Ahstract-Optimal operation of hydrothermal systems is very complex hecause it corresponds to a mnltiperiod, stochastic, large scale and characterized hy a nonseparable objective function optimization problem As a result it is traditionally carried out without taking into account transmission constraints or considering them in n very simplified wny. This approach is not adequate lo address certain kind of problems such as cost-benefit studies of transmission interconnections in hydro systems or the study of spatial distributions of spot prices ("zones" identification) through the electric network, due to hydro and power flow constraints. In this paper we address the problem of stochastic optimization of large scale transmission constrained hydrothermal systems with applications to the Brazilian case.

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introduction: The cause of the sudden infant death syndrome (SIDS) is perhaps the oldest of unsolved mysteries of medicine, possibly dating back to Exodus in Biblical times when Egyptian children died in their sleep as if from a plague. It occurs when infants die unexpectedly with no sufficient cause of death found in a forensic autopsy, including death scene investigation and review of medical history. That SIDS is an X-linked recessive death from infectious respiratory disease of a physiologically anemic infant and not a simple anomalous cardiac or neurological condition is an extraordinary claim that requires extraordinary evidence. If it were by a simple cause, it would have already been solved, with over 11,000 papers on SIDS listed now in PubMed. Our aim is to use mathematical models of SIDS to explain: (1) its 50% excess male death rate; (2) its 4-parameter lognormal distribution of ages at death; (3) its winter maxima and summer minima; and (4) its increasing rate with live-birth order.Methods: From extensive SIDS vital statistics data and published epidemiologic studies, we developed probability models to explain the mathematical behavior of SIDS meeting the four constraints mentioned above. We, then, compare these SIDS properties to infant death from acute respiratory infection (ARI), and infant death from encephalopathy, unspecified (EU).results: Comparisons show that SIDS are congruent with ARI and are not consistent with EU and that these probability models not only fit the SIDS data but they also predict and fit the male fraction of all infant and child mortality from birth through the first 5 years of their life.conclusion: SIDS are not rejected as an X-linked disease involving ARI and are not explained by a triple risk model that has been commonly accepted by the SIDS medical community, as implicating a neurological causation process in a subset of SIDS.

Although the association between acculturation and substance use among Latino groups is important, it is often understudied, especially within specific Latino groups living in geographically distinct communities, such as the Mexican American population in South Texas. The researchers of this study aimed to better understand the effect of acculturation on substance use and alcohol dependence in a Mexican American college student population. This survey study investigated the correlation between acculturation and substance use and dependence by using the Vancouver Index of Acculturation (VIA), items related to substance use (nicotine, marijuana, and cocaine) in a Mexican American college student sample (N = 1,494), and the Short Alcohol Dependence Data Questionnaire (SADD; N = 715). The study was conducted in the Texas-Mexico border region. The results suggest that higher levels of acculturation do not predict increased drug use or alcohol dependence in the Mexican American college students. However, acculturation was found to be associated with lower use of cocaine and marijuana. The discussion examines commonalities and differences in drug use and dependence. Specifically, acculturation seems to have an inverse relationship to substance use and may serve as a protective factor to licit and illicit drug use among Mexican American college students.

El objetivo de la investigación fue analizar las diferencias entre el rendimiento académico y el tipo de práctica artística extracurricular en estudiantes de bachillerato. Participaron 169 estudiantes de la ciudad de Morelia, Michoacán (México). Se recabaron datos sociodemográficos mediante una ficha de identificación; se diseñó y aplicó un Inventario de Actividades Académicas y Extra Académicas (actividad artística entre ellas) y se obtuvo la boleta de calificaciones de cada participante; los datos se analizaron con el programa SPSS 20. Se llevaron a cabo pruebas de diferencia entre las variables: rendimiento académico y tipo de práctica artística. Se encontraron diferencias estadísticamente significativas entre el rendimiento académico y la práctica de las artes, siendo los participantes que practican actividades artísticas los de mejor rendimiento académico, sobre todo en las asignaturas de Español y Literatura.

Abstract:Introduction: The Sudden Infant Death Syndrome (SIDS) is not likely to be explained by a currently measureable presence in all cases and absence in controls, as otherwise it would have been solved already. Indeed, any proposed physiological model for SIDS causation must explain the constant mathematical and statistical properties of SIDS age and gender. We have shown previously that SIDS are characterized by a common 4-parameter lognormal age distribution sparing neonatal infants, by a nominal 50% male excess, and by a higher rate in winter than summer. We test now whether SIDS is closely related to a fulminating prodromal Acute Respiratory Infection (ARI) by a common increasing rate with the infants increasing Live Birth Order (LBO), all remaining the same, independent of the change in preferred sleeping positions of the infants, prone or supine. Methods: We use U.S. published infant mortality data from wonder.cdc.gov and other countries (Colombia, U.K., Europe, Australasia) to make comparisons between the two causes of death (ARI and SIDS) to evaluate how closely ARI resembles the characteristics of SIDS. Results: Gender: SIDS male excess 50%, ARI male excess 50%; Ages: SIDS 90% post-neonatal, ARI 96% post-neonatal; Seasonality: SIDS and ARI are higher in winter than summer; Live birth order: SIDS and ARI rates increase with increasing LBO with similar mathematical relationship. Conclusion: Our results show that all SIDS are very likely relatable to a single cause tied to a fulminating prodromal ARI in a physiologically anemic infant who is genetically (X-link recessive) susceptible to cerebral anoxia. An alternative cause of all SIDS death by a collection of subsets of different causes, such as brainstem-related respiratory abnormalities and cardiac QT abnormalities, is not supported because they cannot all have the same age-gender-seasonal-familial-distributions of SIDS, required by Cramér's Theorem.

El aprendizaje de la lectoescritura es un logro primordial que plantea todo sistema educativo, constituye un prerrequisito importante en el desarrollo de habilidades cognitivas complejas que permiten a las personas hacer frente a exigencias de la vida cotidiana. Este estudio parte de la idea de que en el desarrollo de dicho aprendizaje las interacciones en la casa y en la escuela desempeñan un papel decisivo, por lo que se propuso analizar las creencias que madres de familia y docentes formulan respecto de la educación preescolar y cómo estas influyen en el desarrollo de habilidades para la lectoescritura y la competencia lectora. Mediante un abordaje cualitativo, se describe el punto de vista de los participantes respecto a la finalidad de la Educación Preescolar y sobre la manera en que esta la involucra. Los hallazgos permiten afirmar que la visión del jardín de niños como espacio de entretenimiento y cuidado ha sido superada; sin embargo, respecto a los procesos de lectoescritura existe confusión y una tendencia a reducirlos simplemente a la decodificación. Finalmente, el estudio destaca la importancia de identificar y desarrollar modelos que favorezcan estos procesos y se discute la necesidad de que las madres de familia colaboren corresponsablemente para asegurar el acceso y participación exitosa en iniciativas que impulsen el desarrollo de habilidades para la lectoescritura

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