Like oil and water or chocolate and peanut butter? Ethnic diversity and social participation of young people in England

The paper studies the impact of ethnic diversity on social participation of young people. We first propose a theoretical model in which the agents choose between structured and unstructured social activities by taking into account the ethnic composition of the groups they join. We test our predictions using English census data together with the “Longitudinal Survey of Young People in England” (LSYPE) and we find that ethnic segregation increases the probability of hanging around near home, while ethnic fractionalization decreases it. Furthermore, more structured activities are not affected by ethnic fractionalization. Finally, we use an IV strategy based on both historical and geographical data to correct for endogenous sorting into neighborhoods. The results we get are even stronger than those obtained where the ethnic composition of the neighborhood is taken as exogenous.Social participation, Fractionalization, Segregation

Landscaping Hispaniola Moreau de Saint-Méry's border politics

This article focuses on Médéric Louis Élie Moreau de Saint-Méry's <i>Description Topographique et Politique de la partie espagnole de l'Isle Saint-Domingue </i>(1796) and his <i>Description Topographique, Physique, Civile, Politique et Historique de la partie française de l'Isle Saint-Domingue </i> (1797). The Descriptions were both written before the beginning of the French Revolution and the 1791 slave revolt in Saint Domingue but were published when the colonial frontier had been abolished (at least de jure if not de facto) by the 1795 Peace of Basle. Overall, the article argues that the two Descriptions are ultimately committed to the (re)inscription of the colonial frontier but intriguingly oscillate between its erasure and its reinforcement. It begins by focusing on Saint-Méry's territorial projections and appropriative landscaping of the Spanish colony; it highlights the important role played by the border in the racial politics of Hispaniola and then revisits Saint-Mery's border politics on the island in the light of the author's conviction that France should reannex Louisiana, given to Spain in 1762

Dual virtual element method in presence of an inclusion

We consider a Darcy problem for saturated porous media written in dual formulation in presence of a fully immersed inclusion. The lowest order virtual element method is employ to derive the discrete approximation. In the present work we study the effect of cells with cuts on the numerical solution, able to geometrically handle in a more natural way the inclusion tips. The numerical results show the validity of the proposed approach

Tax Systems and tax reforms in Latin America, Part I : country studies, Colombia

This paper is a part of a wider research concerning taxation in the main world economic areas, carried on at the Department of Public economic on the University of Pvia, Italy, directed by L. Bernardi and P. Profeta, under the supervision of Vito Tanzi. The paper illustrates and discusses the Colombian tax ssystems with respect to its structure, developments and reforms until the last chenges of 2007, December.Tax Systems Tax Reforms Colombia

Dual virtual element method for discrete fractures networks

Discrete fracture networks is a key ingredient in the simulation of physical processes which involve fluid flow in the underground, when the surrounding rock matrix is considered impervious. In this paper we present two different models to compute the pressure field and Darcy velocity in the system. The first allows a normal flow out of a fracture at the intersections, while the second grants also a tangential flow along the intersections. For the numerical discretization, we use the mixed virtual finite element method as it is known to handle grid elements of, almost, any arbitrary shape. The flexibility of the discretization allows us to loosen the requirements on grid construction, and thus significantly simplify the flow discretization compared to traditional discrete fracture network models. A coarsening algorithm, from the algebraic multigrid literature, is also considered to further speed up the computation. The performance of the method is validated by numerical experiments

Non-local formulation of ghost-free bigravity theory

We study the ghost-free bimetric theory of Hassan and Rosen, with parameters $\beta_i$ such that a flat Minkowski solution exists for both metrics. We show that, expanding around this solution and eliminating one of the two metrics with its own equation of motion, the remaining metric is governed by the Einstein-Hilbert action plus a non-local term proportional to $W_{\mu\nu\rho\sigma} (\Box-m^2)^{-1}W^{\mu\nu\rho\sigma}$, where $W_{\mu\nu\rho\sigma}$ is the Weyl tensor. The result is valid to quadratic order in the metric perturbation and to all orders in the derivative expansion. This example shows, in a simple setting, how such non-local extensions of GR can emerge from an underlying consistent theory, at the purely classical level.Comment: 16 page