiveness and total pressure loss were calculated from temperature and pressure data obtained at the mixer inlet and exhaust nozzle exit.

  18. Perinatal hypoxia increases susceptibility to high-altitude polycythemia and attendant pulmonary vascular dysfunction.

    Science.gov (United States)

    Julian, Colleen Glyde; Gonzales, Marcelino; Rodriguez, Armando; Bellido, Diva; Salmon, Carlos Salinas; Ladenburger, Anne; Reardon, Lindsay; Vargas, Enrique; Moore, Lorna G

    2015-08-15

    Perinatal exposures exert a profound influence on physiological function, including developmental processes vital for efficient pulmonary gas transfer throughout the lifespan. We extend the concept of developmental programming to chronic mountain sickness (CMS), a debilitating syndrome marked by polycythemia, ventilatory impairment, and pulmonary hypertension that affects ∼10% of male high-altitude residents. We hypothesized that adverse perinatal oxygenation caused abnormalities of ventilatory and/or pulmonary vascular function that increased susceptibility to CMS in adulthood. Subjects were 67 male high-altitude (3,600-4,100 m) residents aged 18-25 yr with excessive erythrocytosis (EE, Hb concentration ≥18.3 g/dl), a preclinical form of CMS, and 66 controls identified from a community-based survey (n = 981). EE subjects not only had higher Hb concentrations and erythrocyte counts, but also lower alveolar ventilation, impaired pulmonary diffusion capacity, higher systolic pulmonary artery pressure, lower pulmonary artery acceleration time, and more frequent right ventricular hypertrophy, than controls. Compared with controls, EE subjects were more often born to mothers experiencing hypertensive complications of pregnancy and hypoxia during the perinatal period, with each increasing the risk of developing EE (odds ratio = 5.25, P = 0.05 and odds ratio = 6.44, P = 0.04, respectively) after other factors known to influence EE status were taken into account. Adverse perinatal oxygenation is associated with increased susceptibility to EE accompanied by modest abnormalities of the pulmonary circulation that are independent of increased blood viscosity. The association between perinatal hypoxia and EE may be due to disrupted alveolarization and microvascular development, leading to impaired gas exchange and/or pulmonary hypertension. Copyright © 2015 the American Physiological Society.

  19. PHYTOCHEMICAL AND PROTEOMIC ANALYSIS OF A HIGH ALTITUDE MEDICINAL MUSHROOM CORDYCEPS SINENSIS

    Directory of Open Access Journals (Sweden)

    Rakhee

    2016-09-01

    Full Text Available Cordyceps sinensis (C. sinensis is well established as a traditional Chinese medicine (TCM that has been valued as a health food for centuries. It is an entomopathogenic fungus in Ascomycetes that naturally occurs at high altitude in Himalayan region and has received considerable attention due to the abundance of various biologically active compounds. Despite having reported health benefits and economic importance, qualitative phytochemical analysis, proximate composition and proteome study of Indian isolates of C. sinensis grown at high altitude remains untapped. In the present study, qualitative phytochemical analysis was carried on powdered whole body of C. sinensis (CSWb and its aqueous extract (CSAq prepared by accelerated solvent extraction technique which indicated the presence of several bioactive constituents such as alkaloids, amino acids and proteins, carbohydrates, flavonoids and phenols, gums, mucilages and saponins. We evaluated chemical composition of the Indian Himalayan medicinal mushroom C. sinensis in terms of its carbohydrate (55.68% content, crude fiber (6.40%, fat (1.80%, moisture (7.18%, protein (21.46% and total ash (7.48%. Furthermore, soluble protein identification of both CSWb and CSAq by SDS-PAGE followed by MALDI-TOF-TOF analysis revealed the presence of various types of most abundant proteins such as P-type II A ATPase, TE1b [Blumeriagraminis f. sp. hordei], Chitin synthase Chs [Penicilliummarneffei ATCC 18224], Serine/threonine-protein kinase CLA4, DEHA2C06820p [Debaryomyceshansenii CBS767], YALI0E29887p [Yarrowialipolytica] etc. In conclusion, the present study provides a comprehensive qualitative phytochemical analysis, proximate composition and proteome study on Indian isolate of C. sinensis which could endorse its use as a functional food.

  20. High-altitude exposure of three weeks duration increases lung diffusing capacity in humans.

    Science.gov (United States)

    Agostoni, Piergiuseppe; Swenson, Erik R; Bussotti, Maurizio; Revera, Miriam; Meriggi, Paolo; Faini, Andrea; Lombardi, Carolina; Bilo, Grzegorz; Giuliano, Andrea; Bonacina, Daniele; Modesti, Pietro A; Mancia, Giuseppe; Parati, Gianfranco

    2011-06-01

    high-altitude adaptation leads to progressive increase in arterial Pa(O2). In addition to increased ventilation, better arterial oxygenation may reflect improvements in lung gas exchange. Previous investigations reveal alterations at the alveolar-capillary barrier indicative of decreased resistance to gas exchange with prolonged hypoxia adaptation, but how quickly this occurs is unknown. Carbon monoxide lung diffusing capacity and its major determinants, hemoglobin, alveolar volume, pulmonary capillary blood volume, and alveolar-capillary membrane diffusion, have never been examined with early high-altitude adaptation. lung diffusion was measured in 33 healthy lowlanders at sea level (Milan, Italy) and at Mount Everest South Base Camp (5,400 m) after a 9-day trek and 2-wk residence at 5,400 m. Measurements were adjusted for hemoglobin and inspired oxygen. Subjects with mountain sickness were excluded. After 2 wk at 5,400 m, hemoglobin oxygen saturation increased from 77.2 ± 6.0 to 85.3 ± 3.6%. Compared with sea level, there were increases in hemoglobin, lung diffusing capacity, membrane diffusion, and alveolar volume from 14.2 ± 1.2 to 17.2 ± 1.8 g/dl (P volume was unchanged. Membrane diffusion normalized for alveolar volume was 10.9 ± 5.2 at sea level rising to 16.0 ± 9.2 ml·min(-1)·mmHg(-1)·l(-1) (P lung diffusing capacity improves with acclimatization due to increases of hemoglobin, alveolar volume, and membrane diffusion. Reduction in alveolar-capillary barrier resistance is possibly mediated by an increase of sympathetic tone and can develop in 3 wk.

  1. High-altitude and high-latitude O+ and H+ outflows: the effect of finite electromagnetic turbulence wavelength

    Directory of Open Access Journals (Sweden)

    A. A. Saleh

    2007-11-01

    , consistent with the observations of H+ and O+ ions in the auroral region at high altitudes.

  2. The protective effeet of hyperbaric oxygen against hepatic injury in septic rats under acute hypoxia of simulated high altitude

    Directory of Open Access Journals (Sweden)

    Ke LIU

    2011-02-01

    Full Text Available Objective To investigate the protective effect of hyperbaric oxygen(HBO against hepatic injury of septic rats under acute hypoxia of simulated high altitude.Methods Forty rats were randomly selected from 56 male healthy Sprague-Dawley(SD rats,and the acute hypoxia model was reproduced in the rats by keeping the rats in the low pressure oxygen chamber for 3 days to simulate acute hypoxia of 5000m altitude.The 40 acute hypoxic rats were then randomly divided into 5 groups(8 each: high altitude control group,high altitude sepsis(SEP group,high altitude SEP+HBO group,high altitude SEP+cefepime(CEF group and high altitude SEP+HBO+CEF group.Sepsis was reproduced by cecal ligation puncture(CLP in all the acute hypoxic rats except those in high altitude control group.The SEP rats were then treated with HBO(2 atmosphere absolute or/and CEF(50mg/kg,intraperitoneal injection.The remaining 16 rats were then randomly divided into plain control group and plain SEP group(8 each.All animals were sacrificed at 24h after modeling,the liver and blood samples were collected for biochemical and histopathological analysis.The aspartate aminotransferase(AST and alanine aminotransferase(ALT levels in blood samples,and the activity of superoxide(SOD and the contents of malondialdehyde(MDA were determined.Results The ALT level and MDA content increased significantly(P < 0.05 in high altitude control group(ALT 76.5±12.2 U/L,AST 204.4 11.5 U/L,MDA 1.18±0.11nmol/mg prot,SOD 59.5±6.6 U/mg prot compared with that in plain control group(ALT 57.0 6.7 U/L,AST 194.6±8.0 U/L,MDA 0.95±0.13nmol/mg prot,SOD 74.1±7.8 U/mg prot.The ALT and AST levels and MDA content increased significantly,while the SOD activity decreased significantly(P < 0.05 in high altitude SEP group(ALT 142.8±7.2 U/L,AST 307.5±11.3 U/L,MDA 1.75±0.21 nmol/mg prot,SOD 44.5±4.4 U/mg prot compared with that in plain SEP group(ALT 103.6±5.8 U/L,AST 218.6±11.0 U/L,MDA 1.38±0.14 nmol/mg prot,SOD 55.5±6.4 U

  3. A high-altitude balloon platform to measure regional carbon dioxide exchange from agricultural systems

    Science.gov (United States)

    Potosnak, M. J.; Pocs, M.; Bouche, A.; Roberts, K.; Goedde, C.; Beck-Winchatz, B.

    2014-12-01

    Biosphere-atmosphere exchanges of carbon dioxide are an important component of the global carbon cycle, and understanding current exchanges is crucial for predicting future uptake of anthropogenic carbon dioxide. Agricultural systems in the Midwestern United States cover a large area and have the potential to influence the future carbon budget of the United States. Biosphere-atmosphere exchanges of carbon dioxide are typically measured at the ecosystem level using the eddy covariance technique that covers a relatively small spatial area. Top-down approaches using a global network of carbon dioxide concentration measurements provide relatively coarse spatial information. High altitude balloons (HABs) are an inexpensive platform for sounding the vertical structure and composition of the atmosphere that can bridge the spatial gap between these two other techniques. The HAB platform will also complement new satellite measurements of carbon dioxide from the Orbiting Carbon Observatory-2. In the first-generation approach of the HAB technique, a single balloon is launched, and a vertical profile of carbon dioxide is recorded during the balloon's ascent. The balloon bursts between 11 and 14 km altitude, and a second profile of carbon dioxide is obtained during the descent. The difference in carbon dioxide concentration is computed as a function of altitude, which is converted to a molar difference by accounting for the temperature and pressure profile of the atmosphere, and then a flux is obtained by summing the molar differences and dividing by the time difference between ascent and descent. The second-generation approach uses two balloons and compares their ascent profiles. This is an improvement, since the balloon can travel 100 km due to the strength of the jet stream, making it difficult to compare ascent and descent profiles. The technique works best on days with a well-developed convective boundary layer. During peak growing season, uptake rates of -30 to -50

  4. High Capacity Radio over Fiber Transmission Links

    DEFF Research Database (Denmark)

    Caballero Jambrina, Antonio

    confirmed that this configuration provides high linear end-to-end transmission links and is capable of transparent transport of high spectral efficient modulation formats. Furthermore, this thesis introduces a novel approach for the generation and detection of high speed wireless signals in mm-wave......This thesis expands the state-of-the-art on the detection of high speed wireless signals using optics. Signal detection at speeds over 1 Gbps at carrier Radio Frequency (RF) ranging from 5 GHz to 100 GHz have been achieved by applying novel concepts on optical digital coherent receivers....... This achievement has satisfied the requirements on transmission robustness and high capacity of next generation hybrid optical fibre-wireless networks. One important contribution of this thesis is the novel concept of photonic downconversion with free-running pulsed laser source for phase modulated Radio...

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

    Directory of Open Access Journals (Sweden)

    Daniel Radiloff

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

  6. Development of Air Force aerial spray night operations: High altitude swath characterization

    Science.gov (United States)

    Multiple trials were conducted from 2006 to 2014 in an attempt to validate aerial spray efficacy at altitudes conducive to night spray operations using night vision goggles (NVG). Higher altitude application of pesticide (>400 feet above ground level [AGL]) suggested that effective vector control mi...

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

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    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

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

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    A. Korth

    2005-07-01

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

  9. A two century record of lead isotopes in high altitude Alpine snow and ice

    Science.gov (United States)

    Rosman, K. J. R.; Ly, C.; Van de Velde, K.; Boutron, C. F.

    2000-03-01

    A 140 m snow/ice core drilled at Mont Blanc, France, has been analysed for Pb isotopes, Pb and Ba concentrations. The 206Pb/ 207Pb ratio, which was measured by thermal ionisation mass spectrometry, decreased steadily from ˜1.18 about two centuries ago to ˜1.17 in 1960, then fell rapidly to ˜1.15 by 1968. Evidence of the Italian (Turin) isotopic lead experiment (IILE) was found in samples dated ˜1977 where the ratio dipped to 1.117. By the early 1990s it had returned to mid 1960s values. Large seasonal variations were found in Pb and Ba concentrations. Summer samples were associated with smooth changes in the 206Pb/ 207Pb ratio while larger fluctuations were encountered in winter which is consistent with a low altitude inversion near Mont Blanc in the winter and free transfer of pollutants from lower to higher altitudes at other times. A plot of 208Pb/ 207Pb versus 206Pb/ 207Pb ratios reveals three isotopic groupings, associated with the periods pre-1923, 1923-1968 and 1969-1991. In the first group, the isotopic composition is consistent with local mining, smelting and coal burning, while in the second, motor vehicle exhaust emissions dominate. In the third group, motor vehicle emissions also dominate but the Pb is even less radiogenic. During this period the IILE occurred and there was a reduction in the use of leaded gasoline in Europe. A comparison of the Mont Blanc and Summit (central Greenland) records shows they contain similar 206Pb/ 207Pb ratios between 1960 and 1968, although small differences in isotopic composition can be detected by also considering the 208Pb/ 207Pb ratio. However, after 1969 the two records diverge markedly, with the Greenland ratios being dominated by the highly radiogenic Mississippi valley-type Pb from the USA and with the Mont Blanc ratios moving to lower values particularly about the time of the IILE.

  10. Efficacy of ibuprofen on prevention of high altitude headache: A systematic review and meta-analysis.

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    Juan Xiong

    Full Text Available Ibuprofen is used to prevent high altitude headache (HAH but its efficacy remains controversial. We conducted a systematic review and meta-analysis of randomized, placebo-controlled trials (RCTs of ibuprofen for the prevention of HAH.Studies reporting efficacy of ibuprofen for prevention of HAH were identified by searching electronic databases (until December 2016. The primary outcome was the difference in incidence of HAH between ibuprofen and placebo groups. Risk ratios (RR were aggregated using a Mantel-Haenszel random effect model. Heterogeneity of included trials was assessed using the I2 statistics.In three randomized-controlled clinical trials involving 407 subjects, HAH occurred in 101 of 239 subjects (42% who received ibuprofen and 96 of 168 (57% who received placebo (RR = 0.79, 95% CI 0.66 to 0.96, Z = 2.43, P = 0.02, I2 = 0%. The absolute risk reduction (ARR was 15%. Number needed to treat (NNT to prevent HAH was 7. Similarly, The incidence of severe HAH was significant in the two groups (RR = 0.40, 95% CI 0.17 to 0.93, Z = 2.14, P = 0.03, I2 = 0%. Severe HAH occurred in 3% treated with ibuprofen and 10% with placebo. The ARR was 8%. NNT to prevent severe HAH was 13. Headache severity using a visual analogue scale was not different between ibuprofen and placebo. Similarly, the difference between the two groups in the change in SpO2 from baseline to altitude was not different. One included RCT reported one participant with black stools and three participants with stomach pain in the ibuprofen group, while seven participants reported stomach pain in the placebo group.Based on a limited number of studies ibuprofen seems efficacious for the prevention of HAH and may therefore represent an alternative for preventing HAH with acetazolamide or dexamethasone.

  11. Lung function and breathing pattern in subjects developing high altitude pulmonary edema.

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    Christian F Clarenbach

    Full Text Available INTRODUCTION: The purpose of the study was to comprehensively evaluate physiologic changes associated with development of high altitude pulmonary edema (HAPE. We tested whether changes in pulmonary function and breathing pattern would herald clinically overt HAPE at an early stage. METHODS: In 18 mountaineers, spirometry, diffusing capacity, nitrogen washout, nocturnal ventilation and pulse oximetry were recorded at 490 m and during 3 days after rapid ascent to 4559 m. Findings were compared among subjects developing HAPE and those remaining well (controls. RESULTS: In 8 subjects subsequently developing radiographically documented HAPE at 4559 m, median FVC declined to 82% of low altitude baseline while closing volume increased to 164% of baseline (P<0.05, both instances. In 10 controls, FVC decreased slightly (to 93% baseline, P<0.05 but significantly less than in subjects with HAPE and closing volume remained unchanged. Sniff nasal pressure was reduced in both subjects with and without subsequent HAPE. During nights at 4559 m, mean nocturnal oxygen saturation dropped to lower values while minute ventilation, the number of periodic breathing cycles and heart rate were higher (60%; 8.6 L/min; 97 cycles/h; 94 beats/min, respectively in subjects subsequently developing HAPE than in controls (73%; 5.1 L/min; 48 cycles/h; 79 beats/min; P<0.05 vs. HAPE, all instances. CONCLUSION: The results comprehensively represent the pattern of physiologic alterations that precede overt HAPE. The changes in lung function are consistent with reduced lung compliance and impaired gas exchange. Pronounced nocturnal hypoxemia, ventilatory control instability and sympathetic stimulation are further signs of subsequent overt HAPE.

  12. Population Trends of Central European Montane Birds Provide Evidence for Adverse Impacts of Climate Change on High-Altitude Species.

    Science.gov (United States)

    Flousek, Jiří; Telenský, Tomáš; Hanzelka, Jan; Reif, Jiří

    2015-01-01

    Climate change is among the most important global threats to biodiversity and mountain areas are supposed to be under especially high pressure. Although recent modelling studies suggest considerable future range contractions of montane species accompanied with increased extinction risk, data allowing to test actual population consequences of the observed climate changes and identifying traits associated to their adverse impacts are very scarce. To fill this knowledge gap, we estimated long-term population trends of montane birds from 1984 to 2011 in a central European mountain range, the Giant Mountains (Krkonoše), where significant warming occurred over this period. We then related the population trends to several species' traits related to the climate change effects. We found that the species breeding in various habitats at higher altitudes had more negative trends than species breeding at lower altitudes. We also found that the species moved upwards as a response to warming climate, and these altitudinal range shifts were associated with more positive population trends at lower altitudes than at higher altitudes. Moreover, long-distance migrants declined more than residents or species migrating for shorter distances. Taken together, these results indicate that the climate change, besides other possible environmental changes, already influences populations of montane birds with particularly adverse impacts on high-altitude species such as water pipit (Anthus spinoletta). It is evident that the alpine species, predicted to undergo serious climatically induced range contractions due to warming climate in the future, already started moving along this trajectory.

  13. Population Trends of Central European Montane Birds Provide Evidence for Adverse Impacts of Climate Change on High-Altitude Species.

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    Jiří Flousek

    Full Text Available Climate change is among the most important global threats to biodiversity and mountain areas are supposed to be under especially high pressure. Although recent modelling studies suggest considerable future range contractions of montane species accompanied with increased extinction risk, data allowing to test actual population consequences of the observed climate changes and identifying traits associated to their adverse impacts are very scarce. To fill this knowledge gap, we estimated long-term population trends of montane birds from 1984 to 2011 in a central European mountain range, the Giant Mountains (Krkonoše, where significant warming occurred over this period. We then related the population trends to several species' traits related to the climate change effects. We found that the species breeding in various habitats at higher altitudes had more negative trends than species breeding at lower altitudes. We also found that the species moved upwards as a response to warming climate, and these altitudinal range shifts were associated with more positive population trends at lower altitudes than at higher altitudes. Moreover, long-distance migrants declined more than residents or species migrating for shorter distances. Taken together, these results indicate that the climate change, besides other possible environmental changes, already influences populations of montane birds with particularly adverse impacts on high-altitude species such as water pipit (Anthus spinoletta. It is evident that the alpine species, predicted to undergo serious climatically induced range contractions due to warming climate in the future, already started moving along this trajectory.

  14. High-altitude multi-taskers: bumble bee food plant use broadens along an altitudinal productivity gradient.

    Science.gov (United States)

    Miller-Struttmann, Nicole E; Galen, Candace

    2014-12-01

    We use an extensive historical data set on bumble bee host choice collected almost 50 years ago by L. W. Macior (Melanderia 15:1-59, 1974) to examine how resource partitioning by bumble bees varies over a 2,700-m altitudinal gradient at four hierarchical scales: individual, colony, species and community. Bumble bee behavior, resource overlap between castes, and plant-bumble bee networks change with altitude in accordance with tightening temporal constraints on flowering and colony growth in alpine habitats. Individual bees were more likely to collect pollen from multiple sources at high altitude. Between-caste foraging niche overlap increased with altitude. Similarly, alpine forager networks were more highly nested than either subalpine or montane networks due to increased asymmetric specialization. However, interspecific resource partitioning showed a more complex spatial pattern with low niche overlap at intermediate altitude (subalpine) compared to montane (disturbed) and alpine (unproductive) sites. Results suggest that spatial variation in interspecific resource partitioning is driven by a shift in the behavior of long-tongued bumble bees. Long-tongued bumble bees specialized in the subalpine but generalized in montane and alpine zones. Our reanalysis of Macior's data shows that bumble bee behavior varies substantially with altitude influencing plant-bumble bee interaction networks. Results imply that pollination services to alpine host plants will change dramatically as subalpine species with unique foraging strategies move upward under global warming.

  15. Changes in labial capillary density on ascent to and descent from high altitude [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Edward Gilbert-Kawai

    2016-08-01

    Full Text Available Present knowledge of how the microcirculation is altered by prolonged exposure to hypoxia at high altitude is incomplete and modification of existing analytical techniques may improve our knowledge considerably. We set out to use a novel simplified method of measuring in vivo capillary density during an expedition to high altitude using a CytoCam incident dark field imaging video-microscope. The simplified method of data capture involved recording one-second images of the mucosal surface of the inner lip to reveal data about microvasculature density in ten individuals. This was done on ascent to, and descent from, high altitude. Analysis was conducted offline by two independent investigators blinded to the participant identity, testing conditions and the imaging site.  Additionally we monitored haemoglobin concentration and haematocrit data to see if we could support or refute mechanisms of altered density relating to vessel recruitment. Repeated sets of paired values were compared using Kruskall Wallis Analysis of Variance tests, whilst comparisons of values between sites was by related samples Wilcoxon Signed Rank Test. Correlation between different variables was performed using Spearman’s rank correlation coefficient, and concordance between analysing investigators using intra-class correlation coefficient. There was a significant increase in capillary density from London on ascent to high altitude; median capillaries per field of view area increased from 22.8 to 25.3 (p=0.021. There was a further increase in vessel density during the six weeks spent at altitude (25.3 to 32.5, p=0.017. Moreover, vessel density remained high on descent to Kathmandu (31.0 capillaries per field of view area, despite a significant decrease in haemoglobin concentration and haematocrit. Using a simplified technique, we have demonstrated an increase in capillary density on early and sustained exposure to hypobaric hypoxia at thigh altitude, and that this remains

  16. Investigation of Doppler Effects on high mobility OFDM-MIMO systems with the support of High Altitude Platforms (HAPs)

    Science.gov (United States)

    Mohammed, H. A.; Sibley, M. J. N.; Mather, P. J.

    2012-05-01

    The merging of Orthogonal Frequency Division Multiplexing (OFDM) with Multiple-input multiple-output (MIMO) is a promising mobile air interface solution for next generation wireless local area networks (WLANs) and 4G mobile cellular wireless systems. This paper details the design of a highly robust and efficient OFDM-MIMO system to support permanent accessibility and higher data rates to users moving at high speeds, such as users travelling on trains. It has high relevance for next generation wireless local area networks (WLANs) and 4G mobile cellular wireless systems. The paper begins with a comprehensive literature review focused on both technologies. This is followed by the modelling of the OFDM-MIMO physical layer based on Simulink/Matlab that takes into consideration high vehicular mobility. Then the entire system is simulated and analysed under different encoding and channel estimation algorithms. The use of High Altitude Platform system (HAPs) technology is considered and analysed.

  17. Endothelial dysfunction assessment by flow-mediated dilation in a high-altitude population

    Directory of Open Access Journals (Sweden)

    Calderón-Gerstein WS

    2017-11-01

    Full Text Available Walter S Calderón-Gerstein,1,2 Antonio López-Peña,3 Raúl Macha-Ramírez,3 Astrid Bruno-Huamán,2 Roxana Espejo-Ramos,2 Stephany Vílchez-Bravo,2 María Ramírez-Breña,2 Milagros Damián-Mucha,2 Adriana Matos-Mucha2 1Department of Medicine, National Hospital Ramiro Prialé Prialé, Essalud Junín, Huancayo, Junín, Peru; 2Faculty of Medicine, Continental University, Huancayo, Junín, Peru; 3Department of Radiology, National Hospital Ramiro Prialé Prialé, Essalud Junín, Huancayo, Junín, Peru Introduction: Endothelial function at high altitude has been measured only in populations that are genetically adapted to chronic hypoxia. The objective of this study was to evaluate endothelial dysfunction (ED in a nongenetically adapted high-altitude population of the Andes mountains, in Huancayo, Peru (3,250 meters above sea level.Methods: Participants included 61 patients: 28 cases and 33 controls. The cases were subjects with hypertension, diabetes mellitus, obesity, or a history of stroke or coronary artery disease. Flow-mediated vasodilation (FMD of the brachial artery was measured in the supine position, at noon, after 5 minutes of resting. The brachial artery was identified above the elbow. Its basal diameter was measured during diastole, and FMD was tested after 5 minutes of forearm ischemia. Intima–media complex in the right carotid artery was also determined. An increase in the artery’s baseline diameter <10% indicated a positive test. Endothelium-independent vasodilation was evaluated with sublingual nitrate administration. The intima–media complex in the right carotid artery was also measured.Results: 100% of diabetics had ED; ED was also found in 68.8% of obese individuals, 55% of hypertensive patients, and 46.5% of controls. Age, height, body mass index, and waist diameter were higher in the cases as compared with the controls. A total of 57.9% (n=11 of the cases and 45.2% (n=19 of the controls presented ED. Patients without ED

  18. Where the O2 goes to: preservation of human fetal oxygen delivery and consumption at high altitude.

    Science.gov (United States)

    Postigo, Lucrecia; Heredia, Gladys; Illsley, Nicholas P; Torricos, Tatiana; Dolan, Caitlin; Echalar, Lourdes; Tellez, Wilma; Maldonado, Ivan; Brimacombe, Michael; Balanza, Elfride; Vargas, Enrique; Zamudio, Stacy

    2009-02-01

    Fetal growth is decreased at high altitude (> 2700 m). We hypothesized that variation in fetal O(2) delivery might account for both the altitude effect and the relative preservation of fetal growth in multigenerational natives to high altitude. Participants were 168 women of European or Andean ancestry living at 3600 m or 400 m. Ancestry was genetically confirmed. Umbilical vein blood flow was measured using ultrasound and Doppler. Cord blood samples permitted calculation of fetal O(2) delivery and consumption. Andean fetuses had greater blood flow and oxygen delivery than Europeans and weighed more at birth, regardless of altitude (+208 g, P 200 g lower for Europeans at any given level of blood flow or O(2) delivery. Fetal haemoglobin concentration was increased, decreased, and the fetal / curve was left-shifted at 3600 m. Fetuses receiving less O(2) extracted more (r(2) = 0.35, P < 0.0001). These adaptations resulted in similar fetal O(2) delivery and consumption across all four groups. Increased umbilical venous O(2) delivery correlated with increased fetal O(2) consumption per kg weight (r(2) = 0.50, P < 0.0001). Blood flow (r(2) = 0.16, P < 0.001) and O(2) delivery (r(2) = 0.17, P < 0.001) correlated with birth weight at 3600 m, but not at 400 m (r(2) = 0.04, and 0.03, respectively). We concluded that the most pronounced difference at high altitude is reduced fetal blood flow, but fetal haematological adaptation and fetal capacity to increase O(2) extraction indicates that deficit in fetal oxygen delivery is unlikely to be causally associated with the altitude- and ancestry-related differences in fetal growth.

  19. Isotopic composition of dissolved inorganic nitrogen in high mountain lakes: variation with altitude in the Pyrenees

    Science.gov (United States)

    Bartrons, M.; Camarero, L.; Catalan, J.

    2010-05-01

    Nitrogen deposition in remote areas has increased, but the effect on ecosystems is still poorly understood. For aquatic systems, knowledge of the main processes driving the observed variation is limited, as is knowledge of how changes in nitrogen supply affect lake biogeochemical and food web processes. Differences in dissolved inorganic nitrogen (DIN) between lakes cannot be understood without considering catchment characteristics. In mountains, catchment features (e.g., thermal conditions, land cover) vary considerably with elevation. The isotopic composition of nitrogen (δ15N) is increasingly used to study aquatic ecosystem dynamics. Here we explore the variability of δ15N in DIN in high mountain lakes and show that environmental conditions that change with altitude can affect the isotopic ratio. We measured ammonium and nitrate δ15N values in atmospheric deposition, epilimnetic water, deep chlorophyll maximum water (DCMW) and sediment pore water (SPW) from eight mountain lakes in the Pyrenees, both above and below the treeline. Lakes showed relatively uniform δ15N-NH4+ values in SPW (2.2±1.6‰), with no variation corresponding to catchment or lake characteristics. We suggest that organic matter diagenesis under similar sediment conditions is responsible for the low variation between the lakes. In the water column, the range of δ15N values was larger for ammonium (-9.4‰ to 7.4‰) than for nitrate (-11.4‰ to -3.4‰), as a result of higher variation both between and within lakes (epilimnetic vs. DCM water). For both compounds part of the difference correlated with altitude or catchment features (e.g., scree proportion). Based on concentration, chemical and isotopic tendencies, we suggest that patterns arise from the distinct relative contributions of two types of water flow paths to the lakes: one from snowpack melting, with little soil interaction; and another highly influenced by soil conditions. The snow-type flow path contributes low DIN

  20. Niche segregation in high-altitude Himalayan chats (Aves, Turdidae): does morphology match ecology?

    Science.gov (United States)

    Landmann, Armin; Winding, Norbert

    1993-10-01

    We investigated patterns of habitat segregation and morphological differentiation in syntopic, closely related turdid birds of the alpine zone of the Central Himalayas. Discriminant function analysis of 19 habitat structure parameters and comparisons of additional habitat features revealed that the species were distributed along gradients of vegetation height and vegetation density. In addition, non-vegetational structural habitat features, like microrelief variability or the presence of rocks and boulders, had strong discriminating power. In terms of habitat preferences the species of the guild investigated formed three subsets: shrubbery species (Erithacus pectoralis, E. chrysaeus and Hodgsonius phoenicuroides), species preferring open areas with higher surface roughness (Phoenicurus frontalis, Chaimarrornis leucocephalus) and the high-altitude species Grandala coelicolor. Using discriminant function analysis of 20 characters, morphology was analysed in relation to microhabitat utilization and foraging behaviour. Species inhabiting patches of shrubby thickets and foraging mainly by pedal movements (E. pectoralis, E. chrysaeus and H. phoenicuroides) have in common short rounded wings with high wing loading and strong legs and feet. Species preferably foraging by aerial hawking or "perch and pounce" techniques in more open areas (P. frontalis, C. chaimarrornis, and to some extent E. cyanurus) have longer wings, shorter tarsi and long rictal bristles. Grandala proved to be well adpated for long-distance flights at high altitudes (long, pointed wings) and for pedal foraging. Overall our results fit the basic assumption of ecomorphological theory that morphological distance reflects ecological distance. The ordination of each species in morphological space closely matched its distribution in ecological space (microhabitat, foraging strategies). Striking associations of morphology with ecology were not only evident for single traits but were also found in

  1. Measurement Of Solar Radiation at New Delhi, High Altitude Observatory, Hanle and Maitri Antarctica

    Science.gov (United States)

    Jain, S. L.; Arya, B. C.

    The measurement of solar radiation plays an important role in climate and environmental change studies. The enhanced UV-B radiations at the ground level has the potential to cause adverse biological and environmental impacts. The amount of UV-B radiation at ground level depends on various temporal, spatial and meteorological factors such as time of the day, season, altitude, clouds, surface albedo, ozone, aerosols, etc. The risks for the human health, plant, animals and material are growing because of high exposition of the solar radiation which is caused by ozone depletion and other anthropogenic activities. A limited measurements have been made at high altitudes and Antarctica which are very crucial to inhabitants of these locations. In view of the above, measurements of solar radiation along with other parameters were carried out at Leh (34°77' N, 77°36' E), 3311 meter above mean sea level as well as at Indian Astronomical Observatory , Leh / Hanle ( Indian Institute of Astrophysics, Bangalore), Hanle (Mount Saraswati), Jammu and Kashmir (India) (32°43' N, 77°34' E), 4467 meter above mean sea level during July 13-31, 1999, June 2000 and July 2003 in a campaign mode. These measurements are first of its kind at a unique location well deep inside the troposphere as it happens to be one of the highest observatory in the world. The regular measurements are also being carried out at NPL, New Delhi(280 65^' N, 770 21^' E) and Maitri, Antarctica(70.440 S, 11.450 E). Also the data were collected during our voyage to Antarctica to cover latitudinal distribution of these parameters from Goa, India (15.240 N, 73.420 E) to Maitri, Antarctica (70.440 S, 11.450 E) using a highly sophisticated and microprocessor based compact hand held sun photometer consisting of five filter channels at 300, 305, 312, 940 and 1020 nm to measure solar radiation at all the sites. The measurements were used to derive total column ozone, water vapour and aerosol optical depth etc. The solar

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

    OpenAIRE

    Wing-Gaia, Stacie L.

    2014-01-01

    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 revie...

  3. Elevation of circulating miR-210-3p in high-altitude hypoxic environment

    Directory of Open Access Journals (Sweden)

    Yan eYan

    2016-03-01

    Full Text Available Background: The induction of miR-210-3p, a master hypoxamir, is a consistent feature of the hypoxic response in both normal and malignant cells. However, whether miR-210-3p acts as a circulating factor in response to a hypoxic environment remains unknown. The current study aimed to examine the effect of a high-altitude hypoxic environment on circulating miR-210-3p.Methods: We examined and compared the levels of miR-210-3p using TaqMan-based qRT-PCR in both peripheral blood cells and plasma from 84 ethnic Chinese Tibetans residing at 3560 m, 46 newly arrived migrant Han Chinese (Tibet Han and 82 Han Chinese residing at 8.9 m (Nanjing Han. Furthermore, we analyzed the correlations of miR-210-3p with hematological indices. Results: The relative concentrations of miR-210-3p to internal reference U6 in blood cells were significantly higher in the Tibet Han group (1.01±0.11, P<0.001 and in the Tibetan group (1.17±0.09, P<0.001 than in the Nanjing Han group (0.51±0.04. The absolute concentrations of plasma miR-210-3p were also markedly elevated in the Tibet Han group (503.54±42.95 fmol/L, P=0.004 and in the Tibetan group (557.78±39.84 fmol/L, P<0.001 compared to the Nanjing Han group (358.39±16.16 fmol/L. However, in both blood cells and plasma, miR-210-3p levels were not significantly different between the Tibet Han group and the Tibetan group (P=0.280, P=0.620, respectively. Plasma miR-210-3p concentrations were positively correlated with miR-210-3p levels in blood cells (r=0.192, P=0.005. Furthermore, miR-210-3p levels in both blood cells and plasma showed strong positive correlations with red blood cell counts and hemoglobin and hematocrit values. Conclusion: These data demonstrated, for the first time, that miR-210-3p might act as a circulating factor in response to hypoxic environments and could be associated with human adaptation to life at high altitudes.

  4. Urban ectopy in the mountains: Carbon monoxide exposure at high altitude

    Energy Technology Data Exchange (ETDEWEB)

    Leaf, D.A. [Univ. of California Medical Center, Los Angeles, CA (United States); Kleinman, M.T. [Univ. of California, Irvine, CA (United States)

    1996-07-01

    Environmental exposure to inhaled carbon monoxide (CO) increases coronary artery disease risk. Sudden cardiac death, a frequent manifestation of coronary artery disease, is usually a result of ventricular dysrhythmia. The effect of exposure to CO at sea level (CO/SL) and simulated high (2.1 km) altitudes (CO/HA) on the incidence of cardiac ectopy in subjects with coronary artery disease was investigated. A double-blind crossover study was conducted, with random-order assignment, and each subject served as his own control. Seventeen men with documented coronary artery disease and stable angina pectoris performed cardiopulmonary exercise stress tests after random exposure to either CO or clean air (CA) at sea level (CA/SL) or at a simulated 2.1-km high altitude (CA/HA). The individual CO and HA exposure conditions were each selected to reduce the percentage of oxygen saturation of the subjects arterial blood by 4%. Subjects blood carboxyhemoglobin levels were increased form an average of 0.62% after clean-air exposure to 3.91% of saturation after CO exposure. The percentage of oxygen saturation in arterial blood was reduced from a baseline level of 98% to approximately 94% after CO/SL or CA/HA and to approximately 90% after CO/HA. Compared with the CA/SL the average incidence of exercise-induced ventricular ectopy was approximately doubled after all exposures and a significant trend (p {le} .05) of increased ectopy with decreased oxygen saturation in arterial blood was observed. Yet, among subjects who were free from ectopy (n=11) on CA/SL, only 2 subjects developed ectopy after CO/HA. No episodes of ventricular tachycardia or fibrillation occurred. The findings indicated that exposure to increased levels of hypoxemia, resulting from hypoxic and/or CO exposures, increased the susceptibility to ventricular ectopy during exercise in individuals with stable angina pectoris; however, this risk was nominal for those without ectopy. 26 refs., 1 fig., 2 tabs.

  5. Dirrofilariasis in Shepherd Dogs of High Altitudes Areas in West Azerbaijan-Iran

    Directory of Open Access Journals (Sweden)

    Mojtaba Hadian

    2011-03-01

    Full Text Available Although the biology and ecology of the arthropod vectors are different, some factors, such as global warming, the increasing abundance of mosquitoes, the movement of domestic hosts, and the abundance of wild reservoirs, can act as favourable factors for the distribution of infections. The aim of this study was to determine the prevalence of Dirofilaria immitis infection in shepherd dogs living in the high altitude of mountainous area (i.e.1200 meters above the sea level. The study group was comprised of 160 shepherd dogs living in 4 mountainous regions (Targavar, Margavar, Kolshin and Hovarchin of west Azerbaijan where continuous movement of sheep and goat flocks resulted to have a little information about shepherd dogs in these regions. Additionally, arduous pathways have made impossible any access by car to some territories of these areas. The dogs were mostly mixed raced with different ages (from 1 to 10 years and sexes (male = 136, female = 24. Blood samples were collected from cephalic vein. Direct thin and thick blood smears and modified knott’s technique were used for detecting D.immitis microfilariae and other blood parasites. The results indicated that 40 (25 % of dogs were infected with D. immitis microfilariae. In examination of the dogs, no severe life threatening feature of the disease was diagnosed. There were no significant differences (P > 0.05 of Dirrofilaria infection among gender, age groups and geographical areas. High prevalence of asymptomatic Dirrofilariasis in shepherd dogs in this area highlights the need of controlling and preventive programs.

  6. Cluster observations of magnetic field fluctuations in the high-altitude cusp

    Directory of Open Access Journals (Sweden)

    K. Nykyri

    2004-07-01

    Full Text Available High-resolution (22 vector/s magnetic field data from Cluster FGM instrument are presented for the high-altitude cusp crossing on 17 March 2001. Despite the quiet solar wind conditions, the cusp was filled with magnetic field turbulence for much of the crossing. Large-scale fluctuations show some correlation between spacecraft but the higher frequency fluctuations show no correlation, indicating that the length scales of these waves are smaller than the spacecraft separation (500km. In many intervals, there are clear peaks in the wave power around the ion cyclotron frequency (~1Hz, and there is some evidence for waves at the first harmonic of this frequency. Both left- and right-hand polarised waves are found, with angles of propagation with respect to the ambient magnetic field that range from parallel to perpendicular. The regions of enhanced magnetic field fluctuations appear to be associated with plasma flows possibly originating from a lobe reconnection site. The most coherent, long lasting wave trains with frequencies close to local ion cyclotron frequency occur at a boundary between a sheared flow and a stagnant plasma.

  7. The High Altitude MMIC Sounding Radiometer on the GLOBAL HAWK: From Technology Development to Science Discovery

    Science.gov (United States)

    Brown, Shannon; Denning, Richard; Lambrigtsen, Bjorn; Lim, Boon; Tanabe, Jordan; Tanner, Alan

    2013-01-01

    This paper presents results from the High Altitude MMIC Sounding Radiometer (HAMSR) during three recent field campaigns on the Global Hawk Unmanned Ariel Vehicles (UAV), focusing on the enabling technology that led to unprecedented observations of significant weather phenomenon, such as thermodynamic evolution of the tropical cyclone core during rapid intensification and the high resolution three dimensional mapping of several atmospheric river events. HAMSR is a 25 channel cross-track scanning microwave sounder with channels near the 60 and 118 GHz oxygen lines and the 183 GHz water vapor line. HAMSR was originally designed and built at the Jet Propulsion Laboratory as a technology demonstrator in 1998. Subsequent to this, HAMSR participated in three NASA hurricane field campaigns, CAMEX-4, TCSP and NAMMA. Beginning in 2008, HAMSR was extensively upgraded to deploy on the NASA Global Hawk (GH) platform and serve as an asset to the NASA sub-orbital program. HAMSR has participated on the Global Hawk during the 2010 Genesis and Rapid Intensification (GRIP) campaign, the 2011 Winter Storms and Atmospheric Rivers (WISPAR) campaign and is currently participating in the NASA Ventures Hurricane and Severe Storm Sentinel (HS3) campaign (2011-2015).

  8. Plasma proteomic study in patients with high altitude pulmonary edema (HAPE

    Directory of Open Access Journals (Sweden)

    Yong-jun LUO

    2012-01-01

    Full Text Available Objective  To investigate the differential expressions of protein in the plasma proteome in patients suffering from high altitude pulmonary edema (HAPE and their implications. Methods  The plasmas of six HAPE patients and six healthy controls were studied. The high-abundant proteins in the plasma were removed. The low-abundant proteins in the plasma/serum were segregated by 2-DE. MALDI-TOF/MS was adopted to measure the peptide fingerprints after the differential protein spots were digested by enzymes. Comparison and analysis were made in the GenBank. Results  The immunoglobulin K1 light chain, serum transferrin protein precursor, and α-trypsin inhibitor heavy chain-related protein expressions were upregulated in HAPE patients compared with the control group. However the human fibrin glue coagulation protein 3 was down-regulated. Conclusion  The differential expression of the above four proteins in the plasma of HAPE patients may be related to the occurrence of HAPE and can be used as the target point for the prediction of HAPE.

  9. Scaling Features of High-Latitude Geomagnetic Field Fluctuations at Swarm Altitude: Impact of IMF Orientation

    Science.gov (United States)

    De Michelis, Paola; Consolini, Giuseppe; Tozzi, Roberta; Marcucci, Maria Federica

    2017-10-01

    This paper attempts to explore the statistical scaling features of high-latitude geomagnetic field fluctuations at Swarm altitude. Data for this study are low-resolution (1 Hz) magnetic data recorded by the vector field magnetometer on board Swarm A satellite over 1 year (from 15 April 2014 to 15 April 2015). The first- and second-order structure function scaling exponents and the degree of intermittency of the fluctuations of the intensity of the horizontal component of the magnetic field at high northern latitudes have been evaluated for different interplanetary magnetic field orientations in the GSM Y-Z plane and seasons. In the case of the first-order structure function scaling exponent, a comparison between the average spatial distributions of the obtained values and the statistical convection patterns obtained using a Super Dual Auroral Radar Network dynamic model (CS10 model) has been also considered. The obtained results support the idea that the knowledge of the scaling features of the geomagnetic field fluctuations can help in the characterization of the different ionospheric turbulence regimes of the medium crossed by Swarm A satellite. This study shows that different turbulent regimes of the geomagnetic field fluctuations exist in the regions characterized by a double-cell convection pattern and in those regions near the border of the convective structures.

  10. HAMP – the microwave package on the High Altitude and LOng range research aircraft (HALO

    Directory of Open Access Journals (Sweden)

    M. Mech

    2014-12-01

    Full Text Available An advanced package of microwave remote sensing instrumentation has been developed for the operation on the new German High Altitude LOng range research aircraft (HALO. The HALO Microwave Package, HAMP, consists of two nadir-looking instruments: a cloud radar at 36 GHz and a suite of passive microwave radiometers with 26 frequencies in different bands between 22.24 and 183.31 ± 12.5 GHz. We present a description of HAMP's instrumentation together with an illustration of its potential. To demonstrate this potential, synthetic measurements for the implemented passive microwave frequencies and the cloud radar based on cloud-resolving and radiative transfer model calculations were performed. These illustrate the advantage of HAMP's chosen frequency coverage, which allows for improved detection of hydrometeors both via the emission and scattering of radiation. Regression algorithms compare HAMP retrieval with standard satellite instruments from polar orbiters and show its advantages particularly for the lower atmosphere with a root-mean-square error reduced by 5 and 15% for temperature and humidity, respectively. HAMP's main advantage is the high spatial resolution of about 1 km, which is illustrated by first measurements from test flights. Together these qualities make it an exciting tool for gaining a better understanding of cloud processes, testing retrieval algorithms, defining future satellite instrument specifications, and validating platforms after they have been placed in orbit.

  11. Cosmic Ray Astrophysics using The High Altitude Water Cherenkov (HAWC Observatory in México

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    de la Fuente Eduardo

    2017-01-01

    Full Text Available The High-Altitude Water Cherenkov (HAWC TeV gamma–ray Observatory in México is ready to search and study gamma-ray emission regions, extremely high-energy cosmic-ray sources, and to identify transient phenomena. With a better Gamma/Hadron rejection method than other similar experiments, it will play a key role in triggering multi–wavelength and multi–messenger studies of active galaxies (AGN, gamma-ray bursts (GRB, supernova remnants (SNR, pulsar wind nebulae (PWN, Galactic Plane Sources, and Cosmic Ray Anisotropies. It has an instantaneous field-of-view of ∼2 str, equivalent to 15% of the whole sky and continuous operation (24 hours per day. The results obtained by HAWC–111 (111 detectors in operation were presented on the proceedings of the International Cosmic Ray Conference 2015 and in [1]. The results obtained by HAWC–300 (full operation are now under analysis and will be published in forthcoming papers starting in 2017 (see preliminary results on http://www.hawc-observatory.org/news/. Here we present the HAWC contributions on cosmic ray astrophysics via anisotropies studies, summarizing the HAWC detector and its upgrading by the installation of “outriggers”.

  12. Four point measurements of electrons using PEACE in the high-altitude cusp

    Directory of Open Access Journals (Sweden)

    M. G. G. T. Taylor

    Full Text Available We present examples of electron measurements from the PEACE instruments on the Cluster spacecraft in the high-latitude, high-altitude region of the Earth’s magnetosphere. Using electron density and energy spectra measurements, we examine two cases where the orbit of the Cluster tetrahedron is outbound over the northern hemisphere, in the afternoon sector approaching the magnetopause. Data from the magnetometer is also used to pinpoint the position of the spacecraft with respect to magnetospheric boundaries. This preliminary work specifically highlights the benefit of the multipoint measurement capability of the Cluster mission. In the first case, we observe a small-scale spatial structure within the magnetopause boundary layer. The Cluster spacecraft initially straddle a boundary, characterised by a discontinuous change in the plasma population, with a pair of spacecraft on either side. This is followed by a complete crossing of the boundary by all four spacecraft. In the second case, Cluster encounters an isolated region of higher energy electrons within the cusp. The characteristics of this region are consistent with a trapped boundary layer plasma sheet population on closed magnetospheric field lines. However, a boundary motion study indicates that this region convects past Cluster, a characteristic more consistent with open field lines. An interpretation of this event in terms of the motion of the cusp boundary region is presented.

    Key words. Magnetospheric physics (magnetopause, cusp and boundary layers; solar wind-magnetosphere interactions

  13. Cosmic Ray Astrophysics using The High Altitude Water Cherenkov (HAWC) Observatory in México

    Science.gov (United States)

    de la Fuente, Eduardo; Díaz-Vélez, Juan Carlos; Almada, Alberto Hernández; Nigoche-Netro, Alberto

    2017-06-01

    The High-Altitude Water Cherenkov (HAWC) TeV gamma-ray Observatory in México is ready to search and study gamma-ray emission regions, extremely high-energy cosmic-ray sources, and to identify transient phenomena. With a better Gamma/Hadron rejection method than other similar experiments, it will play a key role in triggering multi-wavelength and multi-messenger studies of active galaxies (AGN), gamma-ray bursts (GRB), supernova remnants (SNR), pulsar wind nebulae (PWN), Galactic Plane Sources, and Cosmic Ray Anisotropies. It has an instantaneous field-of-view of ˜2 str, equivalent to 15% of the whole sky and continuous operation (24 hours per day). The results obtained by HAWC-111 (111 detectors in operation) were presented on the proceedings of the International Cosmic Ray Conference 2015 and in [1]. The results obtained by HAWC-300 (full operation) are now under analysis and will be published in forthcoming papers starting in 2017 (see preliminary results on http://www.hawc-observatory.org/news/). Here we present the HAWC contributions on cosmic ray astrophysics via anisotropies studies, summarizing the HAWC detector and its upgrading by the installation of "outriggers".

  14. Four point measurements of electrons using PEACE in the high-altitude cusp

    Directory of Open Access Journals (Sweden)

    M. G. G. T. Taylor

    2001-09-01

    Full Text Available We present examples of electron measurements from the PEACE instruments on the Cluster spacecraft in the high-latitude, high-altitude region of the Earth’s magnetosphere. Using electron density and energy spectra measurements, we examine two cases where the orbit of the Cluster tetrahedron is outbound over the northern hemisphere, in the afternoon sector approaching the magnetopause. Data from the magnetometer is also used to pinpoint the position of the spacecraft with respect to magnetospheric boundaries. This preliminary work specifically highlights the benefit of the multipoint measurement capability of the Cluster mission. In the first case, we observe a small-scale spatial structure within the magnetopause boundary layer. The Cluster spacecraft initially straddle a boundary, characterised by a discontinuous change in the plasma population, with a pair of spacecraft on either side. This is followed by a complete crossing of the boundary by all four spacecraft. In the second case, Cluster encounters an isolated region of higher energy electrons within the cusp. The characteristics of this region are consistent with a trapped boundary layer plasma sheet population on closed magnetospheric field lines. However, a boundary motion study indicates that this region convects past Cluster, a characteristic more consistent with open field lines. An interpretation of this event in terms of the motion of the cusp boundary region is presented.Key words. Magnetospheric physics (magnetopause, cusp and boundary layers; solar wind-magnetosphere interactions

  15. Drivers for the development of an alluvial fan in a high-altitude glaciated catchment

    Science.gov (United States)

    Steiner, Jakob; Miles, Evan; Ragettli, Silvan

    2016-04-01

    Alluvial fans have channelization and deposition dynamics that are not entirely understood but can have considerable impact on the local hydrological regime. Especially in high-altitude and glaciated catchments they are rather rarely investigated. During glaciological field work between 2012 and 2015 in the Langtang catchment in the Nepalese Himalaya, such an alluvial fan of ca. 0.35 km2 (4000 m a.s.l.) at the end of a very small glaciated subcatchment (~9km2) was observed. The subcatchment is the site of one of the presumed largest landslides in earth's history, that likely happened 40 000 years ago with a volume of approximately 10^10 m3 and land surface erosion is well visible. During the recent Gorkha earthquake in April 2015 (M=7.8), additional sediments were mobilized along the steep valley slopes. From 6 sets of concurrent high-resolution satellite images and DEMs between 2006 and 2015 and an additional image from 1974 we derive the evolution in space and volume of this fan and identify main sources of sediment supply. Precipitation data from a nearby Automatic Weather Station provides insight into strong rainfall events. We can compare the growth of the fan in the period without significant earthquakes until April 2014 to the change after the seismic event (image from May 2015) and after the following Monsoon season (image from October 2015) and determine dominant drivers of erosion.

  16. High Speed Link Radiated Emission Reduction

    Science.gov (United States)

    Bisognin, P.; Pelissou, P.; Cissou, R.; Giniaux, M.; Vargas, O.

    2016-05-01

    To control the radiated emission of high-speed link and associated unit, the current approach is to implement overall harness shielding on cables bundles. This method is very efficient in the HF/ VHF (high frequency/ very high frequency) and UHF (ultra-high frequency) ranges when the overall harness shielding is properly bonded on EMC back-shell. Unfortunately, with the increasing frequency, the associated half wavelength matches with the size of Sub-D connector that is the case for the L band. Therefore, the unit connectors become the main source of interference emission. For the L-band and S-band, the current technology of EMC back-shell leaves thin aperture matched with the L band half wavelength and therefore, the shielding effectiveness is drastically reduced. In addition, overall harness shielding means significant increases of the harness mass.Airbus D&S Toulouse and Elancourt investigated a new solution to avoid the need of overall harness shielding. The objective is to procure EM (Electro-Magnetic) clean unit connected to cables bundles free of any overall harness shielding. The proposed solution is to implement EMC common mode filtering on signal interfaces directly on unit PCB as close as possible the unit connector.Airbus D&S Elancourt designed and manufactured eight mock-ups of LVDS (Low Voltage Differential Signaling) interface PCBs' with different solutions of filtering. After verification of the signal integrity, three mock-ups were retained (RC filter and two common mode choke coil) in addition to the reference one (without EMC filter).Airbus D&S Toulouse manufactured associated LVDS cable bundles and integrated the RX (Receiver) and TX (Transmitter) LVDS boards in shielded boxes.Then Airbus D&S performed radiated emission measurement of the LVDS links subassemblies (e.g. RX and TX boxes linked by LVDS cables) according to the standard test method. This paper presents the different tested solutions and main conclusions on the feasibility of such

  17. Adaptive Influence of Long Term High Altitude Residence on Spatial Working Memory: An fMRI Study

    Science.gov (United States)

    Yan, Xiaodan; Zhang, Jiaxing; Gong, Qiyong; Weng, Xuchu

    2011-01-01

    With an increasing population living at a high altitude (HA), the impact of HA residence on human cognitive function has raised concerns. We recruited two groups of college students with one group born and grew up at HA until early adulthood and the control group born and grew up at near sea level (SL); the two groups were matched at age, gender…

  18. Psychological and cognitive impairment of long-term migrators to high altitudes and the relationship to physiological and biochemical changes.

    Science.gov (United States)

    Gao, Y-X; Li, P; Jiang, C-H; Liu, C; Chen, Y; Chen, L; Ruan, H-Z; Gao, Y-Q

    2015-10-01

    The present study aimed to examine how long-term migration to high-altitude regions affects mentality and cognition, and the correlation with various physiological and biochemical changes. The WHO Neurobehavioral Core Test Battery, Raven's Standard Progressive Matrices (RSPM) and Pittsburgh Sleep Quality Index questionnaire were used to assess 141 young male subjects who lived in plain regions and 217 young male subjects who had migrated to a 4500 m high-altitude region and lived there for 1-5 years. Arterial oxyhemoglobin saturation, cerebral tissue oxygenation indices (TOIs), serum S100B and brain-derived neurotrophic factor (BDNF) were also measured. Long-term migrators to a high-altitude region exhibited exacerbated mood disorders, retarded color discrimination ability, decreased visual memory capacity, and impaired perceptual motor skill and motion stability. In addition, the migrators exhibited lower RSPM scores and lower sleep quality. Further analyses revealed significant correlations between sleep quality and cerebral TOIs, mood and sleep quality, mood and certain cognitive functions, mood and serum BDNF levels, and RSPM scores and serum S100B levels. Long-term living at high altitudes causes significant impairment of psychological and cognitive function. Cerebral hypoxic extent, sleep quality and biochemical dysfunction are major influencing factors. © 2014 EAN.

  19. Small mammalian herbivores as mediators of plant community dynamics in the high-altitude arid rangelands of Trans-Himalaya

    NARCIS (Netherlands)

    Bagchi, S.; Namgail, T.; Ritchie, M.E.

    2006-01-01

    The high-altitude rangelands of the Trans-Himalaya represent a grazing ecosystem which has supported an indigenous pastoral community for millennia alongside a diverse assemblage of wild herbivores including burrowing mammals (pikas and voles). Pastoralists consider the small mammals to cause

  20. Assessment of roughness length schemes implemented within the Noah land surface model for high-altitude regions

    NARCIS (Netherlands)

    Zheng, Donghai; van der Velde, R.; Su, Zhongbo; Booij, Martijn J.; Hoekstra, Arjen Ysbert; Wen, J.

    2014-01-01

    Current land surface models still have difficulties with producing reliable surface heat fluxes and skin temperature (Tsfc) estimates for high-altitude regions, which may be addressed via adequate parameterization of the roughness lengths for momentum (z0m) and heat (z0h) transfer. In this study,

  1. Carbon storage and long-term rate of accumulation in high-altitude Andean peatlands of Bolivia

    Science.gov (United States)

    J.A. Hribljan; D.J. Cooper; J. Sueltenfuss; E.C. Wolf; K.A. Heckman; Erik Lilleskov; R.A. Chimner

    2015-01-01

    The high-altitude (4,500+ m) Andean mountain range of north-western Bolivia contains many peatlands. Despite heavy grazing pressure and potential damage from climate change, little is known about these peatlands. Our objective was to quantify carbon pools, basal ages and long-term peat accumulation rates in peatlands in two areas of the arid puna ecoregion of Bolivia:...

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

    Science.gov (United States)

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

    2015-01-01

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

  3. Aerosol Chemistry over a High Altitude Station at Northeastern Himalayas, India

    Science.gov (United States)

    Chatterjee, Abhijit; Adak, Anandamay; Singh, Ajay K.; Srivastava, Manoj K.; Ghosh, Sanjay K.; Tiwari, Suresh; Devara, Panuganti C. S.; Raha, Sibaji

    2010-01-01

    Background There is an urgent need for an improved understanding of the sources, distributions and properties of atmospheric aerosol in order to control the atmospheric pollution over northeastern Himalayas where rising anthropogenic interferences from rapid urbanization and development is becoming an increasing concern. Methodology/Principal Findings An extensive aerosol sampling program was conducted in Darjeeling (altitude ∼2200 meter above sea level (masl), latitude 27°01′N and longitude 88°15′E), a high altitude station in northeastern Himalayas, during January–December 2005. Samples were collected using a respirable dust sampler and a fine dust sampler simultaneously. Ion chromatograph was used to analyze the water soluble ionic species of aerosol. The average concentrations of fine and coarse mode aerosol were found to be 29.5±20.8 µg m−3 and 19.6±11.1 µg m−3 respectively. Fine mode aerosol dominated during dry seasons and coarse mode aerosol dominated during monsoon. Nitrate existed as NH4NO3 in fine mode aerosol during winter and as NaNO3 in coarse mode aerosol during monsoon. Gas phase photochemical oxidation of SO2 during premonsoon and aqueous phase oxidation during winter and postmonsoon were the major pathways for the formation of SO42− in the atmosphere. Long range transport of dust aerosol from arid regions of western India was observed during premonsoon. The acidity of fine mode aerosol was higher in dry seasons compared to monsoon whereas the coarse mode acidity was higher in monsoon compared to dry seasons. Biomass burning, vehicular emissions and dust particles were the major types of aerosol from local and continental regions whereas sea salt particles were the major types of aerosol from marine source regions. Conclusions/Significance The year-long data presented in this paper provide substantial improvements to the heretofore poor knowledge regarding aerosol chemistry over northeastern Himalayas, and should be useful to

  4. Station-keeping of a high-altitude balloon with electric propulsion and wireless power transmission: A concept study

    Science.gov (United States)

    van Wynsberghe, Erinn; Turak, Ayse

    2016-11-01

    A stable, ultra long-duration high-altitude balloon (HAB) platform which can maintain stationary position would represent a new paradigm for telecommunications and high-altitude observation and transmission services, with greatly reduced cost and complexity compared to existing technologies including satellites, telecom towers, and unmanned aerial vehicles (UAVs). This contribution proposes a lightweight superpressure balloon platform for deployment to an altitude of 25 km. Electrohydrodynamic (EHD) thrusters are presented to maintain position by overcoming stratospheric winds. Critical to maintaining position is a continual supply of electrical power to operate the on-board propulsion system. One viable solution is to deliver power wirelessly to a high-altitude craft from a ground-based transmitter. Microwave energy, not heavily attenuated by the atmosphere, can be provided remotely from a ground-based generator (magnetron, klystron, etc.) and steered electrically with an antenna array (phased array) at a designated frequency (such as 2.45 or 5.8 GHz). A rectifying antenna ("rectenna") on the bottom of the balloon converts waves into direct current for on-board use. Preliminary mission architecture, energy requirements, and safety concerns for a proposed system are presented along with recommended future work.

  5. Altered Left Ventricular Geometry and Torsional Mechanics in High Altitude-Induced Pulmonary Hypertension: A Three-Dimensional Echocardiographic Study.

    Science.gov (United States)

    De Boeck, Bart W; Toma, Aurel; Kiencke, Stephanie; Dehnert, Christoph; Zügel, Stefanie; Siebenmann, Christoph; Auinger, Katja; Buser, Peter T; Maggiorini, Marco; Kaufmann, Beat A

    2018-01-03

    Changes in left ventricular (LV) torsion have been related to LV geometry in patients with concomitant long-standing myocardial disease or pulmonary hypertension (PH). We evaluated the effect of acute high altitude-induced isolated PH on LV geometry, volumes, systolic function, and torsional mechanics. Twenty-three volunteers were prospectively studied at low altitude and after the second (D3) and third night (D4) at high altitude (4,559 m). LV ejection fraction, multidirectional strains and torsion, LV volumes, sphericity, and eccentricity were derived by speckle-tracking on three-dimensional echocardiographic data sets. Pulmonary pressure was estimated from the transtricuspid pressure gradient (TRPG), LV preload from end-diastolic LV volume, and transmitral over mitral annular E velocity (E/e'). At high altitude, oxygen saturation decreased by 15%-20%, heart rate and cardiac index increased by 15%-20%, and TRPG increased from 21 ± 2 to 37 ± 9 mm Hg (P geometry and torsional mechanics. Copyright © 2017 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.

  6. Shared and unique signals of high-altitude adaptation in geographically distinct Tibetan populations.

    Directory of Open Access Journals (Sweden)

    Tana Wuren

    Full Text Available Recent studies have used a variety of analytical methods to identify genes targeted by selection in high-altitude populations located throughout the Tibetan Plateau. Despite differences in analytic strategies and sample location, hypoxia-related genes, including EPAS1 and EGLN1, were identified in multiple studies. By applying the same analytic methods to genome-wide SNP information used in our previous study of a Tibetan population (n = 31 from the township of Maduo, located in the northeastern corner of the Qinghai-Tibetan Plateau (4200 m, we have identified common targets of natural selection in a second geographically and linguistically distinct Tibetan population (n = 46 in the Tuo Tuo River township (4500 m. Our analyses provide evidence for natural selection based on iHS and XP-EHH signals in both populations at the p<0.02 significance level for EPAS1, EGLN1, HMOX2, and CYP17A1 and for PKLR, HFE, and HBB and HBG2, which have also been reported in other studies. We highlight differences (i.e., stratification and admixture in the two distinct Tibetan groups examined here and report selection candidate genes common to both groups. These findings should be considered in the prioritization of selection candidate genes in future genetic studies in Tibet.

  7. Wave particle interactions in the high-altitude polar cusp: a Cluster case study

    Directory of Open Access Journals (Sweden)

    B. Grison

    2005-12-01

    Full Text Available On 23 March 2002, the four Cluster spacecraft crossed in close configuration (~100 km separation the high-altitude (10 RE cusp region. During a large part of the crossing, the STAFF and EFW instruments have detected strong electromagnetic wave activity at low frequencies, especially when intense field-aligned proton fluxes were detected by the CIS/HIA instrument. In all likelihood, such fluxes correspond to newly-reconnected field lines. A focus on one of these ion injection periods highlights the interaction between waves and protons. The wave activity has been investigated using the k-filtering technique. Experimental dispersion relations have been built in the plasma frame for the two most energetic wave modes. Results show that kinetic Alfvén waves dominate the electromagnetic wave spectrum up to 1 Hz (in the spacecraft frame. Above 0.8 Hz, intense Bernstein waves are also observed. The close simultaneity observed between the wave and particle events is discussed as an evidence for local wave generation. A mechanism based on current instabilities is consistent with the observations of the kinetic Alfvén waves. A weak ion heating along the recently-opened field lines is also suggested from the examination of the ion distribution functions. During an injection event, a large plasma convection motion, indicative of a reconnection site location, is shown to be consistent with the velocity perturbation induced by the large-scale Alfvén wave simultaneously detected.

  8. A methodology to assess the effects of high altitude electromagnetic pulse (HEMP) on electric power systems

    Science.gov (United States)

    Taylor, E. R., Jr.; Eichler, C. H.; Barnes, P. R.

    Nuclear electromagnetic pulse (EMP) from high altitude nuclear detonations (HEMP) has the potential to seriously disrupt electric power systems. A methodology has been developed to assess the vulnerability of electric power systems to this phenomena for any specified nuclear burst scenario. The methodology is based on a structured approach whereby the power system is broken down into subsystems, functional groups, and circuits and devices. Vulnerability (likelihood of failure) is assessed for individual equipment (circuits and devices) for each nuclear burst scenario. These effects are then evaluated for their performance impact on successively higher system levels. This forms the input for classical load flow, short circuit and transient stability studies to evaluate system stability and survivability. Applicability of the assessment methodology is not dependent on the quality of component/equipment vulnerability data. Susceptibility of power equipment to HEMP damage may be determined by established technical analysis, by intepretation of equipment design and testing standards, and by laboratory testing. This paper has been written not only for the electric utility engineer, but also for experts in EMP who may not be knowledgeable in electric utility systems.

  9. Genome sequence of ground tit Pseudopodoces humilis and its adaptation to high altitude.

    Science.gov (United States)

    Cai, Qingle; Qian, Xiaoju; Lang, Yongshan; Luo, Yadan; Xu, Jiaohui; Pan, Shengkai; Hui, Yuanyuan; Gou, Caiyun; Cai, Yue; Hao, Meirong; Zhao, Jinyang; Wang, Songbo; Wang, Zhaobao; Zhang, Xinming; He, Rongjun; Liu, Jinchao; Luo, Longhai; Li, Yingrui; Wang, Jun

    2013-03-28

    The mechanism of high-altitude adaptation has been studied in certain mammals. However, in avian species like the ground tit Pseudopodoces humilis, the adaptation mechanism remains unclear. The phylogeny of the ground tit is also controversial. Using next generation sequencing technology, we generated and assembled a draft genome sequence of the ground tit. The assembly contained 1.04 Gb of sequence that covered 95.4% of the whole genome and had higher N50 values, at the level of both scaffolds and contigs, than other sequenced avian genomes. About 1.7 million SNPs were detected, 16,998 protein-coding genes were predicted and 7% of the genome was identified as repeat sequences. Comparisons between the ground tit genome and other avian genomes revealed a conserved genome structure and confirmed the phylogeny of ground tit as not belonging to the Corvidae family. Gene family expansion and positively selected gene analysis revealed genes that were related to cardiac function. Our findings contribute to our understanding of the adaptation of this species to extreme environmental living conditions. Our data and analysis contribute to the study of avian evolutionary history and provide new insights into the adaptation mechanisms to extreme conditions in animals.

  10. Seasonal accumulation of persistent organic pollutants on a high altitude glacier in the Eastern Alps.

    Science.gov (United States)

    Kirchgeorg, T; Dreyer, A; Gabrielli, P; Gabrieli, J; Thompson, L G; Barbante, C; Ebinghaus, R

    2016-11-01

    The seasonal accumulations of perfluorinated substances (PFAS), polybrominated diphenyl ethers (PBDE) and polycyclic aromatic hydrocarbons (PAH) were measured in a 10 m shallow firn core from a high altitude glacier at Mt. Ortles (Italy, 3830 m above sea level) in South Tyrol in the Italian Eastern Alps. The most abundant persistent organic pollutants of each group were perfluorobutanoic acid (PFBA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) (for PFASs); BDE 47, BDE 99, BDE 209 (for PBDEs) and phenanthrene (PHE), fluoranthene (FLA) and pyrene (PYR) (for PAHs). All compounds show different extents of seasonality, with higher accumulation during summer time compared to winter. This seasonal difference mainly reflects meteorological conditions with a low and stable atmospheric boundary layer in winter and strong convective activity in summer, transformation processes during the transport of chemicals and/or post-depositional alterations. Change in the composition of the water-soluble PFCAs demonstrates the influence of meltwater percolation through the firn layers. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. High altitude large-scale plasma waves in the equatorial electrojet at twilight

    Directory of Open Access Journals (Sweden)

    J. L. Chau

    2004-12-01

    Full Text Available Jicamarca radar observations of a new class of large-scale plasma waves in the equatorial electrojet (EEJ are presented and characterized. The study is based on long-term (204 days, single-baseline interferometry observations made in 2003 using a low-power radar mode, also known as JULIA mode, along with a few hours of observations made in an aperture synthesis imaging mode. The large-scale waves are found to occur at high altitudes in the E-region, mainly between 120 and 140km, around twilight (between 18:30 and 20:00 LT, with durations of a few minutes to an hour. In our long-term observations, these large-scale waves occur very often (between 1 and 5 out 10 nights, drift westward (~70 ms–1, exhibit very narrow spectral widths, and have both positive and negative Doppler shifts. The imaging results show that the large-scale waves occur along tilted bands that sweep westward and downward (~30–60ms–1, with a horizontal separation between bands of about 10–15km. The cause of the waves remains unknown.

    Key words. Ionosphere (ionospheric irregularities; equatorial ionosphere; instruments and techniques

  12. Differences in Hematological Traits between High- and Low-Altitude Lizards (Genus Phrynocephalus.

    Directory of Open Access Journals (Sweden)

    Songsong Lu

    Full Text Available Phrynocephalus erythrurus (Lacertilia: Agamidae is considered to be the highest living reptile in the world (about 4500-5000 m above sea level, whereas Phrynocephalus przewalskii inhabits low altitudes (about 1000-1500 m above sea level. Here, we report the differences in hematological traits between these two different Phrynocephalus species. Compared with P. przewalskii, the results indicated that P. erythrurus own higher oxygen carrying capacity by increasing red blood cell count (RBC, hemoglobin concentration ([Hb] and hematocrit (Hct and these elevations could promote oxygen carrying capacity without disadvantage of high viscosity. The lower partial pressure of oxygen in arterial blood (PaO2 of P. erythrurus did not cause the secondary alkalosis, which may be attributed to an efficient pulmonary system for oxygen (O2 loading. The elevated blood-O2 affinity in P. erythrurus may be achieved by increasing intrinsic O2 affinity of isoHbs and balancing the independent effects of potential heterotropic ligands. We detected one α-globin gene and three β-globin genes with 1 and 33 amino acid substitutions between these two species, respectively. Molecular dynamics simulation results showed that amino acids substitutions in β-globin chains could lead to the elimination of hydrogen bonds in T-state Hb models of P. erythrurus. Based on the present data, we suggest that P. erythrurus have evolved an efficient oxygen transport system under the unremitting hypobaric hypoxia.

  13. High altitude atmospheric discharges according to the runaway air breakdown mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Symbalisty, E.; Roussel-Dupre, R.; Yukhimuk, V.; Taranenko, Y.

    1997-04-01

    High altitude optical transients - red sprites, blue jets, and elves - are modeled in the context of the relativistic electron runaway air breakdown mechanism. These emissions are usually associated with large mesoscale convective systems (hereafter MCS). In thunderstorms cloud electrification proceeds over a time scale long enough to permit the conducting atmosphere above the cloud to polarize and short out the thunderstorm electric field. When a lightning strike rapidly neutralizes a cloud charge layer runaway driving fields can develop in the stratosphere and mesosphere. According to present simulations of the full runaway process the variety of observed optical emissions are due to the nature of the normal lightning event in the MCS that kick starts the runaway avalanche. In this paper the authors describe some details of the model, present the results of the evolution of the primary electron population, and summarize the initial conditions necessary for different types of discharges. Two companion papers present (a) the predicted optical, gamma ray, and radio emissions caused by these electrical discharges, and (b) the time evolution of the secondary electron population and its implications in terms of observables.

  14. [Phospholipids and structural modification of tissues and cell membranes for adaptation in high altitude mountains].

    Science.gov (United States)

    Iakovlev, V M; Vishnevskiĭ, A A; Shanazarov, A S

    2012-01-01

    The nature of the impact of physical factors of high altitudes (3200 m) on the lipids of tissues and membranes of animals was researched. It was established that the adaptation process in Wistar rats was followed by peroxide degradation and subsequent modification of the phospholipids' structure of tissues and microsomal membranes. Adaptive phospholipids reconstruction takes place in microsomal membranes in the tissues of the lungs, brain, liver and skeletal muscles. Together with this, the amount of phosphatidylinositol and phosphatidic acid accumulates, indicating that the hydrolysis of phosphatidylinositol-4, 5 biphosphate to diacylglycerol and secondary messenger--inositol triphosphate, occurs. A decrease in temperature adaptation (+10 degrees C) leads to a more noticeable shift in peroxide oxidation of lipids, phospholipid structure in the tissues and membranes rather than adaptation in thermoneutral conditions (+30 degrees C). Modification of lipid composition of tissues and cell membranes in the highlands obviously increases the adaptive capabilities of cells of the whole body: physical performance and resistance to hypoxia increases in animals.

  15. Estimates of Carbon Reservoirs in High-Altitude Wetlands in the Colombian Andes

    Directory of Open Access Journals (Sweden)

    Enrique Javier Peña

    2009-10-01

    Full Text Available The observed increase in emission of greenhouse gases, with attendant effects on global warming, have raised interests in identifying sources and sinks of carbon in the environment. Terrestrial carbon (C sequestration involves capture of atmospheric C through photosynthesis and storage in biota, soil and wetlands. Particularly, wetland systems function primarily as long-term reservoirs for atmospheric carbon dioxide (CO2 and as sources of atmospheric methane (CH4. The objective of this study was to evaluate the patterns of carbon reservoirs in two high-altitude wetlands in the central Andean mountain of Colombia. Carbon cycle in both systems is related mainly with the plant biomass dynamics from the littoral zone. Thus, total organic carbon concentrate an average up to 329 kg of N ha-1 and 125 kg of P ha-1 every year vs only 17 kg N ha-1 and 6 kg P ha-1 in the water column of the limnetic zone in the wetland, evidencing spatial differences in carbon concentrations for these types of ecosystems. Results revealed that these systems participate in the balance and sequestration of carbon in the Colombian Andes.

  16. HAVOC: High Altitude Venus Operational Concept - An Exploration Strategy for Venus

    Science.gov (United States)

    Arney, Dale; Jones, Chris

    2015-01-01

    The atmosphere of Venus is an exciting destination for both further scientific study and future human exploration. A lighter-than-air vehicle can carry either a host of instruments and probes, or a habitat and ascent vehicle for a crew of two astronauts to explore Venus for up to a month. The mission requires less time to complete than a crewed Mars mission, and the environment at 50 km is relatively benign, with similar pressure, density, gravity, and radiation protection to the surface of Earth. 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. Key technical challenges for the mission include performing the aerocapture maneuvers at Venus and Earth, inserting and inflating the airship at Venus, and protecting the solar panels and structure from the sulfuric acid in the atmosphere. With advances in technology and further refinement of the concept, missions to the Venusian atmosphere can expand humanity's future in space.

  17. Life history evolution and cellular mechanisms associated with increased size in high-altitude Drosophila.

    Science.gov (United States)

    Lack, Justin B; Yassin, Amir; Sprengelmeyer, Quentin D; Johanning, Evan J; David, Jean R; Pool, John E

    2016-08-01

    Understanding the physiological and genetic basis of growth and body size variation has wide-ranging implications, from cancer and metabolic disease to the genetics of complex traits. We examined the evolution of body and wing size in high-altitude Drosophila melanogaster from Ethiopia, flies with larger size than any previously known population. Specifically, we sought to identify life history characteristics and cellular mechanisms that may have facilitated size evolution. We found that the large-bodied Ethiopian flies laid significantly fewer but larger eggs relative to lowland, smaller-bodied Zambian flies. The highland flies were found to achieve larger size in a similar developmental period, potentially aided by a reproductive strategy favoring greater provisioning of fewer offspring. At the cellular level, cell proliferation was a strong contributor to wing size evolution, but both thorax and wing size increases involved important changes in cell size. Nuclear size measurements were consistent with elevated somatic ploidy as an important mechanism of body size evolution. We discuss the significance of these results for the genetic basis of evolutionary changes in body and wing size in Ethiopian D. melanogaster.

  18. Coronagraphic Imaging of Debris Disks from a High Altitude Balloon Platform

    Science.gov (United States)

    Unwin, Stephen C.; Traub, W. A.; Trauger, J. T.; Bryden, G.; Stuchlik, D. W.; Lillie, C. F.

    2012-05-01

    Direct imaging of exoplanets orbiting nearby stars is a major observational challenge, demanding high angular resolution and extremely high dynamic range close to the parent star. Such a system could image and characterize the atmospheres of exoplanets, and also observe exozodiacal dust within the exoplanetary system. The ultimate experiment requires a space-based platform, but demonstrating much of the needed technology as well as performing valuable measurements of circumstellar debris disks, can be done from a high-altitude balloon platform. In this paper, we show how progress in key technologies leads to a balloon experiment as a logical future step toward a space mission. The HCIT testbed has shown ultra-high contrast using small optics in a vacuum testbed. A recent ground-based experiment has demonstrated the ability to control three active optics in series - a lightweight controllable primary mirror, and two deformable mirrors - to achieve close to the best wavefront correction possible with large optics in an in-air testbed. We briefly describe the Wallops Arcsecond Pointer (WASP), which has had a very successful first flight, showing the capability of a balloon platform to stably point to the accuracy required for a coronagraph payload experiment. A balloon-borne coronagraph mission would incorporate all of these advances in an instrument that verifies each one in a space-like environment, and enabling forefront science. Such an experiment would be a step toward mitigating the technical risks of a major space-based exoplanet coronagraph. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. Copyright 2012. California Institute of Technology. Government sponsorship acknowledged.

  19. Stratified Bacterial Diversity along Physico-chemical Gradients in High-Altitude Modern Stromatolites.

    Science.gov (United States)

    Toneatti, Diego M; Albarracín, Virginia H; Flores, Maria R; Polerecky, Lubos; Farías, María E

    2017-01-01

    At an altitude of 3,570 m, the volcanic lake Socompa in the Argentinean Andes is presently the highest site where actively forming stromatolite-like structures have been reported. Interestingly, pigment and microsensor analyses performed through the different layers of the stromatolites (50 mm-deep) showed steep vertical gradients of light and oxygen, hydrogen sulfide and pH in the porewater. Given the relatively good characterization of these physico-chemical gradients, the aim of this follow-up work was to specifically address how the bacterial diversity stratified along the top six layers of the stromatolites which seems the most metabolically important and diversified zone of the whole microbial community. We herein discussed how, in only 7 mm, a drastic succession of metabolic adaptations occurred: i.e., microbial communities shift from a UV-high/oxic world to an IR-low/anoxic/high H2S environment which force stratification and metabolic specialization of the bacterial community, thus, modulating the chemical faces of the Socompa stromatolites. The oxic zone was dominated by Deinococcus sp. at top surface (0.3 mm), followed by a second layer of Coleofasciculus sp. (0.3 to ∼2 mm). Sequences from anoxygenic phototrophic Alphaproteobacteria, along with an increasing diversity of phyla including Bacteroidetes, Spirochaetes were found at middle layers 3 and 4. Deeper layers (5-7 mm) were mostly occupied by sulfate reducers of Deltaproteobacteria, Bacteroidetes and Firmicutes, next to a high diversity and equitable community of rare, unclassified and candidate phyla. This analysis showed how microbial communities stratified in a physicochemical vertical profile and according to the light source. It also gives an insight of which bacterial metabolic capabilities might operate and produce a microbial cooperative strategy to thrive in one of the most extreme environments on Earth.

  20. Microalgae community of the Huaytire wetland, an Andean high-altitude wetland in Peru

    Directory of Open Access Journals (Sweden)

    Gian Salazar-Torres

    Full Text Available AIM: The diversity and distribution of microalgae communities in a high-altitude (3,000 to 4,500 m a.s.l Andean wetland, regionally known as bofedal, were examined to assess seasonal and spatial patterns. METHODS: Samples were taken monthly from June to December, 2008 at 13 stations in the Huaytire wetland (16° 54’ S and 70° 20’ W, covering three areas (impacted by urban land use, impacted by camelid pasture, and non-impacted and three climatologically induced periods (ice-covered, ice-melt and ice-free. RESULTS: A total of 52 genera of algae were recorded. Diatoms were the predominant group in abundance and richness. We found a significantly higher abundance during the ice-melting period, when light exposure and runoff were intermediate, in comparison to the ice-covered (low light and flushing and ice-free (high light and low runoff periods. Microalgae abundance was significantly lower in the non-impacted area compared to the sites close to the urban area and to the camelid pastures. Alpha diversity ranged from 8 to 29 genera per sample. High genera exchange was observed throughout the wetland, showing a similar floristic composition (beta diversity = 4%. CONCLUSIONS: We found that diatoms were dominant and adapted to the extreme conditions of the Andean wetland, showing higher abundance during the ice-melt period and in the livestock area. Also, taxa richness was higher in the ice-melt period and in the most-impacted areas.

  1. Measurement of the energy spectrum of cosmic-ray induced neutrons aboard an ER-2 high-altitude airplane

    CERN Document Server

    Goldhagen, P E; Kniss, T; Reginatto, M; Singleterry, R C; Van Steveninck, W; Wilson, J W

    2002-01-01

    Crews working on present-day jet aircraft are a large occupationally exposed group with a relatively high average effective dose from galactic cosmic radiation. Crews of future high-speed commercial aircraft flying at higher altitudes would be even more exposed. To help reduce the significant uncertainties in calculations of such exposures, the atmospheric ionizing radiation (AIR) project, an international collaboration of 15 laboratories, made simultaneous radiation measurements with 14 instruments on five flights of a NASA ER-2 high-altitude aircraft. The primary AIR instrument was a highly sensitive extended-energy multisphere neutron spectrometer with lead and steel shells placed within the moderators of two of its 14 detectors to enhance response at high energies. Detector responses were calculated for neutrons and charged hadrons at energies up to 100 GeV using MCNPX. Neutron spectra were unfolded from the measured count rates using the new MAXED code. We have measured the cosmic-ray neutron spectrum (t...

  2. A new high altitude paleoclimate record from the first ice core drilled in the eastern European Alps: preliminary results

    Science.gov (United States)

    Gabrielli, P.; Barbante, C.; Carturan, L.; Davis, M. E.; Dalla Fontana, G.; Dinale, R.; Dragà, G.; Gabrieli, J.; Kehrwald, N. M.; Mair, V.; Mikhalenko, V.; Oeggl, K.; Schotterer, U.; Seppi, R.; Thompson, L. G.; Tonidandel, D.

    2012-12-01

    Low latitude ice cores offer unique and detailed paleoclimate information from high elevations. Multiple proxies synchronized within the same ice medium offer the possibility to precisely link past climate variations to changes in the surrounding ecosystems and human activities, providing a unique paleo-geographic perspective of the Earth system. However, as most of the accessible low latitude drilling sites have already been exploited and as glaciers are melting worldwide, it is difficult to identify ice fields that contain novel and intact ice core records. We drilled the first ice cores to bedrock in the eastern European Alps during autumn 2011. These cores were extracted from the Alto dell'Ortles glacier (3859 m, South Tyrol, Italy) and their length was up to 75 m. The firn-ice transition was found at ~30 m depth. Below the temperate firn portion, cold ice layers sitting on frozen bedrock still exist and represent remnants from the colder climate before ~1980 AD. Analysis of beta emissions and tritium indicate the well-known 1963 peak (originating from radioactive nuclear fallout) to be at 41 m depth. Together with a measured density profile, this allows us to estimate an average accumulation rate of ~ 850 mm of water equivalent per year during the last 50 years. This confirms this drilling site as one with the lowest snow accumulation rate in the Alps, potentially containing older ice than most of the other Alpine glaciers. Preliminary analyses reveal that the deep and cold ice layers of this glacier preserve clearly distinguishable annual variations in stable isotopes, dust and major ions that can be precisely dated. Alto dell'Ortles is the first low-accumulation alpine drilling site where both winter and summer layers can be clearly identified. Application of a conventional flow model and preliminary annual layer counting suggest that the high altitude records contained in these ice cores may span at least several centuries.

  3. Performance changes during a weeklong high-altitude alpine ski-racing training camp in lowlander young athletes.

    Science.gov (United States)

    Hydren, Jay R; Kraemer, William J; Volek, Jeff S; Dunn-Lewis, Courtenay; Comstock, Brett A; Szivak, Tunde K; Hooper, David R; Denegar, Craig R; Maresh, Carl M

    2013-04-01

    Thousands of youth athletes travel to high altitude to participate in lift-access alpine sports. The purpose of this study was to examine the impact of acute high-altitude exposure on balance, choice reaction time, power, quickness, flexibility, strength endurance, and V[Combining Dot Above]O2max in youth lowlander athletes during a weeklong preseason training camp in Summit County, CO, USA. Eleven youth ski racers (4 boys and 7 girls; age, 13.7 ± 0.5 years; height, 157.2 ± 12.6 cm; weight, 52.4 ± 6.8 kg) with 7.7 ± 2.2 skiing years of experience participated in baseline testing at 160 m one week before the camp and a set of daily tests in the morning and afternoon at 2,828 m and skied between 3,328 and 3,802 m during a 6-day camp. Balance and choice reaction time tests were stagnant or improved slightly during the first 3 days and then improved on days 4 and 6. Vertical jump, flexibility, T-agility test, and push-ups in 1 minute improved on day 6. The number of sit-ups in 1 minute did not improve, and scores on the multistage fitness test decreased 20.34%. There was no effect of Lake Louise acute mountain sickness (AMS) questionnaire scores on performance variables measured. Athletes sojourning to high altitude for ski camps can train on immediate ascent but should slowly increase training volume over the first 3 days. Athletes should expect improvements in balance and reaction time 3-6 days into acclimatization. Coaches and athletes should expect about 20% of youth lowlander athletes to have signs and symptoms of AMS during the first 3 days of altitude exposure for alpine lift access sports at altitudes of up to 3,800 m.

  4. Investigation of whole-brain white matter identifies altered water mobility in the pathogenesis of high-altitude headache

    OpenAIRE

    Lawley, Justin S; Oliver, Samuel J; Mullins, Paul G; Macdonald, Jamie H

    2013-01-01

    Elevated brain water is a common finding in individuals with severe forms of altitude illness. However, the location, nature, and a causative link between brain edema and symptoms of acute mountain sickness such as headache remains unknown. We examined indices of brain white matter water mobility in 13 participants after 2 and 10 hours in normoxia (21% O2) and hypoxia (12% O2) using magnetic resonance imaging. Using a whole-brain analysis (tract-based spatial statistics (TBSS)), mean diffusiv...

  5. The 2009 Space Science Component of UNH Project SMART and High School Students Building a High-Altitude Balloon Payload

    Science.gov (United States)

    Smith, C. W.; Broad, L.; Chen, L.; Farrugia, C. J.; Frederick-Frost, K.; Goelzer, S.; Kucharek, H.; Messeder, R.; Moebius, E.; Puhl-Quinn, P. A.; Torbert, R. B.

    2009-12-01

    For the past 19 years the University of New Hampshire has offered a unique research and education opportunity to motivated high-school students called Project SMART (Science and Mathematics Achievement through Research Training). The Space Science module is strongly research based. Students work in teams of two on real research projects carved from the research programs of the faculty. The projects are carefully chosen to match the abilities of the students. The students receive classes in basic physics as well as lectures in space science to help them with their work. This year the research included the analysis of magnetic reconnection observations and Crater FTE observation, both by the CLUSTER spacecraft, the building of Faraday cups for thermal ion measurements in our thermal vacuum facility, and analysis of the IBEX star sensor. In addition to this, the students work on one combined project and for the past several years this project has been the building of a payload for a high-altitude balloon. The students learn to integrate telemetry and GPS location hardware while they build several small experiments that they then fly to the upper reaches of the Earth's atmosphere. This year the payload included a small video camera and the payload flew to 96,000 feet, capturing images of weather patterns as well as the curvature of the Earth, thickness of the atmosphere, and black space. In addition to still photos, we will be showing 2- and 7-minute versions of the 90-minute flight video that include footage from peak altitude, the bursting of the balloon, and initial descent.

  6. GLE and Sub-GLE Redefinition in the Light of High-Altitude Polar Neutron Monitors

    Science.gov (United States)

    Poluianov, S. V.; Usoskin, I. G.; Mishev, A. L.; Shea, M. A.; Smart, D. F.

    2017-11-01

    The conventional definition of ground-level enhancement (GLE) events requires a detection of solar energetic particles (SEP) by at least two differently located neutron monitors. Some places are exceptionally well suitable for ground-based detection of SEP - high-elevation polar regions with negligible geomagnetic and reduced atmospheric energy/rigidity cutoffs. At present, there are two neutron-monitor stations in such locations on the Antarctic plateau: SOPO/SOPB (at Amundsen-Scott station, 2835 m elevation), and DOMC/DOMB (at Concordia station, 3233 m elevation). Since 2015, when the DOMC/DOMB station started continuous operation, a relatively weak SEP event that was not detected by sea-level neutron-monitor stations was registered by both SOPO/SOPB and DOMC/DOMB, and it was accordingly classified as a GLE. This would lead to a distortion of the homogeneity of the historic GLE list and the corresponding statistics. To address this issue, we propose to modify the GLE definition so that it maintains the homogeneity: A GLE event is registered when there are near-time coincident and statistically significant enhancements of the count rates of at least two differently located neutron monitors, including at least one neutron monitor near sea level and a corresponding enhancement in the proton flux measured by a space-borne instrument(s). Relatively weak SEP events registered only by high-altitude polar neutron monitors, but with no response from cosmic-ray stations at sea level, can be classified as sub-GLEs.

  7. First Light Achieved at the new Mt.Evans High Altitude Observatory

    Science.gov (United States)

    Stencel, R. E.

    1997-12-01

    During August 1997, first light images were obtained with the new Meyer Binocular Telescope, a twin 0.72 meter RC system, located at the Meyer- Womble Observatory atop 14,268 ft Mt.Evans, Colorado. The site is along a treeless high ridge which frequently enjoys laminar airflow and good seeing. The telescope and building also include thermal and airflow management systems for seeing optimization. Finally, a 5 element adaptive optics system that is being tested at Yerkes Observatory, should be able to correct the native seeing to nearly the limit of optical performance. For details on all of the above, please refer to my website: www.du.edu/ rstencel. The high altitude of Mt.Evans makes it ideal for mid-infrared studies, and we anticipate pursuing mid-IR imaging and spectroscopy from this site. Mark 2 of our TNTCAM (Klebe et al.-this meeting) is now in design stage, thanks to an NSF MRI grant. The spectrometer, TGIRS (Creech-Eakman et al. 1996 BAAS 28: 1372) has also achieved first light in the lab. We plan to use both at the new mountaintop facility. Another interesting feature of the new observatory is its photovoltaic energy supply for continuous power, sponsored in part by the Renewable Energy Trust, National Renewable Energy Lab and the Colorado Office of Energy Conservation. Denver University is interested in forming partnerships with other programs in order to make best use of this new resource for educational research in astronomy and astrophysics. This can include REU-style student summer visits, instrument testing and/or observational studies. I am pleased to acknowledge sponsorship by the Estate of William Herschel Womble, and the Meyer Foundation.

  8. Titan’s High Altitude South Polar (HASP) Stratospheric Ice Cloud as observed by Cassini CIRS

    Science.gov (United States)

    Anderson, Carrie; Nna-Mvondo, Delphine; Samuelson, Robert E.; Achterberg, Richard K.; Flasar, F. Michael; Jennings, Donald E.; Raulin, Francois

    2017-10-01

    During Cassini’s T112 flyby of Titan in the late southern fall season (July 2015), the Composite InfraRed Spectrometer (CIRS) made a startling discovery - a massive cloud system had developed throughout Titan’s mid stratosphere (~200 km) at high southern latitudes. The vertical distributions of intensity of this High-Altitude South Polar (HASP) stratospheric ice cloud system are at least an order of magnitude stronger than the CIRS-observed northern winter polar stratospheric cloud system [1]. The chemical composition of the HASP cloud is not identical to its northern winter counterpart, in that it exhibits different spectral characteristics. The HASP cloud is just one illustrative example demonstrating the rapidly changing conditions occurring in Titan’s south polar stratospheric region as Titan began its journey into southern winter. Such observed changes are contrary to the observed configuration as Titan’s northern polar stratosphere transitioned out of northern winter, which revealed a relatively slow decay of: 1) the cold polar stratospheric temperatures, 2) the strength of the polar vortex, and 3) the abundances in stratospheric organic gases and ices. We will discuss the physical and chemical characteristics of the CIRS-observed HASP mid stratospheric ice cloud system. Potential ice analog candidates obtained from thin film transmission spectra of co-condensed nitrile/hydrocarbon ice mixtures obtained with our SPECtroscopy of Titan-Related ice AnaLogs (SPECTRAL) chamber are used to support these analyses. [1] Anderson C. M. and Samuelson R. E. (2011) Icarus, 212, 762-778.

  9. Toward High Altitude Airship Ground-Based Boresight Calibration of Hyperspectral Pushbroom Imaging Sensors

    Directory of Open Access Journals (Sweden)

    Aiwu Zhang

    2015-12-01

    Full Text Available 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 linear pushbroom sensors on HAA having no three-axis stabilized platform. In order to address this problem, a new ground-based boresight calibration method is proposed. Firstly, a coordinate’s transformation model is developed for direct georeferencing (DG of the linear imaging sensor, and then the linear error equation is derived from it by using the Taylor expansion formula. Secondly, the boresight misalignments are worked out by using iterative least squares method with few ground control points (GCPs and ground-based side-scanning experiments. The proposed method is demonstrated by three sets of experiments: (i the stability and reliability of the method is verified through simulation-based experiments; (ii the boresight calibration is performed using ground-based experiments; and (iii the validation is done by applying on the orthorectification of the real hyperspectral pushbroom images from a HAA Earth observation payload system developed by our research team—“LanTianHao”. The test results show that the proposed boresight calibration approach significantly improves the quality of georeferencing by reducing the geometric distortions caused by boresight misalignments to the minimum level.

  10. Drivers of Bird Species Richness within Moist High-Altitude Grasslands in Eastern South Africa.

    Science.gov (United States)

    Maphisa, David H; Smit-Robinson, Hanneline; Underhill, Les G; Altwegg, Res

    2016-01-01

    Moist high-altitude grasslands in South Africa are renowned for high avifaunal diversity and are priority areas for conservation. Conservation management of these areas conflicts with management for other uses, such as intensive livestock agriculture, which requires annual burning and leads to heavy grazing. Recently the area has become target for water storage schemes and renewable electricity energy projects. There is therefore an urgent need to investigate environmental factors and habitat factors that affect bird species richness in order to optimise management of those areas set aside for conservation. A particularly good opportunity to study these issues arose at Ingula in the eastern South African high-altitude grasslands. An area that had been subject to intense grazing was bought by the national power utility that constructed a pumped storage scheme on part of the land and set aside the rest for bird conservation. Since the new management took over in 2005 the area has been mostly annually burned with relatively little grazing. The new management seeks scientific advice on how to maintain avian species richness of the study area. We collected bird occurrence and vegetation data along random transects between 2006 and 2010 to monitor the impact of the new management, and to study the effect of the habitat changes on bird species richness. To achieve these, we convert bird transect data to presence only data to investigate how bird species richness were related to key transect vegetation attributes under this new grassland management. First we used generalised linear mixed models, to examine changes in vegetation grass height and cover and between burned and unburned habitats. Secondly, we examined how total bird species richness varied across seasons and years. And finally we investigated which habitat vegetation attributes were correlated with species richness of a group of grassland depended bird species only. Transects that were burned showed a larger

  11. Isotopic composition of dissolved inorganic nitrogen in high mountain lakes: variation with altitude in the Pyrenees

    Directory of Open Access Journals (Sweden)

    M. Bartrons

    2010-05-01

    Full Text Available Nitrogen deposition in remote areas has increased, but the effect on ecosystems is still poorly understood. For aquatic systems, knowledge of the main processes driving the observed variation is limited, as is knowledge of how changes in nitrogen supply affect lake biogeochemical and food web processes. Differences in dissolved inorganic nitrogen (DIN between lakes cannot be understood without considering catchment characteristics. In mountains, catchment features (e.g., thermal conditions, land cover vary considerably with elevation. The isotopic composition of nitrogen (δ15N is increasingly used to study aquatic ecosystem dynamics. Here we explore the variability of δ15N in DIN in high mountain lakes and show that environmental conditions that change with altitude can affect the isotopic ratio.

    We measured ammonium and nitrate δ15N values in atmospheric deposition, epilimnetic water, deep chlorophyll maximum water (DCMW and sediment pore water (SPW from eight mountain lakes in the Pyrenees, both above and below the treeline. Lakes showed relatively uniform δ15N-NH4+ values in SPW (2.2±1.6‰, with no variation corresponding to catchment or lake characteristics. We suggest that organic matter diagenesis under similar sediment conditions is responsible for the low variation between the lakes.

    In the water column, the range of δ15N values was larger for ammonium (−9.4‰ to 7.4‰ than for nitrate (−11.4‰ to −3.4‰, as a result of higher variation both between and within lakes (epilimnetic vs. DCM water. For both compounds part of the difference correlated with altitude or catchment features (e.g., scree proportion. Based on concentration, chemical and isotopic tendencies, we suggest that patterns arise from the distinct relative contributions of two types of water flow paths to the lakes: one from snowpack melting, with little soil

  12. High-altitude CO2 Clouds On Mars: A View From MEx Observations, The LMD MGCM, And Convective Potential Calculations

    Science.gov (United States)

    Maattanen, Anni; Montmessin, F.; Gondet, B.; Hoffmann, H.; Scholten, F.; Gonzalez-Galindo, F.; Spiga, A.; Forget, F.; Hauber, E.; Bertaux, J.; Bibring, J.; Neukum, G.

    2010-10-01

    We will summarize 3.5 Martian years (Mars Years 27-30) of high-altitude CO2 cloud data from MEx/OMEGA and selected results from Mex/HRSC. The 3-year dataset shows that the equatorial cloud activity is centered around the northern summer solstice with a pause at the aphelion, and that their appearance is limited in latitude and longitude. HRSC-measured altitudes and cloud speeds provide a rare dataset for comparison with GCMs. A comparison with the LMD Mars Global Climate Model shows a good agreement between the model-predicted winds and those observed by the HRSC. The LMD-MGCM predicts a strong diurnal variation of temperature at the cloud observation altitudes due to the propagation of the diurnal thermal tide. The coldest temperatures in the near-equator cloud altitude range (60-85 km) are observed towards the end of the afternoon, whereas the warmest temperatures are found in the early morning hours. Most of the observed clouds are cirrus-type, filamented clouds, but some OMEGA-observed clouds exhibit round, clumpy structures that have been suggested to be of convective origin. We asses the plausibility of the hypothesis of mesospheric convection in light of observations and theoretical Convective Available Potential Energy calculations. Estimates of convective potential and vertical velocities based on observed cloud properties suggest that the convective clouds could most likely be clusters of smaller scale convective updrafts. SPICAM stellar occultations have revealed large supersaturations at high altitudes: to attain the estimated values of CAPE and vertical velocity, most probably only moderate deviations from saturation are required. Based on nucleation modeling, such deviations may imply cloud formation via heterogeneous nucleation onto small condensation nuclei.

  13. Hydrological differentiation and spatial distribution of high altitude wetlands in a semi-arid Andean region derived from satellite data

    OpenAIRE

    Otto, M.; Scherer, D; Richters, J.

    2011-01-01

    High Altitude Wetlands of the Andes (HAWA) belong to a unique type of wetland within the semi-arid high Andean region. Knowledge about HAWA has been derived mainly from studies at single sites within different parts of the Andes at only small time scales. On the one hand, HAWA depend on water provided by glacier streams, snow melt or precipitation. On the other hand, they are suspected to influence hydrology through water retention and veg...

  14. Combustion efficiency and altitude operational limits of three liquid hydrocarbon fuels having high volumetric energy content in a J33 single combustor

    Science.gov (United States)

    Stricker, Edward G

    1950-01-01

    Combustion efficiency and altitude operational limits were determined in a J33 single combustor for AN-F-58 fuel and three liquid hydrocarbon fuels having high volumetric energy content (decalin, tetralin, and monomethylnaphthalene) at simulated altitude and combustor inlet-air conditions. At the conditions investigated, the combustion efficiency for the four fuels generally decreased with an increase in volumetric energy content. The altitude operational limits for decalin and tetralin fuels were higher than for AN-F-58 fuel; monomethylnaphthalene fuel gave the lowest altitude operational limit.

  15. Long term picoplankton dynamics in a warm-monomictic, tropical high altitude lake

    Directory of Open Access Journals (Sweden)

    Alfonso LUGO VÁZQUEZ

    2009-08-01

    Full Text Available Long term analyses of the microbial loop, centred on the picoplankton dynamics, were carried out over a five-year (1998 to 2002 period in Lake Alchichica (Puebla, Mexico, a high altitude tropical athalassohaline lake. The hydrodynamics of the lake followed a warm-monomictic pattern with mixing at a minimum temperature during the early dry season while the stratification was pronounced in the late dry season and throughout the rainy season; anoxic conditions in the hypolimnion lasted <9 months. The annual mean concentrations of chlorophyll-a were below 4 μg L-1 in 1998, 1999 and 2001, however, 6.1 and 5.2 μg L-1 in 2000 and 2002, respectively. Total picoplankton, TPP, displayed a temporal pattern that followed the mixing-stratification cycle. The highest TPP values (the whole water column ≥5×106 cells mL-1 were found during mixing and early stratification (January-March. The minimum numbers were present during late stratification (October-November. The maximum TPP numbers were observed within the layer 0-20 m, which corresponded to the epilimnion during the stratification period. Neither the thermocline nor the deep chlorophyll maximum showed an elevated TPP concentration. In the hypolimnion, TPP numbers were low (frequently <1×106 cells mL-1 apparently as a result of the long period of anoxia. Notwithstanding autotrophic picoplankton (APP contributed even ≥30% of TPP (2001 to 2002; no significant correlation was found between TPP and chlorophyll-a.

  16. High Altitude Long Endurance Air Vehicle Analysis of Alternatives and Technology Requirements Development

    Science.gov (United States)

    Nickol, Craig L.; Guynn, Mark D.; Kohout, Lisa L.; Ozoroski, Thomas A.

    2007-01-01

    The objective of this study was to develop a variety of High Altitude Long Endurance (HALE) Unmanned Aerial Vehicle (UAV) conceptual designs for two operationally useful missions (hurricane science and communications relay) and compare their performance and cost characteristics. Sixteen potential HALE UAV configurations were initially developed, including heavier-than-air (HTA) and lighter-than-air (LTA) concepts with both consumable fuel and solar regenerative (SR) propulsion systems. Through an Analysis of Alternatives (AoA) down select process, the two leading consumable fuel configurations (one each from the HTA and LTA alternatives) and an HTA SR configuration were selected for further analysis. Cost effectiveness analysis of the consumable fuel configurations revealed that simply maximizing vehicle endurance can lead to a sub-optimum system solution. An LTA concept with a hybrid propulsion system (solar arrays and a hydrogen-air proton exchange membrane fuel cell) was found to have the best mission performance; however, an HTA diesel-fueled wing-body-tail configuration emerged as the preferred consumable fuel concept because of the large size and technical risk of the LTA concept. The baseline missions could not be performed by even the best HTA SR concept. Mission and SR technology trade studies were conducted to enhance understanding of the potential capabilities of such a vehicle. With near-term technology SR-powered HTA vehicles are limited to operation in favorable solar conditions, such as the long days and short nights of summer at higher latitudes. Energy storage system specific energy and solar cell efficiency were found to be the key technology areas for enhancing HTA SR performance.

  17. A high-altitude balloon platform for determining exchange of carbon dioxide over agricultural landscapes

    Science.gov (United States)

    Bouche, Angie; Beck-Winchatz, Bernhard; Potosnak, Mark J.

    2016-11-01

    The exchange of carbon dioxide between the terrestrial biosphere and the atmosphere is a key process in the global carbon cycle. Given emissions from fossil fuel combustion and the appropriation of net primary productivity by human activities, understanding the carbon dioxide exchange of cropland agroecosystems is critical for evaluating future trajectories of climate change. In addition, human manipulation of agroecosystems has been proposed as a technique of removing carbon dioxide from the atmosphere via practices such as no-tillage and cover crops. We propose a novel method of measuring the exchange of carbon dioxide over croplands using a high-altitude balloon (HAB) platform. The HAB methodology measures two sequential vertical profiles of carbon dioxide mixing ratio, and the surface exchange is calculated using a fixed-mass column approach. This methodology is relatively inexpensive, does not rely on any assumptions besides spatial homogeneity (no horizontal advection) and provides data over a spatial scale between stationary flux towers and satellite-based inversion calculations. The HAB methodology was employed during the 2014 and 2015 growing seasons in central Illinois, and the results are compared to satellite-based NDVI values and a flux tower located relatively near the launch site in Bondville, Illinois. These initial favorable results demonstrate the utility of the methodology for providing carbon dioxide exchange data over a large (10-100 km) spatial area. One drawback is its relatively limited temporal coverage. While recruiting citizen scientists to perform the launches could provide a more extensive dataset, the HAB methodology is not appropriate for providing estimates of net annual carbon dioxide exchange. Instead, a HAB dataset could provide an important check for upscaling flux tower results and verifying satellite-derived exchange estimates.

  18. Relationship between daily exposure to biomass fuel smoke and blood pressure in high-altitude Peru.

    Science.gov (United States)

    Burroughs Peña, Melissa; Romero, Karina M; Velazquez, Eric J; Davila-Roman, Victor G; Gilman, Robert H; Wise, Robert A; Miranda, J Jaime; Checkley, William

    2015-05-01

    Household air pollution from biomass fuel use affects 3 billion people worldwide; however, few studies have examined the relationship between biomass fuel use and blood pressure. We sought to determine if daily biomass fuel use was associated with elevated blood pressure in high altitude Peru and if this relationship was affected by lung function. We analyzed baseline information from a population-based cohort study of adults aged ≥ 35 years in Puno, Peru. Daily biomass fuel use was self-reported. We used multivariable regression models to examine the relationship between daily exposure to biomass fuel smoke and blood pressure outcomes. Interactions with sex and quartiles of forced vital capacity were conducted to evaluate for effect modification. Data from 1004 individuals (mean age, 55.3 years; 51.7% women) were included. We found an association between biomass fuel use with both prehypertension (adjusted relative risk ratio, 5.0; 95% confidence interval, 2.6-9.9) and hypertension (adjusted relative risk ratio, 3.5; 95% confidence interval, 1.7-7.0). Biomass fuel users had a higher systolic blood pressure (7.0 mm Hg; 95% confidence interval, 4.4-9.6) and a higher diastolic blood pressure (5.9 mm Hg; 95% confidence interval, 4.2-7.6) when compared with nonusers. We did not find interaction effects between daily biomass fuel use and sex or percent predicted forced vital capacity for either systolic blood pressure or diastolic blood pressure. Biomass fuel use was associated with a higher likelihood of having hypertension and higher blood pressure in Peru. Reducing exposure to household air pollution from biomass fuel use represents an opportunity for cardiovascular prevention. © 2015 American Heart Association, Inc.

  19. Adaptive modulation of adult brain gray and white matter to high altitude: structural MRI studies.

    Directory of Open Access Journals (Sweden)

    Jiaxing Zhang

    Full Text Available The aim of this study was to investigate brain structural alterations in adult immigrants who adapted to high altitude (HA. Voxel-based morphometry analysis of gray matter (GM volumes, surface-based analysis of cortical thickness, and Tract-Based Spatial Statistics analysis of white matter fractional anisotropy (FA based on MRI images were conducted on 16 adults (20-22 years who immigrated to the Qinghai-Tibet Plateau (2300-4400 m for 2 years. They had no chronic mountain sickness. Control group consisted of 16 matched sea level subjects. A battery of neuropsychological tests was also conducted. HA immigrants showed significantly decreased GM volumes in the right postcentral gyrus and right superior frontal gyrus, and increased GM volumes in the right middle frontal gyrus, right parahippocampal gyrus, right inferior and middle temporal gyri, bilateral inferior ventral pons, and right cerebellum crus1. While there was some divergence in the left hemisphere, surface-based patterns of GM changes in the right hemisphere resembled those seen for VBM analysis. FA changes were observed in multiple WM tracts. HA immigrants showed significant impairment in pulmonary function, increase in reaction time, and deficit in mental rotation. Parahippocampal and middle frontal GM volumes correlated with vital capacity. Superior frontal GM volume correlated with mental rotation and postcentral GM correlated with reaction time. Paracentral lobule and frontal FA correlated with mental rotation reaction time. There might be structural modifications occurred in the adult immigrants during adaptation to HA. The changes in GM may be related to impaired respiratory function and psychological deficits.

  20. Stratified bacterial diversity along physico-chemical gradients in high-altitude modern stromatolites.

    NARCIS (Netherlands)

    Toneatti, Diego M.; Albarracín, Virginia H.; Flores, M. Regina; Polerecky, L.; Farías, María E.

    2017-01-01

    At an altitude of 3,570 m, the volcanic lake Socompa in the Argentinean Andes is presently the highest site where actively forming stromatolite-like structures have been reported. Interestingly, pigment and microsensor analyses performed through the different layers of the stromatolites (50 mm-deep)

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

    African Journals Online (AJOL)

    PCRT

    2014-11-19

    Nov 19, 2014 ... per treatment group via cardiac puncture into lithium heparinized tubes on ice to separate plasma and ..... indicated lower RV hypertrophy and greater ascites mortality than low-altitude incubated chickens during the ..... Pathophysiology of heart/lung disorders: pulmonary hypertension syndrome in broiler.

  2. High-Altitude MMIC Sounding Radiometer for the Global Hawk Unmanned Aerial Vehicle

    Science.gov (United States)

    Brown, Shannon T.; Lim, Boon H.; Tanner, Alan B.; Tanabe, Jordan M.; Kangaslahti, Pekka P.; Gaier, Todd C.; Soria, Mary M.; Lambrigtsen, Bjorn H.; Denning, Richard F.; Stachnik, Robert A.

    2012-01-01

    Microwave imaging radiometers operating in the 50-183 GHz range for retrieving atmospheric temperature and water vapor profiles from airborne platforms have been limited in the spatial scales of atmospheric structures that are resolved not because of antenna aperture size, but because of high receiver noise masking the small variations that occur on small spatial scales. Atmospheric variability on short spatial and temporal scales (second/ km scale) is completely unresolved by existing microwave profilers. The solution was to integrate JPL-designed, high-frequency, low-noise-amplifier (LNA) technology into the High-Altitude MMIC Sounding Radiometer (HAMSR), which is an airborne microwave sounding radiometer, to lower the system noise by an order of magnitude to enable the instrument to resolve atmospheric variability on small spatial and temporal scales. HAMSR has eight sounding channels near the 60-GHz oxygen line complex, ten channels near the 118.75-GHz oxygen line, and seven channels near the 183.31-GHz water vapor line. The HAMSR receiver system consists of three heterodyne spectrometers covering the three bands. The antenna system consists of two back-to-back reflectors that rotate together at a programmable scan rate via a stepper motor. A single full rotation includes the swath below the aircraft followed by observations of ambient (roughly 0 C in flight) and heated (70 C) blackbody calibration targets located at the top of the rotation. A field-programmable gate array (FPGA) is used to read the digitized radiometer counts and receive the reflector position from the scan motor encoder, which are then sent to a microprocessor and packed into data files. The microprocessor additionally reads telemetry data from 40 onboard housekeeping channels (containing instrument temperatures), and receives packets from an onboard navigation unit, which provides GPS time and position as well as independent attitude information (e.g., heading, roll, pitch, and yaw). The raw

  3. Morphological and morphometric specializations of the lung of the Andean goose, Chloephaga melanoptera: A lifelong high-altitude resident.

    Directory of Open Access Journals (Sweden)

    John N Maina

    Full Text Available High altitude flight in rarefied, extremely cold and hypoxic air is a very challenging activity. Only a few species of birds can achieve it. Hitherto, the structure of the lungs of such birds has not been studied. This is because of the rarity of such species and the challenges of preparing well-fixed lung tissue. Here, it was posited that in addition to the now proven physiological adaptations, high altitude flying birds will also have acquired pulmonary structural adaptations that enable them to obtain the large amounts of oxygen (O2 needed for flight at high elevation, an environment where O2 levels are very low. The Andean goose (Chloephaga melanoptera normally resides at altitudes above 3000 meters and flies to elevations as high as 6000 meters where O2 becomes limiting. In this study, its lung was morphologically- and morphometrically investigated. It was found that structurally the lungs are exceptionally specialized for gas exchange. Atypically, the infundibulae are well-vascularized. The mass-specific volume of the lung (42.8 cm3.kg-1, the mass-specific respiratory surface area of the blood-gas (tissue barrier (96.5 cm2.g-1 and the mass-specific volume of the pulmonary capillary blood (7.44 cm3.kg-1 were some of the highest values so far reported in birds. The pulmonary structural specializations have generated a mass-specific total (overall pulmonary morphometric diffusing capacity of the lung for oxygen (DLo2 of 0.119 mlO2.sec-1.mbar-1.kg-1, a value that is among some of the highest ones in birds that have been studied. The adaptations of the lung of the Andean goose possibly produce the high O2 conductance needed to live and fly at high altitude.

  4. An EPAS1 haplotype is associated with high altitude polycythemia in male Han Chinese at the Qinghai-Tibetan plateau.

    Science.gov (United States)

    Chen, Yu; Jiang, Chunhua; Luo, Yongjun; Liu, Fuyu; Gao, Yuqi

    2014-12-01

    Hemoglobin concentration at high altitude is considered an important marker of high altitude adaptation, and native Tibetans in the Qinghai-Tibetan plateau show lower hemoglobin concentrations than Han people who have emigrated from plains areas. Genetic studies revealed that EPAS1 plays a key role in high altitude adaptation and is associated with the low hemoglobin concentration in Tibetans. Three single nucleotide polymorphisms (rs13419896, rs4953354, rs1868092) of noncoding regions in EPAS1 exhibited significantly different allele frequencies in the Tibetan and Han populations and were associated with low hemoglobin concentrations in Tibetans. To explore the hereditary basis of high altitude polycythemia (HAPC) and investigate the association between EPAS1 and HAPC in the Han population, these 3 single nucleotide polymorphisms were assessed in 318 male Han Chinese HAPC patients and 316 control subjects. Genotyping was performed by high resolution melting curve analysis. The G-G-G haplotype of rs13419896, rs4953354, and rs1868092 was significantly more frequent in HAPC patients than in control subjects, whereas no differences in the allele or genotype frequencies of the 3 single nucleotide polymorphisms were found between HAPC patients and control subjects. Moreover, genotypes of rs1868092 (AA) and rs4953354 (GG) that were not observed in the Chinese Han in the Beijing population were found at frequencies of 1.6% and 0.9%, respectively, in our study population of HAPC patients and control subjects. Carriers of this EPAS1 haplotype (G-G-G, rs13419896, rs4953354, and rs1868092) may have a higher risk for HAPC. These results may contribute to a better understanding of the pathogenesis of HAPC in the Han population. Copyright © 2014 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

  5. Convergent Evolution of Hemoglobin Function in High-Altitude Andean Waterfowl Involves Limited Parallelism at the Molecular Sequence Level.

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    Natarajan, Chandrasekhar; Projecto-Garcia, Joana; Moriyama, Hideaki; Weber, Roy E; Muñoz-Fuentes, Violeta; Green, Andy J; Kopuchian, Cecilia; Tubaro, Pablo L; Alza, Luis; Bulgarella, Mariana; Smith, Matthew M; Wilson, Robert E; Fago, Angela; McCracken, Kevin G; Storz, Jay F

    2015-12-01

    A fundamental question in evolutionary genetics concerns the extent to which adaptive phenotypic convergence is attributable to convergent or parallel changes at the molecular sequence level. Here we report a comparative analysis of hemoglobin (Hb) function in eight phylogenetically replicated pairs of high- and low-altitude waterfowl taxa to test for convergence in the oxygenation properties of Hb, and to assess the extent to which convergence in biochemical phenotype is attributable to repeated amino acid replacements. Functional experiments on native Hb variants and protein engineering experiments based on site-directed mutagenesis revealed the phenotypic effects of specific amino acid replacements that were responsible for convergent increases in Hb-O2 affinity in multiple high-altitude taxa. In six of the eight taxon pairs, high-altitude taxa evolved derived increases in Hb-O2 affinity that were caused by a combination of unique replacements, parallel replacements (involving identical-by-state variants with independent mutational origins in different lineages), and collateral replacements (involving shared, identical-by-descent variants derived via introgressive hybridization). In genome scans of nucleotide differentiation involving high- and low-altitude populations of three separate species, function-altering amino acid polymorphisms in the globin genes emerged as highly significant outliers, providing independent evidence for adaptive divergence in Hb function. The experimental results demonstrate that convergent changes in protein function can occur through multiple historical paths, and can involve multiple possible mutations. Most cases of convergence in Hb function did not involve parallel substitutions and most parallel substitutions did not affect Hb-O2 affinity, indicating that the repeatability of phenotypic evolution does not require parallelism at the molecular level.

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

    Science.gov (United States)

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

    2014-01-01

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

  7. Grappling the High Altitude for Safe Edible Bamboo Shoots with Rich Nutritional Attributes and Escaping Cyanogenic Toxicity

    Directory of Open Access Journals (Sweden)

    Sayanika Devi Waikhom

    2013-01-01

    Full Text Available Consumption of bamboo species with high level of total cyanogenic content (TCC in Asia by many ethnic groups is significantly associated with food poisoning and occasionally Konzo (a neurological disorder. Adequate characterization of edible bamboo species with low level of TCC and high nutritious attributes is required for consumer’s safety as well as for the conservation of the gene pool. Here, we employed morphological descriptors, atomic absorption spectrophotometer, RAPD, and trnL-F intergenic spacer to characterize 15 indigenous edible bamboo species of north-east India. The study indicates that morphologically and genetically evolved edible bamboo species having large and robust bamboo-shoot texture and growing at low altitude contain high level of TCC, low antioxidant properties, and low levels of beneficial macronutrients and micronutrients. Importantly, Dendrocalamus species are shown to be rich in TCC irrespective of the growing altitude while Bambusa species are found to have moderate level of TCC. The findings clearly demonstrated that Chimonobambusa callosa growing at high altitude represents safe edible bamboo species with nutritious attributes.

  8. Genome of Plant Maca (Lepidium meyenii) Illuminates Genomic Basis for High-Altitude Adaptation in the Central Andes.

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    Zhang, Jing; Tian, Yang; Yan, Liang; Zhang, Guanghui; Wang, Xiao; Zeng, Yan; Zhang, Jiajin; Ma, Xiao; Tan, Yuntao; Long, Ni; Wang, Yangzi; Ma, Yujin; He, Yuqi; Xue, Yu; Hao, Shumei; Yang, Shengchao; Wang, Wen; Zhang, Liangsheng; Dong, Yang; Chen, Wei; Sheng, Jun

    2016-07-06

    Maca (Lepidium meyenii Walp, 2n = 8x = 64), belonging to the Brassicaceae family, is an economic plant cultivated in the central Andes sierra in Peru (4000-4500 m). Considering that the rapid uplift of the central Andes occurred 5-10 million years ago (Ma), an evolutionary question arises regarding how plants such as maca acquire high-altitude adaptation within a short geological period. Here, we report the high-quality genome assembly of maca, in which two closely spaced maca-specific whole-genome duplications (WGDs; ∼6.7 Ma) were identified. Comparative genomic analysis between maca and closely related Brassicaceae species revealed expansions of maca genes and gene families involved in abiotic stress response, hormone signaling pathway, and secondary metabolite biosynthesis via WGDs. The retention and subsequent functional divergence of many duplicated genes may account for the morphological and physiological changes (i.e., small leaf shape and self-fertility) in maca in a high-altitude environment. In addition, some duplicated maca genes were identified with functions in morphological adaptation (i.e., LEAF CURLING RESPONSIVENESS) and abiotic stress response (i.e., GLYCINE-RICH RNA-BINDING PROTEINS and DNA-DAMAGE-REPAIR/TOLERATION 2) under positive selection. Collectively, the maca genome provides useful information to understand the important roles of WGDs in the high-altitude adaptation of plants in the Andes. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  9. Lidar Observations of Tropical High-altitude Cirrus Clouds: Results form Dual Wavelength Raman Lidar Measurements During the ALBATROSS Campaign 1996

    Science.gov (United States)

    Neuber, R.; Wegener, Alfred; Schrems, O.; McDermid, I. S.

    1997-01-01

    Results from dual wavelength Raman Lidar Observations of tropical high-altitude cirrus clouds are reported. Based on 107 hours of night-time measurements cirrus cloud were present in more than 50% of the observations at latitudes between 23.5 degress S and 23.5 degrees N and altitudes between 11 and 16km.

  10. A new Differential Optical Absorption Spectroscopy instrument to study atmospheric chemistry from a high-altitude unmanned aircraft

    Science.gov (United States)

    Stutz, Jochen; Werner, Bodo; Spolaor, Max; Scalone, Lisa; Festa, James; Tsai, Catalina; Cheung, Ross; Colosimo, Santo F.; Tricoli, Ugo; Raecke, Rasmus; Hossaini, Ryan; Chipperfield, Martyn P.; Feng, Wuhu; Gao, Ru-Shan; Hintsa, Eric J.; Elkins, James W.; Moore, Fred L.; Daube, Bruce; Pittman, Jasna; Wofsy, Steven; Pfeilsticker, Klaus

    2017-03-01

    Observations of atmospheric trace gases in the tropical upper troposphere (UT), tropical tropopause layer (TTL), and lower stratosphere (LS) require dedicated measurement platforms and instrumentation. Here we present a new limb-scanning Differential Optical Absorption Spectroscopy (DOAS) instrument developed for NASA's Global Hawk (GH) unmanned aerial system and deployed during the Airborne Tropical TRopopause EXperiment (ATTREX). The mini-DOAS system is designed for automatic operation under unpressurized and unheated conditions at 14-18 km altitude, collecting scattered sunlight in three wavelength windows: UV (301-387 nm), visible (410-525 nm), and near infrared (900-1700 nm). A telescope scanning unit allows selection of a viewing angle around the limb, as well as real-time correction of the aircraft pitch. Due to the high altitude, solar reference spectra are measured using diffusors and direct sunlight. The DOAS approach allows retrieval of slant column densities (SCDs) of O3, O4, NO2, and BrO with relative errors similar to other aircraft DOAS systems. Radiative transfer considerations show that the retrieval of trace gas mixing ratios from the observed SCD based on O4 observations, the most common approach for DOAS measurements, is inadequate for high-altitude observations. This is due to the frequent presence of low-altitude clouds, which shift the sensitivity of the O4 SCD into the lower atmosphere and make it highly dependent on cloud coverage. A newly developed technique that constrains the radiative transfer by comparing in situ and DOAS O3 observations overcomes this issue. Extensive sensitivity calculations show that the novel O3-scaling technique allows the retrieval of BrO and NO2 mixing ratios at high accuracies of 0.5 and 15 ppt, respectively. The BrO and NO2 mixing ratios and vertical profiles observed during ATTREX thus provide new insights into ozone and halogen chemistry in the UT, TTL, and LS.

  11. Elemental stoichiometry indicates predominant influence of potassium and phosphorus limitation on arbuscular mycorrhizal symbiosis in acidic soil at high altitude.

    Science.gov (United States)

    Khan, Mohammad Haneef; Meghvansi, Mukesh K; Gupta, Rajeev; Veer, Vijay

    2015-09-15

    The functioning of high-altitude agro-ecosystems is constrained by the harsh environmental conditions, such as low temperatures, acidic soil, and low nutrient supply. It is therefore imperative to investigate the site-specific ecological stoichiometry with respect to AM symbiosis in order to maximize the arbuscular mycorrhizal (AM) benefits for the plants in such ecosystems. Here, we assess the elemental stoichiometry of four Capsicum genotypes grown on acidic soil at high altitude in Arunachal Pradesh, India. Further, we try to identify the predominant resource limitations influencing the symbioses of different Capsicum genotypes with the AM fungi. Foliar and soil elemental stoichiometric relations of Capsicum genotypes were evaluated with arbuscular mycorrhizal (AM) colonization and occurrence under field conditions. AM fungal diversity in rhizosphere, was estimated through PCR-DGGE profiling. Results demonstrated that the symbiotic interaction of various Capsicum genotypes with the AM fungi in acidic soil was not prominent in the study site as evident from the low range of root colonization (21-43.67%). In addition, despite the rich availability of carbon in plant leaves as well as in soil, the carbon-for-phosphorus trade between AMF and plants appeared to be limited. Our results provide strong evidences of predominant influence of the potassium-limitation, in addition to phosphorus-limitation, on AM symbiosis with Capsicum in acidic soil at high altitude. We also conclude that the potassium should be considered in addition to carbon, nitrogen, and phosphorus in further studies investigating the stoichiometric relationships with the AMF symbioses in high altitude agro-ecosystems. Copyright © 2015 Elsevier GmbH. All rights reserved.

  12. Protective effect of total flavonoids of seabuckthorn (Hippophae rhamnoides) in simulated high-altitude polycythemia in rats.

    Science.gov (United States)

    Zhou, Ji-Yin; Zhou, Shi-Wen; Du, Xiao-Huang; Zeng, Sheng-Ya

    2012-09-28

    Seabuckthorn (Hippophae rhamnoides L.) has been used to treat high altitude diseases. The effects of five-week treatment with total flavonoids of seabuckthorn (35, 70, 140 mg/kg, ig) on cobalt chloride (5.5 mg/kg, ip)- and hypobaric chamber (simulating 5,000 m)-induced high-altitude polycythemia in rats were measured. Total flavonoids decreased red blood cell number, hemoglobin, hematocrit, mean corpuscular hemoglobin levels, span of red blood cell electrophoretic mobility, aggregation index of red blood cell, plasma viscosity, whole blood viscosity, and increased deformation index of red blood cell, erythropoietin level in serum. Total flavonoids increased pH, pO₂, Sp(O₂), pCO₂ levels in arterial blood, and increased Na⁺, HCO₃⁻, Cl⁻, but decreased K⁺ concentrations. Total flavonoids increased mean arterial pressure, left ventricular systolic pressure, end-diastolic pressure, maximal rate of rise and decrease, decreased heart rate and protected right ventricle morphology. Changes in hemodynamic, hematologic parameters, and erythropoietin content suggest that administration of total flavonoids from seabuckthorn may be useful in the prevention of high altitude polycythaemia in rats.

  13. Gene Co-Expression Network Analysis Unraveling Transcriptional Regulation of High-Altitude Adaptation of Tibetan Pig.

    Directory of Open Access Journals (Sweden)

    Cunling Jia

    Full Text Available Tibetan pigs have survived at high altitude for millennia and they have a suite of adaptive features to tolerate the hypoxic environment. However, the molecular mechanisms underlying the regulation of hypoxia-adaptive phenotypes have not been completely elucidated. In this study, we analyzed differentially expressed genes (DEGs, biological pathways and constructed co-expression regulation networks using whole-transcriptome microarrays from lung tissues of Tibetan and Duroc pigs both at high and low altitude. A total of 3,066 DEGs were identified and this list was over-represented for the ontology terms including metabolic process, catalytic activity, and KEGG pathway including metabolic pathway and PI3K-Akt signaling pathway. The regulatory (RIF and phenotypic (PIF impact factor analysis identified several known and several potentially novel regulators of hypoxia adaption, including: IKBKG, KLF6 and RBPJ (RIF1, SF3B1, EFEMP1, HOXB6 and ATF6 (RIF2. These findings provide new details of the regulatory architecture of hypoxia-adaptive genes and also insight into which genes may undergo epigenetic modification for further study in the high-altitude adaptation.

  14. Studies on the growth performance of different broiler strains at high altitude and evaluation of probiotic effect on their survivability

    Science.gov (United States)

    Kalia, Sahil; K. Bharti, Vijay; Gogoi, Deepak; Giri, Arup; Kumar, Bhuvnesh

    2017-01-01

    Identification of appropriate breeds of broilers and development of new feed additives is required for the development of poultry industry at high altitude. Therefore, this experiment was conducted first to identify the suitable broiler strain for this region. One week old chicks (150) from three broiler strains, i.e. Vencobb, RIR cross-bred, and Hubbard were randomly selected and divided equally into three groups. All the chicks were provided the same basal diet. The body weight gain and feed: gain responses were significantly (P  0.05) were observed in weight gain, feed intake, feed: gain, and water intake among the three groups, however, mortality from ascites and coccidiosis was reduced in probiotic treated groups. Hence, our results suggest that RIR cross-bred is suitable for rearing in high altitude regions and probiotic supplementation has no beneficial effects on production performance of broilers at high altitude. However, probiotic supplementation indicated lesser loss due to mortality