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de Aquino Lemos, Valdir, Ronaldo Vagner Thomatieli dos Santos, Fabio Santos Lira, Bruno Rodrigues, Sergio Tufik e 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.
Testo completoAbstract (sommario):
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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Shangpliang, P. Wankitlang, Rupa Nylla K. Hooroo, Graham Bakynson Ranee, Sudhanya Ray Hajong, Annu Kumari e Eugene Lyngkhoi. "Exploring Altitude's Influence: Contrasting Embryonic Development of Hyla annectans Jerdon in High and Low Altitude Environments". UTTAR PRADESH JOURNAL OF ZOOLOGY 45, n. 7 (21 marzo 2024): 1–9. http://dx.doi.org/10.56557/upjoz/2024/v45i73967.
Testo completoAbstract (sommario):
The study investigated the embryonic development of Hyla annectans Jerdon, a frog species, at high and low altitude breeding sites of Meghalaya, North East India. Results revealed significant differences in the duration of embryonic development and hatching between the two altitudes. Embryos at low altitude sites exhibited a faster development, hatching approximately four days earlier than those at high altitude sites. Early embryonic stages displayed similar characteristics in size between the two sites, but distinct differences emerged during later stages, notably in stages associated with heart development, muscular response, and gill circulation. Furthermore, metamorphosis completion varied between altitudes, with a shorter duration observed at low altitude compared to high altitude. Environmental conditions, particularly water properties, also differed significantly between the two sites. Water temperature and free carbon dioxide levels were higher at low altitude, while pH and dissolved oxygen levels were higher at high altitude. These findings suggest a potential influence of altitudinal gradients as environmental factors on embryonic development in H. annectans.
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Tang, Yan Fei, Chao Ding, Ya Ping He, De Chuang Zhou e Jian Wang. "Studies on the Effect of Altitude on the Flammable Liquids' Flash Point". Advanced Materials Research 908 (marzo 2014): 345–48. http://dx.doi.org/10.4028/www.scientific.net/amr.908.345.
Testo completoAbstract (sommario):
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 e TERSI ALESTI. "Karakteristik Fisiologis Lumut pada Beberapa Ketinggian di Kawasan Gunung Tangkuban Perahu". Jurnal Sumberdaya Hayati 1, n. 2 (4 maggio 2016): 60–63. http://dx.doi.org/10.29244/jsdh.1.2.60-63.
Testo completoAbstract (sommario):
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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Xie, Gongliang, Sen Liu, Ting Chang e Ninghua Zhu. "Forest Adaptation to Climate Change: Altitudinal Response and Wood Variation in Natural-Growth Cunninghamia lanceolata in the Context of Climate Change". Forests 15, n. 3 (21 febbraio 2024): 411. http://dx.doi.org/10.3390/f15030411.
Testo completoAbstract (sommario):
This research delves into the impact of climate change on the wood traits of Cunninghamia lanceolata across various altitudinal gradients, aiming to understand the influence of altitude and climatic factors like temperature and precipitation on key wood characteristics. Employing a comprehensive approach, samples were collected from different altitudes for detailed phenotypic analysis. Methods included Pearson correlation, principal component analysis, cluster analysis, and random forest analysis. Results revealed significant variations in wood traits such as heartwood ratio, tracheid length, and width across altitudes. Notably, wood traits in lower- and middle-elevation populations exhibited higher variability compared to higher elevations, indicating greater environmental diversity and genetic adaptability at these altitudes. Climatic factors, particularly temperature and precipitation, were found to increasingly influence wood trait variation with altitude. The research concludes that the adaptation of Cunninghamia lanceolata to climate change is significantly influenced by both altitudinal and climatic factors, highlighting their importance in forest genetic breeding and conservation strategies amidst global climate change.
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Bordjan, Dejan, e Davorin Tome. "Nest survival of Great Tit Parus major in spatial and temporal gradient". Acta Biologica Slovenica 56, n. 1 (1 luglio 2013): 55–63. http://dx.doi.org/10.14720/abs.56.1.15549.
Testo completoAbstract (sommario):
The aim of the study was to compare nest survival of Great Tit between different regions, altitudes and years to discern which has the highest influence. Temperature is known to be prominent for breeding parameters and it changes consistently with altitude. Our hypothesis was that altitude has greater influence on nest survival than the region and year. Breeding parameters were monitored with the use of nestboxes over a three year period at three altitude belts in two regions. The main factor influencing nesting success was modelled using daily survival rate in the program MARK. We gathered data from 104 first nesting attempts of which 26 failed. Although nest failure increased with altitude this was significant only for one region. There was significant difference in nest failure between the regions but not between the years. Modelling showed higher support in data for regions than for altitudes and years thus rejecting the hypothesis. Some possible reasons for such results are discussed.
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Spring, Allison M., Kenneth D. Domingue, Thomas V. Kerber, Margaret M. Mooney, Rebecca L. Hale, Kristina M. Lemmer e Kathryn M. Docherty. "Land Use Effects on Airborne Bacterial Communities Are Evident in Both Near-Surface and Higher-Altitude Air". Diversity 13, n. 2 (18 febbraio 2021): 85. http://dx.doi.org/10.3390/d13020085.
Testo completoAbstract (sommario):
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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Zakraoui, Mariem, Hédia Hannachi, Igor Pasković, Nikolina Vidović, Marija Polić Pasković, Igor Palčić, Nikola Major, Smiljana Goreta Ban e Lamia Hamrouni. "Effect of Geographical Location on the Phenolic and Mineral Composition of Chetoui Olive Leaves". Foods 12, n. 13 (30 giugno 2023): 2565. http://dx.doi.org/10.3390/foods12132565.
Testo completoAbstract (sommario):
In this study, we investigated the influence of pedological parameters and variation of altitude on the mineral nutrients, phenolic compounds, and antioxidant activities of olive leaves. Samples of the Chetoui cultivar were collected from eight geographical locations with different altitudes. Levels of phenolic compounds varied according to the altitude. Classification of the locations revealed that altitude 1 (>500 m) was characterized by high levels of secoiridoids and simple phenols, while altitude 2 (500–300 m) and altitude 3 (<300 m) were higher in flavonoids. Levels of Mn, Ca and B in the leaves and level of Zn in the soil were significantly correlated with the abundance of oleuropein and luteolin-7-O glucoside, the most important phenols in Chetoui olive leaves. The results suggest that, in addition to pedological criteria, environmental conditions also influence the formation of phenolic compounds.
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Rohima, Ira Endah, Mohamad Djali, Yana Cahyana, Jajang Sauman Hamdani e Mohd Nizam Lani. "Effect of Cultivation at Different Altitudes on the Chemical, Functional and Pasting Properties of Starch Medians Cultivar Potato (Solanum tuberosum L.)". INTERNATIONAL JOURNAL OF AGRICULTURAL AND STATISTICAL SCIENCES 20, n. 01 (giugno 2024): 33. http://dx.doi.org/10.59467/ijass.2024.20.33.
Testo completoAbstract (sommario):
The cultivation elevation of potatoes plays a crucial role that influences starch quality. Little is known on the impact of varying altitudes on starch quality. Therefore, this new study analyzed the starch attributes of the Median?s potato variety (Solanum tuberosum L.) cultivated at three distinct altitudinal zones: lowlands, midlands, and highlands. The objective was to elucidate the impact of these varying altitudes on the chemical composition, functional qualities and pasting behavior of starch derived from the Median?s cultivar. Utilizing a randomized block design with quadruplicate trials, the data was subjected to one-way ANOVA and Duncan?s Multiple Range Test, at a 5% significance threshold. The results show that highland and midland plantings yielded a higher starch production. The cultivation altitude had a significant influence (p < 0.05) on several chemical parameters of the starch, including its moisture, protein, lipid content, total starch, amylose, ash and phosphorus contents. The functional properties, such as swelling volume, solubility, water and oil absorption capacities, syneresis, gel strength, and colors (a*, b*, L* values) also exhibited significant variance with altitude. Furthermore, pasting qualities also were altered by the altitude of potatoes cultivation. X-Ray Diffraction (XRD), particle size analysis, granule morphology via microscopy and Fourier Transform Infrared Spectroscopy (FTIR), revealed significant differences (p < 0.05) across starches from different altitudes, confirming the influence of environmental conditions on starch quality and its functional properties. These results provide valuable recommendations for customizing potato farming methods to enhance starch yield and their applications in various food production sectors.. KEYWORDS :Cultivation altitude, Cultivar, Farming methods, Functional properties, Starch quality.
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Lei, Tian, Jinliang Xu, Xingli Jia, Leyu Wei e 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 agosto 2019): 1–14. http://dx.doi.org/10.1155/2019/8560204.
Testo completoAbstract (sommario):
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., e Tim Brodribb. "Altitude of origin influences stomatal conductance and therefore maximum assimilation rate in Southern Beech, Nothofagus cunninghamii". Functional Plant Biology 27, n. 5 (2000): 451. http://dx.doi.org/10.1071/pp99164.
Testo completoAbstract (sommario):
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 e 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, n. 4 (aprile 2018): 180188. http://dx.doi.org/10.1098/rsos.180188.
Testo completoAbstract (sommario):
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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Carvalho, Biange Maria Cezário de, Raquel Leite Wainfas, Tayanna Rodrigues, Lidiane Coelho Berbert, Thaiane Franklin, Ivyn Karla Lima de Sousa e 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, n. 1 (24 agosto 2016): 1. http://dx.doi.org/10.24021/raac.v13i1.3314.
Testo completoAbstract (sommario):
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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Wang, Shuling, Zhe Shao e Jie Li. "THE INFLUENCE OF VARIATION IN ALTITUDE ON ATHLETIC PERFORMANCE IN LONG-DISTANCE RUNNERS". Revista Brasileira de Medicina do Esporte 28, n. 5 (ottobre 2022): 584–86. http://dx.doi.org/10.1590/1517-8692202228052022_0101.
Testo completoAbstract (sommario):
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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Yang, Xue, Long Di Cheng, Li Qian Huang e Wen Hong Fan. "Study on the Correlation between the Property of Akund Fiber and its Growing Conditions". Advanced Materials Research 476-478 (febbraio 2012): 1934–38. http://dx.doi.org/10.4028/www.scientific.net/amr.476-478.1934.
Testo completoAbstract (sommario):
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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Höffner, J., e J. S. Friedman. "Metal layers at high altitudes: A possible connection to meteoroids". Atmospheric Chemistry and Physics Discussions 4, n. 1 (20 gennaio 2004): 399–417. http://dx.doi.org/10.5194/acpd-4-399-2004.
Testo completoAbstract (sommario):
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., e J. S. Friedman. "The mesospheric metal layer topside: a possible connection to meteoroids". Atmospheric Chemistry and Physics 4, n. 3 (26 maggio 2004): 801–8. http://dx.doi.org/10.5194/acp-4-801-2004.
Testo completoAbstract (sommario):
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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Hevko, Bohdan, e Jurii Bondar. "Influence of flight mode on loads from turbulent air". MECHANICS OF GYROSCOPIC SYSTEMS, n. 42 (28 dicembre 2022): 117–27. http://dx.doi.org/10.20535/0203-3771422021268893.
Testo completoAbstract (sommario):
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 e 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.
Testo completoAbstract (sommario):
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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Ferreira, Anna Carolyna Fernandes, Felipe Vaz Andrade, Eduardo de Sá Mendonça e Paulo Roberto da Rocha Júnior. "Land use and altitude: how do they influence the phosphorus fractions?" Acta Scientiarum. Agronomy 44 (24 maggio 2022): e54801. http://dx.doi.org/10.4025/actasciagron.v44i1.54801.
Testo completoAbstract (sommario):
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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Bambang Kholiq Mutaqin, Didin Supriat Tasripin, Lia Budimulyati Salman, Iin Susilawati e Ujang Hidayat Tanuwiria1. "Comparisons and influence temperature humidity index to dairy cow productivity based on farm altitude". Agrivet : Jurnal Ilmu-Ilmu Pertanian dan Peternakan (Journal of Agricultural Sciences and Veteriner) 12, n. 1 (4 giugno 2024): 13–18. http://dx.doi.org/10.31949/agrivet.v12i1.9458.
Testo completoAbstract (sommario):
This study aimed to determine the differences and effects of the Temperature Humidity Index (THI) on dairy cows’ productivity in West Java based on differences in farm altitude. Categorization based on area altitude can be divided into low altitude (<700 m asl), moderate (700-1000 m asl), and high (> 1,000 m asl). The parameters observed were body size, body weight, and milk production which were supplemented by environmental conditions namely temperature and humidity. The method used is a survey and direct observation by simple random sampling of animals. The results showed differences in environmental conditions, namely temperature and humidity in each dairy farm with different altitudes. Meanwhile, the performance of milk production is relatively the same even though variations in the performance of body measurements and weight of dairy cows in each region. It can be concluded that heat environmental conditions with high THI can cause cows to suffer from heat stress so that productivity decreases.
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Bordjan, Dejan. "Nestling growth of Great Tits Parus major with comparison among altitudes". Acta Biologica Slovenica 56, n. 1 (1 luglio 2013): 45–53. http://dx.doi.org/10.14720/abs.56.1.15548.
Testo completoAbstract (sommario):
Fledgling mass can have great influence on individual’s life history and reflects the availability and quality of food in the breeding territory. Thus growth curve is used to compare the difference in the quality between different ecological conditions. The aim of the study was to fill the knowledge gap on nestling growth in Great Tit in Slovenia, to determine the influence of altitude on it and to present a tool for estimating age of nestlings and key dates in breeding phenology of Great Tit. Great Tits young were monitored using nest-boxes at three locations between years 2010 and 2012. At two locations nest-boxes were placed on three separate altitudinal belts. Weight growth curve was compared with the curves from other parts of Europe. Growth curve from Slovenia differs in growth parameters from other European populations but falls within their range. Difference in growth parameters betweenseparate populations probably comes from the difference in ecological conditions. When comparing three altitudes weight parameters of hatchlings were similar at lower and middle but different at upper altitudes indicating that weigh growth changes with the altitude. Lower food abundance that comes with rising altitude may be offset by lower competition through lower breeding density (hence similar growth parameters in lower and middle altitude), but not past certain altitude. Weight parameters are usefulwhen comparing different populations, but wing-length is better in determining the age of young in the nest.
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Chi Lin, Bo Zhang, Xiaolong Zhao, Donglin Xu, Taoxi Zong, Yong Shen, Yanxiang Tong, Shiying Chen, Weihua Chu e Linjie Wei. "Hyperuricemia as a risk factor for cerebral hemorrhage in young and middle-aged hypertensive patients at high altitude". Neurology Asia 29, n. 2 (giugno 2024): 293–300. http://dx.doi.org/10.54029/2024jyx.
Testo completoAbstract (sommario):
Background: The purpose of this research was to investigate the effect of uric acid on hypertensive intracerebral hemorrhage (HICH) in young and middle-aged hypertensive patients at high altitude. Methods: High-altitude and low-altitude HICH patients were analyzed retrospectively, and the influence of uric acid on hemorrhage was analyzed by the correlations between age and uric acid, between age and hemoglobin, and between uric acid and hemoglobin. The individuals in the high- and low-altitude groups were assigned to a young/middle-aged group and an elderly group, and the correlation between age and uric acid was analyzed. The risk factors for HICH were analyzed by logistic regression analysis. ROC curve analysis was used to investigate the relationship between risk factors and cerebral hemorrhage. Results: Age was negatively correlated with uric acid concentration in patients with HICH at high altitudes but not in patients with HICH at low altitudes. In addition, age was negatively correlated with hemoglobin in patients with HICH at high altitudes but not in patients with HICH at low altitudes. Uric acid was negatively correlated with age in young and middle-aged adults at high altitudes but not in elderly individuals. Diastolic pressure, uric acid and sex were risk factors for HICH in young and middle-aged adults at high altitudes. ROC curve showed that uric acid and diastolic pressure had diagnostic significance. Conclusions: High levels of uric acid is correlated with increased risk of cerebral hemorrhage in young and middle-aged adults with hypertension in high altitude.
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Girma, Bealu, Abera Gure e Feyisa Wedajo. "Influence of Altitude on Caffeine, 5-Caffeoylquinic Acid, and Nicotinic Acid Contents of Arabica Coffee Varieties". Journal of Chemistry 2020 (12 agosto 2020): 1–7. http://dx.doi.org/10.1155/2020/3904761.
Testo completoAbstract (sommario):
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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Liang, Tao, Weilin Tao, Yan Wang, Na Zhou, Wei Hu, Tao Zhang, Dunxiu Liao, Xinping Chen e Xiaozhong Wang. "The Extension of Vegetable Production to High Altitudes Increases the Environmental Cost and Decreases Economic Benefits in Subtropical Regions". Land 12, n. 3 (11 marzo 2023): 662. http://dx.doi.org/10.3390/land12030662.
Testo completoAbstract (sommario):
Global warming has driven the expansion of cultivated land to high-altitude areas. Intensive vegetable production, which is generally considered to be a high economic value and high environmental risk system, has expanded greatly in high-altitude mountainous areas of China. However, the environmental cost of vegetable production in these areas is poorly understood. In this study, pepper production at low (traditional pepper production area) and high (newly expanded area) altitudes were investigated in Shizhu, a typical pepper crop area. The output and environmental cost at the two altitudes were identified. the influence of resource inputs, climate, and soil properties on pepper production was evaluated. There were obvious differences in output and environmental cost between the two altitudes. High-altitude pepper production achieved a 16.2% lower yield, and had a higher fertilizer input, resulting in a 22.3% lower net ecosystem economic benefit (NEEB), 23.0% higher nitrogen (N) footprint and 24.0% higher carbon (C) footprint compared to low-altitude farming. There is potential for environmental mitigation with both high- and low-altitude pepper production; Compared to average farmers, high-yield farmers groups reduced their N and C footprints by 16.9–24.8% and 18.3–25.2%, respectively, with 30.6–34.1% higher yield. A large increase in yield could also be achieved by increasing the top-dress fertilizer rate and decreasing the plant density. Importantly, high-altitude pepper production was achieved despite less advanced technology and inferior conditions (e.g., a poor road system and uneven fields). It provides a reference for the study of the environmental cost of other high-altitude regions or other crop systems at high-altitude areas.
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Roșian, Gheorghe, Csaba Horvath, Liviu Muntean e Nicolae Baciu. "The Influence of Landform in the Distribution of Households of Ilva Mică Territorial Administrative Unit". Studia Universitatis Babeș-Bolyai Ambientum 66, n. 1-2 (30 novembre 2022): 53–62. http://dx.doi.org/10.24193/subbambientum.2021.05.
Testo completoAbstract (sommario):
"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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Coman, Năstaca-Alina, Mihai Babotă, Ingrid Nădășan, Alexandru Nicolescu, Alexandru Robert Pitaru, Ruxandra Ștefănescu, Andrei Mocan, Oleg Frumuzachi e Corneliu Tanase. "The Influence of Ecological Factors on the Phytochemical Characteristics of Pinus cembra L." Applied Sciences 13, n. 18 (11 settembre 2023): 10184. http://dx.doi.org/10.3390/app131810184.
Testo completoAbstract (sommario):
Pinus cembra L., also known as Swiss pine, is one of the lesser studied coniferous species, despite literature pointing out its great potential to be used for medical purposes due to its high contents in active phytochemicals. The aim of this study is to phytochemically assess rhytidome and periderm extracts obtained from Swiss pine from various locations and altitudes, so as to be able to deduce the best locations for harvesting samples with the highest biological activity. After the plant was analyzed histo-anatomically, hydroalcoholic extracts were obtained using ultrasounds, a rotary evaporator, and dry freezing. After determining the total polyphenolic content (TPC) in each sample, they were tested for antioxidant and enzymatic activity, while taking note of the influence of the varying altitudes and different harvesting regions on the intensity of each activity. The results from the TPC analysis show that rhytidome samples collected from the highest altitude (2429 m) displayed the highest content of polyphenols, with a general tendency for the amount of polyphenolic content to be directly correlated to altitude, this finding being further supported by the antioxidant activity also growing directly proportionally with the altitude. Enzymatic inhibition activity was found to be moderate for α-glucosidase and low for α-amylase. Following our findings, we can safely say that Pinus cembra L. extracts can be a great source of compounds with antioxidant activity; however, further studies are warranted to best determine the true potential of this species.
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Zhang, Rongrong, e Daifen Chen. "Investigation of Diesel Spray Characteristics in Low-temperature and Low-pressure Conditions". Bulletin of Science and Practice 10, n. 5 (15 maggio 2024): 383–96. http://dx.doi.org/10.33619/2414-2948/102/48.
Testo completoAbstract (sommario):
This study investigates the influence of altitude and injection pressure on diesel fuel spray characteristics, aiming to optimize diesel usage in high-altitude conditions. Experiments were conducted at three altitude levels (plains, 1670 m, and 2400 m) with corresponding atmospheric pressures and temperatures, alongside six injection pressures ranging from 50 MPa to 100 MPa. The investigation focused on key spray parameters: equivalence ratio, spray penetration velocity, turbulence kinetic energy, evaporation rate, spray penetration distance, and Sauter Mean Diameter (SMD). Findings indicate that increased injection pressure enhances spray penetration velocity, evaporation rate, and turbulence kinetic energy, while reducing SMD, irrespective of altitude. Conversely, higher altitudes were associated with increased spray penetration speed, larger SMD, decreased evaporation rate, increased turbulence, and a higher equivalence ratio. The study concludes that both altitude and injection pressure significantly impact diesel spray characteristics, providing essential theoretical support for the application and optimization of diesel fuels in varied altitude conditions.
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Duan, Yanan, Yuwen Liu, Yan Cheng, Ming Jiang e Zhiyuan Zhang. "Research on Artillery Firing Trajectory under the Condition of Extra-large Elevation Difference between Artillery and Target in Plateau Area". Journal of Physics: Conference Series 2460, n. 1 (1 aprile 2023): 012038. http://dx.doi.org/10.1088/1742-6596/2460/1/012038.
Testo completoAbstract (sommario):
Abstract Get the influence of shooting on the ballistic elements and correction elements of grenade under the condition of extra-large elevation difference between artillery and target in plateau area through simulation, and drawn the comparison chart of different altitude and elevation difference between artillery and target by using the simulation data. Calculate the variation characteristics of the hit range of laser terminal guided projectile under the condition of the elevation difference of extra-large elevation difference between artillery and target at different altitudes, and the influence of altitude and extra-large elevation difference between artillery and target on the hit range of laser terminal guided projectile is analyzed and summarized. It has a certain reference value for improving the shooting accuracy under the condition of high altitude and extra-large elevation difference between artillery and target.
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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 e Arumugam Vijaya Anand. "Influence of SERPINA1 Gene Polymorphisms on Anemia and Chronic Obstructive Pulmonary Disease". Journal of the Renin-Angiotensin-Aldosterone System 2022 (17 ottobre 2022): 1–8. http://dx.doi.org/10.1155/2022/2238320.
Testo completoAbstract (sommario):
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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Peng, Qikai, Ruilin Liu, Guangmeng Zhou, Xumin Zhao, Surong Dong e Zhongjie Zhang. "Study on Through-Flow Characteristics of a Diesel Two-Stage Supercharged Centrifugal Compressor under Variable-Altitude and Multiple Operating Conditions". Processes 12, n. 1 (23 dicembre 2023): 46. http://dx.doi.org/10.3390/pr12010046.
Testo completoAbstract (sommario):
Understanding the influence of environmental boundary parameters on the through-flow characteristics of two-stage supercharged centrifugal compressors is the key to maximizing the power recovery potential of diesel engines at high altitudes. In this paper, the influence of the compressor through-flow characteristics on the full-load thermal cycle performance of a diesel engine under variable altitude is studied by means of tests and simulation. The results show that with the increase in altitude, the range of stable work flow decreases, and the pressure ratio of the plugging point changes greatly with altitude. The efficiency of the compressor with the same mass flow point decreases, and the highest efficiency point moves in the direction of the small flow range. With the goal of maximizing the torque of the diesel engine under full load and low speed, the key geometric parameters of the variable-altitude through-flow characteristics of the two-stage supercharged compressor were optimized as follows: at the altitudes of 0 m, 2500 m, and 5500 m, the diesel engine torque increased by 5.89%, 3.78%, and 2.18%, respectively. Based on the optimization method of the compressor through-flow design, a new direction is provided to break through the research on the independent limitation of the diesel engine thermal cycle performance optimization and compressor flow control.
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Chen, Yongming, Zehua Chang, Shiguo Xu, Peng Qi, Xiaoyu Tang, Yang Song e Dongmei Liu. "Altitudinal Gradient Characteristics of Spatial and Temporal Variations of Snowpack in the Changbai Mountain and Their Response to Climate Change". Water 13, n. 24 (14 dicembre 2021): 3580. http://dx.doi.org/10.3390/w13243580.
Testo completoAbstract (sommario):
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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Wang, Wei, Xiangru Fu, Cong Wei, Yuanyuan Wang e Shi Chen. "Study on Temperature Field in Common-rail Diesel Engine Combustion Chamber at Different Altitudes". Journal of Physics: Conference Series 2650, n. 1 (1 novembre 2023): 012038. http://dx.doi.org/10.1088/1742-6596/2650/1/012038.
Testo completoAbstract (sommario):
Abstract The plateau covers 26% of China’s land area, the higher altitude, the lower atmospheric pressure, the smaller air density, the lower average temperature. Therefore diesel engine power decreases significantly, fuel consumption increases, starting performance deteriorates, and soot emissions increase. In this paper, virtual simulation and simulation test methods are used to study the temperature field change in the combustion chamber of CA6DL2-35E3R common-rail diesel engine at different altitudes and atmospheric pressures. The results show that the altitude has a great influence on the temperature field in the combustion chamber. The maximum combustion temperature gradually increases with increase of altitude, post-combustion is serious and the exhaust temperature increases.
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AYKUT, Medeni, e İhsan TUĞAL. "The influence of Altitude on the Species Composition of Diving Beetles (Coleoptera; Adephaga; Dytiscidae) of Eastern and South Eastern Region of Turkey". Journal of the Institute of Science and Technology 13, n. 3 (7 agosto 2023): 1573–84. http://dx.doi.org/10.21597/jist.1330703.
Testo completoAbstract (sommario):
This study was carried out between 2013 and 2019 in five provinces located in Eastern and South Eastern Anatolian Region of Turkey. The dytiscid specimens were collected from a total of 226 sampling sites that altitudes varied between 500 and 2,700 meters. The 226 sampling sites were classified into one of six altitudinal levels defined by semi open intervals with amplitude of 300 m. A total of 45 species belonging to the family Dytiscidae were identified. A detailed ecological analysis related to altitude is made by means of the distribution of 45 identified species. The richness of species was analyzed at different altitudinal levels. The indicator species were determined by establishing their altitude profile in terms of reciprocal species-factor information. The species density is highest in altitudinal level 2 (800-1100m) and is gradually decrease by increasing of altitudinal level. Ten representative species are placed into three groups: species occurring at high altitude; species present at low altitude and species occurring along the entire altitudinal gradient.
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Swayze, Neal C., Wade T. Tinkham, Matthew B. Creasy, Jody C. Vogeler, Chad M. Hoffman e Andrew T. Hudak. "Influence of UAS Flight Altitude and Speed on Aboveground Biomass Prediction". Remote Sensing 14, n. 9 (21 aprile 2022): 1989. http://dx.doi.org/10.3390/rs14091989.
Testo completoAbstract (sommario):
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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Xiao, Yanping, Furui Wang e Peiyan Sun. "Numerical simulation of two-dimensional plain flap ground effect based on NACA4412 airfoil". Journal of Physics: Conference Series 2756, n. 1 (1 maggio 2024): 012049. http://dx.doi.org/10.1088/1742-6596/2756/1/012049.
Testo completoAbstract (sommario):
Abstract Based on the NACA4412 airfoil, by solving a two-dimensional unsteady Reynolds-averaged N-S equation and using the k-ωSST model, this paper analyzes the influence of near-ground altitude change on different configuration flow fields under moving ground conditions and explores the variation law of wing pressure coefficient at different near-ground altitudes. The results show that the attraction of the upper airfoil is weakened by the GE (ground effect), the pressure of the lower airfoil is increased, and the upper and lower airfoils influence the lift change of the airfoil. With the decrease of near-ground altitude, at a certain AOA (angle of attack), the greater the flap angle is, the faster the suction loss on the upper wing surface is and the slower the pressure increases on the lower wing surface, and the lower the near-ground altitude corresponding to the minimum lift coefficient is. With the decrease of near-ground altitude, at a certain flap angle, the greater the AOA is, the faster the suction loss on the upper wing surface is and the slower the pressure increases on the lower wing surface, and the lower the near-earth altitude corresponding to the minimum lift coefficient is.
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Peña-Avelino, Luz Y., Ivonne Ceballos-Olvera, Gerardo N. Rosales-Martinez, Javier Hernández-Melendez e Jorge Alva-Pérez. "Milk Composition of Creole Goats Raised at Different Altitudes in an Extensive Production System in Northeast Mexico". Animals 13, n. 11 (24 maggio 2023): 1738. http://dx.doi.org/10.3390/ani13111738.
Testo completoAbstract (sommario):
Goat milk composition is affected by feeding, and in semiarid rangeland, information on Creole goat milk physicochemical composition is lacking. For the fulfillment of this objective, three agroecological regions (AR) considering altitude (lowland 87, highland 779, and mountain 1309 m above sea level) with different botanical compositions were chosen. Every AR analyzed accounted for 30 goat herds, with a total of 90 herds. The results demonstrated that altitude had an influence mainly on density and protein. Milk density increases as altitude increases; conversely, milk protein increases as altitude decreases. On the other hand, in the mountain and lowland ARs, the salts and solids not fat (SNF) percentages were higher compared to that of the highland AR (p < 0.05). The freezing point (FP) was higher at highland altitudes compared to that of mountain and lowland ARs (p < 0.01). In the milk fatty acids (FA) profile, only the C14:1 value was affected by altitude, whereas goat milk at lowland and mountain altitudes had higher values compared to that at highland altitudes (p < 0.05). Additionally, late lactation stage fat, FP, and pH values were higher compared to early lactation values. The opposite effect was observed for salts and SNF. In the FA profile, late lactation values were higher for C10:0 and C8:0 compared to early lactation values. The opposite trend was observed for C18:2n6t. The thrombogenic index was significantly higher at lowland altitudes compared to highland altitudes, and similar to the mountain AR. These goat milk characteristics could be explained as a consequence of animal nutrition, as well as the goat’s meat-type phenotype.
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Zhu, Yanbin, Jiayi Tian, Yangji Cidan, Hongzhuang Wang, Kun Li e Wangdui Basang. "Influence of Varied Environment Conditions on the Gut Microbiota of Yaks". Animals 14, n. 11 (25 maggio 2024): 1570. http://dx.doi.org/10.3390/ani14111570.
Testo completoAbstract (sommario):
Despite the crucial role of the gut microbiota in different physiological processes occurring in the animal body, reports regarding the gut microbiota of animals residing in different environmental conditions like high altitude and different climate settings are limited. The Qinghai–Tibetan Plateau is renowned for its extreme climatic conditions that provide an ideal environment for exploring the effects of high altitude and temperature on the microbiota of animals. Yaks have unique oxygen delivery systems and genes related to hypoxic response. Damxung, Nyêmo, and Linzhou counties in Tibet have variable altitudes and temperatures that offer distinct settings for studying yak adaptation to elevated terrains. The results of our study suggest that amplicon sequencing of V3-V4 and internal transcribed spacer 2 (ITS2) regions yielded 13,683 bacterial and 1912 fungal amplicon sequence variants (ASVs). Alpha and beta diversity indicated distinct microbial structures. Dominant bacterial phyla were Firmicutes, Bacteroidota, and Actinobacteriota. Genera UCG-005, Christensenellaceae_R-7_group, and Rikenellaceae_RC9_gut_group were dominant in confined yaks living in Damxung county (DXS) and yaks living in Linzhou county (LZS), whereas UCG-005 prevailed in confined yaks living in Nyêmo county (NMS). The linear discriminant analysis effect size (LEfSe) analysis highlighted genus-level differences. Meta-stat analysis revealed significant shifts in bacterial and fungal community composition in yaks at different high altitudes and temperatures. Bacterial taxonomic analysis revealed that two phyla and 32 genera differed significantly (p < 0.05). Fungal taxonomic analysis revealed that three phyla and four genera differed significantly (p < 0.05). Functional predictions indicated altered metabolic functions, especially in the digestive system of yaks living in NMS. This study reveals significant shifts in yak gut microbiota in response to varying environmental factors, such as altitude and temperature, shedding light on previously unexplored aspects of yak physiology in extreme environments.
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Malfatti, Eduardo, Pedro M. A. Ferreira e Laura R. P. Utz. "Eukaryotic Communities in Bromeliad Phytotelmata: How Do They Respond to Altitudinal Differences?" Diversity 12, n. 9 (28 agosto 2020): 326. http://dx.doi.org/10.3390/d12090326.
Testo completoAbstract (sommario):
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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Bateman, Brooke L., Alex S. Kutt, Eric P. Vanderduys e Jeanette E. Kemp. "Small-mammal species richness and abundance along a tropical altitudinal gradient: an Australian example". Journal of Tropical Ecology 26, n. 2 (29 gennaio 2010): 139–49. http://dx.doi.org/10.1017/s0266467409990460.
Testo completoAbstract (sommario):
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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Saha, Sushil, Govind-Singh Rajwar e Munesh Kumar. "Forest structure, diversity and regeneration potential along altitudinal gradient in Dhanaulti of Garhwal Himalaya". Forest Systems 25, n. 2 (20 luglio 2016): e058. http://dx.doi.org/10.5424/fs/2016252-07432.
Testo completoAbstract (sommario):
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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Mahari, Abraham, Clinton G. Blasin, Aberash Bekele e Anthony T. Watson. "Exploring the Influence of Slope Gradient on Tree Species Richness and Forest Structure". Asian Journal of Biology 20, n. 3 (19 febbraio 2024): 25–33. http://dx.doi.org/10.9734/ajob/2024/v20i3394.
Testo completoAbstract (sommario):
Slope gradient is a critical environment factor influencing the abundance, distribution and diversity of vegetation. The objective of this study was to exploring the influence of slope gradient on tree species richness and forest structure in Kpatawee forest, Liberia. Tree diameter was measured at breast height for species more than 5 cm in diameter and over 3 m in height. Tree species diversity was analyzed using Shannon diversity index (Hˈ). Basal area (BA) which is the cross-sectional area of tree stems was measured through the diameter at breast height that is 1.3 m above ground level. Results showed that a total of 26 tree species were identified from the total sampling area (0.36 ha). The three richest families: Moraceae, Rutaceae and Euphorbiaceae appear to be well represented in the Kpatawee forest. These families become outnumbered in the herbaceous except for the Rutaceae family, which is ranked second. This is mainly due to their adaptation potential to wider agro-ecologies. Tree species richness was higher in the lower altitude. High species abundance was recorded in the lower altitude followed by the middle and upper. The lowest Shannon diversity index value (H' = 1.85) and the highest value (H' = 2.28) were recorded in the upper, and the lower altitudes, respectively. Despite their values, the biodiversity did not vary greatly from altitude to altitude. Diameter class distribution showed that more species were in the lower diameter classes and decreased gradually towards the higher classes. It is recommended that further studies on the entire Kpatawee forest is needed to fully understand the species richness in the forest.
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Amelunke, Michael, Carlton P. Anderson, Margaret C. B. Waldron, George T. Raber e Gregory A. Carter. "Influence of Flight Altitude and Surface Characteristics on UAS-LiDAR Ground Height Estimate Accuracy in Juncus roemerianus Scheele-Dominated Marshes". Remote Sensing 16, n. 2 (18 gennaio 2024): 384. http://dx.doi.org/10.3390/rs16020384.
Testo completoAbstract (sommario):
Management and monitoring of vulnerable coastal marshes rely on accurate ground height estimates. However, marsh surface characteristics such as vegetation and water presence complicate aerial remote sensing of the ground. Towards developing an improved understanding and techniques for these remote sensing efforts, this study established relationships among data collection flight altitude, surface characteristics, and ground height estimate accuracy within Juncus roemerianus Scheele-dominated marshes. Uncrewed Aerial System (UAS) Light Detection and Ranging (LiDAR) sampling was conducted at five altitudes for five marsh sites and one local control site. Survey-grade topographic measurements and marsh surface characteristics were recorded at each site for comparison. Root Mean Square Error (RMSE) and linear mixed-effects modeling were used to quantify relationships among vertical error, altitude, and surface characteristics. For low (24–72 m) and high (96–120 m) altitudes Above Ground Level (AGL), the RMSE values were 49 cm and 17 cm, respectively. Despite this appreciable improvement in accuracy with increasing flight altitude, point density values of these datasets limit applications. Linear mixed-effects modeling further emphasized the complex relationships between sensor footprint size, surface characteristics, and ground height estimates. These findings have direct implications for elevation modeling and monitoring efforts of frequently inundated, coastal marshes.
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Franzén, Markus, e Petra Dieker. "The influence of terrain age and altitude on the arthropod communities found on recently deglaciated terrain". Current Zoology 60, n. 2 (1 aprile 2014): 203–20. http://dx.doi.org/10.1093/czoolo/60.2.203.
Testo completoAbstract (sommario):
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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ABADA, O., H. KBAB e S. HAIF. "Optimizing the design of a supersonic Planar Dual Bell Nozzle (PDBN)". Kosmìčna nauka ì tehnologìâ 30, n. 2 (29 aprile 2024): 15–27. http://dx.doi.org/10.15407/knit2024.02.015.
Testo completoAbstract (sommario):
Dual bell nozzles present a promising solution for maximizing propulsion efficiency at high altitudes, while also mitigating dangerous side loads at lower altitudes. Such nozzles are comprised of two distinct contours, with the first optimized for low altitude operation, and the second tailored for high altitude conditions. These contours are interconnected at an inflexion point. The present study focuses on optimizing the contour design of a planar dual bell nozzle. Leveraging the commercial ANSYS-Fluent software, we conducted an investigation into the influence of the inflection angle on the transition between the two operating modes, examined the flow behavior inside the nozzle, and assessed the impact of the inflection angle on the thrust coefficient.
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Seifert, Erich, Stefan Seifert, Holger Vogt, David Drew, Jan van Aardt, Anton Kunneke e Thomas Seifert. "Influence of Drone Altitude, Image Overlap, and Optical Sensor Resolution on Multi-View Reconstruction of Forest Images". Remote Sensing 11, n. 10 (27 maggio 2019): 1252. http://dx.doi.org/10.3390/rs11101252.
Testo completoAbstract (sommario):
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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Cook, James D., Erick Boy, Carol Flowers e Maria del Carmen Daroca. "The influence of high-altitude living on body iron". Blood 106, n. 4 (15 agosto 2005): 1441–46. http://dx.doi.org/10.1182/blood-2004-12-4782.
Testo completoAbstract (sommario):
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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Dotdaeva, A. A., Kh A. Kurdanov e S. A. Boytsov. "MORBIDITY AND MORTALITY FROM CARDIOVASCULAR DISEASES ACCORDING TO THE SEA-LEVEL RELATED ALTITUDE OF A REGION". Cardiovascular Therapy and Prevention 13, n. 6 (28 dicembre 2014): 51–55. http://dx.doi.org/10.15829/1728-8800-2014-6-51-55.
Testo completoAbstract (sommario):
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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Tian, Xiaomiao, Si Chen, Qiusheng Zhong, Junyu Wang, Jiedan Chen, Liang Chen, Doogyung Moon e Jianqiang Ma. "Widely Targeted Metabolomics Analysis Reveals the Effect of Cultivation Altitude on Tea Metabolites". Agronomy 14, n. 4 (13 aprile 2024): 812. http://dx.doi.org/10.3390/agronomy14040812.
Testo completoAbstract (sommario):
Cultivation altitude is a comprehensive environmental factor that significantly affects tea quality. To gain a deeper understanding of the effect of cultivation altitude on tea metabolites, a widely targeted metabolomic method based on ultra-performance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS) was used to analyze tea samples derived from three altitudes (86 m, 256 m, and 880 m) of two cultivars, ‘Mingke 1’ (MK) and ‘Fuyun 6’ (FY). The results showed that distinct groups of tea samples from different altitudes and cultivars were observed based on PCA. A total of 64 and 56 altitude-related differential metabolites were identified in MK and FY, respectively. Among them, 16 compounds were consistent in both cultivars and were clustered in the metabolic pathways for flavonoid (11 compounds), amino acid (3), and fatty acid (2). The content of all flavonoids and one amino acid (L-aspartic acid) gradually decreased with increasing altitude; on the contrary, the others showed an opposite trend. Furthermore, we identified 57 differential metabolites between two cultivars. Two specific compounds (8-C-hexosyl chrysoeriol O-hexoside and pelargonidin 3-O-β-D-glucoside) were exclusively found in MK, while one compound (4-hydroxybenzoic acid) was present only in FY. These findings offer insight into the metabolic responses of tea plants to different altitudes, providing further understanding on the influence of the environment on tea plants.
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Qin, Pengcheng, Mingnian Wang, Zhanwen Chen, Guanfeng Yan, Tao Yan, Changling Han e Anmin Wang. "Effects of Ambient Pressure on Burning Characteristics of Gasoline: A Pilot Study". Energies 14, n. 15 (30 luglio 2021): 4627. http://dx.doi.org/10.3390/en14154627.
Testo completoAbstract (sommario):
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.