Effect Of Altitude Research Articles

Groundwater composition and stable isotopes as proxies to investigate paleoclimate change in permafrost thawing regions

The paleoclimate since the late Pleistocene has gained substantial attention due to its profound effects on hydrology, ecosystems, and landforms, particularly in regions experiencing permafrost thawing. Northeast China is acknowledged for exhibiting distinctive yet contentious paleoclimate, which has been elucidated through various proxies. In this case, we emphasize the significance of stable isotopes within the northern Songnen Plain as complementary proxies for paleoclimate interpretation, bolstered by radiocarbon dating. The Cretaceous sandstone confined aquifer (CSA) is designated as the reference aquifer, based on the hydrogeochemical and isotopic characteristics. The 14C results indicate that the CSA preserves groundwater from the late Pleistocene to the modern. These findings, in conjunction with isotope variations, delineate specific climate events, which are aligning with results derived from conventional proxies. The late Pleistocene-early Holocene showed a climate shift from cold to warm. The middle Holocene was warm and humid. Then the late Holocene entered the Neoglacial, which characterized by a cold climate environment. Our analysis also reveals fluctuations in the age and TDS concentration along the groundwater runoff. The paleo groundwater exhibits simultaneous lower TDS concentration, maximum δ18O depletion and minimum recharge temperature. Neither latitude nor altitude effects could account for the sufficient isotopic depletion, instead, we found that the humid climate and permafrost meltwater also contributed to the isotope depletion. Simultaneously, the paleoclimatic environment such as freeze-thaw cycles of permafrost exerts a significant influence on the groundwater. The formation of permafrost hinders groundwater recharge, while its thawing dilutes the solute content of groundwater. Additionally, the recharge gaps also potentially result from arid climate, inadequate samples, and the effects of mixing water. The study substantiates the reliability of confined aquifers in permafrost thawing regions as robust paleoclimatic archives and emphasizes the utility of stable isotopes in combination with radiocarbon dating as ideal climate proxies.

Evaluation of Radio Frequency Identification Power and Unmanned Aerial Vehicle Altitude in Plant Inventory Applications

In the business of growing and selling ornamental plants, it is important to keep track of plants from nursery to distribution. Radio Frequency Identification (RFID) technology provides an easier tracking method for inventories of plants by attaching tags with unique identifiers. Due to the vast area of most nurseries, there is a need to have an efficient method of scanning RFID tags. This paper investigates the use of drones and RFID, specifically, the effects of RFID reader power and flight altitude on tag counts. The experimental setup evaluated three RFID reader power levels (15 dBm, 20 dBm, and 27 dBm), three flight altitudes (3 m, 5 m, and 7 m), the number of passes (one or two), and two plant types (‘Green Giant’ arborvitae and ‘Sky Pencil’ holly). For RFID tags, four types were used (L5, L6, L8, and L9), with two antenna types (dog-bone and square-wave) and two attachment types (loop-lock and stake). For each power level, the UAV was flown to three different altitudes of 3 m, 5 m, and 7 m above the ground. At each altitude, two scan passes were performed at a constant speed of approximately 1.5 m/s. Each plot of plants (two in total) was randomly tagged with a total of 40 RFID tags per plot. Field data were collected from September to December 2023 (on a total of eight dates). The data showed that a power level of 15 dBm and an altitude of 3 m yielded a tag count of 53%, while counts of 34% and 16% were achieved at 5 m and 7 m, respectively. At 20 dBm and an altitude of 3 m, the count accuracy across all tag types and both plants was 90%. When the altitude was increased to 5 m and 7 m, tag-count accuracy dropped to 75% and 33%, respectively. The highest count accuracy was observed at 27 dBm and an altitude of 3 m, with a reading accuracy of 98%. Tag types L6 and L9 performed better at any power level and altitude, while L5 and L8 performed well at a higher power level and lower altitude. In this experiment, canopy properties (size and shape) had no effect on the number of tags read. This study aimed to evaluate the RFID power and UAV altitude achieving the highest accuracy in scanning the RFID tags. Furthermore, it also assessed the effects of plant growth on the scanning efficiency and accuracy of the system.

Revolutionary Design and Optimization of Railway Electrification Overhead Equipment in High-Altitude Tunnels: A Case Study of the Magnificent T-80 Tunnel

Railway electrification systems are critical for modernizing railway infrastructure, enhancing efficiency, and reducing environmental impact to obtain zero emissions targets. In high-altitude regions, such as mountainous terrains, unique challenges arise due to extreme weather conditions, terrain complexities, and operational requirements. This case study focuses on the innovative and optimized design of overhead equipment (OHE) for railway electrification in high-altitude tunnels, presenting a comprehensive analysis of the planning, design, and implementation process for 25kV AC Overhead equipment. The study begins with an overview of significant considerations in designing 25kV AC OHE systems for high-altitude tunnels, including altitude effects on electrical performance, weather effects, structural safety checks, fire scenarios, vibration effects, and tunnel bolt drilling for OHE equipment installation. It also covers aspects such as the selection of auto tensioning devices, electrical clearances, and earthing & bonding according to railway/EN/IEC standards. Also, the paper examines the monetary feasibility and environmental sustainability of the proposed OHE design, emphasizing the importance of life-cycle cost analysis and environmental impact valuation. It underscores the significance of adopting a holistic approach that balances technical requirements, operational efficiency, and environmental stewardship in railway electrification projects.

Hydrochemistry and isotope hydrology of groundwater and surface water in the Sor and Gebba watershed, southwestern Ethiopia

The Sor and Gebba watershed plays a crucial role in the water resources of the Baro-Akobo River Basin. However, various factors have had a detrimental effect on the watershed. Unplanned groundwater extraction, wetland drainage, surface water pollution, and land use changes have all intensified due to population growth, urbanization, commercial farms, industrial development, poor water resources management, and improvements in living standards. This research utilized major hydrochemical ions and environmentally stable isotopes to elucidate the interaction between groundwater and surface water in the watershed, which are reliable tracers in various hydrologic processes. During the 2020 wet season and 2022 dry season, over 25 meteoric water samples were collected from different locations for hydrochemical and isotopic analysis. The hydrochemical analysis revealed that the dominant water type is Ca–Mg–HCO3−. Among the anions, HCO3− was the most dominant, followed by NO3−, Cl−, and SO42−, and those of cations Ca2+, followed by Na+, Mg2+, and K+. The spatial analysis of environmentally stable isotopes confirmed the interaction between groundwater and surface water in the watershed. The quality of groundwater is primarily influenced by rock-water interaction (Gibb's diagram) and, to some extent, by evaporation (Isotope study). A graph of the water samples closely aligned with the Addis Ababa-local meteoric water line indicates their meteoric origin. However, there was a slight deviation to the left due to the effects of distance and altitude. The isotopic correlation further supported the interaction between different water sources.

Practical considerations for continuous glucose monitoring in elite athletes with type 1 diabetes mellitus: A narrative review.

Type 1 diabetes mellitus (T1DM) refers to a metabolic condition where a lack of insulin impairs the usual homeostatic mechanisms to control blood glucose levels. Historically, participation in competitive sport has posed a challenge for those with T1DM, where the dynamic changes in blood glucose during exercise can result in dangerously high (hyperglycaemia) or low blood glucoses (hypoglycaemia) levels. Over the last decade, research and technological development has enhanced the methods of monitoring and managing blood glucose levels, thus reducing the chances of experiencing hyper- or hypoglycaemia during exercise. The introduction of continuous glucose monitoring (CGM) systems means that glucose can be monitored conveniently, without the need for frequent fingerpick glucose checks. CGM devices include a fine sensor inserted under the skin, measuring levels of glucose in the interstitial fluid. Readings can be synchronized to a reader or mobile phone app as often as every 1-5min. Use of CGM devices is associated with lower HbA1c and a reduction in hypoglycaemic events, promoting overall health and athletic performance. However, there are limitations to CGM, which must be considered when being used by an athlete with T1DM. These limitations can be addressed by individualized education plans, using protective equipment to prevent sensor dislodgement, as well as further research aiming to: (i) account for disparities between CGM and true blood glucose levels during vigorous exercise; (ii) investigate the effects of temperature and altitude on CGM accuracy, and (iii) explore of the sociological impact of CGM use amongst sportspeople without diabetes on those with T1DM.

Optimal attitude planning along torque equilibrium points using aerodynamic database for deorbiting large space debris

Currently, considerable attention is being directed toward active debris removal (ADR) using small, cost-effective satellites. From high altitude to re-entry, ADR missions use thrusters that consume significant amounts of fuel. The volume of the propulsion system in these satellites can be quite large, and it is difficult for a small satellite to accommodate a large-scale propulsion system. Thus, active utilization of atmospheric drag is being considered for small satellites with low capability. However, the principal challenge for small satellites to remove large debris is to deal with the large disturbance torque caused by strong atmospheric drag on the debris. This paper proposes attitude guidance around an equilibrium (balance) point in attitude dynamics acted on by gravity gradient and aerodynamic torques. The desired attitude is set to optimize two conflicting objectives: maximizing the projection area to generate large aerodynamic force and minimizing the disturbance torque. In this paper, we develop an aerodynamic database (ADDB) by rigorously calculating the aerodynamic torque for each altitude and solar array paddle (SAP) rotation based on an aerodynamic characteristic model of free molecular flow. Using the ADDB, the SAP angle and orbit altitude effects on the torque equilibrium attitude (TEA) are clarified. Then, the mean disturbance torque map at each orbit altitude is introduced to obtain the candidate TEA paths. The effectiveness of the proposed paths for debris descent is demonstrated through numerical simulations.

Identification and quality evaluation of Lushan Yunwu tea from different geographical origins based on metabolomics

The relationship between the chemical composition and quality of Lushan Yunwu tea (LYT) from different geographical origins is not clear. Sensory evaluation, metabolomics analyses combined with chemometrics were conducted on LYT from 8 different geographical origins, and altitude was identified as the main factor responsible for the differences among LYT. A total of 32 non-volatile and 27 volatile compounds were identified as marker metabolites to distinguish the origins of high altitudes from those of low altitudes. LYT samples from higher altitude areas contained more free amino acids, sugars, and organic acids, and less catechins, which may contribute to the reduction of bitterness and astringency and the enhancement of umami. The contents of geranylacetone, ethyl hexanoate, ethyl caprylate, 3-carene, d-cadinene, linalool, nerol, and nerolidol in high altitude areas were higher than those in low altitude areas, indicating that LYT from high altitude had strong floral and fruity aroma. The altitudes were positively correlated with pH value, total flavonoids, soluble protein, total free amino acids, and the antioxidant capacities of the LYT. This study provided a theoretical basis for the study of the effect of altitude on tea quality.

Widely Targeted Metabolomics Analysis Reveals the Effect of Cultivation Altitude on Tea Metabolites

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.

‘Sultan’ alıç çeşidinde yükselti ve yetiştirme sezonunun meyve kalite özelliklerine etkileri

Bu çalışma, ‘Sultan’ alıç çeşidinde iki farklı yükselti (117 m/Antakya ve 812 m/Belen) ve üç yetiştirme sezonunun (2020, 2021 ve 2022 yılları) bazı fenolojik dönemlere ve meyve kalite özelliklerine etkisini belirlemek amacıyla yürütülmüştür. Çalışmada fenolojik özelliklerden ilk çiçeklenme, tam çiçeklenme, çiçeklenme sonu ve hasat tarihi belirlenmiştir. Meyve kalite özelliklerinden meyve ağırlığı (g), meyve eni (mm), meyve boyu (mm), çekirdek sayısı (adet meyve-1), çekirdek ağırlığı (g adet-1), yenilebilir meyve oranı (%), suda çözünebilir kuru madde içeriği (SÇKM %), pH ve titre edilebilir asit içeriği (TEA %) değerlendirilmiştir. Ayrıca, meyve kabuk ve et rengi ölçümleri yapılmıştır. Elde edilen sonuçlara göre, ‘Sultan’ çeşidinin çiçeklenme dönemleri, hasat tarihi ve meyvenin fiziksel özelliklerinin yükselti ve yetiştirme sezonu tarafından etkilendiği belirlenmiştir. ‘Sultan’ alıç çeşidinin 117 m yükseltideki ortalama tam çiçeklenmesi ve hasat tarihi 812 m’ye göre sırasıyla ortalama 15 gün ve 22 gün daha erken gerçekleşmiştir. Ancak, ‘Sultan’ çeşidinin 812 m rakımdaki ortalama meyve ağırlığının 117 m rakıma göre %28.74 daha yüksek olduğu belirlenmiştir. Sonuç olarak, ‘Sultan’ alıç çeşidinde özellikle meyve iriliği bakımından 812 m ve erkencilik bakımından 117 m yükseltide yetiştiriciliğinin ön plana çıktığı söylenebilir.

Prevalence of Lifestyle Diseases in Non-Acclimatized Lowlanders at High Altitude in subdivision Darjeeling district of Eastern Himalayan Region, India

Background: Lifestyle diseases including overweight, obesity, hypertension and metabolic syndrome leads toheart diseases, increased risk for insulin resistance, diabetes and stroke. Obesity is one of the lifestyle diseases declared as worldwide epidemic which is a major health burden. The study determine the association of lifestylediseases with Body Mass Indexinnon-acclimatized lowlanders at altitude of 7500 ft above sea level and to estimate effect of altitude on anthropometric and biochemical parameters.Methods: The total of 300 male age between 20-57 years studied. The present retrospective study was done using Annual Medical Examination documents which were recorded at plains and at high altitude. The anthropometric indexes observed using Asia-pacific criteria from the World Health Organization and biochemical parametersobserved using metabolic syndrome according to the American Heart Association.Conclusion: The present study comprises of maximum cases of young adults at plains and middle-aged at high altitude. The maximum overweight cases were found at high altitude and general obese cases found at plains. There is a slight risk of hypertension and deranged lipid profile at this altitude but no risk of polycythaemia. The present study’s indicator of abdominal obesity at high altitude is the waist-hip ratio. Increase in altitude causes changes in body mass index, blood glucose levels and lipid profile. Additionally, positive correlation found between lifestyle diseases such as central or abdominal obesity(r=0.33,P<0.05) and diastolic blood pressure (r=0.19,P<0.05) with Body Mass Index at high altitude. The present study agreed with the various studies from India and abroad.

Changes in health-promoting metabolites associated with high-altitude adaptation in honey

The levels of metabolites in honey are influenced by floral origin, production region, and bee species. However, how environmental factors affect honey quality remains unclear. Based on untargeted metabolomics and using UPLC Q-Orbitrap MS, we analyzed 3596 metabolites in 51 honey samples from Yunnan and Shennongjia. Comparative analysis revealed that geniposidic acid, kynurenic acid and caffieine accumulated at significantly different levels between Shennongjia and Yunnan honey. Based on cluster structure analysis, 36 Yunnan honey samples were divided into two distinct groups by altitude. Notably, quercetin, hyperoside, taxifolin, rutin, tryptophan, astragalin and phenylalanine were higher levels in high-altitude honey (>1700 m), whereas abscisic acid was higher levels in low-altitude honey (≤1700 m). Among these, significantly elevated levels of hyperoside, taxfolin, astragalin, and tryptophan were observed in honey collected from high-altitude areas in Shennongjia. Our findings highlight the effect of altitude on honey health-promoting components, providing valuable insights into honey quality.

Optimisation of a liquid cooling system for eVTOL aircraft: Impact of sizing mission and battery size

High-energy and -power density lithium-ion batteries (LiB) can enable viable electric vertical take-off and landing (eVTOL) aircraft for advanced air mobility provided that their battery thermal management system (BTMS) allows safe and efficient operations with acceptable weight penalties and capacity degradation. In this paper, we present the first optimisation of a liquid-cooled LiB BTMS for a notional tilt-wing reference eVTOL aircraft. Using an in-house developed BTMS sizing and battery degradation modelling algorithm, we investigate the effects of cruise altitude, hover duration, and battery pack oversizing on BTMS weight and battery lifetime. We minimise the BTMS weight, power, and battery temperature. The optimisation results reveal that varying cruise altitude has a negligible effect on BTMS design. While an extended hover duration does not adversely impact degradation, a considerably heavier BTMS is needed. The BTMS is about twice as heavy when the hover duration increases from one to seven minutes. Shortening the flight distance or oversizing the battery pack greatly impacts the battery lifespan. The battery capacity degradation rate halves when increasing the battery pack size by 20%.

The Pleistocene high-elevation environments between 2.02 and 0.6 Ma at Melka Kunture (Upper Awash Valley, Ethiopia) based upon stable isotope analysis

Pleistocene environments are among the most studied issues in paleoecology and human evolution research in eastern Africa. Many data have been recorded from archaeological sites located at low and medium elevations (≤ 1500 m), whereas few contexts are known at 2000 m and above. Here, we present a substantial isotopic study from Melka Kunture, a complex of prehistoric sites located at 2000—2200 m above sea level in the central Ethiopian highlands. We analyzed the stable carbon and oxygen isotopic composition of 308 faunal tooth enamel samples from sites dated between 2.02 and 0.6 Ma to investigate the animal diets and habitats. The carbon isotopic results indicate that the analyzed taxa had C4-dominated and mixed C3-C4 diets with no significant diachronic changes in feeding behavior with time. This is consistent with faunal and phytolith analyses, which suggested environments characterized by open grasslands (with both C3 and C4 grasses), patches of bushes and thickets, and aquatic vegetation. However, palynological data previously documented mountain forests, woodlands, and high-elevation grasslands. Additionally, the carbon isotopic comparison with other eastern African localities shows that differences in elevation did not influence animal feeding strategies and habitat partitioning, even though plant species vary according to altitudinal gradients. In contrast, the oxygen isotopic comparison suggests significant differences consistent with the altitude effect. Our approach allows us to detect diverse aspects of animal behavior, habitat, and vegetation that should be considered when reconstructing past environments.

Hemorrhage at high altitude: impact of sustained hypobaric hypoxia on cerebral blood flow, tissue oxygenation, and tolerance to simulated hemorrhage in humans.

With ascent to high altitude (HA), compensatory increases in cerebral blood flow and oxygen delivery must occur to preserve cerebral metabolism and consciousness. We hypothesized that this compensation in cerebral blood flow and oxygen delivery preserves tolerance to simulated hemorrhage (via lower body negative pressure, LBNP), such that tolerance is similar during sustained exposure to HA vs. low altitude (LA). Healthy humans (4F/4M) participated in LBNP protocols to presyncope at LA (1130m) and 5-7days following ascent to HA (3800m). Internal carotid artery (ICA) blood flow, cerebral delivery of oxygen (CDO2) through the ICA, and cerebral tissue oxygen saturation (ScO2) were determined. LBNP tolerance was similar between conditions (LA: 1276 ± 304s vs. HA: 1208 ± 306s; P = 0.58). Overall, ICA blood flow and CDO2 were elevated at HA vs. LA (P ≤ 0.01) and decreased with LBNP under both conditions (P < 0.0001), but there was no effect of altitude on ScO2 responses (P = 0.59). Thus, sustained exposure to hypobaric hypoxia did not negatively impact tolerance to simulated hemorrhage. These data demonstrate the robustness of compensatory physiological mechanisms that preserve human cerebral blood flow and oxygen delivery during sustained hypoxia, ensuring cerebral tissue metabolism and neuronal function is maintained.

Predicted distribution of Metaparasitylenchus hypothenemi (Tylenchida: Allantonematidae), parasite of the coffee berry borer.

Metaparasitylenchus hypothenemi is an endoparasitic nematode of the coffee berry borer Hypothenemus hampei. The nematode has only been recorded across a limited geographical range in coffee-growing areas of southeastern Mexico. Because of its confined geographical distribution, the effect of altitude, temperature, and mean annual precipitation on M. hypothenemi's presence/absence in the Soconusco region of Mexico was investigated. The geographical distribution of this parasite was predicted based on current data, using geographical information systems (GIS), the MaxEnt algorithm, and historical data to improve the prediction accuracy for other Neotropical regions. In Soconusco, the presence of this parasite is directly related to annual precipitation, especially in the areas with the highest annual rainfall (4000 - 4700 mm/year). Four species distribution models were generated for the Neotropical region with environmental variables for sites with parasite presence data, predicting a range of possible distribution with a high probability of occurrence in southeastern Mexico and southwestern Guatemala and a low probability in areas of Central and South America. Characterization of the abiotic habitat conditions suitable for M. hypothenemi development allows us to predict its distribution in the Neotropics and contributes to our understanding of its ecological relationship with environmental variables.

Investigation of speed and altitude effects on sound exposure level calculations for multiple helicopters

International and United States Federal regulations evaluate helicopter acoustic emissions for certification purposes as well as community noise impact assessments. The Sound Exposure Level (SEL) is a commonly used metric that represents the loudness of a single event, with a penalty for duration. For example, a flyover lasting ten seconds can have the same SEL as a five-second duration flyover that is 6 dB higher in peak level. Ten helicopters spanning the light and medium weight classes were modeled using flight test data. They were then virtually flown using the Advanced Acoustic Model at multiple speeds and altitudes. SEL and A-weighted SEL (SELA) were calculated at ground-based observer locations for each condition. Scaling laws with altitude are determined, and cruising airspeeds which result in the minimum SEL are found. Implications for future land-use planning will be discussed, and the relationships are reduced to general or vehicle-specific operational guidance for pilots.

Modeling Natural Tritium in Precipitation and its Dependence on Decadal Solar Activity Variations Using the Atmospheric General Circulation Model MIROC5‐Iso

AbstractModeling tritium content in water presents a meaningful way to evaluate the representation of the water cycle in climate models as it traces fluxes within and between the reservoirs involved in the water cycle (stratosphere, troposphere, and ocean). In this study, we present the implementation of natural tritium in water in the atmospheric general circulation model (AGCM) MIROC5‐iso and its simulation for the period 1979–2018. Owing to recently published tritium production calculations, we were able to investigate, for the first time, the influence of natural tritium production related to the 11‐yr solar cycle on tritium in precipitation. MIROC5‐iso correctly simulates continental, latitudinal, and altitude effects on tritium in precipitation. The seasonal tritium content peaks, linked to stratosphere‐troposphere exchanges, are accurately simulated in terms of timing, even though MIROC5‐iso underestimates the amplitude of the changes. Decadal tritium concentration variations in precipitation owing to the 11‐yr solar cycle are well simulated in MIROC5‐iso, in agreement with the observations at Vostok in Antarctica for example, Finally, our simulations revealed that the internal climate variability plays an important role in tritium in polar precipitation. Owing to its influence on the south polar vortex, the Southern Annular Mode enhances the effect of the production component on tritium in East Antarctic precipitation. In Greenland, we found an east‐west contrast in the detection of the 11‐yr solar cycle in tritium in precipitation owing to the influence of the North Atlantic Oscillation on humidity conditions.

Improved trade-off model of land use functions: Differentiated objective setting by territory spatial planning

Land use functions (LUFs) refer to the capacity of a land use system to supply human welfare; understanding the trade-offs among multiple LUFs to transform land systems for people and nature is pivotal. The traditional way to assess the degree of trade-off between functions based on the level of multiple functions ignores the differences in natural and social conditions for developing ecological, productive, and livelihood functions of land in different regions. That method makes it difficult to achieve effective land use optimization strategies. In this study, an improved framework for identified trade-offs of production-living-ecological function indicator was developed. Based on the national territory spatial planning, we constructed land use multifunctionality trade-offs degree (LUMTD) and analysed the relationship between the indicators. A generalized additive model was also used to explore the natural and human impacts on land use multifunctionality trade-offs. Land use conflicts were found to be more intense in high altitudes and in transition zones between high altitudes. The LUMTD in the plains dominated by classes I and II accounted for 50 % of the total; it was dominated by classes IV and V in the plateau and its transition areas and accounted for more than 50 % of the total. Our results suggest that the influence of natural and socioeconomic factors on LUMTD had a clear threshold, with the threshold effect of altitude on LUMTD beginning to occur within the 1,000 ∼ 2,000 m elevation range, of temperature at 10 °C, and of built-up land density at 1,200. An efficient differentiation strategy for avoiding land use conflict might be collaborative land management actions that focus on the coordinated development of land production, ecological, and living functions.

Does Increasing Haemoglobin At High Altitude Alone Cause A Rise In Coronary Artery Disease; A Prospective Study

Objective: To study the effect of high altitude on haemoglobin concentration with coronary artery disease. Study Design: Prospective longitudinal study. Place and Duration of Study: Combined Military Hospital, Skardu Pakistan, from Jan to Dec 2018 Methodology: All individuals working at high altitudes diagnosed with coronary artery disease (CAD) were included. Haemoglobin concentration was measured by doing a complete blood picture. Results: The total number of patients diagnosed with coronary artery disease in the study was 34 (all males). 16(47%) of the patients with coronary artery disease were evacuated from the height of 8000 to 13000 feet, 16(47%) from the height of 13001 to 18000 feet and 2(6%) patients were evacuated from the height of more than 18000 feet. The mean haemoglobin (Hb) of patients evacuated from the height of 8000 to 13000 feet was 15.7±1.4gm/dl; of patients evacuated from a height of 13001 to 18000 feet was 16.3±1.5gm/dl, and of patients evacuated from more than 18000 feet was 18.3±1.2gm/dl. Conclusion: Persistent rise in haemoglobin was noted with increasing altitude. However, most of the patients with coronary artery disease were from a height of 13000 to 18000 feet.

Altitude-associated trends in bacterial communities in ultrahigh-altitude residences

BackgroundIndoor bacterial communities may change with altitude because their major contributors, outdoor bacterial communities, vary with altitude. People’s health effects from bacteria inhalation exposure can also vary with altitude because human respiratory physiology changes with oxygen content in air. Accordingly, adjusting indoor bacterial communities may help to acclimate newcomers from low-altitude environments to ultrahigh-altitude environments. To lay the groundwork for further research, we aimed to first elucidate the bacterial communities in ultrahigh-altitude residences and the effects of altitude on these communities. We collected 187 environmental samples from residential communities at ultrahigh altitudes of 3811–4651 m in Ngari, China and sequenced bacterial 16S rRNA genes. ResultsOn one hand, when abundant genera in ultrahigh-altitude residences and those reported by previous studies on low-altitude residences were compared, nine genera were shared, whereas other five genera were abundant only at ultrahigh altitudes. On the other hand, when the bacterial communities of residences at different ultrahigh altitudes were further compared, the bacterial composition in indoor surface samples varied significantly with altitude. The relative abundance of five bacterial genera in indoor air samples and 10 genera and three phyla in indoor surface samples varied monotonically with altitude. ConclusionsAltitude may be a long-neglected factor that shapes residential bacterial communities and thus warrants attention.