Spectral index methodology has been widely used in Leaf Area Index(LAI) retrieval at different spatial scales. There are differences in the spectral response of different remote sensors and thus spectral scale effect ...Spectral index methodology has been widely used in Leaf Area Index(LAI) retrieval at different spatial scales. There are differences in the spectral response of different remote sensors and thus spectral scale effect generated during the use of spectral indices to retrieve LAI. In this study, PROSPECT, leaf optical properties model and Scattering by Arbitrarily Inclined Layers(SAIL) model, were used to simulate canopy spectral reflectance with a bandwidth of 5 nm and a Gaussian spectral response function was employed to simulate the spectral data at six bandwidths ranging from 10 to 35 nm. Additionally, for bandwidths from 5 to 35 nm, the correlation between the spectral index and LAI, and the sensitivities of the spectral index to changes in LAI and bandwidth were analyzed. Finally, the reflectance data at six bandwidths ranging from 40 to 65 nm were used to verify the spectral scale effect generated during the use of the spectral index to retrieve LAI. Results indicate that Vegetation Index of the Universal Pattern Decomposition(VIUPD) had the highest accuracy during LAI retrieval. Followed by Normalized Difference Vegetation Index(NDVI), Modified Simple Ratio Indices(MSRI) and Triangle Vegetation Index(TVI), although the coefficient of determination R^2 was higher than 0.96, the retrieved LAI values were less than the actual value and thus lacked validity. Other spectral indices were significantly affected by the spectral scale effect with poor retrieval results. In this study, VIUPD, which exhibited a relatively good correlation and sensitivity to LAI, was less affected by the spectral scale effect and had a relatively good retrieval capability. This conclusion supports a purported feature independent of the sensor of this model and also confirms the great potential of VIUPD for retrieval of physicochemical parameters of vegetation using multi-source remote sensing data.展开更多
Objective：To compare the treating effects of different intramedullary nailing methods on tibial fractures in adults.Methods：Literature reports in both Chinese and English languages were retrieved （from the earliest...Objective：To compare the treating effects of different intramedullary nailing methods on tibial fractures in adults.Methods：Literature reports in both Chinese and English languages were retrieved （from the earliest available records to October 1,2013） from the PubMed,FMJS,CNKI,Wanfang Data using randomized controlled trials （RCTs） to compare reamed and unreamed intramedullary nailing for treatment of tibial fractures.Methodological quality of the trials was critically assessed,and relevant data were extracted.Statistical software Revman 5.0 was used for data-analysis.Results：A total of 12 randomized controlled trials,comprising 985 patients （475 in the unreamed group and 510 in the reamed group）,were eligible for inclusion in this meta-analysis.The results of metaanalysis showed that there were no statistically significant differences between the two methods in the reported outcomes of infection （RR=0.64; 95％CI,0.39 to 1.07;P=0.09）,compartment syndrome （RR=1.44; 95％CI,0.8to 2.41; P=0.16）,thrombosis （RR=1.29; 95％CI,0.43to 3.87; P=0.64）,time to union （WMD=5.01; 95％CI,-1.78 to 11.80; P=0.15）,delayed union （nonunion）（RR=1.56; 95％CI,0.97 to 2.49; P=0.06）,malunion （RR=1.75; 95％CI,1.00 to 3.08; P=0.05） and knee pain （RR=0.94; 95％CI,0.73 to 1.22; P=0.66）.But there was a significantly higher fixation failure rate in the unreamed group than in the reamed group （RR=4.29; 95％CI,2.58to 7.14; P＜0.00001）.Conclusion：There is no significant difference in the reamed and unreamed intramedullary nailing for the treatment of tibial fractures,but our result recommends reamed nails for the treatment of closed tibial fractures for their lower fixation failure rate.展开更多
基金National Natural Science Foundation of China(No.41401002)Jilin Province Science Foundation for Youths(No.20160520077JH)
文摘Spectral index methodology has been widely used in Leaf Area Index(LAI) retrieval at different spatial scales. There are differences in the spectral response of different remote sensors and thus spectral scale effect generated during the use of spectral indices to retrieve LAI. In this study, PROSPECT, leaf optical properties model and Scattering by Arbitrarily Inclined Layers(SAIL) model, were used to simulate canopy spectral reflectance with a bandwidth of 5 nm and a Gaussian spectral response function was employed to simulate the spectral data at six bandwidths ranging from 10 to 35 nm. Additionally, for bandwidths from 5 to 35 nm, the correlation between the spectral index and LAI, and the sensitivities of the spectral index to changes in LAI and bandwidth were analyzed. Finally, the reflectance data at six bandwidths ranging from 40 to 65 nm were used to verify the spectral scale effect generated during the use of the spectral index to retrieve LAI. Results indicate that Vegetation Index of the Universal Pattern Decomposition(VIUPD) had the highest accuracy during LAI retrieval. Followed by Normalized Difference Vegetation Index(NDVI), Modified Simple Ratio Indices(MSRI) and Triangle Vegetation Index(TVI), although the coefficient of determination R^2 was higher than 0.96, the retrieved LAI values were less than the actual value and thus lacked validity. Other spectral indices were significantly affected by the spectral scale effect with poor retrieval results. In this study, VIUPD, which exhibited a relatively good correlation and sensitivity to LAI, was less affected by the spectral scale effect and had a relatively good retrieval capability. This conclusion supports a purported feature independent of the sensor of this model and also confirms the great potential of VIUPD for retrieval of physicochemical parameters of vegetation using multi-source remote sensing data.
文摘Objective：To compare the treating effects of different intramedullary nailing methods on tibial fractures in adults.Methods：Literature reports in both Chinese and English languages were retrieved （from the earliest available records to October 1,2013） from the PubMed,FMJS,CNKI,Wanfang Data using randomized controlled trials （RCTs） to compare reamed and unreamed intramedullary nailing for treatment of tibial fractures.Methodological quality of the trials was critically assessed,and relevant data were extracted.Statistical software Revman 5.0 was used for data-analysis.Results：A total of 12 randomized controlled trials,comprising 985 patients （475 in the unreamed group and 510 in the reamed group）,were eligible for inclusion in this meta-analysis.The results of metaanalysis showed that there were no statistically significant differences between the two methods in the reported outcomes of infection （RR=0.64; 95％CI,0.39 to 1.07;P=0.09）,compartment syndrome （RR=1.44; 95％CI,0.8to 2.41; P=0.16）,thrombosis （RR=1.29; 95％CI,0.43to 3.87; P=0.64）,time to union （WMD=5.01; 95％CI,-1.78 to 11.80; P=0.15）,delayed union （nonunion）（RR=1.56; 95％CI,0.97 to 2.49; P=0.06）,malunion （RR=1.75; 95％CI,1.00 to 3.08; P=0.05） and knee pain （RR=0.94; 95％CI,0.73 to 1.22; P=0.66）.But there was a significantly higher fixation failure rate in the unreamed group than in the reamed group （RR=4.29; 95％CI,2.58to 7.14; P＜0.00001）.Conclusion：There is no significant difference in the reamed and unreamed intramedullary nailing for the treatment of tibial fractures,but our result recommends reamed nails for the treatment of closed tibial fractures for their lower fixation failure rate.
