Southern Regions Of China Research Articles

Insights into civil aviation emissions in China: Analysis of an emission inventory of air pollutants and the ChinaHighAirPollutants (CHAP) dataset

The emissions from the civil aviation sector are a significant source of CO2 and air pollutants, which represent a serious threat to ambient air quality and public health. To gain a deeper understanding of civil aviation airport emissions, it is imperative to develop a precise and comprehensive emission inventory of China's civil aviation airports. However, there are limited studies dedicated to analyzing and verifying the accuracy and completeness of China's civil aviation emission inventory. Here, this study explored pollution characteristics from temporal trends and spatial distribution perspectives based on a previously developed 2019–2020 high-resolution air pollution and CO2 emission inventory of the landing and take-off (LTO) cycle of civil aviation airports in China and the ChinaHighAirPollutants (CHAP) dataset. Besides, this study established an empirical model to evaluate the relationship between the air pollutant emissions of China's civil aviation sector in 2019–2020 and the pollutant concentration from the CHAP dataset. Compared to those in 2019, the total NOx, CO, PM, and SO2 emissions during the LTO phase in China's civil aviation sector in 2020 decreased by 14.29%–24.32%, and the average concentrations of NO2, CO, PM10, and SO2 in 2020 decreased by 6.33%–9.45%. The eastern, central, and southern regions of China are characterized by high emissions of pollutants, a phenomenon closely related to the economic prosperity and tourism development in these areas. They tend to boast higher route densities, increasing air transport activity and consequently resulting in elevated emissions. In addition, NOx had the highest correlation coefficient in the empirical model, with a correlation coefficient of 0.603 in 2019. Our findings provide new insights into civil aviation emissions in China from the analysis of the emission inventory of air pollutants and the CHAP dataset and provide a new method for verifying the accuracy and completeness of China's civil aviation emission inventory.

Dense infraspecific sampling reveals cryptic differentiation in the enigmatic hemiparasitic love vine Cassytha filiformis (Lauraceae)

AbstractSpecies delimitation remains a challenge worldwide, especially in highly diverse tropical and subtropical regions. Here, we use an integrative approach that combines morphology, phylogenomics, and species distribution modeling (SDM) to clarify the cryptic differentiation within the enigmatic hemiparasitic love vine Cassytha filiformis (Lauraceae) in China and adjacent regions. We generated complete plastid genomes and nuclear ribosomal sequences for diverse samples from across the species range and compared results with previously published plastid data, recovering two well‐supported monophyletic clades. Further, the analysis revealed significant differences in two morphological characters and SDM, indicating distinct environmental factors influencing their distributions. Fossil‐calibrated analyses to estimate the origins and diversification patterns for the cryptic species gave divergence age estimates corresponding to the Oligo‐Miocene; a period of new ecological opportunities associated with the prevailing East Asian monsoon. Multivariate analyses support the conclusion that southern China and adjacent regions have a different, previously unknown, cryptic lineage of C. filiformis. Our study highlights the importance of using multivariate approach to characterize plant species, as well as the significant role that past climatic changes have played in driving speciation in parasitic plants in tropical and subtropical zones.

Modelling hydrologic processes of a karst region in Southern China using coupled hydrological models

ABSTRACT In the karst area, the epikarst increases the infiltration of rainfall and the depressions and conduits make water exchange frequently between surface rivers and karst aquifers. To improve simulation accuracy, we proposed the Soil and Water Assessment Tool-Genetic Algorithm-Back Propagation (SWAT-GA-BP) model. Also, the SWAT-tank model was created to elaborate the runoff processes in different karst systems. Furthermore, we designed three scenarios to study the influence of land use changes on runoff. The Zuo River Basin was selected as a case study. Compared to SWAT, the determination coefficient of the SWAT-GA-BP increased by 4.8% and the Nash-Sutcliffe efficiency increased by 4.9%; the rapid flow accounted for more than 50% of the total runoff, and the slow flow for less than 10%; the contribution of the land use changes was 10.80% from 2008 to 2012 and 5.57% from 2013 to 2017. Therefore, the effect of land use change on runoff should not be ignored.

Evolution of rates, patterns, and driving forces of green eco-spaces in a subtropical hilly region

Monitoring ecological resource change in mountainous and hilly areas (MHAs) is vital for theoretical and practical advancements of ecological resource utilization and management in complex ecosystems. The factors driving structural and functional changes in green eco-spaces (GES) in these areas are complex and uncertain, with notable spatial scale effects. However, analyzing the multi-scale driving mechanisms of ecological and socioeconomic factors at a fine spatiotemporal scale presents significant challenges. To address these challenges, we analyzed dynamic changes in GES and eco-socio-economic development in Shanghang County, a typical mountainous region in southern China. We used multiple linear regression and multi-scale geographically weighted regression model to identify key factors driving GES changes and their multi-scale effects at both global and local levels. Over the past two decades, the GES area in the study area has exhibited a consistent pattern of decline, characterized by phases of gradual decline (2000–2005), sharp decline (2005–2009), slow decline (2009–2019). Key global factors driving GES changes included elevation (ELE), slope (SLOPE), population density (PD), distance to settlements (SETTLE), and distance to administrative centers (ADMIN). These factors exhibited significant spatial heterogeneity and multi-scale effects on GES changes. Specifically, SETTLE, PD, SLOPE, and ELE consistently drove GES changes at the local level, while ADMIN only showed significant localized effects during 2005–2009. The synergy between SETTLE and SLOPE had a considerable impact on GES changes, increasing over time, whereas ELE and PD demonstrated a consistent trade-off effect. These findings provide detailed spatiotemporal insights into the driving mechanisms of natural ecological resources, offering crucial guidance for environmental management, land source management, regional economic development, and biodiversity conservation in Shanghang and analogous subtropical hilly regions worldwide.

First Report of Colletotrichum cordylinicola Causing Anthracnose on Cordyline fruticosa in China.

Cordyline fruticosa is a shrub plant, commonly used in landscape, and distributed in the tropical regions of southern China. In September 2022, anthracnose symptoms were found on this species in Nanning, Guangxi, China. The disease incidence was between 30% to 80% and disease severity was 10% to 30% in five surveyed planting areas. The symptoms initially appeared as small, round, brown spots on leaves. As the disease developed, the lesions turned gray-white with brown borders and yellow halos. Some spots coalesced into larger irregular shapes and even leading to leaf blight. Small segments of the diseased tissues (3×3 mm) were cut from the leaves, surface-sterilized by dipping in a 1% sodium hypochlorite solution for 1 min, rinsed three times with sterile distilled water, and plated on potato dextrose agar (PDA). These plates were incubated at 28°C in the dark for 5 days. Ten fungal isolates with similar morphology were consistently isolated from these diseased tissues. The colonies on PDA were initially white with sparse aerial mycelia and turned pale orange with abundant orange conidial masses on the center after 8 days of culture. The reverse color was pale orange. No sclerotia or setae were found in culture. Conidia were single-celled, hyaline, straight, cylindrical with round ends, and 12.2 to 17.8 µm long (mean 14.9 µm) and 3.9 to 7.3 µm wide (mean 4.8 µm, n=50). The morphological characteristics of these isolates were similar to the Colletotrichum cordylinicola (Sharma et al., 2014). Genomic DNA of two isolates Z3 and Z4 generated from monospore culture was extracted using a fungal DNA extraction kit (Solarbio, Beijing, China). Partial sequences of internal transcribed spacer (ITS), partial actin (ACT), chitin synthase (CHS-1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and beta-tubulin (TUB2) were amplified using the primer pairs ITS1/ITS4, ACT-512F/ACT-783R, CHS-79F/CHS-345R, GDF1/GDR1, and BT2A/BT2B (Lin et al., 2022), respectively. All the sequences (GenBank accession nos. OQ509909, OQ509910, OQ658690, OQ658691, and OK649310 to OK649314) showed 99% to 100% identity with those of C. cordylinicola in GenBank database. A phylogenetic tree based on concatenated sequences of ITS, ACT, CHS-1, TUB, and GAPDH using maximum likelihood analysis by MEGA X software revealed that Z3 and Z4 clade with reference strains of C. cordylinicola (OJX010226 and MK935473). Based on morphological observation and multi-gene sequence analysis, the isolates were identified as C. cordylinicola (Phoulivong et al., 2010). To assess their pathogenicity, conidial suspensions (106 conidia/ml) of C. cordylinicola were inoculated onto 10 healthy living leaves wounded by slight puncturing (10 μl/wounded spot). Control leaves were treated with sterile water. All inoculated and control plants were maintained under high relative humidity (~90%) and 28℃ in a climate chamber. After 8 days, all the inoculated leaves showed brown lesions resembling natural symptoms, whereas the control group remained symptom-free. The same fungus was re-isolated from the symptomatic leaves, thus completing Koch's postulates. C. cordylinicola is a species of the C. gloeosporioides complex (Weir et al., 2012). It has been reported to cause anthracnose on C. fruticosa in USA and Thailand (Phoulivong et al., 2010; Sharma et al., 2014). To our knowledge, this is the first report of C. cordylinicola causing anthracnose on C. fruticosa in China. Knowing the causal agent is essential to control the serious disease effectively.

A Short-Term Traffic Flow Prediction Method for Airport Group Route Waypoints Based on the Spatiotemporal Features of Traffic Flow

To fully leverage the spatiotemporal dynamic correlations in air traffic flow and enhance the accuracy of traffic flow prediction models, thereby providing a more precise basis for perceiving congestion situations in the air route network, a study was conducted on a traffic flow prediction method based on deep learning considering spatiotemporal factors. A waypoint network topology graph was constructed, and a neural network model called graph convolution and self-attention-based long short-term memory neural network (GC-SALSTM) was proposed. This model utilized waypoint flow and network efficiency loss rate as input features, with graph convolution extracting spatial features from the waypoint network. Additionally, a long short-term memory network based on a self-attention mechanism was used to extract temporal features, achieving accurate prediction of waypoint traffic. An example analysis was performed on a typical busy sector of airports in the Central and Southern China region. The effectiveness of adding the network efficiency loss rate as an input feature to improve the accuracy of critical waypoint traffic prediction was validated. The performance of the proposed model was compared with various typical prediction models. The results indicated that, with the addition of the network efficiency loss rate, the root mean square error (RMSE) for eight waypoints decreased by more than 10%. Compared to the historical average (HA), autoregressive integrated moving average (ARIMA), support vector regression (SVR), long short-term memory (LSTM), and graph convolution network and long short-term memory network (GCN-LSTM) models, the RMSE of the proposed model decreased by 11.78%, 5.55%, 0.29%, 2.53%, and 1.09%, respectively. This suggests that the adopted network efficiency loss rate indicator effectively enhances prediction accuracy, and the constructed model exhibits superior predictive performance in short-term waypoint traffic forecasting compared to other prediction models. It contributes to optimizing flight paths and high-altitude air routes, minimizing flight delays and airborne congestion to the greatest extent, thus enhancing the overall efficiency of the entire aviation system.

Erosion processes and sediment source tracing on heterogeneous slopes in the red soil region of southern China

AbstractUnderstanding erosion, sediment sources and the spatial distribution along heterogeneous slopes is essential for soil and water conservation. In this study, soils derived from nodular limestone, mud‐like limestone and limestone breccia (abbreviated as SMTL, SMDL and SLBC, respectively) were utilized to establish artificial homogeneous and heterogeneous slopes. The homogeneous slopes MTL, MDL and LBC represent SMTL‐, SMDL‐ and SLBC‐filled‐ slopes, respectively. The heterogeneous slopes were abbreviated as MTL/MDL, MDL/LBC and LBC/MTL. Rare earth elements (REEs; lanthanide, cerium and ytterbium) were used to tag soils on the upper and lower slope sections to track sediment transport and deposition. The results showed that for homogeneous slopes, the LBC slope was the most severely eroded, followed by the MDL and MTL slopes. For heterogeneous slopes, the order of erosion was LBC/MTL > MTL/MDL > MDL/LBC. Upslope sections contributed a sizable portion of the total sediment yield, ranging from 51% to 79%. Over time, the difference in the sediment contribution between the upslope and downslope regions decreased and reached equilibrium. Runoff rates on heterogeneous slopes demonstrated an inverse function (R2 > 0.75) in contrast to a logarithmic distribution (R2 > 0.87) on homogeneous slopes. Heterogeneous slopes displayed minimal intersegment variation and the absence of a consistent ordering of the magnitude of hydraulic parameters. Conversely, the hydraulic parameters of homogeneous slopes were consistently ordered across the slope sections. For sediment transport, all slopes exhibited suspension‐dominated flow with percentages greater than 89%. However, the particle size distribution of the sediment of heterogeneous slopes exhibited greater diversity and complexity because of the coexistence of distinct soils. These findings underscore the importance of customized strategies for soil and water conservation in environments characterized by diverse soil parent materials.

Unveiling causal connections: Long-term particulate matter exposure and type 2 diabetes mellitus mortality in Southern China

Evidence of the potential causal links between long-term exposure to particulate matters (PM, i.e., PM1, PM2.5, and PM1–2.5) and T2DM mortality based on large cohorts is limited. In contrast, the existing evidence usually suffers from inherent bias with the traditional association assessment.A prospective cohort of 580,757 participants in the southern region of China were recruited during 2009 and 2015 and followed up through December 2020. PM exposure at each residential address was estimated by linking to the well-established high-resolution simulation dataset. Hazard ratios (HRs) were calculated using time-varying marginal structural Cox models, an established causal inference approach, after adjusting for potential confounders.During follow-up, a total of 717 subjects died from T2DM. For every 1 μg/m3 increase in PM2.5, the adjusted HRs and 95% confidence interval (CI) for T2DM mortality was 1.036 (1.019–1.053). Similarly, for every 1 μg/m3 increase in PM1 and PM1–2.5, the adjusted HRs and 95% CIs were 1.032 (1.003–1.062) and 1.085 (1.054–1.116), respectively. Additionally, we observed a generally more pronounced impact among individuals with lower levels of education or lower residential greenness which as measured by the Normalized Difference Vegetation Index (NDVI). We identified substantial interactions between NDVI and PM1 (P-interaction = 0.003), NDVI and PM2.5 (P-interaction = 0.019), as well as education levels and PM1 (P-interaction = 0.049).The study emphasizes the need to consider environmental and socio-economic factors in strategies to reduce T2DM mortality. We found that PM1, PM2.5, and PM1–2.5 heighten the peril of T2DM mortality, with education and green space exposure roles in modifying it.

Evolutionary patterns and influencing factors of relationships among ecosystem services in the hilly red soil region of Southern China.

As a crucial ecological protection area in China, the Southern hilly red soil region is characterized by uneven spatial and temporal distribution of ecological landscape elements, unpredictable and changeable interrelationships between them, diversified driving factors, and lack of comprehensive consideration of ecosystem services. In order to better understand the interaction between ecosystem services, restore regional ecology, and promote sustainable development, the evolution law and influencing mechanism of ecosystem services and their driving factors are quantitatively analyzed in the study. Based on simulations of different ecosystem services from 2000 to 2020, their spatial and temporal changes and the contributions of main drivers are quantified, their trade-offs and synergies are analyzed, and the changing rules under the influence of natural factors and socioeconomic factors are explored. The results show that (1) the crop production significantly increases in the southwest and north regions, the habitat quality decreases in urban and coastal areas, and the soil retention and water yield show an increasing trend from west to east. (2) Land use/cover is the main driver of carbon storage and habitat quality variation, and precipitation is an important driver of water yield spatial variation. (3) The crop production and the other four ecosystem services show a trade-offs relationship, and the relationship between supporting services and regulating services is the synergetic. (4) The altitude weakens the synergistic relationship between soil retention and habitat quality/carbon storage, while it enhances the synergistic relationship between soil retention and water yield. Driven by precipitation factors, ecosystem services related to water yield have significant differences in the change. The population density enhances the trade-offs of crop production and soil retention, as well as the synergistic relationship between soil retention and habitat quality/carbon storage. In different land use/cover (LULC), the influence of urban land on ecosystem services relationship change is more obvious. Overall, this study can provide scientific bases and policy suggestions for ecosystem protection/restoration in the red soil region of Southern China, which has an important theoretical and practical significance.

Effects of multi-year droughts on the precipitation-runoff relationship: An integrated analysis of meteorological, hydrological, and compound droughts

Multi-year droughts cause severe water scarcity, ecosystem collapse, and significant socio-economic losses. Understanding the impact of these droughts on the precipitation-runoff (PR) relationship is crucial for managing water resources and mitigating drought-related damage. However, previous research focuses mainly on the influence of multi-year meteorological droughts on the PR relationship, neglecting multi-year hydrological droughts and their compound effects. Studies also generally overlook the speed and volume of precipitation-to-runoff conversion, considering only the quality of PR relationship. Furthermore, there is a lack of effective simulation methods using the intensity of multi-year droughts to understand the PR relationship. To address these gaps, this study defines multi-year compound droughts and employs three key parameters, namely, the determination of coefficient (R2), linear regression slope, and runoff coefficient, to assess the impact of multi-year droughts on changes in the PR relationship's quality, precipitation-to-runoff conversion speed, and runoff volume. A random forest model is then employed to simulate these parameters based on the intensity of multi-year droughts. Case studies conducted in three basins within the arid-semiarid region of northern China as well as in three basins in the humid region of southern China reveal that multi-year droughts result in water shortages and have a significant impact on the PR relationship. Among different types of multi-year droughts, hydrological droughts have the greatest impact on the PR relationship, followed by compound and meteorological droughts, respectively. During meteorological, hydrological, and compound drought periods, the average rainfall (runoff) is lower by 26 – 30% (33 – 58%), 18 – 28% (36 – 60%), and 18 – 26% (30 – 58%) respectively compared to non-drought periods. Furthermore, the PR relationship remains stable in the rivers of the humid region in southern China. In contrast, the Loess Plateau region in northern China exhibits a substantial decrease in both the speed and volume of precipitation-to-runoff conversion. Interestingly, this decline is not accompanied by a significant increase in the R2 of the PR relationship. The random forest approach effectively simulates key parameters of the PR relationship based on the intensity of multi-year droughts. These findings hold crucial implications for the long-term regional water resource planning.

Interannual Monitoring of Cropland in South China from 1991 to 2020 Based on the Combination of Deep Learning and the LandTrendr Algorithm

Timely and accurate acquisition of spatial distribution and changes in cropland is of significant importance for food security and ecological preservation. Most studies that monitor long-term changes in cropland tend to overlook the rationality in the process of cropland evolution, and there are conflicts between the interannual cropland data, so they cannot be used to analyze land use change. This study focuses on the rationality of annual identification results for cropland, considering the long-term evolution and short-term variations influenced by natural environmental changes and human activities. An approach for annual monitoring of cropland based on long time series and deep learning is also proposed. We acquired imagery related to cropland’s vegetation lush period (VLP) and vegetation differential period (VDP) from Landsat images on the Google Earth Engine (GEE) platform and used the ResUNet-a structural model for training. Finally, a long-time-series cropland correction algorithm based on LandTrendr is introduced, and interannual cropland maps of Guangdong Province from 1991 to 2020 were generated. Evaluating the cropland monitoring results in Guangdong Province every five years, we found an overall accuracy of 0.91–0.93 and a kappa coefficient of 0.80–0.83. Our results demonstrate good consistency with agricultural statistical data. Over the past 30 years, the total cropland area in Guangdong Province has undergone three phases: a decrease, significant decrease, and stabilization. Significant regional variations have also been observed. Our approach can be applied to long-time-series interannual cropland monitoring in the southern regions of China, providing valuable data support for the further implementation of cropland protection.

First Report of Alternaria Leaf Spot Caused by Alternaria alternata on Ulmus parvifolia in Jiangsu, China.

Ulmus parvifolia Jacq. is an important tree with ornamental value, which is widely planted in Hebei and southern regions of China. In September 2022, a leaf spot symptom was observed on about approximately 20% U. parvifolia seedlings growing a tree farm (20000 m2) of Jiangsu Academy of Forestry (118°45'57.30″E, 31°51'27. 94″N). Gray to black spots appeared on leaves of seedlings. Five diseased leaves were collected from five different seedlings. The pieces were excised from the margins between healthy and diseased tissues, surface sterilized in 75% ethanol for 30 s and then in 1.5% NaClO for 90 s, rinsed three times in sterilized distilled water, plated on potato dextrose agar (PDA) and incubated at 25℃ in the darkness. Pure cultures were obtained by monosporic isolation. Six isolates with identical morphological features and the internal transcribed spacer (ITS) sequences were obtained (the isolate rate of 67%), and identified as Alternaria sp. A representative isolate, LY-1-1 was used for the further study. The colony of LY-1-1, growing on PDA was cotton-like and brown in color with gray-white aerial hyphae on their surfaces, and its reverse was dark grey. The conidia were ovate to pear-shaped, brown in color, with 1 to 4 transverse septa and 0 to 1 longitudinal septa, parietal cells extending into the beak, and measured 7.1 to 12.5×3.8 to 7.1 µm (n=35). These characteristics were consistent with the description of Alternaria sp. (Simmons 2007). The regions of ITS, large subunit ribosomal RNA (LSU), small subunit ribosomal RNA (SSU), anonymous region OPA10-2 genomic sequence (OPA10-2), Alternaria 1 major allergen (Alta1), glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and translation elongation factor 1-alpha (TEF1) genes (GenBank Accession No. OR047916, OR051904, OR047919, OR061065, OR061063, OR061064, and OR061062, respectively) were amplified (White et al. 1990; Woudenberg et al. 2015) and sequenced. These obtained sequences showed 99.86-100% similarity to the ITS (514/515 bp) of A. alternata isolate SPM-2 (OR378581), LSU (801/801 bp) of isolate B9 (OR366492), SSU (1019/1020 bp) of strain LSU0766 (MT000349), OPA10-2 (632/633 bp) of strain 19-1 (MN185000), Alta1 (470/470 bp) of strain CMML21-73 (OQ831518), GAPDH (177/177 bp) of isolate CS36-3 (KY814638), and TEF1 (240/240 bp) of isolate SY-6 (OP980553). A neighbor-joining phylogenetic tree was generated by combining all sequenced loci in MEGA7. The isolate LY-1-1 clustered in the A. alternata clade with 98% bootstrap support. Three 3-month-old U. parvifolia seedlings were wounded with a sterile needle and inoculated with 20 μL conidia suspension (1×106 spores/mL) on the left sides of leaves. Inoculation on the right side with 20 µL of sterile water was treated as a control. All inoculated plants were incubated in a greenhouse at 25℃, 80% relative humidity, and a 12-h light/dark cycle. The experiment was repeated three times. After 5 days of inoculation, typical gray to black spots were found on the left sides of all inoculated leaves, and the control did not have any leaf spot symptoms. Subsequently, the same fungus was reisolated and identified based on morphological and molecular traits, fulfilling Koch's postulates. The A. alternata has been reported to cause leaf spot on pecan (Wu et al. 2020), fruit spot on olive (Alam et al. 2019) and fruit rot on lychee (Alam et al. 2017). However, there are no other reports of A. alternata on U. parvifolia in the world. Thus, this study provides an important reference for the biology, epidemiology of A. alternata.

Antennal transcriptome analysis of Psyttalia incisi (silvestri) (Hymenoptera: Braconidae): identification and tissue expression profiling of candidate odorant-binding protein genes.

Olfaction plays an important role in host-seeking by parasitoids, as they can sense chemical signals using sensitive chemosensory systems. Psyttalia incisi (Silvestri) (Hymenoptera: Braconidae) is the dominant parasitoid of Bactrocera dorsalis (Hendel) in fruit-producing regions of southern China. The olfactory behavior of P. incisi has been extensively studied; however, the chemosensory mechanisms of this species are not fully understood. Bioinformatics analysis of 64,515 unigenes from the antennal transcriptome of both male and female adults P. incisi identified 87 candidate chemosensory genes. These included 13 odorant-binding proteins (OBPs), seven gustatory receptors (GRs), 55 odorant receptors (ORs), 10 ionotropic receptors (IRs), and two sensory neuron membrane proteins (SNMPs). Phylogenetic trees were constructed to predict evolutionary relationships between these chemosensory genes in hymenopterans. Moreover, the tissue expression profiles of 13 OBPs were analyzed by quantitative real-time PCR, revealing high expression of seven OBPs (1, 3, 6, 7, 8, 12, and 13) in the antennae. This study represents the first identification of chemosensory genes and the determination of their expression patterns in different tissues of P. incisi. These results contribute to a better understanding of the function of the chemosensory system of this parasitoid species.

"Iron Ion Relative Weathering Index": A New Index for Identifying the Weathering Degree in Red Sandstone.

The red bed region in west central and southern China is affected by hot and humid climate, where sandstone is intensely weathered. The weathered hazardous rocks seriously threaten the road and slope, making it challenging to protect the Danxia red bed. After considering the red sandstone's material composition and the local area's main weathering effects. We noticed that iron ions in red sandstone are susceptible to weathering, which leads to changes in the valence and content of iron ions. This study attempts to establish a new chemical weathering index called the "iron ion relative weathering index" (IRWI) to classify the weathering degree of red sandstone. This paper mainly explores the changes of physical characteristics (mineral composition, physical indicator, microstructure, and pore structure) from the surface to the interior of red sandstone in the actual environment and their correlation with IRWI. The study on the correlation between the physical indicators such as longitudinal wave velocity, resistivity, density, water absorption, and IRWI reveals that they have the same trends and are closely related to the weathering degree. The shallow weathering zone of Chishui red sandstone is divided into strong, medium, and slight weathering zones. Microscopically, the cementation and pore distribution of the red sandstone are consistent with the characteristics of the weathering zone. Therefore, IRWI not only is a reliable chemical quantitative method in indicating the weathering of red sandstone but also takes into account the controlling role of iron in the color development of red beds, which provides a new research idea for the quantitative identification of weathering degree and color mechanism of red sandstone.

Influence of tectonic preservation conditions on the nanopore structure of shale reservoir: A case study of Wufeng-Longmaxi Formation shale in western Hubei area, south China

Tectonism is one of the dominant factors affecting the shale pore structure. However, the control of shale pore structure by tectonic movements is still controversial, which limits the research progress of shale gas accumulation mechanism in the complex tectonic region of southern China. In this study, 34 samples were collected from two exploratory wells located in different tectonic locations. Diverse experiments, e.g., organic geochemistry, XRD analysis, FE-SEM, low-pressure gas adsorption, and high-pressure mercury intrusion, were conducted to fully characterize the shale reservoir. The TOC, Ro, and mineral composition of the shale samples between the two wells are similar, which reflects that the shale samples of the two wells have proximate pores-generating capacity and pores-supporting capacity. However, the pore characteristics of shale samples from two wells are significantly different. Compared with the stabilized zone shale, the porosity, pore volume, and specific surface area of the deformed zone shale were reduced by 60.61%, 64.85%, and 27.81%, respectively. Moreover, the macroscopic and fine pores were reduced by 54.01% and 84.95%, respectively. Fault activity and uplift denudation are not conducive to pore preservation, and the rigid basement of Huangling uplift can promote pore preservation. These three factors are important reasons for controlling the difference in pore structure between two wells shales. We established a conceptual model of shale pores evolution under different tectonic preservation conditions. This study is significant to clarify the scale of shale gas formation and enrichment in complex tectonic regions, and helps in the selection of shale sweet spots.

Comparative Analyses of Acacia Plastomes to Detect Mutational Hotspots and Barcode Sites for the Identification of Important Timber Species

The genus Acacia is a crucial source of industrial papermaking and timber, possessing significant economic value. Due to their nitrogen-fixing ability, rapid growth, and high tolerance to stress, Acacia species have become integral to short-term industrial timber forests, particularly in southern China and various other regions worldwide. Nevertheless, comparative genomic analyses of Acacia species remain limited, impeding the development of molecular markers for identifying and distinguishing between distinct Acacia species as well as distinguishing their wood counterparts from other tree species. To address this gap, we generated plastomic sequences from eight species commonly cultivated in Chinese plantation forests and compared them with existing data. Our findings revealed a generally conserved structure and gene content within the plastid genomes of Acacia. Notably, the dN/dS ratio of genes from distinct functional groups varied, particularly between ribosomal proteins and photosynthesis genes. Furthermore, phylogenetic analyses and sequence comparisons suggest that the introduction of Acacia to China may have been less diverse than previously thought or that interspecies introgression has occurred more frequently than previously documented. This study offers a valuable starting point for future research in this area and for improving timber quality through marker-assisted breeding.

Overexpression of vacuolar transporters OsVIT1 and OsVIT2 reduces cadmium accumulation in rice.

Excessive cadmium in rice grain in agricultural production is an important issue to be addressed in some southern regions of China. In this study, we constructed transgenic rice overexpressing OsVIT1 and OsVIT2 driven by 35S promoter in the cultivar ZH11. Compared with ZH11, OsVIT1 expression in leaves was significantly increased by 3-6.6 times and OsVIT2 expression in leaves was significantly increased by 2-2.5 times. Hydroponic experiments showed that overexpression of OsVIT1 and OsVIT2 increased the tolerance to Fe deficiency, significantly reduced Cd content in shoot and xylem sap, and had no effect on Cd tolerance in rice. Two years of field trials showed that the Fe content in the grain of OsVIT1 and OsVIT2 overexpressed materials was significantly reduced by 20-40% and the straw Fe content was significantly increased by 10-45%, and the grain Fe content distribution ratio was significantly decreased and the straw Fe distribution ratio was significantly increased compared with the wild type. The OsVIT1 and OsVIT2 overexpressed materials significantly reduced the Cd content of grain by 40-80% and the Cd content of straws by 37-77%, and the bioconcentration factor of Cd was significantly reduced in both grains and straw of OsVIT1 and OsVIT2 overexpressed materials. Overexpression of OsVIT1 and OsVIT2 did not affect the concentration of other metal ions in rice straw and grain. qRT-PCR analysis showed that the expression of the low affinity cation transporter OsLCT1 was significantly downregulated in the OsVIT1 and OsVIT2 overexpressed materials. In conclusion, overexpression of OsVIT1 and OsVIT2 reduced Cd accumulation in straw and grains, providing a strategy for Cd reduction in rice.

Intern-Nursing Students' Knowledge of Vascular Catheter-Associated Infections and Its Associated Factors: A Cross-Sectional Survey in China.

Medical personnel contact with the patient closely, and their knowledge of vascular catheter-associated infections (VCAIs) is closely related to the prevention of VCAIs. Researchers mainly pay attention to the VCAIs knowledge of doctors and nurses but rarely pay attention to the nursing students in the hospital internship stage. To investigate the current situation of knowledge of intern-nursing students in VCAIs, and analyze its influencing factors. 843 intern-nursing students were selected from 10 hospitals in five regions of eastern, western, southern, northern, and central China from June 26 to July 31, 2023, using a two-stage random sampling method. A self-designed questionnaire with good reliability and validity was used to investigate their knowledge of VCAIs, and t-test, multiple linear regression analysis, and Welch t-test were used to analyze the collected data by using SPSS Statistics 26.0 (IBM Corp., Armonk, NY). Intern nursing students' mean score of VCAIs knowledge was 48.66 (SD=15.77), with a score below 60 (unqualified) accounting for 75.4%, a score of 60-79 (qualified) accounting for 19.7%, a score of 80-89 (good) accounting for 3.6%, and a score of above 90 accounting for 1.3%. Students who attended VCAIs training three or more times had higher scores than those who did not attend training (B: 4.706, p=0.001), knowledge scores of students with a bachelor's degree or above were higher than those with junior college degree or below (B: 8.479, p<0.001), students who interned in tertiary hospitals had higher scores than those practicing in secondary hospitals (B:12.381, p<0.001) and scores of students in hospital training were significantly higher than study independently (B:4.116, p=0.007). Intern-nursing students have a relatively low level of knowledge about VCAIs. It is recommended to strengthen clinical systematic and standardized training, improve the knowledge mastery level of intern-nursing students, and enhance their ability to handle VCAIs.

Detection of Benggang in Remote Sensing Imagery through Integration of Segmentation Anything Model with Object-Based Classification

Benggang is a type of erosion landform that commonly occurs in the southern regions of China, posing significant threats to local farmland and human safety. Object-based classification (OBC) can be applied with high-resolution (HR) remote sensing images for detecting Benggang areas on a large spatial scale, offering essential data for aiding in the remediation efforts for these areas. Nevertheless, traditional image segmentation methods may face challenges in accurately delineating Benggang areas. Consequently, the extraction of spatial and textural features from these areas can be susceptible to inaccuracies, potentially compromising the detection accuracy of Benggang areas. To address this issue, this study proposed a novel approach that integrates Segment Anything Model (SAM) and OBC for Benggang detection. The SAM was used to segment HR remote sensing imagery to delineate the boundaries of Benggang areas. After that, the OBC was employed to identify Benggang areas based on spectral, geometrical, and textural features. In comparison to traditional pixel-based classification using the random forest classifier (RFC-PBC) and OBC based on the multi-resolution segmentation (MRS-OBC), the proposed SAM-OBC exhibited superior performance, achieving a detection accuracy of 85.46%, a false alarm rate of 2.19%, and an overall accuracy of 96.48%. The feature importance analysis conducted with random forests highlighted the GLDV Entropy, GLDV Angular Second Moment (ASM), and GLCM ASM as the most pivotal features for the identification of Benggang areas. Due to its inability to extract and utilize these textural features, the PBC yielded suboptimal results compared to both the SAM-OBC and MRS-OBC. In contrast to the MRS, the SAM demonstrated superior capabilities in the precise delineation of Benggang areas, ensuring the extraction of accurate textural and spatial features. As a result, the SAM-OBC significantly enhanced detection accuracy by 34.12% and reduced the false alarm rate by 2.06% compared to the MRS-OBC. The results indicate that the SAM-OBC performs well in Benggang detection, holding significant implications for the monitoring and remediation of Benggang areas.

Rice planting acceleration of the activation and loss of soil iron in the red soil region of southern China

Rice planting acceleration of the activation and loss of soil iron in the red soil region of southern China