Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 467
Filtrar
1.
Sci Total Environ ; 953: 176179, 2024 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-39260491

RESUMO

Mountainous regions are vital biodiversity hotspots with high heterogeneity, providing essential refugia for vegetation. However, climate change threatens this diversity with the potential homogenization of the distinct environmental conditions at different elevations. Here, we used a time-series (1985-2023) of Normalized Difference Vegetation Index (NDVI) from Landsat archives (30 m) to quantify vegetation changes across an elevation gradient on Himalaya Mountain. Our analysis revealed that over the past 40 years, the Himalayas have experienced widespread greening, accompanied by homogenization of vegetation across elevations. This homogenization, characterized by a reduction in the differences between high and low elevations, can be attributed to two main factors: (1) increased warming and a higher snowmelt rate at high elevations, facilitating rapid changes in high-elevation vegetation activities; and (2) higher anthropogenic disturbance at low and mid elevations, thus inhibiting low-elevation vegetation. These factors have resulted in a reduction of habitat differentiation along the mountain slopes, homogenizing vegetation and potentially threatening the unique biodiversity adapted to specific elevational zones. Our findings emphasize the urgent need for conservation strategies that prioritize the protection of heterogeneous mountain habitats to preserve their rich biodiversity in the face of climate change.


Assuntos
Altitude , Biodiversidade , Mudança Climática , Ecossistema , Monitoramento Ambiental , Plantas , Conservação dos Recursos Naturais , Desenvolvimento Vegetal
2.
Sci Total Environ ; 954: 176180, 2024 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-39270860

RESUMO

Aufeis - a phenomenon associated with permafrost and the cold arid region of Ladakh - serves as a critical water resource for local communities. In several tributaries of the Indus River, aufeis accumulation is enhanced in ice reservoirs (commonly known as "artificial glaciers") to store winter baseflow for crop irrigation during the water-scarce period in spring. This study investigates aufeis thickness and volume across four study sites in the Trans-Himalaya of Central Ladakh: the ice reservoirs of Phuktse and Igoo and the catchments of Gya and Sasoma, where natural aufeis fields occur. Aufeis thickness and volume estimates were derived via differencing of digital elevation models calculated from very high-resolution stereo Pléiades imagery and terrestrial photographs. The study revealed ice thickness up to a maximum of 3 m and could further demonstrate the amplification effect of the walls of the ice reservoirs on aufeis accumulation in both, differenced elevation from Pléiades and terrestrial photographs. Aufeis volumes across the four study sites range from 34,106 ± 13,440 m3 in Phuktse up to 105,790 ± 28,511 m3 in Sasoma, indicating substantial amounts that need to be considered in future hydrological studies in the region. While the approach with terrestrial photographs is especially suitable for local studies, the results from very high-resolution stereo satellite data are promising for aufeis studies on large spatial scales. It represents an important contribution for the understanding of spatial aufeis patterns in the Trans-Himalaya and affected regions worldwide.

3.
Ther Adv Med Oncol ; 16: 17588359241274625, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39301138

RESUMO

Background: The HIMALAYA trial found that durvalumab plus tremelimumab significantly prolonged progression-free survival and overall survival in patients with unresectable hepatocellular carcinoma (HCC) compared with sorafenib. Objective: This study aimed to investigate the cost-effectiveness of durvalumab plus tremelimumab compared with sorafenib in the first-line HCC setting. Design: A Markov model-based cost-effectiveness analysis. Methods: We created a Markov model to compare healthcare costs and clinical outcomes of HCC patients treated with durvalumab plus tremelimumab in the first-line setting compared with sorafenib. We estimated transition probabilities from randomized trials. Lifetime direct healthcare costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios were calculated for first-line durvalumab plus tremelimumab compared with sorafenib from a US payer's perspective. Results: In the base case, first-line durvalumab plus tremelimumab was associated with an improvement of 0.29 QALYs compared with sorafenib. While both treatment strategies were associated with considerable lifetime expenditures, first-line durvalumab plus tremelimumab was less expensive than sorafenib ($188,405 vs $218,584). The incremental net monetary benefit for durvalumab plus tremelimumab versus sorafenib was $72,762 (valuing QALYs at $150,000 each). The results of durvalumab plus tremelimumab were better in terms of costs and health outcomes in patients with HBV-related HCC and high alpha-fetoprotein levels. Conclusion: First-line durvalumab plus tremelimumab was estimated to be dominant for the treatment of unresectable HCC compared with sorafenib from a US payer's perspective.

4.
Indian J Microbiol ; 64(3): 1099-1109, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39282167

RESUMO

Hot springs have tremendous significance due to their divulging physiochemical features. In the recent past, metagenomics has emerged as a unique methodology to explore microbiota as well as new biocatalysts possessing advantageous biochemical properties from hot springs. In the present study, metagenomics has been employed for microbial diversity exploration and identification of genes involved in various metabolic pathways among two hot springs, Manikaran and Tatapani, located in Himachal Pradesh, India. Taxonomic analysis of both metagenomes revealed the dominance of the Proteobacteria phylum. Genomic signatures of other bacterial phyla such as Chloroflexi, Actinobacteria, Bacteroidetes, Cyanobacteria, Planctomycetes, and Firmicutes were also found in significant abundance in both the metagenomes. The abundance of microorganisms belonging to genera, especially Nitrospira, Thauera, Meiothermus, Thiobacillus, Massilia, and Anaerolinea, was reported to be prevalent in the hot springs. A significant amount of metagenomic data remained taxonomically unclassified, which indeed emphasizes the scientific importance of these thermoaquatic niches. The functional potential analysis of both metagenomes revealed pathways related to carbohydrate metabolism, followed by amino acid metabolism, energy metabolism, genetic information processing, metabolism of cofactors and vitamins, membrane transporter, and signal transduction. Exploration of biomass-modifying biocatalysts enumerated the presence of glycoside hydrolases, glycosyl transferases, polysaccharide lyases, and carbohydrate esterases in the metagenomic data. Together, these findings offer an in-depth understanding of the microbial inhabitants in North-Western Himalayan hot springs and their underlying potential for various biotechnological and industrial applications. Supplementary Information: The online version contains supplementary material available at 10.1007/s12088-024-01248-z.

5.
Plant Divers ; 46(5): 600-610, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39290885

RESUMO

The common walnut (Juglans regia) is one of the most economically important nut trees cultivated worldwide. Despite its importance, no comprehensive evaluation of walnut tree population genetics has been undertaken across the range where it originated, Central Asia. In this study, we investigated the genetic diversity and population structure of 1082 individuals from 46 populations across Central Asia. We found moderate genetic diversity of J. regia across Central Asia, with 46 populations clustered into three groups with a weak relationship between genetic and geographic distance. Our findings reveal that the western Himalaya might be the core region of common walnut genetic diversity in Central Asia and that, except for two populations in Gongliu Wild Walnut Valley, humans might have introduced walnut populations to Xinjiang, China. The observed distribution of the genetic landscape has probably been affected by historical climate fluctuation, breeding system, and prolonged anthropogenic activity. We propose the conservation of the core genetic diversity resources in the western Himalaya and pay special attention to populations from Gongliu in Xinjiang. These findings enhance our understanding of the genetic variation throughout the distribution range of J. regia in Central Asia, which will provide a key prerequisite for evidence-based conservation and management.

6.
Zookeys ; 1210: 229-246, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39228389

RESUMO

Recent phylogenetic studies in Himalayan lazy toads of the genus Scutiger Theobald, 1868 revealed the presence of genetically deeply divergent lineages. The taxonomy of S.nepalensis sensu lato was re-assessed based on museum material considering molecular and morphological data. The results strongly support the recognition of a new species, S.kanjiroba sp. nov. distributed along the Nepalese Kanjiroba massif. It is further shown that S.sikimmensis has an apparently much more restricted distribution range than previously thought. The frequent misidentification of Scutiger across large areas of the Himalaya-Tibet area highlights the significance of careful taxonomic evaluation of collection material and the need for the direct morphological comparison of closely related species when describing new species.

7.
Physiol Behav ; 287: 114663, 2024 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-39128618

RESUMO

INTRODUCTION: This study aimed to investigate the effects of normobaric hypoxia (NH) and hypobaric hypoxia (HH) on associative memory performance for emotionally valenced stimuli. METHODS: Two experiments were conducted. In Study 1, n = 18 undergraduates performed an associative memory task under three NH conditions (FiO2= 20.9 %, 15.1 %, 13.6 %) using a tent with a hypoxic generator. In Study 2, n = 20 participants were assessed in a field study at various altitudes on the Himalayan mountains, including the Pyramid Laboratory (5000 m above sea level), using functional Near-Infrared Spectroscopy (fNIRS) and behavioral assessments. RESULTS: Study 1 revealed no significant differences in recognition accuracy across NH conditions. However, Study 2 showed a complex relationship between altitude and memory for emotionally valenced stimuli. At lower altitudes, participants more accurately recognized emotional stimuli compared to neutral ones, a trend that reversed at higher altitudes. Brain oxygenation varied with altitude, indicating adaptive cognitive processing, as revealed by fNIRS measurements. CONCLUSIONS: These findings suggest that hypoxia affects associative memory and emotional processing in an altitude-dependent manner, highlighting adaptive cognitive mechanisms. Understanding the effects of hypobaric hypoxia on cognition and memory can help develop strategies to mitigate its impact in high-altitude and hypoxic environments.

8.
Environ Sci Pollut Res Int ; 31(39): 52326-52351, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39145905

RESUMO

Though climate change and its adverse ecological and geohydrological impacts are being experienced across the world in all types of ecosystems but as far as the Himalaya mountain ecosystem is concerned, the rate of climate change and subsequent impacts have reached an alarming stage due to anthropogenic and technogenic intervention on natural process and now need most effective and less time taking management strategy. Addressing this burning environmental problem, a geospatial artificial intelligence (GeoAI) technique-based case study is presented here from one of the most densely populated and urbanized regions of Himalaya mountain, viz Uttarakhand Himalaya, which is also called central Himalaya. The results of the study suggest that due to quite a high rate of climate change, the climatic zones shifting towards higher altitudes at the average rate of 5.6 2 m/year, causing several adverse ecological impacts in terms of decreasing quality dense temperate forest cover (0.05%/year), snow cover (0.02%/year), water bodies (0.01%/year), agricultural land (0.31%/year), and horticultural land (0.01%/year). Conversion of these eco-friendly land use land cover into barren land, fallow land, and built-up land causes geohydrological consequences of climate change in terms of decreasing rainy days (1%/year), drying perennial springs (0.20%/year), perennial streams (0.11%/year), decreasing spring and stream discharge during non-monsoon season, increased extreme rainfall events (6-8%/year), and subsequent surface runoff during monsoon season. Further, the study advocates that the degraded geohydrological process has resulted in an increased frequency of disaster events (floods, cloudbursts, landslides. etc.) with a 3% (12 events) annual rate, causing great loss of environment, infrastructure, lives, and economy each year. Therefore, it has been very urgent to mitigate climate change and increase geohydrological disaster events through an integrated approach. Keep in view this, the present study proposed an integrated watershed management plan which is equally useful to be implemented across the Himalaya region and other similar ecosystems across the world.


Assuntos
Mudança Climática , Ecossistema , Monitoramento Ambiental , Hidrologia , Índia , Inteligência Artificial
9.
Chem Biodivers ; : e202401756, 2024 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-39146235

RESUMO

Diploknema butyracea (Roxb) H.J Lam, also referred as " Kalpavriksha", is commonly known as Gophal, Cheura, or Indian butter tree. It is a deciduous tree with straight trunks of 15-20m in height and white-yellow-coloured fragile flowers with fragrance, found at altitudes of 300-1500 m in the sub-Himalayan region of India, China, Nepal, and Bhutan. Diploknema have 11 taxa and 8 species, out of which 3 species are found in Uttarakhand hills, Sikkim, Darjeeling, Arunachal Pradesh, and Assam. The tree holds significant economic importance, serving various purposes within ethnic communities. Its high lipid content makes it valuable for food, medicine, construction, and the production of various value-added products. The ethno-pharmacological applications encompass treating rheumatism, burns, asthma, and skin conditions. The plant's different components-bark, leaves, flowers, seeds, and fruits-contain  diverse array of phytoconstituents, including alkaloids, tannins, flavonoids, steroids, terpenoids, and palmitic acid, along with essential nutrients like sodium, calcium, potassium, iron, magnesium, zinc, and various sugars which shows diverse pharmacological and therapeutic activities. Beyond traditional uses, Diploknema is important for diverse industrial application in pharmaceuticals, confectionery, nutraceuticals, and cosmetics. Present paper is an attempt to understand comprehensive details on different aspects of this plant to explore new avenues for various value-added products.

10.
J Ethnobiol Ethnomed ; 20(1): 77, 2024 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-39155383

RESUMO

BACKGROUND: Wild food plants (WFPs) play an important role in the traditional dietary habits of various indigenous communities worldwide, particularly in mountainous regions. To understand the dynamics of food preferences, cross-cultural studies on food plants should be conducted across diverse ethnic groups in a given area. In this context, the current study investigated the use of WFPs by seven different cultural groups in the Kashmir Himalayan Region. In this area, people gather wild plants and their parts for direct consumption, traditional foods, or sale in local markets. Despite this reliance, documentation of the food system, especially concerning WFPs, is notably lacking. Hence, our research aimed to document WFPs, along with associated traditional ecological knowledge, and identify major threats to their long-term sustainability in Division Muzaffarabad. METHODS: Through a comprehensive approach involving questionnaires, interviews, focus groups, and market surveys, we gathered data from 321 respondents. PCA was performed to analyze threats and plant use using "factoextra" in R software. Origin Pro was used to create a chord diagram, while R software was used to generate a Polar heat map. Additionally, a Venn diagram was created using Bioinformatics software. RESULTS: The study included 321 informants, of whom 75.38% were men and 24.61% were women. In total, 113 plant taxa from 74 genera and 41 botanical families were reported. Polygonaceae and Rosaceae accounted for the majority (17 species each), followed by Lamiaceae (7 species). Leaves were the most used part as food sources (41.04%), followed by fruits (33.33%). Most of the species are consumed as cooked (46.46%) and as raw snacks (37.80%). A total of 47 plant species were collected and cooked as wild vegetables, followed by 40 species used as fruits. This study is the first to describe the market potential and ecological distribution of WFPs in the study area. Cross-comparison showed that utilization of WFPs varies significantly across the region and communities, including their edible parts and mode of consumption. Jaccard index (JI) value ranged from 5.81 to 25. Furthermore, the current study describes 29 WFPs and 10 traditional food dishes that have rarely been documented in Pakistan's ethnobotanical literature. Climate change, invasive species, expansion of agriculture, and plant diseases are some of the most significant threats to WFPs in the study area. CONCLUSIONS: The older age group has more knowledge about WFPs compared to the younger generation, who are not interested in learning about the utilization of WFPs. This lack of interest in information about WFPs among the younger generation can be attributed to their limited access to markets and availability of food plants in the study area. Traditional gathering of food plants has been reduced in younger generations during recent years; therefore, it is crucial to develop effective conservation strategies. These efforts not only safeguard indigenous flora, food knowledge, and cultural heritage, but they also contribute to food security and public health by utilizing local wild foods in the examined area.


Assuntos
Segurança Alimentar , Plantas Comestíveis , Humanos , Feminino , Masculino , Índia , Adulto , Pessoa de Meia-Idade , Comparação Transcultural , Etnobotânica , Conhecimento , Adulto Jovem , Idoso , Ecologia
11.
Heliyon ; 10(15): e35275, 2024 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-39166008

RESUMO

Genus Swertia under the family Gentianaceae is morphologically and taxonomically distinct with about 14 species from Sikkim Himalayan region. A Chrono-spatial floral phenology study was conducted on Swertia bimaculata from 1580 to 2400 m altitude in West Sikkim Himalayan region. The floral phenology was studied in a field nursery at 1200 m altitude and spatial floral phenology was studied over a 1580-2400 m altitudinal range in the West Sikkim Himalayan region. Detailed study on flowering pattern and seed formation in S. bimaculata revealed late flowering at 1200 m compared to 2400 m. Plants at the lower altitude showed prolonged and variable flowering from September to November and seed formation from November to December. During September to mid-October, pentamerous and bisexual flowers were observed, followed by 9-16 % tetramerous until November; and up to 24 % trimerous and 10 % bimerous until the end of flowering season in December. By the end of December, 43 % of flowers become stamen-less (monoclinous). Less than 2 % seed formation was observed in stamen-less flowers. The temporal phenological behavior reveals a successful reproductive adaptive strategy, depicting pentamerous flowers during favorable conditions, reducing to tetramerous, followed by tri- & bimerous with female (monoclinous) flowers until the end of flowering with stressful conditions, suggesting its suitability as a stress indicator to the changing climatic conditions. Along the altitudinal range floral anomalies from the usually observed pentamerous (and very rare hexamerous) flowers in favorable conditions change to tetramerous and/or trimerous, as the environmental conditions become more stressful, suggesting that the changes in this species could be used as an indicator of stress in changing climatic conditions.

12.
J Contam Hydrol ; 266: 104411, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39153396

RESUMO

The co-occurrence of microplastics (MPs) and heavy metals in aquatic systems has raised significant concerns, yet their relationship in freshwater ecosystems remains poorly understood. This study aims to evaluate the prevalence of MPs and factors controlling their distribution in both water and sediment in the Markanda River, Northwest India. MPs were extracted from sediment and water samples using density separation and classified through fluorescence microscopy and Raman spectroscopy. Metal concentrations in river water samples were analyzed using ICP-MS, and their correlation with MP abundance was explored. The results indicated the widespread occurrence of MP pollution across the Markanda River basin, with particle concentrations ranging from 10 to 530 particles L-1 in surface water and 1330-4330 particles kg-1 dry weight (dw) in sediment samples. The variability in MP abundance at sampling sites along the Markanda River courses results from factors such as the proximity of industrial establishments and human habitation, while the influence of grain size on MP distribution appears to be limited. Pellets (88.5 %) and fragments (8.5 %) were the most abundant types of MPs, with polyethylene (45.45 %) and polystyrene (30.9 %) being the dominant forms in water samples. The ICP-MS analysis of heavy metals in water samples indicated elevated levels of As (1.67 to 32.31 ppb) in downstream areas of the river system, influenced by human activities. While metals exhibited correlation with each other, there was a weak association, except for As, with the levels of MPs in the Markanda River. The SEM-EDX analyses to characterize chemical elements absorbed onto the surface of MP showed distinct variations in upstream and downstream sites, with the presence of elements such as Mn, Ni, Cr, Zn, As, Se, and Cu found in downstream areas. We conclude that MPs contaminated with heavy metals potentially threaten the ecological security of freshwater aquatic systems and highlight the importance of management action to reduce plastic pollution worldwide.


Assuntos
Monitoramento Ambiental , Metais Pesados , Microplásticos , Rios , Poluentes Químicos da Água , Metais Pesados/análise , Rios/química , Microplásticos/análise , Poluentes Químicos da Água/análise , Índia , Sedimentos Geológicos/química , Sedimentos Geológicos/análise
13.
Environ Geochem Health ; 46(9): 359, 2024 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-39093343

RESUMO

This study investigates the radon concentration in groundwater in Kupwara, the northernmost district of the Kashmir valley. It further assesses the annual effective dose experienced by the district's diverse population-infants, children, and adults-attributable to both inhalation of airborne radon released from drinking water and direct ingestion. In addition to this, the calculation of gamma dose rate is also carried out at each of the sampling site of radon. A portable radon-thoron monitor and a portable gamma radiation detector were respectively employed to estimate the activity concentration of radon in water samples and to measure the gamma dose rate. The radon concentration was found to exhibit variability from a minimum of 2.9 BqL-1 to a maximum of 197.2 BqL-1, with a mean of 26.3 BqL-1 and a standard deviation of 23.3 BqL-1. From a total of 85 samples, 10.6% of the samples had radon activity concentrations exceeding the permissible limits of 40 BqL-1 set by the United Nations Scientific Committee on Effects of Atomic Radiations as reported by UNSCEAR (Sources and effects of ionizing radiation, 2008) and only 1.2% of the samples have radon activity concentration exceeding the permissible limits of 100 BqL-1 set by the World Health Organization as reported by WHO (WHO guidelines for drinking-water quality, World Health Organization, Geneva, 2008). The mean of the annual effective dose due to inhalation for all age groups as well as the annual ingestion dose for infants and children, surpasses the World Health Organization's limit of 100 µSv y-1 as reported by WHO (WHO guidelines for drinking-water quality, World Health Organization, Geneva, 2008). The observed gamma radiation dose rate in the vicinity of groundwater radon sites ranged from a minimum of 138 nSv h-1 to a maximum of 250 nSv h-1. The data indicated no significant correlation between the dose rate of gamma radiation and the radon levels in the groundwater. Radon concentration of potable water in the study area presents a non-negligible exposure pathway for residents. Therefore, the judicious application of established radon mitigation techniques is pivotal to minimize public health vulnerabilities.


Assuntos
Água Subterrânea , Monitoramento de Radiação , Radônio , Poluentes Radioativos da Água , Radônio/análise , Água Subterrânea/química , Índia , Poluentes Radioativos da Água/análise , Humanos , Água Potável/química , Água Potável/análise , Lactente , Criança , Doses de Radiação , Raios gama , Exposição à Radiação/análise , Adulto
14.
BMC Ecol Evol ; 24(1): 105, 2024 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-39095717

RESUMO

Even though the high plateaus of Qinghai-Tibet and Iran share many faunal elements, the historical biogeography of the species present in this area are not very well understood. We present a complete COI barcode library for Aporia Hübner and a first comprehensive phylogeny for the genus including all known species and majority of subspecies using ten available genes (COI-COII, ND1, ND5, Cytb, EF-1a, Wg, 16S, 28S-D2/D3 and 28S-D8). We then focus on A. leucodice (Eversmann, 1843) and related taxa in order to resolve some long-standing taxonomic issues in this species-group. Based on DNA sequence data as well as morphology, we raise Aporia illumina (Grum-Grshimailo 1890) stat. nov. (= pseudoillumina Tshikolovets 2021 syn. nov.) as a distinct species and designate a lectotype; synonymize Aporia leucodice leucodice Eversmann, 1843 (= A. l. morosevitshae Sheljuzhko, 1908 syn. nov.); and describe a new species, Aporia ahura sp. nov., from the Central Alborz Mountains in northern Iran.


Assuntos
Borboletas , Código de Barras de DNA Taxonômico , Complexo IV da Cadeia de Transporte de Elétrons , Filogenia , Animais , Código de Barras de DNA Taxonômico/métodos , Irã (Geográfico) , Complexo IV da Cadeia de Transporte de Elétrons/genética , Borboletas/genética , Borboletas/classificação , Especiação Genética , Altitude , Feminino , Masculino
15.
Zookeys ; 1208: 81-98, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39100128

RESUMO

Four new species of the genus Camptoscaphiella Caporiacco, 1934 are described from Xizang, China, i.e., C.metok Tong & Li, sp. nov. (♂), C.shannan Tong & Li, sp. nov. (♂♀), C.trifoliata Tong & Li, sp. nov. (♂♀) and C.zayu Tong & Li, sp. nov. (♂♀). Morphological descriptions, photographic illustrations and a distribution map of the four new species are given.

16.
Environ Pollut ; 361: 124629, 2024 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-39074688

RESUMO

The global apprehension regarding the ubiquitous presence of microplastics (MPs) and their associated health risks underscore a significant challenge. However, our understanding on the occurrence and characteristics of this emerging class of pollutants in the different environmental compartments remains limited. For instance, despite housing approximately 20-25% of the global population, the evidence of the atmospheric MPs in Indian Subcontinent is exceedingly rare. Hence, we for the first-time present data on the depositional flux, chemical composition, morphological features of the atmospheric MPs collected from the foothills of Indian Himalayas. The total number of MPs for the collected samples ranged from 65 to 752 particles, with an average of 317 ± 171 particles count. The average flux of atmospheric MPs was 2256 ± 1221 particles/m2/day and varied significantly from 462 particles/m2/day to 5346 particles/m2/day. The highest deposition (5346 particles/m2/day) of atmospheric MPs was recorded during the 3rd week of sampling, coinciding with the Diwali festival. Based on the visual characteristics, we determined that the size of MPs ranged from 67 to 2320 µm, with a predominant presence of smaller particles (<1200 µm), primarily composed of fragments and films/sheets. Raman spectroscopy indicated that the analyzed MPs were mainly composed of 4 different polymer types, including PE (46.8 ± 7.2 %), PP (20.9 ± 7.4 %), PS (15.6 ± 3.8 %) and PET (16.7 ± 9.9 %). We further highlighted the extent to which climate variables control the deposition of atmospheric MPs in this urban conglomerate located in the foothills of Himalayas. Our Lagrangian parcel tracking approach showed that the greater frequencies are of local origin and clustered near to the studied region. We also speculate that atmospheric microplastics can be transported along the westerly winds. Though we did not observe any significant relation (p > 0.05) between meteorological parameters and the quantity of atmospheric MPs.

17.
Sci Rep ; 14(1): 17239, 2024 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-39060353

RESUMO

The Mantle Transition Zone (MTZ) beneath the Uttarakhand Himalaya has been modelled using Common Conversion Point (CCP) stacking and depth-migration of radial P-receiver functions. In the Uttarakhand Himalaya region, the depths of the 410-km discontinuity (d410) and the 660-km discontinuity (d660) are estimated to be approximately 406 ± 8 km and 659 ± 10 km, respectively. Additionally, the thickness of the mantle transition zone (MTZ) is modelled to be 255 ± 7 km. The average arrival times for d410 and d660 conversions are (44.47 ± 1.33) s and (71.08 ± 1.29) s, respectively, indicating an undisturbed slightly deeper d410 and a deformed noticeably deeper d660 in the area. The model identifies the characteristics of the d410 and d660 mantle discontinuities beneath the Lesser Himalayan region, revealing a thickening of the MTZ towards northeast, which could be due to gradual cooling or thickening of the Indian lithosphere towards its northern limit. We simulate a low-velocity layer (perhaps partially molten) above the d410 discontinuity at depths of 350 to 385 km, indicating the presence of a hydrated MTZ beneath the area. We also interpret a negative phase at d660 as a low-velocity layer between 590 and 640 km depths, which could be attributed to the accumulation of old subducted oceanic materials or increased water content at the bottom of the MTZ. Our results suggest the presence of residues from paleo-subducted lithospheric slabs in and below the mantle transition zone underlying the Uttarakhand Himalayas.

18.
Biodivers Data J ; 12: e123669, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39015794

RESUMO

Background: The Asian Cat Snake genus Boiga Fitzinger, 1826 includes 37 species, with high species diversity. Five species of Boiga have been recorded in China including B.multomaculata (Boie, 1827), B.kraepelini (Stejneger, 1902), B.cyanea (Duméril, Bibron & Duméril, 1854), B.guangxiensis (Wen, 1998) and B.siamensis (Nutaphand, 1971). Previously, the validity of the species Boigastoliczkae (Wall, 1909) was controversial. B.stoliczkae was considered in synonymy with B.ochracea. Currently, the taxonomy of B.multomaculata and B.ochracea (Theobald, 1868) was revised so that B.multomaculata and B.ochracea actually represent a single species and B.stoliczkae was recognised as a valid species. B.stoliczkae was previously known to be found in the west from central Nepal through Darjeeling, Sikkim and Bhutan to Arunachal Pradesh and Assam in north-eastern India. New information: One adult female specimen of the Asian Cat Snake was collected from Gyirong County, near the China-Nepal border, Tibet, China during fieldwork on August 2023. We compared morphology and mitochondrial DNA sequence data with all the species of the genus Boiga. Both datasets strongly supported referring the Chinese specimens to B.stoliczkae (Wall, 1909) due to the 21 mid-dorsal scale rows and the uncorrected p-distance (mitochondrial DNA gene cytochrome b) between this specimen and B.stoliczkae which is 1.7%. We further described morphological characters of the Chinese specimen in detail and compared these with the specimens that had been previously described. The dorsal ground colour of the Chinese specimen is dark brown, with a black stripe distributed almost evenly across the tail. This is a novel morph of the species B.stoliczkae. The newly-collected Chinese specimen expands the distribution of the species on the Himalaya range.

19.
Mol Ecol ; 33(15): e17446, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38946613

RESUMO

The Cenozoic topographic development of the Himalaya-Tibet orogen (HTO) substantially affected the paleoenvironment and biodiversity patterns of High Asia. However, concepts on the evolution and paleoenvironmental history of the HTO differ massively in timing, elevational increase and sequence of surface uplift of the different elements of the orogen. Using target enrichment of a large set of transcriptome-derived markers, ancestral range estimation and paleoclimatic niche modelling, we assess a recently proposed concept of a warm temperate paleo-Tibet in Asian spiny frogs of the tribe Paini and reconstruct their historical biogeography. That concept was previously developed in invertebrates. Because of their early evolutionary origin, low dispersal capacity, high degree of local endemism, and strict dependence on temperature and humidity, the cladogenesis of spiny frogs may echo the evolution of the HTO paleoenvironment. We show that diversification of main lineages occurred during the early to Mid-Miocene, while the evolution of alpine taxa started during the late Miocene/early Pliocene. Our distribution and niche modelling results indicate range shifts and niche stability that may explain the modern disjunct distributions of spiny frogs. They probably maintained their (sub)tropical or (warm)temperate preferences and moved out of the ancestral paleo-Tibetan area into the Himalaya as the climate shifted, as opposed to adapting in situ. Based on ancestral range estimation, we assume the existence of low-elevation, climatically suitable corridors across paleo-Tibet during the Miocene along the Kunlun, Qiangtang and/or Gangdese Shan. Our results contribute to a deeper understanding of the mechanisms and processes of faunal evolution in the HTO.


Assuntos
Anuros , Filogenia , Animais , Tibet , Anuros/genética , Anuros/classificação , Biodiversidade , Filogeografia , Evolução Biológica , Transcriptoma , Ecossistema , Clima , Temperatura
20.
Data Brief ; 55: 110602, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38988731

RESUMO

In context with the scientific evidence of aerosol deposition induced snow and glacier melt, this paper provides baseline information about the spatiotemporal variability of aerosols and snow-ice chemistry filling the data and knowledge gap over the western Himalaya, India based on recently published paper [1]. A systematic approach was employed that entailed analysis of aerosol variability over four decades using MERRA-2 (Modern-Era Retrospective analysis for Research and Applications) data over five major mountain ranges in the western Himalaya. Further, data about nine physicochemical parameters was generated over three selected glaciers in the study area. HYSPLIT (HYbrid Single Particle Lagrangian Integrated Trajectory) model simulated air mass sources at weekly intervals. This dataset is valuable for future investigations aimed at understanding and characterizing the impacts of light-absorbing impurities on radiative forcing, albedo changes, snow-melt, glacier recession and water quality in the western Himalaya.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA