In karst regions,the spatial heterogeneity of soil mineral oxides and environmental variables is still not clear.We investigated the spatial heterogeneity of SiO2,Al2O3,Fe2O3,CaO,MgO,P2O5,K2O,and MnO contents in the s...In karst regions,the spatial heterogeneity of soil mineral oxides and environmental variables is still not clear.We investigated the spatial heterogeneity of SiO2,Al2O3,Fe2O3,CaO,MgO,P2O5,K2O,and MnO contents in the soils of slope land,plantation forest,secondary forest,and primary forest,as well as their relationships with environmental variables in a karst region of Southwest China.Geostatistics,principal component analysis(PCA),and canonical correlation analysis(CCA)were applied to analyze the field data.The results show that SiO2was the predominant mineral in the soils(45.02%–67.33%),followed by Al2O3and Fe2O3.Most soil mineral oxide components had a strong spatial dependence,except for CaO,MgO,and P2O5in the plantation forest,MgO and P2O5in the secondary forest,and CaO in the slope land.Dimensionality reduction in PCA was not appropriate due to the strong spatial heterogeneity in the ecosystems.Soil mineral oxide components,the main factors in all ecosystems,had greater influences on vegetation than those of conventional soil properties.There were close relationships between soil mineral oxide components and vegetation,topography,and conventional soil properties.Mineral oxide components affected species diversity,organic matter and nitrogen levels.展开更多
Mountain glaciers in China are an important water source for both China and adjoining countries, and therefore their adaptation to glacier change is crucial in relation to maintaining populations. This study aims to i...Mountain glaciers in China are an important water source for both China and adjoining countries, and therefore their adaptation to glacier change is crucial in relation to maintaining populations. This study aims to improve our understanding of glacial vulnerability to climate change to establish adaptation strategies. A glacial numerical model is developed using spatial principle component analysis （SPCA） supported by remote sensing （RS） and geographical information system （GIS） technologies. The model contains nine factors--slope, aspect, hillshade, elevation a.s.l., air temperature, precipitation, glacial area change percentage, glacial type and glacial area, describing topography, climate, and glacier characteristics. The vulnerability of glaciers to climate change is evaluated during the period of 1961-2007 on a regional scale, and in the 2030s and 2050s based on projections of air temperature and precipitation changes under the IPCC RCP6.0 scenario and of glacier change in the 21st century. Glacial vulnerability is graded into five levels： potential, light, medial, heavy, and very heavy, using natural breaks classification （NBC）. The spatial distribution of glacial vulnerability and its temporal changes in the 21st century for the RCP6.0 scenario are analyzed, and the factors influencing vulnerability are discussed. Results show that mountain glaciers in China are very vulnerable to climate change, and 41.2% of glacial areas fall into the levels of heavy and very heavy vulnerability in the period 1961-2007. This is mainly explained by topographical exposure and the high sensitivity of glaciers to climate change. Trends of glacial vulnerability are projected to decline in the 2030s and 2050s, but a declining trend is still high in some regions. In addition to topographical factors, variation in precipitation in the 2030s and 2050s is found to be crucial.展开更多
Objective To determine the incidence, course, potential risk factors, and outcomes of noninfectious fever developed in patients after aortic surgery. Methods Patients who received operation for aortic aneurysm or dis...Objective To determine the incidence, course, potential risk factors, and outcomes of noninfectious fever developed in patients after aortic surgery. Methods Patients who received operation for aortic aneurysm or dissection in our center from January 2006 to January 2008 were reviewed. Patients who met one of the following criteria were excluded： having a known source of infection during hospitalization; having a preoperative oral temperature greater than or equal to 38.0℃; undertaking emergency surgery; having incomplete data. Univariate analysis was performed in patients with noninfectious postoperative fever and those without, with respect to demographics, intraoperative data, etc. Risk factors for postoperative fever were considered for the muhivariate logistic regression model if they had a P value less than 0.10 in the univariate analysis. Results Totally 463 patients undergoing aortic surgery were enrolled for full review. Among them, 345 （74.5%） patients had noninfectious postoperative fever, the other 118 （25.5%） patients didn＇t develop postoperative fever. Univariate analysis demonstrated that several risk factors were associated with the development of noninfectious postoperative fever, including weight, surgical procedure, minimum intraoperative bladder temperature, temperature upon intensive care unit （ICU） admission, discharge, and during ICU stay, as well as blood transfusion. In a further multivariate analysis, surgical site of thoracic and thoracoabdominal aorta （odds ratio： 4.861; 95% confidence interval： 3.029-5.801; P=0.004）, lower minimum intraoperative bladder temperature （odds ratio： 1.117; 95% confidence interval： 1.01-1.24; P=0.04）, and higher temperature on admission to the ICU （odds ratio： 2.57; 95% confidence interval： 1.28-5.18; P=0.008） were found to be significant predictors for noninfectious postoperative fever. No difference was found between the febrile and afebrile patients with regard to postoperative hospitalization duration （P=0.558） or total medical costs （P=0.896）. Conclusion Noninfectious postoperative fever following aortic surgery is very common and closely related with perioperative interventions.展开更多
The land issue remains a colonial legacy which Africa must resolve to facilitate the region＇s Before colonialism land was considered by communities as economic rather than a socio-economic advancements political reso...The land issue remains a colonial legacy which Africa must resolve to facilitate the region＇s Before colonialism land was considered by communities as economic rather than a socio-economic advancements political resource. Agricultural communities vacated land no longer fertile or useful for pasture. Conflicts over parcels of land were therefore rare and if they did occur often resulted in migration. Scramble over parcels of land was thus for need. However, with European scramble and arbitrary partition of Africa in the nineteenth century, formal boundaries were established by colonialists between colonies, a policy later pursued by colonial administrators between communities within colonies. Colonial policies and decolonization process in some colonies complicated the land problem, resulting in the scramble over land for greed by the newly independent states and communities. Land scrambled for greed engendered generalized conflicts. This paper thus intends to argue that the scramble over land for greed made land more a factor of contention than peace in Africa. A chronological-illustrative method, with references from the different geographical divide in Africa was adopted to explore the changing land usage and faces of land conflicts in Africa with the finality that land question in the region is largely a colonial problem.展开更多
基金Under the auspices of Chinese Academy Sciences Action Plan for the Development of Western China(No.KZCX2-XB3-10)Major State Basic Research Development Program of China(No.2011BAC09B02)+2 种基金Strategic Priority Research Program-Climate Change:Carbon Budget and Related Issues'of Chinese Academy of Sciences(No.XDA05070404,XDA05050205)National Natural Science Foundation of China(No.31070425,31000224,U1033004)Guangxi Provincial Program of Distinguished Expert in China
文摘In karst regions,the spatial heterogeneity of soil mineral oxides and environmental variables is still not clear.We investigated the spatial heterogeneity of SiO2,Al2O3,Fe2O3,CaO,MgO,P2O5,K2O,and MnO contents in the soils of slope land,plantation forest,secondary forest,and primary forest,as well as their relationships with environmental variables in a karst region of Southwest China.Geostatistics,principal component analysis(PCA),and canonical correlation analysis(CCA)were applied to analyze the field data.The results show that SiO2was the predominant mineral in the soils(45.02%–67.33%),followed by Al2O3and Fe2O3.Most soil mineral oxide components had a strong spatial dependence,except for CaO,MgO,and P2O5in the plantation forest,MgO and P2O5in the secondary forest,and CaO in the slope land.Dimensionality reduction in PCA was not appropriate due to the strong spatial heterogeneity in the ecosystems.Soil mineral oxide components,the main factors in all ecosystems,had greater influences on vegetation than those of conventional soil properties.There were close relationships between soil mineral oxide components and vegetation,topography,and conventional soil properties.Mineral oxide components affected species diversity,organic matter and nitrogen levels.
基金supported by grants from the National Basic Research Program of China (2013CBA01808)the National Natural Science Foundation of China (41271088)
文摘Mountain glaciers in China are an important water source for both China and adjoining countries, and therefore their adaptation to glacier change is crucial in relation to maintaining populations. This study aims to improve our understanding of glacial vulnerability to climate change to establish adaptation strategies. A glacial numerical model is developed using spatial principle component analysis （SPCA） supported by remote sensing （RS） and geographical information system （GIS） technologies. The model contains nine factors--slope, aspect, hillshade, elevation a.s.l., air temperature, precipitation, glacial area change percentage, glacial type and glacial area, describing topography, climate, and glacier characteristics. The vulnerability of glaciers to climate change is evaluated during the period of 1961-2007 on a regional scale, and in the 2030s and 2050s based on projections of air temperature and precipitation changes under the IPCC RCP6.0 scenario and of glacier change in the 21st century. Glacial vulnerability is graded into five levels： potential, light, medial, heavy, and very heavy, using natural breaks classification （NBC）. The spatial distribution of glacial vulnerability and its temporal changes in the 21st century for the RCP6.0 scenario are analyzed, and the factors influencing vulnerability are discussed. Results show that mountain glaciers in China are very vulnerable to climate change, and 41.2% of glacial areas fall into the levels of heavy and very heavy vulnerability in the period 1961-2007. This is mainly explained by topographical exposure and the high sensitivity of glaciers to climate change. Trends of glacial vulnerability are projected to decline in the 2030s and 2050s, but a declining trend is still high in some regions. In addition to topographical factors, variation in precipitation in the 2030s and 2050s is found to be crucial.
文摘Objective To determine the incidence, course, potential risk factors, and outcomes of noninfectious fever developed in patients after aortic surgery. Methods Patients who received operation for aortic aneurysm or dissection in our center from January 2006 to January 2008 were reviewed. Patients who met one of the following criteria were excluded： having a known source of infection during hospitalization; having a preoperative oral temperature greater than or equal to 38.0℃; undertaking emergency surgery; having incomplete data. Univariate analysis was performed in patients with noninfectious postoperative fever and those without, with respect to demographics, intraoperative data, etc. Risk factors for postoperative fever were considered for the muhivariate logistic regression model if they had a P value less than 0.10 in the univariate analysis. Results Totally 463 patients undergoing aortic surgery were enrolled for full review. Among them, 345 （74.5%） patients had noninfectious postoperative fever, the other 118 （25.5%） patients didn＇t develop postoperative fever. Univariate analysis demonstrated that several risk factors were associated with the development of noninfectious postoperative fever, including weight, surgical procedure, minimum intraoperative bladder temperature, temperature upon intensive care unit （ICU） admission, discharge, and during ICU stay, as well as blood transfusion. In a further multivariate analysis, surgical site of thoracic and thoracoabdominal aorta （odds ratio： 4.861; 95% confidence interval： 3.029-5.801; P=0.004）, lower minimum intraoperative bladder temperature （odds ratio： 1.117; 95% confidence interval： 1.01-1.24; P=0.04）, and higher temperature on admission to the ICU （odds ratio： 2.57; 95% confidence interval： 1.28-5.18; P=0.008） were found to be significant predictors for noninfectious postoperative fever. No difference was found between the febrile and afebrile patients with regard to postoperative hospitalization duration （P=0.558） or total medical costs （P=0.896）. Conclusion Noninfectious postoperative fever following aortic surgery is very common and closely related with perioperative interventions.
文摘The land issue remains a colonial legacy which Africa must resolve to facilitate the region＇s Before colonialism land was considered by communities as economic rather than a socio-economic advancements political resource. Agricultural communities vacated land no longer fertile or useful for pasture. Conflicts over parcels of land were therefore rare and if they did occur often resulted in migration. Scramble over parcels of land was thus for need. However, with European scramble and arbitrary partition of Africa in the nineteenth century, formal boundaries were established by colonialists between colonies, a policy later pursued by colonial administrators between communities within colonies. Colonial policies and decolonization process in some colonies complicated the land problem, resulting in the scramble over land for greed by the newly independent states and communities. Land scrambled for greed engendered generalized conflicts. This paper thus intends to argue that the scramble over land for greed made land more a factor of contention than peace in Africa. A chronological-illustrative method, with references from the different geographical divide in Africa was adopted to explore the changing land usage and faces of land conflicts in Africa with the finality that land question in the region is largely a colonial problem.
