Low Altitude Areas Research Articles

Study of the effects of land use change on water yield in the Qilian Mountains in western China

The Qilian Mountains serve as significant ecological security barriers in the western region of China. Their continuous and stable water supply is essential for the sustainability of the human oasis in the Hexi Corridor, as well as for the maintenance of the desert ecosystem in the north. In the past three decades, land use in this area has changed significantly because of human activities, which has had a profound impact on water yield services. Based on the Water Yield module of the InVEST model, we evaluated the area and water yield of land use during 1990–––2020, and discussed the characteristics of water yield response to changes in land use. As a result of the study, it was found that in the Qilian Mountains during the period 1990–––2020: (1) the areas of swamp, unused land, medium coverage grassland, and woodland reduced, while the areas of high coverage grassland, low coverage grassland, cultivated land, construction land, glaciers, and water area increased, and each land use type exhibited a different degree of transformation. (2) In terms of total water yield, this declined by 1.09 × 108 m3, water yield of medium coverage grasslands, unused land, and swamp decreased, while water yield of other land uses increased, however, the responses to the change in water yield as a result of the change in land use were significant. (3) The areas with decreased water yield fall mainly within the high-altitude areas of the Qinghai Lake and Qaidam river watersheds, while the low-altitude areas were characterized by an increase in water yield. This study may provide decision-makers with guidance for protecting the ecosystem of the Qilian Mountains and developing a national park in the Qilian Mountains.

Microcosmic characteristics of particulate matter emitted by GDI gasoline engine in plateau environment

The particulate matter samples of gasoline direction injection (GDI) gasoline engine obtained from road experiments are photographed to obtain the emission particulate matter images based on the transmission electron microscope under high altitude environment. The results show that the micro-morphology characteristics of the particulate matter emitted by GDI gasoline engine in plateau area are similar to those in low altitude area, and the main morphology is cloud-like, filamentous, flocculent, chain-like, cluster-like, like altitude contour line, etc. The images are processed by MATLAB and Python software, and the fractal dimension, average gray value and gray histogram are obtained. The fractal dimensions of the emission particulate data obtained are between 1.81 and 1.89, which has some deviation compared with the fractal dimension of the emission particulate data at low altitude of 1.58 and 1.80. With the increase of altitude, its fractal dimension increases more obviously. It can be seem from the characteristics of gray value and gray histogram of particle images that the average gray value of GDI gasoline engine particles is higher. The gray histogram distribution of 5–50 nm images is uniform, and the individual particles in the images are clear. The gray histogram of 100–500 nm images is scattered, so it is easy to extract and separate the image edge contour. 5–50 nm images are used to study the details and characteristics of individual particles, and 100–500 nm transmission electron microscope images are used to study the overall morphology of particles.

THE SPATIAL PATTERN OF GROTTOES IN CHINA AT THE COUNTY SCALE: A CASE STUDY OF ANYUE COUNTY

Abstract. Grottoes in China are crucial components of immovable cultural heritage. According to the 2020 national survey conducted by the State Administration of Cultural Heritage, the Sichuan-Chongqing region boasts a total of 2,850 grottoes and rock carvings, accounting for approximately half of the national total. Among these, Anyue County, situated in the central part of Sichuan Province, stands out as one of the most concentrated and distinctive areas for grottoes in the Sichuan-Chongqing region. Therefore, conducting a spatial pattern analysis of grottoes holds significant theoretical and practical value for the protection and cultural dissemination of cultural heritage in Anyue County. Building upon the spatial distribution of grottoes in Anyue County, this study integrates multiple geospatial data sources, such as water systems and elevation. By employing methods such as buffer analysis, kernel density analysis, and standard deviation ellipse analysis, it delineates the spatial distribution pattern in Anyue County and preliminarily identifies their Spatial distribution rules. The findings of this study are as follows: (1) Within the administrative boundaries of Anyue County, grottoes exhibit a distribution pattern characterized by "less in the west and more in the east" and "one belt with three cores." (2) Grottoes and rock carvings in Anyue County primarily concentrate within a 1500-meter range on both sides of rivers, with the number decreasing as the distance from the rivers increases. Moreover, there are significantly fewer sites near inward-flowing rivers compared to outward-flowing rivers. (3) Natural factors influence the distribution of grottoes, with the number of grottoes being much lower in higher-altitude areas than in lower-altitude areas.

Emission Characteristics of Heavy-Duty Vehicle Diesel Engines at High Altitudes

The aim of this study was to accurately quantify the emission characteristics of pollutants at different altitudes. We used an intake and exhaust altitude simulation system that could simulate the intake and exhaust pressures of a national sixth vehicle diesel engine at different altitudes. Experimental research was conducted on the World Harmonized Transient Cycle (WHTC) and World Harmonized Steady State Cycle (WHSC) of the diesel engine. The results showed that carbon monoxide (CO) emissions increased with the altitude at full load, but their rates were significantly reduced at low speed (800 rpm), increasing by 0.0084–0.665 ppm/m. Hydrocarbon (HC) emissions showed an initial decreasing and then increasing trend, with a rise of up to 30%. Nitrogen oxides (NOx) showed a linear decreasing trend, especially at low speed. With the increase in altitude, the cycle work of the diesel engine decreased in a non-linear manner, and the decrease became more pronounced above 3000 m. The raw emission results of the WHTC and WHSC tests also revealed that CO increased exponentially, NOx decreased slightly and then increased rapidly, HC increased linearly, and the emissions of all pollutants deteriorated significantly above 3000 m. The exhaust emission results of the WHTC and WHSC tests showed that the CO emission showed an initial decreasing and then increasing trend with the elevation of the altitude, approximately 15 ± 5 mg/kWh. HC emissions showed an increasing trend, with HC emissions of 3 – 6 mg/kWh for the WHTC and 1 – 2 mg/kWh for the WHSC. NOx emissions did not follow any obvious rule, while the particulate matter (PM) tended to increase and then decrease with the elevation of the altitude. In relation to the current emission standards, the limit value margin for CO and HC exhaust emissions is greater than 95% and the limit value margin for PM emissions is greater than 88% at an altitude of 4000 m. The NOx emission limit is greater than 87% (within 3000 m), but there is a risk of exceeding the limit above 3000 m. The second sampling data from the WHTC and WHSC showed that the raw emissions of the engine were higher in the high-altitude area than in the low-altitude area, but the change law of the exhaust emissions was not obvious, and the levels of both emissions were low.

Evaluating the Effect of Vegetation Index Based on Multiple Tree-Ring Parameters in the Central Tianshan Mountains

Combining tree ring data with remote sensing data can help to gain a deeper understanding of the driving factors that influence vegetation change, identify climate events that lead to vegetation change, and improve the parameters of global vegetation index reconstruction models. However, it is currently not well understood how climate change at different elevations in the central Tianshan Mountains affects radial tree growth and the dynamics of forest canopy growth. We selected Schrenk spruce (Picea schrenkiana) tree core samples from different elevations in the central Tianshan Mountains. We analyzed the relationships of various tree-ring parameters, including tree-ring width, maximum latewood density (MXD), and minimum earlywood density (MID) chronologies, with 1982–2012 GIMMS (Global Inventory Modelling and Mapping Studies) NDVI (Normalized Difference Vegetation Index), 2001–2012 MODIS (moderate resolution imaging spectroradiometer) NDVI, and meteorological data. (1) There were strong correlations between tree-ring width chronologies and the lowest temperatures, especially in July. Tree-ring width chronologies at higher altitudes were positively correlated with temperature; the opposite pattern was observed at lower altitudes. MID chronologies were positively correlated with July temperature in high-altitude areas and mean temperature and highest temperature from May to September in low-altitude areas, and negatively correlated with precipitation during this period. MXD chronologies were mainly negatively correlated with precipitation. MXD chronologies were mainly positively correlated with temperature in April and May. (2) The correlations between MXD chronologies at each sampling point and NDVI in each month of the growing season were strong. Both MID and MXD chronologies were negatively correlated with GIMMS NDVI in July. The overall correlations between tree-ring parameters and MODIS NDVI were stronger than the correlations between tree-ring parameters and GIMMS NDVI in high-altitude areas; the opposite pattern was observed in low-altitude areas. Drought stress may be the main factor affecting tree ring parameters and NDVI. In the future, we should combine tree ring parameters with vegetation index to investigate a larger scale of forests.

A comparison of quality of life between older adults living in high and low altitude areas.

High altitude is known to have a significant impact on human physiology and health, therefore, understanding its relationship with quality of life is an important research area. This study compared the quality of life (QOL) in older adults living in high and low altitude areas, and examined the independent correlates of QOL in those living in a high altitude area. Older adults living in three public nursing homes in Xining (high altitude area) and one public nursing home in Guangzhou (low altitude area) were recruited. The WHOQOL-BREF was used to measure the QOL. 644 older adults (male: 39.1%) were included, with 207 living in high altitude and 437 living in low altitude areas. After controlling for the covariates, older adults living in the high altitude area had higher QOL in terms of physical (P = 0.035) and social domains (P = 0.002), but had lower QOL in psychological (P = 0.009) domain compared to their counterparts living in the low altitude area. For older adults living in the high altitude area, smoking status was associated with higher social QOL (P = 0.021), good financial status was associated with higher physical QOL (P = 0.035), and fair or good health status was associated with higher physical (p < 0.001) and psychological QOL (P = 0.046), while more severe depressive symptoms were associated with lower QOL. Appropriate interventions and support to improve depressive symptoms and both financial and health status should be developed for older adults living in high altitude areas to improve their QOL.

Comparisons of Rainfall Microphysical Characteristics between the Southeastern Tibetan Plateau and Low-Altitude Areas

Abstract The low air pressure and density over the Tibetan Plateau may have an impact on the microphysical features of rainfall. Using a two-dimensional video disdrometer (2DVD), a Micro Rain Radar (MRR), and a microwave radiometer (MWR), the features of the raindrop size distribution (DSD) on the southeastern Tibetan Plateau (SETP) are explored and compared with those in low-altitude regions. The falling speed of raindrops on the SETP is higher than that in low-altitude areas. Under different rainfall-rate categories, the number concentration and the maximum diameter of raindrops on the SETP are smaller than those in low-altitude regions. The convective rainfall on the SETP is more maritime-like because the South Asian summer monsoon brings water vapor from the ocean here. For stratiform and convective rainfall, the SETP has more small-sized raindrops than low-altitude locations. The mass-weighted mean diameters (Dm) on the SETP are the smallest among six sites. The generalized intercept parameter (Nw) of stratiform rainfall is balanced at a low rainfall rate, while that of convective rainfall is balanced at a high rainfall rate. Furthermore, for a given μ (the shape parameter of gamma distribution) value, the λ (the slope parameter of gamma distribution) value on the SETP is the highest of the six sites. Significance Statement For the occurrence and progression of rainfall, microphysical processes (for instance, collision, fragmentation, coalescence, and evaporation) that take place when rainfall particles descend are crucial. A key factor in the microphysical features of rainfall that varies with rainfall rates and types is the raindrop size distribution (DSD). The southeastern Tibetan Plateau (SETP)’s unique terrain ensures that there is enough moisture for rain to fall there, but little is known about the microphysical aspects of this type of precipitation. There has not been enough research done on how the high altitude affects the microphysical features of rainfall. The microphysical features of rainfall in this area must thus be studied.

Postural behavior of rhesus monkeys at high altitude (Shimla and low altitude area in Himachal Pradesh

Postural behavior of rhesus monkeys at high altitude (Shimla and low altitude area in Himachal Pradesh

Characteristics of photosynthetic rates in different vegetation types at high-altitude in mountainous regions

Mountains play an important role in the carbon cycle of the terrestrial ecosystem and are one of the most sensitive ecosystems to climate change. However, our current knowledge regarding the physiological responses of alpine plants to environmental changes remains limited due to the severe climatic conditions prevailing in these high-altitude regions. Therefore, this study quantified the variations in photosynthetic rates (An) and identified their driving factors of herbaceous plants, shrubs, and trees along an elevation gradient (2200 m asl to 3200 m asl) on Mount Gongga. Elevation emerged as a significant determinant of An, with a general increase observed, albeit followed by a decline above 3000 m asl. In high-altitude regions, trees displayed more significant fluctuations in An compared to herbaceous plants and shrubs. The lower levels of atmospheric carbon dioxide concentration (eCO2) and temperature in high-altitude regions resulted in a 16 % increase in An for herbaceous plants, 60 % increase for shrubs, and 43 % increase for trees compared to the low-altitude areas. Structural equation modeling (SEM) analyses underscored the considerable impact of environmental factors on An. Notably, photosynthetically active radiation, eCO2, and stomatal conductance were identified as positive influencers, while other factors exerted negative effects. Our results further highlighted that trees were subject to greater constraints from multiple factors compared to herbs and shrubs, aligning with the outcomes of our variance analysis. In summary, our study presents a comprehensive assessment of vegetation responses to environmental factors along elevational gradients. The significance of An in plants at high altitude to external factors suggests the potential adaptability of alpine plants, and also indicates that changes in photosynthetic physiological functions at high altitude should be paid more attention to in the study of climate change.

Dynamic changes in the suitable areas for the pinewood nematode in the Sichuan-Chongqing Region of China.

The pine wood nematode (PWN), one of the largest alien forestry pests in China, has caused numerous deaths of conifer forests in Europe and Asia, and is spreading to other suitable areas worldwide. Information on the spatial distribution of the PWN can provide important information for the management of this species. Here, the current and future geographical distributions of PWN were simulated in the Sichuan-Chongqing region of China in detail based on the MaxEnt model. The results indicated excellent prediction performance, with an area under curve score of more than 0.9. The key factors selected were the altitude, maximum temperature of the warmest month, annual precipitation, precipitation of the wettest quarter, and minimum temperature of the coldest month, with thresholds of < 400 m, > 37.5 °C, 1100-1250 mm, 460-530 mm and > 4.0 °C, respectively, indicating that the PWN can live in low-altitude, warm, and humid areas. The suitable region for the PWN is mainly concentrated in the metropolitan area, northeast of Chongqing, and the southeastern and eastern parts of Sichuan Province. Most importantly, in addition to their actual distribution area, the newly identified suitably distribution areas A, B, C, and D for the coming years and E, F, G, and H for the period-2041-2060 (2050s) should be strictly monitored for the presence of PWNs. Altogether, the suitable distribution ranges of the PWN in the Sichuan-Chongqing region show an increasing trend; therefore, owing to its inability to disperse by itself, human activities involving pine trees and vectors of the Japanese pine sawyer should be intensively controlled to prevent the PWN from spreading to these newly discovered suitable areas.

Adaptive response of Siberian roe deer Capreolus pygargus to climate and altitude in the temperate forests of South Korea

Understanding climatic effect on wildlife is essential to prediction and management of climate change's impact on the ecosystem. The climatic effect can interact with other environmental factors. This study was aimed to determine effects of climate and altitude on Siberian roe deer Capreolus pygargus activity in temperate forests of South Korea. We conducted camera trapping to investigate roe deer's activity level from spring to fall. Logistic regressions were used to determine effects of diel period, temperature, rain, and altitude on the activity level. A negative relationship was noted between temperature and the activity level due to thermoregulatory costs. Roe deer activity exhibited nocturnal and crepuscular patterns during summer and the other seasons, respectively, possibly due to heat stress in summer. In addition, the effect of temperature differed between high‐ and low‐altitude areas. In low‐altitude areas, temperature affected negatively the activity level throughout the study period. Conversely, in high‐altitude areas, temperature affected activity level only in summer and early fall. Lower temperatures in higher altitudes favoured roe deer activity, resulting in roe deer's preference towards higher altitude areas. However, roe deer's movement toward lower altitudes was observed in summer. Reduced heat stress by changing activity pattern allowed them to access lower altitude areas with greater resource availability during summer. This study revealed how roe deer activity varied across seasons and altitudes, considering the interactions among weather, microclimate and resource availability. It provides insight into how montane species adapt to various climatic conditions, and this could have important implications for wildlife management and conservation efforts.

Can Farmers Punch Their Tickets to Wealth? The Spillover Effect of High-Speed Railway on Agriculture Development

This paper studied the impact of high-speed railway linesonagricultural outputin the regions along their routes. It also investigated the heterogeneity of this impactbased on the terrain characteristics. The results of empirical testsusing county-level data show that ahigh-speed railway line can bring higher agricultural “dividends” to counties along the line. Notably, low altitude areas and regionswith gentle terrain exhibit a more pronounced promotional effect on local agricultural output. High-speed railways mainly promote agricultural output by promoting the mechanization of agriculture in counties along the route, thus reinvigorating the agricultural population and the development of specialty agriculture. Ourfindingsprovide quasi-microscopic evidence of the potential benefits of transportation infrastructure construction to break down geographical barriers and facilitate production factor flow, and providesa theoretical basis for the economic spillover effects of high-speed railway construction.

Improved stacked ensemble with genetic algorithm for automatic ECG diagnosis of children living in high-altitude areas

Electrocardiogram (ECG) is a commonly used diagnostic tool in clinical practice that plays a vital role in the diagnosis and treatment of various heart diseases. Previous studies have indicated that the incidence of heart disease in children living in high-altitude areas is significantly higher than those in low-altitude areas, which increases the demand for ECG examinations in these regions. However, there is a lack of research and technology that focus on automatic ECG diagnosis for children in high-altitude areas. This study utilized electronic medical records of pediatric electrocardiograms (ECGs) from high-altitude areas in Yunnan Province, China as research data. An improved genetic algorithm (GA) was employed to find the best combination of base classifiers, and a stacked ensemble approach was utilized to develop a reliable model for automatic diagnosis of pediatric ECGs. The developed model is capable of identifying abnormal ECGs and classifying heart rhythm types into four categories: normal sinus rhythm, sinus tachycardia, sinus bradycardia, and other arrhythmias. The model was tested and compared with commonly used classification methods. The results show that the model developed in this paper exhibits better performance in terms of accuracy, recall, and F1 score. The model’s classification effectiveness was further demonstrated by creating a receiver operating characteristic (ROC) curve. Finally, feature importance analysis highlighted the significance heart rate, developmental stage, and QRS complex axis deviation angle in the model.

Permafrost Probability Mapping at a 30 m Resolution in Arxan Based on Multiple Characteristic Variables and Maximum Entropy Classifier

High-resolution permafrost mapping is an important direction in permafrost research. Arxan is a typical area with permafrost degradation and is situated on the southern boundary of the permafrost region in Northeast China. With the help of Google Earth Engine (GEE), the maximum entropy classifier (MaxEnt) is used for permafrost mapping using the land surface temperature (LST) of different seasons, deviation from mean elevation (DEV), solar radiation (SR), normalized difference vegetation index (NDVI), and normalized difference water index (NDWI) as the characteristic variables. The prior data of permafrost distribution were primarily based on 201 borehole data and field investigation data. A permafrost probability (PP) distribution map with a resolution of 30 m was obtained. The receiver operating characteristic (ROC) curve was used to test the distribution results, with an area under the curve (AUC) value of 0.986. The results characterize the distribution of permafrost at a high resolution. Permafrost is mainly distributed in the Greater Khingan Mountains (GKM) in the research area, which run from the northeast to the southwest, followed by low-altitude area in the northwest. According to topographic distribution, permafrost is primarily found on slope surfaces, with minor amounts present in peaks, ridges, and valleys. The employed PP distribution mapping method offers a suggestion for high-resolution permafrost mapping in permafrost degradation areas.

The Archijassidae from the Jurassic of China (Hemiptera, Cicadomorpha, Membracoidea) and its palaeoecological significance

ABSTRACT The extinct hemipteran family Archijassidae is recorded in the late Middle Triassic to mid-Cretaceous, which is regarded as the ‘ancestral’ group of Membracoidea. The archijassid species Kisa fasciata was previously known confined to the Middle Jurassic Itat Formation of Krasnoyarsk, Russia. Here, we report seventeen new specimens of K. fasciata from the Middle-Upper Jurassic Yangshuzhuang Formation in Jiyuan City, Henan Province, and the Middle Jurassic Yan’an Formation in Yan’an City, Shaanxi Province, which are located in Jiyuan Basin and Ordos Basin of northern China, respectively. The considerable intraspecific variation of K. fasciata is revealed. The new discovery extends the palaeobiogeographic distribution of Archijassidae in Eurasia, and indicates that K. fasciata would appear to widely distribute in the temperate low-altitude areas of eastern and northern Eurasia in the Middle Jurassic, which provides new insight into the palaeoecology of north central China and central Siberia during this time.

Spatial heterogeneity analysis of matching degree between endangered plant diversity and ecosystem services in Xishuangbanna.

Biodiversity and ecosystem services (ESs) are closely linked. Human activities have caused critical damage to the habitat and ecosystem function of organisms, leading to decline in global biodiversity and ecosystem services. To ensure sustainable development of local ecological environments, it is critical to analyze the spatial matching degree of biodiversity and ESs and identify ecologically vulnerable areas. Taking Xishuangbanna, southern China, as an example, we constructed a pixel-scale matching degree index to analyze the spatial matching degree of endangered plant diversity (EPD) and four ESs and classified the matching degree into low-low, low-high, high-low, and high-high four types. The results revealed a mismatch relationship of EPD and ESs in more than 70% of areas. Under the influence of altitude and land use/land cover (LULC) type, the matching degree of EPD and ESs showed obvious spatial heterogeneity. In low-altitude areas in the south of Xishuangbanna, EPD and ESs mainly showed mismatch, while high-altitude areas in the west had a better match. Natural forest was the main land cover in which EPD and ESs showed high-high match and its areal proportion was much larger than that of rubber plantation, tea plantation, and cropland. Our findings also stress the need to concentrate conservation efforts on areas exhibiting a low-low match relationship, indicative of potential ecological vulnerability. The pixel-scale spatial matching degree analysis framework developed in this study for EPD and ESs provides high-resolution maps with 30 m × 30 m pixel size, which can support the implementation of ecological protection measures and policy formulation, and has a wide range of applicability. This study provides valuable insights for the sustainable management of biodiversity and ESs, contributing to the strengthening of local ecological environment protection.

Serum metabolomics of hyperbilirubinemia and hyperuricemia in the Tibetan plateau has unique characteristics

Few studies have provided data on the metabolomics characteristics of metabolic diseases such as hyperuricemia and hyperbilirubinemia in the Tibetan plateau. In the current study, we sought to investigate the serum metabolomics characteristics of hyperbilirubinemia and hyperuricemia in the Tibetan plateau, with the aim to provide a basis for further research on their pathogenesis, prevention, and treatment. The study participants were born in low-altitude areas below 1000 m and had no prior experience living in a high-altitude area before entering Golmud, Tibet (average elevation: 3000 m) and Yushu, Qinghai (average elevation: 4200 m). Thirty-four participants with hyperbilirubinemia (18 in Golmud and 16 in Yushu), 24 participants with hyperuricemia, and 22 healthy controls were enrolled. The serum samples of subjects were separated and then sent to a local tertiary hospital for biochemical examination. Serum widely targeted technology, based on the ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) platform, was used to detect serum metabolites and differential metabolites. Compared to the healthy controls, hyperbilirubinemia patients from Golmud showed 19 differential metabolites, hyperbilirubinemia patients from Yushu showed 12 differential metabolites, and hyperuricemia patients from Yushu showed 23 differential metabolites. Compared to the hyperbilirubinemia patients from Golmud that is at a low altitude, the Yushu groups had 33 different metabolites. Differential metabolites are primarily classified into amino acids and their derivatives, nucleotides and their derivatives, organic acids and their derivatives, and lipids/fatty acids. These are related to metabolic pathways such as caffeine metabolism, arachidonic acid metabolism, and tyrosine metabolism. Hyperbilirubinemia and hyperuricemia in the Tibetan plateau have unique serum metabolomics characteristics. Glycine derivatives and arachidonic acid and its derivatives were associated with plateau hyperbilirubinemia, and vanillic acid and pentadecafluorooctanoic acid were associated with plateau hyperuricemia.

Warming and Wetting will continue over the Tibetan Plateau in the Shared Socioeconomic Pathways.

We have used bias-corrected data from CMIP6 models to drive a regional climate model and project climate on the Tibetan Plateau (TP) in the 21st century. Changes in two background fields, namely, 2-meter air temperature and total precipitation, were analyzed. The results show that the WRF simulations capture the terrain effect that cannot be represented in low-resolution models. The simulation of temperature is better in summer than in winter, while the simulated precipitation is the opposite. By the end of the 21st century, the entire TP region experiences significant warming, with an average warming of 3°C and 7°C in the SSP245 and SSP585 scenarios, respectively. The western region shows a greater warming amplitude, with a maximum of more than 10°C in the SSP585 scenario. Most regions of the TP had significant increases in precipitation by the end of the 21st century, with precipitation increasing by 90 mm and 200 mm in the two scenarios, respectively. However, in the low-altitude areas of southeastern TP, total winter precipitation is significantly reduced in the SSP585 scenario. The strengthening of the East Asian summer monsoon and westerly disturbances collectively leads to a significant increase in precipitation within the TP region. By the end of the 21st century, the average annual precipitation in the TP is projected to reach approximately 600 millimeters.

Assessment of suitable cultivation region for Pepino (Solanum muricatum) under different climatic conditions using the MaxEnt model and adaptability in the Qinghai–Tibet plateau

Pepino (Solanum muricatum), a member of the Solanaceae family originating from South America, is cultivated globally. However, the cultivation range and suitable habitat of Pepino have not been extensively studied, which hampers the further development of its cultivation industry. Therefore, we aimed at enrich and expand the planting scope of Pepino. Currently, the main cultivation areas of Pepino in China are the Yunnan–Guizhou Plateau and the Loess Plateau, where the altitude is above 1000 m. In this study, ArcGIS combined with the MaxEnt model was used for prediction, whose area under curve value was 0.949. The main climatic factors affecting the distribution of Pepino are temperature seasonality, annual means temperature, mean temperature of the coldest quarter, elevation, isothermality, and the climate factors, and their cumulative contribution rate of 87.6%. Pepino's main potential distribution areas are located in Yunnan–Guizhou Plateau, Yunnan Province, Hexi Corridor of Loess Plateau, and low altitude areas of Qinghai–Tibet Plateau. The main distribution ranges from 1000 to 2000 m above sea level, and the total suitable area accounts for 20.09% of China's total land area. The prediction results reveal an expanded potential area for Pepino, with no significant migration in the central region of the main potential distribution area by 2050 and 2070. No studies have been conducted on the open-area cultivation of Pepino in northern China. Our findings revealed that the yield and quality in the four experimental sites and final actual cultivation conditions were consistent with the predicted results of MaxEnt. The yiel d per plant in Xunhua and Minhe was significantly different from that in Xining, which was low, and that in Minhe was the highest. Overall, the fruit quality in the Xining region was the lowest among the three regions, which was related to the climatic differences in each region. These results align with the predicted outcomes, indicating that Xining is the least suitable area. Further, these data verify the accuracy of the prediction results. The climate data of the four regions were analyzed simultaneously to elucidate the influence of different climate conditions on the growth of Pepino. Our findings are of considerable significance for introducing characteristic horticultural crops in the Qinghai–Tibet Plateau and using the MaxEnt model to predict the cultivation range of crops.

TNF-α and IL-8 levels are positively correlated with hypobaric hypoxic pulmonary hypertension and pulmonary vascular remodeling in rats.

The expression status of proinflammatory cytokines in high-altitude pulmonary arterial hypertension (PAH) has been well studied. However, the changes in interleukin (IL)-8 and tumor necrosis factor α (TNF-α) during the reversible changes in pulmonary vascular remodeling (PVR) in PAH after detaching from a hypobaric hypoxic environment have not been elucidated. This investigation elucidated a high-altitude PAH rat model. Then, PAH rats in the high-altitude group were maintained in the high-altitude area, and rats in the low-altitude group returned to the low-altitude area. After 0, 10, 20, and 30 days of PAH modeling, right ventricular systolic pressure (RVSP) and the mean pulmonary arterial pressure (mPAP) were assessed. Right ventricular (RV) hypertrophy was reflected by the ratio of RV/[left ventricle + interventricular septum (S)]. Pathological changes in PVR were accessed by hematoxylin-eosin staining, and medial wall thickness (WT%) and medial wall area (WA%) were measured. TNF-α and IL-8 levels in pulmonary artery tissues and blood were measured with Western blot assay and enzyme-linked immunosorbent assay, respectively. Our results showed that PAH rats exhibited a substantial increase in RVSP and mPAP, RV hypertrophy, PVR, and enhanced generation of TNF-α and IL-8. Then, we found that these pathological changes were gradually aggravated and TNF-α and IL-8 levels were increased in rats in the high-altitude group after 10, 20, and 30 days of PAH modeling. In contrast, the mPAP was decreased and PVR was alleviated in rats in the low-altitude group, accompanying with reduced TNF-α and IL-8 production. In conclusion, our study demonstrated that the generation of TNF-α and IL-8 was also reversible during the reversible changes in PVR after detaching from a hypobaric hypoxic environment. Thus, proinflammatory cytokine TNF-α and IL-8 levels are positively correlated with PVR severity.