Estado de México y democracia en los albores del siglo XXI

En este capítulo, que se divide en tres apartados principales, se presenta un marco conceptual que, pensamos, tiene importancia en sí mismo, aunque también ha tenido la utilidad práctica de orientar la elaboración e interpretación de la encuesta sobre la calidad de la democracia en el Estado de México que se incluye en este mismo libro

Análisis de Interacciones en Clases de Español de Primer Grado de Primaria

Este trabajo aborda la interacción profesor-alumnos en una clase de español en cuatro grupos escolares de primer grado de primaria de México, a partir de videos. Cada video fue segmentada en episodios interactivos que fueron analizados con categorías únicas estructuradas tanto para el maestro como para el alumno, según la taxonomía funcional de Ribes y López (1985): interacciones contextuales, suplementarias, selectoras, sustitutivas referenciales y sustitutivas no referenciales, y dos categorías de seguimiento didáctico. En general, en el primer grado se estructuran mayormente interacciones en el nivel funcional más sencillo, seguido por interacciones de instrucciones de seguimiento y realimentación. Asimismo, aunque en menor proporción, en dos de los cuatro grupos se presentaron interacciones en niveles funcionales más complejos

Composition and properties of tectosilicate-uranium layers of soil

Structure and superficial properties of tectosilicates found in soils with potential to retain uranium are studied in this work. These tectosilicates are largely available as natural minerals in the soil and are composed mainly by anorthite (CaAl2Si2O8), albite (NaAlSi3O8) and orthoclase (KAlSi3O8), in which albite has approximately 3 times the content of orthoclase and 2.5 times the content of anorthite. However, anorthite has a double cell structure, which could result in approximately the same sorption effect as albite. The acidity constants calculated with the surface complexation model suggested that the three components have similar amphoteric behavior in presence of high ionic strength ground salt solutions. The composite mineral has a specific surface area of 20.5 m2g-1 with site density of 2.8 sites nm-2. These characteristics make this mineral a good candidate for uranium capture

Kinetics of Transesterification of Safflower Oil to Obtain Biodiesel Using Heterogeneous Catalysis

The kinetics of the transesterification of safflower oil and methanol catalyzed by K2O/NaX was studied and modeled. The influence of the oil-methanol initial molar ratio and amount of catalyst were investigated to achieve a maximum triglycerides conversion (99%) and a final methyl esters content of 94% ± 1. A kineticmodel based on an Eley– Rideal mechanism was found to best fit the experimental data when assuming methanol adsorption as determining step. Other models derived from Langmuir – Hinshelwood – Hougen –Watson (LHHW) mechanisms were rejected based on statistical analysis, mechanistic considerations and physicochemical interpretation of the estimated parameters

Stiff Skin Syndrome: Clinical Exploration, Pathophysiology and Therapeutic Advances in a Rare Connective Tissue Disease

Stiff Skin Syndrome, also known as "diffuse stiff skin syndrome" or "Scleroderma-like syndrome with focal contracture", is a rare and complex clinical entity in the spectrum of connective tissue diseases. This disorder is characterized by progressive and diffuse infiltration of connective tissue into the skin and underlying tissues, resulting in extreme skin stiffness and limited joint mobility. In addition to its cutaneous and joint manifestations, stiff skin syndrome can affect multiple internal organs, making it a clinical entity of great multidisciplinary relevance. This article aims to provide a comprehensive review of stiff skin syndrome, addressing its epidemiology, clinical manifestations, etiopathogenesis, differential diagnosis, and current therapeutic options. Recent research that has shed light on the underlying molecular mechanisms and emerging therapies that are being developed to improve the quality of life of patients affected by this disease are highlighted. In addition, the importance of a comprehensive evaluation and an interdisciplinary therapeutic approach to optimize the clinical management of individuals with rigid skin syndrome is highlighted