Reduced oxygen at high altitude limits maximum size.
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).
Water Quality Assessment and Total Maximum Daily Loads Information (ATTAINS)
U.S. Environmental Protection Agency — The Water Quality Assessment TMDL Tracking And Implementation System (ATTAINS) stores and tracks state water quality assessment decisions, Total Maximum Daily Loads...
Radiation pressure acceleration: The factors limiting maximum attainable ion energy
Energy Technology Data Exchange (ETDEWEB)
Bulanov, S. S.; Esarey, E.; Schroeder, C. B. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Bulanov, S. V. [KPSI, National Institutes for Quantum and Radiological Science and Technology, Kizugawa, Kyoto 619-0215 (Japan); A. M. Prokhorov Institute of General Physics RAS, Moscow 119991 (Russian Federation); Esirkepov, T. Zh.; Kando, M. [KPSI, National Institutes for Quantum and Radiological Science and Technology, Kizugawa, Kyoto 619-0215 (Japan); Pegoraro, F. [Physics Department, University of Pisa and Istituto Nazionale di Ottica, CNR, Pisa 56127 (Italy); Leemans, W. P. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Physics Department, University of California, Berkeley, California 94720 (United States)
2016-05-15
Radiation pressure acceleration (RPA) is a highly efficient mechanism of laser-driven ion acceleration, with near complete transfer of the laser energy to the ions in the relativistic regime. However, there is a fundamental limit on the maximum attainable ion energy, which is determined by the group velocity of the laser. The tightly focused laser pulses have group velocities smaller than the vacuum light speed, and, since they offer the high intensity needed for the RPA regime, it is plausible that group velocity effects would manifest themselves in the experiments involving tightly focused pulses and thin foils. However, in this case, finite spot size effects are important, and another limiting factor, the transverse expansion of the target, may dominate over the group velocity effect. As the laser pulse diffracts after passing the focus, the target expands accordingly due to the transverse intensity profile of the laser. Due to this expansion, the areal density of the target decreases, making it transparent for radiation and effectively terminating the acceleration. The off-normal incidence of the laser on the target, due either to the experimental setup, or to the deformation of the target, will also lead to establishing a limit on maximum ion energy.
Cardiovascular Effects of Altitude on Performance Athletes.
Shah, Ankit B; Coplan, Neil
Altitude plays an important role in cardiovascular performance and training for athletes. Whether it is mountaineers, skiers, or sea-level athletes trying to gain an edge by training or living at increased altitude, there are many potential benefits and harms of such endeavors. Echocardiographic studies done on athletes at increased altitude have shown evidence for right ventricular dysfunction and pulmonary hypertension, but no change in left ventricular ejection fraction. In addition, 10% of athletes are susceptible to pulmonary hypertension and high-altitude pulmonary edema. Some studies suggest that echocardiography may be able to identify athletes susceptible to high-altitude pulmonary edema prior to competing or training at increased altitudes. Further research is needed on the long-term effects of altitude training, as repeated, transient episodes of pulmonary hypertension and right ventricular dysfunction may have long-term implications. Current literature suggests that performance athletes are not at higher risk for ventricular arrhythmias when training or competing at increased altitudes. For sea-level athletes, the optimal strategy for attaining the benefits while minimizing the harms of altitude training still needs to be clarified, although-for now-the "live high, train low" approach appears to have the most rationale.
Altitude and endurance training.
Rusko, Heikki K; Tikkanen, Heikki O; Peltonen, Juha E
2004-10-01
The benefits of living and training at altitude (HiHi) for an improved altitude performance of athletes are clear, but controlled studies for an improved sea-level performance are controversial. The reasons for not having a positive effect of HiHi include: (1) the acclimatization effect may have been insufficient for elite athletes to stimulate an increase in red cell mass/haemoglobin mass because of too low an altitude (altitude training period (training effect at altitude may have been compromised due to insufficient training stimuli for enhancing the function of the neuromuscular and cardiovascular systems; and (3) enhanced stress with possible overtraining symptoms and an increased frequency of infections. Moreover, the effects of hypoxia in the brain may influence both training intensity and physiological responses during training at altitude. Thus, interrupting hypoxic exposure by training in normoxia may be a key factor in avoiding or minimizing the noxious effects that are known to occur in chronic hypoxia. When comparing HiHi and HiLo (living high and training low), it is obvious that both can induce a positive acclimatization effect and increase the oxygen transport capacity of blood, at least in 'responders', if certain prerequisites are met. The minimum dose to attain a haematological acclimatization effect is > 12 h a day for at least 3 weeks at an altitude or simulated altitude of 2100-2500 m. Exposure to hypoxia appears to have some positive transfer effects on subsequent training in normoxia during and after HiLo. The increased oxygen transport capacity of blood allows training at higher intensity during and after HiLo in subsequent normoxia, thereby increasing the potential to improve some neuromuscular and cardiovascular determinants of endurance performance. The effects of hypoxic training and intermittent short-term severe hypoxia at rest are not yet clear and they require further study.
Kimble, Michael C.; White, Ralph E.
1991-01-01
A mathematical model of a hydrogen/oxygen alkaline fuel cell is presented that can be used to predict the polarization behavior under various power loads. The major limitations to achieving high power densities are indicated and methods to increase the maximum attainable power density are suggested. The alkaline fuel cell model describes the phenomena occurring in the solid, liquid, and gaseous phases of the anode, separator, and cathode regions based on porous electrode theory applied to three phases. Fundamental equations of chemical engineering that describe conservation of mass and charge, species transport, and kinetic phenomena are used to develop the model by treating all phases as a homogeneous continuum.
Usefulness of training camps at high altitude for well-trained adolescents
Directory of Open Access Journals (Sweden)
Jiří Suchý
2015-03-01
Full Text Available Objective: Opinions on the suitability of sports training at altitudes of 1800-2200 m above sea level (ASL for increasing performance in youth are not unanimous. The objective of this study was to test the influence of a ten day altitude training camp on performance in well-trained adolescent cross-country skiers. Methods: A running test of 3 × 2 km (aerobic, anaerobic and critical intensity was used with a rest interval of 10 minutes. The test was performed 4 times - an initial test at a lowland (900 m ASL prior to departure for altitude, two tests at altitude (1850 m ASL, a final test ten days after returning to lower altitudes. The aerobic, anaerobic and critical load intensities were set by graded a load test. For all individual tests, the participants maintained the same heart rate individually defined for the various segments using a heart rate monitor. Changes in speed between the tests were compared. The body's internal response was also monitored by the concentration of lactate (2 and 8 minutes after each exertion. Participants: Well-trained adolescent cross-country skiers (N = 11, age: 14.4 ± 1.2 years, weight: 54.4 ± 8.6 kg, height: 170 ± 7 cm, fat: 13 ± 2.6%. Results: The average times attained in the first altitude test for aerobic and anaerobic load were higher (p < .05 than in the entry test at low altitude. In the second altitude test the average times for all intensities were significantly (p < .05 higher than in the first altitude test. In the tests after returning to the lower altitudes the times attained for all intensities were on average higher than at altitude. The average lactate concentration levels following the various intensities were similar (p > .05. The dynamics of the cool-down monitored via the lactate value at the eighth minute after completing the relevant segment showed that at altitude the adolescents cooled down significantly (p < .05 slower rate following the aerobic and anaerobic intensity than at
Using Elementary Mechanics to Estimate the Maximum Range of ICBMs
Amato, Joseph
2018-04-01
North Korea's development of nuclear weapons and, more recently, intercontinental ballistic missiles (ICBMs) has added a grave threat to world order. The threat presented by these weapons depends critically on missile range, i.e., the ability to reach North America or Europe while carrying a nuclear warhead. Using the limited information available from near-vertical test flights, how do arms control experts estimate the maximum range of an ICBM? The purpose of this paper is to show, using mathematics and concepts appropriate to a first-year calculus-based mechanics class, how a missile's range can be estimated from the (observable) altitude attained during its test flights. This topic—while grim—affords an ideal opportunity to show students how the application of basic physical principles can inform and influence public policy. For students who are already familiar with Kepler's laws, it should be possible to present in a single class period.
Shekhar, M. S.; Devi, Usha; Dash, S. K.; Singh, G. P.; Singh, Amreek
2018-04-01
The current trends in diurnal temperature range, maximum temperature, minimum temperature, mean temperature, and sun shine hours over different ranges and altitudes of Western Himalaya during winter have been studied. Analysis of 25 years of data shows an increasing trend in diurnal temperature range over all the ranges and altitudes of Western Himalaya during winter, thereby confirming regional warming of the region due to present climate change and global warming. Statistical studies show significant increasing trend in maximum temperature over all the ranges and altitudes of Western Himalaya. Minimum temperature shows significant decreasing trend over Pir Panjal and Shamshawari range and significant increasing trend over higher altitude of Western Himalaya. Similarly, sunshine hours show significant decreasing trend over Karakoram range. There exists strong positive correlation between diurnal temperature range and maximum temperature for all the ranges and altitudes of Western Himalaya. Strong negative correlation exists between diurnal temperature range and minimum temperature over Shamshawari and Great Himalaya range and lower altitude of Western Himalaya. Sunshine hours show strong positive correlation with diurnal temperature range over Pir Panjal and Great Himalaya range and lower and higher altitudes.
Chernobyl radioactivity and high altitude air-particulate monitoring at Islamabad
International Nuclear Information System (INIS)
Bhatti, M.S.; Ihsanullah; Shafiq, M.; Perveen, N.; Orfi, S.D.
1987-11-01
High altitude sampling of air particulates for radioactivity monitoring was conducted at Islamabad after the CHERNOBYL accident. Smears from aeroplanes flying at varying altitudes were collected and analysed for fresh fission products mainly gamma emitters e.g. Ru-103 and Cs-137 etc. The maximum radioactivity observed was of the order of 15Bq/sample for Ru-103 and 9Bq/sample for Cs-137 respectively. The study was purely qualitative in nature indicated the presence of fresh fission radioactivity at high altitudes over Islamabad. For quantitative measurements at high altitudes sophisticated instrumentation/procedure needs to be adopted. (author)
A Comparitive Analysis of the Influence of Weather on the Flight Altitudes of Birds.
Shamoun-Baranes, Judy; van Loon, Emiel; van Gasteren, Hans; van Belle, Jelmer; Bouten, Willem; Buurma, Luit
2006-01-01
Birds pose a serious risk to flight safety worldwide. A Bird Avoidance Model (BAM) is being developed in the Netherlands to reduce the risk of bird aircraft collisions. In order to develop a temporally and spatially dynamic model of bird densities, data are needed on the flight-altitude distribution of birds and how this is influenced by weather. This study focuses on the dynamics of flight altitudes of several species of birds during local flights over land in relation to meteorological conditions.We measured flight altitudes of several species in the southeastern Netherlands using tracking radar during spring and summer 2000. Representatives of different flight strategy groups included four species: a soaring species (buzzard ), an obligatory aerial forager (swift Apus apus), a flapping and gliding species (blackheaded gull Larus ridibundus), and a flapping species (starling Sturnus vulgaris).Maximum flight altitudes varied among species, during the day and among days. Weather significantly influenced the flight altitudes of all species studied. Factors such as temperature, relative humidity, atmospheric instability, cloud cover, and sea level pressure were related to flight altitudes. Different combinations of factors explained 40% 70% of the variance in maximum flight altitudes. Weather affected flight strategy groups differently. Compared to flapping species, buzzards and swifts showed stronger variations in maximum daily altitude and f lew higher under conditions reflecting stronger thermal convection. The dynamic vertical distributions of birds are important for risk assessment and mitigation measures in flight safety as well as wind turbine studies.
High-Altitude Illnesses: Physiology, Risk Factors, Prevention, and Treatment
Directory of Open Access Journals (Sweden)
Andrew T. Taylor
2011-01-01
Full Text Available High-altitude illnesses encompass the pulmonary and cerebral syndromes that occur in non-acclimatized individuals after rapid ascent to high altitude. The most common syndrome is acute mountain sickness (AMS which usually begins within a few hours of ascent and typically consists of headache variably accompanied by loss of appetite, nausea, vomiting, disturbed sleep, fatigue, and dizziness. With millions of travelers journeying to high altitudes every year and sleeping above 2,500 m, acute mountain sickness is a wide-spread clinical condition. Risk factors include home elevation, maximum altitude, sleeping altitude, rate of ascent, latitude, age, gender, physical condition, intensity of exercise, pre-acclimatization, genetic make-up, and pre-existing diseases. At higher altitudes, sleep disturbances may become more profound, mental performance is impaired, and weight loss may occur. If ascent is rapid, acetazolamide can reduce the risk of developing AMS, although a number of high-altitude travelers taking acetazolamide will still develop symptoms. Ibuprofen can be effective for headache. Symptoms can be rapidly relieved by descent, and descent is mandatory, if at all possible, for the management of the potentially fatal syndromes of high-altitude pulmonary and cerebral edema. The purpose of this review is to combine a discussion of specific risk factors, prevention, and treatment options with a summary of the basic physiologic responses to the hypoxia of altitude to provide a context for managing high-altitude illnesses and advising the non-acclimatized high-altitude traveler.
Numerical simulation of the ionization effects of low- and high-altitude nuclear explosions
International Nuclear Information System (INIS)
Zhao Zhengyu; Wang Xiang
2007-01-01
Low-altitude and high-altitude nuclear explosions are sources of intensive additional ionization in ionosphere. In this paper, in terms of the ionization equilibrium equation system and the equation of energy deposition of radiation in atmosphere, and considering the influence of atmosphere, the temporal and spatial distribution of ionization effects caused by atmospheric nuclear detonation are investigated. The calculated results show that the maximum of additional free electron density produced by low-altitude nuclear explosion is greater than that by the high-altitude nuclear burst. As to the influence of instant nuclear radiation, there is obvious difference between the low-altitude and the high-altitude explosions. The influence range and the continuance time caused by delayed nuclear radiation is less for the low-altitude nuclear detonation than that for the high-altitude one. (authors)
Robust Maximum Association Estimators
A. Alfons (Andreas); C. Croux (Christophe); P. Filzmoser (Peter)
2017-01-01
textabstractThe maximum association between two multivariate variables X and Y is defined as the maximal value that a bivariate association measure between one-dimensional projections αX and αY can attain. Taking the Pearson correlation as projection index results in the first canonical correlation
Neumayr, Günther; Fries, Dietmar; Mittermayer, Markus; Humpeler, Egon; Klingler, Anton; Schobersberger, Wolfgang; Spiesberger, Reinhard; Pokan, Rochus; Schmid, Peter; Berent, Robert
2014-09-01
Physical activity is a cornerstone in therapy for patients with metabolic syndrome. Walking and hiking in a mountain scenery represents an ideal approach to make them move. The Austrian Moderate Altitude Study (AMAS) 2000 main study is a randomized controlled trial to investigate the cardiovascular effects of hiking at moderate altitude on patients with metabolic syndrome compared with a control group at low altitude, to assess a potential altitude-specific effect. Seventy-one male patients with metabolic syndrome were randomly assigned to a moderate altitude group (at 1700 m), with 36 participants, or to a low altitude group (at 200 m), with 35 participants. The 3-week vacation program included 12 hiking tours (4 per week, average duration 2.5 hours, intensity 55% to 65% of heart rate maximum). Physical parameters, performance capacity, 24-hour blood pressure, and heart rate profiles were obtained before, during, and after the stay. In both groups, we found a significant mean weight loss of -3.13 kg; changes in performance capacity were minor. Systolic, diastolic, and mean arterial pressures and circadian heart rate profiles were significantly reduced in both groups, with no differences between them. Consequently, the pressure-rate product was reduced as well. All study participants tolerated the vacation well without any adverse events. A 3-week hiking vacation at moderate or low altitude is safe for patients with metabolic syndrome and provides several improvements in their cardiovascular parameters. The cardiovascular benefits achieved are more likely to be the result of regular physical activity than the altitude-specific effect of a mountain environment. Copyright © 2014 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.
Directory of Open Access Journals (Sweden)
Campos, Néstor
2015-12-01
Full Text Available The main aim of this research was to reconstruct the LLGM (local last glacial maximum, 1955 and 2007 glacial phases on the South West slope of Nevado Coropuna to obtain valuable information on the changes that have occurred and analyze the glacier evolution. For this purpose the ELA (Equilibrium Line Altitude indicator has been used as a reference, with the AABR (Area x Altitude Balance Ratio method, based on the principle of weighting the mass balance according to the distance above or below the ELA of that area. An ELA of 4762 m was obtained for the LLGM, 5779 m for 1955 and 5850 m for 2007, implying a vertical shift of 1088 m from the LLGM to 2007 and of 71 m from 1955 to 2007. The total glaciated surface was reduced by 21.5% between 1955 and 2007 and the temperature shift from LLGM to 2007 was 9.13 ºC (0.0091ºC/m. The ice of glaciers makes them valuable for climate research, this method offers quantitative information and the analysis of this data may contribute to research into climate change and climatic trends for future predictions.El principal objetivo de esta investigación es reconstruir las fases glaciares del Último Máximo Glaciar Local (LLGM, 1955 y 2007 en la vertiente Suroeste del Nevado Coropuna para obtener información sobre los cambios ocurridos y analizar la evolución glaciar. Para este propósito el indicador de la altitud de la línea de equilibrio glaciar (ELA ha sido utilizado como referencia, calculado con el método AABR (Area x Altitude Balance Ratio, basado en el principio de ponderación del balance de masa en función de la distancia por encima o debajo de la ELA de esa área. Se obtuvo una ELA de 4762 m para el LLGM, 5779 m para 1955 y 5850 m para 2007, lo que implica una variación de 1088 m desde el LLGM hasta el 2007 y 71 m desde 1955 hasta 2007. La superficie total glaciada se redujo un 21,5% entre 1955 y 2007 y la variación de temperatura desde el LLGM hasta 2007 fue de 9,13 ºC (0,0091ºC/m. El hielo
Directory of Open Access Journals (Sweden)
S. Vignesh
2017-04-01
Full Text Available Flow based Erosion – corrosion problems are very common in fluid handling equipments such as propellers, impellers, pumps in warships, submarine. Though there are many coating materials available to combat erosion–corrosion damage in the above components, iron based amorphous coatings are considered to be more effective to combat erosion–corrosion problems. High velocity oxy-fuel (HVOF spray process is considered to be a better process to coat the iron based amorphous powders. In this investigation, iron based amorphous metallic coating was developed on 316 stainless steel substrate using HVOF spray technique. Empirical relationships were developed to predict the porosity and micro hardness of iron based amorphous coating incorporating HVOF spray parameters such as oxygen flow rate, fuel flow rate, powder feed rate, carrier gas flow rate, and spray distance. Response surface methodology (RSM was used to identify the optimal HVOF spray parameters to attain coating with minimum porosity and maximum hardness.
Generalized math model for simulation of high-altitude balloon systems
Nigro, N. J.; Elkouh, A. F.; Hinton, D. E.; Yang, J. K.
1985-01-01
Balloon systems have proved to be a cost-effective means for conducting research experiments (e.g., infrared astronomy) in the earth's atmosphere. The purpose of this paper is to present a generalized mathematical model that can be used to simulate the motion of these systems once they have attained float altitude. The resulting form of the model is such that the pendulation and spin motions of the system are uncoupled and can be analyzed independently. The model is evaluated by comparing the simulation results with data obtained from an actual balloon system flown by NASA.
Energy Technology Data Exchange (ETDEWEB)
Suzuki, H.; Hashidate, M. [National Aerospace Laboratory, Tokyo (Japan)
1995-11-01
An altitude of about 20 km has the atmospheric density too dilute for common aircraft, and the air resistance too great for satellites. Attention has been drawn in recent years on a high-altitude long-endurance unmanned vehicle that flies at this altitude for a long period of time to serve as a wave relaying base and perform traffic control. Therefore, a development was made on a flight simulation program to evaluate and discuss the guidance and control laws for the high-altitude unmanned vehicle. Equations of motion were derived for three-dimensional six freedom and three-dimensional three freedom. Aerodynamic characteristics of an unmanned vehicle having a Rectenna wing were estimated, and formulation was made according to the past research results on data of winds that the unmanned vehicle is anticipated to encounter at an altitude of 20 km. Noticing the inside of a horizontal plane, a proposal was given on a guidance law that follows a given path. A flight simulation was carried out to have attained a prospect that the unmanned vehicle may be enclosed in a limited space even if the vehicle is encountered with a relatively strong wind. 18 refs., 20 figs., 1 tab.
[Physiological aspects of altitude training and the use of altitude simulators].
Ranković, Goran; Radovanović, Dragan
2005-01-01
Altitude training in various forms is widely practiced by athletes and coaches in an attempt to improve sea level endurance. Training at high altitude may improve performance at sea level through altitude acclimatisation, which improves oxygen transport and/or utilisation, or through hypoxia, which intensifies the training stimulus. This basic physiological aspect allows three training modalities: live high and train high (classic high-altitude training), live low and train high (training through hypoxia), and live high and train low (the new trend). In an effort to reduce the financial and logistical challenges of travelling to high-altitude training sites, scientists and manufactures have developed artificial high-altitude environments, which simulate the hypoxic conditions of moderate altitude (2000-3000 meters). Endurance athletes from many sports have recently started using nitrogen environments, or hypoxic rooms and tents as part of their altitude training programmes. The results of controlled studies on these modalities of high-altitude training, their practical approach, and ethics are summarised.
Physiological aspects of altitude training and the use of altitude simulators
Directory of Open Access Journals (Sweden)
Ranković Goran
2005-01-01
Full Text Available Altitude training in various forms is widely practiced by athletes and coaches in an attempt to improve sea level endurance. Training at high altitude may improve performance at sea level through altitude acclimatization, which improves oxygen transport and/or utilization, or through hypoxia, which intensifies the training stimulus. This basic physiological aspect allows three training modalities: live high and train high (classic high-altitude training, live low and train high (training through hypoxia, and live high and train low (the new trend. In an effort to reduce the financial and logistical challenges of traveling to high-altitude training sites, scientists and manufactures have developed artificial high-altitude environments, which simulate the hypoxic conditions of moderate altitude (2000-3000 meters. Endurance athletes from many sports have recently started using nitrogen environments, or hypoxic rooms and tents as part of their altitude training programmes. The results of controlled studies on these modalities of high-altitude training, their practical approach, and ethics are summarized.
International Nuclear Information System (INIS)
Kulish, u.P.; Galkina, K.A.; Karabekova, Z.K.; Kudryavtsev, V.I.; Gudi, T.P.
1984-01-01
An attempt is made to clarify possibilities of high-altitude conditions use in clinics to restore hematological indices deteriorating as a result of antitumoral radiation or cytostatic therapy. Using conventional methods the content of hemoglobin, the number of erythrocytes and leukocytes, leukocytic formula in the blood of patients have been determined. Using the method of hemocultures the ability of the blood serum to affect leukocyte migration of practically healthy people (donors) has been studied and by the method of amperometric titration the content of SH-groups in the blood is determined. In patients examined under high-altitude conditions the content of hemoglobin and the number of erythrocytes in blood increased, the level of total SH-groups of blood also grew. Blood serum of patients with the expressed lymphocytopenia instead of suppressing effect on leukocyte migration, observed under low-altitude conditions (Frunze), under high-altitude conditions attained the ability to increase leukocyte migration. The conclusion is made that high-altitude hypoxia is a positive factor in the treatment of radiation and cytostatic lymphopenias in cancer patients
Low-altitude trapped protons at the geomagnetic equator
Guzik, T. G.; Miah, M. A.; Mitchell, J. M.; Wefel, J. P.
1989-01-01
Geomagnetically trapped protons in the 0.6- to 9-MeV energy range were measured at latitudes near the geomagnetic equator by the Phoenix 1 experiment on board the S81-1 mission from May to November 1982. The protons show a distribution in latitude along the line of minimum magnetic field strength with a full width at half maximum of about 10 deg but with no appreciable longitudinal variation. Between 170 and 290 Km the peak proton flux shows a fifth-power altitude dependence, in contrast to previous measurements at higher altitudes, possibly demonstrating source attenuation. The efficiency of the telescope is calculated as a function of particle pitch angle and used to investigate the time dependence (1969-1982) of the intensity.
Directory of Open Access Journals (Sweden)
Dwitya Elvira
2015-05-01
Full Text Available AbstrakHigh-altitude illness (HAI merupakan sekumpulan gejala paru dan otak yang terjadi pada orang yang baru pertama kali mendaki ke ketinggian. HAI terdiri dari acute mountain sickness (AMS, high-altitude cerebral edema (HACE dan high-altitude pulmonary edema (HAPE. Tujuan tinjauan pustaka ini adalah agar dokter dan wisatawan memahami risiko, tanda, gejala, dan pengobatan high-altitude illness. Perhatian banyak diberikan terhadap penyakit ini seiring dengan meningkatnya popularitas olahraga ekstrim (mendaki gunung tinggi, ski dan snowboarding dan adanya kemudahan serta ketersediaan perjalanan sehingga jutaan orang dapat terpapar bahaya HAI. Di Pherice, Nepal (ketinggian 4343 m, 43% pendaki mengalami gejala AMS. Pada studi yang dilakukan pada tempat wisata di resort ski Colorado, Honigman menggambarkan kejadian AMS 22% pada ketinggian 1850 m sampai 2750 m, sementara Dean menunjukkan 42% memiliki gejala pada ketinggian 3000 m. Aklimatisasi merupakan salah satu tindakan pencegahan yang dapat dilakukan sebelum pendakian, selain beberapa pengobatan seperti asetazolamid, dexamethasone, phosopodiestrase inhibitor, dan ginko biloba.Kata kunci: high-altitude illness, acute mountain sickness, edema cerebral, pulmonary edema AbstractHigh-altitude illness (HAI is symptoms of lung and brain that occurs in people who first climb to altitude. HAI includes acute mountain sickness (AMS, high-altitude cerebral edema (HACE and high altitude pulmonary edema (HAPE. The objective of this review was to understand the risks, signs, symptoms, and treatment of high-altitude illness. The attention was given to this disease due to the rising popularity of extreme sports (high mountain climbing, skiing and snowboarding and the ease and availability of the current travelling, almost each year, millions of people could be exposed to the danger of HAI. In Pherice, Nepal (altitude 4343 m, 43% of climbers have symptoms of AMS. Furthermore, in a study conducted at sites in
Friedmann-Bette, B
2008-08-01
For more than 40 years, the effects of classical altitude training on sea-level performance have been the subject of many scientific investigations in individual endurance sports. To our knowledge, no studies have been performed in team sports like football. Two well-controlled studies showed that living and training at an altitude of >or=1800-2700 m for 3-4 weeks is superior to equivalent training at sea level in well-trained athletes. Most of the controlled studies with elite athletes did not reveal such an effect. However, the results of some uncontrolled studies indicate that sea-level performance might be enhanced after altitude training also in elite athletes. Whether hypoxia provides an additional stimulus for muscular adaptation, when training is performed with equal intensity compared with sea-level training is not known. There is some evidence for an augmentation of total hemoglobin mass after classical altitude training with duration >or=3 weeks at an altitude >or=2000 m due to altitude acclimatization. Considerable individual variation is observed in the erythropoietic response to hypoxia and in the hypoxia-induced reduction of aerobic performance capacity during training at altitude, both of which are thought to contribute to inter-individual variation in the improvement of sea-level performance after altitude training.
Low-altitude trapped protons at the geomagnetic equator
International Nuclear Information System (INIS)
Guzik, T.G.; Miah, M.A.; Mitchell, J.W.; Wefel, J.P.
1989-01-01
Geomagnetically trapped protons in the 0.6- to 9-MeV energy range were measured at latitudes near the geomagnetic equator by the Phoenix 1 experiment on board the S81-1 mission from May to November 1982. The protons show a distribution in latitude along the line of minimum magnetic field strength with a full width at half maximum of ∼10 0 but with no appreciable longitudinal variation. Between 170 and 290 km the peak proton flux shows a fifth-power altitude dependence, in contrast to previous measurements at higher altitudes, possibly demonstrating source attenuation. The efficiency of the telescope is calculated as a function of particle pitch angle and used to investigate the time dependence (1969--1982) of the intensity. copyright American Geophysical Union 1989
Physiological aspects of altitude training and the use of altitude simulators
Ranković Goran; Radovanović Dragan
2005-01-01
Altitude training in various forms is widely practiced by athletes and coaches in an attempt to improve sea level endurance. Training at high altitude may improve performance at sea level through altitude acclimatization, which improves oxygen transport and/or utilization, or through hypoxia, which intensifies the training stimulus. This basic physiological aspect allows three training modalities: live high and train high (classic high-altitude training), live low and train high (training thr...
14 CFR 31.19 - Performance: Uncontrolled descent.
2010-01-01
... single failure of the heater assembly, fuel cell system, gas value system, or maneuvering vent system, or from any single tear in the balloon envelope between tear stoppers: (1) The maximum vertical velocity attained. (2) The altitude loss from the point of failure to the point at which maximum vertical velocity...
Khodaee, Morteza; Grothe, Heather L; Seyfert, Jonathan H; VanBaak, Karin
2016-01-01
Athletes at different skill levels perform strenuous physical activity at high altitude for a variety of reasons. Multiple team and endurance events are held at high altitude and may place athletes at increased risk for developing acute high altitude illness (AHAI). Training at high altitude has been a routine part of preparation for some of the high level athletes for a long time. There is a general belief that altitude training improves athletic performance for competitive and recreational athletes. A review of relevant publications between 1980 and 2015 was completed using PubMed and Google Scholar. Clinical review. Level 3. AHAI is a relatively uncommon and potentially serious condition among travelers to altitudes above 2500 m. The broad term AHAI includes several syndromes such as acute mountain sickness (AMS), high altitude pulmonary edema (HAPE), and high altitude cerebral edema (HACE). Athletes may be at higher risk for developing AHAI due to faster ascent and more vigorous exertion compared with nonathletes. Evidence regarding the effects of altitude training on athletic performance is weak. The natural live high, train low altitude training strategy may provide the best protocol for enhancing endurance performance in elite and subelite athletes. High altitude sports are generally safe for recreational athletes, but they should be aware of their individual risks. Individualized and appropriate acclimatization is an essential component of injury and illness prevention.
March, Rod S.
2003-01-01
The 1996 measured winter snow, maximum winter snow, net, and annual balances in the Gulkana Glacier Basin were evaluated on the basis of meteorological, hydrological, and glaciological data. Averaged over the glacier, the measured winter snow balance was 0.87 meter on April 18, 1996, 1.1 standard deviation below the long-term average; the maximum winter snow balance, 1.06 meters, was reached on May 28, 1996; and the net balance (from August 30, 1995, to August 24, 1996) was -0.53 meter, 0.53 standard deviation below the long-term average. The annual balance (October 1, 1995, to September 30, 1996) was -0.37 meter. Area-averaged balances were reported using both the 1967 and 1993 area altitude distributions (the numbers previously given in this abstract use the 1993 area altitude distribution). Net balance was about 25 percent less negative using the 1993 area altitude distribution than the 1967 distribution. Annual average air temperature was 0.9 degree Celsius warmer than that recorded with the analog sensor used since 1966. Total precipitation catch for the year was 0.78 meter, 0.8 standard deviations below normal. The annual average wind speed was 3.5 meters per second in the first year of measuring wind speed. Annual runoff averaged 1.50 meters over the basin, 1.0 standard deviation below the long-term average. Glacier-surface altitude and ice-motion changes measured at three index sites document seasonal ice-speed and glacier-thickness changes. Both showed a continuation of a slowing and thinning trend present in the 1990s. The glacier terminus and lower ablation area were defined for 1996 with a handheld Global Positioning System survey of 126 locations spread out over about 4 kilometers on the lower glacier margin. From 1949 to 1996, the terminus retreated about 1,650 meters for an average retreat rate of 35 meters per year.
Size dependence of efficiency at maximum power of heat engine
Izumida, Y.; Ito, N.
2013-01-01
We perform a molecular dynamics computer simulation of a heat engine model to study how the engine size difference affects its performance. Upon tactically increasing the size of the model anisotropically, we determine that there exists an optimum size at which the model attains the maximum power for the shortest working period. This optimum size locates between the ballistic heat transport region and the diffusive heat transport one. We also study the size dependence of the efficiency at the maximum power. Interestingly, we find that the efficiency at the maximum power around the optimum size attains a value that has been proposed as a universal upper bound, and it even begins to exceed the bound as the size further increases. We explain this behavior of the efficiency at maximum power by using a linear response theory for the heat engine operating under a finite working period, which naturally extends the low-dissipation Carnot cycle model [M. Esposito, R. Kawai, K. Lindenberg, C. Van den Broeck, Phys. Rev. Lett. 105, 150603 (2010)]. The theory also shows that the efficiency at the maximum power under an extreme condition may reach the Carnot efficiency in principle.© EDP Sciences Società Italiana di Fisica Springer-Verlag 2013.
Size dependence of efficiency at maximum power of heat engine
Izumida, Y.
2013-10-01
We perform a molecular dynamics computer simulation of a heat engine model to study how the engine size difference affects its performance. Upon tactically increasing the size of the model anisotropically, we determine that there exists an optimum size at which the model attains the maximum power for the shortest working period. This optimum size locates between the ballistic heat transport region and the diffusive heat transport one. We also study the size dependence of the efficiency at the maximum power. Interestingly, we find that the efficiency at the maximum power around the optimum size attains a value that has been proposed as a universal upper bound, and it even begins to exceed the bound as the size further increases. We explain this behavior of the efficiency at maximum power by using a linear response theory for the heat engine operating under a finite working period, which naturally extends the low-dissipation Carnot cycle model [M. Esposito, R. Kawai, K. Lindenberg, C. Van den Broeck, Phys. Rev. Lett. 105, 150603 (2010)]. The theory also shows that the efficiency at the maximum power under an extreme condition may reach the Carnot efficiency in principle.© EDP Sciences Società Italiana di Fisica Springer-Verlag 2013.
Running humans attain optimal elastic bounce in their teens.
Legramandi, Mario A; Schepens, Bénédicte; Cavagna, Giovanni A
2013-01-01
In an ideal elastic bounce of the body, the time during which mechanical energy is released during the push equals the time during which mechanical energy is absorbed during the brake, and the maximal upward velocity attained by the center of mass equals the maximal downward velocity. Deviations from this ideal model, prolonged push duration and lower upward velocity, have found to be greater in older than in younger adult humans. However it is not known how similarity to the elastic bounce changes during growth and whether an optimal elastic bounce is attained at some age. Here we show that similarity with the elastic bounce is minimal at 2 years and increases with age attaining a maximum at 13-16 years, concomitant with a mirror sixfold decrease of the impact deceleration peak following collision of the foot with the ground. These trends slowly reverse during the course of the lifespan.
Hartman-Ksycińska, Anna; Kluz-Zawadzka, Jolanta; Lewandowski, Bogumił
High-altitude illness is a result of prolonged high-altitude exposure of unacclimatized individuals. The illness is seen in the form of acute mountain sickness (AMS) which if not treated leads to potentially life-threatening high altitude pulmonary oedema and high-altitude cerebral oedema. Medical problems are caused by hypobaric hypoxia stimulating hypoxia-inducible factor (HIF) release. As a result, the central nervous system, circulation and respiratory system function impairment occurs. The most important factor in AMS treatment is acclimatization, withdrawing further ascent and rest or beginning to descent; oxygen supplementation, and pharmacological intervention, and, if available, a portable hyperbaric chamber. Because of the popularity of high-mountain sports and tourism better education of the population at risk is essential.
[Arterial hypertension due to altitude].
Domej, Wolfgang; Trapp, Michael; Miggitsch, Eva Maria; Krakher, Tiziana; Riedlbauer, Rita; Roher, Peter; Schwaberger, Günther
2008-01-01
The behavior of blood pressure under hypoxic conditions depends on individual factors, altitude and duration of stay at altitude. While most humans are normotensive at higher altitudes, a few will react with moderate hypertension or hypotension. Excessive elevation of arterial blood pressure is not even to be expected below 4,000 m. Rather, several weeks' stay at higher altitude will decrease systolic and diastolic blood pressure at rest as well as during physical exertion. A high-altitude treatment for rehabilitation purposes at moderate altitude may be recommended for patients with cardio-circulatory disorders. Improvements can last several months even after returning to accustomed altitudes. Furthermore, endurance-trained hypertensive patients with pharmacologically controlled arterial blood pressure might be able to participate in mountain treks without additional health risk.
Tutte sets in graphs II: The complexity of finding maximum Tutte sets
Bauer, D.; Broersma, Haitze J.; Kahl, N.; Morgana, A.; Schmeichel, E.; Surowiec, T.
2007-01-01
A well-known formula of Tutte and Berge expresses the size of a maximum matching in a graph $G$ in terms of what is usually called the deficiency. A subset $X$ of $V(G)$ for which this deficiency is attained is called a Tutte set of $G$. While much is known about maximum matchings, less is known
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.
Training at altitude in practice.
Dick, F W
1992-10-01
There can be little doubt that training at altitude is fundamental to preparing an athlete for competition at altitude. However the value of training at altitude for competition at sea level appears on the one hand to lack total acceptance amongst sports scientists; and on the other to hold some cloak of mystery for coaches who have yet to enjoy first hand experience. The fact is that very few endurance athletes will ignore the critical edge which altitude training affords. Each fraction of a percentage of performance advantage gained through methods which are within the rules of fair play in sport, may shift the balance between failure and achievement. Moreover, there is growing support for application of training at altitude for speed-related disciplines. This paper aims to demystify the subject by dealing with practical aspects of training at altitude. Such aspects include a checklist of what should and should not be done at altitude, when to use altitude relative to target competitions, and specific training examples.
Magnetic Pair Creation Attenuation Altitude Constraints in Gamma-Ray Pulsars
Baring, Matthew; Story, Sarah
The Fermi gamma-ray pulsar database now exceeds 150 sources and has defined an important part of Fermi's science legacy, providing rich information for the interpretation of young energetic pulsars and old millisecond pulsars. Among the well established population characteristics is the common occurrence of exponential turnovers in the 1-10 GeV range. These turnovers are too gradual to arise from magnetic pair creation in the strong magnetic fields of pulsar inner magnetospheres, so their energy can be used to provide lower bounds to the typical altitude of GeV band emission. We explore such constraints due to single-photon pair creation transparency at and below the turnover energy. Our updated computations span both domains when general relativistic influences are important and locales where flat spacetime photon propagation is modified by rotational aberration effects. The altitude bounds, typically in the range of 2-5 stellar radii, provide key information on the emission altitude in radio quiet pulsars that do not possess double-peaked pulse profiles. However, the exceptional case of the Crab pulsar provides an altitude bound of around 20% of the light cylinder radius if pair transparency persists out to 350 GeV, the maximum energy detected by MAGIC. This is an impressive new physics-based constraint on the Crab's gamma-ray emission locale.
2010-07-01
... treatment wet air pollution control scrubber blowdown. Subpart J—BAT Pollutant or pollutant property Maximum...) Mixing wet air pollution control scrubber blowdown. Subpart J—BAT Pollutant or pollutant property Maximum... degree of effluent reduction attainable by the application of the best available technology economically...
Prince, William R; Mcaulay, John E
1950-01-01
An investigation of turbojet-engine thrust augmentation by means of tail-pipe burning was conducted in the NACA Lewis altitude wind tunnel. Performance data were obtained with a tail-pipe burner having a converging conical burner section installed on an axial-flow-compressor type turbojet engine over a range of simulated flight conditions and tail-pipe fuel-air ratios with a fixed-area exhaust nozzle. A maximum tail-pipe combustion efficiency of 0.86 was obtained at an altitude of 15,000 feet and a flight Mach number of 0.23. Tail-pipe burner operation was possible up to an altitude of 45,000 feet at a flight Mach number of 0.23.
Directory of Open Access Journals (Sweden)
Ubaid Yaqoob
2017-01-01
Full Text Available Ferula jaeschkeana Vatke is an important threatened medicinal plant of the Himalayan region. The present study was carried out to determine the impact of the habitat variability and altitudinal gradient on the morphological and reproductive features of the species under study. The species exhibited great variability in its morphological traits under different environmental conditions. The plants were more vigorous and taller at a low altitude site, Kashmir University Botanical Garden (KUBG while the plants of a high altitude site, Gulmarg were shorter. With increased altitude, a significant reduction in the number of umbels per flowering stem, umbellules per umbel and flowers per umbellule occurred. An increase in the number of stigma and anthers was also observed in some plants at higher altitudes. Principal component analysis (PCA revealed that the habitat of KUBG and Dachigam proved relatively better for the growth of F. jaeschkeana. Maximum resources were allocated to the growth and development of the stem followed by root tubers, leaves and inflorescence. Reproductive success of the plant species varied along the altitudinal gradient and ranged from 64% to 72%. Increasing altitude resulted in a decrease in the allocation of biomass to reproductive structures in the form of decreasing dry weight. The total resource budget per plant was maximum in low altitude Drang (572.6 ± 158.36 g and Dachigam (568.4 ± 133.42 g populations and was least in the Gulmarg population (333.4 ± 82.89 g. The reproductive effort was higher (50.83% for the high altitude Gulmarg population. The regression analysis revealed a positive correlation and predicts that plant height has a direct impact on the umbel diameter and leaf length. Our results present a detailed account on the variation of growth characteristics, reproductive success and changes in allocation patterns in relation to the environmental conditions of this valuable medicinal plant species
Food Abundance Is the Main Determinant of High-Altitude Range Use in Snub-Nosed Monkeys
Directory of Open Access Journals (Sweden)
Cyril C. Grueter
2012-01-01
Full Text Available High-altitude dwelling primates have to optimize navigating a space that contains both a vertical and horizontal component. Black-and-white or Yunnan snub-nosed monkeys (Rhinopithecus bieti are extreme by primate standards in inhabiting relatively cold subalpine temperate forests at very high altitudes where large seasonal variation in climate and food availability is expected to profoundly modulate their ranging strategies so as to ensure a positive energy balance. A “semi-nomadic” group of R. bieti was followed for 20 months in the montane Samage Forest, Baimaxueshan Nature Reserve, Yunnan, PRC, which consisted of evergreen conifers, oaks, and deciduous broadleaf trees. The aim of this study was to disentangle the effects of climate and phenology on patterns of altitudinal range use. Altitude used by the group ranged from a maximum of 3550 m in July 2007 to a minimum of 3060 m in April 2006. The proportional use of lichen, the monkeys’ staple fallback food, in the diet explained more variation in monthly use of altitudes than climatic factors and availability of flush and fruit. The abundance of lichens at high altitudes, the lack of alternative foods in winter, and the need to satisfy the monkey's basal energetic requirements explain the effect of lichenivory on use of altitudes.
Lunar Landing Training vehicle piloted by Neil Armstrong during training
1969-01-01
A Lunar Landing Training Vehicle, piloted by Astronaut Neil Armstrong, goes through a checkout flight at Ellington Air Force Base on June 16, 1969. The total duration of the lunar simulation flight was five minutes and 59 seconds. Maximum altitude attained was about 300 feet.
Endurance training at altitude.
Saunders, Philo U; Pyne, David B; Gore, Christopher J
2009-01-01
Since the 1968 Olympic Games when the effects of altitude on endurance performance became evident, moderate altitude training ( approximately 2000 to 3000 m) has become popular to improve competition performance both at altitude and sea level. When endurance athletes are exposed acutely to moderate altitude, a number of physiological responses occur that can comprise performance at altitude; these include increased ventilation, increased heart rate, decreased stroke volume, reduced plasma volume, and lower maximal aerobic power ((.)Vo(2max)) by approximately 15% to 20%. Over a period of several weeks, one primary acclimatization response is an increase in the volume of red blood cells and consequently of (.)Vo(2max). Altitudes > approximately 2000 m for >3 weeks and adequate iron stores are required to elicit these responses. However, the primacy of more red blood cells for superior sea-level performance is not clear-cut since the best endurance athletes in the world, from Ethiopia (approximately 2000 to 3000 m), have only marginally elevated hemoglobin concentrations. The substantial reduction in (.)Vo(2max) of athletes at moderate altitude implies that their training should include adequate short-duration (approximately 1 to 2 min), high-intensity efforts with long recoveries to avoid a reduction in race-specific fitness. At the elite level, athlete performance is not dependent solely on (.)Vo(2max), and the "smallest worthwhile change" in performance for improving race results is as little as 0.5%. Consequently, contemporary statistical approaches that utilize the concept of the smallest worthwhile change are likely to be more appropriate than conventional statistical methods when attempting to understand the potential benefits and mechanisms of altitude training.
Dose-response of altitude training: how much altitude is enough?
Levine, Benjamin D; Stray-Gundersen, James
2006-01-01
Altitude training continues to be a key adjunctive aid for the training of competitive athletes throughout the world. Over the past decade, evidence has accumulated from many groups of investigators that the "living high--training low" approach to altitude training provides the most robust and reliable performance enhancements. The success of this strategy depends on two key features: 1) living high enough, for enough hours per day, for a long enough period of time, to initiate and sustain an erythropoietic effect of high altitude; and 2) training low enough to allow maximal quality of high intensity workouts, requiring high rates of sustained oxidative flux. Because of the relatively limited access to environments where such a strategy can be practically applied, numerous devices have been developed to "bring the mountain to the athlete," which has raised the key issue of the appropriate "dose" of altitude required to stimulate an acclimatization response and performance enhancement. These include devices using molecular sieve technology to provide a normobaric hypoxic living or sleeping environment, approaches using very high altitudes (5,500m) for shorter periods of time during the day, and "intermittent hypoxic training" involving breathing very hypoxic gas mixtures for alternating 5 minutes periods over the course of 60-90 minutes. Unfortunately, objective testing of the strategies employing short term (less than 4 hours) normobaric or hypobaric hypoxia has failed to demonstrate an advantage of these techniques. Moreover individual variability of the response to even the best of living high--training low strategies has been great, and the mechanisms behind this variability remain obscure. Future research efforts will need to focus on defining the optimal dosing strategy for these devices, and determining the underlying mechanisms of the individual variability so as to enable the individualized "prescription" of altitude exposure to optimize the performance of
International Nuclear Information System (INIS)
Rose, H.; Dubois, D.; Russell, D.; Hanssen, A.
1996-01-01
This is the final report of a three-year Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). This research concentrated on the time dependence of the heater, induced-turbulence, and electron-density profiles excited in the ionosphere by a powerful radio-frequency heater wave. The macroscopic density is driven by the ponderomotive pressure and the density self-consistently determines the heater propagation. For typical parameters of the current Arecibo heater, a dramatic quasi-periodic behavior was found. For about 50 ms after turn-on of the heater wave, the turbulence is concentrated at the first standing-wave maximum of the heater near reflection altitude. From 50--100 ms the standing-wave pattern drops by about 1--2 km in altitude and the quasi-periodicity reappears at the higher altitudes with a period of roughly 50 ms. This behavior is due to the half-wavelength density depletion grating that is set up by the ponderomotive pressure at the maxima of the heater standing-wave pattern. Once the grating is established the heater can no longer propagate to higher altitudes. The grating is then unsupported by the heater at these altitudes and decays, allowing the heater to propagate again and initiate another cycle. For stronger heater powers, corresponding to the Arecibo upgrade and the HAARP heater now under construction, the effects are much more dramatic
Reduction of Altitude Diffuser Jet Noise Using Water Injection
Allgood, Daniel C.; Saunders, Grady P.; Langford, Lester A.
2011-01-01
A feasibility study on the effects of injecting water into the exhaust plume of an altitude rocket diffuser for the purpose of reducing the far-field acoustic noise has been performed. Water injection design parameters such as axial placement, angle of injection, diameter of injectors, and mass flow rate of water have been systematically varied during the operation of a subscale altitude test facility. The changes in acoustic far-field noise were measured with an array of free-field microphones in order to quantify the effects of the water injection on overall sound pressure level spectra and directivity. The results showed significant reductions in noise levels were possible with optimum conditions corresponding to water injection at or just upstream of the exit plane of the diffuser. Increasing the angle and mass flow rate of water injection also showed improvements in noise reduction. However, a limit on the maximum water flow rate existed as too large of flow rate could result in un-starting the supersonic diffuser.
Isothermal pumping analysis for high-altitude tethered balloons.
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.
Dunker, Tim
2018-05-01
I investigate the nightly mean emission height and width of the OH* (3-1) layer by comparing nightly mean temperatures measured by the ground-based spectrometer GRIPS 9 and the Na lidar at ALOMAR. The data set contains 42 coincident measurements taken between November 2010 and February 2014, when GRIPS 9 was in operation at the ALOMAR observatory (69.3° N, 16.0° E) in northern Norway. To closely resemble the mean temperature measured by GRIPS 9, I weight each nightly mean temperature profile measured by the lidar using Gaussian distributions with 40 different centre altitudes and 40 different full widths at half maximum. In principle, one can thus determine the altitude and width of an airglow layer by finding the minimum temperature difference between the two instruments. On most nights, several combinations of centre altitude and width yield a temperature difference of ±2 K. The generally assumed altitude of 87 km and width of 8 km is never an unambiguous, good solution for any of the measurements. Even for a fixed width of ˜ 8.4 km, one can sometimes find several centre altitudes that yield equally good temperature agreement. Weighted temperatures measured by lidar are not suitable to unambiguously determine the emission height and width of an airglow layer. However, when actual altitude and width data are lacking, a comparison with lidars can provide an estimate of how representative a measured rotational temperature is of an assumed altitude and width. I found the rotational temperature to represent the temperature at the commonly assumed altitude of 87.4 km and width of 8.4 km to within ±16 K, on average. This is not a measurement uncertainty.
Effects of altitude and water on flowering and fruiting of jatropha curcas l
International Nuclear Information System (INIS)
Shiyu, M.A.; Zhou, L.; Guanglan, P.U.; Hou, L.
2015-01-01
Field survey was conducted at three different altitudes in the dry-hot valley of Chin-sha River,China. The variances of flowering and fruiting and the quantity of fruit at three different altitudes areas (Low 800m, Middle 1,200m and High 1,700m) were observed and recorded. Data of 100-seeds weight came from 9 experimental groups which classified by three fruiting periods (early, middle and late) at three different altitudes. To ensure single variable, water effect was studied in the cline banks where situated in the 1,200m and controlled by artificial irrigation. The results showed that flowering and fruiting time under different altitude had significant difference, the lower altitude, the earlier flowering. Fruit number in the middle elevation was remarkably higher than the other two altitude areas. Fruit quantity in early and middle fruiting period accounted for 85 percent at 1,200m, which was significantly higher than the late fruiting period. 100-seeds weight between low and middle elevation, early and middle fruiting period had no significant difference respectively, but they were, respectively, higher than the high altitude and late fruiting period. The maximum of the 100-seeds weight was 65.17g while the lightest was only 49.51g. Water promoted flowering earlier, fruiting delayed but open flower and whole fruiting stage extended. Average fruit numbers in the early and middle stages with regularly irrigation were 220.8 per tree and 195.6 per tree respectively, which were 2.26 times as the same period of plant without irrigation. Therefore, in hilly areas, J. curcas optimal elevation is 800 -1,200m and have high demand for water during flowering and fruiting period. (author)
Variation in aerodynamic coefficients with altitude
Directory of Open Access Journals (Sweden)
Faiza Shahid
Full Text Available Precise aerodynamics performance prediction plays key role for a flying vehicle to get its mission completed within desired accuracy. Aerodynamic coefficients for same Mach number can be different at different altitude due to difference in Reynolds number. Prediction of these aerodynamics coefficients can be made through experiments, analytical solution or Computational Fluid Dynamics (CFD. Advancements in computational power have generated the concept of using CFD as a virtual Wind Tunnel (WT, hence aerodynamic performance prediction in present study is based upon CFD (numerical test rig. Simulations at different altitudes for a range of Mach numbers with zero angle of attack are performed to predict axial force coefficient behavior with altitude (Reynolds number. Similar simulations for a fixed Mach number â3â and a range of angle of attacks are also carried out to envisage the variation in normal force and pitching moment coefficients with altitude (Reynolds number. Results clearly depict that the axial force coefficient is a function of altitude (Reynolds number and increase as altitude increases, especially for subsonic region. Variation in axial force coefficient with altitude (Reynolds number slightly increases for larger values of angle of attacks. Normal force and pitching moment coefficients do not depend on altitude (Reynolds number at smaller values of angle of attacks but show slight decrease as altitude increases. Present study suggests that variation of normal force and pitching moment coefficients with altitude can be neglected but the variation of axial force coefficient with altitude should be considered for vehicle fly in dense atmosphere. It is recommended to continue this study to more complex configurations for various Mach numbers with side slip and real gas effects. Keywords: Mach number, Reynolds number, Blunt body, Altitude effect, Angle of attacks
Bhardwaj, D R; Banday, Muneesa; Pala, Nazir A; Rajput, Bhalendra Singh
2016-11-01
In the present study, forests at three altitudes, viz., A 1 (600-900 m), A 2 (900-1200 m) and A 3 (1200-1500 m) above mean sea level having normalised differential vegetation index (NDVI) values of N 1 (0.0-0.1), N 2 (0.1-0.2), N 3 (0.2-0.3), N 4 (0.3-0.4) and N 5 (0.4-0.5) were selected for studying their relationship with the biomass and carbon pool in the state of Himachal Pradesh, India. The study reported maximum stem density of (928 trees ha -1 ) at the A 2 altitude and minimum in the A 3 and A 1 with 600 trees ha -1 each. The stem densities in relation to NDVIs were observed in the order N 5 > N 3 > N 4 > N 1 > N 2 and did not show any definite trend with increasing altitude. Highest stem volume (295.7 m 3 ha -1 ) was observed in N 1 NDVI and minimum (194.1 m 3 ha -1 ) in N 3 index. The trend observed for stem biomass at different altitudes was A 3 > A 1 > A 2 and for NDVIs, it was N 5 > N 1 > N 4 > N 2 > N 3 . Maximum aboveground biomass (265.83 t ha -1 ) was recorded in the 0.0-0.1 NDVI and minimum (169.05 t ha -1 ) in 0.2-0.3 NDVI index. Significantly, maximum total soil carbon density (90.82 t C ha -1 ) was observed in 0.4-0.5 NDVI followed by 0.3-0.4 NDVI (77.12 t C ha -1 ). The relationship between soil carbon and other studied parameters was derived through different functions simultaneously. Cubic function showed highest r 2 in most cases, followed by power, inverse and exponential function. The relationship with NDVI showed highest r 2 (0.62) through cubic functions. In relationship between ecosystem carbon with other parameters of different altitudinal gradient and NDVI, only one positively significant relation was formed with total density (0.579) through cubic function. The present study thus reveals that soil carbon density was directly related to altitude and NDVIs, but the vegetation carbon density did not bear any significant relation with altitude and NDVI.
Increased Hypoxic Dose After Training at Low Altitude with 9h Per Night at 3000m Normobaric Hypoxia.
Carr, Amelia J; Saunders, Philo U; Vallance, Brent S; Garvican-Lewis, Laura A; Gore, Christopher J
2015-12-01
This study examined effects of low altitude training and a live-high: train-low protocol (combining both natural and simulated modalities) on haemoglobin mass (Hbmass), maximum oxygen consumption (VO2max), time to exhaustion, and submaximal exercise measures. Eighteen elite-level race-walkers were assigned to one of two experimental groups; lowHH (low Hypobaric Hypoxia: continuous exposure to 1380 m for 21 consecutive days; n = 10) or a combined low altitude training and nightly Normobaric Hypoxia (lowHH+NHnight: living and training at 1380 m, plus 9 h.night(-1) at a simulated altitude of 3000 m using hypoxic tents; n = 8). A control group (CON; n = 10) lived and trained at 600 m. Measurement of Hbmass, time to exhaustion and VO2max was performed before and after the training intervention. Paired samples t-tests were used to assess absolute and percentage change pre and post-test differences within groups, and differences between groups were assessed using a one-way ANOVA with least significant difference post-hoc testing. Statistical significance was tested at p altitude (1380 m) combined with sleeping in altitude tents (3000 m) as one effective alternative to traditional altitude training methods, which can improve Hbmass. Key pointsIn some countries, it may not be possible to perform classical altitude training effectively, due to the low elevation at altitude training venues. An additional hypoxic stimulus can be provided by simulating higher altitudes overnight, using altitude tents.Three weeks of combined (living and training at 1380 m) and simulated altitude exposure (at 3000 m) can improve haemoglobin mass by over 3% in comparison to control values, and can also improve time to exhaustion by ~9% in comparison to baseline.We recommend that, in the context of an altitude training camp at low altitudes (~1400 m) the addition of a relatively short exposure to simulated altitudes of 3000 m can elicit physiological and performance benefits, without compromise to
Hughes, Benjamin H; Brinton, John T; Ingram, David G; Halbower, Ann C
2017-09-01
Sleep-disordered breathing (SDB) is prevalent among children and is associated with adverse health outcomes. Worldwide, approximately 250 million individuals reside at altitudes higher than 2000 meters above sea level (masl). The effect of chronic high-altitude exposure on children with SDB is unknown. This study aims to determine the impact of altitude on sleep study outcomes in children with SDB dwelling at high altitude. A single-center crossover study was performed to compare results of high-altitude home polysomnography (H-PSG) with lower altitude laboratory polysomnography (L-PSG) in school-age children dwelling at high altitude with symptoms consistent with SDB. The primary outcome was apnea-hypopnea index (AHI), with secondary outcomes including obstructive AHI; central AHI; and measures of oxygenation, sleep quality, and pulse rate. Twelve participants were enrolled, with 10 included in the final analysis. Median altitude was 1644 masl on L-PSG and 2531 masl on H-PSG. Median AHI was 2.40 on L-PSG and 10.95 on H-PSG. Both obstructive and central respiratory events accounted for the difference in AHI. Oxygenation and sleep fragmentation were worse and pulse rate higher on H-PSG compared to L-PSG. These findings reveal a clinically substantial impact of altitude on respiratory, sleep, and cardiovascular outcomes in children with SDB who dwell at high altitude. Within this population, L-PSG underestimates obstructive sleep apnea and central sleep apnea compared to H-PSG. Given the shortage of high-altitude pediatric sleep laboratories, these results suggest a role for home sleep apnea testing for children residing at high altitude. © Sleep Research Society 2017. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.
Variation in aerodynamic coefficients with altitude
Shahid, Faiza; Hussain, Mukkarum; Baig, Mirza Mehmood; Haq, Ihtram ul
Precise aerodynamics performance prediction plays key role for a flying vehicle to get its mission completed within desired accuracy. Aerodynamic coefficients for same Mach number can be different at different altitude due to difference in Reynolds number. Prediction of these aerodynamics coefficients can be made through experiments, analytical solution or Computational Fluid Dynamics (CFD). Advancements in computational power have generated the concept of using CFD as a virtual Wind Tunnel (WT), hence aerodynamic performance prediction in present study is based upon CFD (numerical test rig). Simulations at different altitudes for a range of Mach numbers with zero angle of attack are performed to predict axial force coefficient behavior with altitude (Reynolds number). Similar simulations for a fixed Mach number '3' and a range of angle of attacks are also carried out to envisage the variation in normal force and pitching moment coefficients with altitude (Reynolds number). Results clearly depict that the axial force coefficient is a function of altitude (Reynolds number) and increase as altitude increases, especially for subsonic region. Variation in axial force coefficient with altitude (Reynolds number) slightly increases for larger values of angle of attacks. Normal force and pitching moment coefficients do not depend on altitude (Reynolds number) at smaller values of angle of attacks but show slight decrease as altitude increases. Present study suggests that variation of normal force and pitching moment coefficients with altitude can be neglected but the variation of axial force coefficient with altitude should be considered for vehicle fly in dense atmosphere. It is recommended to continue this study to more complex configurations for various Mach numbers with side slip and real gas effects.
The topside ionosphere above Arecibo at equinox during sunspot maximum
International Nuclear Information System (INIS)
Bailey, G.J.
1980-01-01
The coupled time-dependent 0 + and H + continuity and momentum equations and 0 + , H + and electron heat balance equations are solved simultaneously within the L = 1.4 (Arecibo) magnetic flux tube between an altitude of 120 km and the equatorial plane. The results of the calculations are used in a study of the topside ionosphere above Arecibo at equinox during sunspot maximum. Magnetically quiet conditions are assumed. The results of the calculations show that the L = 1.4 magnetic flux tube becomes saturated from an arbitrary state within 2-3 days. During the day the ion content of the magnetic flux tube consists mainly of 0 + whereas 0 + and H + are both important during the night. There is an altitude region in the topside ionosphere during the day where ion-counterstreaming occurs with H + flowing downward and 0 + flowing upward. The conditions causing this ion-counterstreaming are discussed. There is a net chemical gain of H + at the higher altitudes. This H + diffuses both upwards and downwards whilst 0 + diffuses upwards from its solar e.u.v. production source which is most important at the lower altitudes. During the night the calculated 0 + and H + temperatures are very nearly equal whereas during the day there are occasions when the H + temperature exceeds the 0 - temperature by about 300 K. (author)
Directory of Open Access Journals (Sweden)
Murat Yalcin
2011-04-01
Full Text Available Nowadays, situations associated with high altitude such as mountaineering, aviation increasingly draw the attention of people. Gas pressure decreases and hypoxia is encountered when climbing higher. Physiological and pathological responses of human body to different heights are different. Therefore, physiological and pathological changes that may occur together with height and to know the clinical outcomes of these are important . Acute mountain sickness caused by high altitude and high altitude cerebral edema are preventable diseases with appropriate precautions. Atmospheric oxygen decreasing with height, initiates many adaptive mechanisms. These adaptation mechanisms and acclimatization vary widely among individuals because of reasons such as environmental factors, exercise and cold. High altitude causes different changes in the cardiovascular system with various mechanisms. Although normal individuals easily adapt to these changes, this situation can lead to undesirable results in people with heart disease. For this reason, it should be known the effective evaluation of the people with known heart disease before traveling to high altitude and the complications due to the changes with height and the recommendations can be made to these patients. [TAF Prev Med Bull 2011; 10(2.000: 211-222
Directory of Open Access Journals (Sweden)
Andrew M. Luks
2017-02-01
Full Text Available At any point 1–5 days following ascent to altitudes ≥2500 m, individuals are at risk of developing one of three forms of acute altitude illness: acute mountain sickness, a syndrome of nonspecific symptoms including headache, lassitude, dizziness and nausea; high-altitude cerebral oedema, a potentially fatal illness characterised by ataxia, decreased consciousness and characteristic changes on magnetic resonance imaging; and high-altitude pulmonary oedema, a noncardiogenic form of pulmonary oedema resulting from excessive hypoxic pulmonary vasoconstriction which can be fatal if not recognised and treated promptly. This review provides detailed information about each of these important clinical entities. After reviewing the clinical features, epidemiology and current understanding of the pathophysiology of each disorder, we describe the current pharmacological and nonpharmacological approaches to the prevention and treatment of these diseases.
Klarod, Kultida; Philippe, Marc; Gatterer, Hannes; Burtscher, Martin
2017-01-01
This pilot study aimed (a) to evaluate the effects of eccentric exercise training at low and moderate altitudes on physical fitness in pre-diabetic men and (b) to establish whether or not oxidative stress levels and antioxidant status were associated with performance improvements. In this crossover trial, five pre-diabetic men conducted nine downhill walking sessions (3 days/week, 3 consecutive weeks) at low altitude (from 1360 to 850 m) and one year later at moderate altitude (from 2447 to 2000 m). Exercise testing and the determination of parameters of oxidative stress and antioxidant capacity were performed pre- and post-training. The biological antioxidant activity of plasma (BAP) increased after eccentric training at moderate altitude ( p training at moderate-altitude training ( p = 0.009). Maximum power output improved after training at low altitude and the changes were significantly related to baseline BAP/dROMs ratio ( r = 0.90). No decrease was seen for fasting plasma glucose. Eccentric exercise training in pre-diabetic men improved performance only when performed at low altitude and this improvement was positively related to the baseline BAP/dROMs ratio. In contrast, 3 weeks of eccentric exercise training increased BAP levels and the BAP/dROMs ratio only at moderate altitude without improving the performance. Thus, one might speculate that the BAP/dROMs ratio has to increase before performance improvements occur at moderate altitude.
High-altitude pulmonary hypertension
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X-Q. Xu
2009-03-01
Full Text Available High-altitude pulmonary hypertension (HAPH is a specific disease affecting populations that live at high elevations. The prevalence of HAPH among those residing at high altitudes needs to be further defined. Whereas reduction in nitric oxide production may be one mechanism for the development of HAPH, the roles of endothelin-1 and prostaglandin I2 pathways in the pathogenesis of HAPH deserve further study. Although some studies have suggested that genetic factors contribute to the pathogenesis of HAPH, data published to date are insufficient for the identification of a significant number of gene polymorphims in HAPH. The clinical presentation of HAPH is nonspecific. Exertional dyspnoea is the most common symptom and signs related to right heart failure are common in late stages of HAPH. Echocardiography is the most useful screening tool and right heart catheterisation is the gold standard for the diagnosis of HAPH. The ideal management for HAPH is migration to lower altitudes. Phosphodiesterase 5 is an attractive drug target for the treatment of HAPH. In addition, acetazolamide is a promising therapeutic agent for high-altitude pulmonary hypertension. To date, no evidence has confirmed whether endothelin-receptor antagonists have efficacy in the treatment of high-altitude pulmonary hypertension.
Fleming, William A.
1948-01-01
An investigation was conducted in the Cleveland altitude wind tunnel to determine the operational characteristics of an axial flow-type turbojet engine with a 4000-pound-thrust rating over a range of pressure altitudes from 5,000 to 50,OOO feet, ram pressure ratios from 1.00 to 1.86, and temperatures from 60 deg to -50 deg F. The low-flow (standard) compressor with which the engine was originally equipped was replaced by a high-flow compressor for part of the investigation. The effects of altitude and airspeed on such operating characteristics as operating range, stability of combustion, acceleration, starting, operation of fuel-control systems, and bearing cooling were investigated. With the low-flow compressor, the engine could be operated at full speed without serious burner unbalance at altitudes up to 50,000 feet. Increasing the altitude and airspeed greatly reduced the operable speed range of the engine by raising the minimum operating speed of the engine. In several runs with the high-flow compressor the maximum engine speed was limited to less than 7600 rpm by combustion blow-out, high tail-pipe temperatures, and compressor stall. Acceleration of the engine was relatively slow and the time required for acceleration increased with altitude. At maximum engine speed a sudden reduction in jet-nozzle area resulted in an immediate increase in thrust. The engine started normally and easily below 20,000 feet with each configuration. The use of a high-voltage ignition system made possible starts at a pressure altitude of 40,000 feet; but on these starts the tail-pipe temperatures were very high, a great deal of fuel burned in and behind the tail-pipe, and acceleration was very slow. Operation of the engine was similar with both fuel regulators except that the modified fuel regulator restricted the fuel flow in such a manner that the acceleration above 6000 rpm was very slow. The bearings did not cool properly at high altitudes and high engine speeds with a low
Attempt to measure the cosmic background radiation at high altitude
International Nuclear Information System (INIS)
Labeyrie, Jacques; Le Boiteux, Henri
1959-01-01
Results are given of the measurement by G.M. tubes of hard component of cosmic background between o and 60 km of altitude, at 43 deg. N latitude, on january 27, 1959 (17 h. GMT). The counting rate starts at 0.3 pulses per second (sea level) reaches a maximum value of 15.6 (18 km) and remains constant at 5.7 above 40 km. Reprint of a paper published in Le Journal de Physique et le Radium, t. 20, p. 573, may 1959
Altitude Stress During Participation of Medical Congress
Kim, Soon Bae; Kim, Jong Sung; Kim, Sang Jun; Cho, Su Hee
2016-01-01
Medical congresses often held in highlands. We reviewed several medical issues associated with altitude stress especially while physicians have participated medical congress held in high altitude. Altitude stress, also known as an acute mountain sickness (AMS), is caused by acute exposure to low oxygen level at high altitude which is defined as elevations at or above 1,200 m and AMS commonly occurs above 2,500 m. Altitude stress with various symptoms including insomnia can also be experienced in airplane. AMS and drunken state share many common features in symptoms, neurologic manifestations and even show multiple microbleeds in corpus callosum and white matter on MRI. Children are more susceptible to altitude stress than adults. Gradual ascent is the best method for the prevention of altitude stress. Adequate nutrition (mainly carbohydrates) and hydration are recommended. Consumption of alcohol can exacerbate the altitude-induced impairments in judgment and the visual senses and promote psychomotor dysfunction. For prevention or treatment of altitude stress, acetazolamide, phosphodiesterase inhibitors, dexamethasone and erythropoietin are helpful. Altitude stress can be experienced relatively often during participation of medical congress. It is necessary to remind the harmful effect of AMS because it can cause serious permanent organ damage even though the symptoms are negligible in most cases. PMID:27621942
Performance of portable ventilators at altitude.
Blakeman, Thomas; Britton, Tyler; Rodriquez, Dario; Branson, Richard
2014-09-01
Aeromedical transport of critically ill patients requires continued, accurate performance of equipment at altitude. Changes in barometric pressure can affect the performance of mechanical ventilators calibrated for operation at sea level. Deploying ventilators that can maintain a consistent tidal volume (VT) delivery at various altitudes is imperative for lung protection when transporting wounded war fighters to each echelon of care. Three ventilators (Impact 731, Hamilton T1, and CareFusion Revel) were tested at pediatric (50 and 100 mL) and adult (250-750 mL) tidal VTs at 0 and 20 cm H₂O positive end expiratory pressure and at inspired oxygen of 0.21 and 1.0. Airway pressure, volume, and flow were measured at sea level as well as at 8,000, 16,000, and 22,000 ft (corresponding to barometric pressures of 760, 564, 412, and 321 mm Hg) using a calibrated pneumotachograph connected to a training test lung in an altitude chamber. Set VT and delivered VT as well as changes in VT at each altitude were compared by t test. The T1 delivered VT within 10% of set VT at 8,000 ft. The mean VT was less than set VT at sea level as a result of circuit compressible volume with the Revel and the 731. Changes in VT varied widely among the devices at sea level and at altitude. Increasing altitudes resulted in larger VT than set for the Revel and the T1. The 731 compensated for changes in altitude delivered VT within 10% at the adult settings at all altitudes. Altitude compensation is an active software algorithm. Only the 731 actively accounts for changes in barometric pressure to maintain the set VT at all tested altitudes.
VisibleWind: wind profile measurements at low altitude
Wilkerson, Tom; Bradford, Bill; Marchant, Alan; Apedaile, Tom; Wright, Cordell
2009-09-01
VisibleWindTM is developing an inexpensive rapid response system, for accurately characterizing wind shear and small scale wind phenomena in the boundary layer and for prospecting suitable locations for wind power turbines. The ValidWind system can also collect reliable "ground truth" for other remote wind sensors. The system employs small (0.25 m dia.) lightweight balloons and a tracker consisting of an Impulse 200 XL laser rangefinder coupled to a PC for automated data recording. Experiments on balloon trajectories demonstrate that the laser detection of range (+/- 0.5 m), together with measured azimuth and altitude, is an inexpensive, convenient, and capable alternative to other wind tracking methods. The maximum detection range has been increased to 2200 meters using micro-corner-cube retroreflector tape on balloons. Low power LEDs enable nighttime tracking. To avoid large balloon gyrations about the mean trajectory, we use balloons having low ascent rates and subcritical Reynolds numbers. Trajectory points are typically recorded every 4 - 7 seconds. Atmospheric features observed under conditions of inversions or "light and variable winds" include abrupt onsets of shear at altitudes of 100-250 m, velocity changes of order 1-3 m/s within layers of 10-20 m thickness, and veering of the wind direction by 180 degrees or more as altitude increases from 300 to 500 m. We have previously reported comparisons of balloon-based wind profiles with the output of a co-located sodar. Even with the Impulse rangefinder, our system still requires a "man in the loop" to track the balloon. A future system enhancement will automate balloon tracking, so that laser returns are obtained automatically at 1 Hz. While balloon measurements of large-scale, high altitude wind profiles are well known, this novel measurement system provides high-resolution, real-time characterization of the fluctuating local wind fields at the bottom of the boundary layer where wind power turbines and other
Growth and maximum size of tiger sharks (Galeocerdo cuvier) in Hawaii.
Meyer, Carl G; O'Malley, Joseph M; Papastamatiou, Yannis P; Dale, Jonathan J; Hutchinson, Melanie R; Anderson, James M; Royer, Mark A; Holland, Kim N
2014-01-01
Tiger sharks (Galecerdo cuvier) are apex predators characterized by their broad diet, large size and rapid growth. Tiger shark maximum size is typically between 380 & 450 cm Total Length (TL), with a few individuals reaching 550 cm TL, but the maximum size of tiger sharks in Hawaii waters remains uncertain. A previous study suggested tiger sharks grow rather slowly in Hawaii compared to other regions, but this may have been an artifact of the method used to estimate growth (unvalidated vertebral ring counts) compounded by small sample size and narrow size range. Since 1993, the University of Hawaii has conducted a research program aimed at elucidating tiger shark biology, and to date 420 tiger sharks have been tagged and 50 recaptured. All recaptures were from Hawaii except a single shark recaptured off Isla Jacques Cousteau (24°13'17″N 109°52'14″W), in the southern Gulf of California (minimum distance between tag and recapture sites = approximately 5,000 km), after 366 days at liberty (DAL). We used these empirical mark-recapture data to estimate growth rates and maximum size for tiger sharks in Hawaii. We found that tiger sharks in Hawaii grow twice as fast as previously thought, on average reaching 340 cm TL by age 5, and attaining a maximum size of 403 cm TL. Our model indicates the fastest growing individuals attain 400 cm TL by age 5, and the largest reach a maximum size of 444 cm TL. The largest shark captured during our study was 464 cm TL but individuals >450 cm TL were extremely rare (0.005% of sharks captured). We conclude that tiger shark growth rates and maximum sizes in Hawaii are generally consistent with those in other regions, and hypothesize that a broad diet may help them to achieve this rapid growth by maximizing prey consumption rates.
The paradox of extreme high-altitude migration in bar-headed geese Anser indicus
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
Directory of Open Access Journals (Sweden)
Qi-quan ZHOU
2012-02-01
Full Text Available Objective To investigate the diagnostic method of high-altitude de-adaptation and constitute the diagnostic criteria of high-altitude de-adaptation for people returning to the plains from high-altitude. Methods Epidemiological survey and clinical multicenter randomized controlled studies were used to determine/perform blood picture, routine urine analysis, routine stool examination, myocardial enzymes, liver and kidney functions, nerve function, sex hormone, microalbuminuria, ECG, echocardiography, pulmonary function tests, and so on, in 3011 subjects after they returned to the plains from high-altitude. The diagnostic criteria of high-altitude de-adaptation were formulated by a comparative analysis of the obtained data with those of healthy subjects living in the same area, altitude, and age. The regularity and characteristics of high-altitude de-adaptation syndrome were found and diagnostic criteria for high-altitude de-adaptation was established based on the results. Results The investigative results showed that the incidence of high-altitude de-adaptation syndrome was found in 84.36% of population returning to the plains from high-altitude. About 60% of them were considered to have mild reactions, 30% medium, and only 10% were severe. The lower the altitude they returned to, the longer the duration of stay in highland, and the heavier the labor they engaged in high altitude, the higher the incidence rate of high-altitude de-adaptation syndrome was. Patients with high-altitude de-adaptation syndrome exhibited hematological abnormality and abnormal ventricular function, especially the right ventricular diastolic function after returning for 1 year to 5 years. Long-term hypoxia exposure often caused obvious change in cardiac morphology with left and right ventricular hypertrophy, particularly the right ventricle. In addition, low blood pressure and low pulse pressure were found at times. Microalbuminuria was found in some high-altitude de
Federal Laboratory Consortium — The Altitude Lab evaluates the performance of complete oxygen systems operated in individually controlled hypobaric chambers, which duplicate pressures that would be...
ABOUT TRANSITION ALTITUDE IN RUSSIAN FEDERATION
Directory of Open Access Journals (Sweden)
2016-01-01
Full Text Available This article is about establishing a common transition altitude over all territory of Russian Federation. The main objective is to prove the necessity of a common transition altitude in Russian airspace and to define, which variant of tran- sition altitude (low, medium, high is the most suitable to be implemented in Russia. ICAO and IFALPA points of view, data and experience from different states and regions all over the world were examined in order to show all the advantages and disadvantages of different approaches towards common transition altitude. The research showed that the most appro- priate common transition altitude in Russia will be 10000 feet (3050 meters, it will cover almost all the international aero- dromes and regions in the country. Only several exceptions are needed in mountainous areas. This article can be used to further study of the possibility of implementation of common transition altitude, because it can’t take into consideration all the local features of all the FIRs (Flight Information Regions in Russia. The conclusion is establishing a common transi- tion altitude over such a big part of the world as Russian Federation will lead to improvement of the flight safety, harmoni- zation with ICAO and IFALPA policies and flexibility in airspace design.
Directory of Open Access Journals (Sweden)
M.A. Kenawy
2015-08-01
Full Text Available Asir Region in the southwest of Saudi Arabia has been a subject for expansion of agricultural projects, urbanization, which presumably have impact on distribution of phlebotomine sandflies. Few reports are available on sandflies in this region which is an important focus of cutaneous leishmaniasis. Therefore, this study aimed at updating the species composition, distribution and periodical fluctuation of sandflies in this region. Specimens were monthly collected by the Center for Disease Control light traps for one year in four localities representing different altitudes. In five other, collections were twice during the year period. Ten species (six Phlebotomus and four Sergentomyia were identified, of which P. arabicus (32% was the most common followed by P. bergeroti (29% and P. sergenti (15%. Of the reported species, S. palestinensis is considered a new record from Asir. Sandflies were more common and maximum biodiversity was observed in lowlands and not in high altitudes. At different altitudes, the two commonest species were more active during spring. Sandfly density (sandfly/trap was directly related to temperature and inversely related to altitude, relative humidity (RH and wind velocity (P<0.05. To sum up, the distribution and abundance of sandflies in Asir are influenced by a combination of different factors: temperature, RH, wind velocity and altitude.
Directory of Open Access Journals (Sweden)
Miroslav Semerád
2017-11-01
Full Text Available The purpose of our pilot study was to find out if total body water (TBW changes could objectively modify the course of adaptation during training for elite runners at different altitudes. The aim of this pilot study is to summarize the indication of the progress of acclimatization at high altitudes (1000–2700 meters above sea level during alpine conditioning. In three training camps at various altitudes the TBW of elite runners (F = 3, M = 1; n = 4; age 23 } 0.9 was monitored, in order to check the progress of acclimatization. We used BIA measurement methods (Bodystat 1500 at different high altitude running camps at the Czech Republic, Morocco and Ethiopia. Changes in TBW were used to check the progress of acclimatization. We discovered that the retention peaks of TBW corresponded with critical days (p ≤ 0.04; Cohen’s d. The highest measured increases of TBW at an altitude of 1000 m were for runner 1, 1.7 litres and for runner 2, 2.1 litres with retention peaks for both occurring on the 5th day. At an altitude of 1770 m runner 1 reached an increase of TBW of 6.3 litres, with a retention peak on the 11th day, and runner 3 had an increase of 5.1 litres with a peak on the 8th day. In the acclimatization phase we found two critical periods, from the 4th–6th day, and after the 10th–12th day. For runner 4 in altitude 2700m who completed the camp at a higher altitude, the situation is more complicated because there were fluctuations of the content of TBW in the range of 1.25 litres, with the highest depression on the 5th and then again an unsettled rise and reaching a maximum on the 12th, when she nearly returned to the initial value. Detected retention peaks reflected different levels of altitude (5th–12th days.We can conclude that the measuring of changes in TBW during camps at higher altitudes may be one of the biomarkers during acclimatization to altitude.
Introduction to altitude/hypoxic training symposium.
Wilber, Randall L
2007-09-01
Altitude/hypoxic training has traditionally been an intriguing and controversial area of research and sport performance. This controversial aspect was evident recently in the form of scholarly debates in highly regarded professional journals, as well as the World Anti-Doping Agency's (WADA) consideration of placing "artificially-induced hypoxic conditions" on the 2007 Prohibited List of Substances/Methods. In light of the ongoing controversy surrounding altitude/hypoxic training, this symposium was organized with the following objectives in mind: 1) to examine the primary physiological responses and underlying mechanisms associated with altitude/hypoxic training, including the influence of genetic predisposition; 2) to present evidence supporting the effect of altitude/hypoxic acclimatization on both hematological and nonhematological markers, including erythrocyte volume, skeletal muscle-buffering capacity, hypoxic ventilatory response, and physiological efficiency/economy; 3) to evaluate the efficacy of several contemporary simulated altitude modalities and training strategies, including hypoxic tents, nitrogen apartments, and intermittent hypoxic exposure (IHE) or training, and to address the legal and ethical issues associated with the use of simulated altitude; and 4) to describe different altitude/hypoxic training strategies used by elite-level athletes, including Olympians and military special forces. In addressing these objectives, papers will be presented on the topics of: 1) effect of hypoxic "dose" on physiological responses and sea-level performance (Drs. Benjamin Levine and James Stray-Gundersen), 2) nonhematological mechanisms of improved performance after hypoxic exposure (Dr. Christopher Gore), 3) application of altitude/hypoxic training by elite athletes (Dr. Randall Wilber), and 4) military applications of hypoxic training (Dr. Stephen Muza).
Altitude exposures during commercial flight: a reappraisal.
Hampson, Neil B; Kregenow, David A; Mahoney, Anne M; Kirtland, Steven H; Horan, Kathleen L; Holm, James R; Gerbino, Anthony J
2013-01-01
Hypobaric hypoxia during commercial air travel has the potential to cause or worsen hypoxemia in individuals with pre-existing cardiopulmonary compromise. Knowledge of cabin altitude pressures aboard contemporary flights is essential to counseling patients accurately about flying safety. The objective of the study was to measure peak cabin altitudes during U.S. domestic commercial flights on a variety of aircraft. A handheld mountaineering altimeter was carried by the investigators in the plane cabin during commercial air travel and peak cabin altitude measured. The values were then compared between aircraft models, aircraft classes, and distances flown. The average peak cabin altitude on 207 flights aboard 17 different aircraft was 6341 +/- 1813 ft (1933 m +/- 553 m), significantly higher than when measured in a similar fashion in 1988. Peak cabin altitude was significantly higher for flights longer than 750 mi (7085 +/- 801 ft) compared to shorter flights (5160 +/- 2290 ft/1573 +/- 698 m). Cabin altitude increased linearly with flight distance for flights up to 750 mi in length, but was independent of flight distance for flights exceeding 750 mi. Peak cabin altitude was less than 5000 ft (1524 m) in 70% of flights shorter than 500 mi. Peak cabin altitudes greater than 8000 ft (2438 m) were measured on approximately 10% of the total flights. Peak cabin altitude on commercial aircraft flights has risen over time. Cabin altitude is lower with flights of shorter distance. Physicians should take these factors into account when determining an individual's need for supplemental oxygen during commercial air travel.
Altitude training improves glycemic control.
Chen, Shu-Man; Lin, Hsueh-Yi; Kuo, Chia-Hua
2013-08-31
Under altitude hypoxia condition, energy reliance on anaerobic glycolysis increases to compensate the shortfall caused by reduced fatty acid oxidation. Short-term moderate altitude exposure plus endurance physical activity has been found to improve glucose tolerance (not fasting glucose) in humans, which is associated with the improvement in the whole-body insulin sensitivity. However, most of people cannot accommodate high altitude exposure above 4500 M due to acute mountain sickness and insulin resistance. There is a wide variation among individuals in response to the altitude challenge. In particular, the improvement in glucose tolerance and insulin sensitivity by prolonged altitude hiking activity was not apparent in those individuals with low baseline dehydroepiandrosterone sulfate (DHEA-S) concentration. In rats, exercise training recovery under prolonged hypoxia exposure (14-15% oxygen, 8 h per day for 6 weeks) can also improve insulin sensitivity, secondary to an effective suppression of adiposity. After prolonged hypoxia training, obese abnormality in upregulated baseline levels of AMP-activated protein kinase (AMPK) and AS160 phosphorylation in skeletal muscle can be reversed. In humans, moderate hypoxia increases postprandial blood distribution towards skeletal muscle during a training recovery. This physiological response plays a role in the redistribution of fuel storage among important energy storage sites and may explain its potent effect on the favorable change in body composition. Altitude training can exert strong impact on our metabolic system, and has the potential to be designed as a non-pharmacological or recreational intervention regimen for correcting metabolic syndromes.
DEFF Research Database (Denmark)
Lundby, Carsten; Calbet, Jose A L; van Hall, Gerrit
2004-01-01
We aimed to test effects of altitude acclimatization on pulmonary gas exchange at maximal exercise. Six lowlanders were studied at sea level, in acute hypoxia (AH), and after 2 and 8 wk of acclimatization to 4,100 m (2W and 8W) and compared with Aymara high-altitude natives residing...... in AH but increased significantly with acclimatization (51 +/- 1.1, 58 +/- 1.7, and 62 +/- 1.6 mmHg in AH, 2W, and 8W, respectively). PaO2 in lowlanders reached levels that were not different from those in high-altitude natives (66 +/- 1.2 mmHg). Arterial O2 saturation (SaO2) decreased during maximum......, but even acclimatization for 8 wk is insufficient to achieve levels reached by high-altitude natives....
Eldridge, Marlowe W; Braun, Ruedi K; Yoneda, Ken Y; Walby, William F
2006-03-01
Strenuous exercise may be a significant contributing factor for development of high-altitude pulmonary edema, particularly at low or moderate altitudes. Thus we investigated the effects of heavy cycle ergometer exercise (90% maximal effort) under hypoxic conditions in which the combined effects of a marked increase in pulmonary blood flow and nonuniform hypoxic pulmonary vasoconstriction could add significantly to augment the mechanical stress on the pulmonary microcirculation. We postulated that intense exercise at altitude would result in an augmented permeability edema. We recruited eight endurance athletes and examined their bronchoalveolar lavage fluid (BALF) for red blood cells (RBCs), protein, inflammatory cells, and soluble mediators at 2 and 26 h after intense exercise under normoxic and hypoxic conditions. After heavy exercise, under all conditions, the athletes developed a permeability edema with high BALF RBC and protein concentrations in the absence of inflammation. We found that exercise at altitude (3,810 m) caused significantly greater leakage of RBCs [9.2 (SD 3.1)x10(4) cells/ml] into the alveolar space than that seen with normoxic exercise [5.4 (SD 1.2)x10(4) cells/ml]. At altitude, the 26-h postexercise BALF revealed significantly higher RBC and protein concentrations, suggesting an ongoing capillary leak. Interestingly, the BALF profiles following exercise at altitude are similar to that of early high-altitude pulmonary edema. These findings suggest that pulmonary capillary disruption occurs with intense exercise in healthy humans and that hypoxia augments the mechanical stresses on the pulmonary microcirculation.
High Altitude Launch for a Practical SSTO
Landis, Geoffrey A.; Denis, Vincent
2003-01-01
Existing engineering materials allow the constuction of towers to heights of many kilometers. Orbital launch from a high altitude has significant advantages over sea-level launch due to the reduced atmospheric pressure, resulting in lower atmospheric drag on the vehicle and allowing higher rocket engine performance. High-altitude launch sites are particularly advantageous for single-stage to orbit (SSTO) vehicles, where the payload is typically 2% of the initial launch mass. An earlier paper enumerated some of the advantages of high altitude launch of SSTO vehicles. In this paper, we calculate launch trajectories for a candidate SSTO vehicle, and calculate the advantage of launch at launch altitudes 5 to 25 kilometer altitudes above sea level. The performance increase can be directly translated into increased payload capability to orbit, ranging from 5 to 20% increase in the mass to orbit. For a candidate vehicle with an initial payload fraction of 2% of gross lift-off weight, this corresponds to 31% increase in payload (for 5-km launch altitude) to 122% additional payload (for 25-km launch altitude).
Observation of low energy particle precipitation at low altitude in the equatorial zone
International Nuclear Information System (INIS)
Miah, M.A.
1989-01-01
Precipitation of protons (∼ 1 MeV) in the equatorial zone was investigated by the Phoenix-1 experiment on board the S81-1 mission from May-November, 1982. The protons show a precipitation peak along the line of minimum magnetic field strength with a full width at half maximum (FWHM) of 13 0 . The index of equatorial pitch angle distribution is q ∼ 19. The peak proton flux shows a fifth-power altitude dependence, and the proton flux shows approximately a factor of 3 times increase in 1982 compared to that in 1969 due, possibly, to the stronger (∼ 1.2 times) solar maximum conditions of 10.7 cm radiation in 1982. (author)
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.
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Paul J. Anderson
2011-01-01
Full Text Available Introduction Each year, the US Antarctic Program rapidly transports scientists and support personnel from sea level (SL to the South Pole (SP, 2835 m providing a unique natural laboratory to quantify the incidence of acute mountain sickness (AMS, patterns of altitude related symptoms and the field effectiveness of acetazolamide in a highly controlled setting. We hypothesized that the combination of rapid ascent (3 hr, accentuated hypobarism (relative to altitude, cold, and immediate exertion would increase altitude illness risk. Methods Medically screened adults (N = 246, age = 37 ± 11 yr, 30% female, BMI = 26 ± 4 kg/m 2 were recruited. All underwent SL and SP physiological evaluation, completed Lake Louise symptom questionnaires (LLSQ, to define AMS, and answered additional symptom related questions (eg, exertional dyspnea, mental status, cough, edema and general health, during the 1st week at altitude. Acetazolamide, while not mandatory, was used by 40% of participants. Results At SP, the barometric pressure resulted in physiological altitudes that approached 3400 m, while T ° C averaged -42, humidity 0.03%. Arterial oxygen saturation averaged 89% ± 3%. Overall, 52% developed LLSQ defined AMS. The most common symptoms reported were exertional dyspnea-(87%, sleeping difficulty-(74%, headache-(66%, fatigue-(65%, and dizziness/lightheadedness-(46%. Symptom severity peaked on days 1-2, yet in >20% exertional dyspnea, fatigue and sleep problems persisted through day 7. AMS incidence was similar between those using acetazolamide and those abstaining (51 vs. 52%, P = 0.87. Those who used acetazolamide tended to be older, have less altitude experience, worse symptoms on previous exposures, and less SP experience. Conclusion The incidence of AMS at SP tended to be higher than previously reports in other geographic locations at similar altitudes. Thus, the SP constitutes a more intense altitude exposure than might be expected considering physical
Early history of high-altitude physiology.
West, John B
2016-02-01
High-altitude physiology can be said to have begun in 1644 when Torricelli described the first mercury barometer and wrote the immortal words "We live submerged at the bottom of an ocean of the element air." Interestingly, the notion of atmospheric pressure had eluded his teacher, the great Galileo. Blaise Pascal was responsible for describing the fall in pressure with increasing altitude, and Otto von Guericke gave a dramatic demonstration of the enormous force that could be developed by atmospheric pressure. Robert Boyle learned of Guericke's experiment and, with Robert Hooke, constructed the first air pump that allowed small animals to be exposed to a low pressure. Hooke also constructed a small low-pressure chamber and exposed himself to a simulated altitude of about 2400 meters. With the advent of ballooning, humans were rapidly exposed to very low pressures, sometimes with tragic results. For example, the French balloon, Zénith, rose to over 8000 m, and two of the three aeronauts succumbed to the hypoxia. Paul Bert was the first person to clearly state that the deleterious effects of high altitude were caused by the low partial pressure of oxygen (PO2), and later research was accelerated by high-altitude stations and expeditions to high altitude. © 2015 New York Academy of Sciences.
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
Langowski, M.; vonSavigny, C.; Burrows, J. P.; Feng, W.; Plane, J. M. C.; Marsh, D. R.; Janches, Diego; Sinnhuber, M.; Aikin, A. C.
2014-01-01
Mg and Mg+ concentration fields in the upper mesosphere/lower thermosphere (UMLT) region are retrieved from SCIAMACHY/Envisat limb measurements of Mg and Mg+ dayglow emissions using a 2-D tomographic retrieval approach. The time series of monthly means of Mg and Mg+ for number density as well as vertical column density in different latitudinal regions are shown. Data from the limb mesosphere-thermosphere mode of SCIAMACHY/Envisat are used, which covers the 50 km to 150 km altitude region with a vertical sampling of 3.3 km and a highest latitude of 82 deg. The high latitudes are not covered in the winter months, because there is no dayglow emission during polar night. The measurements were performed every 14 days from mid-2008 until April 2012. Mg profiles show a peak at around 90 km altitude with a density between 750 cm(exp-3) and 2000 cm(exp-3). Mg does not show strong seasonal variation at mid-latitudes. The Mg+ peak occurs 5-15 km above the neutral Mg peak at 95-105 km. Furthermore, the ions show a significant seasonal cycle with a summer maximum in both hemispheres at mid- and high-latitudes. The strongest seasonal variations of the ions are observed at mid-latitudes between 20-40 deg and densities at the peak altitude range from 500 cm(exp-3) to 6000 cm(exp-3). The peak altitude of the ions shows a latitudinal dependence with a maximum at mid-latitudes that is up to 10 km higher than the peak altitude at the equator. The SCIAMACHY measurements are compared to other measurements and WACCM model results. In contrast to the SCIAMACHY results, the WACCM results show a strong seasonal variability for Mg with a winter maximum, which is not observable by SCIAMACHY, and globally higher peak densities. Although the peak densities do not agree the vertical column densities agree, since SCIAMACHY results show a wider vertical profile. The agreement of SCIAMACHY and WACCM results is much better for Mg+, showing the same seasonality and similar peak densities. However
Propagation and Breaking at High Altitudes of Gravity Waves Excited by Tropospheric Forcing
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.
Optimum detection for extracting maximum information from symmetric qubit sets
International Nuclear Information System (INIS)
Mizuno, Jun; Fujiwara, Mikio; Sasaki, Masahide; Akiba, Makoto; Kawanishi, Tetsuya; Barnett, Stephen M.
2002-01-01
We demonstrate a class of optimum detection strategies for extracting the maximum information from sets of equiprobable real symmetric qubit states of a single photon. These optimum strategies have been predicted by Sasaki et al. [Phys. Rev. A 59, 3325 (1999)]. The peculiar aspect is that the detections with at least three outputs suffice for optimum extraction of information regardless of the number of signal elements. The cases of ternary (or trine), quinary, and septenary polarization signals are studied where a standard von Neumann detection (a projection onto a binary orthogonal basis) fails to access the maximum information. Our experiments demonstrate that it is possible with present technologies to attain about 96% of the theoretical limit
Maximum attainable power density and wall load in tokamaks underlying reactor relevant constraints
International Nuclear Information System (INIS)
Borrass, K.; Buende, R.
1979-09-01
The characteristic data of tokamaks optimized with respect to their power density or wall load are determined. Reactor relevant constraints are imposed, such as a fixed plant net power output, a fixed blanket thickness and the dependence of the maximum toroidal field on the geometry and conductor material. The impact of finite burn times is considered. Various scaling laws of the toroidal beta with the aspect ratio are discussed. (orig.) 891 GG/orig. 892 RDG [de
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Toshio Matsuoka
2004-09-01
Full Text Available Training at moderate altitude (~1800m is often used by athletes to stimulate muscle hypoxia. However, limited date is available on peripheral muscle oxidative metabolism at this altitude (1800AL. The purpose of this study was to determine whether acute exposure to 1800AL alters muscle oxygenation in the vastus lateralis muscle during resistance exercise. Twenty young active male subjects (aged 16 - 21 yr performed up to 50 repetitions of the parallel squat at 1800AL and near sea level (SL. They performed the exercise protocol within 3 h after arrival at 1800 AL. During the exercise, the changes in oxygenated hemoglobin (OxyHb in the vastus lateralis muscle, arterial oxygen saturation (SpO2, and heart rate were measured using near infrared continuous wave spectroscopy (NIRcws and pulse oximetry, respectively. Changes in OxyHb were expressed by Deff defined as the relative index of the maximum change ratio (% from the resting level. OxyHb in the vastus lateralis muscle decreased dramatically from the resting level immediately after the start of exercise at both altitudes. The Deff during exercise was significantly (p < 0.001 lower at 1800AL (60.4 ± 6.2 % than at near SL (74.4 ± 7.6 %. SpO2 during exercise was significantly (p < 0.001 lower at 1800AL (92.0 ± 1.7 % than at near SL (96.7 ± 1.2 %. Differences (SL - 1800AL in Deff during exercise correlated fairly strongly with differences in SpO2 during exercise (r = 0.660. These results suggested that acute exposure to moderate altitude caused a more dramatical decrease in peripheral muscle oxygenation during leg resistance exercise. It is salient to note, therefore , that peripheral muscle oxygenation status at moderate altitude could be evaluated using NIRcws and that moderate altitudes might be effectively used to apply hypoxic stress on peripheral muscles.
Ruf, Joseph H.; Jones, Daniel
2015-01-01
The dual-bell nozzle (fig. 1) is an altitude-compensating nozzle that has an inner contour consisting of two overlapped bells. At low altitudes, the dual-bell nozzle operates in mode 1, only utilizing the smaller, first bell of the nozzle. In mode 1, the nozzle flow separates from the wall at the inflection point between the two bell contours. As the vehicle reaches higher altitudes, the dual-bell nozzle flow transitions to mode 2, to flow full into the second, larger bell. This dual-mode operation allows near optimal expansion at two altitudes, enabling a higher mission average specific impulse (Isp) relative to that of a conventional, single-bell nozzle. Dual-bell nozzles have been studied analytically and subscale nozzle tests have been completed.1 This higher mission averaged Isp can provide up to a 5% increase2 in payload to orbit for existing launch vehicles. The next important step for the dual-bell nozzle is to confirm its potential in a relevant flight environment. Toward this end, NASA Marshall Space Flight Center (MSFC) and Armstrong Flight Research Center (AFRC) have been working to develop a subscale, hot-fire, dual-bell nozzle test article for flight testing on AFRC's F15-D flight test bed (figs. 2 and 3). Flight test data demonstrating a dual-bell ability to control the mode transition and result in a sufficient increase in a rocket's mission averaged Isp should help convince the launch service providers that the dual-bell nozzle would provide a return on the required investment to bring a dual-bell into flight operation. The Game Changing Department provided 0.2 FTE to ER42 for this effort in 2014.
Altitude training considerations for the winter sport athlete.
Chapman, Robert F; Stickford, Jonathon L; Levine, Benjamin D
2010-03-01
Winter sports events routinely take place at low to moderate altitudes, and nearly all Winter Olympic Games have had at least one venue at an altitude >1000 m. The acute and chronic effects of altitude can have a substantial effect on performance outcomes. Acutely, the decline in oxygen delivery to working muscle decreases maximal oxygen uptake, negatively affecting performance in endurance events, such as cross-country skiing and biathlon. The reduction in air resistance at altitude can dramatically affect sports involving high velocities and technical skill components, such as ski jumping, speed skating, figure skating and ice hockey. Dissociation between velocity and sensations usually associated with work intensity (ventilation, metabolic signals in skeletal muscle and heart rate) may impair pacing strategy and make it difficult to determine optimal race pace. For competitions taking place at altitude, a number of strategies may be useful, depending on the altitude of residence of the athlete and ultimate competition altitude, as follows. First, allow extra time and practice (how much is yet undetermined) for athletes to adjust to the changes in projectile motion; hockey, shooting, figure skating and ski jumping may be particularly affected. These considerations apply equally in the reverse direction; that is, for athletes practising at altitude but competing at sea level. Second, allow time for acclimatization for endurance sports: 3-5 days if possible, especially for low altitude (500-2000 m); 1-2 weeks for moderate altitude (2000-3000 m); and at least 2 weeks if possible for high altitude (>3000 m). Third, increase exercise-recovery ratios as much as possible, with 1:3 ratio probably optimal, and consider more frequent substitutions for sports where this is allowed, such as ice hockey. Fourth, consider the use of supplemental O(2) on the sideline (ice hockey) or in between heats (skating and Alpine skiing) to facilitate recovery. For competitions at sea
Preacclimatization in hypoxic chambers for high altitude sojourns.
Küpper, Thomas E A H; Schöffl, Volker
2010-09-01
Since hypoxic chambers are more and more available, they are used for preacclimatization to prepare for sojourns at high altitude. Since there are different protocols and the data differ, there is no general consensus about the standard how to perform preacclimatization by simulated altitude. The paper reviews the different types of exposure and focuses on the target groups which may benefit from preacclimatization. Since data about intermittent hypoxia for some hours per day to reduce the incidence of acute mountain sickness differ, it is suggested to perform preacclimatization by sleeping some nights at a simulated altitude which follows the altitude profile of the "gold standard" for high altitude acclimatization.
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Shu-Ying eZhao
2016-04-01
Full Text Available The giant lobelias in East African mountains are good models for studying molecular mechanisms of adaptation to different altitudes. In this study, we generated RNA-seq data of a middle-altitude species Lobelia aberdarica and a high-altitude species L. telekii, followed by selective pressure estimation of their orthologous genes. Our aim was to explore the important genes potentially involved in adaptation to different altitudes. About 9.3 Gb of clean nucleotides, 167,929 – 170,534 unigenes with total lengths of 159,762,099 – 171,138,936 bp for each of the two species were generated. OrthoMCL method identified 3,049 1:1 orthologous genes (each species was represented by one ortholog. Estimations of non-synonymous to synonymous rate were performed using an approximate method and a maximum likelihood method in PAML. 85 orthologous genes were under positive selection. At least 8 of these genes are possibly involved in DNA repair, response to DNA damage and temperature stimulus, and regulation of gene expression, which hints on how giant lobelias adapt to high altitudinal environment that characterised by cold, low oxygen and strong ultraviolet radiation. The negatively selected genes are over-represented in Gene ontology terms of hydrolase, macromolecular complex assembly among others. This study sheds light on understanding the molecular mechanism of adaptation to different altitudes, and provides genomic resources for further studies of giant lobelias.
Shilajit: A panacea for high-altitude problems.
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.
Roach, Gregory D; Schmidt, Walter F; Aughey, Robert J; Bourdon, Pitre C; Soria, Rudy; Claros, Jesus C Jimenez; Garvican-Lewis, Laura A; Buchheit, Martin; Simpson, Ben M; Hammond, Kristal; Kley, Marlen; Wachsmuth, Nadine; Gore, Christopher J; Sargent, Charli
2013-12-01
Altitude exposure causes acute sleep disruption in non-athletes, but little is known about its effects in elite athletes. The aim of this study was to examine the effects of altitude on two groups of elite athletes, that is, sea-level natives and high-altitude natives. Sea-level natives were members of the Australian under-17 soccer team (n=14). High-altitude natives were members of a Bolivian under-20 club team (n=12). Teams participated in an 18-day (19 nights) training camp in Bolivia, with 6 nights at near sea level in Santa Cruz (430 m) and 13 nights at high altitude in La Paz (3600 m). Sleep was assessed on every day/night using activity monitors. The Australians' sleep was shorter, and of poorer quality, on the first night at altitude compared with sea level. Sleep quality returned to normal by the end of the first week at altitude, but sleep quantity had still not stabilised at its normal level after 2 weeks. The quantity and quality of sleep obtained by the Bolivians was similar, or greater, on all nights at altitude compared with sea level. The Australians tended to obtain more sleep than the Bolivians at sea level and altitude, but the quality of the Bolivians' sleep tended to be better than that of the Australians at altitude. Exposure to high altitude causes acute and chronic disruption to the sleep of elite athletes who are sea-level natives, but it does not affect the sleep of elite athletes who are high-altitude natives.
System for indicating fuel-efficient aircraft altitude
Gary, B. L. (Inventor)
1984-01-01
A method and apparatus are provided for indicating the altitude at which an aircraft should fly so the W/d ratio (weight of the aircraft divided by the density of air) more closely approaches the optimum W/d for the aircraft. A passive microwave radiometer on the aircraft is directed at different angles with respect to the horizon to determine the air temperature, and therefore the density of the air, at different altitudes. The weight of the aircraft is known. The altitude of the aircraft is changed to fly the aircraft at an altitude at which is W/d ratio more closely approaches the optimum W/d ratio for that aircraft.
Application of altitude/hypoxic training by elite athletes.
Wilber, Randall L
2007-09-01
At the Olympic level, differences in performance are typically less than 0.5%. This helps explain why many contemporary elite endurance athletes in summer and winter sport incorporate some form of altitude/hypoxic training within their year-round training plan, believing that it will provide the "competitive edge" to succeed at the Olympic level. The purpose of this paper is to describe the practical application of altitude/hypoxic training as used by elite athletes. Within the general framework of the paper, both anecdotal and scientific evidence will be presented relative to the efficacy of several contemporary altitude/hypoxic training models and devices currently used by Olympic-level athletes for the purpose of legally enhancing performance. These include the three primary altitude/hypoxic training models: 1) live high+train high (LH+TH), 2) live high+train low (LH+TL), and 3) live low+train high (LL+TH). The LH+TL model will be examined in detail and will include its various modifications: natural/terrestrial altitude, simulated altitude via nitrogen dilution or oxygen filtration, and hypobaric normoxia via supplemental oxygen. A somewhat opposite approach to LH+TL is the altitude/hypoxic training strategy of LL+TH, and data regarding its efficacy will be presented. Recently, several of these altitude/hypoxic training strategies and devices underwent critical review by the World Anti-Doping Agency (WADA) for the purpose of potentially banning them as illegal performance-enhancing substances/methods. This paper will conclude with an update on the most recent statement from WADA regarding the use of simulated altitude devices.
Respiratory Muscle Training and Exercise Endurance at Altitude.
Helfer, Samuel; Quackenbush, Joseph; Fletcher, Michael; Pendergast, David R
2016-08-01
Climbing and trekking at altitude are common recreational and military activities. Physiological effects of altitude are hypoxia and hyperventilation. The hyperventilatory response to altitude may cause respiratory muscle fatigue and reduce sustained submaximal exercise. Voluntary isocapnic hyperpnea respiratory muscle training (VIHT) improves exercise endurance at sea level and at depth. The purpose of this study was to test the hypothesis that VIHT would improve exercise time at altitude [3600 m (11,811 ft)] compared to control and placebo groups. Subjects pedaled an ergometer until exhaustion at simulated altitude in a hypobaric chamber while noninvasive arterial saturation (Sao2), ventilation (VE), and oxygen consumption (Vo2) were measured. As expected, Sao2 decreased to 88 ± 4% saturation at rest and to 81 ± 2% during exercise, and was not affected by VIHT. VIHT resulted in a 40% increase in maximal training VE compared to pre-VIHT. Exercise endurance significantly increased 44% after VIHT (P = altitude post-VIHT increased more (49%) for longer (21 min) and decreased less (11% at 25.4 ± 6.7 min). VIHT improved exercise time at altitude and sustained VE. This suggests that VIHT reduced respiratory muscle fatigue and would be useful to trekkers and military personnel working at altitude. Helfer S, Quackenbush J, Fletcher M, Pendergast DR. Respiratory muscle training and exercise endurance at altitutde. Aerosp Med Hum Perform. 2016; 87(8):704-711.
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
Can High Altitude Influence Cytokines and Sleep?
Directory of Open Access Journals (Sweden)
Valdir de Aquino Lemos
2013-01-01
Full Text Available The number of persons who relocate to regions of high altitude for work, pleasure, sport, or residence increases every year. It is known that the reduced supply of oxygen (O2 induced by acute or chronic increases in altitude stimulates the body to adapt to new metabolic challenges imposed by hypoxia. Sleep can suffer partial fragmentation because of the exposure to high altitudes, and these changes have been described as one of the responsible factors for the many consequences at high altitudes. We conducted a review of the literature during the period from 1987 to 2012. This work explored the relationships among inflammation, hypoxia and sleep in the period of adaptation and examined a novel mechanism that might explain the harmful effects of altitude on sleep, involving increased Interleukin-1 beta (IL-1β, Interleukin-6 (IL-6, and tumor necrosis factor-alpha (TNF-α production from several tissues and cells, such as leukocytes and cells from skeletal muscle and brain.
Can High Altitude Influence Cytokines and Sleep?
de Aquino Lemos, Valdir; dos Santos, Ronaldo Vagner Thomatieli; Lira, Fabio Santos; Rodrigues, Bruno; Tufik, Sergio; de Mello, Marco Tulio
2013-01-01
The number of persons who relocate to regions of high altitude for work, pleasure, sport, or residence increases every year. It is known that the reduced supply of oxygen (O2) induced by acute or chronic increases in altitude stimulates the body to adapt to new metabolic challenges imposed by hypoxia. Sleep can suffer partial fragmentation because of the exposure to high altitudes, and these changes have been described as one of the responsible factors for the many consequences at high altitudes. We conducted a review of the literature during the period from 1987 to 2012. This work explored the relationships among inflammation, hypoxia and sleep in the period of adaptation and examined a novel mechanism that might explain the harmful effects of altitude on sleep, involving increased Interleukin-1 beta (IL-1β), Interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) production from several tissues and cells, such as leukocytes and cells from skeletal muscle and brain. PMID:23690660
Acute high-altitude illness | Hofmeyr | South African Medical Journal
African Journals Online (AJOL)
A substantial proportion of South Africa (SA)'s population lives at high altitude (>1 500 m), and many travel to very high altitudes (>3 500 m) for tourism, business, recreation or religious pilgrimages every year. Despite this, knowledge of acute altitude illnesses is poor among SA doctors. At altitude, the decreasing ambient ...
DLR HABLEG- High Altitude Balloon Launched Experimental Glider
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.
Directory of Open Access Journals (Sweden)
P. Rodríguez
2010-09-01
Full Text Available
RESUMEN
Dieciséis sujetos varones y sanos (VO2max de 4,06 ± 0,7 l.min-1, fueron sometidos a un protocolo incremental máximo en sendas condiciones de normoxia (N y altitud aguda moderada (Alt en días diferentes. La percepción subjetiva de esfuerzo (RPE y demás parámetros máximos y los relacionados con el umbral de lactato (UL, fueron registrados y comparados entre ambas condiciones. No se observaron diferencias significativas entre los RPEL, RPEC y RPET entre ambas condiciones ni para la máxima capacidad de trabajo ni en el UL. Tampoco se observaron cambios significativos en las potencias de trabajo, VO2 (l.min-1, Ve (l.min-1 y Lac (mMol.l-1 a las intensidades estudiadas. Sin embargo, aunque la Fc registrada al UL no mostró diferencias con la obtenida en Alt, sí se observó una reducción importante en la Fc a la máxima carga de trabajo alcanzada en condiciones de hipoxia (188 ± 9 vs 182 ± 7 ppm para una p<0.001. El ascenso súbito a una altitud moderada no altera la percepción subjetiva de esfuerzo en el UL ni a la máxima capacidad de trabajo. En estas condiciones, la Fc no se muestra tan buen indicador de la intensidad de ejercicio como la percepción de esfuerzo.
PALABRAS CLAVE: RPE, altitud, hipoxia, umbral láctico.
ABSTRACT
Sixteen healthy males, were submitted to a maximum incremental test in conditions of normoxia (N and of moderate acute altitude (Alt in two different days. Rating of perceived exertion (RPE, respiratory data, heart rate and lactate were measured during the test. The values at maximum work and at the lactate thresold (LT were compared between both conditions. Meaningful differences between the work, RPE, VO2 (l.min-1, Ve (l.min-1 y Lac (mMol.l-1 were not observed at
Numerical simulation of altitude impact on pulverized coal combustion
Energy Technology Data Exchange (ETDEWEB)
Pei, Xiaohui; He, Boshu; Ling, Ling; Wang, Lei [Beijing Jiaotong Univ., Beijing (China). Inst. of Mechanical, Electronic and Control Engineering
2013-07-01
A drop-tube Furnace simulation model has been developed to investigate the pulverized coal combustion characteristics under different altitudes using the commercially available software Fluent. The altitude conditions of 0, 500, 1,000, 1,500 m have been discussed. The results included the fields of temperature, pressure, velocity, the coal burnout, CO burnout and NO emission in the tube furnace. The variation of these parameters with altitude has been analyzed. The coal combustion characteristics were affected by the altitude. The time and space for coal burnout should be increased with the rise of altitude. The valuable results could be referenced in the design of coal- fired furnaces for the high altitude areas.
Altitude variations of ionospheric currents at auroral latitudes
International Nuclear Information System (INIS)
Kamide, Y.; Brekke, A.
1993-01-01
On the basis of updated EISCAT experiments, the first full derivation of the ionospheric current density of the auroral electrojets at six different altitudes are presented. It is found that current vectors at different altitudes are quite different, although the eastward and westward currents prevail in the evening and morning sectors, respectively, once the currents are integrated over altitude. The eastward electrojet becomes almost northward whilst the westward electrojet becomes almost southward, at the highest altitude, 125 km, in this study. The physical implications of these characteristics are discussed
Effects of ascent to high altitude on human antimycobacterial immunity.
Directory of Open Access Journals (Sweden)
Sarah Eisen
Full Text Available Tuberculosis infection, disease and mortality are all less common at high than low altitude and ascent to high altitude was historically recommended for treatment. The immunological and mycobacterial mechanisms underlying the association between altitude and tuberculosis are unclear. We studied the effects of altitude on mycobacteria and antimycobacterial immunity.Antimycobacterial immunity was assayed in 15 healthy adults residing at low altitude before and after they ascended to 3400 meters; and in 47 long-term high-altitude residents. Antimycobacterial immunity was assessed as the extent to which participants' whole blood supported or restricted growth of genetically modified luminescent Bacille Calmette-Guérin (BCG mycobacteria during 96 hours incubation. We developed a simplified whole blood assay that could be used by a technician in a low-technology setting. We used this to compare mycobacterial growth in participants' whole blood versus positive-control culture broth and versus negative-control plasma.Measurements of mycobacterial luminescence predicted the number of mycobacterial colonies cultured six weeks later. At low altitude, mycobacteria grew in blood at similar rates to positive-control culture broth whereas ascent to high altitude was associated with restriction (p ≤ 0.002 of mycobacterial growth to be 4-times less than in culture broth. At low altitude, mycobacteria grew in blood 25-times more than negative-control plasma whereas ascent to high altitude was associated with restriction (p ≤ 0.01 of mycobacterial growth to be only 6-times more than in plasma. There was no evidence of differences in antimycobacterial immunity at high altitude between people who had recently ascended to high altitude versus long-term high-altitude residents.An assay of luminescent mycobacterial growth in whole blood was adapted and found to be feasible in low-resource settings. This demonstrated that ascent to or residence at high altitude was
Altitude Registration of Limb-Scattered Radiation
Moy, Leslie; Bhartia, Pawan K.; Jaross, Glen; Loughman, Robert; Kramarova, Natalya; Chen, Zhong; Taha, Ghassan; Chen, Grace; Xu, Philippe
2017-01-01
One of the largest constraints to the retrieval of accurate ozone profiles from UV backscatter limb sounding sensors is altitude registration. Two methods, the Rayleigh scattering attitude sensing (RSAS) and absolute radiance residual method (ARRM), are able to determine altitude registration to the accuracy necessary for long-term ozone monitoring. The methods compare model calculations of radiances to measured radiances and are independent of onboard tracking devices. RSAS determines absolute altitude errors, but, because the method is susceptible to aerosol interference, it is limited to latitudes and time periods with minimal aerosol contamination. ARRM, a new technique introduced in this paper, can be applied across all seasons and altitudes. However, it is only appropriate for relative altitude error estimates. The application of RSAS to Limb Profiler (LP) measurements from the Ozone Mapping and Profiler Suite (OMPS) on board the Suomi NPP (SNPP) satellite indicates tangent height (TH) errors greater than 1 km with an absolute accuracy of +/-200 m. Results using ARRM indicate a approx. 300 to 400m intra-orbital TH change varying seasonally +/-100 m, likely due to either errors in the spacecraft pointing or in the geopotential height (GPH) data that we use in our analysis. ARRM shows a change of approx. 200m over 5 years with a relative accuracy (a long-term accuracy) of 100m outside the polar regions.
2010-11-02
... of Attainment by the Applicable Attainment Date for the Hayden, Nogales, Paul Spur/Douglas PM 10... proposes to determine that the Hayden, Nogales, and Paul Spur/Douglas nonattainment areas in Arizona... Hayden, Nogales and Paul Spur/Douglas nonattainment areas are not currently attaining the PM 10 standard...
High-altitude adaptations in vertebrate hemoglobins
DEFF Research Database (Denmark)
Weber, Roy E.
2007-01-01
Vertebrates at high altitude are subjected to hypoxic conditions that challenge aerobic metabolism. O2 transport from the respiratory surfaces to tissues requires matching between the O2 loading and unloading tensions and theO2-affinity of blood, which is an integrated function of hemoglobin......, birds and ectothermic vertebrates at high altitude....
Altitude Training in Elite Swimmers for Sea Level Performance (Altitude Project).
Rodríguez, Ferran A; Iglesias, Xavier; Feriche, Belén; Calderón-Soto, Carmen; Chaverri, Diego; Wachsmuth, Nadine B; Schmidt, Walter; Levine, Benjamin D
2015-09-01
This controlled, nonrandomized, parallel-groups trial investigated the effects on performance, V˙O2 and hemoglobin mass (tHbmass) of four preparatory in-season training interventions: living and training at moderate altitude for 3 and 4 wk (Hi-Hi3, Hi-Hi), living high and training high and low (Hi-HiLo, 4 wk), and living and training at sea level (SL) (Lo-Lo, 4 wk). From 61 elite swimmers, 54 met all inclusion criteria and completed time trials over 50- and 400-m crawl (TT50, TT400), and 100 (sprinters) or 200 m (nonsprinters) at best stroke (TT100/TT200). Maximal oxygen uptake (V˙O2max) and HR were measured with an incremental 4 × 200 m test. Training load was estimated using cumulative training impulse method and session RPE. Initial measures (PRE) were repeated immediately (POST) and once weekly on return to SL (PostW1 to PostW4). tHbmass was measured in duplicate at PRE and once weekly during the camp with CO rebreathing. Effects were analyzed using mixed linear modeling. TT100 or TT200 was worse or unchanged immediately at POST, but improved by approximately 3.5% regardless of living or training at SL or altitude after at least 1 wk of SL recovery. Hi-HiLo achieved greater improvement 2 (5.3%) and 4 wk (6.3%) after the camp. Hi-HiLo also improved more in TT400 and TT50 2 (4.2% and 5.2%, respectively) and 4 wk (4.7% and 5.5%) from return. This performance improvement was not linked linearly to changes in V˙O2max or tHbmass. A well-implemented 3- or 4-wk training camp may impair performance immediately but clearly improves performance even in elite swimmers after a period of SL recovery. Hi-HiLo for 4 wk improves performance in swimming above and beyond altitude and SL controls through complex mechanisms involving altitude living and SL training effects.
High altitude induced anorexia: effect of changes in leptin and oxidative stress levels.
Vats, Praveen; Singh, Vijay Kumar; Singh, Som Nath; Singh, Shashi Bala
2007-01-01
High altitude (HA) exposure usually leads to a significant weight loss in non-acclimatized humans. Anorexia is believed to be the main cause of this body weight loss. Appetite regulatory peptides, i.e. leptin and neuropeptide Y play a key role in food intake and energy homeostasis. Recent studies suggests increased oxidative stress during HA exposure. In present study effect of HA exposure on levels of leptin and NPY was evaluated along with N-acetyl cysteine (NAC) and vitamin E supplementation in relation to food intake and body weight changes. The study was conducted on 30 healthy male volunteers (age 19-29 years). Subjects were divided randomly into three groups of 10 each. Group 1 (placebo) supplemented with 400 mg of calcium gluconate, group 2 and 3 were supplemented with 400 mg of NAC and 400 mg vitamin E, respectively per day. The study was conducted at low altitude (320 m, Phase I), at HA 3600 m (Phase II) and at an altitude of 4580 m (Phase III). On HA exposure significant reduction in plasma leptin levels was observed in all the groups on day 2 (Phase II) along with decrease in food intake and reduction in body weight. Statistically significant increase in blood malondialdehyde (MDA) levels was seen in all the groups on HA exposure (Phase II, Day 2), but the maximum increase was in case of placebo group (65.1%) on day 2 (Phase II) in comparison to low altitude values. The decrease in energy intake was almost same in all the groups indicating that antioxidant supplementation did not provide any protection against HA anorexia. From the study, it may be concluded that leptin and oxidative stress possibly are not the key players for HA anorexia.
Directory of Open Access Journals (Sweden)
Jui-Lin eFan
2016-01-01
Full Text Available Previous studies reported enhanced cerebrovascular CO2 reactivity upon ascent to high altitude using linear models. However, there is evidence that this response may be sigmoidal in nature. Moreover, it was speculated that these changes at high altitude are mediated by alterations in acid-base buffering. Accordingly, we reanalyzed previously published data to assess middle cerebral blood flow velocity (MCAv responses to modified rebreathing at sea level (SL, upon ascent (ALT1 and following 16 days of acclimatization (ALT16 to 5,260 m in 21 lowlanders. Using sigmoid curve fitting of the MCAv responses to CO2, we found the amplitude (95% vs. 129%, SL vs. ALT1, 95% confidence intervals (CI [77, 112], [111, 145], respectively, P=0.024 and the slope of the sigmoid response (4.5 vs. 7.5 %/mmHg, SL vs. ALT1, 95% CIs [3.1, 5.9], [6.0, 9.0], respectively, P=0.026 to be enhanced at ALT1, which persisted with acclimatization at ALT16 (amplitude: 177%, 95% CI [139, 215], P<0.001; slope: 10.3 %/mmHg, 95% CI [8.2, 12.5], P=0.003 compared to SL. Meanwhile, the sigmoidal response midpoint was unchanged at ALT1 (SL: 36.5 mmHg; ALT1: 35.4 mmHg, 95% CIs [34.0, 39.0], [33.1, 37.7], respectively, P=0.982, while it was reduced by ~7 mmHg at ALT16 (28.6 mmHg, 95% CI [26.4, 30.8], P=0.001 vs. SL, indicating leftward shift of the cerebrovascular CO2 response to a lower arterial partial pressure of CO2 (PaCO2 following acclimatization to altitude. Sigmoid fitting revealed a leftward shift in the midpoint of the cerebrovascular response curve which could not be observed with linear fitting. These findings demonstrate that there is resetting of the cerebrovascular CO2 reactivity operating point to a lower PaCO2 following acclimatization to high altitude. This cerebrovascular resetting is likely the result of an altered acid-base buffer status resulting from prolonged exposure to the severe hypocapnia associated with ventilatory acclimatization to high altitude.
Directory of Open Access Journals (Sweden)
Andrew D Govus
Full Text Available To investigate the influence of daily oral iron supplementation on changes in hemoglobin mass (Hbmass and iron parameters after 2-4 weeks of moderate altitude exposure.Hematological data collected from 178 athletes (98 males, 80 females exposed to moderate altitude (1,350-3,000 m were analysed using linear regression to determine how altitude exposure combined with oral iron supplementation influenced Hbmass, total iron incorporation (TII and blood iron parameters [ferritin and transferrin saturation (TSAT].Altitude exposure (mean ± s: 21 ± 3 days increased Hbmass by 1.1% [-0.4, 2.6], 3.3% [1.7, 4.8], and 4.0% [2.0, 6.1] from pre-altitude levels in athletes who ingested nil, 105 mg and 210 mg respectively, of oral iron supplement daily. Serum ferritin levels decreased by -33.2% [-46.9, -15.9] and 13.8% [-32.2, 9.7] from pre-altitude levels in athletes who supplemented with nil and 105 mg of oral iron supplement daily, but increased by 36.8% [1.3, 84.8] in athletes supplemented with 210 mg of oral iron daily. Finally, athletes who ingested either 105 mg or 210 mg of oral iron supplement daily had a greater TII compared with non-supplemented athletes (0 versus 105 mg: effect size (d = -1.88 [-2.56, -1.17]; 0 versus 210 mg: effect size (d = -2.87 [-3.88, -1.66].Oral iron supplementation during 2-4 weeks of moderate altitude exposure may enhance Hbmass production and assist the maintenance of iron balance in some athletes with low pre-altitude iron stores.
Improving estimation of flight altitude in wildlife telemetry studies
Poessel, Sharon; Duerr, Adam E.; Hall, Jonathan C.; Braham, Melissa A.; Katzner, Todd
2018-01-01
Altitude measurements from wildlife tracking devices, combined with elevation data, are commonly used to estimate the flight altitude of volant animals. However, these data often include measurement error. Understanding this error may improve estimation of flight altitude and benefit applied ecology.There are a number of different approaches that have been used to address this measurement error. These include filtering based on GPS data, filtering based on behaviour of the study species, and use of state-space models to correct measurement error. The effectiveness of these approaches is highly variable.Recent studies have based inference of flight altitude on misunderstandings about avian natural history and technical or analytical tools. In this Commentary, we discuss these misunderstandings and suggest alternative strategies both to resolve some of these issues and to improve estimation of flight altitude. These strategies also can be applied to other measures derived from telemetry data.Synthesis and applications. Our Commentary is intended to clarify and improve upon some of the assumptions made when estimating flight altitude and, more broadly, when using GPS telemetry data. We also suggest best practices for identifying flight behaviour, addressing GPS error, and using flight altitudes to estimate collision risk with anthropogenic structures. Addressing the issues we describe would help improve estimates of flight altitude and advance understanding of the treatment of error in wildlife telemetry studies.
Acute and Chronic Altitude-Induced Cognitive Dysfunction in Children and Adolescents.
Rimoldi, Stefano F; Rexhaj, Emrush; Duplain, Hervé; Urben, Sébastien; Billieux, Joël; Allemann, Yves; Romero, Catherine; Ayaviri, Alejandro; Salinas, Carlos; Villena, Mercedes; Scherrer, Urs; Sartori, Claudio
2016-02-01
To assess whether exposure to high altitude induces cognitive dysfunction in young healthy European children and adolescents during acute, short-term exposure to an altitude of 3450 m and in an age-matched European population permanently living at this altitude. We tested executive function (inhibition, shifting, and working memory), memory (verbal, short-term visuospatial, and verbal episodic memory), and speed processing ability in: (1) 48 healthy nonacclimatized European children and adolescents, 24 hours after arrival at high altitude and 3 months after return to low altitude; (2) 21 matched European subjects permanently living at high altitude; and (3) a matched control group tested twice at low altitude. Short-term hypoxia significantly impaired all but 2 (visuospatial memory and processing speed) of the neuropsychological abilities that were tested. These impairments were even more severe in the children permanently living at high altitude. Three months after return to low altitude, the neuropsychological performances significantly improved and were comparable with those observed in the control group tested only at low altitude. Acute short-term exposure to an altitude at which major tourist destinations are located induces marked executive and memory deficits in healthy children. These deficits are equally marked or more severe in children permanently living at high altitude and are expected to impair their learning abilities. Copyright © 2016 Elsevier Inc. All rights reserved.
Golladay, Richard L.; Gendler, Stanley L.
1947-01-01
An investigation has been conducted in the Cleveland altitude wind tunnel to determine the operational characteristics of the I-40 jet-propulsion engine over a range of pressure altitudes from 10,000 to 50,000 feet and ram-pressure ratios from 1.00 to 1.76. Engine operational data were obtained with the engine in the standard configuration and with various modifications of the fuel system, the electrical system, and the combustion chambers. The effects of altitude and airspeed on operating speed range, starting, windmilli.ng, acceleration, speed regulation, cooling, and vibration of the standard and modified engines were determined, and damage to parts was noted. Maximum engine speed was obtainable at all altitudes and airspeeds wi th each fuel-control system investigated. The minimum idling speed was raised by increases in altitude and airspeed. The lowest minimum stable speeds were obtained with the standard configuration using 40-gallon nozzles with individual metering plugs. The engine was started normally at altitudes as high as 20,000 feet with all of the fuel systems and ignition combinations except one. Ignition at 70,000 feet was difficult and, although successful ignition occurred, acceleration was slow and usually characterized by excessive tail-pipe temperature. During windmilling investigations of the engine equipped with the standard fuel system, the engine could not be started at ram-pressure ratios of 1.1 to 1.7 at altitudes of 10,000, 20,000 and 30,000 feet. When equipped with the production barometric and Monarch 40-gallon nozzles, the engine accelerated in 12 seconds from an engine speed of 6000 rpm to 11,000 rpm at 20,000 feet and an average tail-pipe temperature of 11000 F. At the same altitude and temperature, all the engine configurations had approximately the same rate of acceleration. The Woodward governor produced the safest accelerations, inasmuch as it could be adjusted to automatically prevent acceleration blow out. The engine speed was
Erich Regener and the ionisation maximum of the atmosphere
Carlson, P.; Watson, A. A.
2014-12-01
In the 1930s the German physicist Erich Regener (1881-1955) did important work on the measurement of the rate of production of ionisation deep under water and in the atmosphere. Along with one of his students, Georg Pfotzer, he discovered the altitude at which the production of ionisation in the atmosphere reaches a maximum, often, but misleadingly, called the Pfotzer maximum. Regener was one of the first to estimate the energy density of cosmic rays, an estimate that was used by Baade and Zwicky to bolster their postulate that supernovae might be their source. Yet Regener's name is less recognised by present-day cosmic ray physicists than it should be, largely because in 1937 he was forced to take early retirement by the National Socialists as his wife had Jewish ancestors. In this paper we briefly review his work on cosmic rays and recommend an alternative naming of the ionisation maximum. The influence that Regener had on the field through his son, his son-in-law, his grandsons and his students, and through his links with Rutherford's group in Cambridge, is discussed in an appendix. Regener was nominated for the Nobel Prize in Physics by Schrödinger in 1938. He died in 1955 at the age of 73.
High-Altitude-Induced alterations in Gut-Immune Axis: A review.
Khanna, Kunjan; Mishra, K P; Ganju, Lilly; Kumar, Bhuvnesh; Singh, Shashi Bala
2018-03-04
High-altitude sojourn above 8000 ft is increasing day by day either for pilgrimage, mountaineering, holidaying or for strategic reasons. In India, soldiers are deployed to these high mountains for their duty or pilgrims visit to the holy places, which are located at very high altitude. A large population also resides permanently in high altitude regions. Every year thousands of pilgrims visit Holy cave of Shri Amarnath ji, which is above 15 000 ft. The poor acclimatization to high altitude may cause alteration in immunity. The low oxygen partial pressure may cause alterations in gut microbiota, which may cause changes in gut immunity. Effect of high altitude on gut-associated mucosal system is new area of research. Many studies have been carried out to understand the physiology and immunology behind the high-altitude-induced gut problems. Few interventions have also been discovered to circumvent the problems caused due to high-altitude conditions. In this review, we have discussed the effects of high-altitude-induced changes in gut immunity particularly peyer's patches, NK cells and inflammatory cytokines, secretary immunoglobulins and gut microbiota. The published articles from PubMed and Google scholar from year 1975 to 2017 on high-altitude hypoxia and gut immunity are cited in this review.
Maximum Work of Free-Piston Stirling Engine Generators
Kojima, Shinji
2017-04-01
Using the method of adjoint equations described in Ref. [1], we have calculated the maximum thermal efficiencies that are theoretically attainable by free-piston Stirling and Carnot engine generators by considering the work loss due to friction and Joule heat. The net work done by the Carnot cycle is negative even when the duration of heat addition is optimized to give the maximum amount of heat addition, which is the same situation for the Brayton cycle described in our previous paper. For the Stirling cycle, the net work done is positive, and the thermal efficiency is greater than that of the Otto cycle described in our previous paper by a factor of about 2.7-1.4 for compression ratios of 5-30. The Stirling cycle is much better than the Otto, Brayton, and Carnot cycles. We have found that the optimized piston trajectories of the isothermal, isobaric, and adiabatic processes are the same when the compression ratio and the maximum volume of the same working fluid of the three processes are the same, which has facilitated the present analysis because the optimized piston trajectories of the Carnot and Stirling cycles are the same as those of the Brayton and Otto cycles, respectively.
Spatial and temporal distribution of ionospheric currents-4: altitude ...
African Journals Online (AJOL)
(a) The continuous distribution of current density model reproduces the altitude distribution parameters of EEJ current density very well, (b) the altitude distribution parameters of EEJ current density in India and Peru are not significantly different and (c) The altitude distribution parameters of EEJ current density from rockets ...
Evaluation of Intensive Care Unit Ventilators at Altitude.
Blakeman, Thomas; Rodriquez, Dario; Petro, Michael; Branson, Richard
Devices may forgo US military air worthiness and safety testing in an attempt to expedite the availability of critical assets such as mechanical ventilators with a waiver for one-time use in extenuating circumstances. We evaluated two Intensive Care Unit (ICU) level ventilators: Drager Evita XL and Puritan Bennett (PB) 840 in an altitude chamber at sea level and altitudes of 8,000 and 16,000 feet. Altitude affected delivered tidal volumes (VTs) in volume control mode (VCV) and Pressure Regulated Volume Controlled (PRVC) mode at altitude with the Evita XL but the differences were not considered clinically important with the PB 840. Sixty-seven percent of the V T s were outside the ASTM standard of ± 10% of set V T with the Evita XL at altitude. The PB 840 did not deliver V T s that were larger than the ASTM standard up to an altitude of 16,000 feet while the majority of the delivered V T s with the Därger XL were greater than the ASTM standard. This could present a patient safety issue. Caregivers must be aware of the capabilities and limitations of ICU ventilators when utilized in a hypobaric environment in order to provide safe care. Copyright © 2017 Air Medical Journal Associates. All rights reserved.
A reference radiation facility for dosimetry at flight altitude and in space
Ferrari, A; Silari, Marco
2001-01-01
A reference facility for the intercomparison of active and passive detectors in high-energy neutron fields is available at CERN since 1993. A positive charged hadron beam (a mixture of protons and pions) with momentum of 120 GeV/c hits a copper target, 50 cm thick and 7 cm in diameter. The secondary particles produced in the interaction are filtered by a shielding of either 80 cm of concrete or 40 cm of iron. Behind the iron shielding, the resulting neutron spectrum has a maximum at about 1 MeV, with an additional high-energy component. Behind the concrete shielding, the neutron spectrum has a pronounced maximum at about 70 MeV and resembles the high-energy component of the radiation field created by cosmic rays at commercial flight altitudes. The facility is used for a variety of investigations with active and passive neutron dosimeters. Its use for measurements related to the space programme is discussed. (21 refs).
Stuttering Severity and Educational Attainment
O'Brian, Sue; Jones, Mark; Packman, Ann; Menzies, Ross; Onslow, Mark
2011-01-01
Purpose: This study investigated the relationship between self-reported stuttering severity ratings and educational attainment. Method: Participants were 147 adults seeking treatment for stuttering. At pretreatment assessment, each participant reported the highest educational level they had attained and rated their typical and worst stuttering…
Pathology of high altitude pulmonary oedema
International Nuclear Information System (INIS)
Saleem, N.
2014-01-01
Objective: To describe autopsy findings in fatal cases of high altitude pulmonary oedema. Study Design: Descriptive study. Place and Duration of Study: The study was carried out between 1999 and 2002 at an army field medical unit in Baltistan, Armed Forces Institute of Pathology, Rawalpindi and Army Medical College, Rawalpindi, Pakistan. Patients and Methods:Autopsies were performed in 17 fatal cases of High Altitude Pulmonary Edema (HAPE) occurring among soldiers serving in Siachen. Results:All cases were males with a mean age of 26.8 years (19-35). The mean altitude at which HAPE occurred was 5192 meters (2895-6492), and the mean duration of stay at these altitudes was 15.3 days (1-30). Eleven individuals had undergone proper acclimatization. The commonest clinical findings were cough (70%), dyspnoea (53%), nausea (47%), headache (41%), vomiting (35%), chest pain (35%) and tightness in chest (24%). Cyanosis and frothy secretions in the nostrils and mouth were present in all but one case. Mean combined weight of lungs was 1470 grams (1070-1810). There was marked congestion of outer and cut surfaces. Interstitial oedema was present in all cases. RBCs and leukocyte infiltrates were seen in 13 and alveolar hyaline membranes in 9 cases. Thrombi were seen in 2 cases. Cerebral oedema was present in 9 cases. Conclusion:HAPE can occur after more than two weeks of stay at high altitudes despite proper acclimatization. Concomitant cerebral oedema is frequently present. Our autopsy findings are consistent with what has been reported previously. (author)
Exercise and Training at Altitudes: Physiological Effects and Protocols
Directory of Open Access Journals (Sweden)
Olga Cecilia Vargas Pinilla
2014-01-01
Full Text Available An increase in altitude leads to a proportional fall in the barometric pressure, and a decrease in atmospheric oxygen pressure, producing hypobaric hypoxia that affects, in different degrees, all body organs, systems and functions. The chronically reduced partial pressure of oxygen causes that individuals adapt and adjust to physiological stress. These adaptations are modulated by many factors, including the degree of hypoxia related to altitude, time of exposure, exercise intensity and individual conditions. It has been established that exposure to high altitude is an environmental stressor that elicits a response that contributes to many adjustments and adaptations that influence exercise capacity and endurance performance. These adaptations include in crease in hemoglobin concentration, ventilation, capillary density and tissue myoglobin concentration. However, a negative effect in strength and power is related to a decrease in muscle fiber size and body mass due to the decrease in the training intensity. Many researches aim at establishing how training or living at high altitudes affects performance in athletes. Training methods, such as living in high altitudes training low, and training high-living in low altitudes have been used to research the changes in the physical condition in athletes and how the physiological adaptations to hypoxia can enhanceperformance at sea level. This review analyzes the literature related to altitude training focused on how physiological adaptations to hypoxic environments influence performance, and which protocols are most frequently used to train in high altitudes.
Effects of high altitude training on exercise capacity: fact or myth.
de Paula, Paula; Niebauer, Josef
2012-03-01
High altitude training has become a mainstay in endurance sports, with live high-train low as the current protocol of choice. Athletes either live or sleep in artificial or natural hypoxic conditions with the aim to increase serum erythropoietin concentrations, which are thought to improve maximum oxygen uptake and thus exercise performance. Changes, however, are not very striking and only apparent in so-called responders, who are not a well-defined group and may be as little as 50% of the trained study population. Whereas some studies show minor improvement, others report no change or even worsening. Furthermore, the mechanisms behind the proposed beneficial changes remain obscure and are far from being proven. There is an evident lack of sufficiently powered randomized, double-blinded studies, with training protocols that are identical for all groups and groups that are indeed comparable. Several studies discriminate between responders and non-responders, without clearly assessing the characteristics of the so-called responders. Until this has been done, it remains unclear if such a group really exists and how these subjects are characterized. This, however, would be of immense value, so protocols could be tailored to athletes' needs. Taken together, the current literature on natural or artificial hypoxia somewhat documents improved performance at high but not low altitude.
Observation of low energy particle precipitation at low altitude in the equatorial zone
Miah, M. A.
1989-01-01
Precipitation of protons in the equatorial zone was investigated by the Phoenix-1 experiment on the S81-1 mission from May to November, 1982. The protons show a precipitation peak along the line of minimum magnetic field strength with a FWHM of 13 deg. The index of equatorial pitch angle distribution is about 19. The peak proton flux shows a fifth-power altitude dependence, and the proton flux shows approximately a factor of 3 times increase in 1982 compared to that in 1969 due, possibly, to the stronger solar maximum conditions of 10.7-cm radiation in 1982.
Development and testing of airfoils for high-altitude aircraft
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.
Directory of Open Access Journals (Sweden)
Caroline Buss
2006-02-01
Full Text Available Quando o atleta ascende a uma grande altitude, ele é exposto a uma pressão barométrica reduzida, e os efeitos fisiológicos que acompanham estas mudanças da pressão atmosférica podem ter grande influência sobre o seu organismo e seu desempenho físico. Acredita-se que a hipóxia seja responsável pelo início de uma cascata de eventos sinalizadores que, ao final, levam à adaptação à altitude. A exposição aguda à hipóxia provoca sonolência, fadiga mental e muscular e prostração. Cefaléia, náusea e anorexia são sintomas provocados pela Doença Aguda das Montanhas, que pode ocorrer nos primeiros dias de permanência na altitude. Uma estratégia nutricional adequada é fundamental para que o organismo não sofra nenhum estresse adicional. O objetivo deste trabalho foi apresentar os principais efeitos da altitude sobre o organismo e sobre o desempenho físico, discutir e/ou sugerir recomendações nutricionais para esta situação e, se possível, apresentar uma orientação nutricional prática para o atleta na altitude. Algumas das principais conclusões encontradas foram: o consumo energético deve ser aumentado; é fundamental monitorar a quantidade de líquidos ingeridos e escolher alimentos agradáveis ao paladar, ricos em energia e nutrientes. Recomenda-se trabalhar com um nutricionista do esporte com antecedência, para que um plano alimentar individual seja elaborado e colocado em prática antes mesmo da viagem à altitude.When athletes are subject to high altitudes, they are exposed to a lower barometric pressure and the physiological effects that accompany these atmospheric pressure changes can have a strong influence on their bodies and performance. Hypoxia is thought to be responsible for triggering a cascade of signaling events that eventually leads to altitude acclimatization. Acute exposure to hypoxia causes sleepiness, mental and muscle fatigue and prostration. Headache, nausea and anorexia are some of the
Three dimensional winds: A maximum cross-correlation application to elastic lidar data
Energy Technology Data Exchange (ETDEWEB)
Buttler, William Tillman [Univ. of Texas, Austin, TX (United States)
1996-05-01
Maximum cross-correlation techniques have been used with satellite data to estimate winds and sea surface velocities for several years. Los Alamos National Laboratory (LANL) is currently using a variation of the basic maximum cross-correlation technique, coupled with a deterministic application of a vector median filter, to measure transverse winds as a function of range and altitude from incoherent elastic backscatter lidar (light detection and ranging) data taken throughout large volumes within the atmospheric boundary layer. Hourly representations of three-dimensional wind fields, derived from elastic lidar data taken during an air-quality study performed in a region of complex terrain near Sunland Park, New Mexico, are presented and compared with results from an Environmental Protection Agency (EPA) approved laser doppler velocimeter. The wind fields showed persistent large scale eddies as well as general terrain-following winds in the Rio Grande valley.
Enhancing team-sport athlete performance: is altitude training relevant?
Billaut, François; Gore, Christopher J; Aughey, Robert J
2012-09-01
Field-based team sport matches are composed of short, high-intensity efforts, interspersed with intervals of rest or submaximal exercise, repeated over a period of 60-120 minutes. Matches may also be played at moderate altitude where the lower oxygen partial pressure exerts a detrimental effect on performance. To enhance run-based performance, team-sport athletes use varied training strategies focusing on different aspects of team-sport physiology, including aerobic, sprint, repeated-sprint and resistance training. Interestingly, 'altitude' training (i.e. living and/or training in O(2)-reduced environments) has only been empirically employed by athletes and coaches to improve the basic characteristics of speed and endurance necessary to excel in team sports. Hypoxia, as an additional stimulus to training, is typically used by endurance athletes to enhance performance at sea level and to prepare for competition at altitude. Several approaches have evolved in the last few decades, which are known to enhance aerobic power and, thus, endurance performance. Altitude training can also promote an increased anaerobic fitness, and may enhance sprint capacity. Therefore, altitude training may confer potentially-beneficial adaptations to team-sport athletes, which have been overlooked in contemporary sport physiology research. Here, we review the current knowledge on the established benefits of altitude training on physiological systems relevant to team-sport performance, and conclude that current evidence supports implementation of altitude training modalities to enhance match physical performances at both sea level and altitude. We hope that this will guide the practice of many athletes and stimulate future research to better refine training programmes.
The Study of a Super Low Altitude Satellite
Noda, Atsushi; Homma, Masanori; Utashima, Masayoshi
This paper reports the result of a study for super low altitude satellite. The altitude of this satellite's orbit is lower than ever. The altitude of a conventional earth observing satellite is generally around from 600km to 900km. The lowest altitude of earth observing satellite launched in Japan was 350km; the Tropical Rainfall Measuring Mission (TRMM). By comparison, the satellite reported in this paper is much lower than that and it is planned to orbit below 200km. Furthermore, the duration of the flight planned is more than two years. Any satellite in the world has not achieved to keep such a low altitude that long term. The satellite in such a low orbit drops quickly because of the strong air drag. Our satellite will cancel the air drag effect by ion engine thrust. To realize this idea, a drag-free system will be applied. This usually leads a complicated and expensive satellite system. We, however, succeeded in finding a robust control law for a simple system even under the unpredictable change of air drag. When the altitude of the satellite is lowered successfully, the spatial resolution of an optical sensor can be highly improved. If a SAR is equipped with the satellite, it enables the drastic reduction of electric power consumption and the fabulous spatial resolution improvement at the same time.
[Hemoglobin and testosterone: importance on high altitude acclimatization and adaptation].
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.
Exercise capacity and selected physiological factors by ancestry and residential altitude
DEFF Research Database (Denmark)
Bianba; Berntsen, Sveinung; Andersen, Lars Bo
2014-01-01
AIM: Several physiological compensatory mechanisms have enabled Tibetans to live and work at high altitude, including increased ventilation and pulmonary diffusion capacity, both of which serve to increase oxygen transport in the blood. The aim of the present study was to compare exercise capacity...... Tibetans vs. Han Chinese may reflect a better adaptation to life at high altitude. Tibetans at the lower residential altitude of 3700 m demonstrated a better exercise capacity than residents at a higher altitude of 4300 m when measured at their respective residential altitudes. Such altitude- or ancestry...... (maximal power output) and selected physiological factors (arterial oxygen saturation and heart rate at rest and during maximal exercise, resting hemoglobin concentration, and forced vital capacity) in groups of native Tibetan children living at different residential altitudes (3700 vs. 4300 m above sea...
Development of a Compact High Altitude Imager and Sounding Radiometer (CHAISR)
Choi, R. K. Y.; Min, S.; Cho, Y. J.; Kim, K. H.; Ha, J. C.; Joo, S. W.
2017-12-01
Joint Civilian-Military Committee, under Advisory Council on Science and Technology, Korea, has approved a technology demonstration project for developing a lightweight HALE UAV (High-Altitude, Long Endurance). It aims to operate at lower stratosphere, i.e. altitude of 16 20 km, offering unique observational platform to atmospheric research community as pseudo-satellite. NIMS (National Institute of Meteorological Sciences, Korea) is responsible for a payload for atmospheric science, a Compact High Altitude Imager and Sounding Radiometer (CHAISR) to demonstrate scientific observations at lower stratosphere in the interest of improving numerical weather prediction model. CHAISR consists of three microwave radiometers (MWR) with 16 channel, and medium resolution cameras operating in a visible and infrared spectrum. One of the technological challenges for CHAISR is to accommodate those instruments within 50 W of power consumption. CHAISR will experience temperature up to -75°C, while pressure as low as 50 hPa at operational altitude. It requires passive thermal control of the payload to keep electronic subsystems warm enough for instrument operation with minimal power available. Safety features, such as payload power management and thermal control, are considered with minimal user input. Three radiometers measure atmospheric brightness temperature at frequency at around 20, 40, and 50 GHz. Retrieval process yields temperature and humidity profiles with cross track scan along the flight line. Estimated total weight of all radiometer hardware, from the antennas to data acquisition system, is less than 0.8 kg and a maximum power consumption is 15.2 W. With not enough power for blackbody calibration target, radiometers use zenith sky view at lower stratosphere as an excellent calibration target for a conventional tipping-curve calibration. Spatial distributions of clouds from visible and surface temperature from thermal cameras are used as additional information for
Spatio-temporal observations of the tertiary ozone maximum
Directory of Open Access Journals (Sweden)
V. F. Sofieva
2009-07-01
Full Text Available We present spatio-temporal distributions of the tertiary ozone maximum (TOM, based on GOMOS (Global Ozone Monitoring by Occultation of Stars ozone measurements in 2002–2006. The tertiary ozone maximum is typically observed in the high-latitude winter mesosphere at an altitude of ~72 km. Although the explanation for this phenomenon has been found recently – low concentrations of odd-hydrogen cause the subsequent decrease in odd-oxygen losses – models have had significant deviations from existing observations until recently. Good coverage of polar night regions by GOMOS data has allowed for the first time to obtain spatial and temporal observational distributions of night-time ozone mixing ratio in the mesosphere.
The distributions obtained from GOMOS data have specific features, which are variable from year to year. In particular, due to a long lifetime of ozone in polar night conditions, the downward transport of polar air by the meridional circulation is clearly observed in the tertiary ozone maximum time series. Although the maximum tertiary ozone mixing ratio is achieved close to the polar night terminator (as predicted by the theory, TOM can be observed also at very high latitudes, not only in the beginning and at the end, but also in the middle of winter. We have compared the observational spatio-temporal distributions of the tertiary ozone maximum with that obtained using WACCM (Whole Atmosphere Community Climate Model and found that the specific features are reproduced satisfactorily by the model.
Since ozone in the mesosphere is very sensitive to HOx concentrations, energetic particle precipitation can significantly modify the shape of the ozone profiles. In particular, GOMOS observations have shown that the tertiary ozone maximum was temporarily destroyed during the January 2005 and December 2006 solar proton events as a result of the HOx enhancement from the increased ionization.
Dietary Recommendations for Cyclists during Altitude Training
Michalczyk, Małgorzata; Czuba, Miłosz; Zydek, Grzegorz; Zając, Adam; Langfort, Józef
2016-01-01
The concept of altitude or hypoxic training is a common practice in cycling. However, several strategies for training regimens have been proposed, like “live high, train high” (LH-TH), “live high, train low” (LH-TL) or “intermittent hypoxic training” (IHT). Each of them combines the effect of acclimatization and different training protocols that require specific nutrition. An appropriate nutrition strategy and adequate hydration can help athletes achieve their fitness and performance goals in this unfriendly environment. In this review, the physiological stress of altitude exposure and training will be discussed, with specific nutrition recommendations for athletes training under such conditions. However, there is little research about the nutrition demands of athletes who train at moderate altitude. Our review considers energetic demands and body mass or body composition changes due to altitude training, including respiratory and urinary water loss under these conditions. Carbohydrate intake recommendations and hydration status are discussed in detail, while iron storage and metabolism is also considered. Last, but not least the risk of increased oxidative stress under hypoxic conditions and antioxidant supplementation suggestions are presented. PMID:27322318
Dietary Recommendations for Cyclists during Altitude Training.
Michalczyk, Małgorzata; Czuba, Miłosz; Zydek, Grzegorz; Zając, Adam; Langfort, Józef
2016-06-18
The concept of altitude or hypoxic training is a common practice in cycling. However, several strategies for training regimens have been proposed, like "live high, train high" (LH-TH), "live high, train low" (LH-TL) or "intermittent hypoxic training" (IHT). Each of them combines the effect of acclimatization and different training protocols that require specific nutrition. An appropriate nutrition strategy and adequate hydration can help athletes achieve their fitness and performance goals in this unfriendly environment. In this review, the physiological stress of altitude exposure and training will be discussed, with specific nutrition recommendations for athletes training under such conditions. However, there is little research about the nutrition demands of athletes who train at moderate altitude. Our review considers energetic demands and body mass or body composition changes due to altitude training, including respiratory and urinary water loss under these conditions. Carbohydrate intake recommendations and hydration status are discussed in detail, while iron storage and metabolism is also considered. Last, but not least the risk of increased oxidative stress under hypoxic conditions and antioxidant supplementation suggestions are presented.
Directory of Open Access Journals (Sweden)
M. P. Langowski
2015-01-01
Full Text Available Mg and Mg+ concentration fields in the upper mesosphere/lower thermosphere (UMLT region are retrieved from SCIAMACHY/Envisat limb measurements of Mg and Mg+ dayglow emissions using a 2-D tomographic retrieval approach. The time series of monthly mean Mg and Mg+ number density and vertical column density in different latitudinal regions are presented. Data from the limb mesosphere–thermosphere mode of SCIAMACHY/Envisat are used, which cover the 50 to 150 km altitude region with a vertical sampling of ≈3.3 km and latitudes up to 82°. The high latitudes are not observed in the winter months, because there is no dayglow emission during polar night. The measurements were performed every 14 days from mid-2008 until April 2012. Mg profiles show a peak at around 90 km altitude with a density between 750 cm−3 and 1500 cm−3. Mg does not show strong seasonal variation at latitudes below 40°. For higher latitudes the density is lower and only in the Northern Hemisphere a seasonal cycle with a summer minimum is observed. The Mg+ peak occurs 5–15 km above the neutral Mg peak altitude. These ions have a significant seasonal cycle with a summer maximum in both hemispheres at mid and high latitudes. The strongest seasonal variations of Mg+ are observed at latitudes between 20 and 40° and the density at the peak altitude ranges from 500 cm−3 to 4000 cm−3. The peak altitude of the ions shows a latitudinal dependence with a maximum at mid latitudes that is up to 10 km higher than the peak altitude at the equator. The SCIAMACHY measurements are compared to other measurements and WACCM model results. The WACCM results show a significant seasonal variability for Mg with a summer minimum, which is more clearly pronounced than for SCIAMACHY, and globally a higher peak density than the SCIAMACHY results. Although the peak density of both is not in agreement, the vertical column density agrees well, because SCIAMACHY and WACCM profiles have different
Does 'altitude training' increase exercise performance in elite athletes?
Lundby, Carsten; Robach, Paul
2016-07-01
What is the topic of this review? The aim is to evaluate the effectiveness of various altitude training strategies as investigated within the last few years. What advances does it highlight? Based on the available literature, the foundation to recommend altitude training to athletes is weak. Athletes may use one of the various altitude training strategies to improve exercise performance. The scientific support for such strategies is, however, not as sound as one would perhaps imagine. The question addressed in this review is whether altitude training should be recommended to elite athletes or not. © 2016 The Authors. Experimental Physiology © 2016 The Physiological Society.
Effect of oxygen supplementation in a hatchery at high altitude and ...
African Journals Online (AJOL)
The objective of this study was to investigate the effect of oxygen supplementation on broiler eggs in a hatchery at high altitude on the growth performance and ascites syndrome of broilers reared at low altitude. The treatment groups were low altitude with no oxygen supplemented in the hatchery (LA-NOX); high altitude with ...
Spatial patterns in Central Asian climate and equilibrium line altitudes
International Nuclear Information System (INIS)
Rupper, Summer; Koppes, Michele
2010-01-01
A suite of general circulation model (GCM) simulations and a glacier equilibrium line altitude (ELA) model are compared to reconstructed glacier advances from geomorphic data and used to test the sensitivity of Central Asian glaciers to simulated climate changes at the Last Glacial Maximum (LGM). Results highlight temperature changes as being the most important influence on glacier ELA changes during the LGM. With the exception of the southern Himalaya, for much of Central Asia there is consistency between GCMs for simulated LGM temperature changes, with a mean cooling of 4 0 C. Further research will necessarily need to focus on detailed analysis of the inter-model differences in temperature in the southern Himalaya, and acquiring additional paleoclimate proxies in the region in order to further constrain the GCMs.
2011-01-05
... Establishment of the Total Maximum Daily Load (TMDL) for the Chesapeake Bay AGENCY: Environmental Protection... that when met will assure the attainment and maintenance of all applicable water quality standards for... productive estuaries in the world. Despite significant efforts by federal, state, and local governments and...
Oxygen transport and cardiovascular function at extreme altitude: lessons from Operation Everest II
Sutton, J. R.; Reeves, J. T.; Groves, B. M.; Wagner, P. D.; Alexander, J. K.; Hultgren, H. N.; Cymerman, A.; Houston, C. S.
1992-01-01
Operation Everest II was designed to examine the physiological responses to gradual decompression simulating an ascent of Mt Everest (8,848 m) to an inspired PO2 of 43 mmHg. The principal studies conducted were cardiovascular, respiratory, muscular-skeletal and metabolic responses to exercise. Eight healthy males aged 21-31 years began the "ascent" and six successfully reached the "summit", where their resting arterial blood gases were PO2 = 30 mmHg and PCO2 = 11 mmHg, pH = 7.56. Their maximal oxygen uptake decreased from 3.98 +/- 0.2 L/min at sea level to 1.17 +/- 0.08 L/min at PIO2 43 mmHg. The principal factors responsible for oxygen transport from the atmosphere to tissues were (1) Alveolar ventilation--a four fold increase. (2) Diffusion from the alveolus to end capillary blood--unchanged. (3) Cardiac function (assessed by hemodynamics, echocardiography and electrocardiography)--normal--although maximum cardiac output and heart rate were reduced. (4) Oxygen extraction--maximal with PvO2 14.8 +/- 1 mmHg. With increasing altitude maximal blood and muscle lactate progressively declined although at any submaximal intensity blood and muscle lactate was higher at higher altitudes.
The CERN-EU radiation facility for dosimetry at flight altitude and in space
Ferrari, A; Silari, Marco
2001-01-01
A reference facility for the inter-comparison of active and passive detectors in complex high-energy neutron fields is available at CERN since 1993. A positively charged hadron beam (a mixture of protons and pions) with momentum of 120 GeV/c hits a copper target, 50 cm thick and 7 cm in diameter. The secondary particles produced in the interaction traverse a shield made of either 80 cm of concrete or 40 cm of iron. Behind the iron shield, the resulting neutron spectrum has a maximum at about 1 MeV, with an additional high-energy component. Behind the concrete shield, the neutron spectrum has a second pronounced maximum at about 70 MeV and resembles the high- energy component of the radiation field at commercial flight altitudes created by cosmic rays. Recent Monte Carlo calculations are presented, performed for different beam conditions and shielding configurations in view of a possible upgrade of the facility for measurements related to the space program. (20 refs).
Respiratory Muscle Training and Cognitive Function Exercising at Altitude.
Quackenbush, Joseph; Duquin, Aubrey; Helfer, Samuel; Pendergast, David R
2016-01-01
Hiking and trekking often occur at altitudes up to 12,000 ft altitude. The hypoxia-induced hyperventilation at altitude paradoxically reduces arterial CO2 (Paco2). A reduction in Paco2 results in vasoconstriction of the blood vessels of the brain and thus in local hypoxia. The local hypoxia likely affects cognitive function, which may result in reduced performance and altitude accidents. Recent publications have demonstrated that voluntary isocapnic hyperventilatory training of the respiratory muscles (VIHT) can markedly enhance exercise endurance as it is associated with reduced ventilation and its energy cost. VIHT may be useful in blunting the altitude-induced hyperventilation leading to higher Paco2 and improved cognitive function. This study examined the effects of VIHT, compared to control (C) and placebo (PVIHT) groups, on selected measures of executive functioning, including working memory and processing speed (i.e., Stroop Test, Symbol Digit Modalities Test, and Digit Span Forward) at simulated altitude up to 12,000 ft. Associated physiological parameters were also measured. The Digit Span Forward Test did not show improvements after VIHT in any group. The VIHT group, but not C or PVIHT groups, improved significantly (17-30%) on the Stroop Test. Similarly the VIHT group, but not the C and PVIHT groups, improved correct responses (26%) and number of attempts (24%) on the Symbol Digit Modalities Test. In addition, reaction time was also improved (16%). VIHT improved processing speed and working memory during exercise at altitude.
Cerebrovascular reactivity among native-raised high altitude residents: an fMRI study
Directory of Open Access Journals (Sweden)
Zhang Jiaxing
2011-09-01
Full Text Available Abstract Background The impact of long term residence on high altitude (HA on human brain has raised concern among researchers in recent years. This study investigated the cerebrovascular reactivity among native-born high altitude (HA residents as compared to native sea level (SL residents. The two groups were matched on the ancestral line, ages, gender ratios, and education levels. A visual cue guided maximum inspiration task with brief breath holding was performed by all the subjects while Blood-Oxygenation-Level-Dependent (BOLD functional Magnetic Resonance Imaging (fMRI data were acquired from them. Results Compared to SL controls, the HA group showed generally decreased cerebrovascular reactivity and longer delay in hemodynamic response. Clusters showing significant differences in the former aspect were located at the bilateral primary motor cortex, the right somatosensory association cortex, the right thalamus and the right caudate, the bilateral precuneus, the right cingulate gyrus and the right posterior cingulate cortex, as well as the left fusiform gyrus and the right lingual cortex; clusters showing significant differences in the latter aspect were located at the precuneus, the insula, the superior frontal and temporal gyrus, the somatosensory cortex (the postcentral gyrus and the cerebellar tonsil. Inspiratory reserve volume (IRV, which is an important aspect of pulmonary function, demonstrated significant correlation with the amount of BOLD signal change in multiple brain regions, particularly at the bilateral insula among the HA group. Conclusions Native-born HA residents generally showed reduced cerebrovascular reactivity as demonstrated in the hemodynamic response during a visual cue guided maximum inspiration task conducted with BOLD-fMRI. This effect was particularly manifested among brain regions that are typically involved in cerebral modulation of respiration.
2010-07-01
... Maximum for any 1 day Average of daily values for 30 consecutive days BOD5 8.0 4.0 TSS 10.0 5.0 pH (1) (1... Average of daily values for 30 consecutive days BOD5 8.7 4.35 TSS 11.0 5.5 pH (1) (1) 1 Within the range... degree of effluent reduction attainable by the application of the best practicable control technology...
Altitude valve for railway suspension control system
Zhang, Xuan; Zhang, Lihao; Li, Qingxuan; Chen, WanSong
2017-09-01
With the variation of people and material during vehicle service, the gravity of vehicle could be unbalanced. As a result it might cause accident. In order to solve this problem, altitude valve is assembled on board. It can adjust the gravity of vehicle by the intake and outlet progress of the spring in the altitude valve to prevent the tilt of vehicles.
Increased Hypoxic Dose After Training at Low Altitude with 9h Per Night at 3000m Normobaric Hypoxia
Directory of Open Access Journals (Sweden)
Amelia J. Carr, Philo U. Saunders, Brent S. Vallance, Laura A. Garvican-Lewis, Christopher J. Gore
2015-12-01
Full Text Available This study examined effects of low altitude training and a live-high: train-low protocol (combining both natural and simulated modalities on haemoglobin mass (Hbmass, maximum oxygen consumption (VO2max, time to exhaustion, and submaximal exercise measures. Eighteen elite-level race-walkers were assigned to one of two experimental groups; lowHH (low Hypobaric Hypoxia: continuous exposure to 1380 m for 21 consecutive days; n = 10 or a combined low altitude training and nightly Normobaric Hypoxia (lowHH+NHnight: living and training at 1380 m, plus 9 h.night-1 at a simulated altitude of 3000 m using hypoxic tents; n = 8. A control group (CON; n = 10 lived and trained at 600 m. Measurement of Hbmass, time to exhaustion and VO2max was performed before and after the training intervention. Paired samples t-tests were used to assess absolute and percentage change pre and post-test differences within groups, and differences between groups were assessed using a one-way ANOVA with least significant difference post-hoc testing. Statistical significance was tested at p < 0.05. There was a 3.7% increase in Hbmass in lowHH+NHnight compared with CON (p = 0.02. In comparison to baseline, Hbmass increased by 1.2% (±1.4% in the lowHH group, 2.6% (±1.8% in lowHH+NHnight, and there was a decrease of 0.9% (±4.9% in CON. VO2max increased by ~4% within both experimental conditions but was not significantly greater than the 1% increase in CON. There was a ~9% difference in pre and post-intervention values in time to exhaustion after lowHH+NH-night (p = 0.03 and a ~8% pre to post-intervention difference (p = 0.006 after lowHH only. We recommend low altitude (1380 m combined with sleeping in altitude tents (3000 m as one effective alternative to traditional altitude training methods, which can improve Hbmass.
Altitude variation of cosmic-ray neutrons
International Nuclear Information System (INIS)
Nakamura, T.; Uwamino, Y.; Ohkubo, T.; Hara, A.
1987-01-01
The altitude variation of the cosmic-ray neutron energy spectrum and the dose equivalent rate was measured at an average geomagnetic latitude of 24 degrees N by using the high-efficiency multi-sphere neutron spectrometer and neutron dose-equivalent counter developed by the authors. The data were obtained from a 2-h flight over Japan on 27 February 1985. The neutron energy spectra measured at sea level and at altitudes of 4880 m and at 11,280 m were compared with the calculated spectra of O'Brien and with other experimental spectra, and they are in moderately good agreement with them. The dose equivalent rate increases according to a quadratic curve up to about 6000 m and then increases linearly between 6000 m and 11,280 m. The dependence of dose equivalent rates at sea level and at an altitude of 12,500 m on geomagnetic latitude also is given by referring to other experimental results
The effect of altitude hypoxia on glucose homeostasis in men
DEFF Research Database (Denmark)
Larsen, J J; Hansen, J M; Olsen, Niels Vidiendal
1997-01-01
1. Exposure to altitude hypoxia elicits changes in glucose homeostasis with increases in glucose and insulin concentrations within the first few days at altitude. Both increased and unchanged hepatic glucose production (HGP) have previously been reported in response to acute altitude hypoxia...... (noradrenaline and adrenaline) and day 7 (adrenaline), but not at sea level. 4. In conclusion, insulin action decreases markedly in response to two days of altitude hypoxia, but improves with more prolonged exposure. HGP is always unchanged. The changes in insulin action may in part be explained by the changes...
APOLLO 16 COMMANDER JOHN YOUNG ENTERS ALTITUDE CHAMBER FOR TESTS
1971-01-01
Apollo 16 commander John W. Young prepares to enter the lunar module in an altitude chamber in the Manned Spacecraft Operations Building at the spaceport prior to an altitude run. During the altitude run, in which Apollo 16 lunar module pilot Charles M. Duke also participated, the chamber was pumped down to simulate pressure at an altitude in excess of 200,000 feet. Young, Duke and command module pilot Thomas K. Mattingly II, are training at the Kennedy Space Center for the Apollo 16 mission. Launch is scheduled from Pad 39A, March 17, 1972.
Cocozza, Claudia; Palombo, Caterina; Tognetti, Roberto; La Porta, Nicola; Anichini, Monica; Giovannelli, Alessio; Emiliani, Giovanni
2016-07-01
Seasonal analyses of cambial cell production and day-by-day stem radial increment can help to elucidate how climate modulates wood formation in conifers. Intra-annual dynamics of wood formation were determined with microcores and dendrometers and related to climatic signals in Norway spruce (Picea abies (L.) Karst.). The seasonal dynamics of these processes were observed at two sites of different altitude, Savignano (650 m a.s.l.) and Lavazè (1800 m a.s.l.) in the Italian Alps. Seasonal dynamics of cambial activity were found to be site specific, indicating that the phenology of cambial cell production is highly variable and plastic with altitude. There was a site-specific trend in the number of cells in the wall thickening phase, with the maximum cell production in early July (DOY 186) at Savignano and in mid-July (DOY 200) at Lavazè. The formation of mature cells showed similar trends at the two sites, although different numbers of cells and timing of cell differentiation were visible in the model shapes; at the end of ring formation in 2010, the number of cells was four times higher at Savignano (106.5 cells) than at Lavazè (26.5 cells). At low altitudes, microcores and dendrometers described the radial growth patterns comparably, though the dendrometer function underlined the higher upper asymptote of maximum growth in comparison with the cell production function. In contrast, at high altitude, these functions exhibited different trends. The best model was obtained by fitting functions of the Gompertz model to the experimental data. By combining radial growth and cambial activity indices we defined a model system able to synchronize these processes. Processes of adaptation of the pattern of xylogenesis occurred, enabling P. abies to occupy sites with contrasting climatic conditions. The use of daily climatic variables in combination with plant functional traits obtained by sensors and/or destructive sampling could provide a suitable tool to better
The maximum economic depth of groundwater abstraction for irrigation
Bierkens, M. F.; Van Beek, L. P.; de Graaf, I. E. M.; Gleeson, T. P.
2017-12-01
maximum economic depth will be combined with estimates of groundwater depth and storage coefficients to estimate economically attainable groundwater volumes worldwide.
Dietary Recommendations for Cyclists during Altitude Training
Directory of Open Access Journals (Sweden)
Małgorzata Michalczyk
2016-06-01
Full Text Available The concept of altitude or hypoxic training is a common practice in cycling. However, several strategies for training regimens have been proposed, like “live high, train high” (LH-TH, “live high, train low” (LH-TL or “intermittent hypoxic training” (IHT. Each of them combines the effect of acclimatization and different training protocols that require specific nutrition. An appropriate nutrition strategy and adequate hydration can help athletes achieve their fitness and performance goals in this unfriendly environment. In this review, the physiological stress of altitude exposure and training will be discussed, with specific nutrition recommendations for athletes training under such conditions. However, there is little research about the nutrition demands of athletes who train at moderate altitude. Our review considers energetic demands and body mass or body composition changes due to altitude training, including respiratory and urinary water loss under these conditions. Carbohydrate intake recommendations and hydration status are discussed in detail, while iron storage and metabolism is also considered. Last, but not least the risk of increased oxidative stress under hypoxic conditions and antioxidant supplementation suggestions are presented.
Brutsaert, Tom
Among high-altitude natives there is evidence of a general hypoxia tolerance leading to enhanced performance and/or increased capacity in several important domains. These domains likely include an enhanced physical work capacity, an enhanced reproductive capacity, and an ability to resist several common pathologies of chronic high-altitude exposure. The "strength" of the high-altitude native in this regard may have both a developmental and a genetic basis, although there is better evidence for the former (developmental effects) than for the latter. For example, early-life hypoxia exposure clearly results in lung growth and remodeling leading to an increased O2 diffusing capacity in adulthood. Genetic research has yet to reveal a population genetic basis for enhanced capacity in high-altitude natives, but several traits are clearly under genetic control in Andean and Tibetan populations e.g., resting and exercise arterial O2 saturation (SaO2). This chapter reviews the effects of nature and nurture on traits that are relevant to the process of gas exchange, including pulmonary volumes and diffusion capacity, the maximal oxygen consumption (VO2max), the SaO2, and the alveolar-arterial oxygen partial pressure difference (A-aDO2) during exercise.
Glucose Homeostasis During Short-term and Prolonged Exposure to High Altitudes
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
CAMEX-4 ER-2 HIGH ALTITUDE DROPSONDE V1
National Aeronautics and Space Administration — The CAMEX-4 ER-2 High Altitude Dropsonde dataset was collected by the ER-2 High Altitude Dropsonde System (EHAD), which used dropwinsondes fitted with Global...
Atmospheric electron flux at airplane altitude
International Nuclear Information System (INIS)
Enomoto, R.; Chiba, J.; Ogawa, K.; Sumiyoshi, T.; Takasaki, F.; Kifune, T.; Matsubara, Y.; Nishimura, J.
1991-01-01
We have developed a new detector to systematically measure the cosmic-ray electron flux at airplane altitudes. We loaded a lead-glass-based electron telescope onto a commercial cargo airplane. The first experiment was carried out using the air route between Narita (Japan) and Sydney (Australia); during this flight we measured the electron flux at various altitudes and latitudes. The thresholds of the electron energies were 1, 2, and 4 GeV. The results agree with a simple estimation using one-dimensional shower theory. A comparison with a Monte Carlo calculation was made
2011-01-11
... of Attainment by the Applicable Attainment Date for the Hayden, Nogales, Paul Spur/Douglas PM 10... making final determinations that the Hayden, Nogales, and Paul Spur/Douglas nonattainment areas in... the Clean Air Act, that three Arizona ``moderate'' PM 10 nonattainment areas (Hayden, Nogales, and...
Increase of cerebral blood flow at high altitude
DEFF Research Database (Denmark)
Lassen, N A
1992-01-01
but rather somewhat sharpened over five days at almost 4000 meters of altitude. This, along with other evidence, shows that CBF does not in itself adapt to chronic hypoxia. Nevertheless, a decrease in CBF is seen over days at constant altitude primarily due to increase in the hematocrit. The cerebral...
Sibship Size and Educational Attainment
DEFF Research Database (Denmark)
Jæger, Mads Meier
2009-01-01
have a negative effect on educational attainment most studies cannot distinguish empirically between the CM and the RDH. In this paper I use the different theoretical predictions in the CM and RDH on the role of cognitive ability as a partial or complete mediator of the effect of sibship size......Studies on family background often explain the negative effect of sibship size on educational attainment by one of two theories: the Confluence Model (CM) or the Resource Dilution Hypothesis (RDH). However, as both theories - for substantively different reasons - predict that sibship size should...... to distinguish the two theories and to identify a unique RDH effect on educational attainment. Using sibling data from the Wisconsin Longitudinal Study (WLS) and a random effect Instrumental Variable model I find that, in addition to a negative effect on cognitive ability, sibship size also has a strong negative...
High altitude pulmonary edema among "Amarnath Yatris"
Directory of Open Access Journals (Sweden)
Parvaiz A Koul
2013-01-01
Full Text Available Background: Annual pilgrimage (Yatra to the cave shrine of Shri Amarnath Ji′ is a holy ritual among the Hindu devotees of Lord Shiva. Located in the Himalayan Mountain Range (altitude 13,000 ft in south Kashmir, the shrine is visited by thousands of devotees and altitude sickness is reportedly common. Materials and Methods: More than 600,000 pilgrims visited the cave shrine in 2011 and 2012 with 239 recorded deaths. Thirty one patients with suspected altitude sickness were referred from medical centers en-route the cave to Sher-i-Kashmir Institute of Medical Sciences, a tertiary-care center in capital Srinagar (5,000 ft. The clinical features and the response to treatment were recorded. Results: Thirty-one patients (all lowlanders, 19 male; age 18-60 years, median 41 had presented with acute onset breathlessness of 1-4 days (median 1.9 d starting within 12-24 h of a rapid ascent; accompanied by cough (68%, headache (8%, dizziness and nausea (65%. Sixteen patients had associated encephalopathy. Clinical features on admission included tachypnea ( n = 31, tachycardia ( n = 23, bilateral chest rales ( n = 29, cyanosis ( n = 22 and grade 2-4 encephalopathy. Hypoxemia was demonstrable in 24 cases and bilateral infiltrates on radiologic imaging in 29. Ten patients had evidence of high-altitude cerebral edema. All patients were managed with oxygen, steroids, nifedipine, sildenafil and other supportive measures including invasive ventilation ( n = 3. Three patients died due to multiorgan dysfunction. Conclusions: Altitude sickness is common among Amaranath Yatris from the plains and appropriate educational strategies should be invoked for prevention and prompt treatment.
Computer vision techniques for rotorcraft low altitude flight
Sridhar, Banavar
1990-01-01
Rotorcraft operating in high-threat environments fly close to the earth's surface to utilize surrounding terrain, vegetation, or manmade objects to minimize the risk of being detected by an enemy. Increasing levels of concealment are achieved by adopting different tactics during low-altitude flight. Rotorcraft employ three tactics during low-altitude flight: low-level, contour, and nap-of-the-earth (NOE). The key feature distinguishing the NOE mode from the other two modes is that the whole rotorcraft, including the main rotor, is below tree-top whenever possible. This leads to the use of lateral maneuvers for avoiding obstacles, which in fact constitutes the means for concealment. The piloting of the rotorcraft is at best a very demanding task and the pilot will need help from onboard automation tools in order to devote more time to mission-related activities. The development of an automation tool which has the potential to detect obstacles in the rotorcraft flight path, warn the crew, and interact with the guidance system to avoid detected obstacles, presents challenging problems. Research is described which applies techniques from computer vision to automation of rotorcraft navigtion. The effort emphasizes the development of a methodology for detecting the ranges to obstacles in the region of interest based on the maximum utilization of passive sensors. The range map derived from the obstacle-detection approach can be used as obstacle data for the obstacle avoidance in an automatic guidance system and as advisory display to the pilot. The lack of suitable flight imagery data presents a problem in the verification of concepts for obstacle detection. This problem is being addressed by the development of an adequate flight database and by preprocessing of currently available flight imagery. The presentation concludes with some comments on future work and how research in this area relates to the guidance of other autonomous vehicles.
Altitude acclimatization and blood volume: effects of exogenous erythrocyte volume expansion
DEFF Research Database (Denmark)
Sawka, M N; Young, Jette Feveile; Rock, P B
1996-01-01
blood oxygen content alters erythropoietin responses during altitude acclimatization, and 4) mechanisms responsible for plasma loss at altitude. Sixteen healthy men had a series of hematologic measurements made at sea level, on the first and ninth days of altitude (4,300 m) residence, and after...
DEFF Research Database (Denmark)
Pouliot, Mariève; Pyakurel, Dipesh; Smith-Hall, Carsten
2018-01-01
Ethnopharmacological relevance Ophiocordyceps sinensis (Berk.) G.H.Sung, J.M.Sung, Hywel-Jones & Spatafora, a high altitude Himalayan fungus-caterpillar product found in alpine meadows in China, Bhutan, Nepal, and India, has been used in the Traditional Chinese Medicine system for over 2000 years...
2010-11-02
... of Attainment by the Applicable Attainment Date for the Hayden, Nogales, Paul Spur/Douglas PM 10...: EPA has determined that the Hayden, Nogales, and Paul Spur/ Douglas nonattainment areas in Arizona... of a review of more recent ambient monitoring data, EPA has determined that the Hayden, Nogales, and...
Exploring the Limits of High Altitude GPS for Future Lunar Missions
Ashman, Benjamin W.; Parker, Joel J. K.; Bauer, Frank H.; Esswein, Michael
2018-01-01
An increasing number of spacecraft are relying on the Global Positioning System (GPS) for navigation at altitudes near or above the GPS constellation itself - the region known as the Space Service Volume (SSV). While the formal definition of the SSV ends at geostationary altitude, the practical limit of high-altitude space usage is not known, and recent missions have demonstrated that signal availability is sufficient for operational navigation at altitudes halfway to the moon. This paper presents simulation results based on a high-fidelity model of the GPS constellation, calibrated and validated through comparisons of simulated GPS signal availability and strength with flight data from recent high-altitude missions including the Geostationary Operational Environmental Satellite 16 (GOES-16) and the Magnetospheric Multiscale (MMS) mission. This improved model is applied to the transfer to a lunar near-rectilinear halo orbit (NRHO) of the class being considered for the international Deep Space Gateway concept. The number of GPS signals visible and their received signal strengths are presented as a function of receiver altitude in order to explore the practical upper limit of high-altitude space usage of GPS.
International Nuclear Information System (INIS)
Kempf, Nicholas; Zhang, Yanliang
2016-01-01
Highlights: • A three-dimensional automotive thermoelectric generator (TEG) model is developed. • Heat exchanger design and TEG configuration are optimized for maximum fuel efficiency increase. • Heat exchanger conductivity has a strong influence on maximum fuel efficiency increase. • TEG aspect ratio and fin height increase with heat exchanger thermal conductivity. • A 2.5% fuel efficiency increase is attainable with nanostructured half-Heusler modules. - Abstract: Automotive fuel efficiency can be increased by thermoelectric power generation using exhaust waste heat. A high-temperature thermoelectric generator (TEG) that converts engine exhaust waste heat into electricity is simulated based on a light-duty passenger vehicle with a 4-cylinder gasoline engine. Strategies to optimize TEG configuration and heat exchanger design for maximum fuel efficiency improvement are provided. Through comparison of stainless steel and silicon carbide heat exchangers, it is found that both the optimal TEG design and the maximum fuel efficiency increase are highly dependent on the thermal conductivity of the heat exchanger material. Significantly higher fuel efficiency increase can be obtained using silicon carbide heat exchangers at taller fins and a longer TEG along the exhaust flow direction when compared to stainless steel heat exchangers. Accounting for major parasitic losses, a maximum fuel efficiency increase of 2.5% is achievable using newly developed nanostructured bulk half-Heusler thermoelectric modules.
Mobile platform of altitude measurement based on a smartphone
Roszkowski, Paweł; Kowalczyk, Marcin
2016-09-01
The article presents a low cost, fully - functional meter of altitude and pressure changes in a form of mobile application controlled by Android OS (operating system). The measurements are possible due to pressure sensor inserted in majority of latest modern mobile phones, which are known as smartphones. Using their computing capabilities and other equipment components like GPS receiver in connection with data from the sensor enabled authors to create a sophisticated handheld measuring platform with many unique features. One of them is a drawing altitude maps mode in which user can create maps of altitude changes just by moving around examined area. Another one is a convenient mode for altitude measurement. It is also extended with analysis tools which provide a possibility to compare measured values by displaying the data in a form of plots. The platform consists of external backup server, where the user can secure all gathered data. Moreover, the results of measurement's accuracy examination process which was executed after building the solution were shown. At the end, the realized meter of altitude was compared to other popular altimeters, which are available on the market currently.
The peak altitude of H3+ auroral emission: comparison with the ultraviolet
Blake, J.; Stallard, T.; Miller, S.; Melin, H.; O'Donoghue, J.; Baines, K.
2013-09-01
account for this, the acceptable error in misalignment was set to be ± 4 degrees. The accepted error range for the altitudinal profiles was set to ± 250 km. It was determined that variations in the measured altitude of the aurorae are predominantly shifted by misalignment, though there is also some natural variation. Using a second order polynomial fit, the altitude with zero misalignment is measured at 1215 ± 119 km. Further still, through comparison of the IR and UV altitudinal emission profiles is had been discovered that regardless of the alignment, the Infrared auroral altitudinal profile drops off in intensity much faster and the Ultraviolet counterpart, declining to less than 10% of maximum intensity before reaching an altitude of 2000 km above the 1 bar pressure surface. Further work is currently underway to investigate the implication for the emissive behaviour of H3 + with altitude.
2010-11-29
... ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 52 [R09-OAR-2010-0718; FRL-9233-1] Determinations of Attainment by the Applicable Attainment Date for the Hayden, Nogales, Paul Spur/Douglas PM10 Nonattainment... November 2, 2010 (75 FR 67220), direct final rule determining that the Hayden, Nogales, and Paul Spur...
McSharry, Patrick E
2007-12-22
To assess the effect of altitude on match results and physiological performance of a large and diverse population of professional athletes. Statistical analysis of international football (soccer) scores and results. FIFA extensive database of 1460 football matches in 10 countries spanning over 100 years. Altitude had a significant (Pnegative impact on physiological performance as revealed through the overall underperformance of low altitude teams when playing against high altitude teams in South America. High altitude teams score more and concede fewer goals with increasing altitude difference. Each additional 1000 m of altitude difference increases the goal difference by about half of a goal. The probability of the home team winning for two teams from the same altitude is 0.537, whereas this rises to 0.825 for a home team with an altitude difference of 3695 m (such as Bolivia v Brazil) and falls to 0.213 when the altitude difference is -3695 m (such as Brazil v Bolivia). Altitude provides a significant advantage for high altitude teams when playing international football games at both low and high altitudes. Lowland teams are unable to acclimatise to high altitude, reducing physiological performance. As physiological performance does not protect against the effect of altitude, better predictors of individual susceptibility to altitude illness would facilitate team selection.
Research progress on high altitude retinopathy and application of Traditional Chinese Medicine
Directory of Open Access Journals (Sweden)
Hai-Xiang Huang
2014-11-01
Full Text Available High altitude retinopathy(HARrefers to the body which can't adapt to the hypobaric hypoxia environment at high altitude leading to retinal diseases, which typically manifested as retinal hemorrhages, optic disc edema and cotton wool spots. With the development of high altitude medicine, HAR become a hot topic of eye research in recent years. New researches show a significantly higher incidence of HAR, and HAR has a close contact with acute mountain sickness, high altitude cerebral edema and high altitude pulmonary edema. A further study in pathogenesis and prevention measures of HAR will promote the prevention of altitude sickness. Traditional Chinese Medicine has achieved good effects in the prevention of altitude sickness, but the effect and mechanism of herbs on HAR has not been reported. Through read and summarize the relevant literatures and reports, the author will give an overview of the research advances on HAR's pathogenesis and application of Traditional Chinese Medicine.
Quadrant to Measure the Sun's Altitude
Windsor, A Morgan, Jr.
2013-01-01
The changing altitude of the Sun (either over the course of a day or longer periods) is a phenomenon that students do not normally appreciate. However, the altitude of the Sun affects many topics in disciplines as diverse as astronomy, meteorology, navigation, or horology, such as the basis for seasons, determination of latitude and longitude, or…
Hemoglobin and testosterone: importance on high altitude acclimatization and adaptation
Gonzales, Gustavo F.; Jefe de la Unidad de Reproducción, Instituto de Investigaciones de la Altura y Jefe del Laboratorio de Endocrinología y Reproducción, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia. Doctor en Medicina y Doctor en Ciencias. Especialista en Endocrinología.
2011-01-01
The different types of response mechanisms that the organism uses when exposed to hypoxia include accommodation, acclimatization and adaptation. Accommodation is the initial response to acute exposure to high altitude hypoxia and is characterized by an increase in ventilation and heart rate. Acclimatization is observed in individuals temporarily exposed to high altitude, and to some extent, it enables them to tolerate the high altitudes. In this phase, erythropoiesis is increased, resulti...
Experimental verification of altitude effect over thermal power in an atmospheric burner
International Nuclear Information System (INIS)
Amell Arrieta, Andres; Agudelo, John Ramiro; Cortes, Jaime
1992-01-01
Colombian national massive gasification plan is carried out in a variety of geographic altitudes ranging from 0 to 2.600 meter. The biggest market is located in the Andinan Region, which is characterized by great urban centres located at high altitudes. Commercial, domestic and industrial applications are characterized by the utilization of appliances using atmospheric burners. The thermal power of these burners is affected by altitude. This paper shows experimental results of thermal power reduction in atmospheric burners due to altitude changes. It was found that thermal power is reduced by 1,5% each 304 meters of altitude
Hemorrhages and hemostasis in guinea-pigs exposed to irradiation at high altitude
International Nuclear Information System (INIS)
Tartakovskij, V.N.; Daniyarov, S.B.
1988-01-01
Hemorrhagic intensity, hemostasis and blood vessel wall resistance to mechanical effects were studied in guinea-pigs exposed to whole-body irradiation (3.0 Gy). The animals were irradiated at low altitude (760 m above sea level) and at high altitude (3200 m above sea level) after 1 and 31 days of adaptation. It was demonstrated that hemorrhagic intensity in both groups of guinea-pigs irradiated at high altitude was significantly reduced in comparison with that at low altitude. The decrease of radiation-induced hemorrhages at high altitude is associated with less severe changes in thrombopoiesis, blood vessel wall and blood coagulation
Wallner, L. E.; Lubick, R. J.; Chelko, L. J.
1955-01-01
During an investigation of the J57-P-1 turbojet engine in the Lewis altitude wind tunnel, effects of inlet-flow distortion on engine stall characteristics and operating limits were determined. In addition to a uniform inlet-flow profile, the inlet-pressure distortions imposed included two radial, two circumferential, and one combined radial-circumferential profile. Data were obtained over a range of compressor speeds at an altitude of 50,000 and a flight Mach number of 0.8; in addition, the high- and low-speed engine operating limits were investigated up to the maximum operable altitude. The effect of changing the compressor bleed position on the stall and operating limits was determined for one of the inlet distortions. The circumferential distortions lowered the compressor stall pressure ratios; this resulted in less fuel-flow margin between steady-state operation and compressor stall. Consequently, the altitude operating Limits with circumferential distortions were reduced compared with the uniform inlet profile. Radial inlet-pressure distortions increased the pressure ratio required for compressor stall over that obtained with uniform inlet flow; this resulted in higher altitude operating limits. Likewise, the stall-limit fuel flows required with the radial inlet-pressure distortions were considerably higher than those obtained with the uniform inlet-pressure profile. A combined radial-circumferential inlet distortion had effects on the engine similar to the circumferential distortion. Bleeding air between the two compressors eliminated the low-speed stall limit and thus permitted higher altitude operation than was possible without compressor bleed.
Accuracy of Handheld Blood Glucose Meters at High Altitude
de Mol, Pieter; Krabbe, Hans G.; de Vries, Suzanna T.; Fokkert, Marion J.; Dikkeschei, Bert D.; Rienks, Rienk; Bilo, Karin M.; Bilo, Henk J. G.
2010-01-01
Background: Due to increasing numbers of people with diabetes taking part in extreme sports (e. g., high-altitude trekking), reliable handheld blood glucose meters (BGMs) are necessary. Accurate blood glucose measurement under extreme conditions is paramount for safe recreation at altitude. Prior
Directory of Open Access Journals (Sweden)
Xiaolong Tang
Full Text Available Metabolic response to high altitude remains poorly explored in reptiles. In the present study, the metabolic characteristics of Phrynocephaluserythrurus (Lacertilia: Agamidae, which inhabits high altitudes (4500 m and Phrynocephalusprzewalskii (Lacertilia: Agamidae, which inhabits low altitudes, were analysed to explore the metabolic regulatory strategies for lizards living at high-altitude environments. The results indicated that the mitochondrial respiratory rates of P. erythrurus were significantly lower than those of P. przewalskii, and that proton leak accounts for 74~79% of state 4 and 7~8% of state3 in P. erythrurus vs. 43~48% of state 4 and 24~26% of state3 in P. przewalskii. Lactate dehydrogenase (LDH activity in P. erythrurus was lower than in P. przewalskii, indicating that at high altitude the former does not, relatively, have a greater reliance on anaerobic metabolism. A higher activity related to β-hydroxyacyl coenzyme A dehydrogenase (HOAD and the HOAD/citrate synthase (CS ratio suggested there was a possible higher utilization of fat in P. erythrurus. The lower expression of PGC-1α and PPAR-γ in P. erythrurus suggested their expression was not influenced by cold and low PO2 at high altitude. These distinct characteristics of P. erythrurus are considered to be necessary strategies in metabolic regulation for living at high altitude and may effectively compensate for the negative influence of cold and low PO2.
Directory of Open Access Journals (Sweden)
Bruno Galvêas Laviola
2007-12-01
Full Text Available Dado à importância de se conhecer a exportação de micronutrientes pelos frutos, bem como, as épocas em que são mais demandados pelo cafeeiro, estudou-se o acúmulo de B, Cu, Fe, Mn e Zn em frutos de Coffea arabica L da antese à maturação, em lavouras estabelecidas em duas altitudes. Estudou-se também a variação no teor desses elementos. Estudou-se o acúmulo de B, Cu, Fe, Mn e Zn em frutos de cafeeiro arábico da antese à maturação em duas altitudes, bem como a variação na concentração dos elementos em folhas dos ramos produtivos. O experimento foi constituído da variedade de cafeeiro (Coffea arabica L. Catuaí IAC 44 cultivada a 720 e 950 m de altitude, no município de Martins Soares-MG. O delineamento experimental foi inteiramente ao acaso, com três repetições, usando um esquema de parcela subdividida no tempo. O aumento da altitude influenciou o ciclo reprodutivo do cafeeiro, demandando maior tempo para formação dos frutos. O consumo de nutrientes pelos frutos, assim como o enchimento de grãos, foi mais crítico em condições de menor altitude, já que a planta necessitou completar esses processos em menor espaço de tempo. No estádio de expansão rápida, a percentagem de acúmulo de micronutrientes foi maior na altitude de 720 m, comparada à de 950 m. De modo geral, a altitude influenciou a variação das concentrações foliares de nutrientes, apesar de não se ter observado resposta-padrão da concentração foliar ao aumento da altitude. Conclui-se que a altitude teve influência na extensão do ciclo, bem como no acúmulo de micronutrientes em frutos e na variação, das concentrações foliares destes elementos em folhas de cafeeiro.In view of the importance of knowing fruit micronutrients export from the soil, and the season in which its coffee-plant demand is higher, the accumulation of B, Cu, Fe, Mn and Zn in fruits as well as the variation in the leaf content of the elements in productive branches of
Woolcott, Orison O.; Gutierrez, Cesar; Castillo, Oscar A.; Elashoff, Robert M.; Stefanovski, Darko; Bergman, Richard N.
2015-01-01
Objective To determine the association between altitude and obesity in a nationally representative sample of the Peruvian adult population. Design and Methods This is a cross-sectional analysis of publicly available data from the Food and Nutrition National Center (CENAN, Peru), period 2009-2010. Prevalence ratio of obesity and abdominal obesity was determined as a measure of association. Obesity and abdominal obesity were diagnosed based on direct anthropometric measurements. Results The final dataset consisted of 31,549 individuals ≥20 years old. The prevalence ratio of obesity was as follows: 1.00 between 0–499 m (reference category), 1.00 (95% confidence interval 0.87-1.16) between 500–1,499 m, 0.74 (0.63-0.86) between 1,500–2,999, and 0.54 (0.45-0.64) at ≥3,000 m, adjusting for age, sex, self-reported physical activity, out-migration rate, urbanization, poverty, education, and geographical latitude and longitude. In the same order, the adjusted prevalence ratio of abdominal obesity was 1.00, 1.01 (0.94-1.07), 0.93 (0.87-0.99), and 0.89 (0.82-0.95), respectively. We found an interaction between altitude and sex and between altitude and age (P<0.001, for both interactions) on the association with obesity and abdominal obesity. Conclusions Among Peruvian adult individuals, we found an inverse association between altitude and obesity, adjusting for multiple covariates. This adjusted association varied by sex and age. PMID:26935008
Woolcott, Orison O; Gutierrez, Cesar; Castillo, Oscar A; Elashoff, Robert M; Stefanovski, Darko; Bergman, Richard N
2016-04-01
To determine the association between altitude and obesity in a nationally representative sample of the Peruvian adult population. This is a cross-sectional analysis of publicly available data from the Food and Nutrition National Center (CENAN, Peru), period 2009-2010. The Prevalence ratio of obesity and abdominal obesity was determined as a measure of association. Obesity and abdominal obesity were diagnosed based on direct anthropometric measurements. The final data set consisted of 31,549 individuals ≥20 years old. The prevalence ratio of obesity was as follows: 1.00 between 0 and 499 m (reference category), 1.00 (95% confidence interval 0.87-1.16) between 500-1,499 m, 0.74 (0.63-0.86) between 1,500-2,999 m, and 0.54 (0.45-0.64) at ≥3,000 m, adjusting for age, sex, self-reported physical activity, out-migration rate, urbanization, poverty, education, and geographical latitude and longitude. In the same order, the adjusted prevalence ratio of abdominal obesity was 1.00, 1.01 (0.94-1.07), 0.93 (0.87-0.99), and 0.89 (0.82-0.95), respectively. We found an interaction between altitude and sex and between altitude and age (P association with obesity and abdominal obesity. Among Peruvian adult individuals, we found an inverse association between altitude and obesity, adjusting for multiple covariates. This adjusted association varied by sex and age. © 2016 The Obesity Society.
Can people with Raynaud's phenomenon travel to high altitude?
Luks, Andrew M; Grissom, Colin K; Jean, Dominique; Swenson, Erik R
2009-01-01
To determine whether high altitude travel adversely affects mountain enthusiasts with Raynaud's phenomenon. Volunteers with Raynaud's phenomenon were recruited using announcements disseminated by organizations dedicated to climbing or wilderness travel and Internet discussion boards dedicated to mountain activities to complete an online, anonymous survey. Survey questions addressed demographic variables, aspects of their Raynaud's phenomenon, and features of their mountain activities. Respondents compared experiences with Raynaud's phenomenon between high (>2440 m; 8000 feet) and low elevations and rated agreement with statements concerning their disease and the effects of high altitude. One hundred forty-two people, 98% of whom had primary Raynaud's phenomenon, completed the questionnaire. Respondents spent 5 to 7 days per month at elevations above 2440 m and engaged in 5.4 +/- 2.0 different activities. Eighty-nine percent of respondents engaged in winter sports and only 22% reported changing their mountain activities because of Raynaud's phenomenon. Respondents reported a variety of tactics to prevent and treat Raynaud's attacks, but only 12% used prophylactic medications. Fifteen percent of respondents reported an episode of frostbite following a Raynaud's phenomenon attack at high altitude. There was considerable heterogeneity in participants' perceptions of the frequency, duration, and severity of attacks at high altitude compared to their home elevation. Motivated individuals with primary Raynaud's phenomenon, employing various prevention and treatment strategies, can engage in different activities, including winter sports, at altitudes above 2440 m. Frostbite may be common in this population at high altitude, and care must be taken to prevent its occurrence.
Polygenic Influence on Educational Attainment
Directory of Open Access Journals (Sweden)
Benjamin W. Domingue
2015-08-01
Full Text Available Recent studies have begun to uncover the genetic architecture of educational attainment. We build on this work using genome-wide data from siblings in the National Longitudinal Study of Adolescent to Adult Health (Add Health. We measure the genetic predisposition of siblings to educational attainment using polygenic scores. We then test how polygenic scores are related to social environments and educational outcomes. In Add Health, genetic predisposition to educational attainment is patterned across the social environment. Participants with higher polygenic scores were more likely to grow up in socially advantaged families. Even so, the previously published genetic associations appear to be causal. Among pairs of siblings, the sibling with the higher polygenic score typically went on to complete more years of schooling as compared to their lower-scored co-sibling. We found subtle differences between sibling fixed-effect estimates of the genetic effect versus those based on unrelated individuals.
The risk of cardiovascular events during leisure time activities at altitude.
Burtscher, Martin; Ponchia, Andrea
2010-01-01
Annually, more than 100 million tourists are attracted by the mountainous areas around the world. On the one hand, leisure time activities at altitude may well contribute to the well-established beneficial effects of exercise; on the other hand, these activities are also associated with a relatively high risk of death. Sudden cardiac death (SCD) is the most frequent cause of nontraumatic death in males older than 34 years at altitude during leisure time activities such as downhill skiing and hiking. Whereas prior myocardial infarction is the most important risk factor for SCD, particularly relevant in downhill skiers, the unusual physical activity during the first days at altitude and the prolonged abstinence from food and fluid intake during exercise at altitude are the most important triggers. Unaccustomed physical activity seems more likely to trigger SCD than altitude per se. The detection of subjects at risk, evidence-based therapy, and advice on adequate behavior during the altitude sojourn will help to prevent SCD and to increase the health benefits generated by mountaineering activities.
Rural-Nonrural Disparities in Postsecondary Educational Attainment Revisited
Byun, Soo-yong; Meece, Judith L.; Irvin, Matthew J.
2013-01-01
Using data from the National Educational Longitudinal Study, this study revisited rural-nonrural disparities in educational attainment by considering a comprehensive set of factors that constrain and support youth's college enrollment and degree completion. Results showed that rural students were more advantaged in community social resources compared to nonrural students, and these resources were associated with a significant increase in the likelihood of bachelor's degree attainment. Yet results confirmed that rural students lagged behind nonrural students in attaining a bachelor's degree largely due to their lower socioeconomic background. The findings present a more comprehensive picture of the complexity of geographic residence in shaping college enrollment and degree attainment. PMID:24285873
The FAA altitude chamber training flight profile : a survey of altitude reactions, 1965-1989.
1990-09-01
Reactions from 1,161 trainees out of 12,759 trainees subjected to the FAA altitude chamber training flights from 1965-1989 are annotated in this survey. Although there were some mild and expected reactions, these training profiles appear to provide a...
Autophagy Is a Promoter for Aerobic Exercise Performance during High Altitude Training
Directory of Open Access Journals (Sweden)
Ying Zhang
2018-01-01
Full Text Available High altitude training is one of the effective strategies for improving aerobic exercise performance at sea level via altitude acclimatization, thereby improving oxygen transport and/or utilization. But its underlying molecular mechanisms on physiological functions and exercise performance of athletes are still vague. More recent evidence suggests that the recycling of cellular components by autophagy is an important process of the body involved in the adaptive responses to exercise. Whether high altitude training can activate autophagy or whether high altitude training can improve exercise performance through exercise-induced autophagy is still unclear. In this narrative review article, we will summarize current research advances in the improvement of exercise performance through high altitude training and its reasonable molecular mechanisms associated with autophagy, which will provide a new field to explore the molecular mechanisms of adaptive response to high altitude training.
Phenotypic plasticity and genetic adaptation to high-altitude hypoxia in vertebrates.
Storz, Jay F; Scott, Graham R; Cheviron, Zachary A
2010-12-15
High-altitude environments provide ideal testing grounds for investigations of mechanism and process in physiological adaptation. In vertebrates, much of our understanding of the acclimatization response to high-altitude hypoxia derives from studies of animal species that are native to lowland environments. Such studies can indicate whether phenotypic plasticity will generally facilitate or impede adaptation to high altitude. Here, we review general mechanisms of physiological acclimatization and genetic adaptation to high-altitude hypoxia in birds and mammals. We evaluate whether the acclimatization response to environmental hypoxia can be regarded generally as a mechanism of adaptive phenotypic plasticity, or whether it might sometimes represent a misdirected response that acts as a hindrance to genetic adaptation. In cases in which the acclimatization response to hypoxia is maladaptive, selection will favor an attenuation of the induced phenotypic change. This can result in a form of cryptic adaptive evolution in which phenotypic similarity between high- and low-altitude populations is attributable to directional selection on genetically based trait variation that offsets environmentally induced changes. The blunted erythropoietic and pulmonary vasoconstriction responses to hypoxia in Tibetan humans and numerous high-altitude birds and mammals provide possible examples of this phenomenon. When lowland animals colonize high-altitude environments, adaptive phenotypic plasticity can mitigate the costs of selection, thereby enhancing prospects for population establishment and persistence. By contrast, maladaptive plasticity has the opposite effect. Thus, insights into the acclimatization response of lowland animals to high-altitude hypoxia can provide a basis for predicting how altitudinal range limits might shift in response to climate change.
Does Sibship Size Affect Educational Attainment?
DEFF Research Database (Denmark)
Jæger, Mads Meier
This paper implements a test of the Resource Dilution Hypothesis (RDH) stating that sibship size has a negative causal effect on educational attainment. Most existing studies using conventional methods support the RDH. This paper implements an Instrumental Variable (IV) approach to testing...... the claim of a negative causal relationship between sibship size and educational attainment. Analyzing data from the Wisconsin Longitudinal Study, the empirical analysis demonstrates, first, that conventional OLS regression estimates sibship size to have a negative effect on educational attainment equal...... to about one-tenth of a year of schooling per sibling. Second, when applying the IV method to account for potential endogeneity, the negative effect of sibship size increases substantially to about one-third of a year of schooling per sibling....
Chen, Yihang; Xiao, Chijie; Yang, Xiaoyi; Wang, Tianbo; Xu, Tianchao; Yu, Yi; Xu, Min; Wang, Long; Lin, Chen; Wang, Xiaogang
2017-10-01
The Laser-driven Ion beam trace probe (LITP) is a new diagnostic method for measuring poloidal magnetic field (Bp) and radial electric field (Er) in tokamaks. LITP injects a laser-driven ion beam into the tokamak, and Bp and Er profiles can be reconstructed using tomography methods. A reconstruction code has been developed to validate the LITP theory, and both 2D reconstruction of Bp and simultaneous reconstruction of Bp and Er have been attained. To reconstruct from experimental data with noise, Maximum Entropy and Gaussian-Bayesian tomography methods were applied and improved according to the characteristics of the LITP problem. With these improved methods, a reconstruction error level below 15% has been attained with a data noise level of 10%. These methods will be further tested and applied in the following LITP experiments. Supported by the ITER-CHINA program 2015GB120001, CHINA MOST under 2012YQ030142 and National Natural Science Foundation Abstract of China under 11575014 and 11375053.
Schobersberger, Wolfgang; Leichtfried, Veronika; Mueck-Weymann, Michael; Humpeler, Egon
2010-09-01
A considerable part of the millions of Alpine tourists suffer from pre-existing diseases (e.g., metabolic syndrome) and high daily stress levels. The main goal of the Austrian Moderate Altitude Study (AMAS) was to investigate (a) the consequences of an active vacation at moderate altitude on the key parameters of the metabolic syndrome (AMAS I) and (b) the effects of a short active vacation on adult progenitor cells, bio-psychological parameters, and heart rate variability (HRV). During the AMAS I pilot study (n = 22; 1,700 m a.s.l.) and AMAS I main study (n = 71; 1,700 m a.s.l. and 200 m a.s.l.), the volunteers simulated 3-week coached hiking vacations. For AMAS II, healthy volunteers (n = 13) participated in a 1-week active holiday at 1,700 m. There were significant improvements of obesity, hypertension, dyslipidemia, and insulin resistance of AMAS I patients after the vacation. In AMAS II participants, we found an increase in circulating endothelial progenitor cells as well as improvements in bio-psychological and HRV parameters. Active vacations at moderate altitude are associated with a variety of positive health effects in persons with metabolic syndrome and in healthy subjects.
Impact of Self-Regulatory Influences on Writing Course Attainment.
Zimmerman, Barry J.; Bandura, Albert
1994-01-01
Using path analysis, studied the role of self-efficacy beliefs concerning academic attainment and regulation of writing, academic goals, and self-standards in writing-course attainment of 95 college freshmen. Different facets of perceived self-efficacy played a key role in writing-course attainment. (SLD)
Fit for high altitude: are hypoxic challenge tests useful?
Directory of Open Access Journals (Sweden)
Matthys Heinrich
2011-02-01
Full Text Available Abstract Altitude travel results in acute variations of barometric pressure, which induce different degrees of hypoxia, changing the gas contents in body tissues and cavities. Non ventilated air containing cavities may induce barotraumas of the lung (pneumothorax, sinuses and middle ear, with pain, vertigo and hearing loss. Commercial air planes keep their cabin pressure at an equivalent altitude of about 2,500 m. This leads to an increased respiratory drive which may also result in symptoms of emotional hyperventilation. In patients with preexisting respiratory pathology due to lung, cardiovascular, pleural, thoracic neuromuscular or obesity-related diseases (i.e. obstructive sleep apnea an additional hypoxic stress may induce respiratory pump and/or heart failure. Clinical pre-altitude assessment must be disease-specific and it includes spirometry, pulsoximetry, ECG, pulmonary and systemic hypertension assessment. In patients with abnormal values we need, in addition, measurements of hemoglobin, pH, base excess, PaO2, and PaCO2 to evaluate whether O2- and CO2-transport is sufficient. Instead of the hypoxia altitude simulation test (HAST, which is not without danger for patients with respiratory insufficiency, we prefer primarily a hyperoxic challenge. The supplementation of normobaric O2 gives us information on the acute reversibility of the arterial hypoxemia and the reduction of ventilation and pulmonary hypertension, as well as about the efficiency of the additional O2-flow needed during altitude exposure. For difficult judgements the performance of the test in a hypobaric chamber with and without supplemental O2-breathing remains the gold standard. The increasing numbers of drugs to treat acute pulmonary hypertension due to altitude exposure (acetazolamide, dexamethasone, nifedipine, sildenafil or to other etiologies (anticoagulants, prostanoids, phosphodiesterase-5-inhibitors, endothelin receptor antagonists including mechanical aids to
Fit for high altitude: are hypoxic challenge tests useful?
Matthys, Heinrich
2011-02-28
Altitude travel results in acute variations of barometric pressure, which induce different degrees of hypoxia, changing the gas contents in body tissues and cavities. Non ventilated air containing cavities may induce barotraumas of the lung (pneumothorax), sinuses and middle ear, with pain, vertigo and hearing loss. Commercial air planes keep their cabin pressure at an equivalent altitude of about 2,500 m. This leads to an increased respiratory drive which may also result in symptoms of emotional hyperventilation. In patients with preexisting respiratory pathology due to lung, cardiovascular, pleural, thoracic neuromuscular or obesity-related diseases (i.e. obstructive sleep apnea) an additional hypoxic stress may induce respiratory pump and/or heart failure. Clinical pre-altitude assessment must be disease-specific and it includes spirometry, pulsoximetry, ECG, pulmonary and systemic hypertension assessment. In patients with abnormal values we need, in addition, measurements of hemoglobin, pH, base excess, PaO2, and PaCO2 to evaluate whether O2- and CO2-transport is sufficient.Instead of the hypoxia altitude simulation test (HAST), which is not without danger for patients with respiratory insufficiency, we prefer primarily a hyperoxic challenge. The supplementation of normobaric O2 gives us information on the acute reversibility of the arterial hypoxemia and the reduction of ventilation and pulmonary hypertension, as well as about the efficiency of the additional O2-flow needed during altitude exposure. For difficult judgements the performance of the test in a hypobaric chamber with and without supplemental O2-breathing remains the gold standard. The increasing numbers of drugs to treat acute pulmonary hypertension due to altitude exposure (acetazolamide, dexamethasone, nifedipine, sildenafil) or to other etiologies (anticoagulants, prostanoids, phosphodiesterase-5-inhibitors, endothelin receptor antagonists) including mechanical aids to reduce periodical or
Influence of the altitude on the burning velocity of the natural gas
International Nuclear Information System (INIS)
Arrieta, Andres Amell; Garcia Posada, Jorge Mario; Quilindo Valencia, Arvey; Henao Vallejo, Diego Alberto
2004-01-01
By the increasing use of natural gas in cities of Latin America located to high altitude, is necessary to study the effect of the altitude on the combustion, for example the burning velocity. This work is an experimental study of as it changes to the burning velocity with the altitude, being made test in sites with altitude of 40, 550, 1.020, 1.550, 2.040 and 2.550 meters. The result was that the variations are slight
Radiation exposure and high-altitude flight. NCRP Commentary No. 12
International Nuclear Information System (INIS)
1995-01-01
Enhanced air crew and public radiation exposure while flying at current altitudes and speeds has not been adequately addressed. However, the commercial aircraft industry continues to expand with greater numbers of passengers and more air crews year by year. With the expected expansions in high-altitude flight in the next two decades there will be many more people exposed to higher levels of ionizing radiation than currently. The equivalent dose rates at the higher altitudes are of the order of two to three times those received at current aircraft altitudes, but are not known very well, partly because of limitations in the knowledge of the component radiations, especially the high-energy neutron component. The risks are also more uncertain than for low-LET exposures on the ground because of uncertainty in an average W R to use for high-LET radiations. Exposures of current air crew are presently comparable with the average exposures of other radiation workers on the ground (EPA, 1995). Substantially higher exposures must be expected at high altitudes to air crew (perhaps approaching or possibly exceeding the current limit for workers on the ground). Higher exposures to sensitive groups of the population such as the fetuses carried by pregnant women are of special concern. Therefore, steps must be taken to improve our knowledge base with respect to dose levels and risks at these high altitudes. Following acquisition of this knowledge, modifications in radiation protection practices with respect to air crew and passengers will need to be considered and recommended to assure that adequate radiation protection is provided with respect to high-altitude flight
Iron Supplementation and Altitude: Decision Making Using a Regression Tree
Directory of Open Access Journals (Sweden)
Laura A. Garvican-Lewis, Andrew D. Govus, Peter Peeling, Chris R. Abbiss, Christopher J. Gore
2016-03-01
Full Text Available Altitude exposure increases the body’s need for iron (Gassmann and Muckenthaler, 2015, primarily to support accelerated erythropoiesis, yet clear supplementation guidelines do not exist. Athletes are typically recommended to ingest a daily oral iron supplement to facilitate altitude adaptations, and to help maintain iron balance. However, there is some debate as to whether athletes with otherwise healthy iron stores should be supplemented, due in part to concerns of iron overload. Excess iron in vital organs is associated with an increased risk of a number of conditions including cancer, liver disease and heart failure. Therefore clear guidelines are warranted and athletes should be discouraged from ‘self-prescribing” supplementation without medical advice. In the absence of prospective-controlled studies, decision tree analysis can be used to describe a data set, with the resultant regression tree serving as guide for clinical decision making. Here, we present a regression tree in the context of iron supplementation during altitude exposure, to examine the association between pre-altitude ferritin (Ferritin-Pre and the haemoglobin mass (Hbmass response, based on daily iron supplement dose. De-identified ferritin and Hbmass data from 178 athletes engaged in altitude training were extracted from the Australian Institute of Sport (AIS database. Altitude exposure was predominantly achieved via normobaric Live high: Train low (n = 147 at a simulated altitude of 3000 m for 2 to 4 weeks. The remaining athletes engaged in natural altitude training at venues ranging from 1350 to 2800 m for 3-4 weeks. Thus, the “hypoxic dose” ranged from ~890 km.h to ~1400 km.h. Ethical approval was granted by the AIS Human Ethics Committee, and athletes provided written informed consent. An in depth description and traditional analysis of the complete data set is presented elsewhere (Govus et al., 2015. Iron supplementation was prescribed by a sports physician
Genotype by environment interaction for growth due to altitude in United States Angus cattle.
Williams, J L; Bertrand, J K; Misztal, I; Łukaszewicz, M
2012-07-01
The objectives of this study were to determine if sires perform consistently across altitude and to quantify the genetic relationship between growth and survival at differing altitudes. Data from the American Angus Association included weaning weight (WW) adjusted to 205 (n = 77,771) and yearling weight adjusted to 365 (n = 39,450) d of age from 77,771 purebred Angus cattle born in Colorado between 1972 and 2007. Postweaning gain (PWG) was calculated by subtracting adjusted WW from adjusted yearling weight. Altitude was assigned to each record based upon the zip code of each herd in the database. Records for WW and PWG were each split into 2 traits measured at low and high altitude, with the records from medium altitude removed from the data due to inconsistencies between growth performance and apparent culling rate. A binary trait, survival (SV), was defined to account for censored records at yearling for each altitude. It was assumed that, at high altitude, individuals missing a yearling weight either died or required relocation to a lower altitude predominantly due to brisket disease, a condition common at high altitude. Model 1 considered each WW and PWG measured at 2 altitudes as separate traits. Model 2 treated PWG and SV measured as separate traits due to altitude. Models included the effects of weaning contemporary group, age of dam, animal additive genetic effects, and residual. Maternal genetic and maternal permanent environmental effects were included for WW. Heritability estimates for WW in Model 1 were 0.28 and 0.26 and for PWG were 0.26 and 0.19 with greater values in low altitude. Genetic correlations between growth traits measured at different altitude were moderate in magnitude: 0.74 for WW and 0.76 for PWG and indicate possibility of reranking of sires across altitude. Maternal genetic correlation between WW at varying altitude of 0.75 also indicates these may be different traits. In Model 2, heritabilities were 0.14 and 0.27 for PWG and 0.36 and
Mechanisms of Memory Dysfunction during High Altitude Hypoxia Training in Military Aircrew.
Nation, Daniel A; Bondi, Mark W; Gayles, Ellis; Delis, Dean C
2017-01-01
Cognitive dysfunction from high altitude exposure is a major cause of civilian and military air disasters. Pilot training improves recognition of the early symptoms of altitude exposure so that countermeasures may be taken before loss of consciousness. Little is known regarding the nature of cognitive impairments manifesting within this critical window when life-saving measures may still be taken. Prior studies evaluating cognition during high altitude simulation have predominantly focused on measures of reaction time and other basic attention or motor processes. Memory encoding, retention, and retrieval represent critical cognitive functions that may be vulnerable to acute hypoxic/ischemic events and could play a major role in survival of air emergencies, yet these processes have not been studied in the context of high altitude simulation training. In a series of experiments, military aircrew underwent neuropsychological testing before, during, and after brief (15 min) exposure to high altitude simulation (20,000 ft) in a pressure-controlled chamber. Acute exposure to high altitude simulation caused rapid impairment in learning and memory with relative preservation of basic visual and auditory attention. Memory dysfunction was predominantly characterized by deficiencies in memory encoding, as memory for information learned during high altitude exposure did not improve after washout at sea level. Retrieval and retention of memories learned shortly before altitude exposure were also impaired, suggesting further impairment in memory retention. Deficits in memory encoding and retention are rapidly induced upon exposure to high altitude, an effect that could impact life-saving situational awareness and response. (JINS, 2017, 23, 1-10).
The Gravity Field of Mercury After the Messenger Low-Altitude Campaign
Mazarico, Erwan; Genova, Antonio; Goossens, Sander; Lemoine, Frank G.; Smith, David E.; Zuber, Maria T.; Neumann, Gary A.; Solomon, Sean C.
2015-01-01
The final year of the MESSENGER mission was designed to take advantage of the remaining propellant onboard to provide a series of lowaltitude observation campaigns and acquire novel scientific data about the innermost planet. The lower periapsis altitude greatly enhances the sensitivity to the short-wavelength gravity field, but only when the spacecraft is in view of Earth. After more than 3 years in orbit around Mercury, the MESSENGER spacecraft was tracked for the first time below 200-km altitude on 5 May 2014 by the NASA Deep Space Network (DSN). Between August and October, periapsis passages down to 25-km altitude were routinely tracked. These periods considerably improved the quality of the data coverage. Before the end of its mission, MESSENGER will fly at very low altitudes for extended periods of time. Given the orbital geometry, however the periapses will not be visible from Earth and so no new tracking data will be available for altitudes lower than 75 km. Nevertheless, the continuous tracking of MESSENGER in the northern hemisphere will help improve the uniformity of the spatial coverage at altitudes lower than 150 km, which will further improve the overall quality of the Mercury gravity field.
Shape memory alloy resistance behaviour at high altitude for feedback control
Ng, W. T.; Sedan, M. F.; Abdullah, E. J.; Azrad, S.; Harithuddin, A. S. M.
2017-12-01
Many recent aerospace technologies are using smart actuators to reduce the system's complexity and increase its reliability. One such actuator is shape memory alloy (SMA) actuator, which is lightweight, produces high force and large deflection. However, some disadvantages in using SMA actuators have been identified and they include nonlinear response of the strain to input current, hysteresis characteristic that results in inaccurate control and less than optimum system performance, high operating temperatures, slow response and also high requirement of electrical power to obtain the desired actuation forces. It is still unknown if the SMA actuators can perform effectively at high altitude with low surrounding temperature. The work presented here covers the preliminary process of verifying the feasibility of using resistance as feedback control at high altitude for aerospace applications. Temperature and resistance of SMA actuator at high altitude is investigated by conducting an experiment onboard a high altitude balloon. The results from the high altitude experiment indicate that the resistance or voltage drop of the SMA wire is not significantly affected by the low surrounding temperature at high altitude as compared to the temperature of SMA. Resistance feedback control for SMA actuators may be suitable for aerospace applications.
Ocular morbidity among porters at high altitudes.
Gnyawali, Subodh; Shrestha, Gauri Shankar; Khanal, Safal; Dennis, Talisa; Spencer, John C
2017-01-01
High altitude, often characterized by settings over 2400m, can be detrimental to the human body and pose a significant risk to ocular health. Reports concerning various ocular morbidities occurring as a consequence of high altitude are limited in the current literature. This study was aimed at evaluating the ocular health of porters working at high altitudesof Himalayas in Nepal. A mobile eye clinic was set up in Ghat and patient data were collected from its out- patient unit by a team of seven optometrists which was run for five days. Ghat is a small village in north-eastern Nepal, located at 2860 m altitude. Travellers walking through the trekking route were invited to get their eyes checked at the clinic. Comprehensive ocular examinations were performed, including visual acuities, objective and subjective refraction, anterior and posterior segment evaluations, and intraocular pressure measurements; blood pressure and blood glucose levels were also measured as required. Ocular therapeutics, prescription glasses, sunglasses and ocular health referrals were provided free of cost as necessary. A total of 1890 people visited the eye clinic, among which 57.4% (n=1084) were porters. Almost half of the porters had an ocular morbidity. Correctable refractive error was most prevalent, with other ocular health-related complications, including dry eye disease, infectious disorders, glaucoma and cataract. Proper provision of regular and effective eye care services should be made more available for those residing at these high altitudes in Nepal. © NEPjOPH.
Influence of altitude training modality on performance and total haemoglobin mass in elite swimmers.
Gough, Clare E; Saunders, Philo U; Fowlie, John; Savage, Bernard; Pyne, David B; Anson, Judith M; Wachsmuth, Nadine; Prommer, Nicole; Gore, Christopher J
2012-09-01
We compared changes in performance and total haemoglobin mass (tHb) of elite swimmers in the weeks following either Classic or Live High:Train Low (LHTL) altitude training. Twenty-six elite swimmers (15 male, 11 female, 21.4 ± 2.7 years; mean ± SD) were divided into two groups for 3 weeks of either Classic or LHTL altitude training. Swimming performances over 100 or 200 m were assessed before altitude, then 1, 7, 14 and 28 days after returning to sea-level. Total haemoglobin mass was measured twice before altitude, then 1 and 14 days after return to sea-level. Changes in swimming performance in the first week after Classic and LHTL were compared against those of Race Control (n = 11), a group of elite swimmers who did not complete altitude training. In addition, a season-long comparison of swimming performance between altitude and non-altitude groups was undertaken to compare the progression of performances over the course of a competitive season. Regardless of altitude training modality, swimming performances were substantially slower 1 day (Classic 1.4 ± 1.3% and LHTL 1.6 ± 1.6%; mean ± 90% confidence limits) and 7 days (0.9 ± 1.0% and 1.9 ± 1.1%) after altitude compared to Race Control. In both groups, performances 14 and 28 days after altitude were not different from pre-altitude. The season-long comparison indicated that no clear advantage was obtained by swimmers who completed altitude training. Both Classic and LHTL elicited ~4% increases in tHb. Although altitude training induced erythropoeisis, this physiological adaptation did not transfer directly into improved competitive performance in elite swimmers.
Postsecondary Educational Attainment among Whites and Blacks.
Wolfle, Lee M.
Interracial differences in the educational attainment process between whites and blacks were examined, using Joreskog and Sorbom's (1981) general method for the analysis of covariance structures. The basic model of educational attainment considers education to be a function of father's occupational status and education, mother's education,…
Altitude training: an up-to-date approach and implementation in practice
Issurin, Vladimir
2007-01-01
This article overviews current comprehension of altitude training, which is quite contradictory: many sources declare that altitude training provides no benefits to sea level performances compared to appropriate conventional training while others consider altitude training to be an efficacious and proven tool to enhance high-performance preparation. This contradiction can be partly explained by the variety of individual training responses, i.e., individual predispositions among some athletes ...
Zhong, Rui; Liu, Hua; Wang, Hong; Li, Xiaojuan; He, Zeng; Gangla, Meiduo; Zhang, Jingdan; Han, Dingding; Liu, Jiaxin
2015-01-01
Hypoxia has been reported to cause the significant enhancement of hemoglobin (Hb) and hematocrit (Hct), which stabilizes at relatively high levels after an individual ascends to a high altitude. However, the quality of the suspended red blood cells (SRBCs) obtained from individuals at high altitudes such as Tibetan plateau migrants after storage has not been studied. In this study, we compared the storage quality of SRBCs prepared from Tibetan plateau and Deyang lowland populations by adding a normal volume of mannitol-adenine-phosphate (MAP), which is a common additive solution used in blood storage in Asian countries. The storage cell characteristics were examined on days 1, 7, 14 and 35.We found higher Hct and Hb levels and viscosity in the high altitude samples. The metabolic rates, including those for electrolytes and lactate, were higher in plateau SRBCs than in lowland SRBCs; these findings were consistent with the higher osmotic fragility and hemolysis of plateau SRBCs throughout the entire storage period. In addition, the reduction rates of 2,3-diphosphoglycerate (2,3-DPG) and oxygen tension to attain 50% oxygen saturation of Hb (P50) in plateau SRBCs were higher than those in lowland SRBCs, and the oxygen delivering capacity in plateau SRBCs was weaker than that in lowland SRBCs. We concluded that the storage quality of plateau SRBCs was inferior to that of lowland SRBCs when using the same concentration of MAP. We suggested that the optimal formula, including the MAP concentration or even a new additive solution, to store the plateau SRBCs must be assessed and regulated.
Wang, Hong; Li, Xiaojuan; He, Zeng; Gangla, Meiduo; Zhang, Jingdan; Han, Dingding; Liu, Jiaxin
2015-01-01
Hypoxia has been reported to cause the significant enhancement of hemoglobin (Hb) and hematocrit (Hct), which stabilizes at relatively high levels after an individual ascends to a high altitude. However, the quality of the suspended red blood cells (SRBCs) obtained from individuals at high altitudes such as Tibetan plateau migrants after storage has not been studied. In this study, we compared the storage quality of SRBCs prepared from Tibetan plateau and Deyang lowland populations by adding a normal volume of mannitol-adenine-phosphate (MAP), which is a common additive solution used in blood storage in Asian countries. The storage cell characteristics were examined on days1, 7, 14 and 35.We found higher Hct and Hb levels and viscosity in the high altitude samples. The metabolic rates, including those for electrolytes and lactate, were higher in plateau SRBCs than in lowland SRBCs; these findings were consistent with the higher osmotic fragility and hemolysis of plateau SRBCs throughout the entire storage period. In addition, the reduction rates of 2,3-diphosphoglycerate (2,3-DPG) and oxygen tension to attain 50% oxygen saturation of Hb (P50) in plateau SRBCs were higher than those in lowland SRBCs, and the oxygen delivering capacity in plateau SRBCs was weaker than that in lowland SRBCs. We concluded that the storage quality of plateau SRBCs was inferior to that of lowland SRBCs when using the same concentration of MAP. We suggested that the optimal formula, including the MAP concentration or even a new additive solution, to store the plateau SRBCs must be assessed and regulated. PMID:26637115
Directory of Open Access Journals (Sweden)
Rui Zhong
Full Text Available Hypoxia has been reported to cause the significant enhancement of hemoglobin (Hb and hematocrit (Hct, which stabilizes at relatively high levels after an individual ascends to a high altitude. However, the quality of the suspended red blood cells (SRBCs obtained from individuals at high altitudes such as Tibetan plateau migrants after storage has not been studied. In this study, we compared the storage quality of SRBCs prepared from Tibetan plateau and Deyang lowland populations by adding a normal volume of mannitol-adenine-phosphate (MAP, which is a common additive solution used in blood storage in Asian countries. The storage cell characteristics were examined on days 1, 7, 14 and 35.We found higher Hct and Hb levels and viscosity in the high altitude samples. The metabolic rates, including those for electrolytes and lactate, were higher in plateau SRBCs than in lowland SRBCs; these findings were consistent with the higher osmotic fragility and hemolysis of plateau SRBCs throughout the entire storage period. In addition, the reduction rates of 2,3-diphosphoglycerate (2,3-DPG and oxygen tension to attain 50% oxygen saturation of Hb (P50 in plateau SRBCs were higher than those in lowland SRBCs, and the oxygen delivering capacity in plateau SRBCs was weaker than that in lowland SRBCs. We concluded that the storage quality of plateau SRBCs was inferior to that of lowland SRBCs when using the same concentration of MAP. We suggested that the optimal formula, including the MAP concentration or even a new additive solution, to store the plateau SRBCs must be assessed and regulated.
Theoretical Evaluation of the Maximum Work of Free-Piston Engine Generators
Kojima, Shinji
2017-01-01
Utilizing the adjoint equations that originate from the calculus of variations, we have calculated the maximum thermal efficiency that is theoretically attainable by free-piston engine generators considering the work loss due to friction and Joule heat. Based on the adjoint equations with seven dimensionless parameters, the trajectory of the piston, the histories of the electric current, the work done, and the two kinds of losses have been derived in analytic forms. Using these we have conducted parametric studies for the optimized Otto and Brayton cycles. The smallness of the pressure ratio of the Brayton cycle makes the net work done negative even when the duration of heat addition is optimized to give the maximum amount of heat addition. For the Otto cycle, the net work done is positive, and both types of losses relative to the gross work done become smaller with the larger compression ratio. Another remarkable feature of the optimized Brayton cycle is that the piston trajectory of the heat addition/disposal process is expressed by the same equation as that of an adiabatic process. The maximum thermal efficiency of any combination of isochoric and isobaric heat addition/disposal processes, such as the Sabathe cycle, may be deduced by applying the methods described here.
Critical electric field for maximum tunability in nonlinear dielectrics
Akdogan, E. K.; Safari, A.
2006-09-01
The authors develop a self-consistent thermodynamic theory to compute the critical electric field at which maximum tunability is attained in a nonlinear dielectric. They then demonstrate that the stored electrostatic free energy functional has to be expanded at least up to the sixth order in electric field so as to define the critical field, and show that it depends solely on the fourth and sixth order permittivities. They discuss the deficiency of the engineering tunability metric in describing nonlinear dielectric phenomena, introduce a critical field renormalized tunability parameter, and substantiate the proposed formalism by computing the critical electric field for prototypical 0.9Pb(Mg1/3,Nb2/3)-0.1PbTiO3 and Ba(Ti0.85,Sn0.15)O3 paraelectrics.
Outdoor Activity and High Altitude Exposure During Pregnancy: A Survey of 459 Pregnancies.
Keyes, Linda E; Hackett, Peter H; Luks, Andrew M
2016-06-01
To evaluate whether women engage in outdoor activities and high altitude travel during pregnancy; the health care advice received regarding high altitude during pregnancy; and the association between high altitude exposure and self-reported pregnancy complications. An online survey of women with at least 1 pregnancy distributed on websites and e-mail lists targeting mothers and/or mountain activities. Outcome measures were outdoor activities during pregnancy, high altitude (>2440 m) exposure during pregnancy, and pregnancy and perinatal complications. Hiking, running, and swimming were the most common activities performed during pregnancy. Women traveled to high altitude in over half of the pregnancies (244/459), and most did not receive counseling regarding altitude (355, 77%), although a small proportion (14, 3%) were told not to go above 2440 m. Rates of miscarriage and most other complications were similar between pregnancies with and without travel above 2440 m. Pregnancies with high altitude exposure were more likely to have preterm labor (odds ratio [OR] 2.3; 95% CI 0.97-5.4; P = .05). Babies born to women who went to high altitude during pregnancy were more likely to need oxygen at birth (OR 2.34; 95% CI 1.04-5.26; P sports and travel to high altitude have a low rate of complications. Given the limitations of our data, further research is necessary on the risks associated with high altitude travel and physical activity and how these apply to the general population. Copyright © 2016 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.
International Nuclear Information System (INIS)
Sun Jingwen
1999-11-01
The author briefly introduces some knowledge about high altitude nuclear explosion (HANE) and presents a general review on high altitude nuclear tests of USA and former USSR. Physical phenomenon generated by HANE is given. The effects of HANE on space flyer, artificial satellite and communication are discussed. Some aspects of a mechanism of antimissile for HANE are described and the effect and role of HANE for USA and USSR are reviewed
Sequencing of 50 human exomes reveals adaptation to high altitude
DEFF Research Database (Denmark)
Yi, Xin; Liang, Yu; Huerta-Sanchez, Emilia
2010-01-01
Residents of the Tibetan Plateau show heritable adaptations to extreme altitude. We sequenced 50 exomes of ethnic Tibetans, encompassing coding sequences of 92% of human genes, with an average coverage of 18x per individual. Genes showing population-specific allele frequency changes, which repres...... in genetic adaptation to high altitude.......Residents of the Tibetan Plateau show heritable adaptations to extreme altitude. We sequenced 50 exomes of ethnic Tibetans, encompassing coding sequences of 92% of human genes, with an average coverage of 18x per individual. Genes showing population-specific allele frequency changes, which...... represent strong candidates for altitude adaptation, were identified. The strongest signal of natural selection came from endothelial Per-Arnt-Sim (PAS) domain protein 1 (EPAS1), a transcription factor involved in response to hypoxia. One single-nucleotide polymorphism (SNP) at EPAS1 shows a 78% frequency...
The radiation protection problems of high altitude and space flight
International Nuclear Information System (INIS)
Fry, R.J.M.
1993-01-01
This paper considers the radiation environment in aircraft at high altitudes and spacecraft in low earth orbit and in deep space and the factors that influence the dose equivalents. Altitude, latitude and solar cycle are the major influences for flights below the radiation belts. In deep space, solar cycle and the occurrence of solar particle events are the factors of influence. The major radiation effects of concern are cancer and infertility in males. In high altitude aircraft the radiation consists mainly of protons and neutrons, with neutrons contributing about half the equivalent dose. The average dose rate at altitudes of transcontinental flights that approach the polar regions are greater by a factor of about 2.5 than on routes at low latitudes. Current estimates of does to air crews suggest they are well within the ICRP (1990) recommended dose limits for radiation workers
[Cardiorespiratory capacity in children living at moderate altitude].
Gómez-Campos, Rossana; Arruda, Miguel; Almonacid-Fierro, Alejandro; Holbold, Edílson; Amaral-Camargo, Cristiane; Gamero, Diego; Cossio-Bolanos, Marco A
2014-04-01
To determine the cardiorespiratory capacity of school children living at moderate altitude. 795 children (394 children and 401 girls) were selected from urban public schools in Arequipa, Peru at moderate altitude (2,320 m). Anthropometric variables (body mass, height, body fat percentage) and cardiorespiratory capacity were assessed using the Course Navette test, considering the following categories: deficient, poor, fair, good, very good and excellent. The results showed significant differences in all categories (poverweight (r=-0.20 to -0.22) and a moderate negative correlation with obesity (r=-0.39 to -0.42) were described for both genders. Low levels of cardiorespiratory capacity in boys and girls living at moderate altitude are observed, which is negatively correlated with excess body weight. The results suggest that 1 in 5 children are likely to suffer some type of cardiovascular event.
Educational attainment, perceived control and the quality of women's diets.
Barker, Mary; Lawrence, Wendy; Crozier, Sarah; Robinson, Siân; Baird, Janis; Margetts, Barrie; Cooper, Cyrus
2009-06-01
Data from the Southampton Women's Survey have established that women of lower educational attainment have poorer quality diets than those of higher educational attainment. This relationship is strong and graded such that for every increase in level of educational qualification, there is an increase in the likelihood that a woman will have a better quality diet. It is not wholly explained by socio-economic status. Qualitative research carried out in Southampton suggests that women of lower educational attainment may have a poorer diet because they feel they lack control over the food choices they make for themselves and their families. We set out to investigate the relationship between educational attainment, perceived control and quality of diet in a sample of women from Southampton. Cross-sectional study using structured interviews in which women's diet, educational attainment and perceived control were assessed. 19 Children's Centres and baby clinics in Southampton, UK. 372 women, median age 28 years. Quality of diet assessed by prudent diet score produced from principal components analysis of 20-item food frequency questionnaire, and perceived control assessed by a validated questionnaire. Women of lower educational attainment tended to have lower prudent diet scores and lower perceived control scores than women of higher educational attainment. Having a lower prudent diet score was associated with consuming fewer vegetables and vegetable dishes, less wholemeal bread and vegetarian food, and more chips and roast potatoes, meat pies, Yorkshire puddings and pancakes, crisps and snacks, white bread and added sugar. In a regression model both lower educational attainment and lower perceived control were associated with lower prudent diet scores, independent of the effects of confounding factors. However there was an interaction effect such that lower perceived control was only related to prudent diet score in the group of women of lower educational attainment. Women
HIGH ALTITUDES EFFECTS ON HEMATOLOGIC BLOOD PARAMETERS
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Hasim Rushiti
2015-05-01
Full Text Available The approach and the objective of this experiment are consistent with the determination of changes of blood parameters after the stay of the students at an altitude of 1800-2300 meters, for a ten-day long ski course. In this paper are included a total of 64 students of the Faculty of Sport Sciences in Prishtina, of the age group of 19-25 (the average age is 21. All students previously have undergone a medical check for TA, arterial pulse and respiratory rate. In particular, the health situation is of subjects was examined, then, all students, at the same time, gave blood for analysis. In this experiment, three main hematologic parameters were taken in consideration: such as hemoglobin, hematocrit and red blood cells. The same analyses were carried out after the 10-day stay at a high altitude. The results of the experiment have shown significant changes after the ten-day stay at high altitude, despite the previous results that show changes only after the twenty-day stay in such elevations.
Genomic scan reveals loci under altitude adaptation in Tibetan and Dahe pigs.
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Kunzhe Dong
Full Text Available High altitude environments are of particular interest in the studies of local adaptation as well as their implications in physiology and clinical medicine in human. Some Chinese pig breeds, such as Tibetan pig (TBP that is well adapted to the high altitude and Dahe pig (DHP that dwells at the moderate altitude, provide ideal materials to study local adaptation to altitudes. Yet, it is still short of in-depth analysis and understanding of the genetic adaptation to high altitude in the two pig populations. In this study we conducted a genomic scan for selective sweeps using FST to identify genes showing evidence of local adaptations in TBP and DHP, with Wuzhishan pig (WZSP as the low-altitude reference. Totally, we identified 12 specific selective genes (CCBE1, F2RL1, AGGF1, ZFPM2, IL2, FGF5, PLA2G4A, ADAMTS9, NRBF2, JMJD1C, VEGFC and ADAM19 for TBP and six (OGG1, FOXM, FLT3, RTEL1, CRELD1 and RHOG for DHP. In addition, six selective genes (VPS13A, GNA14, GDAP1, PARP8, FGF10 and ADAMTS16 were shared by the two pig breeds. Among these selective genes, three (VEGFC, FGF10 and ADAMTS9 were previously reported to be linked to the local adaptation to high altitudes in pigs, while many others were newly identified by this study. Further bioinformatics analysis demonstrated that majority of these selective signatures have some biological functions relevant to the altitude adaptation, for examples, response to hypoxia, development of blood vessels, DNA repair and several hematological involvements. These results suggest that the local adaptation to high altitude environments is sophisticated, involving numerous genes and multiple biological processes, and the shared selective signatures by the two pig breeds may provide an effective avenue to identify the common adaptive mechanisms to different altitudes.
Monocular Vision System for Fixed Altitude Flight of Unmanned Aerial Vehicles
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Kuo-Lung Huang
2015-07-01
Full Text Available The fastest and most economical method of acquiring terrain images is aerial photography. The use of unmanned aerial vehicles (UAVs has been investigated for this task. However, UAVs present a range of challenges such as flight altitude maintenance. This paper reports a method that combines skyline detection with a stereo vision algorithm to enable the flight altitude of UAVs to be maintained. A monocular camera is mounted on the downside of the aircraft’s nose to collect continuous ground images, and the relative altitude is obtained via a stereo vision algorithm from the velocity of the UAV. Image detection is used to obtain terrain images, and to measure the relative altitude from the ground to the UAV. The UAV flight system can be set to fly at a fixed and relatively low altitude to obtain the same resolution of ground images. A forward-looking camera is mounted on the upside of the aircraft’s nose. In combination with the skyline detection algorithm, this helps the aircraft to maintain a stable flight pattern. Experimental results show that the proposed system enables UAVs to obtain terrain images at constant resolution, and to detect the relative altitude along the flight path.
The effects of classic altitude training on hemoglobin mass in swimmers.
Wachsmuth, N B; Völzke, C; Prommer, N; Schmidt-Trucksäss, A; Frese, F; Spahl, O; Eastwood, A; Stray-Gundersen, J; Schmidt, W
2013-05-01
Aim of the study was to determine the influence of classic altitude training on hemoglobin mass (Hb-mass) in elite swimmers under the following aspects: (1) normal oscillation of Hb-mass at sea level; (2) time course of adaptation and de-adaptation; (3) sex influences; (4) influences of illness and injury; (5) interaction of Hb-mass and competition performance. Hb-mass of 45 top swimmers (male 24; female 21) was repeatedly measured (~6 times) over the course of 2 years using the optimized CO-rebreathing method. Twenty-five athletes trained between one and three times for 3-4 weeks at altitude training camps (ATCs) at 2,320 m (3 ATCs) and 1,360 m (1 ATC). Performance was determined by analyzing 726 competitions according to the German point system. The variation of Hb-mass without hypoxic influence was 3.0 % (m) and 2.7 % (f). At altitude, Hb-mass increased by 7.2 ± 3.3 % (p altitude. In conclusion, the altitude (2,320 m) effect on Hb-mass is still present 3 weeks after return, it decisively depends on the health status, but is not influenced by sex. In healthy subjects it exceeds by far the oscillation occurring at sea level. After return from altitude performance increases after a delay of 3 weeks.
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Belén Feriche
Full Text Available When ascending to a higher altitude, changes in air density and oxygen levels affect the way in which explosive actions are executed. This study was designed to compare the effects of acute exposure to real or simulated moderate hypoxia on the dynamics of the force-velocity relationship observed in bench press exercise. Twenty-eight combat sports athletes were assigned to two groups and assessed on two separate occasions: G1 (n = 17 in conditions of normoxia (N1 and hypobaric hypoxia (HH and G2 (n = 11 in conditions of normoxia (N2 and normobaric hypoxia (NH. Individual and complete force-velocity relationships in bench press were determined on each assessment day. For each exercise repetition, we obtained the mean and peak velocity and power shown by the athletes. Maximum power (Pmax was recorded as the highest P(mean obtained across the complete force-velocity curve. Our findings indicate a significantly higher absolute load linked to P(max (∼ 3% and maximal strength (1 RM (∼ 6% in G1 attributable to the climb to altitude (P<0.05. We also observed a stimulating effect of natural hypoxia on P(mean and P(peak in the middle-high part of the curve (≥ 60 kg; P<0.01 and a 7.8% mean increase in barbell displacement velocity (P<0.001. No changes in any of the variables examined were observed in G2. According to these data, we can state that acute exposure to natural moderate altitude as opposed to simulated normobaric hypoxia leads to gains in 1 RM, movement velocity and power during the execution of a force-velocity curve in bench press.
Inequality and Educational Attainment: Evidence from Massachusetts
Papay, John P.; Murnane, Richard J.; Willett, John B.
2013-01-01
In the past thirty years educational attainments in the United States have stagnated, particularly for low-income Americans. As a result, income-related gaps in educational attainments have grown. These gaps are important because education has historically been the key mechanism for intergenerational socio-economic mobility in the U.S. While the…
High altitude medicine education in China: exploring a new medical education reform.
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.
Transcriptome and network changes in climbers at extreme altitudes.
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Fang Chen
Full Text Available Extreme altitude can induce a range of cellular and systemic responses. Although it is known that hypoxia underlies the major changes and that the physiological responses include hemodynamic changes and erythropoiesis, the molecular mechanisms and signaling pathways mediating such changes are largely unknown. To obtain a more complete picture of the transcriptional regulatory landscape and networks involved in extreme altitude response, we followed four climbers on an expedition up Mount Xixiabangma (8,012 m, and collected blood samples at four stages during the climb for mRNA and miRNA expression assays. By analyzing dynamic changes of gene networks in response to extreme altitudes, we uncovered a highly modular network with 7 modules of various functions that changed in response to extreme altitudes. The erythrocyte differentiation module is the most prominently up-regulated, reflecting increased erythrocyte differentiation from hematopoietic stem cells, probably at the expense of differentiation into other cell lineages. These changes are accompanied by coordinated down-regulation of general translation. Network topology and flow analyses also uncovered regulators known to modulate hypoxia responses and erythrocyte development, as well as unknown regulators, such as the OCT4 gene, an important regulator in stem cells and assumed to only function in stem cells. We predicted computationally and validated experimentally that increased OCT4 expression at extreme altitude can directly elevate the expression of hemoglobin genes. Our approach established a new framework for analyzing the transcriptional regulatory network from a very limited number of samples.
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Pflugrath, Brett D.; Brown, Richard S.; Carlson, Thomas J.
2012-03-01
This study investigated the maximum depth at which juvenile Chinook salmon Oncorhynchus tshawytscha can acclimate by attaining neutral buoyancy. Depth of neutral buoyancy is dependent upon the volume of gas within the swim bladder, which greatly influences the occurrence of injuries to fish passing through hydroturbines. We used two methods to obtain maximum swim bladder volumes that were transformed into depth estimations - the increased excess mass test (IEMT) and the swim bladder rupture test (SBRT). In the IEMT, weights were surgically added to the fishes exterior, requiring the fish to increase swim bladder volume in order to remain neutrally buoyant. SBRT entailed removing and artificially increasing swim bladder volume through decompression. From these tests, we estimate the maximum acclimation depth for juvenile Chinook salmon is a median of 6.7m (range = 4.6-11.6 m). These findings have important implications to survival estimates, studies using tags, hydropower operations, and survival of juvenile salmon that pass through large Kaplan turbines typical of those found within the Columbia and Snake River hydropower system.
Cerebral venous system and anatomical predisposition to high-altitude headache
Wilson, Mark H.; Davagnanam, Indran; Holland, Graeme; Dattani, Raj S.; Tamm, Alexander; Hirani, Shashivadan P.; Kolfschoten, Nicky; Strycharczuk, Lisa; Green, Cathy; Thornton, John S.; Wright, Alex; Edsell, Mark; Kitchen, Neil D.; Sharp, David J.; Ham, Timothy E.; Murray, Andrew; Holloway, Cameron J.; Clarke, Kieran; Grocott, Mike P. W.; Montgomery, Hugh; Imray, Chris; Ahuja, V.; Aref-Adib, G.; Burnham, R.; Chisholm, A.; Clarke, K.; Coates, D.; Coates, M.; Cook, D.; Cox, M.; Dhillon, S.; Dougall, C.; Doyle, P.; Duncan, P.; Edsell, M.; Edwards, L.; Evans, L.; Gardiner, P.; Grocott, M.; Gunning, P.; Hart, N.; Harrington, J.; Harvey, J.; Holloway, C.; Howard, D.; Hurlbut, D.; Imray, C.; Ince, C.; Jonas, M.; van der Kaaij, J.
2013-01-01
As inspired oxygen availability falls with ascent to altitude, some individuals develop high-altitude headache (HAH). We postulated that HAH results when hypoxia-associated increases in cerebral blood flow occur in the context of restricted venous drainage, and is worsened when cerebral compliance
Fatalities in high altitude mountaineering: a review of quantitative risk estimates.
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.
[Geographic Altitude of Residence and Alcohol Dependence in a Peruvian Population].
Quiñones-Laveriano, Dante Manuel; Espinoza-Chiong, César; Scarsi-Mejia, Ottavia; Rojas-Camayo, José; Mejia, Christian Richard
2016-01-01
The aim of this study was to determine the association between alcohol dependence and altitude of residence in 11 villages in two high altitude areas of Peru. An analytical cross-sectional study was performed using a survey conducted by physicians in primary health care in 11 villages until 2013, that were divided into low altitude (≤2500m asl (above sea level)), and high altitude (>2500m asl) areas. The CAGE test for alcoholism (cut point, ≥2) was applied to those who responded positively when asked if they consumed alcohol. Statistical associations were obtained with generalised linear models Of the 737 participants, 51% were women and the median age was 36 years [interquartile range, 25-50], 334 (45%) lived at low altitude, and 113 (15%) had alcohol dependence. The highest frequency of alcoholism was positively associated with being a village considered extremely poor (Likelihood Ratio (LP)=2.42; 95%CI, 1.40-4.19), while being female (LP=0.44; 95%CI, 0.23-0.89) and residing at high altitude (LP=0.15; 95%CI, 0.07-0.31) were negatively associated. These were adjusted for nine socio-occupational and pathological variables. According to these data, there is a higher frequency of alcohol dependence in being, male, extremely poor, and residing at low altitude. These results should be taken into account by professionals who work in primary care and those involved in mental health care, because of their implications in society. Copyright © 2015 Asociación Colombiana de Psiquiatría. Publicado por Elsevier España. All rights reserved.
Supplemental oxygen effect on hypoxemia at moderate altitude in patients with COPD.
Kelly, Paul T; Swanney, Maureen P; Stanton, Josh D; Frampton, Chris; Peters, Matthew J; Beckert, Lutz E
2009-09-01
Altitude exposure will cause moderate to severe hypoxemia in patients with chronic obstructive pulmonary disease (COPD). Supplemental oxygen can be used to attenuate this hypoxemia; however, individual response is variable and difficult to predict. The aim of this study was to assess the efficacy of oxygen supplementation in patients with COPD at a barometric pressure similar to that of a commercial aircraft cabin. Following sea-level (40 m) arterial blood gases measurements, 18 patients with COPD were driven to altitude (2086 m), where blood gases were repeated at rest and while on 2 L x min(-1) of supplementary oxygen (altitude O2). Ascent from sea level to altitude caused significant hypoxemia (75 +/- 9 vs. 51 +/- 6 mmHg), which was partially reversed by supplemental oxygen (64 +/- 9 mmHg). Oxygen supplementation did not significantly alter PaCO2 levels (vs. altitude PaCO2). There was a significant relationship between the sea-level CaO2 versus the altitude O2 CaO2 (r = 0.89, P commercial air travel in patients with COPD.
Groundwater arsenic and education attainment in Bangladesh.
Murray, Michael P; Sharmin, Raisa
2015-10-26
Thousands of groundwater tube wells serving millions of Bangladeshis are arsenic contaminated. This study investigates the effect of these wells on the education attainment and school attendance of youths who rely on those wells for drinking water. The analysis combines data from the 2006 Bangladesh Multiple Indicator Cluster Survey (2006 MICS) and the National Hydrochemical Survey (NHS) of Bangladeshi tube wells' contamination conducted between 1998 and 2000. The study uses multiple regression analysis to estimate the differences in education attainment and school attendance among the following: (i) youths who live where tube wells are safe, (ii) youths who live where tube wells are unsafe but who report drinking from an arsenic-free source, and (iii) youths who live where tube wells are unsafe but who do not report drinking from an arsenic-free source. Controlling for other determinants of education attainment and school attendance, young Bangladeshi males who live where tube wells are unsafe (by Bangladeshis standards) but who report drinking from arsenic-free sources are found to have the same education attainment (among 19- to 21-year-olds) and school attendance (among 6- to 10-year-olds), on average, as corresponding young Bangladeshi males who live where wells are safe. But young Bangladeshi males who live where tube wells are unsafe and who do not report drinking from an arsenic-free source attain, on average, a half-year less education (among 19- to 21-year-olds) and attend school, on average, five to seven fewer days a year (among 6- to 10-year-olds) than do other Bagladeshi males of those ages. The estimated effects for females are of the same sign but much smaller in magnitude. Bangladeshi public health measures to shift drinking from unsafe to safe wells not only advance good health but also increase males' education attainment.
High-altitude haematology: Quechua-Aymara comparisons.
Arnaud, J; Quilici, J C; Rivière, G
1981-01-01
Haematological studies have been carried out at various altitudes between 450 m and 4800 m, on two separate human groups (Quechuas and Aymaras) living in South America. Changes in the haematological parameters do not develop linearly in relation to the attitude. Th impact of chronic hypoxia on erythropoiesis is greater above 3000 m. The haemogram varies quantitatively and not qualitatively (mean corpuscular volume and mean haemoglobin concentration remain constant). The haematological study also reveals the greater adaptability to high altitude of the Aymaras, an adaptability characterized by an increase in red cell count and concentration and a decrease in red cell volume. The adaptative phenomena observed in the Quechuas are reversible, whereas they persist in the Aymaras when they migrate to the lowlands (450 m).
Cold induced peripheral vasodilation at high altitudes- a field study
Daanen, H.A.M.; Ruiten, H.J.A. van
2000-01-01
A significant reduction in cold-induced vasodilation (CIVD) is observed at high altitudes. No agreement is found in the literature about acclimatization effects on CIVD. Two studies were performed to investigate the effect of altitude acclimatization on CIVD. In the first study 13 male subjects
Altitude Performance Characteristics of Tail-pipe Burner with Variable-area Exhaust Nozzle
Jansen, Emmert T; Thorman, H Carl
1950-01-01
An investigation was conducted in the NACA Lewis altitude wind tunnel to determine effect of altitude and flight Mach number on performance of tail-pipe burner equipped with variable-area exhaust nozzle and installed on full-scale turbojet engine. At a given flight Mach number, with constant exhaust-gas and turbine-outlet temperatures, increasing altitude lowered the tail-pipe combustion efficiency and raised the specific fuel consumption while the augmented thrust ratio remained approximately constant. At a given altitude, increasing flight Mach number raised the combustion efficiency and augmented thrust ratio and lowered the specific fuel consumption.
Hematocrit and Hemoglobin Levels of Nonhuman Apes at Moderate Altitudes: A Comparison with Humans.
Mortola, Jacopo P; Wilfong, DeeAnn
2016-12-01
Mortola, Jacopo P. and DeeAnn Wilfong. Hematocrit and hemoglobin levels of nonhuman apes at moderate altitudes: a comparison with humans. High Alt Med Biol. 17:323-335, 2016.-We asked to what extent the hematologic response (increase in hematocrit [Hct] and in blood hemoglobin concentration [Hb]) of humans to altitude hypoxia was shared by our closest relatives, the nonhuman apes. Data were collected from 29 specimens of 7 species of apes at 2073 m altitude (barometric pressure Pb = 598 mm Hg); additional data originated from apes located at a lower altitude (1493 m, Pb = 639 mm Hg). The human altitude profiles of Hct and Hb between sea level and 3000 m were constructed from a compilation of literature sources that (all combined) comprised data sets of 10,000-12,000 subjects for each gender. These human data were binned for 0-250 m altitude (sea level) and for each 500 m of progressively higher altitudes. Values of Hb and Hct of both men and women were significantly higher than at sea level at the 1500 bin (1250-1750 m); hence, the altitude threshold for the human hematological responses must be between 1000 and 1500 m. In the nonhuman apes, no increase in Hct or Hb was apparent at 1500 m; at 2000 m, the increase was significant only for the Hb of females. At either altitude in the group of nonhuman apes, the increase in Hct was much less than in humans, and that of Hb was significantly less at 1500 m. We conclude that lack of, or minimal, hematopoietic response to moderate altitude can occur in mammalian species that are not genetically adapted to high altitudes. Polycythemia is not a common response to altitude hypoxia and, at least at moderate altitudes, the degree of the human response may represent the exception among apes rather than the rule.
Circulatory adaptation to long-term high altitude exposure in Aymaras and Caucasians.
Stuber, Thomas; Scherrer, Urs
2010-01-01
About 30 million people live above 2500 m in the Andean Mountains of South America. Among them are 5.5 million Aymaras, an ethnic group with its own language, living on the altiplano of Bolivia, Peru, and northern Chile at altitudes of up to 4400 m. In this high altitude region traces of human population go back for more than 2000 years with constant evolutionary pressure on its residents for genetic adaptation to high altitude. Aymaras as the assumed direct descendents of the ancient cultures living in this region were the focus of much research interest during the last decades and several distinctive adaptation patterns to life at high altitude have been described in this ethnic group. The aim of this article was to review the physiology and pathophysiology of circulatory adaptation and maladaptation to longtime altitude exposure in Aymaras and Caucasians.
Son, Hee Jeong; Kim, Hyo Jeong; Kim, Jin Hae; Ohno, Hideki; Kim, Chang Keun
2012-01-01
Rapid growth during adolescence caused by metabolic changes and their metabolic response to anaerobic and aerobic exercise differs considerably from that in adults and this is especially true in the responses to stresses, such as altitude exposure. However, there is little information on the suitability of exercise training at altitude for young athletes. Six male Korean adolescent alpine skiers (13-17 yr), with a skiing career of 3-5 yr, participated in the study. All subjects were exposed to an altitude of 2700 m (8858 ft) for 5 wk and altitude exposure consisted of 6 d/wk of training (4-5 h/d), with living quarters at 2100 m (-6890 ft) (Tignes, France). The 5 wk of ski training at altitude were maintained at the same level (the same number of slalom and giant slalom skiing trials) as at sea level. There was a significant increase in oxygen transport capacity, despite decreased erythropoietin (EPO) production (-31%) after altitude training. Red blood cell (RBC), hemoglobin (Hb), hematocrit (Hct), and 2,3 DPG concentrations increased significantly during altitude exposure and after return to sea level. Results indicate that applying altitude training in adolescent skiers may improve their endurance performance. However, EPO production during altitude training needs to be evaluated in larger future studies.
Increased insulin requirements during exercise at very high altitude in type 1 diabetes
de Mol, Pieter; de Vries, Suzanna T.; de Koning, Eelco J. P.; Gans, Rijk O. B.; Tack, Cees J.; Bilo, Henk J. G.
OBJECTIVE-Safe, very high altitude trekking in subjects with type 1 diabetes requires understanding of glucose regulation at high altitude. We investigated insulin requirements, energy expenditure, and glucose levels at very high altitude in relation to acute mountain sickness (AMS) symptoms in
Effect of high altitude cosmic irradiation upon cell generation time
International Nuclear Information System (INIS)
Soleilhavoup, J.P.; Croute, F.; Tixador, R.; Blanquet, Y.; Planel, H.
1975-01-01
Paramecia cultures placed at 3800 meter altitude show a proliferating activity acceleration compared to control cultures placed at low altitude under the same environment conditions. These results confirm the cosmic irradiation influence upon the activating effect produced by the natural ionizing radiations on living organisms [fr
Diurnal variations of serum erythropoietin at sea level and altitude
DEFF Research Database (Denmark)
Klausen, T; Poulsen, T D; Fogh-Andersen, N
1996-01-01
in 2, 3 diphosphoglycerate. After 64 h at altitude, six of the nine subjects had down-regulated their serum-EPO concentrations so that median values were three times above those at sea level. These six subjects had significant diurnal variations of serum-EPO concentration at sea level; the nadir......This study tested the hypothesis that the diurnal variations of serum-erythropoietin concentration (serum-EPO) observed in normoxia also exist in hypoxia. The study also attempted to investigate the regulation of EPO production during sustained hypoxia. Nine subjects were investigated at sea level...... and during 4 days at an altitude of 4350 m. Median sea level serum-EPO concentration was 6 (range 6-13) U.l-1. Serum-EPO concentration increased after 18 and 42 h at altitude, [58 (range 39-240) and 54 (range 36-340) U.l-1, respectively], and then decreased after 64 and 88 h at altitude [34 (range 18...
Altitude training for elite endurance athletes: A review for the travel medicine practitioner.
Flaherty, Gerard; O'Connor, Rory; Johnston, Niall
2016-01-01
High altitude training is regarded as an integral component of modern athletic preparation, especially for endurance sports such as middle and long distance running. It has rapidly achieved popularity among elite endurance athletes and their coaches. Increased hypoxic stress at altitude facilitates key physiological adaptations within the athlete, which in turn may lead to improvements in sea-level athletic performance. Despite much research in this area to date, the exact mechanisms which underlie such improvements remain to be fully elucidated. This review describes the current understanding of physiological adaptation to high altitude training and its implications for athletic performance. It also discusses the rationale and main effects of different training models currently employed to maximise performance. Athletes who travel to altitude for training purposes are at risk of suffering the detrimental effects of altitude. Altitude illness, weight loss, immune suppression and sleep disturbance may serve to limit athletic performance. This review provides an overview of potential problems which an athlete may experience at altitude, and offers specific training recommendations so that these detrimental effects are minimised. Copyright © 2016 Elsevier Ltd. All rights reserved.
Campbell, Aaron D; McIntosh, Scott E; Nyberg, Andy; Powell, Amy P; Schoene, Robert B; Hackett, Peter
2015-12-01
High-altitude athletes and adventurers face a number of environmental and medical risks. Clinicians often advise participants or guiding agencies before or during these experiences. Preparticipation evaluation (PPE) has the potential to reduce risk of high-altitude illnesses in athletes and adventurers. Specific conditions susceptible to high-altitude exacerbation also important to evaluate include cardiovascular and lung diseases. Recommendations by which to counsel individuals before participation in altitude sports and adventures are few and of limited focus. We reviewed the literature, collected expert opinion, and augmented principles of a traditional sport PPE to accommodate the high-altitude wilderness athlete/adventurer. We present our findings with specific recommendations on risk stratification during a PPE for the high-altitude athlete/adventurer. Copyright © 2015. Published by Elsevier Inc.
Space environment monitoring by low-altitude operational satellites
International Nuclear Information System (INIS)
Kroehl, H.W.
1982-01-01
The primary task of the Defense Meteorological Satellite Program (DMSP) is the acquisition of meteorological data in the visual and infrared spectral regions. The Air Weather Service operates two satellites in low-altitude, sun-synchronous, polar orbits at 850 km altitude, 98.7 deg inclination, 101.5 minute period and dawn-dusk or noon-midnight equatorial crossing times. Special DMSP sensors of interest to the space science community are the precipitating electron spectrometer, the terrestrial noise receiver, and the topside ionosphere plasma monitor. Data from low-altitude, meteorological satellites can be used to build empirical models of precipitating electron characteristics of the auroral zone and polar cap. The Tiros-NOAA satellite program complements the DMSP program. The orbital elements are the same as DMSP's, except for the times of equatorial crossing, and the tilt of the orbital plane. The Tiros-NOAA program meets the civilian community's needs for meteorological data as the DMSP program does for the military
Wilderness medicine at high altitude: recent developments in the field
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Shah NM
2015-09-01
Full Text Available Neeraj M Shah,1 Sidra Hussain,2 Mark Cooke,3 John P O’Hara,3 Adrian Mellor3,4 1Division of Asthma, Allergy and Lung Biology, King’s College London, UK; 2School of Medicine, University College London, London, UK; 3Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK; 4Academic Department of Military Anaesthesia and Critical Care, Royal Centre for Defence Medicine, Birmingham, UK Abstract: Travel to high altitude is increasingly popular. With this comes an increased incidence of high-altitude illness and therefore an increased need to improve our strategies to prevent and accurately diagnose these. In this review, we provide a summary of recent advances of relevance to practitioners who may be advising travelers to altitude. Although the Lake Louise Score is now widely used as a diagnostic tool for acute mountain sickness (AMS, increasing evidence questions the validity of doing so, and of considering AMS as a single condition. Biomarkers, such as brain natriuretic peptide, are likely correlating with pulmonary artery systolic pressure, thus potential markers of the development of altitude illness. Established drug treatments include acetazolamide, nifedipine, and dexamethasone. Drugs with a potential to reduce the risk of developing AMS include nitrate supplements, propagators of nitric oxide, and supplemental iron. The role of exercise in the development of altitude illness remains hotly debated, and it appears that the intensity of exercise is more important than the exercise itself. Finally, despite copious studies demonstrating the value of preacclimatization in reducing the risk of altitude illness and improving performance, an optimal protocol to preacclimatize an individual remains elusive. Keywords: hypoxia, acute mountain sickness, acclimatization, biomarkers, preacclimatization
Tropical temperature altitude amplification in the hiatus period (1998-2012
Directory of Open Access Journals (Sweden)
Ducić Vladan D.
2015-01-01
Full Text Available In the period 1998-2012 there was a stagnation in temperature rise, despite the GHGs radiation forcing is increased (hiatus period. According to Global Circulation Models simulations, expected response on the rise of GHGs forcing is tropical temperature altitude amplification - temperature increases faster in higher troposphere than in lower troposphere. In this paper, two satellite data sets, UAH MSU and RSS, were used to test altitude temperature amplification in tropic (20°N-20°S in the hiatus period. We compared data from satellite data sets from lower troposphere (TLT and middle troposphere (TMT in general and particularly for land and ocean (for UAH MSU. The results from both satellite measurements showed the presence of hiatus, i.e. slowdown of the temperature rise in the period 1998-2012 compared to period 1979-2012 (UAH MSU and temperature fall for RSS data. Smaller increase, i.e. temperature fall over ocean showed that hiatus is an ocean phenomenon above all. Data for UAH MSU showed that temperature altitude amplification in tropic was not present either for period 1979-2012, or 1998-2012. RSS data set also do not show temperature altitude amplification either for longer (1979-2012, or for shorter period (1998-2012. RSS data for successive 15-year periods from 1979-1993 till 1998-2012 does not show tropical temperature altitude amplification and in one case negative trend is registered in TLT and in two cases in TMT. In general, our results do not show presence of temperature altitude amplification in tropic in the hiatus period. [Projekat Ministarstva nauke Republike Srbije, br. III47007
Nutritional Strategies for the Preservation of Fat Free Mass at High Altitude
Directory of Open Access Journals (Sweden)
Stacie L. Wing-Gaia
2014-02-01
Full Text Available Exposure to extreme altitude presents many physiological challenges. In addition to impaired physical and cognitive function, energy imbalance invariably occurs resulting in weight loss and body composition changes. Weight loss, and in particular, loss of fat free mass, combined with the inherent risks associated with extreme environments presents potential performance, safety, and health risks for those working, recreating, or conducting military operations at extreme altitude. In this review, contributors to muscle wasting at altitude are highlighted with special emphasis on protein turnover. The article will conclude with nutritional strategies that may potentially attenuate loss of fat free mass during high altitude exposure.
Directory of Open Access Journals (Sweden)
He Chuan
2012-01-01
Full Text Available The cooperative scheduling problem on high-altitude airships for imaging observation tasks is discussed. A constraint programming model is established by analyzing the main constraints, which takes the maximum task benefit and the minimum cruising distance as two optimization objectives. The cooperative scheduling problem of high-altitude airships is converted into a main problem and a subproblem by adopting hierarchy architecture. The solution to the main problem can construct the preliminary matching between tasks and observation resource in order to reduce the search space of the original problem. Furthermore, the solution to the sub-problem can detect the key nodes that each airship needs to fly through in sequence, so as to get the cruising path. Firstly, the task set is divided by using k-core neighborhood growth cluster algorithm (K-NGCA. Then, a novel swarm intelligence algorithm named propagation algorithm (PA is combined with the key node search algorithm (KNSA to optimize the cruising path of each airship and determine the execution time interval of each task. Meanwhile, this paper also provides the realization approach of the above algorithm and especially makes a detailed introduction on the encoding rules, search models, and propagation mechanism of the PA. Finally, the application results and comparison analysis show the proposed models and algorithms are effective and feasible.
National Research Council Canada - National Science Library
Moore, Lorna
1998-01-01
.... Results indicated that the effects of the menstrual cycle were modest. In year 2, we evaluated the safety and efficacy of administering an a-adrenergic blocker and made selected observations during a brief exposure to an altitude of 4300 m...
High Altitude Clear Air Turbulence Project
National Oceanic and Atmospheric Administration, Department of Commerce — The Air Force Flight Dynamics Laboratory conducted the High Altitude Clear Air Turbulence Project in the mid 1960s with the intention of better understanding air...
Temporal and spatial changes in Western Himalayan firn line altitudes from 1998 to 2009
Guo, Zhongming; Wang, Ninglian; Kehrwald, Natalie M.; Mao, Ruijuan; Wu, Hongbo; Wu, Yuwei; Jiang, Xi
2014-07-01
Understanding changes in glacier mass balance is important because it is indicative of changes in climate and the hydrologic cycle. The latter also has particular influence on people living near glaciers and/or glacier-fed rivers. The Western Himalayas remain one of the regions where recent changes in glacier mass balance are not well-known. The temporal and spatial changes in firn line altitudes are an indicator of equilibrium line altitudes and thus reflect changes in glacier mass balance. Here, we use Himalayan Landsat TM/ETM + data in July and August (the late summer melt season) to quantify changes in firn line altitudes from 1998 to 2009. We produced reflectance maps through radiometric calibration and atmospheric correction and use topographic correction to remove or reduce terrain or shadow effects. The real ‘surface albedo’ is obtained by narrowband-to-broadband (NTB) albedo conversion from the combined solar radiation. The firn line altitude was then extracted by combining the ‘surface albedo’ with pre-registered digital elevation model. The individual firn line altitude varies by region. The Western Himalayas display the largest range of firn line variability, where the firn line altitudes vary from 4840 m a.s.l. to 5770 m a.s.l. The individual glacier mean firn line altitude from 1998 to 2009 rose from 5072 ± 77 m a.s.l. to 5640 ± 74 m a.s.l. in the Western Himalayas. The mean firn line altitude increased from 1998 to 2009. The lowest mean recorded firn line altitude recorded was 5237 ± 166 m a.s.l. in 1998, whereas the highest was 5397 ± 135 m a.s.l. in 2000. We also observed a difference between the changes in fine line altitudes of northern and southern slopes of the western Himalayans, as the northern slope glaciers display a greater increase in firn line altitudes than the southern slope glaciers. In the southern slope, changes in firn line altitudes correlate with NCDC-NOAA temperature and precipitation data. This sustained increase of
Effect of phosphate supplementation on oxygen delivery at high altitude
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.
[Relationship between baroreflex function and training effects on altitude training].
Yanagida, Ryo; Ogawa, Yojiro; Mizuochi, Fumio; Suzuki, Tsukasa; Takahashi, Masanori; Iwasaki, Kenichi
2012-05-01
Altitude training is frequently used for athletes requiring competitive endurance in an attempt to improve their sea-level performance. However, there has been no study in which the mechanisms by which spontaneous arterial-cardiac baroreflex function changes was examined in responders or nonresponders of altitude training. The purpose of this study was to clarify the different effects of altitude training on baroreflex function between responders and nonresponders. Twelve university student cross-country skiers (6 men, 6 women; age, 19±1 years) participated in the altitude training in a camp for 3 weeks, which was carried out in accordance with the method of Living High-Training Low. Baroreflex function was estimated by transfer function analysis before and after the training. The responders of the training were 3 men and 2 women, and the nonresponders were 3 men and 4 women. In the responders, the transfer function gain in the high-frequency range significantly increased after the training (28.9→46.5 ms/mmHg p=0.021). On the other hand, no significant change in this index was observed in the nonresponders (25.9→21.2 ms/mmHg p=0.405). As indicated by the results of transfer function gain in the high-frequency range, the baroreflex function in the responders increased significantly after the altitude training, whereas no significant change was observed in the nonresponders.
Adolescent obesity and future college degree attainment.
Fowler-Brown, Angela G; Ngo, Long H; Phillips, Russell S; Wee, Christina C
2010-06-01
The current impact of adolescent obesity on educational attainment is not clear. The objectives of our study were to determine whether adolescent obesity is associated with college degree attainment and how this association may have changed over time. We used data from a contemporary national cohort of over 4,000 persons who were adolescents (aged 14-18) in 1997 to assess the relationship between adolescent obesity and education. To assess for changes in this relationship over time, we also analyzed an older, similarly structured cohort of over 3,000 persons who were adolescents (aged 16-18) in 1981. Our primary outcome was college degree completion. We found that in the older cohort (adolescents in 1979), there were no differences in college degree attainment by adolescent weight status before and after adjustment. However, unadjusted analysis of the contemporary cohort (adolescents in 1997) demonstrated that those who were normal weight as adolescents had a higher prevalence of college degree attainment at follow-up compared to obese adolescents (24% vs. 10%). After adjustment for socio-demographic variables (age, sex, race, height, parental income-to-poverty ratio, parental education, aptitude test scores), obese adolescents were less likely to have attained a college degree compared to normal weight peers (adjusted risk ratio 0.61 95% confidence interval 0.38-0.83). Expectations for a future college degree did not vary by weight status and did not explain this observation. In conclusion, adolescent obesity is associated with lower likelihood of college completion. This relationship was not observed in an older cohort of adolescents.
Attaining high luminosity in linear e+e- colliders
International Nuclear Information System (INIS)
Palmer, R.B.
1990-11-01
The attainment of high luminosity in linear colliders is a complex problem because of the interdependence of the critical parameters. For instance, changing the number of particles per bunch affects the damping ring design and thus the emittance; it affects the wakefields in the linac and thus the momentum spread; the momentum spread affects the final focus design and thus the final β*; but the emittance change also affects the final focus design; and all these come together to determine the luminosity, disruption and beamstrahlung at the intersection. Changing the bunch length, or almost any other parameter, has a similar chain reaction. Dealing with this problem by simple scaling laws is very difficult because one does not know which parameter is going to be critical, and thus which should be held constant. One can only maximize the luminosity by a process of search and iteration. The process can be facilitated with the aid of a computer program. Examples can then be optimized for maximum luminosity, and compared to the optimized solutions with different approaches. This paper discusses these approaches
EFFECT OF HIGH ALTITUDE ON ERECTILE FUNCTION IN OTHERWISE HEALTHY INDIVIDUALS
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Usama Bin Zubair
2016-06-01
Full Text Available Objective: To determine the effect of high altitude on Erectile function in otherwise healthy individuals and associated socio demographic factors. Study Design: Cross sectional descriptive study. Place and Duration of Study: January 2014 to March 2014 at Goma, Siachin. Material and Methods: One hundred & twenty two married male subjects living at an altitude of more than 15000 feet for more than 3 month and less than one year were included in the study. Erectile dysfunction (ED was assessed using International Index of Erectile Function-5 (IIEF-5. Age, education, smoking, monthly income, any drug intake, altitude, duration of stay and weather conditions were correlated independently with ED. Results: Out of 122, 26 (21.3% had no ED, 18 had mild, 28 (14.8% had mild to moderate, 36(29.5% had moderate and 14 (11.5% had severe ED. Advancing age, low monthly income, smoking, high altitude, cold weather and longer duration of stay had significant association with ED (p-value<0.05 while education and use of any drug were not found significantly associated in our study. Conclusion: This study showed a high prevalence of erectile dysfunction among otherwise healthy individuals when exposed to high altitude. Special attention should be paid on individuals with more age, less income and those working or residing at higher altitudes in peak winter season. Smoking and stay for longer durations should also be discouraged.
The performance of Dräger Oxylog ventilators at simulated altitude.
Flynn, J G; Singh, B
2008-07-01
Ventilated patients frequently require transport by air in a hypobaric environment. Previous studies have demonstrated significant changes in the performance of ventilators with changes in cabin pressure (altitude) but no studies have been published on the function of modem ventilators at altitude. This experiment set out to evaluate ventilatory parameters (tidal volume and respiratory rate) of three commonly used transport ventilators (the Dräger Oxylog 1000, 2000 and 3000) in a simulated hypobaric environment. Ventilators were assessed using either air-mix (60% oxygen) or 100% oxygen and tested against models simulating a normal lung, a low compliance (Acute Respiratory Distress Syndrome) lung and a high-resistance (asthma) lung. Ventilators were tested at a range of simulated altitudes between sea level and 3048 m. Over this range, tidal volume delivered by the Oxylog 1000 increased by 68% and respiratory rate decreased by 28%. Tidal volume delivered by the Oxylog 2000 ventilator increased by 29% over the same range of altitudes but there was no significant change in respiratory rate. Tidal volume and respiratory rate remained constant with the Oxylog 3000 over the same range of altitudes. Changes were consistent with each ventilator regardless of oxygen content or lung model. It is important that clinicians involved in critical care transport in a hypobaric environment are aware that individual ventilators perform differently at altitude and that they are aware of the characteristics of the particular ventilator that they are using.
No Change in Running Mechanics With Live High-Train Low Altitude Training in Elite Distance Runners.
Stickford, Abigail S L; Wilhite, Daniel P; Chapman, Robert F
2017-01-01
Investigations into ventilatory, metabolic, and hematological changes with altitude training have been completed; however, there is a lack of research exploring potential gait-kinematic changes after altitude training, despite a common complaint of athletes being a lack of leg "turnover" on return from altitude training. To determine if select kinematic variables changed in a group of elite distance runners after 4 wk of altitude training. Six elite male distance runners completed a 28-d altitude-training intervention in Flagstaff, AZ (2150 m), following a modified "live high-train low" model, wherein higherintensity runs were performed at lower altitudes (945-1150 m) and low-intensity sessions were completed at higher altitudes (1950-2850 m). Gait parameters were measured 2-9 d before departure to altitude and 1 to 2 d after returning to sea level at running speeds of 300-360 m/min. No differences were found in ground-contact time, swing time, or stride length or frequency after altitude training (P > .05). Running mechanics are not affected by chronic altitude training in elite distance runners. The data suggest that either chronic training at altitude truly has no effect on running mechanics or completing the live high-train low model of altitude training, where higher-velocity workouts are completed at lower elevations, mitigates any negative mechanical adaptations that may be associated with chronic training at slower speeds.
Air to muscle O2 delivery during exercise at altitude
DEFF Research Database (Denmark)
Calbet, J.A.; Lundby, C.
2009-01-01
, diffusion limitation explains most of the additional Pao2-Pao2. With altitude, acclimatization exercise (Pao2-Pao2) is reduced, but does not reach the low values observed in high altitude natives, who possess an exceptionally high DLo2. Convective O2 transport depends on arterial O2 content (Cao2), cardiac...
Timing the arrival at 2340m altitude for aerobic performance
DEFF Research Database (Denmark)
Schuler, B; Thomsen, JJ; Gassmann, M
2007-01-01
This study tested the hypothesis that maximal oxygen uptake (VO2max) and performance increase upon altitude acclimatization at moderate altitude. Eight elite cyclists were studied at sea level, and after 1 (Day 1), 7 (Day 7), 14 (Day 14) and 21 (Day 21) days of exposure to 2340 m. Capillary blood...
Effects of Intermittent Altitude Exposures on Acclimatization of 4,300 M
National Research Council Canada - National Science Library
Beidleman, Beth
2001-01-01
This study examined the effects of 3 wk of intermittent exposures (4 h/d, 5 d/wk) to 4,300 m altitude-equivalent, in combination with either passive sitting or exercise training, on the process of altitude acclimatization...
Air Quality Standards for Particulate Matter (PM) at high altitude cities
International Nuclear Information System (INIS)
Bravo Alvarez, H.; Sosa Echeverria, R.; Sanchez Alvarez, P.; Krupa, S.
2013-01-01
The Air Quality Standards for Particulate Matter (PM) at high altitude urban areas in different countries, must consider the pressure and temperature due to the effect that these parameters have on the breath volume. This paper shows the importance to correct Air Quality Standards for PM considering pressure and temperature at different altitudes. Specific factors were suggested to convert the information concerning PM, from local to standard conditions, and adjust the Air Quality Standards for different high altitudes cities. The correction factors ranged from: 1.03 for Santiago de Chile to 1.47 for El Alto Bolivia. Other cities in this study include: Mexico City, México; La Paz, Bolivia; Bogota, Cali and Medellin, Colombia; Quito, Ecuador and Cuzco, Peru. If these corrections are not considered, the atmospheric concentrations will be underestimated. - Highlights: ► AQS for particulate matter concentrations adjusted by pressure and temperature. ► Particulate matter concentrations can be underestimated in high altitude Cities. ► Particulate matter concentrations must be compared under the same conditions. - In order to compare high altitude atmospheric PM concentrations with AQS, one must consider T and P of the sampling site.
Design study for remotely piloted, high-altitude airplanes powered by microwave energy
Morris, C. E. K., Jr.
1983-01-01
A design study has been conducted for unmanned, microwave-powered airplanes that must fly with long endurance at high altitude. They are proposed to conduct communications-relay, observation, or various scientific missions above approximately 55,000 feet altitude. The special characteristics of the microwave-power system and high-altitude, low-speed vehicle are reviewed. Examples of both sizing and performance analysis are used to suggest design procedure guidelines.
Nasal variation in relation to high-altitude adaptations among Tibetans and Andeans.
Butaric, Lauren N; Klocke, Ross P
2018-05-01
High-altitude (>2500 m) populations face several pressures, including hypoxia and cold-dry air, resulting in greater respiratory demand to obtain more oxygen and condition inspired air. While cardiovascular and pulmonary adaptations to high-altitude hypoxia have been extensively studied, adaptations of upper-respiratory structures, e.g., nasal cavity, remain untested. This study investigates whether nasal morphology presents adaptations to hypoxic (larger noses) and/or cold-dry (tall/narrow noses) conditions among high-altitude samples. CT scans of two high- and four low-altitude samples from diverse climates were collected (n = 130): high-altitude Tibetans and Peruvians; low-altitude Peruvians, Southern Chinese (temperate), Mongolian-Buriats (cold-dry), and Southeast Asians (hot-wet). Facial and nasal distances were calculated from 3D landmarks placed on digitally-modeled crania. Temperature, precipitation, and barometric pressure data were also obtained. Principal components analysis and analyses of variance primarily indicate size-related differences among the cold-dry (Mongolian-Buriats) and hot-wet (Southeast Asians) adapted groups. Two-block partial least squares (PLS) analysis show weak relationships between size-standardized nasal dimensions and environmental variables. However, among PLS1 (85.90% of covariance), Tibetans display relatively larger nasal cavities related to lower temperatures and barometric pressure; regression analyses also indicate high-altitude Tibetans possess relatively larger internal nasal breadths and heights for their facial size. Overall, nasal differences relate to climate among the cold-dry and hot-wet groups. Specific nasal adaptations were not identified among either Peruvian group, perhaps due to their relatively recent migration history and population structure. However, high-altitude Tibetans seem to exhibit a compromise in nasal morphology, serving in increased oxygen uptake, and air-conditioning processes. © 2018
Mapping local variation in educational attainment across Africa
Graetz, Nicholas; Friedman, Joseph; Osgood-Zimmerman, Aaron; Burstein, Roy; Biehl, Molly H.; Shields, Chloe; Mosser, Jonathan F.; Casey, Daniel C.; Deshpande, Aniruddha; Earl, Lucas; Reiner, Robert C.; Ray, Sarah E.; Fullman, Nancy; Levine, Aubrey J.; Stubbs, Rebecca W.; Mayala, Benjamin K.; Longbottom, Joshua; Browne, Annie J.; Bhatt, Samir; Weiss, Daniel J.; Gething, Peter W.; Mokdad, Ali H.; Lim, Stephen S.; Murray, Christopher J. L.; Gakidou, Emmanuela; Hay, Simon I.
2018-03-01
Educational attainment for women of reproductive age is linked to reduced child and maternal mortality, lower fertility and improved reproductive health. Comparable analyses of attainment exist only at the national level, potentially obscuring patterns in subnational inequality. Evidence suggests that wide disparities between urban and rural populations exist, raising questions about where the majority of progress towards the education targets of the Sustainable Development Goals is occurring in African countries. Here we explore within-country inequalities by predicting years of schooling across five by five kilometre grids, generating estimates of average educational attainment by age and sex at subnational levels. Despite marked progress in attainment from 2000 to 2015 across Africa, substantial differences persist between locations and sexes. These differences have widened in many countries, particularly across the Sahel. These high-resolution, comparable estimates improve the ability of decision-makers to plan the precisely targeted interventions that will be necessary to deliver progress during the era of the Sustainable Development Goals.
Indigenous Educational Attainment in Canada
Directory of Open Access Journals (Sweden)
Catherine E. Gordon
2014-06-01
Full Text Available In this article, the educational attainment of Indigenous peoples of working age (25 to 64 years in Canada is examined. This diverse population has typically had lower educational levels than the general population in Canada. Results indicate that, while on the positive side there are a greater number of highly educated Indigenous peoples, there is also a continuing gap between Indigenous and non-Indigenous peoples. Data also indicate that the proportion with less than high school education declined, which corresponds with a rise of those with a PSE; the reverse was true in 1996. Despite these gains, however, the large and increasing absolute numbers of those without a high school education is alarming. There are intra-Indigenous differences: First Nations with Indian Status and the Inuit are not doing as well as non-Status and Métis peoples. Comparisons between the Indigenous and non-Indigenous populations reveal that the documented gap in post-secondary educational attainment is at best stagnant. Out of the data analysis, and based on the history of educational policy, we comment on the current reform proposed by the Government of Canada, announced in February of 2014, and propose several policy recommendations to move educational attainment forward.
Zhu, Hai-tao; Bian, Chen; Yuan, Ji-chao; Liao, Xiao-jun; Liu, Wei; Zhu, Gang; Feng, Hua; Lin, Jiang-kai
2015-06-15
Intracerebral hemorrhage (ICH) at high altitude is not well understood to date. This study investigates the effects of high altitude on ICH, and examines the acute neuroprotection of hyperbaric oxygen (HBO) therapy against high-altitude ICH. Minipigs were placed in a hypobaric chamber for 72 h before the operation. ICH was induced by an infusion of autologous arterial blood (3 ml) into the right basal ganglia. Animals in the high-altitude ICH group received HBO therapy (2.5 ATA for 60 min) 30 min after ICH. Blood gas, blood glucose and brain tissue oxygen partial pressure (PbtO2) were monitored continuously for animals from all groups, as were microdialysis products including glucose, lactate, pyruvate and glutamate in perihematomal tissue from 3 to 12 h post-ICH. High-altitude ICH animals showed significantly lower PbtO2, higher lactate/pyruvate ratio (LPR) and glutamate levels than low-altitude ICH animals. More severe neurological deficits, brain edema and neuronal damage were also observed in high-altitude ICH. After HBO therapy, PbtO2 was significantly increased and LPR and glutamate levels were significantly decreased. Brain edema, neurological deficits and neuronal damage were also ameliorated. The data suggested a more serious disturbance of tissue oxygenation and cerebral metabolism in the acute stage after ICH at high altitude. Early HBO treatment reduced acute brain injury, perhaps through a mechanism involving the amelioration of the derangement of cerebral oxygenation and metabolism following high-altitude ICH.
Low-resolution ship detection from high-altitude aerial images
Qi, Shengxiang; Wu, Jianmin; Zhou, Qing; Kang, Minyang
2018-02-01
Ship detection from optical images taken by high-altitude aircrafts such as unmanned long-endurance airships and unmanned aerial vehicles has broad applications in marine fishery management, ship monitoring and vessel salvage. However, the major challenge is the limited capability of information processing on unmanned high-altitude platforms. Furthermore, in order to guarantee the wide detection range, unmanned aircrafts generally cruise at high altitudes, resulting in imagery with low-resolution targets and strong clutters suffered by heavy clouds. In this paper, we propose a low-resolution ship detection method to extract ships from these high-altitude optical images. Inspired by a recent research on visual saliency detection indicating that small salient signals could be well detected by a gradient enhancement operation combined with Gaussian smoothing, we propose the facet kernel filtering to rapidly suppress cluttered backgrounds and delineate candidate target regions from the sea surface. Then, the principal component analysis (PCA) is used to compute the orientation of the target axis, followed by a simplified histogram of oriented gradient (HOG) descriptor to characterize the ship shape property. Finally, support vector machine (SVM) is applied to discriminate real targets and false alarms. Experimental results show that the proposed method actually has high efficiency in low-resolution ship detection.
Interactions of carbon monoxide and hemoglobin at high altitude
Energy Technology Data Exchange (ETDEWEB)
Collier, C.R. (Univ. of Southern California Medical Center, Los Angeles); Goldsmith, J.R.
1983-01-01
The health risks to U.S. populations who are exposed to ambient carbon monoxide and live at altitudes (such as Denver, Salt Lake City, and Albuquerque) were evaluated using a set of mathematical models. The assumption that a given increase in carboxyhemoglobin would require a more stringent volumetric air quality standard was tested. The results using the model predict that the 8-h or 1-h standards adopted for sea level condition need not be altered to protect individuals against health risks at altitude, if the standards are in volumetric terms. They would need to be reduced if the standards are left in gravimetric terms. If the guideline is to be based on a given decrement of oxygen tension, many other variables must be specified, but expected differences in ambient carbon monoxide have a small impact compared to the effect of altitude itself.
Effects of repetitive training at low altitude on erythropoiesis in 400 and 800 m runners.
Frese, F; Friedmann-Bette, B
2010-06-01
Classical altitude training can cause an increase in total hemoglobin mass (THM) if a minimum "dose of hypoxia" is reached (altitude >or=2,000 m, >or=3 weeks). We wanted to find out if repetitive exposure to mild hypoxia during living and training at low altitude (training camps at low altitude interspersed by 3 weeks of sea-level training and at the same time points in a control group (CG) of 5 well-trained runners. EPO, sTfR and ferritin were also repeatedly measured during the altitude training camps. Repeated measures ANOVA revealed significant increases in EPO- and sTfR-levels during both training camps and a significant decrease in ferritin indicating enhanced erythropoietic stimulation during living and training at low altitude. Furthermore, significant augmentation of THM by 5.1% occurred in the course of the 2 altitude training camps. In conclusion, repetitive living and training at low altitude leads to a hypoxia-induced increase in erythropoietic stimulation in elite 400 m and 800 m runners and, apparently, might also cause a consecutive augmentation of THM.
TRENDS IN ESTIMATED MIXING DEPTH DAILY MAXIMUMS
Energy Technology Data Exchange (ETDEWEB)
Buckley, R; Amy DuPont, A; Robert Kurzeja, R; Matt Parker, M
2007-11-12
Mixing depth is an important quantity in the determination of air pollution concentrations. Fireweather forecasts depend strongly on estimates of the mixing depth as a means of determining the altitude and dilution (ventilation rates) of smoke plumes. The Savannah River United States Forest Service (USFS) routinely conducts prescribed fires at the Savannah River Site (SRS), a heavily wooded Department of Energy (DOE) facility located in southwest South Carolina. For many years, the Savannah River National Laboratory (SRNL) has provided forecasts of weather conditions in support of the fire program, including an estimated mixing depth using potential temperature and turbulence change with height at a given location. This paper examines trends in the average estimated mixing depth daily maximum at the SRS over an extended period of time (4.75 years) derived from numerical atmospheric simulations using two versions of the Regional Atmospheric Modeling System (RAMS). This allows for differences to be seen between the model versions, as well as trends on a multi-year time frame. In addition, comparisons of predicted mixing depth for individual days in which special balloon soundings were released are also discussed.
Directory of Open Access Journals (Sweden)
S. R. Verkulich
2013-01-01
Full Text Available The interstadial marine deposits stratum was described in the Fildes Peninsula (King George Island due to field and laboratory investigations during 2008–2011. The stratum fragments occur in the west and north-west parts of peninsula in following forms: sections of soft sediments, containing fossil shells, marine algae, bones of marine animals and rich marine diatom complexes in situ (11 sites; fragments of shells and bones on the surface (25 sites. According to the results of radiocarbon dating, these deposits were accumulated within the period 19–50 ky BP. Geographical and altitude settings of the sites, age characteristics, taxonomy of fossil flora and fauna, and good safety of the soft deposits stratum allow to make following conclusions: during interstadial, sea water covered significant part of King George Island up to the present altitude of 40 m a.s.l., and the King George Island glaciation had smaller size then; environmental conditions for the interstadial deposit stratum accumulation were at least not colder than today; probably, the King George island territory was covered entirely by ice masses of Last glacial maximum not earlier than 19 ky BP; during Last glacial maximum, King George Island was covered by thin, «cold», not mobile glaciers, which contribute to conservation of the soft marine interstadial deposits filled with fossil flora and fauna.
Observation of a 27-day solar signature in noctilucent cloud altitude
Köhnke, Merlin C.; von Savigny, Christian; Robert, Charles E.
2018-05-01
Previous studies have identified solar 27-day signatures in several parameters in the Mesosphere/Lower thermosphere region, including temperature and Noctilucent cloud (NLC) occurrence frequency. In this study we report on a solar 27-day signature in NLC altitude with peak-to-peak variations of about 400 m. We use SCIAMACHY limb-scatter observations from 2002 to 2012 to detect NLCs. The superposed epoch analysis method is applied to extract solar 27-day signatures. A 27-day signature in NLC altitude can be identified in both hemispheres in the SCIAMACHY dataset, but the signature is more pronounced in the northern hemisphere. The solar signature in NLC altitude is found to be in phase with solar activity and temperature for latitudes ≳ 70 ° N. We provide a qualitative explanation for the positive correlation between solar activity and NLC altitude based on published model simulations.
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.
A method for sampling microbial aerosols using high altitude balloons.
Bryan, N C; Stewart, M; Granger, D; Guzik, T G; Christner, B C
2014-12-01
Owing to the challenges posed to microbial aerosol sampling at high altitudes, very little is known about the abundance, diversity, and extent of microbial taxa in the Earth-atmosphere system. To directly address this knowledge gap, we designed, constructed, and tested a system that passively samples aerosols during ascent through the atmosphere while tethered to a helium-filled latex sounding balloon. The sampling payload is ~ 2.7 kg and comprised of an electronics box and three sampling chambers (one serving as a procedural control). Each chamber is sealed with retractable doors that can be commanded to open and close at designated altitudes. The payload is deployed together with radio beacons that transmit GPS coordinates (latitude, longitude and altitude) in real time for tracking and recovery. A cut mechanism separates the payload string from the balloon at any desired altitude, returning all equipment safely to the ground on a parachute. When the chambers are opened, aerosol sampling is performed using the Rotorod® collection method (40 rods per chamber), with each rod passing through 0.035 m3 per km of altitude sampled. Based on quality control measurements, the collection of ~ 100 cells rod(-1) provided a 3-sigma confidence level of detection. The payload system described can be mated with any type of balloon platform and provides a tool for characterizing the vertical distribution of microorganisms in the troposphere and stratosphere. Copyright © 2014 Elsevier B.V. All rights reserved.
A 45-year-old man with excessive daytime somnolence, and witnessed apnea at altitude
Directory of Open Access Journals (Sweden)
Welsh CH
2011-04-01
Full Text Available A sleepy man without sleep apnea at 1609m (5280 feet had disturbed sleep at his home altitude of 3200m (10500 feet. In addition to common disruptors of sleep such as psychophysiologic insomnia, restless leg syndrome, alcohol and excessive caffeine use, central sleep apnea with periodic breathing can be a significant cause of disturbed sleep at altitude. In symptomatic patients living at altitude, a sleep study at their home altitude should be considered to accurately diagnose the presence and magnitude of sleep disordered breathing as sleep studies performed at lower altitudes may miss this diagnosis. Treatments options differ from those to treat obstructive apnea. Supplemental oxygen is considered by many to be first-line therapy.
Update in the understanding of altitude-induced limitations to performance in team-sport athletes.
Billaut, François; Aughey, Robert J
2013-12-01
The internationalism of field-based team sports (TS) such as football and rugby requires teams to compete in tournaments held at low to moderate altitude (∼1200-2500 m). In TS, acceleration, speed and aerobic endurance are physical characteristics associated with ball possession and, ultimately, scoring. While these qualities are affected by the development of neuromuscular fatigue at sea level, arterial hypoxaemia induced by exposure to altitude may further hinder the capacity to perform consecutive accelerations (CAC) or sprint endurance and thereby change the outcome of a match. The higher the altitude, the more severe the hypoxaemia, and thus, the larger the expected decline in aerobic endurance, CAC and match running performance. Therefore, it is critical for athletes and coaches to understand how arterial hypoxaemia affects aerobic endurance and CAC and the magnitude of decline they may face at altitude for optimal preparation and increased chances of success. This mini review summarises the effects of acute altitude/hypoxia exposure on aerobic endurance, CAC and activity profiles of TS athletes performing in the laboratory and during matches at natural altitude, and analyses the latest findings about the consequences of arterial hypoxaemia on the relationship between peripheral perturbations, neural adjustments and performance during repeated sprints or CAC. Finally, we briefly discuss how altitude training can potentially help athletes prepare for competition at altitude.
Religious Background and Educational Attainment: The Effects of Buddhism, Islam, and Judaism
Sander, William
2010-01-01
The effects of Buddhism, Islam, and Judaism on educational attainment in the United States are examined. OLS estimates of educational attainment and Probit estimates of college attainment are undertaken. It is shown that Islam and Judaism have similar positive effects on attainment relative to Protestants and Catholics. The effect of Buddhism is…
Altitude training for elite endurance performance: a 2012 update.
Fudge, Barry W; Pringle, Jamie S M; Maxwell, Neil S; Turner, Gareth; Ingham, Stephen A; Jones, Andrew M
2012-01-01
Altitude training is commonly used by endurance athletes and coaches in pursuit of enhancement of performance on return to sea level. The purpose of the current review article was to update and evaluate recent literature relevant to the practical application of altitude training for endurance athletes. Consequently, the literature can be considered in either of two categories: performance-led investigations or mechanistic advancements/insights. Each section discusses the relevant literature and proposes future directions where appropriate.
Gore, Christopher J; Sharpe, Ken; Garvican-Lewis, Laura A; Saunders, Philo U; Humberstone, Clare E; Robertson, Eileen Y; Wachsmuth, Nadine B; Clark, Sally A; McLean, Blake D; Friedmann-Bette, Birgit; Neya, Mitsuo; Pottgiesser, Torben; Schumacher, Yorck O; Schmidt, Walter F
2013-12-01
To characterise the time course of changes in haemoglobin mass (Hbmass) in response to altitude exposure. This meta-analysis uses raw data from 17 studies that used carbon monoxide rebreathing to determine Hbmass prealtitude, during altitude and postaltitude. Seven studies were classic altitude training, eight were live high train low (LHTL) and two mixed classic and LHTL. Separate linear-mixed models were fitted to the data from the 17 studies and the resultant estimates of the effects of altitude used in a random effects meta-analysis to obtain an overall estimate of the effect of altitude, with separate analyses during altitude and postaltitude. In addition, within-subject differences from the prealtitude phase for altitude participant and all the data on control participants were used to estimate the analytical SD. The 'true' between-subject response to altitude was estimated from the within-subject differences on altitude participants, between the prealtitude and during-altitude phases, together with the estimated analytical SD. During-altitude Hbmass was estimated to increase by ∼1.1%/100 h for LHTL and classic altitude. Postaltitude Hbmass was estimated to be 3.3% higher than prealtitude values for up to 20 days. The within-subject SD was constant at ∼2% for up to 7 days between observations, indicative of analytical error. A 95% prediction interval for the 'true' response of an athlete exposed to 300 h of altitude was estimated to be 1.1-6%. Camps as short as 2 weeks of classic and LHTL altitude will quite likely increase Hbmass and most athletes can expect benefit.
Relationship of altitude mountain sickness and smoking: a Catalan traveller's cohort study.
Sánchez-Mascuñano, Alba; Masuet-Aumatell, Cristina; Morchón-Ramos, Sergio; Ramon, Josep M
2017-09-24
The aim of this study is to analyse the relationship between smoking and altitude mountain sickness in a cohort of travellers to 2500 metres above sea level (masl) or higher. Travel Health Clinic at the Hospital Universitari de Bellvitge, in Barcelona, Spain. A total of 302 adults seeking medical advice at the travel clinic, between July 2012 and August 2014, before travelling to 2500 masl or above, who agreed to participate in the study and to be contacted after the trip were included. Individuals who met the following criteria were excluded: younger than 18 years old, taking carbonic anhydrase inhibitors for chronic use, undergoing treatment with systemic corticosteroids and taking any medication that might prevent or treat altitude mountain sickness (AMS) prior to or during the trip. The majority of participants were women (n=156, 51.7%). The mean age was 37.7 years (SD 12.3). The studied cohort included 74 smokers (24.5%), 158 (52.3%) non-smokers and 70 (23.2%) ex-smokers. No statistical differences were observed between different sociodemographic characteristics, constitutional symptoms or drug use and smoking status. The main outcome was the development of AMS, which was defined according to the Lake Louise AMS criteria. AMS, according to the Lake Louise score, was significantly lower in smokers; the value was 14.9%, 95% CI (6.8 to 23.0%) in smokers and 29.4%, 95% CI (23.5 to 35.3%) in non-smokers with an adjusted OR of 0.54, 95% CI (0.31 to 0.97) independent of gender, age and maximum altitude reached. These results suggest that smoking could reduce the risk of AMS in non-acclimated individuals. Further studies should be performed in larger cohorts of travellers to confirm these results. Despite the results, smoking must be strongly discouraged because it greatly increases the risk of cardiorespiratory diseases, cancer and other diseases. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights
Hemoglobin mass after 21 days of conventional altitude training at 1816 m.
Pottgiesser, Torben; Ahlgrim, Christoph; Ruthardt, Sebastian; Dickhuth, Hans-Hermann; Schumacher, Yorck Olaf
2009-11-01
The underlying mechanisms of altitude training are still a matter of controversial discussion but erythropoietic adaptations with an increase of total haemoglobin mass (tHb) have been shown in several studies, partly depending on an adequate hypoxic dose. The aim of this retrospective study was to investigate if a 3 weeks sojourn at moderate altitude (1816 m) with conventional training sessions (live and train at moderate altitude), especially under real and uncontrolled conditions, results in an increased tHb. tHb was measured in seven male cyclists competing at elite level (German national cycling team, U23 category) prior to the ascent to altitude and immediately after descent to sea-level. The athletes completed a 21 days altitude training camp living at 1816 m and training at 1800-2400 m during the competitive season. No significant difference was found in tHb after the altitude sojourn (prior 927+/-109g vs. 951+/-113g post, 95% CI -13-61g). Additionally, the analysis of red cell volume, plasma volume and blood volume or haemoglobin concentration [Hb] as well as haematocrit (Hct) did not reveal any significant changes. The data supports the theory that an adequate hypoxic dose is required for adaptations of the erythropoietic system with an increase of tHb and a threshold of approximately 2100-2500 m has to be exceeded.
Yokoyama, T.; Ajith, K. K.; Yamamoto, M.; Niranjan, K.
2017-12-01
Equatorial plasma bubble (EPB) is a well-known phenomenon in the equatorial ionospheric F region. As it causes severe scintillation in the amplitude and phase of radio signals, it is important to understand and forecast the occurrence of EPBs from a space weather point of view. The development of EPBs is presently believed as an evolution of the generalized Rayleigh-Taylor instability. We have already developed a 3D high-resolution bubble (HIRB) model with a grid spacing of as small as 1 km and presented nonlinear growth of EPBs which shows very turbulent internal structures such as bifurcation and pinching. As EPBs have field-aligned structures, the latitude range that is affected by EPBs depends on the apex altitude of EPBs over the dip equator. However, it was not easy to observe the apex altitude and vertical rise velocity of EPBs. Equatorial Atmosphere Radar (EAR) in Indonesia is capable of steering radar beams quickly so that the growth phase of EPBs can be captured clearly. The vertical rise velocities of the EPBs observed around the midnight hours are significantly smaller compared to those observed in postsunset hours. Further, the vertical growth of the EPBs around midnight hours ceases at relatively lower altitudes, whereas the majority of EPBs at postsunset hours found to have grown beyond the maximum detectable altitude of the EAR. The HIRB model with varying background conditions are employed to investigate the possible factors that control the vertical rise velocity and maximum attainable altitudes of EPBs. The estimated rise velocities from EAR observations at both postsunset and midnight hours are, in general, consistent with the nonlinear evolution of EPBs from the HIRB model.
Mitochondrial function in human skeletal muscle following high-altitude exposure
DEFF Research Database (Denmark)
Jacobs, Robert A; Boushel, Robert; Wright-Paradis, Cynthia
2013-01-01
Studies regarding mitochondrial modifications in human skeletal muscle following acclimatization to high altitude are conflicting, and these inconsistencies may be due to the prevalence of representing mitochondrial function through static and isolated measurements of specific mitochondrial...... characteristics. The aim of this study, therefore, was to investigate mitochondrial function in response to high-altitude acclimatization through measurements of respiratory control in the vastus lateralis muscle. Skeletal muscle biopsies were obtained from 10 lowland natives prior to and again after a total of 9......-11 days of exposure to 4559 m. High-resolution respirometry was performed on the muscle samples to compare respiratory chain function and respiratory capacities. Respirometric analysis revealed that mitochondrial function was largely unaffected, because high-altitude exposure did not affect the capacity...
Directory of Open Access Journals (Sweden)
Chun Guo
2015-12-01
Full Text Available The low atmospheric pressure and low oxygen content in high-altitude environment have great impacts on the functions of human body. Especially for the personnel engaged in complicated physical labor such as tunnel construction, high altitude can cause a series of adverse physiological reactions, which may result in multiple high-altitude diseases and even death in severe cases. Artificial oxygen supply is required to ensure health and safety of construction personnel in hypoxic environments. However, there are no provisions for oxygen supply standard for tunnel construction personnel in high-altitude areas in current tunnel construction specifications. As a result, this paper has theoretically studied the impacts of high-altitude environment on human bodies, analyzed the relationship between labor intensity and oxygen consumption in high-altitude areas and determined the critical oxygen-supply altitude values for tunnel construction based on two different standard evaluation systems, i.e., variation of air density and equivalent PIO2. In addition, it has finally determined the oxygen supply standard for construction personnel in high-altitude areas based on the relationship between construction labor intensity and oxygen consumption.
Control of breathing and the circulation in high-altitude mammals and birds.
Ivy, Catherine M; Scott, Graham R
2015-08-01
Hypoxia is an unremitting stressor at high altitudes that places a premium on oxygen transport by the respiratory and cardiovascular systems. Phenotypic plasticity and genotypic adaptation at various steps in the O2 cascade could help offset the effects of hypoxia on cellular O2 supply in high-altitude natives. In this review, we will discuss the unique mechanisms by which ventilation, cardiac output, and blood flow are controlled in high-altitude mammals and birds. Acclimatization to high altitudes leads to some changes in respiratory and cardiovascular control that increase O2 transport in hypoxia (e.g., ventilatory acclimatization to hypoxia). However, acclimatization or development in hypoxia can also modify cardiorespiratory control in ways that are maladaptive for O2 transport. Hypoxia responses that arose as short-term solutions to O2 deprivation (e.g., peripheral vasoconstriction) or regional variation in O2 levels in the lungs (i.e., hypoxic pulmonary vasoconstriction) are detrimental at in chronic high-altitude hypoxia. Evolved changes in cardiorespiratory control have arisen in many high-altitude taxa, including increases in effective ventilation, attenuation of hypoxic pulmonary vasoconstriction, and changes in catecholamine sensitivity of the heart and systemic vasculature. Parallel evolution of some of these changes in independent highland lineages supports their adaptive significance. Much less is known about the genomic bases and potential interactive effects of adaptation, acclimatization, developmental plasticity, and trans-generational epigenetic transfer on cardiorespiratory control. Future work to understand these various influences on breathing and circulation in high-altitude natives will help elucidate how complex physiological systems can be pushed to their limits to maintain cellular function in hypoxia. Copyright © 2014 Elsevier Inc. All rights reserved.
Pituitary, gonadal and adrenal hormones after prolonged residence at extreme altitude in man.
Basu, M; Pal, K; Prasad, R; Malhotra, A S; Rao, K S; Sawhney, R C
1997-06-01
High altitude-induced alterations in pituitary, gonadal and adrenal hormones were studied in (i) eugonadal men from the armed forces who were resident at sea level (SL), (ii) SL residents staying at an altitude of 3542 m for periods ranging from 3 to 12 months (acclimatized lowlanders, ALL), (iii) ALL who stayed at 6300 m for 6 months, (iv) ALL who trekked from 3542 to 5080 m and stayed at an altitude of more than 6300 m in the glacier region for 6 months, and (v) high-altitude natives (HAN) resident at an altitude of 3300-3700 m. Circulating levels of LH, FSH, prolactin, cortisol, testosterone, dihydrotestosterone (DHT) and progesterone in ALL at 3542 m and in HAN were not significantly different (p > 0.05) from the SL control values. When the ALL living at 3542 m trekked to an extreme altitude of 5080 m, their testosterone levels showed a significant decrease (p 0.05) from the SL values. The LH levels after trekking to 5080 m were significantly higher (p 0.05) from the SL values. Plasma progesterone levels tended to increase on arrival at 5080 m but a significant increase (p < 0.001) was evident only after a 6-month stay at extreme altitude. These observations suggest that prolonged residence at lower as well as at extreme altitude does not appreciably alter blood levels of pituitary, gonadal or adrenal hormones except for plasma levels of progesterone. The exact mechanism and significance of this increase remains unknown, but may be important in increasing the sensitivity of the hypoxic ventilatory response and activation of haemoglobin synthesis.
Novel drugs in the management of acute mountain sickness and high altitude pulmonary edema
Directory of Open Access Journals (Sweden)
Sikri G
2015-12-01
Full Text Available Gaurav Sikri, Anirban Bhattacharya Department of Physiology, Armed Forces Medical College, Wanowarie, Pune, IndiaWe read with great interest the review article titled “Wilderness medicine at high altitude: recent developments in the field” by Shah et al.1 The authors have comprehensively summarized the recent advances in the field of high altitude medicine relevant to sports and travel medicine. However, Shah et al have described potential drugs for management of high-altitude illnesses, such as acute mountain sickness (AMS, high altitude cerebral edema, and high altitude pulmonary edema (HAPE as one group under the section “Novel drug treatment for AMS”. The pathophysiologies of these two sets of diseases (AMS/high altitude cerebral edema as one and HAPE as another set are different2 and hence it would have been nice to have had the novel drugs described separately to elucidate the therapeutic approach for the two different classes of diseases.View original paper by Shah et al.
Directory of Open Access Journals (Sweden)
Sheng Li Hu
Full Text Available Hypersensitive C-reaction protein (hsCRP may be a risk factor for cognitive impairment resulting from Alzheimer's disease (AD, stroke, and vascular dementia. This study explored the correlation of peripheral blood hsCRP level with cognitive decline due to high altitude exposure. The study was conducted on 100 male military participants who had never been to high altitude. Cerebral oxygen saturation monitoring, event related potentials (P300, N200 detection, and neurocognitive assessment was performed and total hsCRP, interleukin-6 (IL-6, and homocysteine was estimated at 500 m altitude, 3650 m altitude, 3 day, 1, and 3 month post arriving at the base camp (4400 m, and 1 month after coming back to the 500 m altitude. High altitude increased brain oxygen saturation, prolonged P300 and N200 latencies, injured cognitive functions, and raised plasma hsCRP levels. But they all recovered in varying degrees at 1 and 3 month post arriving at the base camp (4400 m. P300 latencies and hsCRP levels were strongly correlated to cognitive performances. These results suggested that cognitive deterioration occurred during the acute period of exposure to high altitude and may recover probably owning to acclimatization after extended stay at high altitude. Plasma hsCRP is inversely correlated to neurological cognition and it may be a potential biomarker for the prediction of high altitude induced cognitive dysfunction.
Turbojet Performance and Operation at High Altitudes with Hydrogen and Jp-4 Fuels
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.
Mast cells in the human lung at high altitude
Heath, Donald
1992-12-01
Mast cell densities in the lung were measured in five native highlanders of La Paz (3600 m) and in one lowlander dying from high-altitude pulmonary oedema (HAPO) at 3440 m. Two of the highlanders were mestizos with normal pulmonary arteries and the others were Aymara Indians with muscular remodelling of their pulmonary vasculature. The aim of the investigation was to determine if accumulation of mast cells in the lung at high altitude (HA) is related to alveolar hypoxia alone, to a combination of hypoxia and muscularization of the pulmonary arterial tree, or to oedema of the lung. The lungs of four lowlanders were used as normoxic controls. The results showed that the mast cell density of the two Mestizos was in the normal range of lowlanders (0.6-8.8 cells/mm2). In the Aymara Indians the mast cell counts were raised (25.6-26.0 cells/mm2). In the lowlander dying from HAPO the mast cell count was greatly raised to 70.1 cells/mm2 lung tissue. The results show that in native highlanders an accumulation of mast cells in the lung is not related to hypoxia alone but to a combination of hypoxia and muscular remodelling of the pulmonary arteries. However, the most potent cause of increased mast cell density in the lung at high altitude appears to be high-altitude pulmonary oedema.
Scientific Approach for Optimising Performance, Health and Safety in High-Altitude Observatories
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.
Unchanged cerebral blood flow and oxidative metabolism after acclimatization to high altitude
DEFF Research Database (Denmark)
Møller, Kirsten; Paulson, Olaf B; Hornbein, Thomas F.
2002-01-01
The authors investigated the effect of acclimatization to high altitude on cerebral blood flow and oxidative metabolism at rest and during exercise. Nine healthy, native sea-level residents were studied 3 weeks after arrival at Chacaltaya, Bolivia (5,260 m) and after reacclimatization to sea level....... At high altitude at rest, arterial carbon dioxide tension, oxygen saturation, and oxygen tension were significantly reduced, and arterial oxygen content was increased because of an increase in hemoglobin concentration. Global cerebral blood flow was similar in the four conditions. Cerebral oxygen delivery...... and cerebral metabolic rates of oxygen and glucose also remained unchanged, whereas cerebral metabolic rates of lactate increased slightly but nonsignificantly at high altitude during exercise compared with high altitude at rest. Reaction time was unchanged. The data indicate that cerebral blood flow...
A quantitative analysis of TIMS data obtained on the Learjet 23 at various altitudes
Jaggi, S.
1992-01-01
A series of Thermal Infrared Multispectral Scanner (TIMS) data acquisition flights were conducted on the NASA Learjet 23 at different altitudes over a test site. The objective was to monitor the performance of the TIMS (its estimation of the brightness temperatures of the ground scene) with increasing altitude. The results do not show any significant correlation between the brightness temperatures and the altitude. The analysis indicates that the estimation of the temperatures is a function of the accuracy of the atmospheric correction used for each altitude.
Elite and Status Attainment Models of Inequality of Opportunity
Myles, John F.; Srensen, Aage B.
1975-01-01
With changes in method, analysis of the process of attainment of various occupations and sub-sets of occupations such as elites can bring about the desired comparability between elite and status attainment studies of equality of opportunity. (Author/AM)
Fan, Jin-juan; Li, Dan-dan; Zhang, Xin-yu; He, Nian-peng; Bu, Jin-feng; Wang, Qing; Sun, Xiao-min; Wen, Xue-fa
2016-01-01
Soil samples, which were collected from three typical forests, i.e., Betula ermanii forest, coniferous mixed broad-leaved forest, and Pinus koraiensis forest, at different altitudes along the southern slope of Laotuding Mountain of Changbai Mountain range in Liaoning Province of China, were incubated over a temperature gradient in laboratory. Soil organic carbon mineralization rates (Cmin), soil β-1,4-glucosidase (βG) kinetics and their temperature sensitivity (Q₁₀) were measured. The results showed that both altitude and temperature had significant effects on Cmin · Cmin increased with temperature and was highest in the B. ermanii forest. The temperature sensitivity of Cmin [Q₁₀(Cmin)] ranked in order of B. ermanii forest > P. koraiensis forest > coniferous mixed broad-leaved forest, but did not differ significantly among the three forests. Both the maximum activity (Vmax) and the Michaelis constant (Km) of the βG responded positively to temperature for all the forests. The temperature sensitivity of Vmax [Q₁₀(Vmax)] ranged from 1.78 to 1.90, and the temperature sensitivity of Km [Q₁₀(Km)] ranged from 1.79 to 2.00. The Q₁₀(Vmax)/Q10(Km) ratios were significantly greater in the B. ermanii soil than in the other two forest soils, suggesting that the βG kinetics-dependent impacts of the global warming or temperature increase on the decomposition of soil organic carbon were temperature sensitive for the forests at the higher altitudes.
Constraints on food choices of women in the UK with lower educational attainment
DEFF Research Database (Denmark)
Barker, M.; Lawrence, W. T.; Skinner, T. C.
2008-01-01
Objective: Women of lower educational attainment have less balanced and varied diets than women of higher educational attainment. The diets of women are vital to the long-term health of their offspring. The present study aimed to identify factors that influence the food choices of women with lower...... educational attainment and how women could be helped to improve those choices. Design: We conducted eight focus group discussions with women of lower educational attainment to identify these factors. We contrasted the results of these discussions with those from three focus group discussions with women...... of higher educational attainment. Setting: Southampton, UK. Subjects: Forty-two white Caucasian women of lower educational attainment and fourteen of higher educational attainment aged 18 to 44 years. Results: The dominant theme in discussions with women of lower educational attainment was their sense...
Why women of lower educational attainment struggle to make healthier food choices
DEFF Research Database (Denmark)
Lawrence, Wendy; Skinner, Chas; Haslam, Cheryl
2009-01-01
Women of lower educational attainment are more likely to eat unhealthy diets than women of higher educational attainment. To identify influences on the food choices of women with lower educational attainment, 11 focus groups (eight with women of lower, and three with women of higher educational...... attainment) were held. Using a semi-structured discussion guide, environmental, social, historical and psychological factors known to be associated with food choice were explored. Audio recordings were transcribed verbatim and thematically analysed. Compared to women of higher educational attainment, women...... of lower educational attainment had less control over their families' food choices, less support for attempts to eat healthily, fewer opportunities to observe and learn good food-related practices, more negative affect, more perceived environmental constraints and more ambiguous beliefs about...
El-Jaby, Samy; Richardson, Richard B
2015-07-01
Occupational exposures from ionizing radiation are currently regulated for airline travel (Earth orbit (∼300-400 km). Aircrew typically receive between 1 and 6 mSv of occupational dose annually, while aboard the International Space Station, the area radiation dose equivalent measured over just 168 days was 106 mSv at solar minimum conditions. It is anticipated that space tourism vehicles will reach suborbital altitudes of approximately 100 km and, therefore, the annual occupational dose to flight crew during repeated transits is expected to fall somewhere between those observed for aircrew and astronauts. Unfortunately, measurements of the radiation environment at the high altitudes reached by suborbital vehicles are sparse, and modelling efforts have been similarly limited. In this paper, preliminary MCNPX radiation transport code simulations are developed of the secondary neutron flux profile in air from surface altitudes up to low Earth orbit at solar minimum conditions and excluding the effects of spacecraft shielding. These secondary neutrons are produced by galactic cosmic radiation interacting with Earth's atmosphere and are among the sources of radiation that can pose a health risk. Associated estimates of the operational neutron ambient dose equivalent, used for radiation protection purposes, and the neutron effective dose equivalent that is typically used for estimates of stochastic health risks, are provided in air. Simulations show that the neutron radiation dose rates received at suborbital altitudes are comparable to those experienced by aircrew flying at 7 to 14 km. We also show that the total neutron dose rate tails off beyond the Pfotzer maximum on ascension from surface up to low Earth orbit. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.
Maximal exercise and muscle oxygen extraction in acclimatizing lowlanders and high altitude natives
DEFF Research Database (Denmark)
Lundby, Carsten; Sander, Mikael; van Hall, Gerrit
2006-01-01
, and is the focus of the present study. We have studied six lowlanders during maximal exercise at sea level (SL) and with acute (AH) exposure to 4,100 m altitude, and again after 2 (W2) and 8 weeks (W8) of altitude sojourn, where also eight high altitude native (Nat) Aymaras were studied. Fractional arterial muscle...... O(2) extraction at maximal exercise was 90.0+/-1.0% in the Danish lowlanders at sea level, and remained close to this value in all situations. In contrast to this, fractional arterial O(2) extraction was 83.2+/-2.8% in the high altitude natives, and did not change with the induction of normoxia....... The capillary oxygen conductance of the lower extremity, a measure of oxygen diffusing capacity, was decreased in the Danish lowlanders after 8 weeks of acclimatization, but was still higher than the value obtained from the high altitude natives. The values were (in ml min(-1) mmHg(-1)) 55.2+/-3.7 (SL), 48...
Effect of egg composition and oxidoreductase on adaptation of Tibetan chicken to high altitude.
Jia, C L; He, L J; Li, P C; Liu, H Y; Wei, Z H
2016-07-01
Tibetan chickens have good adaptation to hypoxic conditions, which can be reflected by higher hatchability than lowland breeds when incubated at high altitude. The objective of this trial was to study changes in egg composition and metabolism with regards the adaptation of Tibetan chickens to high altitude. We measured the dry weight of chicken embryos, egg yolk, and egg albumen, and the activity of lactate dehydrogenase (LDH) and succinic dehydrogenase (SDH) in breast muscle, heart, and liver from embryos of Tibetan chicken and Dwarf chicken (lowland breed) incubated at high (2,900 m) and low (100 m) altitude. We found that growth of chicken embryos was restricted at high altitude, especially for Dwarf chicken embryos. In Tibetan chicken, the egg weight was lighter, but the dry weight of egg yolk was heavier than that of Dwarf chicken. The LDH activities of the three tissues from the high altitude groups were respectively higher than those of the lowland groups from d 15 to hatching, except for breast muscle of Tibetan chicken embryos on d 15. In addition, under the high altitude environment, the heart tissue from Tibetan chicken had lower LDH activity than that from Dwarf chicken at d 15 and 18. The lactic acid content of blood from Tibetan chicken embryos was lower than that of Dwarf chicken at d 12 and 15 of incubation at high altitude. There was no difference in SDH activity in the three tissues between the high altitude groups and the lowland groups except in three tissues of hatchlings and at d 15 of incubation in breast muscle, nor between the two breeds at high altitude except in the heart of hatchlings. Consequently, the adaptation of Tibetan chicken to high altitude may be associated with higher quantities of yolk in the egg and a low metabolic oxygen demand in tissue, which illuminate the reasons that the Tibetan chicken have higher hatchability with lower oxygen transport ability. © 2016 Poultry Science Association Inc.
Impact of a Newly Constructed Motor Vehicle Road on Altitude Illness in the Nepal Himalayas.
Reisman, Jonathan; Deonarain, Dinesh; Basnyat, Buddha
2017-12-01
This study investigated the impact that motor vehicle travel along a newly constructed road has on altitude illness (including acute mountain sickness, high-altitude cerebral edema, and high-altitude pulmonary edema). The new road from Besisahar (760 m) to Manang (3540 m) in Nepal was completed in December 2014. We enrolled all patients diagnosed with altitude illness at the Himalayan Rescue Association Manang clinic in fall 2016. Phi coefficients were calculated to test for an association between Nepali ethnicity and rapid ascent by motor vehicle. A retrospective review looked at all patients with altitude illness from fall (September-November) 2010 to spring (February-May) 2016. In fall 2016, more than half (54%) of patients with altitude illness traveled to Manang by motor vehicle, and one-third (33%) reached Manang from low altitude (Besisahar) in less than 48 hours. Nepali nationality had a significant association with motor vehicle travel (phi +0.69, P road (P constructed road from Besisahar to Manang appears to be related to a significant increase in the number of patients with all forms of altitude illness, especially among Nepalis. The authors believe that educational interventions emphasizing prevention are urgently needed. Copyright © 2017 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.
Riley, Callum James; Gavin, Matthew
2017-06-01
Riley, Callum James, and Matthew Gavin. Physiological changes to the cardiovascular system at high altitude and its effects on cardiovascular disease. High Alt Med Biol. 18:102-113, 2017.-The physiological changes to the cardiovascular system in response to the high altitude environment are well understood. More recently, we have begun to understand how these changes may affect and cause detriment to cardiovascular disease. In addition to this, the increasing availability of altitude simulation has dramatically improved our understanding of the physiology of high altitude. This has allowed further study on the effect of altitude in those with cardiovascular disease in a safe and controlled environment as well as in healthy individuals. Using a thorough PubMed search, this review aims to integrate recent advances in cardiovascular physiology at altitude with previous understanding, as well as its potential implications on cardiovascular disease. Altogether, it was found that the changes at altitude to cardiovascular physiology are profound enough to have a noteworthy effect on many forms of cardiovascular disease. While often asymptomatic, there is some risk in high altitude exposure for individuals with certain cardiovascular diseases. Although controlled research in patients with cardiovascular disease was largely lacking, meaning firm conclusions cannot be drawn, these risks should be a consideration to both the individual and their physician.
Text mining and network analysis to find functional associations of genes in high altitude diseases.
Bhasuran, Balu; Subramanian, Devika; Natarajan, Jeyakumar
2018-05-02
Travel to elevations above 2500 m is associated with the risk of developing one or more forms of acute altitude illness such as acute mountain sickness (AMS), high altitude cerebral edema (HACE) or high altitude pulmonary edema (HAPE). Our work aims to identify the functional association of genes involved in high altitude diseases. In this work we identified the gene networks responsible for high altitude diseases by using the principle of gene co-occurrence statistics from literature and network analysis. First, we mined the literature data from PubMed on high-altitude diseases, and extracted the co-occurring gene pairs. Next, based on their co-occurrence frequency, gene pairs were ranked. Finally, a gene association network was created using statistical measures to explore potential relationships. Network analysis results revealed that EPO, ACE, IL6 and TNF are the top five genes that were found to co-occur with 20 or more genes, while the association between EPAS1 and EGLN1 genes is strongly substantiated. The network constructed from this study proposes a large number of genes that work in-toto in high altitude conditions. Overall, the result provides a good reference for further study of the genetic relationships in high altitude diseases. Copyright © 2018 Elsevier Ltd. All rights reserved.
Butterflies of the high altitude Atacama Desert: habitat use and conservation
Directory of Open Access Journals (Sweden)
Emma eDespland
2014-09-01
Full Text Available The butterfly fauna of the high-altitude desert of Northern Chile, though depauperate, shows high endemism, is poorly known and is of considerable conservation concern. This study surveys butterflies along the Andean slope between 2400 and 500 m asl (prepuna, puna and Andean steppe habitats as well as in high and low altitude wetlands and in the neoriparian vegetation of agricultural sites. We also include historical sightings from museum records. We compare abundances between altitudes, between natural and impacted sites, as well as between two sampling years with different precipitation regimes. The results confirm high altitudinal turnover and show greatest similarity between wetland and slope faunas at similar altitudes. Results also underscore vulnerability to weather fluctuations, particularly in the more arid low-altitude sites, where abundances were much lower in the low precipitation sampling season and several species were not observed at all. Finally, we show that some species have shifted to the neoriparian vegetation of the agricultural landscape, whereas others were only observed in less impacted habitats dominated by native plants. These results suggest that acclimation to novel habitats depends on larval host plant use. The traditional agricultural environment can provide habitat for many, but not all, native butterfly species, but an estimation of the value of these habitats requires better understanding of butterfly life-history strategies and relationships with host plants.
Difference in blood microcirculation recovery between normal frostbite and high-altitude frostbite
Directory of Open Access Journals (Sweden)
Ming-ke JIAO
2017-02-01
Full Text Available Objective To determine the difference in blood microcirculation recovery between normal frostbite and high-altitude frostbite during the wound healing. Methods Twenty four male rats were randomly divided into control group (n=8, normal frostbite group (n=8, and high-altitude group (n=8. The normal frostbite group rats were frozen to produce mid-degree frostbite models by controlling the freezing time with liquid nitrogen penetration equipment. The high-altitude frostbite group rats were acclimated to a hypoxic and low-pressure environment for 1 week, and then the high-altitude frostbite models were constructed by the same way with liquid nitrogen penetration apparatus. On days 3, 7, 11, 15, 19, and 23 after modeling, the recovery situation of blood circulation of each group was observed with contrast ultrasonography by injecting SonoVue micro-bubble into rats' tail. Finally, the micro-bubble concentration (MC was calculated to confirm the blood circulation recovery with software Image Pro. Results At different time points, the wound area of the high-altitude frostbite group was bigger than that of the normal frostbite group, and the MC of control group was always about (27±0.2×109/ml. On day 3, 7, 11, 15, 19, and 23, the MC was significantly lower in the high-altitude frostbite group than in the control group and normal frostbite group (P<0.05. The MC of normal frostbite group was significantly lower than that of the control group on day 3, 7, 11, 15 and 19 (P<0.05. In addition, no obvious difference in MC was found between normal group and control group on the 23th day (P<0.05. Conclusion The blood microcirculation recovery after high-altitude frostbite is significantly slower than the normal frostbite. DOI: 10.11855/j.issn.0577-7402.2017.01.13
The structure of high altitude O+ energization and outflow: a case study
Directory of Open Access Journals (Sweden)
H. Nilsson
2004-07-01
Full Text Available Multi-spacecraft observations from the CIS ion spectrometers on board the Cluster spacecraft have been used to study the structure of high-altitude oxygen ion energization and outflow. A case study taken from 12 April 2004 is discussed in more detail. In this case the spacecraft crossed the polar cap, mantle and high-altitude cusp region at altitudes between 4RE and 8RE and 2 of the spacecraft provided data. The oxygen ions were seen as a beam with narrow energy distribution, and increasing field-aligned velocity and temperature at higher altitude further in the upstream flow direction. The peak O+ energy was typically just above the highest energy of observed protons. The observed energies reached the upper limit of the CIS ion spectrometer, i.e. 38keV. Moment data from the spacecraft have been cross-correlated to determine cross-correlation coefficients, as well as the phase delay between the spacecraft. Structures in ion density, temperature and field-aligned flow appear to drift with the observed field-perpendicular drift. This, together with a velocity dispersion analysis, indicates that much of the structure can be explained by transverse heating well below the spacecraft. However, temperature isotropy and the particle flux as a function of field-aligned velocity are inconsistent with a single altitude Maxwellian source. Heating over extended altitude intervals, possibly all the way up to the observation point, seem consistent with the observations.
High altitude-induced albuminuria in normal man is enhanced by infusion of low-dose dopamine
DEFF Research Database (Denmark)
Hansen, J M; Kanstrup, I L; Richalet, J P
1996-01-01
-85) (median with quartiles in parentheses) at high altitude. High altitude hypoxia increased Ualb from 3.2 micrograms min-1 (2.7-3.5) to 5.0 micrograms min-1 (3.3-6.6) (p ... flow (ERPF) from 465 ml min-1 (412-503) to 410 ml min-1 (385-451) (p high altitude. Dopamine...... increased ERPF, GFR, CLi, CNa, and decreased the filtration fraction in both environments. Infusion of dopamine further increased Ualb to 10.5 micrograms min-1 (5.5-64.8) (p high altitude, but had no effect on Ualb at sea level. In conclusion, high altitude hypoxia per se increases the urinary...
Adolescent Obesity and Future College Degree Attainment
Fowler-Brown, Angela G.; Ngo, Long H.; Phillips, Russell S.; Wee, Christina C.
2009-01-01
The current impact of adolescent obesity on educational attainment is not clear. The objectives of our study were to determine whether adolescent obesity is associated with college degree attainment and how this association may have changed over time. We used data from a contemporary national cohort of over 4,000 persons who were adolescents (aged 14–18) in 1997 to assess the relationship between adolescent obesity and education. To assess for changes in this relationship over time, we also a...
Negi, Prakash Chand; Marwaha, Rajeev; Asotra, Sanjeev; Kandoria, Arvind; Ganju, Neeraj; Sharma, Rajesh; Kumar, Ravi V; Bhardwaj, Rajeev
2014-12-01
The study aimed to determine the prevalence of high altitude pulmonary hypertension (HAPH) and its predisposing factors among natives of Spiti Valley. A cross-sectional survey study was done on the permanent natives of Spiti Valley residing at an altitude of 3000 m to 4200 m. Demographic characteristics, health behavior, anthropometrics, and blood pressure were recorded. Investigations included recording of 12 lead electrocardiogram (ECG), SaO2 with pulse oximeter, spirometry and echocardiography study, and measurement of Hb levels using the cynmethhemoglobin method. HAPH was diagnosed using criteria; tricuspid regurgitation (TR) gradient of ≥46 mmHg. ECG evidence of RV overload on 12 lead ECG was documented based on presence of 2 out of 3 criteria; R>S in V1, right axis deviation or RV strain, T wave inversion in V1 and V2. Data of 1087 subjects were analyzed who were free of cardiorespiratory diseases to determine the prevalence of HAPH and its predisposing factors. HAPH was recorded in 3.23% (95% C.I. of 0.9-8.1%) and ECG evidence of right ventricular (RV) overload was 1.5% in the study population. Prevalence of HAPH was not different in men and women 2.63% vs. 3.54% p<0.2. Age (Z statistics of 3.4 p<0.0006), hypoxemia (Z statistics of 2.9 p<0.002), and erythrocythemia (Z statistics of 4.7 p<0.003) were independently associated with HAPH. Altitude of residence was not found to be significantly associated with HAPH, although there was a trend of increasing prevalence with increasing altitude. It can be concluded that HAPH is prevalent in 3.23% of natives of Spiti Valley. Increasing age, erythrocythemia and hypoxemia are independent predisposing factors.
Carcass yields of two different strains of ducks raised in different altitude
Dillak, St. Y. F. G.; Mulyantini, N. G. A.; Sipahelut, G. M.; Lole, U. R.
2018-02-01
The objective of this research was to determine if there is a difference in performance and carcass yield between ducks of two different strains raised in different altitude. Ducks different strains (Muscovy vs Pekin ducks) and they raised either in high or low altitude (high altitude which was between 500 and 1000m vs low altitude which was below 500m). All ducks were given one of two different diet s and provided water ad libitum. The diets were: 1) commercial diet, and 2) local diet. There were three replicate per treatment and there were 5 ducks per replication. Ducks from each strain were standardized to a similar weight. The results show that Pekin ducks carcass performance was significantly better than Muscovy ducks. Ducks given diet 2 had significantly (Pabdominal fat percentage in Pekin ducks is significantly (Pabdominal fat percentage in Muscovy ducks.
Optic neuropathy following an altitude exposure.
Steigleman, Allan; Butler, Frank; Chhoeu, Austin; O'Malley, Timothy; Bower, Eric; Giebner, Stephen
2003-09-01
This case report describes a 20-yr-old man who presented with retro-orbital pain and blurred vision in his left eye 3 wk after an altitude exposure in a hypobaric chamber. He was found to have significant deficits in color vision and visual fields consistent with an optic neuropathy in his left eye. The patient was diagnosed with decompression sickness and treated with hyperbaric oxygen with a U.S. Navy Treatment Table VI. All signs and symptoms resolved with a single hyperbaric oxygen treatment but recurred. A head MRI revealed a left frontoethmoid sinus opacity. A concomitant sinusitis was diagnosed. The patient had full resolution of symptoms after a total of four hyperbaric oxygen treatments and antibiotic therapy at 6-wk follow-up. Although a para-infectious etiology for this patient's optic neuropathy cannot be excluded, his history of altitude exposure and significant, rapid response to hyperbaric oxygen treatment strongly implies decompression sickness in this case.
A Novel Approach to Critical Congenital Heart Disease (CCHD Screening at Moderate Altitude
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Erin Lueth
2016-07-01
Full Text Available The American Academy of Pediatrics (AAP has endorsed Critical Congenital Heart Disease (CCHD screening using pulse oximetry nationwide, but, however, acknowledges that altitude may impact failure rates and alternative algorithms may be required at high altitudes. We therefore evaluated a modified screening protocol at an altitude of 6200 feet with the hypothesis that modifications could decrease failure rates. We evaluated 2001 well, newborn infants ≥35 weeks gestation using a modified protocol, which included a lower saturation cutoff for the first screen (85% instead of the AAP recommended 90% and an oxygen hood intervention between the first two screens. Using our modified screening algorithm, we found a 0.3% failure rate, which was similar to the 0.2% sea-level rate and statistically different from the 1.1% rate identified in a recent study at similar altitude. Had the AAP protocol been used, the failure rate would have increased to 0.8%, which is similar to prior reports near this altitude. Echocardiograms were performed on failing newborns with no CCHD identified. A Birth Defects Registry Database review demonstrated one newborn with CCHD was missed after meeting AAP passing criteria. Overall, this study demonstrates that an alternative algorithm can be implemented at moderate altitude with decreased failure rate and comparable false negative rate.
The GRAD high-altitude balloon flight over Antarctica
International Nuclear Information System (INIS)
Eichhorn, G.; Coldwell, R.L.; Dunnam, F.E.; Rester, A.C.; Trombka, J.I.; Starr, R.; Lasche, G.P.
1989-01-01
The Gamma Ray Advanced Detector(GRAD) consists of a n-type germanium detector inside an active bismuth-germanate Compton and charged particle shield with additional active plastic shielding across the aperture. It will be flown on a high altitude balloon at 36 km altitude at a latitude of 78 degree S over Antarctica for observations of gamma radiation emitted by the radioactive decay of 56 Co in the Supernova SN1987A, for assessment of the performance of bismuth-germanate scintillation material in the radiation environment of near space, for gathering information on the gamma-ray background over Antarctica, and for testing fault-tolerant software
Vearrier, David; Greenberg, Michael I
2011-08-01
Mining operations conducted at high altitudes provide health challenges for workers as well as for medical personnel. To review the literature regarding adverse health effects and toxic exposures that may be associated with mining operations conducted at altitude and to discuss pre-placement screening, acclimatization issues, and on-site surveillance strategies. We used the Ovid ( http://ovidsp.tx.ovid.com ) search engine to conduct a MEDLINE search for "coal mining" or "mining" and "altitude sickness" or "altitude" and a second MEDLINE search for "occupational diseases" and "altitude sickness" or "altitude." The search identified 97 articles of which 76 were relevant. In addition, the references of these 76 articles were manually reviewed for relevant articles. CARDIOVASCULAR EFFECTS: High altitude is associated with increased sympathetic tone that may result in elevated blood pressure, particularly in workers with pre-existing hypertension. Workers with a history of coronary artery disease experience ischemia at lower work rates at high altitude, while those with a history of congestive heart failure have decreased exercise tolerance at high altitude as compared to healthy controls and are at higher risk of suffering an exacerbation of their heart failure. PULMONARY EFFECTS: High altitude is associated with various adverse pulmonary effects, including high-altitude pulmonary edema, pulmonary hypertension, subacute mountain sickness, and chronic mountain sickness. Mining at altitude has been reported to accelerate silicosis and other pneumoconioses. Miners with pre-existing pneumoconioses may experience an exacerbation of their condition at altitude. Persons traveling to high altitude have a higher incidence of Cheyne-Stokes respiration while sleeping than do persons native to high altitude. Obesity increases the risk of pulmonary hypertension, acute mountain sickness, and sleep-disordered breathing. NEUROLOGICAL EFFECTS: The most common adverse neurological
Calculating the Maximum Density of the Surface Packing of Ions in Ionic Liquids
Kislenko, S. A.; Moroz, Yu. O.; Karu, K.; Ivaništšev, V. B.; Fedorov, M. V.
2018-05-01
The maximum density of monolayer packing on a graphene surface is calculated by means of molecular dynamics (MD) for ions of characteristic size and symmetry: 1-butyl-3-methylimidazolium [BMIM]+, tetrabutylammonium [TBA]+, tetrafluoroborate [BF4]-, dicyanamide [DCA]-, and bis(trifluoromethane) sulfonimide [TFSI]-. The characteristic orientations of ions in a closely packed monolayer are found. It is shown that the formation of a closely packed monolayer is possible for [DCA]- and [BF4]- anions only at surface charges that exceed the limit of the electrochemical stability of the corresponding ionic liquids. For the [TBA]+ cation, a monolayer structure can be observed at the charge of nearly 30 μC/cm2 attainable in electrochemical experiment.
Acute Exposure of College Basketball Players to Moderate Altitude: Selected Physiological Responses.
Noble, Bruce J.; Maresh, Carl M.
1979-01-01
In general, basketball players with moderately high aerobic power who reside at an altitude of 1,000 m do not display the hypoxic response to an altitude of 2,200 m expected of sea level residents and aerobically trained athletes. (JD)
Proton isotropy boundaries as measured on mid- and low-altitude satellites
Directory of Open Access Journals (Sweden)
N. Yu. Ganushkina
2005-07-01
Full Text Available Polar CAMMICE MICS proton pitch angle distributions with energies of 31-80 keV were analyzed to determine the locations where anisotropic pitch angle distributions (perpendicular flux dominating change to isotropic distributions. We compared the positions of these mid-altitude isotropic distribution boundaries (IDB for different activity conditions with low-altitude isotropic boundaries (IB observed by NOAA 12. Although the obtained statistical properties of IDBs were quite similar to those of IBs, a small difference in latitudes, most pronounced on the nightside and dayside, was found. We selected several events during which simultaneous observations in the same local time sector were available from Polar at mid-altitudes, and NOAA or DMSP at low-altitudes. Magnetic field mapping using the Tsyganenko T01 model with the observed solar wind input parameters showed that the low- and mid-altitude isotropization boundaries were closely located, which leads us to suggest that the Polar IDB and low-altitude IBs are related. Furthermore, we introduced a procedure to control the difference between the observed and model magnetic field to reduce the large scatter in the mapping. We showed that the isotropic distribution boundary (IDB lies in the region where Rc/ρ~6, that is at the boundary of the region where the non-adiabatic pitch angle scattering is strong enough. We therefore conclude that the scattering in the large field line curvature regions in the nightside current sheet is the main mechanism producing isotropization for the main portion of proton population in the tail current sheet. This mechanism controls the observed positions of both IB and IDB boundaries. Thus, this tail region can be probed, in its turn, with observations of these isotropy boundaries. Keywords. Magnetospheric physics (Energetic particles, Precipitating; Magnetospheric configuration and dynamics; Magnetotail
Proton isotropy boundaries as measured on mid- and low-altitude satellites
Directory of Open Access Journals (Sweden)
N. Yu. Ganushkina
2005-07-01
Full Text Available Polar CAMMICE MICS proton pitch angle distributions with energies of 31-80 keV were analyzed to determine the locations where anisotropic pitch angle distributions (perpendicular flux dominating change to isotropic distributions. We compared the positions of these mid-altitude isotropic distribution boundaries (IDB for different activity conditions with low-altitude isotropic boundaries (IB observed by NOAA 12. Although the obtained statistical properties of IDBs were quite similar to those of IBs, a small difference in latitudes, most pronounced on the nightside and dayside, was found. We selected several events during which simultaneous observations in the same local time sector were available from Polar at mid-altitudes, and NOAA or DMSP at low-altitudes. Magnetic field mapping using the Tsyganenko T01 model with the observed solar wind input parameters showed that the low- and mid-altitude isotropization boundaries were closely located, which leads us to suggest that the Polar IDB and low-altitude IBs are related. Furthermore, we introduced a procedure to control the difference between the observed and model magnetic field to reduce the large scatter in the mapping. We showed that the isotropic distribution boundary (IDB lies in the region where Rc/ρ~6, that is at the boundary of the region where the non-adiabatic pitch angle scattering is strong enough. We therefore conclude that the scattering in the large field line curvature regions in the nightside current sheet is the main mechanism producing isotropization for the main portion of proton population in the tail current sheet. This mechanism controls the observed positions of both IB and IDB boundaries. Thus, this tail region can be probed, in its turn, with observations of these isotropy boundaries.
Keywords. Magnetospheric physics (Energetic particles, Precipitating; Magnetospheric configuration and dynamics; Magnetotail
Variation in the isotopic content of precipitation with altitude
International Nuclear Information System (INIS)
Stowhas, L.; Silva, C.; Moser, H.; Stichler, W.
1975-03-01
Monthly precipitation and single storms have been collected during three years at 12 stations along a W-E profile in Chile, going from Juan Fernandez Islands to Valparaiso, Santiago and Infiernillo in the Andes, and analysed for their deuterium content. The deltaD values are correlated with the altitude of the station, the mean temperature - which also largely depends on the altitude - and the distance from the sea. The correlation parameters show however important variations from year to year and even more from month to month. For instance, in the stretch Santiago (520 m a.s.l.) - La Parva (2680 m) the mean isotopic gradient with altitude were: -1.84 deltaD per mil/100 m in 1970, -1.09 in 1971 and -2.0 in 1972. The low value observed in 1971 could be a consequence of the peculiar weather characteristics of this unusually dry year. In the stretch from the coast to Santiago the trend of the isotopic composition of precipitation is more complicated, because the so-called continental effect is superimposed to the altitude effect. The deuterium content variations have been also determined in snowpack profiles at La Parva station. The results show that snow melting occurs slowly at the bottom during the whole winter, at the expenses of the heat stored during summer in the soil. The melting of the surface snow layers only starts at the end of the winter and then proceeds very fast
Age at Immigration and Educational Attainment of Young Immigrants
van Ours, J.C.; Veenman, J.M.C.
2005-01-01
For immigrants who arrive in a country at a young age it is easier to assimilate than for teenagers.This paper investigates up to what immigration age the educational attainment of young immigrants in the Netherlands is similar to the educational attainment of secondgeneration immigrants, who were
Statistical methods for evaluating the attainment of cleanup standards
Energy Technology Data Exchange (ETDEWEB)
Gilbert, R.O.; Simpson, J.C.
1992-12-01
This document is the third volume in a series of volumes sponsored by the US Environmental Protection Agency (EPA), Statistical Policy Branch, that provide statistical methods for evaluating the attainment of cleanup Standards at Superfund sites. Volume 1 (USEPA 1989a) provides sampling designs and tests for evaluating attainment of risk-based standards for soils and solid media. Volume 2 (USEPA 1992) provides designs and tests for evaluating attainment of risk-based standards for groundwater. The purpose of this third volume is to provide statistical procedures for designing sampling programs and conducting statistical tests to determine whether pollution parameters in remediated soils and solid media at Superfund sites attain site-specific reference-based standards. This.document is written for individuals who may not have extensive training or experience with statistical methods. The intended audience includes EPA regional remedial project managers, Superfund-site potentially responsible parties, state environmental protection agencies, and contractors for these groups.
Albuminuria and overall capillary permeability of albumin in acute altitude hypoxia
DEFF Research Database (Denmark)
Hansen, J M; Olsen, Niels Vidiendal; Feldt-Rasmussen, B
1994-01-01
The mechanism of proteinuria at high altitude is unclear. Renal function and urinary excretion rate of albumin (Ualb) at rest and during submaximal exercise and transcapillary escape rate of 125I-labeled albumin (TERalb) were investigated in 12 normal volunteers at sea level and after rapid...... and passive ascent to 4,350 m. The calcium antagonist isradipine (5 mg/day; n = 6) or placebo (n = 6) was administered to abolish hypoxia-induced rises in blood pressure. Lithium clearance and urinary excretion of beta 2-microglobulin were used to evaluate renal tubular function. High altitude increased Ualb...... from 2.8 to > 5.0 micrograms/min in both groups (P high altitude significantly increased filtration fraction (P
Modeling of Air Attenuation Effects on Gamma Detection at Altitude
International Nuclear Information System (INIS)
Detwiler, R. S.
2002-01-01
This paper focuses on modeling the detection capabilities of NaI sensor systems at high altitudes for ground sources. The modeling was done with the Monte Carlo N-Transport (MCNP) code developed at Los Alamos National Laboratory. The specific systems modeled were the fixed wing and helicopter aircraft sensor systems, assets of the U. S. Department of Energy's National Nuclear Security Administration Nevada Operations Office (NNSA/NV) Aerial Measuring System (AMS). In previous (2001) modeling, Sodium Iodine (NaI) detector responses were simulated for both point and distributed surface sources as a function of gamma energy and altitude. For point sources, photo-peak efficiencies were calculated for a zero radial distance and an offset equal to the altitude. For distributed sources approximating an infinite plane, gross count efficiencies were calculated and normalized to a uniform surface deposition of 1 (micro)Ci/m 2 . To validate the calculations, benchmark measurements were made for simple source-detector configurations. The 2002 continuation of the modeling presented here includes checking models against available data, and modifications to allow more effective and accurate directional biasing of ground point and distributed sources. Fixed-wing data results will be shown for two point sources as a function of altitude
Are macroinvertebrates in high altitude streams affected by oxygen deficiency?
DEFF Research Database (Denmark)
Jacobsen, Dean; Rostgaard, S.; Vásconez, J. J.
2003-01-01
1. The solubility of oxygen in water increases with decreasing temperature. This has led to a general perception of cold, high mountain streams as more oxygen rich than warmer lowland streams, and that macroinvertebrates inhabiting high altitude streams have had no need to adapt to critical oxygen...... conditions. However, this fails to take into account that oxygen solubility declines with decreasing atmospheric pressure, which may be of importance at high altitudes. 2. Based on samples of macroinvertebrate benthos and in situ measurements of respiratory oxygen demand of macroinvertebrates in small...... the mean weight-specific respiratory rate of macroinvertebrates declined by only 50%, from 400 to 3800 m. We suggest that this disproportionately large gap between availability and demand of oxygen at high altitudes may imply a potential oxygen deficiency for the fauna, and we discuss how oxygen deficiency...
A Robust Photogrammetric Processing Method of Low-Altitude UAV Images
Directory of Open Access Journals (Sweden)
Mingyao Ai
2015-02-01
Full Text Available Low-altitude Unmanned Aerial Vehicles (UAV images which include distortion, illumination variance, and large rotation angles are facing multiple challenges of image orientation and image processing. In this paper, a robust and convenient photogrammetric approach is proposed for processing low-altitude UAV images, involving a strip management method to automatically build a standardized regional aerial triangle (AT network, a parallel inner orientation algorithm, a ground control points (GCPs predicting method, and an improved Scale Invariant Feature Transform (SIFT method to produce large number of evenly distributed reliable tie points for bundle adjustment (BA. A multi-view matching approach is improved to produce Digital Surface Models (DSM and Digital Orthophoto Maps (DOM for 3D visualization. Experimental results show that the proposed approach is robust and feasible for photogrammetric processing of low-altitude UAV images and 3D visualization of products.
SPLENIC INFARCTION: an intriguing and important cause of pain abdomen in high altitude
Directory of Open Access Journals (Sweden)
P. K. Hota
2015-01-01
Full Text Available Background: Patients with Sickle cell trait (SCT are usually asymptomatic. They are usually unaware of their condition unless they have a family history. There are specific situations, where these people suffer from the effects of sickle cell trait. Splenic syndrome at high altitude is one of the specific problems. It is usually seen after a patient with SCT has been inducted to high altitude like in case of mountaineers and military personnel deployed in high altitude warfare. Pain abdomen due to splenic infarction in individuals with SCT is one of the manifestations. These patients, if diagnosed in time, they can be spared from unnecessary surgical interventions. We present herewith our experience of splenic infarction due to SCT in high altitude and their management.
Directory of Open Access Journals (Sweden)
J. Boulon
2011-06-01
Full Text Available In this work we present an analysis of the occurrence of nucleation events during more than three years of measurements at two different rural altitude sites, the puy de Dôme research station (1465 m a.s.l. and the Opme station (660 m a.s.l., central France. The collected database is a unique combination of scanning mobility particle sizer (10–400 nm, air ion spectrometers (from 0.8 to 42 nm for NTP-conditions, and, neutral clusters and air ion spectrometers (from 0.8 to 42 nm for NTP-conditions measurements at these two different altitudes nearly located research stations, from February 2007 to June 2010. The seasonality of the frequency of nucleation events was studied at the puy de Dôme station and maximum of events frequency was found during early spring and early autumn. During the measurement period, neither the particle formation rates (J2= 1.382 ± 0.195 s−1 nor the growth rates (GR1.3−20 nm = 6.20 ± 0.12 nm h−1 differ from one site to the other on average. Hovewer, we found that, on 437 sampling days in common to the two sites, the nucleation frequency was higher at the puy de Dôme station (35.9 %, 157 days than at the low elevation station of Opme (20.8 %, 91 days. LIDAR measurements and the evolution of the potential equivalent temperature revealed that the nucleation could be triggered either (i within the whole low tropospheric column at the same time from the planetary boundary layer to the top of the interface layer (29.2 %, 47 events, (ii above the planetary boundary layer upper limit (43.5 %, 70 events, and (iii at low altitude and then transported, conserving dynamic and properties, at high altitude (24.8 %, 40 events. This is the first time that the vertical extent of nucleation can be studied over a long observational period, allowing for a rigorous
Beyond Dominance and Competence: A Moral Virtue Theory of Status Attainment.
Bai, Feng
2017-08-01
Recognition has grown that moral behavior (e.g., generosity) plays a role in status attainment, yet it remains unclear how, why, and when demonstrating moral characteristics enhances status. Drawing on philosophy, anthropology, psychology, and organizational behavior, I critically review a third route to attaining status: virtue, and propose a moral virtue theory of status attainment to provide a generalized account of the role of morality in status attainment. The moral virtue theory posits that acts of virtue elicit feelings of warmth and admiration (for virtue), and willing deference, toward the virtuous actor. I further consider how the scope and priority of moralities and virtues endorsed by a moral community are bound by culture and social class to affect which moral characteristics enhance status. I end by outlining an agenda for future research into the role of virtue in status attainment.
Ozoroski, Thomas A.; Nickol, Craig L.; Guynn, Mark D.
2015-01-01
There have been ongoing efforts in the Aeronautics Systems Analysis Branch at NASA Langley Research Center to develop a suite of integrated physics-based computational utilities suitable for modeling and analyzing extended-duration missions carried out using solar powered aircraft. From these efforts, SolFlyte has emerged as a state-of-the-art vehicle analysis and mission simulation tool capable of modeling both heavier-than-air (HTA) and lighter-than-air (LTA) vehicle concepts. This study compares solar powered airplane and airship station-keeping capability during a variety of high altitude missions, using SolFlyte as the primary analysis component. Three Unmanned Aerial Vehicle (UAV) concepts were designed for this study: an airplane (Operating Empty Weight (OEW) = 3285 kilograms, span = 127 meters, array area = 450 square meters), a small airship (OEW = 3790 kilograms, length = 115 meters, array area = 570 square meters), and a large airship (OEW = 6250 kilograms, length = 135 meters, array area = 1080 square meters). All the vehicles were sized for payload weight and power requirements of 454 kilograms and 5 kilowatts, respectively. Seven mission sites distributed throughout the United States were selected to provide a basis for assessing the vehicle energy budgets and site-persistent operational availability. Seasonal, 30-day duration missions were simulated at each of the sites during March, June, September, and December; one-year duration missions were simulated at three of the sites. Atmospheric conditions during the simulated missions were correlated to National Climatic Data Center (NCDC) historical data measurements at each mission site, at four flight levels. Unique features of the SolFlyte model are described, including methods for calculating recoverable and energy-optimal flight trajectories and the effects of shadows on solar energy collection. Results of this study indicate that: 1) the airplane concept attained longer periods of on
Two-dimensional unsteady lift problems in supersonic flight
Heaslet, Max A; Lomax, Harvard
1949-01-01
The variation of pressure distribution is calculated for a two-dimensional supersonic airfoil either experiencing a sudden angle-of-attack change or entering a sharp-edge gust. From these pressure distributions the indicial lift functions applicable to unsteady lift problems are determined for two cases. Results are presented which permit the determination of maximum increment in lift coefficient attained by an unrestrained airfoil during its flight through a gust. As an application of these results, the minimum altitude for safe flight through a specific gust is calculated for a particular supersonic wing of given strength and wing loading.
A dictionary of altitudes in the United States (second edition)
Gannett, Henry
1891-01-01
I have the honor to transmit herewith the manuscript of a second edition of a Dictionary of Altitudes, the first edition having been published in 1884. The present work is considerably enlarged, mainly by the addition of determinations of altitudes by railroads. Besides the additions of matter, the principal change from the earlier edition consists in the substitution of a single alphabetic arrangement throughout the work for an alphabetic arrangement by States.
Directory of Open Access Journals (Sweden)
Jans Fromow-Guerra
2016-01-01
Full Text Available The aim of this study is to assess the change in intraocular pressure after a road trip, in eyes with different levels of filling with gas tamponade. Five rabbit eyes were subject to pars plana vitrectomy and gas tamponade (filling percentage: 25%, 50%, and 100% of nonexpansile SF6, 100% saline solution, and 100% room air. A sixth eye was injected with 0.35 cc of undiluted SF6 without vitrectomy. Guided by global positioning system, they were driven to the highest point of the highway connecting Mexico City with Puebla city and back, stopping every 300 m to assess intraocular pressure. The rabbit’s scleral rigidity and estimation for human eyes were done by using the Friedenwald nomogram. Maximum altitude was 3209 m (Δ949 m. There were significant differences in intraocular pressure on the rabbit eyes filled with SF6 at 100%, 50%, 25%, and 100% room air. Per every 100 m of altitude rise, the intraocular pressure increased by 1.53, 1.0046, 0.971, and 0.97 mmHg, respectively. Using the human Friedenwald rigidity coefficient, the human eye estimate for intraocular pressure change was 2.1, 1.8, 1.4, and 1.1 mmHg per every 100 m of attitude rise. Altitude changes have a significant impact on intraocular pressure. The final effect depends on the percentage of vitreous cavity fill and scleral rigidity.
Heinicke, Ilmar; Boehler, Annette; Rechsteiner, Thomas; Bogdanova, Anna; Jelkmann, Wolfgang; Hofer, Markus; Rawlings, Pablo; Araneda, Oscar F; Behn, Claus; Gassmann, Max; Heinicke, Katja
2009-07-01
Oxidative stress occurs at altitude, and physical exertion might enhance this stress. In the present study, we investigated the combined effects of exercise and moderate altitude on redox balance in ten endurance exercising biathletes, and five sedentary volunteers during a 6-week-stay at 2,800 m. As a marker for oxidative stress, hydrogen peroxide (H(2)O(2)) was analyzed by the biosensor measuring system Ecocheck, and 8-iso prostaglandin F2alpha (8-iso PGF2alpha) was determined by enzyme immunoassay in exhaled breath condensate (EBC). To determine the whole blood antioxidative capacity, we measured reduced glutathione (GSH) enzymatically using Ellman's reagent. Exercising athletes and sedentary volunteers showed increased levels of oxidative markers at moderate altitude, contrary to our expectations; there was no difference between both groups. Therefore, all subjects' data were pooled to examine the oxidative stress response exclusively due to altitude exposure. H(2)O(2) levels increased at altitude and remained elevated for 3 days after returning to sea level (p altitude, but declined immediately after returning to sea level (p altitude resulted in elevated GSH levels (p altitude (p altitude for up to 6 weeks increases markers of oxidative stress in EBC independent of additional endurance training. Notably, this oxidative stress is still detectable 3 days upon return to sea level.
Directory of Open Access Journals (Sweden)
Stephen Thielke
2016-11-01
Full Text Available Almost all studies examining the effects of altitude on human health have estimated the geographical altitude of defined regions, yet the primary interest lies in where people live, not the land around them. Populations are not homogenously distributed across altitudes. We propose a straightforward and computationally simple method for estimating the average altitude of habitation within the regional units for which health statistics are typically reported (such as counties. The United States Board on Geographical Names database contains records for over 2.7 million places, which can be processed to select places that are associated with human habitation. These points can easily be averaged by region yielding a representative altitude of human habitation within city, county, state regions, or by longitude and latitude zones. We provide an example of using this approach in a study of human health, and compare it with three other previously used methods of estimating altitude for counties.
High Altitude Balloons as a Platform for Space Radiation Belt Science
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
Solar Cell Short Circuit Current Errors and Uncertainties During High Altitude Calibrations
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%
Educational Attainment in the United States: 2003. Population Characteristics
Stoops, Nicole
2004-01-01
The population in the United States is becoming more educated, but significant differences in educational attainment remain with regard to age, sex, race, and origin. Nevertheless, the educational attainment of young adults (25 to 29 years), which provides a glimpse of our country's future, indicates dramatic improvement by groups who have…
Maximum Attainable Accuracy of Inexact Saddle Point Solvers
Czech Academy of Sciences Publication Activity Database
Jiránek, P.; Rozložník, Miroslav
2008-01-01
Roč. 29, č. 4 (2008), s. 1297-1321 ISSN 0895-4798 R&D Projects: GA MŠk 1M0554; GA AV ČR 1ET400300415 Institutional research plan: CEZ:AV0Z10300504 Keywords : saddle point problems * Schur complement reduction * null-space projection method * rounding error analysis Subject RIV: BA - General Mathematics Impact factor: 1.328, year: 2008
Boussen, Salah; Coulange, Mathieu; Fournier, Marc; Gainnier, Marc; Michelet, Pierre; Micoli, Christophe; Negrel, Lionel
2014-08-01
Previous studies on ventilators used for air transport showed significant effects of altitude, in particular with regard to accuracy of the tidal volume (VT) and breathing frequency. The aim of the study was to evaluate transport ventilators under hypobaric conditions. We conducted a bench study of 6 transport ventilators in a Comex hypobaric chamber to simulate mild altitude (1,500 m [4,920 feet] and 2,500 m [8,200 feet]). The ventilators were connected to a test lung to evaluate their accuracy: (1) to deliver a set VT under normal resistance and compliance conditions at F(IO2) = 0.6 and 1, (2) to establish a set PEEP (0, 5, 10, and 15 cm H2O), and (3) to establish a set inspiratory pressure in pressure controlled mode, (4) at a F(IO2) setting, and (5) and at a frequency setting. Four ventilators kept an average relative error in VT of ventilator was affected by the altitude only at F(IO2) = 1. The Osiris 3 ventilator had > 40% error even at 1,500 m. We found no change in frequency as a function of altitude for any ventilators studied. No clinically important differences were found between all altitudes with the PEEP or inspiratory pressure setting. Although F(IO2) was affected by altitude, the average error did not exceed 11%, and it is unclear whether this fact is an experimental artifact. We have shown that most of the new transport ventilators tested require no setting adjustment at moderate altitude and are as safe at altitude as at sea level under normal respiratory conditions. Older technologies still deliver more volume with altitude in volumetric mode.
The individual response to training and competition at altitude.
Chapman, Robert F
2013-12-01
Performance in athletic activities that include a significant aerobic component at mild or moderate altitudes shows a large individual variation. Physiologically, a large portion of the negative effect of altitude on exercise performance can be traced to limitations of oxygen diffusion, either at the level of the alveoli or the muscle microvasculature. In the lung, the ability to maintain arterial oxyhaemoglobin saturation (SaO₂) appears to be a primary factor, ultimately influencing oxygen delivery to the periphery. SaO₂ in hypoxia can be defended by increasing ventilatory drive; however, during heavy exercise, many athletes demonstrate limitations to expiratory flow and are unable to increase ventilation in hypoxia. Additionally, increasing ventilatory work in hypoxia may actually be negative for performance, if dyspnoea increases or muscle blood flow is reduced secondary to an increased sympathetic outflow (eg, the muscle metaboreflex response). Taken together, some athletes are clearly more negatively affected during exercise in hypoxia than other athletes. With careful screening, it may be possible to develop a protocol for determining which athletes may be the most negatively affected during competition and/or training at altitude.
Metabolic Effects of High Altitude Trekking in Patients With Type 2 Diabetes
de Mol, Pieter; Fokkert, Marion J.; de Vries, Suzanna T.; de Koning, Eelco J. P.; Dikkeschei, Bert D.; Gans, Rijnold O. B.; Tack, Cees J.; Bilo, Henk J. G.
2012-01-01
OBJECTIVE-Limited information is available regarding the metabolic effects of high altitude trekking in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS-Thirteen individuals with type 2 diabetes took part, in a 12-day expedition to the summit of Mount Toubkal (altitude, 4,167 m), Morocco,
Metabolic effects of high altitude trekking in patients with type 2 diabetes
Mol, P. de; Fokkert, M.J.; Vries, S.T. de; Koning, E.J. de; Dikkeschei, B.D.; Gans, R.O.; Tack, C.J.J.; Bilo, H.J.
2012-01-01
OBJECTIVE Limited information is available regarding the metabolic effects of high altitude trekking in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS Thirteen individuals with type 2 diabetes took part in a 12-day expedition to the summit of Mount Toubkal (altitude, 4,167 m), Morocco,
Science 101: Why Does It Take Longer to Boil Potatoes at High Altitudes?
Robertson, Bill
2017-01-01
Why Does It Take Longer to Boil Potatoes at High Altitudes? This column provides background science information for elementary teachers. This month's issue looks at why water boils at different temperatures at different altitudes.
Experimental StudyHigh Altitude Forced Convective Cooling of Electromechanical Actuation Systems
2016-01-01
34 Massachusetts Institute of Technology , 1989. [3] FedBizOps.Gov, " Integrated Vehicle Energy Technology (INVENT) Development Program for the 6th...AFRL-RQ-WP-TR-2016-0043 EXPERIMENTAL STUDY—HIGH ALTITUDE FORCED CONVECTIVE COOLING OF ELECTROMECHANICAL ACTUATION SYSTEMS Evan M. Racine...TITLE AND SUBTITLE EXPERIMENTAL STUDY—HIGH ALTITUDE FORCED CONVECTIVE COOLING OF ELECTROMECHANICAL ACTUATION SYSTEMS 5a. CONTRACT NUMBER In-house
Heil, K M; Keenan, A C M
2014-01-01
In recent years, small scale counter-insurgency and expeditionary operations have frequently taken place in mountainous, high-altitude areas. Preparation of soldiers for these environments has typically focussed on extended stays at altitude to ensure physiological acclimatisation. However, with the likelihood that future UK deployments may be unpredictable and thus with little time for preparation, is there a means by which the same acclimatisation may be achieved? The field of athletics has been researching such adaptations since the rise of the elite North African long-distance runners in the 1960s. These athletes all lived high above sea level and had become accustomed to performing in the relatively hypoxic environment found at high altitudes. The research has focussed on eliciting physiological acclimatisation in as short a time as possible, while maintaining the ability to train at the correct intensity. In the following review of altitude training we highlight areas for future investigation and assess whether protocols developed for athletes can be applied to military personnel.
HSP70 expression in the copper butterfly Lycaena tityrus across altitudes and temperatures
DEFF Research Database (Denmark)
Karl, I.; Sørensen, Jesper Givskov; Loeschcke, Volker
2009-01-01
temperatures show differences in HSP70 expression. HSP70 expression increased substantially at the higher rearing temperature in low-altitude butterflies, which might represent an adaptation to occasionally occurring heat spells. On the other hand, high-altitude butterflies showed much less plasticity...... in response to rearing temperatures, and overall seem to rely more on genetically fixed thermal stress resistance. Whether the latter indicates a higher vulnerability of high-altitude populations to global warming needs further investigation. HSP70 expression increased with both colder and warmer induction......The ability to express heat-shock proteins (HSP) under thermal stress is an essential mechanism for ectotherms to cope with unfavourable conditions. In this study, we investigate if Copper butterflies originating from different altitudes and/or being exposed to different rearing and induction...
Joint pain and Doppler-detectable bubbles in altitude (Hypobaric) decompression
Powell, Michael R.
1993-01-01
The observation that altitude decompression sickness (DCS) is associated with pain in the lower extremities is not new, although it is not a consistent finding. DCS in divers is generally in the upper body, an effect often attributed to non-loading of the body while immersed. In caisson workers, DCS is reported more in the lower extremities. Surprisingly, many researchers do not mention the location of DCS joint pain, apparently considering it to be random. This is not the case for the tissue ratios encountered in studying decompression associated with simulated EVA. In NASA/JSC tests, altitude DCS generally presented first in either the ankle, knee, or hip (83 percent = 73/88). There was a definite statistical relation between the maximum Spencer precordial Doppler Grade and the incidence of DCS in the extremity, although this is not meant to imply a casual relation between circulating gas bubbles and joint pain. The risk of DCS with Grade 4 was considerably higher than that of Grades 0 to 3. The DCS risk was independent of the 'tissue ratio.' There was a predominance of lower extremity DCS even when exercise was performed with the upper body. The reason for these locations we hypothesize to be attributed to the formation of tissue gas micronuclei from kinetic and tensile forces (stress-assisted nucleation) and are the result of the individuals ambulating in a 1g environment. Additionally, since these showers of Doppler bubbles can persist for hours, it is difficult to imagine that they are emanating solely from tendons and ligaments, the supposed site of joint pain. This follows from Henry's law linking the volume of joint tissue (the solvent) and the solubility coefficient of inert gas; there is volumetrically insufficient connective tissue to produce the prolonged release of gas bubbles. If gas bubbles are spawned and released from connective tissue, their volume is increased by those from muscle tissue. Therefore, the nexus between Doppler-detectable gas
Effect of altitude on the protein metabolism of Bolivian children
International Nuclear Information System (INIS)
San Miguel Simron, J.L.; Berger, J.; Spielvogel, H.; Tellez Castellon, W.; Lujan Medina, C.; Caceres, E.
1996-01-01
The malnutrition is prevalent and is a major problem among Bolivian children. It is caused by several interacting factors: (1) inadequate protein energy intake due to low socio-economic status; (ii) exposure to acute, repeated and chronic bacterial infections; (iii) exposure to multiple and chronic parasitic infections; (iv) high altitude of the capital, La Paz, 3600 m, with a numerous populations compared to the rest of the country. The research objectives in the first phase are: (i) determination of protein utilization with a non-invasive method using stable isotope tracer among children living at high and low altitude; (ii) determination of protein metabolism among eutrophic children without parasitic or acute bacterial infections at both altitudes; (iii) determination of protein requirement among these children. Two groups of 10 pubertal children, matched for age and sex, of same socio-economic status, eutrophic, without malnutrition, infections or intestinal parasites will be studied; the different status being arrived by anthropometric, nutritional intake, biochemical and pediatrical evaluation. For the metabolic study, stable isotopes L-[1-13C] leucine labelled casein will be used and 13 CO 2 excreted will be measured. All the basic nutritional assessment and VCO 2 measurements will be performed in Bolivia, while the samples of expired gas will be stored in Vacutainers for further analysis by isotope radio mass spectrometer (IRMS), in Clermont-Ferrand, France. The plans for future work is based on the study of the effects of the different variables and their interactions. The following will be evaluated: (i) the socio-economic status; (ii) the bacterial infections: (iii) the parasitic infections; (iv) the altitude. As published by Obert, et al., the socio-economic variable is more connected with the nutritional status than with the altitude. 12 refs, 1 fig., 1 tab
Effect of altitude on the protein metabolism of Bolivian children
Energy Technology Data Exchange (ETDEWEB)
San Miguel Simron, J L; Berger, J; Spielvogel, H; Tellez Castellon, W; Lujan Medina, C; Caceres, E [Instituto Boliviano de Boliviano de Biologia de Altura, La Paz (Bolivia). Dept. de Nutricion; Beaufrere, B; Gachons, P; Coudert, J [Laboratoire de Nutrition Humaine, Clermont-Ferrand (France)
1997-12-31
The malnutrition is prevalent and is a major problem among Bolivian children. It is caused by several interacting factors: (1) inadequate protein energy intake due to low socio-economic status; (ii) exposure to acute, repeated and chronic bacterial infections; (iii) exposure to multiple and chronic parasitic infections; (iv) high altitude of the capital, La Paz, 3600 m, with a numerous populations compared to the rest of the country. The research objectives in the first phase are: (i) determination of protein utilization with a non-invasive method using stable isotope tracer among children living at high and low altitude; (ii) determination of protein metabolism among eutrophic children without parasitic or acute bacterial infections at both altitudes; (iii) determination of protein requirement among these children. Two groups of 10 pubertal children, matched for age and sex, of same socio-economic status, eutrophic, without malnutrition, infections or intestinal parasites will be studied; the different status being arrived by anthropometric, nutritional intake, biochemical and pediatrical evaluation. For the metabolic study, stable isotopes L-[1-13C] leucine labelled casein will be used and {sup 13}CO{sub 2} excreted will be measured. All the basic nutritional assessment and VCO{sub 2} measurements will be performed in Bolivia, while the samples of expired gas will be stored in Vacutainers for further analysis by isotope radio mass spectrometer (IRMS), in Clermont-Ferrand, France. The plans for future work is based on the study of the effects of the different variables and their interactions. The following will be evaluated: (i) the socio-economic status; (ii) the bacterial infections: (iii) the parasitic infections; (iv) the altitude. As published by Obert, et al., the socio-economic variable is more connected with the nutritional status than with the altitude. 12 refs, 1 fig., 1 tab.
Li, S H; Li, S; Sun, L; Bai, Z Z; Yang, Q Y; Ga, Q; Jin, G E
2016-08-23
To investigate the correlation between pulmonary artery pressure (PAP) and the expression level of Egl nine homologue 1 (EGLN1) gene or its protein in lung tissue of rats at different altitudes. Totally 121 male Wistar rats were randomly divided into low altitude group (n=11), moderate altitude group and high altitude group, the rats in moderate altitude and high altitude group were further divided into 1(st) day, 3(rd) days, 7(th) days, 15(th) day and 30(th) day group according to the exposure time to hypoxic environment, each group 11 rats. The low altitude group, the PAP of rats were determined by physiological signal acquisition system, and tissue samples were collected in liquid nitrogen container for storage at an altitude of 498 m area. Moderate altitude group rats were placed in altitude of 2 260 meters of natural environment, 5 high altitude groups rats were placed in the hypobaric hypoxic chamber, simulating altitude of 4 500 meters. The PAP of rats in moderate altitude group and high altitude group were also determined by physiological signal acquisition system, and tissue samples were collected when rats were exposed to hypoxia at 1(st), 3(rd), 7(th), 15(th) and 30(th) day; Western blot was used to determine expression levels of EGLN1 protein, and person correlation analysis was used to analyze whether the protein was related to the formation of pulmonary arterial hypertension (PH) under hypoxia. Real-time quantitive PCR method determined expression levels of EGLN1 mRNA in lung tissues, and the relative expression method was used to analyze PCR data, and finally assess whether the EGLN1 gene was the initial cause of the formation of PH during hypoxia. The mean PAP of rats was (20.0±3.2) mmHg (1 mmHg=0.133 kPa) in low altitude group; in moderate altitude group, mean PAP began to increase slightly when rats were exposed to hypoxia on the 15(th) day and reached at (22.7±4.1) mmHg on hypoxic 30(th) day, but compared with the low altitude group, there was
Training-dependent cognitive advantage is suppressed at high altitude.
Li, Peng; Zhang, Gang; You, Hai-Yan; Zheng, Ran; Gao, Yu-Qi
2012-06-25
Ascent to high altitude is associated with decreases in cognitive function and work performance as a result of hypoxia. Some workers with special jobs typically undergo intensive mental training because they are expected to be agile, stable and error-free in their job performance. The purpose of this study was to determine the risk to cognitive function acquired from training following hypoxic exposure. The results of WHO neurobehavioral core tests battery (WHO-NCTB) and Raven's standard progressive matrices (RSPM) tests of a group of 54 highly trained military operators were compared with those of 51 non-trained ordinary people and were investigated at sea level and on the fifth day after arrival at high altitudes (3900m). Meanwhile, the plasma levels of brain-derived neurotrophic factor (BDNF), interleukin 1β (IL-1β) and vascular endothelial growth factor (VEGF) were examined. The result showed that at sea level, the trained group exhibited significantly better performance on neurobehavioral and RSPM tests. At high altitude, both groups had decreased accuracy in most cognitive tests and took longer to finish them. More importantly, the highly trained subjects showed more substantial declines than the non-trained subjects in visual reaction accuracy, auditory reaction speed, digit symbol scores, ability to report correct dots in a pursuit aiming test and total RSPM scores. This means that the training-dependent cognitive advantages in these areas were suppressed at high altitudes. The above phenomenon maybe associated with decreased BDNF and elevated inflammatory factor during hypoxia, and other mechanisms could not be excluded. Copyright © 2012 Elsevier Inc. All rights reserved.
Aspirated Compressors for High Altitude Engines, Phase I
National Aeronautics and Space Administration — Aurora Flight Sciences proposes to incorporate aspirated compressor technology into a high altitude, long endurance (HALE) concept engine. Aspiration has been proven...
High altitude and hemoglobin function in the vultures Gyps rueppelli and Aegypius monachus
DEFF Research Database (Denmark)
Weber, Roy E.; Hiebl, Inge; Braunitzer, Gerhard
1988-01-01
Functional characteristics of the stripped composite hemoglobins (Hbs) of lhevultures Gyps rueppellii and Aegypills monachus that can fly at extremely high altitudes, and of component Hbs of G. rueppellii are reported, in relation to influences of pH, temperalure and inositol hexaphosphate. G...... structures of the constituent polypeptide chains to trace molecular adaptations to high-altitude respiration, and to physiological factors (pulmonary hypoxia and hypocapnia, body temperature shifts, and lung and nasal gas and heat exchange) to discern their possible survival value at altitudes of 11300 m....
Civilian Training in High-Altitude Flight Physiology
1991-08-01
A survey was conducted to determine if training in high-altitude physiology should : be required for civilian pilots; what the current status of such training was; and, : if required, what should be included in an ideal curriculum. The survey include...
Altitude Testing of Large Liquid Propellant Engines
Maynard, Bryon T.; Raines, Nickey G.
2010-01-01
The National Aeronautics and Space Administration entered a new age on January 14, 2004 with President Bush s announcement of the creation the Vision for Space Exploration that will take mankind back to the Moon and on beyond to Mars. In January, 2006, after two years of hard, dedicated labor, engineers within NASA and its contractor workforce decided that the J2X rocket, based on the heritage of the Apollo J2 engine, would be the new engine for the NASA Constellation Ares upper stage vehicle. This engine and vehicle combination would provide assured access to the International Space Station to replace that role played by the Space Shuttle and additionally, would serve as the Earth Departure Stage, to push the Crew Excursion Vehicle out of Earth Orbit and head it on a path for rendezvous with the Moon. Test as you fly, fly as you test was chosen to be the guiding philosophy and a pre-requisite for the engine design, development, test and evaluation program. An exhaustive survey of national test facility assets proved the required capability to test the J2X engine at high altitude for long durations did not exist so therefore, a high altitude/near space environment testing capability would have to be developed. After several agency concepts the A3 High Altitude Testing Facility proposal was selected by the J2X engine program on March 2, 2007 and later confirmed by a broad panel of NASA senior leadership in May 2007. This facility is to be built at NASA s John C. Stennis Space Center located near Gulfport, Mississippi. 30 plus years of Space Shuttle Main Engine development and flight certification testing makes Stennis uniquely suited to support the Vision For Space Exploration Return to the Moon. Propellant handling infrastructure, engine assembly facilities, a trained and dedicated workforce and a broad and varied technical support base will all ensure that the A3 facility will be built on time to support the schedule needs of the J2X engine and the ultimate flight
Preliminary study on alterations of altitude road traffic in China from 2006 to 2013
Zhao, Hui; Yin, Zhiyong; Xiang, Hongyi; Liao, Zhikang; Wang, Zhengguo
2017-01-01
Introduction Road traffic can play an important role in strengthening regional economic activities, especially at high altitude, and it is necessary to know important traffic-related information. Although previous studies reported on road traffic in China, there has been little research on high-altitude road traffic to date. Method The annual official census of road traffic safety from 2006 to 2013 was used to obtain data on the general population, registered drivers, registered vehicles, newly built roads, road traffic accidents (RTAs), mortality rate per 100 000 populations and per 10 000 vehicles in high-altitude provinces, including Tibet, Qinghai, Xinjiang, Gansu, Yunnan, Sichuan, and Chongqing. These provincial data were reviewed retrospectively, with the national data as the reference. Statistical analysis (i.e., t test) was used to compare the estimated average annual change rate of population, number of registered drivers, registered vehicles, and newly built roads in high-altitude provinces with the national rates. Results Compared with the national data, there are significantly higher annual rates of population growth in Tibet and Xinjiang, registered drivers in Gansu, registered vehicles in Gansu, Sichuan, and Chongqing, and newly built roads in Tibet and Qinghai. Among the investigated provinces, Tibet, Qinghai, and Yunnan had a higher proportion of the roads with the high class. RTAs and RTA-induced casualties in the high-altitude provinces indicated a decreasing trend. The mortality rate per 10 000 vehicles and per 100 000 populations showed a decreasing trend, while the RTA-related mortality rate in Tibet, Qinghai, Xinjiang and Gansu remained high. Conclusions Major changes for road traffic in high-altitude provinces have occurred over the past decade; however, the RTA-related mortality rate in high-altitude provinces has remained high. This study furthers understanding about road traffic safety in China; further studies on road traffic safety at
Preliminary study on alterations of altitude road traffic in China from 2006 to 2013.
Directory of Open Access Journals (Sweden)
Hui Zhao
Full Text Available Road traffic can play an important role in strengthening regional economic activities, especially at high altitude, and it is necessary to know important traffic-related information. Although previous studies reported on road traffic in China, there has been little research on high-altitude road traffic to date.The annual official census of road traffic safety from 2006 to 2013 was used to obtain data on the general population, registered drivers, registered vehicles, newly built roads, road traffic accidents (RTAs, mortality rate per 100 000 populations and per 10 000 vehicles in high-altitude provinces, including Tibet, Qinghai, Xinjiang, Gansu, Yunnan, Sichuan, and Chongqing. These provincial data were reviewed retrospectively, with the national data as the reference. Statistical analysis (i.e., t test was used to compare the estimated average annual change rate of population, number of registered drivers, registered vehicles, and newly built roads in high-altitude provinces with the national rates.Compared with the national data, there are significantly higher annual rates of population growth in Tibet and Xinjiang, registered drivers in Gansu, registered vehicles in Gansu, Sichuan, and Chongqing, and newly built roads in Tibet and Qinghai. Among the investigated provinces, Tibet, Qinghai, and Yunnan had a higher proportion of the roads with the high class. RTAs and RTA-induced casualties in the high-altitude provinces indicated a decreasing trend. The mortality rate per 10 000 vehicles and per 100 000 populations showed a decreasing trend, while the RTA-related mortality rate in Tibet, Qinghai, Xinjiang and Gansu remained high.Major changes for road traffic in high-altitude provinces have occurred over the past decade; however, the RTA-related mortality rate in high-altitude provinces has remained high. This study furthers understanding about road traffic safety in China; further studies on road traffic safety at high altitude should be
The Path Taken: Consequences of Attaining Intrinsic and Extrinsic Aspirations in Post-College Life.
Niemiec, Christopher P; Ryan, Richard M; Deci, Edward L
2009-06-01
Life goals, or aspirations, organize and direct behavior over extended periods of time. The present study, guided by self-determination theory, examined the consequences of pursuing and attaining aspirations over a one-year period in a post-college sample. Results indicated that placing importance on either intrinsic or extrinsic aspirations related positively to attainment of those goals. Yet, whereas attainment of intrinsic aspirations related positively to psychological health, attainment of extrinsic aspirations did not; indeed, attainment of extrinsic aspirations related positively to indicators of ill-being. Also as predicted, the association between change in attainment of intrinsic aspirations and change in psychological health was mediated by change in the satisfaction of the basic psychological needs for autonomy, competence, and relatedness. Discussion focuses on the idea that not all goal attainment is beneficial; rather, attainment of aspirations with different contents relates differentially to psychological health.
Güvenç, Tolga Sinan; Erer, Hatice Betül; Kul, Seref; Perinçek, Gökhan; Ilhan, Sami; Sayar, Nurten; Yıldırım, Binnaz Zeynep; Doğan, Coşkun; Karabağ, Yavuz; Balcı, Bahattin; Eren, Mehmet
2013-01-01
Pulmonary vasculature is affected in patients with chronic pulmonary obstructive disease (COPD). As a result of increased pulmonary resistance, right ventricular morphology and function are altered in COPD patients. High altitude and related hypoxia causes pulmonary vasoconstriction, thereby affecting the right ventricle. We aimed to investigate the combined effects of COPD and altitude-related chronic hypoxia on right ventricular morphology and function. Forty COPD patients living at high altitude (1768 m) and 41 COPD patients living at sea level were enrolled in the study. All participants were diagnosed as COPD by a pulmonary diseases specialist depending on symptoms, radiologic findings and pulmonary function test results. Detailed two-dimensional echocardiography was performed by a cardiologist at both study locations. Oxygen saturation and mean pulmonary artery pressure were higher in the high altitude group. Right ventricular end diastolic diameter, end systolic diameter, height and end systolic area were significantly higher in the high altitude group compared to the sea level group. Parameters of systolic function, including tricuspid annular systolic excursion, systolic velocity of tricuspid annulus and right ventricular isovolumic acceleration were similar between groups, while fractional area change was significantly higher in the sea level groups compared to the high altitude group. Indices of diastolic function and myocardial performance index were similar between groups. An increase in mean pulmonary artery pressure and right ventricular dimensions are observed in COPD patients living at high altitude. Despite this increase, systolic and diastolic functions of the right ventricle, as well as global right ventricular performance are similar in COPD patients living at high altitude and sea level. Altitude-related adaptation to chronic hypoxia could explain these findings. Copyright © 2012 Australian and New Zealand Society of Cardiac and Thoracic
Long term picoplankton dynamics in a warm-monomictic, tropical high altitude lake
Directory of Open Access Journals (Sweden)
Alfonso LUGO VÁZQUEZ
2009-08-01
Full Text Available Long term analyses of the microbial loop, centred on the picoplankton dynamics, were carried out over a five-year (1998 to 2002 period in Lake Alchichica (Puebla, Mexico, a high altitude tropical athalassohaline lake. The hydrodynamics of the lake followed a warm-monomictic pattern with mixing at a minimum temperature during the early dry season while the stratification was pronounced in the late dry season and throughout the rainy season; anoxic conditions in the hypolimnion lasted <9 months. The annual mean concentrations of chlorophyll-a were below 4 μg L-1 in 1998, 1999 and 2001, however, 6.1 and 5.2 μg L-1 in 2000 and 2002, respectively. Total picoplankton, TPP, displayed a temporal pattern that followed the mixing-stratification cycle. The highest TPP values (the whole water column ≥5×106 cells mL-1 were found during mixing and early stratification (January-March. The minimum numbers were present during late stratification (October-November. The maximum TPP numbers were observed within the layer 0-20 m, which corresponded to the epilimnion during the stratification period. Neither the thermocline nor the deep chlorophyll maximum showed an elevated TPP concentration. In the hypolimnion, TPP numbers were low (frequently <1×106 cells mL-1 apparently as a result of the long period of anoxia. Notwithstanding autotrophic picoplankton (APP contributed even ≥30% of TPP (2001 to 2002; no significant correlation was found between TPP and chlorophyll-a.
Pulmonary decompression sickness at altitude: early symptoms and circulating gas emboli
Balldin, Ulf I.; Pilmanis, Andrew A.; Webb, James T.
2002-01-01
INTRODUCTION: Pulmonary altitude decompression sickness (DCS) is a rare condition. 'Chokes' which are characterized by the triad of substernal pain, cough, and dyspnea, are considered to be associated with severe accumulation of gas bubbles in the pulmonary capillaries and may rapidly develop into a life-threatening medical emergency. This study was aimed at characterizing early symptomatology and the appearance of venous gas emboli (VGE). METHODS: Symptoms of simulated-altitude DCS and VGE (with echo-imaging ultrasound) were analyzed in 468 subjects who participated in 22 high altitude hypobaric chamber research protocols from 1983 to 2001 at Brooks Air Force Base, TX. RESULTS: Of 2525 subject-exposures to simulated altitude, 1030 (41%) had symptoms of DCS. Only 29 of those included DCS-related pulmonary symptoms. Of these, only 3 subjects had all three pulmonary symptoms of chokes; 9 subjects had two of the pulmonary symptoms; and 17 subjects had only one. Of the 29 subject-exposures with pulmonary symptoms, 27 had VGE and 21 had severe VGE. The mean onset times of VGE and symptoms in the 29 subject-exposures were 42 +/- 30 min and 109 +/- 61 min, respectively. In 15 subjects, the symptoms disappeared during recompression to ground level followed by 2 h of oxygen breathing. In the remaining 14 cases, the symptoms disappeared with immediate hyperbaric oxygen treatment. CONCLUSIONS: Pulmonary altitude DCS or chokes is confirmed to be a rare condition. Our data showed that when diagnosed early, recompression to ground level pressure and/or hyperbaric oxygen treatment was 100% successful in resolving the symptoms.
The Laddermill : Innovative Wind Energy from High Altitudes in Holland and Australia
Lansdorp, B.; Williams, P.
2006-01-01
The Laddermill is a novel concept to harvest electricity from high altitude winds. The concept's operating principle is to drive an electric generator using tethered kites. Several kites are deployed to altitudes of more than 1 km by means of a single cable that is connected to a drum on the
Closing the Attainment Gap--A Realistic Proposition or an Elusive Pipe-Dream?
Mowat, Joan Gaynor
2018-01-01
The attainment gap associated with socio-economic status is an international problem that is highly resistant to change. This conceptual paper critiques the drive by the Scottish Government to address the attainment gap through the Scottish Attainment Challenge and the National Improvement Framework. It draws upon a range of theoretical…
Functions and Design Scheme of Tibet High Altitude Test Base
Institute of Scientific and Technical Information of China (English)
Yu Yongqing; Guo Jian; Yin Yu; Mao Yan; Li Guangfan; Fan Jianbin; Lu Jiayu; Su Zhiyi; Li Peng; Li Qingfeng; Liao Weiming; Zhou Jun
2010-01-01
@@ The functional orientation of the Tibet High Altitude Test Base, subordinated to the State Grid Corporation of China (SGCC), is to serve power transmission projects in high altitude areas, especially to provide technical support for southwestern hydropower delivery projects by UHVDC transmission and Qinghai-Tibet grid interconnection project. This paper presents the matters concerned during siting and planning, functions,design scheme, the main performances and parameters of the test facilities, as well as the tests and research tasks already carried out.
Energy management strategy for solar-powered high-altitude long-endurance aircraft
International Nuclear Information System (INIS)
Gao, Xian-Zhong; Hou, Zhong-Xi; Guo, Zheng; Liu, Jian-Xia; Chen, Xiao-Qian
2013-01-01
Highlights: ► A new Energy Management Strategy (EMS) for high-altitude solar-powered aircraft is purposed. ► The simulations show that the aircraft can always keep the altitude above 16 km with the proposed EMS. ► The proposed EMS is capable to alleviate the power consumed for aircraft during night. ► The main technologies to improve the flight performance of aircraft are analyzed. - Abstract: Development of solar-powered High-Altitude Long-Endurance (HALE) aircraft has a great impact on both military and civil aviation industries since its features in high-altitude and energy source can be considered inexhaustible. Owing to the development constraints of rechargeable batteries, the solar-powered HALE aircraft must take amount of rechargeable batteries to fulfill the energy requirement in night, which greatly limits the operation altitude of aircraft. In order to solve this problem, a new Energy Management Strategy (EMS) is proposed based on the idea that the solar energy can be partly stored in gravitational potential in daytime. The flight path of HALE aircraft is divided into three stages. During the stage 1, the solar energy is stored in both lithium–sulfur battery and gravitational potential. The gravitational potential is released in stage 2 by gravitational gliding and the required power in stage 3 is supplied by lithium–sulfur battery. Correspondingly, the EMS is designed for each stage. The simulation results show that the aircraft can always keep the altitude above 16 km with the proposed EMS, and the power consumed during night can be also alleviated. Comparing with the current EMS, about 23.5% energy is remained in batteries with the proposed EMS during one day–night cycle. The sensitivities of the improvement of crucial technologies to the performance of aircraft are also analyzed. The results show that the enhancement of control and structural system, lithium–sulfur battery, and solar cell are ranked in descending order for the
Goal conflicts, attainment of new goals, and well-being among managers.
Kehr, Hugo M
2003-07-01
Researchers widely understand that conflicts among goals inhibit the attainment of these goals. However, this notion comes close to tautological reasoning. To avert this problem, this study examined whether preexisting goal conflict also inhibits success in newly set goals. Using the context of management training, in which managers collectively set new goals, the study variables were assessed at 3 testing periods covering 5 months. Results indicate that goal conflicts that persevere over time were associated with inhibited attainment of new goals but not with decreased subjective well-being (SWB). Goal attainment, however, was positively related to SWB. Interactions of residual changes in goal conflict and goal attainment were associated with positive affect.
A Minimum Variance Algorithm for Overdetermined TOA Equations with an Altitude Constraint.
Energy Technology Data Exchange (ETDEWEB)
Romero, Louis A; Mason, John J.
2018-04-01
We present a direct (non-iterative) method for solving for the location of a radio frequency (RF) emitter, or an RF navigation receiver, using four or more time of arrival (TOA) measurements and an assumed altitude above an ellipsoidal earth. Both the emitter tracking problem and the navigation application are governed by the same equations, but with slightly different interpreta- tions of several variables. We treat the assumed altitude as a soft constraint, with a specified noise level, just as the TOA measurements are handled, with their respective noise levels. With 4 or more TOA measurements and the assumed altitude, the problem is overdetermined and is solved in the weighted least squares sense for the 4 unknowns, the 3-dimensional position and time. We call the new technique the TAQMV (TOA Altitude Quartic Minimum Variance) algorithm, and it achieves the minimum possible error variance for given levels of TOA and altitude estimate noise. The method algebraically produces four solutions, the least-squares solution, and potentially three other low residual solutions, if they exist. In the lightly overdermined cases where multiple local minima in the residual error surface are more likely to occur, this algebraic approach can produce all of the minima even when an iterative approach fails to converge. Algorithm performance in terms of solution error variance and divergence rate for bas eline (iterative) and proposed approach are given in tables.
Garvican, L; Martin, D; Quod, M; Stephens, B; Sassi, A; Gore, C
2012-02-01
To determine the time course of hemoglobin mass (Hb(mass)) to natural altitude training, Hb(mass), erythropoietin [EPO], reticulocytes, ferritin and soluble transferrin receptor (sTfR) were measured in 13 elite cyclists during, and 10 days after, 3 weeks of sea level (n=5) or altitude (n=8, 2760 m) training. Mean Hb(mass), with a typical error of ∼2%, increased during the first 11 days at altitude (mean ± standard deviation 2.9 ± 2.0%) and was 3.5 ± 2.5% higher than baseline after 19 days. [EPO] increased 64.2 ± 18.8% after 2 nights at altitude but was not different from baseline after 12 nights. Hb(mass) and [EPO] did not increase in sea level. Reticulocytes (%) were slightly elevated in altitude at Days 5 and 12 (18.9 ± 17.7% and 20.4 ± 25.3%), sTfR was elevated at Day 12 (18.9 ± 15.0%), but both returned to baseline by Day 20. Hb(mass) and [EPO] decreased on descent to sea level while ferritin increased. The mean increase in Hb(mass) observed after 11 days (∼300 h) of altitude training was beyond the measurement error and consitent with the mean increase after 300 h of simulated live high:train low altitude. Our results suggest that in elite cyclists, Hb(mass) increases progressively with 3 weeks of natural altitude exposure, with greater increases expected as exposure persists. © 2010 John Wiley & Sons A/S.
Climate Change Impacts on High-Altitude Ecosystems
Harald Pauli
2016-01-01
Reviewed: Climate Change Impacts on High-Altitude Ecosystems By Münir Öztürk, Khalid Rehman Hakeem, I. Faridah-Hanum and Efe. Recep, Cham, Switzerland: Springer International Publishing, 2015. xvii + 696 pp. US$ 239.00. ISBN 978-3-319-12858-0.
Mitaroff, Angela
2002-01-01
A reference facility for the calibration and intercomparison of active and passive detectors in broad neutron fields has been available at CERN since 1992. A positively charged hadron beam (a mixture of protons and pions) with momentum of 120 GeV/c hits a copper target, 50 cm thick and 7 cut in diameter. The secondary particles produced in the interaction traverse a shield, at 90 degrees with respect to the direction of the incoming beam, made of either 80 to 160 cm of concrete or 40 cm of iron. Behind the iron shield, the resulting neutron spectrum has a maximum at about 1 MeV, with an additional high-energy component. Behind the 80 cm concrete shield, the neutron spectrum has a second pronounced maximum at about 70 MeV and resembles the high-energy component of the radiation field created by cosmic rays at commercial flight altitudes. This paper describes the facility, reports on the latest neutron spectral measurements, gives an overview of the most important experiments performed by the various collaborat...
The evolution of Titan's high-altitude aerosols under ultraviolet irradiation
Carrasco, Nathalie; Tigrine, Sarah; Gavilan, Lisseth; Nahon, Laurent; Gudipati, Murthy S.
2018-04-01
The Cassini-Huygens space mission revealed that Titan's thick brownish haze is initiated high in the atmosphere at an altitude of about 1,000 km, before a slow transportation down to the surface. Close to the surface, at altitudes below 130 km, the Huygens probe provided information on the chemical composition of the haze. So far, we have not had insights into the possible photochemical evolution of the aerosols making up the haze during their descent. Here, we address this atmospheric aerosol aging process, simulating in the laboratory how solar vacuum ultraviolet irradiation affects the aerosol optical properties as probed by infrared spectroscopy. An important evolution was found that could explain the apparent contradiction between the nitrogen-poor infrared spectroscopic signature observed by Cassini below 600 km of altitude in Titan's atmosphere and a high nitrogen content as measured by the aerosol collector and pyrolyser of the Huygens probe at the surface of Titan.
Makos, Michał; Dzierżek, Jan; Nitychoruk, Jerzy; Zreda, Marek
2014-07-01
During the Last Glacial Maximum (LGM), long valley glaciers developed on the northern and southern sides of the High Tatra Mountains, Poland and Slovakia. Chlorine-36 exposure dating of moraine boulders suggests two major phases of moraine stabilization, at 26-21 ka (LGM I - maximum) and at 18 ka (LGM II). The dates suggest a significantly earlier maximum advance on the southern side of the range. Reconstructing the geometry of four glaciers in the Sucha Woda, Pańszczyca, Mlynicka and Velicka valleys allowed determining their equilibrium-line altitudes (ELAs) at 1460, 1460, 1650 and 1700 m asl, respectively. Based on a positive degree-day model, the mass balance and climatic parameter anomaly (temperature and precipitation) has been constrained for LGM I advance. Modeling results indicate slightly different conditions between northern and southern slopes. The N-S ELA gradient finds confirmation in slightly higher temperature (at least 1 °C) or lower precipitation (15%) on the south-facing glaciers during LGM I. The precipitation distribution over the High Tatra Mountains indicates potentially different LGM atmospheric circulation than at the present day, with reduced northwesterly inflow and increased southerly and westerly inflows of moist air masses.
Avaliação dos efeitos da altitude sobre a visão Analysis of vision effects at altitude
Directory of Open Access Journals (Sweden)
Luiz Filipe de Albuquerque Alves
2008-10-01
Full Text Available Este trabalho de revisão bibliográfica é direcionado para a investigação dos efeitos da hipóxia da altitude sobre a visão. Pretende assim, ser uma contribuição na identificação dos sinais e sintomas presentes durante a exposição do aeronavegante às altas altitudes. O conhecimento sobre as características da atmosfera terrestre e o comportamento dos gases quando submetidos à variação de pressão atmosférica são muito importantes para o correto diagnóstico dos disbarismos, hipóxia e doença da descompressão para os profissionais de saúde voltados para a atividade aeroespacial. O ambiente atmosférico a que os aeronavegantes são expostos, é capaz de interferir de forma significativa na função visual, podendo gerar lesões de caráter reversíveis ou não, tais como: hemorragias retinianas, diminuição da visão noturna e da acuidade visual, restrição do campo visual, aparecimento de estrabismos latentes, diminuição da pressão intra-ocular e alterações refracionais em indivíduos previamente submetidos às cirurgias refrativas.This bibliographic review work is pointed to the effects of altitude hypoxia on sight. It intends to contribute for the identification of signs and symptoms of hypoxia during high altitude exposition. The understanding of the terrestrial atmosphere and the laws of physics related to gas behavior under atmospheric pressure variation are very important for the correct diagnosis of the dysbarisms, hypoxia, decompression disease and others, by the aerospace health professionals. The atmospheric environment that pilots are exposed is able to interfere in a significant way on visual function and can lead to reversible or irreversible lesions such as: retinal bleeding, decrease of the night vision and vision acuity, restriction of the visual field, emergence of latent strabismus, decrease of the intra-ocular pressure and refractive alterations in individuals that went through refractive surgery.
Tong, Fuchun; Jin, Zhedong; Wang, Qingli; Xiao, Yihua
2003-10-01
The co-occurrence of soil fauna communities at different altitudes may reflect at some extent the relationships among communities, their coexistence, and the replacement of species along the altitude gradient. The continuous or disjunctive distribution of different species along altitude gradient not only reflected the environment variation at altitude gradient, but also the biological and ecological spatiality as well as the adaptability of species. The northern slope of Changbai Moutain has not only a high diversity in soil fauna types and species, but also a high variation of diversity pattern along the altitude gradient, which is a perfect transect for the research of biodiversity and gradient patterns. From 550 m to 2,560 m on the northern slope of Changbai Mountain, twenty-two plots were investigated with an interval of 100 m in altitude. By using Jaccard index, the co-occurrence of soil fauna communities at different altitudes was analyzed. For the species of different life forms or for all the species as a whole, the co-occurrence of soil faunae between neighboring communities was the highest, except for that between different soil fauna types. The peak and valley values of the co-occurrence of soil fauna communities along altitude gradient were matched with their gradient patterns, and the co-occurrence of soil faunae at different layers or all of the soil fauna communities were decreased with increasing altitude difference.
Future changes over the Himalayas: Maximum and minimum temperature
Dimri, A. P.; Kumar, D.; Choudhary, A.; Maharana, P.
2018-03-01
An assessment of the projection of minimum and maximum air temperature over the Indian Himalayan region (IHR) from the COordinated Regional Climate Downscaling EXperiment- South Asia (hereafter, CORDEX-SA) regional climate model (RCM) experiments have been carried out under two different Representative Concentration Pathway (RCP) scenarios. The major aim of this study is to assess the probable future changes in the minimum and maximum climatology and its long-term trend under different RCPs along with the elevation dependent warming over the IHR. A number of statistical analysis such as changes in mean climatology, long-term spatial trend and probability distribution function are carried out to detect the signals of changes in climate. The study also tries to quantify the uncertainties associated with different model experiments and their ensemble in space, time and for different seasons. The model experiments and their ensemble show prominent cold bias over Himalayas for present climate. However, statistically significant higher warming rate (0.23-0.52 °C/decade) for both minimum and maximum air temperature (Tmin and Tmax) is observed for all the seasons under both RCPs. The rate of warming intensifies with the increase in the radiative forcing under a range of greenhouse gas scenarios starting from RCP4.5 to RCP8.5. In addition to this, a wide range of spatial variability and disagreements in the magnitude of trend between different models describes the uncertainty associated with the model projections and scenarios. The projected rate of increase of Tmin may destabilize the snow formation at the higher altitudes in the northern and western parts of Himalayan region, while rising trend of Tmax over southern flank may effectively melt more snow cover. Such combined effect of rising trend of Tmin and Tmax may pose a potential threat to the glacial deposits. The overall trend of Diurnal temperature range (DTR) portrays increasing trend across entire area with
Education, the Process of Attainment and the Structure of Inequality. Discussion Papers #393-77.
Sorensen, Aage B.
This paper analyzes the properties of the process of social and economic attainments in two contrasting situations: (1) when the process of attainment generates the distribution of attainments, and (2) when the structure of attainments is seen as exogenously determined. It is argued that the neoclassical economic theory of earnings determination…
Climate Change Impacts on High-Altitude Ecosystems
Directory of Open Access Journals (Sweden)
Harald Pauli
2016-02-01
Full Text Available Reviewed: Climate Change Impacts on High-Altitude Ecosystems By Münir Öztürk, Khalid Rehman Hakeem, I. Faridah-Hanum and Efe. Recep, Cham, Switzerland: Springer International Publishing, 2015. xvii + 696 pp. US$ 239.00. ISBN 978-3-319-12858-0.
Differentiation of pulmonary embolism from high altitude pulmonary edema
International Nuclear Information System (INIS)
Khan, D.A.; Hashim, R.; Mirza, T.M.; Matloob-ur-Rehman, M.
2003-01-01
Objective: To differentiate the high altitude pulmonary edema (HAPE) from pulmonary embolism (PE) by clinical probability model of PE, lactate dehydrogenase (LDH), aspartate transaminase (AST) and D-dimer assays at high altitude. Subjects and Methods: Consecutive 40 patients evacuated from height > 3000 meters with symptoms of PE or HAPE were included. Clinical pretest probabilities scores of PE, Minutex D-dimer assay (Biopool international) and cardiac enzymes estimation by IFCC approved methods, were used for diagnosis. Mann-Whitney U test was applied by using SPSS and level of significance was taken at (p 500 ng/ml. Plasma D-dimer of 500 ng/ml was considered as cut-off value; 6(66.7%) patients of PE could be diagnosed and 30 (96.7%) cases of HAPE excluded indicating very good negative predictive value. Serum LDH, AST and CK were raised above the reference ranges in 8 (89%), 7 (78%) and 3 (33%) patients of PE as compared to 11 (35%), 6 (19%) and 9 (29%) of HAPE respectively. Conclusion: Clinical assessment in combination with D-dimer assay, LDH and AST can be used for timely differentiation of PE from HAPE at high altitude where diagnostic imaging procedures are not available. (author)
Genome-wide association study identifies 74 loci associated with educational attainment
DEFF Research Database (Denmark)
Okbay, Aysu; P. Beauchamp, Jonathan; Alan Fontana, Mark
2016-01-01
-nucleotide polymorphisms associated with educational attainment are disproportionately found in genomic regions regulating gene expression in the fetal brain. Candidate genes are preferentially expressed in neural tissue, especially during the prenatal period, and enriched for biological pathways involved in neural......Educational attainment is strongly influenced by social and other environmental factors, but genetic factors are estimated to account for at least 20% of the variation across individuals1. Here we report the results of a genome-wide association study (GWAS) for educational attainment that extends...... development. Our findings demonstrate that, even for a behavioural phenotype that is mostly environmentally determined, a well-powered GWAS identifies replicable associated genetic variants that suggest biologically relevant pathways. Because educational attainment is measured in large numbers of individuals...
Water-Vapor Raman Lidar System Reaches Higher Altitude
Leblanc, Thierry; McDermid, I. Stewart
2010-01-01
A Raman lidar system for measuring the vertical distribution of water vapor in the atmosphere is located at the Table Mountain Facility (TMF) in California. Raman lidar systems for obtaining vertical water-vapor profiles in the troposphere have been in use for some time. The TMF system incorporates a number of improvements over prior such systems that enable extension of the altitude range of measurements through the tropopause into the lower stratosphere. One major obstacle to extension of the altitude range is the fact that the mixing ratio of water vapor in the tropopause and the lower stratosphere is so low that Raman lidar measurements in this region are limited by noise. Therefore, the design of the TMF system incorporates several features intended to maximize the signal-to-noise ratio. These features include (1) the use of 355-nm-wavelength laser pulses having an energy (0.9 J per pulse) that is high relative to the laser-pulse energy levels of prior such systems, (2) a telescope having a large aperture (91 cm in diameter) and a narrow field of view (angular width .0.6 mrad), and (3) narrow-bandpass (wavelength bandwidth 0.6 nm) filters for the water-vapor Raman spectral channels. In addition to the large-aperture telescope, three telescopes having apertures 7.5 cm in diameter are used to collect returns from low altitudes.
Rare Particle Searches with the high altitude SLIM experiment
Balestra, S; Fabbri, F; Giacomelli, G; Giacomelli, R; Giorgini, M; Kumar, A; Manzoor, S; McDonald, J; Margiotta, A; Medinaceli, E; Nogales, J; Patrizii, L; Popa, V; Quereshi, I; Saavedra, O; Sher, G; Shahzad, M; Spurio, M; Ticona, R; Togo, V; Velarde, A; Zanini, A
2005-01-01
The search for rare particles in the cosmic radiation remains one of the main aims of non-accelerator particle astrophysics. Experiments at high altitude allow lower mass thresholds with respect to detectors at sea level or underground. The SLIM experiment is a large array of nuclear track detectors located at the Chacaltaya High Altitude Laboratory (5290 m a.s.l.). The preliminary results from the analysis of a part of the first 236 sq.m exposed for more than 3.6 y are here reported. The detector is sensitive to Intermediate Mass Magnetic Monopoles and to SQM nuggets and Q-balls, which are possible Dark Matter candidates.
McLean, Blake D; Buttifant, David; Gore, Christopher J; White, Kevin; Liess, Carsten; Kemp, Justin
2013-07-01
Little research has been done on the physiological and performance effects of altitude training on team-sport athletes. Therefore, this study examined changes in 2000-m time-trial running performance (TT), hemoglobin mass (Hbmass), and intramuscular carnosine content of elite Australian Football (AF) players after a preseason altitude camp. Thirty elite AF players completed 19 days of living and training at either moderate altitude (~2130 m; ALT, n = 21) or sea level (CON, n = 9). TT performance and Hbmass were assessed preintervention (PRE) and postintervention (POST1) in both groups and at 4 wk after returning to sea level (POST2) in ALT only. Improvement in TT performance after altitude was likely 1.5% (± 4.8-90%CL) greater in ALT than in CON, with an individual responsiveness of 0.8%. Improvements in TT were maintained at POST2 in ALT. Hbmass after altitude was very likely increased in ALT compared with CON (2.8% ± 3.5%), with an individual responsiveness of 1.3%. Hbmass returned to baseline at POST2. Intramuscular carnosine did not change in either gastrocnemius or soleus from PRE to POST1. A preseason altitude camp improved TT performance and Hbmass in elite AF players to a magnitude similar to that demonstrated by elite endurance athletes undertaking altitude training. The individual responsiveness of both TT and Hbmass was approximately half the group mean effect, indicating that most players gained benefit. The maintenance of running performance for 4 wk, despite Hbmass returning to baseline, suggests that altitude training is a valuable preparation for AF players leading into the competitive season.
Altitude control in honeybees: joint vision-based learning and guidance.
Portelli, Geoffrey; Serres, Julien R; Ruffier, Franck
2017-08-23
Studies on insects' visual guidance systems have shed little light on how learning contributes to insects' altitude control system. In this study, honeybees were trained to fly along a double-roofed tunnel after entering it near either the ceiling or the floor of the tunnel. The honeybees trained to hug the ceiling therefore encountered a sudden change in the tunnel configuration midways: i.e. a "dorsal ditch". Thus, the trained honeybees met a sudden increase in the distance to the ceiling, corresponding to a sudden strong change in the visual cues available in their dorsal field of view. Honeybees reacted by rising quickly and hugging the new, higher ceiling, keeping a similar forward speed, distance to the ceiling and dorsal optic flow to those observed during the training step; whereas bees trained to follow the floor kept on following the floor regardless of the change in the ceiling height. When trained honeybees entered the tunnel via the other entry (the lower or upper entry) to that used during the training step, they quickly changed their altitude and hugged the surface they had previously learned to follow. These findings clearly show that trained honeybees control their altitude based on visual cues memorized during training. The memorized visual cues generated by the surfaces followed form a complex optic flow pattern: trained honeybees may attempt to match the visual cues they perceive with this memorized optic flow pattern by controlling their altitude.
Kajian Teknologi High Altitude Platform (HAP [Study of High Altitude Platform (HAP Technology
Directory of Open Access Journals (Sweden)
Amry Daulat Gultom
2016-07-01
Full Text Available High Altitude Platform (HAP merupakan solusi alternatif untuk mengatasi keterbatasan infrastruktur terestrial maupun satelit. HAP merupakan pesawat ataupun balon udara yang ditempatkan pada ketinggian 20-50 km di atas permukaan bumi. Kelebihan yang utama dari HAP adalah kemudahan dalam penempatan, fleksibilitas, biaya operasionalnya rendah, delay propagasi rendah, sudut elevasi lebar, cakupan yang luas. Penelitian ini dilakukan untuk mengetahui potensi HAP untuk komunikasi pita lebar dan perkembangannya di Indonesia. Analisis dilakukan secara deskriptif dengan mengolah data literatur yang didapat. Hasil penelitian menunjukkan bahwa di Indonesia terdapat potensi teknologi HAP untuk komunikasi pita lebar dengan lebar pita 2x300 MHz di band 27,9-28,2 GHz dan 31-31,3 GHz. Namun, belum ada peraturan yang mengatur alokasi frekuensi untuk HAP secara khusus di Indonesia.*****High Altitude Platform (HAP has been developed as an alternative solution in order to overcome limitation of terrestrial and satellite communication system. HAP is an aircraft or balloon situated on 20-50 km above the earth. Main advantages of HAP are flexibility in deployment, low propagation delay, wide elevation angle and broad coverage. The research is conducted to gather HAP potential for broadband communication and its development in Indonesia. Analysis is conducted by descriptive analysis from literature study gather. The research result shows that in Indonesia, there is potential of HAP technology for broadband communication with 2x300 MHz bandwidth within 27,9-28,2 GHz and 31-31,3 GHz. Yet, there are no specific regulations managing frequency allocation for HAP in Indonesia.
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Heikki Mikael Karinen
2012-08-01
Full Text Available ObjectiveIf the body fails to acclimatize at high altitude, acute mountain sickness (AMS may result. For the early detection of AMS, changes in cardiac autonomic function measured by heart rate variability (HRV may be more sensitive than clinical symptoms alone. The purpose of this study was to ascertain if the changes in HRV during ascent are related to AMS.MethodsWe followed Lake Louise Score (LLS, arterial oxygen saturation at rest (R-SpO2 and exercise (Ex-SpO2 and HRV parameters daily in 36 different healthy climbers ascending from 2400 m to 6300 m altitudes during five different expeditions.ResultsAfter an ascent to 2400 m, standard deviation (RMSSD2 min, high-frequency power (HF2 min of HRV were 17-51 % and Ex-SpO2 was 3% lower in those climbers who suffered from AMS at 3000- 4300 m than in those only developing AMS later (≥ 5000 m or not at all (all p < 0.01. At the altitude of 2400 m RMSSD2 min ≤ 30 ms and Ex-SpO2 ≤ 91% both had 92% sensitivity for AMS if ascent continued without extra acclimatization days.ConclusionsChanges in supine HRV parameters at 2400 m were related to AMS at 3000-4300 m Thus, diverse analyses of HRV could offer potential markers for identifying the climbers at risk for AMS.
The impact of altitude on the sleep of young elite soccer players (ISA3600)
Sargent, Charli; 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; Roach, Gregory D
2013-01-01
Background Altitude training is used by elite athletes to improve sports performance, but it may also disrupt sleep. The aim of this study was to examine the effects of 2 weeks at high altitude on the sleep of young elite athletes. Methods Participants (n=10) were members of the Australian under-17 soccer team on an 18-day (19-night) training camp in Bolivia, with six nights at near sea level in Santa Cruz (430 m) and 13 nights at high altitude in La Paz (3600 m). Sleep was monitored using polysomnography during a baseline night at 430 m and three nights at 3600 m (immediately after ascent, 1 week after ascent and 2 weeks after ascent). Data were analysed using effect size statistics. Results All results are reported as comparisons with baseline. Rapid eye movement (REM) sleep was likely lower immediately upon ascent to altitude, possibly lower after 1 week and similar after 2 weeks. On all three nights at altitude, hypopneas and desaturations were almost certainly higher; oxygen saturation was almost certainly lower; and central apnoeas, respiratory arousals and periodic breathing were very likely higher. The effects on REM sleep were common to all but one participant, but the effects on breathing were specific to only half the participants. Conclusions The immediate effects of terrestrial altitude of 3600 m are to reduce the amount of REM sleep obtained by young elite athletes, and to cause 50% of them to have impaired breathing during sleep. REM sleep returns to normal after 2 weeks at altitude, but impaired breathing does not improve. PMID:24282215
All roads lead to Rome: the impact of multiple attainment means on motivation.
Huang, Szu-Chi; Zhang, Ying
2013-02-01
Individuals have different concerns before and after they become relatively certain about a goal's attainability; hence, we propose that the presence of alternative means of goal attainment will have a distinctive impact on motivation, depending on their stage of goal pursuit. In the initial stage of goal pursuit, people are concerned about whether the goal is attainable. The presence of multiple attainment means (vs. a single means) makes the goal seem more easily attainable and thus leads to greater motivation. Conversely, when people have made substantial progress on the goal and its attainment is relatively secured, they focus more on how they can race to the end and complete the pursuit. At these times, a single means (vs. multiple means) provides a more straightforward action plan and in turn leads to greater motivation. Two field studies and 3 lab experiments support this theorizing. (c) 2013 APA, all rights reserved.
Viticultura tropical a gran altitud. Condiciones y expresiones del terroir
Marco Quijano Rico
2009-01-01
Nuestro proyecto se inició en 1982 en la Loma de Puntalarga, entre 2500 y2600 metros de altitud, a 5,78 ºN y 72,98 ºW, en la cordillera oriental de los Andes. Las variedades más utilizadas actualmente son Pinot noir, Riesling y cruzamientos de Riesling x Silvaner. Desde 1984 se realizan trabajos de investigación sobre temas pertinentes. La baja latitud, la elevada altitud, el volumen de precipitación relativamente modesto y la transparencia del cielo, determinan el flujo de radiación solar in...
Mengembangkan Self Concept Siswa Melalui Model Pembelajaran Concept Attainment
Sumartini, Tina Sri
2015-01-01
Dalam pembelajaran matematika, siswa masih kurang memiliki self concept yang positif. Salah satu model pembelajaran yang dapat diterapkan untuk mengembangkan self concept siswa adalah model concept attainment. Tujuan penelitian ini adalah untuk mengetahui perkembangan self concept siswa setelah mendapatkan model pembelajaran concept attainment. Penelitian ini berbentuk one shot case study. Populasi dalam penelitian ini adalah siswa di salah satu SMK di Kabupaten Garut. Pengambilan sampel d...
A Clinician Guide to Altitude Training for Optimal Endurance Exercise Performance at Sea Level.
Constantini, Keren; Wilhite, Daniel P; Chapman, Robert F
2017-06-01
Constantini, Keren, Daniel P. Wilhite, and Robert F. Chapman. A clinician guide to altitude training for optimal endurance exercise performance at sea level. High Alt Med Biol. 18:93-101, 2017.-For well over 50 years, endurance athletes have been utilizing altitude training in an effort to enhance performance in sea level competition. This brief review will offer the clinician a series of evidence-based best-practice guidelines on prealtitude and altitude training considerations, which can ultimately maximize performance improvement outcomes.
Aero-thermo-dynamic analysis of the Spaceliner-7.1 vehicle in high altitude flight
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.
Energy Technology Data Exchange (ETDEWEB)
Salama, Samir A., E-mail: salama.3@buckeyemail.osu.edu [High Altitude Research Center, Taif University, Al-Haweiah, Taif 21974 (Saudi Arabia); Department of Biochemistry, Faculty of Pharmacy, Al-Azhar University, Cairo 11751 (Egypt); Department of Pharmacology and GTMR Unit, College of Clinical Pharmacy, Taif University, Al-Haweiah, Taif 21974 (Saudi Arabia); Omar, Hany A. [Department of Pharmacology, Faculty of Pharmacy, Beni-Suef University, Beni-Suef 62514 (Egypt); Maghrabi, Ibrahim A. [Department of Clinical Pharmacy, College of Clinical Pharmacy, Taif University, Al-Haweiah, Taif 21974 (Saudi Arabia); AlSaeed, Mohammed S. [Department of Surgery, College of Medicine, Taif University, Al-Haweiah, Taif 21974 (Saudi Arabia); EL-Tarras, Adel E. [High Altitude Research Center, Taif University, Al-Haweiah, Taif 21974 (Saudi Arabia)
2014-01-01
Exposure to high altitudes is associated with hypoxia and increased vulnerability to oxidative stress. Polycythemia (increased number of circulating erythrocytes) develops to compensate the high altitude associated hypoxia. Iron supplementation is, thus, recommended to meet the demand for the physiological polycythemia. Iron is a major player in redox reactions and may exacerbate the high altitudes-associated oxidative stress. The aim of this study was to explore the potential iron-induced oxidative lung tissue injury in rats at high altitudes (6000 ft above the sea level). Iron supplementation (2 mg elemental iron/kg, once daily for 15 days) induced histopathological changes to lung tissues that include severe congestion, dilatation of the blood vessels, emphysema in the air alveoli, and peribronchial inflammatory cell infiltration. The levels of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α), lipid peroxidation product and protein carbonyl content in lung tissues were significantly elevated. Moreover, the levels of reduced glutathione and total antioxidant capacity were significantly reduced. Co-administration of trolox, a water soluble vitamin E analog (25 mg/kg, once daily for the last 7 days of iron supplementation), alleviated the lung histological impairments, significantly decreased the pro-inflammatory cytokines, and restored the oxidative stress markers. Together, our findings indicate that iron supplementation at high altitudes induces lung tissue injury in rats. This injury could be mediated through excessive production of reactive oxygen species and induction of inflammatory responses. The study highlights the tissue injury induced by iron supplementation at high altitudes and suggests the co-administration of antioxidants such as trolox as protective measures. - Highlights: • Iron supplementation at high altitudes induced lung histological changes in rats. • Iron induced oxidative stress in lung tissues of rats at high altitudes. • Iron
International Nuclear Information System (INIS)
Salama, Samir A.; Omar, Hany A.; Maghrabi, Ibrahim A.; AlSaeed, Mohammed S.; EL-Tarras, Adel E.
2014-01-01
Exposure to high altitudes is associated with hypoxia and increased vulnerability to oxidative stress. Polycythemia (increased number of circulating erythrocytes) develops to compensate the high altitude associated hypoxia. Iron supplementation is, thus, recommended to meet the demand for the physiological polycythemia. Iron is a major player in redox reactions and may exacerbate the high altitudes-associated oxidative stress. The aim of this study was to explore the potential iron-induced oxidative lung tissue injury in rats at high altitudes (6000 ft above the sea level). Iron supplementation (2 mg elemental iron/kg, once daily for 15 days) induced histopathological changes to lung tissues that include severe congestion, dilatation of the blood vessels, emphysema in the air alveoli, and peribronchial inflammatory cell infiltration. The levels of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α), lipid peroxidation product and protein carbonyl content in lung tissues were significantly elevated. Moreover, the levels of reduced glutathione and total antioxidant capacity were significantly reduced. Co-administration of trolox, a water soluble vitamin E analog (25 mg/kg, once daily for the last 7 days of iron supplementation), alleviated the lung histological impairments, significantly decreased the pro-inflammatory cytokines, and restored the oxidative stress markers. Together, our findings indicate that iron supplementation at high altitudes induces lung tissue injury in rats. This injury could be mediated through excessive production of reactive oxygen species and induction of inflammatory responses. The study highlights the tissue injury induced by iron supplementation at high altitudes and suggests the co-administration of antioxidants such as trolox as protective measures. - Highlights: • Iron supplementation at high altitudes induced lung histological changes in rats. • Iron induced oxidative stress in lung tissues of rats at high altitudes. • Iron
Heinicke, K; Heinicke, I; Schmidt, W; Wolfarth, B
2005-06-01
It is well known that altitude training stimulates erythropoiesis, but only few data are available concerning the direct altitude effect on red blood cell volume (RCV) in world class endurance athletes during exposure to continued hypoxia. The purpose of this study was to evaluate the impact of three weeks of traditional altitude training at 2050 m on total hemoglobin mass (tHb), RCV and erythropoietic activity in highly-trained endurance athletes. Total hemoglobin mass, RCV, plasma volume (PV), and blood volume (BV) from 6 males and 4 females, all members of a world class biathlon team, were determined on days 1 and 20 during their stay at altitude as well as 16 days after returning to sea-level conditions (800 m, only males) by using the CO-rebreathing method. In males tHb (14.0 +/- 0.2 to 15.3 +/- 1.0 g/kg, p altitude and returned to near sea-level values 16 days after descent. Similarly in females, tHb (13.0 +/- 1.0 to 14.2 +/- 1.3 g/kg, p altitude training period, whereas PV was not altered. In male athletes, plasma erythropoietin concentration increased up to day 4 at altitude (11.8 +/- 5.0 to 20.8 +/- 6.0 mU/ml, p altitude training period, both parameters indicating enhanced erythropoietic activity. In conclusion, we show for the first time that a three-week traditional altitude training increases erythropoietic activity even in world class endurance athletes leading to elevated tHb and RCV. Considering the relatively fast return of tHb and RCV to sea-level values after hypoxic exposure, our data suggest to precisely schedule training at altitude and competition at sea level.
Measurements of radioactive dust in high altitude air
International Nuclear Information System (INIS)
Kobayashi, Mika; Kohara, Eri; Muronoi, Naohiro; Masuda, Yousuke; Midou, Tomotaka; Ishida, Yukiko; Shimizu, Toshihiko; Saga, Minoru; Endo, Hiromu
2012-01-01
The radioactivity in samples of airborne dust was measured. The samples had been collected at high altitude by the Japan Air Self-Defense Force. The data were obtained for the gross beta activity, gamma nuclide determination and radiochemical analysis. It was shown that there was no appreciable difference between the activity levels obtained in this time and in the year before. Seasonal variations were not very pronounced. It was found that the radioactivity at high altitude had been stable at a low level. Radioactive gases (gaseous radioiodine and xenon gas) were not detected. This report does not include the result on radionuclide measurements that Technical Research and Development Institute executed for examining the nuclear emergency situation at Fukushima Daiichi and Daini nuclear power plants after Tohoku Region Pacific Ocean Earthquake on March 11, 2011. (author)
Attractiveness Compensates for Low Status Background in the Prediction of Educational Attainment.
Bauldry, Shawn; Shanahan, Michael J; Russo, Rosemary; Roberts, Brent W; Damian, Rodica
2016-01-01
People who are perceived as good looking or as having a pleasant personality enjoy many advantages, including higher educational attainment. This study examines (1) whether associations between physical/personality attractiveness and educational attainment vary by parental socioeconomic resources and (2) whether parental socioeconomic resources predict these forms of attractiveness. Based on the theory of resource substitution with structural amplification, we hypothesized that both types of attractiveness would have a stronger association with educational attainment for people from disadvantaged backgrounds (resource substitution), but also that people from disadvantaged backgrounds would be less likely to be perceived as attractive (amplification). This study draws on data from the National Longitudinal Study of Adolescent to Adult Health-including repeated interviewer ratings of respondents' attractiveness-and trait-state structural equation models to examine the moderation (substitution) and mediation (amplification) of physical and personality attractiveness in the link between parental socioeconomic resources and educational attainment. Both perceived personality and physical attractiveness have stronger associations with educational attainment for people from families with lower levels of parental education (substitution). Further, parental education and income are associated with both dimensions of perceived attractiveness, and personality attractiveness is positively associated with educational attainment (amplification). Results do not differ by sex and race/ethnicity. Further, associations between perceived attractiveness and educational attainment remain after accounting for unmeasured family-level confounders using a sibling fixed-effects model. Perceived attractiveness, particularly personality attractiveness, is a more important psychosocial resource for educational attainment for people from disadvantaged backgrounds than for people from advantaged
Directory of Open Access Journals (Sweden)
M. Höpfner
2013-10-01
Full Text Available We present a climatology of monthly and 10° zonal mean profiles of sulfur dioxide (SO2 volume mixing ratios (vmr derived from MIPAS/Envisat measurements in the altitude range 15–45 km from July 2002 until April 2012. The vertical resolution varies from 3.5–4 km in the lower stratosphere up to 6–10 km at the upper end of the profiles, with estimated total errors of 5–20 pptv for single profiles of SO2. Comparisons with the few available observations of SO2 up to high altitudes from ATMOS for a volcanically perturbed situation from ACE-FTS and, at the lowest altitudes, with stratospheric in situ observations reveal general consistency of the datasets. The observations are the first empirical confirmation of features of the stratospheric SO2 distribution, which have only been shown by models up to now: (1 the local maximum of SO2 at around 25–30 km altitude, which is explained by the conversion of carbonyl sulfide (COS as the precursor of the Junge layer; and (2 the downwelling of SO2-rich air to altitudes of 25–30 km at high latitudes during winter and its subsequent depletion on availability of sunlight. This has been proposed as the reason for the sudden appearance of enhanced concentrations of condensation nuclei during Arctic and Antarctic spring. Further, the strong increase of SO2 to values of 80–100 unit{pptv} in the upper stratosphere through photolysis of H2SO4 has been confirmed. Lower stratospheric variability of SO2 could mainly be explained by volcanic activity, and no hints of a strong anthropogenic influence have been found. Regression analysis revealed a QBO (quasi-biennial oscillation signal of the SO2 time series in the tropics at about 30–35 km, an SAO (semi-annual oscillation signal at tropical and subtropical latitudes above 32 km and annual periodics predominantly at high latitudes. Further, the analysis indicates a correlation with the solar cycle in the tropics and southern subtropics above 30 km
Úbeda, J.; Palacios, D.; Vázquez, L.
2009-04-01
The Nevado Coropuna (15°31'S-72°39'W) is a volcanic complex located 200 km NE of the city of Arequipa, in the Southern Peruvian Andes. The summit area in the complex is covered with a glacier system formed by dozens of branches descending in all directions totaling many km2 in surface area. The study of the volcanic complex and its glaciers is of great interest because it is the main water reserve for tens of thousands of people, because of the risk scenario created by the presence of ice masses on a volcano with relatively recent activity, and because it constitutes an excellent geoindicator of the effects of climate change on ice masses in the western mountain chain of the Central Andes. This research aims to analyze glacier evolution using as geoindicators variations in glacier surface and equilibrium line altitudes (ELAs), defining deglaciation rates based on those variations and preparing forecasts with them on when the ice masses might disappear if the same rates were to occur in the future. In addition, a first estimation is attempted of the chronologies of the last phase of volcanic activity and the last phase of maximum glacier advance that can be attributed to the Late Glacial or Last Glacial Maximum periods. To achieve these aims, digital topography with 50m contour interval, two orthophotos of the central section of the Coropuna complex (15-6-1955 and 21-10-1986), an ASTER satellite image (12-11-2007) and geomorphological mapping of the volcanic complex created in a previous phase of the research (Ubeda, 2007) were integrated into a Geographical Information System (GIS). The GIS was used to determine the global extent of the glacier system, and in more detail, that of two groups (NE and SE) in 1955, 1986 and 2007. Using the geomorphological cartography as a basis, the extent of the glaciers during their last advance in the Little Ice Age (LIA) and their last maximum advance were calculated. Next, surface areas for all phases were calculated using
Decompression tables for inside chamber attendants working at altitude.
Bell, James; Thombs, Paul A; Davison, William J; Weaver, Lindell K
2014-01-01
Hyperbaric oxygen (HBO2) multiplace chamber inside attendants (IAs) are at risk for decompression sickness (DCS). Standard decompression tables are formulated for sea-level use, not for use at altitude. At Presbyterian/St. Luke's Medical Center (Denver, Colorado, 5,924 feet above sea level) and Intermountain Medical Center (Murray, Utah, 4,500 feet), the decompression obligation for IAs is managed with U.S. Navy Standard Air Tables corrected for altitude, Bühlmann Tables, and the Nobendem© calculator. IAs also breathe supplemental oxygen while compressed. Presbyterian/St. Luke's (0.83 atmospheres absolute/atm abs) uses gauge pressure, uncorrected for altitude, at 45 feet of sea water (fsw) (2.2 atm abs) for routine wound care HBO2 and 66 fsw (2.8 atm abs) for carbon monoxide/cyanide poisoning. Presbyterian/St. Luke's provides oxygen breathing for the IAs at 2.2 atm abs. At Intermountain (0.86 atm abs), HBO2 is provided at 2.0 atm abs for routine treatments and 3.0 atm abs for carbon monoxide poisoning. Intermountain IAs breathe intermittent 50% nitrogen/50% oxygen at 3.0 atm abs and 100% oxygen at 2.0 atm abs. The chamber profiles include a safety stop. From 1990-2013, Presbyterian/St. Luke's had 26,900 total IA exposures: 25,991 at 45 fsw (2.2 atm abs) and 646 at 66 fsw (2.8 atm abs); there have been four cases of IA DCS. From 2008-2013, Intermountain had 1,847 IA exposures: 1,832 at 2 atm abs and 15 at 3 atm abs, with one case of IA DCS. At both facilities, DCS incidents occurred soon after the chambers were placed into service. Based on these results, chamber inside attendant risk for DCS at increased altitude is low when the inside attendants breathe supplemental oxygen.
On educational attainment in transition economies
Czech Academy of Sciences Publication Activity Database
Duczynski, Petr
2001-01-01
Roč. 10, č. 2 (2001), s. 163-173 ISSN 1210-0455 R&D Projects: GA AV ČR KSK9058117 Institutional research plan: CEZ:AV0Z7085904 Keywords : transition economies * educational attainment Subject RIV: AH - Economics
Signatures of electric fields from high and low altitude particle distributions
International Nuclear Information System (INIS)
Mizera, P.F.; Fennell, J.F.
1977-01-01
Measurements of high altitude (<1.3 R/sub e/) ions and electrons at auroral energies are used to provide evidence of parallel electric field acceleration over the dusk to midnight auroral regions for both the north and south hemispheres. The data, taken on August 12, 1976 by charged particle spectrometers on the S3-3 satellite, show evidence of potential differences of approx.2 kV below and approx.1 kV above a satellite altitude of 7300 km
Image Positioning Accuracy Analysis for Super Low Altitude Remote Sensing Satellites
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Ming Xu
2012-10-01
Full Text Available Super low altitude remote sensing satellites maintain lower flight altitudes by means of ion propulsion in order to improve image resolution and positioning accuracy. The use of engineering data in design for achieving image positioning accuracy is discussed in this paper based on the principles of the photogrammetry theory. The exact line-of-sight rebuilding of each detection element and this direction precisely intersecting with the Earth's elliptical when the camera on the satellite is imaging are both ensured by the combined design of key parameters. These parameters include: orbit determination accuracy, attitude determination accuracy, camera exposure time, accurately synchronizing the reception of ephemeris with attitude data, geometric calibration and precise orbit verification. Precise simulation calculations show that image positioning accuracy of super low altitude remote sensing satellites is not obviously improved. The attitude determination error of a satellite still restricts its positioning accuracy.
There is variability in the attainment of developmental milestones in the CDKL5 disorder.
Fehr, Stephanie; Leonard, Helen; Ho, Gladys; Williams, Simon; de Klerk, Nick; Forbes, David; Christodoulou, John; Downs, Jenny
2015-01-01
Individuals with the CDKL5 disorder have been described as having severely impaired development. A few individuals have been reported having attained more milestones including walking and running. Our aim was to investigate variation in attainment of developmental milestones and associations with underlying genotype. Data was sourced from the International CDKL5 Disorder Database, and individuals were included if they had a pathogenic or probably pathogenic CDKL5 mutation and information on early development. Kaplan-Meier time-to-event analyses investigated the occurrence of developmental milestones. Mutations were grouped by their structural/functional consequence, and Cox regression was used to investigate the relationship between genotype and milestone attainment. The study included 109 females and 18 males. By 5 years of age, only 75% of the females had attained independent sitting and 25% independent walking whilst a quarter of the males could sit independently by 1 year 3 months. Only one boy could walk independently. No clear relationship between mutation group and milestone attainment was present, although females with a late truncating mutation attained the most milestones. Attainment of developmental milestones is severely impaired in the CDKL5 disorder, with the majority who did attain skills attaining them at a late age. It appears as though males are more severely impaired than the females. Larger studies are needed to further investigate the role of genotype on clinical variability.
Directory of Open Access Journals (Sweden)
Kamila Płoszczyca
2018-04-01
Full Text Available Background: One of the goals of altitude training is to increase blood oxygen-carrying capacity in order to improve sea-level endurance performance in athletes. The elevated erythropoietin (EPO production in hypoxia is a key factor in the achievement of enhanced hematological variables. The level of the EPO increase and acceleration of erythropoiesis depend on the duration of exposure and degree of hypoxia. Furthermore, many other factors may affect the hematological response to altitude training.Aim: The purpose of this narrative review was to: (1 analyze the kinetics of EPO and hematological variables during and after altitude training; (2 summarize the current state of knowledge about the possible causes of individual or cohort differences in EPO and hematological response to altitude training; (3 formulate practical guidelines for athletes to improve the efficiency of altitude training.Methods: A narrative review was performed following an electronic search of the databases PubMed/MEDLINE and SPORTDiscus via EBSCO for all English-language articles published between 1997 and 2017.Results: Complete unification of results from studies on EPO kinetics was difficult due to different time and frequency of blood sampling by different researchers during and after altitude training, but the data presented in the reviewed literature allowed us to detect certain trends. The results of the reviewed studies were divergent and indicated either increase or no change of hematological variables following altitude training. Factors that may affect the hematological response to altitude training include hypoxic dose, training content, training background of athletes, and/or individual variability of EPO production.Conclusions: Despite the potential benefits arising from altitude training, its effectiveness in improving hematological variables is still debatable. Further research and better understanding of factors influencing the response to altitude, as well
Płoszczyca, Kamila; Langfort, Józef; Czuba, Miłosz
2018-01-01
Background: One of the goals of altitude training is to increase blood oxygen-carrying capacity in order to improve sea-level endurance performance in athletes. The elevated erythropoietin (EPO) production in hypoxia is a key factor in the achievement of enhanced hematological variables. The level of the EPO increase and acceleration of erythropoiesis depend on the duration of exposure and degree of hypoxia. Furthermore, many other factors may affect the hematological response to altitude training. Aim: The purpose of this narrative review was to: (1) analyze the kinetics of EPO and hematological variables during and after altitude training; (2) summarize the current state of knowledge about the possible causes of individual or cohort differences in EPO and hematological response to altitude training; (3) formulate practical guidelines for athletes to improve the efficiency of altitude training. Methods: A narrative review was performed following an electronic search of the databases PubMed/MEDLINE and SPORTDiscus via EBSCO for all English-language articles published between 1997 and 2017. Results: Complete unification of results from studies on EPO kinetics was difficult due to different time and frequency of blood sampling by different researchers during and after altitude training, but the data presented in the reviewed literature allowed us to detect certain trends. The results of the reviewed studies were divergent and indicated either increase or no change of hematological variables following altitude training. Factors that may affect the hematological response to altitude training include hypoxic dose, training content, training background of athletes, and/or individual variability of EPO production. Conclusions: Despite the potential benefits arising from altitude training, its effectiveness in improving hematological variables is still debatable. Further research and better understanding of factors influencing the response to altitude, as well as factors
Płoszczyca, Kamila; Langfort, Józef; Czuba, Miłosz
2018-01-01
Background: One of the goals of altitude training is to increase blood oxygen-carrying capacity in order to improve sea-level endurance performance in athletes. The elevated erythropoietin (EPO) production in hypoxia is a key factor in the achievement of enhanced hematological variables. The level of the EPO increase and acceleration of erythropoiesis depend on the duration of exposure and degree of hypoxia. Furthermore, many other factors may affect the hematological response to altitude training. Aim: The purpose of this narrative review was to: (1) analyze the kinetics of EPO and hematological variables during and after altitude training; (2) summarize the current state of knowledge about the possible causes of individual or cohort differences in EPO and hematological response to altitude training; (3) formulate practical guidelines for athletes to improve the efficiency of altitude training. Methods: A narrative review was performed following an electronic search of the databases PubMed/MEDLINE and SPORTDiscus via EBSCO for all English-language articles published between 1997 and 2017. Results: Complete unification of results from studies on EPO kinetics was difficult due to different time and frequency of blood sampling by different researchers during and after altitude training, but the data presented in the reviewed literature allowed us to detect certain trends. The results of the reviewed studies were divergent and indicated either increase or no change of hematological variables following altitude training. Factors that may affect the hematological response to altitude training include hypoxic dose, training content, training background of athletes, and/or individual variability of EPO production. Conclusions: Despite the potential benefits arising from altitude training, its effectiveness in improving hematological variables is still debatable. Further research and better understanding of factors influencing the response to altitude, as well as factors
Hyperbaric oxygen preconditioning protects against traumatic brain injury at high altitude.
Hu, S L; Hu, R; Li, F; Liu, Z; Xia, Y Z; Cui, G Y; Feng, H
2008-01-01
Recent studies have shown that preconditioning with hyperbaric oxygen (HBO) can reduce ischemic and hemorrhagic brain injury. We investigated effects of HBO preconditioning on traumatic brain injury (TBI) at high altitude and examined the role of matrix metalloproteinase-9 (MMP-9) in such protection. Rats were randomly divided into 3 groups: HBO preconditioning group (HBOP; n = 13), high-altitude group (HA; n = 13), and high-altitude sham operation group (HASO; n = 13). All groups were subjected to head trauma by weight-drop device, except for HASO group. HBOP rats received 5 sessions of HBO preconditioning (2.5 ATA, 100% oxygen, 1 h daily) and then were kept in hypobaric chamber at 0.6 ATA (to simulate pressure at 4000m altitude) for 3 days before operation. HA rats received control pretreatment (1 ATA, room air, 1 h daily), then followed the same procedures as HBOP group. HASO rats were subjected to skull opening only without brain injury. Twenty-four hours after TBI, 7 rats from each group were examined for neurological function and brain water content; 6 rats from each group were killed for analysis by H&E staining and immunohistochemistry. Neurological outcome in HBOP group (0.71 +/- 0.49) was better than HA group (1.57 +/- 0.53; p < 0.05). Preconditioning with HBO significantly reduced percentage of brain water content (86.24 +/- 0.52 vs. 84.60 +/- 0.37; p < 0.01). Brain morphology and structure seen by light microscopy was diminished in HA group, while fewer pathological injuries occurred in HBOP group. Compared to HA group, pretreatment with HBO significantly reduced the number of MMP-9-positive cells (92.25 +/- 8.85 vs. 74.42 +/- 6.27; p < 0.01). HBO preconditioning attenuates TBI in rats at high altitude. Decline in MMP-9 expression may contribute to HBO preconditioning-induced protection of brain tissue against TBI.
Guide to Altitude Decompression Sickness Research
2010-05-01
fitness flight gender growth helium hormone human hyperbaric hypobaric hypoxia incidence injury interface interruption intra in-vitro isobaric male...exposure in hypobaric chambers and, due to its omission of other training, was not adequate for any other use. The two items required prior to...were kept in the contractor lab. 3. Hypobaric exposure records (Research Chamber Flight Records, including AF Forms 361) were kept by Altitude and
Influence the Rubber Seed Type and Altitude on Characteristic of Seed, Oil and Biodiesel
Directory of Open Access Journals (Sweden)
Salni Salni
2017-06-01
Full Text Available This research studies the influence of the type of rubber seed that is superior and local, altitude plant in South Sumatra province to the characteristic of seed, oil and biodiesel (methyl ester. Rubber plants planted from local rubber seed by seeds seedlings and superior rubber seed by selected clones. In the study, rubber plants planted at a different altitude, namely in Banyuasin district (18 m above sea level, Prabumulih District (176 m above sea level and Lahat District (627 m above sea level. The results showed that the weight of the flour, the water content and ash content in the local rubber seeds larger than the superior rubber seed for all altitude, but oil content a large in the superior rubber seeds. The major of fatty acids in the rubber seed oil in all types and altitude are a linoleic acid with a different percentage except local rubber seed oil from Lahat district with the large percentage of octadecanoic acid. Free fatty acids in the oil from the superior seeds rubber of 13.897-15.494 % large than local rubber seed oil was found 9.786-10.399 % for all altitude. By esterification process using sulfuric acid catalyst, Free Fatty Acid (FFA can be reduced to ≤ 2 %. The methyl ester made from the transesterification process of rubber seed oil after esterification using methanol and sodium hydroxide as catalyst. Analysis of methyl esters includes cetane index, flash point, kinematic viscosity, carbon residue, density, moisture content, water and sediment content and distillation compared with SNI 7182 and ASTM 6751-02. The result indicated that the quality of methyl ester from superior rubber seed oil in the Banyuasin and Prabumulih district better than another methyl ester. The types of rubber seed altitude affect the characteristics of the seed, oil and methyl ester but the altitude are not significantly different. Keywords: rubber seed, type, altitude, oil, biodiesel Article History: Received March 21st 2017; Received in
Peripheral blood lymphocytes: a model for monitoring physiological adaptation to high altitude.
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.
76 FR 11675 - IFR Altitudes; Miscellaneous Amendments
2011-03-03
... action is needed because of changes occurring in the National Airspace System. These changes are designed... matters of flight safety and operational efficiency in the National Airspace System, are related to... RIVER, AK NDB BARTER ISLAND, AK NDB... 2000 From To MEA MAA Sec. 95.3000 Low Altitude RNAV Routes Sec...
Altitude, Orthocenter of a Triangle and Triangulation
Directory of Open Access Journals (Sweden)
Coghetto Roland
2016-03-01
Full Text Available We introduce the altitudes of a triangle (the cevians perpendicular to the opposite sides. Using the generalized Ceva’s Theorem, we prove the existence and uniqueness of the orthocenter of a triangle [7]. Finally, we formalize in Mizar [1] some formulas [2] to calculate distance using triangulation.
Energy and emissions characterization of an eco-efficient biomass cook stove at different altitudes
International Nuclear Information System (INIS)
Pérez-Bayer, Juan F.; Graciano-Bustamante, Diana S.; Gómez-Betancur, José A.
2013-01-01
Around 2.5 billion people depend on wood as their main fuel for heating and cooking.In this work is studied the effect of altitude (678 and 1976 meters above sea level) on energy performance and emissions of an improved wood stove under standardized cooking tests. The experiments were carried out under the Water Boiling (WBT) and Controlled Cooking (CCT) Tests. The efficiency decreased about 24 % with increasing altitude in WBT, and specific fuel consumption increased 27.3 % due to the air density changes. Regarding the controlled cooking test, the specific fuel consumption and specific emissions increased by 15.3 % and 16 %, respectively. It is highlighted that altitude significantly affects the 'Plancha' wood stove behavior. Specific emissions increased at higher altitudes, so it is necessary to redesign wood stoves according to their geographical location in order to optimize the cooking process. (author)
International Nuclear Information System (INIS)
Sato, Masayuki; Muraoka, Koji; Hozumi, Koki; Sanada, Yukihisa; Yamada, Tsutomu; Torii, Tatsuo
2017-01-01
This paper is concerned with the design problem of preview altitude controller for Unmanned Airplane for Radiation Monitoring System (UARMS) to improve its control performance. UARMS has been developed for radiation monitoring around Fukushima Dai-ichi nuclear power plant which spread radiation contaminant due to the huge tsunamis caused by the Great East Japan Earthquake. The monitoring area contains flat as well as mountain areas. The basic flight controller has been confirmed to have satisfactory performance with respect to altitude holding; however, the control performance for variable altitude commands is not sufficient for practical use in mountain areas. We therefore design preview altitude controller with only proportional gains by considering the practicality and the strong requirement of safety for UARMS. Control performance of the designed preview controller was evaluated by flight tests conducted around Fukushima Sky Park. (author)
High Altitude Warfare: The Kargil Conflict and the Future
National Research Council Canada - National Science Library
Acosta, Marcus
2003-01-01
The unique combination of thin air, freezing temperatures, and mountainous terrain that forms the high altitude environment has resisted advances in military technology for centuries, The emergence...
The Relationship of Educational Attainment with Pulmonary Emphysema and Airway Wall Thickness.
Gjerdevik, Miriam; Grydeland, Thomas B; Washko, George R; Coxson, Harvey O; Silverman, Edwin K; Gulsvik, Amund; Bakke, Per S
2015-06-01
Low educational attainment is a risk factor of chronic obstructive pulmonary disease (COPD). There is limited knowledge on the relationship between educational level and computed tomography measures of emphysema and airway wall thickness (AWT). We hypothesized that low educational attainment is associated with increased emphysema and AWT in ever-smokers with and without COPD. We included 462 and 485 ever-smokers with and without COPD in a cross-sectional study, aged 40-86 years. The sample was divided into groups reflecting educational attainment: primary, secondary, and university. We performed linear regression to examine associations between educational attainment and both emphysema and AWT separately for those with and without COPD. We adjusted for sex, age, smoking status, age of onset of smoking, pack-years, height, and body mass index. Compared with university education, in subjects with COPD, primary education was associated with a 68.1% (95% confidence interval = 14.2-147.6%; P = 0.01) relative increase in emphysema and secondary education was associated with a 50.6% (95% confidence interval = 5.7-114.6%; P = 0.02) relative increase. There was a nonsignificant trend toward an association between lower educational attainment and increased emphysema among those without COPD (P = 0.18), yet greater age appeared to modify this association (P = 0.01). We did not detect significant linear relationships between educational attainment and AWT in subjects with or without COPD. Lower educational attainment was associated with increased emphysema among adults with COPD. Among those without COPD, this association was more pronounced with increasing age. No significant linear relationship between educational attainment and AWT was found. Clinicians treating adults with emphysema should keep in mind that factors related to low education beyond that of smoking and occupational dust exposure might be of importance to the disease.
Dosimetric significance of cosmic radiation in the altitude of SST and in free space
Energy Technology Data Exchange (ETDEWEB)
Allkofer, O C [Kiel Univ. (Germany, F.R.). Inst. fuer Reine und Angewandte Kernphysik
1977-01-01
The integral cosmic-ray flux, and hence the dose rate, increases with altitude. At the cruising altitude of the subsonic jets, about 10 km, the dose rate is already about a factor 70 higher than at sea level. At the higher altitudes of SST the situation is different because the composition of the galactic component differs from that at the subsonic level, the solar flares are more efficient, and a small number of heavy nuclei are still present. In free space an additional radiation hazard appears when the radiation belts have to be crossed.
United States high-altitude test experiences. A review emphasizing the impact on the environment
International Nuclear Information System (INIS)
Hoerlin, H.
1976-06-01
The US high-altitude nuclear explosions of the 1955-1962 period are listed chronologically; dates, locations, and yields are given. The major physical phases of the interactions of the weapon outputs with the atmosphere are described, such as the formation of fireballs at the low high-altitudes and the partition of energies and their distribution over very large spaces at the higher high-altitudes. The effects of these explosions on the normal activities of populations and the protective measures taken are documented. Many scientific observations, together with their significance and values, are reviewed. 109 refs
DEFF Research Database (Denmark)
Jensen, Kurt; Höög, Martina; Willis, Sarah
2013-01-01
INTRODUCTION: The Olympic cross country skiing competitions in 2014 will be held in Sochi, Russia at an altitude of approximately 1500m. Although moderate, this altitude is known to reduce performance in highly trained endurance athletes. It is also known that individuals react differently during...... altitude exposure. The purpose of this study was to evaluate performance changes during and after three weeks of training in moderate altitude in elite skiers. METHOD: Four male and three female skiers were tested on a roller skiing treadmill using the classic technique at sea level (NORM1), after 3 and 20...... and the WVO2max decreased 8.9% and 9.1%, respectively (P0.05). In contrast, the average power output (322±87W) during the “all out” test increased 3.4±2.7% 10 days after the altitude training (P
Girard, Olivier; Amann, Markus; Aughey, Robert; Billaut, François; Bishop, David J; Bourdon, Pitre; Buchheit, Martin; Chapman, Robert; D'Hooghe, Michel; Garvican-Lewis, Laura A; Gore, Christopher J; Millet, Grégoire P; Roach, Gregory D; Sargent, Charli; Saunders, Philo U; Schmidt, Walter; Schumacher, Yorck O
2013-12-01
Despite the limited research on the effects of altitude (or hypoxic) training interventions on team-sport performance, players from all around the world engaged in these sports are now using altitude training more than ever before. In March 2013, an Altitude Training and Team Sports conference was held in Doha, Qatar, to establish a forum of research and practical insights into this rapidly growing field. A round-table meeting in which the panellists engaged in focused discussions concluded this conference. This has resulted in the present position statement, designed to highlight some key issues raised during the debates and to integrate the ideas into a shared conceptual framework. The present signposting document has been developed for use by support teams (coaches, performance scientists, physicians, strength and conditioning staff) and other professionals who have an interest in the practical application of altitude training for team sports. After more than four decades of research, there is still no consensus on the optimal strategies to elicit the best results from altitude training in a team-sport population. However, there are some recommended strategies discussed in this position statement to adopt for improving the acclimatisation process when training/competing at altitude and for potentially enhancing sea-level performance. It is our hope that this information will be intriguing, balanced and, more importantly, stimulating to the point that it promotes constructive discussion and serves as a guide for future research aimed at advancing the bourgeoning body of knowledge in the area of altitude training for team sports.
Girard, Olivier; Amann, Markus; Aughey, Robert; Billaut, François; Bishop, David J; Bourdon, Pitre; Buchheit, Martin; Chapman, Robert; D'Hooghe, Michel; Garvican-Lewis, Laura A; Gore, Christopher J; Millet, Grégoire P; Roach, Gregory D; Sargent, Charli; Saunders, Philo U; Schmidt, Walter; Schumacher, Yorck O
2013-01-01
Despite the limited research on the effects of altitude (or hypoxic) training interventions on team-sport performance, players from all around the world engaged in these sports are now using altitude training more than ever before. In March 2013, an Altitude Training and Team Sports conference was held in Doha, Qatar, to establish a forum of research and practical insights into this rapidly growing field. A round-table meeting in which the panellists engaged in focused discussions concluded this conference. This has resulted in the present position statement, designed to highlight some key issues raised during the debates and to integrate the ideas into a shared conceptual framework. The present signposting document has been developed for use by support teams (coaches, performance scientists, physicians, strength and conditioning staff) and other professionals who have an interest in the practical application of altitude training for team sports. After more than four decades of research, there is still no consensus on the optimal strategies to elicit the best results from altitude training in a team-sport population. However, there are some recommended strategies discussed in this position statement to adopt for improving the acclimatisation process when training/competing at altitude and for potentially enhancing sea-level performance. It is our hope that this information will be intriguing, balanced and, more importantly, stimulating to the point that it promotes constructive discussion and serves as a guide for future research aimed at advancing the bourgeoning body of knowledge in the area of altitude training for team sports. PMID:24282213
Natural Selection on Genes Related to Cardiovascular Health in High-Altitude Adapted Andeans.
Crawford, Jacob E; Amaru, Ricardo; Song, Jihyun; Julian, Colleen G; Racimo, Fernando; Cheng, Jade Yu; Guo, Xiuqing; Yao, Jie; Ambale-Venkatesh, Bharath; Lima, João A; Rotter, Jerome I; Stehlik, Josef; Moore, Lorna G; Prchal, Josef T; Nielsen, Rasmus
2017-11-02
The increase in red blood cell mass (polycythemia) due to the reduced oxygen availability (hypoxia) of residence at high altitude or other conditions is generally thought to be beneficial in terms of increasing tissue oxygen supply. However, the extreme polycythemia and accompanying increased mortality due to heart failure in chronic mountain sickness most likely reduces fitness. Tibetan highlanders have adapted to high altitude, possibly in part via the selection of genetic variants associated with reduced polycythemic response to hypoxia. In contrast, high-altitude-adapted Quechua- and Aymara-speaking inhabitants of the Andean Altiplano are not protected from high-altitude polycythemia in the same way, yet they exhibit other adaptive features for which the genetic underpinnings remain obscure. Here, we used whole-genome sequencing to scan high-altitude Andeans for signals of selection. The genes showing the strongest evidence of selection-including BRINP3, NOS2, and TBX5-are associated with cardiovascular development and function but are not in the response-to-hypoxia pathway. Using association mapping, we demonstrated that the haplotypes under selection are associated with phenotypic variations related to cardiovascular health. We hypothesize that selection in response to hypoxia in Andeans could have vascular effects and could serve to mitigate the deleterious effects of polycythemia rather than reduce polycythemia itself. Copyright © 2017. Published by Elsevier Inc.
Coca: High Altitude Remedy of the Ancient Incas.
Biondich, Amy Sue; Joslin, Jeremy D
2015-12-01
The use of coca leaf for medicinal purposes is a centuries-old tradition of the native peoples of South America. Coca products are thought by many laypersons to provide risk-free benefits to users participating in strenuous activities at high altitude. Physiologic studies of coca have increased understanding of its possible mechanism of action as well as its potential impact on high altitude activities. This present work explores the role of coca throughout the history of the Andean peoples and explores whether this ancient remedy has a place in modern medicine. A focused summary of research articles with particular relevance to the field of wilderness medicine is also included to better provide the reader with lessons not only from history but also from another culture. Copyright © 2015 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.
Analysis of the maximum discharge of karst springs
Bonacci, Ognjen
2001-07-01
Analyses are presented of the conditions that limit the discharge of some karst springs. The large number of springs studied show that, under conditions of extremely intense precipitation, a maximum value exists for the discharge of the main springs in a catchment, independent of catchment size and the amount of precipitation. Outflow modelling of karst-spring discharge is not easily generalized and schematized due to numerous specific characteristics of karst-flow systems. A detailed examination of the published data on four karst springs identified the possible reasons for the limitation on the maximum flow rate: (1) limited size of the karst conduit; (2) pressure flow; (3) intercatchment overflow; (4) overflow from the main spring-flow system to intermittent springs within the same catchment; (5) water storage in the zone above the karst aquifer or epikarstic zone of the catchment; and (6) factors such as climate, soil and vegetation cover, and altitude and geology of the catchment area. The phenomenon of limited maximum-discharge capacity of karst springs is not included in rainfall-runoff process modelling, which is probably one of the main reasons for the present poor quality of karst hydrological modelling. Résumé. Les conditions qui limitent le débit de certaines sources karstiques sont présentées. Un grand nombre de sources étudiées montrent que, sous certaines conditions de précipitations extrêmement intenses, il existe une valeur maximale pour le débit des sources principales d'un bassin, indépendante des dimensions de ce bassin et de la hauteur de précipitation. La modélisation des débits d'exhaure d'une source karstique n'est pas facilement généralisable, ni schématisable, à cause des nombreuses caractéristiques spécifiques des écoulements souterrains karstiques. Un examen détaillé des données publiées concernant quatre sources karstiques permet d'identifier les raisons possibles de la limitation de l'écoulement maximal: (1
Variation of the gravity acceleration with the latitude and altitude
Directory of Open Access Journals (Sweden)
Wilson Lopes
2009-01-01
Full Text Available The propose of this work is an equation for the module of the acceleration vector of the gravity, varying with the latitude and altitude. For this purpose, the following values of the gravity acceleration were used, at the sea level: in the equator, g0 = 9,7803 m/s2, and in the latitude of 450, gP = 9,8062 m/s2. The terrestrial profile were assumed as being a revolution ellipsoid, flattened in the poles, and the acceleration of the gravity varying with the altitude, at sea level, was considered dependent of the latitude too.
Educational attainment and obesity: A systematic review
Cohen, Alison K.; Rai, Manisha; Rehkopf, David H.; Abrams, Barbara
2013-01-01
Background Although previous systematic reviews considered the relationship between socioeconomic status and obesity, almost 200 peer-reviewed articles have been published since the last review on that topic, and this paper focuses specifically on education, which has different implications. Methods The authors systematically review the peer-reviewed literature from around the world considering the association between educational attainment and obesity. Databases from public health and medicine, education, psychology, economics, and other social sciences were searched, and articles published in English, French, Portuguese, and Spanish were included. Results This paper includes 289 articles that report on 410 populations in 91 countries. The relationship between educational attainment and obesity was modified by both gender and the country's economic development level: an inverse association was more common in studies of higher-income countries and a positive association was more common in lower-income countries, with stronger social patterning among women. Relatively few studies reported on lower-income countries, controlled for a comprehensive set of potential confounding variables, and/or attempted to assess causality through the use of quasi-experimental designs. Conclusions Future research should address these gaps to understand if the relationship between educational attainment and obesity may be causal, thus supporting education policy as a tool for obesity prevention. PMID:23889851
Magín Lapuerta; Octavio Armas; John R Agudelo; Carlos A Sánchez
2006-01-01
En este trabajo se estudia el efecto de la altitud sobre la potencia en motores de aspiración natural y turbosobrealimentados sin sistemas correctores, en función de la presión ambiental. La altitud sobre el nivel del mar tiene un notable efecto sobre la densidad del aire y su composición. Dado que los motores de combustión interna tienen sistemas de admisión y de inyección de combustible volumétricos, la altitud modifica el ciclo termodinámico de operación, y en consecuencia las prestaciones...
High altitude environmental monitoring: the SHARE project and CEOP-HE
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
Atmospheric Sampling of Aerosols to Stratospheric Altitudes using High Altitude Balloons
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
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.
Dietz, Robert O.; Kuenzig, John K.
1947-01-01
Investigations were conducted in the Cleveland altitude wind tunnel to determine the performance and operational characteristics of the 19B-2, 19B-8, and 19XS-1 turbojet engines. One objective was to determine the effect of altitude, flight Mach number, and tail-pipe-nozzle area on the performance characteristics of the six-stage and ten-stage axial-flow compressors of the 19B-8 and 19XB-1 engines, respectively, The data were obtained over a range of simulated altitudes and flight Mach numbers. At each simulated flight condition the engine was run over its full operable range of speeds. Performance characteristics of the 19B-8 and 19XB-1 compressors for the range of operation obtainable in the turboJet-engine installation are presented. Compressor characteristics are presented as functions of air flow corrected to sea-level conditions, compressor Mach number, and compressor load coefficient. For the range of compressor operation investigated, changes in Reynolds number had no measurable effect on the relations among compressor Mach number, corrected air flow, compressor load coefficient, compressor pressure ratio, and compressor efficiency. The operating lines for the 19B-8 compressor lay on the low-air-flow side of the region of maximum compressor efficiency; the 19B-8 compressor operated at higher average pressure coefficients per stage and produced a lower over-all pressure ratio than did the 19XB-1 compressor.
Lens autofluorescence is not increased at high altitude
DEFF Research Database (Denmark)
Kessel, Line; Kofoed, Peter Kristian; Zubieta-Calleja, Gustavo
2010-01-01
in Denmark. RESULTS: No significant differences in lens fluorescence or transmittance were found between Bolivian and Danish volunteers. CONCLUSION: Age-corrected lens fluorescence and transmittance were comparable for healthy participants living at high altitude near the equator and healthy volunteers...
Customized altitude-azimuth mount for a raster-scanning Fourier transform spectrometer
Durrenberger, Jed E.; Gutman, William M.; Gammill, Troy D.; Grover, Dennis H.
1996-10-01
Applications of the Army Research Laboratory Mobile Atmospheric Spectrometer Remote Sensing Rover required development of a customized computer-controlled mount to satisfy a variety of requirements within a limited budget. The payload was designed to operate atop a military electronics shelter mounted on a 4-wheel drive truck to be above most atmospheric ground turbulence. Pointing orientation in altitude is limited by constraints imposed by use of a liquid nitrogen detector Dewar in the spectrometer. Stepper motor drives and control system are compatible with existing custom software used with other instrumentation for controlled incremental raster stepping. The altitude axis passes close to the center of gravity of the complete payload to minimize load eccentricity and drive torque requirements. Dovetail fixture mounting enables quick service and fine adjustment of balance to minimize stepper/gearbox drive backlash through the limited orientation range in altitude. Initial applications to characterization of remote gas plumes have been successful.
Effects of erythrocyte infusion on VO2max at high altitude
DEFF Research Database (Denmark)
Young, Jette Feveile; Sawka, M N; Muza, S R
1996-01-01
This study investigated whether autologous erythrocyte infusion would ameliorate the decrement in maximal O2 uptake (VO2max) experienced by lowlanders when they ascend to high altitude. VO2max was measured in 16 men (treadmill running) at sea level (SL) and on the 1st (HA1) and 9th (HA9) days...... of high-altitude (4,300 m) residence. After VO2max was measured at SL, subjects were divided into two matched groups (n = 8). Twenty-four hours before ascent to high altitude, the experimental group received a 700-ml infusion of autologous erythrocytes and saline (42% hematocrit), whereas the control...... group received only saline. The VO2max of erythrocyte-infused [54 +/- 1 (SE) ml.kg-1.min-1] and control subjects (52 +/- 2 ml.kg-1.min-1) did not differ at SL before infusion. The decrement in VO2max on HA1 did not differ between groups, averaging 26% overall, despite higher (P
Directory of Open Access Journals (Sweden)
Howell Alison
2012-09-01
Full Text Available Abstract Background To clarify the extent and putative transmission zone of bovine fasciolosis on the slopes of Mount Elgon, Uganda, conjoint parasitological and malacological surveys, inclusive of inspection of animals at slaughter, were undertaken at increasing altitudes. Results A total of 239 cattle were sampled across eight locations ranging in elevation from 1112-2072 m. Faecal material was examined for presence of Fasciola eggs and sera were tested by ELISA for antibodies against Fasciola antigens. Bolstering this, 38 cattle at slaughter from 2 abattoir sites at 1150 m and 1947 m were inspected; in addition, wild buffalo stool (n = 10 opportunistically picked within Mount Elgon National Park (MENP at 3640 m was examined. By faecal egg detection, prevalence of Fasciola gigantica at low (1500 m altitude sites was 43.7% (95% CI 35.4-52.2 and 1.1% (95% CI 0.0-6.0, respectively, while by ELISA was much higher, low altitude - 77.9% (95% CI 69.7-85.4 and high altitude - 64.5% (95% CI 51.3-76.3. The decline in prevalence with increasing altitude was corroborated by abattoir sampling. Thirty seven aquatic habitats, ranging from 1139-3937 m in altitude were inspected for freshwater snails, 12 of which were within MENP. At lower altitudes, Lymnaea (Radix natalensis was common, and often abundant, but at higher altitudes became much rarer ceasing to be found above 1800 m. On the other hand, Lymnaea (Galba truncatula was found only at altitudes above 3000 m and within MENP alone. The snail identifications were confirmed by DNA analysis of the ribosomal 18S gene. Conclusions Active infections of F. gigantica in cattle are common in lower altitude settings but appear to diminish with increasing elevation. This is likely due to a growing paucity of intermediate hosts, specifically populations of L. natalensis for which a natural boundary of 1800 m appeared. Although F. hepatica was not encountered, the presence of several
Educational attainment, formal employment and contraceptives ...
African Journals Online (AJOL)
Based on this, the study examines educational attainment, formal employment and contraceptives practices among working women in Lagos State University. Survey design was adopted for the study. Using Stratified and simple random sampling techniques, quantitative data was gathered through the administration of ...
A statistical study of high-altitude electric fields measured on the Viking satellite
International Nuclear Information System (INIS)
Lindqvist, P.A.; Marklund, G.T.
1990-01-01
Characteristics of high-altitude data from the Viking electric field instrument are presented in a statistical study based on 109 Viking orbits. The study is focused in particular on the signatures of and relationships between various parameters measured by the electric field instrument, such as the parallel and transverse (to B) components of the electric field instrument, such as electric field variability. A major goal of the Viking mission was to investigate the occurrence and properties of parallel electric fields and their role in the auroral acceleration process. The results in this paper on the altitude distribution of the electric field variability confirm earlier findings on the distribution of small-scale electric fields and indicate the presence of parallel fields up to about 11,000 km altitude. The directly measured parallel electric field is also investigated in some detail. It is in general directed upward with an average value of 1 mV/m, but depends on, for example, altitude and plasma density. Possible sources of error in the measurement of the parallel field are also considered and accounted for
Syndrome of Acute Anxiety Among Marines After Recent Arrival at High Altitude
2014-05-01
Naval Health Research Center Syndrome of Acute Anxiety Among Marines After Recent Arrival at High Altitude Michael K. Sracic Darren Thomas...Allen Pate Jacob Norris Marc Norman, Jeffrey H. Gertsch Report No. 13-29 The views expressed in this article are those of the authors...MEDICINE, 179, 5:559, 2014 Syndrome of Acute Anxiety Among Marines After Recent Arrival at High Altitude LT Michael K. Sracic, MC USN*; LT Darren Thomas
Genome-wide association study identifies 74 loci associated with educational attainment
A. Okbay (Aysu); J.P. Beauchamp (Jonathan); Fontana, M.A. (Mark Alan); J.J. Lee (James J.); T.H. Pers (Tune); Rietveld, C.A. (Cornelius A.); P. Turley (Patrick); Chen, G.-B. (Guo-Bo); V. Emilsson (Valur); Meddens, S.F.W. (S. Fleur W.); Oskarsson, S. (Sven); Pickrell, J.K. (Joseph K.); Thom, K. (Kevin); Timshel, P. (Pascal); R. de Vlaming (Ronald); A. Abdellaoui (Abdel); T.S. Ahluwalia (Tarunveer Singh); J. Bacelis (Jonas); C. Baumbach (Clemens); Bjornsdottir, G. (Gyda); J.H. Brandsma (Johan); Pina Concas, M. (Maria); J. Derringer; Furlotte, N.A. (Nicholas A.); T.E. Galesloot (Tessel); S. Girotto; Gupta, R. (Richa); L.M. Hall (Leanne M.); S.E. Harris (Sarah); E. Hofer; Horikoshi, M. (Momoko); J.E. Huffman (Jennifer E.); Kaasik, K. (Kadri); I.-P. Kalafati (Ioanna-Panagiota); R. Karlsson (Robert); A. Kong (Augustine); J. Lahti (Jari); S.J. van der Lee (Sven); Deleeuw, C. (Christiaan); P.A. Lind (Penelope); Lindgren, K.-O. (Karl-Oskar); Liu, T. (Tian); M. Mangino (Massimo); J. Marten (Jonathan); E. Mihailov (Evelin); M. Miller (Mike); P.J. van der Most (Peter); C. Oldmeadow (Christopher); A. Payton (Antony); N. Pervjakova (Natalia); W.J. Peyrot (Wouter ); Qian, Y. (Yong); O. Raitakari (Olli); Rueedi, R. (Rico); Salvi, E. (Erika); Schmidt, B. (Börge); Schraut, K.E. (Katharina E.); Shi, J. (Jianxin); A.V. Smith (Albert Vernon); R.A. Poot (Raymond); B. St Pourcain (Beate); A. Teumer (Alexander); G. Thorleifsson (Gudmar); N. Verweij (Niek); D. Vuckovic (Dragana); Wellmann, J. (Juergen); H.J. Westra (Harm-Jan); Yang, J. (Jingyun); Zhao, W. (Wei); Zhu, Z. (Zhihong); B.Z. Alizadeh (Behrooz); N. Amin (Najaf); Bakshi, A. (Andrew); S.E. Baumeister (Sebastian); G. Biino (Ginevra); K. Bønnelykke (Klaus); P.A. Boyle (Patricia); H. Campbell (Harry); Cappuccio, F.P. (Francesco P.); G. Davies (Gail); J.E. de Neve (Jan-Emmanuel); P. Deloukas (Panagiotis); I. Demuth (Ilja); Ding, J. (Jun); Eibich, P. (Peter); Eisele, L. (Lewin); N. Eklund (Niina); D.M. Evans (David); J.D. Faul (Jessica D.); M.F. Feitosa (Mary Furlan); A.J. Forstner (Andreas); I. Gandin (Ilaria); Gunnarsson, B. (Bjarni); B.V. Halldorsson (Bjarni); T.B. Harris (Tamara); E.G. Holliday (Elizabeth); A.C. Heath (Andrew C.); L.J. Hocking; G. Homuth (Georg); M. Horan (Mike); J.J. Hottenga (Jouke Jan); P.L. de Jager (Philip); P.K. Joshi (Peter); A. Juqessur (Astanand); M. Kaakinen (Marika); M. Kähönen (Mika); S. Kanoni (Stavroula); Keltigangas-Järvinen, L. (Liisa); L.A.L.M. Kiemeney (Bart); I. Kolcic (Ivana); Koskinen, S. (Seppo); A. Kraja (Aldi); Kroh, M. (Martin); Z. Kutalik (Zoltán); A. Latvala (Antti); L.J. Launer (Lenore); Lebreton, M.P. (Maël P.); D.F. Levinson (Douglas F.); P. Lichtenstein (Paul); P. Lichtner (Peter); D.C. Liewald (David C.); A. Loukola (Anu); P.A. Madden (Pamela); R. Mägi (Reedik); Mäki-Opas, T. (Tomi); R.E. Marioni (Riccardo); P. Marques-Vidal; Meddens, G.A. (Gerardus A.); G. Mcmahon (George); C. Meisinger (Christa); T. Meitinger (Thomas); Milaneschi, Y. (Yusplitri); L. Milani (Lili); G.W. Montgomery (Grant); R. Myhre (Ronny); C.P. Nelson (Christopher P.); D.R. Nyholt (Dale); W.E.R. Ollier (William); A. Palotie (Aarno); L. Paternoster (Lavinia); N.L. Pedersen (Nancy); K. Petrovic (Katja); D.J. Porteous (David J.); K. Räikkönen (Katri); Ring, S.M. (Susan M.); A. Robino (Antonietta); O. Rostapshova (Olga); I. Rudan (Igor); A. Rustichini (Aldo); V. Salomaa (Veikko); Sanders, A.R. (Alan R.); A.-P. Sarin; R. Schmidt (Reinhold); R.J. Scott (Rodney); B.H. Smith (Blair); J.A. Smith (Jennifer A); J.A. Staessen (Jan); E. Steinhagen-Thiessen (Elisabeth); K. Strauch (Konstantin); A. Terracciano; M.D. Tobin (Martin); S. Ulivi (Shelia); S. Vaccargiu (Simona); L. Quaye (Lydia); F.J.A. van Rooij (Frank); C. Venturini (Cristina); A.A.E. Vinkhuyzen (Anna A.); U. Völker (Uwe); Völzke, H. (Henry); J.M. Vonk (Judith); D. Vozzi (Diego); J. Waage (Johannes); E.B. Ware (Erin B.); G.A.H.M. Willemsen (Gonneke); J. Attia (John); D.A. Bennett (David A.); Berger, K. (Klaus); L. Bertram (Lars); H. Bisgaard (Hans); D.I. Boomsma (Dorret); I.B. Borecki (Ingrid); U. Bültmann (Ute); C.F. Chabris (Christopher F.); F. Cucca (Francesco); D. Cusi (Daniele); I.J. Deary (Ian J.); G.V. Dedoussis (George); C.M. van Duijn (Cornelia); K. Hagen (Knut); B. Franke (Barbara); L. Franke (Lude); P. Gasparini (Paolo); P.V. Gejman (Pablo); C. Gieger (Christian); H.J. Grabe (Hans Jörgen); J. Gratten (Jacob); P.J.F. Groenen (Patrick); V. Gudnason (Vilmundur); P. van der Harst (Pim); C. Hayward (Caroline); D.A. Hinds (David A.); W. Hoffmann (Wolfgang); E. Hypponen (Elina); W.G. Iacono (William); B. Jacobsson (Bo); M.-R. Jarvelin (Marjo-Riitta); K.-H. JöCkel (Karl-Heinz); J. Kaprio (Jaakko); S.L.R. Kardia (Sharon); T. Lehtimäki (Terho); Lehrer, S.F. (Steven F.); P.K. Magnusson (Patrik); N.G. Martin (Nicholas); M. McGue (Matt); A. Metspalu (Andres); N. Pendleton (Neil); B.W.J.H. Penninx (Brenda); M. Perola (Markus); N. Pirastu (Nicola); M. Pirastu (Mario); O. Polasek (Ozren); D. Posthuma (Danielle); C. Power (Christopher); M.A. Province (Mike); N.J. Samani (Nilesh); Schlessinger, D. (David); R. Schmidt (Reinhold); T.I.A. Sørensen (Thorkild); T.D. Spector (Timothy); J-A. Zwart (John-Anker); U. Thorsteinsdottir (Unnur); A.R. Thurik (Roy); Timpson, N.J. (Nicholas J.); H.W. Tiemeier (Henning); J.Y. Tung (Joyce Y.); A.G. Uitterlinden (André); Vitart, V. (Veronique); P. Vollenweider (Peter); D.R. Weir (David); J.F. Wilson (James F.); A.F. Wright (Alan); Conley, D.C. (Dalton C.); R.F. Krueger; G.D. Smith; Hofman, A. (Albert); D. Laibson (David); S.E. Medland (Sarah Elizabeth); M.N. Meyer (Michelle N.); J. Yang (Joanna); M. Johannesson (Magnus); P.M. Visscher (Peter); T. Esko (Tõnu); Ph.D. Koellinger (Philipp); D. Cesarini (David); D.J. Benjamin (Daniel J.)
2016-01-01
textabstractEducational attainment is strongly influenced by social and other environmental factors, but genetic factors are estimated to account for at least 20% of the variation across individuals. Here we report the results of a genome-wide association study (GWAS) for educational attainment that
Genome-wide association study identifies 74 loci associated with educational attainment
Okbay, A.; Beauchamp, J.; Fontana, M.A.; Lee, J.J.; Pers, T.H.; Rietveld, C.A.; Turley, P.; Chen, G.B.; Emilsson, V.; Meddens, S.F.W.; de Vlaming, R.; Abdellaoui, A.; Peyrot, W.; Vinkhuyzen, A.A.E.; Hottenga, J.J.; Willemsen, G.; Boomsma, D.I.; Penninx, B.W.J.H.; Laibson, D.; Medland, S.E.; Meyer, M.N.; Yang, J.; Johannesson, M.; Visscher, P.M.; Esko, T.; Koellinger, P.D.; Cesarini, D.; Benjamin, D.J.
2016-01-01
Educational attainment is strongly influenced by social and other environmental factors, but genetic factors are estimated to account for at least 20% of the variation across individuals. Here we report the results of a genome-wide association study (GWAS) for educational attainment that extends our
Genome-wide association study identifies 74 loci associated with educational attainment
Okbay, Aysu; Beauchamp, Jonathan P.; Fontana, Mark Alan; Lee, James J.; Pers, Tune H.; Rietveld, Cornelius A.; Turley, Patrick; Chen, Guo-Bo; Emilsson, Valur; Meddens, S. Fleur W.; Oskarsson, Sven; Pickrell, Joseph K.; Thom, Kevin; Timshel, Pascal; de Vlaming, Ronald; Abdellaoui, Abdel; Ahluwalia, Tarunveer S.; Bacelis, Jonas; Baumbach, Clemens; Bjornsdottir, Gyda; Brandsma, Johannes H.; Concas, Maria Pina; Derringer, Jaime; Furlotte, Nicholas A.; Galesloot, Tessel E.; Girotto, Giorgia; Gupta, Richa; Hall, Leanne M.; Harris, Sarah E.; Hofer, Edith; Horikoshi, Momoko; Huffman, Jennifer E.; Kaasik, Kadri; Kalafati, Ioanna P.; Karlsson, Robert; Kong, Augustine; Lahti, Jari; van der Lee, Sven J.; de Leeuw, Christiaan; Lind, Penelope A.; Lindgren, Karl-Oskar; Liu, Tian; van der Most, Peter J.; Verweij, Niek; Alizadeh, Behrooz Z.; Vonk, Judith M.; Bultmann, Ute; Franke, Lude; van der Harst, Pim; Penninx, Brenda W. J. H.
2016-01-01
Educational attainment is strongly influenced by social and other environmental factors, but genetic factors are estimated to account for at least 20% of the variation across individuals(1). Here we report the results of a genome-wide association study (GWAS) for educational attainment that extends
Directory of Open Access Journals (Sweden)
Alberto Cargnelutti Filho
2008-12-01
Full Text Available A partir dos dados referentes à temperatura máxima média decendial (Tx e à temperatura média decendial (Tm do ar de 41 municípios do Estado do Rio Grande do Sul, de 1945 a 1974, este trabalho teve como objetivo verificar se a Tx e a Tm podem ser estimadas em função da altitude, latitude e longitude. Para cada um dos 36 decêndios do ano, realizou-se análise de correlação e estimaram-se os parâmetros do modelo das equações de regressão linear múltipla, considerando Tx e Tm como variável dependente e altitude, latitude e longitude como variáveis independentes. Na validação dos modelos de estimativa da Tx e Tm, usou-se o coeficiente de correlação linear de Pearson, entre a Tx e a Tm estimada e a Tx e a Tm observada em dez municípios do Estado, com dados da série de observações meteorológicas de 1975 a 2004. A temperatura máxima média decendial e a temperatura média decendial podem ser estimadas por meio da altitude, latitude e longitude, em qualquer local e decêndio, no Estado do Rio Grande do Sul.The objective of this research was to estimate ten-day maximum (Tx and mean (Tm air temperature using altitude and the geographic coordinates latitude and longitude for the Rio Grande do Sul State, Brazil. Normal ten-day maximum and mean air temperature of 41 counties in the State of Rio Grande do Sul, from 1945 to 1974 were used. Correlation analysis and parameters estimate of multiple linear regression equations were performed using Tx and Tm as dependent variable and altitude, latitude and longitude as independent variables, for the 36 ten-day periods of the year. Pearson's linear correlation coefficient between estimated and observed Tx and Tm, calculated for tem counties using data of were used as independent data sets. The ten-day maximum and mean air temperature may be estimated from the altitude and the geographic coordinates latitude and longitude in the State of Rio Grande do Sul.
Energy Technology Data Exchange (ETDEWEB)
Anon.
2003-09-01
As meant by its name, the RATAC (Regulator with Automatic Temperature and Altitude Compensation) is a brand new system of regulation which automatically counterbalances variations of temperature and altitude having an effect, in some cases, on the gas metering exactitude. Allowing to display real consumption, the RATAC brings more transparency for the marketer and the consumer. Aimed at being used with tanks and piped networks, mainly propane ones, the RATAC was designed by Primagaz and D.B. Consultants, with an active participation of Comap at the levels of validation and industrial development. Comap displayed the RATAC on its booth at the Geneva exhibition, last June, as G. Bruneval (Primagaz) and Daniel Bouvier (D.B. Consultants) made a presentation of the system at the conference. Some extracts of this paper are published below. (O.M.)
Approximate maximum parsimony and ancestral maximum likelihood.
Alon, Noga; Chor, Benny; Pardi, Fabio; Rapoport, Anat
2010-01-01
We explore the maximum parsimony (MP) and ancestral maximum likelihood (AML) criteria in phylogenetic tree reconstruction. Both problems are NP-hard, so we seek approximate solutions. We formulate the two problems as Steiner tree problems under appropriate distances. The gist of our approach is the succinct characterization of Steiner trees for a small number of leaves for the two distances. This enables the use of known Steiner tree approximation algorithms. The approach leads to a 16/9 approximation ratio for AML and asymptotically to a 1.55 approximation ratio for MP.
Threshold altitude for bubble decay and stabilization in rat adipose tissue at hypobaric exposures
DEFF Research Database (Denmark)
Randsoe, Thomas; Larsen, Ole Hyldegaard
2013-01-01
Bubble formation during altitude exposures, causing altitude decompression sickness (aDCS), has been referred to in theoretical models as venous gas embolisms (VGE). This has also been demonstrated by intravascular gas formation. Previous reports indicate that the formation of VGE and aDCS incide...
Bor-Kucukatay, Melek; Colak, Ridvan; Erken, Gülten; Kilic-Toprak, Emine; Kucukatay, Vural
2014-01-01
Altitude training is frequently used by athletes to improve sea-level performance. However, the objective benefits of altitude training are controversial. This study aimed to investigate the possible alterations in hemorheological parameters in response to altitude training. Sprague Dawley rats, were divided into 6 groups: live low-train low (LLTL), live high-train high (LHTH), live high-train low (LHTL) and their controls live high and low (LHALC), live high (LHC), live low (LLC). LHC and LHTH groups were exposed to hypoxia (15% O2, altitudes of 3000 m), 4 weeks. LHALC and LHTL were exposed to 12 hours hypoxia/normoxia per day, 4 weeks. Hypoxia was maintained by a hypoxic tent. The training protocol corresponded to 60-70% of maximal exercise capacity. Rats of training groups ran on treadmill for 20-30 min/day, 4 days/week, 4 weeks. Erythrocyte deformability of LHC group was increased compared to LHALC and LLC. Deformability of LHTH group was higher than LHALC and LLTL groups. No statistically significant alteration in erythrocyte aggregation parameters was observed. There were no significant relationships between RBC deformability and exercise performance. The results of this study show that, living (LHC) and training at altitude (LHTH) seems more advantageous in hemorheological point of view.
Mitaroff, A; Cern, M Silari
2002-01-01
A reference facility for the calibration and intercomparison of active and passive detectors in broad neutron fields has been available at CERN since 1992. A positively charged hadron beam (a mixture of protons and pions) with momentum of 120 GeV/c hits a copper target, 50 cm thick and 7 cm in diameter. The secondary particles produced in the interaction traverse a shield, at 90 degrees with respect to the direction of the incoming beam. made of either 80 to 160 cm of concrete or 40 cm of iron. Behind the iron shield, the resulting neutron spectrum has a maximum at about 1 MeV, with an additional high-energy component. Behind the 80 cm concrete shield, the neutron spectrum has a second pronounced maximum at about 70 MeV and resembles the high-energy component of the radiation field created by cosmic rays at commercial flight altitudes. This paper describes the facility, reports on the latest neutron spectral measurements, gives an overview of the most important experiments performed by the various collaborating institutions over recent years and briefly addresses the possible application of the facility to measurements related to the space programme.
Thoracic skeletal morphology and high-altitude hypoxia in Andean prehistory.
Weinstein, Karen J
2007-09-01
Living humans from the highland Andes exhibit antero-posteriorly and medio-laterally enlarged chests in response to high-altitude hypoxia. This study hypothesizes that morphological responses to high-altitude hypoxia should also be evident in pre-Contact Andean groups. Thoracic skeletal morphology in four groups of human skeletons (N = 347) are compared: two groups from coastal regions (Ancón, Peru, n = 79 and Arica, Chile, n = 123) and two groups from high altitudes (San Pedro de Atacama, Chile, n = 102 and Machu Picchu and Cuzco, Peru, n = 43). Osteometric variables that represent proportions of chest width and depth include sternal and clavicular lengths and breadths and rib length, curvature, and area. Each variable was measured relative to body size, transformed into logarithmic indices, and compared across sex-specific groups using ANOVA and Tukey multiple comparison tests. Atacama highlanders have the largest sternal and clavicular proportions and ribs with the greatest area and least amount of curvature, features that suggest an antero-posteriorly deep and mediolaterally wide thoracic skeleton. Ancón lowlanders exhibit proportions indicating narrower and shallower chests. Machu Picchu and Cuzco males cluster with the other highland group in rib curvature and area at the superior levels of the thorax, whereas chest proportions in Machu Picchu and Cuzco females resemble those of lowlanders. The variation in Machu Picchu and Cuzco males and females is interpreted as the result of population migrations. The presence of morphological traits indicative of enlarged chests in some highland individuals suggests that high-altitude hypoxia was an environmental stressor shaping the biology of highland Andean groups during the pre-Contact period. (c) 2007 Wiley-Liss, Inc.
Environmental Monitoring, Water Quality - Lakes Assessments - Attaining
NSGIC Education | GIS Inventory — This layer shows only attaining lakes of the Integrated List. The Lakes Integrated List represents lake assessments in an integrated format for the Clean Water Act...
Dynamics modeling and control of a transport aircraft for ultra-low altitude airdrop
Directory of Open Access Journals (Sweden)
Liu Ri
2015-04-01
Full Text Available The nonlinear aircraft model with heavy cargo moving inside is derived by using the separation body method, which can describe the influence of the moving cargo on the aircraft attitude and altitude accurately. Furthermore, the nonlinear system is decoupled and linearized through the input–output feedback linearization method. On this basis, an iterative quasi-sliding mode (SM flight controller for speed and pitch angle control is proposed. At the first-level SM, a global dynamic switching function is introduced thus eliminating the reaching phase of the sliding motion. At the second-level SM, a nonlinear function with the property of “smaller errors correspond to bigger gains and bigger errors correspond to saturated gains” is designed to form an integral sliding manifold, and the overcompensation of the integral term to big errors is weakened. Lyapunov-based analysis shows that the controller with strong robustness can reject both constant and time-varying model uncertainties. The performance of the proposed control strategy is verified in a maximum load airdrop mission.
Directory of Open Access Journals (Sweden)
J. P. Burrows
2012-09-01
Full Text Available Measurements of the OH Meinel emissions in the terrestrial nightglow are one of the standard ground-based techniques to retrieve upper mesospheric temperatures. It is often assumed that the emission peak altitudes are not strongly dependent on the vibrational level, although this assumption is not based on convincing experimental evidence. In this study we use Envisat/SCIAMACHY (Scanning Imaging Absorption spectroMeter for Atmospheric CHartographY observations in the near-IR spectral range to retrieve vertical volume emission rate profiles of the OH(3-1, OH(6-2 and OH(8-3 Meinel bands in order to investigate whether systematic differences in emission peak altitudes can be observed between the different OH Meinel bands. The results indicate that the emission peak altitudes are different for the different vibrational levels, with bands originating from higher vibrational levels having higher emission peak altitudes. It is shown that this finding is consistent with the majority of the previously published results. The SCIAMACHY observations yield differences in emission peak altitudes of up to about 4 km between the OH(3-1 and the OH(8-3 band. The observations are complemented by model simulations of the fractional population of the different vibrational levels and of the vibrational level dependence of the emission peak altitude. The model simulations reproduce the observed vibrational level dependence of the emission peak altitude well – both qualitatively and quantitatively – if quenching by atomic oxygen as well as multi-quantum collisional relaxation by O2 is considered. If a linear relationship between emission peak altitude and vibrational level is assumed, then a peak altitude difference of roughly 0.5 km per vibrational level is inferred from both the SCIAMACHY observations and the model simulations.
Altitude Compensating Nozzle Transonic Performance Flight Demonstration, Phase I
National Aeronautics and Space Administration — Altitude compensating nozzles continue to be of interest for use on future launch vehicle boosters and upper stages because of their higher mission average Isp and...
Directory of Open Access Journals (Sweden)
Praveetha Patalay
Full Text Available Evidence for the longitudinal associations between internalising symptom development and academic attainment is sparse and results from existing studies are largely inconclusive. The approaches that have been used in existing studies examining this relationship have in common the limitation of grouping together all individuals in the sample which makes the assumption that the relationship between time, symptoms and attainment across all individuals is the same. The current study aimed to use heterogeneous trajectories of symptom development to examine the longitudinal associations between internalising symptom development and change in academic attainment over a three years period in early adolescence, a key period for internalising symptom development. Internalising symptoms were assessed for 3 consecutive years in a cohort from age 11-14 years (n = 2647, mean age at T1 = 11.7 years. National standardised test scores prior to the first wave and subsequent to the last wave were used as measures of academic attainment. Heterogeneous symptom development trajectories were identified using latent class growth analysis and socio-demographic correlates, such as gender, SES and ethnicity, of the different trajectory groupings were investigated. Derived trajectory groupings were examined as predictors of subsequent academic attainment, controlling for prior attainment. Results demonstrate that symptom trajectories differentially predicted change in academic attainment with increasing trajectories associated with significantly worse academic outcomes when compared to pupils with low levels of symptoms in all waves. Hence, a trajectory based approach provides a more nuanced breakdown of complexities in symptom development and their differential relationships with academic outcomes and in doing so helps clarify the longitudinal relationship between these two key domains of functioning in early adolescence.
Factors associated with lipid goal attainment among acute coronary syndrome patients
Directory of Open Access Journals (Sweden)
Mohd-Zulkefli SZ
2016-08-01
Full Text Available Siti-Zainora Mohd-Zulkefli, Marhanis-Salihah Omar, Adyani Md-Redzuan Faculty of Pharmacy, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia Background: The incidence of acute coronary syndrome (ACS, one of the most common cardiovascular diseases, is high. Lipid goal attainment is one of the important factors to reduce the risk of recurrent heart attack. Identification of factors influencing lipid goal attainment such as age, female, race, underlying comorbidities, intensity of lipid-lowering therapy, patients’ knowledge, and patients’ belief about medicine would be beneficial in achieving the lipid goal. This study is aimed to determine lipid profile attainment and prescribing pattern of lipid-lowering therapy as well as to identify factors influencing lipid profile attainment among ACS patients.Patients and methods: This researcher-assisted cross-sectional survey was carried out at a cardiology clinic in a tertiary hospital from March to May 2015.Results: A total of 101 ACS patients were involved in this study. The mean values for low-density lipoprotein cholesterol (LDL-C and high-density lipoprotein cholesterol levels were 2.75 (0.82 mmol/L and 1.14 (0.27 mmol/L, respectively, while the median value for triglyceride level was 2.75 (0.82 mmol/L. Only 15.8% of our participants achieved the targeted LDL-C. Simvastatin 20 mg was the most common regimen prescribed. Predictors for better LDL-C attainment were younger age (β=-0.228; P=0.032 and higher knowledge score (β=-0.255; P=0.049, while predictors for high-density lipoprotein cholesterol attainment were male (β=0.268; P=0.006, smoking (β=-0.192; P=0.045, and higher knowledge score (β=-0.195; P=0.039. Smoking (β=-0.361; P<0.0001 was the only predictor for higher triglyceride level.Conclusion: Younger age, female, lower knowledge score, and smoking status are good predictors for lipid attainment among ACS patients. Keywords: influence, disease, drug use, patient
14 CFR 91.119 - Minimum safe altitudes: General.
2010-01-01
... than 500 feet to any person, vessel, vehicle, or structure. (d) Helicopters. Helicopters may be... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Minimum safe altitudes: General. 91.119 Section 91.119 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION...
Regional Disparities in Education Attainment Level in the European Union: A Spatial Approach
Directory of Open Access Journals (Sweden)
Chocholatá Michaela
2017-10-01
Full Text Available This article deals with the analysis of education attainment level across the 252 NUTS 2 regions of the European Union (EU with consideration of the spatial aspect. Since the individual EU regions cannot be seen as isolated, the main aim of this article is to assess the impact of location on the education attainment level (percentage of population aged 25–64 with at least upper secondary education during the period 2007–2015, as well as to investigate the impact of regional growth 2014/2007 on the education attainment level in 2015. The spatial analysis proved the existence of positive spatial autocorrelation and persistence of disparities in education attainment level across EU regions during the analysed period. The results of econometric analysis confirmed the expected positive impact of economic growth on education attainment level as well as the necessity to incorporate the spatial dimension into the model.
The Effects of a 10-day Altitude Training Camp at 1828 Meters on Varsity Cross-Country Runners.
Diebel, Sebastian R; Newhouse, Ian; Thompson, David S; Johnson, Vineet B K
2017-01-01
Altitude training has been shown to alter blood lactate (BL) levels due to alterations resulting from acclimatization. This study aims to estimate the impact of altitude training on BL changes immediately following an incremental treadmill test and during recovery before and after 10-day altitude training at approximately 1828 meters. Eight varsity cross-country runners performed an incremental treadmill test (ITT), pre and post-altitude training. Resting and post-warm-up BL values were recorded. During ITT, heart rate (HR), oxygen saturation (SpO2), and time to exhaustion were monitored. BL was also measured post-ITT at 0, 2, 4, 6, and 8 minutes. The average of all BL values was higher following altitude intervention (8.8 ± 4.6 mmol/L) compared to pre-intervention (7.4 ± 3.3 mmol/L). These differences were statistically significant ( t (6) = -2.40, p = .026). BL immediately (0 minutes) after the ITT was higher following the altitude intervention (13.6 ± 3.6 mmol/L) compared to pre-intervention (9.7 ± 3.8 mmol/L) and was statistically significant ( t (7) = -3.30, p = .006). Average HR during the ITT was lower following the altitude intervention (176.9 ± 11.1 bpm) compared to pre (187 ± 9.5 bpm), these differences were statistically significant ( t (28)= 18.07, p= altitude intervention at 1828 meters may benefit varsity cross-country runners. The higher post-exercise BL may be attributed to more anaerobic contributions. Lower HR may suggest a larger stroke volume and/or more efficient O2 carrying capacity.
Educational attainment and obesity: a systematic review.
Cohen, A K; Rai, M; Rehkopf, D H; Abrams, B
2013-12-01
Although previous systematic reviews considered the relationship between socioeconomic status and obesity, almost 200 peer-reviewed articles have been published since the last review on that topic, and this paper focuses specifically on education, which has different implications. The authors systematically review the peer-reviewed literature from around the world considering the association between educational attainment and obesity. Databases from public health and medicine, education, psychology, economics, and other social sciences were searched, and articles published in English, French, Portuguese and Spanish were included. This paper includes 289 articles that report on 410 populations in 91 countries. The relationship between educational attainment and obesity was modified by both gender and the country's economic development level: an inverse association was more common in studies of higher-income countries and a positive association was more common in lower-income countries, with stronger social patterning among women. Relatively few studies reported on lower-income countries, controlled for a comprehensive set of potential confounding variables and/or attempted to assess causality through the use of quasi-experimental designs. Future research should address these gaps to understand if the relationship between educational attainment and obesity may be causal, thus supporting education policy as a tool for obesity prevention. © 2013 The Authors. obesity reviews © 2013 International Association for the Study of Obesity.
DNA methylation signatures of educational attainment
van Dongen, Jenny; Bonder, Marc Jan; Dekkers, Koen F.; Nivard, Michel G.; van Iterson, Maarten; Willemsen, Gonneke; Beekman, Marian; van der Spek, Ashley; van Meurs, Joyce B. J.; Franke, Lude; Heijmans, Bastiaan T.; van Duijn, Cornelia M.; Slagboom, P. Eline; Boomsma, Dorret I.; BIOS consortium
2018-03-01
Educational attainment is a key behavioural measure in studies of cognitive and physical health, and socioeconomic status. We measured DNA methylation at 410,746 CpGs (N = 4152) and identified 58 CpGs associated with educational attainment at loci characterized by pleiotropic functions shared with neuronal, immune and developmental processes. Associations overlapped with those for smoking behaviour, but remained after accounting for smoking at many CpGs: Effect sizes were on average 28% smaller and genome-wide significant at 11 CpGs after adjusting for smoking and were 62% smaller in never smokers. We examined sources and biological implications of education-related methylation differences, demonstrating correlations with maternal prenatal folate, smoking and air pollution signatures, and associations with gene expression in cis, dynamic methylation in foetal brain, and correlations between blood and brain. Our findings show that the methylome of lower-educated people resembles that of smokers beyond effects of their own smoking behaviour and shows traces of various other exposures.
Alsing, Justin; Silva, Hector O.; Berti, Emanuele
2018-04-01
We infer the mass distribution of neutron stars in binary systems using a flexible Gaussian mixture model and use Bayesian model selection to explore evidence for multi-modality and a sharp cut-off in the mass distribution. We find overwhelming evidence for a bimodal distribution, in agreement with previous literature, and report for the first time positive evidence for a sharp cut-off at a maximum neutron star mass. We measure the maximum mass to be 2.0M⊙ sharp cut-off is interpreted as the maximum stable neutron star mass allowed by the equation of state of dense matter, our measurement puts constraints on the equation of state. For a set of realistic equations of state that support >2M⊙ neutron stars, our inference of mmax is able to distinguish between models at odds ratios of up to 12: 1, whilst under a flexible piecewise polytropic equation of state model our maximum mass measurement improves constraints on the pressure at 3 - 7 × the nuclear saturation density by ˜30 - 50% compared to simply requiring mmax > 2M⊙. We obtain a lower bound on the maximum sound speed attained inside the neutron star of c_s^max > 0.63c (99.8%), ruling out c_s^max c/√{3} at high significance. Our constraints on the maximum neutron star mass strengthen the case for neutron star-neutron star mergers as the primary source of short gamma-ray bursts.
Estimation of 557.7 nm Emission Altitude using Co-located Lidars and Photometers over Arecibo
Franco, E.; Raizada, S.; Lautenbach, J.; Brum, C. G. M.
2017-12-01
Airglow at 557.7 nm (green line emission) is generated through the Barth mechanism in the E-region altitude and is sometimes associated with red line (630.0 nm) originating at F-region altitudes. Photons at 557.7 nm are produced through the quenching of excited atomic oxygen atoms, O(1S), while 630.0 nm results through the de-excitation of O(1D) atoms. Even though, the contribution of the green line from F-region is negligible and the significant component comes from the mesosphere, this uncertainty gives rise to a question related to its precise altitude. Previous studies have shown that perturbations generated by atmospheric gravity Waves (GWs) alter the airglow intensity and can be used for studying dynamics of the region where it originates. The uncertainty in the emission altitude of green line can be resolved by using co-located lidars, which provide altitude resolved metal densities. At Arecibo, the resonance lidars tuned to Na and K resonance wavelengths at 589 nm and 770 nm can be used in conjunction with simultaneous measurements from green line photometer to resolve this issue. Both photometer and lidars have narrow field of view as compared to airglow imagers, and hence provide an added advantage that these instruments sample same GW spectrum. Hence, correlation between density perturbations inferred from lidars and airglow intensity perturbations can shed light on the exact altitude of green line emission.
Systems Design and Experimental Evaluation of a High-Altitude Relight Test Facility
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
Outdoor altitude stabilization of QuadRotor based on type-2 fuzzy and fuzzy PID
Wicaksono, H.; Yusuf, Y. G.; Kristanto, C.; Haryanto, L.
2017-11-01
This paper presents a design of altitude stabilization of QuadRotor based on type-2 fuzzy and fuzzy PID. This practical design is implemented outdoor. Barometric and sonar sensor were used in this experiment as an input for the controller YoHe. The throttle signal as a control input was provided by the controller to leveling QuadRotor in particular altitude and known well as altitude stabilization. The parameter of type-2 fuzzy and fuzzy PID was tuned in several heights to get the best control parameter for any height. Type-2 fuzzy produced better result than fuzzy PID but had a slow response in the beginning.
Directory of Open Access Journals (Sweden)
Juan F. Pérez-Bayer
2013-09-01
Full Text Available Cerca de 2500 millones de personas dependen de la leña como su principal combustible para calefacción y cocción.En este trabajo se estudia el efecto de la altitud (678 y 1976 metros sobre el nivel del mar, msnm en el desempeño energético y las emisiones de una estufa de cocción eco-eficiente con biomasa.Los experimentos se llevaron a cabo bajo las pruebas de ebullición de agua y cocción controlada. El rendimiento disminuyó 24% al aumentar la altitud en la prueba de ebullición, y el consumo específico de combustible aumentó 27,3% debido a los cambios en la densidad del aire. En la prueba de cocción controlada, el consumo específico de combustible y las emisiones específicas aumentaron 15,3% y 16%, respectivamente. La altitud afectó significativamente el desempeño de la estufa tipo "Plancha", por lo que es necesario el rediseño de las estufas de acuerdo a su ubicación geográfica con el fin de optimizar el proceso de cocción.Palabras claves: estufa de cocción eco-eficiente, biomasa, combustión, altitud, energía y emisiones, pruebas de desempeño WBT–CCT.______________________________________________________________________________AbstractAround 2.5 billion people depend on wood as their main fuel for heating and cooking.In this work is studied the effect of altitude (678 and 1976 meters above sea level on energy performance and emissions of an improved wood stove under standardized cooking tests. The experiments were carried out under the Water Boiling (WBTand Controlled Cooking (CCT Tests. The efficiency decreased about 24% with increasing altitude in WBT, and specific fuel consumption increased 27.3% due to the air density changes. Regarding the controlled cooking test, the specific fuel consumption and specific emissions increased by 15.3% and 16 %, respectively. It is highlighted that altitude significantly affects the “Plancha” wood stove behavior. Specific emissions increased at higher altitudes, so it is
Asthma in Patients Climbing to High and Extreme Altitudes in the Tibetan Everest Region
Huismans, Henrike K.; Douma, W. Rob; Kerstjens, Huib A. M.; Renkema, Tineke E. J.
Objectives: The aim of this study was to investigate the behavior of asthma in patients traveling to high and extreme altitudes. Methods: Twenty-four Dutch patients with mild asthma did a trekking at high and extreme altitudes (up to 6410 m = 21030 ft) in the Tibetan Everest region. Asthma symptoms,
Personality and the Intergenerational Transmission of Educational Attainment: Evidence from Germany
Ryberg, Renee; Bauldry, Shawn; Schultz, Michael A.; Steinhoff, Annekatrin; Shanahan, Michael
2018-01-01
Research based in the United States, with its relatively open educational system, has found that personality mediates the relationship between parents’ and child’s educational attainment and this meditational pattern is especially beneficial to students from less-educated households. Yet in highly structured, competitive educational systems, personal characteristics may not predict attainment or may be more or less consequential at different points in the educational career. We examine the salience of personality in the educational attainment process in the German educational system. Data come from a longitudinal sample of 682 seventeen to twenty-five year-olds (54% female) from the 2005 and 2015 German Socio-Economic Panel (SOEP). Results show that adolescent personality traits — openness, neuroticism, and conscientiousness — are associated with educational attainment, but personality plays a negligible role in the intergenerational transmission of education. Personality is influential before the decision about the type of secondary degree that a student will pursue (during adolescence). After that turning point, when students have entered different pathways through the system, personality is less salient. Cross-national comparisons in a life course framework broaden the scope of current research on non-cognitive skills and processes of socioeconomic attainment, alerting the analyst to the importance of both institutional structures and the changing importance of these skills at different points in the life course. PMID:28707154
Personality and the Intergenerational Transmission of Educational Attainment: Evidence from Germany.
Ryberg, Renee; Bauldry, Shawn; Schultz, Michael A; Steinhoff, Annekatrin; Shanahan, Michael
2017-10-01
Research based in the United States, with its relatively open educational system, has found that personality mediates the relationship between parents' and child's educational attainment and this mediational pattern is especially beneficial to students from less-educated households. Yet in highly structured, competitive educational systems, personality characteristics may not predict attainment or may be more or less consequential at different points in the educational career. We examine the salience of personality in the educational attainment process in the German educational system. Data come from a longitudinal sample of 682 17 to 25 year-olds (54% female) from the 2005 and 2015 German Socio-Economic Panel (SOEP). Results show that adolescent personality traits-openness, neuroticism, and conscientiousness-are associated with educational attainment, but personality plays a negligible role in the intergenerational transmission of education. Personality is influential before the decision about the type of secondary degree that a student will pursue (during adolescence). After that turning point, when students have entered different pathways through the system, personality is less salient. Cross-national comparisons in a life course framework broaden the scope of current research on non-cognitive skills and processes of socioeconomic attainment, alerting the analyst to the importance of both institutional structures and the changing importance of these skills at different points in the life course.
ACUTE PHASE PROTEIN INCREASE IN HIGH ALTITUDE MOUNTAINEERS
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Tolga Saka
Full Text Available ABSTRACT Introduction: Many middle-aged Turks go hiking in mountains to breathe some fresh air or to maintain fitness. Objective: This study investigated the effects of regular high altitude mountain climbing on the metabolic and hematological responses of mountaineers. Methods: Hematological and biochemical parameters were studied, as well as some hormonal values of 21 mountaineers and 16 healthy age-matched sedentary volunteers. Results: The neutrophil to lymphocyte ratio (NLR was significantly lower (p<0.04 in mountaineers compared with the sedentary group. Total protein (p<0.001 and albumin (p<0.001 were lower, while the levels of ferritin (p<0.04, creatine (p<0.03 and creatine phosphokinase (p<0.01 were higher in mountaineers. Other hematological and biochemical parameters, i.e., erythrocytes, leukocytes, hemoglobin and hematocrit, did not change significantly. Conclusion: Our results show that regular exposure to high altitude increased the serum levels of some acute phase proteins with anti-inflammatory properties.
Ascent to moderate altitude impairs overnight memory improvements.
Tesler, Noemi; Latshang, Tsogyal D; Lo Cascio, Christian M; Stadelmann, Katrin; Stoewhas, Anne-Christin; Kohler, Malcolm; Bloch, Konrad E; Achermann, Peter; Huber, Reto
2015-02-01
Several studies showed beneficial effects of sleep on memory performance. Slow waves, the electroencephalographic characteristic of deep sleep, reflected on the neuronal level by synchronous slow oscillations, seem crucial for these benefits. Traveling to moderate altitudes decreases deep sleep. In a randomized cross-over design healthy male subjects performed a visuo-motor learning task in Zurich (490 m) and at Davos Jakobshorn (2590 m) in random order. Memory performance was assessed immediately after learning, before sleep, and in the morning after a night of sleep. Sleep EEG recordings were performed during the nights. Our findings show an altitude induced reduction of sleep dependent memory performance. Moreover, this impaired sleep dependent memory performance was associated with reduced slow wave derived measures of neuronal synchronization. Our results are consistent with a critical role of slow waves for the beneficial effects of sleep on memory that is susceptible to natural environmental influences. Copyright © 2014 Elsevier Inc. All rights reserved.
Cosmic microwave background science at commercial airline altitudes
Feeney, Stephen M.; Gudmundsson, Jon E.; Peiris, Hiranya V.; Verde, Licia; Errard, Josquin
2017-07-01
Obtaining high-sensitivity measurements of degree-scale cosmic microwave background (CMB) polarization is the most direct path to detecting primordial gravitational waves. Robustly recovering any primordial signal from the dominant foreground emission will require high-fidelity observations at multiple frequencies, with excellent control of systematics. We explore the potential for a new platform for CMB observations, the Airlander 10 hybrid air vehicle, to perform this task. We show that the Airlander 10 platform, operating at commercial airline altitudes, is well suited to mapping frequencies above 220 GHz, which are critical for cleaning CMB maps of dust emission. Optimizing the distribution of detectors across frequencies, we forecast the ability of Airlander 10 to clean foregrounds of varying complexity as a function of altitude, demonstrating its complementarity with both existing (Planck) and ongoing (C-BASS) foreground observations. This novel platform could play a key role in defining our ultimate view of the polarized microwave sky.
Energy Technology Data Exchange (ETDEWEB)
Pérez-Bayer, Juan F.; Graciano-Bustamante, Diana S.; Gómez-Betancur, José A. [Universidad de Antioquia. Grupo de manejo eficiente de la energía. Medellín (Colombia)
2013-07-01
Around 2.5 billion people depend on wood as their main fuel for heating and cooking.In this work is studied the effect of altitude (678 and 1976 meters above sea level) on energy performance and emissions of an improved wood stove under standardized cooking tests. The experiments were carried out under the Water Boiling (WBT) and Controlled Cooking (CCT) Tests. The efficiency decreased about 24 % with increasing altitude in WBT, and specific fuel consumption increased 27.3 % due to the air density changes. Regarding the controlled cooking test, the specific fuel consumption and specific emissions increased by 15.3 % and 16 %, respectively. It is highlighted that altitude significantly affects the 'Plancha' wood stove behavior. Specific emissions increased at higher altitudes, so it is necessary to redesign wood stoves according to their geographical location in order to optimize the cooking process. (author)
Numerical research on the thermal performance of high altitude scientific balloons
International Nuclear Information System (INIS)
Dai, Qiumin; Xing, Daoming; Fang, Xiande; Zhao, Yingjie
2017-01-01
Highlights: • A model is presented to evaluate the IR radiation between translucent surfaces. • Comprehensive ascent and thermal models of balloons are established. • The effect of IR transmissivity on film temperature distribution is unneglectable. • Atmospheric IR radiation is the primary thermal factor of balloons at night. • Solar radiation is the primary thermal factor of balloons during the day. - Abstract: Internal infrared (IR) radiation is an important factor that affects the thermal performance of high altitude balloons. The internal IR radiation is commonly neglected or treated as the IR radiation between opaque gray bodies. In this paper, a mathematical model which considers the IR transmissivity of the film is proposed to estimate the internal IR radiation. Comprehensive ascent and thermal models for high altitude scientific balloons are established. Based on the models, thermal characteristics of a NASA super pressure balloon are simulated. The effects of film IR property on the thermal behaviors of the balloon are discussed in detail. The results are helpful for the design and operation of high altitude scientific balloons.
Reginatto, M; Neumann, S
2002-01-01
MAXED was developed to apply the maximum entropy principle to the unfolding of neutron spectrometric measurements. The approach followed in MAXED has several features that make it attractive: it permits inclusion of a priori information in a well-defined and mathematically consistent way, the algorithm used to derive the solution spectrum is not ad hoc (it can be justified on the basis of arguments that originate in information theory), and the solution spectrum is a non-negative function that can be written in closed form. This last feature permits the use of standard methods for the sensitivity analysis and propagation of uncertainties of MAXED solution spectra. We illustrate its use with unfoldings of NE 213 scintillation detector measurements of photon calibration spectra, and of multisphere neutron spectrometer measurements of cosmic-ray induced neutrons at high altitude (approx 20 km) in the atmosphere.
Diebel, Sebastian R; Newhouse, Ian; Thompson, David S; Johnson, Vineet B K
2017-01-01
Running economy (RE) and VO 2 max are important predictors of endurance performance for elite and semi-elite endurance athletes, with RE being an appropriate predictor in a homogenous running population. Altitude training has been observed to change RE (mL.kg -1 .min -1 ), and VO 2 max due to alterations resulting from acclimatization. This study tracked changes in RE and VO 2 max before and after a 10-day altitude training camp at 1828 meters. VO 2 max, RE expressed calorically, and respiratory exchange ratio (RER), were measured below anaerobic threshold (AT) to observe differences between pre-and post-altitude training. Eight varsity cross-country runners between the ages of 18 and 22 years performed an incremental treadmill test, pre- and post-10-day altitude training. Paired samples t-tests were used to statistically analyze the data. Average RE (VO 2 mL.kg -1 .min -1 ) improved following altitude intervention ( M = 56.44 ± 4.28) compared to pre-altitude training (61.30 ± 7.56). These differences were statistically significant t ( 7 )= 2.71, p =.014. RE expressed as kcals.kg -1 .km -1 improved following altitude training (16.73 ± 2.96) compared to (18.44 ± 4.04) pre-altitude training and was statistically significant t( 7 ) =3.08, p = .008. RER taken during the last minute of steady-state was higher (0.97, ± .019) post-altitude training, compared to (0.90 ± .043) pre-altitude. These differences were statistically significant t ( 7 ) -3.62, p =.008. VO 2 max (mL.kg -1 .min -1 ) was lower in 6 out of 8 participants (63.91, ± 8.65) post-altitude compared to (69.90, ± 10.80) pre-altitude and was statistically significant t( 7 ) = 2.33, p =.026. The observed improvements in RE may be beneficial for endurance athletes competing and/or training at moderate altitudes near 1828 meters.
Tests of the Daimler D-IVa Engine at a High Altitude Test Bench
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.
Panataria, Lince R.; Lubis, Ramli
2018-03-01
This study is aimed at finding out vegetative growth of some varieties of sugarcane on different altitudes. The study applied Factorial Randomized Block Design comprising two factors. The first factor was varieties of consisting of three levels: BM 13579, Ps. 92-1, and Ps. 89-1. The second factor was altitudes of the land with three different levels of altitudes: Kebun Saentis (15 MASL), district of Pancurbatu (±300 MASL), and district of Sibolangit (±700 MASL). The study resulted in that variety of sugarcane, altitudes, and the interaction of both variables affected these: the leaf area on observations of 21, 42, 63, and 84 daps, number of tillers, root volume, nutrient uptake on observation 84 daps. The best quality of the sugarcane varieties was variety Ps. 92-1 on altitude 15 MASL (Kebun Saentis), followed by an altitude ±300 MASL (district of Pancurbatu), and then on ±700 MASL (district of Sibolangit); while the worst quality of the variety was variety BM 13579 of altitude 15 MASL (Kebun Saentis).
Chen, Chung-Yu; Hou, Chien-Wen; Bernard, Jeffrey R; Chen, Chiu-Chou; Hung, Ta-Cheng; Cheng, Lu-Ling; Liao, Yi-Hung; Kuo, Chia-Hua
2014-09-01
High altitude training is a widely used strategy for improving aerobic exercise performance. Both Rhodiola crenulata (R) and Cordyceps sinensis (C) supplements have been reported to improve exercise performance. However, it is not clear whether the provision of R and C during high altitude training could further enhance aerobic endurance capacity. In this study, we examined the effect of R and C based supplementation on aerobic exercise capacity following 2-week high altitude training. Alterations to autonomic nervous system activity, circulatory hormonal, and hematological profiles were investigated. Eighteen male subjects were divided into two groups: Placebo (n=9) and R/C supplementation (RC, n=9). Both groups received either RC (R: 1400 mg+C: 600 mg per day) or the placebo during a 2-week training period at an altitude of 2200 m. After 2 weeks of altitude training, compared with Placebo group, the exhaustive run time was markedly longer (Placebo: +2.2% vs. RC: +5.7%; paltitude training (paltitude training provides greater training benefits in improving aerobic performance. This beneficial effect of RC treatment may result from better maintenance of PNS activity and accelerated physiological adaptations during high altitude training.
Genomic analysis of natural selection and phenotypic variation in high-altitude mongolians.
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Jinchuan Xing
Full Text Available Deedu (DU Mongolians, who migrated from the Mongolian steppes to the Qinghai-Tibetan Plateau approximately 500 years ago, are challenged by environmental conditions similar to native Tibetan highlanders. Identification of adaptive genetic factors in this population could provide insight into coordinated physiological responses to this environment. Here we examine genomic and phenotypic variation in this unique population and present the first complete analysis of a Mongolian whole-genome sequence. High-density SNP array data demonstrate that DU Mongolians share genetic ancestry with other Mongolian as well as Tibetan populations, specifically in genomic regions related with adaptation to high altitude. Several selection candidate genes identified in DU Mongolians are shared with other Asian groups (e.g., EDAR, neighboring Tibetan populations (including high-altitude candidates EPAS1, PKLR, and CYP2E1, as well as genes previously hypothesized to be associated with metabolic adaptation (e.g., PPARG. Hemoglobin concentration, a trait associated with high-altitude adaptation in Tibetans, is at an intermediate level in DU Mongolians compared to Tibetans and Han Chinese at comparable altitude. Whole-genome sequence from a DU Mongolian (Tianjiao1 shows that about 2% of the genomic variants, including more than 300 protein-coding changes, are specific to this individual. Our analyses of DU Mongolians and the first Mongolian genome provide valuable insight into genetic adaptation to extreme environments.
The role of oxygen-increased respirator in humans ascending to high altitude
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Shen Guanghao
2012-08-01
Full Text Available Abstract Background Acute mountain sickness (AMS is common for people who live in low altitude areas ascending to the high altitude. Many instruments have been developed to treat mild cases of AMS. However, long-lasting and portable anti-hypoxia equipment for individual is not yet available. Methods Oxygen-increased respirator (OIR has been designed to reduce the risk of acute mountain sickness in acute exposure to low air pressure. It can increase the density of oxygen by increasing total atmospheric pressure in a mask. Male subjects were screened, and eighty-eight were qualified to perform the experiments. The subjects were divided into 5 groups and were involved in some of the tests at 4 different altitudes (Group 1, 2: 3700 m; Group 3,4,5: 4000 m, 4700 m, 5380 m with and without OIR. These tests include heart rate, saturation of peripheral oxygen (SpO2, malondialdehyde (MDA, superoxide dismutase (SOD, blood lactate (BLA and PWC (physical work capacity -170. Results The results showed that higher SpO2, lower heart rate (except during exercise and better recovery of heart rate were observed from all the subjects ’with OIR’ compared with ’without OIR’ (P Conclusions We suggested that OIR may play a useful role in protecting people ascending to high altitude before acclimatization.
Bonne, Thomas Christian; Lundby, Carsten; Lundby, Anne Kristine; Sander, Mikael; Bejder, Jacob; Nordsborg, Nikolai Baastrup
2015-08-01
The impact of altitude training on haematological parameters and the Athlete Biological Passport (ABP) was evaluated in international-level elite athletes. One group of swimmers lived high and trained high (LHTH, n = 10) for three to four weeks at 2130 m or higher whereas a control group (n = 10) completed a three-week training camp at sea-level. Haematological parameters were determined weekly three times before and four times after the training camps. ABP thresholds for haemoglobin concentration ([Hb]), reticulocyte percentage (RET%), OFF score and the abnormal blood profile score (ABPS) were calculated using the Bayesian model. After altitude training, six swimmers exceeded the 99% ABP thresholds: two swimmers exceeded the OFF score thresholds at day +7; one swimmer exceeded the OFF score threshold at day +28; one swimmer exceeded the threshold for RET% at day +14; and one swimmer surpassed the ABPS threshold at day +14. In the control group, no values exceeded the individual ABP reference range. In conclusion, LHTH induces haematological changes in Olympic-level elite athletes which can exceed the individually generated references in the ABP. Training at altitude should be considered a confounding factor for ABP interpretation for up to four weeks after altitude exposure but does not consistently cause abnormal values in the ABP. Copyright © 2014 John Wiley & Sons, Ltd.
DEFF Research Database (Denmark)
Funder, Svend Visby; Hansen, Louise
1996-01-01
there was little change at all. The driving factor during this step was calving caused by rising sea level. This lasted until c. 10 ka, but may have been consumated before the Younger Dryas. The second step began with a glacier-readvance between 10 and 9.5 ka, and after this the fjord glaciers began to retreat....... Maximum Holocene uplift was attained in areas of the 10 ka ice margin, indicating that the uplift is essentially a response to the melting and unloading of ice that began at this time. In suppport of this, recent results in West, North and East Greenland indicate that the...
Test de caminata de 6 minutos en pacientes de rehabilitación cardiaca de altitud moderada
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Nelson F. González
2017-11-01
walk test in cardiac rehabilitation is and effective and safe tool for the evaluation of functional status, as well of the effectiveness of the therapy, the adjustment of training methods, and to establish the morbidity and mortality prognosis. Objective: To investigate the aspects that affect the physiological response in the 6-minute walk test in cardiovascular rehabilitation patients at moderate altitudes (2,550 metres above sea level, and determine the clinical importance. Material and methods: A descriptive study was conducted on 487 six-minute walks by patients with ages between 18 and 80 years, enrolled in cardiac rehabilitation programme and who lived at a moderate altitude. Results: The Colombian cardiovascular patients covered shorter distances than those demonstrated in other populations and other diseases. The heart rate during the test increased by 40 beats per minute and reached 65% of the maximum heart rate, as such that the systolic blood pressure increased by 20 mmHg. The perception of central and peripheral effort also increased up to 4 points on the Borg scale, as well as a mean decrease of 3% in oxygen saturation. Conclusion: The 6-minute test is safe and well-tolerated in cardiovascular patients living at moderate altitudes. Significant changes were seen during the walk as regards chronotropic response, pressure, perception of effort, oxygen saturation levels, which were different from the results found at sea level. This phenomenon provides reference values for tests performed on cardiovascular patients at moderate altitudes, as well as for the clinical approach to the evaluation of the functional capacity, physical independence, falls risk, adjustments to medication, and an integral assessment of comorbidities. Palabras clave: Enfermedad cardiovascular, Rehabilitación, Test, Ejercicio, Hipoxia, Keywords: Cardiovascular disease, Rehabilitation, Test, Exercise, Hypoxia
How to attain expertise in clinical communication?
Wouda, Jan C.; van de Wiel, Harry B. M.
2013-01-01
Several factors complicate the attainment of expertise in clinical communication. Medical curricula and postgraduate training insufficiently provide the required learning conditions of deliberate practice to overcome these obstacles. In this paper we provide recommendations for learning objectives
Havryliuk, Tatiana; Acharya, Bhuwan; Caruso, Emily; Cushing, Tracy
2015-09-01
We surveyed Nepali porters and guides as well as English- and non-English-speaking trekkers on their knowledge of altitude illness and its treatment during trekking expeditions to the Annapurna region of Nepal. From March 15 to April 15, 2014, Nepali porters and visiting trekkers were surveyed regarding their ability to recognize and treat altitude illness in Manang, Nepal (3540 m). Their personal use of medications and home remedies and presence of acute mountain sickness (AMS) symptoms were also assessed. 504 subjects were surveyed, including 108 Nepalis. Overall incidence of AMS symptoms was 16%, 5% among Nepalis, and 21% among trekkers. Subjects recognized that headache (88%) was one of the symptoms of AMS, however many reported not knowing the symptoms of high altitude pulmonary edema (40%) or high altitude cerebral edema (42%). 58% of subjects reported carrying and 16% reported taking acetazolamide, while only 2 (0.4%) respondents took dexamethasone. The majority of subjects reported that they would be able to recognize (67%) and treat (62%) altitude illness. Trekkers reported a higher incidence of AMS symptoms than Nepalis. Although most respondents recognized symptoms of AMS, both Nepalis and trekkers lacked knowledge regarding more serious presentations of altitude illness, thus both groups were overconfident in their ability to recognize and treat altitude illness.
Socioeconomic Attainment of Extremely Low Birth Weight Survivors: The Role of Early Cognition.
Dobson, Kathleen G; Ferro, Mark A; Boyle, Michael H; Schmidt, Louis A; Saigal, Saroj; Van Lieshout, Ryan J
2017-03-01
To determine: (1) if childhood cognitive and academic abilities mediate the association between being born at extremely low birth weight (ELBW) and socioeconomic attainment at age 29 to 36 years; (2) which cognitive abilities (IQ, verbal abilities, fluid intelligence, mathematical abilities, or academic achievement) most strongly mediate this association; and (3) if the mediating role of cognition is different in ELBW survivors with significant neurosensory impairment (NSI). A prospective, longitudinal cohort of 100 Canadian ELBW survivors born between 1977 and 1982 and 89 normal birth weight comparison participants were used to examine the mediating role of childhood cognition by using 5 cognitive mediators assessed at age 8 years (overall IQ, verbal IQ, performance IQ, quantitative ability, and academic achievement) on socioeconomic attainment at adulthood. Socioeconomic attainment was defined as personal annual earnings and full-time employment assessed via self-report at age 29 to 36 years. Mediation models revealed that childhood cognition mediated the association between ELBW status and income attainment, with mathematical abilities and overall IQ each accounting for 26% of the direct effect. Mediated effects were not statistically significant in full-time employment models. For both outcomes, the mediating effect of cognition was stronger for ELBW survivors with NSI. Childhood cognitive abilities partially mediate associations between ELBW status and adult income attainment. Early life cognition is a critical predictor of socioeconomic attainment in ELBW survivors, particularly in those born with NSI. Interventions aimed at enhancing early cognition in ELBW survivors may help optimize their later socioeconomic attainment. Copyright © 2017 by the American Academy of Pediatrics.
Directory of Open Access Journals (Sweden)
Long Chen
2016-01-01
Full Text Available Vegetation plays a very important role of carbon (C sinks in the global C cycle. With its complex terrain and diverse vegetation types, the Lancang River Basin (LRB of southwest China has huge C storage capacity. Therefore, understanding the spatial variations and controlling mechanisms of vegetation C storage is important to understand the regional C cycle. In this study, data from a forest inventory and field plots were used to estimate and map vegetation C storage distribution in the LRB, to qualify the quantitative relationships between vegetation C density and altitude at sublot and township scale, and a linear model or polynomial model was used to identify the relationship between C density and altitude at two spatial scales and two statistical scales. The results showed that a total of 300.32 Tg C was stored in the LRB, an important C sink in China. The majority of C storage was contributed by forests, notably oaks. The vegetation C storage exhibited nonlinear variation with latitudinal gradients. Altitude had tremendous influences on spatial patterns of vegetation C storage of three geomorphological types in the LRB. C storage decreased with increasing altitude at both town and sublot scales in the flat river valley (FRV region and the mid-low mountains gorge (MMG region, and first increased then decreased in the alpine gorge (AG region. This revealed that, in southwest China, altitude changes the latitudinal patterns of vegetation C storage; especially in the AG area, C density in the mid-altitude (3100 m area was higher than that of adjacent areas.
Social Justice and Lower Attainers in a Global Knowledge Economy
Sally Tomlinson
2013-01-01
National governments believe that higher levels of educational attainments and training are necessary for successful competition in knowledge-driven economies and all young people are urged to invest in their own human capital and learn new skills. Moves towards inclusive education have brought into mainstream schools and colleges many who would formerly have been segregated in special schooling or otherwise given minimum education, joining those simply regarded as lower attainers. More resea...
Schooling or Social Origin? The Bias in the Effect of Educational Attainment on Social Orientations
Sieben, I.J.P.; Graaf, P.M. de
2004-01-01
The strong relationship between educational attainment and social attitudes and behaviour is often explained as an effect of schooling. However, educational attainment also reflects social origins. In order to obtain a view of the unbiased effect of educational attainment on social orientations,
Directory of Open Access Journals (Sweden)
Ozan Sever
2017-10-01
Full Text Available In the study, the acute response of the 2000m maximal aerobic test on the biathletes living at different altitudes was analyzed. A total of 67 athletes (Mean age = 14,69 ± 1,22, Mean BMI = 19.60 ± 2.29 consisting of boys and girls represent the sample of the study who were tested during the qualification process of Turkey national team. The athletes divided into two groups. Thirty-two of the athletes living above the altitude of 1500m (considered as the altitude where physiological adaptation occurs coded as the high-altitude group, and thirty-five living below 1500m coded as the low altitude group. A shuttle-run test was applied to measure the aerobic power of the athletes. During the test, the heart rates were monitored continuously. The athletes living above 1500m showed higher VO2max and total lap score in the shuttle-run test compared to the athletes living below 1500m. But this difference was found to be statistically insignificant. The Living altitude – VO2max – Total Laps variables had positive moderate correlation each other (r = 0,363, r = 0,355. As the altitude increases, the endurance score increases. When each stage of the shuttle-run test examined, it was seen that those who live at low altitudes tend to give up the shuttle-run test earlier, although there was no difference in the mean heart rates between groups. Findings showed that the physiological response of the biathletes who had similar training history was influenced by the altitude they live on. In this respect, altitude adaptation in biathletes is thought to affect the score in competitions and national team selections.
Rios, Joseph
2016-01-01
Currently, there is no established infrastructure to enable and safely manage the widespread use of low-altitude airspace and UAS flight operations. Given this, and understanding that the FAA faces a mandate to modernize the present air traffic management system through computer automation and significantly reduce the number of air traffic controllers by FY 2020, the FAA maintains that a comprehensive, yet fully automated UAS traffic management (UTM) system for low-altitude airspace is needed. The concept of UTM is to begin by leveraging concepts from the system of roads, lanes, stop signs, rules and lights that govern vehicles on the ground today. Building on its legacy of work in air traffic management (ATM), NASA is working with industry to develop prototype technologies for a UAS Traffic Management (UTM) system that would evolve airspace integration procedures for enabling safe, efficient low-altitude flight operations that autonomously manage UAS operating in an approved low-altitude airspace environment. UTM is a cloud-based system that will autonomously manage all traffic at low altitudes to include UASs being operated beyond visual line of sight of an operator. UTM would thus enable safe and efficient flight operations by providing fully integrated traffic management services such as airspace design, corridors, dynamic geofencing, severe weather and wind avoidance, congestion management, terrain avoidance, route planning re-routing, separation management, sequencing spacing, and contingency management. UTM removes the need for human operators to continuously monitor aircraft operating in approved areas. NASA envisions concepts for two types of UTM systems. The first would be a small portable system, which could be moved between geographical areas in support of operations such as precision agriculture and public safety. The second would be a Persistent system, which would support low-altitude operations in an approved area by providing continuous automated
Neutral barium cloud evolution at different altitudes
International Nuclear Information System (INIS)
Li Lei; Xu Ronglan
2002-01-01
Considering the joint effects of diffusion, collision, oxidation and photoionization, the authors study the evolution of the barium cloud at different altitudes in the space plasma active experiment. The results present the variation of the loss rate, number density distribution and brightness of the barium cloud over the range from 120 to 260 km. This can be divided into oxidation, oxidation plus photoionization and photoionization regions
Mahalingam, Sajeni; McClelland, Grant B; Scott, Graham R
2017-07-15
Mitochondrial function changes over time at high altitudes, but the potential benefits of these changes for hypoxia resistance remains unclear. We used high-altitude-adapted populations of deer mice, which exhibit enhanced aerobic performance in hypoxia, to examine whether changes in mitochondrial physiology or intracellular distribution in the muscle contribute to hypoxia resistance. Permeabilized muscle fibres from the gastrocnemius muscle had higher respiratory capacities in high-altitude mice than in low-altitude mice. Highlanders also had higher mitochondrial volume densities, due entirely to an enriched abundance of subsarcolemmal mitochondria, such that more mitochondria were situated near the cell membrane and adjacent to capillaries. There were several effects of hypoxia acclimation on mitochondrial function, some of which were population specific, but they differed from the evolved changes in high-altitude natives, which probably provide a better indication of adaptive traits that improve performance and hypoxia resistance at high altitudes. High-altitude natives that have evolved to live in hypoxic environments provide a compelling system to understand how animals can overcome impairments in oxygen availability. We examined whether these include changes in mitochondrial physiology or intracellular distribution that contribute to hypoxia resistance in high-altitude deer mice (Peromyscus maniculatus). Mice from populations native to high and low altitudes were born and raised in captivity, and as adults were acclimated to normoxia or hypobaric hypoxia (equivalent to 4300 m elevation). We found that highlanders had higher respiratory capacities in the gastrocnemius (but not soleus) muscle than lowlanders (assessed using permeabilized fibres with single or multiple inputs to the electron transport system), due in large part to higher mitochondrial volume densities in the gastrocnemius. The latter was attributed to an increased abundance of subsarcolemmal
Procedure for altitude compensation for a flame-photometric sulfur analyzer
International Nuclear Information System (INIS)
Hales, J.M.; Easter, R.C.; Lee, R.N.
1979-01-01
A calibration scheme, which applies to the Meloy-285 sulfur analyzer, is described. This scheme allows reliable instrument calibration, which automatically compensates for variations in instrument response with altitude
Sibling Composition and Child Educational Attainment: Evidence from Native Amazonians in Bolivia
Zeng, Wu; Undurraga, Eduardo A.; Eisenberg, Dan T. A.; Rubio-Jovel, Karla; Reyes-Garcia; Victoria; Godoy, Ricardo
2012-01-01
Evidence from industrial nations suggests that sibling composition is associated with children's educational attainment, particularly if parents face resource constraints. If sibling composition is associated with educational attainment, then those associations should be stronger in poor societies of developing nations. We use data from a…
Charles, Mathilde; Corollaro, Maria Laura; Manfrini, Luigi; Endrizzi, Isabella; Aprea, Eugenio; Zanella, Angelo; Corelli Grappadelli, Luca; Gasperi, Flavia
2018-02-01
Texture is important in the preferences of apple consumers. Of the pre-harvest factors affecting fruit quality and especially texture, altitude and subsequent climatic conditions are crucial, determining differences in the physiological mechanisms of fruit growth, ripening stage and chemical composition, as demonstrated by several studies. This work applies a detailed sensory-instrumental protocol developed in a previous paper to investigate the impact of altitude, time of harvest and their cross-effect on sensory characteristics of apple, with a focus on texture. Sensory differences were found in relation to altitude, although the profile results were mainly affected by the time of harvest. Fruit from lower altitude was described as juicier, crunchier and sweeter than samples from higher altitude, which were floury, sourer and more astringent. Texture performance, soluble solids content and titratable acidity corroborated this sensory description. Moreover, anatomical data showed that fruit from lower altitude had a larger volume, a higher number of cells and a higher percentage of intercellular spaces. We demonstrated that differences between fruit from various altitudes can be perceived through human senses, and that the proposed sensory-instrumental tool can be used to describe such differences. This study brings more understanding about the impact of altitude and time of harvest on apple sensory properties. This work could support apple producers, from semi-mountainous regions (Alps, Tyrol, etc.), in advertising and valorising their products with their specific characteristics in a more efficient manner. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.
Chi, Liping
2013-04-01
Although the intergenerational transmission of educational attainment has been confirmed by many researchers, its mechanism still remains controversial. Parent-child communication has been regarded as one of the important mediators. The present study primarily aimed to examine the potentially mediating role of parent-child communication in the transmission of educational attainment, based on a sample of 366 Chinese fifth and sixth graders. Parent-child communication was measured against the three levels of the parents' communication ability, the quality of the father-child and mother-child communications, and the relation between the two dyadic communications. The results duplicated the positive effect of parents' educational attainment on children's academic achievement. Moreover, it was found that parents' communication ability alone played a mediating role, and that the three levels of parent-child communication constructed a "mediator chain" between the parents' educational attainment and the children's academic achievement. Finally, the intergenerational transmission of educational attainment in China and the mediating role of the three levels of parent-child communication were discussed. © 2012 The Institute of Psychology, Chinese Academy of Sciences and Blackwell Publishing Asia Pty Ltd.