Southern Regions Of China Research Articles

Nowcasting and Forecasting Seasonal Influenza Epidemics - China, 2022-2023.

Seasonal influenza resurged in China in February 2023, causing a large number of hospitalizations. While influenza epidemics occurred across China during the coronavirus disease 2019 (COVID-19) pandemic, the relaxation of COVID-19 containment measures in December 2022 may have contributed to the spread of acute respiratory infections in winter 2022/2023. Using a mathematical model incorporating influenza activity as measured by influenza-like illness (ILI) data for northern and southern regions of China, we reconstructed the seasonal influenza incidence from October 2015 to September 2019 before the COVID-19 pandemic. Using this trained model, we predicted influenza activities in northern and southern China from March to September 2023. We estimated the effective reproduction number R e as 1.08 [95% confidence interval ( CI): 0.51, 1.65] in northern China and 1.10 (95% CI: 0.55, 1.67) in southern China at the start of the 2022-2023 influenza season. We estimated the infection attack rate of this influenza wave as 18.51% (95% CI: 0.00%, 37.78%) in northern China and 28.30% (95% CI: 14.77%, 41.82%) in southern China. The 2023 spring wave of seasonal influenza in China spread until July 2023 and infected a substantial number of people.

Randomised Controlled Trial of Self-Affirmation Intervention on Students' Academic Performance: Promising Impacts on Students from Migrant Hukou Status.

Drawing from the sociocultural-self model, this study aims to examine the influence of self-affirmation on the academic outcomes of lower-class migrant students, as well as the psychological mechanism underlying this phenomenon. A field experiment was conducted at a comprehensive secondary school in the southern region of China. Our study sample comprised 1534 immigrant students from diverse regions across the country, with an average proportion of 59.6% of students registered with a rural hukou. The hukou system plays a pivotal role in measuring social class in China, thus it was used as a proxy for lower and higher social class, with rural hukou students considered to be lower-class and urban hukou students considered to be higher-class. Prior to the English test, students in the self-affirmed group were engaged in a brief writing exercise that focused on their core values, whereas the control group wrote about a neutral topic. The primary outcome of interest was the effect of self-affirmation on English test scores, whereas the secondary outcome was the students' survey stereotype threat. The results exhibit that self-affirmation more significantly improved the English test performance of lower-class students compared to higher-class students, and this positive effect was mediated by reducing stereotype threat. Our findings unravel the impact of self-affirmation on the academic performance of migrant students from different social classes and signify the mediating role of stereotype threat in this process. The present study extends previous findings to students from immigrant families in the Chinese cultural context, and these findings demonstrate that self-affirmation can constitute a promising intervention for stereotype threat and achievement gaps due to social class differences in immigrant family groups. Considering that this intervention takes only about 15 minutes of time, entails almost zero cost, does no harm, and that it focuses on disadvantaged immigrant students, it may provide valuable insights for educational policies to be implemented in a new type of migrant city such as Shenzhen.

Discovery of entomopathogenic fungi across geographical regions in southern China on pine sawyer beetle Monochamus alternatus and implication for multi-pathogen vectoring potential of this beetle.

Entomopathogen-based biocontrol is crucial for blocking the transmission of vector-borne diseases; however, few cross-latitudinal investigations of entomopathogens have been reported for vectors transmitting woody plant diseases in forest ecosystems. The pine sawyer beetle Monochamus alternatus is an important wood borer and a major vector transmitting pine wilt disease, facilitating invasion of the pinewood nematode Bursaphelenchus xylophilus (PWN) in China. Due to the limited geographical breadth of sampling regions, species diversity of fungal associates (especially entomopathogenic fungi) on M. alternatus adults and their potential ecological functions have been markedly underestimated. In this study, through traditional fungal isolation with morphological and molecular identification, 640 fungal strains (affiliated with 15 genera and 39 species) were isolated from 81 beetle cadavers covered by mycelia or those symptomatically alive across five regional populations of this pest in southern China. Multivariate analyses revealed significant differences in the fungal community composition among geographical populations of M. alternatus, presenting regionalized characteristics, whereas no significant differences were found in fungal composition between beetle genders or among body positions. Four region-representative fungi, namely, Lecanicillium attenuatum (Zhejiang), Aspergillus austwickii (Sichuan), Scopulariopsis alboflavescens (Fujian), and A. ruber (Guangxi), as well as the three fungal species Beauveria bassiana, Penicillium citrinum, and Trichoderma dorotheae, showed significantly stronger entomopathogenic activities than other fungi. Additionally, insect-parasitic entomopathogenic fungi (A. austwickii, B. bassiana, L. attenuatum, and S. alboflavescens) exhibited less to no obvious phytopathogenic activities on the host pine Pinus massoniana, whereas P. citrinum, Purpureocillium lilacinum, and certain species of Fusarium spp.-isolated from M. alternatus body surfaces-exhibited remarkably higher phytopathogenicity. Our results provide a broader view of the entomopathogenic fungal community on the vector beetle M. alternatus, some of which are reported for the first time on Monochamus spp. in China. Moreover, this beetle might be more highly-risk in pine forests than previously considered, as a potential multi-pathogen vector of both PWN and phytopathogenic fungi.

Melaleuca alternifolia (Maiden & Betche) Cheel Residues Affect the Biomass and Soil Quality of Plantation

Long-term unreasonable management has led to the continuous decline of soil quality in Melaleuca alternifolia planting areas in southern China, and there is no effective way to improve its soil quality at present. In this study, residues of tea tree oil extraction were returned to the forest to explore its influence on soil quality. Therefore, four test groups (RT, residues were tiled; RS, residues were stacked; RDT, residues were decomposed and tiled; RDS, residues were decomposed and stacked) and one control group (CK, nothing was changed) were designed. We used one-way ANOVA and Pearson correlation analysis to detect 22 physical, chemical, and biological indicators of soil, and then used minimum data set (MDS) and principal component analysis (PCA) to evaluate soil quality. The results show that compared with the CK, BD and pH in the test groups decreases, while CP, TTP, SOM, AN, NN, AP, AK, CEC, MBC, MBN, MBP, catalase, urease, sucrase, and ACP increase or strengthen in different degrees, and the biomass increases by 5.3%~12.8%. The soil quality indexes (SQI) are RDT (0.616) > RT (0.546) > RDS (0.525) > RS (0.452) > CK (0.291). Significant correlation between SQI and biomass indicates that the indicators have high biological significance for the planting areas of Melaleuca alternifolia in the red soil region in southern China. These results show that residues could improve soil quality, and that the soil quality is different among different test groups. This study provides a new path for the management of Melaleuca alternifolia plantation.

Development and External Validation of an Improved Version of the Diagnostic Model for Opportunistic Screening of Malignant Esophageal Lesions.

We aimed to develop an improved version of the diagnostic model predicting the risk of malignant esophageal lesions in opportunistic screening and validate it in external populations. The development set involved 10,595 outpatients receiving endoscopy from a hospital in Hua County, a high-risk region for esophageal squamous cell carcinoma in northern China. Validation set A enrolled 9453 outpatients receiving endoscopy in a non-high-risk region in southern China. Validation set B involved 17,511 residents in Hua County. The improved diagnostic model consisted of seven predictors including age, gender, family history of esophageal squamous cell carcinoma, smoking, body mass index, dysphagia, and retrosternal pain, with an area under the receiver operating characteristic curve (AUC) of 0.860 (95% confidence interval: 0.835-0.886) in the development set. Ideal discrimination ability was achieved in external validations (AUC validation set A: 0.892, 95% confidence interval: 0.858-0.926; AUC validation set B: 0.799, 95% confidence interval: 0.705-0.894). This improved model also markedly increased the detection rate of malignant esophageal lesions compared with universal screening, demonstrating great potential for use in opportunistic screening of malignant esophageal lesions in heterogeneous populations.

A simplified model for analyzing rainwater retention performance and irrigation management of green roofs with an inclusion of water storage layer

Rainwater retention and water content in green roofs are primarily influenced by structural configurations (i.e., soil layer, vegetation layer, and water storage layer) and climatic factors (i.e., rainfall and evapotranspiration (ET)). Based on the principle of water balance, this study proposes a conceptual model for simulating water flow in green roofs with water storage layers. Three green roof model experiments were conducted from August 1st, 2020 to July 31st, 2021 for calibrating and verifying the conceptual model. The proposed model was solved iteratively using a newly developed program in Visual Basic. The results showed that the conceptual model can capture the dynamic variations in the rainwater retention and water content of green roofs well. The average Nash-Sutcliffe efficiency coefficient is 0.65 and the average error is 6%. The annual rainwater retention capacity (RRC) of green roofs in the perennial rainy climate model was on average 28% higher than that in the seasonal rainy climate model. At the expense of water stress, high ET plants significantly increased the annual RRC of green roofs at a low level. As the water storage layer depth increased from zero to 150 mm, the annual RRC of green roofs increased by 41%, and the water stress decreased by 49%. Compared with an increase in water holding capacity and soil depth, the response of the annual RRC and water stress of green roofs for increasing water storage layer depth is much greater. As per climate of Southern China region, the water storage layer depth of 100 mm is found to obtain optimal rainwater retention and irrigation management in green roof with similar soil thickness (100 mm).

Sellaphora tanghongquii sp. nov. (Bacillariophyta, Sellaphoraceae), a new diatom species from the Southern China

Sellaphora tanghongquii sp. nov. is described from epilithic samples taken from river systems in Southern China. The morphology of the new species is described based on light microscopy (LM) and scanning electron microscopy (SEM), and detailed ecological information is provided. This species has diagnostic features consistent with the genus Sellaphora, including small and linear valves, undulate and filiform raphe, and the presence of internal hymenate occlusions. Compared to morphologically similar species, we found that the new species is the most similar to S. constrictum in valve size and outline, raphe structure, and the external arrangement of the striae. However, S. tanghongquii sp. nov. has the following outstanding features which distinguish from similar species: 1) the valve striae are uniseriate externally and biseriate internally, 2) the shape of areolae are mostly square to elliptical, partly round, oval or irregularly shaped, composed of 2–4 small holes inside externally and round, elliptical, C-shaped, or irregularly shaped internally, 3) undulate valves with a slight constriction near the central portion of the valve, and 4) the presence of a row of separated and small pores on the valve mantle. The species appears to be best assigned to the group of species with axial grooves, which includes the generitype of Sellaphora. The discovery of this new diatom species increases the known biodiversity of the southern regions in China.

First Report of Puccinia engleriana Causing Leaf Rust of Tabernaemontana bufalina in Hainan, China.

Tabernaemontana bufalina Lour. is extensively cultivated as an ornamental plant in Hainan, Guangdong, and other regions of southern China. In January 2020, we observed a rust disease on T. bufalina leaves in Sanya (18.15。N and 109.30。E) Hainan, China, and the rust occurred all year-round. In the early stage of rust, yellow chlorotic spots appeared, and then uredinia on the abaxial leaf surface became visible. Uredinia (approximately 200-700 µm in diameter) were mostly yellowish-brown in color, solitary, and irregularly scattered. In the late stage of the disease, spots were connected into lesions, and eventually, the whole leaf became severely chlorotic. Urediniospores were light brown, subglobose, measured 25-30 µm × 20-25 µm. They had two pores and were echinulate with spines spaced 2-5 µm. The teliospores were naked, scattered, or aggregated on severely infected leaves. They were two-celled, measured 33-40 µm × 25-30 µm, elliptic, dark brown, and covered with tiny spines. The teliospores had a colorless pedicel at one end which was approximately 28-34 µm long and enlarged at the lower part. The morphological characteristics of the spores were consistent with the descriptions of Puccinia engleriana Henn. (Hennings 1905). In China, P. engleriana was first identified on the leaves of Tabernaemontana divaricata (L.) in Yunnan province, and recorded as new to China in 2012 (Zhuang 2012). Untill now, no leaf rust caused by P. engleriana has been reported in Hainan. Urediniospores were collected and DNA was extracted using a Quick-DNA extraction Kit (TIANGEN Biotech, Beijing, China). The nuclear large subunit (28S) region of the ribosomal DNA repeat was amplified with primers Rust28SF (Aime et al. 2018) and LR5 (Vilgalys and Hester 1990) following the protocol of Aime and McTaggart (2021). The length of the large subunit sequence was 1,010 bp. When searched the GenBank database, the sequence showed 97.07% homology to the large subunit ribosomal RNA gene (Sequence ID: MW147048.1) of P. engleriana, and 92.5% similarity with 18S ribosomal RNA gene (Sequence ID: KM249855.1) of P. hemerocallidis. This result was consistent with the morphological identification. As for the 3% difference in large subunit ribosomal RNA gene, it was speculated that it may be related to the differences of geographical distribution and host plants, as the reference P. engleriana was obtained from Tabernaemontana orientalis in Australia (Aime and McTaggart 2021). The large subunit sequence was submitted into the GenBank database, with accession No. MZ314895. T. bufalina cutting seedlings with 4 available leaves were used in the Koch's postulate test. These seedlings were planted in a greenhouse with a 14 h/10 h light/dark photoperiod at 28°C and 65% humidity. The urediniospores suspension (5107/ml in 0.05% Tween 20 solution) was sprayed on 6 healthy seedlings and other 6 seedlings were sprayed with 0.05% Tween 20 solution as a negative control. Two weeks after inoculation, leaf chlorosis and yellowish uredinia were observed on the inoculated seedlings, whereas the non-inoculated seedlings stayed healthy. To our knowledge, this is the first report of P. engleriana causing leaf rust on T. bufalina in Hainan province. This report will provide the reference for future investigation of T. bufalina leaf rust, and for further improvement on the knowledge of the geographical distribution of P. engleriana in China.

Spatiotemporal dynamics of ecological security in a typical conservation region of southern China based on catastrophe theory and GIS.

Ecological security assessment can effectively reflect the ecological status of a region and reveal its level of sustainable development. In this paper, an ecological security-oriented evaluation system was constructed, and the ecological security level of the Dongjiangyuan region from 2000 to 2020 was evaluated based on catastrophe theory and GIS. The results were as follows: (1) As shown in the land use and cover maps, by 2020, the forestland area had decreased the most, and the artificial surface area had increased the most. (2) The ecological security index of the Dongjiangyuan region showed a low trend in the artificial surface area and its surrounding areas. The quite low values of the ecological security index in 2000 and 2010 were improved in 2020 due to the increase in ecological services capacity. The increased vegetation cover from 2000 to 2020 promoted the improved ecological service capacity. (3) The rapid urbanization process in the Dongjiangyuan region resulted in a lower ecological sensitivity index value. Notably, the ecological sensitivity index of the study area had a slightly decreasing trend. (4) The spatial autocorrelation showed that the proportion of hot and cold spots from 2000 to 2020 decreased by 2.96% and 6.91%, respectively. This study can provide a scientific basis and decision-making guidance for ecological management in the Dongjiangyuan region in the future.

Effects of Oyster Shell Powder and Lime on Availability and Forms of Phosphorus and Enzyme Activity in Acidic Paddy Soil

Soil acidification improvement in the main grain production regions of southern China is an important issue to enhance the quality of cultivated land and promote grain yield. In order to explore the effects of oyster shell powder and lime on acidity and availability and inorganic forms of phosphorus in acidic paddy soil, a pot experiment was performed using oyster shell powder and lime amendments with dosages of 0.05%, 0.10%, and 0.15%. The results showed that both oyster shell powder and lime significantly (P<0.05) increased the pH and decreased exchangeable acid content of paddy soil. The improvement effects increased with the dosage of soil amendments. Under the same amendment dosage, the effects of lime on soil pH and acidity were higher than those of oyster shell powder. Both lime and oyster shell powder significantly increased the content of available P extracted using H2SO4-P, Bray-1 P, and Olsen-P techniques. The contents of inorganic P in soils decreased in the order of Fe-P>Al-P>Ca-P. The application of lime and oyster shell powder significantly increased the contents of Al-P and Fe-P in soil. Compared with the control treatment, lime and oyster shell power increased Al-P and Fe-P by 26.3%-37.4% and 7.9%-23.7%, respectively. However, there was no significant difference in Al-P content among treatments of the three amendment dosages. The contents of Fe-P and Ca-P in soils increased with an increased dosage of amendments. The activities of DHA, ALP, and IPP and the copy number of the phoD gene in soil increased with the application of lime and oyster shell powder, whereas the activities of ACP and the copy numbers of phoC and pqqC decreased. The application of lime and oyster shell powder at a rate of 0.10% and 0.15% significantly (P<0.05) increased the yield of rice. The lime and oyster shell powder treatments at the dosage of 0.15% increased rice yield by 34.2% and 46.8%, respectively, whereas the amendment had no significant effect on straw biomass of the rice crop. Correlation analysis showed that soil pH and the ALP activity were significantly positively correlated with inorganic P and available P contents, respectively. These results suggested that lime and oyster shell power could effectively increase the content of available phosphorus by eliminating soil acidity and improving the phosphatase activity, which played a positive role in increasing crop yield.

Spatio-Temporal Pattern and Influence Mechanism of Rural Human Settlements System Resilience: Case from China

The study of rural habitat systems from the perspective of resilience is of great significance in revealing the inner laws of the evolution of the rural human settlements system and promoting sustainable rural development. This study aims to explain the theoretical connotation of the rural human settlements system resilience (RHSSR), construct an evaluation system and zoning rules for rural habitat system resilience, and explore the spatial distribution pattern of rural habitat system resilience in China and the factors influencing the differences in the level of rural resilience using 30 Chinese provinces as examples to provide effective governance solutions for sustainable rural development. The results show that: (1) The RHSSR refers to the sustainability of the RHSS; i.e., the ability of a system to absorb and adapt to internal and external disturbances and shocks by adjusting the structure and scale of its internal elements, discarding the original inapplicable state to the greatest extent possible and creating a new recovery path to another new equilibrium state. (2) The overall downward trend of RHSSR in 30 Chinese provinces between 2000 and 2020 is consistent with the fact that a large number of villages have died out in China in recent years. (3) The RHSSR is higher in eastern China than in central and western China; although the regional gap is gradually narrowing. (4) An analysis of the evolutionary trend of the RHSSR shows that the northeastern and eastern regions of China belong to the major evolution area of the RHSSR; most areas in central and western China belong to the degraded vulnerable area of the RHSSR, while the potential recession area of the RHSSR is more scattered, mainly in Beijing, Tianjin, and Inner Mongolia in northern China, Chongqing, Hubei, and Qinghai in central China, and Guangdong and Fujian in the southern China region of Guangdong and Fujian. (5) The results of the analysis of geographical detectors show that the effect of the basic-driven factors in the RHSSR decreases significantly with time, while the effect of the core-driven and externally-driven factors increases, and the effect of the two factors is greater than that of the single factor. Among them, industrial structure (IS) has an important influence on the spatial differentiation of the resilience level of rural human settlements system. (6) Optimization strategies are proposed in terms of spatial planning; industrial integration and public participation for the development of different sub-regions.

OSCA Genes in Liriodendron chinense: Characterization, Evolution and Response to Abiotic Stress

The hyperosmolality-gated calcium-permeable channels (OSCA) play an imperative role in the plant response to environmental stresses. Moreover, their characteristics in the ornamental woody plant Liriodendron chinense, widely dispersed in the southern region of China, is yet to be elucidated. In the present study, 399 OSCA proteins were identified from 31 plant genomes, and comparative phylogenetic analysis revealed that LchiOSCAs gene family is closely related to the Magnolia Cinnamomum kanehirae OSCAs. In L. chinense, 11 LchiOSCA genes were identified and distributed across eight chromosomes. Additionally, phylogenetic analysis of LchiOSCAs exhibited a classification into four subfamilies based on the tree arrangement, similarity in the gene structures, and conserved motif numbers and order. Gene duplication investigations were biased towards the tandem duplication events, accounting for 36% (4/11) of the LchiOSCA gene family. The interspecies collinearity analysis revealed a closer relationship between the L. chinense OSCAs and the P. trichocarpa OSCAs. Analysis in promoter regions of the LchiOSCAs showed the presence of multiple phytohormones and stress responsive elements. Specifically, the ABA-responsive elements had the greatest representation. 3D protein structures of the modeled L. chinense OSCAs exhibited a high homology with the template structures, providing a better understanding of LchiOSCAs’ functionality at the proteome level. The expression pattern analysis of LchiOSCAs based on the transcriptome data and qRT-PCR in L. chinense leaves showed differential responses to drought, cold, and heat stress at varying degrees. Specifically, LchiOSCA2 and LchiOSCA4 were highly expressed under the three abiotic stresses. This research will provide valuable resources and further the understanding of plant OSCA genes in L. chinense for agronomic breeding and bio-engineering purposes.

First Report of Trichothecium roseum Causing Postharvest Fruit Rot on Purple Passion Fruit in China.

Purple Passion fruit (Passiflora edulis) is widely cultivated in many regions of southern China as an edible tropical fruit with excellent nutritional value and high economic value. In July 2021, postharvest fruit rot was observed on 20-25% of purple passion fruit in several fruit markets of Dehong City in Yunnan Province. Symptoms on infected fruits were irregular, pink-brown, soft, and water-soaked lesions, which enlarged and formed sunken patches with time as well as producing a small amount of white mycelium. To isolate the causal organism, five diseased fruits were collected from different fruit markets. A conidial mass from an individual sorus observed on an infected fruit was isolated and cultured on potato dextrose agar (PDA) supplemented with 50 μg ml-1 of streptomycin, and five fungal isolates were obtained. These isolates were morphologically similar and produced pale pink colonies on PDA for 7 days containing several conidiophores with abundant conidia. Mycelia were hyaline, 2 µm in diameter, and conidiophores were simple or branched (100 to 286 × 1.5 to 2.5 µm, n=50). Conidia were pyriform, ovate, with papillary protuberances at one end. Almost all conidia were two-celled and single-septate (5.8 to 9.1 × 1.7 to 4.9 µm, n=50). The morphology of the fungi resembled Trichothecium roseum as reported previously (Inácio et al. 2011). To further confirm the fungal species, isolate PASF4 was selected for molecular identification by amplifying and sequencing the ribosomal internal transcribed spacer (ITS) and large subunit (LSU) genes. Primers and PCR amplification were described by Fell et al. (2000). Results showed that both the ITS (GenBank accession OL336243) and LSU (OL336242) gene sequences had 100% similarity to T. roseum in NCBI database (MH856757 and MH868278). Maximum likelihood tree was constructed using MEGA 7 (Felsenstein, 1981) based on concatenated sequences (ITS and LSU) of isolate PASF4 and reference strains. Phylogenetic analysis showed that isolate PASF4 belonged to T. roseum clade. Based on morphological characteristics and phylogenetic analysis, isolate PASF4 was identified as T. roseum (Inácio et al. 2011). To confirm their pathogenicity, healthy purple passion fruits (cv. Tainong-1) were disinfected in 0.5% NaClO solution for 2 min, and then washed with sterile water. After wounding with a sterile needle, the fruits were inoculated by placing mycelium agar plugs on the wounds, and mock inoculation with mycelium-free PDA plugs served as control. Five fruits were used in each treatment. All fruits were maintained in plastic boxes at 25 °C. Disease symptoms appeared after inoculation for 4-7 days on all inoculated fruits, which were similar to those observed in fruit markets. No symptoms were observed on fruits used as control. The Trichothecium isolates were re-isolated from symptomatic fruits thus fulfilling Koch's postulates. Trichothecium roseum has been reported to cause fruit rot of tomato, apple and orange in Pakistan (Hamid et al., 2014) and fruit rot of pepper in China (Lin et al., 2016). To our knowledge, this is the first report of T. roseum causing fruit rot on purple passion fruit worldwide, and these data will provide useful information for developing effective control strategies.

Northern dimming and southern brightening in eastern China during the first decade of the 21st century

Global solar radiation (GSR) reaching the Earth’s surface can directly alter the energy balance of the climate system. The potential influence of inhomogeneity issues on Chinese GSR records on dimming and brightening in China has been argued for years. In this study, we explored the temporal evolution and spatial distribution of the long-term trend of GSR in eastern China (EC) during 1961–2018 using a homogenized GSR dataset, which removed the artificial signals. Results demonstrate that EC experienced a significant dimming period from 1961 to 1999, a brightening period from 2010 until 2018 and a leveling-off period between them (2000–2010), which resulted from opposite trends of GSR in the northern (dimming) and southern (brightening) regions of EC. The reduction of cloud coverage after the dimming period (2000) induced an early coming brightening in the southern region of China between 2000 and 2010, while the increase in aerosols and the rapidly extending cloud fraction resulted in the continuing dimming in northern China.

Fruit Morphology and Fatty Acid Composition of Swida wilsoniana Populations Collected from Different Regions in Southern China

We examined the fruit morphology, oil content, and fatty acids (FAs) of 11 populations of Swida wilsoniana in four provinces in southern China. The fruit oil was extracted by the Soxhlet method, and the FA composition was determined by gas chromatography (GC). The variation in oil content ranged from 16.10 ± 4.94% to 33.08 ± 5.52%, and the major FAs were linoleic acid (44.85 ± 6.70%), oleic acid (29.45 ± 7.63%), palmitic acid (19.59 ± 3.98%), stearic acid (1.95 ± 0.39%), and linolenic acid (0.21 ± 0.07%). The unsaturated FAs accounted for 78.38 ± 3.74%. There was high genetic variation in the oil content and FA composition among the populations. We assessed the relationships between the ecological factors and the FA composition among the populations. The oil content was positively correlated with temperature (r = 0.645, p &lt; 0.05) and negatively correlated with latitude (r = −0.653, p &lt; 0.05). Interestingly, both latitude and temperature were strongly correlated with the unsaturated FAs of the fruits. Principal component analysis (PCA) showed that the populations in different areas could be separated based on oil quality and plant growth. In conclusion, the oil content and FA composition were influenced by geographical area. The findings could help to improve fruit oil quality in future S. wilsoniana breeding programs.

Phylogeographic structure of Heteroplexis (Asteraceae), an endangered endemic genus in the limestone karst regions of southern China.

Though the karst regions in south and southwest China are plant diversity hotspots, our understanding of the phylogeography and evolutionary history of the plants there remains limited. The genus Heteroplexis (Asteraceae) is one of the typical representative plants isolated by karst habitat islands, and is also an endangered and endemic plant to China. In this study, species-level phylogeographic analysis of the genus Heteroplexis was conducted using restriction site-associated DNA sequencing (RADseq). The genetic structure showed a clear phylogeographic structure consistent with the current species boundaries in the H. microcephala, H. incana, H. vernonioides, H. sericophylla, and H. impressinervia. The significant global (R = 0.37, P < 0.01) and regional (R = 0.650.95, P < 0.05) isolation by distance (IBD) signals among species indicate strong geographic isolation in the karst mountains, which may result in chronically restricted gene flow and increased genetic drift and differentiation. Furthermore, the phylogeographic structure of Heteroplexis suggested a southward migration since the last glacial period. Demographic analysis revealed the karst mountains as a refuge for Heteroplexis species. Finally, both Treemix and ABBA-BABA statistic detected significant historical gene flow between species. Significant historical gene flow and long-term stability of effective population size (Ne) together explain the high genome-wide genetic diversity among species (π = 0.05370.0838). However, the recent collapse of Ne, widespread inbreeding within populations, and restricted contemporary gene flow suggest that Heteroplexis species are probably facing a high risk of genetic diversity loss. Our results help to understand the evolutionary history of karst plants and guide conservation.

Comparisons of care practices for very preterm infants and their short-term outcomes in two tertiary centers in northwest and south China: A retrospective cohort study

BackgroundCare practices for very preterm infants and the mortality and morbidity of the infants vary widely among countries and regions with different levels of economic development, including the different areas in China. We aimed to compare the obstetric and delivery room practices of two representative tertiary newborn centers in the northwestern and southern regions of China and the mortality and morbidity of their very preterm infants.MethodsA retrospective cohort study was conducted. Very preterm infants born between 220/7 and 316/7 weeks of gestation, and admitted to Qinghai Red Cross Hospital (QHH) and Shenzhen Baoan Women’s and Children’s Hospital (SZH) from January 1, 2018 to December 31, 2020, were included. The infants’ characteristics and short-term outcomes, and the hospitals’ care practices were compared between the two cohorts.ResultsThree hundred and two infants in QHH and 505 infants in SZH were enrolled, and the QHH cohort was more mature than the SZH cohort was (gestational age 30.14 (29.14–31.14) vs. 29.86 (27.86–31.00 weeks, respectively), p < 0.001). Fewer antenatal steroids and more tracheal intubations were used in QHH than in SZH [(73.8% vs. 90.9%, p < 0.001) and (68.2% vs. 35.0%, p < 0.001, respectively)]. The odds of mortality [aOR = 10.31, 95%CI: (6.04, 17.61)], mortality or major morbidity [aOR = 5.95, 95%CI: (4.05, 8.74)], mortality despite active treatment [aOR = 3.14, 95%CI: (1.31, 7.53)], mortality or major morbidity despite active treatment [aOR = 3.35, 95%CI: (2.17, 5.17)], moderate or severe bronchopulmonary dysplasia [aOR = 3.66, 95%CI: (2.20, 6.06)], and severe retinopathy of prematurity [aOR = 3.24, 95%CI: (1.19, 8.83)] were higher in the QHH cohort. No significant difference in the rate of severe neurological injury or necrotizing enterocolitis ≥ Stage 2 was found between the cohorts.ConclusionObstetric and delivery room care practices used in the management of very preterm infants differed considerably between the QHH and SZH cohorts. Very preterm infants born in QHH have higher odds of mortality or severe morbidity compared with those born in SZH.

Comprehensive Assessment of Houttuynia cordata Thunb., an Important Medicinal Plant and Vegetable

Houttuynia cordata Thunb., called Yuxingcao in Chinese, is an important medicinal plant and vegetable consumed in the southern regions of China. This review aims to summarize studies on the phyto-physiological chemistry, cytology, molecular biology, and genomics of H. cordata. Studies on the physiology and biochemistry of H. cordata have grown over the past few decades. Phenotypic and agronomic traits, tissue culture, elemental analysis, photosynthetic studies, bioactive compound identification, and antioxidant research have been reported. Molecular biological studies, such as those of molecular markers, microRNAs, DNA variations, protein variations, and transcriptomes have also advanced. Recent studies have focused on the rDNA and chloroplast genome of this plant. This review could serve as a basis to perform the genetic breeding, genomic advance, and cultivation of this valuable diversified plant resource for medicinal applications and vegetable production.

Methodology for the Prediction of Water Gushing in Tunnels in Igneous Fracture Tectonic Zones: A Case Study of a Tunnel in Guangdong Province, China

The disaster of water gushing is very liable to occur when tunnels are built in the water-rich fracture structures in igneous rock areas. Different sources of water gushing result in different sizes of disaster. The safety of human life and property are in danger. For the prediction of water gushing in tunnels, the fuzzy clustering method was used to determine the source of the water gushing in this paper. The problem of subjectivity in traditional identification methods was solved by this method. On the basis of the fuzzy clustering method, dynamically changing parameters of the effective radius of the water gushing were introduced and regressed with the dynamic monitoring data and the hydrogeological survey results in an improved method for predicting water gushing. Then, an improved method for predicting water gushing, considering the source, was proposed. A deep underground, extra-long tunnel under construction in the igneous region of southern China was used to verify the soundness of this improved method. Research results showed that the water gushing into the tunnel had a low correlation with surface water with a similarity index of λmin=0.3967 in the results of the second test. The water came mainly from within the rock mass. The effective radius were jointly determined by the average thickness of the rock aquifer and water gushing time, together with a positive correlation. The period of water gushing was divided into three stages. The predictions had a good accuracy rate with an error of 10% or less. These results could provide a reference and theoretical support for site construction.

Exploring the Impacts of Data Source, Model Types and Spatial Scales on the Soil Organic Carbon Prediction: A Case Study in the Red Soil Hilly Region of Southern China

Rapid and accurate mapping of soil organic carbon (SOC) is of great significance to understanding the spatial patterns of soil fertility and conducting soil carbon cycle research. Previous studies have dedicated considerable efforts to the spatial prediction of SOC content, but few have systematically quantified the effects of environmental covariates selection, the spatial scales and the model types on SOC prediction accuracy. Here, we spatially predicted SOC content through digital soil mapping (DSM) based on 186 topsoil (0–20 cm) samples in a typical hilly red soil region of southern China. Specifically, we first determined an optimal covariate set from different combinations of multiple environmental variables, including multi-sensor remote sensing images (Sentinel-1 and Sentinel-2), climate variables and DEM derivatives. Furthermore, we evaluated the impacts of spatial resolution (10 m, 30 m, 90 m, 250 m and 1000 m) of covariates and the model types (three linear and three non-linear machine learning techniques) on the SOC prediction. The results of the performance analysis showed that a combination of Sentinel-1/2-derived variables, climate and topographic predictors generated the best predictive performance. Among all variables, remote sensing covariates, especially Sentinel-2-derived predictors, were identified as the most important explanatory variables controlling the variability of SOC content. Moreover, the prediction accuracy declined significantly with the increased spatial scales and achieved the highest using the XGBoost model at 10 m resolution. Notably, non-linear machine learners yielded superior predictive capability in contrast with linear models in predicting SOC. Overall, our findings revealed that the optimal combination of predictor variables, spatial resolution and modeling techniques could considerably improve the prediction accuracy of the SOC content. Particularly, freely accessible Sentinel series satellites showed great potential in high-resolution digital mapping of soil properties.