合作社对小农户发展生态农业的影响——基于倾向得分匹配法的实证分析

以湖南省298户小农户作为研究对象,运用倾向得分匹配法来评估其在发展生态农业过程中合作社的中介作用.结果 显示:不同匹配方法的平均处理效应为加入合作社比不加入的小农户高23.7％的可能性.合作社在不同协变量的中介效应由强到弱依次为:认知能力、学历程度、市场预期、政策感知、农业年收入,这说明合作社是稳定且有效的中介.因此建议:为了使乡村振兴战略中扶持小农户发展生态农业的指导意见尽快实施,应优先选择自我发展能力强、整体素质较高的合作社作为扶持对象.以合作社为中介的小农户生态转型,为了实现可持续性和不可逆转性,要以一定的市场需求为驱动.本文所得结论可为立志转型的小农户规避风险提供有价值的建议,并为农业部门制定相关的扶持政策提供一定的依据与参考.     

Living on the Edge: Neighborhood Boundaries and the Spatial Dynamics of Violent Crime

Neighborhood boundaries are a defining aspect of highly segregated urban areas. Yet, few studies examine the particular challenges and spatial processes that occur at the bordering region between two neighborhoods. Extending the growing literature on spatial interdependence, this article argues that neighborhood boundaries—defined as sharp changes in the racial or socioeconomic composition of neighborhoods—are a salient feature of the spatial structure with implications for violent crime and other outcomes. Boundaries lack the social control and cohesion of adjacent homogeneous areas, are contested between groups provoking intergroup conflict, and create opportunities for criminal behavior. This article presents evidence linking racial neighborhood boundaries to increased violent crime. The findings illustrate the importance of neighborhood boundaries for our understanding of spatial dimensions of population dynamics above and beyond the characteristics of neighborhoods.     

Long-Term Earnings Differentials Between African American and White Men by Educational Level

This paper investigates long-term earnings differentials between African American and white men using data that match respondents in the Survey of Income and Program Participation to 30 years of their longitudinal earnings as recorded by the Social Security Administration. Given changing labor market conditions over three decades, we focus on how racial differentials vary by educational level because the latter has important and persistent effects on labor market outcomes over the course of an entire work career. The results show that the long-term earnings of African American men are more disadvantaged at lower levels of educational attainment. Controlling for demographic characteristics, work disability, and various indicators of educational achievement does not explain the lower long-term earnings of less-educated black men in comparison to less-educated white men. The interaction arises because black men without a high school degree have a larger number of years of zero earnings during their work careers. Other results show that this racial interaction by educational level is not apparent in cross-sectional data which do not provide information on the accumulation of zero earnings over the course of 30 years. We interpret these findings as indicating that compared to either less-educated white men or highly educated black men, the long-term earnings of less-educated African American men are likely to be more negatively affected by the consequences of residential and economic segregation, unemployment, being out of the labor force, activities in the informal economy, incarceration, and poorer health.     

The Use of the Partnering Concept for Public–Private Collaboration: How Well Does it Really Work?

This paper critically scrutinizes the key success factors and tools described in the partnering literature by exploring how they are implemented in a public–private partnering collaboration. In addition to this the paper investigates to what extent these tools facilitate the relationship between the parties in a partnering process. The empirical data consist of two longitudinal case studies. Both cases are large and complex urban development projects in the Swedish water and sewage industry. The results from the cases were ambiguous and positive; as well, some negative outcomes were present. Further, the processes were in both cases far from easy and it required a lot of effort from the parties in the collaboration to make the collaboration work and establish a culture based on trust, especially higher up in the organization. As could be expected, the reality is thus far more complex and cumbersome than previous studies indicate.     

The Evolving and Complementary Impacts of Transportation Infrastructures on Population and Employment Change in the United States, 1970–2010

Transportation infrastructures play an essential role in influencing population and employment change. While railroads, highways, and airports were constructed in different time periods, now they complement each other in terms of providing accessibility. This study uses county-level data to examine the impacts of the three forms of transportation infrastructure on population and employment change in the continental United States from 1970 to 2010. The findings suggest that transportation infrastructures play evolving but complementary roles in affecting population and employment change during the study period: railroads act as a distributive factor, highways take a facilitator role, and airports behave like growth poles. Diversification of the roles indicates that transportation infrastructures have evolved from a pure growth factor to an essential multifaceted development element of human society.     

Unterstützung dualer Karrieren im Spitzensport

The longstanding focus of elite athletes on top sports entails disadvantages hampering their later entry to the world of work. In order to successfully contribute their outstanding personality traits to a later job, athletes are thus particularly required to care for their employability. Contributing to this, the author carried out a competency balancing with top athletes. This coaching method significantly decreased the athletes’ need for self-information. Evaluation further showed indications of increased clarity and certainty of occupational goals as well as work satisfaction.     

The matching extension problem in general graphs is co-NP-complete

A simple connected graph G with 2n vertices is said to be k-extendable for an integer k with \(0<k<n\) if G contains a perfect matching and every matching of cardinality k in G is a subset of some perfect matching. Lakhal and Litzler (Inf Process Lett 65(1):11–16, 1998) discovered a polynomial algorithm that decides whether a bipartite graph is k-extendable. For general graphs, however, it has been an open problem whether there exists a polynomial algorithm. The new result presented in this paper is that the extendability problem is co-NP-complete.     

What is Happening with Quality of Life Among the Oldest People in Southern European Countries? An Empirical Approach Based on the SHARE Data

Population aging in developed countries has created new challenges to improve the well-being of individuals at different age cohorts. This issue is especially significant for Southern European countries, were aging societies have worse health and less socio-economic resources. The aim of this study is to contribute to this body of literature and to estimate the effect of aging on quality of life of oldest people. This paper uses the latest available data (6th wave) from the Survey on Health, Ageing and Retirement in Europe (SHARE). Specifically, robust ordinary least squares and multilevel regressions are employed to analyse the effects of socioeconomic, health, and community factors on quality of life among the oldest population for Southern European countries. Our findings confirm the significance of several factors on life satisfaction among the oldest population in this group of countries. Moreover, we show that the determinants which are correlated with quality of life include predisposing, health, geographic area and social isolation factors.     

Klassen messen

The article investigates whether Austrian sociological research empirically addressed social class conceptions between 1945 and 1990. Contrary to the German reception, we find that, indeed, during the whole period scientific publications analyzed social relations and social change from a class perspective with an empirical approach. We embed this research in its historical context in order to work out the implicit explanations given concerning the existence of social inequalities. Moreover, we work out if post-World War II Austrian class analysis did link its work to the Austro-Marxist tradition that flourished between the two World Wars. The empirical focus of the article lies on scientific publications with an empirical approach to social classes and social change.