Survey of Hemileia vastatrix races from Peru to identify potential coffee mutants with disease resistance

info:eu-repo/semantics/publishedVersio

Migration Costs and Networks: household optimal investment in migration

International migration is an expensive form of investment, that only households relatively better off can afford. However poorer households have the higher incentive to migrate. Migration decision is conditional on the entry cost, expected returns and risks of migration. This paper, using data from Mexican rural and urban areas, examines the relation between household and community networks and costs and risks of migration focusing on the optimal investment in migration. To investigate an household optimal number of migrants this paper introduces a Three Step procedure to solve simultaneously for the endogeneity of network size and possible selection of migrants. The analysis confirms the inverted U-shaped relation between wealth and migration, stressing the importance of networks particularly in facilitating the migration of social strata belonging to the left tail of the income distribution. Moreover, in presence of sunk costs and/or high initial investment, household and community networks accomplish different functions

Determinants and consequences of international migration

This chapter provides a simple overview of the canonical model of international migration, discusses the consequences of migration on both sending and receiving countries and draws some considerations on future research prospects for the international migration literature

Job Polarization and Structural Change

We document that job polarization -contrary to the consensus- has started as early as the 1950s in the US: middle-wage workers have been losing both in terms of employment and average wage growth compared to low- and high-wage workers. Given that polarization is a long-run phenomenon and closely linked to the shift from manufacturing to services, we propose a structural change driven explanation, where we explicitly model the sectoral choice of workers. Our simple model does remarkably well not only in matching the evolution of sectoral employment, but also of relative wages over the past fifty years

Simulacao numérica do campo de velocidade em fístula arteriovenosa

The objective of this study is to analyze the hemodynamic factors of flow in an arteriovenous fistula (AVF). The geometric model of the AVF is obtained virtually from a computed tomography. In the mathematical model, which simulates blood flow in the AVF, it is considered a non-Newtonian fluid, incompressible and transient laminar flow. The flow behavior in the AVF is given by the blood velocity in five points corresponding to the mass flow in the systolic phase and in the diastolic phase. The numerical simulation of the velocity field in the systolic phasepresented greater intensity of axial and radial recirculations. The presence of recirculations allows figurative elements to collide excessively in the wall of the endotheliumO objetivo deste trabalho e analisar os fatores hemodinamicos do escoamento numa fístula arteriovenosa (FAV). O modelo geométrico da FAV é obtido virtualmente a partir de uma tomografia computadorizada. No modelo matemático, que simula o fluxo da sangue na FAV, é considerado um fluido nao-Newtoniano, escoamento laminar, incompressível e em regime transiente. O comportamento do fluxo na FAV é dado pela velocidade do sangue em cinco pontos correspondente á vazao mássica em fase sistólica e em fase diastólica. A simulacao numérica do campo de velocidade na fase sistólica apresentou maior intensidade de recirculacoes axiais e radiais. A presenca de recirculacoes permite que elementos figurados se choquem excessivamente na parede do endotélio