The spatial form of urbanization in China has developed from single-core city expansion to a multi-center metropolitan area.However,little attention has been paid to the growth process of the emerging metropolitan are...The spatial form of urbanization in China has developed from single-core city expansion to a multi-center metropolitan area.However,little attention has been paid to the growth process of the emerging metropolitan area situated in major grain producing locations in the central China.Taking the Zhengzhou metropolitan area(ZZMA)as a case study,we developed an inverse S-shape model to characterize the spatial distribution of urban land density,and constructed an urban expansion core index,urban expansion intensity index,and urban compactness index to quantify the spatial structure change that has taken place from 1978 to 2017 during the process of urban expansion.Moreover,cropland contribution rate(CR)was constructed to evaluate the impacts of urban expansion on croplands.We uncovered four key findings.First,over the past 40 yr,the ZZMA has experienced dramatic expansion,and the central city of Zhengzhou expanded faster than other cities.The gravity centers of urban expansion of surrounding cities were moving toward to Zhengzhou City.Second,the urban land density decreased with the distance from the city center to the outskirts.As the only large city,Zhengzhou has experienced the fastest and most compact centralized urban expansion,especially after 2000,while other medium-and small-sized cities have experienced low-intensity decentralized expansion.Third,the urban core has been gradually expanding outward.From 1978 to 2017,the hot-zone of urban growth has moved progressively with the acceleration of urbanization.All cities except Jiaozuo had a single peak in different periods.Forth,the cities in national core grain-producing areas has higher cropland contribution rates and lower urban expansion areas,which was closely related to cropland protection.Further analysis showed that large city was relatively better positioned than smaller cities in the efficiency of their urban infrastructure and the effectiveness of wealth creation efficiency in the urbanized area could be tested in all cities,and the policy factor seemed to play an important role in the urban expansion process.展开更多
目的了解湖北省南部地区农村居民慢性阻塞性肺疾病（Chronic obstructive pul monary disease,COPD）患病率及危险因素,为防治慢性阻塞性肺疾病提供科学依据。方法采用统一的流行病学调查表,以多阶段抽样方法,抽取湖北省南部地区农村居...目的了解湖北省南部地区农村居民慢性阻塞性肺疾病（Chronic obstructive pul monary disease,COPD）患病率及危险因素,为防治慢性阻塞性肺疾病提供科学依据。方法采用统一的流行病学调查表,以多阶段抽样方法,抽取湖北省南部地区农村居民1883人进行调查,并进行体检和肺功能检测,对慢性阻塞性肺疾病的危险因素进行单因素和多因素Logistic分析。结果共检出慢性阻塞性肺疾病患者186例,总患病率为9.88%,其中男性为13.68%,女性6.46%,男性高于女性（χ^2=27.48,P〈0.001）;随年龄增高患病率逐渐上升（χ^2=79.22,P〈0.001）。多因素分析表明,性别（OR=1.3010,95%CI=1.0408～1.6260,P=0.021）、年龄（OR=1.8506,95%CI=1.0419～3.2870,P=0.036）、吸烟（OR=3.0118,95%CI=1.5523～5.8443,P=0.000）、做饭频率（OR=1.7651,95%CI=1.1036～2.8230,P=0.018）、家族史（OR=1.5278,95%CI=1.1507～2.0283,P=0.003）、14岁以前经常咳嗽（OR=2.8965,95%CI=1.1301～7.4238,P=0.026）为慢性阻塞性肺疾病的危险因素。结论湖北省南部农村慢性阻塞性肺疾病患病率较高,应针对危险因素采取综合干预措施降低发病率。展开更多
基金Under the auspices of National Natural Science Foundation of China(No.41971274)the Innovation Research Team of Henan Provincial University(No.2021-CXTD-08,2022-CXTD-02)the Scientific and Technological Innovation Team of Universities in Henan Province(No.22IRTSTHN008)。
文摘The spatial form of urbanization in China has developed from single-core city expansion to a multi-center metropolitan area.However,little attention has been paid to the growth process of the emerging metropolitan area situated in major grain producing locations in the central China.Taking the Zhengzhou metropolitan area(ZZMA)as a case study,we developed an inverse S-shape model to characterize the spatial distribution of urban land density,and constructed an urban expansion core index,urban expansion intensity index,and urban compactness index to quantify the spatial structure change that has taken place from 1978 to 2017 during the process of urban expansion.Moreover,cropland contribution rate(CR)was constructed to evaluate the impacts of urban expansion on croplands.We uncovered four key findings.First,over the past 40 yr,the ZZMA has experienced dramatic expansion,and the central city of Zhengzhou expanded faster than other cities.The gravity centers of urban expansion of surrounding cities were moving toward to Zhengzhou City.Second,the urban land density decreased with the distance from the city center to the outskirts.As the only large city,Zhengzhou has experienced the fastest and most compact centralized urban expansion,especially after 2000,while other medium-and small-sized cities have experienced low-intensity decentralized expansion.Third,the urban core has been gradually expanding outward.From 1978 to 2017,the hot-zone of urban growth has moved progressively with the acceleration of urbanization.All cities except Jiaozuo had a single peak in different periods.Forth,the cities in national core grain-producing areas has higher cropland contribution rates and lower urban expansion areas,which was closely related to cropland protection.Further analysis showed that large city was relatively better positioned than smaller cities in the efficiency of their urban infrastructure and the effectiveness of wealth creation efficiency in the urbanized area could be tested in all cities,and the policy factor seemed to play an important role in the urban expansion process.
文摘目的了解湖北省南部地区农村居民慢性阻塞性肺疾病（Chronic obstructive pul monary disease,COPD）患病率及危险因素,为防治慢性阻塞性肺疾病提供科学依据。方法采用统一的流行病学调查表,以多阶段抽样方法,抽取湖北省南部地区农村居民1883人进行调查,并进行体检和肺功能检测,对慢性阻塞性肺疾病的危险因素进行单因素和多因素Logistic分析。结果共检出慢性阻塞性肺疾病患者186例,总患病率为9.88%,其中男性为13.68%,女性6.46%,男性高于女性（χ^2=27.48,P〈0.001）;随年龄增高患病率逐渐上升（χ^2=79.22,P〈0.001）。多因素分析表明,性别（OR=1.3010,95%CI=1.0408～1.6260,P=0.021）、年龄（OR=1.8506,95%CI=1.0419～3.2870,P=0.036）、吸烟（OR=3.0118,95%CI=1.5523～5.8443,P=0.000）、做饭频率（OR=1.7651,95%CI=1.1036～2.8230,P=0.018）、家族史（OR=1.5278,95%CI=1.1507～2.0283,P=0.003）、14岁以前经常咳嗽（OR=2.8965,95%CI=1.1301～7.4238,P=0.026）为慢性阻塞性肺疾病的危险因素。结论湖北省南部农村慢性阻塞性肺疾病患病率较高,应针对危险因素采取综合干预措施降低发病率。
