Changes in Human Capital and Wage Inequality in Mexico

Over the last two decades Mexico has witnessed a significant increase in wage inequality, typically attributed to the increase in relative demand for skilled labor. Over this period the educational achievements and their distribution across the labor force have also changed substantially. In this paper we analyze the impact of changes in human capital on wage inequality in Mexico. We focus our analysis on decomposing (1) the level of inequality in any given year and (2) change in inequality over time, into observable (e.g. age, education, occupation, etc.) and unobservable differences across workers. The main findings of this paper are: unobservable factors (within group inequality) account for most of the inequality in any given year. Among the observable factors human capital emerges as the most important variables in explaining the level of, and changes in, inequality

Changes in Human Capital and Wage Inequality in Mexico

Over the last two decades Mexico has witnessed a significant increase in wage inequality, typically attributed to the increase in relative demand for skilled labor. Over this period the educational achievements and their distribution across the labor force have also changed substantially. In this paper we analyze the impact of changes in human capital on wage inequality in Mexico. We focus our analysis on decomposing (1) the level of inequality in any given year and (2) change in inequality over time, into observable (e.g. age, education, occupation, etc.) and unobservable differences across workers. The main findings of this paper are: unobservable factors (within group inequality) account for most of the inequality in any given year. Among the observable factors human capital emerges as the most important variables in explaining the level of, and changes in, inequality

Geology of the Barrilla Mountains, Texas

UT Librarie

Slow dynamics in the 3--D gonihedric model

We study dynamical aspects of three--dimensional gonihedric spins by using Monte--Carlo methods. The interest of this family of models (parametrized by one self-avoidance parameter $\kappa$) lies in their capability to show remarkably slow dynamics and seemingly glassy behaviour below a certain temperature $T_g$ without the need of introducing disorder of any kind. We consider first a hamiltonian that takes into account only a four--spin term ($\kappa=0$), where a first order phase transition is well established. By studying the relaxation properties at low temperatures we confirm that the model exhibits two distinct regimes. For $T_g< T < T_c$, with long lived metastability and a supercooled phase, the approach to equilibrium is well described by a stretched exponential. For $T<T_g$ the dynamics appears to be logarithmic. We provide an accurate determination of $T_g$. We also determine the evolution of particularly long lived configurations. Next, we consider the case $\kappa=1$, where the plaquette term is absent and the gonihedric action consists in a ferromagnetic Ising with fine-tuned next-to-nearest neighbour interactions. This model exhibits a second order phase transition. The consideration of the relaxation time for configurations in the cold phase reveals the presence of slow dynamics and glassy behaviour for any $T< T_c$. Type II aging features are exhibited by this model.Comment: 13 pages, 12 figure

Lepton Flavour Violation in Unified Models with U(1)-Family Symmetries

Lepton flavour non-conserving processes are examined in the context of unified models with U(1)-family symmetries which reproduce successfully the low-energy hierarchy of the fermion mass spectrum and the Kobayashi - Maskawa mixing. These models usually imply mixing effects in the supersymmetric scalar sector. We construct the fermion and scalar mass matrices in two viable models, and calculate the mixing effects on the $\mu \to e\gamma$, $\mu \to 3 e$ and $\tau \to \mu\gamma$ rare decays. The relevant constraints on the sparticle mass spectrum as well as the role of various MSSM parameters are discussed.Comment: 14 pages, 1 figure included in the ps file, uses epsfig.st

Generalized Additive Modelling of Mixed Distribution Markov Models with Application to Melbourne's Rainfall.

We consider modelling time series using a generalized additive model with first- order Markov structure and mixed transition density having a discrete component at zero and a continuous component with positive sample space. Such models have application, for example, in modelling daily occurrence and intensity of rainfall, and in modelling the number and size of insurance claims. We show how these methods extend the usual sinusoidal seasonal assumption in standard chain- dependent models by assuming a general smooth pattern of occurrence and intensity over time. These models can be fitted using standard statistical software. The methods of Grunwald and Jones (1998) can be used to combine these separate occurrence and intensity models into a single model for amount. We use 36 years of rainfall data from Melbourne, Australia, as a vehicle of illustration, and use the models to investigate the effect of the El Nino phenomenon on Melbourne's rainfall.Time Series ; Econometric Models ; Mixed Distribution Markov Models

Loop transfer matrix and gonihedric loop diffusion

We study a class of statistical systems which simulate 3D gonihedric system on euclidean lattice. We have found the exact partition function of the 3D-model and the corresponding critical indices analysing the transfer matrix $K(P_{i},P_{f})$ which describes the propagation of loops on a lattice. The connection between 3D gonihedric system and 2D-Ising model is clearly seen.Comment: 14 pages, Late

Oxygen isotope composition of the primitive Achondrites

Primitive achondrites provide a record of the earliest stages of asteroidal melting. A detailed study of their oxygen isotope variation shows that these meteorites retain significant levels of primary oxygen isotope heterogeneity