2003年,国际临床骨密度学会(ISCD)发布官方立场:世界卫生组织(WHO)骨密度分类标准不仅限定在绝经后妇女中应用,也可以扩展应用于人口总体中。但是,对绝经前女性、男性和非白种人群骨密度分类的应用,这一文件并没有完全诠释清楚。2005年...2003年,国际临床骨密度学会(ISCD)发布官方立场:世界卫生组织(WHO)骨密度分类标准不仅限定在绝经后妇女中应用,也可以扩展应用于人口总体中。但是,对绝经前女性、男性和非白种人群骨密度分类的应用,这一文件并没有完全诠释清楚。2005年召开ISCD共识发展大会,ISCD专家组成员同ISCD专业顾问委员会一起重新讨论了这些主题,并依据严密、可靠、最新的数据资料回顾,进一步准确清晰地从以下方面确定了2005年ISCD官方立场。(1)‘骨量减少’(osteopenia)术语的通用性;(2)骨密度报告中T值和Z值的适用范围;(3)什么年龄范围适用于WHO骨密度分类标准;(4)哪一个正常数据库可适用于非白种人群。概括地说,可以继续使用术语‘骨量减少’(Osteopenia),但应首选‘低骨量’(low bone mass)或‘低骨密度’(low bone density)。对绝经前女性和50岁以下男性,首选Z值(不是T值)。等于或低于-2.0的Z值定义为“低于该年龄预期值范围以下”,大于-2.0以上的Z值则定义为“处于该年龄预期值范围以内”。在绝经后女性和≥50岁男性中,T值首选,适用WHO的分类标准。下面行文将对这些正式立场的理论基础和依据展开讨论。展开更多
The Yangtze River Watershed in China is a climate change hotspot featuring strong spatial and temporal variability;hence, it poses a certain threat to social development. Identifying the characteristics of and regions...The Yangtze River Watershed in China is a climate change hotspot featuring strong spatial and temporal variability;hence, it poses a certain threat to social development. Identifying the characteristics of and regions vulnerable to climate change is significantly important for formulating adaptive countermeasures. However, with regard to the Yangtze River Watershed, there is currently a lack of research on these aspects from the perspective of natural and anthropogenic factors. To address this issue, in this study, based on the temperature and precipitation records from 717 meteorological stations, the RClim Dex and random forest models were used to assess the spatiotemporal characteristics of climate change and identify mainly the natural and anthropogenic factors influencing climate change hotspots in the Yangtze River Watershed for the period 1958-2017. The results indicated a significant increasing trend in temperature, a trend of wet and dry polarization in the annual precipitation, and that the number of temperature indices with significant variations was 2.8 times greater than that of precipitation indices. Significant differences were also noted in the responses of the climate change characteristics of the sub-basins to anthropogenic and natural factors;the delta plain of the Yangtze River estuary exhibited the most significant climate changes, where 88.89% of the extreme climate indices varied considerably. Furthermore, the characteristics that were similar among the identified hotpots, including human activities(higher Gross Domestic Product and construction land proportions) and natural factors(high altitudes and large proportions of grassland and water bodies), were positively correlated with the rapid climate warming.展开更多
文摘2003年,国际临床骨密度学会(ISCD)发布官方立场:世界卫生组织(WHO)骨密度分类标准不仅限定在绝经后妇女中应用,也可以扩展应用于人口总体中。但是,对绝经前女性、男性和非白种人群骨密度分类的应用,这一文件并没有完全诠释清楚。2005年召开ISCD共识发展大会,ISCD专家组成员同ISCD专业顾问委员会一起重新讨论了这些主题,并依据严密、可靠、最新的数据资料回顾,进一步准确清晰地从以下方面确定了2005年ISCD官方立场。(1)‘骨量减少’(osteopenia)术语的通用性;(2)骨密度报告中T值和Z值的适用范围;(3)什么年龄范围适用于WHO骨密度分类标准;(4)哪一个正常数据库可适用于非白种人群。概括地说,可以继续使用术语‘骨量减少’(Osteopenia),但应首选‘低骨量’(low bone mass)或‘低骨密度’(low bone density)。对绝经前女性和50岁以下男性,首选Z值(不是T值)。等于或低于-2.0的Z值定义为“低于该年龄预期值范围以下”,大于-2.0以上的Z值则定义为“处于该年龄预期值范围以内”。在绝经后女性和≥50岁男性中,T值首选,适用WHO的分类标准。下面行文将对这些正式立场的理论基础和依据展开讨论。
基金Program for Guangdong Introducing Innovative and Entrepreneurial Teams,No.2019ZT08L213National Natural Science Foundation of China,No.41701631+1 种基金Guangdong Provincial Key Laboratory Project,No.2019B121203011Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou),No.GML2019ZD0403。
文摘The Yangtze River Watershed in China is a climate change hotspot featuring strong spatial and temporal variability;hence, it poses a certain threat to social development. Identifying the characteristics of and regions vulnerable to climate change is significantly important for formulating adaptive countermeasures. However, with regard to the Yangtze River Watershed, there is currently a lack of research on these aspects from the perspective of natural and anthropogenic factors. To address this issue, in this study, based on the temperature and precipitation records from 717 meteorological stations, the RClim Dex and random forest models were used to assess the spatiotemporal characteristics of climate change and identify mainly the natural and anthropogenic factors influencing climate change hotspots in the Yangtze River Watershed for the period 1958-2017. The results indicated a significant increasing trend in temperature, a trend of wet and dry polarization in the annual precipitation, and that the number of temperature indices with significant variations was 2.8 times greater than that of precipitation indices. Significant differences were also noted in the responses of the climate change characteristics of the sub-basins to anthropogenic and natural factors;the delta plain of the Yangtze River estuary exhibited the most significant climate changes, where 88.89% of the extreme climate indices varied considerably. Furthermore, the characteristics that were similar among the identified hotpots, including human activities(higher Gross Domestic Product and construction land proportions) and natural factors(high altitudes and large proportions of grassland and water bodies), were positively correlated with the rapid climate warming.
