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Sample records for high altitude podophyllum

  1. Change in protein content during seed germination of a high altitude plant Podophyllum hexandrum Royle.

    PubMed

    Dogra, Vivek; Ahuja, Paramvir Singh; Sreenivasulu, Yelam

    2013-01-14

    Podophyllum hexandrum Royle (=Sinopodophyllum hexandrum) is a high-altitude medicinal plant exploited for its etoposides which are potential anticancer compounds. An effective, conventional propagation method is by seed. However, seed germination is erratic, and seedling survival is low. A marginal increase in Podophyllum seed germination was attained with organic solvents. In the present study an attempt was made to decipher the physiological and biochemical barriers in terms of change in proteins during seed germination of Podophyllum. Comparative 2-DE analysis between un-germinated (dormant) and germinating seeds revealed nearly 113 differentially expressed proteins, whereas Peptide Mass Fingerprint (PMF) analysis of 97 protein spots revealed appearance of 27 proteins, up-accumulation of 11 proteins, down-accumulation of 19 proteins and disappearance of 40 proteins with germination. Identified 59 proteins in the homology search were involved in metabolism (carbohydrate and amino acid metabolism; 20 proteins), ABA/GA signaling (17 proteins) and stress (15 proteins) related proteins. Seven proteins were with unknown function. Two-DE, and MS/MS analysis in conjunction with semi-quantitative RT-PCR data of cell wall hydrolyzing genes, revealed that in Podophyllum the radicle protrusion occurs might be because of the up-accumulation of cell wall hydrolases i.e. β-1, 3-glucanase and XET which weakens the thick walled micropylar endosperm.

  2. Cloning and functional characterization of β-1, 3-glucanase gene from Podophyllum hexandrum - a high altitude Himalayan plant.

    PubMed

    Dogra, Vivek; Sreenivasulu, Yelam

    2015-01-01

    Podophyllum hexandrum is a high-altitude medicinal plant exploited for its etoposides which are potential anticancer compounds. ß-1, 3-glucanase cDNA was cloned from the germinating seeds of Podophyllum (Ph-glucanase). Glucanases belong to pathogenesis related glycohydralase family of proteins, which also play an important role in endosperm weakening and testa rupture during seed germination. Analysis of cloned nucleotide sequence revealed Ph-glucanase with an open reading frame of 852bp encoding a protein of 283 amino acids with a molecular mass of 31kDa and pI of 4.39. In-silico structure prediction of Ph-glucanase showed homology with that of Hevea brasiliensis (3em5B). Structural stability and enhanced catalytic efficiency in harsh climatic conditions possibly due to the presence of glycosyl hydrolase motif (LGIVISESGWPSAG) and a connecting loop towards inner side and well exposed carbohydrate metabolism domain-COG5309, can readily hydrolyse cell wall sugar moieties. Seeds from the transgenic Arabidopsis plants over-expressing Ph-glucanase showed better germination performance against a wide range of temperatures and abscisic acid (ABA) stress. This can be attributed to the accumulation of Ph-glucanase at both transcript and protein levels during the seed germination in transgenic Arabidopsis. Results confirm that the cloned novel seed specific glucanase from a cold desert plant Podophyllum could be used for the manipulation of different plant species seeds against various harsh conditions.

  3. Re-analysis of protein data reveals the germination pathway and up accumulation mechanism of cell wall hydrolases during the radicle protrusion step of seed germination in Podophyllum hexandrum- a high altitude plant

    PubMed Central

    Dogra, Vivek; Bagler, Ganesh; Sreenivasulu, Yelam

    2015-01-01

    Podophyllum hexandrum Royle is an important high-altitude plant of Himalayas with immense medicinal value. Earlier, it was reported that the cell wall hydrolases were up accumulated during radicle protrusion step of Podophyllum seed germination. In the present study, Podophyllum seed Germination protein interaction Network (PGN) was constructed by using the differentially accumulated protein (DAP) data set of Podophyllum during the radicle protrusion step of seed germination, with reference to Arabidopsis protein–protein interaction network (AtPIN). The developed PGN is comprised of a giant cluster with 1028 proteins having 10,519 interactions and a few small clusters with relevant gene ontological signatures. In this analysis, a germination pathway related cluster which is also central to the topology and information dynamics of PGN was obtained with a set of 60 key proteins. Among these, eight proteins which are known to be involved in signaling, metabolism, protein modification, cell wall modification, and cell cycle regulation processes were found commonly highlighted in both the proteomic and interactome analysis. The systems-level analysis of PGN identified the key proteins involved in radicle protrusion step of seed germination in Podophyllum. PMID:26579141

  4. Podophyllotoxin content, above- and belowground biomass in relation to altitude in Podophyllum hexandrum populations from Kumaun region of the Indian Central Himalaya.

    PubMed

    Nadeem, M; Palni, L M S; Kumar, A; Nandi, S K

    2007-04-01

    The morphological features of Podophyllum hexandrum Royle, a 'critically endangered' medicinal herb and a source of podophyllotoxin, were studied in populations growing in different parts of the Kumaun region of the Indian Central Himalaya. Plant growth performance in terms of biomass accumulation and podopyllotoxin levels in the rhizomes collected from eleven natural populations (P1 to P11, altitude ranging from 2740 to 3350 m) were analyzed. Morphological features, e. g., plant height, stem diameter and leaf area were, in general, negatively correlated with an increase in the altitude. Maximum aboveground (8.46 g/individual) and belowground (48.18 g/individual) biomass values were recorded from a population (P9) at the lowest altitude (2740 m) and, in general, the species was found to perform better at the lower altitudes. The podophyllotoxin content of rhizomes ranged between 0.36-1.08% (on dry wt. basis) in different populations, and a positive correlation was observed between podophyllotoxin content and an increase in the altitude.

  5. High-Altitude Illness

    MedlinePlus

    ... high-altitude illness:Acute mountain sicknessHigh-altitude pulmonary edema (also called HAPE), which affects the lungsHigh-altitude cerebral edema (also called HACE), which affects the brainThese illnesses ...

  6. Athletes at High Altitude

    PubMed Central

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

    2016-01-01

    Context: Athletes at different skill levels perform strenuous physical activity at high altitude for a variety of reasons. Multiple team and endurance events are held at high altitude and may place athletes at increased risk for developing acute high altitude illness (AHAI). Training at high altitude has been a routine part of preparation for some of the high level athletes for a long time. There is a general belief that altitude training improves athletic performance for competitive and recreational athletes. Evidence Acquisition: A review of relevant publications between 1980 and 2015 was completed using PubMed and Google Scholar. Study Design: Clinical review. Level of Evidence: Level 3. Results: AHAI is a relatively uncommon and potentially serious condition among travelers to altitudes above 2500 m. The broad term AHAI includes several syndromes such as acute mountain sickness (AMS), high altitude pulmonary edema (HAPE), and high altitude cerebral edema (HACE). Athletes may be at higher risk for developing AHAI due to faster ascent and more vigorous exertion compared with nonathletes. Evidence regarding the effects of altitude training on athletic performance is weak. The natural live high, train low altitude training strategy may provide the best protocol for enhancing endurance performance in elite and subelite athletes. High altitude sports are generally safe for recreational athletes, but they should be aware of their individual risks. Conclusion: Individualized and appropriate acclimatization is an essential component of injury and illness prevention. PMID:26863894

  7. High Altitude Pilgrimage Medicine

    PubMed Central

    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

  8. High Altitude Medical Problems

    PubMed Central

    Hultgren, Herbert N.

    1979-01-01

    Increased travel to high altitude areas by mountaineers and nonclimbing tourists has emphasized the clinical problems associated with rapid ascent. Acute mountain sickness affects most sojourners at elevations above 10,000 feet. Symptoms are usually worse on the second or third day after arrival. Gradual ascent, spending one to three days at an intermediate altitude, and the use of acetazolamide (Diamox) will prevent or ameliorate symptoms in most instances. Serious and potentially fatal problems, such as high altitude pulmonary edema or cerebral edema, occur in approximately 0.5 percent to 1.0 percent of visitors to elevations above 10,000 feet—especially with heavy physical exertion on arrival, such as climbing or skiing. Early recognition, high flow oxygen therapy and prompt descent are crucially important in management. Our knowledge of the causes of these and other high altitude problems, such as retinal hemorrhage, systemic edema and pulmonary hypertension, is still incomplete. Even less is known of the effect of high altitudes on medical conditions common at sea level or on the action of commonly used drugs. ImagesFigure 2. PMID:483805

  9. Medicine at high altitude.

    PubMed

    Wright, Alex D

    2006-01-01

    Medicine at high altitude provides important insights into the acute and chronic effects of hypoxia. Acute mountain sickness (AMS) is a common syndrome occurring after acute ascent to over 2,500 m and is caused by increased capillary permeability. A number of factors have been identified that increase the risk of AMS, in particular exercise. Avoiding rapid ascent, undue exercise and the use of acetazolamide are useful preventative measures but severe symptoms may require oxygen, dexamethasone and descent. Acute mountain sickness is usually self-limiting but may progress into the serious syndromes of pulmonary and cerebral oedema. Acclimatisation and adaptation are important for workers and residents at high altitude and the improvement seen in maximum exercise has been incorporated into some training schedules for endurance athletes. Chronic and subacute high-altitude diseases largely result from polycythemia and pulmonary hypertension.

  10. High altitude diving depths.

    PubMed

    Paulev, Poul-Erik; Zubieta-Calleja, Gustavo

    2007-01-01

    In order to make any sea level dive table usable during high altitude diving, a new conversion factor is created. We introduce the standardized equivalent sea depth (SESD), which allows conversion of the actual lake diving depth (ALDD) to an equivalent sea dive depth. SESD is defined as the sea depth in meters or feet for a standardized sea dive, equivalent to a mountain lake dive at any altitude, such that [image omitted] [image omitted] [image omitted] Mountain lakes contain fresh water with a relative density that can be standardized to 1,000 kg m(-3), and sea water can likewise be standardized to a relative density of 1,033 kg m(-3), at the general gravity of 9.80665 m s(-2). The water density ratio (1,000/1,033) refers to the fresh lake water and the standardized sea water densities. Following calculation of the SESD factor, we recommend the use of our simplified diving table or any acceptable sea level dive table with two fundamental guidelines: 1. The classical decompression stages (30, 20, and 10 feet or 9, 6, and 3 m) are corrected to the altitude lake level, dividing the stage depth by the SESD factor. 2. Likewise, the lake ascent rate during diving is equal to the sea ascent rate divided by the SESD factor.

  11. Cardiovascular medicine at high altitude.

    PubMed

    Whayne, Thomas F

    2014-07-01

    Altitude physiology began with Paul Bert in 1878. Chronic mountain sickness (CMS) was defined by Carlos Monge in the 1940s in the Peruvian Andes as consisting of excess polycythemia. Hurtado et al performed studies in the Peruvian Andes in the 1950s to 1960s which defined acclimatization in healthy altitude natives, including polycythemia, moderate pulmonary hypertension, and low systemic blood pressure (BP). Electrocardiographic changes of right ventricular hypertrophy (RVH) were noted. Acclimatization of newcomers to altitude involves hyperventilation stimulated by hypoxia and is usually benign. Acute mountain sickness (AMS) in travelers to altitude is characterized by hypoxia-induced anorexia, dyspnea, headache, insomnia, and nausea. The extremes of AMS are high-altitude cerebral edema and high-altitude pulmonary edema. The susceptible high-altitude resident can lose their tolerance to altitude and develop CMS, also referred to as Monge disease. The CMS includes extreme polycythemia, severe RVH, excess pulmonary hypertension, low systemic BP, arterial oxygen desaturation, and hypoventilation.

  12. Molecular characterization and marker based chemotaxonomic studies of Podophyllum hexandrum Royle.

    PubMed

    Sultan, Phalisteen; Shawl, A S; Rehman, Suriya; Ahmed, S Fayaz; Ramteke, P W

    2010-06-01

    Detailed chemical studies and RAPD analysis were done in different populations of Podophyllum hexandrum collected from high altitude regions of North Western Himalayas. Random amplified polymorphic DNA (RAPD) analysis revealed a high degree of genetic diversity among the 12 collected accessions, attributed to their geographical and climatic conditions. HPLC analysis also revealed variation in the concentration of two major marker compounds which lead to the identification of a chemotype. The study demonstrated that RAPD and chemical markers are very useful tools to compare the genetic relationship and pattern of variation among such prioritized and endangered medicinal plants.

  13. Brain Food at High Altitude.

    PubMed

    Jain, Vishal

    2016-01-01

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

  14. Infectious Diseases at High Altitude.

    PubMed

    Basnyat, Buddha; Starling, Jennifer M

    2015-08-01

    Travel to elevations above 2,500 m is an increasingly common activity undertaken by a diverse population of individuals. These may be trekkers, climbers, miners in high-altitude sites in South America, and more recently, soldiers deployed for high-altitude duty in remote areas of the world. What is also being increasingly recognized is the plight of the millions of pilgrims, many with comorbidities, who annually ascend to high-altitude sacred areas. There are also 400 million people who reside permanently in high mountain ranges, which cover one-fifth of the Earth's surface. Many of these high-altitude areas are in developing countries, for example, the Himalayan range in South Asia. Although high-altitude areas may not harbor any specific infectious disease agents, it is important to know about the pathogens encountered in the mountains to be better able to help both the ill sojourner and the native high-altitude dweller. Often the same pathogens prevalent in the surrounding lowlands are found at high altitude, but various factors such as immunomodulation, hypoxia, poor physiological adaptation, and harsh environmental stressors at high altitude may enhance susceptibility to these pathogens. Against this background, various gastrointestinal, respiratory, dermatological, neurological, and other infections encountered at high altitude are discussed.

  15. High Altitude Dermatology.

    PubMed

    Singh, Lt Col G K

    2017-01-01

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

  16. High Altitude Dermatology

    PubMed Central

    Singh, Lt. Col. G K

    2017-01-01

    Approximately, 140 million people worldwide live permanently at high altitudes (HAs) and approximately another 40 million people travel to HA area (HAA) every year for reasons of occupation, sports or recreation. In India, whole of Ladakh region, part of Northwest Kashmir, Northern part of Sikkim and Tenga valley of Arunachal are considered inhabited areas of HAA. The low quantity of oxygen, high exposure of ultraviolet (UV) light, very low humidity, extreme subzero temperature in winter, high wind velocity, make this region difficult for lowlanders as well as for tourists. Acute mountain sickness, HA pulmonary edema, HA cerebral edema, and thromboembolic conditions are known to occur in HA. However, enough knowledge has not been shared on dermatoses peculiar to this region. Xerosis, UV-related skin disorders (tanning, photomelanosis, acute and chronic sunburn, polymorphic light eruption, chronic actinic dermatitis, actinic cheilitis, etc.), cold injuries (frostbite, chilblains, acrocyanosis, erythrocyanosis, etc.) nail changes (koilonychias), airborne contact dermatitis, insect bite reaction, and skin carcinoma (basal cell carcinomas, squamous cell carcinomas, and also rarely malignant melanoma) are the dermatoses seen in HAAs. Early diagnosis and knowledge of HA dermatoses may prevent serious consequences of disease and improve the quality of life for the visitors as well as for native of the place. PMID:28216727

  17. High altitude reconnaissance aircraft

    NASA Technical Reports Server (NTRS)

    Yazdo, Renee Anna; Moller, David

    1990-01-01

    At the equator the ozone layer ranges from 65,000 to 130,000 plus feet, which is beyond the capabilities of the ER-2, NASA's current high altitude reconnaissance aircraft. The Universities Space Research Association, in cooperation with NASA, is sponsoring an undergraduate program which is geared to designing an aircraft that can study the ozone layer at the equator. This aircraft must be able to cruise at 130,000 feet for six hours at Mach 0.7, while carrying 3,000 lbs. of payload. In addition, the aircraft must have a minimum range of 6,000 miles. In consideration of the novel nature of this project, the pilot must be able to take control in the event of unforeseen difficulties. Three aircraft configurations were determined to be the most suitable - a joined-wing, a biplane, and a twin-boom conventional airplane. The performance of each configuration was analyzed to investigate the feasibility of the project.

  18. High Altitude Cerebral Edema

    DTIC Science & Technology

    1986-03-01

    English literature and Hultgren et al (3.1) described four more cases of HAPE within the next year. In 1960, Chiodi (5) first reported on a Peruvian...altitude and treatment with steroids and diuretics, CSF pressure was 85 mm H 0. In 1960, Chiodi .(5) described a patient 2 suffering with HACE who...Biol. Chem., 157, 297-302, 1945. 5. Chiodi H: "Mal de montana a forma cerebral; possible mecanismo etiopathogenico," An. Fac. Med. Lima., 43, 437

  19. Ear - blocked at high altitudes

    MedlinePlus

    ... and blocked ears; Flying and blocked ears; Eustachian tube dysfunction - high altitude ... The eustachian tube is a connection between the middle ear (the space deep to the eardrum) and the back of the ...

  20. Alaska High Altitude Photography Program

    NASA Technical Reports Server (NTRS)

    Petersen, Earl V.; Knutson, Martin A.; Ekstrand, Robert E.

    1986-01-01

    In 1978, the Alaska High Altitude Photography Program was initiated to obtain simultaneous black and white and color IR aerial photography of Alaska. Dual RC-10 and Zeiss camera systems were used for this program on NASA's U-2 and WB-57F, respectively. Data collection, handling, and distribution are discussed as well as general applications and the current status.

  1. High altitude atmospheric modeling

    NASA Technical Reports Server (NTRS)

    Hedin, Alan E.

    1988-01-01

    Five empirical models were compared with 13 data sets, including both atmospheric drag-based data and mass spectrometer data. The most recently published model, MSIS-86, was found to be the best model overall with an accuracy around 15 percent. The excellent overall agreement of the mass spectrometer-based MSIS models with the drag data, including both the older data from orbital decay and the newer accelerometer data, suggests that the absolute calibration of the (ensemble of) mass spectrometers and the assumed drag coefficient in the atomic oxygen regime are consistent to 5 percent. This study illustrates a number of reasons for the current accuracy limit such as calibration accuracy and unmodeled trends. Nevertheless, the largest variations in total density in the thermosphere are accounted for, to a very high degree, by existing models. The greatest potential for improvements is in areas where we still have insufficient data (like the lower thermosphere or exosphere), where there are disagreements in technique (such as the exosphere) which can be resolved, or wherever generally more accurate measurements become available.

  2. Stress-mediated adaptive response leading to genetic diversity and instability in metabolite contents of high medicinal value: an overview on Podophyllum hexandrum.

    PubMed

    Gupta, Manju Lata; Dutta, Ajaswrata

    2011-12-01

    Podophyllum hexandrum, known for its diversified clinical importance particularly for antineoplastic activity and valuable source for biological protection against high doses of radiation, has its unique position in the plant kingdom. Detailed understanding of mechanism and opportunity of chemical manipulations has amplified the scope of its bioactivity. Podophyllotoxin, the major active principle of this plant, has passed through various structural deviations with the basic aim of making the end product clinically more effective with minimal toxicity. However, over exploitation and limited growth has categorized this plant under endangered species. Depending upon the geographical variations, different species and subspecies of this plant have been explored. Morphological variations and quantitative differences in active principles are the major concern of its unstable medicinal value in whole and semifractionated preparations. The current review has addressed the issues related to the genetic diversity of P. hexandrum, extrinsic and intrinsic stresses responsible for its diversified nature, chemical modifications to enhance its multitasking bioactivity, and efforts for its cultivation and production of important metabolites to avoid collection of wild species due to its critically endangered nature.

  3. High Altitude Ozone Research Balloon

    NASA Technical Reports Server (NTRS)

    Cauthen, Timothy A.; Daniel, Leslie A.; Herrick, Sally C.; Rock, Stacey G.; Varias, Michael A.

    1990-01-01

    In order to create a mission model of the high altitude ozone research balloon (HAORB) several options for flight preparation, altitude control, flight termination, and payload recovery were considered. After the optimal launch date and location for two separate HAORB flights were calculated, a method for reducing the heat transfer from solar and infrared radiation was designed and analytically tested. This provided the most important advantage of the HAORB over conventional balloons, i.e., its improved flight duration. Comparisons of different parachute configurations were made, and a design best suited for the HAORB's needs was determined to provide for payload recovery after flight termination. In an effort to avoid possible payload damage, a landing system was also developed.

  4. Pulmonary Adaptation to High Altitude.

    DTIC Science & Technology

    1982-08-01

    Fluorometric assays of high energy phosphates in respiratory and limb muscles plus a variety of histochemical techniques to more fully describe the...phenomenon--in the form of the critical level of CO2 required to maintain rhythmic breathing during sleep and explains the effect of acute oxygen therapy on...AD-AR140 51.4 PULMONARY ADAPTATION TO HIGH ALTITUDE(U) WISCONSIN i/i UNIV-MADISON J R DEMPSEY AUG 82 DAMD17-77-C-786 UNCLAS51FIED F/G 619 ML

  5. [Children and pregnant women at high altitude].

    PubMed

    Rehakova, P; Rexhaj, E; Farron, F; Duplain, H

    2014-05-07

    Nowadays, high altitude resorts have become popular destinations for family vacations. Based on a limited number of publications and international guidelines, this article summarizes the effects of high altitude on children and pregnant women. Children also suffer from high altitude-related diseases, however their presentation and clinical significance are different from their adult counterparts. Careful planning of the itinerary with respect to altitude of the overnight stays, access to medical services and potential evacuation routes is the cornerstone of a successful vacation.

  6. High-altitude reconnaissance aircraft

    NASA Technical Reports Server (NTRS)

    Yazdi, Renee Anna

    1991-01-01

    At the equator the ozone layer ranges from 65,000 to 130,000+ ft, which is beyond the capabilities of the ER-2, NASA's current high-altitude reconnaissance aircraft. This project is geared to designing an aircraft that can study the ozone layer. The aircraft must be able to satisfy four mission profiles. The first is a polar mission that ranges from Chile to the South Pole and back to Chile, a total range of 6000 n.m. at 100,000 ft with a 2500-lb payload. The second mission is also a polar mission with a decreased altitude and an increased payload. For the third mission, the aircraft will take off at NASA Ames, cruise at 100,000 ft, and land in Chile. The final mission requires the aircraft to make an excursion to 120,000 ft. All four missions require that a subsonic Mach number be maintained because of constraints imposed by the air sampling equipment. Three aircraft configurations were determined to be the most suitable for meeting the requirements. The performance of each is analyzed to investigate the feasibility of the mission requirements.

  7. Fire Fighting from High Altitude

    NASA Technical Reports Server (NTRS)

    Cobleigh, Brent; Ambrosia, Vince

    2007-01-01

    A viewgraph presentation on high altitude fire fighting is shown. The topics include: 1) Yellowstone Fire - 1988; 2) 2006 Western States Fire Mission Over-View; 3) AMS-Wildfire Scanner; 4) October 24-25 Mission: Yosemite NP and NF; 5) October 24-25 Mission MODIS Overpass; 6) October 24-25 Mission Highlights; 7) October 28-29 Mission Esperanza Fire, California; 8) Response to the Esperanza Fire in Southern California -- Timeline Oct 27-29 2006; 9) October 28-29 Mission Esperanza Fire Altair Flight Routing; 10) October 28-29 Mission Esperanza Fire Altair Over-Flights; 11) October 28-29 Mission Highlights; 12) Results from the Esperanza Fire Response; 13) 2007 Western States Fire Mission; and 14) Western States UAS Fire Mission 2007

  8. Hormonal contraceptives and travel to high altitude.

    PubMed

    Keyes, Linda E

    2015-03-01

    Women frequently ask about the safety and efficacy of using hormonal contraception (HC), either oral contraceptive pills (OC) or other forms, when traveling to high altitude locales. What are the risks and benefits of using HC at high altitude? Does HC affect acclimatization, exercise performance, or occurrence of acute mountain sickness? This article reviews current data regarding the risks and benefits of HC at high altitude, both demonstrated and theoretical, with the aim of helping health care providers to advise women traveling above 2500 meters. Most healthy women can safely use HC when traveling to high altitude, but should be aware of the potential risks and inconveniences.

  9. Jupiter's High-Altitude Clouds

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The New Horizons Multispectral Visible Imaging Camera (MVIC) snapped this incredibly detailed picture of Jupiter's high-altitude clouds starting at 06:00 Universal Time on February 28, 2007, when the spacecraft was only 2.3 million kilometers (1.4 million miles) from the solar system's largest planet. Features as small as 50 kilometers (30 miles) are visible. The image was taken through a narrow filter centered on a methane absorption band near 890 nanometers, a considerably redder wavelength than what the eye can see. Images taken through this filter preferentially pick out clouds that are relatively high in the sky of this gas giant planet because sunlight at the wavelengths transmitted by the filter is completely absorbed by the methane gas that permeates Jupiter's atmosphere before it can reach the lower clouds.

    The image reveals a range of diverse features. The south pole is capped with a haze of small particles probably created by the precipitation of charged particles into the polar regions during auroral activity. Just north of the cap is a well-formed anticyclonic vortex with rising white thunderheads at its core. Slightly north of the vortex are the tendrils of some rather disorganized storms and more pinpoint-like thunderheads. The dark 'measles' that appear a bit farther north are actually cloud-free regions where light is completely absorbed by the methane gas and essentially disappears from view. The wind action considerably picks up in the equatorial regions where giant plumes are stretched into a long wave pattern. Proceeding north of the equator, cirrus-like clouds are shredded by winds reaching speeds of up to 400 miles per hour, and more pinpoint-like thunderheads are visible. Although some of the famous belt and zone structure of Jupiter's atmosphere is washed out when viewed at this wavelength, the relatively thin North Temperate Belt shows up quite nicely, as does a series of waves just north of the belt. The north polar region of

  10. High Altitude Illnesses in Hawai‘i

    PubMed Central

    2014-01-01

    High Altitude Headache (HAH), Acute Mountain Sickness (AMS), and High Altitude Cerebral Edema (HACE) are all high altitude related illnesses in order of severity from the mildly symptomatic to the potentially life-threatening. High altitude illnesses occur when travelers ascend to high altitudes too rapidly, which does not allow enough time for the body to adjust. Slow graded ascent to the desired altitude and termination of ascent if AMS symptoms present are keys to illness prevention. Early recognition and rapid intervention of AMS can halt progression to HACE. Pharmacologic prophylaxis with acetazolamide is a proven method of prevention and treatment of high altitude illness. If prevention fails then treatment modalities include supplemental oxygen, supportive therapy, hyperbaric treatment, and dexamethasone. Given the multitude of visitors to the mountains of Hawai‘i, high altitude illness will continue to persist as a prevalent local condition. This paper will emphasize the prevention and early diagnosis of AMS so that the illness does not progress to HACE. PMID:25478293

  11. High-Altitude Hydration System

    NASA Technical Reports Server (NTRS)

    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.

  12. Developmental functional adaptation to high altitude: review.

    PubMed

    Frisancho, A Roberto

    2013-01-01

    Various approaches have been used to understand the origins of the functional traits that characterize the Andean high-altitude native. Based on the conceptual framework of developmental functional adaptation which postulates that environmental influences during the period of growth and development have long lasting effects that may be expressed during adulthood, we initiated a series of studies addressed at determining the pattern of physical growth and the contribution of growth and development to the attainment of full functional adaptation to high-altitude of low and high altitude natives living under rural and urban conditions. Current research indicate that: (a) the pattern of growth at high altitude due to limited nutritional resources, physical growth in body size is delayed but growth in lung volumes is accelerated because of hypoxic stress); (b) low-altitude male and female urban natives can attain a full functional adaptation to high altitude by exposure to high-altitude hypoxia during the period of growth and development; (c) both experimental studies on animals and comparative human studies indicate that exposure to high altitude during the period of growth and development results in the attainment of a large residual lung volume; (d) this developmentally acquired enlarged residual lung volume and its associated increase in alveolar area when combined with the increased tissue capillarization and moderate increase in red blood cells and hemoglobin concentration contributes to the successful functional adaptation of the Andean high-altitude native to hypoxia; and (e) any specific genetic traits that are related to the successful functional adaptation of Andean high-altitude natives have yet to be identified.

  13. Sleep at high altitude: guesses and facts.

    PubMed

    Bloch, Konrad E; Buenzli, Jana C; Latshang, Tsogyal D; Ulrich, Silvia

    2015-12-15

    Lowlanders commonly report a poor sleep quality during the first few nights after arriving at high altitude. Polysomnographic studies reveal that reductions in slow wave sleep are the most consistent altitude-induced changes in sleep structure identified by visual scoring. Quantitative spectral analyses of the sleep electroencephalogram have confirmed an altitude-related reduction in the low-frequency power (0.8-4.6 Hz). Although some studies suggest an increase in arousals from sleep at high altitude, this is not a consistent finding. Whether sleep instability at high altitude is triggered by periodic breathing or vice versa is still uncertain. Overnight changes in slow wave-derived encephalographic measures of neuronal synchronization in healthy subjects were less pronounced at moderately high (2,590 m) compared with low altitude (490 m), and this was associated with a decline in sleep-related memory consolidation. Correspondingly, exacerbation of breathing and sleep disturbances experienced by lowlanders with obstructive sleep apnea during a stay at 2,590 m was associated with poor performance in driving simulator tests. These findings suggest that altitude-related alterations in sleep may adversely affect daytime performance. Despite recent advances in our understanding of sleep at altitude, further research is required to better establish the role of gender and age in alterations of sleep at different altitudes, to determine the influence of acclimatization and of altitude-related illness, and to uncover the characteristics of sleep in highlanders that may serve as a study paradigm of sleep in patients exposed to chronic hypoxia due to cardiorespiratory disease.

  14. Postnatal cardiopulmonary adaptations to high altitude.

    PubMed

    Huicho, Luis

    2007-09-30

    Postnatal cardiopulmonary adaptations to high altitude constitute a key component of any set of responses developed to face high altitude hypoxia. Such responses are required ultimately to meet the energy demands necessary for adequate functioning at cell and organism level. After a brief insight on general and cardiopulmonary comparative studies in growing and adult organisms, differences and possible explanations for varying cardiopulmonary pathology, pulmonary artery hypertension, persistent right ventricular predominance and subacute high altitude pulmonary hypertension in different populations of children living at high altitude are discussed. Potential long-term implications of early chronic hypoxic exposure on later diseases are also presented. It is hoped that this review will help the practicing physician working at high altitude to make informed decisions concerning individual pediatric patients, specifically with regard to diagnosis and management of altitude-related cardiopulmonary pathology. Finally, plausibility and the knowledge-base of public health interventions to reduce the risks posed by suboptimal or inadequate postnatal cardiopulmonary responses to high altitude are discussed.

  15. Carbon monoxide studies at high altitude.

    PubMed

    McGrath, J J

    1988-01-01

    In high altitude areas, ambient carbon monoxide (CO) concentrations are rising because of the increasing number of new residents and tourists, and their concomitant use of motor vehicles and heating appliances. There are, however, comparatively few studies of the acute or chronic physiological effects that may be caused by inhaling CO at high altitude. There are data supporting the concept that the effects of breathing CO at high altitude are additive, and data suggesting that the effects may be more than additive. Visual sensitivity and flicker fusion frequency are reduced in humans inhaling CO at high altitude. One provocative study suggests that the increase in coronary capillarity seen with chronic altitude exposure may be blocked by CO. We exposed male, laboratory rats for 6 weeks to 100 ppm CO, 4676 m (15,000 ft) simulated high altitude (SHA), and CO at SHA. SHA increase hematocrit ratio (Hct) and right ventricle weight, but decreased body weight. CO increased Hct and left ventricle weight. Our results indicate that 100 ppm CO does not exacerbate the effects produced by exposure to 4676 m altitude.

  16. The Impact of Moderate-Altitude Staging on Pulmonary Arterial Hemodynamics after Ascent to High Altitude

    DTIC Science & Technology

    2010-01-01

    et al., 1956; Sime et al., 1974). The magnitude of the PAP in- crease plays an important role in the development of high altitude pulmonary edema ...implications for travelers to high altitude. High altitude pulmonary edema (HAPE) is an important cause of high altitude morbidity and mortality, and...P., and Oelz O. (1991). Prevention of high-altitude pulmonary edema by nifedipine. N. Engl. J. Med. 325:1284–1289. Beidleman B.A., Fulco C.S., Muza

  17. High Altitude Launch for a Practical SSTO

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Denis, Vincent

    2003-01-01

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

  18. High Altitude Launch for a Practical SSTO

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Denis, Vincent

    2003-01-01

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

  19. High-altitude cerebral oedema mimicking stroke

    PubMed Central

    Yanamandra, Uday; Gupta, Amul; Patyal, Sagarika; Varma, Prem Prakash

    2014-01-01

    High-altitude cerebral oedema (HACO) is the most fatal high-altitude illness seen by rural physicians practising in high-altitude areas. HACO presents clinically with cerebellar ataxia, features of raised intracranial pressure (ICP) and coma. Early identification is important as delay in diagnosis can be fatal. We present two cases of HACO presenting with focal deficits mimicking stroke. The first patient presented with left-sided hemiplegia associated with the rapid deterioration in the sensorium. Neuroimaging revealed features suggestive of vasogenic oedema. The second patient presented with monoplegia of the lower limb. Neuroimaging revealed perfusion deficit in anterior cerebral artery territory. Both patients were managed with dexamethasone and they improved dramatically. Clinical picture and neuroimaging closely resembled acute ischaemic stroke in both cases. Thrombolysis in these patients would have been disastrous. Recent travel to high altitude, young age, absence of atherosclerotic risk factors and features of raised ICP concomitantly directed the diagnosis to HACO. PMID:24671373

  20. High altitude medicine for family physicians.

    PubMed Central

    McMurray, S. J.

    1994-01-01

    High altitude medicine deals with a continuum of diseases ranging from a mild discomfort to serious ailments affecting all organ systems, including the lungs, brain, and eyes. Decreased oxygen tension is the primary cause. The main principles of prevention are staging and graded ascent to allow acclimatization. Adventure travel to high altitude destinations is becoming increasingly popular; family physicians should be informed of the medical problems associated with such travel. Images p712-a p715-a p716-a PMID:8199523

  1. Early history of high-altitude physiology.

    PubMed

    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.

  2. Paschen Considerations for High Altitude Airships

    NASA Technical Reports Server (NTRS)

    Ferguson, D. C.; Hillard, G. B.

    2004-01-01

    Recently, there have been several proposals submitted to funding agencies for long-lived high altitude (about 70,000 feet) airships for communications, surveillance, etc. In order for these airships to remain at altitude, high power, high efficiency, lightweight solar arrays must be used, and high efficiency power management and distribution systems must be employed. The needs for high power and high efficiency imply high voltage systems. However, the air pressure at these extreme altitudes is such that electrical power systems will be near the Paschen discharge minimum over a wide range of electrode separations. In this paper, preliminary calculations are made for acceptable high voltage design practices under ambient, hydrogen and helium gas atmospheres.

  3. [Effects of high altitude on bronchial asthma].

    PubMed

    Schultze-Werninghaus, G

    2008-03-01

    Sojourns in the high mountains have been recommended to patients with asthma for many decades. It is the aim of this contribution to summarise the published studies about the effects of a stay at > 1500 m above sea level on asthmatic patients. These data from 428 adolescent and adult patients indicate an improvement of asthma symptoms and lung function during sojourns at high altitude. In many patients a reduction of the steroid therapy was achievable. Profound changes in the immune system have been demonstrated at high altitude, with a reduction of B- and T-helper cell activation. Total and mite-specific immunoglobulin E antibodies decrease significantly during longer sojourns. These changes are associated with a reduction of airway inflammation (e. g., reduction of eosinophil activation, NO exhalation and bronchial hyper-responsiveness). The fact that also patients with non-allergic asthma demonstrate a reduction of their airway inflammation at high altitude suggests that the high altitude climate has beneficial effects on asthma beyond the effects of allergen avoidance. High UV exposure and low humidity could be important additional factors, to explain the reductions in asthma severity in the high mountain climate. Larger controlled studies should be performed to prove the positive effects of the high altitude climate on asthma.

  4. High altitude pulmonary edema in mountain climbers.

    PubMed

    Korzeniewski, Krzysztof; Nitsch-Osuch, Aneta; Guzek, Aneta; Juszczak, Dariusz

    2015-04-01

    Every year thousands of ski, trekking or climbing fans travel to the mountains where they stay at the altitude of more than 2500-3000m above sea level or climb mountain peaks, often exceeding 7000-8000m. High mountain climbers are at a serious risk from the effects of adverse environmental conditions prevailing at higher elevations. They may experience health problems resulting from hypotension, hypoxia or exposure to low temperatures; the severity of those conditions is largely dependent on elevation, time of exposure as well as the rate of ascent and descent. A disease which poses a direct threat to the lives of mountain climbers is high altitude pulmonary edema (HAPE). It is a non-cardiogenic pulmonary edema which typically occurs in rapidly climbing unacclimatized lowlanders usually within 2-4 days of ascent above 2500-3000m. It is the most common cause of death resulting from the exposure to high altitude. The risk of HAPE rises with increased altitude and faster ascent. HAPE incidence ranges from an estimated 0.01% to 15.5%. Climbers with a previous history of HAPE, who ascent rapidly above 4500m have a 60% chance of illness recurrence. The aim of this article was to present the relevant details concerning epidemiology, pathophysiology, clinical symptoms, prevention, and treatment of high altitude pulmonary edema among climbers in the mountain environment.

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

    PubMed

    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.

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

    PubMed Central

    Lohani, Benu; Murphy, Holly

    2016-01-01

    Abstract 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. PMID:27768392

  7. Sonic Thermometer for High-Altitude Balloons

    NASA Technical Reports Server (NTRS)

    Bognar, John

    2012-01-01

    The sonic thermometer is a specialized application of well-known sonic anemometer technology. Adaptations have been made to the circuit, including the addition of supporting sensors, which enable its use in the high-altitude environment and in non-air gas mixtures. There is a need to measure gas temperatures inside and outside of superpressure balloons that are flown at high altitudes. These measurements will allow the performance of the balloon to be modeled more accurately, leading to better flight performance. Small thermistors (solid-state temperature sensors) have been used for this general purpose, and for temperature measurements on radiosondes. A disadvantage to thermistors and other physical (as distinct from sonic) temperature sensors is that they are subject to solar heating errors when they are exposed to the Sun, and this leads to issues with their use in a very high-altitude environment

  8. Wind study for high altitude platform design

    NASA Technical Reports Server (NTRS)

    Strganac, T. W.

    1979-01-01

    An analysis of upper air winds was performed to define the wind environment at potential operating altitudes for high altitude powered platform concepts. Wind conditions of the continental United States, Pacific area (Alaska to Sea of Japan), and European area (Norwegian and Mediterranean Sea) were obtained using a representative network of sites selected based upon adequate high altitude sampling, geographic dispersion, and observed upper wind patterns. A data base of twenty plus years of rawinsonde gathered wind information was used in the analysis. Annual variations from surface to 10 mb pressure altitude were investigated to encompass the practical operating range for the platform concepts. Parametric analysis for the United States and foreign areas was performed to provide a basis for vehicle system design tradeoffs. This analysis of wind magnitudes indicates the feasibility of annual operation at a majority of sites and more selective seasonal operation for the extreme conditions between the pressure altitudes of 100 to 25 mb based upon the assumed design speeds.

  9. Tests of artificial flight at high altitudes

    NASA Technical Reports Server (NTRS)

    Gradenwitz, Arthur

    1920-01-01

    If we wish to form an accurate idea of the extraordinary progress achieved in aeronautics, a comparison must be made of the latest altitude records and the figures regarded as highest attainable limit some ten years ago. It is desirable, for two reasons, that we should be able to define the limit of the altitudes that can be reached without artificial aid. First, to know to what extent the human body can endure the inhalation of rarified air. Second, the mental capacity of the aviator must be tested at high altitudes and the limit known below which he is able to make reliable observations without being artificially supplied with oxygen. A pneumatic chamber was used for the most accurate observations.

  10. The morbid anatomy of high altitude

    PubMed Central

    Heath, Donald

    1979-01-01

    The morbid anatomical changes which take place in man and animals exposed to the chronic hypoxia of residence at high altitude are briefly reviewed. ImagesFig. 1Fig. 2Fig. 3Fig. 5Fig. 4Fig. 6Fig. 7Fig. 8 PMID:493205

  11. High-altitude physiology: lessons from Tibet

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

    Polycythemia is a universal lowlander response to altitude; healthy Andean high-altitude natives also have elevated [Hb]. While this may enhance O2 transport to tissues, studies have shown that acute isovolumic changes in [Hb] do not affect exercise capacity. Many high-altitude Tibetans have evolved sea-level values of [Hb], providing a natural opportunity to study this issue. In 21 young healthy male Tibetans with [Hb] between 15 and 23 g/dl, we measured VO2MAX and O2 transport capacity at 4200m. VO2MAX was higher when [Hb] was lower (P<0.05), enabled by both higher cardiac output and muscle O2 diffusional conductance, but neither ventilation nor the alveolar-arterial PO2 difference (AaPO2) varied with [Hb]. In contrast, Andean high altitude natives remain polycythemic with larger lungs and higher lung diffusing capacity, a smaller exercising AaPO2, and lower ventilation. The challenges now are (1) to understand the different adaptive pathways used by Andeans and Tibetans, and (2) to determine in Tibetans whether, during evolution, reduced [Hb] appeared first, causing compensatory cardiac and muscle adaptations, or if enhanced cardiac function and muscle O2 transport capacity appeared first, permitting secondary reduction in [Hb]. For (2), further research is necessary to determine the basis of enhanced cardiac function and muscle O2 transport, and identify molecular targets of evolution in heart and muscle. Putative mutations can then be timed and compared to appearance of those affecting [Hb].

  12. Breathing and sleep at high altitude.

    PubMed

    Ainslie, Philip N; Lucas, Samuel J E; Burgess, Keith R

    2013-09-15

    We provide an updated review on the current understanding of breathing and sleep at high altitude in humans. We conclude that: (1) progressive changes in pH initiated by the respiratory alkalosis do not underlie early (<48 h) ventilatory acclimatization to hypoxia (VAH) because this still proceeds in the absence of such alkalosis; (2) for VAH of longer duration (>48 h), complex cellular and neurochemical re-organization occurs both in the peripheral chemoreceptors as well as within the central nervous system. The latter is likely influenced by central acid-base changes secondary to the extent of the initial respiratory responses to initial exposure to high altitude; (3) sleep at high altitude is disturbed by various factors, but principally by periodic breathing; (4) the extent of periodic breathing during sleep at altitude intensifies with duration and severity of exposure; (5) complex interactions between hypoxic-induced enhancement in peripheral and central chemoreflexes and cerebral blood flow--leading to higher loop gain and breathing instability--underpin this development of periodic breathing during sleep; (6) because periodic breathing may elevate rather than reduce mean SaO2 during sleep, this may represent an adaptive rather than maladaptive response; (7) although oral acetazolamide is an effective means to reduce periodic breathing by 50-80%, recent studies using positive airway pressure devices to increase dead space, hyponotics and theophylline are emerging but appear less practical and effective compared to acetazolamide. Finally, we suggest avenues for future research, and discuss implications for understanding sleep pathology.

  13. Estimation of high altitude Martian dust parameters

    NASA Astrophysics Data System (ADS)

    Pabari, Jayesh; Bhalodi, Pinali

    2016-07-01

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

  14. High Altitude Plasma Instrument (HAPI) data analysis

    NASA Technical Reports Server (NTRS)

    Burch, J. L.

    1994-01-01

    The objectives of the Dynamics Explorer mission are to investigate the coupling of energy, mass, and momentum among the earth's magnetosphere, ionosphere, and upper atmosphere. At launch, on August 3, 1981, DE-1 was placed into an elliptical polar orbit having an apogee of 23,130 km to allow global auroral imaging and crossings of auroral field lines at altitudes of several thousand kilometers. At the same time DE-2 was placed into a polar orbit, coplanar with that of DE-1 but with a perigee altitude low enough (309 km) for neutral measurements and an apogee altitude of 1012 km. The DE-1 High Altitude Plasma Instrument (HAPI) provided data on low and medium energy electrons and ions from August 13, 1981 until December 1, 1981, when a high-voltage failure occured. Analysis of HAPI data for the time period of this contract has produced new results on the source mechanisms for electron conical distributions, particle acceleration phenomena in auroral acceleration regions, Birkeland currents throughout the nightside auroral regions, the source region for auroral kilometric radiation (AKR), and plasma injection phenomena in the polar cusp.

  15. [High altitude anemia: validity of definition criteria].

    PubMed

    Yepez, R; Estevez, E; Galan, P; Chauliac, M; Davila, M; Calle, A; Estrella, R; Masse-Raimbault, A M; Hercberg, S

    1994-01-01

    The effect of iron and folate supplementation on the hemoglobin response and iron status was studied in male and female equatorian medical students: 66 in Quito (2,800 m altitude) and 40 in Guayaquil (sea level). At the end of the supplementation, there was a nearly complete disappearance of biochemical evidence of iron deficiency in the two groups of students. In Quito, 30% of the men and 26% of the women increased their hemoglobin concentration by more than 1 g/dl after one month of supplementation and could be considered as true anemics, compared to 31% of the men and 29% of the women in Guayaquil. This study shows that at sea level, cut-off points defined by WHO for hemoglobin, taking as reference the impact of a supplementation trial, have a specificity of 100% but poor sensitivity (58%). For people living at high altitudes, cut-off limits adjusted for altitude seem unsuitable: the specificity is 98% but the sensitivity is 0%. Studies taking into account all the factors impacting on the hemoglobin level could be useful for defining cut-off points for high-altitude anemia better than those currently recommended.

  16. HAWC - The High Altitude Water Cherenkov Detector

    NASA Astrophysics Data System (ADS)

    Tepe, Andreas; HAWC Collaboration

    2012-07-01

    The high altitude water Cherenkov observatory (HAWC) is an instrument for the detection of high energy cosmic gamma-rays. Its predecessor Milagro has successfully proven that the water Cherenkov technology for gamma-ray astronomy is a useful technique. HAWC is currently under construction at Sierra Negra in Mexico at an altitude of 4100 m and will include several improvements compared to Milagro. Two complementary DAQ systems of the HAWC detector allow for the observation of a large fraction of the sky with a very high duty cycle and independent of environmental conditions. HAWC will observe the gamma-ray sky from about 100 GeV up to 100 TeV. Also the cosmic ray flux anisotropy on different angular length scales is object of HAWC science. Because of HAWC's large effective area and field of view, we describe its prospects to observe gamma-ray bursts (GRBs) as an example for transient sources.

  17. High altitude syndromes at intermediate altitudes: a pilot study in the Australian Alps.

    PubMed

    Slaney, Graham; Cook, Angus; Weinstein, Philip

    2013-10-01

    Our hypothesis is that symptoms of high altitude syndromes are detectable even at intermediate altitudes, as commonly encountered under Australian conditions (<2500 m above sea level). High altitude medicine has long recognised several syndromes associated with rapid ascent to altitudes above 2500 m, including high altitude pulmonary oedema (HAPE), high altitude cerebral oedema (HACE) and high altitude flatus expulsion (HAFE). Symptoms of high altitude syndromes are of growing concern because of the global trend toward increasing numbers of tourists and workers exposed to both rapid ascent and sustained physical activity at high altitude. However, in Australia, high altitude medicine has almost no profile because of our relatively low altitudes by international standards. Three factors lead us to believe that altitude sickness in Australia deserves more serious consideration: Australia is subject to rapid growth in alpine recreational industries; altitude sickness is highly variable between individuals, and some people do experience symptoms already at 1500 m; and there is potential for an occupational health and safety issue amongst workers. To test this hypothesis we examined the relationship between any high altitude symptoms and a rapid ascent to an intermediate altitude (1800 m) by undertaking an intervention study in a cohort of eight medical clinic staff, conducted during July of the 2012 (Southern Hemisphere) ski season, using self-reporting questionnaires, at Mansfield (316 m above sea level) and at the Ski Resort of Mt Buller (1800 m), Victoria, Australia. The intervention consisted of ascent by car from Mansfield to Mt Buller (approx. 40 min drive). Participants completed a self-reporting questionnaire including demographic data and information on frequency of normal homeostatic processes (fluid intake and output, food intake and output, symptoms including thirst and headaches, and frequency of passing wind or urine). Data were recorded in hourly periods

  18. Is high altitude pulmonary edema relevant to Hawai'i?

    PubMed

    Cornell, Seth Lewis

    2014-11-01

    High altitude clinical syndromes have been described in the medical literature but may be under recognized in the state of Hawai'i. As tourism increases, high altitude injuries may follow given the easy access to high altitude attractions. Visitors and clinicians should be aware of the dangers associated with the rapid ascent to high altitudes in the perceived comfort of a vehicle. This paper will review the basic pathophysiology, prevention, and treatment of the most serious of the high altitude clinical syndromes, high altitude pulmonary edema.

  19. Is High Altitude Pulmonary Edema Relevant to Hawai‘i?

    PubMed Central

    2014-01-01

    High altitude clinical syndromes have been described in the medical literature but may be under recognized in the state of Hawai‘i. As tourism increases, high altitude injuries may follow given the easy access to high altitude attractions. Visitors and clinicians should be aware of the dangers associated with the rapid ascent to high altitudes in the perceived comfort of a vehicle. This paper will review the basic pathophysiology, prevention, and treatment of the most serious of the high altitude clinical syndromes, high altitude pulmonary edema. PMID:25478294

  20. High Altitude Cooking and Food Safety

    MedlinePlus

    ... Administrative Forms Standard Forms Skip Navigation Z7_0Q0619C0JGR010IFST1G5B10H1 Web Content Viewer (JSR 286) Actions ${title} Loading... / Topics / ... High Altitude Cooking and Food Safety Z7_0Q0619C0JGR010IFST1G5B10H3 Web Content Viewer (JSR 286) Actions ${title} Loading... Z7_ ...

  1. Mini review of high altitude health problems in Ladakh.

    PubMed

    Norboo, T; Saiyed, H N; Angchuk, P T; Tsering, P; Angchuk, S T; Phuntsog, S T; Yahya, M; Wood, Steve; Bruce, N G; Ball, K P

    2004-05-01

    Ladakh is a sparsely populated area of Indian Himalaya lying at 3-4500 m altitude mainly consisting of arid desert. This paper will discuss high altitude health problems in Ladakh under the following headings. 1. Acute altitude illness: acute mountain sickness (AMS), high altitude pulmonary edema (HAPE) and high altitude cerebral edema (HACE). 2. Effects of prolonged and permanent exposure to high altitude: (subacute and chronic mountain sickness). 3. Environmental dust and domestic fire pollution resulting in non-occupational pneumoconiosis and high prevalence of respiratory morbidity.

  2. The High Altitude Water Cherenkov Observatory

    NASA Astrophysics Data System (ADS)

    Mostafa, Miguel; HAWC Collaboration

    2016-03-01

    The High Altitude Water Cherenkov (HAWC) Observatory is a continuously operated, wide field of view experiment comprised of an array of 300 water Cherenkov detectors (WCDs) to study transient and steady emission of TeV gamma and cosmic rays. Each 200000 l WCD is instrumented with 4 PMTs providing charge and timing information. The array covers ~22000 m2 at an altitude of 4100 m a.s.l. inside the Pico de Orizaba national park in Mexico. The high altitude, large active area, and optical isolation of the PMTs allows us to reliably estimate the energy and determine the arrival direction of gamma and cosmic rays with significant sensitivity over energies from several hundred GeV to a hundred TeV. Continuously observing 2 / 3 of the sky every 24 h, HAWC plays a significant role as a survey instrument for multi-wavelength studies. The performance of HAWC makes possible the detection of both transient and steady emissions, the study of diffuse emission and the measurement of the spectra of gamma-ray sources at TeV energies. HAWC is also sensitive to the emission from GRBs above 100 GeV. I will highlight the results from the first year of operation of the full HAWC array, and describe the ongoing site work to expand the array by a factor of 4 to explore the high energy range.

  3. High altitude plumes at Mars morning terminator

    NASA Astrophysics Data System (ADS)

    Sanchez-Lavega, A.; Garcia Muñoz, A.; Garcia Melendo, E.; Perez-Hoyos, S.; Gomez Forrellad, J. M.; Pellier, C.; Delcroix, M.; Lopez Valverde, M. A.; González Galindo, F.; Jaeschke, W.; Parker, D.; Phillips, J.; Peach, D.

    2015-10-01

    In March and April 2012 two extremely high altitude plumes were observed at the Martian terminator reaching 200 -250 km or more above the surface[1]. They were located at about 195o West longitude and 45o South latitude (at Terra Cimmeria) and extended ˜500 -1,000 km in both North-South and East- West, and lasted for about 10 days. Both plumes exhibited day-to-day variability, and were seen at the morning terminator but not at the evening limb. Another large plume was captured on Hubble Space Telescope images in May 1997 at 99º West longitude and 3º South latitude, but its altitude cannot be pr ecisely determined.Broad-band photometry was performed of both events in the spectral range 255 nm -1052 nm. Based on the observed properties, we discuss different possible scenarios for the mechanism responsible for the formation of these plumes.

  4. The High Altitude Gamma Ray Observatory, HAWC

    NASA Astrophysics Data System (ADS)

    González, M. M.

    2011-10-01

    The Volcano Sierra Negra in Puebla, Mexico was selected to host HAWC (High Altitude Water Cherenkov), a unique obervatory of wide field of view (2π sr) capable of observing the sky continously at energies from 0.5 TeV to 100 TeV. HAWC is an array of 300 large water tanks (7.3 m diameter × 5 m depth) at an altitude of 4100 m. a. s. l. Each tank is instrumented with three upward-looking photomultipliers tubes. The full array will be capable of observing the most energetic gamma rays from the most violent events in the universe. HAWC will be 15 times more sensitive than its predecesor, Milagro. We present HAWC, the scientific case and capabilities.

  5. Development of a high altitude Spin Parachute

    NASA Technical Reports Server (NTRS)

    Silbert, M. N.

    1981-01-01

    A specially configured 16.6 foot (5.1 meter) Disc Gap Band (DGB) Spin Parachute has been designed, developed, integrated with a sounding rocket, and qualified by flight testing. Design requirements include (1) stable parachute should successfully deploy in the altitude region of 260,000 feet (80 kilometers) from a Super Arcas launch vehicle; (2) after deployment, parachute and payload spin rate should be greater than three rpm; (3) four electric field sensors should be mounted on parachute shroud lines and have provisions to be electrically connected to the suspended payload; and (4) time above 100,000 feet (30 kilometers) should exceed five minutes. The successful meeting of these requirements provided the first known high-altitude deployment of a Spin Parachute.

  6. Design and Development of a High Altitude Protective Assembly.

    DTIC Science & Technology

    CWU-3/P ANTIGRAVITY SUITS, CWU-12/P ANTIEXPOSURE SUITS, HAPA(HIGH ALTITUDE PROTECTIVE ASSEMBLIES), *HIGH ALTITUDE PROTECTIVE ASSEMBLIES, LPU-3/P LIFE PRESERVERS, MA-3 VENTILATION GARMENTS, PARACHUTE HARNESSES, PARTIAL PRESSURE SUITS.

  7. Acute high-altitude illness: a clinically orientated review

    PubMed Central

    Smedley, Tom

    2013-01-01

    Acute high-altitude illness is an encompassing term for the range of pathology that the unacclimatised individual can develop at increased altitude. This includes acute mountain sickness, high-altitude cerebral oedema and high-altitude pulmonary oedema. These conditions represent an increasing clinical problem as more individuals are exposed to the hypobaric hypoxic environment of high altitude for both work and leisure. In this review of acute high-altitude illness, the epidemiology, risk factors and pathophysiology are explored, before their prevention and treatment are discussed. Appropriate ascent rate remains the most effective acute high-altitude illness prevention, with pharmacological prophylaxis indicated in selected individuals. Descent is the definitive treatment for acute high-altitude illness, with the adjuncts of oxygen and specific drug therapies. PMID:26516505

  8. High altitude balloon experiments at IIA

    NASA Astrophysics Data System (ADS)

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

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

  9. High-altitude adaptations in vertebrate hemoglobins.

    PubMed

    Weber, Roy E

    2007-09-30

    Vertebrates at high altitude are subjected to hypoxic conditions that challenge aerobic metabolism. O(2) transport from the respiratory surfaces to tissues requires matching between the O(2) loading and unloading tensions and the O(2)-affinity of blood, which is an integrated function of hemoglobin's intrinsic O(2)-affinity and its allosteric interaction with cellular effectors (organic phosphates, protons and chloride). Whereas short-term altitudinal adaptations predominantly involve adjustments in allosteric interactions, long-term, genetically-coded adaptations typically involve changes in the structure of the haemoglobin molecules. The latter commonly comprise substitutions of amino acid residues at the effector binding sites, the heme-protein contacts, or at intersubunit contacts that stabilize either the low-affinity ('Tense') or the high-affinity ('Relaxed') structures of the molecules. Molecular heterogeneity (multiple isoHbs with differentiated oxygenation properties) can further broaden the range of physico-chemical conditions where Hb functions under altitudinal hypoxia. This treatise reviews the molecular and cellular mechanisms that adapt haemoglobin-oxygen affinities in mammals, birds and ectothermic vertebrates at high altitude.

  10. Growth of Han migrants at high altitude in central Asia.

    PubMed

    Weitz, Charles A; Garruto, Ralph M

    2004-01-01

    Han Chinese of low-altitude descent have been living in Qinghai Province of Western China for at least two millennia. For most of this time they have lived at elevations under 2,500 m. However, during the last four decades an increasing number of Han have moved into high-altitude towns at elevations over 3,000 m, and some above 4,000 m. There are now sufficient numbers of Han descendants who have been born and raised at high altitude to allow a comparison of their morphological and physiological growth patterns with low-altitude Han to detect the effect of hypoxia. The field study reported here was conducted by collaborating Chinese and American researchers over a 6-year period, and included 1,227 Han living at high altitude in Qinghai and at low altitude near Beijing. This study demonstrates that Han born and raised at high altitude are smaller and lighter than those at low altitude-particularly as children and adolescents. Slower growth at high altitude may be a consequence of hypoxia, but it also corresponds to poorer economic conditions in rural Qinghai Province, and thus may reflect nutritional inadequacies. Differences in altitude and/or nutrition do not seem to affect thorax dimensions, since, relative to stature, chest dimensions are similar at both high and low altitudes. Nevertheless, lung volumes are higher among Han at high altitude, possibly reflecting the influence of hypoxia on alveolar growth. The hematological values of Han growing up at 3,200 m are not different from those at low altitude-an unusual finding relative to other low-altitude groups that may reflect population differences in response to hypoxia. At 3,800 m and 4,300 m, however, Han show elevated hemoglobin relative to Han at low altitude.

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

    NASA Astrophysics Data System (ADS)

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

    1985-06-01

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

  12. High-altitude illnesses: physiology, risk factors, prevention, and treatment.

    PubMed

    Taylor, Andrew T

    2011-01-01

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

  13. Power Budget Analysis for High Altitude Airships

    NASA Technical Reports Server (NTRS)

    Choi, Sang H.; Elliott, James R.; King, Glen C.

    2006-01-01

    The High Altitude Airship (HAA) has various potential applications and mission scenarios that require onboard energy harvesting and power distribution systems. The energy source considered for the HAA s power budget is solar photon energy that allows the use of either photovoltaic (PV) cells or advanced thermoelectric (ATE) converters. Both PV cells and an ATE system utilizing high performance thermoelectric materials were briefly compared to identify the advantages of ATE for HAA applications in this study. The ATE can generate a higher quantity of harvested energy than PV cells by utilizing the cascaded efficiency of a three-staged ATE in a tandem mode configuration. Assuming that each stage of ATE material has the figure of merit of 5, the cascaded efficiency of a three-staged ATE system approaches the overall conversion efficiency greater than 60%. Based on this estimated efficiency, the configuration of a HAA and the power utility modules are defined.

  14. HAWC: The high altitude water Cherenkov observatory

    NASA Astrophysics Data System (ADS)

    Goodman, Jordan A.

    2013-02-01

    The High Altitude Water Cherenkov Observatory (HAWC) is currently being deployed at 4100m above sea level on the Vulcan Sierra Negra near Puebla, Mexico. The HAWC observatory will consist of 250-300 Water Cherenkov Detectors totaling approximately 22,000 m2 of instrumented area. The water Cherenkov technique allows HAWC to have a nearly 100% duty cycle and large field of view, making the HAWC observatory an ideal instrument for the study of transient phenomena. With its large effective area, excellent angular and energy resolutions, and efficient gamma-hadron separation, HAWC will survey the TeV gamma-ray sky, measure spectra of galactic sources from 1 TeV to beyond 100 TeV, and map galactic diffuse gamma ray emission. The science goals, instrument performance and status of the HAWC observatory will be presented.

  15. High Altitude Supersonic Decelerator Test Vehicle

    NASA Technical Reports Server (NTRS)

    Cook, Brant T.; Blando, Guillermo; Kennett, Andrew; Von Der Heydt, Max; Wolff, John Luke; Yerdon, Mark

    2013-01-01

    The Low Density Supersonic Decelerator (LDSD) project is tasked by NASA's Office of the Chief Technologist (OCT) to advance the state of the art in Mars entry and descent technology in order to allow for larger payloads to be delivered to Mars at higher altitudes with better accuracy. The project will develop a 33.5 m Do Supersonic Ringsail (SSRS) parachute, 6m attached torus, robotic class Supersonic Inflatable Aerodynamic Decelerator (SIAD-R), and an 8 m attached isotensoid, exploration class Supersonic Inflatable Aerodynamic Decelerator (SIAD-E). The SSRS and SIAD-R should be brought to TRL-6, while the SIAD-E should be brought to TRL-5. As part of the qualification and development program, LDSD must perform a Mach-scaled Supersonic Flight Dynamics Test (SFDT) in order to demonstrate successful free flight dynamic deployments at Mars equivalent altitude, of all three technologies. In order to perform these tests, LDSD must design and build a test vehicle to deliver all technologies to approximately 180,000 ft and Mach 4, deploy a SIAD, free fly to approximately Mach 2, deploy the SSRS, record high-speed and high-resolution imagery of both deployments, as well as record data from an instrumentation suite capable of characterizing the technology induced vehicle dynamics. The vehicle must also be recoverable after splashdown into the ocean under a nominal flight, while guaranteeing forensic data protection in an off nominal catastrophic failure of a test article that could result in a terminal velocity, tumbling water impact.

  16. High-altitude illness induced by tooth root infection

    PubMed Central

    Finsterer, J

    1999-01-01

    High-altitude illness may occur after recent pulmonary infection, but high-altitude illness after root canal therapy has not been described previously. A 44-year-old man is presented who skied to a 3333 m high peak in the Eastern Alps one day after he had undergone root canal therapy because of a tooth root infection. After 4 hours above 3000 m severe symptoms of high-altitude illness, including pulmonary oedema, developed. His condition improved after immediate descent. The next day he presented with local and general signs of infection which were successfully treated with gingival incisions and antibiotics. In conclusion, acute tooth root infection and root canal therapy may induce high-altitude illness at an altitude just above 3000 m.


Keywords: high-altitude illness; pulmonary oedema; root canal therapy; tooth root infection PMID:10715764

  17. Sources of plasma in the high altitude cusp

    NASA Astrophysics Data System (ADS)

    Peterson, W. K.; Trattner, K. J.

    2012-10-01

    Ambiguities introduced by the inconsistent definitions of the low and high altitude cusp lead to the inconsistency that at low altitudes the region commonly known as the cusp does not include boundary layer plasmas, but at high altitudes it does. Here we examine plasma data from two high altitude cusp intervals where ∼100 keV ionospheric ions were observed. We show that the data are an average over an interval that includes plasma from both boundary layer and newly injected solar wind plasmas. We find that the ∼100 keV ionospheric ions reported in the high altitude cusp are energized by well-known magnetospheric processes bringing energetic ions to the dayside boundary layers. We conclude that there is no need to postulate new processes associated with waves in diamagnetic cavities commonly found in the high altitude cusp to explain the observation of ∼100 keV ionospheric ions found there.

  18. Cardiovascular and renal effects of chronic exposure to high altitude.

    PubMed

    Hurtado, Abdias; Escudero, Elizabeth; Pando, Jackeline; Sharma, Shailendra; Johnson, Richard J

    2012-12-01

    Over 140 million people live at high altitude, defined as living at an altitude of 2400 m or more above sea level. Subjects living under these conditions are continuously living under hypoxic conditions and, depending on the population, various adaptations have developed. Interestingly, subjects living chronically at high altitude appear to have a decreased frequency of obesity, diabetes and coronary artery disease. However, these benefits on health are balanced by the frequent development of systemic and pulmonary hypertension. Recently, it has been recognized that subjects living at high altitude are at risk for developing high-altitude renal syndrome (HARS), which is a syndrome consisting of polycythemia, hyperuricemia, systemic hypertension and microalbuminuria, but with preserved glomerular filtration rate. More studies should be performed to characterize the mechanisms and etiology of HARS; as such studies may be of benefit not only to the high-altitude population, but also to better understanding of the renal consequences of acute and chronic hypoxia.

  19. High-altitude aerostats as astronomical platforms

    NASA Astrophysics Data System (ADS)

    Bely, Pierre Y.; Ashford, Robert; Cox, Charles D.

    1995-06-01

    The tropopause, typically at 16 to 18 km altitude at the lower latitudes, dips to 8 km in the polar regions. This makes the cold, dry, and nonturbulent lower stratosphere accessible to tethered aerostats. Tethered aerostats can fly as high as 12 km and are extremely reliable, lasting for many years. In contrast to free-flying balloons, they can stay on station for weeks at a time, and payloads can be safely recovered for maintenance and adjustment and relaunched in a matter of hours. We propose to use such a platform, located first in the Arctic (near Fairbanks, Alaska), and then later in the Antarctic, to operate a new technology 4-meter telescope with diffraction-limited performance in the near-IR. Thanks to the low ambient temperature (200 degrees K), thermal emission from the optics is of the same order as that of the zodiacal light in the 2 to 3 micron band. Since this wavelength interval is the darkest part of the zodiacal light spectrum from optical wavelengths to 100 microns, the combination of high resolution images and a very dark sky make it the spectral region of choice for observing the redshifted light from galaxies and clusters of galaxies at moderate to high redshifts.

  20. Microgravity combustion experiment using high altitude balloon.

    NASA Astrophysics Data System (ADS)

    Kan, Yuji

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

  1. Preparation for football competition at moderate to high altitude.

    PubMed

    Gore, C J; McSharry, P E; Hewitt, A J; Saunders, P U

    2008-08-01

    Analysis of approximately 100 years of home-and-away South American World Cup matches illustrate that football competition at moderate/high altitude (>2000 m) favors the home team, although this is more than compensated by the likelihood of sea-level teams winning at home against the same opponents who have descended from altitude. Nevertheless, the home team advantage at altitudes above approximately 2000 m may reflect that traditionally, teams from sea level or low altitude have not spent 1-2 weeks acclimatizing at altitude. Despite large differences between individuals, in the first few days at high altitude (e.g. La Paz, 3600 m) some players experience symptoms of acute mountain sickness (AMS) such as headache and disrupted sleep, and their maximum aerobic power (VO2max) is approximately 25% reduced while their ventilation, heart rate and blood lactate during submaximal exercise are elevated. Simulated altitude for a few weeks before competition at altitude can be used to attain partial ventilatory acclimation and ameliorated symptoms of AMS. The variety of simulated altitude exposures usually created with enriched nitrogen mixtures of air include resting or exercising for a few hours per day or sleeping approximately 8 h/night in hypoxia. Preparation for competition at moderate/high altitude by training at altitude is probably superior to simulated exposure; however, the optimal duration at moderate/high altitude is unclear. Preparing for 1-2 weeks at moderate/high altitude is a reasonable compromise between the benefits associated with overcoming AMS and partial restoration of VO2max vs the likelihood of detraining.

  2. High Altitude Observatory YBJ and ARGO Project

    NASA Astrophysics Data System (ADS)

    Tan, Y.; ARGO Collaboration

    A 5800 m2 RPC (Resistive Plate Chamber) full coverage air shower array is under construction in the YangBaJing Cosmic Ray Observatory, Tibet of China, by the ChinaItaly ARGO Collaboration. YBJ is a large flat grassland with an area 10 × 70 km2 at 4300m altitude, about 90 north west from Lhasa. Its nearby power station, asphalt road to Lhasa, passing railway (will be constructed during the coming 5 years), optical fiber link to the INTERNET, rare snow and other favourable weather conditions are well suitable for setting an Astrophysical Observatory here. The installation of a large area carpet-like detector in this peculiar site will allow one to perform an all-sky and high duty cycle study of high energy gamma rays from 100GeV to 50 TeV as well as accurate measurements on UHE cosmic rays. To insure the stable and uniform working condition of RPCs, a 104 M2 carpet hall was constructed, the RPC installation have be started in it since last November. The natural distribution and daily variation of temperature in the hall, the data concerning the performances of the installed RPCs, have been measured, the results are presented. ce

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

    NASA Astrophysics Data System (ADS)

    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 impact of moderate-altitude staging on pulmonary arterial hemodynamics after ascent to high altitude.

    PubMed

    Baggish, Aaron L; Fulco, Charles S; Muza, Stephen; Rock, Paul B; Beidleman, Beth; Cymerman, Allen; Yared, Kibar; Fagenholz, Peter; Systrom, David; Wood, Malissa J; Weyman, Arthur E; Picard, Michael H; Harris, N Stuart

    2010-01-01

    Staged ascent (SA), temporary residence at moderate altitude en route to high altitude, reduces the incidence and severity of noncardiopulmonary altitude illness such as acute mountain sickness. To date, the impact of SA on pulmonary arterial pressure (PAP) is unknown. We tested the hypothesis that SA would attenuate the PAP increase that occurs during rapid, direct ascent (DA). Transthoracic echocardiography was used to estimate mean PAP in 10 healthy males at sea level (SL, P(B) approximately 760 torr), after DA to simulated high altitude (hypobaric chamber, P(B) approximately 460 torr), and at 2 times points (90 min and 4 days) during exposure to terrestrial high altitude (P(B) approximately 460 torr) after SA (7 days, moderate altitude, P(B) approximately 548 torr). Alveolar oxygen pressure (Pao(2)) and arterial oxygenation saturation (Sao(2)) were measured at each time point. Compared to mean PAP at SL (mean +/- SD, 14 +/- 3 mmHg), mean PAP increased after DA to 37 +/- 8 mmHg (Delta = 24 +/- 10 mmHg, p < 0.001) and was negatively correlated with both Pao(2) (r(2) = 0.57, p = 0.011) and Sao(2) (r(2) = 0.64, p = 0.005). In comparison, estimated mean PAP after SA increased to only 25 +/- 4 mmHg (Delta = 11 +/- 6 mmHg, p < 0.001), remained unchanged after 4 days of high altitude residence (24 +/- 5 mmHg, p = not significant, or NS), and did not correlate with either parameter of oxygenation. SA significantly attenuated the PAP increase associated with continuous direct ascent to high altitude and appeared to uncouple PAP from both alveolar hypoxia and arterial hypoxemia.

  5. NASA/USRA high altitude reconnaissance aircraft

    NASA Technical Reports Server (NTRS)

    Richardson, Michael; Gudino, Juan; Chen, Kenny; Luong, Tai; Wilkerson, Dave; Keyvani, Anoosh

    1990-01-01

    At the equator, the ozone layer ranges from approximately 80,000 to 130,000+ feet which is beyond the capabilities of the ER-2, NASA's current high altitude reconnaissance aircraft. This project is geared to designing an aircraft that can study the ozone layer at the equator. This aircraft must be able to cruise at 130,000 lbs. of payload. In addition, the aircraft must have a minimum of a 6,000 mile range. The low Mach number, payload, and long cruising time are all constraints imposed by the air sampling equipment. A pilot must be able to take control in the event of unforseen difficulties. Three aircraft configurations were determined to be the most suitable for meeting the above requirements, a joined-wing, a bi-plane, and a twin-boom conventional airplane. The techniques used have been deemed reasonable within the limits of 1990 technology. The performance of each configuration is analyzed to investigate the feasibility of the project requirements. In the event that a requirement can not be obtained within the given constraints, recommendations for proposal modifications are given.

  6. The High-Altitude Water Cherenkov Observatory

    NASA Astrophysics Data System (ADS)

    Mostafá, Miguel A.

    2014-10-01

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

  7. The High Altitude Water Cherenkov (HAWC) Observatory

    NASA Astrophysics Data System (ADS)

    Springer, Wayne

    2014-06-01

    The High Altitude Water Cherenkov (HAWC) observatory is a continuously operated, wide field of view detector based upon a water Cherenkov technology developed by the Milagro experiment. HAWC observes, at an elevation of 4100 m on Sierra Negra Mountain in Mexico, extensive air showers initiated by gamma and cosmic rays. The completed detector will consist of 300 closely spaced water tanks each instrumented with four photomultiplier tubes that provide timing and charge information used to reconstruct energy and arrival direction. HAWC has been optimized to observe transient and steady emission from point as well as diffuse sources of gamma rays in the energy range from several hundred GeV to several hundred TeV. Studies in solar physics as well as the properties of cosmic rays will also be performed. HAWC has been making observations at various stages of deployment since completion of 10% of the array in summer 2012. A discussion of the detector design, science capabilities, current construction/commissioning status, and first results will be presented...

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

    PubMed

    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.

  9. Comparative aspects of high-altitude adaptation in human populations.

    PubMed

    Moore, L G; Armaza, F; Villena, M; Vargas, E

    2000-01-01

    The conditions and duration of high-altitude residence differ among high-altitude populations. The Tibetan Plateau is larger, more geographically remote, and appears to have been occupied for a longer period of time than the Andean Altiplano and, certainly, the Rocky Mountain region as judged by archaeological, linguistic, genetic and historical data. In addition, the Tibetan gene pool is less likely to have been constricted by small numbers of initial migrants and/or severe population decline, and to have been less subject to genetic admixture with lowland groups. Comparing Tibetans to other high-altitude residents demonstrates that Tibetans have less intrauterine growth retardation better neonatal oxygenation higher ventilation and hypoxic ventilatory response lower pulmonary arterial pressure and resistance lower hemoglobin concentrations and less susceptibility to CMS These findings are consistent with the conclusion that "adaptation" to high altitude increases with time, considering time in generations of high-altitude exposure. Future research is needed to compare the extent of IUGR and neonatal oxygenation in South American high-altitude residents of Andean vs. European ancestry, controlling for gestational age and other characteristics. Another fruitful line of inquiry is likely to be determining whether persons with CMS or other altitude-associated problems experienced exaggerated hypoxia during prenatal or neonatal life. Finally, the comparison of high-altitude populations with respect to the frequencies of genes involved in oxygen sensing and physiologic response to hypoxia will be useful, once candidate genes have been identified.

  10. The effect of high altitude on olfactory functions.

    PubMed

    Altundağ, Aytuğ; Salihoglu, Murat; Çayönü, Melih; Cingi, Cemal; Tekeli, Hakan; Hummel, Thomas

    2014-03-01

    It is known that high-altitude trips cause nasal congestion, impaired nasal mucociliary transport rate, and increased nasal resistance, due to decreased partial oxygen pressure and dry air. It is also known that olfactory perception is affected by barometric pressure and humidity. The aim of the present study was to investigate whether olfactory function changes in relation to high altitude in a natural setting. The present study included 41 volunteers with no history of chronic rhinosinusitis or nasal polyposis. The study group consisted of 31 men (76 %) and 10 women (24 %); the mean age of the study population was 38 ± 10 years. Olfactory testing was conducted using "Sniffin' Sticks" at a high altitude (2,200 ms) and at sea level. Odor test scores for threshold and identification were significantly better at sea level than at high altitude (p < 0.001). The major finding of this investigation was that olfactory functions are decreased at high altitudes.

  11. Travel to high altitude with pre-existing lung disease.

    PubMed

    Luks, A M; Swenson, E R

    2007-04-01

    The pathophysiology of high-altitude illnesses has been well studied in normal individuals, but little is known about the risks of high-altitude travel in patients with pre-existing lung disease. Although it would seem self-evident that any patient with lung disease might not do well at high altitude, the type and severity of disease will determine the likelihood of difficulty in a high-altitude environment. The present review examines whether these individuals are at risk of developing one of the main forms of acute or chronic high-altitude illness and whether the underlying lung disease itself will get worse at high elevations. Several groups of pulmonary disorders are considered, including obstructive, restrictive, vascular, control of ventilation, pleural and neuromuscular diseases. Attempts will be made to classify the risks faced by each of these groups at high altitude and to provide recommendations regarding evaluation prior to high-altitude travel, advice for or against taking such excursions, and effective prophylactic measures.

  12. Aging, High Altitude, and Blood Pressure: A Complex Relationship.

    PubMed

    Parati, Gianfranco; Ochoa, Juan Eugenio; Torlasco, Camilla; Salvi, Paolo; Lombardi, Carolina; Bilo, Grzegorz

    2015-06-01

    Parati, Gianfranco, Juan Eugenio Ochoa, Camilla Torlasco, Paolo Salvi, Carolina Lombardi, and Grzegorz Bilo. Aging, high altitude, and blood pressure: A complex relationship. High Alt Biol Med 16:97-109, 2015.--Both aging and high altitude exposure may induce important changes in BP regulation, leading to significant increases in BP levels. By inducing atherosclerotic changes, stiffening of large arteries, renal dysfunction, and arterial baroreflex impairment, advancing age may induce progressive increases in systolic BP levels, promoting development and progression of arterial hypertension. It is also known, although mainly from studies in young or middle-aged subjects, that exposure to high altitude may influence different mechanisms involved in BP regulation (i.e., neural central and reflex control of sympathetic activity), leading to important increases in BP levels. The evidence is less clear, however, on whether and to what extent advancing age may influence the BP response to acute or chronic high altitude exposure. This is a question not only of scientific interest but also of practical relevance given the consistent number of elderly individuals who are exposed for short time periods (either for leisure or work) or live permanently at high altitude, in whom arterial hypertension is frequently observed. This article will review the evidence available on the relationship between aging and blood pressure levels at high altitude, the pathophysiological mechanisms behind this complex association, as well as some questions of practical interest regarding antihypertensive treatment in elderly subjects, and the effects of antihypertensive drugs on blood pressure response during high altitude exposure.

  13. Improving oxygenation at high altitude: acclimatization and O2 enrichment.

    PubMed

    West, John B

    2003-01-01

    When lowlanders go to high altitude, the resulting oxygen deprivation impairs mental and physical performance, quality of sleep, and general well-being. This paper compares the effects of ventilatory acclimatization and oxygen enrichment of room air on the improvement of oxygenation as judged by the increase in the alveolar P(O2) and the reduction in equivalent altitude. The results show that, on the average, complete ventilatory acclimatization at an altitude of 5000 m increases the alveolar P(O2) by nearly 8 torr, which corresponds to a reduction in equivalent altitude of about 1000 m, although there is considerable individual variability. By comparison, oxygen enrichment to 27% at 5000 m can easily reduce the equivalent altitude to 3200 m, which is generally well tolerated. Because full ventilatory acclimatization at altitudes up to about 3600 m reduces the equivalent altitude to about 3000 m, oxygen enrichment is not justified for well-acclimatized persons. At an altitude of 4200 m, where several telescopes are located on the summit of Mauna Kea, full acclimatization reduces the equivalent altitude to about 3400 m, but the pattern of commuting probably would not allow this. Therefore, at this altitude, oxygen enrichment would be beneficial but is not essential. At higher altitudes such as 5050 m, where other telescopes are located or planned, the gain in oxygenation from acclimatization is insufficient to produce an adequate mental or physical performance for most work, and oxygen enrichment is highly desirable. Full ventilatory acclimatization requires at least a week of continuous exposure, although much of the improvement is seen in the first 2 days.

  14. Accuracy of Handheld Blood Glucose Meters at High Altitude

    PubMed Central

    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 studies reported bias in blood glucose measurements using different BGMs at high altitude. We hypothesized that glucose-oxidase based BGMs are more influenced by the lower atmospheric oxygen pressure at altitude than glucose dehydrogenase based BGMs. Methodology/Principal Findings Glucose measurements at simulated altitude of nine BGMs (six glucose dehydrogenase and three glucose oxidase BGMs) were compared to glucose measurement on a similar BGM at sea level and to a laboratory glucose reference method. Venous blood samples of four different glucose levels were used. Moreover, two glucose oxidase and two glucose dehydrogenase based BGMs were evaluated at different altitudes on Mount Kilimanjaro. Accuracy criteria were set at a bias <15% from reference glucose (when >6.5 mmol/L) and <1 mmol/L from reference glucose (when <6.5 mmol/L). No significant difference was observed between measurements at simulated altitude and sea level for either glucose oxidase based BGMs or glucose dehydrogenase based BGMs as a group phenomenon. Two GDH based BGMs did not meet set performance criteria. Most BGMs are generally overestimating true glucose concentration at high altitude. Conclusion At simulated high altitude all tested BGMs, including glucose oxidase based BGMs, did not show influence of low atmospheric oxygen pressure. All BGMs, except for two GDH based BGMs, performed within predefined criteria. At true high altitude one GDH based BGM had best precision and accuracy. PMID:21103399

  15. Travel to High Altitude Following Solid Organ Transplantation.

    PubMed

    Luks, Andrew M

    2016-09-01

    Luks, Andrew M. Clinician's corner: travel to high altitude following solid organ transplantation. High Alt Med Biol. 17:147-156, 2016.-As they regain active lifestyles following successful organ transplantation, transplant recipients may travel to high altitude for a variety of activities, including skiing, climbing, and trekking. This review is intended to provide information for medical providers who may encounter transplant patients seeking advice before planned high altitude travel or care for medical issues that develop during the actual sojourn. There is currently limited information in the literature about outcomes during high-altitude travel following solid organ transplantation, but the available evidence suggests that the physiologic responses to hypobaric hypoxia are comparable to those seen in nontransplanted individuals and well-selected transplant recipients with no evidence of organ rejection can tolerate ascents as high as 6200 m. All transplant recipients planning high-altitude travel should undergo pretravel assessment and counseling with an emphasis on the recognition, prevention, and treatment of altitude illness, as well as the importance of preventing infection and limiting sun exposure. Transplant recipients can use the standard medications for altitude illness prophylaxis and treatment, but the choice and dose of medication should take into account the patient's preexisting medication regimen and current renal function. With careful attention to these and other details, the healthy transplant recipient can safely experience the rewards of traveling in the mountains.

  16. Optimal birthweights in Peruvian populations at high and low altitudes.

    PubMed

    Beall, C M

    1981-11-01

    This study tests the hypothesis that optimum birthweight for survival is lower among hospital-born infants in Puno, Peru (altitude 3860 m) than that among their counterparts at low altitude in Tacna, Peru (altitude 600 m). The data are derived from hospital birth records for 1971 and 1972 and municipal death records for 1971 through 1973. Linking these records permits analysis of the patterns of mortality in relation to birthweight. Stabilizing selection upon birthweight is operating in both populations. The high altitude population has a lower mean birthweight and a lower optimal birthweight. The Puno population is closer to its optimal birthweight distribution and, as a result of mortality during infancy, is approaching its optimum birthweight distribution for survival more rapidly than the Tacna population. It appears that the high altitude Puno population may well be adapted to its environment in the sense that there is less selective mortality on birthweight phenotypes.

  17. Podoverine A--a novel microtubule destabilizing natural product from the Podophyllum species.

    PubMed

    Tran, Tuyen Thi Ngoc; Gerding-Reimers, Claas; Schölermann, Beate; Stanitzki, Bettina; Henkel, Thomas; Waldmann, Herbert; Ziegler, Slava

    2014-09-15

    Natural products represent compound classes with high chemical and structural diversity and various biological activities. Libraries based on natural products are valuable starting point in the search for novel biologically active substances. Here we report on the identification of the natural product podoverine A from the plant Podophyllum versipelle Hance as a novel tubulin-acting agent. A natural product compound collection was subjected to a high-content screen that monitors changes in cytoskeleton and DNA and podoverine A was identified as inhibitor of mitosis. This natural product causes mitotic arrest and inhibits microtubule polymerization in vitro and in cells by targeting the vinca binding site on tubulin.

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

    PubMed

    Lundby, Carsten; Calbet, Jose A L

    2016-01-01

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

  19. DLR HABLEG- High Altitude Balloon Launched Experimental Glider

    NASA Astrophysics Data System (ADS)

    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.

  20. Highly Resolved Aerosol Measurements from High Altitude Platforms

    NASA Technical Reports Server (NTRS)

    Wilson, James Charles

    1999-01-01

    The University of Denver agreed to develop and fabricate two instruments for the characterization of submicron aerosol. The instruments were to be light weight for use on remotely-piloted aircraft or balloons. The instruments were to provide accurate size measurements of size distributions in the size range from 0.07 to 2 micrometers in diameter and concentration measurements in the size range approximately 0.01 to 2 micrometers in diameter. The instruments constructed under this cooperative agreement respond quite nearly as expected and meet the objective of being light and compact. One has been used for ground based and low altitude studies and the other will be deployed in high altitude studies this winter.

  1. Sleep quality among elderly high-altitude dwellers in Ladakh.

    PubMed

    Sakamoto, Ryota; Okumiya, Kiyohito; Norboo, Tsering; Tsering, Norboo; Yamaguchi, Takayoshi; Nose, Mitsuhiro; Takeda, Shinya; Tsukihara, Toshihiro; Ishikawa, Motonao; Nakajima, Shun; Wada, Taizo; Fujisawa, Michiko; Imai, Hissei; Ishimoto, Yasuko; Kimura, Yumi; Fukutomi, Eriko; Chen, Wenling; Otsuka, Kuniaki; Matsubayashi, Kozo

    2017-03-01

    It has been already known that people who temporarily stay at high altitude may develop insomnia as a symptom of acute mountain sickness. However, much less is known about people living at high altitude. The aim of this study was to determine the effect of high altitude environment on sleep quality for the elderly who have been living at high altitude for their whole lives. A cross-sectional study was conducted in Domkhar valley at altitudes of 2800-4200m, Ladakh. Sleep quality was assessed using Insomnia Severity Index (ISI). Measurement items include body mass index, blood pressure, blood sugar, hemoglobin, timed Up and Go test, oxygen saturation during wakefulness, respiratory function test, Oxford Knee Score (OKS), and Geriatric Depression Scale (GDS), and so on. The participants were Ladakhi older adults aged 60 years or over (n=112) in Domkhar valley. The participation rate was 65.1% (male: female=47:65, mean age: 71.3 years and 67.9 years, respectively). The prevalence of the high score of ISI (8 or more) was 15.2% (17 out of 112). Altitude of residence was significantly correlated with ISI. Stepwise multiple regression analysis showed that OKS and altitude of residence were significantly related with ISI.

  2. The effect of high altitude on nasal nitric oxide levels.

    PubMed

    Altundag, Aytug; Salihoglu, Murat; Cayonu, Melih; Cingi, Cemal; Tekeli, Hakan; Hummel, Thomas

    2014-09-01

    The aim of the present study was to investigate whether nasal nitric oxide (nNO) levels change in relation to high altitude in a natural setting where the weather conditions were favorable. The present study included 41 healthy volunteers without a history of acute rhinosinusitis within 3 weeks and nasal polyposis. The study group consisted of 31 males (76 %) and 10 females (24 %) and the mean age of the study population was 38 ± 10 years. The volunteers encamped for 2 days in a mountain village at an altitude of 1,500 m above sea level (masl) and proceeded to highlands at an altitude of 2,200 masl throughout the day. The measurements of nNO were done randomly, either first at the mountain village or at sea level. Each participant had nNO values both at sea level and at high altitude at the end of the study. The nNO values of sea level and high altitude were compared to investigate the effect of high altitude on nNO levels. The mean of average nNO measurements at the high altitude was 74.2 ± 41 parts-per-billion (ppb) and the mean of the measurements at sea level was 93.4 ± 45 ppb. The change in nNO depending on the altitude level was statistically significant (p < 0.001). The current investigation showed that nNO levels were decreased at high altitude even if the weather conditions were favorable, such as temperature, humidity, and wind.

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

    PubMed

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

    2010-01-01

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

  4. Travelling to new heights: practical high altitude medicine.

    PubMed

    Plant, Tracie; Aref-Adib, Golnar

    2008-06-01

    Over 40 million people travel to high altitude for both work and pleasure each year, and all of them are at risk of the acute effects of hypoxia. This article reviews the prevention, diagnostic features and treatments of these illnesses.

  5. 33. GENERAL HIGH ALTITUDE AERIAL VIEW OF COMPLEX AND GENERAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    33. GENERAL HIGH ALTITUDE AERIAL VIEW OF COMPLEX AND GENERAL SETTING. October 1982 - Mississippi River 9-Foot Channel Project, Lock & Dam No. 15, Upper Mississipi River (Arsenal Island), Rock Island, Rock Island County, IL

  6. 13. GENERAL HIGH ALTITUDE AERIAL VIEW OF COMPLEX AND GENERAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. GENERAL HIGH ALTITUDE AERIAL VIEW OF COMPLEX AND GENERAL SETTING. October 1982 - Mississippi River 9-Foot Channel Project, Lock & Dam No. 17, Upper Mississippi River, New Boston, Mercer County, IL

  7. Radioprotective mechanism of Podophyllum hexandrum during spermatogenesis.

    PubMed

    Samanta, N; Kannan, K; Bala, M; Goel, H C

    2004-12-01

    RP-1, a herbal preparation of Podophyllum hexandrum has already been reported to provide protection against whole body lethal gamma irradiation (10 Gy). It has also been reported to render radioprotection to germ cells during spermatogenesis. Present study was undertaken to unravel the cellular and molecular mechanism of action of RP-1 on testicular system in strain 'A' mice. Various antioxidant parameters such as thiol content, glutathione peroxidase (GPx), glutathione reductase (GR), glutathione-S-transferase (GST) enzyme activity, lipid peroxidation (LPO) and total protein levels were investigated. Thiol content was seen to increase significantly (p < 0.05) in both RP-1 alone and RP-1 pretreated irradiated groups over the irradiated groups at 8, 16 and 24 h. Irradiation (10 Gy) significantly decreased GPx, GST and GR activity in comparison to untreated control but RP-1 treatment before irradiation significantly (p < 0.05) countered radiation-induced decrease in the activity of these enzymes. Radiation-induced LPO was also found to be reduced at all time intervals by RP-1 treatment before irradiation. As compared to irradiated group the protein content in testicular tissue was increased in RP-1 pretreated irradiated group at 4 and 16 h significantly (p < 0.05). Comets revealed by single-cell gel electrophoresis were significantly longer (p < 0.001) in irradiated mice than in unirradiated control. RP-1 treatment before irradiation, however, rendered significant increase (p < 0.05) in comet length over the corresponding control and irradiated group initially at 4 h but at later time points, this was reduced significantly (p < 0.01) as compared to the irradiated group. RP-1 treatment alone rendered shorter comets at 8, 16 and 24 h than irradiated groups (p < 0.001). This study implies that RP-1 offers radioprotection at biochemical and cytogenetic level by protecting antioxidant enzymes, reducing LPO and increasing thiol content.

  8. Effects of High Terrestrial Altitude on Military Performance

    DTIC Science & Technology

    1989-04-18

    Title Effects of High Terrestrial Altitude on Military Performance Author( s ) Louis E. Banderet and Richard L. Burse Intended for publication in Handbook...34’- <-𔃾 DA UJ 2496 PRIVOUS EDITIONS WILL II USED C . S fnt Effects of High Terrestrial Altitude on Military Performance 1 2 Louis E. Banderet...inadequate oxygen which can ad- versely affect military performance ( Disease threat, 1979; U.S. Army, 1975). Much information of military importance about

  9. Energy metabolism and the high-altitude environment.

    PubMed

    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.

  10. Electroretinographic assessment of retinal function at high altitude.

    PubMed

    Schatz, Andreas; Willmann, Gabriel; Fischer, M Dominik; Schommer, Kai; Messias, André; Zrenner, Eberhart; Bartz-Schmidt, Karl-Ulrich; Gekeler, Florian

    2013-08-01

    Although hypoxia plays a key role in the pathophysiology of many common and well studied retinal diseases, little is known about the effects of high-altitude hypoxia on retinal function. The aim of the present study was to assess retinal function during exposure to high-altitude hypoxia using electroretinography (ERG). This work is related to the Tübingen High Altitude Ophthalmology (THAO) study. Electroretinography was performed in 14 subjects in Tübingen, Germany (341 m) and at high altitude at La Capanna Regina Margherita, Italy (4,559 m) using an extended protocol to assess functional integrity of various retinal layers. To place findings in the context of acute mountain sickness, correlations between ERG measurements and oxygen saturation, heart rate, and scores of acute mountain sickness (AMS) were calculated. At high altitude, the maximum response of the scotopic sensitivity function, the implicit times of the a- and b-wave of the combined rod-cone responses, and the implicit times of the photopic negative responses (PhNR) were significantly altered. A-wave slopes and i-waves were significantly decreased at high altitude. The strongest correlation was found for PhNR and O2 saturation (r = 0.68; P < 0.05). Of all tested correlations, only the photopic b-wave implicit time (10 cd·s/m(2)) was significantly correlated with severity of AMS (r = 0.57; P < 0.05). ERG data show that retinal function of inner, outer, and ganglion cell layer is altered at high-altitude hypoxia. Interestingly, the most affected ERG parameters are related to combined rod-cone responses, which indicate that phototransduction and visual processing, especially under conditions of rod-cone interaction, are primarily affected at high altitude.

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

    PubMed

    Richalet, Jean-Paul; Lhuissier, François J

    2015-06-01

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

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

    PubMed

    Qiu, Qiang; Zhang, Guojie; Ma, Tao; Qian, Wubin; Wang, Junyi; Ye, Zhiqiang; Cao, Changchang; Hu, Quanjun; Kim, Jaebum; Larkin, Denis M; Auvil, Loretta; Capitanu, Boris; Ma, Jian; Lewin, Harris A; Qian, Xiaoju; Lang, Yongshan; Zhou, Ran; Wang, Lizhong; Wang, Kun; Xia, Jinquan; Liao, Shengguang; Pan, Shengkai; Lu, Xu; Hou, Haolong; Wang, Yan; Zang, Xuetao; Yin, Ye; Ma, Hui; Zhang, Jian; Wang, Zhaofeng; Zhang, Yingmei; Zhang, Dawei; Yonezawa, Takahiro; Hasegawa, Masami; Zhong, Yang; Liu, Wenbin; Zhang, Yan; Huang, Zhiyong; Zhang, Shengxiang; Long, Ruijun; Yang, Huanming; Wang, Jian; Lenstra, Johannes A; Cooper, David N; Wu, Yi; Wang, Jun; Shi, Peng; Wang, Jian; Liu, Jianquan

    2012-07-01

    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. Here, we present the draft genome sequence of a female domestic yak generated using Illumina-based technology at 65-fold coverage. Genomic comparisons between yak and cattle identify an expansion in yak of gene families related to sensory perception and energy metabolism, as well as an enrichment 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.

  13. Global assessment of high-altitude wind power

    NASA Astrophysics Data System (ADS)

    Archer, C. L.; Caldeira, K.

    2008-12-01

    Wind speed generally increases with altitude to the tropopause; hence, the power available in high-altitude winds is enormous, especially near the jet streams. We assess for the first time the available wind power resource worldwide at altitudes between 500 and 12,000 m. The highest wind power densities are found near 10,000 m over Japan and eastern China, the eastern coast of the United States, southern Australia, and north-eastern Africa. Below 1000 m, the best locations are the southern tip of South America, the coasts along the northern Pacific and Atlantic oceans, the central-eastern coast of Africa, and the north-eastern coast of South America. Because jet streams vary locally and seasonally, however, the high-altitude wind power resource is less steady than needed for baseload power. However, dynamically reaching the height with the highest winds, increasing the area covered with high-altitude devices, and using batteries for storage can effectively reduce intermittency. When high-altitude wind power devices are distributed uniformly throughout the entire atmosphere, numerical simulations show negligible effects on the global climate for low densities, but surface cooling, decreased precipitation, and greater sea ice cover for high densities.

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

    SciTech Connect

    Fry, R.J.M.

    1993-01-01

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

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

    SciTech Connect

    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.

  16. Pulmonary vascular disease in a rabbit a high altitude

    NASA Astrophysics Data System (ADS)

    Heath, Donald; Williams, David; Rios-Datenz, Jaime; Gosney, John

    1990-03-01

    A male weanling rabbit of the New Zealand White strain, born and living at an altitude of 3800 m in La Paz, Bolivia, developed right ventricular hypertrophy. This was found to be associated with growth of vascular smooth muscle cells in the intima of pulmonary arterioles, and contrasted with muscularization of the walls of pulmonary arterioles, without extension into the intima, found in a healthy, high-altitude control rabbit of the same strain. A low-altitude control showed no such muscularization. It is concluded that alveolar hypoxia, acting directly or through an intermediate agent, is a growth factor for vascular smooth muscle cells in pulmonary arterioles. This is the first report of pulmonary vascular disease due to high altitude in rabbits.

  17. Description of SHARC: The Strategic High-Altitude Radiance Code.

    DTIC Science & Technology

    1989-08-16

    for Paths from 60 to 300 km altitude in he 2-40 _.m spectral region. It models r-adiation due to NLTE (Non-Local Thermodynamic quilibrium) molecular...2 HIGH-ALTITUDE INFRARED RADIATION CONCEPTS ... ....... 4 2.1 Non-Local Thermodynamic Equilibrium .... ........ 4 2.2 Vibrational Temperature...Non-Local Thermodynamic Equilibrium) populations of higher vibrational states are included in the calculation. The equivalent-width, line-by-line LBL

  18. Effect of high altitude on protein metabolism in Bolivian children.

    PubMed

    San Miguel, Jose L; Spielvogel, Hilde; Berger, Jacques; Araoz, Mauricio; Lujan, Carmen; Tellez, Wilma; Caceres, Esperanza; Gachon, Pierre; Coudert, Jean; Beaufrere, Bernard

    2002-01-01

    In Bolivia, malnutrition in children is a major health problem that may be caused by inadequate protein, energy, and micronutrient intake; exposure to bacterial and parasitic infections; and life in a multistress environment (high altitude, cold, cosmic radiation, low ambient humidity). However, no data on protein absorption and utilization at high altitude were available. Therefore, we evaluated the effect of altitude on protein metabolism in Bolivian children. We measured protein utilization using leucine labeled with a stable isotope ((13)C) in two groups of healthy prepubertal children matched for age. Group 1 (n = 10) was examined at high altitude (HA) in La Paz (3600 m), and group 2 (n = 10) at low altitude (LA) in Santa Cruz (420 m). The nutritional status did not differ between groups but, as was to be expected, the HA group had higher hemoglobin concentration than the LA group. The children consumed casein that was intrinsically labeled with L-(1-(13)C) leucine and expired (13)CO(2) was analyzed. Samples of expired air were measured by isotope ratio mass spectrometer in Clermont-Ferrand. It was found that cumulative leucine oxidation ((13)CO(2)) at 300 min after ingestion was 19.7 +/- 4.9% at HA and 25.2 +/- 3.2% at LA. These results showed that protein absorption and/or utilization is significantly affected by altitude.

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

    PubMed

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

    2013-01-01

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

  20. SHARP: Subsonic High Altitude Research Platform

    NASA Technical Reports Server (NTRS)

    Beals, Todd; Burton, Craig; Cabatan, Aileen; Hermano, Christine; Jones, Tom; Lee, Susan; Radloff, Brian

    1991-01-01

    The Universities Space Research Association is sponsoring an undergraduate program which is geared to designing an aircraft that can study the ozone layer at the equator. This aircraft must be able to satisfy four mission profiles. Mission one is a polar mission that ranges from Chile to the South Pole and back to Chile, a total range of 6000 n.mi. at 100,000 ft with a 2500 lb payload. The second mission is also a polar mission, with an altitude of 70,000 ft and an increased payload of 4000 lbs. For the third mission, the aircraft will takeoff at NASA Ames, cruise at 100,000 ft carrying a 2500 lb payload, and land at Puerto Montt, Chile. The final mission requires the aircraft to take off at NASA Ames, cruise at 100,000 ft with a 1000 lb payload, make an excursion to 120,000 ft, and land at Howard AFB, Panama. Three missions require that a subsonic Mach number be maintained due to constraints imposed by the air sampling equipment. The aircraft need not be manned for all four missions. Three aircraft configurations have been determined to be the most suitable for meeting the above requirements. In the event that a requirement cannot be obtained within the given constraints, recommendations for proposal modifications are given.

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

    PubMed Central

    Shah, Neeraj M; Hussain, Sidra; Cooke, Mark; O’Hara, John P; Mellor, Adrian

    2015-01-01

    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. PMID:26445563

  2. Long-Term Exposure to High Altitude Affects Conflict Control in the Conflict-Resolving Stage.

    PubMed

    Ma, Hailin; Wang, Yan; Wu, Jianhui; Wang, Baoxi; Guo, Shichun; Luo, Ping; Han, Buxin

    2015-01-01

    The neurocognitive basis of the effect of long-term high altitude exposure on conflict control is unclear. Event related potentials (ERPs) were recorded in a flanker task to investigate the influence of high altitude on conflict control in the high-altitude group (who had lived at high altitude for three years but were born at low altitude) and the low-altitude group (living in low altitude only). Although altitude effect was not significant at the behavioral level, ERPs showed cognitive conflict modulation. The interaction between group and trial type was significant: P3 amplitude was greater in the low-altitude group than in the high-altitude group in the incongruent trial. This result suggests that long-term exposure to high altitude affects conflict control in the conflict-resolving stage, and that attentional resources are decreased to resist the conflict control in the high-altitude group.

  3. Dilated hearts at high altitude: words from on high.

    PubMed

    Lankford, Harvey V; Swenson, Erik R

    2014-12-01

    From the time of the turn of the twentieth century, dilated hearts and presumed cardiac fatigue in expeditionary climbers and scientists have been the subject of much commentary in the medical and mountaineering literature. Although largely attributed by most, but not all, to left heart strain, the description of dilated hearts in these accounts is clearly that of right heart dilation as a consequence of high and sustained hypoxic pulmonary vasoconstriction with hypertensive remodeling. This essay will feature quotations from the writings of high altitude pioneers about dilated, strained, or enlarged hearts. It will give some brief physiology of the right side of the heart as background, but will focus on the words of mountaineers and mountaineering physicians as color commentary.

  4. Strenuous physical exercise inhibits granulocyte activation induced by high altitude.

    PubMed

    Choukèr, Alexander; Demetz, Florian; Martignoni, André; Smith, Leslie; Setzer, Florian; Bauer, Andreas; Hölzl, Joseph; Peter, Klaus; Christ, Frank; Thiel, Manfred

    2005-02-01

    To test the hypothesis of whether strenuous physical exercise inhibits neutrophils that can get activated by hypobaric hypoxia, we analyzed the effects of both high altitude and strenuous exercise alone and in combination on potentially cytotoxic functions of granulocytes in healthy volunteers (n = 12 men; average age 27.6 yr; range 24-38 yr). To this end, a field study was prospectively performed with an open-labeled within-subject design comprising three protocols. Protocol I (high altitude) involved a helicopter ascent, overnight stay at 3,196 m, and descent on the following day. Protocol II (physical exercise) involved hiking below an altitude of 2,100 m with repetitive ascents amounting to a total ascent to that of protocol III. Protocol III (combination of physical exercise and high altitude) involved climbing from 1,416 to 3,196 m, stay overnight, and descent on the following day. In protocol I, number of granulocytes did not change, but potentially cytotoxic functions of cells (CD18 expression and superoxide production) were early and significantly upregulated. In protocol II, subjects developed granulocytosis, but functions of cells were inhibited. In protocol III, granulocytosis occurred at higher values than those observed under protocol II. Potentially cytotoxic functions of cells, however, were strongly inhibited again. In conclusion, high altitude alone, even moderate in extent, can activate potentially cytotoxic functions of circulating granulocytes. Strenuous physical exercise strongly inhibits this activation, which may give protection from an otherwise inflammatory injury.

  5. Physiological adaptation of the cardiovascular system to high altitude.

    PubMed

    Naeije, Robert

    2010-01-01

    Altitude exposure is associated with major changes in cardiovascular function. The initial cardiovascular response to altitude is characterized by an increase in cardiac output with tachycardia, no change in stroke volume, whereas blood pressure may temporarily be slightly increased. After a few days of acclimatization, cardiac output returns to normal, but heart rate remains increased, so that stroke volume is decreased. Pulmonary artery pressure increases without change in pulmonary artery wedge pressure. This pattern is essentially unchanged with prolonged or lifelong altitude sojourns. Ventricular function is maintained, with initially increased, then preserved or slightly depressed indices of systolic function, and an altered diastolic filling pattern. Filling pressures of the heart remain unchanged. Exercise in acute as well as in chronic high-altitude exposure is associated with a brisk increase in pulmonary artery pressure. The relationships between workload, cardiac output, and oxygen uptake are preserved in all circumstances, but there is a decrease in maximal oxygen consumption, which is accompanied by a decrease in maximal cardiac output. The decrease in maximal cardiac output is minimal in acute hypoxia but becomes more pronounced with acclimatization. This is not explained by hypovolemia, acid-bases status, increased viscosity on polycythemia, autonomic nervous system changes, or depressed systolic function. Maximal oxygen uptake at high altitudes has been modeled to be determined by the matching of convective and diffusional oxygen transport systems at a lower maximal cardiac output. However, there has been recent suggestion that 10% to 25% of the loss in aerobic exercise capacity at high altitudes can be restored by specific pulmonary vasodilating interventions. Whether this is explained by an improved maximum flow output by an unloaded right ventricle remains to be confirmed. Altitude exposure carries no identified risk of myocardial ischemia in

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

    NASA Technical Reports Server (NTRS)

    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.

  7. Microcomputer-controlled high-altitude data aquisition system

    NASA Astrophysics Data System (ADS)

    1985-05-01

    A new microcomputer controlled high altitude data acquisition system was developed. The system provides a new technique for data acquisition from China's astronomical, meteorological and other high altitude experiments and opens up new territory in microcomputer applications. This microcomputer controlled high altitude data acquisition system is made up of a Z80 single board computer, 10 K memory expansion board, and keyboard and display board which can collect 16 analog signals simultaneously, and through analog/digital conversion can convert external analog signals into digital signals then encode them in a certain form through program modulation and store them on audio cassette. The data is immediately retrieved from the tape and sent to the surface microcomputer system for data processing and analysis.

  8. [Medical certification for high altitude travel and scuba diving].

    PubMed

    Wuillemin, Timothée; Dos Santos Bragança, Angel; Ziltener, Jean-Luc; Berney, Jean-Yves; Lanier, Cédric

    2014-09-24

    People are more and more looking for adventures and discovery of unusual locations. Journeys to high altitude and scuba diving are part of these activities and their access has become easier for a lot of people not necessarily experienced with their dangers. The general practitioner will have to be able to deliver some advices and recommendations to his patients about the risks related to these activities and their ability to practice them. He will also have to deliver some certificates of medical fitness to dive. This paper proposes a brief review of the most important medical aspects to know about high altitude and scuba diving.

  9. DE-1 observations of counterstreaming electrons at high altitudes

    NASA Astrophysics Data System (ADS)

    Lin, C. S.; Burch, J. L.; Winningham, J. D.; Menietti, J. D.; Hoffman, R. A.

    1982-09-01

    Observations of plasma at altitudes of 2-3 earth radii with the High Altitude Plasma Instrument (HAPI) on DE-1 indicate two distinct types of counterstreaming electron events. The type 1 event is characterized by two Maxwellian distribution functions, an isotropic high-temperature component and a field-aligned low temperature component. The type 2 event is distinguished by beams parallel and antiparallel to the magnetic field direction. The observations suggest two distinct mechanisms for accelerating counterstreaming electrons. Type 1 events appear to involve wave-particle interactions while type 2 events imply direct acceleration by oppositely-directed electric fields pointing toward the satellite along magnetic field lines.

  10. DE-1 observations of counterstreaming electrons at high altitudes

    SciTech Connect

    Lin, C.S.; Burch, J.L.; Winningham, J.D.; Menietti, J.D.; Hoffman, R.A.

    1982-09-01

    Observations of plasma at altitudes of 2-3 R/sub E/ with the High Altitude Plasma Instrument (HAPI) on DE-1 indicate two distinct types of counterstreaming electron events. The type 1 event is characterized by two Maxwellian distribution functions, an isotropic high-temperature component and a field-aligned low temperature component. The type 2 event is distinguished by beams parallel and antiparallel to the magnetic field direction. The observations suggest two distinct mechanisms for accelerating counterstreaming electrons. Type 1 events appear to involve wave-particle interactions while type 2 events imply direct acceleration by oppositely-directed electric fields pointing toward the satellite along magnetic field lines.

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

    NASA Astrophysics Data System (ADS)

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

    1987-09-01

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

  12. Observations of High-altitude Negative Lightning Leaders

    NASA Astrophysics Data System (ADS)

    Edens, H. E.

    2011-12-01

    On 20 August 2010 a high-speed video recording was made of a bolt-from-the-blue (BFB) lightning flash where the negative leader exited the cloud near 9 km altitude and could be observed in clear air along most of its path to ground. The observation was augmented by data from Langmuir Laboratory's 3-D Lightning Mapping Array (LMA) as well as slow and fast Delta-E and broadband (up to 100 MHz) electric field waveform recordings. The various data sets are correlated in time and time-correlated LMA data is overlaid on the video frames, yielding a spectacular animation of a negative leader as it propagates from 9 km altitude down into air of increasingly higher pressure, contacting ground at 1.5 km altitude. At 9 km altitude, the tip of the negative leader exhibits impulsive emissions of light and retrograde luminosity waves that are seen to travel backward along the channel, away from the leader tip. As the leader propagates down in altitude the light emissions from the leader tip become more continuous in nature and the leader starts branching profusely. The leader velocity, on the order of 10^5 m/s, did not appear to change significantly. At the same storm, 30 minutes before the BFB flash occurred, a photograph was obtained of another negative leader from an intracloud (IC) flash that exited the cloud near the top, propagated several kilometers upward along a slanted path and terminated in clear air at 11 km altitude. The photograph was made with a Nikon D700 digital camera set at high sensitivity. The individual leader steps, which are on the order of 200 m length, are resolved as relatively straight segments of channel between sharp bends. At each bend (or kink) in the channel, clusters of 5 to 8 blue streamer filaments occur that are on the order of 100 m length. Small branches occur at most of the channel bends. One bend in the channel is accompanied by a space stem with blue streamers at both ends. The positive streamer emanating from the space stem and reaching

  13. Growth and nutritional status of Tibetan children at high altitude.

    PubMed

    Argnani, Lisa; Cogo, Annalisa; Gualdi-Russo, Emanuela

    2008-09-01

    Growth and development are clearly affected by high-altitude exposure to hypoxia, nutritional stress, cold or a combination of these factors. Very little research has been conducted on the growth and nutritional status of children living on the Tibetan Plateau. The present study evaluated the environmental impact on human growth by analyzing anthropometric characteristics of Tibetan children aged 8-14, born and raised above 4000 m altitude on the Himalayan massif in the prefecture of Shegar in Tibet Autonomous Region. Data on anthropometric traits, never measured in this population, were collected and the nutritional status was assessed. A reference data set is provided for this population. There was no evidence of wasting but stunting was detected (28.3%). Children permanently exposed to the high-altitude environment above 4000 m present a phenotypic form of adaptation and a moderate reduction in linear growth. However, it is also necessary to consider the effects of socioeconomic deprivation.

  14. Admixture facilitates genetic adaptations to high altitude in Tibet

    PubMed Central

    Jeong, Choongwon; Alkorta-Aranburu, Gorka; Basnyat, Buddha; Neupane, Maniraj; Witonsky, David B.; Pritchard, Jonathan K.; Beall, Cynthia M.; Di Rienzo, Anna

    2015-01-01

    Admixture is recognized as a widespread feature of human populations, renewing interest in the possibility that genetic exchange can facilitate adaptations to new environments. Studies of Tibetans revealed candidates for high-altitude adaptations in the EGLN1 and EPAS1 genes, associated with lower hemoglobin concentration. However, the history of these variants or that of Tibetans remains poorly understood. Here, we analyze genotype data for the Nepalese Sherpa, and find that Tibetans are a mixture of ancestral populations related to the Sherpa and Han Chinese. EGLN1 and EPAS1 genes show a striking enrichment of high-altitude ancestry in the Tibetan genome, indicating that migrants from low altitude acquired adaptive alleles from the highlanders. Accordingly, the Sherpa and Tibetans share adaptive hemoglobin traits. This admixture-mediated adaptation shares important features with adaptive introgression. Therefore, we identify a novel mechanism, beyond selection on new mutations or on standing variation, through which populations can adapt to local environments. PMID:24513612

  15. Reduced oxygen at high altitude limits maximum size.

    PubMed

    Peck, L S; Chapelle, G

    2003-11-07

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

  16. Electrocardiography in people living at high altitude of Nepal

    PubMed Central

    Aryal, Nirmal; Weatherall, Mark; Bhatta, Yadav Kumar Deo; Mann, Stewart

    2017-01-01

    Objective The main objective of this study was to estimate the prevalence of coronary heart disease (CHD) of high-altitude populations in Nepal determined by an ECG recordings and a medical history. Methods We carried out a cross-sectional survey of cardiovascular disease and risk factors among people living at four different altitude levels, all above 2800 m, in the Mustang and Humla districts of Nepal. 12-lead ECGs were recorded on 485 participants. ECG recordings were categorised as definitely abnormal, borderline or normal. Results No participant had Q waves to suggest past Q-wave infarction. Overall, 5.6% (95% CI 3.7 to 8.0) of participants gave a self-report of CHD. The prevalence of abnormal (or borderline abnormal) ECG was 19.6% (95% CI 16.1 to 23.4). The main abnormalities were: right axis deviation in 5.4% (95% CI 3.5 to 7.7) and left ventricular hypertrophy by voltage criteria in 3.5% (95% CI 2.0 to 5.5). ECG abnormalities were mainly on the left side of the heart for Mustang participants (Tibetan origin) and on the right side for Humla participants (Indo-Aryans). There was a moderate association between the probability of abnormal (or borderline abnormal) ECG and altitude when adjusted for potential confounding variables in a multivariate logistic model; with an OR for association per 1000 m elevation of altitude of 2.83 (95% CI 1.07 to 7.45), p=0.03. Conclusions Electrocardiographic evidence suggests that although high-altitude populations do not have a high prevalence of CHD, abnormal ECG findings increase by altitude and risk pattern varies by ethnicity. PMID:28243317

  17. Infrared astronomy research and high altitude observations

    NASA Technical Reports Server (NTRS)

    Jones, B.; Stein, W. A.; Willner, S. P.; Soifer, B. T.

    1984-01-01

    Highlights are presented of studies of the emission mechanisms in the 4 to 8 micron region of the spectrum using a circular variable filter wheel spectrometer with a PbSnTe photovoltaic detector. Investigations covered include the spectroscopy of planets, stellar atmospheres, highly obscured objects in molecular clouds, planetary nebulae, H2 regions, and extragalactic objects.

  18. Adaptation of iron requirement to hypoxic conditions at high altitude.

    PubMed

    Gassmann, Max; Muckenthaler, Martina U

    2015-12-15

    Adequate acclimatization time to enable adjustment to hypoxic conditions is one of the most important aspects for mountaineers ascending to high altitude. Accordingly, most reviews emphasize mechanisms that cope with reduced oxygen supply. However, during sojourns to high altitude adjustment to elevated iron demand is equally critical. Thus in this review we focus on the interaction between oxygen and iron homeostasis. We review the role of iron 1) in the oxygen sensing process and erythropoietin (Epo) synthesis, 2) in gene expression control mediated by the hypoxia-inducible factor-2 (HIF-2), and 3) as an oxygen carrier in hemoglobin, myoglobin, and cytochromes. The blood hormone Epo that is abundantly expressed by the kidney under hypoxic conditions stimulates erythropoiesis in the bone marrow, a process requiring high iron levels. To ensure that sufficient iron is provided, Epo-controlled erythroferrone that is expressed in erythroid precursor cells acts in the liver to reduce expression of the iron hormone hepcidin. Consequently, suppression of hepcidin allows for elevated iron release from storage organs and enhanced absorption of dietary iron by enterocytes. As recently observed in sojourners at high altitude, however, iron uptake may be hampered by reduced appetite and gastrointestinal bleeding. Reduced iron availability, as observed in a hypoxic mountaineer, enhances hypoxia-induced pulmonary hypertension and may contribute to other hypoxia-related diseases. Overall, adequate systemic iron availability is an important prerequisite to adjust to high-altitude hypoxia and may have additional implications for disease-related hypoxic conditions.

  19. A genetic mechanism for Tibetan high-altitude adaptation.

    PubMed

    Lorenzo, Felipe R; Huff, Chad; Myllymäki, Mikko; Olenchock, Benjamin; Swierczek, Sabina; Tashi, Tsewang; Gordeuk, Victor; Wuren, Tana; Ri-Li, Ge; McClain, Donald A; Khan, Tahsin M; Koul, Parvaiz A; Guchhait, Prasenjit; Salama, Mohamed E; Xing, Jinchuan; Semenza, Gregg L; Liberzon, Ella; Wilson, Andrew; Simonson, Tatum S; Jorde, Lynn B; Kaelin, William G; Koivunen, Peppi; Prchal, Josef T

    2014-09-01

    Tibetans do not exhibit increased hemoglobin concentration at high altitude. We describe a high-frequency missense mutation in the EGLN1 gene, which encodes prolyl hydroxylase 2 (PHD2), that contributes to this adaptive response. We show that a variant in EGLN1, c.[12C>G; 380G>C], contributes functionally to the Tibetan high-altitude phenotype. PHD2 triggers the degradation of hypoxia-inducible factors (HIFs), which mediate many physiological responses to hypoxia, including erythropoiesis. The PHD2 p.[Asp4Glu; Cys127Ser] variant exhibits a lower K(m) value for oxygen, suggesting that it promotes increased HIF degradation under hypoxic conditions. Whereas hypoxia stimulates the proliferation of wild-type erythroid progenitors, the proliferation of progenitors with the c.[12C>G; 380G>C] mutation in EGLN1 is significantly impaired under hypoxic culture conditions. We show that the c.[12C>G; 380G>C] mutation originated ∼8,000 years ago on the same haplotype previously associated with adaptation to high altitude. The c.[12C>G; 380G>C] mutation abrogates hypoxia-induced and HIF-mediated augmentation of erythropoiesis, which provides a molecular mechanism for the observed protection of Tibetans from polycythemia at high altitude.

  20. Mood changes at very high altitudes in Pakistan

    PubMed Central

    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

  1. Use of the Gamow Bag by EMT-basic park rangers for treatment of high-altitude pulmonary edema and high-altitude cerebral edema.

    PubMed

    Freeman, Kimberly; Shalit, Marc; Stroh, Geoffrey

    2004-01-01

    As part of an emergency medical system protocol, national park service rangers certified at the level of an emergency medical technician-basic (EMT-B) are taught to recognize and treat high-altitude pulmonary edema and high-altitude cerebral edema. In Sequoia and Kings Canyon National Parks, this is done with the assistance of physician on-line medical control as a backup. High-altitude pulmonary edema and high-altitude cerebral edema are both potentially fatal altitude illnesses that can be particularly problematic in the backcountry, where evacuation may be delayed. We report a case of high-altitude pulmonary edema and high-altitude cerebral edema occurring at moderate altitude that was successfully treated by park rangers with the Gamow Bag.

  2. Nonequilibrium viscous flow over Jovian entry probes at high altitudes

    NASA Technical Reports Server (NTRS)

    Kumar, A.; Szema, K. Y.; Tiwari, S. N.

    1979-01-01

    The viscous chemical nonequilibrium flow around a Jovian entry body is investigated at high altitudes using two different methods. First method is only for the stagnation region and integrates the full Navier-Stokes equations from the body surface to the freestream. The second method uses viscous shock layer equations between the body surface and the shock. Due to low Reynolds numbers, both methods use surface slip boundary conditions and the second method also uses shock slip boundary conditions. The results of the two methods are compared at the stagnation point. It is found that the entire shock layer is under chemical nonequilibrium at higher altitudes and that the slip boundary conditions are important at these altitudes.

  3. Collisional Effects in Simulations of High Altitude Nuclear Explosions

    NASA Astrophysics Data System (ADS)

    Islam, Tanim

    2013-10-01

    The simulation of the later-time (> 1 second) debris dynamics of a high altitude nuclear explosion (HANE) require, at a minimum, an understanding of the interaction of the ionized blast material with the relatively collisional upper ionosphere and lower exosphere (<= 200 km). At these altitudes, the collisional mean free path of ionized atmospheric particles may become smaller than the length scale of the diamagnetic bubble. Here we report on the local dynamics about the debris/air interface for Starfish Prime like, and lower energy, HANEs at altitudes in which collisionality becomes important. We model the debris dynamics with the hybrid plasma simulation code KIM3D, and use a standard Miller-Combi particle pairing algorithm to model particle collisions. We demonstrate new dynamics associated with finite collisionality in mildly collisional HANEs.

  4. The GRAD high-altitude balloon flight over Antarctica

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

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

  5. 40 CFR 600.310-86 - Labeling of high altitude vehicles.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 30 2011-07-01 2011-07-01 false Labeling of high altitude vehicles... Regulations for 1977 and Later Model Year Automobiles-Labeling § 600.310-86 Labeling of high altitude vehicles... altitude vehicles according to § 600.306. (b) A high altitude vehicle may be labeled with a general...

  6. High-Altitude Electromagnetic Pulse (HEMP) Testing

    DTIC Science & Technology

    2015-07-09

    sky waves. Low frequencies utilize the ground wave path, while the high frequency band utilizes the sky wave path which is reflected back to earth ...magnetic induction, the principal mechanism when the conducting structure forms a closed loop; and earth transfer impedance for buried conductors...response and the inverse FFT results in the corrected time response with the appropriate units. TOP 01-2-620A 9 July 2015 F-2 APPENDIX F

  7. High altitude, prolonged exercise, and the athlete biological passport.

    PubMed

    Schumacher, Yorck O; Garvican, Laura A; Christian, Ryan; Lobigs, Louisa M; Qi, Jiliang; Fan, Rongyun; He, Yingying; Wang, Hailing; Gore, Christopher J; Ma, Fuhai

    2015-01-01

    The Athlete Biological Passport (ABP) detects blood doping in athletes through longitudinal monitoring of erythropoietic markers. Mathematical algorithms are used to define individual reference ranges for these markers for each athlete. It is unclear if altitude and exercise can affect the variables included in these calculations in a way that the changes might be mistaken for blood manipulation. The aim of this study was to investigate the influence of the simultaneous strenuous exercise and low to high altitude exposure on the calculation algorithms of the ABP. 14 sea level (SL) and 11 altitude native (ALT) highly trained athletes participated in a 14-day cycling stage race taking place at an average altitude of 2496 m above sea level (min. 1014 m, max. 4120 m), race distances ranged between 96 and 227 km per day. ABP blood measures were taken on days -1,3,6,10,14 (SL) and -1,9,15 (ALT) of the race. Four results from three samples of two different SL athletes exceeded the individual limits at the 99% specificity threshold and one value at 99.9%. In ALT, three results from three samples of three different athletes were beyond the individual limits at 99%, one at 99.9%. The variations could be explained by the expected physiological reaction to exercise and altitude. In summary, the abnormalities observed in the haematological ABP´s of well-trained athletes during extensive exercise at altitude are limited and in line with expected physiological changes.

  8. High Altitude Platform Aircraft at NASA Past, Present and Future

    NASA Technical Reports Server (NTRS)

    DelFrate, John H.

    2006-01-01

    This viewgraph presentation reviews NASA Dryden Flight Research Center's significant accomplishments from the Environment Research and Sensor Technology (ERAST) project, the present High Altitude Platform (HAP) needs and opportunities, NASA's Aeronautical focus shift, HAP Non-aeronautics challenges, and current HAP Capabilities.

  9. Chicxulub High-Altitude Ballistic Ejecta from Central Belize

    NASA Technical Reports Server (NTRS)

    Pope, K. O.; Ocampo, A. C.

    2000-01-01

    Chicxulub ejecta are found in central Belize, 475 km southeast of the impact crater center. These deposits are ballistic ejecta launched along high-altitude trajectories above the atmosphere and deposited as a discontinuous sheet on the terminal Cretaceous land surface.

  10. [Newest research progress in hypoxia genetic adaptation to high altitude].

    PubMed

    Zhou, Futao; Sun, Xuechuan

    2010-06-01

    The genetic adaptation of Plateau residents to hypoxia of low-pressure has been the hot spot for study. In terms of physiology, the adaptation involves the regulation responses of blood vessels, the changes in blood cells, antioxidant capacity and energy metabolism, as well as the hypoxia-induced changes in nuclear transcription. Physiological adaptation is heritable, so people who have already adapted themselves to high altitude are bound to be different, in regard to gene level, from the crowd who have not yet adapted themselves to high altitude environment. For this reason, researchers have studied a great deal of gene related-enzymes, the receptors, polypeptide, as well as transcription factors in body, and they found a number of the DNA polymorphism sites in the people who have adapted themsevles to high altitude being different from those in the people who do not get acclimatized. In this paper is reviewed the newest advance in research of these gene polymorphisms. The data could serve as references for further study of hypoxia genetic adaptation to high altitude.

  11. Respiratory gas exchange of high altitude adapted chick embryos

    NASA Technical Reports Server (NTRS)

    Wangensteen, O. D.; Rahn, H.; Burton, R. R.; Smith, A. H.

    1974-01-01

    Study of gas exchange by embryos from chickens acclimatized to an altitude of 3800 m. The oxygen partial pressure and carbon dioxide partial pressure differences across the egg shell were measured and found to be less than the values previously reported for sea-level eggs by about a factor of two. Further measurements of embryonic oxygen consumption and shell conductivity to oxygen indicated that, compared to eggs at sea level, oxygen consumption was reduced by a factor of 0.58 while conductivity to oxygen was increased only by a factor of 1.07 in the high-altitude eggs. These independent measurements predict the change in oxygen partial pressure across the egg shell of the high-altitude eggs to be only 0.54 times that of sea-level eggs; the directly measured factor was 0.53. The authors conclude that at high altitude, a major adaptation of the chick embryo is a reduced metabolism which decreases the change in oxygen partial pressure across the egg shell since its gas conductivity remains essentially unchanged.

  12. Common High Altitudes Illnesses a Primer for Healthcare Provider

    PubMed Central

    Mohsenin, Vahid

    2015-01-01

    Exposure to high altitude imposes significant strain on cardiopulmonary system and the brain. As a consequence, sojourners to high altitude frequently experience sleep disturbances, often reporting restless and sleepless nights. At altitudes above 3,000 meters (9,800 ft) almost all healthy subjects develop periodic breathing especially during NREM sleep. Sleep architecture gradually improves with increased NREM and REM sleep despite persistence of periodic breathing. The primary reason for periodic breathing at high altitude is a hypoxic-induced increase in chemoreceptor sensitivity to changes in PaCO2 – both above and below eupnea, leading to periods of apnea and hyperpnea. Acetazolamide improves sleep by reducing the periodic breathing through development of metabolic acidosis and induced hyperventilation decreasing the plant gain and widening the PCO2 reserve. This widening of the PCO2 reserve impedes development of central apneas during sleep. Benzodiazepines and GABA receptor antagonist such as zolpidem improve sleep without affecting breathing pattern or cognitive functions. PMID:27057512

  13. Theodor Benzinger, German pioneer in high altitude physiology research and altitude protection.

    PubMed

    Harsch, Viktor

    2007-09-01

    Theodore Benzinger was a pilot-physician who performed pioneering research-often involving self-experimentation-in areas related to flight at high altitude during World War II. Of greatest historical interest to those of us in aerospace medicine is his work on the effects of rapid decompression and related oxygen equipment. Benzinger was born in Stuttgart, Germany, on 28th August 1905. He studied medicine and natural sciences at the universities of Tuebingen, Munich, and Berlin. From 1934 to 1944, Benzinger headed the aeromedical laboratory "EMed" in Rechlin, where he was instrumental in conducting studies related to stratospheric flight, including self-experimentation with rapid decompression up to 19,000 m (62,320 ft). His Rechlin experiments made an important contribution to understanding the physiology and life-support requirements for high-altitude aviation and later work under space-equivalent conditions. Following World War II, Benzinger joined the staff of the U.S. Army Air Force Aeromedical Center in Heidelberg. In 1947 he was recruited by "Operation Paperclip" to work at the U.S. Naval Medical Research Institute (NMRI) in Bethesda, MD, where he worked on various aspects of human physiology. He died as a U.S. citizen in Bethesda, MD, on 26th October 1999.

  14. High Altitude Plasma Instrument (HAPI) data analysis. Final report

    SciTech Connect

    Burch, J.L.

    1994-01-01

    The objectives of the Dynamics Explorer mission are to investigate the coupling of energy, mass, and momentum among the earth's magnetosphere, ionosphere, and upper atmosphere. At launch, on August 3, 1981, DE-1 was placed into an elliptical polar orbit having an apogee of 23,130 km to allow global auroral imaging and crossings of auroral field lines at altitudes of several thousand kilometers. At the same time DE-2 was placed into a polar orbit, coplanar with that of DE-1 but with a perigee altitude low enough (309 km) for neutral measurements and an apogee altitude of 1012 km. The DE-1 High Altitude Plasma Instrument (HAPI) provided data on low and medium energy electrons and ions from August 13, 1981 until December 1, 1981, when a high-voltage failure occured. Analysis of HAPI data for the time period of this contract has produced new results on the source mechanisms for electron conical distributions, particle acceleration phenomena in auroral acceleration regions, Birkeland currents throughout the nightside auroral regions, the source region for auroral kilometric radiation (AKR), and plasma injection phenomena in the polar cusp.

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

    PubMed

    Brutsaert, Tom

    2016-01-01

    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.

  16. An oxygen enrichment device for lowlanders ascending to high altitude

    PubMed Central

    2013-01-01

    Background When ascending to the high altitude, people living in low altitude areas will suffer from acute mountain sickness. The aim of this study is to test the hypothesis that whether an oxygen concentration membrane can be made and used to construct a new portable oxygen enrichment device for individuals in acute exposure to the high altitude. Methods The membrane was fabricated using vinylsiloxane rubber, polyphenylene oxide hydrogen silicone polymers, chloroplatinic acid and isopropyl alcohol. The membrane was assembled in a frame and the performance was tested in terms of concentration of oxygen, flow rate of oxygen enriched air, pressure ratio across the membrane and ambient temperature. Furthermore, the oxygen concentration device was constructed using the membrane, a DC fan, vacuum pump and gas buffer. A nonrandomized preliminary field test was conducted, in which eight healthy male subjects were flown to Tibet (Lhasa, 3,700 m). First, subjects wore the oxygen enrichment device and performed an incremental exercise on cycle ergometer. The test included heart rate (HR), saturation of peripheral oxygen (SpO2) and physical work capacity (PWC). Then, after a rest period of 4 hours, the experimental protocol was repeated without oxygen enrichment device. Results The testing showed that the membrane could increase the oxygen concentration by up to 30%. Simulation test indicated that although the performance of the oxygen enrichment device decreased with altitudes, the oxygen concentration could still maintain 28% with flow rate of enriched air 110 cm3/s at 5000 m. The field test showed that higher SpO2, lower HR, and better PWC (measured by the PWC-170) were observed from all the subjects using oxygen enrichment device compared with non-using (P < 0.01). Conclusions We concluded that the new portable oxygen enrichment device would be effective in improving exercise performance when ascending to the high altitude. PMID:24103365

  17. Whole-genome sequencing of six dog breeds from continuous altitudes reveals adaptation to high-altitude hypoxia

    PubMed Central

    Gou, Xiao; Wang, Zhen; Li, Ning; Qiu, Feng; Xu, Ze; Yan, Dawei; Yang, Shuli; Jia, Jia; Kong, Xiaoyan; Wei, Zehui; Lu, Shaoxiong; Lian, Linsheng; Wu, Changxin; Wang, Xueyan; Li, Guozhi; Ma, Teng; Jiang, Qiang; Zhao, Xue; Yang, Jiaqiang; Liu, Baohong; Wei, Dongkai; Li, Hong; Yang, Jianfa; Yan, Yulin; Zhao, Guiying; Dong, Xinxing; Li, Mingli; Deng, Weidong; Leng, Jing; Wei, Chaochun; Wang, Chuan; Mao, Huaming; Zhang, Hao; Ding, Guohui; Li, Yixue

    2014-01-01

    The hypoxic environment imposes severe selective pressure on species living at high altitude. To understand the genetic bases of adaptation to high altitude in dogs, we performed whole-genome sequencing of 60 dogs including five breeds living at continuous altitudes along the Tibetan Plateau from 800 to 5100 m as well as one European breed. More than 150× sequencing coverage for each breed provides us with a comprehensive assessment of the genetic polymorphisms of the dogs, including Tibetan Mastiffs. Comparison of the breeds from different altitudes reveals strong signals of population differentiation at the locus of hypoxia-related genes including endothelial Per-Arnt-Sim (PAS) domain protein 1 (EPAS1) and beta hemoglobin cluster. Notably, four novel nonsynonymous mutations specific to high-altitude dogs are identified at EPAS1, one of which occurred at a quite conserved site in the PAS domain. The association testing between EPAS1 genotypes and blood-related phenotypes on additional high-altitude dogs reveals that the homozygous mutation is associated with decreased blood flow resistance, which may help to improve hemorheologic fitness. Interestingly, EPAS1 was also identified as a selective target in Tibetan highlanders, though no amino acid changes were found. Thus, our results not only indicate parallel evolution of humans and dogs in adaptation to high-altitude hypoxia, but also provide a new opportunity to study the role of EPAS1 in the adaptive processes. PMID:24721644

  18. Lockheed ER-2 #806 high altitude research aircraft in flight

    NASA Technical Reports Server (NTRS)

    1998-01-01

    ER-2 tail number 806, is one of two Airborne Science ER-2s used as science platforms by Dryden. The aircraft are platforms for a variety of high-altitude science missions flown over various parts of the world. They are also used for earth science and atmospheric sensor research and development, satellite calibration and data validation. The ER-2s are capable of carrying a maximum payload of 2,600 pounds of experiments in a nose bay, the main equipment bay behind the cockpit, two wing-mounted superpods and small underbody and trailing edges. Most ER-2 missions last about six hours with ranges of about 2,200 nautical miles. The aircraft typically fly at altitudes above 65,000 feet. On November 19, 1998, the ER-2 set a world record for medium weight aircraft reaching an altitude of 68,700 feet. The aircraft is 63 feet long, with a wingspan of 104 feet. The top of the vertical tail is 16 feet above ground when the aircraft is on the bicycle-type landing gear. Cruising speeds are 410 knots, or 467 miles per hour, at altitude. A single General Electric F-118 turbofan engine rated at 17,000 pounds thrust powers the ER-2.

  19. Lockheed ER-2 high altitude research aircraft in flight

    NASA Technical Reports Server (NTRS)

    1997-01-01

    ER-2 tail number 706, is one of two Airborne Science ER-2s used as science platforms by Dryden. The aircraft are platforms for a variety of high-altitude science missions flown over various parts of the world. They are also used for earth science and atmospheric sensor research and development, satellite calibration and data validation. The ER-2s are capable of carrying a maximum payload of 2,600 pounds of experiments in a nose bay, the main equipment bay behind the cockpit, two wing-mounted superpods and small underbody and trailing edges. Most ER-2 missions last about six hours with ranges of about 2,200 nautical miles. The aircraft typically fly at altitudes above 65,000 feet. On November 19, 1998, the ER-2 set a world record for medium weight aircraft reaching an altitude of 68,700 feet. The aircraft is 63 feet long, with a wingspan of 104 feet. The top of the vertical tail is 16 feet above ground when the aircraft is on the bicycle-type landing gear. Cruising speeds are 410 knots, or 467 miles per hour, at altitude. A single General Electric F-118 turbofan engine rated at 17,000 pounds thrust powers the ER-2.

  20. Lockheed ER-2 #806 high altitude research aircraft during landing

    NASA Technical Reports Server (NTRS)

    1998-01-01

    ER-2 tail number 806, is one of two Airborne Science ER-2s used as science platforms by Dryden. The aircraft are platforms for a variety of high-altitude science missions flown over various parts of the world. They are also used for earth science and atmospheric sensor research and development, satellite calibration and data validation. The ER-2s are capable of carrying a maximum payload of 2,600 pounds of experiments in a nose bay, the main equipment bay behind the cockpit, two wing-mounted superpods and small underbody and trailing edges. Most ER-2 missions last about six hours with ranges of about 2,200 nautical miles. The aircraft typically fly at altitudes above 65,000 feet. On November 19, 1998, the ER-2 set a world record for medium weight aircraft reaching an altitude of 68,700 feet. The aircraft is 63 feet long, with a wingspan of 104 feet. The top of the vertical tail is 16 feet above ground when the aircraft is on the bicycle-type landing gear. Cruising speeds are 410 knots, or 467 miles per hour, at altitude. A single General Electric F-118 turbofan engine rated at 17,000 pounds thrust powers the ER-2.

  1. Lockheed ER-2 #809 high altitude research aircraft in flight

    NASA Technical Reports Server (NTRS)

    1999-01-01

    ER-2 tail number 809, is one of two Airborne Science ER-2s used as science platforms by Dryden. The aircraft are platforms for a variety of high-altitude science missions flown over various parts of the world. They are also used for earth science and atmospheric sensor research and development, satellite calibration and data validation. The ER-2s are capable of carrying a maximum payload of 2,600 pounds of experiments in a nose bay, the main equipment bay behind the cockpit, two wing-mounted superpods and small underbody and trailing edges. Most ER-2 missions last about six hours with ranges of about 2,200 nautical miles. The aircraft typically fly at altitudes above 65,000 feet. On November 19, 1998, the ER-2 set a world record for medium weight aircraft reaching an altitude of 68,700 feet. The aircraft is 63 feet long, with a wingspan of 104 feet. The top of the vertical tail is 16 feet above ground when the aircraft is on the bicycle-type landing gear. Cruising speeds are 410 knots, or 467 miles per hour, at altitude. A single General Electric F118 turbofan engine rated at 17,000 pounds thrust powers the ER-2.

  2. Lockheed ER-2 #809 high altitude research aircraft in flight

    NASA Technical Reports Server (NTRS)

    1998-01-01

    ER-2 tail number 809, is one of two Airborne Science ER-2s used as science platforms by Dryden. The aircraft are platforms for a variety of high-altitude science missions flown over various parts of the world. They are also used for earth science and atmospheric sensor research and development, satellite calibration and data validation. The ER-2s are capable of carrying a maximum payload of 2,600 pounds of experiments in a nose bay, the main equipment bay behind the cockpit, two wing-mounted superpods and small underbody and trailing edges. Most ER-2 missions last about six hours with ranges of about 2,200 nautical miles. The aircraft typically fly at altitudes above 65,000 feet. On November 19, 1998, the ER-2 set a world record for medium weight aircraft reaching an altitude of 68,700 feet. The aircraft is 63 feet long, with a wingspan of 104 feet. The top of the vertical tail is 16 feet above ground when the aircraft is on the bicycle-type landing gear. Cruising speeds are 410 knots, or 467 miles per hour, at altitude. A single General Electric F-118 turbofan engine rated at 17,000 pounds thrust powers the ER-2.

  3. High altitude solar power platform. [aircraft design analysis

    NASA Technical Reports Server (NTRS)

    Bailey, M. D.; Bower, M. V.

    1992-01-01

    Solar power is a preeminent alternative to conventional aircraft propulsion. With the continued advances in solar cells, fuel cells, and composite materials technology, the solar powered airplane is no longer a simple curiosity constrained to flights of several feet in altitude or minutes of duration. A high altitude solar powered platform (HASPP) has several potential missions, including communications and agriculture. In remote areas, a HASPP could be used as a communication link. In large farming areas, a HASPP could perform remote sensing of crops. The impact of HASPP in continuous flight for one year on agricultural monitoring mission is presented. This mission provides farmers with near real-time data twice daily from an altitude which allows excellant resolution on water conditions, crop diseases, and insect infestation. Accurate, timely data will enable farmers to increase their yield and efficiency. A design for HASPP for the foregoing mission is presented. In the design power derived from solar cells covering the wings is used for propulsion, avionics, and sensors. Excess power produced midday will be stored in fuel cells for use at night to maintain altitude and course.

  4. High-Altitude Cassini Radar Imaging of Titan

    NASA Astrophysics Data System (ADS)

    West, R. D.; Stiles, B.; Anderson, Y.; Boehmer, R.; Callahan, P.; Gim, Y.; Hamilton, G.; Hensley, S.; Janssen, M.; Johnson, W. T.; Kelleher, K.; Lorenz, R.; Ostro, S.; Paganelli, F.; Shaffer, S.; Wye, L.; Zebker, H.

    2006-12-01

    The Cassini spacecraft is now about halfway through its primary Tour of the Saturn system. By the time of this meeting, the radar instrument will have collected seven synthetic aperture strips during close flyby's, with 13 more to come. These images have resolutions as fine as 300 m. We present here data acquired using another imaging mode, very high altitude synthetic aperture radar (SAR) imaging, which extends imaging radar coverage and increases coincidental coverage with other Cassini imaging instruments such as VIMS and ISS. We also discuss calibration of SAR images and other radar data from additional engineering observations. Here we examine the performance trade-offs, special processing issues, and science potential of the high- altitude image observations, and the latest results from the calibration data. The high-altitude data collections are distinct from the normal Titan radar images because the range is much larger (around 20,000 km vs 950 km to 5000 km for normal SAR passes). To increase the signal to noise ratio in these circumstances, the radar operates in the lowest bandwidth scatterometer mode while spacecraft pointing control is used to slowly pan the central beam across a small swath. These high altitude images incorporate 150-200 independent looks in order to let us discriminate features that may lie below the noise floor. So far, three high-altitude images have been acquired, during Titan flyby's T12, T13, and T15. In T12 imaging was attempted from 37000 km with an effective resolution around 5 km. In T13 the Huygens Probe landing site was imaged from 11000 km with effective resolution of 1 2 km. In T15 the Tsegehi area was imaged from 20000 km with effective resolution of 2 -3 km. Additional high altitude image segments are also planned during the T19 and T20 Titan flyby's. The calibration observations are conducted independently or coupled with a distant icy satellite observation. They consist of receive-only data in all four bandwidths

  5. The University of Alberta High Altitude Balloon Program

    NASA Astrophysics Data System (ADS)

    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.

  6. Endogenous Asymmetric Dimethylarginine Pathway in High Altitude Adapted Yaks

    PubMed Central

    Mizuno, Shiro; Ishizaki, Takeshi; Toga, Hirohisa; Sakai, Akio; Isakova, Jainagul; Taalaibekova, Elnura; Baiserkeev, Zamirbek; Kojonazarov, Baktybek; Aldashev, Almaz

    2015-01-01

    Hypoxia-induced and high altitude pulmonary hypertension are a major problem in the mountain areas of the world. The asymmetric methylarginines (ADMA) inhibit nitric oxide (NO) synthesis by competing with L-arginine, and high levels of plasma ADMA predict adverse outcomes in pulmonary hypertension. However, little is known about the regulation of the ADMA-NO pathway in animals adapted to high altitudes. We measured the plasma ADMA concentration, endothelial NO synthase (eNOS), dimethylarginine dimethylaminohydrolases (DDAH) protein expression, and DDAH activities in the lungs from yaks. Although the yaks are hypoxemic, cardiac function and pulmonary arterial pressures are almost normal, and we found decreased DDAH expression and activity in association with reduced plasma ADMA concentrations. The eNOS expression was significantly higher in yaks. These results indicate that augmented endogenous NO activity in yaks through the ADMA-DDAH pathway and eNOS upregulation account for the low pulmonary vascular tone observed in high altitude adapted yaks. PMID:26380264

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

    PubMed

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

    2014-05-01

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

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

    NASA Astrophysics Data System (ADS)

    Carramiñana, Alberto

    2016-10-01

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

  9. THe high altitude reconnaissance platform (HARP) and its capabilities

    SciTech Connect

    Rusk, D.; Rose, R.L.; Gibeau, E.

    1996-10-01

    The High Altitude Reconnaissance Platform (HARP), a Learjet 36A, is a multi-purpose, long-range, high-altitude aircraft specially modified to serve as a meteorological observation platform. Its instrument suite includes: particle probes, Ka-band radar, two-color lidar, infrared spectroradiometer, thermometer, hygrometer, liquid water probe, and a gust probe. Aeromet scientists have developed software and hardware systems that combine data using sensor fusion concepts, providing detailed environmental information. The HARP answers the need for defining and predicting meteorological conditions throughout large atmospheric volumes particularly in areas where conventional surface and upper-air observations are not available. It also fills the need for gathering and predicting meteorological conditions along an optical sensor`s line of sight or a missile`s reentry path. 6 refs., 2 figs., 4 tabs.

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

    NASA Technical Reports Server (NTRS)

    Colozza, Anthony; Dolce, James (Technical Monitor)

    2003-01-01

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

  11. Platelet count on slow induction to high altitude

    NASA Astrophysics Data System (ADS)

    Sharma, Subhash C.

    1986-03-01

    Platelet counts were estimated at sea level in 50 lowlanders. They were divided at random in two groups (A and B) of 25 each. Group A went up by train/road transport to 3658 m, while group B reached the same height after 8 days of acclimatisation enroute. Platelet counts were estimated serially in both groups at high altitude. Symptoms of high altitude exposure were also recorded. No significant change in the counts was noted in either group and none became “Symptomatic”. All were brought back to sea level by air and deinduction studies carried out on days 1 and 4 of return. The importance of these findings in the light of our existing knowledge is discussed.

  12. NEW HORIZONS FOR THE NATIONAL HIGH-ALTITUDE PHOTOGRAPHY PROGRAM.

    USGS Publications Warehouse

    Bermel, Peter F.

    1983-01-01

    The National High-Altitude Photography Program (NHAP) is a multi-Federal agency activity to acquire uniform imagery for the establishment of a national high-altitude photographic data base. Since the inception of NHAP in 1980, black-and-white and color infrared stereoscopic imagery has been acquired for about 50% of the 3,000,000 square miles in the conterminous United States. An additional 40% of the 48-State area is under contract to private aerial survey firms, and the sixth and final contract to achieve complete once-over coverage will be awarded early in 1985. Extensive use has been made of the newly established data base. The participating agencies have begun studies to define the requirements for a maintenance program which would provide cyclic coverage of the conterminous United States and imagery for specific agency needs.

  13. Nifedipine for Treatment of High Altitude Pulmonary Edema.

    DTIC Science & Technology

    1992-07-30

    cohsistent effect on spirometry. In addition, we undertook a survey of pulmonary hypertension (PHT) at high altitude, and surprisingly discovered excessive...Systems model #503), auscultation of all lung fields, and systemic blood pressure both supine and standing. Forced vital capacity, peak expiratory flow...the same chew and swallow manner. The protocol called for repeat dosing every thirty minutes, depending upon the blood pressure response of the

  14. Disease Threat at High Terrestrial Altitudes. Volume 1.

    DTIC Science & Technology

    1979-08-01

    trichiura, 65.%-- Ascaris lumbricoides , 32.5%; Hymenolepis nana, 3.8%; Taenia spp., 1.6%; Strongyloides stercoralis, 1.2%; and hookworm--(g-enus/genera not...within an area. Thus, vegetation patterns characteristic of different mountain ranges and, in fact, between peaks within a range, are the result of... characteristics of the high altitude areas of the world. The upper altitudinal limit of the forest varies greatlv and is influenced by a number of factors

  15. Blood-Brain Barrier Changes in High Altitude.

    PubMed

    Lafuente, José V; Bermudez, Garazi; Camargo-Arce, Lorena; Bulnes, Susana

    2016-01-01

    Cerebral syndromes related to high-altitude exposure are becoming more frequent as the number of trips to high altitudes has increased in the last decade. The commonest symptom is headache, followed by acute mountain sickness (AMS) and high-altitude cerebral edema (HACE), which can be fatal. The pathophysiology of these syndromes is not fully understood. The classical "tight-fit hypothesis" posits that there are some anatomical variations that would obstruct the sinovenous outflow and worsen vasogenic edema and intracranial hypertension reactive to hypoxia. This could explain microhemorrhages seen in autopsies. However, recent magnetic resonance imaging studies have demonstrated some components of cytotoxic edema in HACE absent in AMS, suggesting a dysfunction in water balance at the cellular level. Currently, the "red-ox theory" supports trigemino-vascular system activation by free radicals formed after hypoxia and the consequent oxidative stress cascades. Apart from trigemino-vascular system activation, free radicals can also provoke membrane destabilisation mediated by lipid peroxidation, inflammation, and local hypoxia inducible factor-1α and vascular endothelial growth factor activation, resulting in gross blood-brain barrier (BBB) dysfunction. Besides alterations in endothelial cells such as increased pinocytotic vesicles and disassembly of interendothelial tight junction proteins, capillary permeability may also increase with subsequent swelling of astrocyte end-feet. In conclusion, although the pathophysiology of AMS and HACE is not completely understood, recent evidence proposes a multifactorial entity, with brain swelling and compromise of the BBB considered to play an important role. A fuller comprehension of these processes is crucial to reduce and prevent BBB alterations during high-altitude exposure.

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

    SciTech Connect

    Zhang, Yuhuai; Wan, Tian; Jiang, Jianzheng; Fan, Jing

    2014-12-09

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

  17. 'Ome' on the range: update on high-altitude acclimatization/adaptation and disease.

    PubMed

    Luo, Yongjun; Wang, Yuxiao; Lu, Hongxiang; Gao, Yuqi

    2014-11-01

    The main physiological challenge in high-altitude plateau environments is hypoxia. When people living in a plain environment migrate to the plateau, they face the threat of hypoxia. Most people can acclimatize to high altitudes; the acclimatization process mainly consists of short-term hyperventilation and long-term compensation by increased oxygen uptake, transport, and use due to increased red blood cell mass, myoglobin, and mitochondria. If individuals cannot acclimatize to high altitude, they may suffer from a high-altitude disease, such as acute mountain disease (AMS), high-altitude pulmonary edema (HAPE), high-altitude cerebral edema (HACE) or chronic mountain sickness (CMS). Because some individuals are more susceptible to high altitude diseases than others, the incidence of these high-altitude diseases is variable and cannot be predicted. Studying "omes" using genomics, proteomics, metabolomics, transcriptomics, lipidomics, immunomics, glycomics and RNomics can help us understand the factors that mediate susceptibility to high altitude illnesses. Moreover, analysis of the "omes" using a systems biology approach may provide a greater understanding of high-altitude illness pathogenesis and improve the efficiency of the diagnosis and treatment of high-altitude illnesses in the future. Below, we summarize the current literature regarding the role of "omes" in high-altitude acclimatization/adaptation and disease and discuss key research gaps to better understand the contribution of "omes" to high-altitude illness susceptibility.

  18. Mechanism of reduced cardiac stroke volume at high altitude.

    PubMed

    Alexander, J K; Grover, R F

    1983-06-01

    Two postulates have been advanced to account for reduced stroke at high altitude: (1) diminished venous return secondary to contracted plasma volume and (2) left ventricular (LV) dysfunction secondary to hypoxia. To test these hypotheses, we assessed LV dimensions and contractility indices by M-mode echocardiography and systolic time intervals in 11 young men at sealevel and serially for 10 days at 3100 m altitude. Mean LV end-diastolic dimension fell 16% after 6-8 days, with a 20% decrease in plasma volume reflected by hematocrit rise. Pre-ejection period to LV ejection time (PEP/LVET) ratio was increased after 1-2 days. All indices of contractility were unchanged at rest, and slightly enhanced during exercise. Thus stroke volume falls and PEP/LVET ratio rises at 3100 m because of diminished venous return despite preservation of LV systolic performance.

  19. Applications of a high-altitude powered platform /HAPP/

    NASA Technical Reports Server (NTRS)

    Kuhner, M. B.

    1979-01-01

    The high-altitude powered platform (HAPP) is a conceptual unmanned vehicle which could be either an airship or airplane. It would keep station at an altitude of 70,000 ft above a fixed point on the ground. A microwave power transmission system would beam energy from the ground up to the HAPP to power an electric motor-driven propeller and the payload. A study of the HAPP has shown that it could potentially be a cost-competitive platform for such remote sensing applications as forest fire detection, Great Lakes ice monitoring and Coast Guard law enforcement. It also has significant potential as a communications relay platform for (among other things) direct broadcast to home TVs over a large region.

  20. Cardiac and vascular disease prior to hatching in chick embryos incubated at high altitude.

    PubMed

    Salinas, C E; Blanco, C E; Villena, M; Camm, E J; Tuckett, J D; Weerakkody, R A; Kane, A D; Shelley, A M; Wooding, F B P; Quy, M; Giussani, D A

    2010-02-01

    The partial contributions of reductions in fetal nutrition and oxygenation to slow fetal growth and a developmental origin of cardiovascular disease remain unclear. By combining high altitude with the chick embryo model, we have previously isolated the direct effects of high-altitude hypoxia on growth. This study isolated the direct effects of high-altitude hypoxia on cardiovascular development. Fertilized eggs from sea-level or high-altitude hens were incubated at sea level or high altitude. Fertilized eggs from sea-level hens were also incubated at high altitude with oxygen supplementation. High altitude promoted embryonic growth restriction, cardiomegaly and aortic wall thickening, effects which could be prevented by incubating eggs from high-altitude hens at sea level or by incubating eggs from sea-level hens at high altitude with oxygen supplementation. Embryos from high-altitude hens showed reduced effects of altitude incubation on growth restriction but not on cardiovascular remodeling. The data show that: (1) high-altitude hypoxia promotes embryonic cardiac and vascular disease already evident prior to hatching and that this is associated with growth restriction; (2) the effects can be prevented by increased oxygenation; and (3) the effects are different in embryos from sea-level or high-altitude hens.

  1. Physical fitness of children resident at high altitude in Bolivia.

    PubMed

    Fellmann, N; Coudert, J; Spielvogel, H; Bedu, M; Obert, P; Falgairette, G; Van Praagh, E

    1992-10-01

    In 7-15-yr-old children living in La Paz (Bolivia, altitude 3,700 m) (HA): 1) Maximal oxygen consumption (VO2max) varies from 35 to 45 ml.min-1.kg-1 and maximal heart rate from 188 to 194 beats.min-1. These values are lower than those of their counterparts at low altitude (LA) by 10-20% and 10-15 b.min-1, respectively. 2) The anaerobic metabolism is not affected by chronic hypoxia if the nutritional conditions and pubertal development of HA and LA boys are the same. When related to percent of VO2max, submaximal O2 debts are similar at HA and LA. After supramaximal exercise, maximal O2 debts (45.7 +/- 2.7 vs 45.9 +/- 3.8 ml.kg-1) and blood lactate concentrations (7.6 +/- 0.6 vs 6.5 +/- 0.6 mmol.l-1) are also the same at HA and LA. No differences are observed between the 2 altitudes in ventilatory (60 vs 56% VO2max) and lactate (60 vs 65% VO2max) thresholds. The altitude of La Paz does not alter the anaerobic performance of a force-velocity test (from 6 to 10 W.kg-1) between the ages of 7 to 15 years but reduces by 14-17% the mean anaerobic power developed during a 30-s Wingate test. This decrease could be linked to a lower participation of glycolysis and aerobic metabolism at HA during this test. 3) Poor socio-economic and nutritional conditions do not modify the aerobic performance of boys living in La Paz but lead to lower maximal anaerobic power (from -17% to -25%) when compared with HA boys from a high socio-economic background.(ABSTRACT TRUNCATED AT 250 WORDS)

  2. Long-Term Exposure to High Altitude Affects Response Inhibition in the Conflict-monitoring Stage.

    PubMed

    Ma, Hailin; Wang, Yan; Wu, Jianhui; Luo, Ping; Han, Buxin

    2015-09-01

    To investigate the effects of high-altitude exposure on response inhibition, event-related potential (ERP) components N2 and P3 were measured in Go/NoGo task. The participants included an 'immigrant' high-altitude group (who had lived at high altitude for three years but born at low altitude) and a low-altitude group (living in low altitude only). Although the behavioural data showed no significant differences between the two groups, a delayed latency of NoGo-N2 was found in the high-altitude group compared to the low-altitude group. Moreover, larger N2 and smaller P3 amplitudes were found in the high-altitude group compared to the low-altitude group, for both the Go and NoGo conditions. These findings suggest that high-altitude exposure affects response inhibition with regard to processing speed during the conflict monitoring stage. In addition, high altitude generally increases the neural activity in the matching step of information processing and attentional resources. These results may provide some insights into the neurocognitive basis of the effects on high-altitude exposure on response inhibition.

  3. High altitude smoke in the NASA GISS GCM

    NASA Technical Reports Server (NTRS)

    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

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

    NASA Technical Reports Server (NTRS)

    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.

  5. First scientific contributions from the High Altitude Water Cherenkov Observatory

    NASA Astrophysics Data System (ADS)

    León Vargas, H.; HAWC Collaboration

    2015-09-01

    The High Altitude Water Cherenkov Observatory (HAWC), located at the slopes of the volcanoes Sierra Negra and Pico de Orizaba in Mexico, was inaugurated on March 20, 2015. However, data taking started in August 2013 with a partially deployed observatory and since then the instrument has collected data as it got closer to its final configuration. HAWC is a ground based TeV gamma-ray observatory with a large field of view that will be used to study the Northern sky with high sensitivity. In this contribution we present some of the results obtained with the partially built instrument and the expected capabilities to detect different phenomena with the complete observatory.

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

    NASA Astrophysics Data System (ADS)

    Jerde, E. A.; Thomas, E.

    2010-12-01

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

  7. Mitogenomic analyses propose positive selection in mitochondrial genes for high-altitude adaptation in galliform birds.

    PubMed

    Zhou, Taicheng; Shen, Xuejuan; Irwin, David M; Shen, Yongyi; Zhang, Yaping

    2014-09-01

    Galliform birds inhabit very diverse habitats, including plateaus that are above 3000 m in altitude. At high altitude, lower temperature and hypoxia are two important factors influencing survival. Mitochondria, as the ultimate oxygen transductor, play an important role in aerobic respiration through oxidative phosphorylation (OXPHOS). We analyzed the mitochondrial genomes of six high-altitude phasianidae birds and sixteen low-altitude relatives in an attempt to determine the role of mitochondrial genes in high-altitude adaptation. We reconstructed the phylogenetic relationships of these phasianidae birds and relatives and found at least four lineages that independently occupied this high-altitude habitat. Selective analyses revealed significant evidence for positive selection in the genes ND2, ND4, and ATP6 in three of the high-altitude lineages. This result strongly suggests that adaptive evolution of mitochondrial genes played a critical role during the independent acclimatization to high altitude by galliform birds.

  8. Compositae Plants Differed in Leaf Cuticular Waxes between High and Low Altitudes.

    PubMed

    Guo, Na; Gao, Jianhua; He, Yuji; Guo, Yanjun

    2016-06-01

    We sampled eight Compositae species at high altitude (3482 m) and seven species at low altitude (220 m), analyzed the chemical compositions and contents of leaf cuticular wax, and calculated the values of average chain length (ACL), carbon preference index (CPI), dispersion (d), dispersion/weighted mean chain length (d/N), and C31 /(C31  + C29 ) (Norm31). The amounts of total wax and compositions were significantly higher at high altitude than at low altitude, except for primary alcohol, secondary alcohol, and ketone. The main n-alkanes in most samples were C31 , C29 , and C33 . Low altitude had more C31 and C33 , whereas more C29 occurred at high altitude. The ACL, CPI, d, d/N, and Norma 31 were higher at low altitude than at high altitude. The fatty acid and primary alcohol at low altitude contained more C26 homologous than at high altitude. More short-chain primary alcohols were observed at high altitude. At low altitude, the primary alcohol gave on average the largest amount, while it was n-alkane at high altitude. These results indicated that the variations of leaf cuticular waxes benefited Compositae plants to adapt to various environmental stresses and enlarge their distribution.

  9. Stratochip, a dual balloon high-altitude platform: controlled altitude flight experiments and potential applications in geosciences.

    NASA Astrophysics Data System (ADS)

    Burlet, Christian; Vanbrabant, Yves

    2014-05-01

    A high-altitude dual balloons system, the 'Stratochip', was designed at the Geological Survey of Belgium to serve as a development platform to carry measurement and earth observation equipments, in altitudes comprised between 1000 and 25000m. These working altitudes far exceed the range of current motor powered unmanned aerial vehicules, with a higher weight carrying capacity (up to 10-15kg). This platform is built around a two helium balloons configuration, than can be released one by one at a target altitude or location, allowing a partially controlled drift of the platform. Using a 'nowcasting' meteorological model, updated by flight telemetry, the predicted path can be refined live to follow and retrieve the equipment in a predicted landing area. All subsystems (balloon cut-off devices, flight controller, telemetry system) have been developed in-house. Three independent communication channels, designed to work at extremely low temperature (up to -60° C) ensure a continuous tracking until landing. A calibrated parachute is used to control the safe descent of the equipment. Several flight tests have been performed in Belgium to control the meteorological model accuracy for wind predictions (model based on National Oceanic and Atmospheric Administration data). Those tests demonstrated the capability of the platform to maintain its altitude in a predicted path, allowing using the platform for new types of atmospheric studies and affordable high-altitude remote-sensing applications (i.e. sub-meter resolution stereo imagery).

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

    NASA Technical Reports Server (NTRS)

    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. An Undergraduate-Built Prototype Altitude Determination System (PADS) for High Altitude Research Balloons.

    NASA Astrophysics Data System (ADS)

    Verner, E.; Bruhweiler, F. C.; Abot, J.; Casarotto, V.; Dichoso, J.; Doody, E.; Esteves, F.; Morsch Filho, E.; Gonteski, D.; Lamos, M.; Leo, A.; Mulder, N.; Matubara, F.; Schramm, P.; Silva, R.; Quisberth, J.; Uritsky, G.; Kogut, A.; Lowe, L.; Mirel, P.; Lazear, J.

    2014-12-01

    In this project a multi-disciplinary undergraduate team from CUA, comprising majors in Physics, Mechanical Engineering, Electrical Engineering, and Biology, design, build, test, fly, and analyze the data from a prototype attitude determination system (PADS). The goal of the experiment is to determine if an inexpensive attitude determination system could be built for high altitude research balloons using MEMS gyros. PADS is a NASA funded project, built by students with the cooperation of CUA faculty, Verner, Bruhweiler, and Abot, along with the contributed expertise of researchers and engineers at NASA/GSFC, Kogut, Lowe, Mirel, and Lazear. The project was initiated through a course taught in CUA's School of Engineering, which was followed by a devoted effort by students during the summer of 2014. The project is an experiment to use 18 MEMS gyros, similar to those used in many smartphones, to produce an averaged positional error signal that could be compared with the motion of the fixed optical system as recorded through a string of optical images of stellar fields to be stored on a hard drive flown with the experiment. The optical system, camera microprocessor, and hard drive are enclosed in a pressure vessel, which maintains approximately atmospheric pressure throughout the balloon flight. The experiment uses multiple microprocessors to control the camera exposures, record gyro data, and provide thermal control. CUA students also participated in NASA-led design reviews. Four students traveled to NASA's Columbia Scientific Balloon Facility in Palestine, Texas to integrate PADS into a large balloon gondola containing other experiments, before being shipped, then launched in mid-August at Ft. Sumner, New Mexico. The payload is to fly at a float altitude of 40-45,000 m, and the flight last approximately 15 hours. The payload is to return to earth by parachute and the retrieved data are to be analyzed by CUA undergraduates. A description of the instrument is presented

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

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

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

  13. Benefits Assessment of Algorithmically Combining Generic High Altitude Airspace Sectors

    NASA Technical Reports Server (NTRS)

    Bloem, Michael; Gupta, Pramod; Lai, Chok Fung; Kopardekar, Parimal

    2009-01-01

    In today's air traffic control operations, sectors that have traffic demand below capacity are combined so that fewer controller teams are required to manage air traffic. Controllers in current operations are certified to control a group of six to eight sectors, known as an area of specialization. Sector combinations are restricted to occur within areas of specialization. Since there are few sector combination possibilities in each area of specialization, human supervisors can effectively make sector combination decisions. In the future, automation and procedures will allow any appropriately trained controller to control any of a large set of generic sectors. The primary benefit of this will be increased controller staffing flexibility. Generic sectors will also allow more options for combining sectors, making sector combination decisions difficult for human supervisors. A sector-combining algorithm can assist supervisors as they make generic sector combination decisions. A heuristic algorithm for combining under-utilized air space sectors to conserve air traffic control resources has been described and analyzed. Analysis of the algorithm and comparisons with operational sector combinations indicate that this algorithm could more efficiently utilize air traffic control resources than current sector combinations. This paper investigates the benefits of using the sector-combining algorithm proposed in previous research to combine high altitude generic airspace sectors. Simulations are conducted in which all the high altitude sectors in a center are allowed to combine, as will be possible in generic high altitude airspace. Furthermore, the algorithm is adjusted to use a version of the simplified dynamic density (SDD) workload metric that has been modified to account for workload reductions due to automatic handoffs and Automatic Dependent Surveillance Broadcast (ADS-B). This modified metric is referred to here as future simplified dynamic density (FSDD). Finally

  14. Sustained high-altitude hypoxia increases cerebral oxygen metabolism

    PubMed Central

    Smith, Zachary M.; Krizay, Erin; Guo, Jia; Shin, David D.; Scadeng, Miriam

    2013-01-01

    Acute mountain sickness (AMS) is a common condition occurring within hours of rapid exposure to high altitude. Despite its frequent occurrence, the pathophysiological mechanisms that underlie the condition remain poorly understood. We investigated the role of cerebral oxygen metabolism (CMRO2) in AMS. The purpose of this study was to test 1) if CMRO2 changes in response to hypoxia, and 2) if there is a difference in how individuals adapt to oxygen metabolic changes that may determine who develops AMS and who does not. Twenty-six normal human subjects were recruited into two groups based on Lake Louise AMS score (LLS): those with no AMS (LLS ≤ 2), and those with unambiguous AMS (LLS ≥ 5). [Subjects with intermediate scores (LLS 3–4) were not included.] CMRO2 was calculated from cerebral blood flow and arterial-venous difference in O2 content. Cerebral blood flow was measured using arterial spin labeling MRI; venous O2 saturation was calculated from the MRI of transverse relaxation in the superior sagittal sinus. Arterial O2 saturation was measured via pulse oximeter. Measurements were made during normoxia and after 2-day high-altitude exposure at 3,800 m. In all subjects, CMRO2 increased with sustained high-altitude hypoxia [1.54 (0.37) to 1.82 (0.49) μmol·g−1·min−1, n = 26, P = 0.045]. There was no significant difference in CMRO2 between AMS and no-AMS groups. End-tidal Pco2 was significantly reduced during hypoxia. Low arterial Pco2 is known to increase neural excitability, and we hypothesize that the low arterial Pco2 resulting from ventilatory acclimatization causes the observed increase in CMRO2. PMID:23019310

  15. NGC 1252: a high altitude, metal poor open cluster remnant

    NASA Astrophysics Data System (ADS)

    de la Fuente Marcos, R.; de la Fuente Marcos, C.; Moni Bidin, C.; Carraro, G.; Costa, E.

    2013-09-01

    If stars form in clusters but most stars belong to the field, understanding the details of the transition from the former to the latter is imperative to explain the observational properties of the field. Aging open clusters are one of the sources of field stars. The disruption rate of open clusters slows down with age but, as an object gets older, the distinction between the remaining cluster or open cluster remnant (OCR) and the surrounding field becomes less and less obvious. As a result, finding good OCR candidates or confirming the OCR nature of some of the best candidates still remain elusive. One of these objects is NGC 1252, a scattered group of about 20 stars in Horologium. Here we use new wide-field photometry in the UBVI passbands, proper motions from the Yale/San Juan SPM 4.0 catalogue and high-resolution spectroscopy concurrently with results from N-body simulations to decipher NGC 1252's enigmatic character. Spectroscopy shows that most of the brightest stars in the studied area are chemically, kinematically and spatially unrelated to each other. However, after analysing proper motions, we find one relevant kinematic group. This sparse object is relatively close (˜1 kpc), metal poor and is probably not only one of the oldest clusters (3 Gyr) within 1.5 kpc from the Sun but also one of the clusters located farthest from the disc, at an altitude of nearly -900 pc. That makes NGC 1252 the first open cluster that can be truly considered a high Galactic altitude OCR: an unusual object that may hint at a star formation event induced on a high Galactic altitude gas cloud. We also conclude that the variable TW Horologii and the blue straggler candidate HD 20286 are unlikely to be part of NGC 1252. NGC 1252 17 is identified as an unrelated, Population II cannonball star moving at about 400 km s-1.

  16. Reduced autonomic activity during stepwise exposure to high altitude.

    PubMed

    Sevre, K; Bendz, B; Hankø, E; Nakstad, A R; Hauge, A; Kåsin, J I; Lefrandt, J D; Smit, A J; Eide, I; Rostrup, M

    2001-12-01

    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 a hypobaric chamber to test the hypothesis of a temporary reduction in autonomic activity. The altitude was increased stepwise to 4500 m over 3 days. Heart rate variability (HRV) was assessed continuously in seven subjects. Baroreceptor reflex sensitivity (BRS) was determined in eight subjects with the 'Transfer Function' method at baseline, at 4500 m and after returning to baseline. Resting plasma catecholamines and cardiovascular- and plasma catecholamine- responses to cold pressor- (CPT) and mental stress-test (MST) were assessed daily in all and 12 subjects, respectively. Data are mean +/- SEM. Compared with baseline at 4500 m there were lower total power (TP) (35 457 +/- 26 302 vs. 15 001 +/- 11 176 ms2), low frequency (LF) power (3112 +/- 809 vs. 1741 +/- 604 ms2), high frequency (HF) power (1466 +/- 520 vs. 459 +/- 189 ms2) and HF normalized units (46 +/- 0.007 vs. 44 +/- 0.006%), P < or = 0.001. Baroreceptor reflex sensitivity decreased (15.6 +/- 2.1 vs. 9.5 +/- 2.6 ms mmHg(-1), P = 0.015). Resting noradrenaline (NA) decreased (522 +/- 98 vs. 357 +/- 60 pmol L(-1), P = 0.027). The increase in systolic blood pressure (SBP) and NA during mental stress was less pronounced (21 +/- 4 vs. 10 +/- 2% and 25 +/- 9 vs. -2 +/- 8%, respectively, P < 0.05). The increase in SBP during cold pressor test decreased (16 +/- 3 vs. 1 +/- 6%, P = 0.03). Diastolic blood pressure, HR and adrenaline displayed similar tendencies. We conclude that a transient reduction in parasympathetic and sympathetic activity was demonstrated during stepwise exposure to high altitude.

  17. Mössbauer studies of hemoglobin in high altitude polycythemia

    NASA Astrophysics Data System (ADS)

    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.

  18. High-Altitude Plasma Instrument for Dynamics Explorer-A

    NASA Astrophysics Data System (ADS)

    Burch, J. L.; Winningham, J. D.; Blevins, V. A.; Eaker, N.; Gibson, W. C.; Hoffman, R. A.

    1981-12-01

    The Dynamics Explorer A High-Altitude Plasma Instrument (HAPI) will make differential measurements of the velocity-space distributions of electrons and positive ions over the energy/charge range of 5 eV to 32 keV. Five identical analyzers, each making simultaneous measurements of electrons and positive ions at 64 possible energy levels, will have viewing angles of 45, 78, 90, 102, and 135 deg relative to the spacecraft spin axis. The HAPI data will contribute to the overall Dynamics Explorer science objectives, particularly by providing information on the hot-plasma effects of the coupling of energy, mass, and momentum within the earth's atmosphere, ionosphere, and magnetosphere.

  19. High-Altitude Plasma Instrument for Dynamics Explorer-A

    NASA Technical Reports Server (NTRS)

    Burch, J. L.; Winningham, J. D.; Blevins, V. A.; Eaker, N.; Gibson, W. C.; Hoffman, R. A.

    1981-01-01

    The Dynamics Explorer A High-Altitude Plasma Instrument (HAPI) will make differential measurements of the velocity-space distributions of electrons and positive ions over the energy/charge range of 5 eV to 32 keV. Five identical analyzers, each making simultaneous measurements of electrons and positive ions at 64 possible energy levels, will have viewing angles of 45, 78, 90, 102, and 135 deg relative to the spacecraft spin axis. The HAPI data will contribute to the overall Dynamics Explorer science objectives, particularly by providing information on the hot-plasma effects of the coupling of energy, mass, and momentum within the earth's atmosphere, ionosphere, and magnetosphere.

  20. High-Altitude Observations of the Polar Wind

    NASA Technical Reports Server (NTRS)

    Moore, T. E.; Chappell, C. R.; Chandler, M. O.; Craven, P. D.; Giles, B. L.; Pollock, C. J.; Burch, J. L.; Young, D. T.; Waite, J. H., Jr.; Nordholt, J. E.; Thomsen, M. F.; McComas, D. J.; Berthelier, J. J.; Williamson, W. S.; Robson, R.; Mozer, F. S.

    1997-01-01

    Plasma outflows, escaping from Earth through the high-altitude polar caps into the tail of the magnetosphere, have been observed with a xenon plasma source instrument to reduce the floating potential of the POLAR spacecraft. The largest component of H(+) flow, along the local magnetic field (30 to 60 kilometers per second), is faster than predicted by theory. The flows contain more O(+) than predicted by theories of thermal polar wind, but also have elevated ion temperatures. These plasma outflows contribute to the plasmas energized in the elongated nightside tail of the magnetosphere, creating auroras, substorms, and storms. They also constitute an appreciable loss of terrestrial water dissociation products into space.

  1. Sun sensing guidance system for high altitude aircraft

    NASA Technical Reports Server (NTRS)

    Reed, R. D. (Principal Investigator)

    1982-01-01

    A sun sensing guidance system for high altitude aircraft is described. The system is characterized by a disk shaped body mounted for rotation aboard the aircraft in exposed relation to solar radiation. The system also has a plurality of mutually isolated chambers; each chamber being characterized by an opening having a photosensor disposed therein and arranged in facing relation with the opening for receiving incident solar radiation and responsively providing a voltage output. Photosensors are connected in paired relation through a bridge circuit for providing heading error signals in response to detected imbalances in intensities of solar radiation.

  2. Studies on organ weights in naproxen treated rats after intermittent exposure to simulated high altitude

    NASA Astrophysics Data System (ADS)

    Saha, R. C.; Biswas, H. M.

    1990-06-01

    Rats were exposed intermittently for 8h per day over 6 days at simulated high altitude of 20 000 feet. One group of altitude-exposed animals was treated with naproxen, a prostaglandin inhibiting drug. Significant reduction in body weight gain was observed in both altitude-exposed and drug-treated altitude-exposed animals compared to the control group. Right and left ventricular weights and weights of the adrenal glands were increased significantly in altitude-exposed and altitude-exposed drug-treated animals. The weight of the spleen was increased significantly in altitude-exposed animals whereas no such increase of splenic weight was observed in drug-treated altitude-exposed group of animals. On the other hand, the weight of the liver was decreased significantly in both cases. In drug-treated altitude-exposed animals, the unaltered splenic weight was thought to be due to inhibition of the erythropoietic activity.

  3. Human Behaviour and Development under High-Altitude Conditions

    ERIC Educational Resources Information Center

    Virues-Ortega, Javier; Garrido, Eduardo; Javierre, Casimiro; Kloezeman, Karen C.

    2006-01-01

    Although we are far from a universally accepted pattern of impaired function at altitude, there is evidence indicating motor, perceptual, memory and behavioural deficits in adults. Even relatively low altitudes (2500 m) may delay reaction time, and impair motor function. Extreme altitude exposure (greater than 5000 m) may result in more pronounced…

  4. Reduced coagulation at high altitude identified by thromboelastography.

    PubMed

    Martin, Daniel S; Pate, Jim S; Vercueil, Andre; Doyle, Patrick W; Mythen, Michael G; Grocott, Mike P W

    2012-06-01

    The impact of hypoxaemia on blood coagulation remains unclear despite use of a variety of measures to address the issue. We report the first use of thromboelastography (TEG) at high altitude to describe the dynamics of clot formation in whole blood samples. Seventeen healthy volunteers ascended to 5,300 m following an identical ascent profile; TEG measurements at 4,250 m and 5,300 m were compared with those from sea level. Peripheral oxygen saturation (SpO2) and haematocrit were also measured. Ascent resulted in a decline in SpO2 from 97.8 (± 1.2) % at sea level to 86.9 (± 3.3) % at 4,250 m and 79.5 (± 5.8) % at 5,300 m (p<0.001); haematocrit rose from 43.7 (± 2.8) % at sea level, to 46.7 (± 3.9) % and 52.6 (± 3.2) % at 4,250 m and 5,300 m, respectively (p<0.01). TEG reaction (R)-time and kinetic (K)-time were both increased at 5,300 m compared to sea level, 8.95 (± 1.37) minutes (min) to 11.69 (± 2.91) min (p=0.016) and 2.40 (± 0.66) min to 4.99 (± 1.67) min (p<0.001), respectively. Additionally the alpha (α)-angle was decreased from 57.7 (± 8.2) to 51.6 (± 6.4) (p<0.001). There was no change in maximum amplitude (MA) on ascent to altitude. These changes are consistent with an overall pattern of slowed coagulation at high altitude.

  5. Respiratory control in residents at high altitude: physiology and pathophysiology.

    PubMed

    León-Velarde, Fabiola; Richalet, Jean-Paul

    2006-01-01

    Highland population (HA) from the Andes, living above 3000 m, have a blunted ventilatory response to increasing hypoxia, breathe less compared to acclimatized newcomers, but more, compared to sea-level natives at sea level. Subjects with chronic mountain sickness (CMS) breathe like sea-level natives and have excessive erythrocytosis (EE). The respiratory stimulation that arises through the peripheral chemoreflex is modestly less in the CMS group when compared with the HA group at the same P(ET(O2)). With regard to CO(2) sensitivity, CMS subjects seem to have reset their central CO(2) chemoreceptors to operate around the sea-level resting P(ET(CO2)). Acetazolamide, an acidifying drug that increases the chemosensitivity of regions in the brain stem that contain CO(2)/H(+) sensitive neurons, partially reverses this phenomenon, thus, providing CMS subjects with the possibility to have high CO(2) changes, despite small changes in ventilation. However, the same type of adjustments of the breathing pattern established for Andeans has not been found necessarily in Asian humans and/or domestic animals nor in the various high altitude species studied. The differing time frames of exposure to hypoxia among the populations, as well as the reversibility of the different components of the respiratory process at sea level, provide key concepts concerning the importance of time at high altitude in the evolution of an appropriate breathing pattern.

  6. Perseus High Altitude Remotely Piloted Aircraft on Ramp

    NASA Technical Reports Server (NTRS)

    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

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

    PubMed Central

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

    2013-01-01

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

  8. Work capacity of permanent residents of high altitude.

    PubMed

    Marconi, Claudio; Marzorati, Mauro; Cerretelli, Paolo

    2006-01-01

    Tibetan and Andean natives at altitude have allegedly a greater work capacity and stand fatigue better than acclimatized lowlanders. The principal aim of the present review is to establish whether convincing experimental evidence supports this belief and, should this be the case, to analyze the possible underlying mechanisms. The superior work capacity of high altitude natives is not based on differences in maximum aerobic power (V(O2 peak)), mL kg(-1)min(-1)). In fact, average V (O2 peak) of both Tibetan and Andean natives at altitude is only slightly, although not significantly, higher than that of Asian or Caucasian lowlanders resident for more than 1 yr between 3400 and 4700 m (Tibetans, n = 152, vs. Chinese Hans, n = 116: 42.4 +/- 3.4 vs. 39.2 +/- 2.6 mL kg(-1)min(-1), mean +/- SE; Andeans, n = 116, vs. Caucasians, n = 70: 47.1 +/- 1.7 vs. 41.6 +/- 1.2 mL kg(-1)min(-1)). However, compared to acclimatized lowlanders, Tibetans appear to be characterized by a better economy of cycling, walking, and running on a treadmill. This is possibly due to metabolic adaptations, such as increased muscle myoglobin content and antioxidant defense. All together, the latter changes may enhance the efficiency of the muscle oxidative metabolic machinery, thereby supporting a better prolonged submaximal performance capacity compared to lowlanders, despite equal V(O2 peak). With regard to Andeans, data on exercise efficiency is scanty and controversial and, at present, no conclusion can be drawn as to the origin of their superior performance.

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

    PubMed Central

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

    2015-01-01

    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. PMID:26459926

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

    NASA Astrophysics Data System (ADS)

    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.

  11. ER-2 High Altitude Solar Cell Calibration Flights

    NASA Technical Reports Server (NTRS)

    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.

  12. Depression and Altitude: Cross-Sectional Community-Based Study Among Elderly High-Altitude Residents in the Himalayan Regions.

    PubMed

    Ishikawa, Motonao; Yamanaka, Gaku; Yamamoto, Naomune; Nakaoka, Takashi; Okumiya, Kiyohito; Matsubayashi, Kozo; Otsuka, Kuniaki; Sakura, Hiroshi

    2016-03-01

    Suicide rates are higher at high altitudes, and some hypothesize that hypoxia is the cause. There may be a significant correlation between rates of depression and altitude, but little data exist outside the United States. The purpose of the present study is to conduct a survey of depression among the elderly highlanders in Asia. We enrolled 114 persons aged 60 years or older (mean, 69.2 ± 6.7 years; women, 58.8%) in Domkhar (altitude, 3800 m), Ladakh, India and 173 ethnic Tibetans (mean, 66.5 ± 6.1 years; women, 61.3%) in Yushu (altitude, 3700 m), Qinghai Province, China. The two-item Patient Health Questionnaire (PHQ-2) and the geriatric depression scale were administered. A psychiatrist interviewed the subjects who had a positive score on the PHQ-2. The results of the interview with the residents conducted by the specialist showed that two cases (1.8%) from Domkhar and four (2.3%) from Qinghai had depression. Despite the high altitude, the probability of depression was low in elderly highlander in Ladakh and Qinghai. Our finding seems to indicate that cultural factors such as religious outlook and social/family relationship inhibit the development of depression.

  13. High resolution spectroscopy from low altitude satellites. [gamma ray astronomy

    NASA Technical Reports Server (NTRS)

    Nakano, G. H.; Imhof, W. L.

    1978-01-01

    The P 78 1 satellite to be placed in a synchronous polar orbit at an altitude of 550-660 km will carry two identical high resolution spectrometers each consisting of a single (approximately 85 cc) intrinsic germanium IGE detector. The payload also includes a pair of phoswitch scintillators, an array of CdTe detectors and several particle detectors, all of which are mounted on the wheel of the satellite. The intrinsic high purity IGE detectors receive cooling from two Stirling cycle refrigerators and facilitate the assembly of large and complex detector arrays planned for the next generation of high sensitivity instruments such as those planned for the gamma ray observatory. The major subsystems of the spectrometer are discussed as well as its capabilities.

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

    ERIC Educational Resources Information Center

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

    2011-01-01

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

  15. Radiation Safety Issues in High Altitude Commercial Aircraft

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

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

  16. Scientific verification of High Altitude Water Cherenkov observatory

    NASA Astrophysics Data System (ADS)

    Marinelli, Antonio; Sparks, Kathryne; Alfaro, Ruben; González, María Magdalena; Patricelli, Barbara; Fraija, Nissim

    2014-04-01

    The High Altitude Water Cherenkov (HAWC) observatory is a TeV gamma-ray and cosmic-ray detector currently under construction at an altitude of 4100 m close to volcano Sierra Negra in the state of Puebla, Mexico. The HAWC [1] observatory is an extensive air-shower array composed of 300 optically isolated water Cherenkov detectors (WCDs). Each WCD contains ~200,000 l of filtered water and four upward-facing photomultiplier tubes. In Fall 2014, when the HAWC observatory will reach an area of 22,000 m2, the sensitivity will be 15 times higher than its predecessor Milagro [2]. Since September 2012, more than 30 WCDs have been instrumented and taking data. This first commissioning phase has been crucial for the verification of the data acquisition and event reconstruction algorithms. Moreover, with the increasing number of instrumented WCDs, it is important to verify the data taken with different configuration geometries. In this work we present a comparison between Monte Carlo simulation and data recorded by the experiment during 24 h of live time between 14 and 15 April of 2013 when 29 WCDs were active.

  17. Development and testing of airfoils for high-altitude aircraft

    NASA Technical Reports Server (NTRS)

    Drela, Mark (Principal Investigator)

    1996-01-01

    Specific tasks included airfoil design; study of airfoil constraints on pullout maneuver; selection of tail airfoils; examination of wing twist; test section instrumentation and layout; and integrated airfoil/heat-exchanger tests. In the course of designing the airfoil, specifically for the APEX test vehicle, extensive studies were made over the Mach and Reynolds number ranges of interest. It is intended to be representative of airfoils required for lightweight aircraft operating at extreme altitudes, which is the primary research objective of the APEX program. Also considered were thickness, pitching moment, and off-design behavior. The maximum ceiling parameter M(exp 2)C(sub L) value achievable by the Apex-16 airfoil was found to be a strong constraint on the pullout maneuver. The NACA 1410 and 2410 airfoils (inverted) were identified as good candidates for the tail, with predictable behavior at low Reynolds numbers and good tolerance to flap deflections. With regards to wing twist, it was decided that a simple flat wing was a reasonable compromise. The test section instrumentation consisted of surface pressure taps, wake rakes, surface-mounted microphones, and skin-friction gauges. Also, a modest wind tunnel test was performed for an integrated airfoil/heat-exchanger configuration, which is currently on Aurora's 'Theseus' aircraft. Although not directly related to the APEX tests, the aerodynamics or heat exchangers has been identified as a crucial aspect of designing high-altitude aircraft and hence is relevant to the ERAST program.

  18. Isothermal pumping analysis for high-altitude tethered balloons

    PubMed Central

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

    2015-01-01

    High-altitude tethered balloons have potential applications in communications, surveillance, meteorological observations and climate engineering. To maintain balloon buoyancy, power fuel cells and perturb atmospheric conditions, fluids could be pumped from ground level to altitude using the tether as a hose. This paper examines the pumping requirements of such a delivery system. Cases considered include delivery of hydrogen, sulfur dioxide (SO2) and powders as fluid-based slurries. Isothermal analysis is used to determine the variation of pressures and velocities along the pipe length. Results show that transport of small quantities of hydrogen to power fuel cells and maintain balloon buoyancy can be achieved at pressures and temperatures that are tolerable in terms of both the pipe strength and the current state of pumping technologies. To avoid solidification, transport of SO2 would require elevated temperatures that cannot be tolerated by the strength fibres in the pipe. While the use of particle-based slurries rather than SO2 for climate engineering can reduce the pipe size significantly, the pumping pressures are close to the maximum bursting pressure of the pipe. PMID:26543573

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

    PubMed

    Kuo, Kirsty A; Hunt, Hugh E M

    2015-06-01

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

  20. Ascending performance analysis for high altitude zero pressure balloon

    NASA Astrophysics Data System (ADS)

    Saleh, Sherif; He, Weiliang

    2017-04-01

    This paper describes a comprehensive simulation for high altitude zero pressure balloon trajectories. A mathematical model was established to simulate the ascending process which considers the atmospheric conditions and thermodynamic variations. Influences of launch parameters on ascending performance were analyzed. The necessary quantity of initial lift gas was estimated and optimized, so that ensures no ballast consuming during the ascending process. The climbing rate was a governing parameter to evaluate the ascending performance. Based on the simulation, results revealed the apparent different effect on climbing rate at troposphere and stratosphere layers. Change in launch time and site mainly affect the climbing rate at the stratosphere and have no significant effect at the troposphere and tropopause altitudes. Meanwhile, change in launch date has a negligible effect on both layers. Due to the earth's declination angle, the influence of the same launch latitude and the same launch longitude is not identical within a year. Also, results showed that the optimum lift gas quantity improved the climbing rate stability to obtain an accurate simulation.

  1. An Investigation into the Nature of High Altitude Cosmic Radiation in the Stratosphere

    ERIC Educational Resources Information Center

    Bancroft, Samuel; Bancroft, Ben; Greenwood, Jake

    2014-01-01

    An experiment was carried out to investigate the changes in ionizing cosmic radiation as a function of altitude. This was carried out using a Geiger-Müller tube on-board a high altitude balloon, which rose to an altitude of 31 685 m. The gathered data show that the Geiger-Müller tube count readings increased to a maximum at an altitude of about 24…

  2. Radiation Physics for Space and High Altitude Air Travel

    NASA Technical Reports Server (NTRS)

    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.

  3. Electric Power System for High Altitude UAV Technology Survey

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Electric powertrain technologies with application to high altitude Unmanned Aerial Vehicles (UAV) are assessed. One hundred twenty five solar electric UAV configurations and missions were simulated. Synergistic design opportunities were investigated with the premise that specific benefits may be realized, for example, if a single component can serve multiple functions, such as a battery being used for energy storage as well as for a structural component of the aircraft. For each UAV mission simulation, the airframe structure, powertrain configuration (type of solar cells, energy storage options) and performance baseline (1997 or 2001) were specified. It has been found that the use of the high efficiency (multijunction) solar cells or the use of the synergistic amorphous silicon solar cell configuration yields aircraft that can accomplish the majority of the missions of interest for any latitude between 0 deg and 55 deg, hence, a single versatile aircraft can be constructed and implemented to accomplish these missions.

  4. Thermoelectric Energy Conversion Technology for High-Altitude Airships

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Technical Reports Server (NTRS)

    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

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

    PubMed Central

    Anderson, Paul J.; Miller, Andrew D.; O’Malley, Kathy A.; Ceridon, Maile L.; Beck, Kenneth C.; Wood, Christina M.; Wiste, Heather J.; Mueller, Joshua J.; Johnson, Jacob B.; Johnson, Bruce D.

    2011-01-01

    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/m2) 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

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

    NASA Technical Reports Server (NTRS)

    Heymsfield, Gerald; Li, Li-Hua

    2005-01-01

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

  8. Passive microwave observations of thunderstorms from high-altitude aircraft

    NASA Technical Reports Server (NTRS)

    Heymsfield, Gerald M.; Fulton, Richard

    1988-01-01

    A high-altitude (20 km) aircraft made overflights of severe and nonsevere Midwest thunderstorms in the central and southeast U.S. during 2 separate experiments. Down-looking instruments on the aircraft are the imaging Multi-Channel Cloud Radiometer with channels in the visible, IR, and near IR, and two passive microwave instruments, the imaging Advanced Microwave Moisture Sounder at 92 (atmospheric window) and 183 GHz (centered on a water vapor line) and the 45 deg foward-of-nadir Multi-Channel Precipitation Radiometer at the 18 and 37 GHz window channels. Over land, the 92 GHz frequency distinguishes quite well the precipitating region from the nonprecipitating anvil region. The interpretation of the microwave measurements is complicated by differences in the cloud microphysics between different climatic regions.

  9. Risk assessment of high altitude free flight commercial aircraft operations

    SciTech Connect

    Kimura, C.Y.; Sandquist, G.M.; Slaughter, D.M.; Sanzo, D.L.

    1998-04-23

    A quantitative model is under development to assess the safety and efficiency of commercial aircraft operations under the Free Flight Program proposed for air traffic control for the US National Airspace System. The major objective of the Free Flight Program is to accommodate the dramatic growth anticipated in air traffic in the US. However, the potential impacts upon aircraft safety from implementing the Program have not been fully explored and evaluated. The model is directed at assessing aircraft operations at high altitude over the continental US airspace since this action is the initial step for Free Flight. Sequential steps with analysis, assessment, evaluation, and iteration will be required to satisfactorily accomplish the complete transition of US commercial aircraft traffic operations.

  10. A nominal set of high-altitude EMP environments

    SciTech Connect

    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.

  11. Dental fractures on acute exposure to high altitude.

    PubMed

    Zadik, Yehuda; Einy, Shmuel; Pokroy, Russell; Bar Dayan, Yaron; Goldstein, Liav

    2006-06-01

    There is little in the literature on dental restoration breakage in the aviation environment since reports of problems in combat aviators in War World II. We report two cases of dental fractures during acute exposure to a hypobaric environment. Case 1 was a young officer who suffered an amalgam restoration breakage during a 25,000-ft decompression chamber simulation. Case 2 occurred in an experienced aviator who had a tooth cusp fracture in a molar with a defective amalgam restoration during an unpressurized helicopter flight to 18,000 ft. In both cases, after removing the defective fillings, deep secondary caries were found; both teeth were successfully restored. Because hard-tissue tooth fracture during a high-altitude flight is a rare event, few flight surgeons or dentists are familiar with this phenomenon. We recommend regular dental examinations with careful assessment of previous dental restorations in aircrew subject to decompression.

  12. The High-Altitude Water Cherenkov Observatory: First Light

    NASA Astrophysics Data System (ADS)

    Weisgarber, Thomas

    2013-04-01

    The High-Altitude Water Cherenkov (HAWC) Observatory is under construction at Sierra Negra in the state of Puebla in Mexico. Operation began in September 2012, with the first 30 out of the final 300 water Cherenkov detectors deployed and in data acquisition. The HAWC Observatory is designed to record particle air showers from gamma rays and cosmic rays with TeV energies. Though the detector is only 10% complete, HAWC is already the world's largest water Cherenkov detector in the TeV band. In this presentation, I will summarize the performance of the detector to date and discuss preliminary observations of cosmic-ray and gamma-ray sources. I will also describe deployment plans for the remainder of the detector and outline prospects for TeV observations in the coming year.

  13. A NASA DC-8 conducts high-altitude hurricane studies

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This NASA Dryden Flight Research Center DC-8 takes off from Patrick Air Force Base to pursue its goal of collecting high- altitude information about Atlantic hurricanes and tropical storms. Flying at 35,000 to 40,000 feet, the plane is equipped with instruments to measure the storm's structure, environment and changes in intensity and tracking. The DC-8 is part of the NASA-led Atmospheric Dynamics and Remote Sensing program that includes other government weather researchers and the university community in a study of Atlantic hurricanes and tropical storms. The hurricane study, which lasts through September, is part of NASA's Earth Science enterprise to better understand the total Earth system and the effects of natural and human-induced changes on the global environment.

  14. ECC ozonesonde performance at high altitudes: Pump efficiency

    NASA Technical Reports Server (NTRS)

    Torres, A. L.

    1981-01-01

    The ECC ozonesonde sampling behavior was examined at pressures ranging from 60 to 6 hPa with the objective of evaluating uncertainties in high altitude ozone data caused by variations in pumping efficiency. The averaged pump efficiency correction curve for a 43 sample set of 3A type ECC pumps showed a 2-3% bias from the curve provided by the manufacturer. In addition, random pump to pump variations (2 sigma) + or - were 5% at 6 hPa. These values probably represent minimum errors since the pumps were from the same production batch. A seven sample set of the newer 4A type ECC pumps was examined, with similar findings as for the 3A types.

  15. NASA prepares aircraft for high-altitude hurricane studies

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This NASA Dryden Flight Research Center DC-8, on view at Patrick Air Force Base, stands ready to pursue its goal of collecting high-altitude information about Atlantic hurricanes and tropical storms. Flying at 35,000 to 40,000 feet, the plane is equipped with instruments to measure the storm's structure, environment and changes in intensity and tracking. The DC-8 is part of the NASA-led Atmospheric Dynamics and Remote Sensing program that includes other government weather researchers and the university community in a study of Atlantic hurricanes and tropical storms. The hurricane study, which lasts through September 1998, is part of NASA's Earth Science enterprise to better understand the total Earth system and the effects of natural and human-induced changes on the global environment.

  16. Recommendations for resuscitation after ascent to high altitude and in aircrafts.

    PubMed

    Chalkias, Athanasios; Georgiou, Marios; Böttiger, Bernd; Monsieurs, Koenraad G; Svavarsdóttir, Hildigunnur; Raffay, Violetta; Iacovidou, Nicoletta; Xanthos, Theodoros

    2013-09-01

    Human exposure to high altitude is increasing, through inhabitation of areas of high altitude, expansion of tourism into more remote areas, and air travel exposing passengers to typical altitudes equivalent to 8005 ft (2440 m). With ascent to high altitude, a number of acute and chronic physiological changes occur, influencing all systems of the human body. When considering that cardiac arrest is the second most common cause of death in the mountains and that up to 60% of the elderly have significant heart disease or other health problems, these changes are of particular importance as they may have a significant impact on resuscitation efforts. Current guidelines for resuscitation lack specific recommendations regarding treatment of cardiac arrest after ascent to high altitude or in aircraft. Therefore, we performed a comprehensive search in PubMed, CINAHL, Cochrane Library, and Scopus databases for studies relevant to resuscitation at high altitude. As no randomized trials evaluating the effects of physiological changes after ascent to high altitude on cardiopulmonary resuscitation were identified, our search was expanded to include all studies addressing important aspects on high altitude physiology which could have a potential impact on the resuscitation of cardiac arrest victims. The aim of this review is to discuss the major physiological changes occurring after ascent to high altitude and their potential effects on cardiopulmonary resuscitation. Based on the available data, specific suggestions are proposed regarding resuscitation at high altitude.

  17. A High-Altitude Search for Vulcanoids: Progress Report

    NASA Astrophysics Data System (ADS)

    Durda, D. D.; Stern, S. A.; Terrell, D. C.; Weidenschilling, S. J.

    2002-09-01

    We are conducting a unique, high-altitude observing campaign to search for vulcanoids, a population of small, asteroid-like bodies hypothesized to reside in the dynamically stable region interior to Mercury's orbit (i.e., orbits with aphelia <0.21 AU). This airborne search campaign utilizes our versatile and highly capable SWUIS-A (Southwest Universal Imaging System - Airborne) instrument flown with the flight astronomer (SAS and DDD) to an altitude of 49,000 MSL aboard NASA F/A-18B aircraft in order to obtain darker twilight conditions for near-Sun observing than are possible from the ground. The first observing run was successfully completed at NASA's Dryden Flight Research Center during the March/April 2002 vernal equinox observing opportunity. On each of the three evening flights we recorded image data covering 250 square degrees of sky centered on the ecliptic from solar elongations of 6-18 deg. Initial reduction of portions of the Mar/Apr 2002 data set demonstrates that we are reliably detecting objects to magnitude V = 9.5 at 15 degrees solar elongation. This is at least a magnitude fainter than the best previous ground-based searches and comparable to the faintest stars visible in our space-based SOHO LASCO C3 coronagraph vulcanoids search. The SWUIS-A instrument itself is capable of imaging objects as faint as magnitude V = 13, corresponding to vulcanoids less than 10 km across, with a sufficiently dark sky background; we are working to mitigate sky background brightness to reach these deeper magnitude limits for a second F/A-18B observing run during the September 2002 autumnal equinox observing opportunity. We thank NASA research pilots Rick Searfoss, Dana Purifoy, and Craig Bomben. This research is supported by the NASA Planetary Astronomy program, NASA's Dryden Flight Research Center, and the National Geographic Society.

  18. New horizons for the national high-altitude photography program

    USGS Publications Warehouse

    Bermel, Peter F.

    1983-01-01

    The National High-Altitude Photography Program (NHAP) is a multi-Federal agency activity to acquire uniform imagery for the establishment of a national high-altitude photographic data base. Federal agencies participating in NHAP have pooled their resources and consolidated photographic requirements in a systematic 6-year effort that will minimize duplication of photographic programs, reduce overall Federal expenditures for aerial photography, and provide imagery for a wide range of public and private users, The U.S. Geological Survey has the lead coordination role and shares, with the other participating agencies, the responsibility for funding the acquisition of photography. Since the inception of NHAP in 1980, black-and-white and color infrared stereoscopic imagery has been acquired for about 50% of the 3,000,000 square miles in the conterminous United States. An additional 40% of the 48-State area is under contract to provide aerial survey firms, and the sixth and final contract to achieve complete once-over coverage will be awarded early in 1985. Extensive use has been made of the newly established data base for mapping, landform studies, land use planning, natural resource inventory, evaluation and management, engineering, and education. In anticipation of the completion of once-over coverage, the participating agencies have begun studies to define the requirements for a maintenance program which would provide cyclic coverage of the conterminous United States and imagery for specific agency needs. Although continued funding at the same level is not assured, under consideration are requirements for new cameras, films, and other remote sensors, photographic parameters, and extension of program coverage to Alaska, Hawaii, and outlying areas. In addition, new applications of the data base to prepare cartographic map and data products are being investigated. It is becoming increasingly clear that some major decision needs to be made soon if a NHAP II is to begin in

  19. AltitudeOmics: enhanced cerebrovascular reactivity and ventilatory response to CO2 with high-altitude acclimatization and reexposure.

    PubMed

    Fan, Jui-Lin; Subudhi, Andrew W; Evero, Oghenero; Bourdillon, Nicolas; Kayser, Bengt; Lovering, Andrew T; Roach, Robert C

    2014-04-01

    The present study is the first to examine the effect of high-altitude acclimatization and reexposure on the responses of cerebral blood flow and ventilation to CO2. We also compared the steady-state estimates of these parameters during acclimatization with the modified rebreathing method. We assessed changes in steady-state responses of middle cerebral artery velocity (MCAv), cerebrovascular conductance index (CVCi), and ventilation (V(E)) to varied levels of CO2 in 21 lowlanders (9 women; 21 ± 1 years of age) at sea level (SL), during initial exposure to 5,260 m (ALT1), after 16 days of acclimatization (ALT16), and upon reexposure to altitude following either 7 (POST7) or 21 days (POST21) at low altitude (1,525 m). In the nonacclimatized state (ALT1), MCAv and V(E) responses to CO2 were elevated compared with those at SL (by 79 ± 75% and 14.8 ± 12.3 l/min, respectively; P = 0.004 and P = 0.011). Acclimatization at ALT16 further elevated both MCAv and Ve responses to CO2 compared with ALT1 (by 89 ± 70% and 48.3 ± 32.0 l/min, respectively; P < 0.001). The acclimatization gained for V(E) responses to CO2 at ALT16 was retained by 38% upon reexposure to altitude at POST7 (P = 0.004 vs. ALT1), whereas no retention was observed for the MCAv responses (P > 0.05). We found good agreement between steady-state and modified rebreathing estimates of MCAv and V(E) responses to CO2 across all three time points (P < 0.001, pooled data). Regardless of the method of assessment, altitude acclimatization elevates both the cerebrovascular and ventilatory responsiveness to CO2. Our data further demonstrate that this enhanced ventilatory CO2 response is partly retained after 7 days at low altitude.

  20. A Study of High Altitude Hypersonic Flow-Field Radiation

    NASA Technical Reports Server (NTRS)

    Moreau, Stephane; Park, Chul; Edwards, Thomas A. (Technical Monitor)

    1994-01-01

    This paper presents the results of the works carried out jointly at Stanford University and Ames Research Center under a grant from the Ballistic Missile Defense Organization (BMDO) (formerly the Strategic Defense Initiative Organization) to explain and understand the results of the two flight experiments, Bow Shock Ultra-Violet 1 and Bow Shock Ultra-Violet 2, carried out by the Organization. A portion of the material contained in this paper has been reported elsewhere in open literature. However, this paper provides (1) the details of scientific contents not available in those literature, (2) the links among those and the logical order of the efforts involved, and (3) some materials not contained in any open literature. The first author is responsible for execution of the work; the second author directed the work of the first author. In the two flight experiments mentioned above, the spectra of radiation in the ultraviolet wavelength range incident on the stagnation point of a blunt body were measured at the flight speeds of 3.8 and 5.2 km/sec over a wide range of altitudes. The results were compared first with the calculations made using the original version of the NEQAIR/STRAP codes written earlier by the second author. At low altitudes, the calculations agreed with the measurement. However, at high altitudes, the calculations underestimated the intensity of the radiation by several orders of magnitudes. A shock tube experiment was carried out at CALSPAN and a plasma-torch experiment was carried out at Stanford University to produce experimental data to help explain the discrepancy. In addition, the shock tube experiment at Ames Research Center carried out independently of the BMDO was also found to be relevant to this question. In this paper, several theoretical models are developed and calculations using the models were carried out to explain the results not only of the flight experiments but also of the CALSPAN, Stanford, and Ames experiments. The are: (1

  1. The HAMMER: High altitude multiple mission environmental researcher

    NASA Technical Reports Server (NTRS)

    Hayashi, Darren; Zylla, Cara; Amaro, Ernesto; Colin, Phil; Klause, Thomas; Lopez, Bernardo; Williamson, Danna

    1991-01-01

    At the equator, the ozone layer ranges from 65,000 to 130,000+ feet which is beyond the capabilities of the ER-2, NASA's current high altitude reconnaissance aircraft. The Universities Space Research Association, in cooperation with NASA, is sponsoring an undergraduate program which is geared to designing an aircraft that can study the ozone layer at the equator. This aircraft must be able to satisfy four mission profiles. Mission one is a polar mission which ranges from Chile to the South Pole and back to Chile, a total range of 6000 n. mi. at 100,000 feet with a 2500 lb. payload. The second mission is also a polar mission with a decreased altitude of 70,000 feet and an increased payload of 4000 lb. For the third mission, the aircraft will take-off at NASA Ames, cruise at 100,000 feet carrying a 2500 lb. payload, and land in Puerto Montt, Chile. The final mission requires the aircraft to take-off at NASA Ames, cruise at 100,000 feet with a 1000 lb. payload, make an excursion to 120,000 feet, and land at Howard AFB, Panama. All three missions require that a subsonic Mach number is maintained due to constraints imposed by the air sampling equipment. The aircraft need not be manned for all four missions. Three aircraft configurations were determined to be the most suitable for meeting the above requirements. The performance of each configuration is analyzed to investigate the feasibility of the project requirements. In the event that a requirement can not be obtained within the given constraints, recommendations for proposal modifications are given.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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.

  4. Medium and High Altitude Unmanned Aircraft System Acquisition: An Efficiency Study of Magnitude and Capability

    DTIC Science & Technology

    2009-06-12

    measures associated with a single entity acquisition authority for the selection of medium and high altitude UAS programs. Secondly, there will be no...MEDIUM AND HIGH ALTITUDE UNMANNED AIRCRAFT SYSTEM ACQUISITION : AN EFFICIENCY STUDY OF MAGNITUDE AND CAPABILITY A thesis...To) AUG 2009 – JUN 2009 4. TITLE AND SUBTITLE MEDIUM AND HIGH ALTITUDE UNMANNED AIRCRAFT SYSTEM (UAS) ACQUISITION : AN EFFICIENCY STUDY OF

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

    DTIC Science & Technology

    1983-05-15

    the research reported here was Dy- namics Explorer 1 (DE-1). The DE-1 High Altitude Plasma Instrument (HAPI) consists of five electrostatic analyzers...paper (Lin et al, 1983). The High Altitude Plasma Instrument (HAPI) on Dynamics Explorer 1 (DE-1) made differential flux measurements of electrons and...N. Eaker, W. C. Gibson, and R. A. Hoffman, High Altitude Plasma Instrument for Dynamics Explorer-A, Space Sci. Instrum., 5, 455, 1981. Burch, J. L

  6. [Pulmonary hypertension and lung edema at high altitude. Role of endothelial dysfunction and fetal programming].

    PubMed

    Schwab, Marcos; Allemann, Yves; Rexhaj, Emrush; Rimoldi, Stefano F; Sartori, Claudio; Scherrer, Urs

    2012-01-01

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

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

    PubMed

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

    2015-12-01

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

  8. Latest news from the High Altitude Water Cherenkov Observatory

    NASA Astrophysics Data System (ADS)

    González Muñoz, A.; HAWC Collaboration

    2016-07-01

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

  9. Health and Work at High Altitude - a Study of the Mauna-Kea Observatories

    NASA Astrophysics Data System (ADS)

    Forster, P. J. G.

    1984-06-01

    The low oxygen environment of high altitude decreases the efficiency and poses risks to the health of personnel manning telescopes at high altitudes. In a study at the Mauna Kea observatories (4200 m) in Hawaii, symptoms of acute mountain sickness were prevalent amongst telescope staff. Memory and psychomotor ability deteriorated on initial exposure to high altitude. Altitude-sickness symptoms abated and performance improved after several days on the mountain. Individual workers reacted to the stress of hypoxia in a reproducible manner on each ascent. Episodes of potentially fatal altitude sickness (pulmonary and cerebral edema) were unexpectedly rare. Provision for immediate descent and awareness of the hazards of hypoxia are the most effective precautions to ensure safe working at high-altitude-based observatories.

  10. The Use of Dexamethasone in Support of High-Altitude Ground Operations and Physical Performance: Review of the Literature

    DTIC Science & Technology

    2014-12-01

    cognition and maximal aerobic capacity in SOs who are susceptible to high-altitude pulmonary edema . 15. SUBJECT TERMS high altitude, mountain...capacity in SOs who are susceptible to high-altitude pulmonary edema . Keywords: high altitude, mountain, performance, strength, endurance, physical...nausea, headache, and peripheral edema .3-6 More severe cases of HHH may result in acute mountain sickness (AMS), high-altitude pulmonary edema

  11. Propulsion System for Very High Altitude Subsonic Unmanned Aircraft

    NASA Technical Reports Server (NTRS)

    Bents, David J.; Mockler, Ted; Maldonado, Jaime; Harp, James L., Jr.; King, Joseph F.; Schmitz, Paul C.

    1998-01-01

    This paper explains why a spark ignited gasoline engine, intake pressurized with three cascaded stages of turbocharging, was selected to power NASA's contemplated next generation of high altitude atmospheric science aircraft. Beginning with the most urgent science needs (the atmospheric sampling mission) and tracing through the mission requirements which dictate the unique flight regime in which this aircraft has to operate (subsonic flight at greater then 80 kft) we briefly explore the physical problems and constraints, the available technology options and the cost drivers associated with developing a viable propulsion system for this highly specialized aircraft. The paper presents the two available options (the turbojet and the turbocharged spark ignited engine) which are discussed and compared in the context of the flight regime. We then show how the unique nature of the sampling mission, coupled with the economic considerations pursuant to aero engine development, point to the spark ignited engine as the only cost effective solution available. Surprisingly, this solution compares favorably with the turbojet in the flight regime of interest. Finally, some remarks are made about NASA's present state of development, and future plans to flight demonstrate the three stage turbocharged powerplant.

  12. When is O+ Observed in the High Altitude Polar Cap?

    NASA Technical Reports Server (NTRS)

    Elliott, H. A.; Comfort, R. H.; Craven, P. D.; Chandler, M. O.; Moore, T. E.

    2000-01-01

    Solar wind and IMF properties are correlated with the properties of O+ and H+ in the polar cap at altitudes greater than 5.5 Re geocentric using the Thermal Ion Dynamics Experiment (TIDE) on the Polar satellite. O+ is of primary interest in this study because the fraction of O+ present in the magnetosphere is commonly used as a measure of the ionospheric contribution to the magnetosphere. O+ is observed to be most abundant at lower latitudes when the solar wind speed is low and across most of the polar cap at high solar winds speeds and Kp. As the solar wind dynamic pressures increases more O+ is present in the polar cap. The O+ density is also shown to be more highly correlated with the solar wind dynamic pressure when IMF Bz is positive. H+ was not as well correlated with solar wind and IMF parameters although some correlation with IMF By is observed. H+ is more plentiful when IMF By is negative than when it is positive. In this data set H+ is very dominate so that if this plasma makes it to the plasma sheet its contribution to the plasma sheet would have a very low O+ to H+ ratio.

  13. New particle formation events observed at a high altitude site Pico Espejo, Venezuela

    NASA Astrophysics Data System (ADS)

    Nieminen, Tuomo; Kontkanen, Jenni; Krejci, Radovan; Ström, Johan; Tunved, Peter; Hamburger, Thomas; Calderon, Silvia; Hoffman, Pedro

    2013-05-01

    Formation and growth events of nucleation mode particles (10-25 nm in diameter) were analyzed from 27 month period of particle size distribution measurements at the high altitude site Pico Espejo in Venezuela. Particle formation was observed both in air masses connected to boundary layer air and in free tropospheric conditions. The frequency and magnitude of particle formation at this high altitude site was comparable to many observations at lower altitude sites.

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

    DTIC Science & Technology

    1984-05-15

    High Altitude Plasma Instrument (HAPI) [Burch et al, 1981] on DE-1 are shown...Accreeration Regions, J. Geophys. Res. , 84, 5863, 1979. Burch, J. L., J. D. Winningham, V. A. Blevins, N. Eaker, W. C. Gibson, and R. A. Hoffman, High - altitude plasma instrument for... Altitude Plasma Instrument (HAPI) consists of five elec- trostatic analyzers mounted in a fan-shaped angular array at angles of 450, 780, 900, 1020,

  15. Radar-anomalous, high-altitude features on Venus

    NASA Technical Reports Server (NTRS)

    Muhleman, Duane O.; Butler, Bryan J.

    1992-01-01

    Over nearly all of the surface of Venus the reflectivity and emissivity at centimeter wavelengths are about 0.15 and 0.85 respectively. These values are consistent with moderately dense soils and rock populations, but the mean reflectivity is about a factor of 2 greater than that for the Moon and other terrestrial planets. Pettingill and Ford, using Pioneer Venus reflectivities and emissivities, found a number of anomalous features on Venus that showed much higher reflectivities and much lower emissivities with both values approaching 0.5. These include Maxwell Montes, a number of high regions in Aphrodite Terra and Beta Regio, and several isolated mountain peaks. Most of the features are at altitudes above the mean radius by 2 to 3 km or more. However, such features have been found in the Magellan data at low altitudes and the anomalies do not exist on all high structures, Maat Mons being the most outstanding example. A number of papers have been written that attempt to explain the phenomena in terms of the geochemistry balance of weathering effects on likely surface minerals. The geochemists have shown that the fundamentally basaltic surface would be stable at the temperatures and pressures of the mean radius in the form of magnetite, but would evolve to pyrite and/or pyrrhotite in the presence of sulfur-bearing compounds such as SO2. Pyrite will be stable at altitudes above 4 or 5 km on Venus. Although the geochemical arguments are rather compelling, it is vitally important to rationally look at other explanations for radar and radio emission measurements such as that presented by Tryka and Muhleman. The radar reflectivity values are retrieved from the raw Magellan backscatter measurements by fitting the Hagfors' radar scattering model in which a surface roughness parameters and a normal incidence electrical reflectivity are estimated. The assumptions of the theory behind the model must be considered carefully before the results can be believed. These include

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

    PubMed

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

    2010-12-25

    Weight loss is frequently observed after acute exposure to high altitude. However, the magnitude and rate of weight loss during acute exposure to high altitude has not been clarified in a controlled prospective study. The present study was performed to evaluate weight loss at high altitude. A group of 120 male subjects [aged (32±6) years] who worked on the construction of the Golmud-Lhasa Railway at Kunlun Mountain (altitude of 4 678 m) served as volunteer subjects for this study. Eighty-five workers normally resided at sea level (sea level group) and 35 normally resided at an altitude of 2 200 m (moderate altitude group). Body weight, body mass index (BMI), and waist circumference were measured in all subjects after a 7-day stay at Golmud (altitude of 2 800 m, baseline measurements). Measurements were repeated after 33-day working on Kunlun Mountain. In order to examine the daily rate of weight loss at high altitude, body weight was measured in 20 subjects from the sea level group (sea level subset group) each morning before breakfast for 33 d at Kunlun Mountain. According to guidelines established by the Lake Louise acute mountain sickness (AMS) consensus report, each subject completed an AMS self-report questionnaire two days after arriving at Kunlun Mountain. After 33-day stay at an altitude of 4 678 m, the average weight loss for the sea level group was 10.4% (range 6.5% to 29%), while the average for the moderate altitude group was 2.2% (-2% to 9.1%). The degree of weight loss (Δ weight loss) after a 33-day stay at an altitude of 4 678 m was significantly correlated with baseline body weight in the sea level group (r=0.677, P<0.01), while the correlation was absent in the moderate altitude group (r=0.296, P>0.05). In the sea level subset group, a significant weight loss was observed within 20 d, but the weight remained stable thereafter. AMS-score at high altitude was significantly higher in the sea level group (4.69±2.48) than that in the moderate

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

    PubMed

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

    2016-01-01

    Hypersensitive C-reaction protein (hsCRP) may be a risk factor for cognitive impairment resulting from Alzheimer's disease (AD), stroke, and vascular dementia. This study explored the correlation of peripheral blood hsCRP level with cognitive decline due to high altitude exposure. The study was conducted on 100 male military participants who had never been to high altitude. Cerebral oxygen saturation monitoring, event related potentials (P300, N200) detection, and neurocognitive assessment was performed and total hsCRP, interleukin-6 (IL-6), and homocysteine was estimated at 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.

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

    NASA Technical Reports Server (NTRS)

    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.

  19. The scavenging of high altitude aerosol by small ice crystals

    NASA Astrophysics Data System (ADS)

    Andrew Bell, D.; Saunders, Clive P. R.

    There have been several global models developed for the theoretical investigation of the removal of high altitude aerosol from the atmosphere, following concern about the injection of particulate material by nuclear explosions and volcanic events. These models lack a knowledge of the scavenging efficiencies of the small ice crystals associated with cirus clouds and storm ice anvils. These are the only hydrometers that could remove the injected particles. In the past there have been a number of practical studies into the scavenging efficiencies of large ice crystaks and snowflakes. A comparison of the extrapolated results of these findings and the theoretical models of Martin et al. (1980, Pure appl. Phys.188, 1109-1129, J. atmos. Sci.37, 1628-1638) for the small crystal situation has been made. It was found that in general the extrapolated results gave efficiencies that were significantly higher than the predicted value. This difference was found to be enhanced as the crystal diameter decreased. Experiments used small ice plates grown at ˜-18.5°C in a cloud chamber, which were then permitted to fall through a dense aerosol cloud, to provide the first direct measurements of the scavenging efficiencies of this small crystals under cloud conditions. Initial results are presented for mono-disperse NaCl aerosol particles of size 4-6 μm.

  20. Exposure to high altitude: a risk factor for venous thromboembolism?

    PubMed

    Gupta, Neha; Ashraf, Mohammad Z

    2012-03-01

    There are several genetic and acquired risk factors for venous thromboembolism. Exposure to high altitude (HA), either during air travel, ascension of mountains, or while engaging in sports activities, has been observed to result in a hypercoagulable state, thus predisposing to thromboembolic events. Although several previous studies have suggested that conditions present at HAs contribute to establish a prothrombotic milieu, published reports are contradictory and the exact underlying mechanism remains poorly understood. Results from HA studies also show that environmental conditions at HA such as hypoxia, dehydration, hemoconcentration, low temperature, use of constrictive clothing as well as enforced stasis due to severe weather, would support the occurrence of thrombotic disorders. The three leading factors of Virchow triad, that is, venous stasis, hypercoagulability, and vessel-wall injury, all appear to be present at HA. In synthesis, the large list of environmental variables suggests that a single cause of HA-induced thromboembolic disorders (TED) may not exist, so that this peculiar phenomenon should be seen as a complex or multifactorial trait. Further investigation is needed to understand the risk of TED at HA as well as the possible underlying mechanisms.

  1. Dermatoglyphics of a high altitude Peruvian population and interpopulation comparisons.

    PubMed

    Baca, O R; Del Valle Mendoza, L; Guerrero, N A

    2001-01-01

    Studies of genetic structures of Andean human populations have not been numerous, even though these studies could be used to answer questions concerning migration routes of the indigenous peoples who populated America. Such studies could provide basic genetic information and clarify uncertainties surrounding genetic relatedness of South American indigenous peoples. This present work describes, quantifies, and analyzes the digital and palmar dermatoglyphics of 120 people in the community of San Pedro de Casta, Perú. The results were then compared using distance analysis to all other Peruvian population values studied to date and other South American populations. The dermatoglyphic indicators studied were the distribution of digital pattern frequencies, the total ridge counts (TRC), the pattern intensity index (PII), the atd angle, and the a-b ridge counts. The results did not show statistically significant differences for digital patterns between hands, neither within a sex nor between sexes. The means and standard deviations of PII and TRC were 12.32 +/- 3.97 and 112.18 +/- 45.09, respectively. The means and standard deviations for the other two indicators were the following: atd angle, 94.85 degrees +/- 12.33; and a-b ridge counts, 81.57 +/- 9.06. The distance analyses results suggest the existence of two different genetic lines among high altitude populations, as well as the need for further research.

  2. Phenomenological investigations in high-altitude EMP (HEMP)

    SciTech Connect

    Cabayan, H.S.

    1984-07-01

    This report describes the presently available state-of-the-art analysis tools and extensions of these that are applicable to enhancing our understanding of the interaction and coupling phenomena associated with the high-altitude nuclear electromagnetic pulse (HEMP) and its effects on military systems. Such an in-depth understanding would provide the framework for a more scientific approach to system testing and hardening. In the report, we also briefly review past research programs in this area and evaluate the degree of their success. The emphasis in system assessment tools is placed on a probabilistic failure analysis approach that can provide a framework for vulnerabilities assessment and hardening. In coupling the emphasis is placed on a phenomenological understanding which involves a multifaceted approach involving analytical, computational, and experimental techniques in a complementary way. In component susceptibility, the emphasis is on the development of validated one, two and possibly three dimensional computer models that include the major physical phenomena such as heat and electronic transport equations. A gap exists in being able to express physics quantities in these codes in terms of nonlinear circuit parameters that can be used in the circuit codes.

  3. 21st Century Lightning Protection for High Altitude Observatories

    NASA Astrophysics Data System (ADS)

    Kithil, Richard

    2013-05-01

    One of the first recorded lightning insults to an observatory was in January 1890 at the Ben Nevis Observatory in Scotland. In more recent times lightning has caused equipment losses and data destruction at the US Air Force Maui Space Surveillance Complex, the Cerro Tololo observatory and the nearby La Serena scientific and technical office, the VLLA, and the Apache Point Observatory. In August 1997 NOAA's Climate Monitoring and Diagnostic Laboratory at Mauna Loa Observatory was out of commission for a month due to lightning outages to data acquisition computers and connected cabling. The University of Arizona has reported "lightning strikes have taken a heavy toll at all Steward Observatory sites." At Kitt Peak, extensive power down protocols are in place where lightning protection for personnel, electrical systems, associated electronics and data are critical. Designstage lightning protection defenses are to be incorporated at NSO's ATST Hawaii facility. For high altitude observatories lightning protection no longer is as simple as Franklin's 1752 invention of a rod in the air, one in the ground and a connecting conductor. This paper discusses selection of engineered lightning protection subsystems in a carefully planned methodology which is specific to each site.

  4. High altitude hypoxia and blood pressure dysregulation in adult chickens.

    PubMed

    Herrera, E A; Salinas, C E; Blanco, C E; Villena, M; Giussani, D A

    2013-02-01

    Although it is accepted that impaired placental perfusion in complicated pregnancy can slow fetal growth and programme an increased risk of cardiovascular dysfunction at adulthood, the relative contribution of reductions in fetal nutrition and in fetal oxygenation as the triggering stimulus remains unclear. By combining high altitude (HA) with the chick embryo model, we have previously isolated the direct effects of HA hypoxia on embryonic growth and cardiovascular development before hatching. This study isolated the effects of developmental hypoxia on cardiovascular function measured in vivo in conscious adult male and female chickens. Chick embryos were incubated, hatched and raised at sea level (SL, nine males and nine females) or incubated, hatched and raised at HA (seven males and seven females). At 6 months of age, vascular catheters were inserted under general anaesthesia. Five days later, basal blood gas status, basal cardiovascular function and cardiac baroreflex responses were investigated. HA chickens had significantly lower basal arterial PO2 and haemoglobin saturation, and significantly higher haematocrit than SL chickens, independent of the sex of the animal. HA chickens had significantly lower arterial blood pressure than SL chickens, independent of the sex of the animal. Although the gain of the arterial baroreflex was decreased in HA relative to SL male chickens, it was increased in HA relative to SL female chickens. We show that development at HA lowers basal arterial blood pressure and alters baroreflex sensitivity in a sex-dependent manner at adulthood.

  5. ASTER Views A High Altitude Tibetan Lake In Stereo

    NASA Astrophysics Data System (ADS)

    Matthews, J. P.; Wallis, S. R.; Yamaguchi, Y.

    2004-10-01

    The lakes of the Tibetan Plateau (Figure 1) have been investigated by Western and Chinese scientists over many years[e.g., Gasse et al., 1991; Zheng, 1997]. They are often located in extremely remote and inhospitable terrain at altitudes above 4000 m and, as a result, boat-based research campaigns aimed toward an improved understanding of the limnology and limnogeology of these water bodies are time consuming and difficult to perform. In order to support recent field studies of the Tibetan lakes, high spatial resolution imagery acquired by ASTER (the Advanced Spaceborne Thermal Emission and Reflection Radiometer) has been used. These data were gathered in the visible, near-infrared, and thermal infrared bands as ASTER operated on the TERRA platform[ Yamaguchi et al., 1998], a component of NASA's Earth Observing System (EOS). The research outlined here has benefited, in particular, from the availability of stereo data gathered by ASTER, in which regions are imaged first at nadir and then from a backward looking slant view some 55 s later in the near-infrared (channel 3B, 0.781-0.86μm).

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

    PubMed

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

    2014-03-15

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

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

    PubMed

    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.

  8. An artificially constructed Syngonium podophyllum-Aspergillus niger combinate system for removal of uranium from wastewater.

    PubMed

    He, Jia-dong; Wang, Yong-dong; Hu, Nan; Ding, Dexin; Sun, Jing; Deng, Qin-wen; Li, Chang-wu; Xu, Fei

    2015-12-01

    Aspergillus niger was inoculated to the roots of five plants, and the Syngonium podophyllum-A. niger combinate system (SPANCS) was found to be the most effective in removing uranium from hydroponic liquid with initial uranium concentration of 5 mg L(-1). Furthermore, the hydroponic experiments on the removal of uranium from the hydroponic liquids with initial uranium concentrations of 0.5, 1.0, and 3.0 mg L(-1) by the SPANCS were conducted, the inhibitory effect of A. niger on the growth of S. podophyllum in the SPANCS was studied, the accumulation characteristics of uranium by S. podophyllum in the SPANCS were analyzed, and the Fourier transform infrared (FT-IR) and extended X-ray absorption fine structure (EXAFS) spectra were measured. The results show that the removal of uranium by the SPANCS from the hydroponic liquids with initial uranium concentrations of 0.5, 1.0, and 3.0 mg L(-1) reached 98.20, 97.90, and 98.50%, respectively, after 37 days of accumulation of uranium; that the uranium concentrations in the hydroponic liquids decreased to 0.009, 0.021, and 0.045 mg L(-1), respectively, which are lower than the stipulated concentration for discharge of 0.050 mg L(-1) by the People's Republic of China; that A. niger helped to generate more groups in the root of S. podophyllum which can improve the complexing capability of S. podophyllum for uranium; and that the uranium accumulated in the root of S. podophyllum was in the form of phosphate uranyl and carboxylic uranyl.

  9. Hands-on Space Exploration through High Altitude Ballooning

    NASA Astrophysics Data System (ADS)

    Hammergren, Mark; Gyuk, G.

    2010-01-01

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

  10. High Altitude Aerial Natural Gas Leak Detection System

    SciTech Connect

    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.

  11. Cardio-pulmonary interactions at high altitude. Pulmonary hypertension as a common denominator.

    PubMed

    Maggiorini, Marco

    2003-01-01

    The purpose of this review is to find the evidence that a disproportionate pulmonary vasoconstriction persisting for days, weeks and years during residence at high altitude is the common pathophysiologic mechanism of high altitude pulmonary edema (HAPE), subacute mountain sickness and chronic mountain sickness. A recent finding in early HAPE suggests that transmission of excessively elevated pulmonary artery pressure to the pulmonary capillaries leading to alveolar hemorrhage as the pathophysiologic mechanism of HAPE. The elevated incidence of HAPE in Indian soldiers led the Indian Army to extend the acclimatization period from a few days to 5 weeks. Using this protocol, HAPE was prevented, but after several weeks of residence at an altitude of 6000m dyspnea, anasarca and pleuro-pericardial effusion developed. Clinical examination revealed severe congestive right heart failure. This condition has been previously described in long-term high altitude residents of the Himalaya and the Andes. In rats, smooth muscle cells appear in normally non-muscular arterioles within days of simulated altitude. Rapid remodeling of the small precapillary arteries may prevent HAPE but increase pulmonary vascular resistance leading to pulmonary hypertension in long-term high altitude residents. Symptoms and signs of HAPE, subacute mountain sickness and chronic mountain sickness reverse completely after residents are transfered to low altitude. In conclusion, these findings strongly suggest that pulmonary hypertension at high altitude, which could be named "high altitude pulmonary hypertension", is the principal and common pathogenic factor of all three cardio-pulmonary manifestations of high altitude illness. Accordingly, subacute mountain sickness and chronic mountain sickness could be renamed in "acute-" and "chronic right heart failure of high altitude", respectively.

  12. Active Learning in the Atmospheric Science Classroom and beyond through High-Altitude Ballooning

    ERIC Educational Resources Information Center

    Coleman, Jill S. M.; Mitchell, Melissa

    2014-01-01

    This article describes the implementation of high-altitude balloon (HAB) research into a variety of undergraduate atmospheric science classes as a means of increasing active student engagement in real-world, problem-solving events. Because high-altitude balloons are capable of reaching heights of 80,000-100,000 ft (24-30 km), they provide a…

  13. 40 CFR 600.310-86 - Labeling of high altitude vehicles.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Labeling of high altitude vehicles... Regulations for 1977 and Later Model Year Automobiles-Labeling § 600.310-86 Labeling of high altitude vehicles. (a) The Administrator may approve, at the request of the manufacturer, specific labels for...

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

    PubMed

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

    2015-12-22

    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.

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

    PubMed Central

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

    2015-01-01

    The low atmospheric pressure and low oxygen content in high-altitude environment have great impacts on the functions of human body. Especially for the personnel engaged in complicated physical labor such as tunnel construction, high altitude can cause a series of adverse physiological reactions, which may result in multiple high-altitude diseases and even death in severe cases. Artificial oxygen supply is required to ensure health and safety of construction personnel in hypoxic environments. However, there are no provisions for oxygen supply standard for tunnel construction personnel in high-altitude areas in current tunnel construction specifications. As a result, this paper has theoretically studied the impacts of high-altitude environment on human bodies, analyzed the relationship between labor intensity and oxygen consumption in high-altitude areas and determined the critical oxygen-supply altitude values for tunnel construction based on two different standard evaluation systems, i.e., variation of air density and equivalent PIO2. In addition, it has finally determined the oxygen supply standard for construction personnel in high-altitude areas based on the relationship between construction labor intensity and oxygen consumption. PMID:26703703

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

    NASA Technical Reports Server (NTRS)

    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.

  17. Iridium: Global OTH data communications for high altitude scientific ballooning

    NASA Astrophysics Data System (ADS)

    Denney, A.

    While the scientific community is no stranger to embracing commercially available technologies, the growth and availability of truly affordable cutting edge technologies is opening the door to an entirely new means of global communications. For many years high altitude ballooning has provided science an alternative to costly satellite based experimental platforms. As with any project, evolution becomes an integral part of development. Specifically in the NSBF ballooning program, where flight durations have evolved from the earlier days of hours to several weeks and plans are underway to provide missions up to 100 days. Addressing increased flight durations, the harsh operational environment, along with cumbersome and outdated systems used on existing systems, such as the balloon vehicles Support Instrumentation Package (SIP) and ground-based systems, a new Over-The-Horizon (OTH) communications medium is sought. Current OTH equipment planning to be phased-out include: HF commanding systems, ARGOS PTT telemetry downlinks and INMARSAT data terminals. Other aspects up for review in addition to the SIP to utilize this communications medium include pathfinder balloon platforms - thereby, adding commanding abilities and increased data rates, plus providing a package for ultra-small experiments to ride aloft. Existing communication systems employed by the National Scientific Balloon Facility ballooning program have been limited not only by increased cost, slow data rates and "special government use only" services such as TDRSS (Tracking and Data Relay Satellite System), but have had to make special provisions to geographical flight location. Development of the Support Instrumentation Packages whether LDB (Long Duration Balloon), ULDB (Ultra Long Duration Balloon) or conventional ballooning have been plagued by non-standard systems configurations requiring additional support equipment for different regions and missions along with a myriad of backup for redundancy. Several

  18. Cognitive Impairment of School Children at High Altitude: The Case for Oxygen Conditioning in Schools.

    PubMed

    West, John B

    2016-09-01

    West, John B. Cognitive impairment of school children at high altitude: the case for oxygen conditioning in schools. High Alt Med Biol. 17:203-207, 2016.-The hypoxia of high altitude frequently affects cognitive function. Recent work has shown that high altitude impairs the neuropsychological function of children of school age when compared with a similar control group of children at low altitude. This implies that the learning process is compromised at high altitude. One option is to bus children down to a lower altitude for schooling, but this is generally impracticable. Recently the new technique of oxygen conditioning has been introduced. The procedure is similar to air conditioning except that instead of altering the temperature of the air, the oxygen concentration is increased, thus raising the PO2 in the inspired air of classrooms. The result is that the children are physiologically at a lower altitude. Just as in very hot or cold climates, it is now unacceptable to have schools that are not air conditioned; in the future the same may apply to schools at high altitude that are not oxygen conditioned.

  19. Oviposition of aquatic insects in a tropical high altitude stream.

    PubMed

    Rios-Touma, Blanca; Encalada, A C; Prat, N

    2012-12-01

    The persistence of aquatic insect populations in streams depends on the recruitment of larval populations from egg masses deposited by adults, especially after disturbance. However, recruitment of aquatic populations by oviposition is a process that remains unstudied in streams and rivers. The objectives of our study were to document flying and oviposition patterns of aquatic insects in a high altitude tropical stream during both dry and wet seasons. In particular we studied 1) richness and abundance of adult forms of aquatic insects flying and ovipositing; 2) number of eggs (oviposition pattern), egg mass identity, and morphology; and 3) substrate preferences by ovipositing females. We found 2,383 aquatic insects corresponding to 28 families, with dipterans representing 89% of total individuals collected. Adult insects had lower richness (28 taxa) than larval diversity (up to 52 taxa) and distinct community composition. Richness and relative abundance of most taxa (adults) were not significantly different between seasons, behaviors, diel period, or all three. During both sampling periods we found females with eggs in a total of 15 different families (13 in the dry season and 14 in the wet season). There were no significant differences in the proportion of females with eggs between seasons, diel periods, or different behaviors (flying versus ovipositing traps) of the different female taxa. Few types of egg masses were found in rocks at the stream during both seasons, and most egg masses found corresponded to families Baetidae and Chironomidae. Finally, we provide the first description of eggs masses (size, shape, color, and number of eggs per female) of gravid females (10 taxa) and those found in the stream substrate (six taxa) of Andean macroinvertebrates. This is the first study reporting oviposition, adult diversity, and oviposition patterns of aquatic insects in the Andean region.

  20. Effect of high altitude on blood glucose meter performance.

    PubMed

    Fink, Kenneth S; Christensen, Dale B; Ellsworth, Allan

    2002-01-01

    Participation in high-altitude wilderness activities may expose persons to extreme environmental conditions, and for those with diabetes mellitus, euglycemia is important to ensure safe travel. We conducted a field assessment of the precision and accuracy of seven commonly used blood glucose meters while mountaineering on Mount Rainier, located in Washington State (elevation 14,410 ft). At various elevations each climber-subject used the randomly assigned device to measure the glucose level of capillary blood and three different concentrations of standardized control solutions, and a venous sample was also collected for later glucose analysis. Ordinary least squares regression was used to assess the effect of elevation and of other environmental potential covariates on the precision and accuracy of blood glucose meters. Elevation affects glucometer precision (p = 0.08), but becomes less significant (p = 0.21) when adjusted for temperature and relative humidity. The overall effect of elevation was to underestimate glucose levels by approximately 1-2% (unadjusted) for each 1,000 ft gain in elevation. Blood glucose meter accuracy was affected by elevation (p = 0.03), temperature (p < 0.01), and relative humidity (p = 0.04) after adjustment for the other variables. The interaction between elevation and relative humidity had a meaningful but not statistically significant effect on accuracy (p = 0.07). Thus, elevation, temperature, and relative humidity affect blood glucose meter performance, and elevated glucose levels are more greatly underestimated at higher elevations. Further research will help to identify which blood glucose meters are best suited for specific environments.

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

    PubMed

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

    2016-07-01

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

  2. Cardiopulmonary pathology among children resident at high altitude in Tintaya, Peru: a cross-sectional study.

    PubMed

    Huicho, Luis; Niermeyer, Susan

    2006-01-01

    Symptomatic high-altitude pulmonary hypertension and structural cardiac abnormalities related to high altitude have been reported previously. However, their true prevalence has not been systematically determined. We assessed clinical indicators of cardiovascular health or disease and correlated them with anatomic and physiologic cardiovascular features in preschool and schoolchildren living at 4000 m. We also estimated the prevalence of cardiovascular problems in the population, with emphasis on symptomatic high altitude pulmonary hypertension and structural cardiopathies. Three hundred and twenty-six children residents of Tintaya, Peru, were cross-sectionally studied. Methods included structured interviews, anthropometry and physical examination, arterial oxygen saturation, hemoglobin determination, electrocardiography, and echocardiography. The prevalence of structural cardiac problems was 1.5%, with less than 1% possibly attributable to high altitude. All children with structural cardiac abnormalities were identified by a focused physical exam prior to echocardiography. None were identified by the health interview. No symptomatic high altitude pulmonary hypertension was identified in the absence of underlying structural anomalies. The prevalence of structural cardiac problems was consistent with data from sea level. Active monitoring of the health status of a pediatric population at high altitude is valuable in the timely detection of cardiac abnormalities. Although our study children enjoyed generally excellent health, comparative, longitudinal studies are warranted to determine the incidence of high altitude cardiopulmonary problems and to identify risk factors and early markers for later disorders associated to life at high altitude. Our findings are applicable to children with some degree of high altitude genetic background and high mobility patterns to lower altitudes and living in comparatively good nutritional and socioeconomic conditions.

  3. Bats aloft: Variation in echolocation call structure at high altitudes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bats alter their echolocation calls in response to changes in ecological and behavioral conditions, but little is known about how they adjust their call structure in response to changes in altitude. This study examines altitudinal variation in the echolocation calls of Brazilian free-tailed bats, T...

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

    PubMed

    Riley, Callum James; Gavin, Matthew

    2017-03-15

    Riley, Callum James, and Matthew Gavin. Physiological changes to the cardiovascular system at high altitude and its effects on cardiovascular disease. High Alt Med Biol. 00:000-000, 2017.-The physiological changes to the cardiovascular system in response to the high altitude environment are well understood. More recently, we have begun to understand how these changes may affect and cause detriment to cardiovascular disease. In addition to this, the increasing availability of altitude simulation has dramatically improved our understanding of the physiology of high altitude. This has allowed further study on the effect of altitude in those with cardiovascular disease in a safe and controlled environment as well as in healthy individuals. Using a thorough PubMed search, this review aims to integrate recent advances in cardiovascular physiology at altitude with previous understanding, as well as its potential implications on cardiovascular disease. Altogether, it was found that the changes at altitude to cardiovascular physiology are profound enough to have a noteworthy effect on many forms of cardiovascular disease. While often asymptomatic, there is some risk in high altitude exposure for individuals with certain cardiovascular diseases. Although controlled research in patients with cardiovascular disease was largely lacking, meaning firm conclusions cannot be drawn, these risks should be a consideration to both the individual and their physician.

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

    NASA Astrophysics Data System (ADS)

    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.

  6. Snow chemistry of high altitude glaciers in the French Alps

    NASA Astrophysics Data System (ADS)

    Maupetit, François; Delmas, Robert J.

    1994-09-01

    Snow samples were collected as snowcores in the accumulation zone of four high altitude glaciers (2980 3540m.a.s.l.) from each of the 4 highest mountain areas of the French Alps, during 3 consecutive years: 1989, 1990 and 1991. Sampling was performed in spring (˜ May), before the onset of late spring summer percolation. The accumulated snow therefore reflects winter and spring conditions. A complementary sampling of fresh-snow was performed on an event basis, on one of the studied glaciers, in 1990 and 1991. All samples were analysed for major ions (but also for total formate and acetate in fresh-snow samples) using ion chromatography. The acidity-alkalinity was accurately determined with a titration technique. The ion balance of alpine snow has been achieved from those analyses. High alpine snow is slightly acid (H+~ 3 20 μeq 1-1), but is episodically affected by alkaline saharan dust events. The different sources (pollution, seasalt and soil dust) affecting the impurity content of snow were identified using principal component analysis. The measured free acidity, mainly from anthropogenic origin, originates from nitric acid scavenging while sulfuric acidity is partially neutralized by atmospheric ammonia and by alkaline soil dust derived species, the contribution of hydrochloric acid being negligible. All ions exhibit higher concentrations in spring than in winter snow, indicating most likely the influence of increased vertical transport from the lower troposphere at this time. The transport of saharan dust is described through three major events reaching the Alps during March 1990 and 1991. Very high concentrations of Ca2+ and HCO3- were measured in corresponding samples, indicating that

  7. Model of Atmospheric Links on Optical Communications from High Altitude

    NASA Technical Reports Server (NTRS)

    Subich, Christopher

    2004-01-01

    Optical communication links have the potential to solve many of the problems of current radio and microwave links to satellites and high-altitude aircraft. The higher frequency involved in optical systems allows for significantly greater signal bandwidth, and thus information transfer rate, in excess of 10 Gbps, and the highly directional nature of laser-based signals eliminates the need for frequency-division multiplexing seen in radio and microwave links today. The atmosphere, however, distorts an optical signal differently than a microwave signal. While the ionosphere is one of the most significant sources of noise and distortion in a microwave or radio signal, the lower atmosphere affects an optical signal more significantly. Refractive index fluctuations, primarily caused by changes in atmospheric temperature and density, distort the incoming signal in both deterministic and nondeterministic ways. Additionally, suspended particles, such as those in haze or rain, further corrupt the transmitted signal. To model many of the atmospheric effects on the propagating beam, we use simulations based on the beam-propagation method. This method, developed both for simulation of signals in waveguides and propagation in atmospheric turbulence, separates the propagation into a diffraction and refraction problem. The diffraction step is an exact solution, within the limits of numerical precision, to the problem of propagation in free space, and the refraction step models the refractive index variances over a segment of the propagation path. By applying refraction for a segment of the propagation path, then diffracting over that same segment, this method forms a good approximation to true propagation through the atmospheric medium. Iterating over small segments of the total propagation path gives a good approximation to the problem of propagation over the entire path. Parameters in this model, such as initial beam profile and atmospheric constants, are easily modified in a

  8. Exercise economy does not change after acclimatization to moderate to very high altitude.

    PubMed

    Lundby, C; Calbet, J A L; Sander, M; van Hall, G; Mazzeo, R S; Stray-Gundersen, J; Stager, J M; Chapman, R F; Saltin, B; Levine, B D

    2007-06-01

    For more than 60 years, muscle mechanical efficiency has been thought to remain unchanged with acclimatization to high altitude. However, recent work has suggested that muscle mechanical efficiency may in fact be improved upon return from prolonged exposure to high altitude. The purpose of the present work is to resolve this apparent conflict in the literature. In a collaboration between four research centers, we have included data from independent high-altitude studies performed at varying altitudes and including a total of 153 subjects ranging from sea-level (SL) residents to high-altitude natives, and from sedentary to world-class athletes. In study A (n=109), living for 20-22 h/day at 2500 m combined with training between 1250 and 2800 m caused no differences in running economy at fixed speeds despite low typical error measurements. In study B, SL residents (n=8) sojourning for 8 weeks at 4100 m and residents native to this altitude (n=7) performed cycle ergometer exercise in ambient air and in acute normoxia. Muscle oxygen uptake and mechanical efficiency were unchanged between SL and acclimatization and between the two groups. In study C (n=20), during 21 days of exposure to 4300 m altitude, no changes in systemic or leg VO(2) were found during cycle ergometer exercise. However, at the substantially higher altitude of 5260 m decreases in submaximal VO(2) were found in nine subjects with acute hypoxic exposure, as well as after 9 weeks of acclimatization. As VO(2) was already reduced in acute hypoxia this suggests, at least in this condition, that the reduction is not related to anatomical or physiological adaptations to high altitude but to oxygen lack because of severe hypoxia altering substrate utilization. In conclusion, results from several, independent investigations indicate that exercise economy remains unchanged after acclimatization to high altitude.

  9. Stunting and the Prediction of Lung Volumes Among Tibetan Children and Adolescents at High Altitude.

    PubMed

    Weitz, Charles A; Garruto, Ralph M

    2015-12-01

    This study examines the extent to which stunting (height-for-age Z-scores ≤ -2) compromises the use of low altitude prediction equations to gauge the general increase in lung volumes during growth among high altitude populations. The forced vital capacity (FVC) and forced expiratory volume (FEV1) of 208 stunted and 365 non-stunted high-altitude Tibetan children and adolescents between the ages of 6 and 20 years are predicted using the Third National Health and Nutrition Examination Survey (NHANESIII) and the Global Lung Function Initiative (GLF) equations, and compared to observed lung volumes. Stunted Tibetan children show smaller positive deviations from both NHANESIII and GLF prediction equations at most ages than non-stunted children. Deviations from predictions do not correspond to differences in body proportions (sitting heights and chest circumferences relative to stature) between stunted and non-stunted children; but appear compatible with the effects of retarded growth and lung maturation that are likely to exist among stunted children. These results indicate that, before low altitude standards can be used to evaluate the effects of hypoxia, or before high altitude populations can be compared to any other group, it is necessary to assess the relative proportion of stunted children in the samples. If the proportion of stunted children in a high altitude population differs significantly from the proportion in the comparison group, lung function comparisons are unlikely to yield an accurate assessment of the hypoxia effect. The best solution to this problem is to (1) use stature and lung function standards based on the same low altitude population; and (2) assess the hypoxic effect by comparing observed and predicted values among high altitude children whose statures are most like those of children on whom the low altitude spirometric standard is based-preferably high altitude children with HAZ-scores ≥ -1.

  10. Transcriptomic analysis provides insight into high-altitude acclimation in domestic goats.

    PubMed

    Tang, Qianzi; Huang, Wenyao; Guan, Jiuqiang; Jin, Long; Che, Tiandong; Fu, Yuhua; Hu, Yaodong; Tian, Shilin; Wang, Dawei; Jiang, Zhi; Li, Xuewei; Li, Mingzhou

    2015-08-10

    Domestic goats are distributed in a wide range of habitats and have acclimated to their local environmental conditions. To investigate the gene expression changes of goats that are induced by high altitude stress, we performed RNA-seq on 27 samples from the three hypoxia-sensitive tissues (heart, lung, and skeletal muscle) in three indigenous populations from distinct altitudes (600 m, 2000 m, and 3000 m). We generated 129Gb of high-quality sequencing data (~4Gb per sample) and catalogued the expression profiles of 12,421 annotated hircine genes in each sample. The analysis showed global similarities and differences of high-altitude transcriptomes among populations and tissues as well as revealed that the heart underwent the most high-altitude induced expression changes. We identified numerous differentially expressed genes that exhibited distinct expression patterns, and nonsynonymous single nucleotide variant-containing genes that were highly differentiated between the high- and low-altitude populations. These genes have known or potential roles in hypoxia response and were enriched in functional gene categories potentially responsible for high-altitude stress. Therefore, they are appealing candidates for further investigation of the gene expression and associated regulatory mechanisms related to high-altitude acclimation.

  11. On the High- and Low- Altitude Limits of the Auroral Electric Field Region

    NASA Technical Reports Server (NTRS)

    Reiff, P. H.; Lu, G.; Burch, J. L.; Winningham, J. D.; Frank, L. A.; Craven, J. D.; Peterson, W. K.; Heelis, R. A.

    1993-01-01

    Using measurements from the High Altitude Plasma Instrument (HAPI) on the Dynamics-Explorer 1 (DE-1) spacecraft and the Low Altitude Plasma Instrument (LAPI) on Dynamics Explorer 2 (DE 2), we investigate both die high altitude and low altitude extents of the auroral acceleration region. To infer the high altitude limit, we searched the HAPI data base for evidence of upward-directed auroral electric fields located above the spacecraft when the HAPI spacecraft is above 9000 km altitude. We find that such acceleration is common when DE-1 flies through die auroral oval at an altitude of 9,000-11,000 km. At altitudes above 11,000 km, the fraction of the orbits with evidence of at least a 1000 V potential drop above the spacecraft falls, becoming essentially zero above an altitude of 15,000 km. Above that altitude, small (100 V) potential drops are frequently observed, but only rarely are approx. 1 kV potentials observed, typically associated with polar cap or 'theta' arcs or westward traveling surges. To investigate the low-altitude limit of the auroral acceleration region, we use conjunctions of DE 1 and DE 2 along auroral field lines and match the upgoing fluxes of ionospheric ions observed by DE 2 with the flux of accelerated upgoing ions observed at DE 1. Calculating the ionospheric scale height from the ion and electron temperatures and assuming that the parallel flow velocity is independent of height above 800 km, we calculate the altitude at which the upwelling ionospheric ions are effectively completely lost to upward acceleration. The initial lowest-altitude acceleration process could be either a perpendicular acceleration or a parallel electric field, but it must be sufficient to give the entire distribution escape energy. We find that in the two cases studied, near the region of peak auroral potential drop the altitude of this acceleration was around 1700 km (near the O/H neutral crossover altitude), but was significantly higher (approx. 2000 km) near the

  12. On the high- and low-altitude limits of the auroral electric field region

    NASA Astrophysics Data System (ADS)

    Reiff, P. H.; Lu, G.; Burch, J. L.; Winningham, J. D.; Frank, L. A.; Craven, J. D.; Peterson, W. K.; Heelis, R. A.

    Using measurements from the High Altitude Plasma Instrument (HAPI) on the Dynamics-Explorer 1 (DE-1) spacecraft and the Low Altitude Plasma Instrument (LAPI) on Dynamics Explorer 2 (DE 2), we investigate both the high altitude and low altitude extents of the auroral acceleration region. To infer the high altitude limit, we searched the HAPI data base for evidence of upward-directed auroral electric fields located above the spacecraft when the HAPI spacecraft is above 9000 km altitude. We find that such acceleration is common when DE-1 flies through the auroral oval at an altitude of 9,000-11,000 km. At altitudes above 11,000 km, the fraction of the orbits with evidence of at least a 1000 V potential drop above the spacecraft falls, becoming essentially zero above an altitude of 15,000 km. Above that altitude, small (100 V) potential drops are frequently observed, but only rarely are -1 kV potentials observed, typically associated with polar cap or "theta" arcs or westward traveling surges. To investigate the low-altitude limit of the auroral acceleration region, we use conjunctions of DE 1 and DE 2 along auroral field lines and match the upgoing fluxes of ionospheric ions observed by DE 2 with the flux of accelerated upgoing ions observed at DE 1. Calculating the ionospheric scale height from the ion and electron temperatures and assuming that the parallel flow velocity is independent of height above 800 km, we calculate the altitude at which the upwelling ionospheric ions are effectively completely lost to upward acceleration. The initial lowest-altitude acceleration process could be either a perpendicular acceleration or a parallel electric field, but it must be sufficient to give the entire distribution escape energy. We find that in the two cases studied, near the region of peak auroral potential drop the altitude of this acceleration was around 1700 km (near the O/H neutral crossover altitude), but was significantly higher (˜2000 km) near the edges of the arc

  13. Emission characteristics of a heavy-duty diesel engine at simulated high altitudes.

    PubMed

    He, Chao; Ge, Yunshan; Ma, Chaochen; Tan, Jianwei; Liu, Zhihua; Wang, Chu; Yu, Linxiao; Ding, Yan

    2011-08-01

    In order to evaluate the effects of altitude on the pollutant emissions of a diesel engine, an experimental research was carried out using an engine test bench with an altitude simulation system. The emissions of HC, CO, NOx, smoke, and particle number of a heavy-duty diesel engine were measured under steady state operating conditions at sea level and simulated altitudes of 1000 and 2000 m. The experimental results indicate that the high altitude increases the emissions of HC, CO and smoke of the diesel engine, the average increasing rates of which are 30%, 35% and 34% with addition of altitude of 1000 m, respectively. The effect of high altitudes on the NOx emission varies with the engine types and working conditions. At 1000 m the particles number emissions are 1.6 to 4.2 times the levels at the low altitude. The pattern of the particle size distributions at 1000 m is similar with that at sea-level, which is the mono-modal lognormal distribution with geometric mean diameter around 0.1 μm. However, the peak number concentrations of particles are bigger and the exhausted particles are smaller at the high altitude.

  14. Piloted simulation study of a balloon-assisted deployment of an aircraft at high altitude

    NASA Technical Reports Server (NTRS)

    Murray, James; Moes, Timothy; Norlin, Ken; Bauer, Jeffrey; Geenen, Robert; Moulton, Bryan; Hoang, Stephen

    1992-01-01

    A piloted simulation was used to study the feasibility of a balloon assisted deployment of a research aircraft at high altitude. In the simulation study, an unmanned, modified sailplane was carried to 110,000 ft with a high altitude balloon and released in a nose down attitude. A remote pilot controlled the aircraft through a pullout and then executed a zoom climb to a trimmed, 1 g flight condition. A small parachute was used to limit the Mach number during the pullout to avoid adverse transonic effects. The use of small rocket motor was studied for increasing the maximum attainable altitude. Aerodynamic modifications to the basic sailplane included applying supercritical airfoil gloves over the existing wing and tail surfaces. The aerodynamic model of the simulated aircraft was based on low Reynolds number wind tunnel tests and computational techniques, and included large Mach number and Reynolds number effects at high altitude. Parametric variations were performed to study the effects of launch altitude, gross weight, Mach number limit, and parachute size on the maximum attainable stabilized altitude. A test altitude of approx. 95,000 ft was attained, and altitudes in excess of 100,000 ft was attained.

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

    DTIC Science & Technology

    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

  16. Long-Term Health Outcomes in High-Altitude Pulmonary Hypertension.

    PubMed

    Robinson, Jeffrey C; Abbott, Cheryl; Meadows, Christina A; Roach, Robert C; Honigman, Benjamin; Bull, Todd M

    2017-03-01

    Robinson, Jeffrey C., Cheryl Abbott, Christina A. Meadows, Robert C. Roach, Benjamin Honigman, and Todd M. Bull. Long-term health outcomes in high-altitude pulmonary hypertension. High Alt Med Biol. 18:61-66, 2017.

  17. CONDOR: Long endurance high altitude vehicle, volume 5

    NASA Technical Reports Server (NTRS)

    Andrews, L. Cullen; Augsburger, Bill; Cote, Thomas; Ghitea, Mihael; Lee, Il Sik; Lee, Susik; Leong, Gary

    1988-01-01

    The results of a design study resulting in the proposed CONDOR aircraft are presented. The basic requirements are for the aircraft to maintain continuous altitude at or above 45,000 feet for at least a 3-day mission, be able to comfortably support a two-man crew during this period with their field of vision not obstructed to a significant degree, carry a payload of 200 pounds, and provide a power supply to the payload of 2000 watts. The take-off and landing distances must be below 5000. feet, and time to reach cruise altitude must not exceed 3 hours. The subjects discussed are configuration selection, structural analysis, stability and control, crew and payload accomodations, and economic estimates.

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

    NASA Technical Reports Server (NTRS)

    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.

  19. Instantaneous, predictable balloon system descent from high altitude

    NASA Astrophysics Data System (ADS)

    Hazlewood, K.

    The 13 inch diameter helium valve has long been the only method for initiating and controlling balloon system descent. As greater altitudes have become standard, the 13 inch valves have become less and less effective. It takes as long as a half hour or more to effect a noticeable descent, even with two or three valves, at altitudes in excess of 120,000 ft. The project that prompted this study called for a descent rate of >1000 ft/min from 131,000 ft to 60,000 ft. The method by which this was accomplished is presented along with recommendations for future work to provide closer control of rapid descents such as this. The National Center for Atmospheric Research is sponsored by the National Science Foundation. Any opinions, findings, and conclusions or recommendations expressed in this publication are those of the author and do not necessarily reflect the views of the National Science Foundation

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

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

    PubMed

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

    2012-03-01

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

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

    SciTech Connect

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

    2014-01-01

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

  3. High-altitude balloon-launched aircraft - A piloted simulation study

    NASA Technical Reports Server (NTRS)

    Murray, James E.; Moes, Timothy R.; Norlin, Ken

    1993-01-01

    A real-time piloted simulation at the NASA Dryden Flight Research Facility was used to study the feasibility of launching a research aircraft from a high-altitude balloon. In the study, the simulated aircraft was launched in a nosedown attitude at zero airspeed from 110,000 ft. After launch, the pilot flew the aircraft through a near-maximum-lift pullout and then through a zoom climb to a trimmed, l-g flight condition at the test altitude. The study included parametric variations to measure the effects of launch altitude, gross weight, Mach number limit, and parachute size on the test altitude attained. The aerodynamic model of the simulated aircraft was based on flight test results, low Reynolds number windtunnel tests, and computational models; the model included significant Mach number and Reynolds number effects at high altitude. A small parachute was included in the simulation to limit Mach number during the pullout to avoid adverse transonic effects and their resultant energy losses. A small rocket motor was included in the simulation and was investigated for boosting the aircraft to a higher test altitude. In the study, a test altitude of approximately 95,000 ft was attained without rocket boost, and a test altitude in excess of 100,000 ft was attained using small rocket boost.

  4. Effects of acetazolamide on cognitive performance during high-altitude exposure.

    PubMed

    Wang, Jiye; Ke, Tao; Zhang, Xiangnan; Chen, Yaoming; Liu, Mingchao; Chen, Jingyuan; Luo, Wenjing

    2013-01-01

    High-altitude hypoxia impedes cognitive performance. It is not well known whether the prophylactic use of acetazolamide for altitude sickness can influence cognitive performance at high altitude. When ascending to high altitude locations, one may face medical risks, including cognitive impairment, which may significantly hinder climbing abilities or exploratory behavior. Effective prophylactic drugs have rarely been reported. Because acetazolamide is commonly used to treat acute mountain sickness (AMS), we assessed the potential effects of acetazolamide on cognitive performance during high-altitude exposure. Twenty-one volunteers aged 22-26 years were randomized to receive a 4-day treatment of acetazolamide (125 mg Bid, n=11) or placebo (n=10) before and after air travel from Xianyang (402 m) to Lhasa (3561 m). Neuropsychological performance was assessed using the digit symbol substitution test (DSST), paced auditory serial addition test (PASAT), operation span task, and free recall test at 6, 30, and 54 h after arrival at Lhasa. The Lake Louise Score (LLS) was used to diagnose AMS. At high altitude, acetazolamide impaired rather than improved neuropsychological measures of concentration, cognitive processing speed, reaction time, short-term memory, and working memory, which were assessed by DSST, PASAT, and operation span task at 6 and 30 h after arrival (p<0.05). However, the prophylactic use of acetazolamide was found to reduce the incidence of AMS compared to the placebo (p<0.05). In conclusion, acetazolamide impairs neuropsychological function, at least in part, shortly after the ascent to high altitude.

  5. High Altitude Pulmonary Edema in an Experienced Mountaineer. Possible Genetic Predisposition

    PubMed Central

    Whitlow, Kenneth S.; Davis, Babette W.

    2014-01-01

    High altitude pulmonary edema (HAPE) is a form of high altitude illness characterized by cough, dyspnea upon exertion progressing to dyspnea at rest and eventual death, seen in patients who ascend over 2,500 meters, particularly if that ascent is rapid. This case describes a patient with no prior history of HAPE and extensive experience hiking above 2,500 meters who developed progressive dyspnea and cough while ascending to 3,200 meters. His risk factors included rapid ascent, high altitude, male sex, and a possible genetic predisposition for HAPE. PMID:25493133

  6. Domain Specific Changes in Cognition at High Altitude and Its Correlation with Hyperhomocysteinemia

    PubMed Central

    Sharma, Vijay K.; Das, Saroj K.; Dhar, Priyanka; Hota, Kalpana B.; Mahapatra, Bidhu B.; Vashishtha, Vivek; Kumar, Ashish; Hota, Sunil K.; Norboo, Tsering; Srivastava, Ravi B.

    2014-01-01

    Though acute exposure to hypobaric hypoxia is reported to impair cognitive performance, the effects of prolonged exposure on different cognitive domains have been less studied. The present study aimed at investigating the time dependent changes in cognitive performance on prolonged stay at high altitude and its correlation with electroencephalogram (EEG) and plasma homocysteine. The study was conducted on 761 male volunteers of 25–35 years age who had never been to high altitude and baseline data pertaining to domain specific cognitive performance, EEG and homocysteine was acquired at altitude ≤240 m mean sea level (MSL). The volunteers were inducted to an altitude of 4200–4600 m MSL and longitudinal follow-ups were conducted at durations of 03, 12 and 18 months. Neuropsychological assessment was performed for mild cognitive impairment (MCI), attention, information processing rate, visuo-spatial cognition and executive functioning. Total homocysteine (tHcy), vitamin B12 and folic acid were estimated. Mini Mental State Examination (MMSE) showed temporal increase in the percentage prevalence of MCI from 8.17% on 03 months of stay at high altitude to 18.54% on 18 months of stay. Impairment in visuo-spatial executive, attention, delayed recall and procedural memory related cognitive domains were detected following prolonged stay in high altitude. Increase in alpha wave amplitude in the T3, T4 and C3 regions was observed during the follow-ups which was inversely correlated (r = −0.68) to MMSE scores. The tHcy increased proportionately with duration of stay at high altitude and was correlated with MCI. No change in vitamin B12 and folic acid was observed. Our findings suggest that cognitive impairment is progressively associated with duration of stay at high altitude and is correlated with elevated tHcy in the plasma. Moreover, progressive MCI at high altitude occurs despite acclimatization and is independent of vitamin B12 and folic acid. PMID:24988417

  7. Domain specific changes in cognition at high altitude and its correlation with hyperhomocysteinemia.

    PubMed

    Sharma, Vijay K; Das, Saroj K; Dhar, Priyanka; Hota, Kalpana B; Mahapatra, Bidhu B; Vashishtha, Vivek; Kumar, Ashish; Hota, Sunil K; Norboo, Tsering; Srivastava, Ravi B

    2014-01-01

    Though acute exposure to hypobaric hypoxia is reported to impair cognitive performance, the effects of prolonged exposure on different cognitive domains have been less studied. The present study aimed at investigating the time dependent changes in cognitive performance on prolonged stay at high altitude and its correlation with electroencephalogram (EEG) and plasma homocysteine. The study was conducted on 761 male volunteers of 25-35 years age who had never been to high altitude and baseline data pertaining to domain specific cognitive performance, EEG and homocysteine was acquired at altitude ≤240 m mean sea level (MSL). The volunteers were inducted to an altitude of 4200-4600 m MSL and longitudinal follow-ups were conducted at durations of 03, 12 and 18 months. Neuropsychological assessment was performed for mild cognitive impairment (MCI), attention, information processing rate, visuo-spatial cognition and executive functioning. Total homocysteine (tHcy), vitamin B12 and folic acid were estimated. Mini Mental State Examination (MMSE) showed temporal increase in the percentage prevalence of MCI from 8.17% on 03 months of stay at high altitude to 18.54% on 18 months of stay. Impairment in visuo-spatial executive, attention, delayed recall and procedural memory related cognitive domains were detected following prolonged stay in high altitude. Increase in alpha wave amplitude in the T3, T4 and C3 regions was observed during the follow-ups which was inversely correlated (r = -0.68) to MMSE scores. The tHcy increased proportionately with duration of stay at high altitude and was correlated with MCI. No change in vitamin B12 and folic acid was observed. Our findings suggest that cognitive impairment is progressively associated with duration of stay at high altitude and is correlated with elevated tHcy in the plasma. Moreover, progressive MCI at high altitude occurs despite acclimatization and is independent of vitamin B12 and folic acid.

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

    NASA Astrophysics Data System (ADS)

    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

  9. High altitude dives from 7000 to 14,200 feet in the Himalayas.

    PubMed

    Sahni, T K; John, M J; Dhall, A; Chatterjee, A K

    1991-07-01

    Indian Navy divers carried out no-decompression dives at altitudes of 7000 to 14,200 ft (2134-4328 m) in the Nilgiris and Himalayas from May to July 1988. Seventy-eight dives on air and 22 dives on oxygen were carried out at various altitudes. The final dives were at Lake Pangong Tso (4328 m) in Ladakh, Himalayas, to a maximum of 140 feet of sea water (fsw) [42.6 meters of sea water (msw)] equivalent ocean depth in minimum water temperature of 2 degrees C. Oxygen diving at 14,200 ft (4328 m) was not successful. Aspects considered were altitude adaptation, diminished air pressure diving, hypothermia, and remote area survival. Depths at altitude were converted to depths at sea level and were applied to the Royal Navy air tables. Altitude-related manifestations, hypoxia, hypothermia, suspected oxygen toxicity, and equipment failure were observed. It is concluded that stress is due to effects of altitude and cold on man and equipment, as well as changes in diving procedures when diving at high altitudes. Equivalent air depths when applied to Royal Navy tables could be considered a safe method for diving at altitudes.

  10. Metabolic and osmoregulatory function at low and high (3800 m) altitude.

    PubMed

    Greene, H M; Cogger, E A; Miltenberger, T L; Koch, A K; Bray, R E; Wickler, S J

    2002-09-01

    Altitude evokes physiological adjustments that include not only respiratory and cardiovascular properties, but also metabolic function, renal and endocrine responses. The purpose of the present study was designed to expand our understanding of the physiological process involved with acclimatisation to high altitude in equids. The study examined temporal effects on metabolic and osmoregulatory function in horses (n = 6) at rest and postexercise at 3800 m. Animals were studied at 225 m (Pb = 743 mmHg) and during a 10 day stay at altitude (Pb = 487 mmHg). Rest samples were taken 90 min postprandial at 0830 h and immediately after the gallop phase of a standard exercise test. Changes in glucose, insulin, cortisol, thyroxine, sodium, potassium, chloride and total protein were assessed at both altitudes. Exercise stimulated increases in cortisol, thyroxine, potassium, and chloride; while the concentrations of glucose, insulin, sodium and total protein (regardless of altitude) decreased. Acute (Day 2) altitude exposure (following transport stress) produced significant increases in glucose, cortisol, thyroxine, chloride and protein at rest and exercise. All variables (except cortisol) appeared to stabilise by Day 4 of altitude exposure. Observations from these data (coupled with haematological and blood gases data) indicate that equids acutely acclimate within 2-3 days to this altitude.

  11. Evaluating the Risks of High Altitude Travel in Chronic Liver Disease Patients.

    PubMed

    Luks, Andrew M; Swenson, Erik R

    2015-06-01

    Luks, Andrew M., and Erik R. Swenson. Clinician's Corner: Evaluating the risks of high altitude travel in chronic liver disease patients. High Alt Med Biol 16:80-88, 2015.--With improvements in the quality of health care, people with chronic medical conditions are experiencing better quality of life and increasingly participating in a wider array of activities, including travel to high altitude. Whenever people with chronic diseases travel to this environment, it is important to consider whether the physiologic responses to hypobaric hypoxia will interact with the underlying medical condition such that the risk of acute altitude illness is increased or the medical condition itself may worsen. This review considers these questions as they pertain to patients with chronic liver disease. While the limited available evidence suggests there is no evidence of liver injury or dysfunction in normal individuals traveling as high as 5000 m, there is reason to suspect that two groups of cirrhosis patients are at increased risk for problems, hepatopulmonary syndrome patients, who are at risk for severe hypoxemia following ascent, and portopulmonary hypertension patients who may be at risk for high altitude pulmonary edema and acute right ventricular dysfunction. While liver transplant patients may tolerate high altitude exposure without difficulty, no information is available regarding the risks of long-term residence at altitude with chronic liver disease. All travelers with cirrhosis require careful pre-travel evaluation to identify conditions that might predispose to problems at altitude and develop risk mitigation strategies for these issues. Patients also require detailed counseling about recognition, prevention, and treatment of acute altitude illness and may require different medication regimens to prevent or treat altitude illness than used in healthy individuals.

  12. [High frequency of dyslipidemia and impaired fasting glycemia in a high altitude Peruvian population].

    PubMed

    Málaga, Germán; Zevallos-Palacios, Claudia; Lazo, María de los Ángeles; Huayanay, Carlos

    2010-01-01

    We performed a cross sectional study in Lari (3600 m), a highland rural community from Arequipa, Peru. We evaluated a body mass index (BMI), glycemia and lipid profile in 74 over 18 year persons. The mean age was 51.7 ± 18.0 years, 62.2% were women, mean of BMI was 25.6 ± 3.7. Prevalence of hypercholesterolemia was 40.6%, "low HDL" in 77% of the population (93.5% in women vs 50% in men, p <0.001) and elevated level of LDL was 71.7%. The prevalence of impaired fasting glycemia was 27%. In conclusion, we found high prevalence of impaired fasting glycemia, hypercholesterolemia and especially "low HDL" in high altitude rural natives. These findings must be considered to realize interventions in high altitude populations to avoid future cardiovascular complications.

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

    PubMed Central

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

    2015-01-01

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

  14. Cardiovascular effects of chronic carbon monoxide and high-altitude exposure

    SciTech Connect

    McGrath, J.J. )

    1989-07-01

    At higher altitudes, ambient carbon monoxide levels are increasing with the number of residents and tourists and their use of motor vehicles and heating devices (such as fireplaces, furnaces, and stoves). Although chronic exposure to carbon monoxide or high altitude causes pronounced cardiovascular changes in humans as well as in animals, there is little information on the effects elicited by these stressors combined. Data from acute studies and theoretical considerations suggest that carbon monoxide inhaled at altitude may be more detrimental than carbon monoxide inhaled at sea level. It is not known, however, if the cardiovascular system adapts or deteriorates with continuous, concurrent exposure to carbon monoxide and high altitude. Male laboratory rats were exposed for six weeks in steel barometric chambers to altitudes ranging from 3,300 ft (ambient) to 18,000 ft and to concentrations ranging from 0 to 500 parts per million (ppm)2. Carbon monoxide had no effect on body weight at any altitude. There was a tendency for hematocrit to increase even at the lowest concentration of carbon monoxide (9 ppm), but the increase did not become significant until 100 ppm. At 10,000 ft, there was a tendency for total heart weight to increase in rats inhaling 100 ppm carbon monoxide. Although its effects on the heart at altitude are complex, carbon monoxide, in concentrations of 500 ppm or less, had little effect on the right ventricle; it did not exacerbate any effects due to altitude. There was a tendency for the left ventricle weight to increase with exposure to 35 ppm carbon monoxide at altitude, but the increase was not significant until 100 ppm carbon monoxide. Heart rate, blood pressure, cardiac output, and peripheral resistance were unaffected by exposure to 35 ppm carbon monoxide or 10,000-ft altitude singly or in combination.

  15. Metabolic Characteristics and Response to High Altitude in Phrynocephalus erythrurus (Lacertilia: Agamidae), a Lizard Dwell at Altitudes Higher Than Any Other Living Lizards in the World

    PubMed Central

    Tang, Xiaolong; Xin, Ying; Wang, Huihui; Li, Weixin; Zhang, Yang; Liang, Shiwei; He, Jianzheng; Wang, Ningbo; Ma, Ming; Chen, Qiang

    2013-01-01

    Metabolic response to high altitude remains poorly explored in reptiles. In the present study, the metabolic characteristics of Phrynocephaluserythrurus (Lacertilia: Agamidae), which inhabits high altitudes (4500 m) and Phrynocephalusprzewalskii (Lacertilia: Agamidae), which inhabits low altitudes, were analysed to explore the metabolic regulatory strategies for lizards living at high-altitude environments. The results indicated that the mitochondrial respiratory rates of P. erythrurus were significantly lower than those of P. przewalskii, and that proton leak accounts for 74~79% of state 4 and 7~8% of state3 in P. erythrurus vs. 43~48% of state 4 and 24~26% of state3 in P. przewalskii. Lactate dehydrogenase (LDH) activity in P. erythrurus was lower than in P. przewalskii, indicating that at high altitude the former does not, relatively, have a greater reliance on anaerobic metabolism. A higher activity related to β-hydroxyacyl coenzyme A dehydrogenase (HOAD) and the HOAD/citrate synthase (CS) ratio suggested there was a possible higher utilization of fat in P. erythrurus. The lower expression of PGC-1α and PPAR-γ in P. erythrurus suggested their expression was not influenced by cold and low PO2 at high altitude. These distinct characteristics of P. erythrurus are considered to be necessary strategies in metabolic regulation for living at high altitude and may effectively compensate for the negative influence of cold and low PO2. PMID:23951275

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

    PubMed

    Tang, Xiaolong; Xin, Ying; Wang, Huihui; Li, Weixin; Zhang, Yang; Liang, Shiwei; He, Jianzheng; Wang, Ningbo; Ma, Ming; Chen, Qiang

    2013-01-01

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

  17. Flow separation in rocket nozzles under high altitude condition

    NASA Astrophysics Data System (ADS)

    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.

  18. Rummy high-altitude pressure measurements and analysis

    SciTech Connect

    Banister, J.R.; Hereford, W.V.

    1982-01-01

    Five pressure-measurement canisters equipped with parachutes were deployed from an A7C aircraft on the Rummy test. Their altitudes above Yucca flat were over 8.5 km when the pressure pulse arrived. Three successful measurements were obtained. These time histories showed a more complicated behavior than histories obtained on Pahute Mesa tests because the Rummy event developed double spall closures over a large area. Excellent agreement was obtained between the observed pressure histories and those calculated from surface acceleration measurements. The Yucca Flat terrain was so level that pressure pulses were not appreciably changed or weakened by elevation differences.

  19. High-altitude incoherent-scatter measurements at Jicamarca

    NASA Astrophysics Data System (ADS)

    Hysell, D. L.; Milla, M. A.; Woodman, R. F.

    2017-02-01

    In an attempt to reproduce experimental results obtained in the early days of operations, electron density profiles have been measured at the Jicamarca Radio Observatory at altitudes reaching L=2. The methodology involves using a combination of pulses, including pulses as long as 4 ms, and processing the data with matched filtering. The modern experiments are complicated by systemic, time-dependent bias in the noise estimators as well as by clutter from satellites and space debris, including a geosynchronous satellite. Ultimately, experiment performance comparable to what was achieved in the original experiments could be achieved and should be surpassed in future experiments when all four of the Jicamarca transmitters will be utilized.

  20. High rate of schistosomiasis in travelers after a brief exposure to the high-altitude Nyinambuga crater lake, Uganda.

    PubMed

    Lachish, Tamar; Tandlich, Moshik; Grossman, Tamar; Schwartz, Eli

    2013-11-01

    Travel-related schistosomiasis is usually associated with prolonged freshwater exposure. Until recently, Uganda's crater lakes were considered schistosomiasis free due to their high-altitude location. We describe an outbreak of acute schistosomiasis after a brief exposure (mean, 22 ± 9.5 minutes) to a high-altitude crater lake.

  1. On the Survival of High-altitude Open Clusters within the Milky Way Galaxy Tides

    NASA Astrophysics Data System (ADS)

    Martinez-Medina, L. A.; Pichardo, B.; Peimbert, A.; Moreno, E.

    2017-01-01

    It is a common assumption that high-altitude open clusters live longer compared to clusters moving close to the Galactic plane. This is because, at high altitudes, open clusters are far from the disruptive effects of in-plane substructures, such as spiral arms, molecular clouds, and the bar. However, an important aspect to consider in this scenario is that orbits of high-altitude open clusters will eventually cross the Galactic plane, where the vertical tidal field of the disk is strong. In this work, we simulate the interaction of open clusters with the tidal field of a detailed Milky Way Galactic model at different average altitudes and galactocentric radii. We find that the life expectancy of clusters decreases as the maximum orbital altitude increases and reaches a minimum at altitudes of approximately 600 pc. Clusters near the Galactic plane live longer because they do not experience strong vertical tidal shocks from the Galactic disk; then, for orbital altitudes higher than 600 pc, clusters again start to live longer due to the decrease in the number of encounters with the disk. With our study, we find that the compressive nature of the tides in the arms region and the bar play an important role in the survival of small clusters by protecting them from disruption: clusters inside the arms can live up to twice as long as those outside the arms at similar galactocentric distances.

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

    PubMed Central

    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

  3. Dual Wavelength Lidar Observation of Tropical High-Altitude Cirrus Clouds During the ALBATROSS 1996 Campaign

    NASA Technical Reports Server (NTRS)

    Beyerle, G.; Schafer, J.; Neuber, R.; Schrems, O.; McDermid, I. S.

    1998-01-01

    Dual wavelength aerosol lidar observations of tropical high-altitude cirrus clouds were performed during the ALBATROSS 1996 campaign aboard the research vessel POLARSTERN on the Atlantic ocean in October-November 1996.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    Hoffman, Julien I E

    2016-06-01

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

  6. The physiological effects of resveratrol and its potential application in high altitude medicine.

    PubMed

    Zhu, Hui-li; Nie, Hong-jing; Li, Pei-bing; Deng, Bing-nan; Duan, Rui-feng; Jin, Hong; Chen, Zhao-li

    2015-11-01

    Resveratrol, as a natural polyphenolic compound, has a wide range of beneficial effects, which includes anti-tumor, cardiovascular protection, anti-oxidant and estrogen-like effects, and so on. Its various physiological properties are closely related to the therapeutic principle for prevention and treatment of high altitude hypoxia injury. Resveratrol may play an important role in relieving or curing high altitude diseases, especially high altitude polycythemia(HAPC). However, the literature about study and application of resveratrol in plateau medicine field is rarely reported up to now. In this review, we summarized the physiological effects of resveratrol, discussed the possible main principle of resveratrol for HAPC therapy, and looked forward to resveratrol's perspective or potential application in high altitude medicine.

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

    PubMed

    Naeije, R; Huez, S; Lamotte, M; Retailleau, K; Neupane, S; Abramowicz, D; Faoro, V

    2010-11-01

    Altitude exposure is associated with decreased exercise capacity and increased pulmonary vascular resistance (PVR). Echocardiographic measurements of pulmonary haemodynamics and a cardiopulmonary exercise test were performed in 13 healthy subjects at sea level, in normoxia and during acute hypoxic breathing (1 h, 12% oxygen in nitrogen), and in 22 healthy subjects after acclimatisation to an altitude of 5,050 m. The measurements were obtained after randomisation, double-blinded to the intake of placebo or the endothelin A receptor blocker sitaxsentan (100 mg·day(-1) for 7 days). Blood and urine were sampled for renal function measurements. Normobaric as well as hypobaric hypoxia increased PVR and decreased maximum workload and oxygen uptake (V'(O(2),max)). Sitaxsentan decreased PVR in acute and chronic hypoxia (both p<0.001), and partly restored V'(O(2),max), by 30 % in acute hypoxia (p<0.001) and 10% in chronic hypoxia (p<0.05). Sitaxsentan-induced changes in PVR and V'(O(2),max) were correlated (p = 0.01). Hypoxia decreased glomerular filtration rate and free water clearance, and increased fractional sodium excretion. These indices of renal function were unaffected by sitaxsentan intake. Selective endothelin A receptor blockade with sitaxsentan improves mild pulmonary hypertension and restores exercise capacity without adverse effects on renal function in hypoxic normal subjects.

  8. Initial feasibility study of a microwave-powered sailplane as a high-altitude observation platform

    NASA Technical Reports Server (NTRS)

    Heyson, H. H.

    1978-01-01

    It is shown that a microwave-powered sailplane can be a reasonable substitute for a satellite in some missions requiring only limited coverage of the surface of the earth. A mode of operation in which the aircraft cyclically climbs to high altitude in the beam, and then glides for several hundred kilometers, is feasible and takes advantage of the inherent forward speed of the sailplane at high altitude.

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

    NASA Technical Reports Server (NTRS)

    Noack, W G

    1920-01-01

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

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

    PubMed Central

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

    2010-01-01

    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. PMID:21112992

  11. Tracking performance with two breathing oxygen concentrations after high altitude rapid decompression

    NASA Technical Reports Server (NTRS)

    Nesthus, Thomas E.; Schiflett, Samuel G.; Oakley, Carolyn J.

    1992-01-01

    Current military aircraft Liquid Oxygen (LOX) systems supply 99.5 pct. gaseous Aviator's Breathing Oxygen (ABO) to aircrew. Newer Molecular Sieve Oxygen Generation Systems (MSOGS) supply breathing gas concentration of 93 to 95 pct. O2. The margin is compared of hypoxia protection afforded by ABO and MSOGS breathing gas after a 5 psi differential rapid decompression (RD) in a hypobaric research chamber. The barometric pressures equivalent to the altitudes of 46000, 52000, 56000, and 60000 ft were achieved from respective base altitudes in 1 to 1.5 s decompressions. During each exposure, subjects remained at the simulated peak altitude breathing either 100 or 94 pct. O2 with positive pressure for 60 s, followed by a rapid descent to 40000 ft. Subjects used the Tactical Life Support System (TLSS) for high altitude protection. Subcritical tracking task performance on the Performance Evaluation Device (PED) provided psychomotor test measures. Overall tracking task performance results showed no differences between the MSOGS breathing O2 concentration of 94 pct. and ABO. Significance RMS error differences were found between the ground level and base altitude trials compared to peak altitude trials. The high positive breathing pressures occurring at the peak altitudes explained the differences.

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

    NASA Technical Reports Server (NTRS)

    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.

  13. Plasma and electric field boundaries at high and low altitudes on July 29, 1977

    NASA Technical Reports Server (NTRS)

    Fennell, J. F.; Johnson, R. G.; Young, D. T.; Torbert, R. B.; Moore, T. E.

    1982-01-01

    Hot plasma observations at high and low altitudes were compared. The plasma ion composition at high altitudes outside the plasmasphere was 0+. Heavy ions were also observed at low altitudes outside the plasmasphere. It is shown that at times these ions are found well below the plasmapause inside the plasmasphere. Comparisons of the low altitude plasma and dc electric fields show that the outer limits of the plasmasphere is not always corotating at the low L-shells. The corotation boundary, the estimated plasmapause boundary at the boundary of the inner edge of plasma sheet ions were at the same position. The inner edge of plasma sheet electrons is observed at higher latitudes than the plasmasphere boundary during disturbed times. The inner edge of the plasma sheaths shows a strong dawn to dusk asymmetry. At the same time the inner edge of the ring current and plasma sheath also moves to high latitudes reflecting an apparent inflation of the magnetosphere.

  14. King of the mountains: Tibetan and Sherpa physiological adaptations for life at high altitude.

    PubMed

    Gilbert-Kawai, Edward T; Milledge, James S; Grocott, Michael P W; Martin, Daniel S

    2014-11-01

    Anecdotal evidence surrounding Tibetans' and Sherpas' exceptional tolerance to hypobaric hypoxia has been recorded since the beginning of high-altitude exploration. These populations have successfully lived and reproduced at high altitude for hundreds of generations with hypoxia as a constant evolutionary pressure. Consequently, they are likely to have undergone natural selection toward a genotype (and phenotype) tending to offer beneficial adaptation to sustained hypoxia. With the advent of translational human hypoxic research, in which genotype/phenotype studies of healthy individuals at high altitude may be of benefit to hypoxemic critically ill patients in a hospital setting, high-altitude natives may provide a valuable and intriguing model. The aim of this review is to provide a comprehensive summary of the scientific literature encompassing Tibetan and Sherpa physiological adaptations to a high-altitude residence. The review demonstrates the extent to which evolutionary pressure has refined the physiology of this high-altitude population. Furthermore, although many physiological differences between highlanders and lowlanders have been found, it also suggests many more potential avenues of investigation.

  15. High Altitude, Continuous Positive Airway Pressure, and Obstructive Sleep Apnea: Subjective Observations and Objective Data

    PubMed Central

    Malhotra, Atul; Schwartz, Eli

    2013-01-01

    Abstract Ginosar, Yehuda, Atul Malhotra, and Eli Schwartz. High altitude, continuous positive airway pressure, and obstructive sleep apnea: Subjective observations and objective data. High Alt Med Biol 14:186–189, 2013.—We report observations made by one of the authors who ascended to the Thorang La pass (5416 m) in the Nepal Himalaya in October 2010, despite moderate-severe obstructive sleep apnea. We report the first recorded use of nasal CPAP to treat high altitude pulmonary edema (progressively severe dyspnea at rest and severe orthopnea, with tachycardia and tachypnea) that occurred at 4400 meters, when snow and darkness made safe evacuation difficult. We also present objective longitudinal data of the effects of altitude on auto-adjusting CPAP delivered via a portable nasal CPAP device, and on the apnea hypopnea index measured during sleep while using the device. OSA may be a risk factor for the development of high altitude pulmonary edema and we suggest that a nasal CPAP device located in high altitude trekking stations may provide an additional or alternative treatment option for managing high altitude pulmonary edema until evacuation is possible. PMID:23795742

  16. Podophyllum hexandrum-Mediated Survival Protection and Restoration of Other Cellular Injuries in Lethally Irradiated Mice

    PubMed Central

    Sankhwar, Sanghmitra; Gupta, Manju Lata; Gupta, Vanita; Verma, Savita; Suri, Krishna Avtar; Devi, Memita; Sharma, Punita; Khan, Ehsan Ahmed; Alam, M. Sarwar

    2011-01-01

    This study aims at the development of a safe and effective formulation to counter the effects of lethal irradiation. The sub-fraction (G-001M), prepared from Podophyllum hexandrum has rendered high degree of survival (>90%) at a dose of 6 mg kg−1 body weight (intramuscular) in lethally irradiated mice. Therapeutic dose of G-001M, at about 20 times lower concentration than its LD100, has revealed a DRF of 1.62. Comet assay studies in peripheral blood leukocytes have reflected that, treatment of G-001M before irradiation has significantly reduced DNA tail length (P < .001) and DNA damage score (P < .001), as compared to radiation-only group. Spleen cell counts in irradiated animals had declined drastically at the very first day of exposure, and the fall continued till the 5th day (P < .001). In the treated irradiated groups, there was a steep reduction in the counts initially, but this phase did not prolong. More than 60% decline in thymocytes of irradiated group animals was registered at 5 h of irradiation when compared with controls, and the fall progressed further downwards with the similar pace till 5th day of exposure (P < .001). At later intervals, thymus was found fully regressed. In G-001M pre-treated irradiated groups also, thymocytes decreased till the 5th day but thereafter rejuvenated and within 30 days of treatment the values were close to normal. Current studies have explicitly indicated that, G-001M in very small doses has not only rendered high survivability in lethally irradiated mice, but also protected their cellular DNA, besides supporting fast replenishment of the immune system. PMID:19553386

  17. [Pulmonary hemodynamics and hemostasis in rabbits exposed to high altitude].

    PubMed

    Almerekova, A A; Tartakovskiĭ, V N; Isakova, Zh T

    1993-01-01

    Pulmonary hemodynamics, homeostasis and red blood parameters were studied in 77 rabbits in the mountains of the Tien Shan (3200 m above sea-level). Exposure of animals in alpine environment gave rise to pulmonary hypertension, polycythemia, alterations of homeostasis by the pattern of hyper- and hypocoagulation syndrome. On certain stages of adaptation products of paracoagulation were observed in blood as well as intravascular aggregation of formed elements, increased sensitivity of blood plates to platelet activation, increased fibrinolysis. Given existing hypothesis about involvement of changes in homeostasis and red blood in the pathogenesis of altitude pulmonary hypertension, the coefficients of paired linear correlation between indices of pulmonary hemodynamics and blood have been calculated. These coefficients are valid only for low values of the ratio.

  18. High-Altitude Air Mass Zero Calibration of Solar Cells

    NASA Technical Reports Server (NTRS)

    Woodyard, James R.; Snyder, David B.

    2005-01-01

    Air mass zero calibration of solar cells has been carried out for several years by NASA Glenn Research Center using a Lear-25 aircraft and Langley plots. The calibration flights are carried out during early fall and late winter when the tropopause is at the lowest altitude. Measurements are made starting at about 50,000 feet and continue down to the tropopause. A joint NASA/Wayne State University program called Suntracker is underway to explore the use of weather balloon and communication technologies to characterize solar cells at elevations up to about 100 kft. The balloon flights are low-cost and can be carried out any time of the year. AMO solar cell characterization employing the mountaintop, aircraft and balloon methods are reviewed. Results of cell characterization with the Suntracker are reported and compared with the NASA Glenn Research Center aircraft method.

  19. Scattering of terrestrial kilometric radiation at very high altitudes

    NASA Technical Reports Server (NTRS)

    Alexander, J. K.; Kaiser, M. L.; Rodriguez, P.

    1978-01-01

    On a number of occasions during the 3.8 yr. operating lifetime of RAE-2, strong terrestrial kilometric radiation was observed when the spacecraft was over the far side of the moon and when the low altitude terrestrial magnetosphere was completely obscured from view. If these deep lunar occultation events are used to infer radio source locations, then it is found that the apparent source must sometimes be situated at geocentric distances of 10 to 40 sub E or more. From an analysis of these events, it is shown that they are probably due to propagation effects rather than the actual generation of the emission at such large distances. The kilometric radiation can be generated near the earth at auroral latitudes and subsequently strongly scattered in the magnetosheath and nearby solar wind to produce the large apparent distances. The most likely scatterers are density inhomogeneities in the magnetosheath plasma and ion plasma waves in the magnetosheath and the upstream solar wind.

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

    PubMed Central

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

    2016-01-01

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

  1. Remote ischemic preconditioning for prevention of high-altitude diseases: fact or fiction?

    PubMed

    Berger, Marc Moritz; Macholz, Franziska; Mairbäurl, Heimo; Bärtsch, Peter

    2015-11-15

    Preconditioning refers to exposure to brief episodes of potentially adverse stimuli and protects against injury during subsequent exposures. This was first described in the heart, where episodes of ischemia/reperfusion render the myocardium resistant to subsequent ischemic injury, which is likely caused by reactive oxygen species (ROS) and proinflammatory processes. Protection of the heart was also found when preconditioning was performed in an organ different from the target, which is called remote ischemic preconditioning (RIPC). The mechanisms causing protection seem to include stimulation of nitric oxide (NO) synthase, increase in antioxidant enzymes, and downregulation of proinflammatory cytokines. These pathways are also thought to play a role in high-altitude diseases: high-altitude pulmonary edema (HAPE) is associated with decreased bioavailability of NO and increased generation of ROS, whereas mechanisms causing acute mountain sickness (AMS) and high-altitude cerebral edema (HACE) seem to involve cytotoxic effects by ROS and inflammation. Based on these apparent similarities between ischemic damage and AMS, HACE, and HAPE, it is reasonable to assume that RIPC might be protective and improve altitude tolerance. In studies addressing high-altitude/hypoxia tolerance, RIPC has been shown to decrease pulmonary arterial systolic pressure in normobaric hypoxia (13% O2) and at high altitude (4,342 m). Our own results indicate that RIPC transiently decreases the severity of AMS at 12% O2. Thus preliminary studies show some benefit, but clearly, further experiments to establish the efficacy and potential mechanism of RIPC are needed.

  2. Cardiovascular effects of chronic carbon monoxide and high-altitude exposure.

    PubMed

    McGrath, J J

    1989-07-01

    At higher altitudes, ambient carbon monoxide levels are increasing with the number of residents and tourists and their use of motor vehicles and heating devices (such as fireplaces, furnaces, and stoves). Although chronic exposure to carbon monoxide or high altitude causes pronounced cardiovascular changes in humans as well as in animals, there is little information on the effects elicited by these stressors combined. Data from acute studies and theoretical considerations suggest that carbon monoxide inhaled at altitude may be more detrimental than carbon monoxide inhaled at sea level. It is not known, however, if the cardiovascular system adapts or deteriorates with continuous, concurrent exposure to carbon monoxide and high altitude. Male laboratory rats were exposed for six weeks in steel barometric chambers to altitudes ranging from 3,300 ft (ambient) to 18,000 ft and to concentrations ranging from 0 to 500 parts per million (ppm)2. Carbon monoxide had no effect on body weight at any altitude. There was a tendency for hematocrit to increase even at the lowest concentration of carbon monoxide (9 ppm), but the increase did not become significant until 100 ppm. At 10,000 ft, there was a tendency for total heart weight to increase in rats inhaling 100 ppm carbon monoxide. Although its effects on the heart at altitude are complex, carbon monoxide, in concentrations of 500 ppm or less, had little effect on the right ventricle; it did not exacerbate any effects due to altitude. There was a tendency for the left ventricle weight to increase with exposure to 35 ppm carbon monoxide at altitude, but the increase was not significant until 100 ppm carbon monoxide. Heart rate, blood pressure, cardiac output, and peripheral resistance were unaffected by exposure to 35 ppm carbon monoxide or 10,000-ft altitude singly or in combination. I conclude that six weeks of exposure to 35 ppm carbon monoxide does not produce measurable effects in the healthy laboratory rat, nor does it

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

    NASA Technical Reports Server (NTRS)

    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.

  4. High-Altitude Flight Cooling Investigation of a Radial Air-Cooled Engine

    NASA Technical Reports Server (NTRS)

    Manganiello, Eugene J; Valerino, Michael F; Bell, E Barton

    1947-01-01

    An investigation of the cooling of an 18-cylinder, twin-row, radial, air-cooled engine in a high-performance pursuit airplane has been conducted for variable engine and flight conditions at altitudes ranging from 5000 to 35,000 feet in order to provide a basis for predicting high-altitude cooling performance from sea-level or low altitude experimental results. The engine cooling data obtained were analyzed by the usual NACA cooling-correlation method wherein cylinder-head and cylinder-barrel temperatures are related to the pertinent engine and cooling-air variables. A theoretical analysis was made of the effect on engine cooling of the change of density of the cooling air across the engine (the compressibility effect), which becomes of increasing importance as altitude is increased. Good agreement was obtained between the results of the theoretical analysis and the experimental data.

  5. Proteins differentially expressed in elicited cell suspension culture of Podophyllum hexandrum with enhanced podophyllotoxin content

    PubMed Central

    2012-01-01

    Background Podophyllotoxin (PTOX), the precursor for semi-synthesis of cancer therapeutics like etoposide, teniposide and etophos, is primarily obtained from an endangered medicinal herb, Podophyllum hexandrum Royle. PTOX, a lignan is biosynthetically derived from the phenylpropanoid pathway. The aim of this study is to investigate changes in the P. hexandrum cell proteome potentially related to PTOX accumulation in response to methyl jasmonate (MeJA) elicitation. High-resolution two-dimensional gel electrophoresis (2-DE) followed by colloidal Coomassie staining and mass spectrometric analysis was used to detect statistically significant changes in cell’s proteome. Result The HPLC analysis showed approximately 7–8 fold change in accumulation of PTOX, in the 12day old cell suspension culture (i.e. after 9days of elicitation) elicited with 100 μM MeJA as compared to the control. Using 2-DE a total of 233 spots was detected, out of which 105 spots were identified by MALDI TOF-TOF MS/MS. Data were subjected to functional annotation from a biological point of view through KEGG. The phenylpropanoid and monolignol pathway enzymes were identified, amongst these, chalcone synthase, polyphenol oxidase, caffeoyl CoA 3-O-methyltransferase, S-adenosyl-L-methionine-dependent methyltransferases, caffeic acid-O-methyl transferase etc. are noted as important. The relation of other differentially accumulated proteins with varied effects caused by elicitors on P. hexandrum cells namely stress and defense related protein, transcription and DNA replication and signaling are also discussed. Conclusions Elicitor-induced PTOX accumulation in P. hexandrum cell cultures provides a responsive model system to profile modulations in proteins related to phenylpropanoid/monolignol biosynthesis and other defense responses. Present findings form a baseline for future investigation on a non-sequenced medicinal herb P. hexandrum at molecular level. PMID:22621772

  6. Propranolol and the Compensatory Circulatory Responses to Orthostasis at High Altitude,

    DTIC Science & Technology

    1988-03-14

    cardiac output during orthostasis at high altitude. This study was undertaken to determine if tachycardia, mediated by beta-adrenergic sympathetic...1988). The approach used in the present study was to administer propranolol, a beta-adrenergic blocking agent, to healthy subjects going from sea...heart rate, upright tilt would be less tolerated at altitude. This study also provided the opportunity to describe for the first time, the effects of

  7. Effect of Propranolol on Metabolic Responses to Exercise at High Altitude

    DTIC Science & Technology

    1988-02-01

    or in glycolytic or oxidative skeletal muscle enzyme activity (30) 4 during the period of altitude acclimatization. The glycogen sparing adaptation...Sympathetic nervous activity is known to be increased at high altitude (14). The purpose of the present investigation was to test the hypothesis that chronic...divided into several pieces, cleaned of blood and connective tissue, and the weight of each piece, corrected for water evaporation (7). was determined

  8. High Altitude Neutral Particle Transport Using the Monte Carlo Simulation Code MCNP with Variable Density Atmosphere

    DTIC Science & Technology

    1991-03-01

    Monti Captain# USAF AFIT.’GNE/F•P/91M-6 (LO IA Approved for public release; distribution unlimited AFIT/IGNE/ENP/91M-6 HIGH ALTITUDE NEUTRAL... distribution unlimited Preface The purpose of this study was to perform Monte Carlo simulations of neutral particle transport with primary and secondary...21 4. Spatial Cell Geometry for Co-Altitude Detectors .................... .................. 44 5. MCNP vs. SMAUG Neutron Fluence at Source Co

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

    PubMed Central

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

    2015-01-01

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

  10. High Altitude Small Engine Test Techniques at the NASA Glenn Propulsion Systems Lab

    NASA Technical Reports Server (NTRS)

    Castner, Raymond; Wyzykowski, John; Chiapetta, Santo

    2001-01-01

    A High Altitude Test was performed in the Propulsion Systems Lab (PSL) at the NASA Glenn Research Center using a Pratt and Whitney Canada PW545 jet engine. This engine was tested to develop a highaltitude database on small, high-bypass ratio, engine performance and operability. Industry is interested in the use of high-bypass engines for Uninhabited Aerial Vehicles (UAV's) to perform high altitude surveillance. The tests were a combined effort between Pratt & Whitney Canada (PWC) and NASA Glenn Research Center. A large portion of this test activity was to collect performance data with a highly instrumented low-pressure turbine. Low-pressure turbine aerodynamic performance at low Reynolds numbers was collected and compared to analytical models developed by NASA and PWC. This report describes the test techniques implemented to obtain high accuracy turbine performance data in an altitude test facility, including high accuracy airflow at high altitudes, very low mass flow, and low air temperatures. Major accomplishments from this test activity were to collect accurate and repeatable turbine performance data at high altitudes to within 1 percent. Data were collected at 19,800m, 16,750m, and 13,700m providing documentation of diminishing LPT performance with reductions in Reynolds number in an actual engine flight environment. The test provided a unique database for the development of engine analysis codes to be used for future LPT performance improvements.

  11. UVER and UV index at high altitude in Northwestern Argentina.

    PubMed

    Utrillas, M P; Marín, M J; Esteve, A R; Salazar, G; Suarez, H; Castillo, J; Martínez-Lozano, J A

    2016-10-01

    Measurements of ultraviolet erythemal radiation (UVER) made during two years at three sites located at altitudes over 1000ma.s.l. in Northwestern Argentina (Salta, San Carlos, and El Rosal) have been used to estimate and analyze the UV Index (UVI) and the cumulative doses at these locations. For the UVER irradiance, data of January (maximum values) and June (minimum values) have been analyzed as representative of the year for all locations. The UVI reaches extreme (>11) values in >20% of the analyzed days in Salta (1190ma.s.l.), while these are reached in San Carlos (1611ma.s.l.) and El Rosal (3355ma.s.l.) in >40% of the analyzed days. Finally, the cumulative doses over an average year have also been studied for each location. The doses received during austral summer and autumn are of the same order, and represent one third of the annual dose, while the doses received during austral winter and spring represent one sixth of the annual dose approximately.

  12. Flight test evaluation of an RAF high altitude partial pressure protective assembly

    NASA Technical Reports Server (NTRS)

    Ashworth, G. R.; Putnam, T. W.; Dana, W. J.; Enevoldson, E. K.; Winter, W. R.

    1979-01-01

    A partial pressure suit was evaluated during tests in an F-104 and F-15 as a protective garment for emergency descents. The garment is an pressure jerkin and modified anti-g suit combined with an oronasal mask. The garment can be donned and doffed at the aircraft to minimize thermal buildup. The oronasal mask was favored by the pilots due to its immobility on the face during high g-loading. The garment was chosen to provide optimum dexterity for the pilot, which is not available in a full pressure suit, while protecting the pilot at altitudes up to 18,288 meters, during a cabin decompression, and subsequent aircraft descent. During cabin decompressions in the F-104 and F-15, cabin pressure altitude was measured at various aircraft angles of attack, Mach numbers, and altitudes to determine the effect of the aerodynamic slipstream on the cabin altitude.

  13. Heart rate and respiratory rhythm dynamics on ascent to high altitude

    NASA Technical Reports Server (NTRS)

    Lipsitz, L. A.; Hashimoto, F.; Lubowsky, L. P.; Mietus, J.; Moody, G. B.; Appenzeller, O.; Goldberger, A. L.

    1995-01-01

    OBJECTIVE--To investigate the alterations in autonomic control of heart rate at high altitude and to test the hypothesis that hypoxaemic stress during exposure to high altitude induces non-linear, periodic heart rate oscillations, similar to those seen in heart failure and the sleep apnoea syndrome. SUBJECTS--11 healthy subjects aged 24-64. MAIN OUTCOME MEASURES--24 hour ambulatory electrocardiogram records obtained at baseline (1524 m) and at 4700 m. Simultaneous heart rate and respiratory dynamics during 2.5 hours of sleep by fast Fourier transform analysis of beat to beat heart rate and of an electrocardiographically derived respiration signal. RESULTS--All subjects had resting hypoxaemia at high altitude, with an average oxyhaemoglobin saturation of 81% (5%). There was no significant change in mean heart rate, but low frequency (0.01-0.05 Hz) spectral power was increased (P < 0.01) at high altitude. Time series analysis showed a complex range of non-linear sinus rhythm dynamics. Striking low frequency (0.04-0.06 Hz) heart rate oscillations were observed during sleep in eight subjects at high altitude. Analysis of the electrocardiographically derived respiration signal indicated that these heart rate oscillations correlated with low frequency respiratory oscillations. CONCLUSIONS--These data suggest (a) that increased low frequency power during high altitude exposure is not simply attributable to increased sympathetic modulation of heart rate, but relates to distinctive cardiopulmonary oscillations at approximately 0.05 Hz and (b) that the emergence of periodic heart rate oscillations at high altitude is consistent with an unstable cardiopulmonary control system that may develop on acute exposure to hypoxaemic stress.

  14. Attenuation of S-cone function at high altitude assessed by electroretinography.

    PubMed

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

    2014-04-01

    As impaired S-cone function has been reported psychophysically this study assessed S-cone function during high altitude exposure using electroretinography (ERG) and investigated a possible association with severity of acute mountain sickness (AMS). This work is related to the Tübingen High Altitude Ophthalmology (THAO) study. Standard ERG equipment was used (Diagnosys LLC, Cambridge, UK) with special protocol settings to extract S-cone function. Twelve subjects were analyzed in the current study and examinations were performed in Tübingen, Germany (341m) as baseline and thereafter at the Capanna Margherita, Italy (4559m) at high altitude. Results were compared using a paired t-test. Correlations between ERG measurements and oxygen saturation (SpO2), heart rate (HR) and scores of acute mountain sickness (AMS-C and LL) were calculated using Pearson's correlation coefficients. Amplitudes of S-cone b-waves decreased significantly at high altitude (p=0.02). No significant changes were observed for implicit times of b-waves (p=0.63), a-waves (p=0.75) or for a-wave amplitudes (p=0.78). The incidence of AMS was 50% at high altitude according to AMS-C and LL scores (AMS-C⩾0.7 and LL⩾5). Heart rate increased to 84±10min(-1) and SpO2 decreased to 71.9±5.7% at high altitude. No significant correlation was found between S-cone ERG parameters and SpO2, HR, AMS-C and LL. For the first time our study defines a significant impairment of S-cone function at high altitude time using objective state of the art examination methods. No correlation between the functional impairment of S-cones and levels of AMS was detected.

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

    PubMed

    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.

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  18. Catecholamine response during 12 days of high-altitude exposure (4, 300 m) in women.

    PubMed

    Mazzeo, R S; Child, A; Butterfield, G E; Mawson, J T; Zamudio, S; Moore, L G

    1998-04-01

    We have previously demonstrated that acclimatization to high altitude elicits increased sympathetic nerve activity in men. The purpose of this investigation was to determine 1) whether women respond in a similar manner as found previously in men and 2) the extent to which menstrual cycle phase influences this response. Sixteen eumenorrheic women (age, 23.6 +/- 1.2 yr; weight, 56.2 +/- 4. 3 kg) were studied at sea level and during 12 days of high-altitude exposure (4,300 m) in either their follicular (F; n = 11) or luteal (L; n = 5) phase. Twenty-four-hour urine samples were collected at sea level and during each day at altitude. Catecholamines were determined by high-performance liquid chromatography with electrochemical detection. Compared with sea-level values, urinary norepinephrine excretion increased significantly during altitude exposure, peaking on days 4-6. Thereafter, levels remained constant throughout the duration of altitude exposure. The magnitude of this increase was similar between the F (138%) and L (93%) phase. Urinary epinephrine levels were elevated on day 2 of altitude exposure compared with sea-level values for both F and L subjects (93%). Thereafter, urinary epinephrine excretion returned to sea-level values, and no differences were found between F and L subjects. Plasma catecholamine content was consistent with urinary values and supports the concept of an elevation in sympathetic activity over time at altitude. Mean and diastolic blood pressure as well as heart rate adjustments to high altitude correlated significantly with urinary norepinephrine excretion rates. It was concluded that 1) urinary and plasma catecholamine responses to 12 days of high-altitude exposure in women are similar to those previously documented to occur for men; 2) whereas no differences in catecholamine levels were observed between F- and L-phase assignments, for a given urinary norepinephrine excretion rate, blood pressure and heart rates were lower for F vs. L

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

    PubMed

    Weinbruch, Stephan; Nordby, Karl-Christian

    2013-12-01

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

  20. Characteristics of a rat model of an open craniocerebral injury at simulated high altitude

    PubMed Central

    Yu, An-Yong; Xu, Quan-Hong; Hu, Sheng-Li; Li, Fei; Chen, Yu-Jie; Yin, Yi; Zhu, Gang; Lin, Jiang-Kai

    2014-01-01

    To establish a rat model of an open craniocerebral injury at simulated high altitude and to examine the characteristics of this model. Rats were divided randomly into a normobaric group and a high-altitude group and their corresponding control groups. A rat model of an open craniocerebral injury was established with a nail gun shot. Simulated high-altitude conditions were established with a hypobaric chamber at 0.6 ATA to mimic pressure at an altitude of 4000 m. Mortality, brain water content (BWC), Evans blue content, pathology, regional cerebral blood flow (rCBF), partial pressure of brain tissue oxygen (PbtO2), and brainstem auditory-evoked potential were observed after injury. The mortality of the high-altitude group was significantly greater than that of the normobaric group within 72 h after injury (P<0.05). BWC and Evans blue content increased by 48 h after injury (P<0.05); pathological changes in damaged brains were more serious. In contrast, rCBF and PbtO2 had decreased markedly by 72 h (P<0.01); brainstem auditory-evoked potential values were significantly prolonged (P<0.05). Moreover, an inverse correlation between rCBF and BWC and a positive correlation between rCBF and PbtO2 were found. The rat model of an open craniocerebral injury at simulated high altitude can be established successfully using a nail gun shot and a hypobaric chamber. The injury characteristics at high altitude were more serious, rapid, and prolonged than those in the normobaric group. PMID:25191925

  1. A multi-omics strategy resolves the elusive nature of alkaloids in Podophyllum species.

    PubMed

    Marques, Joaquim V; Dalisay, Doralyn S; Yang, Hong; Lee, Choonseok; Davin, Laurence B; Lewis, Norman G

    2014-11-01

    Podophyllum hexandrum and, to a much lesser extent P. peltatum, are sources of podophyllotoxin, extensively used as a chemical scaffold for various anti-cancer drugs. In this study, integrated omics technologies (including advanced mass spectrometry/metabolomics, transcriptome sequencing/gene assemblies, and bioinformatics) gave unequivocal evidence that both plant species possess a hitherto unknown aporphine alkaloid metabolic pathway. Specifically, RNA-seq transcriptome sequencing and bioinformatics guided gene assemblies/analyses in silico suggested presence of transcripts homologous to genes encoding all known steps in aporphine alkaloid biosynthesis. A comprehensive metabolomics analysis, including UPLC-TOF-MS and MALDI-MS imaging in situ, then enabled detection, identification, localization and quantification of the aporphine alkaloids, magnoflorine, corytuberine and muricinine, in the underground and aerial tissues. Interestingly, the purported presence of alkaloids in Podophyllum species has been enigmatic since the 19th century, remaining unresolved until now. The evolutionary and phylogenetic ramifications of this discovery are discussed.

  2. High Altitude Infrasound Measurements using Balloon-Borne Arrays

    NASA Astrophysics Data System (ADS)

    Bowman, D. C.; Johnson, C. S.; Gupta, R. A.; Anderson, J.; Lees, J. M.; Drob, D. P.; Phillips, D.

    2015-12-01

    For the last fifty years, almost all infrasound sensors have been located on the Earth's surface. A few experiments consisting of microphones on poles and tethered aerostats comprise the remainder. Such surface and near-surface arrays likely do not capture the full diversity of acoustic signals in the atmosphere. Here, we describe results from a balloon mounted infrasound array that reached altitudes of up to 38 km (the middle stratosphere). The balloon drifted at the ambient wind speed, resulting in a near total reduction in wind noise. Signals consistent with tropospheric turbulence were detected. A spectral peak in the ocean microbarom range (0.12 - 0.35 Hz) was present on balloon-mounted sensors but not on static infrasound stations near the flight path. A strong 18 Hz signal, possibly related to building ventilation systems, was observed in the stratosphere. A wide variety of other narrow band acoustic signals of uncertain provenance were present throughout the flight, but were absent in simultaneous recordings from nearby ground stations. Similar phenomena were present in spectrograms from the last balloon infrasound campaign in the 1960s. Our results suggest that the infrasonic wave field in the stratosphere is very different from that which is readily detectable on surface stations. This has implications for modeling acoustic energy transfer between the lower and upper atmosphere as well as the detection of novel acoustic signals that never reach the ground. Our work provides valuable constraints on a proposed mission to detect earthquakes on Venus using balloon-borne infrasound sensors.

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

    PubMed Central

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

    2012-01-01

    Recent studies have identified genes involved in high-altitude adaptation in Tibetans. Genetic variants/haplotypes within regions containing three of these genes (EPAS1, EGLN1, and PPARA) are associated with relatively decreased hemoglobin levels observed in Tibetans at high altitude, providing corroborative evidence for genetic adaptation to this extreme environment. The mechanisms that afford adaptation to high-altitude hypoxia, however, remain unclear. Considering the strong metabolic demands imposed by hypoxia, we hypothesized that a shift in fuel preference to glucose oxidation and glycolysis at the expense of fatty acid oxidation would improve adaptation to decreased oxygen availability. Correlations between serum free fatty acids and lactate concentrations in Tibetan groups living at high altitude and putatively selected haplotypes provide insight into this hypothesis. An EPAS1 haplotype that exhibits a signal of positive selection is significantly associated with increased lactate concentration, the product of anaerobic glycolysis. Furthermore, the putatively advantageous PPARA haplotype is correlated with serum free fatty acid levels, suggesting a possible decrease in the activity of fatty acid oxidation. Although further studies are required to assess the molecular mechanisms underlying these patterns, these associations suggest that genetic adaptation to high altitude involves alteration in energy utilization pathways. PMID:22503288

  4. Structural and Functional Changes of the Human Macula during Acute Exposure to High Altitude

    PubMed Central

    Fischer, M. Dominik; Willmann, Gabriel; Schatz, Andreas; Schommer, Kai; Zhour, Ahmad; Zrenner, Eberhart; Bartz-Schmidt, Karl U.; Gekeler, Florian

    2012-01-01

    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 (TRTouter = 2.80±1.00 μm; mean change±95%CI). This change was inverted towards the inner four subfields (TRTinner = −1.89±0.97 μm) with significant reduction of TRT in the fovea (TRTfoveal = −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 (MSfoveal = −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, non

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

    PubMed Central

    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. PMID:25309583

  6. Establishment and evaluation of an experimental rat model for high-altitude intestinal barrier injury

    PubMed Central

    Luo, Han; Zhou, Dai-Jun; Chen, Zhang; Zhou, Qi-Quan; Wu, Kui; Tian, Kun; Li, Zhi-Wei; Xiao, Zhen-Liang

    2017-01-01

    In the present study an experimental high-altitude intestinal barrier injury rat model was established by simulating an acute hypoxia environment, to provide an experimental basis to assess the pathogenesis, prevention and treatment of altitude sickness. A total of 70 healthy male Sprague-Dawley rats were divided into two groups: Control group (group C) and a high-altitude hypoxia group (group H). Following 2 days adaptation, the rats in group H were exposed to a simulated 4,000-m, high-altitude hypoxia environment for 3 days to establish the experimental model. To evaluate the model, bacterial translocation, serum lipopolysaccharide level, pathomorphology, ultrastructure and protein expression in rats were assessed. The results indicate that, compared with group C, the rate of bacterial translocation and the apoptotic index of intestinal epithelial cells were significantly higher in group H (P<0.01). Using a light microscope it was determined that the intestinal mucosa was thinner in group H, there were fewer epithelial cells present and the morphology was irregular. Observations with an electron microscope indicated that the intestinal epithelial cells in group H were injured, the spaces among intestinal villi were wider, the tight junctions among cells were open and lanthanum nitrate granules (from the fixing solution) had diffused into the intestinal mesenchyme. The expression of the tight junction protein occludin was also decreased in group H. Therefore, the methods applied in the present study enabled the establishment of a stable, high-altitude intestinal barrier injury model in rats. PMID:28352318

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

    PubMed

    Lundby, Carsten; Sander, Mikael; van Hall, Gerrit; Saltin, Bengt; Calbet, José A L

    2006-06-01

    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. The capillary oxygen conductance of the lower extremity, a measure of oxygen diffusing capacity, was decreased in the Danish lowlanders after 8 weeks of acclimatization, but was still higher than the value obtained from the high altitude natives. The values were (in ml min(-1) mmHg(-1)) 55.2+/-3.7 (SL), 48.0+/-1.7 (W2), 37.8+/-0.4 (W8) and 27.7+/-1.5 (Nat). However, when correcting oxygen conductance for the observed reduction in maximal leg blood flow with acclimatization the effect diminished. When calculating a hypothetical leg V(o2max)at altitude using either the leg blood flow or the O(2) conductance values obtained at sea level, the former values were almost completely restored to sea level values. This would suggest that the major determinant V(o2max)for not to increase with acclimatization is the observed reduction in maximal leg blood flow and O(2) conductance.

  8. Preparation for high altitude expedition and changes in cardiopulmonary and biochemical laboratory parameters with ascent to high altitude in transplant patients and live donors.

    PubMed

    Suh, Kyung-Suk; Kim, Taehoon; Yi, Nam-Joon; Hong, Geun

    2015-11-01

    High-altitude climbing has many risks, and transplant recipients should discuss the associated risks and means of preparation with their physicians. This study aimed to help prepare athletic transplant donors and recipients for mountain climbing and was designed to evaluate physical performance and changes in cardiopulmonary and biochemical laboratory parameters of transplant recipients and donors in extreme conditions of high altitude. Ten subjects-six liver transplant recipients, two liver donors, and one kidney transplant recipient and his donor-were selected for this expedition to Island Peak, Himalayas, Nepal. Six healthy subjects joined the group for comparison. Blood samplings, vital signs, and oxygen saturation were evaluated, as was the Lake Louise acute mountain sickness score. All transplant subjects and donors reached the base camp (5150 m), and two liver transplant recipients and a liver donor reached the summit (6189 m). The blood levels of immunosuppressants were well maintained. The serum erythropoietin level was significantly higher in transplant recipients taking tacrolimus. With proper preparation, certain liver transplant patients and donors can tolerate strenuous physical activity and can tolerate high altitude similarly to normal healthy control subjects without significant biochemical laboratory changes in liver and renal function.

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

    NASA Technical Reports Server (NTRS)

    Miller, Sharon K.

    2005-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Foster, K.; Garcia, A.

    1972-01-01

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

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

    PubMed

    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.

  12. Incidence of high altitude pulmonary edema in low-landers during re-exposure to high altitude after a sojourn in the plains

    PubMed Central

    Apte, C.V.; Tomar, R.K.S.; Sharma, D.

    2015-01-01

    Background There is uncertainty whether acclimatized low-landers who return to high altitude after a sojourn at low altitude have a higher incidence of pulmonary edema than during the first exposure to high altitude. Methods This was a prospective cohort study consisting of men ascending to 3400 m by road (N = 1003) or by air (N = 4178). The study compared the incidence of high altitude pulmonary edema during first exposure vs the incidence during re-exposure in each of these cohorts. Results Pulmonary edema occurred in 13 of the 4178 entries by air (Incidence: 0.31%, 95% CI: 0.18%–0.53%). The incidence during first exposure was 0.18% (0.05%–0.66%) and 0.36% (0.2%–0.64%) during re-exposure (Fisher Exact Test for differences in the incidence (two-tailed) p = 0.534). The relative risk for the re-exposure cohort was 1.95 (95% CI, 0.43%–8.80%). Pulmonary edema occurred in 3 of the 1003 road entrants (Incidence: 0.30%, 95% CI: 0.08%–0.95%). All three cases occurred in the re-exposure cohort. Conclusion The large overlap of confidence intervals between incidence during first exposure and re-exposure; the nature of the confidence interval of the relative risk; and the result of the Fisher exact test, all suggest that this difference in incidence could have occurred purely by chance. We did not find evidence for a significantly higher incidence of HAPE during re-entry to HA after a sojourn in the plains. PMID:26288488

  13. [High altitude medicine is a concern also for Swedish primary care. Knowledge needed to identify high risk patients and provide appropriate advice].

    PubMed

    Kiwanuka, Olivia

    2015-05-26

    With the increasing amount of people traveling to high altitude regions, the number of people at risk of acquiring altitude illness increases. Altitude illness entails three syndromes; acute mountain sickness, high-altitude cerebral edema, and high-altitude pulmonary edema. These syndromes are potentially lethal acquired medical conditions that in most cases are preventable. Health care providers need to inform travelers of the risks associated with mountaineering and the prophylactic measures available as well as identify underlying conditions that require specific considerations. This article provides a summary of the pathophysiology, symptoms and treatment of altitude illness and aims to be an orientation for general practitioners.

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

    PubMed

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

    2000-01-01

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

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

    NASA Astrophysics Data System (ADS)

    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. Reduction of military high-altitude parachute entanglement using the controlled alternating parachute exit system.

    PubMed

    Hadley, A T; Hibst, J D

    1984-01-01

    The phenomenon of high-altitude parachute entanglement (HAE) results when two paratroopers have both a simultaneous and weak exit from the jump doors. They are then caught in the aircraft's slipstream and collision and entanglement follow. To avoid this phenomenon, the Controlled Alternating Parachute Exit System (CAPES) was introduced. CAPES focused upon manipulation of the exit technique to eliminate simultaneous paratrooper exit. Data from 90,894 consecutive parachute jumps revealed that the CAPES is highly successful in reducing te rate of high-altitude entanglement and the associated injury rate. CAPES seems to reduce the mid-altitude entanglement (MAE) and its injury rate but the results did not reach statistical significance as measured by chi square technique. The rate of landing or ground injuries, was essentially unchanged by the CAPES.

  17. A Hyperspectral Thermal Emission Spectrometer (HyTES) for High Altitude Applications

    NASA Astrophysics Data System (ADS)

    Mihaly, J. M.; Johnson, W. R.; Eng, B. T.; Staniszewski, Z. K.; Hook, S. J.

    2015-12-01

    The Hyperspectral Thermal Emission Spectrometer (HyTES) is an airborne imaging spectrometer developed by JPL and originally configured on the Twin Otter aircraft. The instrument utilizes a thermal infrared Dyson imaging spectrometer and provides 256 spectral channels between 7.5 and 12 micrometers with 512 spatial pixels cross-track over a 50 degree field of view. HyTES has successfully completed multiple campaigns on the low altitude Twin Otter platform and is now capable of routinely capturing multi-species gas plumes over urban and other science-applicable environments. Current system upgrades and modifications are underway to configure HyTES on the ER-2 high altitude aircraft. The ER-2 aircraft will fly at an altitude greater than 18 km (60,000 ft) and provide a wide swath width with 35 m ground pixel size. High altitude observations from HyTES on the ER-2 platform will be used to support HyspIRI TIR measurement development. The modifications to the system maintain the capability of the HyTES instrument on the Twin Otter aircraft and a new vacuum enclosure significantly reduces both the mass and volume of the instrument scanhead. The current instrument performance, upgrades, and specifications of the high altitude system will be presented.

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

    NASA Technical Reports Server (NTRS)

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

    PubMed

    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.

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

    PubMed

    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.

  1. High altitude bird migration at temperate latitudes: a synoptic perspective on wind assistance.

    PubMed

    Dokter, Adriaan M; Shamoun-Baranes, Judy; Kemp, Michael U; Tijm, Sander; Holleman, Iwan

    2013-01-01

    At temperate latitudes the synoptic patterns of bird migration are strongly structured by the presence of cyclones and anticyclones, both in the horizontal and altitudinal dimensions. In certain synoptic conditions, birds may efficiently cross regions with opposing surface wind by choosing a higher flight altitude with more favourable wind. We observed migratory passerines at mid-latitudes that selected high altitude wind optima on particular nights, leading to the formation of structured migration layers at varying altitude up to 3 km. Using long-term vertical profiling of bird migration by C-band Doppler radar in the Netherlands, we find that such migration layers occur nearly exclusively during spring migration in the presence of a high-pressure system. A conceptual analytic framework providing insight into the synoptic patterns of wind assistance for migrants that includes the altitudinal dimension has so far been lacking. We present a simple model for a baroclinic atmosphere that relates vertical profiles of wind assistance to the pressure and temperature patterns occurring at temperate latitudes. We show how the magnitude and direction of the large scale horizontal temperature gradient affects the relative gain in wind assistance that migrants obtain through ascending. Temperature gradients typical for northerly high-pressure systems in spring are shown to cause high altitude wind optima in the easterly sectors of anticyclones, thereby explaining the frequent observations of high altitude migration in these synoptic conditions. Given the recurring synoptic arrangements of pressure systems across temperate continents, the opportunities for exploiting high altitude wind will differ between flyways, for example between easterly and westerly oceanic coasts.

  2. An Examination of Corrections for High Altitude, High Speed Airborne Gravimetry

    NASA Astrophysics Data System (ADS)

    Preaux, S. A.; Diehl, T. M.; Childers, V. A.

    2009-12-01

    Standard corrections for airborne gravimetry are optimized for low altitude, low speed surveys. They are shown to have multi-mgal errors at the high altitude and high speed of the surveys for the GRAV-D project. Higher order methods for computing the Eötvös, free air and off-level corrections are investigated. The first and second order approximations for the Eötvös correction from Harlan (1968) have differences up to 6 mgal, depending on latitude, and include assumptions about Earth shape that are undesirable in a geodetic application. Similarly, first and second order approximations for the free air correction (Hackney and Featherstone 2003) differ by up to 20 mgal and contain assumptions about Earth shape. Including more sophisticated downward continuation when incorporating data into a geoid model may be preferable to applying a free air correction. Finally, an exact analytical method of correcting for aircraft motion and orientation is proposed which takes advantage of the GPS reference system to avoid Earth shape assumptions, eliminate approximations and yield vector gravity.

  3. High-altitude physiology and pathophysiology: implications and relevance for intensive care medicine

    PubMed Central

    Grocott, Michael; Montgomery, Hugh; Vercueil, Andre

    2007-01-01

    Cellular hypoxia is a fundamental mechanism of injury in the critically ill. The study of human responses to hypoxia occurring as a consequence of hypobaria defines the fields of high-altitude medicine and physiology. A new paradigm suggests that the physiological and pathophysiological responses to extreme environmental challenges (for example, hypobaric hypoxia, hyper-baria, microgravity, cold, heat) may be similar to responses seen in critical illness. The present review explores the idea that human responses to the hypoxia of high altitude may be used as a means of exploring elements of the pathophysiology of critical illness. PMID:17291330

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

    NASA Technical Reports Server (NTRS)

    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.

  5. DE-1 observations of counterstreaming electrons at high altitudes. [Dynamics Explorer-1

    NASA Technical Reports Server (NTRS)

    Lin, C. S.; Burch, J. L.; Winningham, J. D.; Menietti, J. D.; Hoffman, R. A.

    1982-01-01

    Observations of plasma at altitudes of 2-3 earth radii with the High Altitude Plasma Instrument (HAPI) on DE-1 indicate two distinct types of counterstreaming electron events. The type 1 event is characterized by two Maxwellian distribution functions, an isotropic high-temperature component and a field-aligned low temperature component. The type 2 event is distinguished by beams parallel and antiparallel to the magnetic field direction. The observations suggest two distinct mechanisms for accelerating counterstreaming electrons. Type 1 events appear to involve wave-particle interactions while type 2 events imply direct acceleration by oppositely-directed electric fields pointing toward the satellite along magnetic field lines.

  6. Effects of high-altitude electromagnetic pulse (HEMP) on telecommunications assets. Final Technical Information Bulletin

    SciTech Connect

    Not Available

    1988-06-01

    The objective of the Electromagnetic Pulse (EMP) Mitigation Program is the removal of EMP as a significant impediment to timely reestablishment of regional and national telecommunications following an attack against the United States that includes high-altitude nuclear detonations. The program approach involves estimating the effects of High-altitude EMP (HEMP) on telecommunication connectivity and traffic-handling capability, assessing the impact of available HEMP mitigation alternatives, and developing a comprehensive plan for implementating mitigation alternatives. This report summarizes available test results as they apply to the EMP Mitigation Program, and supercedes all previous versions of this report.

  7. Flexible Twist for Pitch Control in a High Altitude Long Endurance Aircraft with Nonlinear Response

    DTIC Science & Technology

    2008-12-01

    Information dominance is the key motivator for employing high-altitude long-endurance (HALE) aircraft to provide continuous coverage in the theaters of operation A joined-wing configuration of such a craft gives the advantage of a platform for higher resolution sensors. Design challenges emerge with structural flexibility that arise from a long-endurance aircraft design. The goal was to demonstrate that scaling the nonlinear response of a full-scale finite element model of a high-altitude long-endurance (HALE) aircraft was possible if the model was aeroelastically and

  8. [Physiological adaptations of sichuan golden monkeys (Rhinopithecus roxellana) to high altitude habitat in the Qinling Mountains].

    PubMed

    Gao, Yunfang

    2004-02-01

    The golden monkey (Rhinopithecus roxellana) is a special species in China, and possesses the highest altitude habitat (4,167 m) in all kinds of primates. So it is very important to study this monkey how to adapt to such a high and severe habitat. According to our research results in recent years and relative publications, this paper, from digestive, respiratory, blood, circulative and reproductive systems, inquired into the Sichuan golden monkey (Rhinopithecus roxellana), a named species for golden monkey, how to adapt to the high altitude habitat in the Qinling Mountains and what was the mechanism of these adaptations.

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

    PubMed Central

    2009-01-01

    High-altitude environments (>2,500 m) provide scientists with a natural laboratory to study the physiological and genetic effects of low ambient oxygen tension on human populations. One approach to understanding how life at high altitude has affected human metabolism is to survey genome-wide datasets for signatures of natural selection. In this work, we report on a study to identify selection-nominated candidate genes involved in adaptation to hypoxia in one highland group, Andeans from the South American Altiplano. We analysed dense microarray genotype data using four test statistics that detect departures from neutrality. Using a candidate gene, single nucleotide polymorphism-based approach, we identified genes exhibiting preliminary evidence of recent genetic adaptation in this population. These included genes that are part of the hypoxia-inducible transcription factor (HIF) pathway, a biochemical pathway involved in oxygen homeostasis, as well as three other genomic regions previously not known to be associated with high-altitude phenotypes. In addition to identifying selection-nominated candidate genes, we also tested whether the HIF pathway shows evidence of natural selection. Our results indicate that the genes of this biochemical pathway as a group show no evidence of having evolved in response to hypoxia in Andeans. Results from particular HIF-targeted genes, however, suggest that genes in this pathway could play a role in Andean adaptation to high altitude, even if the pathway as a whole does not show higher relative rates of evolution. These data suggest a genetic role in high-altitude adaptation and provide a basis for genotype/phenotype association studies that are necessary to confirm the role of putative natural selection candidate genes and gene regions in adaptation to altitude. PMID:20038496

  10. Comparing the contributions of ionospheric outflow and high-altitude production to O+ loss at Mars

    NASA Astrophysics Data System (ADS)

    Liemohn, Michael; Curry, Shannon; Fang, Xiaohua; Johnson, Blake; Fraenz, Markus; Ma, Yingjuan

    2013-04-01

    The Mars total O+ escape rate is highly dependent on both the ionospheric and high-altitude source terms. Because of their different source locations, they appear in velocity space distributions as distinct populations. The Mars Test Particle model is used (with background parameters from the BATS-R-US magnetohydrodynamic code) to simulate the transport of ions in the near-Mars space environment. Because it is a collisionless model, the MTP's inner boundary is placed at 300 km altitude for this study. The MHD values at this altitude are used to define an ionospheric outflow source of ions for the MTP. The resulting loss distributions (in both real and velocity space) from this ionospheric source term are compared against those from high-altitude ionization mechanisms, in particular photoionization, charge exchange, and electron impact ionization, each of which have their own (albeit overlapping) source regions. In subsequent simulations, the MHD values defining the ionospheric outflow are systematically varied to parametrically explore possible ionospheric outflow scenarios. For the nominal MHD ionospheric outflow settings, this source contributes only 10% to the total O+ loss rate, nearly all via the central tail region. There is very little dependence of this percentage on the initial temperature, but a change in the initial density or bulk velocity directly alters this loss through the central tail. However, a density or bulk velocity increase of a factor of 10 makes the ionospheric outflow loss comparable in magnitude to the loss from the combined high-altitude sources. The spatial and velocity space distributions of escaping O+ are examined and compared for the various source terms, identifying features specific to each ion source mechanism. These results are applied to a specific Mars Express orbit and used to interpret high-altitude observations from the ion mass analyzer onboard MEX.

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

    NASA Astrophysics Data System (ADS)

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

    1986-03-01

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

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

    PubMed

    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 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 elevated on descent

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

    PubMed Central

    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 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 elevated on

  14. Objective criteria for diagnosing high altitude pulmonary edema in acclimatized patients at altitudes between 2700 m and 3500 m

    PubMed Central

    Chawla, Anuj; Tripathi, K.K.

    2015-01-01

    Background The criteria used for diagnosing high altitude illnesses are largely based on Western literature. This study was undertaken to define objective, simple and reliable diagnostic criteria for high altitude pulmonary edema (HAPE) in Indian soldiers at altitudes between 2700 m and 3500 m. Methods Clinical data of 235 cases of HAPE that occurred between 2700 m and 3500 m were analysed. Receiver operator characteristic (ROC) curve analysis was used to select simple clinical parameters suitable for the diagnosis of HAPE at peripheral medical facilities. Cut-off values and their reliability for the diagnosis of HAPE were defined. Results HAPE occurred 2.8 ± 2.2 days after arrival at altitudes between 2700 m and 3500 m. Breathlessness, cough, chest discomfort and headache were the commonest symptoms. Low pulse oximetry (SPO2) values than normal for this altitude were seen in 89% of patients. ROC analysis of clinical parameters identified a heart rate more than 95 beats per minute (bpm), respiratory rate more than 21 per minute and SPO2 less than 86% while breathing ambient air at this altitude as diagnostic of HAPE. The sensitivity and specificity of these cut-offs was 0.66, 0.83 and 0.82 and 0.94, 0.95 and 0.93 respectively. Conclusion A heart rate of more than 95 bpm, respiratory rate more than 21 per minute and SPO2 less than 86% breathing room air in individuals complaining of breathlessness, cough, chest discomfort or headache within the first 5 days of arrival at altitudes between 2700 m and 3500 m is highly suggestive of HAPE. PMID:26663962

  15. The High Altitude Water Čerenkov (HAWC) TeV Gamma Ray Observatory

    NASA Astrophysics Data System (ADS)

    de la Fuente, Eduardo; Oceguera-Becerra, Tomas; García-Torales, Guillermo; García-Luna, José Luis

    The High Altitude Water Čerenkov observatory is a second generation ground based very high-energy γ-ray detector under construction in Sierra Negra, Puebla, México at an altitude of 4,100m. Higher altitude, improved design and a larger physical size used to reject cosmic ray background, make HAWC 10-20 times more sensitive than its predecessor Milagro. HAWC's large field of view (˜2sr) and over 90% duty cycle make it ideal to search for several types of TeV astronomical γ-ray sources, diffuse emission, cosmic anisotropy, and transients. Details and status of HAWC at date, and a galactic star formation application are here presented.

  16. Low-pressure electrical discharge experiment to simulate high-altitude lightning above thunderclouds

    NASA Technical Reports Server (NTRS)

    Jarzembski, M. A.; Srivastava, V.

    1995-01-01

    Recently, extremely interesting high-altitude cloud-ionosphere electrical discharges, like lightning above thunderstorms, have been observed from NASA's space shuttle missions and during airborne and ground-based experiments. To understand these discharges, a new experiment was conceived to simulate a thundercloud in a vacuum chamber using a dielectric in particulate form into which electrodes were inserted to create charge centers analogous to those in an electrified cloud. To represent the ionosphere, a conducting medium (metallic plate) was introduced at the top of the chamber. It was found that for different pressures between approximately 1 and 300 mb, corresponding to various upper atmospheric altitudes, different discharges occurred above the simulated thundercloud, and these bore a remarkable similarity to the observed atmospheric phenomena. At pressures greater than 300 mb, these discharges were rare and only discharges within the simulated thundercloud were observed. Use of a particulate dielectric was critical for the successful simulation of the high-altitude lightning.

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

    PubMed

    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.

  18. High-resolution Ceres High Altitude Mapping Orbit atlas derived from Dawn Framing Camera images

    NASA Astrophysics Data System (ADS)

    Roatsch, Th.; Kersten, E.; Matz, K.-D.; Preusker, F.; Scholten, F.; Jaumann, R.; Raymond, C. A.; Russell, C. T.

    2016-09-01

    The Dawn spacecraft Framing Camera (FC) acquired over 2400 clear filter images of Ceres with a resolution of about 140 m/pixel during the six cycles in the High Altitude Mapping Orbit (HAMO) phase between August 18 and October 21, 2015. We ortho-rectified the images from the first cycle and produced a global, high-resolution, controlled photomosaic of Ceres. This global mosaic is the basis for a high-resolution Ceres atlas that consists of 15 tiles mapped at a scale of 1:750,000. The nomenclature used in this atlas was proposed by the Dawn team and was approved by the International Astronomical Union (IAU). The full atlas is available to the public through the Dawn Geographical Information System (GIS) web page

  19. Pulmonary vascular reserve and exercise capacity at sea level and at high altitude.

    PubMed

    Pavelescu, Adriana; Faoro, Vitalie; Guenard, Hervé; de Bisschop, Claire; Martinot, Jean-Benoit; Mélot, Christian; Naeije, Robert

    2013-03-01

    It has been suggested that increased pulmonary vascular reserve, as defined by reduced pulmonary vascular resistance (PVR) and increased pulmonary transit of agitated contrast measured by echocardiography, might be associated with increased exercise capacity. Thus, at altitude, where PVR is increased because of hypoxic vasoconstriction, a reduced pulmonary vascular reserve could contribute to reduced exercise capacity. Furthermore, a lower PVR could be associated with higher capillary blood volume and an increased lung diffusing capacity. We reviewed echocardiographic estimates of PVR and measurements of lung diffusing capacity for nitric oxide (DL(NO)) and for carbon monoxide (DL(CO)) at rest, and incremental cardiopulmonary exercise tests in 64 healthy subjects at sea level and during 4 different medical expeditions at altitudes around 5000 m. Altitude exposure was associated with a decrease in maximum oxygen uptake (VO2max), from 42±10 to 32±8 mL/min/kg and increases in PVR, ventilatory equivalents for CO2 (V(E)/VCO2), DL(NO), and DL(CO). By univariate linear regression VO2max at sea level and at altitude was associated with V(E)/VCO2 (p<0.001), mean pulmonary artery pressure (mPpa, p<0.05), stroke volume index (SVI, p<0.05), DL(NO) (p<0.02), and DL(CO) (p=0.05). By multivariable analysis, VO2max at sea level and at altitude was associated with V(E)/VCO2, mPpa, SVI, and DL(NO). The multivariable analysis also showed that the altitude-related decrease in VO2max was associated with increased PVR and V(E)/VCO2. These results suggest that pulmonary vascular reserve, defined by a combination of decreased PVR and increased DL(NO), allows for superior aerobic exercise capacity at a lower ventilatory cost, at sea level and at high altitude.

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

    PubMed

    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.

  1. The first frontier: High altitude ballooning as a platform for student research experiences in science and engineering

    NASA Astrophysics Data System (ADS)

    Larson, Shane L.; Armstrong, John C.; Hiscock, William A.

    2009-06-01

    High altitude balloon platforms are ideal for providing hands-on research experiences for students in physics, atmospheric science, engineering, and other aerospace-related disciplines. We describe a basic high altitude balloon platform that can be constructed and operated by undergraduate students. The existing HARBOR and BOREALIS programs are used to illustrate some possible science and engineering research projects that students can pursue as part of a high-altitude flight program.

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

  3. Novel Airborne Imaging Polarimeter Undergoes High-Altitude Flight Testing

    NASA Technical Reports Server (NTRS)

    Diner, David J.; Pingree, Paula J.; Chipman, Russell A.

    2015-01-01

    Optical and signal processing technologies for high-accuracy polarimetric imaging, aimed at studying the impact of atmospheric haze and clouds on Earth's climate, have been demonstrated on checkout flights aboard NASA's ER-2 aircraft.

  4. De novo transcriptome analysis using 454 pyrosequencing of the Himalayan Mayapple, Podophyllum hexandrum

    PubMed Central

    2013-01-01

    Background The Himalayan or Indian Mayapple (Podophyllum hexandrum Royle) produces podophyllotoxin, which is used in the production of semisynthetic anticancer drugs. High throughput transcriptome sequences or genomic sequence data from the Indian Mayapple are essential for further understanding of the podophyllotoxin biosynthetic pathway. Results 454 pyrosequencing of a P. hexandrum cell culture normalized cDNA library generated 2,667,207 raw reads and 1,503,232 high quality reads, with an average read length of 138 bp. The denovo assembly was performed by Newbler using default and optimized parameters. The optimized parameter generated 40, 380 assembled sequences, comprising 12,940 contigs and 27,440 singlets which resulted in better assembly as compared to default parameters. BLASTX analysis resulted in the annotation of 40,380 contigs/singlet using a cut-off value of ≤1E-03. High similarity to Medicago truncatula using optimized parameters and to Populus trichocarpa using default parameters was noted. The Kyoto encyclopedia of genes and genomes (KEGG) analysis using KEGG Automatic Annotation Server (KAAS) combined with domain analysis of the assembled transcripts revealed putative members of secondary metabolism pathways that may be involved in podophyllotoxin biosynthesis. A proposed schematic pathway for phenylpropanoids and podophyllotoxin biosynthesis was generated. Expression profiling was carried out based on fragments per kilobase of exon per million fragments (FPKM). 1036 simple sequence repeats were predicted in the P. hexandrum sequences. Sixty-nine transcripts were mapped to 99 mature and precursor microRNAs from the plant microRNA database. Around 961 transcripts containing transcription factor domains were noted. High performance liquid chromatography analysis showed the peak accumulation of podophyllotoxin in 12-day cell suspension cultures. A comparative qRT-PCR analysis of phenylpropanoid pathway genes identified in the present data was

  5. Research on infrared radiation signatures of high-altitude plume based on DSMC method

    NASA Astrophysics Data System (ADS)

    Bao, Xingdong; Mao, Hongxia; Wu, Jie; Dong, Yanbing

    2016-10-01

    Exhaust plume flow field have the characteristics of high temperature, high speed and multi-species flow. Exhaust plume infrared signal are important basis of diagnosing, detecting and identifying plume spectrum. This paper focuses on the infrared radiation characteristics of high-altitude plume. The plume flows exhausted from a micro-nozzle of a low-thrust engine at high-altitude have been simulated numerically through using a DSMC method. Both the properties of plume flow at high altitude and the non-equilibrium effect related to rarefied gases are analyzed. Results are given numerically in good agreement with high-altitude plume observations. With the fields of pressure, temperature and main components of the exhaust plume as input data, the line-by line method was used to calculate the 2 5μm infrared spectral radiation properties of the plume. Different flight conditions are considered to analyze the influence on the infrared radiation characteristics. Some interesting conclusion are finally achieved.

  6. Viscous hypersonic shock-shock interaction on a blunt body at high altitude

    NASA Technical Reports Server (NTRS)

    Comeaux, Keith A.; Chapman, Dean R.; Maccormack, Robert W.

    1993-01-01

    The shock interaction produced when an incident oblique shock impinges on a blunt body, such as an engine inlet cowl lip of a hypersonic vehicle, is investigated for high altitude flight conditions. A perfect gas, Navier-Stokes numerical simulation of this problem at various altitudes representing continuum through transitional conditions is performed using the modified flux vector splitting method of Steger and Warming (1979). Two series of solutions are produced. First, a number-of-shock-positions are studied at a particular altitude and Mach number. Second, given a fixed shock position and Mach number, the interaction is investigated at several altitudes ranging from continuum to transitional flow conditions. It is shown that the interaction becomes fundamentally different as the density is lowered, and its effect on the overheating problem is progressively diminished. The maximum stagnation point heating at the highest altitude is reached only when the incident shock misses the cowl lip completely, and any interaction with the cowl bow shock that does occur takes place downstream and thus has little effect on the conditions at the stagnation point.

  7. A high-altitude barium radial injection experiment

    NASA Technical Reports Server (NTRS)

    Wescott, E. M.; Stenbaek-Nielsen, H. C.; Hallinan, T. J.; Deehr, C. S.; Romick, G. J.; Olson, J. V.; Roederer, J. G.; Sydora, R.

    1980-01-01

    A rocket launched from Poker Flat, Alaska, carried a new type of high-explosive barium shaped charge to 571 km, where detonation injected a thin disk of barium vapor with high velocity nearly perpendicular to the magnetic field. The TV images of the injection are spectacular, revealing three major regimes of expanding plasma which showed early instabilities in the neutral gas. The most unusual effect of the injection is a peculiar rayed barium-ion structure lying in the injection plane and centered on a 5 km 'black hole' surrounding the injection point. Preliminary electrostatic computer simulations show a similar rayed development.

  8. Review of "Do High Flyers Maintain Their Altitude?"

    ERIC Educational Resources Information Center

    Lee, Jaekyung

    2011-01-01

    The research report reviewed here concludes that many initially high-achieving students are falling further and further behind over the course of their years in school. The report intends to raise the alarm and to advocate for improved programs for these students. It is, however, a false alarm due to biased methodology and misleading arguments.…

  9. Experiments and Modeling of High Altitude Chemical Agent Release

    SciTech Connect

    Nakafuji, G.; Greenman, R.; Theofanous, T.

    2002-07-08

    Using ASCA data, we find, contrary to other researchers using ROSAT data, that the X-ray spectra of the VY Scl stars TT Ari and KR Aur are poorly fit by an absorbed blackbody model but are well fit by an absorbed thermal plasma model. The different conclusions about the nature of the X-ray spectrum of KR Aur may be due to differences in the accretion rate, since this Star was in a high optical state during the ROSAT observation, but in an intermediate optical state during the ASCA observation. TT Ari, on the other hand, was in a high optical state during both observations, so directly contradicts the hypothesis that the X-ray spectra of VY Sol stars in their high optical states are blackbodies. Instead, based on theoretical expectations and the ASCA, Chandra, and XMM spectra of other nonmagnetic cataclysmic variables, we believe that the X-ray spectra of VY Sol stars in their low and high optical states are due to hot thermal plasma in the boundary layer between the accretion disk and the surface of the white dwarf, and appeal to the acquisition of Chandra and XMM grating spectra to test this prediction.

  10. The High Altitude Pollution Program (1976-1982).

    DTIC Science & Technology

    1984-01-01

    burning, oxidation of amonia from fertilizer volatilization and, potentially, nuclear detonations. Of these, sources near the ground or in the lower...James E. and Thomas Sullivan, "An Extremely High Resolution Ozone Sensor for Spacelab," Proceedings of the Joint Symposium on Atmospheric 0, Vol. 1

  11. Meteorological Support of the Helios World Record High Altitude Flight to 96,863 Feet

    NASA Technical Reports Server (NTRS)

    Teets, Edward H., Jr.; Donohue, Casey J.; Wright, Patrick T.; DelFrate, John (Technical Monitor)

    2002-01-01

    In characterizing and understanding atmospheric behavior when conducting high altitude solar powered flight research flight planning engineers and meteorologists are able to maximize the use of available airspace and coordinate aircraft maneuvers with pilots to make the best use of changing sun elevation angles. The result of this cooperative research produced a new world record for absolute altitude of a non-rocket powered aircraft of 96,863 ft (29,531.4 m). The Helios prototype solar powered aircraft, with a wingspan of 247 ft (75.0m), reached this altitude on August 13, 2001, off the coast of Kauai, Hawaii. The analyses of the weather characterization, the planning efforts, and the weather-of-the-day summary that led to at record flight are described in this paper.

  12. VEGF189 expression is highly related to adaptation of the plateau pika (Ochotona curzoniae) inhabiting high altitudes.

    PubMed

    Li, Hongge; Guo, Songchang; Ren, Yongming; Wang, Depeng; Yu, Honghao; Li, Wenjing; Zhao, Xinquan; Chang, Zhijie

    2013-12-01

    The plateau pika (Ochotona curzonia) has adapted to high-altitude hypoxia during evolution. Higher microvessel density in specific tissues and a blunted hypoxic pulmonary vasoconstriction response are the critical components of this adaptation. VEGF, vascular endothelial growth factor, has proved to be a key regulator of angiogenesis in response to tissue hypoxia and to play an important role in vascular vasodilation. However, the role of VEGF in adaptation to high-altitude hypoxia in the plateau pika remains unknown. In this study, we cloned cDNAs for VEGF165 and VEGF189 and examined their expression in pikas inhabiting altitudes of 3200 and 4750 m. Phylogenetic analysis reveals that pika VEGF165 and VEGF189 are evolutionarily conserved. Real-time PCR analysis demonstrates that VEGF165 and VEGF189 display tissue and altitude-specific expression patterns. Interestingly, we found that the levels of VEGF189 mRNA are significantly higher than those of VEGF165 in the brain and muscle tissues of the pika, which is different from what was previously observed in sea-level mammals. VEGF189 mRNA levels in brain, muscle, and lung of the pika increased with increased habitat altitude, whereas VEGF165 shows less change. Our study suggests an important role for VEGF189 in adaptation to hypoxia by the plateau pika in the high-altitude environment.

  13. Low-altitude IR terrain and sea model development for a high-speed imaging fuze

    NASA Astrophysics Data System (ADS)

    Garbo, Dennis L.; Crow, Dennis R.; Coker, Charles F.; Cunard, Donald A.

    1999-07-01

    This paper is a continuation of a previous effort with an emphasis on the modeling techniques utilized to generate high-resolution IR terrain and sea backgrounds for low altitude scenarios. This paper briefly reiterates the IR scene generation process and unique modeling techniques implemented to build the various target models. This is followed by a detailed discussion on the development of the terrain and sea backgrounds necessary to support low altitude air engagement applications. Finally, a description of the process to render the composite target and background scenes using commercial graphics hardware to satisfy the frame-rate requirements for this program is presented.

  14. Balloon-Borne, High Altitude Gravimetry: The Flight of DUCKY II (October 1985)

    DTIC Science & Technology

    1987-10-28

    largely unpredictable environment, where little, if any gound truth"adta are available. The motions-of the balloon must be very accurately accounted for in...System Description 13 2.3.1.3 Method for Frequency Counting 16 2.3.2 Motion-Sensing Instrument Package 16 2.3.2.1 Instruments 17 2.3.2.2 System Description...Gravimetry The Flight of DUCKY II (October 1985) 1. INTRODUCTION Gravity field values at high altitudes, between altitudes for aerial surveys and

  15. Hypoxia: adapting to high altitude by mutating EPAS-1, the gene encoding HIF-2α.

    PubMed

    van Patot, Martha C Tissot; Gassmann, Max

    2011-01-01

    Living at high altitude is demanding and thus drives adaptational mechanisms. The Tibetan population has had a longer evolutionary period to adapt to high altitude than other mountain populations such as Andeans. As a result, some Tibetans living at high altitudes do not show markedly elevated red blood cell production as compared to South American high altitude natives such as Quechuas or Aymaras, thereby avoiding high blood viscosity creating cardiovascular risk. Unexpectedly, the responsible mutation(s) reducing red blood cell production do not involve either the gene encoding the blood hormone erythropoietin (Epo), or the corresponding regulatory sequences flanking the Epo gene. Similarly, functional mutations in the hypoxia-inducible transcription factor 1α (HIF-1α) gene that represents the oxygen-dependent subunit of the HIF-1 heterodimer, the latter being the main regulator of over 100 hypoxia-inducible genes, have not been described so far. It was not until very recently that three independent groups showed that the gene encoding HIF-2α, EPAS-1 (Wenger et al. 1997), represents a key gene mutated in Tibetan populations adapted to living at high altitudes (Beall et al. 2010 , Yi et al. 2010 , Simonson et al. 2010). Hypoxia-inducible transcription factors were first identified by the description of HIF-1 (Semenza et al. 1991 , 1992), which was subsequently found to enhance transcription of multiple genes that encode proteins necessary for rescuing from hypoxic exposure, including erythropoietic, angiogenic and glycolytic proteins. Then HIF-2 was identified (Ema et al. 1997 ; Flamme et al. 1997 ; Hogenesch et al. 1997 ; and Tian et al. 1997) and although it is highly similar to HIF-1 and has the potential to bind (Camenisch et al. 2001) and mediate (Mole et al. 2009) many of the same genes as HIF-1, its biological actions in response to hypoxia are distinct from those of HIF-1 (reviewed by Loboda et al. 2010). By now, several of these HIF-2 mediated

  16. High altitude measurements of fluctuations in the CMB

    SciTech Connect

    Davies, R.D. )

    1990-01-15

    The detection of fluctuations in the primordial CMB emission requires long integrations on limited areas of the sky; such extensive observations are best made from the ground on (high) dry sites. A current programme of measurements is described covering the frequency range 5 to 32 GHz using equipment at Teide Observatory, Tenerife, and in Antarctica. A bolometer system is under development for observations in the range 100 to 300 GHz to be made on Mauna Kea.

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

    During the Fukushima Daiichi nuclear power plant (FDNPP) accident, a dozen of high-altitude aerosol sampling stations, located between 850 and 3,454 m above sea level (a.s.l.), provided airborne activity levels across Europe (Fig. 1). This represents at most 5% of the total number of aerosol sampling locations that delivered airborne activity levels (at least one result) in Europe, in connection with this nuclear accident. High altitude stations are typically equipped with a high volume sampler that collects aerosols on filters. The Fukushima-labeled air mass arrival and the peak of airborne cesium-137 (137Cs) activity levels were registered in Europe at different dates depending on the location, with differences up to a factor of six on a regional scale. Besides this statement related to lowland areas, we have compared the maximum airborne levels registered at high-altitude European locations (850 m < altitudes < 3450 m) with what was observed at the closest lowland location. The vertical distribution of 137Cs peak level was not uniform even after a long travel time/distance from Japan. This being true at least in the atmospheric boundary layer and in the lower free troposphere. Moreover the relation '137Csmax vs. altitude' shows a decreasing trend (Fig. 2). Results and discussion : Comparison of 137Cs and 7Be levels shows simultaneous increases at least when the 137Cs airborne level rose for the first time (Fig. 3). Zugspitze and Jungfraujoch stations attest of a time shift between 7Be and 137Cs peak that can be due to the particular dynamic of air movements at such high altitudes. After the 137Cs peak value, the plume concentration decreased whatever the 7Be level. Due to the cosmogenic origin of 7Be, its increase in the ground-level air is usually associated with downwind air movements, i.e. stratospheric air intrusions or at least air from high-tropospheric levels, into lower atmospheric layers. This means that Fukushima-labeled air masses registered at ground

  18. An Investigation of the Applicability of High Altitude, Lighter-Than-Air (LTA) Vehicles to the Tactical Communications Relay Problem

    DTIC Science & Technology

    1974-08-20

    are employed at relatively low altitudes , usually below 20, 000 ft (6. 1 kin). Although France recently flew a stratospheric tethered balloon at 55...the start those which do not appear suitable for the high-6 altitude , multi-mode communications application. 2.1 Tethered Balloon Systems The first...free balloon systemsp i and their applicability to the high altitude communications relay problem. 6. Corbin, C. D. (1974) Portable Tethered Balloon

  19. Hyperintense White Matter Lesions in 50 High-Altitude Pilots with Neurologic Decompression Sickness

    DTIC Science & Technology

    2012-12-01

    presence of mild hypertension or mild hyperlipidemia. No pilot had a history of signifi cant head injury, signifi cant scuba diving history...episode of decompression illness associ- ated with diving , or high-altitude exposure other than that associated with USAF fl ight duties. HWM lesions

  20. 40 CFR Appendix III to Part 1068 - High-Altitude Counties

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

  1. REMOTE SENSING OF SEAGRASS WITH AVIRIS AND HIGH ALTITUDE AERIAL PHOTOGRAPHY

    EPA Science Inventory

    On May 15,2002 AVIRlS (Advanced VisuaJ/lnfrared Imaging Spectrometer) data and high altitude aerial photographs were acquired tor coastal .waters from Cape Lookout to Oregon Inlet, North Carolina. The study encompasses extensive areas of seagrass, federally protected submersed, r...

  2. Positive-Pressure Ventilator Systems at High Altitude: A Preliminary Study.

    DTIC Science & Technology

    1986-06-01

    Respiratory Distress Syndrome ( ARDS ), which is...of using mechanical ventilator systems with ARDA patients in high-altitude environments. DTIC A1 - a ADULT RESPIRATORY DISTRESS SYNDROME ARDS has been...capillary pressure) pulmonary edema and acute respiratory failure. The clinical physiology of severe ARDS is characterized by three phenomena: 1)

  3. Prevalence of Hypertension in a Tribal Land Locked Population at High Altitude

    PubMed Central

    Raina, Sunil Kumar; Chander, Vishav; Prasher, Chaman Lal; Raina, Sujeet

    2016-01-01

    Introduction. Extensive pubmed search reveals paucity of data on prevalence of hypertension in tribal population at high altitude. The data is all the more scarce from our part of India. Studies among tribal populations at high altitudes provide an interesting epidemiological window to study human evolution and adaptation to hypobaric hypoxia. Material and Methods. 401 participants above the age of 20 years were evaluated for blood pressure using a stratified simple random technique among villages located at high altitude. Results. Out of a total of 401 individuals studied 43 (males: 35; females: 8) were identified as hypertensive yielding a crude prevalence of 10.7%. The prevalence was higher in males (35/270; 12.9%) as compared to females (8/131; 6%). Prevalence was the highest in the age group of 30–39 among males (16/35; 45.7%) while it was the highest in the age group of 40–49 among females (7/8; 87%). Conclusions. Prevalence of 10.5% is noteworthy when interpreted in light of prevalence of hypertension in general population especially if hypobaric hypoxia is considered to have a protective effect on blood pressure in high altitude native populations. PMID:26989560

  4. On the HEMP environment for protective relays. [High-altitude electromagnetic pulse

    SciTech Connect

    Thomas, D.E.; Wiggins, C.M.; Salas, T.M. ); Barnes, P.R. )

    1994-01-01

    An assessment of the transient environment for protective relays produced by high-altitude electromagnetic pulse (HEMP) events is presented in this paper. Several mechanisms for coupling of HEMP to relay terminals are used to develop estimates of possible HEMP threats to relays. These predicted relay responses to HEMP events are compared to measured data on a solid state based relay's impulse strength.

  5. On the HEMP (high-altitude electromagnetic pulse) response of protective relays

    SciTech Connect

    Thomas, D.E.; Wiggins, C.M.; Barnes, P.R.; Oak Ridge National Lab., TN )

    1990-01-01

    An assessment of the susceptibility of protective relays to the transients produced by high-altitude electromagnetic pulse (HEMP) events is presented in this paper. Several mechanisms responsible for coupling of HEMP to relay terminals are examined. The predicted relay responses to HEMP events are compared to measured data on a solid state based relay's impulse. 11 refs., 16 figs.

  6. Morphology of the internal organs in the adaptation of animals to high-altitude conditions

    NASA Technical Reports Server (NTRS)

    Rakhimov, Y. A.; Belkin, V. S.; Usmanov, M. U.

    1975-01-01

    Disruption of metabolic processes in the walls of the blood vessels as well as changes in the functional activity of the endocrine glands play an important role in the process of an animal's accommodation to a combination of stress factors. Preliminary training of animals for stays at high-altitude markedly reduces the severity of the morphological picture.

  7. Oxygen enrichment and its application to life support systems for workers in high-altitude areas

    PubMed Central

    Li, Yongling; Liu, Yingshu

    2014-01-01

    Background: Workers coming from lowland regions are at risk of developing acute mountain sickness (AMS) when working in low oxygen high-altitude areas. Objectives: The aim of this study was to improve the conditions that lead to hypoxia and ensure the safety of the high-altitude workers. We analyzed the influence of low atmospheric pressure on the oxygen enrichment process in high-altitude areas using an engineering method called low-pressure swing adsorption (LPSA). Methods: Fourteen male subjects were screened and divided into three groups by type of oxygen supply system used: (1) oxygen cylinder group; (2) LPSA oxygen dispersal group; and (3) control group. These tests included arterial oxygen saturation (SaO2), pulse rate (PR), breaths per minute (BPM), and blood pressure (BP). Results: The results showed that after supplying oxygen using the LPSA method at the tunnel face, the SaO2 of workers increased; the incidence of acute mountain sickness, PR, and BPM significantly decreased. Conclusions: The LPSA life support system was found to be a simple, convenient, efficient, reliable, and applicable approach to ensure proper working conditions at construction sites in high-altitude areas. PMID:25000108

  8. Surveillance for early silicosis in high altitude miners using pulse oximetry.

    PubMed

    Donroe, Joseph A; Maurtua-Neumann, Paola J; Gilman, Robert H; Acosta, Ana Teresa; Cain, Gene; Parker, John E; Carhuaricra, Jaime Carlos Alvarez; Padilla, Juan Jose Retimozo; Mendoza, Daniel; Zimic, Mirko; Moore, David A J

    2008-01-01

    Two cross-sectional studies in a high altitude region of Perú evaluated the role of pulse oximetry for detection of silicosis in high-altitude miners. In study one, exercise pulse oximetry and chest radiographs were used to evaluate 343 silica-exposed miners and 141 unexposed subjects for evidence of silicosis. Study 2 investigated the association between exercise oxygen saturation and silicosis in 32 non-silicotic and 65 silicotic miners. In study one, age (Odds Ratio [OR] 1.10, 95% Cofidence Interval (CI) 1.07-1.12) and resting oxygen saturation (OR 0.95, 95%CI 0.90-0.99) were associated with silicosis. In study two, years of mining employment (OR 1.14, 95%CI 1.05-1.23) and exercise oxygen saturation at 30% maximum heart rate (OR 0.86, 95%CI 0.75-0.99) were associated with silicosis. Hypoxemia at rest and with exercise is associated with silicosis in high altitude miners. Pulse oximetry should be further investigated as a screening tool for silicosis at high altitudes.

  9. Non-high altitude methods for rapid screening of susceptibility to acute mountain sickness

    PubMed Central

    2013-01-01

    Background Acute mountain sickness (AMS) refers to the cerebral abnormalities typically triggered by exposure to hypobaric hypoxia at high altitude. Although AMS is not often life threatening, it can seriously impact health quality and decrease productivity. Thus, detection of potential susceptibility to AMS has become important for people arriving at high-altitude plateaus for the first time, including laborers and military staff. The aim of this review was to examine techniques which efficiently assess the susceptibility to AMS prior to exposure to high altitude. Methods By searching online databases, we retrieved studies with associations between AMS and methods to detect the susceptible people who were not exposed to high altitudes. Studies reporting significant correlation coefficients between screening methods and AMS scores were included. Results Several screening techniques of AMS susceptibility were found including cold pressor test, heart rate variability, and lung functions. Of these markers, heart rate variability was positively associated with AMS scores, while the rest were negatively associated with AMS scores. Conclusions We identified three physiological markers that were significantly associated with the risk of AMS. Although it is well known that simple sea level tests are not really helpful in predicting AMS currently, these markers, to some degree, may be employed as references in predicting susceptibility. PMID:24079477

  10. Development of unmanned aerial vehicle (UAV) based high altitude balloon (HAB) platform for active aerosol sampling

    NASA Astrophysics Data System (ADS)

    Lateran, S.; Sedan, M. F.; Harithuddin, A. S. M.; Azrad, S.

    2016-10-01

    The knowledge on the abundance and diversity of the minute particles or aerosols in the earth's stratosphere is still in its infancy as aerosol sampling at high-altitude still possess a lot of challenges. Thus far, high-altitude aerosol sampling has been conducted mostly using manned flights, which requires enormous financial and logistical resources. There had been researches for the utilisation of high altitude balloon (HAB) for active and passive aerosol samplings within the stratosphere. However, the gathered samples in the payload were either brought down by controlling the balloon air pressure or were just dropped with a parachute to slow the descend speed in order to reduce the impact upon landing. In most cases, the drop location of the sample are unfavorable such as in the middle of the sea, dense foliage, etc. Hence a system that can actively sample aerosols at high-altitude and improve the delivery method in terms of quality and reliability using unmanned aerial vehicle (UAV) is designed and tested in this study.

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

    DOEpatents

    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.

  12. Regular and chaotic motion of high altitude satellites

    NASA Astrophysics Data System (ADS)

    Wytrzyszczak, I.; Breiter, S.; Borczyk, W.

    We have computed the integrated autocorrelation function for different families of geosynchronous, inclined orbits in order to detect the regions of chaotic motion. In order to reduce the problems due to high eccentricity orbits, the logarithmic Hamiltonian regularization was applied and a symplectic integrator of the Wisdom Holman type was implemented. The orbits were integrated for an interval of 10,000 days. The results indicate that non-predictable orbits can be found in this relatively short time in the separatrix zone of the 1:1 tesseral resonance. Their chaotic nature results from the interchange between libration and circulation type of motion, and from the significant eccentricity growth, caused by the Kozai Lidov resonance. Some of these orbits intersects the Earth’s surface in time shorter than 20 years for a particular initial geometry of interacting bodies.

  13. Expressed sequence tags and molecular cloning and characterization of gene encoding pinoresinol/lariciresinol reductase from Podophyllum hexandrum.

    PubMed

    Wankhede, Dhammaprakash Pandhari; Biswas, Dipul Kumar; Rajkumar, Subramani; Sinha, Alok Krishna

    2013-12-01

    Podophyllotoxin, an aryltetralin lignan, is the source of important anticancer drugs etoposide, teniposide, and etopophos. Roots/rhizome of Podophyllum hexandrum form one of the most important sources of podophyllotoxin. In order to understand genes involved in podophyllotoxin biosynthesis, two suppression subtractive hybridization libraries were synthesized, one each from root/rhizome and leaves using high and low podophyllotoxin-producing plants of P. hexandrum. Sequencing of clones identified a total of 1,141 Expressed Sequence Tags (ESTs) resulting in 354 unique ESTs. Several unique ESTs showed sequence similarity to the genes involved in metabolism, stress/defense responses, and signalling pathways. A few ESTs also showed high sequence similarity with genes which were shown to be involved in podophyllotoxin biosynthesis in other plant species such as pinoresinol/lariciresinol reductase. A full length coding sequence of pinoresinol/lariciresinol reductase (PLR) has been cloned from P. hexandrum which was found to encode protein with 311 amino acids and show sequence similarity with PLR from Forsythia intermedia and Linum spp. Spatial and stress-inducible expression pattern of PhPLR and other known genes of podophyllotoxin biosynthesis, secoisolariciresinol dehydrogenase (PhSDH), and dirigent protein oxidase (PhDPO) have been studied. All the three genes showed wounding and methyl jasmonate-inducible expression pattern. The present work would form a basis for further studies to understand genomics of podophyllotoxin biosynthesis in P. hexandrum.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  15. Particle kinetic simulation of high altitude hypervelocity flight

    NASA Technical Reports Server (NTRS)

    Boyd, Iain; Haas, Brian L.

    1994-01-01

    Rarefied flows about hypersonic vehicles entering the upper atmosphere or through nozzles expanding into a near vacuum may only be simulated accurately with a direct simulation Monte Carlo (DSMC) method. Under this grant, researchers enhanced the models employed in the DSMC method and performed simulations in support of existing NASA projects or missions. DSMC models were developed and validated for simulating rotational, vibrational, and chemical relaxation in high-temperature flows, including effects of quantized anharmonic oscillators and temperature-dependent relaxation rates. State-of-the-art advancements were made in simulating coupled vibration - dissociation - recombination for post-shock flows. Models were also developed to compute vehicle surface temperatures directly in the code rather than requiring isothermal estimates. These codes were instrumental in simulating aerobraking of NASA's Magellan spacecraft during orbital maneuvers to assess heat transfer and aerodynamic properties of the delicate satellite. NASA also depended upon simulations of entry of the Galileo probe into the atmosphere of Jupiter to provide drag and flow field information essential for accurate interpretation of an onboard experiment. Finally, the codes have been used extensively to simulate expanding nozzle flows in low-power thrusters in support of propulsion activities at NASA-Lewis. Detailed comparisons between continuum calculations and DSMC results helped to quantify the limitations of continuum CFD codes in rarefied applications.

  16. Particle kinetic simulation of high altitude hypervelocity flight

    NASA Technical Reports Server (NTRS)

    Boyd, Iain; Haas, Brian L.

    1994-01-01

    Rarefied flows about hypersonic vehicles entering the upper atmosphere or through nozzles expanding into a near vacuum may only be simulated accurately with a direct simulation Monte Carlo (DSMC) method. Under this grant, researchers enhanced the models employed in the DSMC method and performed simulations in support of existing NASA projects or missions. DSMC models were developed and validated for simulating rotational, vibrational, and chemical relaxation in high-temperature flows, including effects of quantized anharmonic oscillators and temperature-dependent relaxation rates. State-of-the-art advancements were made in simulating coupled vibration-dissociation recombination for post-shock flows. Models were also developed to compute vehicle surface temperatures directly in the code rather than requiring isothermal estimates. These codes were instrumental in simulating aerobraking of NASA's Magellan spacecraft during orbital maneuvers to assess heat transfer and aerodynamic properties of the delicate satellite. NASA also depended upon simulations of entry of the Galileo probe into the atmosphere of Jupiter to provide drag and flow field information essential for accurate interpretation of an onboard experiment. Finally, the codes have been used extensively to simulate expanding nozzle flows in low-power thrusters in support of propulsion activities at NASA-Lewis. Detailed comparisons between continuum calculations and DSMC results helped to quantify the limitations of continuum CFD codes in rarefied applications.

  17. Sweat rate and prediction validation during high-altitude treks on Mount Kilimanjaro.

    PubMed

    Gonzalez, Richard R; Kenefick, Robert W; Muza, Stephen R; Hamilton, Scott W; Sawka, Michael N

    2013-02-15

    This study measured sweat rates (m(sw)) during high-altitude summer treks on Mt. Kilimanjaro to evaluate the efficacy of a recently developed fuzzy piecewise sweat prediction equation (Pw,sol) for application to high-altitude conditions. We hypothesized that the Pw,sol equation, adjusted for the barometric pressure (Pb) decreasing steadily at high altitude (Pw,sol+Alt), would allow for a more accurate prediction of m(sw) than Pw,sol unadjusted for altitude (Pw,sol(SL)). Fifteen men (43 ± 16 yr; 80 ± 22 kg) and seven women (46 ± 16 yr; 77 ± 18 kg) wearing hiking clothes (clo ∼1.15; clothing evaporative potential = 0.27) and carrying light loads (9 ± 2 kg), were studied during morning and afternoon treks (∼2-3 h) while ascending from 2,829 m to 3,505 m. After each trek, m(sw) was measured with specific biophysical parameters at 15-min intervals. During the trek day, Pb progressively declined (530 to 504 Torr), as solar radiation and ambient temperature (°C) rose transiently. During all treks, m(sw) ranged from 68 to 393 g·m(-2)·h(-1) (0.14 to 0.79 l/h). For each subject, derived Pw,sol(SL) and Pw,sol+Alt model outputs accurately predicted the morning and afternoon average m(sw) within a root mean square error of 0.145 l/h. No differences were found between Pw,sol(SL) and Pw,sol+Alt values. In conclusion, we report the first m(sw) measured during outdoor high-altitude activities and determined that Pw,sol(SL) equation can be used to predict fluid needs during high-altitude activities without alterations for lower Pb. This model prediction provides a valid water planning tool for outdoor activities at high altitude up to 3,500 m.

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

    PubMed Central

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

    2013-01-01

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

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

    PubMed

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

    2000-05-01

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

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

    NASA Astrophysics Data System (ADS)

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

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

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

    PubMed

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

    2016-04-01

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

  2. Comparison of high-altitude production and ionospheric outflow contributions to O+ loss at Mars

    NASA Astrophysics Data System (ADS)

    Liemohn, Michael W.; Curry, Shannon M.; Fang, Xiaohua; Ma, Yingjuan

    2013-07-01

    Mars Test Particle model is used (with background parameters from a magnetohydrodynamic code) to simulate the transport of O+ ions in the near-Mars space environment to study the source processes responsible for ion escape. The MHD values at this altitude are used to inject an ionospheric outflow source of ions for the Mars Test Particle (MTP). The resulting loss distributions (in both real and velocity space) from this ionospheric source term are compared against those from high-altitude ionization mechanisms, in particular photoionization, charge exchange, and electron impact ionization, each of which has its own source regions, albeit overlapping. For the nominal MHD settings, this ionospheric outflow source contributes only 10% to the total O+ loss rate at solar maximum, predominantly via the central tail region. This percentage has very little dependence on the initial temperature, but a change in the initial ion density or bulk velocity directly alters this loss through the central tail. A density or bulk velocity increase of a factor of 10 makes the ionospheric outflow loss comparable in magnitude to the loss from the combined high-altitude sources. The spatial and velocity space distributions of escaping O+ are examined and compared for the various source terms to identify features specific to each ion source mechanism. For solar minimum conditions, the nominal MHD ionospheric outflow settings yield a 27% contribution to the total O+ loss rate, i.e., roughly equal to any one of the three high-altitude source terms with respect to escape.

  3. Adaptability and stability of conilon coffee in areas of high altitude.

    PubMed

    Barbosa, D H G S; Rodrigues, W P; Vieira, H D; Partelli, F L; Viana, A P

    2014-09-26

    In view of the predicted models of global climate change and differences in prices and production costs, there is increased interest in Coffea canephora cultivation in areas of high altitude. However, this species is sensitive to low temperatures, where genotypes vary regarding adaptation/tolerance mechanisms, demonstrating genotype x environment interaction. The aim of this study was to evaluate the stability and adaptability of C. canephora varieties in high-altitude areas. The experiments were carried out in February 2004, in Bom Jesus do Itabapoana, Rio de Janeiro State, Brazil, at an altitude of 725 m. Four clonal varieties (EMCAPA 8111, EMCAPA 8121, EMCAPA 8131, and EMCAPA 8151) and five harvests (2006 to 2010) were used. The experimental design was randomized blocks with four treatments and six plots, with 12 plants in each plot and spaced 2.5 x 1.2 m. Adaptability and stability parameters were determined using methods based on nonparametric analysis and analysis of variance. The results showed that the EMCAPA 8131 had the best performance according to stability and adaptability parameters and may be promising for high-altitude regions.

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

    PubMed

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

    2013-01-07

    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.

  5. Widespread signals of convergent adaptation to high altitude in Asia and america.

    PubMed

    Foll, Matthieu; Gaggiotti, Oscar E; Daub, Josephine T; Vatsiou, Alexandra; Excoffier, Laurent

    2014-10-02

    Living at high altitude is one of the most difficult challenges that humans had to cope with during their evolution. Whereas several genomic studies have revealed some of the genetic bases of adaptations in Tibetan, Andean, and Ethiopian populations, relatively little evidence of convergent evolution to altitude in different continents has accumulated. This lack of evidence can be due to truly different evolutionary responses, but it can also be due to the low power of former studies that have mainly focused on populations from a single geographical region or performed separate analyses on multiple pairs of populations to avoid problems linked to shared histories between some populations. We introduce here a hierarchical Bayesian method to detect local adaptation that can deal with complex demographic histories. Our method can identify selection occurring at different scales, as well as convergent adaptation in different regions. We apply our approach to the analysis of a large SNP data set from low- and high-altitude human populations from America and Asia. The simultaneous analysis of these two geographic areas allows us to identify several candidate genome regions for altitudinal selection, and we show that convergent evolution among continents has been quite common. In addition to identifying several genes and biological processes involved in high-altitude adaptation, we identify two specific biological pathways that could have evolved in both continents to counter toxic effects induced by hypoxia.

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

    USGS Publications Warehouse

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

    2012-01-01

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

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

    PubMed

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

    2013-04-01

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

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

    PubMed

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

    2010-01-01

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

  9. Effect of high altitude and exercise on microvascular parameters in acclimatized subjects.

    PubMed

    Bauer, Andreas; Demetz, Florian; Bruegger, Dirk; Schmoelz, Martin; Schroepfer, Sebastian; Martignoni, André; Baschnegger, Heiko; Hoelzl, Josef; Thiel, Manfred; Choukér, Alexander; Peter, Klaus; Gamble, John; Christ, Frank

    2006-02-01

    The role of microvascular fluid shifts in the adaptation to hypobaric hypoxia and its contribution to the pathophysiology of AMS (acute mountain sickness) is unresolved. In a systematic prospective study, we investigated the effects of hypobaric hypoxia and physical exercise alone, and in combination, on microvascular fluid exchange and related factors. We used computer-assisted VCP (venous congestion plethysmography) on the calves of ten altitude-acclimatized volunteers. We investigated the effects of: (i) actively climbing to an altitude of 3196 m, (ii) airlifting these subjects to the same altitude, and (iii) exercise at low altitude. CFC (capillary filtration capacity), Pvi (isovolumetric venous pressure) and Qa (calf blood flow) were assessed before and after each procedure and then repeated after an overnight rest. Measurements of CFC showed no evidence of increased microvascular permeability after any of the procedures. Pvi was significantly decreased (P<0.001) from 20.3+/-4.4 to 8.9+/-4.3 mmHg after active ascent, and was still significantly lower (P=0.009) after overnight rest at high altitude (13.6+/-5.9 mmHg). No such changes were observed after the passive ascent (16.7+/-4.0 mmHg at baseline; 17.3+/-4.5 mmHg after passive ascent; and 19.9+/-5.3 mmHg after overnight rest) or after exercise at low altitude. After the active ascent, Qa was significantly increased. We also found a significant correlation between Qa, Pvi and the number of circulating white blood cells. In conclusion, we found evidence to support the hypothesis that increased microvascular permeability associated with AMS does not occur in acclimatized subjects. We also observed that the microvascular equilibrium pressure (Pvi) fell in inverse relation to the increase in Qa, especially in hypoxic exercise. We hypothesize that this inverse relationship reflects the haemodynamic changes at the microvascular interface, possibly attributable to the flow-induced increases in endothelial surface

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

    NASA Astrophysics Data System (ADS)

    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.

  11. Interplanetary dust particles, not wind blown dust, control high altitude ice clouds on Mars

    NASA Astrophysics Data System (ADS)

    Hartwick, Victoria; Toon, Owen B.

    2016-10-01

    Water ice clouds on Mars are commonly observed at high altitudes. However, current generation Mars three-dimensional general circulation models (GCM) struggle to reproduce clouds above approximately 20-30 km. On Mars, as on Earth, ice cloud formation likely initiates by heterogeneous nucleation, which requires a population of suspended ice nuclei contiguous with supersaturated atmospheric water vapor. Although supersaturation is observed at high altitudes and has been reproduced in models, models predict very few ice nuclei. The small number of ice nuclei in the upper atmosphere is due to the assumption in Mars GCMs that the only source of ice nuclei is dust from the Martian surface. However, terrestrial mesospheric noctilucent clouds have been shown to form by ice nucleation on particles originating from ablated micrometeroids. Therefore, it is reasonable to assume that a population of micrometeoric ablation biproducts on Mars exists and can act as a site for cloud nucleation at high altitudes. We present simulations using the Community Atmosphere Model for Mars (MarsCAM) based on the National Center for Atmospheric Research (NCAR) Community Atmosphere Model for Earth,coupled with a physically based, state-of-the-art cloud and dust physics model, the Community Aerosol and Radiation Model for Atmospheres (CARMA) to show that ablating micrometeoroids can yield abundant ice nuclei throughout the upper atmosphere of Mars. We find that simulations including a constant annual micrometeoroid flux allows us to reproduce the observed properties of high altitude water ice clouds including vertical distribution and particle size. In general, effective radius decreases with increasing altitude. We have additionally explored the impact of variable ablation rates. Preliminary results suggest that relatively high ablation rates, near or greater than 50%, are required to reproduce observed cloud features.

  12. Association between MT-CO3 haplotypes and high-altitude adaptation in Tibetan chicken.

    PubMed

    Sun, Jing; Zhong, Hang; Chen, Shi-Yi; Yao, Yong-Gang; Liu, Yi-Ping

    2013-10-15

    Genetic mutation in cytochrome c oxidase subunit III gene (MT-CO3) could influence the kinetics of cytochrome c oxidase (COX), which catalyzes oxygen transport capacity in oxidative phosphorylation. However, the potential relationship between MT-CO3 variants and high-altitude adaptation remains poorly understood in Tibetan chicken. Here, we sequenced MT-CO3 gene of 125 Tibetan chickens and 144 Chinese domestic chickens in areas at a low elevation (below 1,000 m). Eight single nucleotide polymorphisms (SNPs) were detected; and five of them (m.10081A>G, m.10115G>A, m.10270G>A, m.10336A>G and m.10447C>T) shared by Tibetan chicken and lowland chicken with the significant difference in their respective allele frequencies. Nine haplotypes (H1-H9) were finally defined. Among them, haplotype H4 was positively associated with high-altitude adaptation whereas haplotypes H6, H7 and H8 had negative association with high-altitude adaptation. The Median-joining profile suggested that haplotype H5 had the ancestral position to the other haplotypes but had no significant relationship with high-altitude adaptation. However, there was only m.10081A>G mutation differed from haplotype H4 and H5. Results also suggested that chickens with A allele at m.10081A>G, had over 2.6 times than those with G allele in the probability of the ability to adapt hypoxia. It suggests that the synonymous mutation m.10081A>G may be a prerequisite for shaping high-altitude adaptation-specific haplotypes.

  13. Chronic intermittent high altitude exposure, occupation, and body mass index in workers of mining industry.

    PubMed

    Esenamanova, Marina K; Kochkorova, Firuza A; Tsivinskaya, Tatyana A; Vinnikov, Denis; Aikimbaev, Kairgeldy

    2014-09-01

    The obesity and overweight rates in population exposed to chronic intermittent exposure to high altitudes are not well studied. The aim of the retrospective study was to evaluate whether there are differences in body mass index in different occupation groups working in intermittent shifts at mining industry at high altitude: 3800-4500 meters above sea level. Our study demonstrated that obesity and overweight are common in workers of high altitude mining industry exposed to chronic intermittent hypoxia. The obesity rate was lowest among miners as compared to blue- and white-collar employees (9.5% vs. 15.6% and 14.7%, p=0.013). Obesity and overweight were associated with older age, higher rates of increased blood pressure (8.79% and 5.72% vs. 1.92%), cholesterol (45.8% and 45.6% vs. 32.8%) and glucose (4.3% and 1.26% vs. 0.57%) levels as compared to normal body mass index category (p<0.0001 for all). There were differences in patterns of cholesterol and glucose levels in men and women employees according to occupation type. In conclusion, obesity and overweight rates are prevalent and associated with increase in blood pressure, cholesterol, and glucose levels in workers of mining industry exposed to intermittent high-altitude hypoxia. Therefore, assessment and monitoring of body mass index seems to be essential in those who live and work at high altitudes to supply the correct nutrition, modify risk factors, and prevent related disorders.

  14. Particle kinetic simulation of high altitude hypervelocity flight

    NASA Technical Reports Server (NTRS)

    Haas, Brian L.

    1993-01-01

    In this grant period, the focus has been on enhancement and application of the direct simulation Monte Carlo (DSMC) particle method for computing hypersonic flows of re-entry vehicles. Enhancement efforts dealt with modeling gas-gas interactions for thermal non-equilibrium relaxation processes and gas-surface interactions for prediction of vehicle surface temperatures. Both are important for application to problems of engineering interest. The code was employed in a parametric study to improve future applications, and in simulations of aeropass maneuvers in support of the Magellan mission. Detailed comparisons between continuum models for internal energy relaxation and DSMC models reveals that several discrepancies exist. These include definitions of relaxation parameters and the methodologies for implementing them in DSMC codes. These issues were clarified and all differences were rectified in a paper (Appendix A) submitted to Physics of Fluids A, featuring several key figures in the DSMC community as co-authors and B. Haas as first author. This material will be presented at the Fluid Dynamics meeting of the American Physical Society on November 21, 1993. The aerodynamics of space vehicles in highly rarefied flows are very sensitive to the vehicle surface temperatures. Rather than require prescribed temperature estimates for spacecraft as is typically done in DSMC methods, a new technique was developed which couples the dynamic surface heat transfer characteristics into the DSMC flow simulation code to compute surface temperatures directly. This model, when applied to thin planar bodies such as solar panels, was described in AIAA Paper No. 93-2765 (Appendix B) and was presented at the Thermophysics Conference in July 1993. The paper has been submitted to the Journal of Thermophysics and Heat Transfer. Application of the DSMC method to problems of practical interest requires a trade off between solution accuracy and computational expense and limitations. A

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

    PubMed

    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.

  16. Characteristics and Drivers of High-Altitude Ladybird Flight: Insights from Vertical-Looking Entomological Radar

    PubMed Central

    Jeffries, Daniel L.; Chapman, Jason; Roy, Helen E.; Humphries, Stuart; Harrington, Richard; Brown, Peter M. J.; Handley, Lori-J. Lawson

    2013-01-01

    Understanding the characteristics and drivers of dispersal is crucial for predicting population dynamics, particularly in range-shifting species. Studying long-distance dispersal in insects is challenging, but recent advances in entomological radar offer unique insights. We analysed 10 years of radar data collected at Rothamsted Research, U.K., to investigate characteristics (altitude, speed, seasonal and annual trends) and drivers (aphid abundance, air temperature, wind speed and rainfall) of high-altitude flight of the two most abundant U.K. ladybird species (native Coccinella septempunctata and invasive Harmonia axyridis). These species cannot be distinguished in the radar data since their reflectivity signals overlap, and they were therefore analysed together. However, their signals do not overlap with other, abundant insects so we are confident they constitute the overwhelming majority of the analysed data. The target species were detected up to ∼1100 m above ground level, where displacement speeds of up to ∼60 km/h were recorded, however most ladybirds were found between ∼150 and 500 m, and had a mean displacement of 30 km/h. Average flight time was estimated, using tethered flight experiments, to be 36.5 minutes, but flights of up to two hours were observed. Ladybirds are therefore potentially able to travel 18 km in a “typical” high-altitude flight, but up to 120 km if flying at higher altitudes, indicating a high capacity for long-distance dispersal. There were strong seasonal trends in ladybird abundance, with peaks corresponding to the highest temperatures of mid-summer, and warm air temperature was the key driver of ladybird flight. Climatic warming may therefore increase the potential for long-distance dispersal in these species. Low aphid abundance was a second significant factor, highlighting the important role of aphid population dynamics in ladybird dispersal. This research illustrates the utility of radar for studying high-altitude

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

    NASA Astrophysics Data System (ADS)

    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

  18. Ischemic preconditioning improves oxygen saturation and attenuates hypoxic pulmonary vasoconstriction at high altitude.

    PubMed

    Foster, Gary P; Giri, Paresh C; Rogers, Douglas M; Larson, Sophia R; Anholm, James D

    2014-06-01

    Exposure to hypoxic environments is associated with decreased arterial oxygen saturation and increased pulmonary artery pressures. Ischemic preconditioning of an extremity (IPC) is a procedure that stimulates vasoactive and inflammatory pathways that protect remote organ systems from ongoing or future ischemic injury. To test the effects of IPC on oxygen saturation and pulmonary artery pressures at high altitude, 12 healthy adult volunteers were evaluated in a randomized cross-over trial. IPC was administered utilizing a standardized protocol. IPC or placebo was administered daily for 5 days prior to ascent to altitude. All participants were evaluated twice at 4342 m altitude (placebo and IPC conditions separated by 4 weeks, randomized). The pulmonary artery systolic pressure (PASP) at 4342 m was significantly lower in the IPC condition than the placebo condition (36 ± 6.0 mmHg vs. 38.1 ± 7.6 mmHg, respectively, p = 0.035). Oxygen saturation at 4342 m was significantly higher with IPC compared to placebo (80.3 ± 8.7% vs. 75.3 ± 9.6%, respectively, p = 0.003). Prophylactic IPC treatment is associated with improved oxygen saturation and attenuation of the normal hypoxic increase in pulmonary artery pressures following ascent to high altitude.

  19. Human autonomic activity and its response to acute oxygen supplement after high altitude acclimatization.

    PubMed

    Bao, Xuping; Kennedy, Brian P; Hopkins, Susan R; Bogaard, Harm J; Wagner, Peter D; Ziegler, Michael G

    2002-11-29

    It is well established that after acclimatization at high altitude, many sympathetic pathways are hyperactive yet heart rate (HR) remains unchanged. In this study, we attempted to determine if this unchanged heart rate is due to compensatory mechanisms such as changes in parasympathetic activity or levels of receptors for autonomic neurotransmitters. We also examined the role played by hypoxia in these autonomic adaptations to high altitude. Three experiments were carried out on five healthy lowlanders both at sea level (SL) and after 2 weeks of acclimatization at 3800 m (Post-Ac) with: (a) placebo (control); (b) acute beta-adrenergic receptor blockade by propranolol (PRO), or (c) acute parasympathetic receptor blockade by glycopyrrolate (GLY). Compared with SL control values, post-Ac venous norepinephrine (NE) and dopamine increased by 96% (p < 0.001) and 55% (p < 0.05), but epinephrine and HR did not change. PRO resulted in a smaller decrease in HR (bpm) Post-Ac than at SL (15 +/- 6 vs. 21 +/- 6, p < 0.05), while GLY caused a greater increase in HR Post-Ac than at SL (59 +/- 8 vs. 45 +/- 6, p < 0.05). Breathing oxygen at SL concentration while at altitude did not decrease NE, or alter the effect of PRO on HR, but reduced the chronotropic effect of GLY by 14% (p < 0.05). These results suggest that after acclimatization to altitude, increased parasympathetic neurotransmitter release and decreased beta-adenoreceptor activity account for the unchanged HR despite enhanced sympathetic activity. Acute oxygen replacement rapidly counteracted the parasympathetic, but not sympathetic hyperactivity that occurs at high altitude.

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

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Astrophysics Data System (ADS)

    Tartari, G.

    2009-04-01

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

  2. Evolution of muscle phenotype for extreme high altitude flight in the bar-headed goose

    PubMed Central

    Scott, Graham R.; Egginton, Stuart; Richards, Jeffrey G.; Milsom, William K.

    2009-01-01

    Bar-headed geese migrate over the Himalayas at up to 9000 m elevation, but it is unclear how they sustain the high metabolic rates needed for flight in the severe hypoxia at these altitudes. To better understand the basis for this physiological feat, we compared the flight muscle phenotype of bar-headed geese with that of low altitude birds (barnacle geese, pink-footed geese, greylag geese and mallard ducks). Bar-headed goose muscle had a higher proportion of oxidative fibres. This increased muscle aerobic capacity, because the mitochondrial volume densities of each fibre type were similar between species. However, bar-headed geese had more capillaries per muscle fibre than expected from this increase in aerobic capacity, as well as higher capillary densities and more homogeneous capillary spacing. Their mitochondria were also redistributed towards the subsarcolemma (cell membrane) and adjacent to capillaries. These alterations should improve O2 diffusion capacity from the blood and reduce intracellular O2 diffusion distances, respectively. The unique differences in bar-headed geese were much greater than the minor variation between low altitude species and existed without prior exercise or hypoxia exposure, and the correlation of these traits to flight altitude was independent of phylogeny. In contrast, isolated mitochondria had similar respiratory capacities, O2 kinetics and phosphorylation efficiencies across species. Bar-headed geese have therefore evolved for exercise in hypoxia by enhancing the O2 supply to flight muscle. PMID:19640884

  3. Lockheed ER-2 #709 high altitude research aircraft during take off

    NASA Technical Reports Server (NTRS)

    1998-01-01

    ER-2 tail number 709, is one of two Airborne Science ER-2s used as science platforms by Dryden. The aircraft are platforms for a variety of high-altitude science missions flown over various parts of the world. They are also used for earth science and atmospheric sensor research and development, satellite calibration and data validation. The ER-2s are capable of carrying a maximum payload of 2,600 pounds of experiments in a nose bay, the main equipment bay behind the cockpit, two wing-mounted superpods and small underbody and trailing edges. Most ER-2 missions last about six hours with ranges of about 2,200 nautical miles. The aircraft typically fly at altitudes above 65,000 feet. On November 19, 1998, the ER-2 set a world record for medium weight aircraft reaching an altitude of 68,700 feet. The aircraft is 63 feet long, with a wingspan of 104 feet. The top of the vertical tail is 16 feet above ground when the aircraft is on the bicycle-type landing gear. Cruising speeds are 410 knots, or 467 miles per hour, at altitude. A single General Electric F-118 turbofan engine rated at 17,000 pounds thrust powers the ER-2.

  4. Comparison of the acceptability ratings of appetizers under laboratory, base level and high altitude field conditions.

    PubMed

    Premavalli, K S; Wadikar, D D; Nanjappa, C

    2009-08-01

    The relationship between laboratory and field ratings was investigated for six different appetizers, including four ready-to-reconstitute mixes and two ready-to-eat munches. Liking ratings on a 5-point hedonic scale were obtained from an Indian Army field study at base level as well as at an altitude of 11,500 ft above sea level and for the same appetizers in the laboratory. The field trials of the six products were conducted in two phases and results revealed that the products were more acceptable at altitude, with increased liking scores as compared to base level. Subjective ratings for hunger revealed that at altitude, appetizer consumption had stimulated the appetite of the soldiers. The ability of laboratory ratings to predict acceptability of foods consumed under realistic conditions appears to depend on the convenience of the appetizer as well as the environmental conditions and the psycho-physiological status of the participants. The appetizers received higher ratings at altitude because of the pungent and spicy nature of appetizer mixes as compared with base field and laboratory conditions. However, for all the appetizers the pungent and sweet taste of the appetizer munches was highly preferred.

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

    NASA Technical Reports Server (NTRS)

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

    1996-01-01

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

  6. Influence of Cerebral Blood Flow on Central Sleep Apnea at High Altitude

    PubMed Central

    Burgess, Keith R.; Lucas, Samuel J.E.; Shepherd, Kelly; Dawson, Andrew; Swart, Marianne; Thomas, Kate N.; Lucas, Rebekah A.I.; Donnelly, Joseph; Peebles, Karen C.; Basnyat, Rishi; Ainslie, Philip N.

    2014-01-01

    Study Objectives: To further our understanding of central sleep apnea (CSA) at high altitude during acclimatization, we tested the hypothesis that pharmacologically altering cerebral blood flow (CBF) would alter the severity of CSA at high altitude. Design: The study was a randomized, placebo-controlled single-blind study. Setting: A field study at 5,050 m in Nepal. Patients or Participants: We studied 12 normal volunteers. Interventions: Between days 5 to10 at high altitude, CBF velocity (CBFv) was increased by intravenous (IV) acetazolamide (10 mg/kg) and reduced by oral indomethacin (100 mg). Measurements and Results: Arterial blood gases, hypoxic and hypercapnic ventilatory responses, and CBFv and its reactivity to carbon dioxide were measured awake. Overnight polysomnography was performed. The central apnea-hypopnea index was elevated following administration of indomethacin (89.2 ± 43.7 to 112.5 ± 32.9 events/h; mean ± standard deviation; P < 0.05) and was reduced following IV acetazolamide (89.2 ± 43.7 to 47.1 ± 48.1 events/h; P < 0.001). Intravenous acetazolamide elevated CBFv at high altitude by 28% (95% confidence interval [CI]: 22-34%) but did not affect ventilatory responses. The elevation in CBFv was partly mediated via a selective rise in partial pressure of arterial carbon dioxide (PaCO2) (28 ± 4 to 31 ± 3 mm Hg) and an associated fall in pH (P < 0.01). Oral indomethacin reduced CBFv by 23% (95% CI: 16-30%), blunted CBFv reactivity, and increased the hypercapnic ventilatory response by 66% (95% CI: 30-102%) but had no effect on PaCO2 or pH. Conclusion: Our findings indicate an important role for cerebral blood flow regulation in the pathophysiology of central sleep apnea at high altitude. Citation: Burgess KR, Lucas SJE, Shepherd K, Dawson A, Swart M, Thomas KN, Lucas RAI, Donnelly J, Peebles KC, Basnyat R, Ainslie PN. Influence of cerebral blood flow on central sleep apnea at high altitude. SLEEP 2014;37(10):1679-1687. PMID:25197804

  7. Design and Predictions for a High-Altitude (Low-Reynolds-Number) Aerodynamic Flight Experiment

    NASA Technical Reports Server (NTRS)

    Greer, Donald; Hamory, Phil; Krake, Keith; Drela, Mark

    1999-01-01

    A sailplane being developed at NASA Dryden Flight Research Center will support a high-altitude flight experiment. The experiment will measure the performance parameters of an airfoil at high altitudes (70,000 to 100,000 ft), low Reynolds numbers (200,000 to 700,000), and high subsonic Mach numbers (0.5 and 0.65). The airfoil section lift and drag are determined from pitot and static pressure measurements. The locations of the separation bubble, Tollmien-Schlichting boundary layer instability frequencies, and vortex shedding are measured from a hot-film strip. The details of the planned flight experiment are presented. Several predictions of the airfoil performance are also presented. Mark Drela from the Massachusetts Institute of Technology designed the APEX-16 airfoil, using the MSES code. Two-dimensional Navier-Stokes analyses were performed by Mahidhar Tatineni and Xiaolin Zhong from the University of California, Los Angeles, and by the authors at NASA Dryden.

  8. Design and Predictions for High-Altitude (Low Reynolds Number) Aerodynamic Flight Experiment

    NASA Technical Reports Server (NTRS)

    Greer, Donald; Harmory, Phil; Krake, Keith; Drela, Mark

    2000-01-01

    A sailplane being developed at NASA Dryden Flight Research Center will support a high-altitude flight experiment. The experiment will measure the performance parameters or an airfoil at high altitudes (70,000 - 100,000 ft), low Reynolds numbers (2 x 10(exp 5) - 7 x 10(exp 5)), and high subsonic Mach numbers (0.5 and 0.65). The airfoil section lift and drag are determined from pilot and static pressure measurements. The locations of the separation bubble, Tollmien-Schlichting boundary-layer instability frequencies, and vortex shedding are measured from a hot-film strip. The details of the planned flight experiment are presented as well as several predictions of the airfoil performance.

  9. Effects of growth, diving history, and high altitude on blood oxygen capacity in harbor seals

    NASA Technical Reports Server (NTRS)

    Kodama, A. M.; Elsner, R.; Pace, N.

    1977-01-01

    Blood volume and body composition for diving and nondiving harbor seals were measured at six-week intervals during a 10-month period of captitivity. Whole body hematocrit, red cell volume per kg of lean body mass, and total circulating hemoglobin per kg lean body mass were significantly higher in the diving group, but relatively large blood volumes expressed in terms of body weight (11-12%) were found in both groups. A pair of harbor seals exposed to high altitude for about three months registered significant increases in red cell volume, blood hemoglobin levels, and blood volume expressed in terms of body weight; results of alveolar gas analyses indicate that hyperventilation also occurred. These typical mammalian responses to hypoxia suggest that the harbor seal's large blood volume and high hemoglobin content are an expression of phylogenetic control, and that in spite of its adaptability to apnea during its diving life, the animal cannot be considered preacclimatized to high altitude.

  10. Modeling of High-altitude Atmospheric Dispersion Using Climate and Meteorological Forecast Data

    SciTech Connect

    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

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

    PubMed Central

    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

    2016-01-01

    Objectives 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. Design Cross-sectional epidemiological study on Tibetan highlanders. Participants 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). Main outcome measure 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. Results 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 <3500 m, respectively). After adjusting for lifestyle change, hypoxaemia and polycythaemia were closely associated with glucose intolerance. Conclusions 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

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

    PubMed Central

    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.

    2015-01-01

    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 βA-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 βA-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. PMID:26460028

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

    PubMed

    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.

  14. High-altitude meteors and meteoroid fragmentation observed at the Jicamarca Radio Observatory

    NASA Astrophysics Data System (ADS)

    Gao, B.; Mathews, J. D.

    2015-02-01

    Modern high-power, large-aperture (HPLA) radars have been used in a variety of investigations including the investigation of meteoroid fragmentation. The identification of fragmentation has been based on a detailed interpretation, based on radio science, of head- and trail-echo properties. We now extend the discussion of fragmenting meteoroids to include apparent high-altitude (130-180 km) meteors observed at the Jicamarca Radio Observatory (JRO). While there have been a few reports of high-altitude meteors observed both optically and with radar, the meteor radar community has remained sceptical, with suspicions of antenna side-lobe contamination being the most commonly raised objection. We report results from two sets of meteor observations carried out at JRO in 2010 April. Our findings include meteoroid fragmentation results that are similar to those from the Arecibo VHF radar. These findings lead to the conclusions that fragmentation is not only observed at the JRO but that k⊥B scattering adds an interesting additional radio science dimension to the issue. We also report on apparent high-altitude meteor events that, if ultimately confirmed, offer insight into sputtering as a source of the meteor ionization, and perhaps indicate the unique importance of magnetic field geometry in these head-echo observations. Also, new, apparently high-altitude transient events, likely related to the meteoroid flux, have been identified. In presenting these results, we note our careful calibration of the JRO radar, utilizing satellite returns in order to largely, if not totally, exclude side-lobe contamination and other possible error sources, as reported in our companion paper.

  15. Fasciola hepatica and lymnaeid snails occurring at very high altitude in South America.

    PubMed

    Mas-Coma, S; Funatsu, I R; Bargues, M D

    2001-01-01

    Fascioliasis due to the digenean species Fasciola hepatica has recently proved to be an important public health problem, with human cases reported in countries of the five continents, including severe symptoms and pathology, with singular epidemiological characteristics, and presenting human endemic areas ranging from hypo- to hyperendemic. One of the singular epidemiological characteristics of human fascioliasis is the link of the hyperendemic areas to very high altitude regions, at least in South America. The Northern Bolivian Altiplano, located at very high altitude (3800-4100 m), presents the highest prevalences and intensities of human fascioliasis known. Sequences of the internal transcribed spacers ITS-1 and ITS-2 of the nuclear ribosomal DNA of Altiplanic Fasciola hepatica and the intermediate snail host Lymnaea truncatula suggest that both were recently introduced from Europe. Studies were undertaken to understand how the liver fluke and its lymnaeid snail host adapted to the extreme environmental conditions of the high altitude and succeeded in giving rise to high infection rates. In experimental infections of Altiplanic lymnaeids carried out with liver fluke isolates from Altiplanic sheep and cattle, the following aspects were studied: miracidium development inside the egg, infectivity of miracidia, prepatent period, shedding period, chronobiology of cercarial emergence, number of cercariae shed by individual snails, survival of molluscs at the beginning of the shedding process, survival of infected snails after the end of the shedding period and longevity of shedding and non-shedding snails. When comparing the development characteristics of European F. hepatica and L. truncatula, a longer cercarial shedding period and a higher cercarial production were observed, both aspects related to a greater survival capacity of the infected lymnaeid snails from the Altiplano. These differences would appear to favour transmission and may be interpreted as strategies

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

    NASA Astrophysics Data System (ADS)

    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.

  17. Current Status of a NASA High-Altitude Balloon-Based Observatory for Planetary Science

    NASA Technical Reports Server (NTRS)

    Varga, Denise M.; Dischner, Zach

    2015-01-01

    Recent studies have shown that progress can be made on over 20% of the key questions called out in the current Planetary Science Decadal Survey by a high-altitude balloon-borne observatory. Therefore, NASA has been assessing concepts for a gondola-based observatory that would achieve the greatest possible science return in a low-risk and cost-effective manner. This paper addresses results from the 2014 Balloon Observation Platform for Planetary Science (BOPPS) mission, namely successes in the design and performance of the Fine Pointing System. The paper also addresses technical challenges facing the new Gondola for High Altitude Planetary Science (GHAPS) reusable platform, including thermal control for the Optical Telescope Assembly, power generation and management, and weight-saving considerations that the team will be assessing in 2015 and beyond.

  18. High altitude color photography as a tool for regional analysis: As demonstrated for southeastern Florida

    NASA Technical Reports Server (NTRS)

    Eyre, L. A.

    1972-01-01

    High altitude color and color infrared photography of the tri-county region of southeast Florida made it feasible to evaluate its potential for quantifying the dimensions of regional change. Attention was focused upon three main aspects of change in the region, which in fact overlap. These were; (1) the transformation of the southeast Florida wetlands; (2) the expansion of agriculture; and (3) the growth of the urbanized area. The development analyzed covered the period of thirteen years from 1956 to 1969. Results using this new 18 km photography were superior because of the degree of resolution, the combined power of color and color infrared interpretation, and the large area covered by each frame. The greatest advantage of high altitude imagery is the time-saving element, since it is possible to delineate and identify major geographic patterns over thousands of sq km very rapidly.

  19. Use of Cameras in High Altitude Ballooning as a Data Integration Tool

    NASA Astrophysics Data System (ADS)

    Gatrell, Sharon; Parkinson, Murielle; Armstrong, John

    2010-10-01

    Integrating data from multiple sensor systems can be a challenge, especially in high altitude ballooning, where violent motion, high humidity and low temperatures can cause system failures. Camera intervalometers can be used to correlate and corroborate data from multiple systems, and relate data on board to real time. Cameras are good candidates because they are more compact than other sensor arrays, can be insulated without interfering with their operation, and can be used to independently verify multiple sensor reading simultaneously (atmosphere quality, altitude, acceleration, orientation, etc.) while providing a record of elapsed time. Inexpensive, off-the-shelf cameras can be easily modified to work unattended in hostile environments. We will present information on changing the camera's metafile (data header) to include 3-D location and other details not normally included. We will also show image correlation with other sensors such as aerosols, real time clocks and motion.

  20. The physiology of extremes: Ancel Keys and the International High Altitude Expedition of 1935.

    PubMed

    Tracy, Sarah W

    2012-01-01

    This article examines the International High Altitude Expedition of 1935 and its significance in the life and science of Ancel Keys. Both the expedition and Keys's story afford excellent opportunities to explore the growing reach of interwar physiology into extreme climates-whether built or natural. As IHAE scientists assessed human performance and adaptation to hypoxia, low barometric pressure, and cold, they not only illuminated the physiological and psychological processes of high altitude acclimatization, but they also drew borderlines between the normal and the pathological, paved the way for the neocolonial exploitation of natural and human resources in Latin America, and pioneered field methods in physiology that were adapted and adopted by the Allied Forces during the Second World War. This case study in the physiology of place reveals the power and persistence of environmental determinism within biomedicine well into the twentieth century.

  1. Effects of high-altitude electromagnetic pulse (HEMP) on telecommunications assets. Volume 1. Final report

    SciTech Connect

    Not Available

    1987-05-15

    In response to Executive Order (E.O.) 12472 and National Security Decision Directive 97 (NSDD-97), the Office of the Manager, National Communications System (OMNCS) has begun an ElectroMagnetic Pulse (EMP) mitigation program. The objective of this program is the removal of EMP as a significant impediment to timely reestablishment of regional and national telecommunications following an attack against the United States that includes high-altitude nuclear detonations. The methodology for developing an EMP mitigation program plan was described in the National Communications System (NCS) report Electromagnetic Pulse Mitigation Program Approach of July 1982. The program approach involves estimating the effects of High-altitude EMP (HEMP) on telecommunications capabilities, assessing the impact of available HEMP mitigation alternatives, and developing a comprehensive plan for implementing mitigation alternatives. The purpose of this report is to summarize available test results as they apply to the EMP mitigation program.

  2. Human high-altitude adaptation: forward genetics meets the HIF pathway

    PubMed Central

    Bigham, Abigail W.

    2014-01-01

    Humans have adapted to the chronic hypoxia of high altitude in several locations, and recent genome-wide studies have indicated a genetic basis. In some populations, genetic signatures have been identified in the hypoxia-inducible factor (HIF) pathway, which orchestrates the transcriptional response to hypoxia. In Tibetans, they have been found in the HIF2A (EPAS1) gene, which encodes for HIF-2α, and the prolyl hydroxylase domain protein 2 (PHD2, also known as EGLN1) gene, which encodes for one of its key regulators, PHD2. High-altitude adaptation may be due to multiple genes that act in concert with one another. Unraveling their mechanism of action can offer new therapeutic approaches toward treating common human diseases characterized by chronic hypoxia. PMID:25319824

  3. High altitude simulation, substance P and airway rapidly adapting receptor activity in rabbits.

    PubMed

    Bhagat, R; Yasir, A; Vashisht, A; Kulshreshtha, R; Singh, S B; Ravi, K

    2011-09-15

    To investigate whether there is a change in airway rapidly adapting receptor (RAR) activity during high altitude exposure, rabbits were placed in a high altitude simulation chamber (barometric pressure, 429 mm Hg). With 12 h exposure, when there was pulmonary congestion, an increase in basal RAR activity was observed. With 36 h exposure, when there was alveolar edema, there was a further increase in basal RAR activity. In these backgrounds, there was an increase in the sensitivity of the RARs to substance P (SP). To assess whether there was an increase in lung SP level, neutral endopeptidase activity was determined which showed a decrease in low barometric pressure exposed groups. It is concluded that along with the SP released, pulmonary congestion and edema produced, respectively by different durations of low barometric pressure exposure cause a progressive increase in RAR activity which may account for the respiratory symptoms reported in climbers who are unacclimatized.

  4. First light at the HAWC high altitude TeV gamma ray detector in Mexico

    NASA Astrophysics Data System (ADS)

    Fiorino, Daniel

    2012-03-01

    The High Altitude Water Cherenkov (HAWC) Observatory -- currently under construction at 4100m altitude at Pico de Orizaba in Mexico -- is a high duty cycle, large field of view detector for gamma rays at TeV energies. The HAWC Observatory will locate and provide spectra for extended and point sources of TeV gamma rays, probe the cosmic ray anisotropy, search for gamma ray bursts, and set limits on extragalactic background light. Data taking at our smaller test array (VAMOS) is currently under way. I will present results of a first study of several months of VAMOS data, including a first skymap, performance tests, and a search for the shadow of the moon in cosmic rays.

  5. Glycolytic intermediates and adenosine phosphates in rat liver at high altitude /3,800 m/.

    NASA Technical Reports Server (NTRS)

    Cipriano, L. F.; Pace, N.

    1973-01-01

    Liver tissue obtained from adult rats exposed to 3800 m altitude for intervals ranging from 1.5 hr to 63 days was examined by enzymatic analysis. During the first 3 hr of exposure, an immediate decrease in rephosphorylation of high-energy phosphates led to reduced glycogenesis and eventual pileup of AMP, pyruvate, fructose 1,6-diphosphate, glucose 6-phosphate, and glucose. This was accompanied by a reduction of pentose phosphate pathway activity. After 3 to 6 hr, a secondary adjustment of substrate concentrations occurred along with the apparent facilitation of phosphofructokinase. This secondary adjustment appears to increase anaerobic production of ATP and represents a significant intracellular contribution to the acclimatization process at high altitude.

  6. Platelet count and adhesiveness on induction to high altitude by air and road

    NASA Astrophysics Data System (ADS)

    Sharma, S. C.

    1982-09-01

    Platelet count and adhesiveness (PA) were estimated in 87 normal lowlanders at sea level. They were randomly divided in three groups. Group A was taken to 3 660 m by air, group B by rapid road ascent and group C by road after acclimatisation enroute. Estimations were repeated serially during stay at high altitude and then on return to sea level. The subjects were divided into “symptomatic” and “asymptomatic” groups based on their score on a symptom score chart. Some subjects of the air induced group (A) developed significant symptoms and showed a significant rise in PA on days 2 and 10 of exposure. Remaining subjects of group A and all subjects of road inducted group (B and C) remained asymptomatic and showed no change in PA. No significant change in the platelet counts in any of the lowlanders was noted on exposure to high altitude. The significance of these findings is discussed.

  7. Contribution of Neutron Beta Decay to Radiation Belt Pumping from High Altitude Nuclear Explosion

    SciTech Connect

    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 the contribution of

  8. Effects of Test Cell Recirculation on High-Bypass Turbofan Engines during Simulated Altitude Tests

    DTIC Science & Technology

    1986-08-01

    methods used to describe and correct for test cell recirculation have led to this investigation, which is in line with the objectives previously stated...between pressure profiles on the cell wall and those on the model surfaces, which is in line with previous observations. Removal of the diffuser...AEDC-TR-85-55 , , . ’ . . . .L Effects of Test Cell Recirculation on High-Bypass Turbofan Engines During Simulated Altitude Tests OCT 0 9

  9. Studies in the Lake Ontario Basin using ERTS-1 and high altitude data

    NASA Technical Reports Server (NTRS)

    Falconer, A.; Collins, S. H.; Dickinson, W. T.; Protz, R.; Bukata, R. P.; Thomson, K. P. B.; Harris, G. P.; Howarth, P. J.

    1973-01-01

    Studies in the Lake Ontario Basin are designed to provide input for models of river basin discharge and macro-scale features of lake circulation. Lake studies appear to require high altitude imagery to record the dynamic features of Lake Ontario so that ERTS-1 data may be interpreted. Land area studies require input of soil moisture, land use and soil-sediment-geomorphology measurements some of which appear to be available, on a regional scale from ERTS-1 products.

  10. On the HEMP (high-altitude electromagnetic pulse) environment for protective relays

    SciTech Connect

    Thomas, D.E.; Wiggins, C.M.; Salas, T.M. ); Barnes, P.R. )

    1990-01-01

    An assessment of the transient environment for protective relays produced by high-altitude electromagnetic pulse (HEMP) events is presented in this paper. Several mechanisms for coupling of HEMP to relay terminals are used to develop estimates of possible HEMP threats to relays. These predicted relay responses to HEMP events are compared to measured data on a solid state based relay's impulse strength. 12 refs., 13 figs., 3 tabs.

  11. High altitude perspective. [cost-reimbursable services using NASA U-2 aircraft

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The capabilities of the NASA Ames Center U-2 aircraft for research or experimental programs are described for such areas as Earth resources inventories; remote sensing data interpretation, electronic sensor research and development; satellite investigative support; stratospheric gas studies; and astronomy and astrophysics. The availability of this aircraft on a cost-reimbursable basis for use in high-altitude investigations that cannot be performed by the private sector is discussed.

  12. The Italian Spacegate: Study and innovative approaches to future generation transportation based on High Altitude Flight

    NASA Astrophysics Data System (ADS)

    Santoro, Francesco; Bellomo, Alessandro; Bolle, Andrea; Vittori, Roberto

    2014-08-01

    This paper summarizes the results of the pre-feasibility studies carried out in 2012 on the concept of sub orbital and hypersonic, high altitude flight in support of future generation transportation. Currently, while the High Altitude Flight is mostly instrumental to touristic purposes and emphasizes the so