774 research outputs found
Trends in tariff reforms and trends in wage inequality
The authors provide new evidence on the impacts of trade reforms on wages and wage inequality in developing countries. While most of the current literature on the topic achieves identification by comparing outcomes before and after one episode of trade liberalization across industries, they propose a stronger identifying strategy. The authors explore the recent historical record of policy changes adopted by Argentina: from significant protection in the early 1970s, to the first episode of liberalization during the late 1970s, back to a slowdown of reforms during the 1980s, to the second episode of liberalization in the 1990s. These swings in trade policy comprise broken trends in trade reforms that they can compare with observed trends in wages and wage inequality. After setting up unusual historical data sets of trends in tariffs, trends in wages, and trends in wage inequality, the evidence supports two well-known hypotheses: trade liberalization, other things being equal, (1) has reduced wages, and (2) has increased wage inequality.Free Trade,Economic Theory&Research,Trade Policy,Export Competitiveness,Labor Markets
Spatial localization for a general reaction-diffusion system
We use a local energy method to study the spatial localization of the supports of the solutions of a reaction-diffusion system with nonlinear diffusion and a general reaction term. We establish finite speed of propagation and the existence of waiting times under a set of weak assumptions on the structural form of the system. These assumptions allow for additive and multiplicative reaction terms and space-and time-dependence of the coefficients, as well as a divergence-free convection term
Existence and uniqueness of solutions to the Boussinesq system with nonlinear thermal diffusion
The Boussinesq system arises in Fluid Mechanics when motion is governed by density gradients caused by temperature or concentration differences. In the former case, and when thermodynamical coefficients are regarded as temperature dependent, the system consists of the Navier-Stokes equations and the non linear heat equation coupled through the viscosity, bouyancy and convective terms. According to the balance between specific heat and thermal conductivity the diffusion term in the heat equation may lead to a singular or degenerate parabolic equation. In this paper we prove the existence of solutions of the general problem as well as the uniqueness of solutions when the spatial dimension is two
La aplicación de las IDEs en la enseñanza en ingenierÃa
Las Infraestructuras de Datos Espaciales (IDEs) cada vez más cobran relevancia como recurso docente en la enseñanza en carreras técnicas. Las IDEs permiten a los estudiantes acceder vÃa Web a información geográfica que les es de utilidad en el desarrollo de supuestos prácticos, asà como refuerza sus habilidades. Tras la publicación de la Directiva Europea INSPIRE es obligatoria su instalación. Ello ha supuesto un desafÃo en la formación de personal especializado en temática. Dada las caracterÃsticas de la información a la que se refiere, el desarrollo de recursos didácticos para introducir esta formación en carreras técnicas se considera crucial. En el presente trabajo, se desarrolla una experiencia piloto que expone las fortalezas y debilidades de su utilización como recurso docente
Influence of meteorological input data on backtrajectory cluster analysis ? a seven-year study for southeastern Spain
International audienceBacktrajectory differences and clustering sensitivity to the meteorological input data are studied. Trajectories arriving in Southeast Spain (Elche), at 3000, 1500 and 500 m for the 7-year period 2000?2006 have been computed employing two widely used meteorological data sets: the NCEP/NCAR Reanalysis and the FNL data sets. Differences between trajectories grow linearly at least up to 48 h, showing faster growing after 72 h. A k-means cluster analysis performed on each set of trajectories shows differences in the identified clusters (main flows), partially because the number of clusters of each clustering solution differs for the trajectories arriving at 3000 and 1500 m. Trajectory membership to the identified flows is in general more sensitive to the input meteorological data than to the initial selection of cluster centroids
Air mass origin and its influence over the aerosol size distribution: a study in SE Spain
International audienceA k-means cluster analysis of 96 hour trajectories arriving in Southeast (SE) Spain at 3000, 1500 and 500 m for the 7-year period 2000?2006 has been performed to identify and describe the main flows arriving at the study area. The dependence of the aerosol size distribution on the air mass origin has been studied by using non-parametric statistics. There are statistically significant differences on aerosol size distribution and meteorological variables at surface level according to the identified clusters
On a quasilinear degenerated system arising in semiconductors theory
A drift-diffusion model for semiconductors with nonlinear diffusion is considered. The model consists of two quasilinear degenerated parabolic equations for the carrier densities and the Poisson equation for the electric potential. We also assume Lipschitz continuous non linearities in the drift and {em generation-recombination terms. Existence of weak solutions is proven by using a regularization technique. Uniqueness of solutions is proven when either the diffusion term is strictly increasing and solutions have spatial derivatives in or when is non decreasing and a suitable entropy condition is fullfilled by the electric potential
Dise?o, procura y construcci?n del CENCUL RURICANCHO ? SJL en el distrito de San Juan de Lurigancho, provincia de Lima - Per?
El proyecto Dise?o, procura y construcci?n del CENCUL RURICANCHO ? SJL en el distrito de San Juan de Lurigancho, provincia de Lima ? Per?, es un proyecto de inversi?n p?blica patrocinado por la municipalidad distrital de San Juan de Lurigancho, cuyo desarrollo y ejecuci?n se realizar? bajo el sistema de inversi?n p?blica INVIERTE.PE y la Ley de Contrataciones con el Estado por la empresa GALGON S.A.C. adjudicado mediante concurso p?blico de m?ritos. El centro cultural CENCUL RURICANCHO ?SJL es una infraestructura de car?cter social y cultural mediante el cual se cubrir? la deficiencia existente de espacios de socializaci?n y reuni?n comunitarios bajo condiciones ?ptimas de seguridad, confort, funcionalidad, calidad arquitect?nica y constructiva. El alcance de la tesis abarca el inicio y planificaci?n bajo el enfoque de los lineamientos de direcci?n de proyectos del PMBOK? 5ta edici?n, de las fases de dise?o y desarrollo del expediente t?cnico, la procura, construcci?n y puesta en marcha del CENCUL RURICANCHO ? SJL, cuya ejecuci?n generar? un gran impacto permitiendo el reordenamiento urbano y revalorizaci?n de la zona, el impulso para la creaci?n de nuevas oportunidades de negocio y ser el nuevo referente de la identidad e imagen del distrito y sus pobladores
An approach to research-based design of teaching-learning sequences in the context of physics education: Theoretical frameworks, pedagogical methods, and examples of Data Analysis
In this paper we discuss an example of the research approaches practiced at the University of Palermo Physics Education Research Group (UoPPERG). Particularly, we discuss the design and development with groups of high school students of two Teaching-Learning Sequences (TLSs) on surface phenomena in liquids, and the data collection and analysis methods. In the introduction, we briefly discuss the educational reconstruction model, that we use as a theoretical framework for the designing of the TLSs, and a pedagogical methodology that in the last years has gained consensus among educators, i.e., active learning. Some considerations on active learning pedagogical and cognitive psychology foundations are also made. The main aim of the TLSs is to improve students' learning of surface phenomena, a topic that is quite relevant in Physics and other scientific and technical fields. We provide a research-based, conceptual scheme of what we mean by "improvement of students' learning", and present the TLSs phases, that are based on the well-known inquiry-and investigation-based learning approaches, that are science-specific applications of the general idea of active learning. Then, we describe some methods we use in our researches to collect and give an example of the data analysis needed to study the progression of student learning, with respect to the conceptual scheme provided, and of some of the results obtained
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