The spatial genetic structure is a topical issue in the studies of various aspects of ecology and evolution.Using the multilocus autocorrelation method with hypervariable microsatellite genetic markers,we investigated...The spatial genetic structure is a topical issue in the studies of various aspects of ecology and evolution.Using the multilocus autocorrelation method with hypervariable microsatellite genetic markers,we investigated afine-scale pattern of genetic structure in 5 local populations of the common shrew Sorex araneus separated by distances of 300–1000 m(the Moscow chromosomal race).Spatial genetic autocorrelation analysis based on 5 microsatellite loci(expected heterozygosity>0.79)with 90 alleles revealed a consistent pattern of significant positive genetic structure.By testing the autocorrelation at multiple scales from 25 to 500 m,we found that positive spatial genetic structure is detectable in distance classes of<500 m.The weaker spatial genetic structure positively correlated with a higher ratio of nonresident individuals to residents’activity(number of captures).In contrast to nonresident animals,the residents demonstrated prominent genetic structure.Genetic difference(FST)between the populations was significant(0.016–0.051)and comparable with that between populations of different races analyzed previously(0.016–0.038).FST was not associated with geographic distance.These demographic patterns allowed us to propose a scheme of genetic-structure dynamics involving periodic appearance of more related local groups and renewal of allelic profiles fromаcommon pool where the alleles are mixed.The scheme predictsfluctuating genetic structure and random similar differences among local populations.展开更多
The Second Demographic Transition(SDT)is a useful theoretical framework for explaining the recent trend in many countries of very low fertility combined with alternative union and family types.Although past studies ha...The Second Demographic Transition(SDT)is a useful theoretical framework for explaining the recent trend in many countries of very low fertility combined with alternative union and family types.Although past studies have observed the SDT in many Western societies,whether it is applicable to East Asia remains unclear.Capitalizing on data from the Chinese Census and China Family Panel Studies,we provide estimates of key behavioral and ideational indicators of the SDT.We find that union formation in China has trended increasingly toward patterns commonly observed in the West,including delayed age of marriage and the common practice of premarital cohabitation.While having a lowest-low fertility rate,China has not experienced rising nonmarital childbirths,a key component of the SDT.However,we observe growing tolerance toward nonmarital childbearing and childlessness.Marriages remain relatively stable in China,especially among couples with children.Taken together,our analysis suggests that typically coincident changes in patterns of family behavior associated with the SDT are not occurring simultaneously in China.Moreover,ideational changes are preceding behavioral changes,particularly in attitudes toward nonmarital childbearing and childlessness.Our research suggests a different pattern of the SDT in China,which has been heavily influenced by Confucian culture.展开更多
Background:Dengue fever(DF)outbreaks present regionally specific epidemiological and clinical characteristics.In certain medium-sized cities(100000–250000 inhabitants)of São Paulo State,Brazil,and after reaching...Background:Dengue fever(DF)outbreaks present regionally specific epidemiological and clinical characteristics.In certain medium-sized cities(100000–250000 inhabitants)of São Paulo State,Brazil,and after reaching an incidence of 150 cases/100000 inhabitants(“epidemiological threshold”),clinical diagnosis indicated dengue virus(DENV)infection.During this period,other seasonally infectious diseases with symptoms and physical signs mimicking DF can simultaneously occur,with the consequential overcrowding of health care facilities as the principal drawbacks.Confirmation of clinical diagnosis of DF with serological tests may help in avoiding faulty diagnosis in patients,who might later undergo dengue hemorrhagic fever(DHF)and the dengue-shock syndrome(DSS).Furthermore,demographic and hematological profiles of patients are useful in detecting specific early characteristics associated to DF,DHF and DSS.Methods:From March to June,2007,456 patients from Marilia in northwest São Paulo State who had only been diagnosed for DF by clinical criteria,underwent serologic testing for non-structural 1(NS1)DENV antigens.Individual results were used in comparative analysis according to demographic(gender,age)and hematological(leukocyte and platelet counts,percentage of atypical lymphocytes)profiles.Temporal patterns were evaluated by subdividing data according to time of initial attendance,using recorded variables as predictors of DENV infection in logistic regression models and ROC curves.Results:Serologic DENV detection was positive in 70.6%of the patients.Lower leukocyte and platelet counts were the most important factors in predicting DENV infection(respective medians DENV+=3715 cells/ml and DENV-=6760 cells/ml,and DENV+=134896 cells/ml and DENV-=223872 cells/ml).Furthermore,all demographic and hematological profiles presented a conservative temporal pattern throughout this long-lasting outbreak.Conclusions:As consistency throughout the epidemic facilitated defining the conservation pattern throughout the early stages,thi展开更多
Introduction:Exotic invasive species represent a major driver of the loss of biological diversity and services provided by ecosystems globally.An important cause of species becoming invasive is the development of comm...Introduction:Exotic invasive species represent a major driver of the loss of biological diversity and services provided by ecosystems globally.An important cause of species becoming invasive is the development of commercial afforestation projects using fast-growing and adaptable exotic species,which may become invasive impacting natural environments.The tropical ash(Fraxinus uhdei),native to México,has been widely introduced to Colombia and other countries for timber,live fences,and urban greening.It is now common in many areas of the tropical mountains and has been observed expanding into native forests in Colombia.This study examined the invasion pattern and the demographic structure of tropical ash in remnant Andean forests in Colombia,to find out factors associated with the invasion process.The analysis took into account biotic and physical factors:distance to propagule source,vegetation cover types,and understory and canopy cover.Results:Although the reproductive strategy of the tropical ash is of“r”type with low survival rates,the results show evidence for an active process of invasion characterized by an aggregated distribution pattern dominated by seedlings and juvenile plants.The study shows the existence of an interaction between the distance to propagule source and the vegetation cover,which has an additive effect on the demographic structure of the population.Conclusions:This study suggests an active invasion process by the exotic tree tropical ash into a remnant of sub-humid forests in the Andean highlands.Our results showed an expanding population process with a decreasing average age from propagule sources and mature reproductive individuals within the native forest,which bring new individuals that are colonizing new areas and advancing into the forest.This research points to the need for urgent plant intervention on two aspects:the use of the tropical ash and the management of the invasion process in native forests.展开更多
Based on census data from China,this paper uses SOCSIM microscopic simulation method to decompose the key factors of family transition into demographic and residence pattern factors.The former are further broken down ...Based on census data from China,this paper uses SOCSIM microscopic simulation method to decompose the key factors of family transition into demographic and residence pattern factors.The former are further broken down into demographic inertia,fertility,mortality and marriage rate.The results indicate that the current demographic changes are relatively small and,thus,the small fluctuations caused by demographic changes contribute much less than residence pattern to the family transition.Among the demographic factors,demographic inertia and fertility have a greater effect on family transition and the impacts caused by fertility and marriage rate are consistent with the direction of the overall influence of demographic factors:increasing the proportion of single-person households,one-generation households,and two-generation households,and decreasing the proportion of three-generation or more households.In contrast,the effect of mortality rate was opposite to that of fertility rate,which increased the proportion of populations living in single-person,one-generation,and two-generation households,but the decreased the proportion of the population living in three-generation or more households.展开更多
This Paper, taking Nanhai City of Guangdong Province as an example, focuses on five interrelated aspects of the migrant labour force of China in recent year’s. Attention is initially paid to the background of the lab...This Paper, taking Nanhai City of Guangdong Province as an example, focuses on five interrelated aspects of the migrant labour force of China in recent year’s. Attention is initially paid to the background of the labour migration from inland towards coastal area. Then, the demographic characteristics of the migrant labour force are analysed before turning to the analysis on the rare for the migration. Fourthly, the impacts of the migrant workers on the socio-economic development of Nanhai City and the problems are examined. Finally, the prospects and some suggestions for the labour migration are put forward.展开更多
基金supported by Russian Foundation for Basic Research grant no.19-04-00985_a(to S.V.P.).
文摘The spatial genetic structure is a topical issue in the studies of various aspects of ecology and evolution.Using the multilocus autocorrelation method with hypervariable microsatellite genetic markers,we investigated afine-scale pattern of genetic structure in 5 local populations of the common shrew Sorex araneus separated by distances of 300–1000 m(the Moscow chromosomal race).Spatial genetic autocorrelation analysis based on 5 microsatellite loci(expected heterozygosity>0.79)with 90 alleles revealed a consistent pattern of significant positive genetic structure.By testing the autocorrelation at multiple scales from 25 to 500 m,we found that positive spatial genetic structure is detectable in distance classes of<500 m.The weaker spatial genetic structure positively correlated with a higher ratio of nonresident individuals to residents’activity(number of captures).In contrast to nonresident animals,the residents demonstrated prominent genetic structure.Genetic difference(FST)between the populations was significant(0.016–0.051)and comparable with that between populations of different races analyzed previously(0.016–0.038).FST was not associated with geographic distance.These demographic patterns allowed us to propose a scheme of genetic-structure dynamics involving periodic appearance of more related local groups and renewal of allelic profiles fromаcommon pool where the alleles are mixed.The scheme predictsfluctuating genetic structure and random similar differences among local populations.
文摘The Second Demographic Transition(SDT)is a useful theoretical framework for explaining the recent trend in many countries of very low fertility combined with alternative union and family types.Although past studies have observed the SDT in many Western societies,whether it is applicable to East Asia remains unclear.Capitalizing on data from the Chinese Census and China Family Panel Studies,we provide estimates of key behavioral and ideational indicators of the SDT.We find that union formation in China has trended increasingly toward patterns commonly observed in the West,including delayed age of marriage and the common practice of premarital cohabitation.While having a lowest-low fertility rate,China has not experienced rising nonmarital childbirths,a key component of the SDT.However,we observe growing tolerance toward nonmarital childbearing and childlessness.Marriages remain relatively stable in China,especially among couples with children.Taken together,our analysis suggests that typically coincident changes in patterns of family behavior associated with the SDT are not occurring simultaneously in China.Moreover,ideational changes are preceding behavioral changes,particularly in attitudes toward nonmarital childbearing and childlessness.Our research suggests a different pattern of the SDT in China,which has been heavily influenced by Confucian culture.
基金This study received financial support from PRONEX/Dengue,CNPq,Grant number 550106/2010-3.
文摘Background:Dengue fever(DF)outbreaks present regionally specific epidemiological and clinical characteristics.In certain medium-sized cities(100000–250000 inhabitants)of São Paulo State,Brazil,and after reaching an incidence of 150 cases/100000 inhabitants(“epidemiological threshold”),clinical diagnosis indicated dengue virus(DENV)infection.During this period,other seasonally infectious diseases with symptoms and physical signs mimicking DF can simultaneously occur,with the consequential overcrowding of health care facilities as the principal drawbacks.Confirmation of clinical diagnosis of DF with serological tests may help in avoiding faulty diagnosis in patients,who might later undergo dengue hemorrhagic fever(DHF)and the dengue-shock syndrome(DSS).Furthermore,demographic and hematological profiles of patients are useful in detecting specific early characteristics associated to DF,DHF and DSS.Methods:From March to June,2007,456 patients from Marilia in northwest São Paulo State who had only been diagnosed for DF by clinical criteria,underwent serologic testing for non-structural 1(NS1)DENV antigens.Individual results were used in comparative analysis according to demographic(gender,age)and hematological(leukocyte and platelet counts,percentage of atypical lymphocytes)profiles.Temporal patterns were evaluated by subdividing data according to time of initial attendance,using recorded variables as predictors of DENV infection in logistic regression models and ROC curves.Results:Serologic DENV detection was positive in 70.6%of the patients.Lower leukocyte and platelet counts were the most important factors in predicting DENV infection(respective medians DENV+=3715 cells/ml and DENV-=6760 cells/ml,and DENV+=134896 cells/ml and DENV-=223872 cells/ml).Furthermore,all demographic and hematological profiles presented a conservative temporal pattern throughout this long-lasting outbreak.Conclusions:As consistency throughout the epidemic facilitated defining the conservation pattern throughout the early stages,thi
文摘Introduction:Exotic invasive species represent a major driver of the loss of biological diversity and services provided by ecosystems globally.An important cause of species becoming invasive is the development of commercial afforestation projects using fast-growing and adaptable exotic species,which may become invasive impacting natural environments.The tropical ash(Fraxinus uhdei),native to México,has been widely introduced to Colombia and other countries for timber,live fences,and urban greening.It is now common in many areas of the tropical mountains and has been observed expanding into native forests in Colombia.This study examined the invasion pattern and the demographic structure of tropical ash in remnant Andean forests in Colombia,to find out factors associated with the invasion process.The analysis took into account biotic and physical factors:distance to propagule source,vegetation cover types,and understory and canopy cover.Results:Although the reproductive strategy of the tropical ash is of“r”type with low survival rates,the results show evidence for an active process of invasion characterized by an aggregated distribution pattern dominated by seedlings and juvenile plants.The study shows the existence of an interaction between the distance to propagule source and the vegetation cover,which has an additive effect on the demographic structure of the population.Conclusions:This study suggests an active invasion process by the exotic tree tropical ash into a remnant of sub-humid forests in the Andean highlands.Our results showed an expanding population process with a decreasing average age from propagule sources and mature reproductive individuals within the native forest,which bring new individuals that are colonizing new areas and advancing into the forest.This research points to the need for urgent plant intervention on two aspects:the use of the tropical ash and the management of the invasion process in native forests.
文摘Based on census data from China,this paper uses SOCSIM microscopic simulation method to decompose the key factors of family transition into demographic and residence pattern factors.The former are further broken down into demographic inertia,fertility,mortality and marriage rate.The results indicate that the current demographic changes are relatively small and,thus,the small fluctuations caused by demographic changes contribute much less than residence pattern to the family transition.Among the demographic factors,demographic inertia and fertility have a greater effect on family transition and the impacts caused by fertility and marriage rate are consistent with the direction of the overall influence of demographic factors:increasing the proportion of single-person households,one-generation households,and two-generation households,and decreasing the proportion of three-generation or more households.In contrast,the effect of mortality rate was opposite to that of fertility rate,which increased the proportion of populations living in single-person,one-generation,and two-generation households,but the decreased the proportion of the population living in three-generation or more households.
文摘This Paper, taking Nanhai City of Guangdong Province as an example, focuses on five interrelated aspects of the migrant labour force of China in recent year’s. Attention is initially paid to the background of the labour migration from inland towards coastal area. Then, the demographic characteristics of the migrant labour force are analysed before turning to the analysis on the rare for the migration. Fourthly, the impacts of the migrant workers on the socio-economic development of Nanhai City and the problems are examined. Finally, the prospects and some suggestions for the labour migration are put forward.
