Earnings Mobility in Argentina, Mexico, and Venezuela: Testing the Divergence of Earnings and the Symmetry of Mobility Hypotheses

This paper examines changes in individual earnings during positive and negative growth periods in three Latin American economies: Argentina, Mexico, and Venezuela. We ask whether those individuals who start in the best economic position are those who experience the largest earnings gains or the smallest earnings losses; this is the “divergent mobility” hypothesis. We also compare periods of positive economic growth with those of negative economic growth, asking whether those groups of individuals that experience large positive earnings gains when the economy is growing are the same as those that experience large earnings losses when the economy is contracting; this is the “symmetry of mobility” hypothesis. We find very occasional support for the divergent mobility hypothesis in scattered years in the cases of Mexico and Venezuela, and no support at all in the case of Argentina. Rather, earnings mobility is most frequently convergent or neutral in all three countries. As for the symmetry of mobility hypothesis, we find that it is rejected in most cases; rather, those groups that gain the most when the economy is growing are also the ones that gain the most when the economy is contracting. Furthermore, we explain how the absence of divergence is compatible with rising inequality in the countries under study

Income Mobility in Latin America

[Excerpt] In the last decades Latin American countries have experienced substantial macroeconomic instability. While the region as a whole experienced economic growth during most of the 1990’s and 2000’s, there were also years of stagnation as well as economic decline

La investigación escolar en la construcción de explicaciones acerca de la transmisión de caracteres hereditarios. sistematización de la unidad didáctica ¡moscas!... a enseñar herencia

El presente trabajo expondrá el desarrollo significativo respecto a conceptos, procedimientos y actitudes referidos a la herencia de caracteres hereditarios, que alcanzaron los estudiantes del grado octavo del IEDIT Rodrigo de Triana, en un periodo de tres meses en el año 2008, durante el cual se ejecutó el diseño, aplicación y sistematización de la unidad didáctica ¡Moscas! a enseñar herencia. En esta experiencia educativa se adoptaron los postulados del Enfoque de Enseñanza por Investigación Dirigida y el instrumento metodológico de Investigación Acción, donde los estudiantes organizados en equipos de trabajo abordaron una pregunta problema para desarrollar una investigación escolar, bajo la atenta dirección de las docentes, quienes corroboraron un cambio procedimental, conceptual y actitudinal en los estudiantes del grado 803

A New Simulated Annealing Algorithm for the Multiple Sequence Alignment Problem: The approach of Polymers in a Random Media

We proposed a probabilistic algorithm to solve the Multiple Sequence Alignment problem. The algorithm is a Simulated Annealing (SA) that exploits the representation of the Multiple Alignment between $D$ sequences as a directed polymer in $D$ dimensions. Within this representation we can easily track the evolution in the configuration space of the alignment through local moves of low computational cost. At variance with other probabilistic algorithms proposed to solve this problem, our approach allows for the creation and deletion of gaps without extra computational cost. The algorithm was tested aligning proteins from the kinases family. When D=3 the results are consistent with those obtained using a complete algorithm. For $D>3$ where the complete algorithm fails, we show that our algorithm still converges to reasonable alignments. Moreover, we study the space of solutions obtained and show that depending on the number of sequences aligned the solutions are organized in different ways, suggesting a possible source of errors for progressive algorithms.Comment: 7 pages and 11 figure

Electrical properties of individual tin oxide nanowires contacted to platinum electrodes

A simple and useful experimental alternative to field-effect transistors for measuring electrical properties free electron concentration nd, electrical mobility , and conductivity in individual nanowires has been developed. A combined model involving thermionic emission and tunneling through interface states is proposed to describe the electrical conduction through the platinum-nanowire contacts, fabricated by focused ion beam techniques. Current-voltage I-V plots of single nanowires measured in both two- and four-probe configurations revealed high contact resistances and rectifying characteristics. The observed electrical behavior was modeled using an equivalent circuit constituted by a resistance placed between two back-to-back Schottky barriers, arising from the metal-semiconductor-metal M-S-M junctions. Temperature-dependent I-V measurements revealed effective Schottky barrier heights up to BE= 0.4 eV

Graphite Oxide: A Simple and Reproducible Synthesis Route

The synthesis of graphite oxide (GrO) by oxidation of graphite has been carried out by different procedures. In this chapter, we describe a simple synthesis route based on Hummers’ method without the usage of NaNO3 achieving nearly the same outcomes, and this methodology is directed toward high-quality scale production of GrO with similar properties compared with GrO obtained with traditional and improved Hummers’ methods. The GrO was obtained in a series of batch reactions and characterized by different techniques, and the results showed identical interlayer d-space, type and content of oxygen functionalities, and ID/IG ratio. The high reproducibility of this methodology offers an efficient alternative for the large-scale production of graphene oxide