Southeastern Coastal Area Of China Research Articles

The synchronized dynamic release behavior of microplastics during farmland soil erosion process

Microplastics (MPs) are widespread in farmland soil. However, the risks associated with their loss through soil erosion remain unknown. This study investigates the occurrence and behavior of MPs in farmland soil in a southeastern coastal area of China, focusing on their synchronized dynamic release during soil erosion scenarios. The results showed that the abundance of MPs in the tested farmland soil ranged from 2.40×104 to 1.04×105 items·kg-1. MPs predominantly appear as fragments and particles, with sizes concentrated between 30-100 μm. During the process of soil erosion, characterized by rapid soil subsidence, the amount of MPs released into water bodies initially decreases, averaging a reduction of 1.08×104 items·kg-1. This is followed by an average increase of 1.89×104 items·kg-1. The competition between the adsorption, collision, and sedimentation of soil particles and the desorption and release of settled particles, determines this behavior. This pattern is strongly related to the physicochemical properties and mechanical composition of the soil. Deep learning predictions revealed that, without external influences, 49.42% of MPs in farmland soil could be synchronously released into water bodies during erosion. The analysis shows that MPs exhibit dynamic behavior in time and space, posing serious threats to aquatic ecosystems. Controlling soil erosion in farmland is crucial for the source management of MP migration.

Hydrochemical insights, water quality, and human health risk assessment of groundwater in a coastal area of southeastern China.

Groundwater is a vital water supply worldwide, but its quality has gradually deteriorated with the development of society. In this study, a total of 40 groundwater samples were collected during the pre- and post-monsoon to analyze the hydrochemical process and assess the groundwater quality and human health risks in a coastal area of southeastern China. The results showed that the concentrations of major ions were in the order of Ca2+> Mg2+ > Na+ > K+ and HCO3- > SO42- > Cl- > NO3- > F- during the pre- and post-monsoon periods. A slight increase was observed during the post-monsoon period. The Piper diagram suggested that the hydrochemical type of groundwater was predominantly HCO3-Ca. Principal component analysis (PCA), ionic ratios, and saturation index (SI) determined that the water-rock interactions involving silicate and carbonate minerals played a significant role in the hydrochemical process. The results of the entropy-weighted water quality index (EWQI) and irrigation water quality index (IWQI) evaluations revealed that the general qualities of groundwater were suitable for both drinking and irrigation purposes. However, the excesses of NO3- and SO42- were observed locally. Human health risk assessment concluded that groundwater posed a low risk to human health, and infants faced higher risk compared with adults. The study would provide valuable information for groundwater environmental protection.

Predicting vulnerability through hybrid modeling combining GAM and XGBoost - A case of affected population vulnerability to tropical cyclone in Hainan Province

Tropical cyclones are one of the most destructive natural disasters, frequently occurring in the southeastern coastal areas of China, causing huge losses. Accurate characterization and prediction of negative impacts are necessary to minimize impact on coastal cities. However, a complex interaction between hazard intensity and other drivers is involved in the impact of some extreme tropical cyclones, which are often worthy of attention. In this study, a quantitative vulnerability assessment model of tropical cyclones considering the mutual relation between hazard intensity and environmental drivers was developed using the generalized additive model (GAM), random forest (RF), and extreme gradient boosting (XGBoost) for the case of Hainan Province, China. In the testing dataset, the root mean squared error of the optimal model was 0.1393, and the mean absolute percentage error of the optimal model was 35.2 % for spikes in the affected population rate. The spikes in the affected population rate were predicted well by the hybrid model jointly considering nonlinear multivariable regression models and undersampling machine learning methods.

Predicting potential habitat distribution of the invasive species Rhynchophorus ferrugineus Olivier in China based on MaxEnt modelling technique and future climate change.

Changes in the distribution of species due to global climate change have a critically significant impact on the increase in the spread of invasive species. An in-depth study of the distribution patterns of invasive species and the factors influencing them can help to better predict and combat invasive alien species. Rhynchophorus ferrugineus Olivier is an invasive species that primarily harms plants of Trachycarpus H. Wendl. The pest invades trees in three main ways: by laying eggs and incubating them in the crown of the plant, on roots at the surface and at the base of the trunk or petiole. Most of the plants in the genus Trachycarpus are taller, and the damage is concentrated in the middle and upper parts of the plant, making control more difficult. In this paper, we combine 19 bioclimatic variables based on the MaxEnt model to project the current and future distributions of R. ferrugineus under three typical emission scenarios (2.6 W m-2 (SSP1-2.6), 4.5 W m-2 (SSP2-4.5) and 8.5 W m-2 (SSP5-8.5)) in the 2050s and 2090s. Among the 19 bioclimatic variables, five variables were screened out by contribution rates, namely annual mean temperature (BIO 1), precipitation of driest quarter (BIO 17), minimum temperature of coldest month (BIO 6), mean diurnal range (BIO 2) and precipitation of wettest quarter (BIO 16). These five variables are key environmental variables that influence habitat suitability for R. ferrugineus and are representative in reflecting its potential habitat. The results showed that R. ferrugineus is now widely distributed in the southeastern coastal area of China (high suitability zone), concentrating in the provinces of Hainan, Guangdong, Fujian, Guangxi and Taiwan. In the future, the area of high and low suitability zones will increase and the area of medium suitability zones will decrease. The area of low suitability zone will still be in the largest proportion. This study aims to provide a theoretical reference for the future control of R. ferrugineus from the perspective of geographic distribution.

Modernization and Inheritance of Folk Beliefs in the Digital Age: A Case Study in the Southeastern Coastal Areas of China

With the processes of urbanization and population migration in China, local traditional folk beliefs are facing a crisis of inheritance, including the loss of believers and the decline of religious buildings. However, in the southeastern coastal areas of China, with the development of society and the advancement of science and technology, folk beliefs have shown a trend of modernization, gained widespread attention from young people, and shown a good trend of inheritance. This study focuses on the modernization of folk beliefs in the southeastern coastal areas of China, exploring how folk beliefs are adapted to contemporary life and the key role of information technology in the protection of religious buildings. The study found that the modernization of folk beliefs in China’s southeastern coastal areas is mainly reflected in the portrayal of gods in cartoonish images, the popularity of music, and the modernization of communication methods. By analyzing the modernization process of folk beliefs in the southeastern coastal areas of China, this study reveals the adaptation and development of folk beliefs in modern society. Based on the reality of contemporary Chinese society, this study also explores the future modernization trend of folk beliefs and discusses the possibilities and potential risks of the application of digital technology in folk belief inheritance.

Probabilistic fragility assessment of slopes considering uncertainty associated with temporal patterns of rainfall intensity

The temporal patterns of rainfall intensity, characterized by the variability of rainfall intensity over time during a single rainfall event, play a crucial role in landslide triggering and evolution. However, the influence of temporal patterns of rainfall intensity on the fragility and reliability assessment of slope instability has received limited attention. This study presents a novel methodology for probabilistic slope fragility assessment accounting for uncertainty associated with the temporal patterns of rainfall intensity. Hourly-scale random time series for the rainfall event are generated, considering uncertainties in temporal patterns of rainfall intensity, using the statistical concepts of skewness and kurtosis within the Pearson system of distributions. A time-dependent seepage-stability mechanical model coupling the finite element method and limit equilibrium method for the slope under hourly-scale rainfall time series is established. Slope fragility assessment under rainfall is conducted, accounting for uncertainties in temporal patterns of rainfall intensity based on Monte Carlo simulation. An illustrative example is provided, focusing on a hypothetical soil slope in the southeastern coastal area of China, susceptible to rainfall-induced landslides. The impact of skewness and kurtosis of rainfall time series on the slope failure probability and failure time are examined.

Analysis of Distribution and Drug Susceptibility Test Results of Pathogenic Bacteria in Diabetic Foot Ulcers.

This study aimed to determine the pathogen distribution and drug susceptibility of diabetic foot wound secretions in a tertiary hospital in a coastal area of southeastern China to guide clinical antibiotic selection. A retrospective analysis was conducted on 212 patients with diabetic foot hospitalized at Xiamen Third Hospital from 2018 to 2023, and foot wound secretions were collected for microbial culture and drug susceptibility testing. Among 212 cases of patients with diabetic foot wound secretions, 163 cases (76.9%) were cultured with pathogenic bacteria, and a total of 207 strains of pathogenic bacteria were cultured, including 75 strains (36.23%) of Gram-positive (G+) bacteria, 118 strains of Gram-negative (G-) bacteria (57.00%), 14 strains of fungi (6.76%), 120 cases of single microorganism infection (73.62%), 43 cases of mixed infection (26.38%), and 15 strains of multidrug-resistant bacteria (7.25%). The top three pathogenic bacteria were Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa. G+ bacteria were dominated by S.aureus. Drug susceptibility results showed that G+ bacteria were highly susceptible to vancomycin, linezolid, tigecycline, quinupristin/dalfopristin, rifampicin, and furotoxin, and somewhat resistant to penicillin, erythromycin, clindamycin, and cefoxitin. Among G- bacterial infections, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, and Proteus were the major species. Drug susceptibility testing indicated that carbapenems such as imipenem and ertapenem were the most effective antibacterial drugs against G- strains, followed by amikacin, piperacillin, and tazabactams to which these bacteria were also relatively sensitive, while resistance to penicillins and first-generation cephalosporins increased significantly. We isolated one strain of pathogenic bacteria from a Wagner grade1 ulcer, which was G+ bacteria. In Wagner grade2 ulcers, the distribution of pathogenic bacteria was mainly G+ bacteria. In Wagner grade3 and 4 ulcers, the distribution of pathogenic bacteria was mainly G- bacteria, and the increased rate of mixed infection was mainly due to mixed infection of G+ and G-. Two strains of pathogenic bacteria were isolated at Wagner grade5, which were mixed infections of G+ and G-. Pathogenic bacteria in diabetic foot wounds are predominantly G- bacteria, followed by G+ bacteria. As the Wagner ulcer grade increases, the distribution of pathogenic bacteria changes from G+ bacteria to G- bacteria, and the mixed infection rate increases. G+ bacteria are highly susceptible to vancomycin, linezolid, tigecycline, quinupristin/dalfopristin, rifampicin, and furotoxin, and somewhat resistant to penicillin, erythromycin, clindamycin, and cefoxitin. G- bacteria are more sensitive to the antimicrobial drugs ertapenem, imipenem, amikacin, piperacillin tazobactam, and have high resistance to penicillin and first-generation cephalosporins.

Estimation of scrub typhus incidence and spatiotemporal multicomponent characteristics from 2016 to 2023 in Zhejiang Province, China.

China is one of the main epidemic areas of scrub typhus, and Zhejiang Province, which is located in the coastal area of southeastern China, is considered a key region of scrub typhus. However, there may be significant bias in the number of reported cases of scrub typhus, to the extent that its epidemiological patterns are not clearly understood. The purpose of this study was to estimate the possible incidence of scrub typhus and to identify the main driving components affecting the occurrence of scrub typhus at the county level. Data on patients with scrub typhus diagnosed at medical institutions between January 2016 and December 2023 were collected from the China Disease Control and Prevention Information System (CDCPIS). The kriging interpolation method was used to estimate the possible incidence of scrub typhus. Additionally, a multivariate time series model was applied to identify the main driving components affecting the occurrence of scrub typhus in different regions. From January 2016 to September 2023, 2,678 cases of scrub typhus were reported in Zhejiang Province, including 1 case of reported death, with an overall case fatality rate of 0.04%. The seasonal characteristics of scrub typhus in Zhejiang Province followed an annual single peak model, and the months of peak onset in different cities were different. The estimated area with case occurrence was relatively wider. There were 41 counties in Zhejiang Province with an annual reported case count of less than 1, while from the estimated annual incidence, the number of counties with less than 1 case decreased to 21. The average annual number of cases in most regions fluctuated between 0 and 15. The numbers of cases in the central urban area of Hangzhou city, Jiaxin city and Huzhou city did not exceed 5. The estimated random effect variance parameters , , and were 0.48, 1.03 and 3.48, respectively. The endemic component values of the top 10 counties were Shuichang, Cangnan, Chun'an, Xinchang, Pingyang, Xianju, Longquan, Dongyang, Yueqing and Qingyuan. The spatiotemporal component values of the top 10 counties were Pujiang, Anji, Pan'an, Dongyang, Jinyun, Ninghai, Yongjia, Xiaoshan, Yinwu and Shengzhou. The autoregressive component values of the top 10 counties were Lin'an, Cangnan, Chun'an, Yiwu, Pujiang, Longquan, Xinchang, Luqiao, Sanmen and Fuyang. The estimated incidence was higher than the current reported number of cases, and the possible impact area of the epidemic was also wider than the areas with reported cases. The main driving factors of the scrub typhus epidemic in Zhejiang included endemic components such as natural factors, but there was significant heterogeneity in the composition of driving factors in different regions. Some regions were driven by spatiotemporal spread across regions, and the time autoregressive effect in individual regions could not be ignored. These results that monitoring of cases, vectors, and pathogens of scrub typhus should be strengthened. Furthermore, each region should take targeted prevention and control measures based on the main driving factors of the local epidemic to improve the accuracy of prevention and control.

Palynological and sedimentological evidence for early mid-Holocene hydroclimatic variability in the Ningshao Plain, East China

The southeastern coastal areas of China represent one of the most populous and economically developed regions in China, but they are often severely affected by flood hazards. Therefore, studying the phenomenon and mechanisms behind extreme rainfall changes in this region is of great significance for economic and social development. In this study, we present high-resolution pollen and grain-size records from the Shanglin Lake located in Zhejiang, eastern China, based which changes in the frequency of paleo-flood events were reconstructed and the climatic context was inferred. Our pollen records show that the content of evergreen broadleaf trees gradually increased during 8000–7000 cal. yr BP, reflecting the gradually increasing temperature in the growing season. The content of Altingia increased substantially during the periods of 7960–7860, 7600–7500, and 7200–7100 cal. yr BP, especially in the first and last periods, indicating the prevalence of an El Niño-like condition in the study area during the early mid-Holocene warm period. Grain-size record shows that the prolonged El Niño condition facilitated a significant increase in flood frequency. Our results suggest that, similar to that of today, the early mid-Holocene warm climate was the most important factor controlling extreme hydroclimatic changes in the middle and lower reaches of the Yangtze River.

Development of composite drought indices for the coastal areas of southeastern China: A case study of Jinjiang and Jiulongjiang River basins

Given the complexity of coastal drought events and their unique impacts on coastal ecosystems, it is vital to develop drought indices that can reflect both freshwater availability and impacts on ecological resources to better assess drought conditions over coastal regions. Existing drought indices developed for upland areas may not be suitable to capture the timing and severity of drought in the coastal regions. To explore coastal drought issue more comprehensively, this paper constructed the Coastal Composite Drought Indices (CCDIs) based on the entropy-weighted Euclidean distance method by freely combining six variables: precipitation (P), evaporation (E), runoff (R), salinity (S), Normalized Difference Vegetation Index (NDVI) and Land Surface Temperature (LST), in the Jinjiang River Basin (JJRB) and the Jiulong River Basin (JLRB). The CCDIs were later compared to the Standardized Precipitation Index (SPI) and Palmer Drought Severity Index (PDSI) to select the Optimized Drought Indices (ODIs). The results demonstrated that the Precipitation Evaporation Runoff Composite Index (PER) is more sensitive to capturing short-term coastal drought events compared to other CCDIs. PER performed better than SPI and PDSI in detecting the onset of drought development and reflecting drought persistence. The salinity exhibited mixed responses to long-term drought events in different river basins depending on the size of each coastal system and its characteristics, thus raising the issue of regional applicability. Through a series of cross-comparisons and validations, the Runoff NDVI LST Composite Index (RNL) and the Runoff Salinity NDVI Composite Index (RSN) were chosen to monitor long-term droughts in the JJRB and JLRB, respectively. Overall, all three indices have the ability to capture the dynamics and trends of the variables and provide better information on the occurrence, persistence, and end of droughts in coastal areas.

Paleozoic VMS-type stratiform mineralization overprinted by Mesozoic vein-type mineralization in the Yushui copper deposit, eastern Guangdong, South China

The South China hosts a number of stratiform deposit in Late Paleozoic depression, including the Yushui copper deposit (which has a Cu grade up to 53% with an average grade of about 3.5%) in the Yong-Mei-Hui depression. The genesis type of Yushui copper ore is highly controversial due to the influence of post mineralization tectonic and magmatic activities, which affects the exploration of the deposits. Yushui copper deposit is mainly composed of stratiform ore body and stockwork orebody in the footwall, with typical VMS-type deposit characteristics and its mineralization age of 308 Ma. Small amounts of vein-type ore body can also be seen in the hanging wall dolomite of the stratiform ore body, which mainly develops along the joints and faults, and the mineral assemblage includes chalcopyrite, bornite, galena, sphalerite, tetrahedrite, furutobeite, and rare earth minerals (xenotime and bastnaesite). Hydrothermal sericite is also developed when vein-type ore body cut the sandstone in the footwall of stratiform ore body. Pristine euhedral xenotime and bastnaesite crystals from the Yushui Cu mineralized of veins ore body yield LA-ICP-MS weighted mean 206Pb/238U ages of 162.5 ± 6.7 Ma (1 s, MSWD = 11.8) and 164.6 ± 5.3 Ma (1 s, MSWD = 9.5), respectively. Hydrothermal sericite yields a plateau 40Ar–39Ar age of 163.19 ± 7.60 Ma, which is consistent with the xenotime and bastnaesite U–Pb age, suggesting that the vein-type Cu mineralized is generically related to the Middle-Late Jurassic hydrothermal event. These ages indicate that in addition to the major Late Paleozoic mineralization events that formed VMS-type stratiform ore body, there were also small-scale hydrothermal vein-type ore body formed during the Middle and Late Jurassic mineralization events that did not cause major disruptions to the earlier stratiform ore body. Combining with the chronological research of other copper deposits in the southeastern coastal area of China, this article believes that these 170 ∼ 155 Ma deposits were all due to the crust-mantle interaction caused by changes in the subduction angle of the ancient Pacific plate. Our study suggests that the southeastern margin of the South China has potential for the exploration of polymetallic hydrothermal mineralization related to Middle-Late Jurassic magmatic rock.

Multi-Objective Optimization of Envelope Design of Rural Tourism Buildings in Southeastern Coastal Areas of China Based on NSGA-II Algorithm and Entropy-Based TOPSIS Method

The rapid development of rural tourism and higher requirements for the indoor environments of rural tourism buildings (RTBs) have led to rapid growth in the energy consumption of RTBs. The aim of this work was to apply a new method to optimize the indoor thermal environments and energy performances of RTBs and promote scientific passive design strategies for RTBs in southeastern coastal areas of China. First, a field survey was carried out to understand the statuses of buildings and the energy consumption of RTBs. Through a building typology analysis, two types of RTBs (renovated from existing buildings and newly built) were chosen as the dominant types in the villages. Second, a comprehensive parametric study was conducted to examine the impact of energy consumption and the indoor thermal environment using a global sensitivity analysis. The passive design parameters with large sensitivity impacts were selected using the Sobol sampling method and by calculating the comprehensive contribution rates of the parameters. Then, the NSGA-II algorithm was used to simultaneously minimize the two objectives and generate the Pareto front solution sets of the two RTB types. Finally, by applying an entropy-based TOPSIS decision-making method, the optimal schemes (the best energy-saving solution, the best comfort solution, and the best compromise solution) for the two RTB types were further obtained from the feasible Pareto-optimal solutions, and the suggested values for the design parameters are presented. This study proposes a new multi-objective optimization approach combining the NSGA-II algorithm and an entropy-based TOPSIS decision-making method, and the findings are valuable, as they can help designers to improve the designs of rural tourism buildings.

An Early Cretaceous magmatic-hydrothermal origin of the Shanhou stratabound Pb-Zn deposit in Fujian Province of southeast China: Constraints from hydrothermal titanite U-Pb dating and C-O-S-Pb isotopes

Stratabound base metal sulfide deposits within Neoproterozoic metavolcanic rocks and skarns in the Fujian Province are important Zn-Pb producers in China. To date, the inability to determine absolute ages and proper sources of Pb-Zn mineralization has led to conflicting ore genetic models. These include the metamorphosed volcanogenic massive sulfide (VMS) model, which predicts that the Pb-Zn mineralization was synchronous with submarine volcanic activity, and the Early Cretaceous magmatic-hydrothermal skarn model. The Shanhou deposit (2.56 Mt ore @ 6.8 % Pb + Zn) in the central Fujian Province, the southeastern coastal area of China, consists of twelve stratabound massive Pb-Zn sulfide orebodies hosted in hydrothermally altered metavolcanic rocks of the Neoproterozoic Dongyan Formation. No intrusive body that could have contributed to the formation of the calc-silicate mineral-dominated wall rocks and Pb-Zn ores has been found spatially associated with the Shanhou deposit, and the origin of the mineralizing fluids, sulfur, and metals has not yet been identified previously. Here we present in-situ U-Pb ages of hydrothermal titanite and C-O-S-Pb isotopes of gangue and ore minerals to constrain the timing and origin of the Pb-Zn mineralization. Three hydrothermal stages can be identified: pyroxene (prograde stage I), epidote + chlorite + titanite (retrograde stage II), and quartz + calcite + polymetallic sulfides (quartz-calcite-sulfide stage III). In-situ LA-ICP-MS U-Pb isotopic analyses of hydrothermal titanites coexisting with sulfides in two massive ore samples yield indistinguishable ages of 145 ± 13 Ma and 144 ± 9 Ma, overlapping the 152 to 145 Ma emplacement age of granitic rocks in the central Fujian area. The results show that the Shanhou Pb-Zn deposit is significantly younger than the Neoproterozoic host (meta)volcanic rocks, arguing against a Neoproterozoic VMS genetic model as suggested by some previous researchers. The δ34S (V-CDT) values of pyrrhotite, pyrite, marcasite, chalcopyrite, sphalerite, and galena in the massive sulfide ores range from −2.9 to 6.9 ‰, indicating that the sulfur at Shanhou is mainly of magmatic origin. Sphalerite separates have 206Pb/204Pb ratios of 17.782 to 17.782, 207Pb/204Pb ratios of 15.585 to 15.593, and 208Pb/204Pb ratios of 38.376 to 38.407, which are similar to those of the host rocks, indicating that the ore-forming materials were derived from the host rocks. Calcite in sulfide ores has δ13CV-PDB values of −7.8 to −4.3 ‰ and δ18OV-SMOW values of 6.1 to 9.5 ‰, suggesting a magmatic origin for the ore-forming fluids. It is concluded that the Shanhou stratabound Pb-Zn deposit is a metasomatic skarn-like deposit associated with a possible hidden Early Cretaceous felsic intrusion at depth, rather than a metamorphosed VMS deposit.

Undrained deformation behavior of marine clay under two-way cyclic loading

In offshore engineering, marine clays, which are widespread in the southeastern coastal areas of China, may be subjected to two-way cyclic stresses. To experimentally investigate the effects of the two-way cyclic stress with low-stress amplitude on the cyclic behavior of soft marine clay, a series of triaxial tests is performed on intact marine clay from Zhoushan covering various values of the cyclic stress ratio (CSR) and confining pressure (p′0). Several useful conclusions are inferred: First, the double-amplitude axial strain (ε DA), dynamic axial modulus (E), and energy dissipation (W) increase with the CSR. Second, under the same CSR, the value of ε DA is independent of p′0. The values of E and W increase with increasing p′0 during cyclic loadings, whereas the normalized modulus and normalized energy are independent of p′0. Third, an allowable CSR is proposed based on the strain behavior and energy concept. Based on the experimental results, two equations are established to predict the dynamic axial modulus and double-amplitude axial strain.

Copula-Based Assessment and Regionalization of Drought Risk in China.

Droughts are widespread in China and have brought considerable losses to the economy and society. Droughts are intricate, stochastic processes with multi-attributes (e.g., duration, severity, intensity, and return period). However, most drought assessments tend to focus on univariate drought characteristics, which are inadequate to describe the intrinsic characteristics of droughts due to the existence of correlations between drought attributes. In this study, we employed the standardized precipitation index to identify drought events using China's monthly gridded precipitation dataset from 1961 to 2020. Univariate and copula-based bivariate methods were then used to examine drought duration and severity on 3-, 6-, and 12-month time scales. Finally, we used the hierarchical cluster method to identify drought-prone regions in mainland China at various return periods. Results revealed that time scale played an essential role in the spatial heterogeneity of drought behaviors, such as average characteristics, joint probability, and risk regionalization. The main findings were as follows: (1) 3- and 6-month time scales yielded comparable regional drought features, but not 12-month time scales; (2) higher drought severity was associated with longer drought duration; (3) drought risk was higher in the northern Xinjiang, western Qinghai, southern Tibet, southwest China, and the middle and lower reaches of the Yangtze River, and lower in the southeastern coastal areas of China, the Changbai Mountains, and the Greater Khingan Mountains; (4) mainland China was divided into six subregions according to joint probabilities of drought duration and severity. Our study is expected to contribute to better drought risk assessment in mainland China.

Zircon reveals crystal-melt segregation processes in the genesis of Cretaceous A-type granites and related cumulated rocks in southeastern China

A-type granites are a distinctive group of igneous rocks classified based on chemical and mineralogical criteria. Although numerous theories for the origin of A-type granite have previously been proposed, their genesis remains highly controversial. In the current study, we present bulk-rock geochemistry and zircon UPb isotopes, Hf isotopes, and trace elemental data for a suite of quartz monzonite, porphyritic granite, and miarolitic alkali feldspar granite from the coastal area of Fujian, southeastern China, to evaluate the genetic link between these rocks. Zircon UPb dating indicates that these rocks were crystallized at ∼94–102 Ma. Our data strongly suggests that lithological differences in these rocks are the result of crystal-melt segregation in the shallow crust. The quartz monzonites are enriched in Sr and Ba, with high Zr/Hf and low silica content and a weak negative Eu anomaly, representing the cumulate residue from the crystal-melt segregation of a magma reservoir. A limited fraction of zircon from the quartz monzonite has evolved trace element signatures (high Hf, Nb, Y, U; low Eu/Eu⁎), indicating that the quartz monzonite represents a mixture of accumulated crystals and high silicic melt trapped in cumulate mush. The miarolitic alkali feldspar granites and porphyritic granites are enriched in silica and Rb, and depleted in Sr and Eu. They also display low whole-rock Zr/Hf and Eu/Eu⁎ ratios, and high Rb/Sr ratios, representing highly evolved silicic melts that were segregated from a magma reservoir. The majority of the zircon grains from the miarolitic alkali feldspar granites exhibit the most evolved trace element signatures (high Hf, Nb, Y, U; low Zr/Hf and Eu/Eu⁎) of the entire suite. This reveals that these zircons crystallized from the high silicic melts extracted from a magma reservoir. Magma recharge and the exsolution of volatiles from the interstitial melt have promoted the segregation and upward extraction of high silica magmas from a compacting magma reservoir in the upper crust. Our work demonstrates that the miarolitic alkali feldspar granites with A-type granite features from the coastal area of southeastern China were generated by the crystal-melt segregation process in a shallow crustal magma reservoir.

Examining the functionality of digital platform capability in driving B2B firm performance: evidence from emerging market

PurposeThis study aims to explore the influence mechanism of digital platform capability on firm performance in the business-to-business (B2B) context. This study draws on the core competence theory and the resource-based view and includes resource identification, resource allocation and intrapreneurship into the research framework.Design/methodology/approachData were collected from 167 B2B firms with survey questionnaires in central, eastern and southeastern coastal areas of China. The firms were mainly involved in e-commerce, manufacturing, service industry and internet technology. Participants were mainly middle and senior managers with a comprehensive grasp of their firms’ information.FindingsThis study found that digital platform capability has a positive impact on a B2B firm’s performance. Resource identification, resource allocation and intrapreneurship play a chain mediating role between digital platform capability and firm performance. That is, digital platform capability could promote employee intrapreneurship through resource identification and resource allocation, thereby improving firm performance.Practical implicationsAiming to gain performance, firms should pay attention to the construction of digital platforms, increase venture capital investment and provide more resources to support intrapreneurship.Originality/valueBased on empirical evidence, to the best of authors’ knowledge, this is the first attempt to link digital platform capability and firm performance in the B2B context of emerging markets, providing a new perspective to clarify its relationship mechanism.

A Study on a Neural Network Risk Simulation Model Construction for Avian Influenza A (H7N9) Outbreaks in Humans in China during 2013-2017.

The main purposes of this study were to explore the spatial distribution characteristics of H7N9 human infections during 2013–2017, and to construct a neural network risk simulation model of H7N9 outbreaks in China and evaluate their effects. First, ArcGIS 10.6 was used for spatial autocorrelation analysis, and cluster patterns ofH7N9 outbreaks were analyzed in China during 2013–2017 to detect outbreaks’ hotspots. During the study period, the incidence of H7N9 outbreaks in China was high in the eastern and southeastern coastal areas of China, with a tendency to spread to the central region. Moran’s I values of global spatial autocorrelation of H7N9 outbreaks in China from 2013 to 2017 were 0.080128, 0.073792, 0.138015, 0.139221 and 0.050739, respectively (p < 0.05) indicating a statistically significant positive correlation of the epidemic. Then, SPSS 20.0 was used to analyze the correlation between H7N9 outbreaks in China and population, livestock production, the distance between the case and rivers, poultry farming, poultry market, vegetation index, etc. Statistically significant influencing factors screened out by correlation analysis were population of the city, average vegetation of the city, and the distance between the case and rivers (p < 0.05), which were included in the neural network risk simulation model of H7N9 outbreaks in China. The simulation accuracy of the neural network risk simulation model of H7N9 outbreaks in China from 2013 to 2017 were 85.71%, 91.25%, 91.54%, 90.49% and 92.74%, and the AUC were 0.903, 0.976, 0.967, 0.963 and 0.970, respectively, showing a good simulation effect of H7N9 epidemics in China. The innovation of this study lies in the epidemiological study of H7N9 outbreaks by using a variety of technical means, and the construction of a neural network risk simulation model of H7N9 outbreaks in China. This study could provide valuable references for the prevention and control of H7N9 outbreaks in China.

Assessment of combined wind and wave energy in the tropical cyclone affected region:An application in China seas

Marine renewable energy resources are important for clean energy development. Research on the combined assessment of wind and wave resources, especially in tropical cyclone (TC) affected area is still rare. This study is to assess the potential combined wind and wave energy in the coastal waters of China, where TCs frequently occurred. The study utilizes the blended wind field with a parametric TC model based on the ECMWF reanalysis wind data from 1979 to 2013 for assessing potential wind energy, and the waves generated by the same wind data using the FVCOM-SWAVE model for assessing wave energy. The combined wind and wave energy density and annual power generation are analyzed. The potential energy from wind and waves at 15 nearshore locations along China east coasts are estimated. The results show that the frequency and intensity of TCs have a considerable impact on the distribution of density and stability of wind and wave energy, especially in the southeastern coastal areas of China. Suggestions of site selection of co-located wind and wave farm in the coastal waters of China are given. The research outcome provides a useful guidance for the selection of potential sites and design of wind and wave energy converters along the China coasts.

Characterization, reactivity, source apportionment, and potential source areas of ambient volatile organic compounds in a typical tropical city

Based on one-year observation, the concentration, sources, and potential source areas of volatile organic compounds (VOCs) were comprehensively analyzed to investigate the pollution characteristics of ambient VOCs in Haikou, China. The results showed that the annual average concentration of total VOCs (TVOCs) was 11.4 ppbV, and the composition was dominated by alkanes (8.2 ppbV, 71.4%) and alkenes (1.3 ppbV, 20.5%). The diurnal variation in the concentration of dominant VOC species showed a distinct bimodal distribution with peaks in the morning and evening. The greatest contribution to ozone formation potential (OFP) was made by alkenes (51.6%), followed by alkanes (27.2%). The concentrations of VOCs and nitrogen dioxide (NO2) in spring and summer were low, and it was difficult to generate high ozone (O3) concentrations through photochemical reactions. The significant increase in O3 concentrations in autumn and winter was mainly related to the transmission of pollutants from the northeast. Traffic sources (40.1%), industrial sources (19.4%), combustion sources (18.6%), solvent usage sources (15.5%) and plant sources (6.4%) were identified as major sources of VOCs through the positive matrix factorization (PMF) model. The southeastern coastal areas of China were identified as major potential source areas of VOCs through the potential source contribution function (PSCF) and concentration-weighted trajectory (CWT) models. Overall, the concentration of ambient VOCs in Haikou was strongly influenced by traffic sources and long-distance transport, and the control of VOCs emitted from vehicles should be strengthened to reduce the active species of ambient VOCs in Haikou, thereby reducing the generation of O3.