Measuring the aerial application of oil dispersant from very large aircraft at moderate altitude

International Nuclear Information System (INIS)

Fay, R.R.; Giammona, C.P.; Binkley, K.; Engelhardt, F.R.

1993-01-01

As part of a study of various aspects of oil dispersant application technology, a comparison study was conducted employing the Airborne Dispersant Delivery System (ADDS) pack and the Modular Aerial Spray System (MASS) in C-130 Hercules aircraft at altitudes of 50-150 ft above ground and at speeds up to 200 knots. Dyed Corexit 9527 was applied at a target dose rate of 5 gal/acre over a collection grid composed of metal trays, Kromekote cards, oil-sensitive cards, a continuous trough, and a WRK string collector. Analysis of the collected dispersant was done by colorimetry, fluorometry, and image analysis. Correlations through the different methodologies demonstrated that high speed, moderate altitude application of oil dispersant could be successful in delivering dispersant to the surface at effective concentration and drop size. Environmental studies of the test area showed no residual dispersant in the soil following cessation of spraying. 1 ref

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

Science.gov (United States)

Ranković, Goran; Radovanović, Dragan

2005-01-01

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

Physiological aspects of altitude training and the use of altitude simulators

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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.

Effects of Dietary Nitrate Supplementation on Physiological Responses, Cognitive Function, and Exercise Performance at Moderate and Very-High Simulated Altitude

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Oliver M. Shannon

2017-06-01

Full Text Available Purpose: Nitric oxide (NO bioavailability is reduced during acute altitude exposure, contributing toward the decline in physiological and cognitive function in this environment. This study evaluated the effects of nitrate (NO3− supplementation on NO bioavailability, physiological and cognitive function, and exercise performance at moderate and very-high simulated altitude.Methods:Ten males (mean (SD: V˙O2max: 60.9 (10.1 ml·kg−1·min−1 rested and performed exercise twice at moderate (~14.0% O2; ~3,000 m and twice at very-high (~11.7% O2; ~4,300 m simulated altitude. Participants ingested either 140 ml concentrated NO3−-rich (BRJ; ~12.5 mmol NO3− or NO3−-deplete (PLA; 0.01 mmol NO3− beetroot juice 2 h before each trial. Participants rested for 45 min in normobaric hypoxia prior to completing an exercise task. Exercise comprised a 45 min walk at 30% V˙O2max and a 3 km time-trial (TT, both conducted on a treadmill at a 10% gradient whilst carrying a 10 kg backpack to simulate altitude hiking. Plasma nitrite concentration ([NO2−], peripheral oxygen saturation (SpO2, pulmonary oxygen uptake (V˙O2, muscle and cerebral oxygenation, and cognitive function were measured throughout.Results: Pre-exercise plasma [NO2−] was significantly elevated in BRJ compared with PLA (p = 0.001. Pulmonary V˙O2 was reduced (p = 0.020, and SpO2 was elevated (p = 0.005 during steady-state exercise in BRJ compared with PLA, with similar effects at both altitudes. BRJ supplementation enhanced 3 km TT performance relative to PLA by 3.8% [1,653.9 (261.3 vs. 1718.7 (213.0 s] and 4.2% [1,809.8 (262.0 vs. 1,889.1 (203.9 s] at 3,000 and 4,300 m, respectively (p = 0.019. Oxygenation of the gastrocnemius was elevated during the TT consequent to BRJ (p = 0.011. The number of false alarms during the Rapid Visual Information Processing Task tended to be lower with BRJ compared with PLA prior to altitude exposure (p = 0.056. Performance in all other cognitive tasks

High altitude headache and acute mountain sickness at moderate elevations in a military population during battalion-level training exercises.

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Norris, Jacob N; Viirre, Erik; Aralis, Hilary; Sracic, Michael K; Thomas, Darren; Gertsch, Jeffery H

2012-08-01

Few studies have evaluated high altitude headache (HAH) and acute mountain sickness (AMS) in military populations training at moderate (1,500-2,500 m) to high altitudes (>2,500 m). In the current study, researchers interviewed active duty personnel training at Marine Corps Mountain Warfare Training Center. Participants were asked about HAH and AMS symptoms, potential risk factors, and medications used. In a sample of 192 U.S. Navy and Marine Corps personnel, 14.6% reported AMS (Lake Louise Criteria > or = 3) and 28.6% reported HAH. Dehydration and recent arrival at altitude (defined as data collected on days 2-3) were significantly associated with AMS; decreased sleep allowance was significantly associated with HAH. Although ibuprofen/Motrin users were more likely to screen positive for AMS, among AMS-positive participants, ibuprofen/Motrin users had decreased likelihood of reporting robust AMS relative to non-ibuprofen/Motrin users (p altitude. Further, ibuprofen/Motrin may be a reasonable treatment for the symptoms of AMS and HAH, although further study is warranted.

Secular trends of physical growth and abdominal adiposity of school children and adolescents living at a moderate altitude in Peru.

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Cossio-Bolaños, Marco; de Arruda, Miguel; Andruske, Cynthia Lee; Luarte-Rocha, Cristian; Gómez-Campos, Rossana

2017-02-01

Identify changes in physical growth and abdominal adiposity at an interval of 14 years in children and adolescents living at a moderate altitude in Peru. The data comes from two cross-sectional studies carried out in the city of Arequipa, Peru, located at a moderate altitude of 2,320 meters. In 2001, 473 males and 482 females were assessed, and in 2015, 432 males and 403 females between 6.0 and 12.9 years old were evaluated. Data were collected in public state schools and measured using the anthropometric variables for weight, height, and waist circumference. Body mass index (BMI) was calculated according to age and sex. Positive trends for weight were identified for both males and females at all ages (p  .05) occurred in height for females between the ages of 6 and 8 years. However, commencing at age 9 until 12 years, females showed positive and significant increases (p Peru. These changes may be associated with the rapid economic development in the country. © 2016 Wiley Periodicals, Inc.

Altitude training improves glycemic control.

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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.

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

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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.

Assessment of oxidative stress biomarkers - neuroprostanes and dihomo-isoprostanes - in the urine of elite triathletes after two weeks of moderate-altitude training.

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García-Flores, Libia Alejandra; Medina, Sonia; Cejuela, Roberto; Martínez-Sanz, José Miguel; Oger, Camille; Galano, Jean-Marie; Durand, Thierry; Casas-Pina, Teresa; Martínez-Hernández, Pedro; Ferreres, Federico; Gil-Izquierdo, Ángel

2016-01-01

This randomized and controlled trial investigated whether the increase in elite training at different altitudes altered the oxidative stress biomarkers of the nervous system. This is the first study to investigate four F4-neuroprostanes (F4-NeuroPs) and four F2-dihomo-isoprostanes (F2-dihomo-IsoPs) quantified in 24-h urine. The quantification was carried out by ultra high pressure liquid chromatography-triple quadrupole-tandem mass spectrometry (UHPLC-QqQ-MS/MS). Sixteen elite triathletes agreed to participate in the project. They were randomized in two groups, a group submitted to altitude training (AT, n = 8) and a group submitted to sea level training (SLT) (n = 8), with a control group (Cg) of non-athletes (n = 8). After the experimental period, the AT group triathletes gave significant data: 17-epi-17-F2t-dihomo-IsoP (from 5.2 ± 1.4 μg/mL 24 h(-1) to 6.6 ± 0.6 μg/mL 24 h(-1)), ent-7(RS)-7-F2t-dihomo-IsoP (from 6.6 ± 1.7 μg/mL 24 h(-1) to 8.6 ± 0.9 μg/mL 24 h(-1)), and ent-7-epi-7-F2t-dihomo-IsoP (from 8.4 ± 2.2 μg/mL 24 h(-1) to 11.3 ± 1.8 μg/mL 24 h(-1)) increased, while, of the neuronal degeneration-related compounds, only 10-epi-10-F4t-NeuroP (8.4 ± 1.7 μg/mL 24 h(-1)) and 10-F4t-NeuroP (5.2 ± 2.9 μg/mL 24 h(-1)) were detected in this group. For the Cg and SLT groups, no significant changes had occurred at the end of the two-week experimental period. Therefore, and as the main conclusion, the training at moderate altitude increased the F4-NeuroPs- and F2-dihomo-isoPs-related oxidative damage of the central nervous system compared to similar training at sea level.

Four Weeks of Classical Altitude Training Increases Resting Metabolic Rate in Highly Trained Middle-Distance Runners.

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Woods, Amy L; Sharma, Avish P; Garvican-Lewis, Laura A; Saunders, Philo U; Rice, Anthony J; Thompson, Kevin G

2017-02-01

High altitude exposure can increase resting metabolic rate (RMR) and induce weight loss in obese populations, but there is a lack of research regarding RMR in athletes at moderate elevations common to endurance training camps. The present study aimed to determine whether 4 weeks of classical altitude training affects RMR in middle-distance runners. Ten highly trained athletes were recruited for 4 weeks of endurance training undertaking identical programs at either 2200m in Flagstaff, Arizona (ALT, n = 5) or 600m in Canberra, Australia (CON, n = 5). RMR, anthropometry, energy intake, and hemoglobin mass (Hb mass ) were assessed pre- and posttraining. Weekly run distance during the training block was: ALT 96.8 ± 18.3km; CON 103.1 ± 5.6km. A significant interaction for Time*Group was observed for absolute (kJ.day -1 ) (F-statistic, p-value: F (1,8) =13.890, p = .01) and relative RMR (F (1,8) =653.453, p = .003) POST-training. No significant changes in anthropometry were observed in either group. Energy intake was unchanged (mean ± SD of difference, ALT: 195 ± 3921kJ, p = .25; CON: 836 ± 7535kJ, p = .75). A significant main effect for time was demonstrated for total Hb mass (g) (F (1,8) =13.380, p = .01), but no significant interactions were observed for either variable [Total Hb mass (g): F (1,8) =1.706, p = .23; Relative Hb mass (g.kg -1 ): F (1,8) =0.609, p = .46]. These novel findings have important practical application to endurance athletes routinely training at moderate altitude, and those seeking to optimize energy management without compromising training adaptation. Altitude exposure may increase RMR and enhance training adaptation,. During training camps at moderate altitude, an increased energy intake is likely required to support an increased RMR and provide sufficient energy for training and performance.

Comparing high altitude treatment with current best care in Dutch children with moderate to severe atopic dermatitis (and asthma): study protocol for a pragmatic randomized controlled trial (DAVOS trial).

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Fieten, Karin B; Zijlstra, Wieneke T; van Os-Medendorp, Harmieke; Meijer, Yolanda; Venema, Monica Uniken; Rijssenbeek-Nouwens, Lous; l'Hoir, Monique P; Bruijnzeel-Koomen, Carla A; Pasmans, Suzanne G M A

2014-03-26

About 10 to 20% of children in West European countries have atopic dermatitis (AD), often as part of the atopic syndrome. The full atopic syndrome also consists of allergic asthma, allergic rhinitis and food allergy. Treatment approaches for atopic dermatitis and asthma include intermittent anti-inflammatory therapy with corticosteroids, health education and self-management training. However, symptoms persist in a subgroup of patients. Several observational studies have shown significant improvement in clinical symptoms in children and adults with atopic dermatitis or asthma after treatment at high altitude, but evidence on the efficacy when compared to treatment at sea level is still lacking. This study is a pragmatic randomized controlled trial for children with moderate to severe AD within the atopic syndrome. Patients are eligible for enrolment in the study if they are: diagnosed with moderate to severe AD within the atopic syndrome, aged between 8 and 18 years, fluent in the Dutch language, have internet access at home, able to use the digital patient system Digital Eczema Center Utrecht (DECU), willing and able to stay in Davos for a six week treatment period. All data are collected at the Wilhelmina Children's Hospital and DECU. Patients are randomized over two groups. The first group receives multidisciplinary inpatient treatment during six weeks at the Dutch Asthma Center in Davos, Switzerland. The second group receives multidisciplinary treatment during six weeks at the outpatient clinic of the Wilhelmina Children's Hospital, Utrecht, the Netherlands. The trial is not conducted as a blind trial. The trial is designed with three components: psychosocial, clinical and translational. Primary outcomes are coping with itch, quality of life and disease activity. Secondary outcomes include asthma control, medication use, parental quality of life, social and emotional wellbeing of the child and translational parameters. The results of this trial will provide

Altitude training considerations for the winter sport athlete.

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

2010-03-01

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

Altitude Training in Elite Swimmers for Sea Level Performance (Altitude Project).

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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.

Hypoxic Hypoxia at Moderate Altitudes: State of the Science

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2011-05-01

nature of cognitive appraisal during exercise in environmentally stressful conditions. Psychology of Sport and Exercise. 2: 47-67. Alpern, M...Shukitt-Hale, B. 1993. Effects of altitude on mood, behaviour and cognitive functioning: A review. Sports Medicine. 16(2): 97-125. Balldin, U...exposure to hypoxia in healthy males [Abstract]. Aviation, Space, and Environmental Medicine. 78(3): 399. Chiles , W. D., Iampietro, P. F. and

Multi-Disciplinary Peer-Mark Moderation of Group Work

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Willmot, Peter; Pond, Keith

2012-01-01

Self and peer assessment offers benefits for enhancing student learning. Peer moderation provides a convenient solution for awarding individual marks in group assignments. This paper provides a significant review of peer-mark moderation, and describes an award winning, web-based tool that was developed in the UK and is now spreading across the…

Year-to-year variability in haemoglobin mass response to two altitude training camps.

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McLean, Blake D; Buttifant, David; Gore, Christopher J; White, Kevin; Kemp, Justin

2013-12-01

To quantify the year-to-year variability of altitude-induced changes in haemoglobin mass (Hb(mass)) in elite team-sport athletes. 12 Australian-Footballers completed a 19-day (ALT1) and 18-day (ALT2) moderate altitude (∼2100 m), training camp separated by 12 months. An additional 20 participants completed only one of the two training camps (ALT1 additional n=9, ALT2 additional n=11). Total Hb(mass) was assessed using carbon monoxide rebreathing before (PRE), after (POST₁) and 4 weeks after each camp. The typical error of Hb(mass) for the pooled data of all 32 participants was 2.6%. A contemporary statistics analysis was used with the smallest worthwhile change set to 2% for Hb(mass). POST₁ Hb(mass) was very likely increased in ALT1 (3.6 ± 1.6%, n=19; mean ± ∼90 CL) as well as ALT2 (4.4 ± 1.3%, n=23) with an individual responsiveness of 1.3% and 2.2%, respectively. There was a small correlation between ALT1 and ALT2 (R=0.21, p=0.59) for a change in Hb(mass), but a moderately inverse relationship between the change in Hb(mass) and initial relative Hb(mass) (g/kg (R=-0.51, p=0.04)). Two preseason moderate altitude camps 1 year apart yielded a similar (4%) mean increase in Hb(mass) of elite footballers, with an individual responsiveness of approximately half the group mean effect, indicating that most players gained benefit. Nevertheless, the same individuals generally did not change their Hb(mass) consistently from year to year. Thus, a 'responder' or 'non-responder' to altitude for Hb(mass) does not appear to be a fixed trait.

ANALYSIS OF ACUTE RESPONSES OF YOUNG BIATHLON ATHLETES LIVING AT DIFFERENT ALTITUDES TO MAXIMAL AEROBIC EXERCISE AT 2000M

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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.

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...

Moderation of Peer Assessment in Group Projects

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Bushell, Graeme

2006-01-01

It is shown here that a grade distribution scheme commonly used to moderate peer assessments where self assessment is excluded is based on a false premise and will give an erroneous ranking in the situation where the best performer in a student group ranks the second best performer much higher than the other group members. An alternative to…

Physiological and performance responses to a preseason altitude-training camp in elite team-sport athletes.

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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.

QT interval changes in term pregnant women living at moderately ...

African Journals Online (AJOL)

Objective: This study aimed to compare the QT interval changes in women with term pregnancy living at moderately high altitude (1890 m in Erzurum, Turkey) with those of women living at sea level (31 m in İstanbul, Turkey). Materials and Methods: One‑hundred ten women (n = 55, for each group) with full‑term and single ...

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

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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.

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

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

2016-02-01

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

Working group on a database for cold moderators

International Nuclear Information System (INIS)

Broome, T. A.

1997-09-01

The working group meeting was chaired by Broome. The working group was charged with the task: Gather a table of neutronic performance known for specific designs; operational, test, theoretical/calculated. Set up generation of a (very briefly) annotated bibliography on this topic. A joint meeting with the Working Group on Moderator Performance Measurements was held to define the data on cold moderators which should be contained in the data base. It became clear that there exists only a small amount of data in very different forms much of it incomplete in its detail. So, rather than spending time collating existing data, it was considered to be more generally profitable to concentrate on the specification of the database and its implementation. The aim was to propose a system which could start quickly and simply yet be capable of extension and development in the future. The system was outlined in the summary session of the workshop and agreed by the participants.

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.

Hemoglobin mass after 21 days of conventional altitude training at 1816 m.

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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.

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

Haematology and erythrocyte metabolism in man at high altitude: an Aymara-Quechua comparison.

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Arnaud, J; Gutierrez, N; Tellez, W; Vergnes, H

1985-07-01

In the course of haematological and biological investigations among Aymara and Quechua populations in Bolivia, an anthropological study of the erythrocytary respiratory function was carried out on the two groups at two altitudes: 3,600 m and 450 m. A difference in the intensity of the biological variations of the two populations is observed at high altitude. In the Quechuas, as in any lowland native, the adaptative phenomena are totally and quickly reversible. In the Aymaras, we detected the existence of more marked haematological and biochemical characters: moderate polycythemia, hyperhaemoglobinemia, microcytosis, metabolical hyperactivity with accumulation of 2-3 di-phosphoglycerate and ATP, and methaemoglobinemia with a drop in the activity of the methaemoglobin reductases. The Aymaras preserve some of those characters (methaemoglobinemia excepted) when they settle in lowlands.

Dietary Recommendations for Cyclists during Altitude Training

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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.

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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.

Respiratory Muscle Training and Cognitive Function Exercising at Altitude.

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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.

Peer Groups as a Context for School Misconduct: The Moderating Role of Group Interactional Style

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Ellis, Wendy; Zarbatany, Lynne; Chen, Xinyin; Kinal, Megan; Boyko, Lisa

2018-01-01

Peer group interactional style was examined as a moderator of the relation between peer group school misconduct and group members' school misconduct. Participants were 705 students (M[subscript age] = 11.59 years, SD = 1.37) in 148 peer groups. Children reported on their school misconduct in fall and spring. In the winter, group members were…

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.

Genotype by environment interaction for growth due to altitude in United States Angus cattle.

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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

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

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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

[Relationship between occupational stress and working ability of workers in a petroleum processing enterprise in high altitude area].

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Ma, X M; Kang, H L; Shi, C B; Li, Y; Wu, Y F; Liu, Z H; Wang, G; Lei, H Y

2017-12-20

Objective: To investigate the relationship between occupational stress and working ability of workers in a petroleum processing enterprise in a high altitude area. Methods: A total of 728 workers in a petroleum processing enterprise at an altitude of 2850 m were subjected to a survey using Occupational Stress Inventory (OSI) , Work Ability Index (WAI) Scale, Occupational Role Questionnaire (ORQ) , Personal Strain Questionnaire (PSQ) , and Personal Resource Questionnaire (PRQ) from May 2014 to August 2016. Results: Of the 728 workers, 55 (7.6%) had a poor working ability, moderate in 262 (35.9%) , and good in 411 (56.5%). There were significant differences in WAI between the workers with different types of work, sexes, ages, and working years ( P occupational stress groups ( P Occupational stress is an influencing factor for the working ability of workers in the petroleum processing enterprise in the high altitude area. Hypoxia in high altitude area may further reduce the working ability. In order to reduce occupational stress and improve work ability, it should be considered to strengthen skills training, improve the working environment, and pay attention to mental health.

Enhancing team-sport athlete performance: is altitude training relevant?

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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.

Preacclimatization in hypoxic chambers for high altitude sojourns.

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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.

Effect of phosphate supplementation on oxygen delivery at high altitude

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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.

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

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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 effect of α1 -adrenergic blockade on post-exercise brachial artery flow-mediated dilatation at sea level and high altitude.

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Tymko, Michael M; Tremblay, Joshua C; Hansen, Alex B; Howe, Connor A; Willie, Chris K; Stembridge, Mike; Green, Daniel J; Hoiland, Ryan L; Subedi, Prajan; Anholm, James D; Ainslie, Philip N

2017-03-01

Our objective was to quantify endothelial function (via brachial artery flow-mediated dilatation) at sea level (344 m) and high altitude (3800 m) at rest and following both maximal exercise and 30 min of moderate-intensity cycling exercise with and without administration of an α 1 -adrenergic blockade. Brachial endothelial function did not differ between sea level and high altitude at rest, nor following maximal exercise. At sea level, endothelial function decreased following 30 min of moderate-intensity exercise, and this decrease was abolished with α 1 -adrenergic blockade. At high altitude, endothelial function did not decrease immediately after 30 min of moderate-intensity exercise, and administration of α 1 -adrenergic blockade resulted in an increase in flow-mediated dilatation. Our data indicate that post-exercise endothelial function is modified at high altitude (i.e. prolonged hypoxaemia). The current study helps to elucidate the physiological mechanisms associated with high-altitude acclimatization, and provides insight into the relationship between sympathetic nervous activity and vascular endothelial function. We examined the hypotheses that (1) at rest, endothelial function would be impaired at high altitude compared to sea level, (2) endothelial function would be reduced to a greater extent at sea level compared to high altitude after maximal exercise, and (3) reductions in endothelial function following moderate-intensity exercise at both sea level and high altitude are mediated via an α 1 -adrenergic pathway. In a double-blinded, counterbalanced, randomized and placebo-controlled design, nine healthy participants performed a maximal-exercise test, and two 30 min sessions of semi-recumbent cycling exercise at 50% peak output following either placebo or α 1 -adrenergic blockade (prazosin; 0.05 mg kg  -1 ). These experiments were completed at both sea-level (344 m) and high altitude (3800 m). Blood pressure (finger photoplethysmography

Acute and Chronic Altitude-Induced Cognitive Dysfunction in Children and Adolescents.

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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.

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 ...

Grappling the High Altitude for Safe Edible Bamboo Shoots with Rich Nutritional Attributes and Escaping Cyanogenic Toxicity

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Sayanika Devi Waikhom

2013-01-01

Full Text Available Consumption of bamboo species with high level of total cyanogenic content (TCC in Asia by many ethnic groups is significantly associated with food poisoning and occasionally Konzo (a neurological disorder. Adequate characterization of edible bamboo species with low level of TCC and high nutritious attributes is required for consumer’s safety as well as for the conservation of the gene pool. Here, we employed morphological descriptors, atomic absorption spectrophotometer, RAPD, and trnL-F intergenic spacer to characterize 15 indigenous edible bamboo species of north-east India. The study indicates that morphologically and genetically evolved edible bamboo species having large and robust bamboo-shoot texture and growing at low altitude contain high level of TCC, low antioxidant properties, and low levels of beneficial macronutrients and micronutrients. Importantly, Dendrocalamus species are shown to be rich in TCC irrespective of the growing altitude while Bambusa species are found to have moderate level of TCC. The findings clearly demonstrated that Chimonobambusa callosa growing at high altitude represents safe edible bamboo species with nutritious attributes.

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

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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.

Left ventricular function during acute high-altitude exposure in a large group of healthy young Chinese men.

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Mingyue Rao

Full Text Available The purpose of this study was to observe left ventricular function during acute high-altitude exposure in a large group of healthy young males.A prospective trial was conducted in Szechwan and Tibet from June to August, 2012. By Doppler echocardiography, left ventricular function was examined in 139 healthy young Chinese men at sea level; within 24 hours after arrival in Lhasa, Tibet, at 3700 m; and on day 7 following an ascent to Yangbajing at 4400 m after 7 days of acclimatization at 3700 m. The resting oxygen saturation (SaO2, heart rate (HR and blood pressure (BP were also measured at the above mentioned three time points.Within 24 hours of arrival at 3700 m, the HR, ejection fraction (EF, fractional shortening (FS, stroke volume (SV, cardiac output (CO, and left ventricular (LV Tei index were significantly increased, but the LV end-systolic dimension (ESD, end-systolic volume (ESV, SaO2, E/A ratio, and ejection time (ET were significantly decreased compared to the baseline levels in all subjects. On day 7 at 4400 m, the SV and CO were significantly decreased; the EF and FS Tei were not decreased compared with the values at 3700 m; the HR was further elevated; and the SaO2, ESV, ESD, and ET were further reduced. Additionally, the E/A ratio was significantly increased on day 7 but was still lower than it was at low altitude.Upon acute high-altitude exposure, left ventricular systolic function was elevated with increased stroke volume, but diastolic function was decreased in healthy young males. With higher altitude exposure and prolonged acclimatization, the left ventricular systolic function was preserved with reduced stroke volume and improved diastolic function.

Levels of protein hydroperoxides and carbonyl groups in guinea pigs native of high altitudes (Huancavelica, 3660 m)

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Huayta, Roxana; Zúñiga, Haydée; Esquerre, Cynthia; Hernández, Luz; Carranza, Elizabeth

2014-01-01

The influence of hypobaric hypoxia on protein oxidation in lungs, heart, liver, kidneys and testicles of high altitude native guinea pigs (Huancavelica, 3660 m) in comparison to sea level (Lima, 150 m) native guinea pigs was evaluated. The concentration of protein hydroperoxides (POOH) and carbonyl groups (GC) as markers of protein oxidation, as well as total thiols (TT) concentration, powerful reducing agents that act as live antioxidants were determined. The results showed low concentration...

Influence of altitude training modality on performance and total haemoglobin mass in elite swimmers.

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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.

HIGH-ALTITUDE ILLNESS

Directory of Open Access Journals (Sweden)

Dwitya Elvira

2015-05-01

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

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

Science.gov (United States)

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

2008-01-01

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

DLR HABLEG- High Altitude Balloon Launched Experimental Glider

Science.gov (United States)

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

2015-09-01

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

The individual response to training and competition at altitude.

Science.gov (United States)

Chapman, Robert F

2013-12-01

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

Respiratory Muscle Training and Exercise Endurance at Altitude.

Science.gov (United States)

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.

Classical altitude training.

Science.gov (United States)

Friedmann-Bette, B

2008-08-01

For more than 40 years, the effects of classical altitude training on sea-level performance have been the subject of many scientific investigations in individual endurance sports. To our knowledge, no studies have been performed in team sports like football. Two well-controlled studies showed that living and training at an altitude of >or=1800-2700 m for 3-4 weeks is superior to equivalent training at sea level in well-trained athletes. Most of the controlled studies with elite athletes did not reveal such an effect. However, the results of some uncontrolled studies indicate that sea-level performance might be enhanced after altitude training also in elite athletes. Whether hypoxia provides an additional stimulus for muscular adaptation, when training is performed with equal intensity compared with sea-level training is not known. There is some evidence for an augmentation of total hemoglobin mass after classical altitude training with duration >or=3 weeks at an altitude >or=2000 m due to altitude acclimatization. Considerable individual variation is observed in the erythropoietic response to hypoxia and in the hypoxia-induced reduction of aerobic performance capacity during training at altitude, both of which are thought to contribute to inter-individual variation in the improvement of sea-level performance after altitude training.

Update in the understanding of altitude-induced limitations to performance in team-sport athletes.

Science.gov (United States)

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.

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...

On-board measurement of particle numbers and their size distribution from a light-duty diesel vehicle: Influences of VSP and altitude.

Science.gov (United States)

Liu, Jia; Ge, Yunshan; Wang, Xin; Hao, Lijun; Tan, Jianwei; Peng, Zihang; Zhang, Chuanzhen; Gong, Huiming; Huang, Ying

2017-07-01

In this study, the particle size-resolved distribution from a China-3 certificated light-duty diesel vehicle was measured by using a portable emission measurement system (PEMS). In order to examine the influences of vehicle specific power (VSP) and high-altitude operation, measurements were conducted at 8 constant speeds, which ranged from 10 to 80km/hr at 10km/hr intervals, and two different high altitudes, namely 2200 and 3200m. The results demonstrated that the numbers of particles in all size ranges decreased significantly as VSP increased when the test vehicle was running at lower speeds (vehicle resulted in increased particle number emissions at low and high driving speeds; however, particle numbers obtained at moderate speeds decreased as altitude rose. When the test vehicle was running at moderate speeds, particle numbers measured at the two altitudes were very close, except for comparatively higher number concentrations of nanoparticles measured at 2200m. Copyright © 2017. Published by Elsevier B.V.

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

Science.gov (United States)

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

2013-01-01

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

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

Science.gov (United States)

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

2013-12-01

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

Physiological aspects of altitude training and the use of altitude simulators

OpenAIRE

Ranković Goran; Radovanović Dragan

2005-01-01

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

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

Science.gov (United States)

Stuber, Thomas; Scherrer, Urs

2010-01-01

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

Athletes at High Altitude.

Science.gov (United States)

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.

Moderate intra-group bias maximizes cooperation on interdependent populations.

Directory of Open Access Journals (Sweden)

Changbing Tang

Full Text Available Evolutionary game theory on spatial structures has received increasing attention during the past decades. However, the majority of these achievements focuses on single and static population structures, which is not fully consistent with the fact that real structures are composed of many interactive groups. These groups are interdependent on each other and present dynamical features, in which individuals mimic the strategy of neighbors and switch their partnerships continually. It is however unclear how the dynamical and interdependent interactions among groups affect the evolution of collective behaviors. In this work, we employ the prisoner's dilemma game to investigate how the dynamics of structure influences cooperation on interdependent populations, where populations are represented by group structures. It is found that the more robust the links between cooperators (or the more fragile the links between cooperators and defectors, the more prevalent of cooperation. Furthermore, theoretical analysis shows that the intra-group bias can favor cooperation, which is only possible when individuals are likely to attach neighbors within the same group. Yet, interestingly, cooperation can be even inhibited for large intra-group bias, allowing the moderate intra-group bias maximizes the cooperation level.

Measurement of the energy spectrum of cosmic-ray induced neutrons aboard an ER-2 high-altitude airplane

CERN Document Server

Goldhagen, P E; Kniss, T; Reginatto, M; Singleterry, R C; Van Steveninck, W; Wilson, J W

2002-01-01

Crews working on present-day jet aircraft are a large occupationally exposed group with a relatively high average effective dose from galactic cosmic radiation. Crews of future high-speed commercial aircraft flying at higher altitudes would be even more exposed. To help reduce the significant uncertainties in calculations of such exposures, the atmospheric ionizing radiation (AIR) project, an international collaboration of 15 laboratories, made simultaneous radiation measurements with 14 instruments on five flights of a NASA ER-2 high-altitude aircraft. The primary AIR instrument was a highly sensitive extended-energy multisphere neutron spectrometer with lead and steel shells placed within the moderators of two of its 14 detectors to enhance response at high energies. Detector responses were calculated for neutrons and charged hadrons at energies up to 100 GeV using MCNPX. Neutron spectra were unfolded from the measured count rates using the new MAXED code. We have measured the cosmic-ray neutron spectrum (t...

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

Science.gov (United States)

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

2013-01-01

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

Consequences of job insecurity and the moderator role of occupational group.

Science.gov (United States)

Sora Miana, Beatriz; González-Morales, M Gloria; Caballer, Amparo; Peiró, José M

2011-11-01

In recent decades, transformations in organizations and the labour market have produced an increase in employee job insecurity. In response to this situation, workers present different negative reactions. However, the intensity of these reactions varies across studies that have investigated the outcomes of job insecurity. One possible explanation for this inconsistency may lie in the influence of other factors, such as the occupational group (Sverke et al., 2002). The aim of this study is to provide additional evidence about the relationship between job insecurity and its outcomes (i.e., life satisfaction, job satisfaction, perceived performance and organizational commitment), and examine the moderator role of occupational group in this relationship. The sample was composed of 321 employees from different Spanish organizations. The results showed that job insecurity was directly and negatively related to life satisfaction, job satisfaction and organizational commitment, and they suggest that occupational group moderated relations between job insecurity and three studied outcomes. In the case of life satisfaction and perceived performance, this relationship was stronger among blue collar workers. The relationship between job insecurity and job satisfaction was stronger in white collar workers. The implications and limitations of this study are discussed.

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

Genomic scan reveals loci under altitude adaptation in Tibetan and Dahe pigs.

Directory of Open Access Journals (Sweden)

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.

Altitude training induced alterations in erythrocyte rheological properties: a controlled comparison study in rats.

Science.gov (United States)

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.

The Effects of Peer-Controlled or Moderated Online Collaboration on Group Problem Solving and Related Attitudes

Directory of Open Access Journals (Sweden)

Ke Zhang

2003-10-01

Full Text Available Abstract. This study investigated the relative benefits of peer-controlled and moderated online collaboration during group problem solving. Thirty-five self-selected groups of four or five students were randomly assigned to the two conditions, which used the same online collaborative tool to solve twelve problem scenarios in an undergraduate statistics course. A score for the correctness of the solutions and a reasoning score were analyzed. A survey was administered to reveal differences in students' related attitudes. Three conclusions were reached: 1. Groups assigned to moderated forums displayed significantly higher reasoning scores than those in the peer-controlled condition, but the moderation did not affect correctness of solutions. 2. Students in the moderated forums reported being more likely to choose to use an optional online forum for future collaborations. 3. Students who reported having no difficulty during collaboration reported being more likely to choose to use an optional online forum in the future.

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

Science.gov (United States)

Butaric, Lauren N; Klocke, Ross P

2018-05-01

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

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

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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.

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

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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.

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

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

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

2010-03-01

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

Maternal and perinatal outcomes in second hemoglobin measurement in nonanemic women at first booking: effect of altitude of residence in peru.

Science.gov (United States)

Gonzales, Gustavo F; Tapia, Vilma; Fort, Alfredo L

2012-01-01

Objective. To determine changes in hemoglobin concentration at second measurements after a normal hemoglobin concentration was detected at first booking during pregnancy at low and at high altitudes. Methods. This is a secondary analysis of a large database obtained from the Perinatal Information System in Peru which includes 379,816 pregnant women and their babies from 43 maternity units in Peru. Results. Most women remained with normal hemoglobin values at second measurement (75.1%). However, 21.4% of women became anemic at the second measurement. In all, 2.8% resulted with moderate/severe anemia and 3.5% with erythrocytosis (Hb>14.5 g/dL). In all cases Hb was higher as altitude increased. Risk for moderate/severe anemia increased associated with higher gestational age at second measurement of hemoglobin, BMI anemia was observed with normal high Hb level at first booking living at moderate and high altitude, and high BMI. Conclusion. Prevalence of anemia increases as pregnancy progress, and that a normal value at first booking may not be considered sufficient as Hb values should be observed throughout pregnancy. BMI was a risk for anemia in a second measurement.

High altitude illness

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

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

Efficacy of Residence at Moderate Versus Low Altitude on Reducing Acute Mountain Sickness in Men Following Rapid Ascent to 4300 m

Science.gov (United States)

2013-01-01

reduced AMS after rapid ascent to high altitude. Key Words: acute mountain sickness, hypobaric hypoxia, acclimatization, fluid balance, ventilatory...response to hypoxia Introduction Altitude acclimatization refers to a series of phys-iologic responses to prolonged exposure to hypobaric hypoxia in low...Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts. 2Center for Aerospace and Hyperbaric Medicine

Increased Hypoxic Dose After Training at Low Altitude with 9h Per Night at 3000m Normobaric Hypoxia.

Science.gov (United States)

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

Brain Food at High Altitude.

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Jain, Vishal

2016-01-01

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

Intergroup Contact Effects via Ingroup Distancing among Majority and Minority Groups: Moderation by Social Dominance Orientation.

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Kauff, Mathias; Schmid, Katharina; Lolliot, Simon; Al Ramiah, Ananthi; Hewstone, Miles

2016-01-01

Five studies tested whether intergroup contact reduces negative outgroup attitudes through a process of ingroup distancing. Based on the deprovincialization hypothesis and Social Dominance Theory, we hypothesized that the indirect effect of cross-group friendship on outgroup attitudes via reduced ingroup identification is moderated by individuals' Social Dominance Orientation (SDO), and occurs only for members of high status majority groups. We tested these predictions in three different intergroup contexts, involving conflictual relations between social groups in Germany (Study 1; N = 150; longitudinal Study 2: N = 753), Northern Ireland (Study 3: N = 160; Study 4: N = 1,948), and England (Study 5; N = 594). Cross-group friendship was associated with reduced ingroup identification and the link between reduced ingroup identification and improved outgroup attitudes was moderated by SDO (the indirect effect of cross-group friendship on outgroup attitudes via reduced ingroup only occurred for individuals scoring high, but not low, in SDO). Although there was a consistent moderating effect of SDO in high-status majority groups (Studies 1-5), but not low-status minority groups (Studies 3, 4, and 5), the interaction by SDO was not reliably stronger in high- than low-status groups. Findings are discussed in terms of better understanding deprovincialization effects of contact.

Intergroup Contact Effects via Ingroup Distancing among Majority and Minority Groups: Moderation by Social Dominance Orientation.

Directory of Open Access Journals (Sweden)

Mathias Kauff

Full Text Available Five studies tested whether intergroup contact reduces negative outgroup attitudes through a process of ingroup distancing. Based on the deprovincialization hypothesis and Social Dominance Theory, we hypothesized that the indirect effect of cross-group friendship on outgroup attitudes via reduced ingroup identification is moderated by individuals' Social Dominance Orientation (SDO, and occurs only for members of high status majority groups. We tested these predictions in three different intergroup contexts, involving conflictual relations between social groups in Germany (Study 1; N = 150; longitudinal Study 2: N = 753, Northern Ireland (Study 3: N = 160; Study 4: N = 1,948, and England (Study 5; N = 594. Cross-group friendship was associated with reduced ingroup identification and the link between reduced ingroup identification and improved outgroup attitudes was moderated by SDO (the indirect effect of cross-group friendship on outgroup attitudes via reduced ingroup only occurred for individuals scoring high, but not low, in SDO. Although there was a consistent moderating effect of SDO in high-status majority groups (Studies 1-5, but not low-status minority groups (Studies 3, 4, and 5, the interaction by SDO was not reliably stronger in high- than low-status groups. Findings are discussed in terms of better understanding deprovincialization effects of contact.

Training at altitude in practice.

Science.gov (United States)

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.

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

Science.gov (United States)

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

2018-01-01

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

Evaluation of transport ventilators at mild simulated altitude: a bench study in a hypobaric chamber.

Science.gov (United States)

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.

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

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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.

Training-dependent cognitive advantage is suppressed at high altitude.

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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.

High-altitude haematology: Quechua-Aymara comparisons.

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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).

The multilevel analysis of surface acting and mental health: A moderation of positive group affective tone

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Lee, Meng-Shiu; Huang, Jui-Chan; Wu, Tzu-Jung

2017-06-01

The purpose of this study is to investigate the relationship among surface acting, mental health, and positive group affective tone. According to the prior theory, this study attempts to establish a comprehensive research framework among these variables, and furthermore tests the moderating effect of positive group affective tone. Data were collected from 435 employees in 52 service industrial companies by questionnaire, and this study conducted multilevel analysis. The results showed that surface acting will negatively affect the mental health. In addition, the positive group affective tone have significant moderating effect on the relationship among surface acting and mental health. Finally, this study discusses managerial implications and highlights future research suggestions.

Altitude and endurance training.

Science.gov (United States)

Rusko, Heikki K; Tikkanen, Heikki O; Peltonen, Juha E

2004-10-01

The benefits of living and training at altitude (HiHi) for an improved altitude performance of athletes are clear, but controlled studies for an improved sea-level performance are controversial. The reasons for not having a positive effect of HiHi include: (1) the acclimatization effect may have been insufficient for elite athletes to stimulate an increase in red cell mass/haemoglobin mass because of too low an altitude (altitude training period (training effect at altitude may have been compromised due to insufficient training stimuli for enhancing the function of the neuromuscular and cardiovascular systems; and (3) enhanced stress with possible overtraining symptoms and an increased frequency of infections. Moreover, the effects of hypoxia in the brain may influence both training intensity and physiological responses during training at altitude. Thus, interrupting hypoxic exposure by training in normoxia may be a key factor in avoiding or minimizing the noxious effects that are known to occur in chronic hypoxia. When comparing HiHi and HiLo (living high and training low), it is obvious that both can induce a positive acclimatization effect and increase the oxygen transport capacity of blood, at least in 'responders', if certain prerequisites are met. The minimum dose to attain a haematological acclimatization effect is > 12 h a day for at least 3 weeks at an altitude or simulated altitude of 2100-2500 m. Exposure to hypoxia appears to have some positive transfer effects on subsequent training in normoxia during and after HiLo. The increased oxygen transport capacity of blood allows training at higher intensity during and after HiLo in subsequent normoxia, thereby increasing the potential to improve some neuromuscular and cardiovascular determinants of endurance performance. The effects of hypoxic training and intermittent short-term severe hypoxia at rest are not yet clear and they require further study.

A Comparitive Analysis of the Influence of Weather on the Flight Altitudes of Birds.

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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.

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

Directory of Open Access Journals (Sweden)

Julio Brito

2018-03-01

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

HIGH ALTITUDES EFFECTS ON HEMATOLOGIC BLOOD PARAMETERS

Directory of Open Access Journals (Sweden)

Hasim Rushiti

2015-05-01

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

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

Science.gov (United States)

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

2014-09-01

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

Variation in aerodynamic coefficients with altitude

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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 ‘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. Keywords: Mach number, Reynolds number, Blunt body, Altitude effect, Angle of attacks

Gokyo Khumbu/Ama Dablam Trek 2012: effects of physical training and high-altitude exposure on oxidative metabolism, muscle composition, and metabolic cost of walking in women.

Science.gov (United States)

Tam, E; Bruseghini, P; Calabria, E; Dal Sacco, L; Doria, C; Grassi, B; Pietrangelo, T; Pogliaghi, S; Reggiani, C; Salvadego, D; Schena, F; Toniolo, L; Verratti, V; Vernillo, G; Capelli, Carlo

2016-01-01

We investigated the effects of moderate-intensity training at low and high altitude on VO2 and QaO2 kinetics and on myosin heavy-chain expression (MyHC) in seven women (36.3 yy ± 7.1; 65.8 kg ± 11.7; 165 cm ± 8) who participated in two 12- to 14-day trekking expeditions at low (598 m) and high altitude (4132 m) separated by 4 months of recovery. Breath-by-breath VO2 and beat-by-beat QaO2 at the onset of moderate-intensity cycling exercise and energy cost of walking (Cw) were assessed before and after trekking. MyHC expression of vastus lateralis was evaluated before and after low-altitude and after high-altitude trekking; muscle fiber high-resolution respirography was performed at the beginning of the study and after high-altitude trekking. Mean response time of VO2 kinetics was faster (P = 0.002 and P = 0.001) and oxygen deficit was smaller (P = 0.001 and P = 0.0004) after low- and high-altitude trekking, whereas ˙ QaO2 kinetics and Cw did not change. Percentages of slow and fast isoforms of MyHC and mitochondrial mass were not affected by low- and high-altitude training. After training altitude, muscle fiber ADP-stimulated mitochondrial respiration was decreased as compared with the control condition (P = 0.016), whereas leak respiration was increased (P = 0.031), leading to a significant increase in the respiratory control ratio (P = 0.016). Although training did not significantly modify muscle phenotype, it induced beneficial adaptations of the oxygen transport-utilization systems witnessed by faster VO2 kinetics at exercise onset.

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

Science.gov (United States)

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

2017-09-01

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

Variation in aerodynamic coefficients with altitude

Science.gov (United States)

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.

High Altitude and Heart

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Murat Yalcin

2011-04-01

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

Acute high-altitude sickness

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Andrew M. Luks

2017-02-01

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

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.

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

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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.

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

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

1986-03-01

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

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

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

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Mukhamed T. Shaov

2018-01-01

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

When Do Low Status Groups Help High Status Groups? The Moderating Effects of Ingroup Identification, Audience Group Membership, and Perceived Reputational Benefit

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Chuma Kevin Owuamalam

2014-11-01

Full Text Available Previous research has demonstrated that, when negative metastereotypes are made salient, members of low status groups help members of high status groups in order to improve the reputation of their low status group and its associated social identity. The present research investigated three potential moderators of low status groups’ outgroup helping: ingroup identification, audience group membership, and perceived reputational benefit. In Study 1 (N = 112 we found that members of a low status group (Keele University students were most likely to offer to help raise funds for a high status group (University of Birmingham students when they were high identifiers who had considered a negative metastereotype and believed that their responses would be viewed by an outgroup member. In Study 2 (N = 100 we found a similar effect in an intergroup context that referred to psychology students (low status ingroup and junior doctors (high status outgroup, showing that the effect was limited to people who perceived reputational benefit in helping the outgroup. The practical and social implications of these findings are discussed in relation to intergroup contact and international relations.

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.

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

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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.

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

Effects of repetitive training at low altitude on erythropoiesis in 400 and 800 m runners.

Science.gov (United States)

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.

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

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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.

Altitude Stress During Participation of Medical Congress

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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.

Science.gov (United States)

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.

Corona Onset Characteristics of Bundle Conductors in UHV AC Power Lines at 2200 m Altitude

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Shilong Huang

2018-04-01

Full Text Available The corona onset characteristic of bundle conductors is an important limiting factor for the design of UHV AC power lines in high-altitude areas. An experimental study on the corona characteristics of 8 × LGJ630, 6 × LGJ720, 8 × LGJ720 and 10 × LGJ720 bundle conductors commonly used in UHV power lines under dry and wet conductor conditions, as well as artificial moderate and heavy rain conditions, was conducted in Ping’an County, Xining City (elevation 2200 m. By using the tangent line method, the corona onset voltages and onset electric field of four types of conductors at high altitudes are obtained for the first time. In addition, the calculation model of corona onset voltage considering the outer strands’ effect on the electric field and the geometric factor in the corona cage in high altitude areas is established. The comparison of the calculation results and experimental results under dry conditions verifies the model’s correctness. Based on the results, an optimal selection scheme for high altitudes is proposed. The roughness coefficient was also calculated and analysed: the roughness coefficient of bundled conductors was between 0.59 and 0.77, and the roughness coefficient of the wet conductor was between the dry and rainy conditions. Both the experimental data and the calculation model can provide a reference for conductor selection for UHV AC power lines for use in high-altitude areas.

High altitude induced anorexia: effect of changes in leptin and oxidative stress levels.

Science.gov (United States)

Vats, Praveen; Singh, Vijay Kumar; Singh, Som Nath; Singh, Shashi Bala

2007-01-01

High altitude (HA) exposure usually leads to a significant weight loss in non-acclimatized humans. Anorexia is believed to be the main cause of this body weight loss. Appetite regulatory peptides, i.e. leptin and neuropeptide Y play a key role in food intake and energy homeostasis. Recent studies suggests increased oxidative stress during HA exposure. In present study effect of HA exposure on levels of leptin and NPY was evaluated along with N-acetyl cysteine (NAC) and vitamin E supplementation in relation to food intake and body weight changes. The study was conducted on 30 healthy male volunteers (age 19-29 years). Subjects were divided randomly into three groups of 10 each. Group 1 (placebo) supplemented with 400 mg of calcium gluconate, group 2 and 3 were supplemented with 400 mg of NAC and 400 mg vitamin E, respectively per day. The study was conducted at low altitude (320 m, Phase I), at HA 3600 m (Phase II) and at an altitude of 4580 m (Phase III). On HA exposure significant reduction in plasma leptin levels was observed in all the groups on day 2 (Phase II) along with decrease in food intake and reduction in body weight. Statistically significant increase in blood malondialdehyde (MDA) levels was seen in all the groups on HA exposure (Phase II, Day 2), but the maximum increase was in case of placebo group (65.1%) on day 2 (Phase II) in comparison to low altitude values. The decrease in energy intake was almost same in all the groups indicating that antioxidant supplementation did not provide any protection against HA anorexia. From the study, it may be concluded that leptin and oxidative stress possibly are not the key players for HA anorexia.

RaD-X: Complementary measurements of dose rates at aviation altitudes

Science.gov (United States)

Meier, Matthias M.; Matthiä, Daniel; Forkert, Tomas; Wirtz, Michael; Scheibinger, Markus; Hübel, Robert; Mertens, Christopher J.

2016-09-01

The RaD-X stratospheric balloon flight organized by the National Aeronautics and Space Administration was launched from Fort Sumner on 25 September 2015 and carried several instruments to measure the radiation field in the upper atmosphere at the average vertical cutoff rigidity Rc of 4.1 GV. The German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt) in cooperation with Lufthansa German Airlines supported this campaign with an independent measuring flight at the altitudes of civil aviation on a round trip from Germany to Japan. The goal was to measure dose rates under similar space weather conditions over an area on the Northern Hemisphere opposite to the RaD-X flight. Dose rates were measured in the target areas, i.e., around vertical cutoff rigidity Rc of 4.1 GV, at two flight altitudes for about 1 h at each position with acceptable counting statistics. The analysis of the space weather situation during the flights shows that measuring data were acquired under stable and moderate space weather conditions with a virtually undisturbed magnetosphere. The measured rates of absorbed dose in silicon and ambient dose equivalent complement the data recorded during the balloon flight. The combined measurements provide a set of experimental data suitable for validating and improving numerical models for the calculation of radiation exposure at aviation altitudes.

Cardiovascular Effects of Altitude on Performance Athletes.

Science.gov (United States)

Shah, Ankit B; Coplan, Neil

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

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

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Qi-quan ZHOU

2012-02-01

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

Altitude Lab

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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

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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.

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

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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.

The STAR Data Reporting Guidelines for Clinical High Altitude Research.

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

2018-03-01

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

Changes in Running Economy, Respiratory Exchange Ratio and VO2max in Runners following a 10-day Altitude Training Camp.

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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.

Introduction to altitude/hypoxic training symposium.

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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.

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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.

High Altitude Launch for a Practical SSTO

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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).

Determinants of team-sport performance: implications for altitude training by team-sport athletes

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Bishop, David J; Girard, Olivier

2013-01-01

Team sports are increasingly popular, with millions of participants worldwide. Athletes engaged in these sports are required to repeatedly produce skilful actions and maximal or near-maximal efforts (eg, accelerations, changes in pace and direction, sprints, jumps and kicks), interspersed with brief recovery intervals (consisting of rest or low-intensity to moderate-intensity activity), over an extended period of time (1–2 h). While performance in most team sports is dominated by technical and tactical proficiencies, successful team-sport athletes must also have highly-developed, specific, physical capacities. Much effort goes into designing training programmes to improve these physical capacities, with expected benefits for team-sport performance. Recently, some team sports have introduced altitude training in the belief that it can further enhance team-sport physical performance. Until now, however, there is little published evidence showing improved team-sport performance following altitude training, despite the often considerable expense involved. In the absence of such studies, this review will identify important determinants of team-sport physical performance that may be improved by altitude training, with potential benefits for team-sport performance. These determinants can be broadly described as factors that enhance either sprint performance or the ability to recover from maximal or near-maximal efforts. There is some evidence that some of these physical capacities may be enhanced by altitude training, but further research is required to verify that these adaptations occur, that they are greater than what could be achieved by appropriate sea-level training and that they translate to improved team-sport performance. PMID:24282200

Determinants of team-sport performance: implications for altitude training by team-sport athletes.

Science.gov (United States)

Bishop, David J; Girard, Olivier

2013-12-01

Team sports are increasingly popular, with millions of participants worldwide. Athletes engaged in these sports are required to repeatedly produce skilful actions and maximal or near-maximal efforts (eg, accelerations, changes in pace and direction, sprints, jumps and kicks), interspersed with brief recovery intervals (consisting of rest or low-intensity to moderate-intensity activity), over an extended period of time (1-2 h). While performance in most team sports is dominated by technical and tactical proficiencies, successful team-sport athletes must also have highly-developed, specific, physical capacities. Much effort goes into designing training programmes to improve these physical capacities, with expected benefits for team-sport performance. Recently, some team sports have introduced altitude training in the belief that it can further enhance team-sport physical performance. Until now, however, there is little published evidence showing improved team-sport performance following altitude training, despite the often considerable expense involved. In the absence of such studies, this review will identify important determinants of team-sport physical performance that may be improved by altitude training, with potential benefits for team-sport performance. These determinants can be broadly described as factors that enhance either sprint performance or the ability to recover from maximal or near-maximal efforts. There is some evidence that some of these physical capacities may be enhanced by altitude training, but further research is required to verify that these adaptations occur, that they are greater than what could be achieved by appropriate sea-level training and that they translate to improved team-sport performance.

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

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

2013-01-01

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

Moderators of the effects of group-based physical exercise on cancer survivors' quality of life

NARCIS (Netherlands)

Kalter, Joeri; Buffart, Laurien M.; Korstjens, Irene; van Weert, Ellen; Brug, Johannes; Verdonck-de Leeuw, Irma M.; Mesters, Ilse; van den Borne, Bart; Hoekstra-Weebers, Josette E. H. M.; Ros, Wynand J. G.; May, Anne M.

This study explored demographic, clinical, and psychological moderators of the effect of a group-based physical exercise intervention on global quality of life (QoL) among cancer survivors who completed treatment. Cancer survivors were assigned to a 12-week physical exercise (n = 147) or a wait-list

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

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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.

Science.gov (United States)

West, John B

2016-02-01

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

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

Reducing pulmonary injury by hyperbaric oxygen preconditioning during simulated high altitude exposure in rats.

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Li, Zhuo; Gao, Chunjin; Wang, Yanxue; Liu, Fujia; Ma, Linlin; Deng, Changlei; Niu, Ko-Chi; Lin, Mao-Tsun; Wang, Chen

2011-09-01

Hyperbaric oxygen preconditioning (HBO₂P + HAE) has been found to be beneficial in preventing the occurrence of ischemic damage to brain, spinal cord, heart, and liver in several disease models. In addition, pulmonary inflammation and edema are associated with a marked reduction in the expression levels of both aquaporin (AQP) 1 and AQP5 in the lung. Here, the aims of this study are first to ascertain whether acute lung injury can be induced by simulated high altitude in rats and second to assess whether HBO2P + HAE is able to prevent the occurrence of the proposed high altitude-induced ALI. Rats were randomly divided into the following three groups: the normobaric air (NBA; 21% O₂ at 1 ATA) group, the HBO₂P + high altitude exposure (HAE) group, and the NBA + HAE group. In HBO₂P + HAE group, animals received 100% O₂ at 2.0 ATA for 1 hour per day, for five consecutive days. In HAE groups, animals were exposed to a simulated HAE of 6,000 m in a hypobaric chamber for 24 hours. Right after being taken out to the ambient, animals were anesthetized generally and killed and thoroughly exsanguinated before their lungs were excised en bloc. The lungs were used for both histologic and molecular evaluation and analysis. In NBA + HAE group, the animals displayed higher scores of alveolar edema, neutrophil infiltration, and hemorrhage compared with those of NBA controls. In contrast, the levels of both AQP1 and AQP5 proteins and mRNA expression in the lung in the NBA + HAE group were significantly lower than those of NBA controls. However, the increased lung injury scores and the decreased levels of both AQP1 and AQP5 proteins and mRNA expression in the lung caused by HAE was significantly reduced by HBO₂P + HAE. Our results suggest that high altitude pulmonary injury may be prevented by HBO2P + HAE in rats.

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

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Eduardo Borba Neves

2017-11-01

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

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

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Tolga Saka

2017-03-01

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

Altitude Compensating Nozzle

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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.

Do client attributes moderate the effectiveness of a group cognitive behavioral therapy for depression in addiction treatment?

Science.gov (United States)

Hunter, Sarah B; Paddock, Susan M; Zhou, Annie; Watkins, Katherine E; Hepner, Kimberly A

2013-01-01

The study goal was to determine whether client attributes were associated with outcomes from group cognitive behavioral therapy for depression (GCBT-D) as delivered in community-based addiction treatment settings. Data from 299 depressed residential clients assigned to receive either usual care (N = 159) or usual care plus GCBT-D (N = 140) were examined. Potential moderators included gender, race/ethnicity, education, referral status, and problem substance use. Study outcomes at 6 months post-baseline included changes in depressive symptoms, mental health functioning, negative consequences from substance use, and percentage of days abstinent. Initial examination indicated that non-Hispanic Whites had significantly better outcomes than other racial/ethnic groups on two of the four outcomes. After correcting for multiple testing, none of the examined client attributes moderated the treatment effect. GCBT-D appears effective; however, the magnitude and consistency of treatment effects indicate that it may be less helpful among members of racial/ethnic minority groups and is worthy of future study.

Perceived Ethnic Discrimination and Problem Behaviors in Muslim Immigrant Early Adolescents: Moderating Effects of Ethnic, Religious, and National Group Identification

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Maes, Marlies; Stevens, Gonneke W. J. M.; Verkuyten, Maykel

2014-01-01

Previous research has identified ethnic group identification as a moderator in the relationship between perceived ethnic discrimination and problem behaviors in ethnic minority children. However, little is known about the influence of religious and host national identification on this relationship. This study investigated the moderating role of…

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

Directory of Open Access Journals (Sweden)

Ling LI

2016-10-01

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

Intra-Group Conflict and Teamwork Quality: The Moderating Role of Leadership Styles

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Petru L. Curşeu

2011-03-01

Full Text Available The study examines the extent to which task and relations oriented leadership moderate the impact of task and relationship conflict on teamwork quality. In a sample of 37 teams, the study shows that relationship oriented leadership is beneficial for dealing with relationship conflict, but it does not have the expected positive interaction effect with task conflict. The main practical implication of the results is that in order to mitigate the negative effects of intra-group conflict on teamwork quality the leadership style should fit the type of disagreement (task versus relational predominantly experienced by the teams.

Interviewing the moderator

DEFF Research Database (Denmark)

Traulsen, Janine Morgall; Almarsdóttir, Anna Birna; Björnsdóttir, Ingunn

2004-01-01

There has been an upsurge of academic interest in using focus groups (FGs) as a main or stand-alone qualitative method. In this article, the authors introduce a recently developed ancillary method to FGs called interviewing the moderator. The method is employed immediately after an FG and consists...... of a one-on-one interview with the FG moderator by another member of the research team. The authors argue, with reference to a specific study, that interviewing the moderator adds a new and valuable dimension to group interviews used in research. They describe how this method came about and provide...

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

International Nuclear Information System (INIS)

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

1984-01-01

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

Increased Hypoxic Dose After Training at Low Altitude with 9h Per Night at 3000m Normobaric Hypoxia

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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.

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

International Nuclear Information System (INIS)

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

1998-01-01

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

Shilajit: A panacea for high-altitude problems.

Science.gov (United States)

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.

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

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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.

System for indicating fuel-efficient aircraft altitude

Science.gov (United States)

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.

The Effect of Natural or Simulated Altitude Training on High-Intensity Intermittent Running Performance in Team-Sport Athletes: A Meta-Analysis.

Science.gov (United States)

Hamlin, Michael J; Lizamore, Catherine A; Hopkins, Will G

2018-02-01

While adaptation to hypoxia at natural or simulated altitude has long been used with endurance athletes, it has only recently gained popularity for team-sport athletes. To analyse the effect of hypoxic interventions on high-intensity intermittent running performance in team-sport athletes. A systematic literature search of five journal databases was performed. Percent change in performance (distance covered) in the Yo-Yo intermittent recovery test (level 1 and level 2 were used without differentiation) in hypoxic (natural or simulated altitude) and control (sea level or normoxic placebo) groups was meta-analyzed with a mixed model. The modifying effects of study characteristics (type and dose of hypoxic exposure, training duration, post-altitude duration) were estimated with fixed effects, random effects allowed for repeated measurement within studies and residual real differences between studies, and the standard-error weighting factors were derived or imputed via standard deviations of change scores. Effects and their uncertainty were assessed with magnitude-based inference, with a smallest important improvement of 4% estimated via between-athlete standard deviations of performance at baseline. Ten studies qualified for inclusion, but two were excluded owing to small sample size and risk of publication bias. Hypoxic interventions occurred over a period of 7-28 days, and the range of total hypoxic exposure (in effective altitude-hours) was 4.5-33 km h in the intermittent-hypoxia studies and 180-710 km h in the live-high studies. There were 11 control and 15 experimental study-estimates in the final meta-analysis. Training effects were moderate and very likely beneficial in the control groups at 1 week (20 ± 14%, percent estimate, ± 90% confidence limits) and 4-week post-intervention (25 ± 23%). The intermittent and live-high hypoxic groups experienced additional likely beneficial gains at 1 week (13 ± 16%; 13 ± 15%) and 4-week post

Regulation of human skeletal muscle perfusion and its heterogeneity during exercise in moderate hypoxia

DEFF Research Database (Denmark)

Heinonen, Ilkka H; Kemppainen, Jukka; Kaskinoro, Kimmo

2010-01-01

, the results show that increased BF during one-leg exercise in moderate hypoxia is confined only to the contracting muscles, and the working muscle hyperemia appears not to be directly mediated by adenosine. Increased flow heterogeneity in noncontracting muscles likely reflects sympathetic nervous constraints...... healthy young men using positron emission tomography during one-leg dynamic knee extension exercise in normoxia and moderate physiological systemic hypoxia (14% O(2) corresponding to approximately 3,400 m of altitude) without and with local adenosine receptor inhibition with femoral artery infusion...... to curtail BF increments in areas other than working skeletal muscles, but this effect is not potentiated in moderate systemic hypoxia during small muscle mass exercise....

Application of altitude/hypoxic training by elite athletes.

Science.gov (United States)

Wilber, Randall L

2007-09-01

At the Olympic level, differences in performance are typically less than 0.5%. This helps explain why many contemporary elite endurance athletes in summer and winter sport incorporate some form of altitude/hypoxic training within their year-round training plan, believing that it will provide the "competitive edge" to succeed at the Olympic level. The purpose of this paper is to describe the practical application of altitude/hypoxic training as used by elite athletes. Within the general framework of the paper, both anecdotal and scientific evidence will be presented relative to the efficacy of several contemporary altitude/hypoxic training models and devices currently used by Olympic-level athletes for the purpose of legally enhancing performance. These include the three primary altitude/hypoxic training models: 1) live high+train high (LH+TH), 2) live high+train low (LH+TL), and 3) live low+train high (LL+TH). The LH+TL model will be examined in detail and will include its various modifications: natural/terrestrial altitude, simulated altitude via nitrogen dilution or oxygen filtration, and hypobaric normoxia via supplemental oxygen. A somewhat opposite approach to LH+TL is the altitude/hypoxic training strategy of LL+TH, and data regarding its efficacy will be presented. Recently, several of these altitude/hypoxic training strategies and devices underwent critical review by the World Anti-Doping Agency (WADA) for the purpose of potentially banning them as illegal performance-enhancing substances/methods. This paper will conclude with an update on the most recent statement from WADA regarding the use of simulated altitude devices.

Can High Altitude Influence Cytokines and Sleep?

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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?

Science.gov (United States)

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

2013-01-01

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

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 ...

Reciprocal Relations between Student-Teacher Relationship and Children's Behavioral Problems: Moderation by Child-Care Group Size

Science.gov (United States)

Skalická, Vera; Belsky, Jay; Stenseng, Frode; Wichstrøm, Lars

2015-01-01

In this Norwegian study, bidirectional relations between children's behavior problems and child-teacher conflict and closeness were examined, and the possibility of moderation of these associations by child-care group size was tested. Eight hundred and nineteen 4-year-old children were followed up in first grade. Results revealed reciprocal…

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.

Moderators of the Effects of Indicated Group and Bibliotherapy Cognitive Behavioral Depression Prevention Programs on Adolescents’ Depressive Symptoms and Depressive Disorder Onset

Science.gov (United States)

Müller, Sina; Rohde, Paul; Gau, Jeff M.; Stice, Eric

2015-01-01

We investigated factors hypothesized to moderate the effects of cognitive behavioral group-based (CB group) and bibliotherapy depression prevention programs. Using data from two trials (N = 631) wherein adolescents (M age = 15.5, 62% female, 61% Caucasian) with depressive symptoms were randomized into CB group, CB bibliotherapy, or an educational brochure control condition, we evaluated the moderating effects of individual, demographic, and environmental factors on depressive symptom reductions and major depressive disorder (MDD) onset over 2-year follow-up. CB group and bibliotherapy participants had lower depressive symptoms than controls at posttest but these effects did not persist. No MDD prevention effects were present in the merged data. Relative to controls, elevated depressive symptoms and motivation to reduce depression amplified posttest depressive symptom reduction for CB group, and elevated baseline symptoms amplified posttest symptom reduction effects of CB bibliotherapy. Conversely, elevated substance use mitigated the effectiveness of CB group relative to controls on MDD onset over follow-up. Findings suggest that both CB prevention programs are more beneficial for youth with at least moderate depressive symptoms, and that CB group is more effective for youth motivated to reduce their symptoms. Results also imply that substance use reduces the effectiveness of CB group-based depression prevention. PMID:26480199

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.

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

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.

Reducing body fat with altitude hypoxia training in swimmers: role of blood perfusion to skeletal muscles.

Science.gov (United States)

Chia, Michael; Liao, Chin-An; Huang, Chih-Yang; Lee, Wen-Chih; Hou, Chien-Wen; Yu, Szu-Hsien; Harris, M Brennan; Hsu, Tung-Shiung; Lee, Shin-Da; Kuo, Chia-Hua

2013-02-28

Swimmers tend to have greater body fat than athletes from other sports. The purpose of the study was to examine changes in body composition after altitude hypoxia exposure and the role of blood distribution to the skeletal muscle in swimmers. With a constant training volume of 12.3 km/day, young male swimmers (N = 10, 14.8 ± 0.5 years) moved from sea-level to a higher altitude of 2,300 meters. Body composition was measured before and after translocation to altitude using dual-energy X-ray absorptiometry (DXA) along with 8 control male subjects who resided at sea level for the same period of time. To determine the effects of hypoxia on muscle blood perfusion, total hemoglobin concentration (THC) was traced by near-infrared spectroscopy (NIRS) in the triceps and quadriceps muscles under glucose-ingested and insulin-secreted conditions during hypoxia exposure (16% O2) after training. While no change in body composition was found in the control group, subjects who trained at altitude had unequivocally decreased fat mass (-1.7 ± 0.3 kg, -11.4%) with increased lean mass (+0.8 ± 0.2 kg, +1.5%). Arterial oxygen saturation significantly decreased with increased plasma lactate during hypoxia recovery mimicking 2,300 meters at altitude (~93% versus ~97%). Intriguingly, hypoxia resulted in elevated muscle THC, and sympathetic nervous activities occurred in parallel with greater-percent oxygen saturation in both muscle groups. In conclusion, the present study provides evidence that increased blood distribution to the skeletal muscle under postprandial condition may contribute to the reciprocally increased muscle mass and decreased body mass after a 3-week altitude exposure in swimmers.

Comparison of an Intermittent Hypoxic Exposure Acclimatization Program to Staging at Moderate Altitude on Endurance Performance at 4300 m

Science.gov (United States)

2009-10-01

Endurance Performance at 4300 m 7 - 6 RTO-MP-HFM-181 breakfast volunteers were provided with two commercially available energy bars and fruit juice ...food composition = 510 kcal, 14 gm fat, 65 gm carbohydrate, 32 gm protein) at 1 to 2 hrs prior to the beginning of each of the cycle endurance test...JE, Robinson SR, Skrinar GS, Lewis SF and Sawka MN. Intermittent altitude exposures improve muscular performance at 4,300 m. J Appl Physiol 95

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

Science.gov (United States)

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.

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)

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....

Effects of high altitude training on exercise capacity: fact or myth.

Science.gov (United States)

de Paula, Paula; Niebauer, Josef

2012-03-01

High altitude training has become a mainstay in endurance sports, with live high-train low as the current protocol of choice. Athletes either live or sleep in artificial or natural hypoxic conditions with the aim to increase serum erythropoietin concentrations, which are thought to improve maximum oxygen uptake and thus exercise performance. Changes, however, are not very striking and only apparent in so-called responders, who are not a well-defined group and may be as little as 50% of the trained study population. Whereas some studies show minor improvement, others report no change or even worsening. Furthermore, the mechanisms behind the proposed beneficial changes remain obscure and are far from being proven. There is an evident lack of sufficiently powered randomized, double-blinded studies, with training protocols that are identical for all groups and groups that are indeed comparable. Several studies discriminate between responders and non-responders, without clearly assessing the characteristics of the so-called responders. Until this has been done, it remains unclear if such a group really exists and how these subjects are characterized. This, however, would be of immense value, so protocols could be tailored to athletes' needs. Taken together, the current literature on natural or artificial hypoxia somewhat documents improved performance at high but not low altitude.

The impact of social value orientation on affective commitment : The moderating role of work group cooperative climate, and of climate strength

NARCIS (Netherlands)

Bogaert, S.; Boone, Chr.; van Witteloostuijn, A.

2012-01-01

We investigate the moderating role of an individual's social value orientation (which refers to self- versus other-regarding preferences) and of climate strength (which refers to the extent of agreement among group members on group norms and values) on the relationship between work group cooperative

Serum immunoreactive erythropoietin in high altitude natives with and without excessive erythrocytosis.

Science.gov (United States)

León-Velarde, F; Monge, C C; Vidal, A; Carcagno, M; Criscuolo, M; Bozzini, C E

1991-05-01

We report the estimation of blood hemoglobin (Hb), arterial blood oxygen saturation (SaO2), and serum immunoreactive erythropoietin (siEPO) in a group of Peruvian workers residing in Cerro de Pasco at 4300 m showing "excessive erythrocytosis" (EE, Monge's disease, chronic mountain sickness). These estimates were compared with those of humans residing either in Cerro de Pasco and showing "normal erythrocytosis" (NE) or in Lima (sea level, SL) to determine whether Hb and SaO2 are related to siEPO in high altitude (HA) natives with NE or EE. The three parameters showed statistically significant differences between HA and SL groups--the values in SL being lower. Significant differences were also found between NE and EE groups in Hb and SaO2. There was no statistical difference in siEPo between the two groups. The results indicate, therefore, that HA residents who develop EE are not distinguishable from residents who develop NE on the basis of estimates of siEPO. As a result, siEPO and Hb do not show a dose-response relationship in HA residents, and variation in EPO does not explain the striking variation in Hb at high altitudes.

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

DEFF Research Database (Denmark)

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

2015-01-01

The impact of altitude training on haematological parameters and the Athlete Biological Passport (ABP) was evaluated in international-level elite athletes. One group of swimmers lived high and trained high (LHTH, n = 10) for three to four weeks at 2130 m or higher whereas a control group (n = 10......) 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...

Relationship Between Vertical Jump Height and Swimming Start Performance Before and After an Altitude Training Camp.

Science.gov (United States)

García-Ramos, Amador; Padial, Paulino; de la Fuente, Blanca; Argüelles-Cienfuegos, Javier; Bonitch-Góngora, Juan; Feriche, Belén

2016-06-01

This study aimed (a) to analyze the development in the squat jump height and swimming start performance after an altitude training camp, (b) to correlate the jump height and swimming start performance before and after the altitude training period, and (c) to correlate the percent change in the squat jump height with the percent change in swimming start performance. Fifteen elite male swimmers from the Spanish Junior National Team (17.1 ± 0.8 years) were tested before and after a 17-day training camp at moderate altitude. The height reached in the squat jump exercise with additional loads of 0, 25, 50, 75, and 100% of swimmers' pretest body weight and swimming start performance (time to 5, 10, and 15 m) were the dependent variables analyzed. Significant increases in the jump height (p ≤ 0.05; effect size [ES]: 0.35-0.48) and swimming start performance (p jump height before training (r = -0.56 to -0.77) and after training (r = -0.50 to -0.71). The change in the squat jump height was inversely correlated with the change in the start time at 5 m (r = -0.47), 10 m (r = -0.73), and 15 m (r = -0.62). These results suggest that altitude training can be suitable to enhance explosive performance. The correlations obtained between the squat jump height and start time in the raw and change scores confirm the relevance of having high levels of lower-body muscular power to optimize swimming start performance.

HIGH ALTITUDES EFFECTS ON HEMATOLOGIC BLOOD PARAMETERS

OpenAIRE

Hasim Rushiti; Florian Miftari; Besim Halilaj

2015-01-01

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

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

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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.

Improving estimation of flight altitude in wildlife telemetry studies

Science.gov (United States)

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.

Myocellular limitations of human performance and their modification through genome-dependent responses at altitude.

Science.gov (United States)

Flueck, Martin

2010-03-01

Human muscle operates along a continuum of power output, which is set through bioenergetic and anatomical principles. In turn, environmental and intrinsic factors during contractile work exert pronounced control over muscle performance by instructing muscle remodelling. This phenotypic control is specifically indicated with intense exercise at altitude, when extra strain is put on energy supply and the temperature-dependent mechanical efficiency of contraction. While it is classically thought that chronic exposure to hypoxia is maladaptive, repeated short episodes of reduced oxygenation alone or in combination with intense endurance work is now understood to preserve exercise performance when atmospheric oxygen levels are low. Endurance training at moderate altitude exploits the temperature-dependent malleability of energy supply that may maximize metabolic flux at altitude. The contribution of genomic mechanisms is important to the plasticity of metabolic pathways in exercised muscle. This is highlighted by the association of distinct gene polymorphisms in master governors of mitochondrial and vascular growth with exercise phenotypes. Feedforward control of human locomoter muscle by exercise involves the transient upregulation of transcript expression for metabolic processes. The response of the mitochondrial transcriptome to intense exercise is graded with respect to mitochondrial content and deoxygenation during muscle work and reflects exercise-induced mitochondrial biogenesis. This supports the notion that genome-mediated muscle malleability is under feedback control by design constraints of the pathway of oxygen. Thus, activity-dependent and genetic mechanisms contribute to the interindividual difference in the metabolic bottlenecks in athletes performing in exceptional environmental conditions.

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

Science.gov (United States)

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

2018-03-04

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

Pressure breathing in fighter aircraft for G accelerations and loss of cabin pressurization at altitude--a brief review.

Science.gov (United States)

Lauritzsen, Lars P; Pfitzner, John

2003-04-01

The purpose of this brief review is to outline the past and present use of pressure breathing, not by patients but by fighter pilots. Of the historical and recent references quoted, most are from aviation-medicine journals that are not often readily available to anesthesiologists. Pressure breathing at moderate levels of airway pressure gave World War II fighter pilots a tactical altitude advantage. With today's fast and highly maneuverable jet fighters, very much higher airway pressures of the order of 8.0 kPa (identical with 60 mmHg) are used. They are used in conjunction with a counterpressure thoracic vest and an anti-G suit for the abdomen and lower body. Pressurization is activated automatically in response to +Gz accelerations, and to a potentially catastrophic loss of cabin pressurization at altitude. During +Gz accelerations, pressure breathing has been shown to maintain cerebral perfusion by raising the systemic arterial pressure, so increasing the level of G-tolerance that is afforded by the use of anti-G suits and seat tilt-back angles alone. This leaves the pilot less reliant on rigorous, and potentially distracting, straining maneuvers. With loss of cabin pressurization at altitude, pressure breathing of 100% oxygen at high airway pressures enables the pilot's alveolar PO(2) to be maintained at a safe level during emergency descent. Introduced in military aviation, pressure breathing for G-tolerance and pressure breathing for altitude presented as concepts that may be of general physiological interest to many anesthesiologists.

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.

Science.gov (United States)

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.

Group-Level Coping as a Moderator between Heterosexism and Sexism and Psychological Distress in Sexual Minority Women

Science.gov (United States)

Szymanski, Dawn M.; Owens, Gina P.

2009-01-01

The purpose of this study was: (1) to examine concurrently the relationship between heterosexist events and sexist events and psychological distress and (2) to investigate sexual orientation-based and gender-based group-level coping as potential moderators of the heterosexism-distress and sexism-distress links among 282 lesbian and bisexual women.…

Understanding of Altitude Illness and Use of Pharmacotherapy Among Trekkers and Porters in the Annapurna Region of Nepal.

Science.gov (United States)

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.

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

Science.gov (United States)

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

2016-02-23

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

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.

Effect of Simulated Intermittent Altitude on the Metabolic and Hematologic Parameters in Streptozotocin Induced Diabetic Rats

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mehdi Faramoushi

2016-04-01

Full Text Available Background & objectives: Type II diabetes is a metabolic disorder accompanied with insulin resistance of the whole body cells and is considered be the fifth cause of death in the world. Adaptation to altitude can lead to tolerance to many diseases. Therefore, the aim of this study was to determine the effect of simulated intermittent altitude on the metabolic and hematologic parameters and liver function in streptozotocin induced diabetic rats. Methods: In the current experimental study, twenty four male Wistar rats weighing 220±20 gr were randomly divided into three groups; normal control group (NC, n=8, diabetic control group (D, n=8 received fat diet for 2 weeks then were injected with streptozotocin (37 mg/kg and diabetic+hypoxia group (D+H, n=8 including diabetic rat exposed to chronic intermittent hypoxia (PiO2≈106 mm Hg, simulated altitude≈3400 m, 14% oxygen for 8 weeks. Diabetic, hematologic and lipid parameters as well as ALT and AST activities were measured in peripheral blood. Results: Our findings showed that intermittent hypoxia significantly decreased serum total cholesterol, LDL ,VLDL and triglyceride in D+H group compared to D group (p<0.05. Serum levels of fasting blood glucose and homeostatic model assessment-insulin resistance HOMA-IR( index and ALT were decreased in D+H group vs. D group p<0.05. Also, hemoglubin and hematocrite level increased in D+H group in comparison to D group p<0.05. No significant difference was detected in red blood cell count in D+H vs. D group. Conclusion: Based on resultant data, it seems that intermittent exposure to hypoxia (simulated to chronic and intermittent lodgement in altitude can be used to control of type 2 diabetes by increasing hemoglobin, decreasing insulin resistance and improving liver function as well as lipid parameters.

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.

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

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Jiří Suchý

2015-03-01

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

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

Directory of Open Access Journals (Sweden)

Caroline Buss

2006-02-01

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

The Study of a Super Low Altitude Satellite

Science.gov (United States)

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.

Management of HAPE with bed rest and supplemental oxygen in hospital setting at high altitude (11,500 ft: A review of 43 cases

Directory of Open Access Journals (Sweden)

Sanjay Singhal

2017-01-01

Full Text Available Objectives: To evaluate the safety and efficacy of treating high-altitude pulmonary edema (HAPE by bed rest and supplemental oxygen in hospital setting at high altitude. Materials and Methods: In a prospective case series, all patients who were diagnosed clinically with HAPE on admission to our hospital located at a height of 11,500 ft were evaluated and managed with bed rest and oxygen supplementation. Results: A total of 43 patients of HAPE with mean age of 31 years (range 20–48 years were admitted to our hospital. Infections followed by unaccustomed physical exertion were the predominant risk factors. 95.35% of the patients improved successfully with oxygen and bed rest alone with mean hospital stay of 2.67 ± 1.06 (1–6 days. Two patients (4.65% required nifedipine and evacuation to lower altitude. Of this, one patient suffering from concomitant viral infection expired 4 days after evacuation to near sea level. Conclusion: Majority of the patients with HAPE where medical facilities are available can be safely treated with bed rest and oxygen supplementation at moderate high altitude without descent.

Optimization technique of the stay of person in the middle-altitude conditions

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Borisenko O.V.

2013-12-01

Full Text Available The objective: In order to improve exercise capacity in the middle-altitude conditions a technique of urgent adaptation with use of the compact device has been developed. Material and Methods. The study included two groups of people involved in mountain tourism, on the move and stay in the midlands, which used (experimental group and didn't use (control group the developed technique. Considering the specificity of observations directly on the mountain route, the compact equipment and functional studies (pulse oximetry, spirometry, peak flow, the dynamic measurement of pulse and blood pressure with the calculation of double product index were used to monitor the experiment. Results. During the experiment changes of the data characterizing positive development of the functioning of human cardiore-spiratory system during the physical activities in the conditions of middle mountains were recorded (peak expiratory flow rate (from 512,86 to 592,86 I / min, t = 2,25, or by 115,6% in the experimental group and double product index (from 95,66 to 127,09 units., t = 2,41, or by 132,9% in the experimental group. Conclusion. Thus, the offered device and its technique compose an effective scheme of preliminary preparation of cardiorespiratory system to stay in the middle-altitude condition and can be recommended for use in need short-term adaptation.

Normobaric Hypoxia Exposure during Low Altitude Stay and Performance of Elite-Level Race-Walkers

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Gaurav Sikri, AB Srinivasa

2016-06-01

Full Text Available We read with profound interest the article titled ‘Increased hypoxic dose after training at low altitude with 9h per night at 3000m normobaric hypoxia’ by Carr et al. (2015. Authors have concluded that low altitude (1380 m combined with normobaric hypoxia of 3000 m improves total haemoglobin mass (Hbmass and is an effective alternate method for training. Like other studies on elite athletes, the authors of present work have brought out that a major limitation was non-availability of a control group consisting of subjects undertaking same supervised training at normoxia. The total number of ‘possible’ subjects for control group which were taken from a previous study (Saunders et al., 2010 was 11 i.e placebo group (n = 6; 3 male and 3 female and Nocebo group (n = 5; 3 female and 2 male. It seems likely that authors of the present study have chosen only 10 subjects out of those 11. The criteria for exclusion of one subject and selection of 10 out of 11 subjects from the previous study to form the control group of the present study may require further elaboration.

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

Science.gov (United States)

Gonzales, Gustavo F

2011-03-01

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

The effects of altitude training on the AMPK-related glucose transport pathway in the red skeletal muscle of both lean and obese Zucker rats.

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Chen, Yu-Ching; Lee, Shin-Da; Kuo, Cha-Hua; Ho, Low-Tone

2011-01-01

The skeletal muscle AMP-activated protein kinase (AMPK)-related glucose transport pathway is involved in glucose homeostasis. In this study, we examined whether obese control Zucker rats had abnormal expression of proteins in the LKB1-AMPK-AS160-GLUT4 pathway in red gastrocnemius muscle compared to that in lean (normal) control Zucker rats. We also compared the chronic training effects of exercise, hypoxia, and altitude training on this pathway in lean and obese rats. At sea level, lean and obese rats were divided into 4 groups for 6 weeks training as follows: 1) control; 2) exercise (progressive daily swimming-exercise training with comparable exercise signals between the two groups); 3) hypoxia (8 hours of daily 14% O2 exposure); and 4) exercise plus hypoxia (also called altitude training). Seven animals were used for each group. The obese rats in the control group had higher body weights, elevated fasting insulin and glucose levels, and higher baseline levels of muscle AMPK and AS160 phosphorylation compared with those of lean control rats. For obese Zucker rats in the exercise or hypoxia groups, the muscle AMPK phosphorylation level was significantly decreased compared with that of the control group. For obese Zucker rats in the altitude training group, the levels of AMPK, AS160 phosphorylation, fasting insulin, and fasting glucose were decreased concomitant with an approximate 50% increase in the muscle GLUT4 protein level compared with those of the control group. In lean rats, the altitude training efficiently lowered fasting glucose and insulin levels and increased muscle AMPK and AS160 phosphorylation as well as GLUT4 protein levels. Our results provide evidence that long-term altitude training may be a potentially effective nonpharmacological strategy for treating and preventing insulin resistance based on its effects on the skeletal muscle AMPK-AS160-GLUT4 pathway.

Does 'altitude training' increase exercise performance in elite athletes?

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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.

Longitudinal Associations between Parenting and Youth Adjustment in Twelve Cultural Groups: Cultural Normativeness of Parenting as a Moderator

Science.gov (United States)

Lansford, Jennifer E.; Godwin, Jennifer; Al-Hassan, Suha M.; Bacchini, Dario; Bornstein, Marc H.; Chang, Lei; Chen, Bin-Bin; Deater-Deckard, Kirby; Di Giunta, Laura; Dodge, Kenneth A.; Malone, Patrick S.; Oburu, Paul; Pastorelli, Concetta; Skinner, Ann T.; Sorbring, Emma; Steinberg, Laurence; Tapanya, Sombat; Alampay, Liane Peña; Uribe Tirado, Liliana Maria; Zelli, Arnaldo

2018-01-01

To examine whether the cultural normativeness of parents' beliefs and behaviors moderates the links between those beliefs and behaviors and youths' adjustment, mothers, fathers, and children (N = 1,298 families) from 12 cultural groups in 9 countries (China, Colombia, Italy, Jordan, Kenya, Philippines, Sweden, Thailand, and the United States) were…

Effects of high-altitude environment on cognitive function and ultrastructure in CA1 region of hippocampus of rats after sleep deprivation

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Jiang-hua SI

2014-04-01

Full Text Available Objective To investigate the effects of high-altitude environment on cognitive function and ultrastructure in CA1 region of the hippocampus of Wistar rats in sleep deprivation (SD.  Methods SD was induced in Wistar rats by employing "flower pot" technique. Sixty-four rats were randomly divided into 2 groups: Lanzhou group (at an altitude of 1520 m and Kekexili group (at an altitude of 4767 m, and each group was further divided into 4 subgroups according to the time of SD (0, 1, 3 and 5 d. The behaviors of rats were studied by Morris water maze test at given time points. The ultrastructure of hippocampal neurons was observed by transmission electron microscope (TEM.  Results 1 Compared with Lanzhou group, rat behavior of Kekexili group presented excitement-irritation-suppression changes with the extension of SD time, but the extent was weakened gradually, and time of sleepiness increased obviously. 2 Compared with Lanzhou group, neurons in CA1 region of hippocampus showed enlarged cell body, disappeared nuclear membrane, shrunken nuclei and decreased organelle. End-feet of glia cells sticking to capillaries swelled and ruptured, and the typical synaptic structure disappeared. 3 Morris water maze test: as compared with Lanzhou group, the escape latency of Kekexili group prolonged (P < 0.05, for all, the ability of distance exploration increased (P < 0.05, for all, and the times across plot decreased (P < 0.05, for all in 1, 3 and 5 d of SD.  Conclusions High-altitude environment may significantly influence the cognitive function of rats in SD, and there was close correlation between the cognitive disorders and the changes in the ultrastructure of hippocampal CA1 region. doi: 10.3969/j.issn.1672-6731.2014.04.012

Altitude valve for railway suspension control system

Science.gov (United States)

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.

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

Science.gov (United States)

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.

Group boundary permeability moderates the effect of a dependency meta-stereotype on help-seeking behaviour.

Science.gov (United States)

Zhang, Lange; Kou, Yu; Zhao, Yunlong; Fu, Xinyuan

2016-08-01

Previous studies have found that when low-status group members are aware that their in-group is stereotyped as dependent by a specific out-group (i.e. a dependency meta-stereotype is salient), they are reluctant to seek help from the high-status out-group to avoid confirming the negative meta-stereotype. However, it is unclear whether low-status group members would seek more help in the context of a salient dependency meta-stereotype when there is low (vs. high) group boundary permeability. Therefore, we conducted two experiments to examine the moderating effect of permeability on meta-stereotype confirmation with a real group. In study 1, we manipulated the salience of the dependency meta-stereotype, measured participants' perceived permeability and examined their help-seeking behaviour in a real-world task. Participants who perceived low permeability sought more help when the meta-stereotype was salient (vs. not salient), whereas participants who perceived high permeability sought the same amount of help across conditions. In study 2, we manipulated the permeability levels and measured the dependency meta-stereotype. Participants who endorsed a high-dependency meta-stereotype sought more help than participants who endorsed a low-dependency meta-stereotype; this effect was particularly strong in the low-permeability condition. The implications of these results for social mobility and intergroup helping are discussed. © 2015 International Union of Psychological Science.

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

Science.gov (United States)

Brutsaert, Tom

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

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

Science.gov (United States)

Ader, Marilyn; Bergman, Richard N.

2015-01-01

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

CAMEX-4 ER-2 HIGH ALTITUDE DROPSONDE V1

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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...

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)

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

Perceived Ethnic Discrimination and Problem Behaviors in Muslim Immigrant Early Adolescents : Moderating Effects of Ethnic, Religious, and National Group Identification

NARCIS (Netherlands)

Maes, Marlies; Stevens, Gonneke W. J. M.; Verkuijten, Maykel

2014-01-01

Previous research has identified ethnic group identification as a moderator in the relationship between perceived ethnic discrimination and problem behaviors in ethnic minority children. However, little is known about the influence of religious and host national identification on this relationship.

Influence of growing altitude, shade and harvest period on quality and biochemical composition of Ethiopian specialty coffee.

Science.gov (United States)

Tolessa, Kassaye; D'heer, Jolien; Duchateau, Luc; Boeckx, Pascal

2017-07-01

Coffee quality is a key characteristic for the international market, comprising cup quality and chemical bean constituents. In Ethiopia, using total specialty cup scores, coffees are grouped into Q1 (specialty 1) ≥ 85 and Q2 (80-84.75). This classification results in market segmentation and higher prices. Although different studies have evaluated the effects of altitude and shade on bean quality, optimum shade levels along different altitudinal ranges are not clearly indicated. Information on effects of harvest periods on coffee quality is also scanty. The present study examined the influences of these factors and their interactions on Ethiopian coffee quality RESULTS: Coffee from high altitude with open or medium shade and early to middle harvest periods had a superior bean quality. These growing conditions also favoured the production of beans with lower caffeine. An increasing altitude, from mid to high, at approximately 400 m, decreased caffeine content by 10%. At high altitude, dense shade decreased Q1 coffee by 50%. Compared to late harvesting, early harvesting increased the percentage from 27% to 73%. At mid altitude, > 80% is Q2 coffee. Changes of quality scores driven by altitude, shade and harvest period are small, although they may induce dramatic switches in the fraction Q1 versus Q2 coffee. The latter affects both farmers' profits and competitiveness in international markets. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Plants, birds and butterflies: short-term responses of species communities to climate warming vary by taxon and with altitude.

Science.gov (United States)

Roth, Tobias; Plattner, Matthias; Amrhein, Valentin

2014-01-01

As a consequence of climate warming, species usually shift their distribution towards higher latitudes or altitudes. Yet, it is unclear how different taxonomic groups may respond to climate warming over larger altitudinal ranges. Here, we used data from the national biodiversity monitoring program of Switzerland, collected over an altitudinal range of 2500 m. Within the short period of eight years (2003-2010), we found significant shifts in communities of vascular plants, butterflies and birds. At low altitudes, communities of all species groups changed towards warm-dwelling species, corresponding to an average uphill shift of 8 m, 38 m and 42 m in plant, butterfly and bird communities, respectively. However, rates of community changes decreased with altitude in plants and butterflies, while bird communities changed towards warm-dwelling species at all altitudes. We found no decrease in community variation with respect to temperature niches of species, suggesting that climate warming has not led to more homogenous communities. The different community changes depending on altitude could not be explained by different changes of air temperatures, since during the 16 years between 1995 and 2010, summer temperatures in Switzerland rose by about 0.07°C per year at all altitudes. We discuss that land-use changes or increased disturbances may have prevented alpine plant and butterfly communities from changing towards warm-dwelling species. However, the findings are also consistent with the hypothesis that unlike birds, many alpine plant species in a warming climate could find suitable habitats within just a few metres, due to the highly varied surface of alpine landscapes. Our results may thus support the idea that for plants and butterflies and on a short temporal scale, alpine landscapes are safer places than lowlands in a warming world.

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...

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)

Cortisol awakening response and emotion at extreme altitudes on Mount Kangchenjunga.

Science.gov (United States)

Aguilar, Raúl; Martínez, Carlos; Alvero-Cruz, José R

2017-12-24

The cortisol awakening response (CAR) was examined over a 45days stay at extreme altitudes (above of about 5500m) on Mount Kangchenjunga. The CAR refers to a peak cortisol response during the waking period that is superimposed to the diurnal rhythmicity in cortisol secretion, whose function has been proposed to be the anticipation of demands of the upcoming day (the CAR anticipation hypothesis). According to this hypothesis, we distinguished between resting days on which the expedition team engaged in routine activities in the base camp, and ascent days on which it planned to climb up a very demanding track. We were also interested in examining the association of testosterone with emotional anticipation, given the role of this steroid hormone in reward-related processes in challenge situations. Results showed that the climber group had a bigger CAR on ascent days, relative to the Sherpa group at the same altitude and the non-climber group at sea level. Several methodological issues, however, made it difficult to interpret these group differences in terms of the CAR anticipation hypothesis (e.g. a seemingly influential covariate was awakening time). Although based on tentative results, correlational and regression analyses controlling for awakening time coherently showed that the CAR was associated with anticipation of a hard day and feelings of fear, and testosterone was associated with feelings of energy and positive affect. Whether or not the anticipation of a hard day played a key role in regulation of the CAR, the observation of an intact CAR in the climber group under hypobaric hypoxia conditions would require in-depth reflection from the perspective of human adaptive evolution. Copyright © 2017 Elsevier B.V. All rights reserved.

High altitude pulmonary edema among "Amarnath Yatris"

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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.

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...

High altitude organic gold

DEFF Research Database (Denmark)

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

2018-01-01

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

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

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Ming-sen ZHANG

2011-01-01

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

Exploring the Limits of High Altitude GPS for Future Lunar Missions

Science.gov (United States)

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

2018-01-01

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

Mobile platform of altitude measurement based on a smartphone

Science.gov (United States)

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.

Electrolyte-carbohydrate beverage prevents water loss in the early stage of high altitude training.

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Yanagisawa, Kae; Ito, Osamu; Nagai, Satsuki; Onishi, Shohei

2012-01-01

To prevent water loss in the early stage of high altitude training, we focused on the effect of electrolyte-carbohydrate beverage (EC). Subjects were 16 male university students who belonged to a ski club. They had ski training at an altitude of 1,800 m. The water (WT) group drank only water, and the EC group drank only an electrolyte-carbohydrate beverage. They arrived at the training site in the late afternoon. The study started at 7 pm on the day of arrival and continued until noon of the 4(th) day. In the first 12 hours, 1 L of beverages were given. On the second and third days, 2.5 L of beverages were given. All subjects ate the same meals. Each morning while in fasting condition, subjects were weighed and blood was withdrawn for various parameters (hemoglobin, hematocrit, sodium, potassium and aldosterone). Urine was collected at 12 hour intervals for a total 60 hours (5 times). The urine volume, gravity, sodium and potassium concentrations were measured. Peripheral oxygen saturation and heart rate were measured during sleep with a pulse oximeter. Liquid intakes in both groups were similar, hence the electrolytes intake was higher in the EC group than in the WT group. The total urine volume was lower in the EC group than in the WT group, respectively (paltitude training may be effective in decreasing urinary output and preventing loss of blood plasma volume.

Effect of altitude on physiological performance: a statistical analysis using results of international football games.

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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

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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

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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

OpenAIRE

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

2011-01-01

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

Prevalence of photodermatosis in four regions at different altitudes in Yunnan province, China.

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Deng, Danqi; Hang, Yuntao; Chen, Hao; Li, Hanying

2006-08-01

Idiopathic photodermatoses are common diseases in dermatology clinics that are associated with ultraviolet (UV) irradiation. The group includes a few dermatoses such as polymorphous light eruption (PLE) and chronic actinic dermatitis (CAD). The prevalence of PLE and CAD in China has not been previously reported. To investigate the population-based prevalence of polymorphous light eruption (PLE) and chronic actinic dermatitis (CAD) in six minority groups living in four regions with significantly different altitudes in the Yunnan province, a questionnaire survey was administered to 4899 residents of random villages in Yuanjiang county (Dai and Hani minorities), Kunming city (Han people and Yi minority), Lijiang county (Naxi minority), and Shangri-La county (Zang minority). The altitudes of these counties are 380 m, 1870 m, 2410 m and 3280 m a.s.l., respectively. The results showed that, first, there were 2400 males (49.0%) and 2499 females (51.0%). The prevalence of PLE was 0.65% (32/4899), and the prevalence of CAD was 0.18% (9/4899). PLE was higher among females than males (3.8 vs 1, P 0.05). Second, the prevalence of PLE was increased in higher elevations regions compared to lower elevations (P 0.05). Third, the mean times of sun exposure for PLE and CAD were 6.0 and 6.5 h/day, respectively. The mean durations of PLE and CAD were 5.8 years, and 6.6 years, respectively. The study demonstrated that the prevalence of PLE is higher than that of CAD in Yunnan, and that the prevalence of PLE is correlated with altitude.

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

Accuracy of Handheld Blood Glucose Meters at High Altitude

NARCIS (Netherlands)

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

2010-01-01

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

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

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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.

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

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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

Inverse association between altitude and obesity: A prevalence study among Andean and low-altitude adult individuals of Peru

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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

Inverse association between altitude and obesity: A prevalence study among andean and low-altitude adult individuals of Peru.

Science.gov (United States)

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?

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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.

Local adaptation to altitude underlies divergent thermal physiology in tropical killifishes of the genus Aphyosemion.

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David J McKenzie

Full Text Available In watersheds of equatorial West Africa, monophyletic groups of killifish species (genus Aphyosemion occur in discrete altitudinal ranges, low altitude species (LA, sea level to ∼350 m or high altitude species (HA, 350 to 900 m. We investigated the hypothesis that local adaptation to altitude by the LA and HA species would be revealed as divergent effects of temperature on their physiological energetics. Two species from each group (mass ∼350 mg were acclimated to 19, 25 and 28°C, with 19 and 28°C estimated to be outside the thermal envelope for LA or HA, respectively, in the wild. Wild-caught animals (F0 generation were compared with animals raised in captivity at 25°C (F1 generation to investigate the contribution of adaptation versus plasticity. Temperature significantly increased routine metabolic rate in all groups and generations. However, LA and HA species differed in the effects of temperature on their ability to process a meal. At 25°C, the specific dynamic action (SDA response was completed within 8 h in all groups, but acclimation to temperatures beyond the thermal envelope caused profound declines in SDA performance. At 19°C, the LA required ∼14 h to complete the SDA, whereas the HA required only ∼7 h. The opposite effect was observed at 28°C. This effect was evident in both F0 and F1. Reaction norms for effects of temperature on SDA therefore revealed a trade-off, with superior performance at warmer temperatures by LA being associated with inferior performance at cooler temperatures, and vice-versa in HA. The data indicate that divergent physiological responses to temperature in the LA and HA species reflect local adaptation to the thermal regime in their habitat, and that local adaptation to one thermal environment trades off against performance in another.

The risk of cardiovascular events during leisure time activities at altitude.

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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.

The FAA altitude chamber training flight profile : a survey of altitude reactions, 1965-1989.

Science.gov (United States)

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

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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.

Adaptation to Altitude as a Vehicle for Experiential Learning of Physiology by University Undergraduates

Science.gov (United States)

Weigle, David S.; Buben, Amelia; Burke, Caitlin C.; Carroll, Nels D.; Cook, Brett M.; Davis, Benjamin S.; Dubowitz, Gerald; Fisher, Rian E.; Freeman, Timothy C.; Gibbons, Stephen M.; Hansen, Hale A.; Heys, Kimberly A.; Hopkins, Brittany; Jordan, Brittany L.; McElwain, Katherine L.; Powell, Frank L.; Reinhart, Katherine E.; Robbins, Charles D.; Summers, Cameron C.; Walker, Jennifer D.; Weber, Steven S.; Weinheimer, Caroline J.

2007-01-01

In this article, an experiential learning activity is described in which 19 university undergraduates made experimental observations on each other to explore physiological adaptations to high altitude. Following 2 wk of didactic sessions and baseline data collection at sea level, the group ascended to a research station at 12,500-ft elevation.…

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

Science.gov (United States)

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

2010-12-15

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

Energy efficiency and comfort conditions in passive solar buildings: Effect of thermal mass at equatorial high altitudes

Science.gov (United States)

Ogoli, David Mwale

This dissertation is based on the philosophy that architectural design should not just be a function of aesthetics, but also of energy-efficiency, advanced technologies and passive solar strategies. A lot of published literature is silent regarding buildings in equatorial highland regions. This dissertation is part of the body of knowledge that attempts to provide a study of energy in buildings using thermal mass. The objectives were to establish (1) effect of equatorial high-altitude climate on thermal mass, (2) effect of thermal mass on moderating indoor temperatures, (3) effect of thermal mass in reducing heating and cooling energy, and (4) the amount of time lag and decrement factor of thermal mass. Evidence to analyze the effect of thermal mass issues came from three sources. First, experimental physical models involving four houses were parametrically conducted in Nairobi, Kenya. Second, energy computations were made using variations in thermal mass for determining annual energy usage and costs. Third, the data gathered were observed, evaluated, and compared with currently published research. The findings showed that: (1) Equatorial high-altitude climates that have diurnal temperature ranging about 10--15°C allow thermal mass to moderate indoor temperatures; (2) Several equations were established that indicate that indoor mean radiant temperatures can be predicted from outdoor temperatures; (3) Thermal mass can reduce annual energy for heating and cooling by about 71%; (4) Time lag and decrement of 200mm thick stone and concrete thermal mass can be predicted by a new formula; (5) All windows on a building should be shaded. East and west windows when shaded save 51% of the cooling energy. North and south windows when fully shaded account for a further 26% of the cooling energy; (6) Insulation on the outside of a wall reduces energy use by about 19.6% below the levels with insulation on the inside. The basic premise of this dissertation is that decisions that

Only minor additional metabolic health benefits of high as opposed to moderate dose physical exercise in young, moderately overweight men.

Science.gov (United States)

Reichkendler, M H; Rosenkilde, M; Auerbach, P L; Agerschou, J; Nielsen, M B; Kjaer, A; Hoejgaard, L; Sjödin, A; Ploug, T; Stallknecht, B

2014-05-01

The dose-response effects of exercise training on insulin sensitivity, metabolic risk, and quality of life were examined. Sixty-one healthy, sedentary (VO₂max: 35 ± 5 ml/kg/min), moderately overweight (BMI: 27.9 ± 1.8), young (age: 29 ± 6 years) men were randomized to sedentary living (sedentary control group; n = 18), moderate (moderate dose training group [MOD]: 300 kcal/day, n = 21), or high (high dose training group [HIGH]: 600 kcal/day, n = 22) dose physical exercise for 11 weeks. The return rate for post-intervention testing was 82-94% across groups. Weekly exercise amounted to 2,004 ± 24 and 3,774 ± 68 kcal, respectively, in MOD and HIGH. Cardiorespiratory fitness increased (P exercise groups (MOD: 32 ± 1 to 29 ± 1%; HIGH: 30 ± 1 to 27 ± 1%). Peripheral insulin sensitivity increased (P benefits were found when exercising ∼3,800 as opposed to ∼2,000 kcal/week in young moderately overweight men. This finding may have important public health implications. Copyright © 2012 The Obesity Society.

Fit for high altitude: are hypoxic challenge tests useful?

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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?

Science.gov (United States)

Matthys, Heinrich

2011-02-28

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

A comparison of the incidence and understanding of altitude illness between porters and trekkers in the Solu Khumbu Region of Nepal.

Science.gov (United States)

Newcomb, Lauren; Sherpa, Chhewang; Nickol, Annabel; Windsor, Jeremy

2011-09-01

Altitude illness can occur in anyone who ascends to high altitude. Better understanding of altitude illness is associated with a lower incidence of acute mountain sickness (AMS). The purpose of this study is to compare, for the first time, the incidence and understanding of altitude illness between foreign trekkers and indigenous porters in Nepal. Interviews and questionnaires were completed at the International Porter Protection Group Rescue Post at Machermo (4470 m). Participants completed the Lake Louise acute mountain sickness self-assessment questionnaire. They were also asked about their actions in response to high altitude illness scenarios as well as their perception of the vulnerability of porters vs trekkers to altitude illness. Ascent profile, age, gender, ethnic origin, and altitude of home residence were also obtained. Trekkers (n=131) had a significantly higher incidence of AMS (21% vs 8%) than porters (n=92; P porters (whose home villages were below 3050 m, n=61) had a numerically higher, though not significantly different, incidence of AMS (10% vs 3%) compared to highland porters (n=31). The majority of trekkers and porters recognized the symptoms of altitude illness and the most appropriate action to be taken. Despite the lower incidence of AMS in porters, around half felt that they were at greater risk than trekkers. Porters had a lower incidence of AMS, which may be attributable to repeated ascents through the trekking season, or differences in reporting symptoms. Both trekkers and porters demonstrated appropriate knowledge of actions to be taken in response to altitude illness. Copyright © 2011 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

Moderator Chemistry Program

International Nuclear Information System (INIS)

Dewitt, L.V.; Gibbs, A.; Lambert, D.P.; Bohrer, S.R.; Fanning, R.L.; Houston, M.W.; Stinson, S.L.; Deible, R.W.; Abdel-Khalik, S.I.

1990-11-01

Over the past fifteen months, the Systems Chemistry Group of the Reactor Engineering Department has undertaken a comprehensive study of the Department's moderator chemistry program at Savannah River Site (SRS). An internal review was developed to formalize and document this program. Objectives were as outlined in a mission statement and action plan. In addition to the mission statement and action plan, nine separate task reports have been issued during the course of this study. Each of these task reports is included in this document as a chapter. This document is an organized compilation of the individual reports issued by the Systems Chemistry Group in assessment of SRS moderator chemistry to determine if there were significant gaps in the program as ft existed in October, 1989. While these reviews found no significant gaps in that mode of operation, or any items that adversely affected safety, items were identified that could be improved. Many of the items have already been dear with or are in the process of completion under this Moderator Chemistry Program and other Reactor Restart programs. A complete list of the items of improvement found under this assessment is found in Chapter 9, along with a proposed time table for correcting remaining items that can be improved for the chemistry program of SRS reactors. An additional external review of the moderator chemistry processes, recommendations, and responses to/from the Reactor Corrosion Mitigation Committee is included as Appendix to this compilation

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

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

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

Science.gov (United States)

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

2017-01-01

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

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

Science.gov (United States)

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

2015-01-01

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

Shape memory alloy resistance behaviour at high altitude for feedback control

Science.gov (United States)

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

2017-12-01

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

Ocular morbidity among porters at high altitudes.

Science.gov (United States)

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

2017-01-01

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

Perseus A High Altitude Remotely Piloted Aircraft being Towed in Flight

Science.gov (United States)

1994-01-01

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

EFECTO DEL ASCENSO SÚBITO A UNA ALTITUD MODERADA SOBRE LA PERCEPCIÓN SUBJETIVA DE ESFUERZO A DIFERENTES INTENSIDADES DE EJERCICIO

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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

Moderate Secularism and Multicultural Equality

DEFF Research Database (Denmark)

Lægaard, Sune

2008-01-01

Tariq Modood argues that European states are only ‘moderately secular' and that this kind of secularism is compatible with public accommodation of religious groups and provides a model of Muslim integration appropriate for European states. Although attention to the fact of moderate secularism...... provides a response to a prominent argument against multicultural accommodation of religious minorities, what is really at stake in discussions of multiculturalism and secularism are political principles. Modood's case for accommodation of Muslims along the lines of moderate secularism presupposes...

Altitude training: an up-to-date approach and implementation in practice

OpenAIRE

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 ...

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

Science.gov (United States)

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

2017-12-05

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

Increases in .VO2max with "live high-train low" altitude training: role of ventilatory acclimatization.

Science.gov (United States)

Wilhite, Daniel P; Mickleborough, Timothy D; Laymon, Abigail S; Chapman, Robert F

2013-02-01

The purpose of this study was to estimate the percentage of the increase in whole body maximal oxygen consumption (.VO(2max)) that is accounted for by increased respiratory muscle oxygen uptake after altitude training. Six elite male distance runners (.VO(2max) = 70.6 ± 4.5 ml kg(-1) min(-1)) and one elite female distance runner (.VO(2max)) = 64.7 ml kg(-1) min(-1)) completed a 28-day "live high-train low" training intervention (living elevation, 2,150 m). Before and after altitude training, subjects ran at three submaximal speeds, and during a separate session, performed a graded exercise test to exhaustion. A regression equation derived from published data was used to estimate respiratory muscle .VO(2) (.VO(2RM)) using our ventilation (.VE) values. .VO(2RM) was also estimated retrospectively from a larger group of distance runners (n = 22). .VO(2max) significantly (p altitude (196 ± 59 ml min(-1)), while (.VE) at .VO(2max) also significantly (p altitude (201 ± 36 ml min(-1)), along with a 10.8 ± 2.1 l min(-1) increase in (.VE), thus requiring an estimated 27 % of Δ .VO(2max) Our data suggest that a substantial portion of the improvement in .VO(2max) with chronic altitude training goes to fuel the respiratory muscles as opposed to the musculature which directly contributes to locomotion. Consequently, the time-course of decay in ventilatory acclimatization following return to sea-level may have an impact on competitive performance.

Beta-fibrinogen allele frequencies in Peruvian Quechua, a high-altitude native population.

Science.gov (United States)

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

1999-06-01

Elevated hematocrits, which are found in many high-altitude populations, increase the oxygen-carrying capacity of blood and may represent an adaptation to hypoxic environments. However, as high hematocrit increases blood viscosity, which in turn is associated with hypertension and heart disease, it may be advantageous for high-altitude populations to limit other factors that contribute to increased blood viscosity. One such factor is the plasma concentration of the coagulation protein fibrinogen. Several common polymorphisms in the beta-fibrinogen gene have been identified that affect fibrinogen concentrations. We determined the allele frequencies of three of these polymorphisms (G/A-455(HaeIII), C/T-148(HindIII), and G/A+448(MnlI)) in sample groups drawn from three populations: Quechua-speaking natives living at over 3,200 m in the Peruvian Andes, North American natives (Na-Dene) from coastal British Columbia, and Caucasian North Americans. The frequencies of the alleles previously shown to be associated with increased fibrinogen levels were so low in the Quechuas that their presence could be accounted for solely by genetic admixture with Caucasians. Frequencies in the Na-Dene, a Native American group unrelated to the Quechua, were not significantly different from those in Caucasians.

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

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G K Singh

2013-01-01

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

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

Science.gov (United States)

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

2016-06-01

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

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

International Nuclear Information System (INIS)

Sun Jingwen

1999-11-01

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

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

Is BMR repeatable in deer mice? Organ mass correlates and the effects of cold acclimation and natal altitude.

Science.gov (United States)

Russell, G A; Chappell, M A

2007-01-01

Basal metabolic rate (BMR) is probably the most studied aspect of energy metabolism in vertebrate endotherms. Numerous papers have explored its mass allometry, phylogenetic and ecological relationships, and ontogeny. Implicit in many of these studies (and explicit in some) is the view that BMR responds to selection, which requires repeatability and heritability. However, BMR is highly plastic in response to numerous behavioral and environmental factors and there are surprisingly few data on its repeatability. Moreover, the mechanistic underpinnings of variation in BMR are unclear, despite considerable research. We studied BMR repeatability in deer mice (Peromyscus maniculatus) across intervals of 30-60 days, and also examined the influence of birth altitude (3,800 m versus 340 m) and temperature acclimation (to approximately 5 or approximately 20 degrees C) on BMR, and the relationship between BMR and organ size. Neither acclimation temperature nor natal altitude alone influenced BMR, but the combination of birth at high altitude and cold acclimation significantly increased BMR. Few visceral organ masses were correlated to BMR and most were inconsistent across natal altitudes and acclimation temperatures, indicating that no single organ 'controls' variation in BMR. In several treatment groups, the mass of the 'running motor' (combined musculoskeletal mass) was negatively correlated to BMR and the summed mass of visceral organs was positively correlated to BMR. We found no repeatability of BMR in any treatment group. That finding-in sharp contrast to high repeatability of BMR in several other small endotherms-suggests little potential for direct selection to drive BMR evolution in deer mice.

Radioisotope studies of steroid hormone levels of plasma in indigenous subjects living at high altitude and submitted to a low calorie diet

International Nuclear Information System (INIS)

Ramirez, I.

1975-08-01

Radioimmunological techniques were applied to the evaluation of TSH and ACTH in the four groups of Ecuadorian subjects under investigation at Tocachi, Malchingui, Quito and Portoviejo, the first three populations living at a high altitude and the fourth at sea-level. This evaluation was of interest since previous studies had indicated that there were thyroid and adrenal hormone deficiency levels in individuals from Tocachi and Malchingui or, in other words, in populations from a high-altitude region, and also endemic goitre and caloric-protein malnutrition. Furthermore, the Tocachi group was composed of subjects suffering from chronic ''stress''. Parallel to the analysis of TSH and pituitary ACTH levels, the circadian rhythm in the production of these hormones in these subjects was studied. The basal values of TSH and ACHT for the studied groups were found to lie within the normal range. 131 I-TSH and 125 I-ACTH were used. As far as the nycthemeral TSH rhythm is concerned, the values tended to be lowest for the high-altitude populations, while for the groups living at sea-level, where there is also circadian variation, the higher values are found in the morning. Similarly, the circadian rhythm for ACTH was established, with a predominance of diurnal values at Tocachi, Malchingui and Portoviejo

Three plasma metabolite signatures for diagnosing high altitude pulmonary edema

Science.gov (United States)

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

2015-10-01

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

Monocular Vision System for Fixed Altitude Flight of Unmanned Aerial Vehicles

Directory of Open Access Journals (Sweden)

Kuo-Lung Huang

2015-07-01

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

The effects of classic altitude training on hemoglobin mass in swimmers.

Science.gov (United States)

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.

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

Science.gov (United States)

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

2012-03-01

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

Transcriptome and network changes in climbers at extreme altitudes.

Directory of Open Access Journals (Sweden)

Fang Chen

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

Cerebral venous system and anatomical predisposition to high-altitude headache

NARCIS (Netherlands)

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

2013-01-01

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

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

Science.gov (United States)

Weinbruch, Stephan; Nordby, Karl-Christian

2013-12-01

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

[Geographic Altitude of Residence and Alcohol Dependence in a Peruvian Population].

Science.gov (United States)

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.

Surname-inferred Andean ancestry is associated with child stature and limb lengths at high altitude in Peru, but not at sea level.

Science.gov (United States)

Pomeroy, Emma; Wells, Jonathan C K; Stanojevic, Sanja; Miranda, J Jaime; Moore, Lorna G; Cole, Tim J; Stock, Jay T

2015-01-01

Native Andean ancestry gives partial protection from reduced birthweight at high altitude in the Andes compared with European ancestry. Whether Andean ancestry is also associated with body proportions and greater postnatal body size at altitude is unknown. Therefore, we tested whether a greater proportion of Andean ancestry is associated with stature and body proportions among Peruvian children at high and low altitude. Height, head circumference, head-trunk height, upper and lower limb lengths, and tibia, ulna, hand and foot lengths, were measured in 133 highland and 169 lowland children aged 6 months to 8.5 years. For highland and lowland groups separately, age-sex-adjusted anthropometry z scores were regressed on the number of indigenous parental surnames as a proxy for Andean ancestry, adjusting for potential confounders (maternal age and education, parity, altitude [highlands only]). Among highland children, greater Andean ancestry was negatively associated with stature and tibia, ulna, and lower limb lengths, independent of negative associations with greater altitude for these measurements. Relationships were strongest for tibia length: each additional Andean surname or 1,000 m increase at altitude among highland children was associated with 0.18 and 0.65 z score decreases in tibia length, respectively. Anthropometry was not significantly associated with ancestry among lowland children. Greater Andean ancestry is associated with shorter stature and limb measurements at high but not low altitude. Gene-environment interactions between high altitude and Andean ancestry may exacerbate the trade-off between chest dimensions and stature that was proposed previously, though we could not test this directly. © 2015 Wiley Periodicals, Inc.

Adding heat to the live-high train-low altitude model: a practical insight from professional football

Science.gov (United States)

Buchheit, M; Racinais, S; Bilsborough, J; Hocking, J; Mendez-Villanueva, A; Bourdon, P C; Voss, S; Livingston, S; Christian, R; Périard, J; Cordy, J; Coutts, A J

2013-01-01

Objectives To examine with a parallel group study design the performance and physiological responses to a 14-day off-season ‘live high-train low in the heat’ training camp in elite football players. Methods Seventeen professional Australian Rules Football players participated in outdoor football-specific skills (32±1°C, 11.5 h) and indoor strength (23±1°C, 9.3 h) sessions and slept (12 nights) and cycled indoors (4.3 h) in either normal air (NORM, n=8) or normobaric hypoxia (14±1 h/day, FiO2 15.2–14.3%, corresponding to a simulated altitude of 2500–3000 m, hypoxic (HYP), n=9). They completed the Yo-Yo Intermittent Recovery level 2 (Yo-YoIR2) in temperate conditions (23±1°C, normal air) precamp (Pre) and postcamp (Post). Plasma volume (PV) and haemoglobin mass (Hbmass) were measured at similar times and 4 weeks postcamp (4WPost). Sweat sodium concentration ((Na+)sweat) was measured Pre and Post during a heat-response test (44°C). Results Both groups showed very large improvements in Yo-YoIR2 at Post (+44%; 90% CL 38, 50), with no between-group differences in the changes (−1%; −9, 9). Postcamp, large changes in PV (+5.6%; −1.8, 5.6) and (Na+)sweat (−29%; −37, −19) were observed in both groups, while Hbmass only moderately increased in HYP (+2.6%; 0.5, 4.5). At 4WPost, there was a likely slightly greater increase in Hbmass (+4.6%; 0.0, 9.3) and PV (+6%; −5, 18, unclear) in HYP than in NORM. Conclusions The combination of heat and hypoxic exposure during sleep/training might offer a promising ‘conditioning cocktail’ in team sports. PMID:24282209

Cold induced peripheral vasodilation at high altitudes- a field study

NARCIS (Netherlands)

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

2000-01-01

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

Altitude Performance Characteristics of Tail-pipe Burner with Variable-area Exhaust Nozzle

Science.gov (United States)

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.

HSD is a better resuscitation fluid for hemorrhagic shock with pulmonary edema at high altitude.

Science.gov (United States)

Liu, Liang-Ming; Hu, De-Yao; Zhou, Xue-Wu; Liu, Jiang-Cang; Li, Ping

2008-12-01

To investigate the fluid tolerance of hemorrhagic shock with pulmonary edema (HSPE) at high altitude in unacclimated rats and the beneficial effect of 7.5% hypertonic saline/6% dextran (HSD). One hundred seventy-six Sprague-Dawley rats, transported to LaSa, Tibet, 3,760 m above the sea level, were anesthetized with sodium pentobarbital (30 mg/kg, i.p.) within 1 week. Hemorrhagic shock with pulmonary edema was induced by bloodletting (50 mmHg for 1 h) plus intravenous injection of oleic acid (50 microL/kg). Seventy-seven rats were equally divided into 11 groups (n = 7/group) including sham-operated control group; hemorrhagic shock control group; HSPE control group; HSPE plus 0.5-, 1.0-, 1.5-, 2.0-, or 3.0-fold volumes of lactated Ringer's solution (LR) groups; and HSPE plus 4, 6, and 8 mL/kg of HSD groups. Hemodynamic parameters including mean arterial blood pressure, left intraventricular systolic pressure, and the maximal change rate of intraventricular pressure rise or decline (+/-dp/dtmax) were observed at baseline and at 15, 30, 60, and 120 min after infusion; blood gases were measured at 30 and 120 min after infusion, and the water content of lung and brain was determined at 120 min after infusion. Additional 99 rats were used to observe the effect of these treatments on the survival time of HSPE rats; 0.5 volume of LR infusion slightly increased the mean arterial blood pressure, left intraventricular systolic pressure, and +/-dp/dtmax and prolonged the survival time of HSPE animals as compared with the HSPE group (P solution infusion, 1.5, 2, and 3 volumes, significantly deteriorated the hemodynamic parameters, increased the water content of lung, and decreased the survival time of HSPE animals. Hypertonic saline/6% dextran (4 - 8 mL/kg) significantly increased the hemodynamic parameters, improved the blood gases, decreased the water content of lung and brain, and prolonged the survival time of HSPE rats. Among the three dosages of HSD, 6 mL/kg of HSD had the

Erythropoietin, 2,3 DPG, oxygen transport capacity, and altitude training in adolescent Alpine skiers.

Science.gov (United States)

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

NARCIS (Netherlands)

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

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

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...

From Drinking Group Norms to Individual Drinking Consequences: A Moderated Mediation Model Examining the Role of Members' Status, Identification with the Group and with Emerging Adulthood.

Science.gov (United States)

Dumas, Tara M; Davis, Jordan P; Maxwell-Smith, Matthew A; Bell, Angelica

2018-07-03

Emerging adults consume alcohol most often with their peer drinking groups. Yet, little is known about the role of drinking group norms on individual members' drinking consequences, nor about the mechanisms that underlie this association. We examined the indirect relationship between drinking group descriptive norms (perceived frequency of group heavy episodic drinking; HED) and individual drinking consequences via individual HED. We also examined key moderators, including the extent to which individuals occupied high status positions within their drinking groups, the strength of their identification with the group, and the degree to which they identified with emerging adulthood, a developmental period associated with heightened alcohol consumption. Participants were 280 and 340 (replication study) emerging adults (18-29 years) who were recruited via an online crowdsourcing site to complete a survey. Across studies, higher status was associated with more individual HED and drinking consequences. Further, group identification and identification with emerging adulthood strengthened the relation between group and individual HED. Finally, the indirect relation between group HED and individual drinking consequences was significant and stronger for individuals who identified more with their drinking groups and with emerging adulthood. Conclusions/Importance: Findings contribute to a more nuanced understanding of the impact of descriptive peer norms on heavy drinking and related consequences in emerging adulthood and help identify drinking group members most at risk for internalizing descriptive group norms for HED. Key implications for prevention and intervention programming are discussed.

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

Science.gov (United States)

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

2017-07-08

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

Altitude training for elite endurance athletes: A review for the travel medicine practitioner.

Science.gov (United States)

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.

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

Science.gov (United States)

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

2015-12-01

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

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

Reduced oxygen at high altitude limits maximum size.

Science.gov (United States)

Peck, L S; Chapelle, G

2003-11-07

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

The Peer Group as a Context: Moderating Effects on Relations between Maternal Parenting and Social and School Adjustment in Chinese Children

Science.gov (United States)

Chen, Xinyin; Chang, Lei; He, Yunfeng; Liu, Hongyun

2005-01-01

This 2-year longitudinal study examined, in a sample of Chinese children (initial M age=11 years), the moderating effects of the peer group on relations between maternal supportive parenting and social and school adjustment. Data were collected from multiple sources including peer assessments, teacher ratings, school records, and maternal reports.…

Wilderness medicine at high altitude: recent developments in the field

Directory of Open Access Journals (Sweden)

Shah NM

2015-09-01

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

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.

Ixekizumab for Treating Moderate-to-Severe Plaque Psoriasis: An Evidence Review Group Perspective of a NICE Single Technology Appraisal.

Science.gov (United States)

Ramaekers, Bram L T; Wolff, Robert F; Pouwels, Xavier; Oosterhoff, Marije; Van Giessen, Anoukh; Worthy, Gill; Noake, Caro; Armstrong, Nigel; Kleijnen, Jos; Joore, Manuela A

2018-02-26

The National Institute for Health and Care Excellence invited Eli Lilly and Company Ltd, the company manufacturing ixekizumab (tradename Taltz ® ), to submit evidence for the clinical and cost effectiveness of ixekizumab. Ixekizumab was compared with tumour necrosis factor-α inhibitors (etanercept, infliximab, adalimumab), ustekinumab, secukinumab, best supportive care and, if non-biological treatment or phototherapy is suitable, also compared with systemic non-biological therapies and phototherapy with ultraviolet B radiation for adults with moderate-to-severe plaque psoriasis. Kleijnen Systematic Reviews Ltd, in collaboration with Maastricht University Medical Center, was commissioned as the independent Evidence Review Group. This article presents a summary of the company submission, the Evidence Review Group report and the development of the National Institute for Health and Care Excellence guidance for the use of this drug in England and Wales by the Appraisal Committee. The Evidence Review Group produced a critical review of the clinical and cost effectiveness of ixekizumab based on the company submission. The company submission presented three randomised controlled trials identified in a systematic review. All randomised controlled trials were phase III, multicentre placebo-controlled trials including 3866 participants with moderate-to-severe psoriasis. Two trials also included an active comparator (etanercept). All randomised controlled trials showed statistically significant increases in two primary outcomes, static Physician Global Assessment (0,1) and improvement of 75% from baseline in the Psoriasis Area and Severity Index. Ixekizumab was generally well tolerated in the randomised controlled trials, with similar discontinuation rates because of adverse events as placebo or etanercept. The most frequent adverse events of special interest were infections and injection-site reactions. The company submission also included a network meta-analysis of

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

Science.gov (United States)

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

2015-03-01

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

Effects of altitude and beehive bottom board type on wintering losses of honeybee colonies under subtropical climatic conditions

Energy Technology Data Exchange (ETDEWEB)

Ucak-Koc, A.

2014-06-01

The effects of altitude and beehive bottom board types (BBBT) on the wintering performance of honeybee colonies were investigated in the South Aegean Region of Turkey: Experiment I (E-I), with 32 colonies, in 2010-2011, and Experiment II (E-II), with 20 colonies, in 2011-2012. Each lowland (25 m) and highland (797 m) colony was divided randomly into two BBBT subgroups, open screen floor (OSF) and normal bottom floor (NBF), and wintered for about three months. In E-I, the local genotype Aegean ecotype of Anatolian bee (AE) and Italian race (ItR) were used, while in E-II, only the AE genotype was present. In E-I, the effect of wintering altitudes on the number of combs covered with bees (NCCB), and the effects of BBBT on brood area (BA) and the NCCB were found to be statistically significant (p < 0.05), but the effects of genotype on BA and NCCB were statistically insignificant (p > 0.05). In the E-II, the effect of wintering altitude on beehive weight was found to be statistically significant (p < 0.05), while its effect on the NCCB was statistically insignificant (p > 0.05). The wintering losses in the highland and lowland groups in E-I were determined to be 25% and 62.5% respectively. In contrast to this result, no loss was observed in E-II for both altitudes. In E-I, the wintering losses for both OSF and NBF groups were the same (43.75%). In conclusion, under subtropical climatic conditions, due to variations from year to year, honeybee colonies can be wintered more successfully in highland areas with OSF bottom board type. (Author)

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

National Research Council Canada - National Science Library

Moore, Lorna

1998-01-01

.... Results indicated that the effects of the menstrual cycle were modest. In year 2, we evaluated the safety and efficacy of administering an a-adrenergic blocker and made selected observations during a brief exposure to an altitude of 4300 m...

High Altitude Clear Air Turbulence Project

Data.gov (United States)

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

Temporal and spatial changes in Western Himalayan firn line altitudes from 1998 to 2009

Science.gov (United States)

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

[Relationship between baroreflex function and training effects on altitude training].

Science.gov (United States)

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.

The performance of Dräger Oxylog ventilators at simulated altitude.

Science.gov (United States)

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.

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...

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

Science.gov (United States)

Morris, C. E. K., Jr.

1983-01-01

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

Stress and nurses' horizontal mobbing: moderating effects of group identity and group support.

Science.gov (United States)

Topa, Gabriela; Moriano, Juan A

2013-01-01

Horizontal mobbing is a process of systematic and repeated aggression towards a worker by coworkers. Among others, stress has been pointed out as one of the antecedents that favors the onset of horizontal mobbing, whereas group support to the target could act as a buffer. Moreover, the social identity approach emphasizes that group identity is an antecedent of group support. This study explores the interaction of group support and group identity in the explanation of horizontal mobbing in a sample (N = 388) of registered nurses and licensed practical nurses employed at two large hospitals in Madrid and Navarre (Spain). The results show that stress is positively associated to horizontal mobbing, whereas group support and group identity were negative predictors of horizontal mobbing. Furthermore, the combination of low group identity and low group support precipitated HM among nurses. Copyright © 2013 Elsevier Inc. All rights reserved.

Low-resolution ship detection from high-altitude aerial images

Science.gov (United States)

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

2018-02-01

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

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.

Positive Association of D Allele of ACE Gene With High Altitude Pulmonary Edema in Indian Population.

Science.gov (United States)

Bhagi, Shuchi; Srivastava, Swati; Tomar, Arvind; Bala Singh, Shashi; Sarkar, Soma

2015-06-01

High altitude pulmonary edema (HAPE) is a potentially fatal high altitude illness occurring as a result of hypobaric hypoxia with an unknown underlying genetic mechanism. Recent studies have shown a possible association between HAPE and polymorphisms in genes of the renin-angiotensin-aldosterone system (RAAS), which play a key role in sensitivity of an individual toward HAPE. For the present investigation, study groups consisted of HAPE patients (HAPE) and acclimatized control subjects (rCON). Four single-nucleotide polymorphisms (SNPs) were genotyped using restriction fragment length polymorphism (RFLP) analysis in genes of the RAAS pathway, specifically, renin (REN) C(-4063)T (rs41317140) and RENi8-83 (rs2368564), angiotensin (AGT) M(235)T (rs699), and angiotensin-converting enzyme (ACE) insertion/deletion (I/D) (rs1799752). Only the I/D polymorphism of the ACE gene showed a significant difference between the HAPE and rCON groups. The frequency of the D allele was found to be significantly higher in the HAPE group. Arterial oxygen saturation levels were significantly lower in the HAPE group compared with the rCON group and also decreased in the I/D and D/D genotypes compared with the I/I genotype in these groups. The other polymorphisms occurring in the REN and AGT genes were not significantly different between the 2 groups. These findings demonstrate a possible association of the I/D polymorphism of the ACE gene with the development of HAPE, with D/D being the at-risk genotype. Copyright © 2015 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

Observation of a 27-day solar signature in noctilucent cloud altitude

Science.gov (United States)

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.

A method for sampling microbial aerosols using high altitude balloons.

Science.gov (United States)

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

2014-12-01

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

Moderation: an alternative to restraint as a mode of weight self-regulation.

Science.gov (United States)

Stotland, S

2012-12-01

This study considered two types of eating and weight self-regulation, in five groups, including four types of weight controllers and one non-dieting group. New scales were developed to measure eating moderation and restraint. Moderation was largely uncorrelated with restraint in 4 groups and had a fairly strong positive relation in 1 group. The moderation scale was unrelated to the Dutch Eating Behavior Questionnaire (DEBQ) restraint scale and the Three Factor Eating Questionnaire (TFEQ) rigid restraint subscale and weakly positively related to TFEQ flexible restraint. The restraint scale was strongly correlated to the DEBQ restraint scale, and to both flexible and rigid restraint subscales of the TFEQ. Across the five groups, moderation had exclusively positive relationships with attitude, behavior and emotion variables, while restraint had primarily negative relationships. The study supports moderation as a new dimension of weight self-regulation, independent of restraint. The new measures of moderation and restraint can be used together in research on the processes of change in weight management. Copyright © 2012 Elsevier Ltd. 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.

Moderate-intensity aerobic exercise improves sleep quality in men older adults

Directory of Open Access Journals (Sweden)

Shams Amir

2013-01-01

Full Text Available The purpose of present research was to investigate the effect of low and moderate intensity aerobic exercises on sleep quality in older adults. The statistical sample included 45 volunteer elderly men with age range of 60-70 years old that divided randomly in two experimental groups (aerobic exercise with low and moderate intensity and one control group. The maximum heart rate (MaxHR of subjects was obtained by subtracting one's age from 220. Furthermore, based on aerobic exercise type (40-50% MaxHR for low intensity group and 60-70% MaxHR for moderate intensity group the target MaxHR was calculated for each subject. The exercise protocol consisted of 8 weeks aerobic exercises (2 sessions in per-week based on Rockport one-mile walking/running test and the control group continued their daily activities. All subjects in per-test and post-test stages were completed the Petersburg Sleep Quality Index (PSQI. Results in post-test stage showed that there were significant differences between control and experimental groups in sleep quality and its components (P<0.05. Also, the Tukey Post Hoc showed that the moderate intensity group scores in sleep quality and its components were better than other groups (P<0.05. Finally, the low intensity group scores were better than control group (P<0.05. Generally, the present research showed that the aerobic exercises with moderate intensity have a positive and significant effect on sleep quality and its components. Thus, based on these findings, the moderate intensity aerobic exercises as a useful and medical method for improve the sleep quality among community older adults was recommended.

ModerateDrinking.com and Moderation Management: Outcomes of a randomized clinical trial with non-dependent problem drinkers1

Science.gov (United States)

Hester, Reid K.; Delaney, Harold D.; Campbell, William

2011-01-01

Objective To evaluate the effectiveness of a web-based protocol, Moderate Drinking (MD) (www.moderatedrinking.com) combined with use of the online resources of Moderation Management (MM) (www.moderation.org) as opposed to the use of the online resources of MM alone. Method We randomly assigned 80 problem drinkers to either the experimental or control group with follow-ups at 3, 6, and 12 months. Results Seventy-five participants (94%) had outcome data at one or more follow-up points and 59 (73%) were assessed at all three follow-ups. Comparing baseline measures to the average outcomes at follow-ups indicated a significant overall reduction in both groups in alcohol-related problems and consumption variables. Compared to the control group, the experimental group had better outcomes on percent days abstinent (PDA). There was an interaction between intensity of drinking at baseline and treatment in determining outcomes assessing drinking. Less heavy drinkers in the experimental group had better outcomes on log Mean BAC per drinking day compared to the control group. Heavier drinkers did not differentially benefit from the MD program on this measure. Mixed model analyses in general corroborated these outcomes. Conclusion The outcome data provide partial evidence for the effectiveness of the MD web application combined with MM, compared to the effectiveness of the resources available online at MM by themselves. PMID:21319896

Range Reference Atmosphere 0-70 Km Altitude. Kwajalein Missile Range, Kwajalein, Marshall Islands

Science.gov (United States)

1982-01-01

DOCUMENT 360-82 KWAJALEIN MISSILE RANGE KWAJALEIN, MARSHALL ISLANDS RANGE REFERENCE ATMOSPHERE 0-70 KM ALTITUDE, C00 L’’I METEOROLOGY GROUP .RANGE...34Reference Atmosphere (Part 1), Kwajale 4n Missile Range, Kwajalein, Marshall Islands ," ADA002664. * 19. KEY WORDS (Continue on revorsae d. If necoeewy...CLASSIFICATION OF TIlS PAGE (Whe~n Data EnterecD -v DOCUMENT 360-82 Vo- KWAJALEIN MISSILE RANGE KWAJALEIN, MARSHALL ISLANDS RANGE REFERENCE ATMOSPHERE 0-70 km

Altitude training for elite endurance performance: a 2012 update.

Science.gov (United States)

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.

Altitude training and haemoglobin mass from the optimised carbon monoxide rebreathing method determined by a meta-analysis.

Science.gov (United States)

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.

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...

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

Directory of Open Access Journals (Sweden)

Chun Guo

2015-12-01

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

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

Science.gov (United States)

Ivy, Catherine M; Scott, Graham R

2015-08-01

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

Pituitary, gonadal and adrenal hormones after prolonged residence at extreme altitude in man.

Science.gov (United States)

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.

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

Directory of Open Access Journals (Sweden)

Sheng Li Hu

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

Influence of altitude on vitamin D and bone metabolism of lactating sheep and goats.

Science.gov (United States)

Kohler, M; Leiber, F; Willems, H; Merbold, L; Liesegang, A

2013-11-01

This study investigated the influence of alpine grazing on vitamin D (vitD) and bone metabolism in sheep and goats. Two groups of five adult lactating East Friesian milk sheep and Saanen dairy goats were kept on pastures at 2,000 to 2,600 m a.s.l. (SA: sheep alpine; GA: goats alpine) and 400 m a.s.l. (SL: sheep lowland; GL: goats lowland). The animals were milked twice daily and the milk yield was measured. Blood, milk, skin, and forage samples were collected and the left metatarsi were measured with peripheral quantitative computed tomography. The relative humidity and air temperature were recorded and the ultraviolet B (UVB) radiation was measured with a solar meter at both research stations. In addition, animals from the alpine group were equipped with a global positioning system receiver. The UVB radiation was higher at the alpine station (Psheep compared to goats and the 25(OH)D3 concentration in serum increased in all four groups but was higher in the alpine groups during the experiment. In addition, no differences in 7-dehydrocholesterol (7-DHC) concentrations in the skin at high altitude and lowland groups were detectable. However the 7-DHC concentrations in the skin of sheep were less than a tenth of the concentrations in the skin of goats and were nearly not detectable. In both groups SA and SL bone strength index increased during the trial (P=0.043). Bone strength index was lower in GA compared to GL at wk 12 (P=0.047). Mean serum Ca concentrations were higher and P concentrations were lower in the alpine groups than in the lowland groups (P=0.047). In both groups SA and GA the distance travelled increased during the trial. In conclusion, no effect of altitude on vitD status, vitD milk concentration and bone strength could be detected. Both sheep and goats are able to produce vitD in the skin, but sheep depend more on vitD intake with feedstuff, whereas goats rely more on cutaneous vitD production.

A randomly-controlled study on the cardiac function at the early stage of return to the plains after short-term exposure to high altitude.

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Qiquan Zhou

Full Text Available High altitude acclimatization and adaptation mechanisms have been well clarified, however, high altitude de-adaptation mechanism remains unclear. In this study, we conducted a controlled study on cardiac functions in 96 healthy young male who rapidly entered the high altitude (3700 m and returned to the plains (1500 m after 50 days. Ninety eight healthy male who remained at low altitude were recruited as control group. The mean pulmonary arterial pressure (mPAP, left ventricular ejection fraction (LVEF, left ventricular fraction shortening (LVFS, cardiac function index (Tei index were tested. Levels of serum creatine kinase isoform MB (CK-MB, lactate dehydrogenase isoenzyme-1 (LDH-1, endothelin-1 (ET-1, nitrogen oxide (NO, serum hypoxia-inducible factor-1α (HIF-1α, 8-iso-prostaglandin F(2α (8-iso PGF(2α, superoxide dismutase (SOD and malonaldehyde (MDA were measured at an altitude of 3700 m and 1500 m respectively. The results showed that after short-term exposure to high altitude mPAP and Tei index increased significantly, while LVEF and LVFS decreased significantly. These changes were positively correlated with altitude. On the 15(th day after the subjects returned to low altitude, mPAP, LVEF and LVFS levels returned to the same level as those of the control subjects, but the Tei index in the returned subjects was still significantly higher than that in the control subjects (P<0.01. We also found that changes in Tei index was positively correlated with mPAP, ET-1, HIF-1α and 8-iso PGF(2α levels, and negatively correlated with the level of NO, LVEF, LVFS, CK-MB and LDH-1. These findings suggest that cardiac function de-adapts when returning to the plains after short-term exposure to high altitude and the function recovery takes a relatively long time.

Cold moderator test facilities working group

International Nuclear Information System (INIS)

Bauer, Guenter S.; Lucas, A. T.

1997-09-01

The working group meeting was chaired by Bauer and Lucas.Testing is a vital part of any cold source development project. This applies to specific physics concept verification, benchmarking in conjunction with computer modeling and engineering testing to confirm the functional viability of a proposed system. Irradiation testing of materials will always be needed to continuously extend a comprehensive and reliable information database. An ever increasing worldwide effort to enhance the performance of reactor and accelerator based neutron sources, coupled with the complexity and rising cost of building new generation facilities, gives a new dimension to cold source development and testing programs. A stronger focus is now being placed on the fine-tuning of cold source design to maximize its effectiveness in fully exploiting the facility. In this context, pulsed spallation neutron sources pose an extra challenge due to requirements regarding pulse width and shape which result from a large variety of different instrument concepts. The working group reviewed these requirements in terms of their consequences on the needs for testing equipment and compiled a list of existing and proposed facilities suitable to carry out the necessary development work.

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

Science.gov (United States)

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

1956-01-01

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

Mast cells in the human lung at high altitude

Science.gov (United States)

Heath, Donald

1992-12-01

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

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

Science.gov (United States)

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

2008-09-01

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

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

Science.gov (United States)

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.

ONLINE VS OFFLINE: DOES CITY IMAGE MODERATING COMPARISON BETWEEN INFLUENCE PERCEIVED BLOG INFORMATION AND REFERENCE GROUP TOWARD TOURIST VISIT INTENTION?

Directory of Open Access Journals (Sweden)

Angga Pandu Wijaya

2017-03-01

Full Text Available This research aims to investigating the phenomenon of perceived blog information, reference group, image of a city, and tourists’ intention to visit particular places. Perceived blog information is the online source, while the offline one is reference group. This is the first study comparing on online and offline information influence tourists’ intention to visit particular places. Samples are obtained through an electronic questionnaire involving 177 respondents and analyzed by using PLS-SEM. The results reveal that perceived blog information and reference group significantly influence image of the city and the intention to visit tourism destination. Image of the city moderate the relationship between independent and dependent variables partially. The influence of perceived blog information is greater than the reference group. It is indicates that online information is more influential. The stakeholders of tourism sector can utilize blog in increasing the number of visitors.

Effects of core models and neutron energy group structures on xenon oscillation in large graphite-moderated reactors

International Nuclear Information System (INIS)

Yamasita, Kiyonobu; Harada, Hiroo; Murata, Isao; Shindo, Ryuichi; Tsuruoka, Takuya.

1993-01-01

Xenon oscillations of large graphite-moderated reactors have been analyzed by a multi-group diffusion code with two- and three-dimensional core models to study the effects of the geometric core models and the neutron energy group structures on the evaluation of the Xe oscillation behavior. The study clarified the following. It is important for accurate Xe oscillation simulations to use the neutron energy group structure that describes well the large change in the absorption cross section of Xe in the thermal energy range of 0.1∼0.65 eV, because the energy structure in this energy range has significant influences on the amplitude and the period of oscillations in power distributions. Two-dimensional R-Z models can be used instead of three-dimensional R-θ-Z models for evaluation of the threshold power of Xe oscillation, but two-dimensional R-θ models cannot be used for evaluation of the threshold power. Although the threshold power evaluated with the R-θ-Z models coincides with that of the R-Z models, it does not coincide with that of the R-θ models. (author)

Thoraco-abdominal coordination and performance during uphill running at altitude.

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Eva Bernardi

Full Text Available Running races on mountain trails at moderate-high altitude with large elevation changes throughout has become increasingly popular. During exercise at altitude, ventilatory demands increase due to the combined effects of exercise and hypoxia.To investigate the relationships between thoraco-abdominal coordination, ventilatory pattern, oxygen saturation (SpO2, and endurance performance in runners during high-intensity uphill exercise.Fifteen participants (13 males, mean age 42±9 yrs ran a "Vertical Kilometer," i.e., an uphill run involving a climb of approximately 1000 m with a slope greater than 30%. The athletes were equipped with a portable respiratory inductive plethysmography system, a finger pulse oximeter and a global positioning unit (GPS. The ventilatory pattern (ventilation (VE, tidal volume (VT, respiratory rate (RR, and VE/VT ratio, thoraco-abdominal coordination, which is represented by the phase angle (PhA, and SpO2 were evaluated at rest and during the run. Before and after the run, we assessed respiratory function, respiratory muscle strength and the occurrence of interstitial pulmonary edema by thoracic ultrasound.Two subjects were excluded from the respiratory inductive plethysmography analysis due to motion artifacts. A quadratic relationship between the slope and the PhA was observed (r = 0.995, p = 0.036. When the slope increased above 30%, the PhA increased, indicating a reduction in thoraco-abdominal coordination. The reduced thoraco-abdominal coordination was significantly related to reduced breathing efficiency (i.e., an increased VE/VT ratio; r = 0.961, p = 0.038 and SpO2 (r = -0.697, p<0.001. Lower SpO2 values were associated with lower speeds at 20%≥slope≤40% (r = 0.335, p<0.001 for horizontal and r = 0.36, p<0.001 for vertical. The reduced thoraco-abdominal coordination and consequent reduction in SpO2 were associated with interstitial pulmonary edema.Reductions in thoraco-abdominal coordination are associated

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...

Impact of a Newly Constructed Motor Vehicle Road on Altitude Illness in the Nepal Himalayas.

Science.gov (United States)

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.

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

Science.gov (United States)

Riley, Callum James; Gavin, Matthew

2017-06-01

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

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

Science.gov (United States)

Bhasuran, Balu; Subramanian, Devika; Natarajan, Jeyakumar

2018-05-02

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

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

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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.

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

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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...

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

Science.gov (United States)

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

2014-12-01

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

Carcass yields of two different strains of ducks raised in different altitude

Science.gov (United States)

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.

Science.gov (United States)

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.

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

Occupational health of miners at altitude: adverse health effects, toxic exposures, pre-placement screening, acclimatization, and worker surveillance.

Science.gov (United States)

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

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 R_c/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

Lessons Learned for Online Health Community Moderator Roles: A Mixed-Methods Study of Moderators Resigning From WebMD Communities

Science.gov (United States)

Marmor, Rebecca; Jiang, Xiaoqian

2016-01-01

Background Online health community (OHC) moderators help facilitate conversations and provide information to members. However, the necessity of the moderator in helping members achieve goals by providing the support they need remains unclear, with some prior research suggesting that moderation is unnecessary or even harmful for close-knit OHCs. Similarly, members’ perceptions of moderator roles are underexplored. Starting January of 2013, WebMD moderators stopped working for WebMD communities. This event provided an opportunity for us to study the perceived role of moderators in OHCs. Objective We examine the OHC members’ perception on OHC moderators by studying their reactions toward the departure of moderators in their communities. We also analyzed the relative posting activity on OHCs before and after the departure of moderators from the communities among all members and those who discussed moderators’ departures. Methods We applied a mixed-methods approach to study the posts of all 55 moderated WebMD communities by querying the terms relating to discussions surrounding moderators’ disappearance from the WebMD community. We performed open and axial coding and affinity diagramming to thematically analyze patients’ reactions to the disappeared moderators. The number of posts and poster groups (members and moderators) were analyzed over time to understand posting patterns around moderators’ departure. Results Of 821 posts retrieved under 95 threads, a total of 166 open codes were generated. The codes were then grouped into 2 main themes with 6 total subthemes. First, patients attempted to understand why moderators had left and what could be done to fill the void left by the missing moderators. During these discussions, the posts revealed that patients believed that moderators played critical roles in the communities by making the communities vibrant and healthy, finding solutions, and giving medical information. Some patients felt personally attached

Why should we bother with assessment moderation?

Science.gov (United States)

Smith, Colleen

2012-08-01

Assessment moderation is a significant component of a quality education system. How this practice is conceptualised, applied to the assessment process and embedded in teaching and learning, influence the quality of nurse education programmes. This paper challenges the traditional view that moderation is confined to what happens at the time of assessment which is evident in the use of language such as pre-moderation and post-moderation practice. It critiques traditional moderation practices such as double marking, applying assessment criteria and standards and assigning marks and grades and argues that these practices don't do justice to the complexity of assessment. It calls for a whole of course approach to moderation based on a set of principles which encompass constructive alignment, a community of practice group, the subjective nature of assessment and a reflective quality improvement cycle. Copyright © 2011 Elsevier Ltd. All rights reserved.

Prognosis moderates the engagement-outcome relationship in unguided cCBT for depression: A proof of concept for the prognosis moderation hypothesis.

Science.gov (United States)

Forand, Nicholas R; Huibers, Marcus J H; DeRubeis, Robert J

2017-05-01

Understanding how treatments work is a goal of psychotherapy research, however the strength of relationships between therapy processes and outcomes is inconsistent. DeRubeis, Cohen, et al. (2014) proposed that process-outcome relationships are moderated by patient characteristics. These "patient response patterns" (PRPs) indicate individuals' responsiveness to the active ingredients of treatment. Given the same quality of therapy, one individual may receive more benefit than another depending on their PRP. The "prognosis moderation hypothesis" states that PRPs can be defined by pretreatment prognostic indicators. Medium prognosis groups ("pliant-like") will have stronger process-outcome relationships than good ("easy-like") or poor ("challenging-like") groups. N = 190 individuals received unguided computerized CBT. They were 58% women, aged 44.7 years. Engagement with the cCBT program was the process variable. PRPs were defined by predicted scores from a prognostic regression model. Outcomes were BDI scores at 3, 6, and 12 months. "Easy-like," "pliant-like" and "challenging-like" groups were created and the engagement-outcome relationship was assessed as a function of group. Engagement-outcome correlations by PRP were: easy-like, r = -.27 (p moderator of the engagement-outcome relationship. Results were similar at 6 months but faded at 12. The engagement-outcome relationship varied as a function of prognosis, providing support for the prognosis moderation hypothesis. The "pliant-like" group appeared most sensitive to treatment procedures. Future research is needed to refine the methods for identifying PRPs. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

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

Attention indicator dynamics of qualified climbers influenced by hypoxic training during the overcoming various altitude levels of Mount Elbrus

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Andriy Kiyko

2017-08-01

Full Text Available Purpose: to determine the effect of hypoxic training on the attention indicators at different altitudes when crossing the Mount Elbrus. Material & Methods: the study of various attention indicators with the participation of control (n=16 and experimental (n=12 groups with the use of interval hypoxic training (IHT in the 15–15 mode with breathing through the system into a confined space in the experimental group and using the methods of mathematical statistics are carried out. Result: studies have made it possible to determine that the use of the regime of discontinuous hypoxia 15–15 in the training process of the pre-competitive period contribute to an increase in attention rates that affect adaptation to the load under hypoxia conditions. Conclusion: results of the conducted studies indicate that the use of IHT in the 15–15 mode in the period before the ascent to Mount Elbrus allows to significantly increase the attention rates of qualified climbers at different altitude levels.

An anxiety, personality and altitude symptomatology study during a 31-day period of hypoxia in a hypobaric chamber (experiment 'Everest-Comex 1997').

Science.gov (United States)

Nicolas, M; Thullier-Lestienne, F; Bouquet, C; Gardette, B; Gortan, C; Joulia, F; Bonnon, M; Richalet, J P; Therme, P; Abraini, J H

1999-12-01

Extreme environmental situations are useful tools for the investigation of the general processes of adaptation. Among such situations, high altitude of more than 3000 m produces a set of pathological disorders that includes both cerebral (cAS) and respiratory (RAS) altitude symptoms. High altitude exposure further induces anxiety responses and behavioural disturbances. The authors report an investigation on anxiety responses, personality traits, and altitude symptoms (AS) in climbers participating in a 31-day period of confinement and gradual decompression in a hypobaric chamber equivalent to a climb from sea-level to Mount Everest (8848 m altitude). Personality traits, state-trait anxiety, and AS were assessed, using the Cattell 16 Personality Factor questionnaire (16PF), the Spielberger's State-Trait Anxiety Inventory (STAI), and the Lake Louise concensus questionnaire. Results show significant group effect for state-anxiety and AS; state-anxiety and AS increased as altitude increased. They also show that state-type anxiety shows a similar time-course to cAS, but not RAS. Alternatively, our results demonstrate a significant negative correlation between Factor M of the 16PF questionnaire, which is a personality trait that ranges from praxernia to autia. In contrast, no significant correlation was found between personality traits and AS. This suggests that AS could not be predicted using personality traits and further support that personality traits, such as praxernia (happening sensitivity), could play a major role in the occurrence of state-type anxiety responses in extreme environments. In addition, the general processes of coping and adaptation in individuals participating in extreme environmental experiments are discussed.

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.

Variability of Diurnal Temperature Range During Winter Over Western Himalaya: Range- and Altitude-Wise Study

Science.gov (United States)

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.

Filamentation and light bullet formation dynamics in solid-state dielectric media with weak, moderate and strong anomalous group velocity dispersion

International Nuclear Information System (INIS)

Gražulevičiūtė, I; Garejev, N; Majus, D; Tamošauskas, G; A Dubietis; Jukna, V

2016-01-01

We present a series of measurements, which characterize filamentation dynamics of intense ultrashort laser pulses in the space–time domain, as captured by means of three-dimensional imaging technique in sapphire and fused silica, in the wavelength range of 1.45–2.25 μm, accessing the regimes of weak, moderate and strong anomalous group velocity dispersion (GVD). In the regime of weak anomalous GVD (at 1.45 μm), pulse splitting into two sub-pulses producing a pair of light bullets with spectrally shifted carrier frequencies in both nonlinear media is observed. In contrast, in the regimes of moderate (at 1.8 μm) and strong (at 2.25 μm) anomalous GVD we observe notably different transient dynamics, which however lead to the formation of a single self-compressed quasistationary light bullet with an universal spatiotemporal shape comprised of an extended ring-shaped periphery and a localized intense core that carries the self-compressed pulse. (paper)

Filamentation and light bullet formation dynamics in solid-state dielectric media with weak, moderate and strong anomalous group velocity dispersion

Science.gov (United States)

Gražulevičiūtė, I.; Garejev, N.; Majus, D.; Jukna, V.; Tamošauskas, G.; Dubietis, A.

2016-02-01

We present a series of measurements, which characterize filamentation dynamics of intense ultrashort laser pulses in the space-time domain, as captured by means of three-dimensional imaging technique in sapphire and fused silica, in the wavelength range of 1.45-2.25 μm, accessing the regimes of weak, moderate and strong anomalous group velocity dispersion (GVD). In the regime of weak anomalous GVD (at 1.45 μm), pulse splitting into two sub-pulses producing a pair of light bullets with spectrally shifted carrier frequencies in both nonlinear media is observed. In contrast, in the regimes of moderate (at 1.8 μm) and strong (at 2.25 μm) anomalous GVD we observe notably different transient dynamics, which however lead to the formation of a single self-compressed quasistationary light bullet with an universal spatiotemporal shape comprised of an extended ring-shaped periphery and a localized intense core that carries the self-compressed pulse.

A dictionary of altitudes in the United States (second edition)

Science.gov (United States)

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.

Cerebrovascular reactivity among native-raised high altitude residents: an fMRI study

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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.

Quantifying altitude of human habitation in studies of human health using geographical name server data

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

Science.gov (United States)

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

2011-12-01

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

Dry deposition of sulphur at a high-altitude background station in South Africa

CSIR Research Space (South Africa)

Zunckel, M

1999-10-01

Full Text Available station also plays a role in the observed day-to-day variation as pollutants are trapped immediately below this layer. The pressure difference between the base of the absolutely stable layer and the surface pressure at Ben MacDhui is used to indicate... AT A HIGH-ALTITUDE BACKGROUND STATION IN SOUTH AFRICA MARK ZUNCKEL1;2 , STUART PIKETH1 and TALI FREIMAN1 1 Climatology Research Group, University of Witwatersrand, Johannesburg, South Africa; 2 CSIR Environmentek, P.O. Box 17001, Congella, South Africa...

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

Science.gov (United States)

Snyder, David D.

2012-01-01

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

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

NARCIS (Netherlands)

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

2012-01-01

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

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

NARCIS (Netherlands)

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

2012-01-01

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

Agroforestry systems, nutrients in litter and microbial activity in soils cultivated with coffee at high altitude

Directory of Open Access Journals (Sweden)

Krystal de Alcantara Notaro

2014-04-01

Full Text Available Agroforestry systems are an alternative option for sustainable production management. These systems contain trees that absorb nutrients from deeper layers of the soil and leaf litter that help improve the soil quality of the rough terrain in high altitude areas, which are areas extremely susceptible to environmental degradation. The aim of this study was to characterize the stock and nutrients in litter, soil activity and the population of microorganisms in coffee (Coffea arabica L. plantations under high altitude agroforestry systems in the semi-arid region of the state of Pernambuco, Brazil. Samples were collected from the surface litter together with soil samples taken at two depths (0-10 and 10-20 cm from areas each subject to one of the following four treatments: agroforestry system (AS, native forest (NF, biodynamic system (BS and coffee control (CT.The coffee plantation had been abandoned for nearly 15 years and, although there had been no management or harvesting, still contained productive coffee plants. The accumulation of litter and mean nutrient content of the litter, the soil nutrient content, microbial biomass carbon, total carbon, total nitrogen, C/N ratio, basal respiration, microbial quotient, metabolic quotient and microbial populations (total bacteria, fluorescent bacteria group, total fungi and Trichoderma spp. were all analyzed. The systems thatwere exposed to human intervention (A and BS differed in their chemical attributes and contained higher levels of nutrients when compared to NF and CT. BS for coffee production at high altitude can be used as a sustainable alternative in the high altitude zones of the semi-arid region in Brazil, which is an area that is highly susceptible to environmental degradation.

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

Science.gov (United States)

Robertson, Bill

2017-01-01

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

Experimental StudyHigh Altitude Forced Convective Cooling of Electromechanical Actuation Systems

Science.gov (United States)

2016-01-01

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

Athletic altitude training protocols and their application in preparation for mountainous operations.

Science.gov (United States)

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...

Group Milieu in systemic and psychodynamic group therapy

DEFF Research Database (Denmark)

Lau, Marianne Engelbrecht; Kristensen, Ellids

Objectives: A recent meta-analysis also concluded that psychotherapeutic approaches are beneficial for adult with a history of CSA and maintained for at least six months follow-up. The results suggest that different characteristics of therapy moderate the therapeutic outcome. We found in a random......Objectives: A recent meta-analysis also concluded that psychotherapeutic approaches are beneficial for adult with a history of CSA and maintained for at least six months follow-up. The results suggest that different characteristics of therapy moderate the therapeutic outcome. We found...... in a randomized study of systemic versus psychodynamic group therapy, that the short-term outcome for patients who received systemic group psychotherapy was significantly better than the outcome for patients who received psychodynamic group psychotherapy. The current study assessed the group milieu in both groups....... Methods: This randomized prospective study included 106 women: 52 assigned to psychodynamic group psychotherapy and 54 assigned to systemic group psychotherapy. The Group Environment Scale (GES) was filled in the mid phase of therapy and analysed in three dimensions and 10 subscales. Results: The systemic...

Reproductive performance of peranakan ongole (PO) bull at different altitudes areas in Lampung province

Science.gov (United States)

Suretno, N. D.; Supriyatna, I.; Purwanto, B.; Priyanto, R.

2018-01-01

Peranakan Ongole (PO) cattle are famous for their bulls and known for their toughness, rapid growth and natural tolerance to tropical heat and disease resistance. This study was conducted to determine the reproductive performance of PO bull in some altitude in Lampung Province. A total of PO bulls used were 48 heads, with age three to four years. The variables observed were volume, consistency, pH, semen colour, concentration, mass movement, motility, percentage of living spermatozoa and abnormality. Data were collected during the rainy season and dry season, calculated with the average and standard deviation and then analyzed descriptively. Based on the macroscopic examination, Peranakan Ongole bull living in low temperature place had a normal semen volume, the consistency mostly watery to moderate, fresh semen pH is in the normal range and the color of semen are all normal both in the rainy and dry seasons. The results of microscopic examination showed that PO cattle had a good reproduction conditions at all three

Aspirated Compressors for High Altitude Engines, Phase I

Data.gov (United States)

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

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

Science.gov (United States)

1991-08-01

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

Altitude Testing of Large Liquid Propellant Engines

Science.gov (United States)

Maynard, Bryon T.; Raines, Nickey G.

2010-01-01

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

The airglow layer emission altitude cannot be determined unambiguously from temperature comparison with lidars

Science.gov (United States)

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.

Preliminary study on alterations of altitude road traffic in China from 2006 to 2013

Science.gov (United States)

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

Magnetic Pair Creation Attenuation Altitude Constraints in Gamma-Ray Pulsars

Science.gov (United States)

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.

Pulmonary decompression sickness at altitude: early symptoms and circulating gas emboli

Science.gov (United States)

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

NARCIS (Netherlands)

Lansdorp, B.; Williams, P.

2006-01-01

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

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

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.

Factors associated with poor balance ability in older adults of nine high-altitude communities.

Science.gov (United States)

Urrunaga-Pastor, Diego; Moncada-Mapelli, Enrique; Runzer-Colmenares, Fernando M; Bailon-Valdez, Zaira; Samper-Ternent, Rafael; Rodriguez-Mañas, Leocadio; Parodi, Jose F

2018-05-01

Poor balance ability in older adults result in multiple complications. Poor balance ability has not been studied among older adults living at high altitudes. In this study, we analysed factors associated with poor balance ability by using the Functional Reach (FR) among older adults living in nine high-altitude communities. Analytical cross-sectional study, carried out in inhabitants aged 60 or over from nine high-altitude Andean communities of Peru during 2013-2016. FR was divided according to the cut-off point of 8 inches (20.32 cm) and two groups were generated: poor balance ability (FR less or equal than 20.32 cm) and good balance ability (greater than 20.32 cm). Additionally, we collected socio-demographic, medical, functional and cognitive assessment information. Poisson regression models were constructed to identify factors associated with poor balance ability. Prevalence ratio (PR) with 95% confidence intervals (95CI%) are presented. A total of 365 older adults were studied. The average age was 73.0 ± 6.9 years (range: 60-91 years), and 180 (49.3%) participants had poor balance ability. In the adjusted Poisson regression analysis, the factors associated with poor balance ability were: alcohol consumption (PR = 1.35; 95%CI: 1.05-1.73), exhaustion (PR = 2.22; 95%CI: 1.49-3.31), gait speed (PR = 0.67; 95%CI: 0.50-0.90), having had at least one fall in the last year (PR = 2.03; 95%CI: 1.19-3.46), having at least one comorbidity (PR = 1.60; 95%CI: 1.10-2.35) and having two or more comorbidities (PR = 1.61; 95%CI: 1.07-2.42) compared to none. Approximately a half of the older adults from these high-altitude communities had poor balance ability. Interventions need to be designed to target these balance issues and prevent adverse events from concurring to these individuals. Copyright © 2018 Elsevier B.V. All rights reserved.

Time course of the hemoglobin mass response to natural altitude training in elite endurance cyclists.

Science.gov (United States)

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

OpenAIRE

Harald Pauli

2016-01-01

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

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

Directory of Open Access Journals (Sweden)

Juan Xiong

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

Moderate Psoriasis: A Proposed Definition.

Science.gov (United States)

Llamas-Velasco, M; de la Cueva, P; Notario, J; Martínez-Pilar, L; Martorell, A; Moreno-Ramírez, D

2017-12-01

The Psoriasis Area Severity Index (PASI) is the most widely used scale for assessing the severity of psoriasis and for therapeutic decision making. On the basis of the PASI score, patients have been stratified into 2 groups: mild disease and moderate-to-severe disease. To draft a proposal for the definition and characterization of moderate psoriasis based on PASI and Dermatology Life Quality Index (DLQI) scores. A group of 6 dermatologists with experience in the treatment of psoriasis undertook a critical review of the literature and a discussion of cases to draft a proposal. In order of priority, PASI, DLQI, and body surface area (BSA) are the parameters to be used in daily practice to classify psoriasis as mild, moderate, or severe. Severity should be assessed on the basis of a combined evaluation and interpretation of the PASI and DLQI. And 3, PASI and DLQI should carry equal weight in the determination of disease severity. On this basis, psoriasis severity was defined using the following criteria: mild, PASI15, independently of the DLQI score. A more precise classification of psoriasis according to disease severity will improve the risk-benefit assessment essential to therapeutic decision making in these patients. Copyright © 2017 AEDV. Publicado por Elsevier España, S.L.U. All rights reserved.

Low-altitude trapped protons at the geomagnetic equator

Science.gov (United States)

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.

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

Science.gov (United States)

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

2018-04-01

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

Characteristic analysis on moderating material for obtaining epithermal neutron beam

International Nuclear Information System (INIS)

Jiang Xinbiao; Chen Da; Zhang Ying

2000-01-01

The one dimension discrete coordinates transport code ANISN was used to calculate three-group constants of 11 elements which could be used to consist moderating epithermal neutron material of beam. Moderating character of simple substances, compounds and mixtures consisted of the optimized elements analyzed three kinds of moderating materials were optimized for epithermal neutron beam

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.

[Co-occurrence of soil fauna communities with changes in altitude on the northern slope of Changbai Mountain].

Science.gov (United States)

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.

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)

Water-Vapor Raman Lidar System Reaches Higher Altitude

Science.gov (United States)

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

CERN Document Server

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

2005-01-01

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

Moderate Versus Light Pressure Massage Therapy Leads to Greater Weight Gain in Preterm Infants

Science.gov (United States)

Field, Tiffany; Diego, Miguel A.; Hernandez-Reif, Maria; Deeds, Osvelia; Figuereido, Barbara

2007-01-01

Sixty-eight preterm infants (M GA=3Owks.) were randomly assigned to a moderate or to a light pressure massage therapy group to receive 15 massages 3 times per day for 5 days. Behavior state, stress behaviors and heart rate were recorded for 15 minutes before and during the first 15-minute therapy session. Weight gain was recorded over the 5 day therapy period. The moderate versus light pressure massage group gained significantly more weight per day. During the behavior observations the moderate versus light pressure massage group showed significantly lower increases from the pre-session to the session recording on: 1) active sleep; 2) fussing; 3) crying; 4) movement; and 5) stress behavior (hiccupping). They also showed a smaller decrease in deep sleep, a greater decrease in heart rate and a greater increase in vagal tone. Thus, the moderate pressure massage therapy group appeared to be more relaxed and less aroused than the light pressure massage group which may have contributed to the greater weight gain of the moderate pressure massage therapy group. PMID:17138310

Changes of body fluid and hematology in toad and their rehabilitation following intermittent exposure to simulated high altitude

Science.gov (United States)

Biswas, H. M.; Boral, M. C.

1986-06-01

Three groups of adult male toads were exposed intermittently in a decompression chamber for a daily period of 4 and 8 hours at a time for 6 consecutive days to an “altitude” of 12,000; 18,000 and 24,000 feet (3658; 5486; 7315 m) respectively. Most of the exposed animals were sacrificed immediately after the last exposure, but only a few animals experiencing 8 hours of exposure were sacrificed after a further 16 hours of exposure at normal atmospheric pressure. Eight hours of daily exposure for 6 days causes a decrease of body fluids and an increase of hematological parameters in all the altitude exposed animals compared with to the changes noted in the animals having 4 hours of daily exposure for 6 days at the same altitude levels. The animals that were exposed to pressures equivalent to altitudes of 12,000 and 18,000 feet daily for 8 hours were found to return nearly to their normal body fluids and hematological balance after 16 hours of exposure to normal atmospheric pressure, whereas the animals exposed for a similar period at an equivalent 24,000 feet failed to get back their normal balance of body fluids and hematology after 16 hours of exposure at normal atmospheric pressure. The present experiment shows that the body weight loss and changes of body fluid and hematological parameters in the toad after exposure to simulated high altitude are due not only to dehydration, but suggest that hypoxia may also have a role.