6,129 research outputs found
ÂżExplica el teorema Stopler-Samuelson el desplazamiento de los salarios? El vĂnculo entre el comercio internacional y los salarios en paĂses latinoamericanos
(Disponible en idioma inglĂ©s Ăşnicamente) ÂżDe quĂ© manera incide la apertura en la brecha de salarios entre los trabajadores calificados y los no calificados? El modelo de comercio de Heckscher-Ohlin (HO) ofrece una predicciĂłn de la relaciĂłn entre salarios y precios. Sin embargo, sus versiones Stolper-Samuelsony de factores especĂficos (SF) simples hacen predicciones opuestas sobre la correlaciĂłn entre los precios y los salarios de ciertos tipos de trabajadores (factores especĂficos en ciertos ramos de actividad) cuando no se usan intensivamente. El análisis de este trabajo ofrece elementos de juicio que pueden permitir distinguir empĂricamente entre estas dos versiones del modelo HO, empleando datos de salarios provenientes de encuestas de hogares en varios paĂses latinoamericanos: Bolivia, MĂ©xico y Venezuela. Se analizan dos especificaciones distintas de factores especĂficos: trabajadores preparados y trabajadores experimentados. En sĂntesis, los resultados favorecen a SS, cuando se define a los trabajadores preparados como el factor especĂfico de estos paĂses latinoamericanos de finales de los años 80 hasta mediados de los 90.
Constraint propagation in N+1-dimensional space-time
Higher dimensional space-time models provide us an alternative interpretation
of nature, and give us different dynamical aspects than the traditional
four-dimensional space-time models. Motivated by such recent interests,
especially for future numerical research of higher-dimensional space-time, we
study the dimensional dependence of constraint propagation behavior. The
Arnowitt-Deser-Misner evolution equation has matter terms which depend on ,
but the constraints and constraint propagation equations remain the same. This
indicates that there would be problems with accuracy and stability when we
directly apply the ADM formulation to numerical simulations as we have
experienced in four-dimensional cases. However, we also conclude that previous
efforts in re-formulating the Einstein equations can be applied if they are
based on constraint propagation analysis.Comment: 4 pages, to appear in Gen. Rel. Gra
Diagonalizability of Constraint Propagation Matrices
In order to obtain stable and accurate general relativistic simulations,
re-formulations of the Einstein equations are necessary. In a series of our
works, we have proposed using eigenvalue analysis of constraint propagation
equations for evaluating violation behavior of constraints. In this article, we
classify asymptotical behaviors of constraint-violation into three types
(asymptotically constrained, asymptotically bounded, and diverge), and give
their necessary and sufficient conditions. We find that degeneracy of
eigenvalues sometimes leads constraint evolution to diverge (even if its
real-part is not positive), and conclude that it is quite useful to check the
diagonalizability of constraint propagation matrices. The discussion is general
and can be applied to any numerical treatments of constrained dynamics.Comment: 4 pages, RevTeX, one figure, added one paragraph in concluding
remarks. The version to appear in Class. Quant. Grav. (Lett
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