Equal access to social infrastructures is a fundamental prerequisite for sustainable development,but has long been a great challenge worldwide.Previous studies have primarily focused on the accessibility to social inf...Equal access to social infrastructures is a fundamental prerequisite for sustainable development,but has long been a great challenge worldwide.Previous studies have primarily focused on the accessibility to social infras-tructures in urban areas across various scales,with less attention to rural areas,where inequality can be more severe.Particularly,few have investigated the disparities of accessibility to social infrastructures between urban and rural areas.Here,using the Changsha-Zhuzhou-Xiangtan urban agglomeration,China,as an example,we investigated the inequality of accessibility in both urban and rural areas,and further compared the urban-rural difference.Accessibility was measured by travel time of residents to infrastructures.We selected four types of social infrastructures including supermarkets,bus stops,primary schools,and health care,which were funda-mentally important to both urban and rural residents.We found large disparities in accessibility between urban and rural areas,ranging from 20 min to 2 h.Rural residents had to spend one to two more hours to bus stops than urban residents,and 20 min more to the other three types of infrastructures.Furthermore,accessibility to multiple infrastructures showed greater urban-rural differences.Rural residents in more than half of the towns had no access to any infrastructure within 15 min,while more than 60%of the urban residents could access to all infrastructures within 15 min.Our results revealed quantitative accessibility gap between urban and rural areas and underscored the necessity of social infrastructures planning to address such disparities.展开更多
Invariant measures of Markov chains in discrete or continuous time with a countable set of states are characterized by its steady state recurrence relations. Exemplarily, we consider transition matrices and Q-matrices...Invariant measures of Markov chains in discrete or continuous time with a countable set of states are characterized by its steady state recurrence relations. Exemplarily, we consider transition matrices and Q-matrices with upper bandwidth n and lower bandwidth 1 where the invariant measures satisfy an (n + 1)-order linear difference equation. Markov chains of this type arise from applications to queueing problems and population dynamics. It is the purpose of this paper to point out that the forward use of this difference equation is subject to some hitherto unobserved aspects. By means of the concept of generalized continued fractions (GCFs), we prove that each invariant measure is a dominated solution of the difference equation such that forward computation becomes numerically unstable. Furthermore, the GCF-based approach provides a decoupled recursion in which the phenomenon of numerical instability does not appear. The procedure results in an iteration scheme for successively computing approximants of the desired invariant measure depending on some truncation level N. Increasing N leads to the desired solution. A comparison study of forward computation and the GCF-based approach is given for Q-matrices with upper bandwidth 1 and 2.展开更多
Uneven urban and rural development is one of the main reasons for the decline of the countryside.This imbalance could be measured by the urban-rural difference index(URDI).Existing studies on urban-rural differences h...Uneven urban and rural development is one of the main reasons for the decline of the countryside.This imbalance could be measured by the urban-rural difference index(URDI).Existing studies on urban-rural differences have focused on single dimension between urban and rural areas,and lack a systematic multi-dimensional measurement.Based on the construction of an index system and model for measuring urban-rural differences,this study took the Huang-Huai-Hai Plain(HHHP)as the study area,explores the spatial pattern of urban-rural differences in the area,and used geographical weighted regression models to identify the factors affecting urban-rural development differences.Results show that the mean value of URDI in the HHHP was 0.295,and the URDI in its western region was higher than that in the east.The average URDI was relatively high in the western counties along the Beijing–Guangzhou Railway.The low level of urban-rural'population-land-industry'development in the HHHP is an important reason for the small differences between urban and rural areas.Improvements in road transportation infrastructure have led to an increase in the urban-rural development gap.However,the driving force of the road network on urban development is greater than that on rural areas.The role of county economic agglomeration is gaining strength.In the process of rapid economic development,more attention should be paid to the development of the rural economy and the overall revitalization of the countryside.The equivalent allocation of social service facilities is an effective way to solve the problem of urban-rural imbalance.Further analysis demonstrated that terrain factors have relatively little influence on the URDI.This study provides a new perspective and measurement method for understanding the integration of urban and rural development,and provides a useful reference for guiding the urban-rural integration development and the rural revitalization.展开更多
AIM: To study the salient features of colorectal cancer(CRC) in Libya.METHODS: Patients records were gathered at the primary oncology clinic in eastern Libya for the period of one calendar year(2012). Using this data,...AIM: To study the salient features of colorectal cancer(CRC) in Libya.METHODS: Patients records were gathered at the primary oncology clinic in eastern Libya for the period of one calendar year(2012). Using this data, various parameters were analyzed and age-standardized incidence rates were determined using the direct method and the standard population.RESULTS: During 2012, 174 patients were diagnosed with CRC, 51.7%(n = 90) male and 48.3%(n = 84) females. The average age was 58.7(± 13.4) years, with men around 57.3(± 13) years old and women usually 60.1(± 13.8) years of age. Libya has the highest rate of CRC in North Africa, with an incidence closer to the European figures. The age-standardized rate for CRC was 17.5 and 17.2/100000 for males and females respectively. It was the second most common cancer, forming 19% of malignancies, with fluctuation in ranking and incidence in different cities/villages. Increasingly, younger ages are being afflicted and a higher proportion of patients are among the > 40 years subset.Nearly two-thirds presented at either stage Ⅲ(22.4%) or Ⅳ(38.4%).CONCLUSION: Cancer surveillance systems should be established in order to effectively monitor the situation. Likewise, screening programs are invaluable in the Libyan scenario given the predominance of sporadic cases.展开更多
Based on three datasets of the Chinese Social Survey(CSS)2013,2015,and 2017 and the National Statistical Yearbook,this study examined whether and in what ways using the Internet may or may not affect the public evalua...Based on three datasets of the Chinese Social Survey(CSS)2013,2015,and 2017 and the National Statistical Yearbook,this study examined whether and in what ways using the Internet may or may not affect the public evaluation of government environmental governance(GEG).There are three main findings.First,Internet use has a negative influence on the public evaluation of GEG.Second,there has been an urban-rural difference in terms of Internet use;especially for the rural resident,increasing their use of the Internet significantly lowered their evaluation of GEG.Third,Internet use affects GEG mainly through political trust,whilst it tends to enhance people’s perception of environmental problems;however,it has little influence on their evaluation of GEG.This finding implies that public evaluation of GEG should be viewed as an important inter-subjective dimension of GEG;especially in the Internet era,it has become increasingly necessary for the government to not only continuously improve the quality of governance by dealing with actual/practical environmental issues,but also enhance its ability to react to the public opinions online effectively and appropriately.展开更多
针对水轮发电机组振动信号呈现为非平稳、非线性且易受周围环境噪声影响导致机组振动信号特征难以准确提取的问题,提出固有时间尺度分解(Intrinsic time scale decomposition,ITD)结合模糊熵(fuzzy entropy,FE)奇异值差分谱(singular va...针对水轮发电机组振动信号呈现为非平稳、非线性且易受周围环境噪声影响导致机组振动信号特征难以准确提取的问题,提出固有时间尺度分解(Intrinsic time scale decomposition,ITD)结合模糊熵(fuzzy entropy,FE)奇异值差分谱(singular value decomposition,SVD)的水轮发电机组振动信号去噪方法。利用ITD先对振动数据进行分解以模糊熵为阈值,选取模糊熵值小于2的分量进行重构,达到第一次去噪的效果。再在这个去噪的基础上进行SVD分解,根据奇异值差分谱中奇异值变化较大的点来选择重构阶数对数据进行重构,从而达到几乎完全去噪的效果。最后将本方法和局部均值分解(LMD)结合模糊熵和奇异值差分谱的方法进行对比发现,ITD-FE-SVD去噪效果更好,能够保留更多的原信号信息。展开更多
基金supported by funding from the National Natural Science Foundation of China(Grant No.U21A2010)the National Science Fund for Distinguished Young Scholars(Grant No.42225104)the National Key Research and Development Program(Grant No.2022YFF130110O).
文摘Equal access to social infrastructures is a fundamental prerequisite for sustainable development,but has long been a great challenge worldwide.Previous studies have primarily focused on the accessibility to social infras-tructures in urban areas across various scales,with less attention to rural areas,where inequality can be more severe.Particularly,few have investigated the disparities of accessibility to social infrastructures between urban and rural areas.Here,using the Changsha-Zhuzhou-Xiangtan urban agglomeration,China,as an example,we investigated the inequality of accessibility in both urban and rural areas,and further compared the urban-rural difference.Accessibility was measured by travel time of residents to infrastructures.We selected four types of social infrastructures including supermarkets,bus stops,primary schools,and health care,which were funda-mentally important to both urban and rural residents.We found large disparities in accessibility between urban and rural areas,ranging from 20 min to 2 h.Rural residents had to spend one to two more hours to bus stops than urban residents,and 20 min more to the other three types of infrastructures.Furthermore,accessibility to multiple infrastructures showed greater urban-rural differences.Rural residents in more than half of the towns had no access to any infrastructure within 15 min,while more than 60%of the urban residents could access to all infrastructures within 15 min.Our results revealed quantitative accessibility gap between urban and rural areas and underscored the necessity of social infrastructures planning to address such disparities.
文摘Invariant measures of Markov chains in discrete or continuous time with a countable set of states are characterized by its steady state recurrence relations. Exemplarily, we consider transition matrices and Q-matrices with upper bandwidth n and lower bandwidth 1 where the invariant measures satisfy an (n + 1)-order linear difference equation. Markov chains of this type arise from applications to queueing problems and population dynamics. It is the purpose of this paper to point out that the forward use of this difference equation is subject to some hitherto unobserved aspects. By means of the concept of generalized continued fractions (GCFs), we prove that each invariant measure is a dominated solution of the difference equation such that forward computation becomes numerically unstable. Furthermore, the GCF-based approach provides a decoupled recursion in which the phenomenon of numerical instability does not appear. The procedure results in an iteration scheme for successively computing approximants of the desired invariant measure depending on some truncation level N. Increasing N leads to the desired solution. A comparison study of forward computation and the GCF-based approach is given for Q-matrices with upper bandwidth 1 and 2.
基金National Key Research and Development Program,No.2017YFC0504701Major Project of National Social Science Foundation of China,No.15ZDA021China Postdoctoral Science Foundation,No.2016M591105。
文摘Uneven urban and rural development is one of the main reasons for the decline of the countryside.This imbalance could be measured by the urban-rural difference index(URDI).Existing studies on urban-rural differences have focused on single dimension between urban and rural areas,and lack a systematic multi-dimensional measurement.Based on the construction of an index system and model for measuring urban-rural differences,this study took the Huang-Huai-Hai Plain(HHHP)as the study area,explores the spatial pattern of urban-rural differences in the area,and used geographical weighted regression models to identify the factors affecting urban-rural development differences.Results show that the mean value of URDI in the HHHP was 0.295,and the URDI in its western region was higher than that in the east.The average URDI was relatively high in the western counties along the Beijing–Guangzhou Railway.The low level of urban-rural'population-land-industry'development in the HHHP is an important reason for the small differences between urban and rural areas.Improvements in road transportation infrastructure have led to an increase in the urban-rural development gap.However,the driving force of the road network on urban development is greater than that on rural areas.The role of county economic agglomeration is gaining strength.In the process of rapid economic development,more attention should be paid to the development of the rural economy and the overall revitalization of the countryside.The equivalent allocation of social service facilities is an effective way to solve the problem of urban-rural imbalance.Further analysis demonstrated that terrain factors have relatively little influence on the URDI.This study provides a new perspective and measurement method for understanding the integration of urban and rural development,and provides a useful reference for guiding the urban-rural integration development and the rural revitalization.
文摘AIM: To study the salient features of colorectal cancer(CRC) in Libya.METHODS: Patients records were gathered at the primary oncology clinic in eastern Libya for the period of one calendar year(2012). Using this data, various parameters were analyzed and age-standardized incidence rates were determined using the direct method and the standard population.RESULTS: During 2012, 174 patients were diagnosed with CRC, 51.7%(n = 90) male and 48.3%(n = 84) females. The average age was 58.7(± 13.4) years, with men around 57.3(± 13) years old and women usually 60.1(± 13.8) years of age. Libya has the highest rate of CRC in North Africa, with an incidence closer to the European figures. The age-standardized rate for CRC was 17.5 and 17.2/100000 for males and females respectively. It was the second most common cancer, forming 19% of malignancies, with fluctuation in ranking and incidence in different cities/villages. Increasingly, younger ages are being afflicted and a higher proportion of patients are among the > 40 years subset.Nearly two-thirds presented at either stage Ⅲ(22.4%) or Ⅳ(38.4%).CONCLUSION: Cancer surveillance systems should be established in order to effectively monitor the situation. Likewise, screening programs are invaluable in the Libyan scenario given the predominance of sporadic cases.
基金supported by Major Project of The National Social Science Fund of China[Grant number.19ZDA149]the Guanghua Talent Project of Southwestern University of Finance and Economics.
文摘Based on three datasets of the Chinese Social Survey(CSS)2013,2015,and 2017 and the National Statistical Yearbook,this study examined whether and in what ways using the Internet may or may not affect the public evaluation of government environmental governance(GEG).There are three main findings.First,Internet use has a negative influence on the public evaluation of GEG.Second,there has been an urban-rural difference in terms of Internet use;especially for the rural resident,increasing their use of the Internet significantly lowered their evaluation of GEG.Third,Internet use affects GEG mainly through political trust,whilst it tends to enhance people’s perception of environmental problems;however,it has little influence on their evaluation of GEG.This finding implies that public evaluation of GEG should be viewed as an important inter-subjective dimension of GEG;especially in the Internet era,it has become increasingly necessary for the government to not only continuously improve the quality of governance by dealing with actual/practical environmental issues,but also enhance its ability to react to the public opinions online effectively and appropriately.
文摘针对水轮发电机组振动信号呈现为非平稳、非线性且易受周围环境噪声影响导致机组振动信号特征难以准确提取的问题,提出固有时间尺度分解(Intrinsic time scale decomposition,ITD)结合模糊熵(fuzzy entropy,FE)奇异值差分谱(singular value decomposition,SVD)的水轮发电机组振动信号去噪方法。利用ITD先对振动数据进行分解以模糊熵为阈值,选取模糊熵值小于2的分量进行重构,达到第一次去噪的效果。再在这个去噪的基础上进行SVD分解,根据奇异值差分谱中奇异值变化较大的点来选择重构阶数对数据进行重构,从而达到几乎完全去噪的效果。最后将本方法和局部均值分解(LMD)结合模糊熵和奇异值差分谱的方法进行对比发现,ITD-FE-SVD去噪效果更好,能够保留更多的原信号信息。
