Chongqing Provinces Research Articles

A Study on the Use of Hedges in English Writing of College Students at Different Levels

This paper explored features of hedges in college students’ English writing at different language levels and their differences from native students’ writing. The 2000 writing texts by students from 3 key universities and 8 ordinary universities in Chongqing and Sichuan Province were offered by China Wordnet Company who initiated English writing campaign in 2016. The result showed that compared with native students, students from key and ordinary universities used more hedges, relied on a narrow range of hedges and offered stronger commitments to statements. Language level did not play a decisive role in these aspects.

Predicting the Potential Distribution of the Endangered Plant Cremastra appendiculata (Orchidaceae) in China under Multiple Climate Change Scenarios

Cremastraappendiculata (Orchidaceae) is a perennial medicinal herb, which is included in the national second-class protected plant catalog in China. Due to the influences of climate change and anthropogenic activities, in conjunction with soaring commercial prices, the wild sources of C.appendiculata have been drastically reduced and are in danger of extinction. Consequently, it is important to predict the distribution of potentially suitable growth/propagation areas for C.appendiculata under the backdrop of climate change for its protection and sustainable use. For this study, an optimized maximum entropy model was employed to analyze the distribution patterns and changes of potentially suitable regions for C.appendiculata during different periods since the Last Glacial Maximum (LGM, 18–24 ka). Based on multiple climate change scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5), the distribution range of C. appendiculata was predicted for the 2050s (average for 2041–2060), 2070s (average for 2061–2080), and 2090s (average for 2081–2100). The results revealed that during the LGM period, the highly suitable growth area for C.appendiculata was 0.28 × 104 km2, which accounted for only 3.26% of the current highly suitable growth area. During the mid-Holocene (MH, 6 ka) period, the area of highly suitable regions increased to 8.38 × 104 km2, which accounted for 99.30% of the present highly suitable growth area. Further, the cumulative existing potentially suitable growth area for C. appendiculata is 213.9 × 104 km2, which accounts for 22.28% of China’s territory. Of these lands, the low, medium, and high suitable areas are 147.76 × 104 km2, 57.71 × 104 km2, and 8.44 × 104 km2, respectively. The highly suitable areas are primarily distributed across Sichuan, Gansu, Shaanxi, Chongqing, Guizhou, Hubei, and Anhui Provinces. Moreover, in the future the potentially suitable growth areas for C. appendiculata will decrease to varying degrees. Further, the results of this study found that the relatively low impact areas for C. appendiculata were mainly distributed across Shaanxi, Sichuan, Chongqing, and Guizhou Provinces. Centroid transfer analysis indicated that the center of potentially suitable growth areas for C.appendiculata shifted to the northwest in SSP2-4.5 and SSP3-7.0, while they initially shifted to the northwest and then to the southeast in SSP1-2.6 and SSP5-8.5.

How can an ecological compensation threshold be determined? A discriminant model integrating the minimum data approach and the most appropriate land use scenarios

Ecological compensation has become very common worldwide due to the imbalance in the development of modern society, economy, and the environment and the increased pressure on ecosystem carrying capacity. Nonetheless, the various approaches for quantifying ecological compensation standards differ significantly. Thus, the process for determining a reasonable ecological compensation threshold is important to understand. To ensure the maximization of ecosystem service supply and economic benefit incentives for farmers, this paper constructs a discriminant model of an ecological compensation threshold based on the minimum data approach and the most appropriate land use scenario to define the ecological compensation threshold of the Sloping Land Conversion Program in the upper Yangtze River basin. The results show that with an increase in the compensation price, the proportion of farmers participating in returning farmland to forests and grassland increases, and water conservation increases. However, the discriminant curve first increases to a certain threshold point and then decreases, after which the ecoefficiency rate obtained from the compensation decreases. The ecological compensation thresholds for Chongqing, Sichuan, Yunnan, Guizhou, Hubei, Qinghai, Gansu, Tibet and Shaanxi provinces are 17.74 yuan/m3, 13.79 yuan/m3, 19.1 yuan/m3, 17.79 yuan/m3, 15.28 yuan/m3, 45.14 yuan/m3, 17.23 yuan/m3, 25.2 yuan/m3 and 22.36 yuan/m3, respectively. This research examines ecological compensation standards in different watersheds throughout the world and discusses the relationship between ecological compensation and water conservation. The discriminant model of the ecological compensation threshold can provide a new reference for the implementation and management of ecological compensation policies.

The Prediction of the Potentially Suitable Distribution Area of Cinnamomum mairei H. Lév in China Based on the MaxEnt Model

Cinnamomum mairei H. Lév is a rare and valuable medicinal and timber species in China. It not only has a narrow distribution, but also has few resources, is an endangered species, and is a nationally protected plant. Climate change impacts the growth and development of plants; therefore, it is of great practical significance to predict the current and future distribution of C. mairei H. Lév in suitable areas of China and to protect these endangered plants. In this study, the MaxEnt model was used to predict the suitable growing areas for C. mairei H. Lév according to six environmental factors (the temperature seasonality, max. temperature in the warmest month, min. temperature in the coldest month, precipitation seasonality, precipitation in the coldest quarter and aspect), and three different climate models (SSP126, SSP245, and SSP585) were simulated for three periods (the 2030s, 2050s, and 2070s). In the present study, the suitable ecological environment for C. mairei H. Lév comprised the following: a min. temperature in the coldest month from −0.63 to 4.36 °C, temperature seasonality from 130.67 to 642.58, a max. temperature in the warmest month from 28.86 to 45.97 °C, and precipitation in the coldest quarter from 40.12 to 101.13 mm. Highly suitable habitats for C. mairei H. Lév are located in the Yunnan Province, Guizhou Province, Sichuan Province, and Chongqing City, China (southwestern part of China), and to a lesser extent in the Xizang Province and Shaanxi Province, China. The moderately suitable habitat district overlaps with the highly suitable habitat district, and a small number of suitable habitats are distributed in Guangxi Province, Hunan Province, Hubei Province, and Henan Province. In the future, the highly suitable areas for C. mairei H. Lév will increase slightly, and the gravity points will shift toward northeast China. Our simulations are helpful for understanding the geoecological characteristics of this species and provide a basis for regional projections of this species under current and future climate change scenarios in China. It is proposed to establish nature reserves for C. mairei H. Lév in the Chongqing, Yunnan, Sichuan and Guizhou provinces of China.

Comparison between optimized MaxEnt and random forest modeling in predicting potential distribution: A case study with Quasipaa boulengeri in China

Random forest (RF) and MaxEnt models are shallow machine learning approaches that perform well in predicting species' potential distributions. RF models can produce robust results with the default automatic configuration in most cases, but it is necessary for MaxEnt to optimize the model settings to improve the performance, and the predictive performance difference between optimized MaxEnt and RF is uncertain. To explore this issue, the potential distribution of the endangered amphibian Quasipaa boulengeri in China was predicted using optimized MaxEnt and RF models. A total of 408 occurrence data were selected, 1000 locations were generated as pseudo-absence data by the geographic distance method, and 10,000 sites were selected as background data by creating a bias file. Partial ROC at different thresholds and success rate curves were used to compare the predictive performances between optimized MaxEnt and RF. Our results showed that the RF and optimized MaxEnt models both had good performance in predicting the potential distribution of Q. boulengeri, with the RF model performing slightly better whether based on partial ROC or success rate curves. Furthermore, the core suitable habitat regions of Q. boulengeri identified by RF and MaxEnt were similar and were all located in the Sichuan, Chongqing, Hubei, Hunan, and Guizhou provinces. However, the RF model produced a habitat suitability map with higher discrimination and greater heterogeneity. Temperature annual range, mean temperature of the driest quarter, and annual precipitation were the vital environmental variables limiting the distribution of Q. boulengeri. The RF model is the stronger machine learner. We believe it may be more applicable in predicting the native potential distributions of species with sufficient occurrence data, given the additional predictive detail, the simplicity of use, the computational time involved, and the operational complexity.

Economic burden of dengue fever in China: A retrospective research study.

BackgroundDengue fever has been a significant public health challenge in China. This will be particularly important in the context of global warming, frequent international travels, and urbanization with increasing city size and population movement. In order to design relevant prevention and control strategies and allocate health resources reasonably, this study evaluated the economic burden of dengue fever in China in 2019.MethodsThe economic burden of dengue fever patients was calculated from both family and the organisation perspectives. A survey was conducted among 1,027 dengue fever patients in Zhejiang, Chongqing, and Yunnan Provinces. Treatment expenses, lost working days, and insurance reimbursement expenses information were collected to estimate the total economic burden of dengue fever patients in 2019. The expenditures related to dengue fever prevention and control from government, Center for Disease Control and Prevention (CDC), communities and subdistrict offices of 30 counties (or districts) in Zhejiang Province and Chongqing City were also collected.ResultsThe direct, indirect and total economic burden for dengue fever patients in 2019 in the three Provinces were about 36,927,380.00 Chinese Yuan (CNY), 10,579,572.00 CNY and 46,805,064.00 CNY, respectively. The costs for prevention and control of dengue fever for the counties (or districts) without cases, counties (or districts) with imported cases, and counties (or districts) with local cases are 205,800.00 CNY, 731,180.00 CNY and 6,934,378.00 CNY, respectively. The total investment of dengue fever prevention and control in the 30 counties in China in 2019 was approximately 3,166,660,240.00 CNY.ConclusionThe economic burden of dengue fever patients is relatively high, and medical insurance coverage should be increased to lighten patients’ direct medical economic burden. At the same time, the results suggests that China should increase funding for primary health service institutions to prevent dengue fever transmission.

Effects of Regional Differences in Shale Floor Interval on the Petrophysical Properties and Shale Gas Prospects of the Overmature Niutitang Shale, Middle-Upper Yangtz Block

The lower Cambrian Niutitang/Qiongzhusi shale gas in the Middle-Upper Yangtz Block had been regarded as a very promising unconventional natural gas resource due to its high total organic carbon, great thickness, and large areal distribution. However, no commercial shale gas fields have yet been reported. From the northwest to the southeast there are considerable differences in the sedimentary environments, lithology, and erosive nature of the underlying interval (the floor interval) of the Niutitang shale. However, systematic research on whether and how these regional differences influence shale petrophysical properties and shale gas preservation in the Niutitang shale is lacking. A comparison of Niutitang shale reservoirs as influenced by different sedimentary and tectonic backgrounds is necessary. Samples were selected from both the overmature Niutitang shales and the floor interval. These samples cover the late Ediacaran and early Cambrian, with sedimentary environments varying from carbonate platform and carbonate platform marginal zone facies to continental shelf/slope. Previously published data on the lower Cambrian samples from Kaiyang (carbonate platform), Youyang (carbonate platform marginal zone) and Cen’gong (continental shelf/slope) sections were integrated and compared. The results indicate that the petrophysical properties of the floor interval can affect not only the preservation conditions (sealing capacity) of the shale gas, but also the petrophysical properties (pore volume, porosity, specific surface area and permeability) and methane content of the Niutitang shale. From the carbonate platform face to the continental shelf/slope the sealing capacity of the floor interval gradually improves because the latter gradually passes from high permeability dolostone (the Dengying Formation) to low permeability dense chert (the Liuchapo Formation). In addition, in contrast with several unconformities that occur in the carbonate platform face in the northern Guizhou depression, no unconformity contact occurs between the Niutitang shale and the floor interval on the continental shelf/slope developed in eastern Chongqing Province and northwestern Hunan Province. Such regional differences in floor interval could lead to significant differences in hydrocarbon expulsion behaviour and the development of organic pores within the Niutitang shale. Therefore, shale gas prospects in the Niutitang shales deposited on the continental shelf/slope should be significantly better than those of shales deposited on the carbonate platform face.

Single Molecule Real-Time Sequencing and Traditional Cultivation Techniques Reveal Complex Community Structures and Regional Variations of Psychrotrophic Bacteria in Raw Milk.

In this study, we investigated the species composition and diversity of psychrotrophic bacteria in raw milk from Heilongjiang, Inner Mongolia, Gansu, Henan, Anhui, Jiangsu, Chongqing, and Hunan provinces in China using traditional cultivation and PacBio Single Molecule Real-Time sequencing methods. The isolated psychrotrophic bacteria were highly diverse, which composed of 21 genera and 59 species. Pseudomonas accounted for 58.9% of the total genera while Stenotrophomonas and Enterococcus were also highly represented (above 5.0%). In particular, P. azotoformans occurred at a level of 16.9% and P. paralactis, P. lactis, E. faecalis, and P. marginalis were present in relatively high proportions (above 4.0%). Regional differences were found significantly among the test regions except samples from Heilongjiang and Inner Mongolia were similar. Additionally, differences were observed between days in Henan, Anhui, and Jiangsu samples. Therefore, control strategies must be implemented on regional and season basis.

Projection of climate change impacts on hydropower in the source region of the Yangtze River based on CMIP6

The source region of the Yangtze River located on the Qinghai-Tibet Plateau is very sensitive to climate change. The impact of climate change on the source region of the Yangtze River has been detected from multi-aspect, but limited research has been conducted on the hydropower impact of important water system, especially for the Yalong River, which is the longest tributary in the upper reaches of the Yangtze River and rich in hydropower reserves with a value of approximately 33.72 million kilowatts. In this study, we performed statistical downscaling of 10 Coupled Model Intercomparison Project Phase 6 (CMIP6) models and used the Bayesian weighted ensemble method to analyze the Yalong River basin. The interdecadal climate characteristics of the region were analyzed and drive the variable infiltration capacity (VIC) hydrological model coupled with reservoir operation module to obtain the spatiotemporal changes in water-energy resources in the future. The results showed the precipitation in the Yalong River basin showed an increasing trend (12.38 mm/10a, 25.65 mm/10a) under the shared socioeconomic pathways 2–4.5(SSP2-4.5) and socioeconomic pathways 5–8.5 (SSP5-8.5) scenarios. Coupled with reservoir operation rules, the excess water during the wet season could be transferred to the dry season. Even so, it was estimated the overall power generation of the basin would be reduced by 4% to 6% compared to the baseline period. This change will largely affect the energy of Chongqing and Sichuan Provinces, which rely heavily on the Yalong River for hydropower generation. Our framework and research results are expected to provide useful information for other river systems in the Qinghai-Tibet Plateau and can be used to re-examine the research results of related river basins.

The past, present and future of the pangolin in Mainland China

Two pangolin species, the Chinese pangolin and the Sunda pangolin, occur in mainland China (MC). The Chinese pangolin was once widely distributed throughout provinces south of the Yangtze River, as well as north of the Yangtze River in southern Sichuan, northeast Chongqing, northwest Hubei, and southwest Henan Provinces. However, the range of the Sunda pangolin is limited to border areas of Yunnan Province. Due to overexploitation and habitat loss, the pangolin population has declined dramatically and it is now widely considered extinct in most areas. At present, although the distribution and population size of the pangolin in MC are unclear, residual populations have been confirmed in Yunnan, Hainan, Guangxi, Guangdong, Hunan, Chongqing, Fujian, Jiangxi, Zhejiang and Anhui provinces. Illegal hunting, habitat loss and fragmentation, small populations, low population densities, and reduced food supply are among the major threats facing pangolins today. The Chinese government has focused strongly on pangolin protection. They have been listed as Category I state-protected animals, and corresponding laws, policies and measures have been introduced to protect them from many threats. Important measures for pangolin conservation in MC include the reduction of public consumption demand, community economic development, public education about conservation and illegal activities, creation or expansion of nature reserves, optimization of road and water conservation facility construction, changes in afforestation methods, a moratorium on commercial breeding programs, proper treatment of confiscated pangolins and derivative products, further species conservation research, and international cooperative conservation efforts. If these conservation actions are implemented, the pangolin population in MC will have a bright future.

Study on the Present Situation of Learning Burnout and Its Influencing Factors on High-school Students with Hearing Impairment

To understand the learning burnout and its influencing factors on high-school students with hearing impairment, 240 students were randomly selected in Sichuan, Guizhou and Chongqing province. The survey found that: (1)The learning burnout of High-school students with hearing impairment is generally at lower-middle level; (2)There are significant differences in the scores of personal isolation and learning burnout among high-school students with hearing impairment in different gender; (3)There are very significant differences in the scores of personal isolation among high-school students with hearing impairment of different household types; (4)There are significant differences in the scores of personal isolation and learning burnout between left-behind high-school students and non- left-behind ones; (5) There are very significant differences in the scores of physical and mental exhaustion, learning burnout among high-school students with hearing impairment in different provinces and cities. There are extremely significant differences in the scores of personal isolation; (6) There are significant differences in the scores of personal isolation among high-school students with hearing impairment of different family monthly income. The personal isolation of high school students with hearing impairment whose household income is less than 1,500 Yuan per month is remarkably higher compared with the high school students with hearing impairment whose household income is more than 3001 Yuan per month; (7)There is no significant difference in learning burnout and its each aspect among high school students with hearing impairment in different grades; (8)In the aspect of low achievement, there is a significant cross-impact between genders and whether or not left-behind children; provinces and family monthly income; in the aspects of personal isolation, there is a significant cross-impact between whether or not only-child and whether or not left-behind children; in the aspect of learning burnout, there is a significant cross-impact between grades and family monthly income.

Environmental Drivers and Spatial Prediction of the Critically Endangered Species Thuja sutchuenensis in Sichuan-Chongqing, China

Identifying the ecological environment suitable for the growth of Thuja sutchuenensis and predicting other potential distribution areas are essential to protect this endangered species. After selecting 24 environmental factors that could affect the distribution of T. sutchuenensis, including climate, topography, soil and Normalized Difference Vegetation Index (NDVI), we adopted the Random Forest-MaxEnt integrated model to analyze our data. Based on the Random Forest study, the contribution of the mean temperature of the warmest quarter, mean temperature of the coldest quarter, annual mean temperature and mean temperature of the driest quarter was large. Based on MaxEnt model prediction outputs, the potential distribution map not only identified areas that originally recorded T. sutchuenensis, such as Xuanhan County, Kai County and Chengkou County, but also identified highly suitable distribution areas where T. sutchuenensis may exist, including Wanyuan County, Sichuan Province, and the junction of Chongqing and Hubei Province. This provides a more explicit geographic range for ex situ conservation and reintroduction of T. sutchuenensis. Our results also indicate that, in addition to climate factors, topography and soil factors are also important environmental factors that affect distribution. This provides a theoretical basis for subsequent laboratory construction to simulate the indoor growth of T. sutchuenensis.

Predicting the Potential Distribution of Perennial Plant Coptis chinensis Franch. in China under Multiple Climate Change Scenarios

Coptis chinensis Franch. (Ranales: Ranunculaceae) is a perennial species with high medicinal value. Predicting the potentially geographical distribution patterns of C. chinensis against the background of climate change can facilitate its protection and sustainable utilization. This study employed the optimized maximum entropy model to predict the distribution patterns and changes in potentially suitable C. chinensis’ regions in China under multiple climate change scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5) across different time periods (1970–2000, 2050s, 2070s, and 2090s). The results revealed that the currently potentially suitable regions of C. chinensis span an area of 120.47 × 104 km2, which accounts for 12.54% of China’s territory. Among these areas, the low, moderate, and highly suitable regions are 80.10 × 104 km2, 37.16 × 104 km2, and 3.21 × 104 km2, respectively. The highly suitable regions are primarily distributed in Chongqing, Guizhou, Zhejiang, Hubei, and Hunan Provinces. Over time, the potentially suitable regions of C. chinensis are predicted to shrink. Furthermore, our study revealed that the relatively low impact areas of C. chinensis were mainly distributed in Yunnan, Guizhou, Hubei, Chongqing, and other Provinces. Centroid transfer analysis indicated that except for SSP1-2.6, the center of the potentially suitable region of C. chinensis showed a trend of gradual transfer to the northwest and high-altitude areas.

Predicting the Potential Distribution of Hylomecon japonica in China under Current and Future Climate Change Based on Maxent Model

Hylomecon japonica is considered a natural medicinal plant with anti-inflammatory, anticancer and antibacterial activity. The assessment of climate change impact on its habitat suitability is important for the wild cultivation and standardized planting of H. japonica. In this study, the maximum entropy model (Maxent) and geographic information system (ArcGIS) were applied to predict the current and future distribution of H. japonica species, and the contributions of variables were evaluated by using the jackknife test. The area under the receiver operating characteristic curve (AUC) value confirmed the accuracy of the model prediction based on 102 occurrence records. The predicted potential distributions of H. japonica were mainly concentrated in Jilin, Liaoning, Shaanxi, Chongqing, Henan, Heilongjiang and other provinces (adaptability index > 0.6). The jackknife experiment showed that the precipitation of driest month (40.5%), mean annual temperature (12.4%), the precipitation of wettest quarter (11.6%) and the subclass of soil (9.7%) were the most important factors affecting the potential distribution of H. japonica. In the future, only under the shared socioeconomic Pathway 245 (SSP 245) scenario model in 2061–2080, the suitable habitat area for H. japonica is expected to show a significant upward trend. The area under other scenarios may not increase or decrease significantly.

Spatial-temporal distribution and evolutionary characteristics of water environment sudden pollution incidents in China from 2006 to 2018

Sudden water pollution incidents (SWPI) are random and harmful, which is a problem that cannot be ignored in ecological environment governance and economic development. Identifying spatial-temporal distribution characteristics of SWPI is essential for the disaster prevention and the early warning of water environment. The Kernel Density (DE) and spatial mean center of SWPI transfer curve were used to explore the characteristics with the dataset of 1174 cases from 2006 to 2018 in China. Results showed that: (1) From the time point of view, there was an overall upward trend in the overall number of SWPI. (2) At a regional scale, Eastern China, Southwest China, and Southern China underwent a high frequency with 69.93% of SWPI. The Fujian, Guangdong and Chongqing provinces were specified as the top 3 provinces with incident frequencies. The Yangtze River Basin and the Pearl River Basin were two regions where water pollution incidents occur more often, more than 50% of incidents among basins in China every year. (3) In general, SWPI presents a northeast-southwest distribution pattern and center of SWPI moves in the direction of west by south. (4) More than half of the incidents (57.24% of the total) were induced by illegal pollutant discharge and production safety accidents.

Increased symptoms of post-traumatic stress in school students soon after the start of the COVID-19 outbreak in China

BackgroundThe outbreak of Coronavirus Disease 2019(COVID-19) caused psychological stress in Chinese adults population. But we are unaware of whether the pandemic causes psychological stress on children.MethodsWe used the Children’s Impact of Event Scale questionnaire (CRIES-13) to investigate the degree of Post-traumatic Stress (PTSD) symptoms caused by the pandemic in students selected from schools in Sichuan, Jiangsu, Henan, Yunnan, and Chongqing provinces of China.ResultsA total of 7769 students(3692 male and 4077 female), aged 8–18 years, were enrolled in the study, comprising 1214 in primary schools, 2799 in junior high schools and 3756 in senior high schools. A total of 1639 students (21.1%) had severe psychological stress reactions. A large proportion of senior high school students (23.3%) experienced severe psychological stress, and they had the highest median total CRIES-13 score. Female students were more likely to experience severe psychological stress and had higher median CRIES-13 total scores than males.ConclusionCOVID-19 has placed psychological stresses on primary and secondary school students in China. These stresses are more likely to reach severe levels among female students and senior high school students.

Description of Sinometrius/ donggongensis/ sp. n. (Coleoptera, Carabidae, Paussinae) from the Donggong Mountains, East China.

Wrase and Schmidt (2006) established the genus Sinometrius Wrase Schmidt, 2006 to include the new species S. turnai Wrase Schmidt, 2006 from Hubei province, central China. They placed the new genus in the Paussine tribe Metriini, and compared it to the Nearctic genus Metrius Eschscholtz, 1829. Deuve (2020) described a second species S. jaroslavi Deuve, 2020 from Chongqing province.

First report of Fusarium solani Species Complex Causing Root Rot of Loquat (Eriobotrya japonica) in China.

Loquat (Eriobotrya japonica), a native fruit tree to China, is a popular edible fruit with medicinal properties (Badenes et al. 2013). A 2016-2019 field survey of ~13,000 loquat trees in two orchards in Chongqing and Fujian provinces showed about 5 to 10% root rot disease incidence. The disease symptoms included leaf yellowing, wilting, rotting of main root, and cracking of lateral roots, eventually leading to defoliation and death. To determine the causative agent, diseased roots from six trees were collected, washed in tap water, cut into 2-3 mm pieces, and disinfected for 3 min in 75% (v/v) EtOH. After rinsing in sterilized water, the root pieces were soaked in 10% NaClO (w/v) for 5-10 min, rinsed thrice in sterile water, and plated on potato dextrose agar (PDA). After 7 days of incubation at 25°C, individual spores were collected from the fungal colonies and replated. Single spore cultures growing on PDA gave rise to woolly-cottony, cream-white colored aerial mycelium and a yellowish pigmented mycelium. The average colony growth rate was 8.6 mm day-1 (n=3). Microscopic observation of the mycelium revealed septate and hyaline hyphae and long cylindrical monophialides. Macroconidia were moderately curved, stout, 3-4 septate, measuring 20.79-48.70 μm × 4.16-10.14 μm (n=50). Microconidia produced from long phialides were kidney-shaped, 0-2 septate, and 5.72-17.28 μm × 2.29-6.51 μm (n=50) in size. The mycelial characteristics and reproductive structures of the isolates fit the morphological description of Fusarium sp. (Summerell et al. 2003). To confirm this identification, translation elongation factor (EF-1α) and RNA polymerase I beta subunit (RPB1) and RNA polymerase II beta subunit (RPB2) regions of the genome were PCR amplified from 3 separate isolates (R2, R4 and R5) using EF1/ EF2, RPB1-Fa/G2R, RPB2-5f2/7cR & RPB2-7cF/11aR primer pairs (O'Donnell et al. 2010) and sequenced. BLASTn comparison of the EF-1α (MT976167), RPB1 (MT967271) and RPB2 (MW233052) regions from isolate R4 showed 99% identity with the EF-1α (GU170620, 675/676 bp), RPB1 (KC808270, 1543/1545 bp) and RPB2 (MK4419902, 1637/1638 bp) sequences of Fusarium solani species complex (FSSC) in GenBank database. The same species level identification was also found using FUSARIUM-ID and FUSARIUM-MLDT databases. Two-year-old seedlings (n=3) of two different cultivars, 'Hunanzaoshu' and 'Huabai No. 1', growing in pots indoors at 25-27 °C were inoculated by drenching the soil with a conidial suspension of isolate R4 (40 mL, 106 conidia mL-1 obtained from 6-10 day old cultures). Control plants (n=3) were inoculated with sterilized water. At 20 days after inoculation (DAI) the leaves of inoculated plants became chlorotic and wilted, defoliated over time, and by 53 DAI 91.67% of plants died. The taproot and lateral roots of inoculated plants appeared brown to black in color and most lateral roots died and decomposed at 53 DAI, whereas the control plant roots remained healthy. All control plants remained symptomless. Based on morphological and molecular characters (TEF-1, RPB1 and RPB2), the re-isolated pathogen from diseased plants was identical to the R4 isolate used for inoculation and the disease assays were repeated thrice. FSSC was recently reported to cause fruit rot disease on loquat in Pakistan (Abbas et al. 2017). Identifying Fusarium solani species complex as a disease agent in Chinese loquat will assist in future development of improved germplasm for this important worldwide tree crop.

Detection of Novel Spotted Fever Group Rickettsiae (Rickettsiales: Rickettsiaceae) in Ticks (Acari: Ixodidae) in Southwestern China.

Spotted fever group rickettsiae, mainly maintained and transmitted by ticks, are important etiological agents of (re)emerging zoonotic diseases worldwide. It is of great significance to investigate spotted fever group rickettsiae in ticks in different areas for the prevention and control of rickettsioses. In this study, a total of 305 ticks were collected from wild and domestic animals in Chongqing, Guizhou, Yunnan, and Guangxi provinces of southwestern China during 2017-2019 and examined for the presence of spotted fever group rickettsiae by PCR with primers targeting the partial gltA, ompA, rrs, and htrA genes. Results showed that two spotted fever group rickettsiae species, including the pathogenic Candidatus Rickettsia jingxinensis (Rickettsiales: Rickettsiaceae) and a potential novel species Rickettsia sp. sw (Rickettsiales: Rickettsiaceae), were identified. The Ca. R. jingxinensis sequences were recovered from Rhipicephalus microplus (Ixodida: Ixodidae) and Haemaphysalis longicornis (Ixodida: Ixodidae) ticks and phylogenetically clustered with previous Ca. R. jingxinensis, Ca. R. longicornii (Rickettsiales: Rickettsiaceae), and Rickettsia sp. XY118 (Rickettsiales: Rickettsiaceae) strains. Rickettsia sp. sw was detected in Amblyomma geoemydae (Ixodida: Ixodidae) and Rh. microplus. Interestingly, as far as we know, this was the first report of Rickettsia (Rickettsiales: Rickettsiaceae) in A. geoemydae. Phylogenetic analyses indicated that this potential novel species was closely related to R. aeschlimannii (Rickettsiales: Rickettsiaceae) with gltA and ompA genes and grouped in a cluster composed of R. montanensis (Rickettsiales: Rickettsiaceae), R. raoultii (Rickettsiales: Rickettsiaceae), R. aeschlimannii, R. massiliae (Rickettsiales: Rickettsiaceae), and R. rhipicephali (Rickettsiales: Rickettsiaceae) with htrA, while formed a separate clade with rrs. The pathogenicity of Rickettsia sp. sw should be further confirmed. These results expand the knowledge of the geographical distribution and vector distribution of spotted fever group rickettsiae in China and are useful for assessing the potential public health risk.

Study on the Preferential Flow Characteristics under Different Precipitation Amounts in Simian Mountain Grassland of China

Understanding the response of preferential flow paths to water movement is an important topic in soil hydrology. However, quantification of the complicated distribution patterns of preferential flow paths remains poorly understood. Therefore, dye experiments were conducted to investigate preferential flow characteristics under three different precipitation amounts (20, 40 and 60 mm, numbered as the G20, G40 and G60, respectively) in Simian Mountain grassland, Chongqing province, China. O-ring statistics were used to analyze the spatial distribution characteristics and the spatial correlation of preferential flow paths. Results revealed that precipitation could promote dye tracer infiltration into deeper soils, reaching the maximum depth of 55 cm in G60. The number of preferential flow paths in G60 plots was 3.0 and 7.4 times greater than those of G40 and G20, respectively. Structural distribution of the preferential flow paths showed a gradually clumped pattern with the increase of precipitation, which was conducive to enhancing the correlation between preferential flow paths in each pore size range. These results could expand our understanding of the effects of precipitation on the characteristic of preferential flow paths in grassland, which is helpful to evaluate the water movement in the study area.