Irritable bowel syndrome (IBS) is a common gastro-intestinal (GI) disorder that considerably reduces the quality of life. It further represents an economic burden on society due to the high consumption of healthcare r...Irritable bowel syndrome (IBS) is a common gastro-intestinal (GI) disorder that considerably reduces the quality of life. It further represents an economic burden on society due to the high consumption of healthcare resources and the non-productivity of IBS patients. The diagnosis of IBS is based on symptom assessment and the Rome Ⅲ criteria. A combination of the Rome Ⅲ criteria, a physical examination, blood tests, gastros-copy and colonoscopy with biopsies is believed to be necessary for diagnosis. Duodenal chromogranin A cell density is a promising biomarker for the diagnosis of IBS. The pathogenesis of IBS seems to be multifactorial, with the following factors playing a central role in the pathogenesis of IBS:heritability and genetics, dietary/intestinal microbiota, low-grade inflammation, and disturbances in the neuroendocrine system (NES) of the gut. One hypothesis proposes that the cause of IBS is an altered NES, which would cause abnormal GI motility, secretions and sensation. All of these abnormalities are characteristic of IBS. Alterations in the NES could be the result of one or more of the following:genetic factors, dietary intake, intestinal flora, or lowgrade inflammation. Post-infectious IBS (PI-IBS) and inflammatory bowel disease-associated IBS (IBD-IBS) represent a considerable subset of IBS cases. Patients with PI-and IBD-IBS exhibit low-grade mucosal inflammation, as well as abnormalities in the NES of the gut.展开更多
Many factors can affect the sediment deposition and soil erosion process in riparian zone, including terrain, sediment transport and water level fluctuations. Clarifying the factors influencing sediment deposition pro...Many factors can affect the sediment deposition and soil erosion process in riparian zone, including terrain, sediment transport and water level fluctuations. Clarifying the factors influencing sediment deposition process in the riparian zone of the Three Gorges Reservoirs is an important problem to determine the key area of sediment deposition and its trend of development in the study area. In order to reveal the influence of these environmental factors on the sediment deposition in riparian zone of the Three Gorges Reservoir, this study investigated 1） the amount of deposited sediment in different environmental conditions, 2） the potential factors affecting sediment deposition in riparian zone of the Three Gorges Reservoir, 3） the relationship between the deposited sediment amount and these factors previously mentioned using correlation analysis, and 4） the influence of human activities considered as an additional factor. This study found that 1） slope gradient, elevation, inundating duration and human activities were the main factors influencing sedimentation in riparian zone of the Three Gorges Reservoir, and 2） the impact of each factor varied with spaces. Specifically, in the upper reach from Jiangjin to Fuling, human activities such as gravel dredging, bank revetment and ports and wharfs constructing disturbed considerable amounts of deposited sediment, as a result, there was no natural law to dictate the distribution. In the middle reach from Fuling to Fengjie, slope gradient and inundating duration were the controlling factors, and the sediment deposition amount was greater in the areas with a gentler slope or lower elevation. Water flow on gentler slopes generally had lower velocity, resulting in more sediment to deposit. Sites with lower elevations would be drowned by sediment-laden flow with a longer duration resulting from hydrologic regime controlled by the operating strategy of the Three Gorges Reservoir, leading to a larger amount of sediment deposition. In the lower reach from Fengjie to Zigni, slope gradient was similar to the middle reach, performing a primary factor, while other factors showed little relationship with sediment amount.展开更多
The study investigates the nonlinear heart rate variability indices in different seasons and their dependence on current meteorological factors. The study included 61 relatively healthy student volunteers, their age w...The study investigates the nonlinear heart rate variability indices in different seasons and their dependence on current meteorological factors. The study included 61 relatively healthy student volunteers, their age were 19-23 and they were examined repeatedly in different seasons. The HRV （heart rate variability） recording was performed with the use of the hardware-software complex ＂Varikard 2.51＂ Nonlinear HRV indices were calculated by means of the Kubios HRV 2.1. The following indicators： SD1, SD2, SD1/SD2, D2, DFA, SampEn and quantitative indicators of recurrence analysis （RQA ）---Lmean, Lmax, REC, DET, ShanEn had been analyzed. Statistical analysis was performed using the Statistica 6.0. For the detection of between-group differences were used Repeated Measures ANOVA, and the dependence of nonlinear HRV indices on meteorological was analyzed with the use of multiple non-linear regression. The investigation showed a relative increase in SampEn and the reduction of al in winter and spring seasons, strengthening relationships SampEn correlation with other indicators in the winter season as well as the dependence SampEn on meteorological factors in summer. The detected changes can be considered as the realization of adaptive response of a healthy body.展开更多
Tourism has emerged as a major driving force in the growth and expansion of rural settlements. After several studies revealed spatial differentiation of touristization among rural settlements, studies were conducted t...Tourism has emerged as a major driving force in the growth and expansion of rural settlements. After several studies revealed spatial differentiation of touristization among rural settlements, studies were conducted to explain this phenomenon. However, most of these studies explained spatial differentiation of rural touristization in a qualitative way. More robust and detailed quantitative results are needed to evaluate the relative roles of different factors. In this study, which takes Yesanpo tourism as a case study, the Geo-detector method was introduced to evaluate determining factors of rural touristization. Results show that ＂distance to core entry＂, ＂tourist number and sojourn time＂, and ＂distance to the nearest scenic area＂ have had a strong effect on the rural touristization in Ye- sanpo, whereas ＂distance to river＂, ＂elevation＂, ＂distance to main road＂, and ＂slope＂ have had a weak influence. The latter did, however, contribute a lot to touristization when interacting with ＂distance to core entry＂, ＂tourist number and sojourn time＂, and ＂distance to the nearest scenic＂, indicating the importance of these four factors. Higher rural touristization occurred in the zone near the core entry, with many tourists, long sojourn times, and proximity to the scenic area.展开更多
Spatial differentiation in forest transition was measured in terms of space transition and function transition using the exploratory spatial data analysis method（ESDA） and data from 2004—2014 for Zunyi city,Guizhou...Spatial differentiation in forest transition was measured in terms of space transition and function transition using the exploratory spatial data analysis method（ESDA） and data from 2004—2014 for Zunyi city,Guizhou province,China.The validity of factors affecting forest transition was analyzed by constructing radial basis function neural networks（RBFNN） based on the data processing system（DPS）.Our results will provide references for scientific understanding of the potential mechanism underlying forest transition in mountainous areas.We found that Global Moran＇s I of space transition and function transition of forest land was 0.0336 and 0.2323,respectively.This suggests a significant positive correlation in spatial distribution of space transition and function transition of forest land,and significant spatial aggregation.The Global Moran＇s I of function transition was higher than that of space transition,and the spatial aggregation characteristics of function transition were more significant than for space transition.The Global Moran＇s I at each time period tended to increase,and the spatial aggregation degree of the function transition and space transition was further enhanced.Hot and cold spots of space transition of forest land stably evolved,suggesting a minor spatial difference in forest land among different administrative units at the county level.The number of hot spots at the county level in function transition increased.Hot spots were intensively distributed at the western edge and continuously distributed in the northeast.The space transition and function transition of forest land were both greatly influenced by urbanization rate and second and third industries.The development of urbanization and industrialization was the main factor driving forest transition,suggesting a positive role of economic growth on forest transition in mountainous areas.The development of urbanization and industrialization is an effective approach to forest transition in mountainous areas.展开更多
Cultivated land pressure is often used to reflect the shortage of cultivated land resources. By using the methods of the Cultivated Land Pressure Index, coefficient of variation and cold-hot spot analysis, this paper ...Cultivated land pressure is often used to reflect the shortage of cultivated land resources. By using the methods of the Cultivated Land Pressure Index, coefficient of variation and cold-hot spot analysis, this paper analyzes the spatial-temporal differentiation pattern and dynamic change processes of cultivated land pressure in the counties of the Pearl River-Xijiang Economic Zone from 2008 to 2017, and measures the factors which influence cultivated land pressure by using Principal Component Analysis. The results show that the cultivated land pressure in the Pearl River-Xijiang Economic Zone has been in a “high pressure” state, and the Cultivated Land Pressure Index has been rising continuously from 2008 to 2017. The coefficient of variation of the Cultivated Land Pressure Index in the Pearl River-Xijiang Economic Zone and various prefecture-level cities is fluctuating and rising, which indicates that the overall spatial differences in the cultivated land pressure in this region are expanding and polarization is obvious. In addition, the area where the municipal district of the provincial capital city is located is the core area of urban development and also the area with the greatest cultivated land pressure. The spatial pattern of cultivated land pressure cold-hot spots in the Pearl River-Xijiang Economic Zone is obviously heterogeneous, in which the Pearl River Economic Zone is the main hot spot gathering area and the Xijiang Economic Zone is the main cold spot gathering area. Farmers’ income, investment in fixed assets, GDP, population and other socio-economic factors are the main factors driving the changes in the cultivated land pressure in the Pearl River-Xijiang Economic Zone. Furthermore, farming production factors, such as the multiple cropping index and grain yield per unit area,will also have an important impact on the changes in the cultivated land pressure.展开更多
Despite the rapid development of flower-viewing tourism in China in recent years,there is almost no systematic research on it.Therefore,this study analyzes the spatial and temporal distribution characteristics of flow...Despite the rapid development of flower-viewing tourism in China in recent years,there is almost no systematic research on it.Therefore,this study analyzes the spatial and temporal distribution characteristics of flower-viewing tourism and its influencing factors in China using the spatial statistical analysis methods and the geographic detector method.The study uses the Point-of-Interest data of flower-viewing tourist attractions from networks such as Qunar and Ctrip,the flower observation data from China Phenological Observation Network,Chinese network news,and Weibo,and the statistical data from yearbooks.The results are as follows:1)The spatial attribution type of flower-viewing tourism in China is aggregated into areas,including two high-density aggregated areas,three medium-density aggregated areas,and one general-density aggregated area.Furthermore,five major types of flower-viewing tourist attractions have formed several aggregated areas.2)The time of flower viewing in China starts from about February and lasts about eight months till October each year.Florescence and flowering time of different ornamental flowers in different regions are different.3)The spatial and temporal distribution characteristics of flower-viewing tourism in China are mainly affected by ornamental flower phenology,spatial distribution characteristics of flower-viewing resources,regional permanent population size,youth population size,female population size,regional GDP,and added value of the tertiary sector.These conclusions clarify the spatial and temporal distribution characteristics of flower-viewing tourism and its influencing factors in China.They could provide a scientific basis and useful reference for the coordination and sustainable development of regional flower-viewing tourism in China.展开更多
文摘Irritable bowel syndrome (IBS) is a common gastro-intestinal (GI) disorder that considerably reduces the quality of life. It further represents an economic burden on society due to the high consumption of healthcare resources and the non-productivity of IBS patients. The diagnosis of IBS is based on symptom assessment and the Rome Ⅲ criteria. A combination of the Rome Ⅲ criteria, a physical examination, blood tests, gastros-copy and colonoscopy with biopsies is believed to be necessary for diagnosis. Duodenal chromogranin A cell density is a promising biomarker for the diagnosis of IBS. The pathogenesis of IBS seems to be multifactorial, with the following factors playing a central role in the pathogenesis of IBS:heritability and genetics, dietary/intestinal microbiota, low-grade inflammation, and disturbances in the neuroendocrine system (NES) of the gut. One hypothesis proposes that the cause of IBS is an altered NES, which would cause abnormal GI motility, secretions and sensation. All of these abnormalities are characteristic of IBS. Alterations in the NES could be the result of one or more of the following:genetic factors, dietary intake, intestinal flora, or lowgrade inflammation. Post-infectious IBS (PI-IBS) and inflammatory bowel disease-associated IBS (IBD-IBS) represent a considerable subset of IBS cases. Patients with PI-and IBD-IBS exhibit low-grade mucosal inflammation, as well as abnormalities in the NES of the gut.
基金funded by the Chinese Academy of Sciences(Grant Nos.KFJ-EW-STS-008,KFJSW-STS-175)
文摘Many factors can affect the sediment deposition and soil erosion process in riparian zone, including terrain, sediment transport and water level fluctuations. Clarifying the factors influencing sediment deposition process in the riparian zone of the Three Gorges Reservoirs is an important problem to determine the key area of sediment deposition and its trend of development in the study area. In order to reveal the influence of these environmental factors on the sediment deposition in riparian zone of the Three Gorges Reservoir, this study investigated 1） the amount of deposited sediment in different environmental conditions, 2） the potential factors affecting sediment deposition in riparian zone of the Three Gorges Reservoir, 3） the relationship between the deposited sediment amount and these factors previously mentioned using correlation analysis, and 4） the influence of human activities considered as an additional factor. This study found that 1） slope gradient, elevation, inundating duration and human activities were the main factors influencing sedimentation in riparian zone of the Three Gorges Reservoir, and 2） the impact of each factor varied with spaces. Specifically, in the upper reach from Jiangjin to Fuling, human activities such as gravel dredging, bank revetment and ports and wharfs constructing disturbed considerable amounts of deposited sediment, as a result, there was no natural law to dictate the distribution. In the middle reach from Fuling to Fengjie, slope gradient and inundating duration were the controlling factors, and the sediment deposition amount was greater in the areas with a gentler slope or lower elevation. Water flow on gentler slopes generally had lower velocity, resulting in more sediment to deposit. Sites with lower elevations would be drowned by sediment-laden flow with a longer duration resulting from hydrologic regime controlled by the operating strategy of the Three Gorges Reservoir, leading to a larger amount of sediment deposition. In the lower reach from Fengjie to Zigni, slope gradient was similar to the middle reach, performing a primary factor, while other factors showed little relationship with sediment amount.
文摘The study investigates the nonlinear heart rate variability indices in different seasons and their dependence on current meteorological factors. The study included 61 relatively healthy student volunteers, their age were 19-23 and they were examined repeatedly in different seasons. The HRV （heart rate variability） recording was performed with the use of the hardware-software complex ＂Varikard 2.51＂ Nonlinear HRV indices were calculated by means of the Kubios HRV 2.1. The following indicators： SD1, SD2, SD1/SD2, D2, DFA, SampEn and quantitative indicators of recurrence analysis （RQA ）---Lmean, Lmax, REC, DET, ShanEn had been analyzed. Statistical analysis was performed using the Statistica 6.0. For the detection of between-group differences were used Repeated Measures ANOVA, and the dependence of nonlinear HRV indices on meteorological was analyzed with the use of multiple non-linear regression. The investigation showed a relative increase in SampEn and the reduction of al in winter and spring seasons, strengthening relationships SampEn correlation with other indicators in the winter season as well as the dependence SampEn on meteorological factors in summer. The detected changes can be considered as the realization of adaptive response of a healthy body.
基金National Natural Science Foundation of China(41671151)
文摘Tourism has emerged as a major driving force in the growth and expansion of rural settlements. After several studies revealed spatial differentiation of touristization among rural settlements, studies were conducted to explain this phenomenon. However, most of these studies explained spatial differentiation of rural touristization in a qualitative way. More robust and detailed quantitative results are needed to evaluate the relative roles of different factors. In this study, which takes Yesanpo tourism as a case study, the Geo-detector method was introduced to evaluate determining factors of rural touristization. Results show that ＂distance to core entry＂, ＂tourist number and sojourn time＂, and ＂distance to the nearest scenic area＂ have had a strong effect on the rural touristization in Ye- sanpo, whereas ＂distance to river＂, ＂elevation＂, ＂distance to main road＂, and ＂slope＂ have had a weak influence. The latter did, however, contribute a lot to touristization when interacting with ＂distance to core entry＂, ＂tourist number and sojourn time＂, and ＂distance to the nearest scenic＂, indicating the importance of these four factors. Higher rural touristization occurred in the zone near the core entry, with many tourists, long sojourn times, and proximity to the scenic area.
基金National key basic research and development program(2015CB452706)National Natural Science Foundation of China(41361021+1 种基金41771115)Guizhou "thousand"level innovative talents support project in 2015(111-0317003)
文摘Spatial differentiation in forest transition was measured in terms of space transition and function transition using the exploratory spatial data analysis method（ESDA） and data from 2004—2014 for Zunyi city,Guizhou province,China.The validity of factors affecting forest transition was analyzed by constructing radial basis function neural networks（RBFNN） based on the data processing system（DPS）.Our results will provide references for scientific understanding of the potential mechanism underlying forest transition in mountainous areas.We found that Global Moran＇s I of space transition and function transition of forest land was 0.0336 and 0.2323,respectively.This suggests a significant positive correlation in spatial distribution of space transition and function transition of forest land,and significant spatial aggregation.The Global Moran＇s I of function transition was higher than that of space transition,and the spatial aggregation characteristics of function transition were more significant than for space transition.The Global Moran＇s I at each time period tended to increase,and the spatial aggregation degree of the function transition and space transition was further enhanced.Hot and cold spots of space transition of forest land stably evolved,suggesting a minor spatial difference in forest land among different administrative units at the county level.The number of hot spots at the county level in function transition increased.Hot spots were intensively distributed at the western edge and continuously distributed in the northeast.The space transition and function transition of forest land were both greatly influenced by urbanization rate and second and third industries.The development of urbanization and industrialization was the main factor driving forest transition,suggesting a positive role of economic growth on forest transition in mountainous areas.The development of urbanization and industrialization is an effective approach to forest transition in mountainous areas.
基金The Guangdong Education Science Planning Project(2019GXJK080)The Guangdong Philosophy and Social Science Planning Project(GD19YYJ03)The Guangdong Coastal Economic Belt Development Research Institute 2020 Special Project(YJY202002).
文摘Cultivated land pressure is often used to reflect the shortage of cultivated land resources. By using the methods of the Cultivated Land Pressure Index, coefficient of variation and cold-hot spot analysis, this paper analyzes the spatial-temporal differentiation pattern and dynamic change processes of cultivated land pressure in the counties of the Pearl River-Xijiang Economic Zone from 2008 to 2017, and measures the factors which influence cultivated land pressure by using Principal Component Analysis. The results show that the cultivated land pressure in the Pearl River-Xijiang Economic Zone has been in a “high pressure” state, and the Cultivated Land Pressure Index has been rising continuously from 2008 to 2017. The coefficient of variation of the Cultivated Land Pressure Index in the Pearl River-Xijiang Economic Zone and various prefecture-level cities is fluctuating and rising, which indicates that the overall spatial differences in the cultivated land pressure in this region are expanding and polarization is obvious. In addition, the area where the municipal district of the provincial capital city is located is the core area of urban development and also the area with the greatest cultivated land pressure. The spatial pattern of cultivated land pressure cold-hot spots in the Pearl River-Xijiang Economic Zone is obviously heterogeneous, in which the Pearl River Economic Zone is the main hot spot gathering area and the Xijiang Economic Zone is the main cold spot gathering area. Farmers’ income, investment in fixed assets, GDP, population and other socio-economic factors are the main factors driving the changes in the cultivated land pressure in the Pearl River-Xijiang Economic Zone. Furthermore, farming production factors, such as the multiple cropping index and grain yield per unit area,will also have an important impact on the changes in the cultivated land pressure.
基金The National Key Research and Development Program of China(2019YFB1405600)The General Project of Scientific Research Program of Beijing Municipal Education Commission(SM202110031002)+1 种基金The Humanities and Social Sciences Foundation of the Ministry of Education in China(18YJA630102)The Youth Academic Talents Project of Beijing International Studies University(21110010005).
文摘Despite the rapid development of flower-viewing tourism in China in recent years,there is almost no systematic research on it.Therefore,this study analyzes the spatial and temporal distribution characteristics of flower-viewing tourism and its influencing factors in China using the spatial statistical analysis methods and the geographic detector method.The study uses the Point-of-Interest data of flower-viewing tourist attractions from networks such as Qunar and Ctrip,the flower observation data from China Phenological Observation Network,Chinese network news,and Weibo,and the statistical data from yearbooks.The results are as follows:1)The spatial attribution type of flower-viewing tourism in China is aggregated into areas,including two high-density aggregated areas,three medium-density aggregated areas,and one general-density aggregated area.Furthermore,five major types of flower-viewing tourist attractions have formed several aggregated areas.2)The time of flower viewing in China starts from about February and lasts about eight months till October each year.Florescence and flowering time of different ornamental flowers in different regions are different.3)The spatial and temporal distribution characteristics of flower-viewing tourism in China are mainly affected by ornamental flower phenology,spatial distribution characteristics of flower-viewing resources,regional permanent population size,youth population size,female population size,regional GDP,and added value of the tertiary sector.These conclusions clarify the spatial and temporal distribution characteristics of flower-viewing tourism and its influencing factors in China.They could provide a scientific basis and useful reference for the coordination and sustainable development of regional flower-viewing tourism in China.
