High-altitude Regions Research Articles

The Disparity in Normalized Difference Vegetarian Index Response to Climate Warming and Humidification in the Tibetan Plateau before and after 1998

The Tibetan Plateau (TP) serves as a crucial ecological barrier in Asia, with vegetation playing a pivotal role in the terrestrial ecosystem by facilitating energy exchange between the land and atmosphere, regulating climate, and participating in the carbon cycle. In this study, we analyze the characteristics of surface vegetation on the TP in the growing season during 1982–2018 using satellite remote sensing data obtained from the National Oceanic and Atmospheric Administration (NOAA) and China Meteorological Forcing Dataset (CMFD). We investigate how these characteristics respond to climate change under different warming and humidification conditions across the TP. The main conclusions are as follows. (1) The normalized difference vegetation index (NDVI) values on the TP exhibit a gradual decrease from southeast to northwest during the growing season. There is a significant overall increasing trend at a climate tendency rate of 0.01·decade−1 (p < 0.01) from 1982 to 2018, characterized by a notable mutation of around 1998. Over the past 37 years, a polarized trend of vegetation was observed on the TP, with notable improvement in its central and eastern regions. However, there has been noticeable degradation in northwestern TP, specifically within the Kunlun Mountains and Qaidam Basin. (2) The climate of the TP demonstrates distinct regional disparities in terms of warming and humidification characteristics before and after 1998. During the period of 1982–1998 (1998–2018), the temperature increase is primarily concentrated in the northern (southern) TP, while precipitation increase is mainly observed in the southern and northwestern (northeastern and western) regions of the TP. (3) The responses of surface vegetation to climate factors exhibit significant variations across diverse climatic backgrounds. It is noteworthy that moisture conditions have a substantial impact on the response of vegetation to air temperature on the TP. During the period of 1982–1998, under relatively insufficient moisture conditions, a positive correlation was observed between air temperature and surface vegetation in the humid and semi-humid regions of the southeastern TP, while a negative correlation was found in the semi-arid regions of northeastern TP. During 1998–2018, as moisture conditions became relatively sufficient, surface vegetation in the semi-arid regions showed positive correlations with both temperature and precipitation. However, surface vegetation in the humid and semi-humid regions exhibited a significant negative correlation with precipitation. During this period, the synergistic effects between warm and humid climates in the semi-arid regions of northeastern TP and warm and dry climates in humid and semi-humid regions of southeastern TP substantially enhanced surface vegetation on the TP. Furthermore, our results indicate that thermal factors (air temperature) primarily influence variations in surface vegetation within the high-altitude arid region of the TP. During 1998–2018, a significant cooling trend was observed in the northwestern TP, which could potentially account for the degradation of surface vegetation in the Kunlun Mountains. The findings of this study establish a scientific basis for the sustainable development of grassland ecosystems on the TP.

Estimates of net primary productivity and actual evapotranspiration over the Tibetan Plateau from the Community Land Model version 4.5 with four atmospheric forcing datasets

Abstract The accuracy of the simulation of carbon and water processes largely relies on the selection of atmospheric forcing datasets when driving land surface models (LSM). Particularly in high-altitude regions, choosing appropriate atmospheric forcing datasets can effectively reduce uncertainties in the LSM simulations. Therefore, this study conducted four offline LSM simulations over the Tibetan Plateau (TP) using the Community Land Model version 4.5 (CLM4.5) driven by four state-of-the-art atmospheric forcing datasets. The performances of CRUNCEP (CLM4.5 model default) and three other reanalysis-based atmospheric forcing datasets (i.e. ITPCAS, GSWP3 and WFDEI) in simulating the net primary productivity (NPP) and actual evapotranspiration (ET) were evaluated based on in situ and gridded reference datasets. Compared with in situ observations, simulated results exhibited determination coefficients (R2) ranging from 0.58 to 0.84 and 0.59 to 0.87 for observed NPP and ET, respectively, among which GSWP3 and ITPCAS showed superior performance. At the plateau level, CRUNCEP-based simulations displayed the largest bias compared with the reference NPP and ET. GSWP3-based simulations demonstrated the best performance when comprehensively considering both the magnitudes and change trends of TP-averaged NPP and ET. The simulated ET increase over the TP during 1982–2010 based on ITPCAS was significantly greater than in the other three simulations and reference ET, suggesting that ITPCAS may not be appropriate for studying long-term ET changes over the TP. These results suggest that GSWP3 is recommended for driving CLM4.5 in conducting long-term carbon and water processes simulations over the TP. This study contributes to enhancing the accuracy of LSM in water–carbon simulations over alpine regions.

Genomics and resequencing of Fagopyrum dibotrys from different geographic regions reveals species evolution and genetic diversity.

Fagopyrum dibotrys, belonging to the family Polygonaceae and genus Fagopyrum, is used in traditional Chinese medicine and is rich in beneficial components, such as flavonoids. As its abundant medicinal value has become increasingly recognized, its excessive development poses a considerable challenge to wild germplasm resources, necessitating artificial cultivation and domestication. Considering these factors, a high-quality genome of F. dibotrys was assembled and the evolutionary relationships within Caryophyllales were compared, based on which 58 individual samples of F. dibotrys were re-sequenced. We found that the samples could be categorized into three purebred populations and regions distributed at distinct elevations. Our varieties were cultivated from the parental populations of the subpopulation in central Yunnan. F. dibotrys is speculated to have originated in the high-altitude Tibetan Plateau region, and that its combination with flavonoids can protect plants against ultraviolet radiation; this infers a subpopulation with a high accumulation of flavonoids. This study assembled a high-quality genome and provided a theoretical foundation for the future introduction, domestication, and development of cultivated varieties of F. dibotrys.

Arthroplasty at Very High Altitude with Restricted Resources: Our Experience and Review of Literature.

Patients living in high altitudes are often deprived of total knee arthroplasty (TKA) due to logistic reasons, economic, and social challenges in performing surgical procedures for management of knee pain. Surgical procedures in high-altitude dwellers have associated risk of deep venous thrombosis/pulmonary embolism (DVT/PE). In patients undergoing these procedures at lower altitudes, return to high altitudes can cause high-altitude pulmonary edema (HAPE). We share our experience of performing TKA in high-altitude dwellers by setting up a surgical camp at 11,000 feet. A retrospective assessment of patients undergoing total knee arthroplasty at a camp set up at 11,000 feet between 2014 and 2020 was undertaken. Follow-up data of patients which included clinical assessment by the Knee Society Score (KSS) and complications like DVT, infection, residual deformity, etc. were included in the study. Radiographic evaluation to look for evidence of implant loosening was also inculcated. 132 patients (202 knee joints in 50 male and 82 female patients) underwent TKA during annual camps. The average follow-up of patients was 60months. Mean pre-operative KSS was 38, which was increased to 83 at 1-year follow-up post-surgery. There was no evidence of DVT or superficial or deep infection in any patient in the post-operative period. With this study, we want to highlight that total knee arthroplasty can be safely performed at high altitudes and remote areas with limited health facilities. We believe it is a safer and more convenient prospect for the residents of high-altitude regions. III.

Geographical altitude and stunting among children aged under 5 years in India

IntroductionPrevious studies have found positive associations between higher geographical altitude and increased risk of stunting in children under 5 years old, but little evidence exists on this relationship in the...

Insights into the morphology, composition, and sources of atmospheric particulate matter on Mount Qomolangma (Everest)

Aerosol category and its physicochemical properties are key factors influencing its climate and environmental effects. To further enhance our understanding of aerosols in the Himalayas-Tibetan Plateau region, atmospheric particulate matter samples were collected at three different altitudes on Mount Qomolangma (Everest). Using an automated scanning electron microscope system, the composition, size, and morphology of 52,349 particles were analyzed. The average mass concentrations of PM1, PM2.5, and PM10 were 0.678, 5.054, and 16.698 µg/m3, respectively. Aluminosilicate particles dominated the samples, accounting for 71.5 % to 82.8 % of PM10 mass and 34.7 % to 62.4 % of the particle number. Quartz particles, carbonate particles, metal oxides, and sulfates were also observed at different periods. Carbonaceous particles made up a significant portion of aerosols, comprising 2.1 % to 9.7 % of PM10 mass and 10.4 % to 45.4 % of particle number, with their concentration showing an upward trend with altitude. Small amounts of tar ball particles and fly ash particles were also observed, providing direct evidence of anthropogenic influences on high-altitude regions, even at altitudes exceeding 6000 m. The size distribution and abundance of different particle categories were closely related to the transport trajectories of air masses. The morphology of different particle categories varied, with fly ash particles mainly spherical and carbonaceous particles exhibiting higher irregularity.

Evolution and stability of bubbles in cement-based materials under low air pressure: A Theoretical and experimental Study

In recent years, more and more infrastructures are being built in high-altitude regions where the atmospheric pressure is lowered. However, low atmospheric pressure affects bubble stability, which deteriorates the frost resistance of concrete and the sustainability of civil infrastructures in high-altitude regions. Currently, the evolution of bubbles in cement-based materials under low air pressure is unclear. Therefore, we developed the bubble dynamic differential equation which considering the viscosity of cement paste to describe bubble evolution and stability in cement-based materials; investigated the effect of nano-bubble water (NBW) on bubble stability in cement-based materials; and revealed the stabilization mechanism of bubbles reinforced by NBW. An experimental apparatus that integrates pressure regulating, bubbling, observation, and data recording is designed. The high-precision microscope and air-void analyzer are employed to study the dynamic evolution of bubble distribution over time and the hardened air-void parameters. The bubble dynamic differential equation indicates that the decrease of initial bubble size can improve bubble stability. The experimental results show that the average bubble diameter at low air pressure (0.5P) is larger than that at standard air pressure (P), and bubbles evolve more rapidly at 0.5P; when NBW is used, the average bubble diameter at P and 0.5P is reduced by 24.5% and 48.8%, respectively, and bubbles evolve more slowly. The stabilization principle of bubbles reinforced by NBW is discussed. It is proved that low atmospheric pressure affects the generation and evolution of bubbles, while NBW can reduce initial bubble size and improve bubble stability in cement-based materials. This research not only establishes bubble dynamic differential equation in cementitious materials, but also proposes an effective approach to improve bubble stability of cement-based materials at low atmospheric pressure, which promotes the sustainable development of infrastructures in high-altitude regions.

Assessment of vitamin D status and associated risk factors in high-altitude populations affected by multiple sclerosis: A case-control study.

Several studies have suggested a correlation between serum vitamin D (VitD) level and multiple sclerosis (MS). MS has a known latitudinal distribution pattern, with greater incidence, prevalence, and mortality rates at higher latitudes. This study aims to assess levels of VitD and serum potassium in subjects with MS and the impact of gender and age as disease risk factors. A cross-sectional case-control study was conducted in a high-altitude region of Saudi Arabia. VitD deficiency was defined as serum 25 (OH)D level of ≤20 ng/mL and insufficiency as a serum level between >20 ng/mL and <30 ng/mL. Two hundred patients with MS volunteered for the study, and 160 healthy participants served as controls. VitD and serum potassium were measured in patients and controls. Student t test and regression analysis were used to analyze the data. The average MS patient age was 37.37 ± 10.8 years. Most (73.02%) MS patients suffered from deficient vitamin D, while insufficiency (20-29 ng/mL) was found in 12.17%. Only 6.35% had sufficient vitamin D (30-40 ng/mL). VitD was significantly decreased in MS patients compared to the healthy controls (17.036 vs 25.01 ng/mL, P < .001), while serum potassium was also decreased (4.278 vs 4.329 mmol/L, P = .269). Risk factors found to have a statistically significant association with MS included female gender (odd ratio [OR] = 1.72, 95% confidence interval: 1.016-2.915; P = .044) and patient age < 40 years (OR = 1.04, 95% confidence interval: 1.023-1.054; P = .044). VitD was significantly lower in MS patients. The prevalence of MS was higher among women and younger individuals in a high-altitude population in Saudi Arabia.

Cold waves and fine particulate matter in high-altitude Chinese cities: assessing their interactive impact on outpatient visits for respiratory disease.

Extreme weather events like heatwaves and fine particulate matter (PM2.5) have a synergistic effect on mortality, but research on the synergistic effect of cold waves and PM2.5 on outpatient visits for respiratory disease, especially at high altitudes in climate change-sensitive areas, is lacking. we collected time-series data on meteorological, air pollution, and outpatient visits for respiratory disease in Xining. We examined the associations between cold waves, PM2.5, and outpatient visits for respiratory disease using a time-stratified case-crossover approach and distributional lag nonlinear modeling. Our analysis also calculated the relative excess odds due to interaction (REOI), proportion attributable to interaction (AP), and synergy index (S). We additionally analyzed cold waves over time to verify climate change. Under different definitions of cold waves, the odds ratio for the correlation between cold waves and outpatient visits for respiratory disease ranged from 0.95 (95% CI: 0.86, 1.05) to 1.58 (1.47, 1.70). Exposure to PM2.5 was significantly associated with an increase in outpatient visits for respiratory disease. We found that cold waves can synergize with PM2.5 to increase outpatient visits for respiratory disease (REOI > 0, AP > 0, S > 1), decreasing with stricter definitions of cold waves and longer durations. Cold waves' independent effect decreased over time, but their interaction effect persisted. From 8.1 to 21.8% of outpatient visits were due to cold waves and high-level PM2.5. People aged 0-14 and ≥ 65 were more susceptible to cold waves and PM2.5, with a significant interaction for those aged 15-64 and ≥ 65. Our study fills the gap on how extreme weather and PM2.5 synergistically affect respiratory disease outpatient visits in high-altitude regions. The synergy of cold waves and PM2.5 increases outpatient visits for respiratory disease, especially in the elderly. Cold wave warnings and PM2.5 reduction have major public health benefits.

Uncovering sources, distribution, and seasonal patterns of trace element deposition: the elemental puzzle of the western Himalayas.

The transport and deposition of atmospheric pollutants in the Himalayas have a adverse impact on the climate, cryosphere, ecosystem, and monsoon patterns. Unfortunately, there is a insufficiency of data on trace element concentrations and behaviors in the high-altitude Himalayan region, leading to limited research in this area. This study presents a comprehensive and detailed comprehension of trace element deposition, its spatial distribution, seasonal variations, and anthropogenic signals in the high-altitude Kashmir region of the Western Himalayas. Our investigation involved the analysis of 10 trace elements (Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb) in glacier ice, snow pits, surface snow, and rainwater collected at various sites including Kolahoi, Thajwas, Pahalgam (Greater Himalayan ranges), and Kongdori and Shopian (Pir Panjal Ranges) during 2021.The study reveals distinct ranges of concentrations for the trace elements at different sampling sites. Our analysis of trace element concentration depth profiles in snow pits reveals seasonal fluctuations during the deposition year. The highest concentrations were found in the autumn(below 20cm) and summer (top layer), compared to the winter concentration (10-20cm). The high enrichment factors (EFs) suggest the severity of human-induced trace metal deposition in the western Himalayan region, relative to surrounding regions. Surprisingly, the concentrations and EFs of trace elements showed seasonal contradictions, with lower concentration values and higher EFs during the non-monsoon season and vice versa. A source apportionment analysis using the positive matrix factorization (PMF) technique identified five sources of trace element deposition in the region, including crustal sources (32.33%), coal combustion (15.62%), biomass burning (17.63%), traffic emission (18.8%), and industrial sources (15.6%). Additionally, the study incorporated backward trajectories coupled with δ18O using the NOAA HYSPLIT model to estimate moisture sources in the region, which suggests atmospheric pollutants predominately deposited from the large-scale atmospheric circulation from westerlies (75%) during non-monsoon season. These findings underscore the urgent need for enhanced monitoring and research efforts in the future.

Refined Analysis of Vegetation Phenology Changes and Driving Forces in High Latitude Altitude Regions of the Northern Hemisphere: Insights from High Temporal Resolution MODIS Products

The vegetation patterns in high-latitude and high-altitude regions (HLAR) of the Northern Hemisphere are undergoing significant changes due to the combined effects of global warming and human activities, leading to increased uncertainties in vegetation phenological assessment. However, previous studies on vegetation phenological changes often relied on long-term time series of remote sensing products for evaluation and lacked comprehensive analysis of driving factors. In this study, we utilized high temporal resolution seamless MODIS products (MODIS-NDVISDC and MODIS-EVI2SDC) to assess the vegetation phenological changes in High-Latitude-Altitude Regions (HLAR) of the Northern Hemisphere. We quantified the differences in vegetation phenology among different land-use types and determined the main driving factors behind vegetation phenological changes. The results showed that the length of the growing season (LOS) derived from MODIS-NDVISDC was 8.9 days longer than that derived from MODIS-EVI2SDC, with an earlier start of the growing season (SOS) by 1.5 days and a later end of the growing season (EOS) by 7.4 days. Among different vegetation types, deciduous needleleaf forests exhibited the fastest LOS extension (p &lt; 0.01), while croplands showed the fastest LOS reduction (p &lt; 0.05). Regarding land-use transitions, the conversion of built-up land to forest and grassland had the longest LOS. In expanding agricultural areas, the LOS of land converted from built-up land to cropland was significantly higher than that of other land conversions. We analyzed human activities and found that as the human footprint gradient increased, the LOS showed a decreasing trend. Among the climate-related factors, the dominant response of phenology to temperature was the strongest in the vegetation greening period. During the vegetation browning period, the temperature control was weakened, and the control of radiation and precipitation was enhanced, accounting for 20–30% of the area, respectively. Finally, we supplement and prove that the highest contributions to vegetation greening in the Northern Hemisphere occurred during the SOS period (May–June) and the EOS period (October). Our study provides a theoretical basis for vegetation phenological assessment under global change. It also offers new insights for land resource management and planning in high-latitude and high-altitude regions.

Future Projections of Precipitation Extremes for Greece Based on an Ensemble of High-Resolution Regional Climate Model Simulations

An assessment of the projected changes in precipitation extremes for the 21st century is presented here for Greece and its individual administrative regions. The analysis relies on an ensemble of high-resolution Regional Climate Model (RCM) simulations following various Representative Concentration Pathways (RCP2.6, RCP4.5, and RCP8.5). The simulated changes in future annual total precipitation (PRTOT) under the examined scenarios are generally negative but statistically non-robust, except towards the end of the century (2071–2100) over high-altitude mountainous regions in Western Greece, Peloponnese, and Crete under RCP8.5. The pattern of change in the number of very heavy precipitation days (R20) is linked to the respective pattern of the PRTOT change with a statistically robust decrease of up to −5 days per year only over parts of the high-altitude mountainous regions in Western Greece, Peloponnese, and Crete for 2071–2100 under RCP8.5. Contrasting the future tendency for decrease in total precipitation and R20, the changes in the intensity of precipitation extremes show a tendency for intensification. However, these change patterns are non-robust for all periods and scenarios. Statistical significance is indicated for the highest 1-day precipitation amount in a year (Rx1day) for the administrative regions of Thessaly, Central Greece, Ionian Islands, and North Aegean under RCP8.5 in 2071–2100. The changes in the contribution of the wettest day per year to the annual total precipitation (RxTratio) are mainly positive but non-robust for most of Greece and all scenarios in the period 2021–2050, becoming more positive and robust in 2071–2100 for RCP8.5. This work highlights the necessity of taking into consideration high-resolution multi-model RCM estimates in future precipitation extremes with various scenarios, for assessing their potential impact on flood episodes and the strategic planning of structure resilience at national and regional level under the anticipated human-induced future climate change.

Novel insight into the genetic signatures of altitude adaptation related body composition in Tibetans.

The Tibetan population residing in high-altitude (HA) regions has adapted to extreme hypoxic environments. However, there is limited understanding of the genetic basis of body compositions in Tibetan population adapted to HA. We performed a genome-wide association study (GWAS) to identify genetic variants associated with HA and HA-related body composition traits. A total of 755,731 single nucleotide polymorphisms (SNPs) were genotyped using the precision medicine diversity array from 996 Tibetan college students. T-tests and Pearson correlation analysis were used to estimate the association between body compositions and altitude. The mixed linear regression identified the SNPs significantly associated with HA and HA-related body compositions. LASSO regression was used to screen for important SNPs in HA and body compositions. Significant differences were observed in lean body mass (LBW), muscle mass (MM), total body water (TBW), standard weight (SBW), basal metabolic rate (BMR), total protein (TP), and total inorganic salt (Is) in different altitudes stratification. We identified three SNPs in EPAS1 (rs1562453, rs7589621 and rs7583392) that were significantly associated with HA (p < 5 × 10-7). GWAS analysis of 7 HA-related body composition traits, we identified 14 SNPs for LBM, 11 SNPs for TBW, 15 SNPs for MM, 16 SNPs for SBW, 9 SNPs for BMR, 12 SNPs for TP, and 26 SNPs for Is (p < 5.0 × 10-5). These findings provide insight into the genetic basis of body composition in Tibetan college students adapted to HA, and lay the foundation for further investigation into the molecular mechanisms underlying HA adaptation.

Does climate shape geographical morphological variation of spines in Neotropical spiny rats (Rodentia, Echimyidae, Trinomys)?

Abstract Flattened and flexible spiny hairs, the aristiforms, evolved independently in some lineages of rodents, but unlikely capable of causing severe damage to predators. Their biological roles are not yet clearly known and some different thermoregulatory functions have been proposed, often associated with severe climatic conditions but not yet tested. In this study we investigated whether climate may be a major factor shaping geographic variation of length and width of aristiform hairs of 2 species of Neotropical spiny rats of the genus Trinomys (Echimyidae) occurring in eastern Brazil: T. albispinus and T. setosus. Results revealed clinal variation in these hairs. While bioclimatic factors and geographic distance together accounted for up to a third of the morphometric variation, the exclusive impact of climate was limited, explaining only up to 3% of the observed variation. However, considering the close association between climate and geographic distance, the role of climate in shaping aristiform hair cannot be discounted. While our results did not fully support the hypothesis that well-developed, wide spiny hairs are selected for greater protection against rain for underhairs, they marginally supported their role in facilitating heat loss in warm environments by facilitating water condensation. More consistently, results show that narrow spiny hairs tended to evolve in cold environments, likely enhancing thermal insulation. The length of aristiform hair in T. albispinus also appeared to respond to this function, becoming longer in cold and high-altitude regions. However, we cannot rule out the possibility of an evolutionary response correlated with selection on underhairs. Future experimental studies should test the thermoregulatory function of flexible spiny hairs and investigate the geographic variation of these structures in other rodent species.

Effect of foaming characteristics of air entrained agents on mechanical properties and pore structures of cement-based materials in plateau mountainous regions

Concrete freeze-thaw damage is common in high-altitude regions. Adding an appropriate amount of air-entraining agents (AEA) can improve the flowability of fresh concrete and the frost resistance of hardened concrete, without significantly affecting concrete strength. However, the existing studies of the influence and mechanism of AEAs on concrete mainly focus on conventional environmental tests and simulated conditions, with less consideration to the various environmental factors caused by real altitude changes. In this study, five types of AEAs are utilized according to bubble shaking tests in two different altitude environments: Chengdu, Sichuan (altitude: 300 m; air pressure: 96.7 kPa), and Aba Prefecture, Sichuan (altitude: 3700 m; air pressure: 66.7 kPa). Physical and mechanical properties as well as pore structure tests are also conducted on AEA paste and concrete. The results show that the relationship between air bubble sizes and surface tension of AEA solutions is the closest, with larger bubble sizes, smaller bubble volumes, and poorer foaming properties observed at high-altitude regions. Adding an appropriate amount of AEA can improve concrete workability. In high-altitude and low-temperature regions, AEA concrete exhibits better slump retention. The addition of triterpenoid saponin AEA increases the proportion of small pores (0.5 μm–200 μm) in paste and concrete, with a lower growth rate observed at high altitudes compared to lower altitudes. Additionally, the average pore diameter and bubble spacing coefficient of hardened paste decrease, optimizing the pore structure. Triterpenoid saponin AEA is recommended for improving concrete performance in high-altitude environments, with a recommended dosage of 0.01 %.

Soil microbial community responses to long-term experimental warming in an alpine Dryas octopetala heath in Norway

Over the last century, high-altitude and high-latitude regions have experienced global warming at rates higher than the worldwide average. Climate change influences complex soil-microbe-plant-atmosphere interactions, leading to changes in plant-associated soil microbial diversity and functioning and alterations in nutrient cycling, carbon fluxes, and storage. This study analyzed how two decades of global warming simulated by open-top chambers (OTCs) affected soil bacterial and fungal communities in an alpine dwarf-shrub heath dominated by Dryas octopetala in Norway. We collected soil samples from 10 OTCs and 10 control plots and compared their physicochemical properties, microbial biomass, extracellular enzyme activities, and bacterial and fungal community diversity and composition. Warming did not significantly affect the bacterial community despite the tendency to reduce alpha diversity and increase the degree of specialisation. In contrast, two decades of warming significantly affected fungal community composition, which was dominated by ectomycorrhizal Basidiomycota. While there was no significant effect on the total fungal community diversity, a significant shift in saprotrophic Ascomycota taxa was observed between the warmed and control plots. Their positive correlations with oxidative enzymes and fungal biomass suggest that long-term warming might lead to an increase in fungal biomass and the activity of oxidative enzymes, promoting the decomposition of more recalcitrant biopolymers. This may result in an increase in CO2 flux into the atmosphere and a decrease in ecosystem C storage.

Assessment of Black Carbon, optical properties and aerosol radiative forcing at Pranmati basin Himalayan critical zone observatory

The study aimed to understand the optical properties of Black Carbon (BC) and radiative forcing over a data deficient Himalayan region focusing on critical zone observatory employing ground-based measurements by Aethalometer for BC and satellite retrieval techniques for optical properties during mid-May-June 2022 and January–May 2023.BC mass concentration ranged from 0.18 to 4.43 μgm−3, exhibit a mean of 1.47 ± 0.83 μgm−3 with higher summer concentration (1.51 ± 0.94 μgm−3) than winter (1.39 ± 0.61 μgm−3). The average Absorption Ångström Exponent observed to be significantly higher than unity (1.77 ± 0.31) over the studied high-altitude Himalayan region, suggesting the dominance of biomass-burning aerosol. Higher aethalometer derived compensation parameter (K) in winter suggesting locally originated BC while, lower K value in summer suggesting aged BC transported from Indo-Gangetic Plains.Optical properties calculated from “Optical Properties of Aerosol and Cloud” (OPAC) model are used in the “Santa Barbara DISORT Atmospheric Radiative Transfer” (SBDART) model to calculate the aerosol Direct Radiative Force (DRF). The entire studied period is characterized by the predominance of absorbing aerosols, particularly BC, increasing Aerosol Optical Depth, Asymmetric Parameters and decreasing Single Scattering Albedo, leading to a considerable increase in atmospheric radiative forcing (+0.9 Wm−2, top of atmosphere) and Heating Rate (0.36 KDay−1). The mean radiative forcing within atmosphere during summer was higher (+14.29 Wm−2) relative to the winter (+12.00 Wm−2), emphasizing the impact of absorbing aerosols on regional warming and potential glacier melting in the Himalayas at a faster rate. Urgent policy consideration for the reduction of absorbing aerosols is highlighted, recognizing the critical roles of Black Carbon in the changing behaviour of Critical Zone observatory. The study's data serve as a valuable resource to understanding and addressing uncertainties in climate models, aiding effective policy implementation for Black Carbon reduction.

First photographic record of the snow leopard Panthera uncia in Kishtwar High Altitude National Park, Jammu and Kashmir, India

Abstract The snow leopard Panthera uncia is categorized as Vulnerable on the IUCN Red List. It is the least well-known of the large felids because of its shy and elusive nature and the inaccessible terrain it inhabits across the mountains of Central and South Asia. We report the first photographic record of the snow leopard in Kishtwar High Altitude National Park, India. During our camera-trapping surveys, conducted using a grid-based design, we obtained eight photographs of snow leopards, the first at 3,280 m altitude on 19 September 2022 and subsequent photographs over 3,004–3,878 m altitude. We identified at least four different individuals, establishing the species’ occurrence in Kiyar, Nanth and Renai catchments, with a capture rate of 0.123 ± SE 0.072 captures/100 trap-nights. We also recorded the presence of snow leopard prey species, including the Siberian ibex Capra sibirica, Himalayan musk deer Moschus leucogaster, long-tailed marmot Marmota caudata and pika Ochotona sp., identifying the area as potential snow leopard habitat. Given the location of Kishtwar High Altitude National Park, this record is significant for the overall snow leopard conservation landscape in India. We recommend a comprehensive study across the Kishtwar landscape to assess the occupancy, abundance, demography and movement patterns of the snow leopard and its prey. In addition, interactions between the snow leopard and pastoral communities should be assessed to understand the challenges facing the conservation and management of this important high-altitude region.

Study on the physical and mechanical properties of recycled weathered rock materials in expressway subgrade in permafrost areas

In view of the specialized climatic conditions in high-cold and high-altitude regions, the direct, repeated freeze-thaw and freezing processes resulting from diurnal and seasonal temperature changes pose a significant threat to the integrity of the roadbed stones in these areas. Weathering and fragmentation constitute a form of rock damage. Rock damage negatively impacts the air convection within the rock subgrade, rendering it incapable of safeguarding frozen soil. The objective of this study is to investigate the mechanical properties and the constitutive model for freeze-thaw damage of three recycled weathered rock materials subjected to varying freeze-thaw cycles. Additionally, it aims to examine the damage and degradation mechanism of recycled weathered rock materials under the combined influence of freeze-thaw and load. The model is then employed to validate the experimental data. Research indicates that with an increase in the number of freeze-thaw cycles, the quality of the three types of recycled weathered rock samples exhibits a gradual decrease, accompanied by a corresponding reduction in P-wave speed. The elastic modulus and compressive strength of the three recycled weathered rock materials show an increase with rising confining pressure and a decrease with a growing number of freeze-thaw cycles. The types of damage include splitting and shear damage. The presented damage model can elucidate the pattern of damage evolution in the specimen under varying confining pressures and freeze-thaw cycles. The expansion of internal micro-cracks is influenced differently by freeze-thaw cycles and loads; moreover, the coupling effect of damage exhibits pronounced nonlinear characteristics. Substantiated by experimental results, the damage constitutive model demonstrates both reasonability and feasibility.

Elucidation of the Role of TRPV1, VEGF-A, TXA2, Redox Homeostasis, and Inflammatory Cascades in Protection against Cold Injuries by Herbosomal-Loaded PEG-Poloxamer Topical Formulation.

High-altitude regions, cold deserts, permafrost regions, and the polar region have some of the severest cold conditions on earth and pose immense perils of cold injuries to exposed individuals. Accidental and unintended exposures to severe cold, either unintentionally or due to occupational risks, can greatly increase the risk of serious conditions including hypothermia, trench foot, and cold injuries like frostbite. Cold-induced vasoconstriction and intracellular/intravascular ice crystal formation lead to hypoxic conditions at the cellular level. The condition is exacerbated in individuals having inadequate and proper covering and layering, particularly when large area of the body are exposed to extremely cold environments. There is a paucity of preventive and therapeutic pharmacological modalities that have been explored for managing and treating cold injuries. Given this, an efficient modality that can potentiate the healing of frostbite was investigated by studying various complex pathophysiological changes that occur during severe cold injuries. In the current research, we report the effectiveness and healing properties of a standardized formulation, i.e., a herbosomal-loaded PEG-poloxamer topical formulation (n-HPTF), on frostbite. The intricate mechanistic pathways modulated by the novel formulation have been elucidated by studying the pathophysiological sequelae that occur following severe cold exposures leading to frostbite. The results indicate that n-HPTF ameliorates the outcome of frostbite, as it activates positive sensory nerves widely distributed in the epidermis transient receptor potential vanilloid 1 (TRPV1), significantly (p < 0.05) upregulates cytokeratin-14, promotes angiogenesis (VEGF-A), prominently represses the expression of thromboxane formation (TXA2), and significantly (p < 0.05) restores levels of enzymatic (glutathione reductase, superoxide dismutase, and catalase) and nonenzymatic antioxidants (glutathione). Additionally, n-HPTF attenuates oxidative stress and the expression of inflammatory proteins PGF-2α, NFκB-p65, TNF-α, IL-6, IL-1β, malondialdehyde (MDA), advanced oxidative protein products (AOPP), and protein carbonylation (PCO). Masson's Trichrome staining showed that n-HPTF stimulates cellular proliferation, and increases collagen fiber deposition, which significantly (p < 0.05) promotes the healing of frostbitten tissue, as compared to control. We conclude that protection against severe cold injuries by n-HPTF is mediated via modulation of pathways involving TRPV1, VEGF-A, TXA2, redox homeostasis, and inflammatory cascades. The study is likely to have widespread implications for the prophylaxis and management of moderate-to-severe frostbite conditions.