WORKERS,WARRIORS, AND CRIMINALS: SOCIAL CONFLICT IN GENERAL EQUILIBRIUM

We incorporate appropriation activities (social conflict) into canonical models of trade and study how economic shocks and policies affect the intensity of conflict. We show that not all shocks that could make society richer reduce conflict: positive shocks to labor‐intensive industries diminish conflict, while positive shocks to capital‐intensive industries increase it. The key requirement is that conflict activities be more labor intensive than the economy as this determines how shocks affect the returns and costs of conflict. Our theory is consistent with several observed patterns of conflict and implies that empirical work should take into account the relative factor intensities of the productive and conflict sectors in each country. Incorporating appropriation into a canonic general equilibrium model affects what policies may be deemed desirable: in order to reduce conflict and generate Pareto‐improvements policy must be distortionary, while reforms that appear efficiency‐enhancing under the unrealistic assumption of perfect property rights may backfire. This offers one explanation for why reforms based on traditional models without appropriation may be delayed and become unpopular when implemented, and why societies may sympathize with seemingly inefficient redistribution.     

培养全球化的领导和管理人才

现在,很多人已经认识到,管理者和领导者并非等同关系。早在1992年,埃德加·沙因（Edgar Schein）就曾说过,领导者“创建、变革文化,管理者弘扬文化”。但是,公司从创建、成长到最终发展为成功的全球化企业,既离不开管理能力,也离不开领导能力。因此,管理和领导是两种不同的才能,尽管我们可能或多或少地具备某些先天的智力潜能,但这两种才能必须经过后天的培养与发展。换言之,领导、管理和创业能力并非什么天赋异禀,而是后天学习的结果。     

Functional connectivity in urban landscapes promoted by <Emphasis Type="Italic">Ramphastos toco</Emphasis> (Toco Toucan) and its implications for policy making

The scarcity of green areas in urban landscapes hinders connectivity among sites reducing the flux of organisms and seed dispersal. Ramphastos toco is an effective plant disperser in tropical landscapes, playing an important role in conserving plant connectivity. In this study we combined two methods of landscape connectivity analysis, in a way not yet explored, to assess the potential contribution of Ramphastos toco to enhancing connectivity among urban vegetation patches. We used spatial modeling techniques to evaluate least cost routes, or those that facilitate bird movement through green urban areas, in Belo Horizonte, a city in Southeast Brazil. We also assessed the relative importance of forest patches for conserving both bird and seed dispersal fluxes using the integral index of connectivity. The resulting least cost route of greater accessibility for the species included in its course an important forest patch under environmental licensing for the construction of a residential condominium. The number of green urban areas covered by forest, of highest habitat quality for the species, summed to 155 patches. Of this total only 5.2% were relevant for regional connectivity, while the four most important patches are targeted by the city’s expansion plans. Ramphastos toco is an effective connector for tropical green urban areas given its adaptability, wide range of movement and seed dispersal effectiveness. We emphasize the need for incorporating ecological knowledge and the prioritization of green areas into city planning, since current expansion projects jeopardize forest patches that are crucial to the functional connectivity of the urban landscape.     

THE LONG‐TERM EFFECTS OF CONDITIONAL CASH TRANSFERS ON CHILD LABOR AND SCHOOL ENROLLMENT

This paper investigates the long‐term effects of conditional cash transfers on school attainment and child labor. To this end, we construct a dynamic heterogeneous agent model, calibrate it with Brazilian data, and introduce a policy similar to the Brazilian Bolsa Família. Our results suggest that this type of policy has a very strong impact on educational outcomes, sharply increasing primary school completion. The conditional transfer is also able to reduce the share of working children from 22% to 17%. We then compute the transition to the new steady state and show that the program actually increases child labor over the short run, because the transfer is not enough to completely cover the schooling costs, so children have to work to be able to comply with the program's schooling eligibility requirement. We also evaluate the impacts on poverty, inequality, and welfare. (JEL O11, I25, J24)     

Towards sociology from the arts: An epistemological turn

Over the past two decades, Howard Becker's Art Worlds and Pierre Bourdieu's The Rules of Art were guidelines for the dominant paradigms in sociology of art. Nevertheless, according to Bourdieu, sociology and art do not make a good match. To overcome this dilemma, the French sociologist Nathalie Heinich proposed a “sociology from art,” based on the uniqueness of artists and their works, but she neglected artworks as sociological subject. A realistic and persistent criticism against sociology from the arts claims that artworks are fictions created by artists, therefore epistemologically unacceptable as social realities. Is it possible the making of sociology from artworks? Through theoretical review and using the example of literature, I will argue in this paper that artworks are important heuristic resources and a legitimate subject of sociological research.     

An optimization approach applied to the optimal stratification problem

A new optimization algorithm is presented to solve the stratification problem. Assuming the number L of strata and the total sample size n are fixed, we obtain strata boundaries by using an objective function associated with the variance. In this problem, strata boundaries must be determined so that the elements in each stratum are more homogeneous among themselves. To produce more homogeneous strata, this paper proposes a new algorithm that uses the Greedy Randomized Adaptive Search Procedure (GRASP) methodology. Computational results are presented for a set of problems, with the application of the new algorithm and some algorithms from literature.     

Urban gradients alter the diversity,specific composition and guild distribution in tropical butterfly communities

The increasing expansion of the urban environment has been considered one of the causes of biodiversity loss. Due to the decrease of the quantity and quality of habitats, this process causes the restriction of organisms to sometimes-specific microhabitats. The patterns of variation of the biodiversity along the environmental gradients, however, are still poorly understood. This study evaluated how urban gradients affect the diversity, specific composition and frequency of guild of the community of butterflies. Butterflies were collected in three transects continuously traversing the urban, rural and preserved habitats using baited traps and by active sampling. We found that the urban gradient acts as an environmental filter in the butterfly communities, reducing the richness and frequency of guilds of frugivorous butterflies, structuring the community through turnover, but without effects in the abundance. This study shows the importance of the urban gradients approach in the butterfly community and its applicability in the management of urban areas in order to include native vegetation along the gradients, aiming at increasing environmental heterogeneity, to preserve butterflies and maintain the ecosystem services and network interactions in altered landscapes.

     

The Child Support Enforcement Amendments of 1984 and Educational Attainment of Young Adults in the United States

ABSTRACT: We compare changes in the effect of child support payments on the educational attainment of children age 16 to 19 before and after passage of the Child Support Enforcement Amendments of 1984, which strengthened enforcement of child support obligations in the United States. Using 1979, 1984, and 1988 Current Population Survey data, we hypothesize and find a decline in the positive effect of child support between 1984 and 1988 that exceeds any earlier decline. Instrumental variables estimates provide additional evidence consistent with the idea that child support serves as an indicator of unobservable characteristics of noncustodial fathers who pay support.