Land cover classification(LCC) in arid regions is of great significance to the assessment, prediction, and management of land desertification. Some studies have shown that the red-edge band of RapidE ye images was eff...Land cover classification(LCC) in arid regions is of great significance to the assessment, prediction, and management of land desertification. Some studies have shown that the red-edge band of RapidE ye images was effective for vegetation identification and could improve LCC accuracy. However, there has been no investigation of the effects of RapidE ye images' red-edge band and vegetation indices on LCC in arid regions where there are spectrally similar land covers mixed with very high or low vegetation coverage information and bare land. This study focused on a typical inland arid desert region located in Dunhuang Basin of northwestern China. First, five feature sets including or excluding the red-edge band and vegetation indices were constructed. Then, a land cover classification system involving plant communities was developed. Finally, random forest algorithm-based models with different feature sets were utilized for LCC. The conclusions drawn were as follows: 1) the red-edge band showed slight contribution to LCC accuracy; 2) vegetation indices had a significant positive effect on LCC; 3) simultaneous addition of the red-edge band and vegetation indices achieved a significant overall accuracy improvement(3.46% from 86.67%). In general, vegetation indices had larger effect than the red-edge band, and simultaneous addition of them significantly increased the accuracy of LCC in arid regions.展开更多
国际上使用的人口年龄结构检验指数通常有如下几种:年龄偏好指数(Indexes of Age Preference),惠普尔指数(Whipple’s Index),迈叶斯指数(Myers’ Index),年龄准确性指数(Age—accuracy Index)和联合国年龄性别准确性指数(United Nation...国际上使用的人口年龄结构检验指数通常有如下几种:年龄偏好指数(Indexes of Age Preference),惠普尔指数(Whipple’s Index),迈叶斯指数(Myers’ Index),年龄准确性指数(Age—accuracy Index)和联合国年龄性别准确性指数(United Nations Age—Sex Accuracy Index),简称联合国综合指数。在以上这些指数中,惠普尔指数、迈叶斯指数和联合国综合指数在我国人口普查的人口年龄资料的检验中经常使用。展开更多
BackgroundPocket hematoma is one of the major complications associated with cardiovascular implantable electronic devices （CIEDs） implantation. The aim of this study is to evaluate the impact of body mass index （BM...BackgroundPocket hematoma is one of the major complications associated with cardiovascular implantable electronic devices （CIEDs） implantation. The aim of this study is to evaluate the impact of body mass index （BMI） on the occurrence of pocket hematoma after CIEDs implantation.MethodsThe study is a retrospective review of 972 patients receiving CIEDs implantation between 2008 and 2012 in a tertiary hospital.ResultsTwenty two patients （2.2%） developed severe pocket hematoma requiring re-intervention. The hematoma rate （4.6%,n = 15） of patients with a BMI of 〈 23 kg/m2 was significantly higher compared with that of patients with a BMI of≥23 kg/m2 （1.1%, n = 7,P〈 0.001）. In multivariate regression analysis, a BMI 〈 23.0 kg/m2 may be associated with the development of severe pocket hema-toma. An increase of 1.0 kg/m2 in BMI was associated with lower incidence of hematoma formation （OR： 0.84; 95% CI： 0.74-0.95;P = 0.006）.ConclusionBMI 〈 23 kg/m2 was associated with a higher incidence of pocket hematoma, requiring re-intervention. The data sup-port that great care must be taken when patients were with a lower BMI received CIEDs implantation.展开更多
基金Under the auspices of Fundamental Research Funds for Central Universities,China University of Geosciences(Wuhan)(No.CUGL150417)National Natural Science Foundation of China(No.41274036,41301026)
文摘Land cover classification(LCC) in arid regions is of great significance to the assessment, prediction, and management of land desertification. Some studies have shown that the red-edge band of RapidE ye images was effective for vegetation identification and could improve LCC accuracy. However, there has been no investigation of the effects of RapidE ye images' red-edge band and vegetation indices on LCC in arid regions where there are spectrally similar land covers mixed with very high or low vegetation coverage information and bare land. This study focused on a typical inland arid desert region located in Dunhuang Basin of northwestern China. First, five feature sets including or excluding the red-edge band and vegetation indices were constructed. Then, a land cover classification system involving plant communities was developed. Finally, random forest algorithm-based models with different feature sets were utilized for LCC. The conclusions drawn were as follows: 1) the red-edge band showed slight contribution to LCC accuracy; 2) vegetation indices had a significant positive effect on LCC; 3) simultaneous addition of the red-edge band and vegetation indices achieved a significant overall accuracy improvement(3.46% from 86.67%). In general, vegetation indices had larger effect than the red-edge band, and simultaneous addition of them significantly increased the accuracy of LCC in arid regions.
文摘BackgroundPocket hematoma is one of the major complications associated with cardiovascular implantable electronic devices （CIEDs） implantation. The aim of this study is to evaluate the impact of body mass index （BMI） on the occurrence of pocket hematoma after CIEDs implantation.MethodsThe study is a retrospective review of 972 patients receiving CIEDs implantation between 2008 and 2012 in a tertiary hospital.ResultsTwenty two patients （2.2%） developed severe pocket hematoma requiring re-intervention. The hematoma rate （4.6%,n = 15） of patients with a BMI of 〈 23 kg/m2 was significantly higher compared with that of patients with a BMI of≥23 kg/m2 （1.1%, n = 7,P〈 0.001）. In multivariate regression analysis, a BMI 〈 23.0 kg/m2 may be associated with the development of severe pocket hema-toma. An increase of 1.0 kg/m2 in BMI was associated with lower incidence of hematoma formation （OR： 0.84; 95% CI： 0.74-0.95;P = 0.006）.ConclusionBMI 〈 23 kg/m2 was associated with a higher incidence of pocket hematoma, requiring re-intervention. The data sup-port that great care must be taken when patients were with a lower BMI received CIEDs implantation.
