In this study,short-term gully retreat was monitored from the active gullies selected in representative black soil area,using differential global positioning system(GPS).With the support of geographic information syst...In this study,short-term gully retreat was monitored from the active gullies selected in representative black soil area,using differential global positioning system(GPS).With the support of geographic information system(GIS),multi-temporal digital elevation models(DEM) were constructed from the data collected by GPS and used for further analysis.Based on the analysis of multi-temporal DEM,we discussed the erosion-deposition characteristics within gully and a developing model for black soil gully area of Northeast China was proposed.The results are:(1) The analysis of the monitored gully data in 2004 indicated that the retreat of gully head reached more than 10 m,gully area extended 170-400 m2,net gully eroded volume 220-320 m3,and gully erosion modulus 2200-4800 t?km?2?a?1.(2) Compared with the mature gully the initial gully grows rapidly,and its erosion parameters are relatively large.The erosion parameters have not only to do with flow energy,but also with the growth phase.(3) There are significant seasonal differences in gully erosion parameters.The extension of gully area and width dominates in winter and spring without marked net erosion while changes mainly occur in gully head and net erosion in rainy season.(4) It is remarkable for freeze-thaw erosion in the black soil area of NE China.The gully wall of SG2 extended 0.45 m under freeze-thaw effect in 2004,and the distance of gully head retreated maximally 6.4 m.(5) Due to freeze-thaw action and snowmelt,gully is primarily in the interior adjustment process in winter and early spring.There are much more depositions compared with that during rainy season,which can almost happen throughout the gully,while erosion mostly occurs near head,esp.for gullies having a relatively long history of development.On the other hand,the process of energy exchange with exterior dominates in rainy season.It is considered that this cyclic process is an important mechanism for gully growth in high latitude or/and high attitude regions.展开更多
The morphology of the gully longitudinal profile （GLP） is an important topographic index of the gully bottom associated with the evolution of the gullies. This index can be used to predict the development trend and ...The morphology of the gully longitudinal profile （GLP） is an important topographic index of the gully bottom associated with the evolution of the gullies. This index can be used to predict the development trend and evaluate the eroded volumes and soil losses by gullying. To depict the morphology of GLP and understand its controlling factors, the Global Positioning System Real-time Kinematic （GPS RTK） and the total station were used to measure the detail points along the gully bottom of 122 gullies at six sites of the Yuanmou dry-hot Valley. Then, nine parameters including length （Lt）, horizontal distance （Dh）, height （H）, vertical erosional area （A）, vertical curvature （Co）, concavity （Ca）, average gradient （Ga）, gully length-gradient index （GL）, normalized gully length-gradient index （Ngl）, were calculated and mapped using CASS, Excel and SPSS. The results showed that this study area is dominated by slightly concave and medium gradient GLPs, and the lithology of most gullies is sandstone and siltstone. Although different types of GLPs appear at different sites, all parameters present a positively skewed distribution. There are relatively strong correlations between several parameters： namely Lt and H, Dh and H, Lt and A, Dh and A, H and GL. Most GLPs, except three, have a best fit of exponential functions with quasi- straight shapes. Soil properties, vegetation coverage, piping erosion and topography are important factors to affect the GLP morphology. This study provides useful insight into the knowledge of GLP morphology and its influential factors that are of critical importance to prevent and control gully erosion.展开更多
Purpose： To compare the efficacy and safety of open reduction and internal fixation through ilioinguinal approach and Stoppa approach for the treatment of displaced acetabular fractures. Methods： Case-controlled tri...Purpose： To compare the efficacy and safety of open reduction and internal fixation through ilioinguinal approach and Stoppa approach for the treatment of displaced acetabular fractures. Methods： Case-controlled trials （CCTs） published from January 2010 to August 2015 that compared the ilioinguinal approach and Stoppa approach in the management of displaced acetabular fractures were retrieved from the databases of Cochrane Library, Pubmed, CNKI, and so on. Methodological quality of the trials was critically assessed. Statistical software RevMan 5.0 was used for data analysis. Results： Eight articles were included in the meta-analysis. Through comparing the efficacy and safety of ilioinguinal approach and Stoppa approach in the treatment of displaced acetabular fracture, statistical significance was found in the average operation time [WMD = 68.29, 95% CI （10.52, 126.05）, p 〈 0.05] and the median intraoperative blood loss [WMD = 142.26, 95% CI （9.30, 275.23）, p 〈 0.05]. However, there existed no statistical significance in the fracture end reset satisfaction rate [RR = 0.63, 95% CI （0.17, 2.37）, p 〉 0.05], the early complications rate [RR = 0.89, 95% CI （0.33, 2.40）, p 〉 0.05], the late complications rate [RR = 0.91, 95% CI （0.27, 3.01）, p 〉 0.05], and Harris hip score good function rate [RR = 0.52, 95% CI （0.25, 1.10）, p 〉 0.05]. Conclusion： Though both techniques can obtain satisfactory clinical functions in the treatment of displaced acetabular fractures, Stoppa approach is superior to the ilioinguinal approach in terms of operation time and intraoperative blood loss.展开更多
基金Key Project for National Natural Science Foundation of China,No.40235056The Ph.D. Programs Foundation of Ministry of Education of China, No.20030027015+3 种基金China Postdoctoral Science Foundation,No.20070410482Doctoral Foundation of University of Jinan,No.B0620National Natural Science Foundation of China,No.40672158Key Subject Foundation Supported by Shandong Province
文摘In this study,short-term gully retreat was monitored from the active gullies selected in representative black soil area,using differential global positioning system(GPS).With the support of geographic information system(GIS),multi-temporal digital elevation models(DEM) were constructed from the data collected by GPS and used for further analysis.Based on the analysis of multi-temporal DEM,we discussed the erosion-deposition characteristics within gully and a developing model for black soil gully area of Northeast China was proposed.The results are:(1) The analysis of the monitored gully data in 2004 indicated that the retreat of gully head reached more than 10 m,gully area extended 170-400 m2,net gully eroded volume 220-320 m3,and gully erosion modulus 2200-4800 t?km?2?a?1.(2) Compared with the mature gully the initial gully grows rapidly,and its erosion parameters are relatively large.The erosion parameters have not only to do with flow energy,but also with the growth phase.(3) There are significant seasonal differences in gully erosion parameters.The extension of gully area and width dominates in winter and spring without marked net erosion while changes mainly occur in gully head and net erosion in rainy season.(4) It is remarkable for freeze-thaw erosion in the black soil area of NE China.The gully wall of SG2 extended 0.45 m under freeze-thaw effect in 2004,and the distance of gully head retreated maximally 6.4 m.(5) Due to freeze-thaw action and snowmelt,gully is primarily in the interior adjustment process in winter and early spring.There are much more depositions compared with that during rainy season,which can almost happen throughout the gully,while erosion mostly occurs near head,esp.for gullies having a relatively long history of development.On the other hand,the process of energy exchange with exterior dominates in rainy season.It is considered that this cyclic process is an important mechanism for gully growth in high latitude or/and high attitude regions.
基金supported by the"National Natural Science Foundation of China(Grant No.41471232)""the Fundamental Research Funds of China West Normal University"(Grant No.16A001)"Ecological Security Key Laboratory of Sichuan Province"(Grant No.ESP201301)
文摘The morphology of the gully longitudinal profile （GLP） is an important topographic index of the gully bottom associated with the evolution of the gullies. This index can be used to predict the development trend and evaluate the eroded volumes and soil losses by gullying. To depict the morphology of GLP and understand its controlling factors, the Global Positioning System Real-time Kinematic （GPS RTK） and the total station were used to measure the detail points along the gully bottom of 122 gullies at six sites of the Yuanmou dry-hot Valley. Then, nine parameters including length （Lt）, horizontal distance （Dh）, height （H）, vertical erosional area （A）, vertical curvature （Co）, concavity （Ca）, average gradient （Ga）, gully length-gradient index （GL）, normalized gully length-gradient index （Ngl）, were calculated and mapped using CASS, Excel and SPSS. The results showed that this study area is dominated by slightly concave and medium gradient GLPs, and the lithology of most gullies is sandstone and siltstone. Although different types of GLPs appear at different sites, all parameters present a positively skewed distribution. There are relatively strong correlations between several parameters： namely Lt and H, Dh and H, Lt and A, Dh and A, H and GL. Most GLPs, except three, have a best fit of exponential functions with quasi- straight shapes. Soil properties, vegetation coverage, piping erosion and topography are important factors to affect the GLP morphology. This study provides useful insight into the knowledge of GLP morphology and its influential factors that are of critical importance to prevent and control gully erosion.
基金This study was funded by the National Natural Science Foundation of China {No.81572098） and Natural Science Foundation of Shanxi Province of China （No. 2008012011-3）.
文摘Purpose： To compare the efficacy and safety of open reduction and internal fixation through ilioinguinal approach and Stoppa approach for the treatment of displaced acetabular fractures. Methods： Case-controlled trials （CCTs） published from January 2010 to August 2015 that compared the ilioinguinal approach and Stoppa approach in the management of displaced acetabular fractures were retrieved from the databases of Cochrane Library, Pubmed, CNKI, and so on. Methodological quality of the trials was critically assessed. Statistical software RevMan 5.0 was used for data analysis. Results： Eight articles were included in the meta-analysis. Through comparing the efficacy and safety of ilioinguinal approach and Stoppa approach in the treatment of displaced acetabular fracture, statistical significance was found in the average operation time [WMD = 68.29, 95% CI （10.52, 126.05）, p 〈 0.05] and the median intraoperative blood loss [WMD = 142.26, 95% CI （9.30, 275.23）, p 〈 0.05]. However, there existed no statistical significance in the fracture end reset satisfaction rate [RR = 0.63, 95% CI （0.17, 2.37）, p 〉 0.05], the early complications rate [RR = 0.89, 95% CI （0.33, 2.40）, p 〉 0.05], the late complications rate [RR = 0.91, 95% CI （0.27, 3.01）, p 〉 0.05], and Harris hip score good function rate [RR = 0.52, 95% CI （0.25, 1.10）, p 〉 0.05]. Conclusion： Though both techniques can obtain satisfactory clinical functions in the treatment of displaced acetabular fractures, Stoppa approach is superior to the ilioinguinal approach in terms of operation time and intraoperative blood loss.
