Ulcerative colitis(UC)is a chronic disease characterized by diffuse inflammation of the mucosa of the colon and rectum.The hallmark clinical symptom of UC is bloody diarrhea.The clinical course is marked by exacerbati...Ulcerative colitis(UC)is a chronic disease characterized by diffuse inflammation of the mucosa of the colon and rectum.The hallmark clinical symptom of UC is bloody diarrhea.The clinical course is marked by exacerbations and remissions,which may occur spontaneously or in response to treatment changes or intercurrent illnesses.UC is most commonly diagnosed in late adolescence or early adulthood,but it can occur at any age.The incidence of UC has increased worldwide over recent decades,especially in developing nations.In contrast,during this period,therapeutic advances have improved the life expectancy of patients,and there has been a decrease in the mortality rate over time.It is important to emphasize that there is considerable variability in the phenotypic presentation of UC.Within this context,certain clinical and demographic characteristics are useful in identifying patients who tend to have more severe evolution of the disease and a poor prognosis.In this group of patients,better clinical surveillance and more intensive therapy may change the natural course of the disease.The aim of this article was to review the epidemiology and demographic characteristics of UC and the factors that may be associated with its clinical prognosis.展开更多
Nuclear factor kappa B(NF-κB) has an established role in the regulation of innate immunity and inflammation.NF-κB is also involved in critical mechanisms connecting inflammation and cancer development.Recent investi...Nuclear factor kappa B(NF-κB) has an established role in the regulation of innate immunity and inflammation.NF-κB is also involved in critical mechanisms connecting inflammation and cancer development.Recent investigations suggest that the NF-κB signaling cascade may be the central mediator of gastrointestinal malignancies including esophageal,gastric and colorectal cancers.This review will explore NF-κB's function in inflammation-associated gastrointestinal malignancies,highlighting its oncogenic contribution to each step of carcinogenesis.NF-κB's role in the inflammation-to-carcinoma sequence in gastrointestinal malignancies warrants stronger emphasis upon targeting this pathway in achieving greater therapeutic efficacy.展开更多
A significant portion of the national water supply can be attributed to de facto or unplanned potable reuse, though the extent of its contribution is difficult to estimate. Fortunately, the contribution of Water Resou...A significant portion of the national water supply can be attributed to de facto or unplanned potable reuse, though the extent of its contribution is difficult to estimate. Fortunately, the contribution of Water Resource Recovery Facility (WRRF) effluent to waters that supply drinking water treatment plants has been documented by some communities. In the United States (US), among the top 25 most impacted drinking water treatment plants by upstream WRRF, 16% of the influent flow to the drinking water treatment plant under average streamflow and up to 100% under low-flow conditions is WRRF effluent. Currently, the full extent of de facto reuse in the US may be much higher because of population growth. The scenario is no different for Beaufort-Jasper Water and Sewer Authority (BJWSA) in South Carolina, US, with contributions to the Savannah River originating from numerous WRRF and other upstream dischargers. South Carolina coastal utilities such as BJSWA are considering direct and indirect potable reuse options, driven by disposal limitations and challenges. Currently, South Carolina does not have a framework, guidelines, or regulations for reuse, but discussions have started among the regulated community. In addition to understanding the extent of de facto reuse, the state will need to develop standards and best practices to enable future adoption of planned potable reuse solutions to water resources challenges. Such guidance should address human health risk management and technical considerations regarding treatment in addition to other factors, including source control, storage, fail-safe operation, monitoring, non-cost factors, and public acceptance. This study conducted a mapping assessment specific to BJWSA, sampled at four locations on Savannah River, and observed that de facto reuse is approximately 4.6% to 5.9% during low-flow months and is within the range generally observed nationwide. When coupled with evidence that planned potable reuse can improve human health and environmental risks, this practice is 展开更多
Heavy metals in the surface sediments and sediment core from the Xiangshan Bay, a mariculture base on the coast of the East China Sea, were determined by inductively coupled plasma mass spectrometry（ICP–MS） in orde...Heavy metals in the surface sediments and sediment core from the Xiangshan Bay, a mariculture base on the coast of the East China Sea, were determined by inductively coupled plasma mass spectrometry（ICP–MS） in order to evaluate their levels and sources. The results showed that the levels of Cu, Pb, Zn, and Cr in the sediments of the bay have been generally influenced by anthropogenic inputs since the founding of the People’s Republic of China. In particular, Cu and Zn were polluted to some extent, as evidenced by high enrichment factors. Organic matter, grain size, wastewater discharge, and low energy hydrodynamic environment played dominant roles in the heavy metal enrichment in the sediments. The ratio of terrigenous source to marine biogenic deposit of trace metals in the sediments was calculated, revealing that terrigenous inputs were the main source of Cu, Pb, and Zn, while biological pellets contributed much more to the enrichment of Cr and Cd. Considering the influence of biological sources on the enrichment of Cd and Cr, and the fact that the sediment has been polluted by Cu and Zn, the development of mariculture and discharge of wastewater into the Bay should be restricted展开更多
The pathogenesis of rheumatoid arthritis(RA) remains to be completely elucidated so far; however, it is known that proinflammatory cytokines play a pivotal role in the induction of RA. Tumor necrosis factor(TNF-α), i...The pathogenesis of rheumatoid arthritis(RA) remains to be completely elucidated so far; however, it is known that proinflammatory cytokines play a pivotal role in the induction of RA. Tumor necrosis factor(TNF-α), in particular, is considered to play a central role in bone destruction by mediating the abnormal activation of osteoclasts or the production of proteolytic enzymes through direct or indirect mechanisms. The use of TNF-α blocking agents has a significant impact on RA therapy. Anti-TNF-α blocking agents such as infliximab are very effective for treatment of RA, especially for the prevention of articular destruction. We have previously shown that several proteins exhibited extensive changes in their expression after amelioration of RA with infliximab treatment. Among the proteins, connective tissue growth factor(CTGF) has a significantrole for the development of RA. Herein, we review the function of CTGF in the pathogenesis of RA and discuss the possibility of a novel treatment for RA. We propose that CTGF is a potentially novel effector molecule in the pathogenesis of RA. Blocking the CTGF pathways by biological agents may have great beneficial effect in patients with RA.展开更多
Article 471 of the Civil Code of the People’s Republic of China(hereinafter referred to as“the Civil Code”)stipulates that contracts may be formed not only through offer and acceptance but also through“other means...Article 471 of the Civil Code of the People’s Republic of China(hereinafter referred to as“the Civil Code”)stipulates that contracts may be formed not only through offer and acceptance but also through“other means.”However,the Civil Code does not provide further clarification on what“other means”entail.This statutory provision represents a departure from the traditional theory of contract formation,which requires a“meeting of the minds.”This study seeks to identify the jurisprudential basis of the Civil Code as a positive law and finds that the theory of de facto contracts,proposed by German scholar Günter Haupt in his lecture titled“On Factual Contractual Relationships”provides a theoretical foundation for the Civil Code’s inclusion of alternative methods of contract conclusion.The theory of de facto contracts argues that for certain types of conduct,the formalities of offer and acceptance are not essential.Instead,contracts can be established through factual processes.This view introduces flexibility to the otherwise rigid doctrine of contractual freedom,allowing for more streamlined and logical judicial analysis.It also balances economic efficiency with principles of fairness and justice,serving the normative values underlying contract law.In this paper,the author proposes that the term“de facto contract”be precisely defined within the context of legislative and judicial practice.This article also recommends limiting the original concept described by Haupt to contracts formed based on legally prescribed factual processes or behaviors.Such contracts can be tentatively termed as“statutory de facto contracts,”which could be examined as a distinct category of contracts in legal theory.展开更多
Wine plays a big role in people's social life both in China and in the West. Based on the perspective of cross culture, thepaper gives a detailed analysis of the disparities of Chinese and western wine culture, an...Wine plays a big role in people's social life both in China and in the West. Based on the perspective of cross culture, thepaper gives a detailed analysis of the disparities of Chinese and western wine culture, and points out the factors for the formingof Chinese and western wine culture. It can be concluded that culture is the key to the understanding of wine phenomenon.展开更多
This paper uses monthly data to examine the autonomy and effectiveness of monetary policy in China under the de facto fixed exchange rate arrangement in place from 1998 to 2005. The results obtained from Granger causa...This paper uses monthly data to examine the autonomy and effectiveness of monetary policy in China under the de facto fixed exchange rate arrangement in place from 1998 to 2005. The results obtained from Granger causality tests in a vector autoregression framework indicate that： （i） China actually conducted independent monetary policy during the fixed exchange rate period; and （ii） market-oriented policy measures are impotent in influencing real output and prices. The framework of the investigation into the autonomy of monetary policy adapts to the Chinese economic condition that primary loan and deposit rates are set by the central bank. Based on the empirical results, the present paper provides alternative strategies to improve the effectiveness of monetary policy in China, including developing the financial system and solidifying microeconomic fundamentals instead of forcing the adaptation of a more flexible exchange rate regime.展开更多
The theory of evolution was advanced by Darwin in 1859, prior to Mendel’s experiments demonstrating the particulate nature of inheritance. The modern synthesis was formulated in the early 1940s, well before the conce...The theory of evolution was advanced by Darwin in 1859, prior to Mendel’s experiments demonstrating the particulate nature of inheritance. The modern synthesis was formulated in the early 1940s, well before the concept of coded information was understood. This paper outlines four mathematical challenges to the modern synthesis, which are based on current understanding of the proposed mechanisms of evolutionary change within the constraints of experimental molecular biology.展开更多
Based on DEA-Malmquist method,this paper calculated the integrated technology efficiency of grain production and total factor productivity and analyzed factors influencing the grain production technology efficiency us...Based on DEA-Malmquist method,this paper calculated the integrated technology efficiency of grain production and total factor productivity and analyzed factors influencing the grain production technology efficiency using working documents of panel structure. Research results indicate that grain production integrated technology efficiency of China is relatively low,technology utilization level is low,and it remains at the stage of decreasing returns to scale,and the pure technology efficiency still has space to increase. Total factor productivity is declining and the total factor productivity of many provinces is relatively low. Since the total factor productivity of eastern areas is higher than central and western areas,it is required to strengthen technological support for grain production. The implementation of urbanization is helpful for promoting increase of grain production technology efficiency in central and eastern areas,but it will exert negative influence on western areas.展开更多
In December 2016, the Nanjing Intermediate People＇s Court in China issued its ruling in the Kolmar vo Sutex case, where a monetary judgment from Singapore was recognized and enforced against a local textile company. ...In December 2016, the Nanjing Intermediate People＇s Court in China issued its ruling in the Kolmar vo Sutex case, where a monetary judgment from Singapore was recognized and enforced against a local textile company. The case confirms that once a foreign country has taken the initiative, Chinese courts will follow up to enforce judgments from that country reciprocally. This is the doctrine of de facto reciprocity adopted by some Chinese courts. The paper surveys the judicial practice of Chinese courts and finds that this area of law is full of confusion and uncertainties due to the lack of applicable rules. Recent developments suggest that China may move away from this approach and adopt a relaxed version of reciprocity, which is worthy of close attention.展开更多
The effects of 14 factors on food production in Huang-Huai-Hai Plain are analyzed by path analysis in this paper,and then the linear regression models of them are established by SPSS software. The results show that el...The effects of 14 factors on food production in Huang-Huai-Hai Plain are analyzed by path analysis in this paper,and then the linear regression models of them are established by SPSS software. The results show that electricity consumption for agriculture,growing area of crops,the affected area,annual average temperature and arable land area at the end of the year have great effects on food production. Finally some recommendations are put forward to improve the food production in Huang-Huai-Hai Plain such as improving the level of agricultural mechanization,stabilizing food production,preventing natural disasters and increasing the effective irrigation area.展开更多
This paper examines the design and the process used to carry out the China Fertility Survey 2017,a national representative survey that collected data on fertility desire,childbearing behavior,the use of childbearing s...This paper examines the design and the process used to carry out the China Fertility Survey 2017,a national representative survey that collected data on fertility desire,childbearing behavior,the use of childbearing services,and the determinants of childbearing behavior.The sampling method adopted was three-stage stratified probabilities proportional to size(PPS),and survey implementation made use of Computer Assisted Personal Interviewing(CAPI).CAPI played a significant role in survey design,last-stage sampling,interviewer training,face-to-face interviews,and questionnaire review and quality control.The survey results were compared with relevant data in the Integrated Management Information System for Population and Family Planning to check consistency.Ex post facto weighting was applied to correct sample structure bias.The process used to acquire accurate personal information is summarized.Suggestions based on consideration of sampling frame distortion by population mobility and other factors are put forward in the hope of improving similar sampling surveys in the future.展开更多
Thermoelectric(TE)materials based on conjugated polymers have received much attention due to their great advantages of solution processibility,light weight,flexibility,and low thermal conductivity.These advantages mak...Thermoelectric(TE)materials based on conjugated polymers have received much attention due to their great advantages of solution processibility,light weight,flexibility,and low thermal conductivity.These advantages make them potential candidates for large-area,low-cost and low-power TE applications.Both efficient p-type and n-type conjugated polymers with high and comparable thermoelectric performance are required for practical TE applications.However,due to the inefficient n-doping efficiency and unstable electron transport of most n-type conjugated polymers,the TE performance of n-type polymers is much poorer than that of their p-type counterparts,impeding the development of polymer TE materials.Great efforts have been made to address the low ndoping efficiency and TE performance of n-type polymers,including the chemical modification of traditional ntype polymers,the design of new n-type conjugated polymers,and the development of more efficient n-dopants,as well as doping engineering.Nowadays,the TE performance of n-type polymers has been greatly improved,indicating a bright future for polymer TE materials.In this review,we summarize the recent progress made on ntype polymer TE materials,mainly focusing on the structure-performance relationships based on promising n-type polymers for TE applications.This review aims to provide some guidelines for future material design.展开更多
In this paper,we use DEA-Tobit model to conduct empirical study on the governmental supply efficiency of public service in Chongqing's 38 counties and the influencing factors during the period 2008-2011.The result...In this paper,we use DEA-Tobit model to conduct empirical study on the governmental supply efficiency of public service in Chongqing's 38 counties and the influencing factors during the period 2008-2011.The results show that the supply efficiency of basic public service at county level is generally low,and there is significant regional differences and strong volatility;per capita GDP,population density and population size,and level of education of the residents,are significantly correlated with the supply efficiency of basic public service at county level,but traffic density,urbanization level,and the proportion of government spending on public service to total fiscal expenditure,have no significant effects on the efficiency of basic public service at county level.Based on this,we propose some policy recommendations for enhancing the level of local economic development and the level of education,and reasonably guiding the residents'agglomeration.展开更多
Following the raw ore export ban announced by Indonesia in January this year,the rising margin of nickel price has topped 60%.At the London Metal Exchange,nickel price has risen from the bottom of USD 13334 per tonne ...Following the raw ore export ban announced by Indonesia in January this year,the rising margin of nickel price has topped 60%.At the London Metal Exchange,nickel price has risen from the bottom of USD 13334 per tonne on January 9 this year to the peak of USD 21625per tonne on May 13,recording a new highest level of nickel price in two years.展开更多
文摘Ulcerative colitis(UC)is a chronic disease characterized by diffuse inflammation of the mucosa of the colon and rectum.The hallmark clinical symptom of UC is bloody diarrhea.The clinical course is marked by exacerbations and remissions,which may occur spontaneously or in response to treatment changes or intercurrent illnesses.UC is most commonly diagnosed in late adolescence or early adulthood,but it can occur at any age.The incidence of UC has increased worldwide over recent decades,especially in developing nations.In contrast,during this period,therapeutic advances have improved the life expectancy of patients,and there has been a decrease in the mortality rate over time.It is important to emphasize that there is considerable variability in the phenotypic presentation of UC.Within this context,certain clinical and demographic characteristics are useful in identifying patients who tend to have more severe evolution of the disease and a poor prognosis.In this group of patients,better clinical surveillance and more intensive therapy may change the natural course of the disease.The aim of this article was to review the epidemiology and demographic characteristics of UC and the factors that may be associated with its clinical prognosis.
文摘Nuclear factor kappa B(NF-κB) has an established role in the regulation of innate immunity and inflammation.NF-κB is also involved in critical mechanisms connecting inflammation and cancer development.Recent investigations suggest that the NF-κB signaling cascade may be the central mediator of gastrointestinal malignancies including esophageal,gastric and colorectal cancers.This review will explore NF-κB's function in inflammation-associated gastrointestinal malignancies,highlighting its oncogenic contribution to each step of carcinogenesis.NF-κB's role in the inflammation-to-carcinoma sequence in gastrointestinal malignancies warrants stronger emphasis upon targeting this pathway in achieving greater therapeutic efficacy.
文摘A significant portion of the national water supply can be attributed to de facto or unplanned potable reuse, though the extent of its contribution is difficult to estimate. Fortunately, the contribution of Water Resource Recovery Facility (WRRF) effluent to waters that supply drinking water treatment plants has been documented by some communities. In the United States (US), among the top 25 most impacted drinking water treatment plants by upstream WRRF, 16% of the influent flow to the drinking water treatment plant under average streamflow and up to 100% under low-flow conditions is WRRF effluent. Currently, the full extent of de facto reuse in the US may be much higher because of population growth. The scenario is no different for Beaufort-Jasper Water and Sewer Authority (BJWSA) in South Carolina, US, with contributions to the Savannah River originating from numerous WRRF and other upstream dischargers. South Carolina coastal utilities such as BJSWA are considering direct and indirect potable reuse options, driven by disposal limitations and challenges. Currently, South Carolina does not have a framework, guidelines, or regulations for reuse, but discussions have started among the regulated community. In addition to understanding the extent of de facto reuse, the state will need to develop standards and best practices to enable future adoption of planned potable reuse solutions to water resources challenges. Such guidance should address human health risk management and technical considerations regarding treatment in addition to other factors, including source control, storage, fail-safe operation, monitoring, non-cost factors, and public acceptance. This study conducted a mapping assessment specific to BJWSA, sampled at four locations on Savannah River, and observed that de facto reuse is approximately 4.6% to 5.9% during low-flow months and is within the range generally observed nationwide. When coupled with evidence that planned potable reuse can improve human health and environmental risks, this practice is
基金The Natural Science Foundation of Zhejiang Province uner contract No.Y5110166
文摘Heavy metals in the surface sediments and sediment core from the Xiangshan Bay, a mariculture base on the coast of the East China Sea, were determined by inductively coupled plasma mass spectrometry（ICP–MS） in order to evaluate their levels and sources. The results showed that the levels of Cu, Pb, Zn, and Cr in the sediments of the bay have been generally influenced by anthropogenic inputs since the founding of the People’s Republic of China. In particular, Cu and Zn were polluted to some extent, as evidenced by high enrichment factors. Organic matter, grain size, wastewater discharge, and low energy hydrodynamic environment played dominant roles in the heavy metal enrichment in the sediments. The ratio of terrigenous source to marine biogenic deposit of trace metals in the sediments was calculated, revealing that terrigenous inputs were the main source of Cu, Pb, and Zn, while biological pellets contributed much more to the enrichment of Cr and Cd. Considering the influence of biological sources on the enrichment of Cd and Cr, and the fact that the sediment has been polluted by Cu and Zn, the development of mariculture and discharge of wastewater into the Bay should be restricted
基金Supported by Grant-in-Aid for Scientific Research(C),The Ministry of Education,Culuture,Sports,Science and Technology and The Institute for Environment and Gender-specific Medicine,Juntendo University Graduate School of Medicine
文摘The pathogenesis of rheumatoid arthritis(RA) remains to be completely elucidated so far; however, it is known that proinflammatory cytokines play a pivotal role in the induction of RA. Tumor necrosis factor(TNF-α), in particular, is considered to play a central role in bone destruction by mediating the abnormal activation of osteoclasts or the production of proteolytic enzymes through direct or indirect mechanisms. The use of TNF-α blocking agents has a significant impact on RA therapy. Anti-TNF-α blocking agents such as infliximab are very effective for treatment of RA, especially for the prevention of articular destruction. We have previously shown that several proteins exhibited extensive changes in their expression after amelioration of RA with infliximab treatment. Among the proteins, connective tissue growth factor(CTGF) has a significantrole for the development of RA. Herein, we review the function of CTGF in the pathogenesis of RA and discuss the possibility of a novel treatment for RA. We propose that CTGF is a potentially novel effector molecule in the pathogenesis of RA. Blocking the CTGF pathways by biological agents may have great beneficial effect in patients with RA.
文摘Article 471 of the Civil Code of the People’s Republic of China(hereinafter referred to as“the Civil Code”)stipulates that contracts may be formed not only through offer and acceptance but also through“other means.”However,the Civil Code does not provide further clarification on what“other means”entail.This statutory provision represents a departure from the traditional theory of contract formation,which requires a“meeting of the minds.”This study seeks to identify the jurisprudential basis of the Civil Code as a positive law and finds that the theory of de facto contracts,proposed by German scholar Günter Haupt in his lecture titled“On Factual Contractual Relationships”provides a theoretical foundation for the Civil Code’s inclusion of alternative methods of contract conclusion.The theory of de facto contracts argues that for certain types of conduct,the formalities of offer and acceptance are not essential.Instead,contracts can be established through factual processes.This view introduces flexibility to the otherwise rigid doctrine of contractual freedom,allowing for more streamlined and logical judicial analysis.It also balances economic efficiency with principles of fairness and justice,serving the normative values underlying contract law.In this paper,the author proposes that the term“de facto contract”be precisely defined within the context of legislative and judicial practice.This article also recommends limiting the original concept described by Haupt to contracts formed based on legally prescribed factual processes or behaviors.Such contracts can be tentatively termed as“statutory de facto contracts,”which could be examined as a distinct category of contracts in legal theory.
文摘Wine plays a big role in people's social life both in China and in the West. Based on the perspective of cross culture, thepaper gives a detailed analysis of the disparities of Chinese and western wine culture, and points out the factors for the formingof Chinese and western wine culture. It can be concluded that culture is the key to the understanding of wine phenomenon.
基金supported by Program for New Century Excellent Talents in University(NCET-08-0762)a research grant of the 211 University Advancement Project entitled "The Autonomy of Monetary Policy and the Flexibility of Exchange Rates" sponsored by the Education Ministry of China
文摘This paper uses monthly data to examine the autonomy and effectiveness of monetary policy in China under the de facto fixed exchange rate arrangement in place from 1998 to 2005. The results obtained from Granger causality tests in a vector autoregression framework indicate that： （i） China actually conducted independent monetary policy during the fixed exchange rate period; and （ii） market-oriented policy measures are impotent in influencing real output and prices. The framework of the investigation into the autonomy of monetary policy adapts to the Chinese economic condition that primary loan and deposit rates are set by the central bank. Based on the empirical results, the present paper provides alternative strategies to improve the effectiveness of monetary policy in China, including developing the financial system and solidifying microeconomic fundamentals instead of forcing the adaptation of a more flexible exchange rate regime.
文摘The theory of evolution was advanced by Darwin in 1859, prior to Mendel’s experiments demonstrating the particulate nature of inheritance. The modern synthesis was formulated in the early 1940s, well before the concept of coded information was understood. This paper outlines four mathematical challenges to the modern synthesis, which are based on current understanding of the proposed mechanisms of evolutionary change within the constraints of experimental molecular biology.
基金Supported by Project of National Natural Science Foundation(71373215)Key Project of Fundamental Research Funds for Southwest University(SWU1309003)Fundamental Research Funds for the Central Universities in 2015(SWU1509317)
文摘Based on DEA-Malmquist method,this paper calculated the integrated technology efficiency of grain production and total factor productivity and analyzed factors influencing the grain production technology efficiency using working documents of panel structure. Research results indicate that grain production integrated technology efficiency of China is relatively low,technology utilization level is low,and it remains at the stage of decreasing returns to scale,and the pure technology efficiency still has space to increase. Total factor productivity is declining and the total factor productivity of many provinces is relatively low. Since the total factor productivity of eastern areas is higher than central and western areas,it is required to strengthen technological support for grain production. The implementation of urbanization is helpful for promoting increase of grain production technology efficiency in central and eastern areas,but it will exert negative influence on western areas.
文摘In December 2016, the Nanjing Intermediate People＇s Court in China issued its ruling in the Kolmar vo Sutex case, where a monetary judgment from Singapore was recognized and enforced against a local textile company. The case confirms that once a foreign country has taken the initiative, Chinese courts will follow up to enforce judgments from that country reciprocally. This is the doctrine of de facto reciprocity adopted by some Chinese courts. The paper surveys the judicial practice of Chinese courts and finds that this area of law is full of confusion and uncertainties due to the lack of applicable rules. Recent developments suggest that China may move away from this approach and adopt a relaxed version of reciprocity, which is worthy of close attention.
基金Supported by Soft Science Project of Shandong Province(2009RKB01052)
文摘The effects of 14 factors on food production in Huang-Huai-Hai Plain are analyzed by path analysis in this paper,and then the linear regression models of them are established by SPSS software. The results show that electricity consumption for agriculture,growing area of crops,the affected area,annual average temperature and arable land area at the end of the year have great effects on food production. Finally some recommendations are put forward to improve the food production in Huang-Huai-Hai Plain such as improving the level of agricultural mechanization,stabilizing food production,preventing natural disasters and increasing the effective irrigation area.
文摘This paper examines the design and the process used to carry out the China Fertility Survey 2017,a national representative survey that collected data on fertility desire,childbearing behavior,the use of childbearing services,and the determinants of childbearing behavior.The sampling method adopted was three-stage stratified probabilities proportional to size(PPS),and survey implementation made use of Computer Assisted Personal Interviewing(CAPI).CAPI played a significant role in survey design,last-stage sampling,interviewer training,face-to-face interviews,and questionnaire review and quality control.The survey results were compared with relevant data in the Integrated Management Information System for Population and Family Planning to check consistency.Ex post facto weighting was applied to correct sample structure bias.The process used to acquire accurate personal information is summarized.Suggestions based on consideration of sampling frame distortion by population mobility and other factors are put forward in the hope of improving similar sampling surveys in the future.
基金the financial support of the National Natural Science Foundation of China(No.21625403,21875244,21875241,22075271)。
文摘Thermoelectric(TE)materials based on conjugated polymers have received much attention due to their great advantages of solution processibility,light weight,flexibility,and low thermal conductivity.These advantages make them potential candidates for large-area,low-cost and low-power TE applications.Both efficient p-type and n-type conjugated polymers with high and comparable thermoelectric performance are required for practical TE applications.However,due to the inefficient n-doping efficiency and unstable electron transport of most n-type conjugated polymers,the TE performance of n-type polymers is much poorer than that of their p-type counterparts,impeding the development of polymer TE materials.Great efforts have been made to address the low ndoping efficiency and TE performance of n-type polymers,including the chemical modification of traditional ntype polymers,the design of new n-type conjugated polymers,and the development of more efficient n-dopants,as well as doping engineering.Nowadays,the TE performance of n-type polymers has been greatly improved,indicating a bright future for polymer TE materials.In this review,we summarize the recent progress made on ntype polymer TE materials,mainly focusing on the structure-performance relationships based on promising n-type polymers for TE applications.This review aims to provide some guidelines for future material design.
基金Supported by National Social Science Fund Project(11BGL055)Humanities and Social Science Planning Project,Ministry of Education(10 YJAZH016)Chongqing Municipal Social Science Planning Project(2009 JJ 06)
文摘In this paper,we use DEA-Tobit model to conduct empirical study on the governmental supply efficiency of public service in Chongqing's 38 counties and the influencing factors during the period 2008-2011.The results show that the supply efficiency of basic public service at county level is generally low,and there is significant regional differences and strong volatility;per capita GDP,population density and population size,and level of education of the residents,are significantly correlated with the supply efficiency of basic public service at county level,but traffic density,urbanization level,and the proportion of government spending on public service to total fiscal expenditure,have no significant effects on the efficiency of basic public service at county level.Based on this,we propose some policy recommendations for enhancing the level of local economic development and the level of education,and reasonably guiding the residents'agglomeration.
文摘Following the raw ore export ban announced by Indonesia in January this year,the rising margin of nickel price has topped 60%.At the London Metal Exchange,nickel price has risen from the bottom of USD 13334 per tonne on January 9 this year to the peak of USD 21625per tonne on May 13,recording a new highest level of nickel price in two years.
