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de Aquino Lemos, Valdir, Ronaldo Vagner Thomatieli dos Santos, Fabio Santos Lira, Bruno Rodrigues, Sergio Tufik und Marco Tulio de Mello. „Can High Altitude Influence Cytokines and Sleep?“ Mediators of Inflammation 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/279365.
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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.
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Tang, Yan Fei, Chao Ding, Ya Ping He, De Chuang Zhou und Jian Wang. „Studies on the Effect of Altitude on the Flammable Liquids' Flash Point“. Advanced Materials Research 908 (März 2014): 345–48. http://dx.doi.org/10.4028/www.scientific.net/amr.908.345.
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Presented in this paper is part of an experimental series conducted at different altitudes to investigate the influence of altitude on the flammable liquids flash point. The BS-1 closed bomb apparatus is used to measure the flash points of two flammable liquids (dimethylacetylamide (DMA) and RP-5 Jet A) in a hypobaric chamber under the altitude change from 4860 km to the sea level. The experimental results show that the flash points of DMA and Jet A decrease linearly with the increase in altitude in the low altitude region below the corresponding critical altitudes but non-linearly above. The critical altitudes for DMA and RP-5 Jet A are found to be 3 km and 3.83 km respectively. When the altitude reaches or surpasses the critical altitude, the flash point decreases rapidly. In particular, the flash point of the DMA exhibits a peculiar sudden transition above the critical altitude.
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PUTRA, HIRMAS FUADY, DHENOK SEKAR AMBARWATI, NURRIZKI MUBYRASIH und TERSI ALESTI. „Karakteristik Fisiologis Lumut pada Beberapa Ketinggian di Kawasan Gunung Tangkuban Perahu“. Jurnal Sumberdaya Hayati 1, Nr. 2 (04.05.2016): 60–63. http://dx.doi.org/10.29244/jsdh.1.2.60-63.
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Environmental factors greatly influence the physiological state of moss. Some of the environmental factors that influence the physiological of moss are air temperature, humidity, and light intensity. These three environmental factors will vary at each altitude. This study aims to determine the physiological characteristics of mosses on some altitudes in the area of Mount Tangkuban Perahu (Ratu Crater – Domas Crater track). The method that are used is to measure air temperature, humidity, and light intensity at some altitudes. Subsequently, samples were taken at each altitude, to measured chlorophyll and proline content. Mosses that are used as samples; Campylopus sp., Plagiochila sp., Dicranella sp. The results indicate that the chlorophyll content significantly different at some altitude, with an increasing trend as the decrease altitude. The highest chlorophyll content in Campylopus sp. at altitude of 1,621 meters above sea level, while the lowest chlorophyll content in Plagiochila sp. at altitude of 1,721 meters above sea level. The content of proline did not differ significantly at some altitude, and tend to be more affected by air conditions that correlate with distance of moss habitat with the active crater of Domas, which allegedly can cause physiological stress in the moss.
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Spring, Allison M., Kenneth D. Domingue, Thomas V. Kerber, Margaret M. Mooney, Rebecca L. Hale, Kristina M. Lemmer und Kathryn M. Docherty. „Land Use Effects on Airborne Bacterial Communities Are Evident in Both Near-Surface and Higher-Altitude Air“. Diversity 13, Nr. 2 (18.02.2021): 85. http://dx.doi.org/10.3390/d13020085.
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Land use influences the composition of near-surface airborne bacterial communities, and bacteria can be transported through the atmosphere at global scales. The atmosphere mixes vertically, but rigorously assessing whether the effects of land use on atmospheric communities extends to higher altitudes requires examining communities from multiple altitudes collected at a stable location and timeframe. In this study, we collected near-surface (<2 m) and higher-altitude (150 m) air samples from three sites in an agricultural/developed location and a forested/undeveloped location. We used bacterial 16S rRNA amplicon sequencing to compare communities and predict functionality by altitude. Higher-altitude and near-surface communities did not differ in composition within each location. Communities collected above the undeveloped location were equally variable at both altitudes; higher-altitude samples from the developed location predominantly contained Firmicutes and were less variable than near-surface samples. We also compared airborne taxa to those present in soil and snow. Communities from higher-altitude samples above the developed location contained fewer overlapping taxa with soil and snow sources, and overlapping Operational Taxonomic Units (OTUs) among the three sources differed by location. Our results suggest that land use affects the composition of both near-surface and higher-altitude airborne bacterial communities and, therefore, may influence broad bacterial dispersal patterns. This small-scale pilot study provides a framework for simultaneously examining local and regional airborne microbial communities that can be applied to larger studies or studies using different types of samplers.
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Lei, Tian, Jinliang Xu, Xingli Jia, Leyu Wei und Lin Tian. „Impact of High-Altitude on Truck’s Climbing Speed: Case study in Qinghai-Tibet Plateau Area in China“. Journal of Advanced Transportation 2019 (20.08.2019): 1–14. http://dx.doi.org/10.1155/2019/8560204.
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Truck’s climbing performance is an important consideration in traffic safety, efficiency, and highway geometric design. With the infrastructure development in high-altitude area in China, more attention needs to be paid on truck’s climbing performance in such area. In this article, truck’s climbing speed in high-altitude area was examined through field tests on different grade sections at different altitudes. Truck’s speed-distance curves were built at different altitudes and the impact of altitude on truck’s climbing speed was explored based on the test results. It was shown that, within the altitude range of 3000~5000m, altitude had an obvious influence on test truck’s decelerating and accelerating performance. Truck’s speed decreased faster on steep grades and increased slower on gentle grades with the increase of the altitude. Also, the stable speed that test truck could maintain on a certain grade was lower at a higher altitude. In addition, test truck’s theoretical speed-distance curves at the sea level were estimated through truck’s dynamic model. Compared with the theoretical crawl speed, a negative effect of altitude change (from 0 to the altitude above 3000 m) was found on truck’s climbing performance.
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Hovenden, Mark J., und Tim Brodribb. „Altitude of origin influences stomatal conductance and therefore maximum assimilation rate in Southern Beech, Nothofagus cunninghamii“. Functional Plant Biology 27, Nr. 5 (2000): 451. http://dx.doi.org/10.1071/pp99164.
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Gas exchange measurements were made on saplings of Southern Beech, Nothofagus cunninghamii (Hook.) Oerst. collected from three altitudes (350, 780 and 1100 m above sea level) and grown in a common glasshouse trial. Plants were grown from cuttings taken 2 years earlier from a number of plants at each altitude in Mt Field National Park, Tasmania. Stomatal density increased with increasing altitude of origin, and stomatal con-ductance and carbon assimilation rate were linearly related across all samples. The altitude of origin influenced thestomatal conductance and therefore carbon assimilation rate, with plants from 780 m having a greater photosynthetic rate than those from 350 m. The intercellular concentration of CO2 as a ratio of external CO2 concentration (ci/ca) was similar in all plants despite the large variation in maximum stomatal conductance. Carboxylation efficiency was greater in plants from 780 m than in plants from 350 m. Altitude of origin has a strong influence on the photo-synthetic performance of N. cunninghamii plants even when grown under controlled conditions, and this influence is expressed in both leaf biochemistry (carboxylation efficiency) and leaf morphology (stomatal density).
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Tu, Ran, Yi Zeng, Jun Fang und Yong-Ming Zhang. „Influence of high altitude on the burning behaviour of typical combustibles and the related responses of smoke detectors in compartments“. Royal Society Open Science 5, Nr. 4 (April 2018): 180188. http://dx.doi.org/10.1098/rsos.180188.
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The effect of altitude on typical combustible burning and related smoke detector response signals was investigated by comparison experiments at altitudes of 40 m and 3650 m based on EN54 standard tests. Point-type light scattering photoelectric smoke detectors and ionization smoke detectors were used for four kinds of EN54 fire tests, including two kinds of smouldering fires with wood (test fire no. 2 in EN54 standard or TF2) and cotton (TF3), and two kinds of flaming fires with polyurethane (TF4) and n -heptane (TF5). First, the influence of altitude or ambient pressure on mass loss for smouldering combustion (TF2 or TF3) was insignificant, while a significant decrease in the mass burning rate was found for flaming tests (TF4 and TF5) as reported in our previous studies. Second, for photoelectric smoke detectors in flaming fire tests, the effect of altitude was similar to that of the burning rate, whereas for the ionization smoke detectors, the response signal at high altitudes was shown to be ‘enhanced’ by the detection principle of the ionization chamber, leading to an even larger value than at normal altitude for smouldering conditions. Third, to provide a reference for smoke detector design in high-altitude areas, the differences between signal speed in rising and peak values at two locations are discussed. Also, relationship between ion chamber signals and smoke optical densities are presented by utilization of an ionization smoke detector and smoke concentration meter. Moreover, a hierarchical diagram is illustrated to provide a better understanding of the effects of altitude on combustible burning behaviour and the mechanisms of detector response.
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Wang, Shuling, Zhe Shao und Jie Li. „THE INFLUENCE OF VARIATION IN ALTITUDE ON ATHLETIC PERFORMANCE IN LONG-DISTANCE RUNNERS“. Revista Brasileira de Medicina do Esporte 28, Nr. 5 (Oktober 2022): 584–86. http://dx.doi.org/10.1590/1517-8692202228052022_0101.
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ABSTRACT Introduction: The academic community has demonstrated the link of athletic performance in track and field with critical factors of sports training, including the psychology of competition. Recently, research has been verified that athletic performance is also related to altitude, weather, ambiance, and the timing of the competition. There are no studies to provide theoretical and practical training experience in the regional environment of Ganzhou. Objective: This paper analyzes the influence of altitude training in professional performance athletes. Concurrently, analysis of the physiological and biochemical indicators of the athletes is performed. Methods: Several long-distance runners had an 8-week altitude training. Analyzed the physiological and biochemical indicators of the athletes before and after the training. At the same time, perform mathematical-statistical analysis on the performance of long-distance runners before and after training. Results: After altitude training, hemoglobin and red blood cells showed a significant decrease (P<0.01). After training, athletes’ performance improved considerably (P<0.01). Conclusion: Training at different altitudes may promote an ascending curve in the athletes’ performance until a plateau in the fourth week of training. Evidence Level II; Therapeutic Studies - Investigating the result.
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Carvalho, Biange Maria Cezário de, Raquel Leite Wainfas, Tayanna Rodrigues, Lidiane Coelho Berbert, Thaiane Franklin, Ivyn Karla Lima de Sousa und Ronaldo Figueiró. „Black fly (Diptera:Simuliidae) larvae body size variation along an altitude gradient in the Itatiaia National Park, Brazil“. Revista Acta Ambiental Catarinense 13, Nr. 1 (24.08.2016): 1. http://dx.doi.org/10.24021/raac.v13i1.3314.
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According to Bergmann’s Rule, individuals who inhabit higher altitudes tend to be larger in body mass or size, when compared with individuals of the same taxon who inhabit lower altitude places. Black flies are insects of great medical and veterinary importance due to its blood-sucking habit, becoming subject of studies regarding its bionomics, ecology and taxonomy. Studies approaching the influence of the altitude gradient in the morphology of Diptera: Simuliidae larvae are scarce in the literature, therefore, this study aimed to investigate the influence of altitude gradient in the morphology of Diptera: Simullidae larvae in Itatiaia National Park, RJ, and thus verify if Bergmann’s Rule is applicable to these organisms. Black fly larvae were sampled from four sites during periods of March and May 2013. From each site 30 larvae were measured, and these lengths were later compared between sites using Kruskal-Wallis, which showed a significant difference (P<.05) among sites from lower altitudes in relation to those of higher elevations, what was corroborated using a cluster analysis. The altitude was related to larval size using a linear regression, showing a positive correlation between these variables, thus corroborating Bergmann’s rule for Black flies.
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Yang, Xue, Long Di Cheng, Li Qian Huang und Wen Hong Fan. „Study on the Correlation between the Property of Akund Fiber and its Growing Conditions“. Advanced Materials Research 476-478 (Februar 2012): 1934–38. http://dx.doi.org/10.4028/www.scientific.net/amr.476-478.1934.
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In this paper ,the properties of akund fiber, growing at the altitudes of 813m, 1080m and 1153m from August to October were studied, respectively.The influences of altitude, month, fruit size and different parts of the fruit on the properties of akund fiber were also analyzed. It was found that the altitude and fruit size had a significant correlation coefficient with the property of akund fiber, while the influence of month on the property of akund fiber was not obvious. The properties of the fiber in different parts of the fruit were also different.The results will be beneficial to planting, harvesting, processing and exploiting this fiber.
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Ferreira, Anna Carolyna Fernandes, Felipe Vaz Andrade, Eduardo de Sá Mendonça und Paulo Roberto da Rocha Júnior. „Land use and altitude: how do they influence the phosphorus fractions?“ Acta Scientiarum. Agronomy 44 (24.05.2022): e54801. http://dx.doi.org/10.4025/actasciagron.v44i1.54801.
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Soil use and management systems modify phosphorus (P) dynamics by changing the different P compartments. However, the interaction between land-use change and altitude is not clear. This study aimed to evaluate the effect of land use on P forms in different soil aggregate classes of Ultisols located at two altitudes. Soil samples were collected in four land-use systems (agroforestry system, secondary forest, pasture, and eucalyptus) located at two altitudes in the Atlantic Forest biome, Brazil. Phosphorus fractions were assessed using sequential fractionation. In general, recalcitrant forms represented about 70% in the agroforestry system, 66% in the eucalyptus, 65% in the pasture, and 57% in the secondary forest relative to the total P content of all land uses at both altitudes. The soil aggregate classes of smaller diameter presented higher P contents in all fractions. The smallest soil aggregate classes showed up to 65% more P than the classes with smaller diameters in the different land-use systems and altitudes.
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Hevko, Bohdan, und Jurii Bondar. „Influence of flight mode on loads from turbulent air“. MECHANICS OF GYROSCOPIC SYSTEMS, Nr. 42 (28.12.2022): 117–27. http://dx.doi.org/10.20535/0203-3771422021268893.
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This paper investigated the influence of altitude and flight speed on the loads arising on the elastic wing of a turbojet aircraft of conventional layout, which falls into turbulent conditions. The aircraft structure is modeled by elastic beams with appropriate weight and stiffness distribution. Performed a modal analysis of the aircraft design and examined the influence of the number of calculated tones own oscillations on the loading of an aircraft wing. Aerodynamic forces and moments are determined by the dipole lattice and constant pressure method (DLM/CPM). Non-stationary characteristics are also taken into account, as required by certification specification. Determining the effect of flight speed showed the need to consider both the minimum and maximum speeds, because at minimum speed the end zone of the wing is loaded more, and at the cruise speed ‒ the root section. When analyzing the effect of flight altitude on the load, determined that the maximum values of transverse force and bending moment occur when flying at minimum altitude, and the torque on the wing reaches the maximum value at altitudes with the maximum Mach number. Separately highlighted loads of aircraft wing at horizontal balanced flight. Also showed that the speed of flight, namely the Mach number, significantly affects the torque that occurs on the wing.
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Li, Qi, Mingyang Chen, Wenjing Xie, Qianyue Wang, Yue Wu, Chang Yang und Jiangming Zhen. „Study on Energy-saving Lighting Design Method for Interior Zone of High-altitude Highway Tunnel“. E3S Web of Conferences 189 (2020): 03035. http://dx.doi.org/10.1051/e3sconf/202018903035.
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In order to ensure the driving safety of high-altitude highway tunnel and effectively reduce the lighting cost, this paper adopts the method considering the influence of automobile headlights luminance which combines reaction time incremental theory at different altitudes and lighting design simulation calculation. The paper has studied the design pattern of high-altitude highway tunnel, which are dominated by fixed lighting and supplemented by automotive lighting. The results show that: to ensure driving safety, the luminance of the lighting design for interior zone of highway tunnel increases with the increasing altitude. Based on the supplementary lighting of automobile headlights, the lighting design standards for the interior zone of high-altitude highway tunnel(the altitude is 2000m, 3000m, 4000m, 5000m respectively) are 0.73cd/m2, 0.82cd/m2, 0.91cd/m2, 1.0cd/m2.
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Höffner, J., und J. S. Friedman. „Metal layers at high altitudes: A possible connection to meteoroids“. Atmospheric Chemistry and Physics Discussions 4, Nr. 1 (20.01.2004): 399–417. http://dx.doi.org/10.5194/acpd-4-399-2004.
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Abstract. In the past, many studies have been carried out to demonstrate the influence of meteoroids on the atmospheric metal layer, observed roughly in the altitude range 80–105 km. Even with the capability of present day resonance lidars to measure metal densities within single meteor trails, it has been difficult to prove any influence of meteors on the average metal layer. In contrast to approaches taken earlier, we discuss here the seasonal characteristics of potassium, calcium, calcium ion, iron and sodium above 110 km altitude where the average nocturnal densities are so low that the existence of a baseline level of metal atoms and ions is often overlooked. By comparing simultaneous and common-volume observations of different metal layers at one location, we demonstrate that despite their different seasonal characteristics at lower altitudes remarkably similar seasonal characteristics are observed at higher altitudes. In addition, for potassium at different latitudes a qualitative agreement is also found. A comparison of metal densities at 113 km altitude with known meteor showers indicates a strong influence of shower meteoroids on the topside of the metal layers. Simultaneous observations of K along with Ca, Fe and/or Na permits the calculation of abundance ratios. We find that these ratios at 113 km altitude are quite similar to values measured in single meteor trails by ground based lidars. Given these evidences, we contend that there is a direct influence of ablating meteoroids on the topside of the mesospheric metal layer. Furthermore, the increase in densities throughout summer with similar abundance ratios as observed during meteor showers is a strong evidence for the influence of sporadic meteoroids on the high metal layers.
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Höffner, J., und J. S. Friedman. „The mesospheric metal layer topside: a possible connection to meteoroids“. Atmospheric Chemistry and Physics 4, Nr. 3 (26.05.2004): 801–8. http://dx.doi.org/10.5194/acp-4-801-2004.
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Abstract. In the past, many studies have been carried out to demonstrate the influence of meteoroids on the atmospheric metal layer, observed roughly in the altitude range 80–105 km. Even with the capability of present day resonance lidars to measure metal densities within single meteor trails, it has been difficult to prove any influence of meteors on the average metal layer. In contrast to approaches taken earlier, we discuss here the seasonal characteristics of potassium, calcium, calcium ion, iron and sodium above 110 km altitude where the average nocturnal densities are so low that the existence of a baseline level of metal atoms and ions is often overlooked. By comparing simultaneous and common-volume observations of different metal layers at one location, we demonstrate that despite their different seasonal characteristics at lower altitudes remarkably similar seasonal characteristics are observed at higher altitudes. In addition, a qualitative agreement is also found for potassium at different latitudes. A comparison of metal densities at 113 km altitude with known meteor showers indicates a strong influence of shower meteoroids on the topside of the metal layers. Simultaneous observations of K along with Ca, Fe and/or Na permit the calculation of abundance ratios, which at 113 km altitude are quite similar to values measured in single meteor trails by ground based lidars. Furthermore, the increase in densities throughout summer is strong evidence for the influence of sporadic meteoroids on the high metal layers. This increase correlates well with the seasonal variation of sporadic micrometeor input independent of meteor showers. Given these evidences, we contend that there is a direct influence of ablating meteoroids on the topside of the mesospheric metal layer.
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Girma, Bealu, Abera Gure und Feyisa Wedajo. „Influence of Altitude on Caffeine, 5-Caffeoylquinic Acid, and Nicotinic Acid Contents of Arabica Coffee Varieties“. Journal of Chemistry 2020 (12.08.2020): 1–7. http://dx.doi.org/10.1155/2020/3904761.
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The influence of altitude on caffeine, 5-caffeoylquinic acid (5-CQA), and nicotinic acid contents of Arabica coffee varieties grown in Southwest Ethiopia was investigated. High-performance liquid chromatography with diode array detector (HPLC-DAD) was used for the determination of the target analytes. Coffee samples were collected from four coffee varieties, named as 74112, 7454, 7440, and 74110, which are cultivated in high, mid, and low altitudes in the study area. The findings of the study showed that the contents of caffeine and 5-CQA in both raw and roasted coffee beans decrease as the growing altitude increases and, thus, for all varieties, their highest concentrations were recorded in lowland coffee beans. Nevertheless, the contents of nicotinic acid increase as the altitude rises and, thus, the highest nicotinic acid content was recorded in highland coffee samples. Besides, after roasting, the contents of caffeine were increased, whereas the contents of 5-CQA were lowered, indicating the possibility of its degradation during the roasting process. Both green and roasted coffee beans also contained relatively higher concentrations of nicotinic acids. Other than the growing altitudes, the contents of caffeine, 5-CQA, and nicotinic acid in coffee beans also vary with coffee varieties. Therefore, coffee varieties that are cultivated at various altitudes may have different biochemical compositions such as caffeine, CGAs, and nicotinic acid that could greatly influence the flavor, aroma, and stimulating attributes of coffee cup quality as well as dietary benefits.
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Roșian, Gheorghe, Csaba Horvath, Liviu Muntean und Nicolae Baciu. „The Influence of Landform in the Distribution of Households of Ilva Mică Territorial Administrative Unit“. Studia Universitatis Babeș-Bolyai Ambientum 66, Nr. 1-2 (30.11.2022): 53–62. http://dx.doi.org/10.24193/subbambientum.2021.05.
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"In the case of territorial administrative units located in hilly and mountainous lands, landform, through its morphometric parameters, is a variable that introduces significant differences in the distribution of households. A similar situation is the case of the Ilva Mică commune, where, due to its position at the border between the Eastern Carpathians and the Transylvanian Basin, the landform is extremely varied. Among the parameters of the landform taken into consideration for tracking the distribution of households, the following parameters stand out: altitude, slope and slope aspect. The results show that as the development of Ilva Mică took place, favorable lands were used for building households along with less favorable areas located at altitudes higher than the average altitude of the commune (704 m) and with slopes higher than 17°. This occurred both because of lack of space and of economic reasons, such as the land use for livestock. Keywords: altitude, slope, aspect, household, distribution. "
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Sangeetha, Thangavelu, Tajuddin Nargis Begum, Balasubramanian Balamuralikrishnan, Meyyazhagan Arun, Kannan R. R. Rengasamy, Natchiappan Senthilkumar, Shanmugam Velayuthaprabhu, Muthukrishnan Saradhadevi, Palanisamy Sampathkumar und Arumugam Vijaya Anand. „Influence of SERPINA1 Gene Polymorphisms on Anemia and Chronic Obstructive Pulmonary Disease“. Journal of the Renin-Angiotensin-Aldosterone System 2022 (17.10.2022): 1–8. http://dx.doi.org/10.1155/2022/2238320.
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Background. Anemia is one of the predominant hematological conditions, whereas chronic obstructive pulmonary disease (COPD) is a predominant respiratory disease. These two diseases were found to be interlinked, but the physiological pathways are still unclear. Aim. The current study has been aimed at analysing the genetic interrelationship between anemia and COPD in accordance with different altitudes. Methodology. The genetic analysis was performed in the SERPINA1 gene of anemia, COPD, and healthy individuals for the analysis of single nucleotide polymorphism at rs28949274 and rs17580 locations. Result and Discussion. The single nucleotide polymorphism at the locations rs28949274 and rs17580 was present in both anemic and COPD patients. The COPD patients were more prone to mutations (63% had rs28949274, and 11% had rs17580 polymorphisms) than the anemic patients (40% had rs28949274, and 1% had rs17580 polymorphisms). On the basis of altitude, high-altitude individuals were found to be more susceptible to both the polymorphisms. Conclusion. Based on the current findings, we suggest that the SERPINA1 gene has a positive correlation with anemia as well as COPD, and the increase in altitude also influences the diseased conditions in a positive manner.
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Swayze, Neal C., Wade T. Tinkham, Matthew B. Creasy, Jody C. Vogeler, Chad M. Hoffman und Andrew T. Hudak. „Influence of UAS Flight Altitude and Speed on Aboveground Biomass Prediction“. Remote Sensing 14, Nr. 9 (21.04.2022): 1989. http://dx.doi.org/10.3390/rs14091989.
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The management of low-density savannah and woodland forests for carbon storage presents a mechanism to offset the expense of ecologically informed forest management strategies. However, existing carbon monitoring systems draw on vast amounts of either field observations or aerial light detection and ranging (LiDAR) collections, making them financially prohibitive in low productivity systems where forest management focuses on promoting resilience to disturbance and multiple uses. This study evaluates how UAS altitude and flight speed influence area-based aboveground forest biomass model predictions. The imagery was acquired across a range of UAS altitudes and flight speeds that influence the efficiency of data collection. Data were processed using common structures from motion photogrammetry algorithms and then modeled using Random Forest. These results are compared to LiDAR observations collected from fixed-wing manned aircraft and modeled using the same routine. Results show a strong positive relationship between flight altitude and plot-based aboveground biomass modeling accuracy. UAS predictions increasingly outperformed (2–24% increased variance explained) commercial airborne LiDAR strategies as acquisition altitude increased from 80–120 m. The reduced cost of UAS data collection and processing and improved biomass modeling accuracy over airborne LiDAR approaches could make carbon monitoring viable in low productivity forest systems.
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Chen, Yongming, Zehua Chang, Shiguo Xu, Peng Qi, Xiaoyu Tang, Yang Song und Dongmei Liu. „Altitudinal Gradient Characteristics of Spatial and Temporal Variations of Snowpack in the Changbai Mountain and Their Response to Climate Change“. Water 13, Nr. 24 (14.12.2021): 3580. http://dx.doi.org/10.3390/w13243580.
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The variations in the snowpack in water towers of the world due to climate change have threatened the amount and timing of freshwater supplied downstream. However, it remains to be further investigated whether snowpack variation in water towers exhibits elevational heterogeneity at different altitude gradients and which climatic factors mainly influence these differences. Therefore, Changbai Mountain, a high-latitude water tower, was selected to analyze the changes in the snowpack by the methods of modified Mann–Kendall based on the daily meteorological data from the China Meteorological Data Service Centre. Meanwhile, the responses of snowpack change to climatic factors over recent decades were assessed and generalized using additive models. The results showed that the snow depth was greater in the higher altitude areas than in the lower elevation areas at different times. Areas with a snow depth of over 70 mm increased significantly in the 2010s. Increasing trends were shown at different altitudes from December to March of the next year during 1960~2018. However, a significant decreasing trend was shown in April, except for altitudes of 600–2378 m. The snow cover time at different altitudes showed a trend of first increasing and then decreasing during 1960~2018. The date of maximum snow depth appears to be more lagged as the altitude increases. In addition, the spring snowpack melted significantly faster in the 2010s than that in the 1960s. The snowpack variation in low-altitude regions is mainly influenced by ET and relative humidity. However, the mean temperature gradually became an important factor, affecting the snow depth variation with the increase in altitude. Therefore, the results of this study will be beneficial to the ecological protection and sustainable development of water towers.
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Cook, James D., Erick Boy, Carol Flowers und Maria del Carmen Daroca. „The influence of high-altitude living on body iron“. Blood 106, Nr. 4 (15.08.2005): 1441–46. http://dx.doi.org/10.1182/blood-2004-12-4782.
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Abstract The quantitative assessment of body iron based on measurements of the serum ferritin and transferrin receptor was used to examine iron status in 800 Bolivian mothers and one of their children younger than 5 years. The survey included populations living at altitudes between 156 to 3750 m. Body iron stores in the mothers averaged 3.88 ± 4.31 mg/kg (mean ± 1 SD) and 1.72 ± 4.53 mg/kg in children. No consistent effect of altitude on body iron was detected in children but body iron stores of 2.77 ± 0.70 mg/kg (mean ± 2 standard error [SE]) in women living above 3000 m was reduced by one-third compared with women living at lower altitudes (P < .001). One half of the children younger than 2 years were iron deficient, but iron stores then increased linearly to approach values in their mothers by 4 years of age. When body iron in mothers was compared with that of their children, a striking correlation was observed over the entire spectrum of maternal iron status (r = 0.61, P < .001). This finding could provide the strongest evidence to date of the importance of dietary iron as a determinant of iron status in vulnerable segments of a population. (Blood. 2005;106:1441-1446)
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Malfatti, Eduardo, Pedro M. A. Ferreira und Laura R. P. Utz. „Eukaryotic Communities in Bromeliad Phytotelmata: How Do They Respond to Altitudinal Differences?“ Diversity 12, Nr. 9 (28.08.2020): 326. http://dx.doi.org/10.3390/d12090326.
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Bromeliad phytotelmata are habitats for different organisms and models for ecological studies. Although poorly known, these environments are widely distributed in tropical ecosystems, harboring cosmopolitan and endemic species. Here, we investigated the diversity of the eukaryotic community in bromeliad phytotelmata considering the influence of altitude. We randomly sampled three bromeliad individuals (twice per season over one year) at four altitudinal strata (20 m, 400 m, 910 m, and 915 m) through a mountain range in southern Brazil. Species richness of phytotelmata community was higher at intermediate altitude while community-wide multivariate analyses revealed differences in phytotelmata communities at each height. Winter was the season with highest community richness, but a peak in summer was observed. Diversity partitioning in different spatial components showed that gamma diversity decreased linearly with altitude, whereas alpha diversity peaked at intermediate altitudes, and beta diversity decreased with height. The relative importance of the components of beta diversity showed different patterns according to the altitude: turnover was more important at intermediate and lower levels, while higher altitude communities were more nested. Our results indicate that differences in height affect diversity patterns of bromeliad phytotelmata communities, which were more diverse at lower altitudes in comparison with more homogeneous communities at higher levels.
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Franzén, Markus, und Petra Dieker. „The influence of terrain age and altitude on the arthropod communities found on recently deglaciated terrain“. Current Zoology 60, Nr. 2 (01.04.2014): 203–20. http://dx.doi.org/10.1093/czoolo/60.2.203.
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Abstract Climate warming has been more pronounced in the Arctic than elsewhere, resulting in a recent rapid glacial retreat. Over 85% of the Ålmajallojekna glacier has disappeared over the last 115 years and it is one of the fastest retreating glaciers in Sweden. In 2011 and 2012, at 18 sites in the vicinity of the remaining glacier network, we sampled arthropods and related the species richness, abundance and proportion of herbivores to altitude (ranging from 824 to 1, 524 m.a.s.l.) and the age of the site (ranging from 0 to >115 years). Temperature was measured at six sites and the average annual air temperature ranged from -3.7°C to 1.1°C. In total, we recorded 3, 705 arthropods from 117 species in nine different taxonomic groups. The most abundant and species-rich group was Coleoptera (1, 381 individuals, 41 species) followed by Araneae (1, 050 individuals, 15 species) and Mac-rolepidoptera (732 individuals, 17 species). Only at lower altitudes did the abundance and species richness of arthropods increase with increasing age of the site. The results were consistent among the studied taxonomic groups and when controlling for sampling intensity using two different approaches. The proportion of herbivores decreased with increasing age of the site and with increasing altitude. Clearly, altitude appears more important than the age of the site and, at higher altitudes, abundance, species richness and herbivory are low.
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Bateman, Brooke L., Alex S. Kutt, Eric P. Vanderduys und Jeanette E. Kemp. „Small-mammal species richness and abundance along a tropical altitudinal gradient: an Australian example“. Journal of Tropical Ecology 26, Nr. 2 (29.01.2010): 139–49. http://dx.doi.org/10.1017/s0266467409990460.
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Abstract:This study examined patterns in the species richness and abundance of small non-volant mammals along a tropical altitudinal gradient in north-eastern Australia. We investigated whether a mid-altitudinal peak in diversity was apparent, and if it occurred, whether it was determined by particular environmental conditions. We sampled a small-mammal assemblage at 17 sites distributed along an altitude-environmental gradient from savanna (350 m) to rain-forest vegetation (1000 m). Over four separate occasions (5100 trap-nights) we recorded 17 species of mammal with 416 captures. A positive non-linear relationship between altitude and mammal species richness and abundance was observed, peaking at the 800–900 m range. Many species were distributed across a range of altitudes, while others were strongly associated with particular habitat conditions. There was a distinct reduction in abundance and species richness at low altitudes associated with the less complex vegetation, lower productivity and possible anthropogenic effects. Key findings were: that small-mammal richness peaked towards the summit of the gradient and not at one-half the maximum altitude predicted by the mid-domain effect; contrasting conditions and greatest vegetation juxtaposition had the greatest influence on the patterns recorded; and that local idiosyncratic influences such as habitat factors, land management and historical biogeography are significant.
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Seifert, Erich, Stefan Seifert, Holger Vogt, David Drew, Jan van Aardt, Anton Kunneke und Thomas Seifert. „Influence of Drone Altitude, Image Overlap, and Optical Sensor Resolution on Multi-View Reconstruction of Forest Images“. Remote Sensing 11, Nr. 10 (27.05.2019): 1252. http://dx.doi.org/10.3390/rs11101252.
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Recent technical advances in drones make them increasingly relevant and important tools for forest measurements. However, information on how to optimally set flight parameters and choose sensor resolution is lagging behind the technical developments. Our study aims to address this gap, exploring the effects of drone flight parameters (altitude, image overlap, and sensor resolution) on image reconstruction and successful 3D point extraction. This study was conducted using video footage obtained from flights at several altitudes, sampled for images at varying frequencies to obtain forward overlap ratios ranging between 91 and 99%. Artificial reduction of image resolution was used to simulate sensor resolutions between 0.3 and 8.3 Megapixels (Mpx). The resulting data matrix was analysed using commercial multi-view reconstruction (MVG) software to understand the effects of drone variables on (1) reconstruction detail and precision, (2) flight times of the drone, and (3) reconstruction times during data processing. The correlations between variables were statistically analysed with a multivariate generalised additive model (GAM), based on a tensor spline smoother to construct response surfaces. Flight time was linearly related to altitude, while processing time was mainly influenced by altitude and forward overlap, which in turn changed the number of images processed. Low flight altitudes yielded the highest reconstruction details and best precision, particularly in combination with high image overlaps. Interestingly, this effect was nonlinear and not directly related to increased sensor resolution at higher altitudes. We suggest that image geometry and high image frequency enable the MVG algorithm to identify more points on the silhouettes of tree crowns. Our results are some of the first estimates of reasonable value ranges for flight parameter selection for forestry applications.
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Saha, Sushil, Govind-Singh Rajwar und Munesh Kumar. „Forest structure, diversity and regeneration potential along altitudinal gradient in Dhanaulti of Garhwal Himalaya“. Forest Systems 25, Nr. 2 (20.07.2016): e058. http://dx.doi.org/10.5424/fs/2016252-07432.
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Aim of the study: The aim of the present study was to understatnd the forest composition, structure, diversity and regeneration potential along altitudinal gradient.Area of study: The study was carried out in Dhanaulti forest which falls under temperate region of Garhwal Himalaya in Uttarakhand state, India.Material and Methods: Vegetation analysis was carried out using 10 quadrats at each altitude using a quadrate size of 10×10 m2. In each quadrate, categories of trees >30 cm cbh were considered as trees, 10-30cm cbh as saplings and <10 cm cbh as seedlings. The data were quantitatively analyzed.Main results: In upper and middle altitudes, Cedrus deodara was reported dominant tree whereas, in lower altitude Quercus leucotrichophora was reported dominant. Tree density was highest in lower altitude which reduced middle and upper altitudes whereas, total basal cover increased with increasing altitude. The increasing total basal cover with altitude could be because of the presence of Cedrus deodara trees having higher girth classes. In tree, sapling and seedling layers, diversity (H) and equitabiltiy (EC) decreased with increasing altitude. However, concentrations of dominace (CD) and beta diversity (BD have shown reverse trend with H and EC which increased with increasing altitudes, in each layer of tree, sapling and seedling.The distribution pattern of most species in all layers of trees, saplings and seedlings was contagious. The regeneration potential of the species has shown that some of the species in the absence of tree layer are still regenerating particularly, Rhododendron arboreum, Benthamidia capitata, Neolitsea pallens etc. It indicates that most of the species are shifting upward as they are getting suitable conditions.Research highlights: Altitude influence species composition, diversity and regeneration potential of species.Key words: Distribution pattern; tree diversity; regeneration; mountains; temperate; Himalaya.
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Lunghi, Alex, Franck Brocherie und Grégoire P. Millet. „Influence of Altitude on Elite Biathlon Performances“. High Altitude Medicine & Biology 20, Nr. 3 (01.09.2019): 312–17. http://dx.doi.org/10.1089/ham.2019.0008.
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Gourgoulianis, Konstantinos I., Nicolaos Brelas, Gregorios Hatziparasides, Marı́a Papayianni und Paschalis-Adams Molyvdas. „The Influence of Altitude in Bronchial Asthma“. Archives of Medical Research 32, Nr. 5 (September 2001): 429–31. http://dx.doi.org/10.1016/s0188-4409(01)00302-2.
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Dotdaeva, A. A., Kh A. Kurdanov und S. A. Boytsov. „MORBIDITY AND MORTALITY FROM CARDIOVASCULAR DISEASES ACCORDING TO THE SEA-LEVEL RELATED ALTITUDE OF A REGION“. Cardiovascular Therapy and Prevention 13, Nr. 6 (28.12.2014): 51–55. http://dx.doi.org/10.15829/1728-8800-2014-6-51-55.
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It is known that the common risk factors (RF) of cardiovascular diseases (CVD) do exist and do influence all people the same. Among them are arterial hypertension, smoking, total cholesterol, obesity etc. However there are specifics of RF realization connected to climatogeographic specifics, i.e. high mountain altitudes. The review is concerned on the influence of the high altitude influence on RF of CVD. Some papers show that in high altitudes inhabitants the RF of CVD were prognostically malevolent, but the level of total and coronary mortality was lower in mountain inhabitants that can be explained by more intensive physical exertion with the background moderate hypoxia. There is an opinion that lower mortality in higher altitudes can be explained as connected with physiological adaptation to altitude and/or specifics of the climate (i.e. with UV-rays exposure, those become more intensive by 10% every 300 m). Lipidogramm are supposedly linked to moderate hypoxia and lowering of temperature, also the diet specifics might influence. However there is no stabile relation of mortality and the parameters studied. So the results collected in different trials are still controversial. But if long-term living in higher altitudes, secondarily, by the activation of adaptation capacities of the body, diet specifics and physical exertion, leads to the decrease of morbidity and mortality from CVD, short-term visiting of the mountains might be harmful for some persons and this requires individualized approach to recommendations of prevention.
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White, D. P., K. Gleeson, C. K. Pickett, A. M. Rannels, A. Cymerman und J. V. Weil. „Altitude acclimatization: influence on periodic breathing and chemoresponsiveness during sleep“. Journal of Applied Physiology 63, Nr. 1 (01.07.1987): 401–12. http://dx.doi.org/10.1152/jappl.1987.63.1.401.
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Although the influence of altitude acclimatization on respiration has been carefully studied, the associated changes in hypoxic and hypercapnic ventilatory responses are the subject of controversy with neither response being previously evaluated during sleep at altitude. Therefore, six healthy males were studied at sea level and on nights 1, 4, and 7 after arrival at altitude (14,110 ft). During wakefulness, ventilation and the ventilatory responses to hypoxia and hypercapnia were determined on each occasion. During both non-rapid-eye-movement and rapid-eye-movement sleep, ventilation, ventilatory pattern, and the hypercapnic ventilatory response (measured at ambient arterial O2 saturation) were determined. There were four primary observations from this study: 1) the hypoxic ventilatory response, although similar to sea level values on arrival at altitude, increased steadily with acclimatization up to 7 days; 2) the slope of the hypercapnic ventilatory response increased on initial exposure to a hypoxic environment (altitude) but did not increase further with acclimatization, although the position of this response shifted steadily to the left (lower PCO2 values); 3) the sleep-induced decrements in both ventilation and hypercapnic responsiveness at altitude were equivalent to those observed at sea level with similar acclimatization occurring during wakefulness and sleep; and 4) the quantity of periodic breathing during sleep at altitude was highly variable and tended to occur more frequently in individuals with higher ventilatory responses to both hypoxia and hypercapnia.
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Qin, Pengcheng, Mingnian Wang, Zhanwen Chen, Guanfeng Yan, Tao Yan, Changling Han und Anmin Wang. „Effects of Ambient Pressure on Burning Characteristics of Gasoline: A Pilot Study“. Energies 14, Nr. 15 (30.07.2021): 4627. http://dx.doi.org/10.3390/en14154627.
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A fire can pose a significant threat to a building’s occupants and leads to property damage. The burning characteristics usually determine the severity of the accident. Environments in high-altitude areas feature low oxygen content and ambient pressure, which can influence the burning characteristics of combustibles. In this paper, a series of field experiments were conducted to investigate the burning characteristics of gasoline at different altitudes considering heat release rate (HRR), flame height, and smoke release rate. Results show that the combustion process can be divided into three stages: initial stage, stable stage, and attenuation stage. Lower oxygen content and ambient pressure reduce the HRR; for example, the HRR at an altitude of 4150 m is nearly half at an altitude of 500 m, contributing to a lower smoke release rate. The HRR is proportional to 1.3 power of atmospheric pressure, and a fitting equation was brought out in this paper. Flame height increases with the increase in altitude due to the demand for more oxygen during the combustion process since the oxygen content is low in high-altitude areas.
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Burtscher, Johannes, Gregoire P. Millet und Martin Burtscher. „Does living at moderate altitudes in Austria affect mortality rates of various causes? An ecological study“. BMJ Open 11, Nr. 6 (Juni 2021): e048520. http://dx.doi.org/10.1136/bmjopen-2020-048520.
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ObjectivesThe effects of altitude residence on ageing, longevity and mortality are poorly understood. While adaptations to chronic exposure to altitude may exert beneficial effects on cardiovascular risk factors and some types of cancer, an elevated risk to die from chronic respiratory diseases has been reported. Moreover, high-altitude residence may be correlated with increased depression and suicide rates. The present study tested the hypothesis that living at moderate altitudes (up to 2000 m) is associated with reduced mortality from all causes.Setting and participantsWe used a dataset comprising all deaths (n=467 834) across 10 years of a country (Austria) characterised by varying levels of altitudes up to 2000 m.Main outcome measuresTotal number of deaths, age-standardised mortality rates (ASMRs) per 100 000 population, cause-specific ASMRs.ResultsASMRs for residents living in higher (>1000 m) versus lower (<251 m) altitude regions (with agriculture employment below 3%) were 485.8 versus 597.0 (rate ratio and 95% CI 0.81 (0.72 to 0.92); p<0.001) for men and 284.6 versus 365.5 (0.78; 0.66 to 0.91); p=0.002) for women. Higher levels of agriculture employment did not influence mortality rates. Diseases of the circulatory system and cancers were main contributors to lower mortality rates at higher altitude. Residence at higher altitude did not negatively affect mortality rates from any other diseases. We highlight gender effects and—beside environmental factors—also discuss socioeconomic factors that may be responsible for conflicting results with data from other populations.ConclusionsLiving at moderate altitude (1000–2000 m) elicits beneficial effects on all-cause mortality for both sexes, primarily due to lower ASMRs from circulatory diseases and cancer. The presented analysis on cause-specific ASMRs over a 10-year period among the entire population of an alpine country will contribute to a better understanding on the effects of altitude-related mortality.
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Shahbiev, Kh Kh, I. D. Gazaev und A. A. Didanova. „Influence of the vertical zonality of moun-tain ranges of Kabardino-Balkaria on quantitative indicators of sheep infection with bio - and geohelminthes“. International bulletin of Veterinary Medicine 1 (2020): 24–32. http://dx.doi.org/10.17238/issn2072-2419.2020.1.24.
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This article is devoted to the study of susceptibility of sheep to bio - and geohel-minthes at an altitude of 1200 - 3500 m. The sea in the mountain tracts of Kabardino-Balkaria. It is established that in the tracts of Intsyty, Dzhalpak, home, Dougat, located at an altitude of 1200 - 1500 m. the sheep have the same frequency of occurrence. In the tracts of Intsyty, Dzhalpak, home, Dougat, gastrointestinal helminths of 12 species, with the exception of the species T. skrjabi-ni Kalant., 1928, had a high EI level of 47-69%. The tracts Shyki, Bashil, Irikchat, Tyzyl located at an altitude of 1500 - 2000 m.n.u. Sea, sheep folk selection of 5 types of bio - and geohelminthes were found with high incidence (EI = 45-70%); 6 species above the average level of occurrence (EI = 29-38%); 13 species with an average level (EI = 13-24%; 2 species with low levels of reg-istration (EI = 6-12%). Sheep national selection in the tract Irikchat, Tyzyl, Gil-Su, Ush-tulu, Adylsu at an altitude of 2000 - 2500 m, are defined 4 types geohelminthes, they found a higher than average incidence levels (EI = 30-40%); 6 species with an average level of occurrence (ee = 14-26%); 3 species with a weak registration (EI = 7-12%). At an altitude of 2500 - 3000 m in the hole Dykhtau, Zhangugan, Donguz-Orun and Ulla-tau in sheep folk selection highlighted 3 types geohelminthes with an average level of occurrence (EI = 15-27%); 5 species with a weak indicator of EI = 6-11%. The tracts Azau, Cheget, Tau ёzen and Shaurtu at an altitude of 3000 - 3500 m.n.u. Sea, sheep worming national selection was not selected, because at these altitudes, virtu-ally no favorable abiotic conditions for their circadian rhythm.
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Xu, Weitong, Fengyue Zhu, Dengqiang Wang, Daqing Chen, Xinbin Duan, Mingdian Liu und Dapeng Li. „Comparative Analysis of Metabolites between Different Altitude Schizothorax nukiangensis (Cyprinidae, Schizothoracine) on the Qinghai-Tibet Plateau in Nujiang River“. Water 15, Nr. 2 (09.01.2023): 284. http://dx.doi.org/10.3390/w15020284.
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In order to investigate the influence of the high-altitude aquatic environment on indigenous fish metabolites, metabolomics studies were applied in this study. Widespread throughout the main stem of the Nujiang River of Schizothorax nukiangensis, we established sampling sites at high (3890 m) and low (2100 m) altitudes and selected six S. nukiangensis at each location, each weighing approximately 150 g and looking healthy. Then, metabolomics analysis was performed to compare the various metabolites of the two groups. Low concentrations of amino acids, dipeptides, eicosapentaenoic acid, docosahexaenoic acid, pentadecanoic acid, Thioetheramide-PC, 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine, 1-Stearoyl-sn-glycerol-3-phosphocholine, 1-Myristoyl-sn-glycero-3-phosphocholine and 1-Palmitoyl-sn-glycero-3-phosphocholine, high concentrations in S-Methyl-5’-thioadenosine, creatine, D-mannose-6-phosphate, D-mannose-1-phosphate, oleic acid and myristoleic acid were found in high-altitude fish liver. These differentially accumulated metabolites were involved in oxidative stress, energy metabolism, carbohydrate metabolism and lipid metabolism. mTOR signaling pathway, apoptosis and lysosome were the KEGG pathways that were enriched between different groups to ensure energy supply and limit tissue damage of fish at high altitudes. All these results contributed to the understanding of the high-altitude adaptation of S. nukiangensis in the Nujiang River. Nicotine and methoprene, two organic pollutants, performed differently in fish at different altitudes. Overall, our findings advanced the fundamental understanding of fish responses to high-altitude environments, adaptive mechanisms and organic contaminants pollution in the Nujiang River.
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Zhang, Cuixian, Huaifeng Yi, Xianyu Gao, Tianqi Bai, Zhangguang Ni, Yufu Chen, Meicun Wang et al. „Effect of Different Altitudes on Morpho-Physiological Attributes Associated with Mango Quality“. Diversity 14, Nr. 10 (18.10.2022): 876. http://dx.doi.org/10.3390/d14100876.
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Mango (Mangifera indica L.) is a widely cultivated fruit in tropical and subtropical areas at altitudes ranging from 100 to 1500 m above sea level (masl). However, little is known about the effects of altering altitudes on the morpho-physiological traits determining the commercial value of mango. Therefore, we systematically investigated a commercial mango cultivar at eight altitudes ranging from 680 to 1400 masl to check the environmental impact on morpho-physiological attributes and volatile compounds using analysis of variance, principal component analysis, clustering, and correlation. We observed an increase in fruit weight and size from 680 to 1000 masl elevation and a gradual decrease at higher altitudes above 1000 msl. In contrast, quality parameters, including total soluble solids and total sugar, decreased with the increase in altitude, while the total acid increased with the increase in altitude. Moreover, we characterized the dried fruit, pericarp, and sarcocarp for aromatic compounds and identified 110 volatile compounds. The accumulation pattern of the volatiles suggested a considerable influence of environmental factors associated with altering altitudes. However, there was no clear trend in the volatile accumulation at different altitudes. We further determined the ten most frequently occurring volatiles at different altitudes and tissues. For instance, Alpha-Guaiene was only identified at 1000–1215 masl altitudes in dried fruit, while Beta-Ocimene showed the highest accumulation at 900 masl in dried fruit and pericarp. Together, our study provides clues on the impact of the altitude on mango fruit yield and quality attributes, which will guide future agronomic practices.
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Kuster, Vinícius Coelho, Silvana Aparecida Barbosa de Castro und Fernando Henrique Aguiar Vale. „Photosynthetic and anatomical responses of three plant species at two altitudinal levels in the Neotropical savannah“. Australian Journal of Botany 64, Nr. 8 (2016): 696. http://dx.doi.org/10.1071/bt15280.
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The phytophysiognomies of the Neotropical savannah occur at different altitudes, which can determine distinctions in the levels of light and shade that plants are exposed. The focus of the study is analysing the functional traits of the leaves of Byrsonima verbascifolia (L.) Rich., Roupala montana Aubl. and Solanum lycocarpum A. St.-Hil. growing in phytophysiognomies at two distinct altitudes. We evaluated leaf anatomy, the quantum yield of photosystem II, and the photosynthetic pigments in plants occurring at two areas of Campo sujo, which are separated by 700 m of altitude, during the rainy season. The three plant species occurring at higher altitudes had thicker adaxial epidermis. B. verbascifolia and S. lycocarpum occurring at higher altitudes had thicker palisade parenchyma, whereas only B. verbascifolia had thicker spongy parenchyma at the same site. The quantum yield of photosystem II, and photosynthetic pigments had little differences between plants occurring at higher and lower altitudes. The results analysed show high structural modifications and low physiological alterations from altitudinal conditions. Thus, the influence of the abiotic factors appears to modulate the plastic responses of plants across altitude.
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Bloch, Konrad E., Jana C. Buenzli, Tsogyal D. Latshang und Silvia Ulrich. „Sleep at high altitude: guesses and facts“. Journal of Applied Physiology 119, Nr. 12 (15.12.2015): 1466–80. http://dx.doi.org/10.1152/japplphysiol.00448.2015.
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Lowlanders commonly report a poor sleep quality during the first few nights after arriving at high altitude. Polysomnographic studies reveal that reductions in slow wave sleep are the most consistent altitude-induced changes in sleep structure identified by visual scoring. Quantitative spectral analyses of the sleep electroencephalogram have confirmed an altitude-related reduction in the low-frequency power (0.8-4.6 Hz). Although some studies suggest an increase in arousals from sleep at high altitude, this is not a consistent finding. Whether sleep instability at high altitude is triggered by periodic breathing or vice versa is still uncertain. Overnight changes in slow wave-derived encephalographic measures of neuronal synchronization in healthy subjects were less pronounced at moderately high (2,590 m) compared with low altitude (490 m), and this was associated with a decline in sleep-related memory consolidation. Correspondingly, exacerbation of breathing and sleep disturbances experienced by lowlanders with obstructive sleep apnea during a stay at 2,590 m was associated with poor performance in driving simulator tests. These findings suggest that altitude-related alterations in sleep may adversely affect daytime performance. Despite recent advances in our understanding of sleep at altitude, further research is required to better establish the role of gender and age in alterations of sleep at different altitudes, to determine the influence of acclimatization and of altitude-related illness, and to uncover the characteristics of sleep in highlanders that may serve as a study paradigm of sleep in patients exposed to chronic hypoxia due to cardiorespiratory disease.
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Ma, Hailin, Buxin Han und Yan Wang. „Different neurocognitive patterns of conflict control in Tibetans living above and below 4,000 m“. PeerJ 7 (08.07.2019): e7269. http://dx.doi.org/10.7717/peerj.7269.
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Background The existence of a particular threshold of hypoxia severity, beyond which neuropsychological functioning is compromised, is unclear. We investigated the neurocognitive profile related to conflict control in healthy young Tibetans born and living at three different altitudes (2,700 m, 3,700 m, and 4,500 m) in Tibet to investigate the existence of this threshold. Methods Using event-related potentials (ERPs), the conflict control functions of individuals in the three altitude groups were investigated by means of a flanker task, using congruent and incongruent stimuli. The data were analyzed using mixed-model analyses of variance. Results Although effect of altitude was not significant at a behavioral level (p > 0.05), the ERPs showed cognitive conflict modulation. The N2 difference wave (for incongruent minus congruent conditions) was smaller in the 4,500-m group than in the groups living below 4,000 m (p < 0.05). The study’s findings suggest that the influence of high altitude in the conflict monitoring stage becomes significant above 4,000 m. Thus, the altitude threshold for impairment of cognition may be 4,000 m.
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Qiu, Zhihong, Xi Chu, Cesar Calvo-Ramirez, César Briso und Xuefeng Yin. „Low Altitude UAV Air-to-Ground Channel Measurement and Modeling in Semiurban Environments“. Wireless Communications and Mobile Computing 2017 (2017): 1–11. http://dx.doi.org/10.1155/2017/1587412.
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Small- and medium-sized unmanned aerial vehicles (UAVs) can fly for a short distance (<2 km) from a control station in a nonsegregated air space (altitudes < 100 m). It is of great interest to model the propagation channel under such condition, where there is an important influence from the environment. This paper presents multiple measurements carried out in low altitudes with a medium-sized UAV flying over a semiurban environment. Path loss exponent is given based on the measurements done at different altitudes and a height-dependent Rician K factor model is proposed. The results clearly reveal the existence of two propagation zones with very distinct channel characteristics. The breakpoint indicates the height where the condition of the channel changes rapidly. At low altitudes, the obstacles generate a large amount of multipath and the propagation is greatly affected, while at higher altitudes the influence mitigates. Our results are useful for the modeling of low altitude air-to-ground (AG) propagation channels and the performance analysis of UAV-enabling AG communication systems, such as the channel capacity and the throughput.
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Hudson, James G., Stephen Noble und Vandana Jha. „Comparisons of CCN with Supercooled Clouds“. Journal of the Atmospheric Sciences 67, Nr. 9 (01.09.2010): 3006–18. http://dx.doi.org/10.1175/2010jas3438.1.
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Abstract More than 140 supercooled clouds were compared with corresponding out-of-cloud cloud condensation nuclei (CCN) measurements. In spite of significant differences in altitude, temperature, distances from cloud base, updraft velocity (W), entrainment, and so on, the correlation coefficients (R) between droplet and CCN concentrations were substantial although not as high as those obtained in warm clouds with less variability of nonaerosol influences. CCN at slightly lower altitudes than the clouds had higher R values than CCN measured at the same altitude. Ice particle concentrations appeared to reduce droplet concentrations and reduce R between CCN and droplet concentrations, but only above 6-km altitude and for temperatures below −20°C. Although higher CCN concentrations generally resulted in higher droplet concentrations, increases in droplet concentrations were generally less than the increases in CCN concentrations. This was apparently due to the expected lower cloud supersaturations (S) when CCN concentrations are higher as was usually the case at lower altitudes. Cloud supersaturations showed more variability at higher altitudes and often very high values at higher altitudes. The use of liquid water content rather than droplet concentrations for cloud threshold resulted in higher R between CCN and droplet concentrations. The same R pattern for cumulative droplet–CCN concentrations as a function of threshold droplet sizes as that recently uncovered in warm clouds was found. This showed R changing rapidly from positive values when all cloud droplets were considered to negative values for slightly larger droplet size thresholds. After reaching a maximum negative value at intermediate droplet sizes, R then reversed direction to smaller negative or even positive values for larger cloud droplet size thresholds. This R pattern of CCN concentrations versus cumulative droplet concentrations for increasing size thresholds is consistent with adiabatic model predictions and thus suggests even greater CCN influence on cloud microphysics.
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Liu, Xiaoli. „Influence Of Altitude Difference On Residents’ Physical Function“. Medicine & Science in Sports & Exercise 49, Nr. 5S (Mai 2017): 249–50. http://dx.doi.org/10.1249/01.mss.0000517535.99531.6d.
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Wyss, Christophe A., Pascal Koepfli, Gregory Fretz, Magdalena Seebauer, Christian Schirlo und Philipp A. Kaufmann. „Influence of Altitude Exposure on Coronary Flow Reserve“. Circulation 108, Nr. 10 (09.09.2003): 1202–7. http://dx.doi.org/10.1161/01.cir.0000087432.63671.2e.
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Xu, Liang, und Yuanli Cai. „Influence of altitude on aero-optic imaging deviation“. Applied Optics 50, Nr. 18 (14.06.2011): 2949. http://dx.doi.org/10.1364/ao.50.002949.
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Mayer, Z., A. Epperlein, R. Volk, E. Vollmer und F. Schultmann. „Comparison of building thermography approaches using terrestrial and aerial thermographic images“. IOP Conference Series: Earth and Environmental Science 1078, Nr. 1 (01.09.2022): 012026. http://dx.doi.org/10.1088/1755-1315/1078/1/012026.
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Abstract Thermography is commonly used for auditing buildings. Classical manual terrestrial thermography records images of individual buildings at a short distance. When auditing a large number of buildings (e.g. whole city districts) this approach reaches its limits. Using drones with thermographic cameras allows images to be recorded automatically from different angles, with faster speed and without violating property rights. However, an airborne camera has a significantly greater distance and more varied angles to a building compared to terrestrial thermography. To investigate the influence of these factors for building auditing, we perform a study evaluating seven different drone settings of varying flight speed, angle, and altitude. A comparison is drawn to manually recorded terrestrial thermographic images. While we find that a flight speed between 1m/s and 3m/s does not influence the thermographic quality, high flight altitudes and steep viewing angles lead to a significant reduction of visible details, contrast, and to falsified temperatures. A flight altitude of 12m over buildings is found to be the most suitable for the qualitative and quantitative analysis of rooftops and a qualitative analysis of façades. A flight altitude of 42m over buildings can only be used for qualitative audits with little detail.
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Nazari, Noorollah, Mohsen Bahmani, Saleh Kahyani, Miha Humar und Gerald Koch. „Geographic Variations of the Wood Density and Fiber Dimensions of the Persian Oak Wood“. Forests 11, Nr. 9 (17.09.2020): 1003. http://dx.doi.org/10.3390/f11091003.
Annotation:
Persian oak (Quercus brantii Lindl.) is a valuable native species in Iranian forests with very limited availability of data on its wood properties. The objective of the current study was to determine the influence of altitude and slope on physical properties and fiber dimensions of Persian oak wood. In addition, the relationship among wood properties, site conditions (temperature and rainfall) and growth traits of trees (tree height, DBH, basal area, age, crown diameter, crown basal area, volume and annual diameter increment) were studied by principal component analysis (PCA). Three altitude levels (1730, 1980 and 2250 m) and three slope classes (<30%, 30–45% and >45%) were considered in the current study. It was determined that trees growing in the intermediate altitude (1980 m) showed the highest oven-dry density values, and those in the lowest altitude (1730 m) revealed the lowest ones. The results also indicate significant statistical differences between altitude levels and slope classes on the fiber length, fiber diameter and volumetric swelling at the 99% confidence interval while no significant differences were found between average values of oven-dry density among different altitudes and slopes. PCA analysis indicated that altitude and temperature are the most important factors affecting the wood properties. Knowledge of the relationship between wood properties and environmental factors are essential in terms of both forestry management and wood applications.
46
Damiani, A., M. Storini, M. L. Santee und S. Wang. „Variability of the nighttime OH layer and mesospheric ozone at high latitudes during northern winter: influence of meteorology“. Atmospheric Chemistry and Physics Discussions 10, Nr. 6 (11.06.2010): 14583–610. http://dx.doi.org/10.5194/acpd-10-14583-2010.
Annotation:
Abstract. Analyses of OH zonal means, recorded at boreal high latitudes by the Aura Microwave Limb Sounder (MLS), have shown medium- (weeks) and short-term (days) variability of the nighttime OH layer. Because of the exceptional descent of air from the mesosphere-lower thermosphere region, medium-term variability occurred during February 2006 and February/March 2009. The layer normally situated at about 82 km descended by about 5–7 km, and its density increased to more than twice January values. In these periods and location the abundance of the lowered OH layer is comparable with the OH values induced by Solar Energetic Particle (SEP) forcing (e.g. SEP events of January 2005) at the same altitudes. In both years, the drop of the OH layer was coupled with increased mesospheric temperatures, elevated carbon monoxide and an almost complete disappearance of ozone at the altitude of the descended layer (which was not observed in other years). Moreover, under these exceptional atmospheric conditions, the third ozone peak is shown descending to lower altitude and increasing its abundance, with maximum values recorded during February 2009. Short-term variability occurred during Sudden Stratospheric Warming (SSW) events, in particular in January 2006, February 2008 and January 2009, when dynamics led to a smaller abundance of the OH layer at its typical altitude. The upward extension of the OH layer coupled to changes in ozone and carbon monoxide is shown to be strongest during the SSW of January 2009, coincident with the lowest upper mesospheric temperatures recorded at that time of year during 2005–2009. Finally, the series of SSW events that occurred in late January/February 2008 induced noticeable short-term variability in ozone at altitudes of both the ozone minimum and the third ozone peak. These phenomena, confined inside the polar vortex, are an additional tool that can be used to investigate mesospheric vortex dynamics.
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Penížek, V., und T. Zádorová. „Soil toposequence under man-planted vegetation in the Krkonoše Mts., Czech Republic“. Soil and Water Research 7, No. 4 (09.11.2012): 138–50. http://dx.doi.org/10.17221/11/2012-swr.
Annotation:
Mountainous areas represent regions with specific soil cover pattern that is naturally given by an altitudinal gradient. The objective of our study was to describe the soil cover development on the altitudinal gradient under changed environment given by man-planted vegetation and acidification. The studied area is characterized by spruce monoculture planting that replaced the original broadleaf natural vegetation and high load of anthropic acidification. The common hypothesis considering the sequence of Dystric Cambisol-Entic Podzol-Haplic Podzol with increasing altitude was not proved. The results of our study indicate that the influence of spruce vegetation causes the occurrence of Haplic Podzols at low altitudes where the natural soil formation does not induce their development. Results showed that the vegetation type can overrule other altitude-related soil-forming factors. The conversion of natural broadleaf and mixed forests to spruce monocultures leads to the expansion of podzolization process to lower altitudes.
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Nadeem, Tarana, und Yuliya Tyravska. „ALTERATION IN THROMBOGENIC PARAMETERS AS A POTENTIAL RAMIFICATION OF HIGH ALTITUDE INFLUENCE ON INDIVIDUALS“. InterConf, Nr. 15(117) (20.07.2022): 224–33. http://dx.doi.org/10.51582/interconf.19-20.07.2022.023.
Annotation:
The peculiarity of alteration in platelet indices among other physiological changes on adaptation to high altitude is controversial. This review has revealed insufficient information about how changes in platelet indices can be attributed as a consequence of high-altitude terrain. Further clinical trials are necessary to understand the potential relation between high altitude and changes in thrombocytes and their activity.
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Obrenovic, Jovisa, Milkica Nesic, Vladimir Nesic und Snezana Cekic. „Formant structure of the voice during the intensive acute hypoxia“. Vojnosanitetski pregled 60, Nr. 2 (2003): 155–59. http://dx.doi.org/10.2298/vsp0302155o.
Annotation:
The influence of intensive acute hypoxia on the frequency-amplitude formant vocal O characteristics was investigated in this study. Examinees were exposed to the simulated altitudes of 5 500 m and 6 700 m in climabaro chamber and resolved Lotig?s test in the conditions of normoxia, i.e. pronounced the three-digit numbers beginning from 900, but in reversed order. Frequency and intensity values of vocal O (F1, F2, F3 and F4) extracted from the context of the pronunciation of the word eight (osam in Serbian), were measured by spectral speech signal analysis. Changes in frequency values and the intensity of the formants were examined. The obtained results showed that there were no significant changes of the formant frequencies in hypoxia condition compared to normoxia. Though significant changes of formant?s intensities were found compared to normoxia on the cited altitudes. The rise of formants intensities was found at the altitude of 5 500 m. Hypoxia at the altitude of 6 700 m caused the significant fall of the intensities in the initial period, compared to normoxia. The prolonged hypoxia exposure caused the rise of the formant intensities compared to the altitude of 5 500 m. In may be concluded that due to different altitudes, hypoxia causes different effects on the formants structure changes, compared to normoxia.
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Maisch, M. „Die Gletscher um "1850" und "HEUTE" im Bünderland und in den angrenzenden Gebieten : Untersuchungen zur Höhenlage, Veränderungen und räumlichen Struktur von Schneegrenzen“. Geographica Helvetica 42, Nr. 2 (30.06.1987): 127–45. http://dx.doi.org/10.5194/gh-42-127-1987.
Annotation:
Abstract. An inventory of data for the extent of ice in 1850 is presented and compared to the extent of alpine glaciers in 1973 as recorded by the Swiss glacier inventory. Special attention is given to the position and spatial Variation of snowline altitudes based on data for the general ice retreat between 1850 and 1973. The ränge of snowline altitudes (as given by the 2 :1 -equilibrium line calculation) reflects the topography and the related change from wet perialpine to dry continental inneralpine areas. In addition, the effects of local condition are superimposed on this trend. The overall climatically induced rise in snowline altitudes between 1850 and 1973 is 77 +/-51 m. The considerable ränge of 340 m as compared to the actual Situation in 1973 demonstrates the influence of local topography, geometry and dip of the glacier surface on the snowline altitude. The mean altitude of the firnline in 1973 quantifies the melting during the last year of Observation 1972/73. The glaciers in the regions of Bernina, Bergell and Kesch are more strongly affected than in other areas during this budget period. On the average, the firnline altitude rose 120 m above de 2 :1 - equilibrium line corresponding to the surface geometry of that year. The data presented and the climatological information will be analysed and deciphered in more details.