Sichuan Region Research Articles

Impact of land expropriation on farmers’ livelihoods in the mountainous and hilly regions of Sichuan, China

Research on the sustainable livelihoods of rural households is of great significance to mitigating rural poverty and reasonable land expropriation policy helps to realize better livelihoods and sustainable development. Scholars have conducted considerable research on the relationships between land expropriation and farmers' livelihoods. However, few quantitative studies have used the characteristics of villages as control variables to systematically analyze the impact of land expropriation on farmers' livelihood capital and strategy in the mountainous and hilly regions of China. This study uses the Partial Least Squares-Structural Equation Model (PLS- SEM) to systematically explain the impact of land expropriation on farmers' livelihoods in mountainous and hilly regions of Sichuan in 2013, with the characteristics of the village including income, accessibility and terrain as control variables. The analysis uses both representative sample data of 240 rural households and spatial data calculated using a 30 m Digital Elevation Model (DEM) by Geographic Information System (GIS). Results are as follows: (1) The land expropriation characteristics are negatively affected by village accessibility. Villages with worse accessibility tend to have fewer land parcels and less land area expropriated. Additionally, land that is expropriated from inaccessible villages tends to receive less compensation. (2) Natural capital is negatively affected by number and area of land expropriation. Natural capital is not only directly affected by village accessibility, but also indirectly affected by village accessibility through the mediating effect of the number and area of land parcels expropriated. (3) Physical capital is positively affected by compensation for land expropriation, and negatively affected by village accessibility through compensation for land expropriation. The worse a village's accessibility/location is, the less compensation it will receive for land expropriation, resulting in lower physical capital. (4) Financial capital is negatively affected by village accessibility indirectly through compensation for land expropriation. The better the village's accessibility is, the greater is its compensation for land expropriation and, hence, the greater is its financial capital. (5) Social capital is directly and negatively affected by the number and area of land parcels expropriated, and is indirectly and positively affected by village accessibility through the number and area of land parcels expropriated. This study enhances our understanding of the characteristics of land expropriation and rural households' livelihood as well as the impact of land expropriation on rural households' livelihood. These findings provide reference for the formulation of proper policies related to land expropriation and the improvement of rural households' livelihoods in the mountainous and hilly regions of China.

Preliminary seismic vulnerability matrix related with fortification intensity for Sichuan region

The significance to develop fortification intensity related vulnerability matrix for earthquake prevention and mitigation is emphasized in this paper. The way to acquire the fortification intensity data of buildings damaged in the great Wenchuan earthquake, from their construction years with the seismic zoning maps in three time periods, is reported. Preliminary statistical results of vulnerability matrices related with fortification intensity VI, VII and VIII, are presented for brick-concrete structure and frame structure buildings in Sichuan region. The results show clearly the decrease of vulnerability with increase of the fortification level.

GIS-based earthquake-triggered-landslide susceptibility mapping with an integrated weighted index model in Jiuzhaigou region of Sichuan Province, China

Abstract. A Mw=6.5 earthquake struck the Jiuzhaigou region of Sichuan Province, China, at 21:19 LT on Tuesday, 8 August 2017, and triggered a large number of landslides. For mitigating the damages of earthquake-triggered landslides to individuals and infrastructures of the earthquake-affected region, a comprehensive landslide susceptibility mapping was attempted with an integrated weighted index model by combining the frequency ratio and the analytical hierarchy process approaches under a GIS-based environment in the heavily earthquake-affected Zhangzha town of the Jiuzhaigou region. For this purpose, a total number of 842 earthquake-triggered landslides were visually interpreted and located from Sentinel-2A images acquired before and after the earthquake at first, and then the recognized landslides were randomly split into two groups to establish the earthquake-triggered landslide inventory, among which 80 % of the landslides were used for training the integrated model and the remaining 20 % for validation. Nine landslide controlling factors were considered including slope, aspect, elevation, lithology, distance from faults, distance from rivers, land use–land cover, normalized difference vegetation index and peak ground acceleration. The frequency ratio was utilized to evaluate the contribution of each landslide controlling factor to landslide occurrence, and the analytical hierarchy process was used to analyse the mutual relationship between landslide controlling factors. Finally, the landslide susceptibility map was produced by using weighted overlay analysis. Furthermore, an area under the curve approach was adopted to comprehensively evaluate the performance of the integrated weighted index model, including the degree of model fit and model predictive capability. The results demonstrated the reliability and feasibility of the integrated weighted index model in earthquake-triggered landslide susceptibility mapping at a regional scale. The generated map can help engineers and decision makers assess and mitigate hazards of the earthquake-triggered landslides to individuals and infrastructures of the earthquake-affected region.

Isolation and identification of the spoilage microorganisms in Sichuan homemade Paocai and their impact on quality and safety.

The spoilage microbiology in Paocai (fermented vegetables) affects not only the quality of this popular traditional Chinese food but also its safety. This study aimed to isolate and identify the microorganisms commonly leading to spoilage in homemade Paocai from the Sichuan region and, further, to scientifically assess the impact of these microorganisms on product quality and safety. Seven putrid Paocai samples were collected from 7 families in different Sichuan cities. From these, 45 strains were isolated by means of a nutrient agar medium and rose bengal agar. All of the 22 strains (5 fungi and 17 bacteria) with different colonial morphologies and corruption phenomenon in Paocai were determined 16S rDNA/18S rDNA gene sequences. Bacteria were identified as Bacillus spp. (16 strains) and Staphylococcus saprophyticus (1 strain), while the 5 fungi were identified as Candida spp. (3 strains), Kodamaea ohmeri (1 strain), and Geotrichum candidum (1 strain). Based on the results of identification, 7 representative strains of different species were determined as the spoilage characteristics in paocai. All the representative strains metabolized to produce nitrite. Strain SPF21 (K. ohmeri) has a particularly serious impact on the crunchiness of Paocai; however, strains SPF19 (Bacillus subtilis) and SPF21 have the greatest influence on its color. All five of the fungi were seen to form a film on the surface of the Paocai, with SPF5 (G. candidum) exerting the most extreme influence. The growth characteristics in the broth showed that all the representative strains investigated metabolized most of the carbohydrates and were able to tolerate the salinity and acidity of the ordinary homemade Paocai. Moreover, these strains were found to have obvious impacts on the volatile components of Paocai, especially SPF2 and SPF8, with higher dimethyl disulfide and dimethyl trisulfide, which were found to have a pungent odor when highly concentrated.

Study on the Temporal and Spatial Pattern Differences of Chinese Light Curl Based on DMSP/OLS

Nighttime light data can detect surface gleams that can intuitively reflect human socioeconomic activity. This paper uses the DMSP/OLS nighttime lighting data from 2001 to 2007 to analyze the coupling relationship between regional economic development and nighttime light intensity in China using regression model. The results show that the brightest areas of nighttime light are mainly concentrated in the Beijing-Tianjin-Hebei region, the Yangtze River Delta region, and the Pearl River Delta region. With the change of the year, the brightness of the three regions is brighter year by year, indicating that the economy is more and more developed. The linear regression model of total brightness and GDP of regional light: Y=792.218+0.024X, linear slope is 0.024, indicating a positive correlation trend. The provinces and cities with the highest total brightness of the provinces and cities are Guangdong Province, Shandong Province, and Jiangsu Province, and the lowest provinces and cities are Qinghai Province and Tibet Autonomous Region. The total brightness of regional lights in China’s provinces and cities is well coupled with GDP. The total brightness of regional lights in all provinces and cities is weakened from east to west. The brightness of the 11 provinces in the eastern region is the strongest, including Beijing, Tianjin, Hebei, Liaoning, Shanghai, and Jiangsu, Zhejiang, Fujian, Shandong, Guangdong, Hainan Province. The second most powerful lighting is the eight provinces in the central region including Shanxi, Jilin, Heilongjiang, Anhui, Jiangxi, Henan, Hubei, and Hunan. The weakest lighting is in the western regions of Sichuan, Chongqing, Guizhou, Yunnan, Tibet, Shaanxi, Gansu, Qinghai, Ningxia, Xinjiang, Guangxi, Inner Mongolia and other provinces (cities). In the east of the Hu Huanyong line, the nighttime lighting is higher than the west of the Hu Huanyong line. The eastern part of China’s seven geographical divisions (Shanghai, Jiangsu, Zhejiang, Anhui, Jiangxi, Shandong, Fujian, and Taiwan) has the brightest night lights. The northwestern region (Shaanxi, Gansu, Qinghai, Ningxia Hui Autonomous Region, Xinjiang Uygur Autonomous Region, and Inner Mongolia Autonomous Region) has a weak night light. The brightness information of nighttime remote sensing data selected in this study can reflect the level of regional economic development.

Comparison of Taiji and aerobic exercise for functional constipation: study protocol for a randomised controlled neuroimaging trial

IntroductionTaiji has been proven to be effective for regulating both the physical and mental state compared with simple aerobic exercise. However, whether the improvement of Taiji for constipation is related...

Assessment of ECMWF reanalysis data in complex terrain: Can the CERA‐20C and ERA‐Interim data sets replicate the variation in surface air temperatures over Sichuan, China?

AbstractSurface air temperatures (SATs) derived from the European Centre for Medium‐Range Weather Forecasts (ECMWF) ERA‐Interim and CERA‐20C reanalysis data sets are compared with data from 43 observation stations in Sichuan for 1979–2010. The results show (a) the temperatures from the ERA‐Interim and CERA‐20C data sets are strongly correlated with those from the observation stations, although significant cold biases are seen on both annual and seasonal timescales. (b) The biases in SATs are predominately influenced by the differences between the actual topography and the topography used in the reanalysis models. Larger differences in temperature are observed in the plateau and mountainous regions of Sichuan. We confirmed larger SAT biases at high altitudes by categorizing the elevation into four bands, each with a spacing of 1,000 m. (c) We reduced the biases resulting from elevation by using an elevation correction method with internal lapse rates derived from different reanalysis pressure levels. The annual mean bias was reduced from −2.86 to −0.75°C for the ERA‐Interim data set and from −5.27 to −2.21°C for the CERA‐20C data set. After calibration, the correlation coefficients between the difference in SAT (observed minus reanalysis data) and the difference in elevation (station elevation minus model elevation) decreased from −0.97 and −0.91 to −0.29 and −0.30 for the ERA‐Interim and CERA‐20C data sets, respectively. These significant differences should not be ignored in the application of reanalysis data sets to climate research. The evaluation and calibration of reanalysis data sets are essential before making assessments of regional climate change, especially over regions with complex topography.

The Effect of the Grain for Green Program on Ecosystem Health in the Upper Reaches of the Yangtze River Basin: A Case Study of Eastern Sichuan, China.

The Eastern Sichuan Region (ESR) is one of the key pilot regions for Grain for Green Program (GGP) implementation in the upper reaches of the Yangtze River basin in China. Therefore, monitoring the effect of the GGP on the ecosystem in the ESR is important. In this study, the Mann–Kendall Trend Test Model was used to ascertain the changes in vegetation coverage. The transfer matrix was used to explore the changes in Land Use/Land Cover (LULC). LULC change direction model (LCDM) was used to preliminarily assess the impact of LULC changes on the ecosystem. The Pressure–State–Response model (PSR), reflecting the human pressure and the ecosystem state, was applied to analyze the spatial–temporal characteristics of the ecosystem health index (EHI). The time span of this study was from 1990 to 2015. The results show that the vegetation coverage changed significantly (p < 0.05), and ecosystem function developed towards positive because of the increase in the coverage of forestland and water land and decrease in the coverage of farmland. The spatial distribution of the EHI was influenced by the pattern of land use. The eastern region, associated with a large area of forestland and grassland, has a low population density and a low degree of land use exploitation, resulting in a high EHI value. The situation was completely opposite in the western region. Regarding the temporal scale, in spite of the decreasing pressure indicator, most counties had experienced an increase in the EHI. There was a clear correlation between the increased EHI values and the restored areas at the third stage (2000–2005) (p < 0.05, r2 = 0.164), but this correlation disappeared at the latter stage (2005–2015) (p > 0.05). The changes showed significant variations in time and area because of differences in the process and the intensity of the implication of the GGP.

Revision of the flightless click-beetle genus Neodima Schimmel amp; Platia br />(Elateridae: Dimini) endemic to China, with comments on its systematic position.

Distribution of flightless insect lineages often help us to identify the areas of long-term stability which serve as biodiversity hotspots. In this paper we taxonomically revise the wingless click-beetle genus Neodima Schimmel Platia, 1992 endemic to the mountainous regions of Sichuan, China. Neodima sichuanensis Schimmel Platia, 1992 and N. cechovskyi Schimmel, 1998 are redescribed, and N. belousovi Prosvirov Kundrata sp. nov. is described as new for science. The distribution and morphological diversity of Neodima is discussed, main diagnostic characters for all species are figured, and an identification key to the species of this genus is provided. Mouthparts as well as female pregenital segments and genitalia are described and figured for the first time for this genus. Further, we compare Neodima to morphologically similar genera, and discuss its systematic position within Dimini.

Research and study on village landscape genetic characteristics in minority area-with Tibet and Qiang watchtower village in west Sichuan region as an example

Cultural landscape is adopted as the main line, and Tibet and Qiang watchtower village in west Sichuan region is adopted as the research object in the paper. The environment, architecture, settlement culture characteristics and their relationships in Tibet and Qiang watchtower village are analyzed by literature, field survey and other methods based on the landscape gene theory. The implied landscape gene is recognized and extracted, thereby revealing the rules of watchtower village settlements in site selection, zoning, spatial pattern and other aspects. A general recognition system is formed. It is expected to provide some theories and methods for genetic archetype mining and gene protection of minority area traditional settlements.

Latent Infection of Powdery Mildew on Volunteer Wheat in Sichuan Province, China.

Wheat powdery mildew, caused by the fungal pathogen Blumeria graminis f. sp. tritici, is one of the most destructive wheat diseases in China, especially in Sichuan Province. Successfully oversummered B. graminis f. sp. tritici can become a primary infection source for wheat seedlings in the fall. Determining the latent infection level of B. graminis f. sp. tritici in volunteer wheat and the oversummering areas of B. graminis f. sp. tritici is important for estimating potential B. graminis f. sp. tritici epidemics. In this study, we clarified the critical role of volunteer wheat in the B. graminis f. sp. tritici oversummering cycle and determined whether latent B. graminis f. sp. tritici infection was present in volunteer wheat by using real-time polymerase chain reaction (real-time PCR). The results indicated that volunteer wheat was mostly found in the northeast and middle regions of Sichuan, where lower temperatures and higher precipitation are common. A total of 13.2% of samples showed symptoms of B. graminis f. sp. tritici (spores) in the field, and 36.8% of samples were found to carry the B. graminis f. sp. tritici pathogen, even though no symptoms were observed. Volunteer wheat with B. graminis f. sp. tritici infection symptoms was found at an altitude of 536 m but volunteer wheat latently infected by B. graminis f. sp. tritici was identified at the lowest altitude of 323 m. Crop shade (e.g., corn and lima bean) provided suitable conditions for the survival of volunteer wheat in the summer. In addition, volunteer wheat played a key role in the B. graminis f. sp. tritici oversummering cycle. Moreover, B. graminis f. sp. tritici could oversummer by infecting generations of volunteer wheat in the summer, thereby becoming the primary infection source for autumn-sown wheat. The results showed that the latent infection of wheat diseases could be rapidly quantified by real-time PCR. Here, the primary disease center of autumn-sown wheat in Ya'an and Wenjiang were detected accurately based on this method. This study provides solid evidence for identifying the disease center, which offers guidance for wheat disease control and management.

Structural geology and favorable exploration prospect belts in northwestern Sichuan Basin, SW China

The northwestern Sichuan region has experienced multi-stage tectonic evolution including marine cratonic basin from the Sinian to the Middle Triassic and intra-continental basin from the Late Triassic to the Cenozoic. Several regional tectonic activities caused complicated stratigraphic distribution and structural deformations in the deep-buried layers. During the key tectonic periods, some characteristic sedimentary and deformation structures were formed, including the step-shaped marginal carbonate platform of Dengying Formation, the western paleo-high at the end of Silurian, and the passive continental margin of the Late Paleozoic–Middle Triassic. The Meso-Cenozoic intra-continental compressional tectonic processes since the Late Triassic controlled the formation of complex thrusting structures surrounding and inside the northwestern basin. The northern Longmenshan fold-thrust belt has a footwall in-situ thrust structure, which is controlled by two sets of detachments in the Lower Triassic and Lower Cambrian and presents as a multi-level deformation structure with the shallow folds, the middle thin-skin thrusts and the deeper basement-involved folds. The thrust belt in front of the Micangshan Mountain shows a double-layer deformation controlled by the Lower Triassic salt detachment, which is composed by the upper monocline and deep-buried imbricate thrust structures. The interior of the basin is characterized by several rows of large-scale basement-involved folds with NEE strike direction. From the perspective of structural geology, the favorable exploration reservoirs and belts in northwestern Sichuan have obvious zoning characteristics. The favorable exploration layers of Dengying Formation of Upper Sinian are mainly distributed in the eastern and northern areas of the northwestern Sichuan Basin, in which the Jiulongshan structural belt, Zitong syncline and Yanting slope are the most favorable. The Lower Paleozoic was transformed by Caledonian paleo-uplift and late Cenozoic folding, and the midwest area such as the Zitong syncline is a potential area for hydrocarbon exploration. The favorable part of the Upper Paleozoic is mainly distributed in the northern Longmenshan belt and its frontal area, where the deep-buried thin-skin thrust structures in the footwall are the key exploration targets.

A statistical analysis of TIR anomalies extracted by RSTs in relation to an earthquake in the Sichuan area using MODIS LST data

Abstract. Research in the field of earthquake prediction has a long history, but the inadequacies of traditional approaches to the study of seismic threats have become increasingly evident. Remote sensing and Earth observation technology, an emerging method that can rapidly capture information concerning anomalies associated with seismic activity across a wide geographic area, has for some time been believed to be the key to overcoming the bottleneck in earthquake prediction studies. However, a multi-parametric method appears to be the most promising approach for increasing the reliability and precision of short-term seismic hazard forecasting, and thermal infrared (TIR) anomalies are important earthquake precursors. While several studies have investigated the correlation among TIR anomalies identified by the robust satellite techniques (RSTs) methodology and single earthquakes, few studies have extracted TIR anomalies over a long period within a large study area. Moreover, statistical analyses are required to determine whether TIR anomalies are precursors to earthquakes. In this paper, RST data analysis and the Robust Estimator of TIR Anomalies (RETIRA) index were used to extract the TIR anomalies from 2002 to 2018 in the Sichuan region using Moderate Resolution Imaging Spectroradiometer (MODIS) land surface temperature (LST) data, while the earthquake catalog was used to ascertain the correlation between TIR anomalies and earthquake occurrences. Most TIR anomalies corresponded to earthquakes, and statistical methods were used to verify the correlation between the extracted TIR anomalies and earthquakes. This is the first time that the ability to predict earthquakes has been evaluated based on the positive predictive value (PPV), false discovery rate (FDR), true-positive rate (TPR), and false-negative rate (FNR). The statistical results indicate that the prediction potential of RSTs with use of MODIS is limited with regard to the Sichuan region.

Phenotypic and Genetic Characterization of Botrytis cinerea Population from Kiwifruit in Sichuan Province, China.

Botrytis cinerea (anamorph of Botryotinia fuckeliana) causes gray mold on numerous plants, including kiwifruit. The primary aim of this study was to investigate the phenotypic and genetic characteristics of the Botrytis cinerea population from kiwifruit in Sichuan Province, China. In all, 176 isolates were collected from kiwifruit orchards from eight geographic regions in Sichuan. All isolates were identified as B. cinerea sensu stricto based on the combined datasets, including morphological criteria, determination of the Bc-hch allele, and phylogenetic analysis of the genes RPB2, G3PDH, and HSP60. Three colony types (i.e., sclerotial, mycelial, and conidial) were observed on potato dextrose agar after 2 weeks, with sclerotial isolates, the predominant category, accounting for 40.91%. No obvious differences in microscopic characteristics were observed among the three types. Three genotypes of transposable elements were identified in the B. cinerea population: boty, flipper, and transposa types. The most prevalent genotype from different geographic populations of B. cinerea was transposa; in contrast, the flipper genotype accounted for only 3.98% of the total population, whereas the vacuma genotype was absent. According to MAT locus amplification, 87 and 89 isolates are MAT1-1 and MAT1-2 type, respectively, and the two mating types were found to be balanced overall in the population. Forty-eight representative isolates were all able to cause gray mold to some extent, and disease severities were significantly different between the cultivars Hongyang and Hort16A (P < 0.01). Disease severity was significantly greater on young leaves than on mature leaves (P < 0.01). No significant relationship was found between pathogenicity and geographical region, colony type, or transposon distribution. The results obtained in the present study suggest a relatively uniform species diversity of Botrytis but rich phenotypic and genetic differentiation within the B. cinerea population on kiwifruit in China. Utilizing resistant cultivars and rain-shelter cultivation instead of fungicides may be an effective approach to delaying pathogen variability.

Interactions between sustainable livelihood of rural household and agricultural land transfer in the mountainous and hilly regions of Sichuan, China

AbstractResearch on the sustainable livelihoods of rural households is of great significance in solving rural poverty and promoting the transfer of rural land management rights, which are necessary for realizing better livelihoods and sustainable development. In this study, we used a partial least squares‐structural equation model to systematically explain the interacting mechanisms of livelihood capital, livelihood strategy, and agricultural land transfer in the mountainous and hilly regions of Sichuan, China, based on survey data from 240 rural households. The results are as follows: (a) land transfer characteristics were negatively affected by farmers' livelihood strategies. The higher the proportion of the nonagricultural labor force/livelihood diversity index, the greater the possibility to roll‐out plots. The lower the proportion of the nonagricultural labor force/livelihood diversity index, the greater the possibility to roll‐in plots. (b) Natural capital was directly and negatively affected by livelihood strategy, and indirectly and positively affected by land transfer. (c) Financial capital insurance was indirectly and positively affected by livelihood strategy. Financial capital insurance had a mediating effect: land transfer not only had a direct negative effect on it but also had an indirect effect through natural capital. (d) Financial capital income was directly positively affected by financial capital insurance, and indirectly negatively affected by land transfer and natural capital. Financial capital income had a mediating effect, and livelihood strategy not only had a direct positive effect on it but also had an indirect positive effect via human capital. (e) Physical capital and human capital were directly positively affected by livelihood strategy. (f) Certain moderating effects were observed. Nonagriculture‐dependent farmers had higher physical capital, greater human capital, higher financial capital income, and more area of roll‐out plots than agriculture‐dependent farmers. This study provides theoretical guidance for the formulation of policies for livelihood improvement and sustainable development.

Effects of bistrifluron resistance on the biological traits of Spodoptera litura (Fab.) (Noctuidae: Lepidoptera).

Spodoptera litura is one of the major insect pests of vegetables in Sichuan, China, and it has developed serious resistance to many traditional chemical insecticides. In this present study, S. litura individuals collected from five regions in Sichuan in 2017, which were detected the resistance to bistrifluron. We found that the resistance ratios (RRs) bistrifluron were in the ranges of 15.9- to 77.7-fold, respectively, compared with a laboratory susceptible (Lab-HN) strain. To elucidate the effect of bistrifluron on the life history parameters of S. litura, we established the bistrifluron-susceptible (Bis-UNSEL) and bistrifluron-resistant (Bis-SEL) strains based on the DY field population with the highest RR of 77.7-fold among the all field populations to bistrifluron compared with a laboratory Lab-HN strain. The results show that the Bis-SEL strain developed a 113.8-fold RR while that of the Bis-UNSEL strain was almost equal to that of the Lab-HN strain (with overlapping confidence intervals (CI) of their LC50 values, P < 0.05). Meanwhile, the life span of the egg and pupa stage of the Bis-UNSEL strain was prolonged, and the strain also showed shorter adult duration and lower fecundity. Demographic characteristics, such as the intrinsic rate of increase (r), finite rate of increase (λ) and net reproductive rate (R0) in the Bis-SEL strain were significantly higher than the Bis-UNSEL strain, whereas the mean generation time (T) and gross reproduction rate (GRR) were lower. The results clearly showed that the developing resistance of bistriflueon on S. litura promoted its population growth. Therefore, the present study could provide useful informations for determining potential management methods to prevent the development of bistrifluron resistance in S. litura.

Spatiotemporal Changes and the Driving Forces of Sloping Farmland Areas in the Sichuan Region

Sloping farmland is an essential type of the farmland resource in China. In the Sichuan province, livelihood security and social development are particularly sensitive to changes in the sloping farmland, due to the region’s large portion of hilly territory and its over-dense population. In this study, we focused on spatiotemporal change of the sloping farmland and its driving forces in the Sichuan province. Sloping farmland areas were extracted from geographic data from digital elevation model (DEM) and land use maps, and the driving forces of the spatiotemporal change were analyzed using a principal component analysis (PCA). The results indicated that, from 2000 to 2015, sloping farmland decreased by 3263 km2 in the Sichuan province. The area of gently sloping farmland (&lt;10°) decreased dramatically by 1467 km2, especially in the capital city, Chengdu, and its surrounding areas. However, the steep sloping farmland (&gt;25°) decreased by 302 km2, and was still the largest portion of total farmland in the area. The PCA analysis indicated that the main driving forces behind the changes were social and economic factors. The influence of agricultural intensification factors, such as the multiple cropping index and sown areas of crops, was relatively weak. Given the decrease in the overall slope cultivated area and the increased portion of moderately steep slope land (10–25°) in the cultivated area, special attention should be paid to the scientific conservation of sloping farmland during rapid social and economic development.

Analysis on the Method of Coordination Evaluation of Regional Statistical Indicators—An Empirical Study Based on Business Cycle Theory and State Space Model

Based on the preliminary judgment of the business cycle theory, there is a certain degree of disharmony among the statistical indicators in Sichuan Province. The elastic coefficient is used to construct the coordination degree measurement method, and the variable parameter state space model is constructed to compare the GDP and social commodity retail total in various regions of Sichuan. The coordination of the empirical test shows that the coordination degree between the statistical indicators of most cities and states in Sichuan is rising, the coordination degree of a few cities and states is low; the overall coordination degree is slightly left-biased. In addition, there is no necessary link between the degree of coordination between statistical indicators in various regions and the level of regional economic development.

Monitoring the Effects of the Grain to Green Projects Using Landscape Metrics: A Case Study in Eastern Sichuan, China

Eastern Sichuan is an important ecological barrier in the upper reaches of the Yangtze River. Based on 1990, 1995, 2000, 2005, 2010 and 2015 Landsat TM / ETM image data, the dynamics change of land use is analysed by using remote sensing and GIS software. The trend of change measures the effect of the Grain to Green Projects in the study area. The results show that farmland was the main type of land, and building land had the most dynamic degree during the period of studying. Since the implementation of the Grain to Green Projects in 2000, the area of farmland has decreased and the patches have been fragmented. The area of forestland has increased and the connectivity of patches has increased. The shape of grass types has tended to be regular. At the same time, the overall landscape diversity has increased and the spatial layout has become increasingly regularized. This study provides a theoretical support for policy-making of environmental protection and management in Eastern Sichuan Region of Sichuan Province.

Mosquitoes, midges and related arboviruses in southeast Sichuan province

Objective: To investigate the distribution patterns of mosquitoes, midges and related arboviruses in Sichuan province. Methods: Blood-sucking insects were collected from houses and pens, using the ultraviolet lights. Mosquito samples were classified according to morphologic characteristics and then stored at liquid nitrogen. All samples were incubated with BHK-21 and C6/36 cells for virus isolation and then detected for their viral genes. Sequences of the virus were identified and analyzed by molecular biological software, such as BioEdit 7.0.5.3, MEGA 6.0. Results: In total, 17 019 mosquitoes from 3 genera and 4 species and 12 700 midges were collected from the southeast regions of Sichuan province in 2016 and 2017. Among them, 79.4% (13 519/17 019) belonged to Culex tritaeniorhynchus with 11.1% (1 897/17 019) as Armigeres subalbatus, 5.5% (930/17 019) were Anopheles sinensis and 4.0% (673/17 019) were Anopheles sinensis 3 virus strains that isolated from Culex tritaeniorhynchus were identified as typeⅠ Japanese encephalitis virus. Seven pools of mosquitoes isolated from Hejiang county were identified Japanese encephalitis virus gene positive through PCR amplification. With 4 pool midges were detected positive for Akabane virus through PCR gene amplification while midges samples didn't have virus isolates. Conclusions: Culex tritaeniorhynchus appeared the predominant species in the southeast regions of Sichuan. Japanese encephalitis virus transmitted by mosquitoes and Akabane virus by midges were prevalent in southeast Sichuan province.