Southwest China Research Articles

Unirrigated Extensive Green Roofs in Humid Subtropics – Plant Selection and Substrate Design for Low Maintenance and Climate Resilience

Low-maintenance extensive green roofs hold the potential for adapting to climate change, but there is a limited understanding of their effective design in humid subtropical regions. In this study, we aimed to investigate low-maintenance green roof ecosystems capable of thriving under heat stress. Plant growth performance was evaluated in the second year of an experimental green roof in southwest China. This green roof was unirrigated and involved two plant communities (forbs and grasses) cultivated in four substrate types. Metrics of growth performance, including plant survival, green coverage, visual appearance, leaf stomatal conductance, and substrate volumetric water content were used to analyze the impact of substrate on plant growth. ESP substrate, comprising 30%v (percent of volume) expanded shale, 25%v perlite, 25%v vermiculite, and 20%v compost, featured the highest porosity and optimal growth of forbs, achieving an average green coverage of 66.76% and average visual appearance value of 3.56 throughout the monitoring period. The high total porosity of this substrate could be critical in facilitating root development and drainage. Moreover, during the summer’s heat and drought, while substrate water content is not a limiting factor for the survival of some established forbs, it remains crucial for the growth of grasses. Additionally, the same substrate impacts different plant communities variably. Four particularly well-performing forb species, namely Lycoris chinensis, Tradescantia pallida, Liriope muscari, and Salvia farinacea, demonstrated survival rates closed to 100% and an average visual appearance value exceeding 3 was noted, and thus, they are recommended as plant candidates for unirrigated green roofs. The distinguished performance of these species is attributable to their adaptation to heat and drought through specific physiological traits. Our findings provide insights into vegetation selection and substrate optimization for the successful establishment of extensive green roofs that can be feasibly developed without irrigation in the humid subtropical regions.

Association of socioeconomic and lifestyle factors with prevalence of diabetes in rural southwest China: a structural equation modelling approach

ObjectivesThis study aimed to investigate the prevalence of diabetes using structural equation modelling (SEM) to examine the pathways and associations of socioeconomic and lifestyle factors on diabetes in rural southwest...

Characteristics of forest understory herbaceous vegetation and its influencing factors in biodiversity hotspots in China

Forest ecosystems, especially within biodiversity hotspots, heavily rely on the often-overlooked understory herbaceous communities (USHC) for their structural integrity and ecological functions. Because of their modest stature, these communities have garnered insufficient attention from researchers. Therefore, in this study attention is focused on USHC, which attempts to fill this research gap. To achieve this, we established 105 sample plots in 2022 within forest ecosystems situated in the biodiversity hotspot of southwest China. Our investigation unveiled a rich biodiversity tapestry, identifying 424 plant species from 108 families and 284 genera. Notable were the 217 herbaceous species identified in the understory layer, representing 67 families and 163 genera. These understory herbaceous species accounted for 51.2 % of the overall species count. Through a detailed analysis, the sample plots were categorized into eight distinct communities using a two-way indicator species analysis. These communities exhibited diverse variations in species composition, diversity, biomass, and nutrient characteristics. Notably, community I (Eucalyptus robusta Smith + Rubus corchorifolius L. f. + Alternanthera philoxeroides (Mart.) Griseb.), V (Camptotheca acuminata Decne + Rubus parkeri Hance + Iris tectorum Maxim), VIII (Platycladus orientalis (L.) Franco + Viburnum dilatatum Thunb. + Cyclosorus interruptus (Willd.) H. Ito) stood out for their exceptional species diversity and productivity. Moreover, correlation analyses highlighted the substantial impact of topographic and soil factors on USHC. Altitude, soil water content, and total carbon content emerged as the primary determinants of species diversity. Biomass demonstrated close associations with total soil carbon and nitrogen. Furthermore, the nutrient characteristics displayed significant correlations with soil nutrient contents. These findings underscore the critical importance of prioritizing USHC attention in forest conservation and management strategies within biodiversity hotspots. The implications strongly advocate for the inclusion of these communities in planning and decision-making processes, emphasizing their pivotal role in maintaining structural and functional diversity in ecosystems.

Revealing various change characteristics and drivers of ecological vulnerability in the mountains of southwest China

Ecological vulnerability (EV) assessment is an important means of reflecting the evolutionary process of the local ecological environment, which is crucial for ecological security. The current EV assessment still faces challenges in comprehensively revealing its spatio-temporal change characteristics due to diversity, multi-scale complexity and non-linearity of ecosystems. In this study, we comprehensively revealed the spatio-temporal change features and driver mechanisms of EV in Yunnan Province (YP) using methods such as breaks for additive seasonal and trend (BFAST) and Geodetector. According to the findings, (1) the ecological vulnerability index (EVI) in YP decreased by 0.0265 on the raster scale between 2000 and 2018, and the ecological vulnerability level (EVL) was mainly dominated by level III. At the city scale, EVL in YP was dominated by level IV. At the basin scale, the average EV of the Jinsha River basin was much greater other basins. (2) The linear trend of EV in the YP mainly showed an insignificant decrease, mostly concentrated in the YP’s eastern region. The non-linear trend mainly showed a monotonous decrease, with the mutation time concentrated in 2009. The future persistence trend of EV under different coupling modes was dominated by anti-persistence decrease (Sen-MK + Hurst) and anti-persistence monotonous decrease (BFAST + Hurst), with an area percentage of 40.19 % and 25.13 %, respectively. (3) Gross primary productivity was the priority factor influencing YP’s EV (q = 0.4137). This study not only enriches the cases of EV assessment studies in the high mountain valley area but also bridges the gap of analysing the multi-spatial scale characteristics and change trends of regional EV.

Reciprocal regulation between rural settlement expansion and human-elephant conflict in China's wild elephant range

Human-wildlife conflict (HWC) and its socioeconomic impacts are a pressing global issue. Accurately quantifying HWCs and their interaction with residential development is crucial for rural revitalization and biodiversity conservation efforts. This study investigates the interplay between rural residential expansion (RRE) with human-elephant conflict (HEC) in southern Yunnan Province using high-accuracy yearly land use/land cover data and Asian elephant accident data. A piecewise regression along with several metrics, including expansion intensity and rate of rural residential land, and residential density, were employed to analyze the spatial-temporal change characteristics of RRE. Then, a geographical detector and a bivariate spatial autocorrelation model were used to reveal the driving mechanisms of RRE, with particular emphasis on the spatial relations between RRE and HECs. The results indicate that HECs had a significant negative impact on RRE, exhibiting higher expansion intensity and rate of rural residential land in non-HEC areas than in HEC areas. High spatiotemporal consistency between accelerated RRE and intensified HECs occurred from 2010 onwards, which aligns with the year when the trend of settlement area expansion changed. RRE activities and ensuing land use conversions led to increased occurrences of HECs, which negatively affected the RRE. Compared to HECs, topography and locational factors exhibited a secondary effect on RRE activities. The findings underscore reciprocal feedback mechanisms between RRE and HECs and the elevated risk of adverse interactions between humans and elephants within the range of China's wild elephants, providing theoretical support for coordinating conservation initiatives for Asian elephants with rural revitalization in the border areas of Southwest China.

Climatic suitability and development potential of facility agriculture at county-level in China

Facility agriculture is a modern cultivation system that utilizes certain facilities and engineering techniques to create a suitable environment for crops growth, which can ensure China's national food security and human nutrition. Both beneficial and limited climatic conditions have influenced the development for facility agriculture. In this study, 12 dominant factors were distilled by using Maximum Entropy model (MaxEnt) to quantify climatic suitability of facility agriculture and its variation in counties across China in 1991–2020. The climatic suitable areas for facility agriculture were mainly distributed in the southern part of Northeast China, North China, central China, southern part of Southwest China, and northern part of East China, especially during 2000–2020. There was a general fluctuating upward trend in the climatic suitability of facility agriculture in traditional advantageous production areas such as Jiangsu, Shandong, Hebei, and Liaoning. Positive trends in the changes of climatic suitability were detected in central and eastern China where rapid development of facility agriculture could be realized through scientific planning and layout. Western provinces such as Gansu, Shaanxi, and Inner Mongolia were highlighted as considerable development potential for facility agriculture, with the perspective of developing energy-saving solar greenhouses in especial. These distribution characteristics and potential changes of climate suitability would help to optimize production layout and achieve green and sustainable development of facility agriculture.

Changes in the Antimicrobial Resistance and Bacterial Epidemiology of Moraxella catarrhalis from Pediatric Community-Acquired Pneumonia Patients During the COVID-19 Pandemic: A 5-Year Study at a Tertiary Hospital of Southwest China.

This study aimed to assess the impact of the COVID-19 pandemic on Moraxella catarrhalis infections in pediatric patients hospitalized with community-acquired pneumonia (CAP). The epidemiological features and antimicrobial resistance (AMR) patterns of M. catarrhalis were compared between the pre-pandemic period (2018-2019) and during the pandemic (2020-2022). The results revealed a marked increase in the positivity rate of M. catarrhalis in 2020 and 2021 compared with the pre-pandemic years. The median age of the patients increased significantly in 2021 and 2022, while the proportion of male patients decreased substantially from 2019 to 2021. In addition, there were notable changes in the co-infections of Haemophilus influenzae, parainfluenza virus, and respiratory syncytial virus during the COVID-19 pandemic. The AMR profile of M. catarrhalis also changed significantly, showing increased resistance to ampicillin, but decreased resistance to trimethoprim-sulfamethoxazole and ofloxacin, and a lower proportion of multidrug-resistant isolates. Notably, ampicillin resistance increased among β-lactamase-producing isolates. Before the pandemic, the number and detection rate of isolates, along with resistance to ampicillin and trimethoprim-sulfamethoxazole, were seasonally distributed, peaking in autumn and winter. However, coinciding with local COVID-19 outbreaks, these indices sharply fell in February 2020, and the number of isolates did not recover during the autumn and winter of 2022. These findings indicate that the COVID-19 pandemic has significantly altered the infection landscape of M. catarrhalis in pediatric CAP patients, as evidenced by shifts in the detection rate, demographic characteristics, respiratory co-infections, AMR profiles, and seasonal patterns.

Climate factors and food availability shape the altitudinal migration of birds in the Xiling Snow Mountains, China.

Many bird species in montane regions display altitudinal migration, but so far, the underlying ecological driving mechanisms are not clear. We studied the altitudinal migration behavior patterns and factors influencing altitudinal migration in the Xiling Snow Mountains, which are part of the Hengduan mountain range in southwest China. We recorded the local bird diversity, the seasonal change of: the average temperature (AT), the average humidity (AH), the average invertebrate biomass (AIB), and the amount of plant food sources (PFS) at two study sites (∼1300 and ∼2100 m a.s.l.) during two migration seasons from September 2022 to May 2023. During our surveys, we recorded 96 bird species in total. Among these, 15 altitudinal migrants were identified. The most common family among altitudinal migrants was Leiothrichidae. AT, AIB, and PFS had a significant positive correlation with the monthly number of individuals (MNI) several bird species, implying that increasing temperatures and an increasing abundance of invertebrates and PFS possibly induced upward migration of altitudinal migrants and vice versa. AH possibly only played a minor role in influencing altitudinal migration, since it exhibited no significant correlation with the MNI. Furthermore, we found that the upward migration temperature range of altitudinal migrants ranged between 9.8°C and 13.9°C during spring and the downward migration temperature range ranged between 12.2°C and 7.9°C during autumn. In conclusion, our study and several other studies revealed that the same environmental factors influenced the altitudinal migration patterns of birds in the Hengduan Mountains.

Assessment of High-Severity Post-Fire Soil Quality and Its Recovery in Dry/Warm Valley Forestlands in Southwest China through Selecting the Minimum Data Set and Soil Quality Index

Recurrent wildfires can negatively affect soil quality, and post-fire soil quality recovery is critical for maintaining sustainable ecosystem development. The objective of this study was to evaluate the changes and recovery of soil properties and soil quality in the forests of dry/warm river valleys in southwest China after disturbance by high-severity fires. In this study, the impact of fire on soil properties and soil quality was investigated for three years post-fire. Unburned forest land with a similar natural environment compared to the fire area was used as a control. Soil samples were collected from three different depths of 0–10 cm, 10–20 cm, and 20–30 cm, respectively. Principal component analysis (PCA) combined with the Norm value was used to select the minimum data set (MDS), thus calculating the soil quality index (SQI). The results showed that the soil properties changed significantly after high-severity fires. On average, soil bulk density (0.91 g/cm3, p = 0.001), total nitrogen (0.12 g/kg, p = 0.000), total phosphorus (0.10 g/kg, p = 0.000), and total potassium (5.55 g/kg, p = 0.000) were significantly lower in the burned areas than in the unburned areas at the first sampling. These indicators increased in the following three years but still did not recover to unburned levels. Compared with the above indicators, soil porosity and organic matter increased post-fire, but gradually decreased over time. Soil clay, geometric mean diameter, and total potassium were included in the MDS. The SQI was ranked as unburned > 3 years > 2 years > 1 year > 6 months. The SQI was significantly (p = 0.001) reduced six months post-fire by an average of 36%, and, after three years of recovery, the soil quality of the post-fire areas could be restored to 81% of soil in unburned areas. Apparently, high-severity fires caused changes in soil properties, thereby significantly decreasing soil quality. Soil quality gradually improved with increasing restoration time. However, the complete recovery of soil quality post-fire in forest land in the dry/warm river valley will take a longer time.

Chromosome‐level genome assembly of a rare karst‐growing Rhododendron species provides insights into its evolution and environmental adaptation

AbstractRhododendron is a significant plant genus, with over 600 identified species in China. The subgenus Hymenanthes holds the largest number of Rhododendron germplasms and showcases strong environmental adaptability. However, there remains a lack of understanding regarding Rhododendron's evolution and environmental adaptations. Rhododendron bailiense Y.P.Ma, C.Q.Zhang & D.F.Chamb., an exceedingly rare species, thrives in the alkaline karst landforms of Guizhou, southwest China, different from the typical growing environment of other Rhododendron species. In this study, we present a chromosome‐level genome assembly of R. bailiense, revealing a genome size of 923.3 Mb, a contig N50 of 24.5 Mb, and a total of 47 567 predicted genes. An evolutionary analysis indicated that R. bailiense diverged from its ancestors prior to the other subgenus Hymenanthes rhododendrons, with the expanded and contracted genes being notably enriched in “stress response” and “growth,” respectively. Rhododendron bailiense is predominantly found on limestone soil in the mountains of Guizhou, with only two wild populations known. The genome of R. bailiense contained a high copy number of ankyrin repeat (ANK) and Ca2+‐ATPase (CAP) genes, primarily involved in Ca2+ transport, shedding light on how R. bailiense copes with karst high‐calcium stress. In contrast, the structures of the ANKs displayed unique characteristics, while the CAPs showed conservatism. The R. bailiense genome provides new insights into the adaptation and evolutionary history of Rhododendron plants in karst environments, potentially offering valuable information for adaptive breeding and ecological enhancement in such challenging settings.

Altitudinal Variation in Soil Acid Phosphomonoesterase Activity in Subalpine Coniferous Forests in China

Studying the altitudinal variation and driving factors of soil acid phosphomonoesterase (ACP) activity in subalpine regions is crucial for understanding nutrient cycling processes within mountainous ecosystems. This study focused on fir (Abies fabri (Mast.) Craib) forests located at three altitudes (2781 m, 3044 m, and 3210 m) on the eastern slope of Mt. Gongga in southwest China. We measured soil ACP activity alongside soil climate, nutrients, and microorganisms at various depths and elevations to investigate how these factors influence ACP activity. The results indicated that in the organic matter horizons (Oe and Oa horizons), ACP activity gradually decreased with elevation. However, the surface mineral horizon (A horizon) did not show a decline in ACP activity with increasing elevation, which could be attributed to significantly lower ACP activity recorded at the 2781 m sample site compared to the 3044 m site. Variance partitioning analysis revealed that among soil climate, nutrients, and microorganisms, soil nutrients had the most substantial impact on ACP activity across all horizons, with a particularly high contribution of 89.4% observed in the A horizon. Random forest model analysis further demonstrated that soil total carbon (TC) played a crucial role in determining ACP activity in the Oe and Oa horizons, with importance values of 8.5% and 7.3%, respectively. Additionally, soil total nitrogen (TN) was identified as the primary factor influencing ACP activity in the A horizon, with an importance value of 12.6%. Furthermore, soil ACP activity was positively regulated by the soil TC:TP and TN:TP ratios, indicating a stoichiometric control of ACP activity in the Abies fabri (Mast.) Craib forests on Mt. Gongga.

Understanding Poverty Alleviation in Rural China: The Role of Policy Brokers

ABSTRACTChina eradicated rural extreme poverty in 2020 after an 8‐year campaign that combined endogenous economic development involving local people with social assistance. Ethnographic research in a village in southwest China reports township officials, under‐resourced and pressed by higher tiers of government to meet the poverty‐eradication target, commissioning an entrepreneur as a policy‐broker. The latter established enterprises nominally to provide local employment, while seeking profitability from their investment. Prioritising poverty eradication over sustainability, government subsidies were employed to engineer income transfers lifting villagers out of poverty by the target date. Thereafter, transfers of income from the enterprises to impoverished people were at best irregular. The experience highlights the distorting effect of policy targets and the limits to endogenous development undertaken under time–pressure with villagers neither consulted nor benefiting from new employment.

Change in Fractional Vegetation Cover and Its Prediction during the Growing Season Based on Machine Learning in Southwest China

Fractional vegetation cover (FVC) is a crucial indicator for measuring the growth of surface vegetation. The changes and predictions of FVC significantly impact biodiversity conservation, ecosystem health and stability, and climate change response and prediction. Southwest China (SWC) is characterized by complex topography, diverse climate types, and rich vegetation types. This study first analyzed the spatiotemporal variation of FVC at various timescales in SWC from 2000 to 2020 using FVC values derived from pixel dichotomy model. Next, we constructed four machine learning models—light gradient boosting machine (LightGBM), support vector regression (SVR), k-nearest neighbor (KNN), and ridge regression (RR)—along with a weighted average heterogeneous ensemble model (WAHEM) to predict growing-season FVC in SWC from 2000 to 2023. Finally, the performance of the different ML models was comprehensively evaluated using tenfold cross-validation and multiple performance metrics. The results indicated that the overall FVC in SWC predominantly increased from 2000 to 2020. Over the 21 years, the FVC spatial distribution in SWC generally showed a high east and low west pattern, with extremely low FVC in the western plateau of Tibet and higher FVC in parts of eastern Sichuan, Chongqing, Guizhou, and Yunnan. The determination coefficient R2 scores from tenfold cross-validation for the four ML models indicated that LightGBM had the strongest predictive ability whereas RR had the weakest. WAHEM and LightGBM models performed the best overall in the training, validation, and test sets, with RR performing the worst. The predicted spatial change trends were consistent with the MODIS-MOD13A3-FVC and FY3D-MERSI-FVC, although the predicted FVC values were slightly higher but closer to the MODIS-MOD13A3-FVC. The feature importance scores from the LightGBM model indicated that digital elevation model (DEM) had the most significant influence on FVC among the six input features. In contrast, soil surface water retention capacity (SSWRC) was the most influential climate factor. The results of this study provided valuable insights and references for monitoring and predicting the vegetation cover in regions with complex topography, diverse climate types, and rich vegetation. Additionally, they offered guidance for selecting remote sensing products for vegetation cover and optimizing different ML models.

A study on the hepatic response to heat stress in Gymnocypris eckloni through an approach combining metabolomic and transcriptomic profiling

Gymnocypris eckloni, an economically important cold-water fish widely cultivated in southwest China, is at increased risk of prolonged exposure to heat stress owing to persistent high temperatures in summer, extreme climate changes, and expansion of factory farming. In this study, G. eckloni was subjected to both chronic and acute heat stress, with subsequent analysis focusing on changes in the pathological and physiological characteristics and transcriptomic and metabolic responses of the liver to high temperature. The results revealed heat stress-induced damage to liver tissues, lipid accumulation and mitochondrial abnormalities in hepatocytes, and an increased number of apoptotic cells, with the damage being more severe under acute heat stress conditions. Assessment of biochemical indices showed that the antioxidant enzyme catalase (CAT) was activated in response to oxidative stress and energy demands increased following heat stress. Transcriptomic analysis showed significant enrichment in the protein processing in the endoplasmic reticulum pathway, along with upregulation of key genes associated with protein degradation (hsp40, hsp70, hsp90, ero1l, and pdia4) and activation of the unfolded protein response (UPR), which effectively reduces or clears the accumulation of misfolded proteins to combat stress. Most identified differential metabolites were associated with amino acid and lipid metabolism under heat stress. Notably, integrated transcriptomic and metabolomic analysis suggested that tryptophan metabolism played an important role in the adaptation of G. eckloni to chronic heat stress. These findings improve the understanding of the mechanisms through which G. eckloni adapts to high temperatures, providing a valuable foundation and novel avenues for developing strategies to alleviate the effects of heat stress and improve the outcomes of aquaculture.

Attribution of climate change and human activities to spatiotemporal changes of ecological service value in Yunnan Province of China

Quantifying the influence of climate change and human activities on spatiotemporal changes of regional ecological service value (ESV) can provide key information for regional ecosystem protection. However, few studies have distinguished the contributions of climate change and human activities to the total ESV. In this study, Yunnan Province in Southwest China with high biodiversity and ESV was selected as a representative region for the attribution analysis of ESV changes. The Carnegie-Ames Stanford Approach (CASA) was used to calculate the vegetation net primary productivity (NPP), and improved equivalent factor method was used to calculate ESVs of different ecosystem service functions directly from NPP. Then, the multi-factor attribution analysis method was used to quantify the contribution rates of climate change and human activities to changes in ESV. Results show that the ESV in Yunnan Province increased by 12.9 % in 2000–2019 compared to 1980–1999 without considering economic development. Land use and cover change (LUCC) is the main cause for the increase in ESV with the contribution rate of 92.3 %, while that of climate change is only 7.7 %. Major components of ESV change are ESV changes in forests, grasslands, and farmland, which are all mainly caused by LUCC with the contribute rates of over 80 %. ESVs in different cities differ greatly, where the ESV and ESV per unit area in Pu'er City are 5.3 and 2.6 times as those in Zhaotong City, respectively. LUCC is also the main cause of ESV changes in all cities, with contributions rates generally exceeding 80 %. When considering economic development, the ESV in Yunnan has increased by 336.2 % in these two periods. Contribution rate of economic development to ESV increase in Yunnan is 80.3 %, while that of climate change and LUCC is only 19.7 %. The speed of ecological construction in Yunnan Province is far slower than that of economic development, and appropriate measures should be taken to improve the ecological services in the future.

Knowledge Mapping Analysis of Karst Rocky Desertification Vegetation Restoration in Southwest China: A Study Based on Web of Science Literature

Knowledge Mapping Analysis of Karst Rocky Desertification Vegetation Restoration in Southwest China: A Study Based on Web of Science Literature

Manganese(III) dominants the mobilization of phosphorus in reducing sediments: Evidence from Aha reservoir, Southwest China

Eutrophication has become one of the greatest threats to aquatic ecosystems. The release of phosphorus (P) from sediments exerts a critical role on eutrophication level. Both manganese (Mn) and iron (Fe), sensitive to redox conditions, own strong affinity for P. Numerous works have demonstrated that Fe was a key factor to drive P cycle in sediments. However, the role of Mn on P mobilization remains largely unexplored. Herein, the mechanism of P mobilization driven by Mn were investigated in a seasonal anoxic reservoir. Diffusive gradients in thin films (DGT) results, from both field investigations and laboratory incubations, showed P was synchronously distributed and significantly positive correlated (r2 ≥ 0.40, p < 0.01) with Mn, suggested that P cycle was associated with Mn. X-ray photoelectron spectroscopy (XPS) results showed that in the outer layers at the top 1 cm sediment pellet the contents of Mn and P occurred significantly synchronize changed, while that of Fe remains virtually unchanged when oxygen conditions changed. This demonstrated that Mn is likely to be the key factor affect P cycle. Most importantly, the relative content of Mn(III) changed the most (≈20 %) interpreted that Mn(III) is the key Mn species dominants the P mobilization. Furthermore, Dual-Beam scanning electron microscope (DB-SEM) maps clearly showed the co-enrichment of P and Mn in oxic sediments, confirmed P was mainly hosted by Mn minerals. In contrast, the random distributions and weak or negative correlations between P and Fe implied that P cycle was decouple with Fe, this resulted from that Fe was almost deposited as inert Fe fractions (>99.2 %) in reducing sediments. This study significantly expanded our knowledge on the geochemical behavior of P influenced by Mn in aquatic sediments.

What caused the lag between oxygen-18 and deuterium excess in atmospheric vapor and precipitation during the earlier summer season in southwest China?

A combined interpretation of oxygen-18 (δ18O) and deuterium excess (d-excess) in various archives in the Indian monsoon-dominated region may add value to the isotopic climate significance. Yet, coupling water δ18O and d-excess together is rarely discussed. Here, we present measurements for both δ18O and δ2H in water vapor and precipitation samples collected in the Nujiang River valley, an important moisture corridor for the Indian monsoon in southwestern China, aiming for an improved understanding of the hydrological cycle on seasonal scales. The observation found a significant drop occurred in the earlier summer season for δ18O and d-excess in vapor and precipitation. However, an approximately one-month lag between vapor δ18O and vapor d-excess is observed in seasonal variations, revealing different drivers for the seasonal patterns of vapor d-excess and δ18O. Spatial correlation analysis found that d-excess is mainly modulated by the relative humidity over the core moisture source over the Bay of Bengal (BOB), while the sharp decrease of vapor δ18O corresponds to the onset of the Indian summer monsoon associated with large-scale convective activities, which significantly depleted the vapor heavy isotopes. The finding of the phase difference in the seasonal isotope signals and the underlying mechanism will benefit the study in particularly using both δ18O and d-excess for an improved understanding of the hydrological processes in the Indian monsoon-dominated region, and will provide new insight into studies of paleoclimate rebuilding by using isotope-based proxy as well.

Transactivation DNA-binding protein-related genes were associated with salivary gland injury in primary Sjögren syndrome.

The purpose was to identify transactivation DNA-binding protein-related genes in salivary gland injury in primary Sjögren syndrome (pSS) in southwest China. We downloaded the datasets of GSE7451, GSE23117, and GSE40611. In order to screen the candidate genes, 2 kinds of machine learning algorithms were used. We collected blood from 28 patients and 20 controls to verify the expression of candidate genes using quantitative real-time polymerase chain reaction. The receiver operating characteristic curve was used to evaluate the diagnostic efficiency. Correlations between candidate genes and immune cells were examined. A total of 31 differentially expressed genes were obtained. Through different algorithms, 6 genes including IFIT1, CSF2RB, TRIM22, PPM1H, VAMP7, and C21orf2 were getted. Validation results suggested that the expression of CSF2RB, VAMP7, IFIT1, C21orf2, and TRIM22 was significantly increased in pSS. The area under the curve of CSF2RB was 0.937 and that of TRIM22 was 0.915. Immune infiltration analysis showed that the percentage of activated mast cells was lower than the controls (P = .025). Correlation analysis suggested that CSF2RB was associated with immune cell infiltration. The expression of CSF2RB was significantly upregulated, which could be related to the increase of γδ T cells. We revealed that CSF2RB could be the candidate gene of pSS. CSF2RB was involved by regulating various immune cells. The expression of CSF2RB was significantly upregulated, which was related to the increase of γδ T cells.

Characterizing urban heat islands in karst areas-the case of Kunming and Guiyang in Southwest China

Characterizing urban heat islands in karst areas-the case of Kunming and Guiyang in Southwest China