Search

Reconstructing the role of provenance and transport mechanism of sediments deposited in deep-water environments is often complex because of myriad of factors such as variability in sediment sources, tectonics, bottom morphology, climatic changes and sea level fluctuations as well as current regime. The South China Sea (SCS) is situated at the tectonic intersection of the Pacific, Eurasian, and Indo-Australian plates, and provides an excellent natural laboratory for understanding source-to-sink transport processes of fluvial sediments. The Qiongdongnan Basin (QDNB) is located in the northern part of the SCS, and the deep-water area (>300 m) of the QDNB has a good hydrocarbon source and hydrocarbon accumulation conditions with a tremendous thickness since the late Miocene-Quaternary. However, the complex sources and transport mechanisms of sediments in the QDNB are undefined. In previous study QDNB may have a major provenance or a mixture of sources. In this paper, the sediments of two cores from the deep-water area of QDNB have been analyzed using several sedimentological and geochemical approaches, including measurements of grain size distribution(433 samples), the occurrence of minerals, and trace element geochemistry(37 samples)as well as strontium and neodymium isotopes(20 samples).The granularity analysis results first show that the 19S37 core can be divided into three stages while the 19S40 core is divided into two stages by clear vertical variations in grain size characteristics. Chlorite (62.0%) and Muscovite (33.6%) appear to be the predominant minerals in the 19S37 core, while the mineral assemblage of sediments from 19S40 mainly consists of kaolinite (37.4%), muscovite (29.2%) and chlorite (27.1%). The primitive mantle standardization curves and chondrite standardized distribution patterns of 19S37 and 19S40 are consistent and display enrichments in Th, U, Pb, and Nd and depletions in Ba, Nb, Sr, and Eu. In addition, the content of Sr fluctuates greatly with depth, which should reflect the influences of sea level changes and the relative proportion of various provenance components. The 143Nd/144Nd ratios and εNd values of the sediments from 19S37 are higher than those of the sediments from 19S40, and all the εNd values show narrow variations and range from −10.085 to −11.080. We conclude that the sediments of the deep-water area in the upper Pleistocene-Holocene were mainly from the sources of the Red River, Taiwan, Pearl River, Hainan Island, and Vietnam. The transport mechanism of the sediments from Hainan Island can be explained by the short distance between the source region and the sedimentary site, while the large amounts of terrigenous sediment inputs derived from the Red River and advantageous morphology make the Red River the largest sediment source to cores 19S37 and 19S40. The transport distance and amount of Deep Water Current could be even more powerful to make Taiwan be the second largest source of modern sediments in QDNB. • 19S37 core can be divided into three stages while the 19S40 core is divided into two stages. • The sediment of the deep-water area QDNB is mainly from the sources of the Red River. • The Pearl River and Taiwan Island have significant contributions to the whole NSCS. • The deep-water current and shallower Kuroshio current are the main pathways. • Sediments from the Pearl River were mainly transported by the Guangdong Coastal Current. [ABSTRACT FROM AUTHOR]

Encouraging farmers to adopt biopesticides is a crucial strategy for protecting the ecological environment and achieving sustainable agricultural development. This study utilizes data from a micro-survey of 454 banana farmers from Hainan Province of China and employs a logit model to analyze the effects of aging, land fragmentation, and their interactions on farmers' adoption of biopesticides, as well as the heterogeneity of farmers in different household life cycles. The findings reveal that aging and land fragmentation both hinder biopesticide adoption, with farmers experiencing higher levels of aging and more fragmented land holdings being less likely to utilize biopesticides in banana production. Mechanism analysis uncovers an interaction effect between aging and land fragmentation that hampers biopesticide adoption. Furthermore, the effects of aging, land fragmentation, and their interaction on biopesticide adoption behavior vary across farmers in different family life cycles. Specifically, aging negatively affects biopesticide adoption behavior for farmers in support households, while land fragmentation negatively influences farmers in dependency and burden households. The interaction between aging and land fragmentation adversely affects farmers in burden households. Our findings highlight the importance of aging agricultural labor and land fragmentation to promote green agriculture in China and call for more relevant policies to encourage farmers with different household life cycles to adopt biopesticides in farming practices. [ABSTRACT FROM AUTHOR]

Soil quality is a critically important component of soil within ecosystems, and our understanding of soil quality variation and its driving factors in tropical forests is limited. This study collected soil samples at 0–20 cm depths from two typical tropical forests (tropical rainforest and rubber plantation) on Hainan Island, China's largest tropical island, during dry and rainy seasons. A soil quality index (SQI) using principal component analysis was applied to measure soil quality based on 21 soil properties. The soil properties' spatial and seasonal changes and their driving factors were simultaneously collected for a holistic analysis of the ecosystems. The results were summarized as follows: (i) The SQI of the rubber plantation decreased by 26.48% compared to the tropical rainforest on the island, while four soil properties investigated (soil pH, total phosphorus, cellulose decomposition, and actinomycetes) increased. (ii) The SQI of different soil types in the two tropical forests displayed an apparent discrepancy. Within the same soil type, the SQI of tropical rainforests showed no obvious differences, while there was a notable spatial discrepancy among rubber plantations in dispersed geographical positions belonging to varied climatic zones. (iii) The SQI of the tropical rainforest was significantly higher in the wet season than in the dry season. In contrast, there were no significant differences between the two seasons for rubber plantations, indicating that soil quality in the tropical rainforest was more sensitive to seasonal changes than soil quality in rubber plantations. Overall, we concluded that except for land use and soil type, spatial variability and seasonal pattern also played essential roles in soil quality on the tropical island. The results from the SQI are expected to provide novel information regarding the sustainable use of tropical forests on Hainan Island. [ABSTRACT FROM AUTHOR]

An unusually persistent and heavy rainfall event occurred in Hainan Island from 1 to 9 October 2010, in association with one extended tropical depression (TD) over the South China Sea (SCS). Based on rain-gauge precipitation, satellite altimetry, in situ Argo profile, air–sea enthalpy flux, and reanalysis data, this study investigates the impact of warm ocean anomalies in the SCS on the formation and intensification of the extended TD, and their reinforcing effect on TD-related heavy rainfall. The TD intensified and migrated northward to the vicinity of Hainan Island. A thicker-than-normal warm subsurface layer that was present beneath the positive sea surface temperature (SST) anomalies contained a sufficient upper-ocean heat content to effectively restrain the TD's self-induced SST cooling effect, and available enthalpy fluxes were therefore sufficient to support the maintenance of the TD. The composite analyses confirm the reinforcing effect of warm oceanic anomalies in the central SCS off the south-central coast of Vietnam on heavy rainfall in Hainan Island, with the composite precipitation of "Warm eddy" cases being significantly larger in Hainan Island and northern Vietnam than that of the "Normal" cases, using reanalysis and remote sensing precipitation data over 29 years (1993–2021). [ABSTRACT FROM AUTHOR]

For the first time, this study explored spatio-temporal variation in water quality and phytoplankton community structure in Changwang, Meishe, and Wuyuan Rivers in tropical Hainan Island, China. Phytoplankton samples and water were collected between March and December 2019 and analyzed using standard methods. Two-way ANOVA revealed significant spatial and seasonal variation in physico-chemical parameters (p < 0.05). Wuyuan had high TP (0.06 ± 0.04 mg L−1), TN (1.14 ± 0.71 mg L−1), NH4+-N (0.07 ± 0.09 mg L−1), Secchi depth (2.28 ± 3.79 m), salinity (3.60±5.50 ppt), and EC (332.50 ± 219.10 µS cm−1). At the same time, Meishe had high TP (0.07 ± 0.03 mg L−1), TN (1.04 ± 0.74 mg L−1), NH4+-N (0.07 ± 0.10 mg L−1), EC (327.61 ± 63.22 µS cm−1), and turbidity (40.25 ± 21.16 NTU). In terms of seasons, spring recorded high average TP, TN, NH4+-N, COD, and DO, while summer had a high temperature, Chl-a, salinity, and EC. Generally, the physico-chemical parameters met the China water quality standard limits (GB 3838–2002). Overall, 197 phytoplankton species belonging to Cyanophyta, Chlorophyta, Cryptophyta, Bacillariophyta, Pyrrophyta, Euglenophyta, Xanthophyta, and Chrysophyta were identified, with Cyanophyta being dominant. Phytoplankton density showed spatial changes varying from 18 × 106 cell L−1 to 84 × 106 cell L−1. The phytoplankton diversity ranged from 1.86 to 2.41, indicating a mesotrophic state. One-way ANOSIM showed no significant spatial dissimilarity in phytoplankton composition (R = 0.042, p = 0.771) but indicated a significant seasonal difference (R = 0.265, p = 0.001). Therefore, SIMPER analysis revealed that Lyngbya attenuata, Merismopedia tenuissima, Cyclotella sp., Merismopedia glauca, Merismopedia elegans, and Phormidium tenue contributed to the seasonal differences. Furthermore, CCA demonstrated that TP, TN, NH4+-N, COD, Chl-a, and Secchi depth greatly influenced the phytoplankton community. This study shows the spatio-temporal variation in water quality and phytoplankton communities, useful for managing riverine quality. [ABSTRACT FROM AUTHOR]

After Bakun proposed his hypothesis in 1990 regarding upwelling under climate change, researchers conducted intensive studies to obtain the trends, current status, and future predictions of upwelling. Numerous studies have mainly focused on four major upwelling areas, which are part of the Eastern Boundary Upwelling System (EBUS). However, despite its importance, little attention has been given to the marginal seas upwelling areas such as the South China Sea (SCS), Arabian Sea, Baltic Sea, and other small-scale upwelling locations. Here, we combined several published studies to develop a new synthesis describing climate change impacts on these areas. There had been uncertainty regarding the intensification of upwelling, depending on the locations, data type, and method used. For the SCS, Vietnam and the northern SCS showed intensifying upwelling trends, while the Taiwan Strait showed a decreasing trend. Separate studies in eastern Hainan and the Arabian Sea (Somali and Oman) showed contrasting results, where both increasing and decreasing trends of upwelling had been recorded. Like the SCS, the Baltic Sea showed different results for different areas as they found negative trends along the Polish, Latvian and Estonian, and positive trends along the Swedish coast of the Baltic Sea and the Finnish coast of the Gulf of Finland. While small scales upwelling in La Guajira and southern Java showed increasing and decreasing trends, respectively. All of these limited studies suggest that researchers need to conduct a lot more studies, including the future projection of upwelling, by using climate models to develop a new understanding of how the upwelling in the SCS responds to climate change. [ABSTRACT FROM AUTHOR]

We conducted a study to examine the growth and physiological changes in 12 different ecotypes of Sesuvium portulacastrum collected from Hainan Island in China. These ecotypes were subjected to different concentrations (0, 200, 400, and 600 mmol/L) of sodium chloride (NaCl) salt stress for 14 days. We also analyzed the expression of metabolic genes related to stress response. Under low salt stress, indicators such as plant height in region K (0 mmol/L: 45% and highest at 200 mmol/L: 80%), internode length (0 mmol/L: 0.38, 200 mmol/L: 0.87, 400 mmol/L: 0.25, and 600 mmol/L: 1.35), as well as leaf area, relative water content, fresh weight, and dry weight exhibited an overall increasing trend with the increase in salt concentration. However, as the salt concentration increased, these indicators showed a decreasing trend. Proline and malondialdehyde contents increased with higher salt concentrations. When the NaCl concentration was 400 mmol/L, MDA content in the leaves was highest in the regions E (196.23%), F (94.28%), J (170.10%), and K (136.08%) as compared to the control group, respectively. Most materials demonstrated a significant decrease in chlorophyll a, chlorophyll b, and total chlorophyll content compared to the control group. Furthermore, the ratio of chlorophyll a to chlorophyll b (Rab) varied among different materials. Using principal component analysis, we identified three ecotypes (L from Xinglong Village, Danzhou City; B from Shuigoupo Village, Lingshui County; and J from Haidongfang Park, Dongfang City) that represented high, medium, and low salt tolerance levels, respectively, based on the above growth and physiological indexes. To further investigate the expression changes of related genes at the transcriptional level, we employed qRT-PCR. The results showed that the relative expression of SpP5CS1, SpLOX1, and SpLOX1 genes increased with higher salt concentrations, which corresponded to the accumulation of proline and malondialdehyde content, respectively. However, the relative expression of SpCHL1a and SpCHL1b did not exhibit a consistent pattern. This study contributes to our understanding of the salt tolerance mechanism in the true halophyte S. portulacastrum, providing a solid theoretical foundation for further research in this field. [ABSTRACT FROM AUTHOR]

Data measured by the Digisonde at the low‐latitude station Hainan from 2003 to 2016 are statistically analyzed to specify the diurnal average variations of the bottom‐side F region ionospheric plasma velocity vector V. This is the first comprehensive analysis of Digisonde measurements of low latitude F region plasma velocities in the East Asian sector that use a database covering more than one solar cycle. The velocity components VN (Northward), VE (Eastward), and VZ (Upward) are analyzed for two levels of solar flux and two levels of geomagnetic activity, respectively. The diurnal variations of the average VZ show three positive peaks near the prereversal enhancement (PRE) period, pre‐midnight, and before sunrise, respectively, and a prominent valley in the early morning. The averaged VZ significantly increased with solar flux in the period of PRE during equinoxes, but it was only slightly affected by Kp. The VE component was westward in daytime and eastward in nighttime. The average eastward VE increased significantly with solar flux but decreased with Kp, whereas the average westward VE exhibited only a small variation with solar flux and Kp. The average VN was almost southward independent of solar flux and Kp. The plasma velocities over the Hainan station were mainly caused by the electric field and neutral wind. Our results show that the features of the vertical and meridional velocities over the Hainan station in the morning are associated with the formation of the equatorial ionization anomaly (EIA). Plain Language Summary: The ionospheric plasma drift has been studied with data from ground‐based observations for decades. However, there is no corresponding study for the east Asian sector. In 2002, a Digisonde named DPS‐4 was installed at the Hainan station which can directly measure the plasma velocities with Drift mode. Using the data from the DPS‐4 at Hainan, we perform a statistical study on the bottom‐side F region plasma velocities at two levels of F10.7 and two levels of Kp, respectively. The results show that the velocities are mainly caused by the electric field and neutral wind, and the VN and VZ components are associated with the EIA formation. We also compared our results with that measured by incoherent scatter radar at the Jicamarca station. Some statistical results are similar, but some are different in the Hainan station and Jicamarca station, though the locations, the observed altitudes, and the observation periods differ between the two stations. Key Points: Bottom‐side ionospheric plasma velocities in the East Asian sector are comprehensively analyzed using Drift mode data of the DigisondeStatistical features of ionospheric plasma velocities over the low latitude station Hainan for two levels of F10.7 and two levels of KpVelocities are mainly caused by the electric field and neutral wind. The VN and VZ components may be associated with the formation of EIA [ABSTRACT FROM AUTHOR]

Species of Pestalotiopsis were mainly introduced as endophytes, plant pathogens or saprobes from various hosts. In this study, ten strains were isolated from Ficus macrocarpa, Phoebe zhennan and Spatholobus suberectus in China. Based on multilocus phylogenies from the internal transcribed spacer (ITS), the partial translation elongation factor 1-alpha gene (tef1α) and the partial beta-tubulin gene (tub2), in conjunction with morphological characteristics, we describe three new species, viz., Pestalotiopsis ficicola sp. nov., P. phoebes sp. nov. and P. spatholobi sp. nov. [ABSTRACT FROM AUTHOR]

The genus Catatemnus Beier, 1932 is reported for the first time from China and includes six new species: C. huae sp. nov. from Hainan Island, C. laminosus sp. nov., C. ramus sp. nov., C. scaber sp. nov., and C. tengchongensis sp. nov. all from Yunnan Province, and C. tibetanus sp. nov. from Xizang Autonomous Region. Descriptions and illustrations of all the new species are provided. [ABSTRACT FROM AUTHOR]

Bacterial leaf streak (BLS) of rice is a severe disease caused by the bacterial pathogen Xanthomonas oryzae pv. oryzicola (Xoc) that has gradually become the fourth major disease on rice in some rice-growing regions in southern China. Previously, we isolated a Bacillus velezensis strain 504 that exhibited apparent antagonistic activity against the Xoc wild-type strain RS105, and found that B. velezensis 504 was a potential biocontrol agent for BLS. However, the underlying mechanisms of antagonism and biocontrol are not completely understood. Here we mine the genomic data of B. velezensis 504, and the comparative transcriptomic data of Xoc RS105 treated by the cell-free supernatants (CFSs) of B. velezensis 504 to define differentially expressed genes (DEGs). We show that B. velezensis 504 shares over 89% conserved genes with FZB42 and SQR9, two representative model strains of B. velezensis, but 504 is more closely related to FZB42 than SQR9, as well as B. velezensis 504 possesses the secondary metabolite gene clusters encoding the essential anti-Xoc agents difficidin and bacilysin. We conclude that approximately 77% of Xoc RS105 coding sequences are differentially expressed by the CFSs of B. velezensis 504, which significantly downregulates genes involved in signal transduction, oxidative phosphorylation, transmembrane transport, cell motility, cell division, DNA translation, and five physiological metabolisms, as well as depresses an additional set of virulence-associated genes encoding the type III secretion, type II secretion system, type VI secretion system, type IV pilus, lipopolysaccharides and exopolysaccharides. We also show that B. velezensis 504 is a potential biocontrol agent for bacterial blight of rice exhibiting relative control efficiencies over 70% on two susceptible cultivars, and can efficiently antagonize against some important plant pathogenic fungi including Colletotrichum siamense and C. australisinense that are thought to be the two dominant pathogenic species causing leaf anthracnose of rubber tree in Hainan province of China. B. velezensis 504 also harbors some characteristics of plant growth-promoting rhizobacterium such as secreting protease and siderophore, and stimulating plant growth. This study reveals the potential biocontrol mechanisms of B. velezensis against BLS, and also suggests that B. velezensis 504 is a versatile plant probiotic bacterium. [ABSTRACT FROM AUTHOR]

Three new genera and eleven new species are reported from Hainan Island, China. The new genera are Logunattus gen. nov., including L. dufui sp. nov. (♂), and the generotype L. libaii sp. nov. (♂♀), Qiongattus yuanyeae gen. et sp. nov. (♂♀), and Spiralembolus gen. nov., including the generotype S. yinggeling sp. nov. (♂♀), and S. yui sp. nov. (♂♀). Another six new species are Carrhotus qingzhaoae sp. nov. (♂♀), Gedea liangweii sp. nov. (♂♀), Heliophanoides moi sp. nov. (♂), Indopadilla songi sp. nov. (♂♀), Myrmarachne mixiaoqii sp. nov. (♂♀), and Nandicius shihaitaoi sp. nov. (♂♀). The unknown female of the endemic species, Pancorius hainanensis Song & Chai, 1991 is also described for the first time. Diagnostic photos of these species are provided. [ABSTRACT FROM AUTHOR]

This study investigates the treatment of coconut oil using thermosonic treatment in combination with green coffee beans. Under a defined ratio of coconut oil to green coffee beans, the effect of different thermosonic time on the quality parameters, active substance content, antioxidant capacity, and thermal oxidative stability of coconut oil were investigated as a strategy to potentially improve the quality of oil. Results showed that the β-sitosterol content of CCO (coconut coffee oil) treated with the thermal method combined with green coffee bean treatment reached up to 393.80 ± 11.13 mg/kg without affecting the lipid structure. In addition, DPPH clearance equivalents increased from 5.31 ± 1.30 mg EGCG/g to 71.34 ± 0.98 mg EGCG/g, and the ABTS clearance equivalent was 45.38 ± 0.87 mg EGCG/g versus 0 for the untreated sample. The improvement in thermal oxidation stability of treated coconut oil is also significant. The TG (Thermogravimetry) onset temperature was elevated from 277.97 °C to 335.08 °C and the induction time was elevated up to 24.73 ± 0.41 h from 5.17 ± 0.21 h. Thermosonic treatment in combination with green coffee beans is an ideal option to improve the quality of coconut oil. The results of this article provide new ideas for the development of plant-blended oil products and the new utilization of coconut oil and coffee beans. [ABSTRACT FROM AUTHOR]

In China, Hainan Island is a priority area for turtle conservation because of its biodiversity. Over the years, errors in turtle taxonomy and distribution have been made in the scientific literature, perpetuating into relevant laws and government documents and affecting conservation and management. In the present article, we describe the species of nonmarine turtles on Hainan Island, China, based on literature, museum specimens, and field surveys during the past 27 yrs. Historically, 23 nonmarine turtle species were recorded on Hainan Island. Among them, 9 species should be removed due to errors: 5 species are not naturally distributed on Hainan Island (Manouria impressa, Sacalia bealei, Cuora flavomarginata, Mauremys nigricans, and Mauremys reevesii), 3 are invalid hybrids (Ocadia philippeni, Sacalia pseudocellata, and Cuora serrata), and 1 is a synonym of another species (Mauremys megalocephala is a synonym of M. reevesii). In addition, of the 3 new species recorded from Hainan Island (Sacalia insulensis, Pelodiscus variegatus, and Pelodiscus parviformis), S. insulensis replaces Sacalia quadriocellata, P. variegatus is valid, and P. parviformis is likely an error. Therefore, there should be 12 nonmarine turtle species naturally found on Hainan Island: Platysternon megacephalum, Cuora galbinifrons, Cuora mouhotii, Cuora trifasciata, Geoemyda spengleri, Mauremys mutica, Mauremys sinensis, S. insulensis, Palea steindachneri, Pelochelys cantorii, Pelodiscus sinensis, and P. variegatus. Clarifying the presence and distribution of nonmarine turtle species will provide a reference for future research and practical guidance for conservation management on this turtle-rich island. [ABSTRACT FROM AUTHOR]

To explore the adaptation mechanism of Hainan medaka, Oryzias curvinotus, to salinity, this study performed a histological and RNA‐Seq comparative analysis of female medaka liver with different salinities (0, 15 and 30 practical salinity unit [psu]). In the 30 psu group, the volume of hepatocytes was increased and cytoplasmic fat accumulated. A total of 83,758 unigenes were assembled by RNA‐Seq, of which 31,147 were annotated. In total, 922 differentially expressed genes (DEGs) were obtained, and the detection results of 24 DEGs by quantitative polymerase chain reaction (qPCR) were consistent with the RNA‐Seq data. Gene ontology (GO) enrichment showed that DEGs were mainly involved in biological processes, such as substance synthesis and transport, energy metabolism, signal transduction, and had catalytic activity and binding functions. Kyoto Encyclopedia of Genes and Genomes enrichment analysis showed that DEGs were significantly enriched in steroid biosynthesis, glycerophospholipid metabolism, peroxisome proliferator‐activated receptor signaling pathway, and insulin signaling pathway that regulate lipid metabolism. The results of this study highlight the response of the liver transcriptome to long‐term environmental salinity changes and provide a basis for the application of the medaka genetic resources. [ABSTRACT FROM AUTHOR]

According to the unified arrangement of Document No. 12 of 2018 issued by the Central Committee of Communist Party of China (CPC) and the State Council, the first free trade port (FTP) with Chinese characteristics was to be built in Hainan. Certain difficulties and challenges will inevitably arise during the building of the port, including lack of a unified foreign trade structure, low added value for the tourism industry, low utilization rate of foreign investment, and lack of innovation and openness within the financial industry. However, Hainan also enjoys certain advantages that are conducive to the building of a FTP, such as the existence of its natural outlying islands, a sound ecological environment, experience in reform and innovation of special economic zones, and policy support from the central government, as well as other basic conditions beneficial to the construction of such a port. Hainan must learn from the successful experience of other international FTPs in areas such as trade regulation, business environment, port clearance, financial openness, and fiscal and tax policies. It will be necessary for China to benchmark not only against the highest international standards but also to focus on positioning by differentiated functions, lay a solid foundation for development and transcend policy incentives, make up for financial shortcomings, encourage financial openness and innovation, and carry out differentiated fiscal and tax policies. At the same time, the division of powers and functions between the central and local governments must be properly handled, and an integrated administrative organization that promotes collaboration between the central and local governments must be established. [ABSTRACT FROM AUTHOR]

Background: Lifelong premature ejaculation (LPE) is one of the most common ejaculatory dysfunctions in men. The serotonin (5-HT) synthesis rate-limiting enzyme (TPH2) and receptor (HTR1A) in the 5-HT regulatory system may play a key role in the pathogenesis of LPE. However, there are few studies on the effects of TPH2 and HTR1A polymorphisms on LPE risk. We speculated that TPH2 and HTR1A polymorphisms may affect the occurrence and development of LPE in the Chinese Han population. Methods: In this study, 91 patients with LPE and 362 normal controls aged 18 to 64 years were enrolled in the male urology department of Hainan General Hospital in China from January 2016 to December 2018. The SNPs in HTR1A and TPH2, which are related to 5-HT regulation, were selected as indexes to genotype the collected blood samples of participants. Logistic regression was used to analyze the correlation between SNPs of HTR1A and TPH2 with LPE susceptibility, as well as the relationship with leptin, 5-HT and folic acid levels. Results: The results revealed that HTR1A-rs6295 increased LPE risk in recessive model. Rs11178996 in TPH2 significantly reduced susceptibility to LPE in allelic (odds ratio (OR) = 0.68, 95% confidence interval (95% CI) = 0.49–0.96, p = 0.027), codominant (OR = 0.58, 95% CI = 0.35–0.98, p = 0.040), dominant (OR = 0.58, 95% CI = 0.36–0.92, p = 0.020), and additive (OR = 0.71, 95% CI = 0.52–0.98, p = 0.039) models. Grs11179041Trs10879352 could reduce the risk of LPE (OR = 0.44, 95% CI = 0.22–0.90, p = 0.024) by haplotype analysis. Conclusion: HTR1A-rs6295 and TPH2-rs11178996 are associated with LPE risk in the Chinese Han population based on the finding of this study. [ABSTRACT FROM AUTHOR]

Nanolobatone A, featuring an unprecedented tricyclo[10.3.0.01,2]pentadecane carbon skeleton, along with four new polyoxygenated and four unusual endoperoxide‐bridged casbane‐type diterpenoids were isolated from the Hainan soft coral Sinularia nanolobata. The structures of the new compounds were established by extensive spectroscopic analysis, X‐ray diffraction analysis, and time‐dependent density functional theory/electronic circular dichroism calculations. A plausible biosynthetic pathway of new isolates was proposed. Bioassays revealed that nanolobatone A showed weak antibacterial activity against the Gram‐positive bacteria Streptococcus pyogenes. [ABSTRACT FROM AUTHOR]

Promoting the use of zero-emission vehicles is an important measure for reducing pollutant and carbon dioxide emissions from medium- and heavy-duty trucks (MHDTs). This study took Hainan Island as an example. Based on big data such as industrial layout and traffic flow, it clarified that the main channels of freight transportation on Hainan Island are concentrated in the northern region, including the surrounding areas of Haikou; the important ports of Haikou, Yangpu, and Basuo; and Chengmai and Tunchang counties. Furthermore, pathways for the promotion of zero-emission MHDTs are proposed, which can reduce exhaust emissions by 1549 tons of NOx, 62 tons of particulate matter (PM), and 3.60 million tons of CO2 by 2030. Compared with the vehicle type categorization plan, the spatial layout plan can achieve higher emission reduction benefits in the medium term (2025). In addition, in conjunction with existing policies and planning requirements, this study also puts forward policy suggestions for the promotion of zero-emission MHDTs. [ABSTRACT FROM AUTHOR]

The Papilionoideae is one taxonomically complex subfamily with high economic and medicinal potential. The pollen micro-morphology and taxonomic relevance of this subfamily are still poorly known in the island. Therefore, this study aims to provide new palynological information to correctly identify and define species boundaries within the subfamily. The species were collected from different geographical regions of Hainan Island. Both light and scanning electron microscopic techniques were used to observe pollen traits. Additionally, principal component analysis was performed to elucidate the variation among the taxa. A significant variation was found in exine sculpturing i.e. most of the taxa have reticulate type pollen while Desmodium triflorum has a psilate exine pattern. Variations were found on the surface of the reticula that can help to delimit the species from one another. Pollen type was observed as tricolporate and rarely tricolpate. Similarly, the colpus surface membrane morphology may also vary significantly from species to species i.e. scabrate, verrucate, gemmate, rugulate patterns. Besides, the mergo having various sculpturing found in Canavalia rosea, Desmodium triflorum, D. microphyllum Glycine max, Macroptilium atropurpureum, Erythrina crista-galli and Zornia gibbosa should be considered as a potential taxonomic trait for the subfamily. The maximum P/E ratio was found in Zornia gibbosa (2.24). Similarly, the maximum pollen size was found in Alysicarpus vaginalis (34.64 × 33.99 µm). Our study explored the pollen morphological traits and can be helpful to correctly identify the species and define species boundaries within Papilionoideae at various taxonomic levels. This study strengthens and supports the taxonomic position of the subfamily and will provide bases for further phylogenetic and molecular studies of Papilionoideae. Various taxa of the subfamily Papilionoideae were collected from different geographical regions of Hainan Island, South China. Both light and scanning electron microscopic techniques were used to analyze the ultra-sculpturing of the pollen. Most of the taxa have reticulate exine patterns but variations were found in supra-tectal elements and colpus surface membrane morphology. These variations in pollen traits have significant taxonomic potential and will strengthen the taxonomy of Papilionoideae. This study can help to correctly identify and define species boundaries at various taxonomic levels of the Papilionoideae and will solve the taxonomic problem. [ABSTRACT FROM AUTHOR]

The differences in cpDNA SNPs and InDels of 13 samples from single trees of different species or populations of oil-tea camellia in South China were examined in this study, and phylogenetic trees were reconstructed based on CDSs and non-CDSs of cpDNAs to research the evolutionary relationships among all samples. The SNPs of all samples included all kinds of substitutions, and the frequency of the transition from AT to GC was highest; meanwhile, the frequencies of all kinds of transversions differed among the samples, and the SNPs exhibited polymorphism. The SNPs were distributed in all the different functional regions of cpDNAs, and approximately half of all SNPs in exons led to missense mutations and the gain or loss of termination codons. There were no InDels in the exons of any cpDNA samples, except those retrieved from Camellia gigantocarpa, although this InDel did not lead to a frame shift. The InDels of all cpDNA samples were unevenly distributed in the intergenic region and upstream and downstream of genes. The genes, regions of the same gene, sites and mutation types in the same region related to the distributions of SNPs, and InDels were inconsistent among samples. The 13 samples were divided into 2 clades and 7 or 6 subclades, and the samples of species from the same sections of the Camellia genus did not belong to the same subclades. Meanwhile, the genetic relationship between the samples of Camellia vietnamensis and the undetermined species from Hainan Province or the population of C. gauchowensis in Xuwen was closer than that between C. vietnamensis and the population of C. gauchowensis in Luchuan, and the genetic relationship among C. osmantha, C. vietnamensis and C. gauchowensis was very close. In sum, SNPs and InDels in the different cpDNAs resulted in variable phenotypes among the different species or populations, and they could be developed into molecular markers for studies on species and population identification and phylogenetic relationships. The conclusion from the identification of undetermined species from Hainan Province and the phylogenetic relationships among 13 oil-tea camellia samples based on cpCDS and cpnon-CDS sequences were the same as those from the former report. [ABSTRACT FROM AUTHOR]

The coastal zone area of Qionghai City is one of the important coastal zones in the South China Sea, and its water environment has been affected by human activities such as urbanization and industrialization. In order to protect the water resources and ecological environment of this area, the water chemistry characteristics of the main watersheds and their causes in the coastal zone area of eastern Hainan Island were investigated to provide a scientific basis for environmental protection and sustainable development. In this study, the characteristics and sources of water chemical ion components were analyzed using a Piper trilinear diagram, Gibbs diagram, and correlation analysis with the coastal zone area of Qionghai city as the research object. The results show the following: (1) the dominant cation of water chemistry in the coastal zone of Qionghai City is Na+ with a mean value of 35.001 mg·L−1, and the dominant anion is Cl− with a mean value of 30.69 mg·L−1; (2) the dominant cation content in the coastal zone of Qionghai City is Na+ > Ca2+ > Mg2+ > K+, and the dominant anion content is Cl− > SO42− > HCO3− > CO32−; (3) at the five collection sites in the study area, the ion concentrations showed different trends, with the highest ion concentration in the water samples collected from aquaculture ponds, and the main water chemistry type was Na-Cl; the lowest ion concentration was in the water samples collected from the rivers, and the main type of water chemistry was Ca·Mg-HCO3. The source of water chemistry ions in the study area mainly included seawater, rock weathering, atmospheric precipitation, and evaporation concentration. The results of this study can provide a scientific basis for the development, utilization, and management of local water resources and provide basic data for environmental protection and sustainable development. [ABSTRACT FROM AUTHOR]

Camellia oleifera C.Abel, commonly known as tea-oil camellia, is a type of significant woody oil crop that is widely cultivated in southern China. During 2017–2021, a fungal foliar disease was detected in routine surveys in Hainan. However, diseases of tea-oil camellia are seldom reported in Hainan. In this study, 51 Colletotrichum spp. isolates were obtained from the symptomatic samples of tea-oil camellia, collected from three production sites located in Hainan. A polyphasic approach was applied to distinguish Colletotrichum species. All 51 isolates were primarily characterized morphologically, and six gene regions, including an internally transcribed space of ribosomal DNA (ITS), chitinsynthase (CHS-1), β-tubulin (TUB), actin (ACT), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and manganese-superoxide (SOD2), were sequenced for each isolate. By combining morphological characterization with multilocus sequence analysis (MLSA) based on the six genes, the fungal isolates were identified, representing three Colletrotrichum species: C. fructicola, C. siamense, and C. cordylinicola. The most predominant species was C. fructicola. In pathogenicity tests on the tea-oil camellia cultivar (Reyan1), all collected isolates were pathogenic on tea-oil camellia leaves and were reisolated from symptomatic leaves. Colletotrichum fructicola was the most aggressive species on the attached leaves. This is the first report of C. cordylinicola affecting tea-oil camellia anthracnose worldwide. These results will improve our understanding of the pathogens and provide important insights on the diagnosis and efficient disease management of tea-oil camellia anthracnose. [ABSTRACT FROM AUTHOR]

The congruity between projected and perceived destination images is decisive to the success of destination marketing. However, existing studies focused on bridging the dissonance have limitations regarding the target market definition and the depth of the image contrast. This study focuses on the unique marketing context of Hainan, China, to attract repeat tourists and compares the destination's 'projected-perceived' image networks. The differences in the network characteristics, important nodes, network paths, and subgroups between the two networks are identified. The theoretical implications of the new concept of image contrast and management and the practical implications of achieving congruity between the image networks are provided. [ABSTRACT FROM AUTHOR]

In order to reduce the occurrence of soil-borne diseases, such as tomato bacterial wilt and Fusarium wilt, and to improve the yield of cherry tomato in Hainan, the paper had summarized grafting and seedling technology of cherry tomato from the aspects of rootstock selection, rootstock seedling cultivation, scion seedling cultivation, preparation before grafting, grafting method and seedling management after grafting. It was found that the technique could significantly improve the yield and disease resistance of cherry tomato. [ABSTRACT FROM AUTHOR]

This study uses numerical simulations to investigate the impact of cross-scale interaction between the cold air pool (CAP) and the synoptic systems on autumnal nighttime rain over Hainan Island. The results show that the precipitation formed initially via the convergence of the southerly wind from a mesoscale vortex located around the Beibu Gulf and the sea breeze along the northwest coast of Hainan Island in the afternoon. Subsequently, this precipitation propagated eastward due to the weakening and southward movement of the vortex, which was promoted by the CAP that formed in the lower troposphere within 2 h after rainfall. The CAP weakened the vortex by forming a sub-2-km divergent wind and accelerating upward propagation of the positive potential vorticity. And the CAP promoted the southward movement of the vortex by increasing the sea level pressure on its northeast side and stimulating a cyclonic disturbance on its southeast side, which was also conducive to the southward shift of cold air from the Chinese mainland. When the cold air arrived at Hainan Island at night, it was deepened by the blocking effect of the sub-2-km divergent wind. The superposition of the blocked cold air and the CAP stimulated a strong northerly land breeze, which merged with the southerly wind to reinvigorate rainfall in the eastern coastal area. This paper reveals the mechanism by which the CAP affects the heavy rainfall at night on Hainan Island in autumn under the combined influence of the tropical disturbance-related vortex and the cold air from the north. • The cold air pool (CAP) can strengthen effectively the autumnal nighttime rainfall on Hainan Island. • The CAP strengthens the rainfall by modulating mesoscale synoptic systems. • The CAP promotes the weakening and southward movement of the mesoscale vortex. • The cold air reaching Hainan Island will be strengthened by the blocking effect of the CAP. [ABSTRACT FROM AUTHOR]

Protecting water tower cities benefits human life, global ecosystems, and the development of agriculture and industry. Hainan Tibetan Autonomous Prefecture, a typical water tower city, is an important water conservation area on the Qinghai-Tibet Plateau. This paper outlines the history of Hainan and demonstrates how different policies influence the development of its environment, economy, and society. To date, Hainan has made full use of climate and natural resources and cultural advantages to establish a model of sustainability in which economic, social, and cultural development dimensions have interactive relationships. The Hainan model can be described as a development path, which can be generalized to a universal version, the water tower cities model, that can be applied to other water tower cities, including "pan-third pole" areas worldwide. The model encourages water tower cities to deeply tap into the unique advantages of urban geographical and cultural development as the driving force of urban economic, social and environmental dimensions. Thus, high altitude, river resources, and other unique characteristics have mutual effects, which will underpin the movement of the water tower city toward more sustainable development. • Hainan Prefecture, water source of high-altitude mountains, is a water tower city. • How Hainan Prefecture achieves sustainable development is examined. • Transforming urban characteristics to endogenous power can enhance sustainability. • Urban sustainability relies on mutual supports from various industries. • An urban sustainability model for water tower cities is proposed. [ABSTRACT FROM AUTHOR]

Agro-ecosystem contamination with microplastics (MPs) is of great concern. However, limited research has been conducted on the agricultural soil of tropical regions. This paper investigated MPs in the agro-ecosystem of Hainan Island, China, as well as their relationships with plastic mulching, farming practices, and social and environmental factors. The concentration of MPs in the study area ranged from 2800 to 82500 particles/kg with a mean concentration of 15461.52 particles/kg. MPs with sizes between 20 and 200 μm had the highest abundance of 57.57%, fragment (58.16%) was the most predominant shape, while black (77.76%) was the most abundant MP colour. Polyethylene (PE) (71.04%) and polypropylene (PP) (19.83%) were the main types of polymers. The mean abundance of MPs was significantly positively correlated (p < 0.01) with all sizes, temperature, and shapes except fibre, while weakly positively correlated with the population (p = 0.21), GDP (p = 0.33), and annual precipitation (p = 0.66). In conclusion, plastic mulching contributed to significant contamination of soil MPs in the study area, while environmental and social factors promoted soil MPs fragmentation. The current study results indicate serious contamination with MPs, which poses a concern regarding ecological and environmental safety. [Display omitted] • Abundance and spatial distribution of MPs were analyzed in agriculture soil. • Most of the MPs in soil of Hainan were fragments and < 500 μm in size. • PE was the most abundant polymer observed in the study area. • MPs distribution was site specific with no strong relation with crops. • Plastic mulching was the main source of MPs in soil. [ABSTRACT FROM AUTHOR]

Drownings due to rip currents are a major threat to beach safety. In this study a high-resolution Boussinesq model with a modified wave-resolving Lagrangian tracking module has been applied to a 2-km-long embayed beach, Dadonghai of Sanya, Hainan Island, with the purpose to study rip current variability, real-time rip hazard identification, and the optimal swimmer escape strategies. Beach stage plays an important role in the occurrence and strength of rip currents. Satellite images of the Dadonghai Beach shows that crescentic bars and shore-connected transverse bars emerge alternatively in the embayed beach, which results in long-term modulation of rip strength periodically according to the modeling. A series of tests are designed and confirms that rip current strength is closely related to wave properties and tidal levels. Spectral analysis of output time series at specific points shows that rip currents fluctuate on the orders of 1 min and 10 min, which reflects the effects of wave-group and VLF (Very Low Frequency) motions. Real-time evaluation of rip hazard is crucial for providing the lifeguards and general public with appropriate information on the occurrence and location of the rip currents, and how to set patrolled area. However, fine-scale numerical modeling using the existing hydrodynamic models are computing-demanding due to a cascade of basin-scale meteorological and wave climate modeling down to the wave-resolving scale. In this study, an attempt of using GPU-accelerated Boussinesq model embedded with the spectral wave model (WAM6) has been made, which enables a faster and more complete description of rip hazard. Lagrangian tracking of virtual swimmers demonstrates that multiple factors contributing to the survival of swimmers caught in the rip currents, include surf-zone bathymetry, rip strength, flow patterns, and swimmer's position. For weak-to-moderate rip currents and longshore currents, swim onshore consistently seems the most successful strategy across all the scenarios in this study. For swimmers within the inner surf zone, the successful rate is satisfactory by taking strategies of either swim onshore or swim parallel to the beach. Higher surf-zone exit rate along the Dadonghai Beach are not favorable to stay afloat action, which put swimmers at a higher risk of being expelled to deeper water. Pulsation of rip currents in wide rip channels can form swirls or eddies which can also be hazardous to swimmers with weak swimming ability. One of the differences of the present study from the previous works is that the random, wave-resolving modeling was adopted for Lagrangian tracking of virtual swimmers with 1-m resolution. Virtual trajectories yielded by the wave-resolving and wave-averaged velocities are generally consistent with each other. However, using Boussinesq model shows its superiority in studying fine-scale nearshore circulation and its variability, as well as understanding the effects of wave randomness and directional spreading on surf-zone flows. [ABSTRACT FROM AUTHOR]

The gross primary production (GPP) of the mangrove ecosystem determines the upper limit of the scale of its "blue carbon" sink. Tropical cyclones (TCs) are among the most important extreme events that threaten the subtropical mangrove ecosystem and have a serious impact on mangrove ecosystem GPP. However, there are somewhat insufficient scientific findings on regional-scale mangrove ecosystem GPP responding to large-scale weather events such as TCs. Therefore, we selected the subtropical Hainan Island mangrove ecosystem, where more than two TCs pass through per year, as the research area; selected direct-attack TCs as the research object; and took the mangrove vegetation photosynthesis light-use efficiency model established based on the eddy covariance observation data as the tool to evaluate the loss and recovery of mangrove ecosystem GPP after TCs attacked at a regional scale. We found that the TC impacted the mangrove ecosystem GPP through the photosynthetic area and rate, and the recovery of the rate occurred prior to the recovery of the area; the loss of mangrove ecosystem GPP is inversely proportional to the distance to the center of the TC and the distance to the coastline; and the canopy height, diameter at breast height, and aspect where the tree stands significantly influence the response of the mangrove ecosystem GPP to TCs. However, the response varies for different mangrove community compositions, soil conditions, and planting densities as well as different frequencies and intensities of TCs, and they should be analyzed in detail. This study is expected to provide technical and data support for the protection of blue carbon in a subtropical island mangrove ecosystem in response to extreme events and post-disaster recovery. [ABSTRACT FROM AUTHOR]

Promoting green development and promoting harmonious coexistence between humans and nature are strategic tasks for the construction of ecological civilization in China in the new era. Currently, the growing environmental governance investment in China has not performed well, and the low efficiency of environmental governance has become the main problem facing the development of ecological civilization in China. Therefore, it is of great practical significance to scientifically measure the efficiency of environmental governance and improve the efficiency of environmental governance input factors to achieve green development and overcome the difficulties in the construction of ecological civilization. In this study, an improved three-stage SBM model and cloud model combined with the Theory of production, life, and ecology were used to measure the environmental governance efficiency of 27 provinces in China from 2003 to 2020 and conduct in-depth analysis and evaluation. The results show that: First, the influence of random error factors and external environmental conditions on the efficiency of rural domestic sewage treatment in China is significant. Their existence will underestimate the environmental governance efficiency in the central and western regions of China and overestimate the environmental governance efficiency in the eastern regions of China, except for Hainan Province. Second, after excluding the influence of random errors and external environment conditions, the adjusted efficiency mean value of the central and western regions significantly increases, while the environmental governance efficiency of most provinces in the eastern region, except for Hainan Province, decreases significantly. Third, the overall environmental governance efficiency of the 27 provinces in China still presents a situation wherein the western region is ranked first in efficiency, the eastern region ranks second, and the central region ranks third. The environmental governance efficiency of the 27 provinces shows a "large at both ends, small in the middle" and "low efficiency in the eastern and central regions, and instability in the western region" state, and there is a large difference in the degree of environmental governance efficiency among the various provinces. In this regard, for the eastern and central regions, special attention should be paid to their government's transformation of development thinking, placing greater emphasis on balanced and coordinated development between urbanization, industrialization, and the environment. As for the western region, due to its harsh environmental conditions, it attaches more importance to environmental governance. However, efforts should be made to strengthen its economic development to ensure sufficient provision of material conditions such as infrastructure and equipment required for environmental governance in order to achieve stable environmental governance efficiency in the western region. For the central region, both the economy and the environment need to be further strengthened. [ABSTRACT FROM AUTHOR]

Staurogyne concinnula (Hance) O. Kuntze (Acanthaceae) is an important ornamental herb mainly distributed in the southern region of China, including Fujian, Guangdong, Hainan, and Taiwan provinces. However, the complete chloroplast genome of S. concinnula, which could serve as a genetic resource for studies on its taxonomy and evolution, is poorly studied at present. In this study, we reported the complete chloroplast genome of S. concinnula that was assembled using high-throughput sequencing data. The chloroplast genome was 153,783 bp long, with a typical quadripartite structure containing a small single-copy region (SSC; 17,855 bp), a large single-copy region (LSC; 84,636 bp) and a pair of inverted repeats (IRs; each 25,646 bp). The overall GC content of the chloroplast genome was 38.04%. A total of 86 protein-coding genes (PCGs), 8 rRNA genes, and 37 tRNA genes were predicted. Phylogenetic analysis based on the combined sequences of 86 PCGs with the other 16 closely related species of Acanthaceae indicated that S. concinnula is closely related to Avicennia marina. The genomic data and finding from the phylogenetic studies of S. concinnula could provide useful information and give light to in-depth studies on the evolution pattern of the understudied species, as well as Staurogyne. [ABSTRACT FROM AUTHOR]

Freshwater on islands represents a precious resource and highly vulnerable ecosystem. For monitoring freshwater, satellite remote sensing is efficient and has large-scale application. This study proposed a modified model of the quasi-analytical algorithm (ZSD-QAAv6m) to retrieve the water clarity of inland waters (>1 km2) across Hainan Island, China using Sentinel-2 multispectral instrument data. By adjusting the threshold of Rrs(665), the proposed model could accurately estimate water clarity with diverse optical properties on the island and avoid underestimation in moderately clear waters. Based upon this, the first spatiotemporal analysis of recent water clarity in Hainan Island was conducted. The results show that lake water clarity in the central region was generally higher (with average value of 1.4 m) than that of coastal regions (with average value of 1.2 m). Seasonally, the water clarity during the wet season was usually lower than that in the dry season, with average values of 1.1 m and 1.3 m across the island respectively. From 2017 to 2021, the proportion of water bodies with water clarity > 0.5 m increased from 60% to 100%. The overall spatial pattern of water clarity was correlated to the regional vegetation cover in Hainan Island, with higher clarity associated with higher vegetation cover in the central regions. The seasonal variation of water clarity may be attributed to heavy rainfall and runoff during the wet season; while the distinct annual variation may be benefited from the strengthened surface water protections in Hainan Province in recent years. This study provides a practical approach for evaluating the SDG 6.3.2 indicator in Hainan Island using remote sensed water clarity as a comprehensive water quality indicator and the findings could facilitate the island's water resource management and conservation. [ABSTRACT FROM AUTHOR]

Applying the emerging molecular networking strategy, an uncommon cembranoid orthoester, sarcotortin A (1), featuring a 3/14/8/5‐fused scaffold, an unusual eunicellane‐type diterpenoid, sarcotorolide A (2), and two new biscembranoids, ximaolides M and N (7 and 8), along with nine known terpenoids 3–6 and 9–13 were isolated from the Hainan soft coral Sarcophyton tortuosum. The structure and absolute configuration of all new compounds were established by a combination of spectroscopic data, X‐ray diffraction analysis, and/or quantum chemical computational approaches. The plausible biogenetic relationship among these skeletally different terpenoids was proposed and discussed. In in vitro bioassay, new compound 7 exhibited a remarkable inhibitory activity against protein tyrosine phosphatases 1B (PTP1B) with the IC50 value of 8.06 μM. In addition, compounds 4 and 10 displayed significant inhibitory effects on lipopolysaccharide (LPS)‐induced inflammatory responses in RAW264.7 macrophages cells with the IC50 values of 19.13 and 16.45 μM, respectively. Compound 9 showed interesting cytotoxicity against H1975, MDA‐MB231, A549, and H1299 cancer cell lines with IC50 values of 31.59, 34.96, 43.87, and 27.93 μM, respectively. [ABSTRACT FROM AUTHOR]

Background: As one of the largest drupes in the world, the coconut has a special multilayered structure and a seed development process that is not yet fully understood. On the one hand, the special structure of the coconut pericarp prevents the development of external damage to the coconut fruit, and on the other hand, the thickness of the coconut shell makes it difficult to observe the development of bacteria inside it. In addition, coconut takes about 1 year to progress from pollination to maturity. During the long development process, coconut development is vulnerable to natural disasters, cold waves, typhoons, etc. Therefore, nondestructive observation of the internal development process remains a highly important and challenging task. In this study, We proposed an intelligent system for building a three-dimensional (3D) quantitative imaging model of coconut fruit using Computed Tomography (CT) images. Cross-sectional images of coconut fruit were obtained by spiral CT scanning. Then a point cloud model was built by extracting 3D coordinate data and RGB values. The point cloud model was denoised using the cluster denoising method. Finally, a 3D quantitative model of a coconut fruit was established. Results: The innovations of this work are as follows. 1) Using CT scans, we obtained a total of 37,950 non-destructive internal growth change maps of various types of coconuts to establish a coconut data set called "CCID", which provides powerful graphical data support for coconut research. 2) Based on this data set, we built a coconut intelligence system. By inputting a batch of coconut images into a 3D point cloud map, the internal structure information can be ascertained, the entire contour can be drawn and rendered according to need, and the long diameter, short diameter and volume of the required structure can be obtained. We maintained quantitative observation on a batch of local Hainan coconuts for more than 3 months. With 40 coconuts as test cases, the high accuracy of the model generated by the system is proven. The system has a good application value and broad popularization prospects in the cultivation and optimization of coconut fruit. Conclusion: The evaluation results show that the 3D quantitative imaging model has high accuracy in capturing the internal development process of coconut fruits. The system can effectively assist growers in internal developmental observations and in structural data acquisition from coconut, thus providing decision-making support for improving the cultivation conditions of coconuts. [ABSTRACT FROM AUTHOR]

Introduction: Burkholderia pseudomallei is a gram-negative environmental bacterium and aetiological agent of melioidosis, a tropical infectious disease with diverse clinical presentations. We aimed to describe the epidemiological and clinical characteristics of melioidosis in northern Hainan and to determine the meteorological factors affecting its morbidity. Methods: We conducted a retrospective, multicentre, observational cohort study of 90 patients with melioidosis admitted to four general hospitals in northern Hainan from 2010 to 2020. Epidemiological, clinical presentation, laboratory and treatment outcome data were collected and analysed. The monthly incidence of melioidosis and meteorological data, including precipitation, temperature, humidity, air pressure and wind speed, for the same period were collected to analyse the relationship between meteorological factors and the incidence of melioidosis. Results: Of the 90 patients included in the study, 79 (87.78%) were male. Patient age ranged from 10 to 81 years old, but most patients, namely, 78 (86.67%), were middle-aged and elderly people aged 41–81 years old. Forty-six patients (51.11%) were farmers. The number of cases increased significantly after 2014, with the highest numbers occurring in 2014 and 2016. The highest number of cases occurred in summer and autumn and were associated with abundant rainfall, and 58 cases (64.44%) occurred from July to December. The patients showed diverse presentations and abnormal laboratory parameters: 69 patients (76.67%) had a history of diabetes mellitus; bacteremia was present in 50 patients (55.56%), sepsis was present in 39 patients (43.33%) and pneumonia in 19 patients (21.11%). An average high-sensitivity C-reactive protein (hs-CRP) level of 149.57 ± 13.65 mg/L and a median procalcitonin (PCT) level of 1.31 (0.39, 6.21) ng/mL were observed. Among all the cases, 21 (23.33%) were identified as acute infections, 51 (56.67%) as subacute infections and 18 (20.00%) as chronic infections. Six patients (6.67%) died of illness; five of these patients were male, and five of these patients were middle-aged and elderly patients. The monthly average precipitation was significantly positively correlated with the monthly average incidence of melioidosis (r = 0.74, P < 0.01). Conclusion: Male patients, farmers and especially middle-aged and elderly individuals with a history of diabetes mellitus accounted for most of the patients. The majority of cases were concentrated in coastal areas. Most cases of melioidosis occurred during the rainy seasons, and the monthly average precipitation was an independent factor affecting the average monthly incidence of melioidosis. [ABSTRACT FROM AUTHOR]

The leaf traits measured in multiple species are known to vary between seasons, but there is a knowledge gap relating to the seasonal variability and environmental adaptation of plants in tropical rainforests. To investigate the dynamics of the functional traits of dominant species in tropical rainforests and the differences in their adaptation strategies to seasonal drought, the results of this study can provide a scientific basis for tropical rainforest conservation resource protection. Six dominant species, including three trees (Hopea reticulata, Vatica mangachapoi, and Diospyros chunii) and three vine plants (Ancistrocladus tectorius, Phanera khasiana, and Uvaria sanyaensis), in tropical lowland rainforest in the Ganzaling Nature Reserve of Hainan province were selected as study objectives. The key leaf traits were studied using the paraffin section method, leaf epidermis segregation method, and Li-6400 portable photosynthesis system in June, September, December, 2019, and March, 2020. Results showed that significant differences in photosynthetic physiology and morphological and structural parameters among species, as well as seasonal variability, were observed in leaf photosynthetic physiology, but not in leaf morphological or structural parameters. A phenotypic plasticity index (PPI) analysis revealed more variability in leaf photosynthetic physiology (Average PPI = 0.37) than in leaf anatomical structure and morphology (Average PPI = 0.26), suggesting that they adapt to seasonal changes primarily by regulating photosynthetic physiological parameters rather than leaf morphology or anatomical structure. The dominant trees were found to have higher water use efficiency, leaf dry-matter content, and smaller leaf areas compared to vine plants. This indicates that the dominant tree species depend on high water use efficiency and leaf morphological characteristics to adapt to seasonal changes. The majority of leaf anatomical structure parameters associated with drought tolerance were higher in the three dominant vine species, indicating that the dominant vine species adapted to drought stress primarily by altering the leaf anatomical structure This study provides information on how tropical rainforest plants adapt to seasonal drought as well as supporting the protection of tropical rainforest ecosystems. [ABSTRACT FROM AUTHOR]

Using satellite observations from 2003 to 2020 and cruise observations from 2019 and 2021, this study reveals an unexpected minor role of upwelling in seasonal and interannual variations in chlorophyll a (Chl a) concentrations in the coastal upwelling region east of Hainan Island (UEH) in the northwestern South China Sea (NWSCS). The results show strong seasonal and interannual variability in the Chl a concentration in the core upwelling area of the UEH. Different from the strongest upwelling in summer, the Chl a concentration in the UEH area reaches a maximum of 1.18 mg m -3 in autumn and winter, with a minimum value of 0.74 mg m -3 in summer. The Chl a concentration in summer increases to as high as 1.0 mg m -3 with weak upwelling, whereas the maximum Chl a concentration in October increases to 2.5 mg m -3. The analysis of environmental factors shows that, compared to the limited effects of upwelling, the along-shelf coastal current from the northern shelf and the increased precipitation are crucially important to the Chl a concentration variation in the study area. These results provide new insights for predicting marine productivity in upwelling areas, i.e., multiple mechanisms, especially horizontal advection, should be considered in addition to the upwelling process. [ABSTRACT FROM AUTHOR]

Understanding the water use efficiency (WUE) and adaptation strategies of plants in high-temperature and rainy areas is essential under global climate change. The leaf carbon content (LCC) and intrinsic WUE of 424 plant samples (from 312 plant species) on Hainan Island were measured to examine their relationship with geographical and climatic factors in herbs, trees, vines and ferns. The LCC ranged from 306.30 to 559.20 mg g−1, with an average of 418.85 mg g−1, and decreased with increasing mean annual temperature (MAT). The range of intrinsic WUE was 8.61 to 123.39 μmol mol−1 with an average value of 60.66 μmol mol−1. The intrinsic WUE decreased with increasing altitude and relative humidity (RH) and wind speed (WS), but increased with increasing latitude, MAT and rainy season temperature (RST), indicating that geographical and climatic factors affect the intrinsic WUE. Stepwise regression suggested that in tropical regions with high temperature and humidity, the change in plant intrinsic WUE was mainly driven by WS. In addition, the main factors affecting the intrinsic WUE of different plant functional types of plants are unique, implying that plants of different plant functional types have distinctive adaptive strategies to environmental change. The present study may provide an insight in water management in tropical rainforest. [ABSTRACT FROM AUTHOR]

Background: The cytoplasmic male sterility (CMS) of rice is caused by chimeric mitochondrial DNA (mtDNA) that is maternally inherited in the majority of multicellular organisms. Wild rice (Oryza rufipogon Griff.) has been regarded as the ancestral progenitor of Asian cultivated rice (Oryza sativa L.). To investigate the distribution of original CMS source, and explore the origin of gametophytic CMS gene, a total of 427 individuals with seventeen representative populations of O. rufipogon were collected in from Dongxiang of Jiangxi Province to Sanya of Hainan Province, China, for the PCR amplification of atp6, orfH79 and B-atp6-orfH79, respectively. Results: The B-atp6-orfH79 and its variants (B-atp6-GSV) were detected in five among seventeen populations (i.e. HK, GZ, PS, TL and YJ) through PCR amplification, which could be divided into three haplotypes, i.e., BH1, BH2, and BH3. The BH2 haplotype was identical to B-atp6-orfH79, while the BH1 and BH3 were the novel haplotypes of B-atp6-GSV. Combined with the high-homology sequences in GenBank, a total of eighteen haplotypes have been revealed, only with ten haplotypes in orfH79 and its variants (GSV) that belong to three species (i.e. O. rufipogon, Oryza nivara and Oryza sativa). Enough haplotypes clearly demonstrated the uniform structural characteristics of the B-atp6-orfH79 as follows: except for the conserved sequence (671 bp) composed of B-atp6 (619 bp) and the downstream followed the B-atp6 (52 bp, DS), and GSV sequence, a rich variable sequence (VS, 176 bp) lies between the DS and GSV with five insertion or deletion and more than 30 single nucleotide polymorphism. Maximum likelihood analysis showed that eighteen haplotypes formed three clades with high support rate. The hierarchical analysis of molecular variance (AMOVA) indicated the occurrence of variation among all populations (FST = 1; P < 0.001), which implied that the chimeric structure occurred independently. Three haplotypes (i.e., H1, H2 and H3) were detected by the primer of orfH79, which were identical to the GVS in B-atp6-GVS structure, respectively. All seventeen haplotypes of the orfH79, belonged to six species based on our results and the existing references. Seven existed single nucleotide polymorphism in GSV section can be translated into eleven various amino acid sequences. Conclusions: Generally, this study, indicating that orfH79 was always accompanied by the B-atp6, not only provide two original CMS sources for rice breeding, but also confirm the uniform structure of B-atp-orfH79, which contribute to revealing the origin of rice gametophytic CMS genes, and the reason about frequent recombination of mitochondrial DNA. [ABSTRACT FROM AUTHOR]

Airglow observation is a very effective method to investigate plasma bubbles, and can obtain their horizontal structure. In this study, the image processing method was used to process airglow data, including image enhancement, azimuth correction, and image projection, and the clear image products of equatorial plasma bubbles (EPBs) were obtained. Based on the optical data of the airglow imager in Hainan, we investigated the main optical features of EPBs, and statistically analyzed the occurrence of EPBs from September 2014 to August 2015. The observation results show that EPB exhibits plume-shaped structures, usually tilting westward, and EPB extends to a long distance along the geomagnetic field lines. It is found that the west wall of EPB is relatively stable, while there are some bifurcations on the east wall of EPB, and the bifurcation of EPB becomes more pronounced with time. Moreover, the spatial scale of EPB gradually increases with time, which is about several hundred kilometers, and the drift velocity of EPB is in the range of 40–130 m/s (+/−20 m/s). The statistical results show that EPBs mainly occur in the months of September to November and February to April, with a higher occurrence rate. In terms of seasonal occurrence, EPBs tend to appear more frequently in spring and autumn, and the occurrence rate of EPBs is relatively low in winter and summer. [ABSTRACT FROM AUTHOR]

This study proposes a decomposed broad learning model to improve the forecasting accuracy for tourism arrivals on Hainan Island in China. With decomposed broad learning, we predicted monthly tourist arrivals from 12 countries to Hainan Island. We compared the actual tourist arrivals to Hainan from the US with the predicted tourist arrivals using three models (FEWT-BL: fuzzy entropy empirical wavelet transform-based broad learning; BL: broad Learning; BPNN: back propagation neural network). The results indicated that US foreigners had the most arrivals in 12 countries, and FEWT-BL had the best performance in forecasting tourism arrivals. In conclusion, we establish a unique model for accurate tourism forecasting that can facilitate decision-making in tourism management, especially at turning points in time. [ABSTRACT FROM AUTHOR]

Objective: To analyze the epidemiological characteristics of COVID-19 cases (Omicron variant BA5.1.3 ) in a hotel Fangcang shelter hospital in Sanya, Hainan Province, and provide basis for optimizing epidemic prevention and control strategies. Methods: The epidemiological data of COVID-19 cases admitted to a hotel Fangcang shelter hospital in Sanya from August 10 to August 30 in 2022 were collected for descriptive epidemiological analysis. Results: By August 30, 703 cases of COVID-19 had been treated in the hotel Fangcang shelter hospital. The epidemiological characteristics analysis showed that 328 cases were male, accounting for 46.7%, and 375 cases were female, accounting for 53.3%. The ratio of male to female was 0.87:1. The age range was 8 months to 85 years old, with a median of 37 (20,49) years old. The majority of people aged 31-59 years old, accounting for 51.4%. Asymptomatic infection accounted for 39.8%, and mild infection accounted for 60.2%, the main clinical symptoms were cough 24.8% (105/423), fever 18.7% (79/423). 8.8% of the infected people had a history of chronic basic diseases, and hypertension and diabetes were the most common. There were 416 infected patients discharged from hospital, and the median total hospital stay was 14 (10,15) days. The proportion of people who did not receive COVID-19 vaccine was 10.1%, the proportion of people who completed one, two and three vaccination was 5.0%, 36.3% and 48.6% respectively, and the proportion of people who completed two and three vaccinations among people 60 years old was only 10.1% and 8.8%. Conclusion: This strain was the novel coronavirus variant BA5.1.3, which was reported for the first time in China. It was more infectious and insidious, and generally susceptible to people of all ages. Therefore, it is necessary to strengthen personal prevention and control, and did a good job of external anti input and internal anti diffusion, and strengthen nucleic acid detection to realize timely detection and early treatment, and strengthen COVID-19 vaccination, to improve vaccination rate and reduce infection rate. [ABSTRACT FROM AUTHOR]

Summer upwelling areas may serve as a thermal refuge for coral reefs under climate change, and the environmental adaptation of scleractinian coral to upwelling environments remains to be further understood. In this work, we systematically analyzed how the coral holobionts of Galaxea fascicularis respond to different environments between the Qiongdong upwelling and non‐upwelling regions. The presence of colder and more saline water was found in seasonal upwelling region east of Hainan Island. Compared with the corals in the non‐upwelling environment, the corals from the upwelling environment generally had higher Symbiodiniaceae density, tissue biomass, and protein content. Evident spatial differences existed in Symbiodiniaceae composition among different regions, and the corals in the upwelling region had remarkably higher symbiont diversity. Importantly, the coastal upwelling under anthropogenic influence (i.e., nutrient pollution and coastal development) shaped coral bacterial communities significantly and decreased their diversity. Local adaptations of coral to environmental changes can be inferred from the flexibility and ecological functions of the coral core microbiome. In particular, the coastal upwelling environment led assembly of coral‐associated bacteria more deterministic rather than stochastic. In the upwelling region, microbial co‐occurrences had more positive interactions but the ecological network structure had a lower stability. These findings deepen the understanding of the ecological impact of upwelling on coral adaptation in the Anthropocene. Plain Language Summary: With the progress of global climate change, the frequency and severity of coral bleaching are expected to increase significantly. Fortunately, upwelling exposes corals to cool and nutrient‐rich waters, thereby helping to reduce the thermal impacts of climate change and serving as a potential thermal refuge. We investigated and sampled in coral reefs with different environmental gradients, including upwelling and non‐upwelling in Hainan Island. The Galaxea fascicularis samples from the upwelling region exhibited better coral physiological parameters (higher values of Symbiodiniaceae density, tissue biomass, and protein content). In addition, upwelling changed the diversity and structure of the coral microbiota (microalgal endosymbionts and bacteria) significantly. Coral hosts could act as filters for microorganisms, allowing certain microbial taxa to colonize or persist and selecting the most favorable and beneficial microbiome in a specific environment. Upwelling habitats might promote positive cooperation and simple interaction between bacterial communities associated with the coral host, which is crucial for the acclimatization of the holobiont to quickly respond to environmental changes. This study provides detailed analysis of how coral responds to the summer upwelling environment from a microbial perspective. Key Points: Galaxea fascicularis in upwelling under anthropogenic influence suggested high physiological plasticity and symbiont specificityMicrobiome flexibility facilitated local acclimatization of coral holobiont by readily responding to the upwelling environmentUpwelling promoted bacterial assembly more deterministic, but reduced the complexity and stability of the microbial network [ABSTRACT FROM AUTHOR]

Shortly after the cessation of the Cenozoic seafloor spreading in the South China Sea, a period of basaltic magmatism occurred in the Indochina Peninsula. The various types of xenoliths/xenocrysts present in these igneous rocks can provide information about the lithospheric mantle under the Indochina Peninsula. In this study, we present new ages and in situ major and trace element compositions for the xenoliths and olivine xenocrysts from the Wichian Buri and Mae Tha basalt flows in Thailand. The new ages obtained in this study for the Wichian Buri and Mae Tha basalt flows are 9.24 and 2.35 Ma, respectively. Under Thailand, the lithology of the sub-continental mantle lithosphere (SCLM) could be spinel-lherzolite, with a mantle temperature range of 936°C–1096°C. The mantle source of the Cenozoic basalts from Thailand and its adjacent regions could be affect by recycled oceanic crust and carbonates. The origin of spongy textures in clinopyroxene should be resulted from partial melting induced by decompression. SCLM under Thailand were transformed by peridotite-melt interaction, and basaltic melt trapped the mantle xenocryst and xenolith quickly ascended to the surface. [ABSTRACT FROM AUTHOR]

A courtyard is an essential space for natural lighting and natural convective ventilation of residential buildings in hot-humid climates. This study focuses on the internal courtyard configuration on the thermal performance of long strip houses (LSH) in the hot-climate area of Hainan Island, China. The aim is to identify the best design parameters for the courtyard to improve thermal comfort in modern LSH design. Appropriate strategies, including Mahoney table, field investigation, and CFD simulation, are used to determine thermal performance. As a result, the design guidelines of the courtyard are proposed to optimize the thermal comfort towards energy saving. The study reveals the spatial characteristics and climate regulation of internal courtyards in traditional LSH. In addition, the simulation results show that the enclosure with a shaded cover and a high ratio of H/D is conducive to thermal environment and ventilation, and the section of contracted shape from bottom to top is a preferred option in the internal courtyard configuration. This study should, therefore, be of value in designing practical projects with an interior courtyard for architects. [ABSTRACT FROM AUTHOR]

Hainan COherent scatter Phased Array Radar has recorded four patches of daytime F‐region field‐aligned irregularities on 31 May 2021, and it is the first time to investigate the daytime irregularities by the radar imaging technique. In‐beam radar images are plotted on the curved plane transverse to the geomagnetic field lines. The displayed daytime irregularities present the obliquely elongated band‐like structures and the corresponding scatter regions extend to hundreds of kilometers in range and narrow to a few kilometers in the zonal direction. The diffuse and isolated structures were also observed in the radar images. The radar image sequences indicate that the irregularities were continuous in height as they drifted westward. The daytime irregularities maintained the oblique elongated structures that resemble the morphological features of the nighttime equatorial plasma bubbles. Combined with the in situ satellite measurements, these daytime F‐region irregularities are interpreted to be the remnants of the previous night's bubbles and come from the higher altitudes near the magnetic equator. Key Points: Daytime F‐region irregularities in low latitudes were detected by applying in‐beam radar imaging techniqueRadar images of the daytime irregularities exhibit narrow band‐like structures extending hundreds of kilometers verticallyThe band‐like structures are interpreted as remnants of bubbles developed on previous night [ABSTRACT FROM AUTHOR]

The paper had introduced the operation technical regulations of bitter gourd grafting and seedling cultivation, including all kinds of measures before, during and after grafting, in order to provide technical reference for efficient production of bitter gourd. [ABSTRACT FROM AUTHOR]

[Display omitted] • Triassic medium-grade metamorphism is recognized in Hainan Island, the eastern Paleo-Tethyan tectonic domain. • Amphibolite-facies metamorphism of the Mulantou Metamorphic Complex took place at ca. 250–235 Ma. • Peak metamorphic conditions reached 717–771 °C and 4.4–5.8 kbar, equivalent to a geothermal gradient of approximately 30 °C/km. • Mulantou Triassic amphibolite facies metamorphism resulted from collision between the South China and Indochina blocks after closure of the Paleo-Tethys. The Permian-Triassic tectonic evolution of Southeast Asia has long been a subject of considerable debate. Hainan Island in China is located at the junction of the South China and Indochina blocks adjacent to the Pacific (Philippine) Plate. Studies of metamorphic complexes in Hainan Island may shed lights on the Permian-Triassic tectono-thermal events of the eastern Paleo-Tethys. Among these complexes, the newly recognized Mulantou Metamorphic Complex is sporadically exposed in northeastern Hainan Island provides evidence for above-mentioned issues. In this paper, we present the result of a combined petrological and geochronological study of paragneisses in this complex. The paragneisses consist mainly of biotite, plagioclase, quartz, and rutile/ilmenite, with or without garnet, sillimanite, and muscovite. Textural relationships, mineral compositions, and thermobarometric calculations show that these paragneisses record peak metamorphic P − T conditions of 720–770 ℃ and 4.4–5.8 kbar. Zircon and monazite U − Pb dating by laser ablation–inductively coupled plasma–mass spectrometry indicates that metamorphism occurred at 250–235 Ma. Integrating published geochronological, geochemical, and structural data of Hainan Island and along the Jinshajiang − Ailaoshan − Song Ma suture zone, we infer that the Triassic amphibolite-facies metamorphism of the Mulantou Metamorphic Complex resulted from collision between the South China and Indochina blocks after closure of the Paleo-Tethys. [ABSTRACT FROM AUTHOR]

Together, the Yinggehai and Qiongdongnan basins have received a large amount of terrigenous sediments, but the provenance evolution of Cenozoic sediments in the two basins remains disputable. Combined with previous studies in the Yinggehai and Qiongdongnan basins, the elemental geochemistry of Oligocene to Pliocene sediment samples in the junction area of the two basins were analyzed to explore the tectonic implications, parent rock characteristics, and provenance evolution of the two basins during the Cenozoic. The results reveal that all the sediment samples were derived from continental island arc to passive continental margin settings. The light REE enrichment and stable content of heavy REE with large negative Eu anomalies indicate that they were probably derived from Hainan Island. The reconstructed provenance evolution model showed that the Red River Source (RRS) provided sedimentary materials for the Central Depression of Yinggehai Basin from the Oligocene to the Pliocene, and Hainan Island Source (HIS) was also one of the sources for sediments deposited in the Central Depression of Yinggehai Basin during the Miocene. However, most of the sediments preserved in the Yingdong Slope and Qiongdongnan Basin were derived from the HIS from the Oligocene to the Pliocene, and sediments deposited in the Yingdong Slope were also derived from the RRS during the Miocene. Furthermore, the junction area of the two basins had a mixed source of the RRS and HIS during the Cenozoic. [ABSTRACT FROM AUTHOR]