Desarrollo de un modelo de caracterización financiera del sector comercio en Ecuador, período 2002-2012

Caracterizar financieramente al sector comercial ecuatoriano involucra el investigar las principales variables macroeconómicas y financieras inmersas dentro del sector, para lo cual, se partió de la hipótesis de que el sector comercial ecuatoriano tiene un determinado desempeño financiero que se puede caracterizar a través de la construcción de un modelo estadístico. Se inició con la búsqueda de información sobre el desarrollo de modelos estadísticos similares, en tres países (Alemania, México y Chile), sin embargo, en la web superficial no se obtuvo un modelo a seguir pues únicamente se han estructurado modelos utilizando variables macroeconómicas. Por ello, se diseñó un modelo estadístico basado en el método de mínimos cuadrados ordinarios. La base de datos empleada corresponde al formulario 101 “impuesto a la renta de sociedades y establecimientos permanentes” del Servicio de Rentas Internas (SRI). El modelo estadístico trabaja con un nivel de confianza del 95%, existen once observaciones (período 2002-2012), siete variables independientes (exportaciones netas, inventario de materia prima y productos terminados, total costos y gastos, total ingresos, total pasivo, total patrimonio neto y ventas netas locales totales excluye activos fijos) que explican el comportamiento de la variable dependiente (utilidad del ejercicio). Se realizaron las pruebas de hipótesis correspondientes, presentando consistencia en los resultados encontrados. También se realizó la predicción del comportamiento de la variable dependiente por un período, la misma que difirió en 7,1% del valor real, lo que se explica por el limitado número de observaciones. Se construyeron dos escenarios (pesimista y optimista), asignándoles una probabilidad de ocurrencia, con lo que se calculó el valor esperado (US $ 3.727 millones) y la desviación estándar (US $ 4.842 millones). La investigación se compone de cinco capítulos. El primero, realiza una introducción y aborda la metodología. El segundo, refiere al marco teórico. El tercer capítulo, caracteriza estadística y financieramente al sector comercial ecuatoriano. En el cuarto capítulo se evalúan los efectos de la construcción del modelo utilizando el análisis de escenarios y de elasticidad. Mientras que el quinto capítulo recoge las conclusiones, observaciones y recomendaciones de la investigación.

Modelo de gestión de riesgos en proyectos de inversión de la Subsecretaría de Energía Renovable del Ministerio de Electricidad y Energía Renovable

La gestión del riesgo durante un largo periodo, ha sido vista de manera ausente en la política pública del Estado. Es por ello que en la actualidad, la nueva visión de la gestión integral de los riesgos en las Entidades del Gobierno se orientan a una política de Estado que responde a la necesidad de prevenir, mitigar y establecer un plan de contingencias ante la presencia de estos. En el caso del presente documento se analizará la planificación integral de gestión de riesgos para los proyectos: Minicentral Hidroeléctrica y Biomasa – Aceite Piñón, dando énfasis en el análisis cuantitativo a través de la elaboración de la viabilidad financiera, a fin de establecer herramientas que contribuyan a determinar la sostenibilidad y sustentabilidad en la ejecución de proyectos en el Sector Eléctrico La temática se constituye en seis capítulos. En el primer capítulo se presenta una reseña del sector eléctrico, sus funciones y atribuciones dentro del Gobierno Central, así también el objetivo del documento para el manejo de la gestión de riesgos en este nivel. El segundo capítulo detalla el ámbito legal bajo el cual se rige el sector eléctrico en cuanto a gestión de riesgos se refiere. El tercer capítulo muestra la estructura orgánica funcional del Ministerio de Electricidad y Energía Renovable y su cumplimiento con la misión, visión y objetivos institucionales. El cuarto capítulo se refiere al análisis y comparación del marco teórico de las metodologías: Project Management Body of Knowledge – PMBOK y Committee of Sponsoring Organizations of The Treadway Commission – COSO a fin de determinar cuál de estas se ajusta a la naturaleza del Sector. El quinto capítulo se centra directamente en la planificación integral de la gestión de riesgos de los proyectos antes mencionados, mostrando su análisis desde la planificación, identificación mediante la cual se registra una lista corta de riesgos, análisis cualitativo en donde se estableció la matriz de probabilidad e impacto de riesgos, análisis cuantitativo efectuado a través de la ejecución del flujo financiero, plan de respuesta y monitoreo y control. El capítulo seis presenta las conclusiones y recomendaciones. Finalmente el capítulo siete detalla la bibliografía utilizada en el presente documento.

Dietary predictors of serum total carotene in low-income women living in Sao Paulo, south-east Brazil

Objective Dietary intake and nutritional status of antioxidant vitamins have been reported to protect against some cancers The objective of the present study was to assess the correlations between serum levels of carotenoids (including beta-, alpha- and gamma-carotene), lycopene, retinol, alpha- and gamma-tocopherols, and dietary intakes estimated by an FFQ, among low-income women in the Brazilian Investigation into Nutrition and Cervical Cancer Prevention (BRINCA) study. Design Cross-sectional study of data for 918 women aged 21-65 years participating in the BRINCA study in Sao Paulo city. Multiple linear regression models were used with serum nutrient levels as the dependent variable and dietary intake levels as the independent variable, adjusted for confounding factors. Results In energy-adjusted analyses, the intakes of dark green and deep yellow vegetables and fruits (partial R(2) = 4.8%), total fruits and juices (partial R(2) = 1.8%), vegetables and fruits (partial R(2) = 1.8%), carrots (partial R(2) = 1.4%) and citrus fruits and juices only (partial R(2) = 0.8%) were positively correlated only with serum total carotene levels, after adjusting for serum total cholesterol concentration, age, hospital attended, smoking status. BMI and presence of cervical lesions Multiple-adjusted serum levels of carotenoids were positively correlated with intake quartiles of dark green and deep yellow vegetables and fruits and total fruits and juices independent of smoking status. Conclusions The intake of specific fruits and vegetables was an independent predictor of serum total carotene levels in low-income women living in Sao Paulo

Geoelectric evidence for centripetal resurge of impact melt and breccias over central uplift of Araguainha impact structure

We present five profiles from electrical resistivity tomography (ERT), with surface constraints and gravity data, in the central uplift of the Araguainha impact structure in central Brazil. The central uplift, the overlying polymict breccias, and decameter-scale impact melt rocks are characterized by contrasting ranges of electrical resistivity. Our resistivity model provides empirical evidence that supports the existing model in which impact melt and breccias resurged toward the crater center in the final stages of the cratering process. On the basis of our results from the first use of ERT in impact cratering studies, we conclude that the deposition and flow of impact melt and breccias over the central uplift were influenced by the geometry of the lithologic boundaries in the central uplift.

Expression of alpha-synuclein is increased in the hippocampus of rats with high levels of innate anxiety

A genomic region neighboring the alpha-synuclein gene, on rat chromosome 4, has been associated with anxiety- and alcohol-related behaviors in different rat strains. In this study, we have investigated potential molecular and physiological links between alpha-synuclein and the behavioral differences observed between Lewis (LEW) and Spontaneously Hypertensive (SHR) inbred rats, a genetic model of anxiety. As expected, LEW rats appeared more fearful than SHR rats in three anxiety models: open field, elevated plus maze and light/dark box. Moreover, LEW rats displayed a higher preference for alcohol and consumed higher quantities of alcohol than SHR rats. alpha-Synuclein mRNA and protein concentrations were higher in the hippocampus, but not the hypothalamus of LEW rats. This result inversely correlated with differences in dopamine turnover in the hippocampus of LEW and SHR rats, supporting the hypothesis that alpha-synuclein is important in the downregulation of dopamine neurotransmission. A novel single nucleotide polymorphism was identified in the 30-untranslated region (3`-UTR) of the alpha-synuclein cDNA between these two rat strains. Plasmid constructs based on the LEW 3`-UTR sequence displayed increased expression of a reporter gene in transiently transfected PC12 cells, in accordance with in-vivo findings, suggesting that this nucleotide exchange might participate in the differential expression of alpha-synuclein between LEW and SHR rats. These results are consistent with a novel role for alpha-synuclein in modulating rat anxiety- like behaviors, possibly through dopaminergic mechanisms. Since the behavioral and genetic differences between these two strains are the product of independent evolutionary histories, the possibility that polymorphisms in the alpha-synuclein gene may be associated with vulnerability to anxiety- related disorders in humans requires further investigation. Molecular Psychiatry (2009) 14, 894-905; doi: 10.1038/mp.2008.43; published online 22 April 2008

Crop rotation scheduling with adjacency constraints

In this article we propose a 0-1 optimization model to determine a crop rotation schedule for each plot in a cropping area. The rotations have the same duration in all the plots and the crops are selected to maximize plot occupation. The crops may have different production times and planting dates. The problem includes planting constraints for adjacent plots and also for sequences of crops in the rotations. Moreover, cultivating crops for green manuring and fallow periods are scheduled into each plot. As the model has, in general, a great number of constraints and variables, we propose a heuristics based on column generation. To evaluate the performance of the model and the method, computational experiments using real-world data were performed. The solutions obtained indicate that the method generates good results.

Sustainable vegetable crop supply problem

We consider an agricultural production problem, in which one must meet a known demand of crops while respecting ecologically-based production constraints. The problem is twofold: in order to meet the demand, one must determine the division of the available heterogeneous arable areas in plots and, for each plot, obtain an appropriate crop rotation schedule. Rotation plans must respect ecologically-based constraints such as the interdiction of certain crop successions, and the regular insertion of fallows and green manures. We propose a linear formulation for this problem, in which each variable is associated with a crop rotation schedule. The model may include a large number of variables and it is, therefore, solved by means of a column-generation approach. We also discuss some extensions to the model, in order to incorporate additional characteristics found in field conditions. A set of computational tests using instances based on real-world data confirms the efficacy of the proposed methodology. (C) 2009 Elsevier B.V. All rights reserved.

Trypanosoma cruzi MSH2: Functional analyses on different parasite strains provide evidences for a role on the oxidative stress response

Components of the DNA mismatch repair (MMR) pathway are major players in processes known to generate genetic diversity, such as mutagenesis and DNA recombination. Trypanosoma cruzi, the protozoan parasite that causes Chagas disease has a highly heterogeneous population, composed of a pool of strains with distinct characteristics. Studies with a number of molecular markers identified up to six groups in the T. cruzi population, which showed distinct levels of genetic variability. To investigate the molecular basis for such differences, we analyzed the T. cruzi MSH2 gene, which encodes a key component of MMR, and showed the existence of distinct isoforms of this protein. Here we compared cell survival rates after exposure to genotoxic agents and levels of oxidative stress-induced DNA in different parasite strains. Analyses of msh2 mutants in both T. cruzi and T. brucei were also used to investigate the role of Tcmsh2 in the response to various DNA damaging agents. The results suggest that the distinct MSH2 isoforms have differences in their activity. More importantly, they also indicate that, in addition to its role in MMR, TcMSH2 acts in the parasite response to oxidative stress through a novel mitochondrial function that may be conserved in T. brucei. (C) 2010 Elsevier B.V. All rights reserved.