EFFECTS OF HIGH ALTITUDE ON ENDOCRINE FUNCTION IN THE SHERPAS OF NEPAL

1978 ◽  
Vol 79 (1) ◽  
pp. 147-148 ◽  
Author(s):  
C. R. M. BANGHAM ◽  
P. H. HACKETT
Keyword(s):  
High Altitude ◽  
Reproductive Hormones ◽  
Fertility Rate ◽  
Endocrine Function ◽  
Serum Concentrations ◽  
The Andes ◽  
Lower Fertility ◽  
Low Altitude ◽  
Fertility Difference ◽  
And Control

*National Institute for Biological Standards and Control, Holly Hill, London, NW3 6RB and ‡Himalayan Rescue Association, P.O. Box 283, Kathmandu, Nepal (Received 23 May 1978) There is demographic evidence from studies in the Andes (James, 1966; Heer, 1967; Abelson, 1976) for lower fertility in high-altitude dwellers than in moderate- or low-altitude dwellers. In the Sherpas of Nepal, the completed fertility rate at high altitude (about 6·0) is appreciably less than that at lower altitudes (8·5; C. R. M. Bangham & J. M. Sacherer, unpublished observations). However, the physiological reasons (if any) for such a difference are obscure. The present study was carried out to test the hypothesis that such a fertility difference (between low- and high-altitude dwellers) is reflected in different serum concentrations of reproductive hormones. Sampling was carried out at altitudes of 4240 m in Khumbu, 2670 m in Pharak (south of Khumbu) and 1460 m in Kathmandu; the

scholarly journals Convergent changes in muscle metabolism depend on duration of high-altitude ancestry across Andean waterfowl

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Neal J Dawson ◽  
Luis Alza ◽  
Gabriele Nandal ◽  
Graham R Scott ◽  
Kevin G McCracken
Keyword(s):  
High Altitude ◽  
Flight Muscle ◽  
Muscle Metabolism ◽  
Mitochondrial Oxidative Phosphorylation ◽  
Evolutionary Time ◽  
Hexokinase Activity ◽  
Biochemical Pathways ◽  
The Andes ◽  
Hydroxyacyl Coa Dehydrogenase ◽  
Low Altitude

High-altitude environments require that animals meet the metabolic O2 demands for locomotion and thermogenesis in O2-thin air, but the degree to which convergent metabolic changes have arisen across independent high-altitude lineages or the speed at which such changes arise is unclear. We examined seven high-altitude waterfowl that have inhabited the Andes (3812–4806 m elevation) over varying evolutionary time scales, to elucidate changes in biochemical pathways of energy metabolism in flight muscle relative to low-altitude sister taxa. Convergent changes across high-altitude taxa included increased hydroxyacyl-coA dehydrogenase and succinate dehydrogenase activities, decreased lactate dehydrogenase, pyruvate kinase, creatine kinase, and cytochrome c oxidase activities, and increased myoglobin content. ATP synthase activity increased in only the longest established high-altitude taxa, whereas hexokinase activity increased in only newly established taxa. Therefore, changes in pathways of lipid oxidation, glycolysis, and mitochondrial oxidative phosphorylation are common strategies to cope with high-altitude hypoxia, but some changes require longer evolutionary time to arise.

scholarly journals Altitude conditions seem to determine the evolution of COVID-19 in Brazil

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
José Sebastião Cunha Fernandes ◽  
Ricardo Siqueira da Silva ◽  
Alexandre Christófaro Silva ◽  
Daniel Campos Villela ◽  
Vanessa Amaral Mendonça ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Correlation Analysis ◽  
High Altitude ◽  
Negative Correlation ◽  
Death Rate ◽  
Epidemiological Analysis ◽  
Future Studies ◽  
Tukey Test ◽  
Low Altitude ◽  
And Control

AbstractCOVID-19 is spreading rapidly in Brazil, a country of continental dimensions, but the incidence of the disease is showing to be very heterogeneous, affecting cities and regions differently. Thus, there is a gap regarding what factors would contribute to accentuate the differences in the incidence of COVID-19 among Brazilian cities. This work aimed to evaluate the effect of altitude on the incidence of COVID-19 in Brazilian cities. We analyzed the relative incidence (RI), the relative death rate (RDR) of COVID-19, and air relative humidity (RH) in all 154 cities in Brazil with a population above 200 thousand inhabitants, located between 5 and 1135 m in altitude. Pearson's correlation analysis was performed to compare a relationship between altitude with RI and RDR, and between RH with RI and RDR. Altitudes were classified into three classes [low (altitude ≤ 97 m a. s. l), middle (97 < altitude ≤ 795 m a. s. l), high (795 < altitude ≤ 1135 m a. s. l)] for the RI, RDR, and RH variables. To compare the three classes of altitude, analysis of variance (ANOVA) and Tukey test were used to compare averages (p < 0.05). Our epidemiological analysis found that the RI, RDR, and RH were lower in cities located in high altitudes (795 < altitude ≤ 1135 m a. s. l) when compared to the middle (97 < altitude ≤ 795 m a. s. l) and low (altitude ≤ 97 m a. s. l) cities altitudes. Furthermore, our study shows that there is a negative correlation between the incidence of COVID-19 with altitude and a positive correlation with RH in the cities analyzed. Brazilian cities with high altitude and low RH have lower RI and RDR from COVID-19. Thus, high altitude cities may be favorable to shelter people at risk. This study may be useful for understanding the behavior of SARS-CoV2, and start point for future studies to establish causality of environmental conditions with SARS-CoV2 contributing to the implementation of measures to prevent and control the spread of COVID-19.

scholarly journals Down Feather Structure Varies Between Low- and High-Altitude Torrent Ducks (Merganetta Armata) in the Andes

2017 ◽  
Author(s):  
Rebecca G. Cheek ◽  
Luis Alza ◽  
Kevin G. McCracken
Keyword(s):  
High Altitude ◽  
Environmental Conditions ◽  
Critical Role ◽  
Ambient Temperatures ◽  
The Andes ◽  
Significant Difference ◽  
General Constraints ◽  
Low Altitude ◽  
High Elevations ◽  
Two Populations

AbstractFeathers are one of the defining characteristics of birds and serve a critical role in thermal insulation and physical protection against the environment. Feather structure is known to vary among individuals, and it has been suggested that populations exposed to different environmental conditions may exhibit different patterns in feather structure. We examined both down and contour feathers from two populations of male Torrent Ducks (Merganetta armata) from Lima, Peru, including one high-altitude population from the Chancay-Huaral River at approximately 3500 meters (m) elevation and one low-altitude population from the Chillón River at approximately 1500 m. Down feather structure differed significantly between the two populations. Ducks from the high-altitude population had longer, denser down compared with low-altitude individuals. Contour feather structure varied greatly among individuals but showed no significant difference between populations. These results suggest that the innermost, insulative layer of plumage (the down), may have developed in response to lower ambient temperatures at high elevations. The lack of observable differences in the contour feathers may be due to the general constraints of the waterproofing capability of this outer plumage layer.ResumenEl plumaje es una característica que define a las aves y cumple roles críticos en el aislamiento térmico y protección física del ambiente. Se sabe que la estructura de las plumas varía ente individuos, y se ha sugerido que poblaciones expuestas a diferentes condiciones ambientales pueden exhibir diferentes patrones en la estructura de las plumas. En este estudio se examinaron tanto el plumón como las plumas de contorno de machos adultos del Pato de los Torrentes (Merganetta armata) de dos poblaciones, una en el río Chancay-Huaral a 3,500 msnm y otra en el río Chillón a 1,500 msnm, ubicadas en Lima, Perú. La estructura de los plumones difiere significativamente entre las dos poblaciones. Los patos de la población a grandes elevaciones tienen plumones largos, y densos comparados con los individuos de las partes bajas. La estructura de las plumas de contorno varía ampliamente entre individuos pero no muestra diferencias significativas entre poblaciones. Estos resultados sugieren que las diferencias entre las capas interiores de aislamiento del plumaje (plumón), haberse desarrollado como respuesta en ambientes de bajas temperaturas a grandes elevaciones. En cambio la falta de detectables diferencias en las plumas de contorno puede ser debido a la constante selección en la capacidad impermeable de la capa de plumas exteriores.

Simulation of thermal stress and control measures for rock-filled concrete dam in high-altitude and cold regions

2021 ◽  
Vol 230 ◽  
pp. 111721
Author(s):  
Yuxiang Zhang ◽  
Jianwen Pan ◽  
Xinjian Sun ◽  
Jijun Feng ◽  
Dengqiang Sheng ◽  
...  
Keyword(s):  
Thermal Stress ◽  
High Altitude ◽  
Control Measures ◽  
Concrete Dam ◽  
Cold Regions ◽  
And Control

Optical and gravito-inertial contributions to the perception and control of height in a simulated Low-Altitude flight context

Ergonomics ◽  
2021 ◽  
pp. 1-30
Author(s):  
F Denquin ◽  
J Foucher ◽  
S Pla ◽  
J. C Sarrazin ◽  
B. G Bardy
Keyword(s):  
Low Altitude ◽  
And Control

scholarly journals Effect of High-Altitude Environment on Driving Safety: A Study on Drivers’ Mental Workload, Situation Awareness, and Driving Behaviour

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Xinyan Wang ◽  
Wu Bo ◽  
Weihua Yang ◽  
Suping Cui ◽  
Pengzi Chu
Keyword(s):  
High Altitude ◽  
Situation Awareness ◽  
Mental Workload ◽  
Mediating Effect ◽  
Driving Safety ◽  
Risky Driving ◽  
Driving Behaviour ◽  
Driving Risk ◽  
Low Altitude ◽  
The Relationship

This study aims to analyze the effect of high-altitude environment on drivers’ mental workload (MW), situation awareness (SA), and driving behaviour (DB), and to explore the relationship among those driving performances. Based on a survey, the data of 356 lowlanders engaging in driving activities at Tibetan Plateau (high-altitude group) and 341 lowlanders engaging in driving activities at low altitudes (low-altitude group) were compared and analyzed. The results suggest that the differences between the two groups are noteworthy. Mental workload of high-altitude group is significantly higher than that of low-altitude group, and their situation awareness is lower significantly. The possibility of risky driving behaviours for high-altitude group, especially aggressive violations, is higher. For the high-altitude group, the increase of mental workload can lead to an increase on aggressive violations, and the situation understanding plays a full mediating effect between mental workload and aggressive violations. Measures aiming at the improvement of situation awareness and the reduction of mental workload can effectively reduce the driving risk from high-altitude environment for lowlanders.

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