812 research outputs found

    Testing Core Membership in Public Goods Economies

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    This paper develops a recent line of economic theory seeking to understand public goods economies using methods of topological analysis. Our first main result is a very clean characterization of the economy's core (the standard solution concept in public goods). Specifically, we prove that a point is in the core iff it is Pareto efficient, individually rational, and the set of points it dominates is path connected. While this structural theorem has a few interesting implications in economic theory, the main focus of the second part of this paper is on a particular algorithmic application that demonstrates its utility. Since the 1960s, economists have looked for an efficient computational process that decides whether or not a given point is in the core. All known algorithms so far run in exponential time (except in some artificially restricted settings). By heavily exploiting our new structure, we propose a new algorithm for testing core membership whose computational bottleneck is the solution of O(n)O(n) convex optimization problems on the utility function governing the economy. It is fairly natural to assume that convex optimization should be feasible, as it is needed even for very basic economic computational tasks such as testing Pareto efficiency. Nevertheless, even without this assumption, our work implies for the first time that core membership can be efficiently tested on (e.g.) utility functions that admit "nice" analytic expressions, or that appropriately defined ε\varepsilon-approximate versions of the problem are tractable (by using modern black-box ε\varepsilon-approximate convex optimization algorithms).Comment: To appear in ICALP 201

    Techno-economic analysis of integrating sweet sorghum into sugar mills: The Central American case

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    This paper aims to evaluate the potential for electricity and ethanol production in Central America using sweet sorghum, performing a techno-economic analysis. The study proposes the integration of sweet sorghum into Central American sugar mills, by using the existing machinery to process this crop during off-season. A process simulation and a cost model were developed to estimate the technical and economical feasibility of sweet sorghum integration. The data on various parameters used for techno-economic assessment were collected from an existing sugar mill and distillery in Central America. The results show that a sugar mill operating 2 months during off-season could obtain an average revenue of US3Mforacrushingrateof6500t/d.Ethanolproductioncostsareestimatedtobe24.76¢US 3 M for a crushing rate of 6500 t/d. Ethanol production costs are estimated to be 24.76 ¢US/L. In case a new CHP plant is built, a sugar mill operating under the integrated scenario would have a payback period of 4.49 years, as compared to 7.47 years for a sugar mill using sugarcane bagasse as the only fuel. Although several studies highlight the potential of sweet sorghum for ethanol production, the results from this work prove that sweet sorghum must also be seen as a viable feedstock for electricity production. A sensitivity analysis was also performed to determine the variation of the average cost of electricity and ethanol with the variables used in the economic analysis. For all analysed scenarios the effects of installed capacity and crop yield prevailed over the increasing costs of land and transportation.Publicad

    Running Successful Extension Camps for Hispanic Children: From Program Planning to Program Delivery for a 1-Week Day Camp

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    To address the increasing Hispanic population in Illinois and to follow the mission of the University of Illinois Extension, educators must find ways to reach this population. To serve the Hispanic population with non-bilingual staff, it is necessary to address how to plan and deliver a camp, what support is need for non-bilingual Extension personnel, and whether Extension can meet the needs of this population. An evaluation of a summer camp for Spanish-speaking children was conducted. The results of this evaluation demonstrated that Extension programs could be effectively carried out in Hispanic communities with little modification

    Walking into History: Holocaust History and Memory on the March of the Living

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    This thesis is an ethnography of how children of Holocaust survivors interacted and connected with the March of the Living and Holocaust sites in Poland. This work explores how considering individual perspectives allows one to understand how the March works in complicated and nuanced ways to intensify connections with relatives and Jewish identity. In three chapters this work situates the experiences of four participants within theories of place-making and post-memory to consider methods they used to connect with Holocaust sites and what effect that connection had on their sense of identity

    Impact of a 4-H Youth Development Program on At-Risk Urban Teenagers

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    Dynamic programs that integrate science literacy and workforce readiness are essential to today\u27s youth. The program reported here combined science literacy (gardening and technology) with workforce readiness to assess the impact of program type, prior program participation, and behavior/punctuality on knowledge gain. Findings show that past participation in a similar program positively impacted knowledge gain. Further, the results indicate that behavior/punctuality also increased knowledge gain. Of particular interest to Extension educators, this article discusses the implications of examining only mean scores to assess program effectiveness, especially where prior programs have been attended by students

    Fundamentos básicos sobre conceptos y herramientas utilizadas en el área DevOps

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    Proporcionar un conjunto de herramientas y conceptos relacionados al área de DevOps e implementaciones en la nube para todo estudiante de ingeniería en ciencias y sistemas interesado que desea iniciar su recorrido en esta rama del campo laboral, así facilitar el acceso a ejemplos de diferentes herramientas utilizadas en automatizaciones de hoy en día y persuadir a nuevas generaciones a involucrase en temas relacionados a la nube

    Beneficios de la culminación del nivel primario en las madres de familia: Estudio realizado en el Barrio Patzité, del municipio de Momostenango, departamento de Totonicapán.

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    A pesar del indudable progreso que ha alcanzado la situación de las mujeres durante las últimas décadas, en cuestiones de educaciónaún sigue siendo uno de los mayores problemas que están aquejando a la sociedad. Tienen que lidiar con obstáculos a veces insuperable para poder y terminar un ciclo formativo completo. La educación en las mujeres es de suma importancia porque sin esto en un futuro pueden llegar a tener dificultades en el desarrollo personal y familiar; debido a que no tienen la formación apropiada para desenvolverse en los distintos ámbitos y suelen ser discriminadas a causa del analfabetismo; con respecto a su hogar, se les dificulta dirigir adecuadamente y son más propensas a sufrir violencia intrafamiliar, por eso cuando tienen los conocimientos básicos, adquieren beneficios que les ayuda a ser mejores personas ante la sociedad y la familia que llegan a formar. Pero se vive dentro de un contexto que poseen ideas erróneas, respecto a que las mujeres no tienen necesidad de la educación, esto por la ideología que la misma sociedad ha adquirido donde consideran que los hombres son más inteligentes, que ellas han nacido para quedarse en la casa al cuidado de los hijos e hijas y del hogar. Que al realizar estas actividades no necesitan de estudios, entre distintas opiniones y prejuicios que se transmiten a otras generaciones perjudicando de forma radical. Es fundamental que se cambie la manera de pensar, para ello es necesario aprender a distinguir la realidad con una mirada crítica y no pasiva. Hasta cierto punto se tiene razón en que las mujeres son las indicadas de velar por la familia porque los hijos se sienten más allegados a las madres desde el nacimiento, aquí se ve la importancia de tener conocimientos para atender adecuadamente a los niños, conociendo las necesidades que tienen y así contribuir al crecimiento y su desarrollo físico, intelectual, emocional, entre otros

    La formación ciudadana en el contexto educativo de los estudiantes de tercer grado del ciclo básico: Estudio realizado en Institutos Nacionales de Educación Básica de los municipios de: Totonicapán, San Cristóbal Totonicapán, San Francisco El Alto y Momostenango del departamento de Totonicapán.

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    La investigación se enfoca en el tema de la formación ciudadana en el contexto educativo de los estudiantes de tercer grado del ciclo básico. Lo que ha implicado un compromiso en el trabajo de formar a educandos que respondan a las necesidades de su comunidad, para que sean capaces de actuar correctamente en el proceso de toma de decisiones, en la responsabilidad democrática y en la participación ciudadana, como algunos de los derechos y obligaciones que todo ciudadano debe practicar en la sociedad teniendo el objetivo de lograr la convivencia pacífica. Es necesario analizar la importancia de la formación ciudadana y el impacto positivo que se obtiene al desarrollar en el estudiante estas habilidades, la influencia y el papel estratégico que tiene el docente en la enseñanza y el aprendizaje. La metodología aplicada en la investigación es descriptiva-analítica porque el contenido está relacionado con el comportamiento de cada estudiante según el aprendizaje significativo que ha obtenido desde su formación ciudadana en el ciclo básico y en el contexto educativo. Fueron 172 estudiantes encuestados para obtener diversas opiniones. Como resultado, se ha detectado que la participación en la toma de decisiones de la vida cotidiana tanto en el aula como en el establecimiento es muy reducida, ya que regularmente solo lo hacen los educandos activos y participativos fenómeno que se sitúa en varios centros educativos. En consecuencia, se requiere de estrategias participativas para su formación, en la escuela y en el hogar para que se puedan demostrar con acciones la influencia y la enseñanza adquirida. Los catedráticos deben tomar un papel fundamental en los procesos de enseñanza-aprendizaje; darle especial énfasis a los estándares de la formación ciudadana y sobre todo poder contar con el apoyo de los padres de familia. Estas acciones permitirán que el estudiante desarrolle habilidades, construya competencias, forme aspiraciones, gane en seguridad y descubra recursos valiosos

    Pulmonary neuroendocrine cells in neonatal rats with congenital diaphragmatic hernia

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    Lung hypoplasia and persistent pulmonary hypertension are the principal causes of high mortality and morbidity in infants with congenital diaphragmatic hernia (CDH). Amine-and peptide-producing pulmonary neuroendocrine cells (PNEC), widely distributed throughout the airway mucosa, are thought to play an important role in both pulmonary development and regulation of pulmonary vascular tone. Furthermore, recent studies show increased levels of calcitonin gene-related peptide (CGRP), a pulmonary vasodilator produced by PNEC, during chronic hypoxia. The article reports data on morphometric analysis of CGRP immunoreactive PNEC clusters (neuroepithelial bodies, NEB) in a rat model of CDH. CDH was induced in neonatal Sprague Dawley rats by oral administration of 2,4-dichloro-phenyl- p-nitro-phenylether (Nitrofen; Rohm Haas, Philadelphia, PA) to the mother at 10 days of gestation. Sections of lungs from term neonatal rats with and without CDH and controls were immunostained for CGRP (marker of NEB) with specific antibody against rat CGRP. NEB size and number of NEB/area of lung were assessed using a semiautomatic image analysis system. In lungs of neonatal rats with CDH, the number of NEB per surface area of lung parenchyma was significantly increased compared with the age-matched controls. Although the mean size of NEB was larger in CDH, the differences were not significant. This is the first study of PNEC in CDH. Whether the phenomenon observed in this study results in altered NEB function including imbalance in vasoactive mediators requires further studies, especially in the human being

    Calcitonin gene-related peptide expression is altered in pulmonary neuroendocrine cells in developing lungs of rats with congenital diaphragmatic hernia

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    Congenital diaphragmatic hernia (CDH) is associated with high neonatal mortality from lung hypoplasia and persistent pulmonary hypertension. Pulmonary neuroendocrine cells (PNEC) produce calcitonin gene-related peptide (CGRP), a potent vasodilator. We previously reported altered distribution of CGRP-positive PNEC in full-term rats with CDH, that may lead to an imbalance in vasoactive mediators. In the present study we examined the expression of CGRP-positive PNEC during lung development in rats with CDH induced by 2,4-dichlorophenyl-p-nitrophenylether (Nitrofen). Cesarean sections were performed on Days 16, 18, 20, or 22, and the lungs were immunostained for CGRP and immunoreactive cells were quantitated through image analysis. On Day 16, CGRP-immunoreactive staining was negative; on Day 18, CGRP-immunoreactive cells were found in all controls (not exposed to Nitrofen), whereas in CDH pups, CGRP-positive cells were present in only four of six cases. On Day 20, CGRP immunoreactivity was similar in CDH pups, Nitrofen-exposed pups without CDH, and controls. On Day 22 (term), significantly more CGRP-positive cells (i.e., number of positive cells per surface area [mm2] or lung volume [mm3]) were found in ipsilateral lungs of CDH pups than in controls (P < 0.05). The difference was even more striking in contralateral lungs of CDH pups (P < 0.001), ruling out nonspecific effects of Nitrofen. In CDH lungs, the proportion of immunostained epithelium and the size of the neuroendocrine cell clusters (neuroepithelial bodies [NEB]) were not significantly different from those of controls. On Day 22, supraoptimal dilution immunocytochemistry yielded similar results in CDH pups and controls. We conclude that in CDH, CGRP expression in PNEC and NEB is delayed during early stages of lung development. Because CGRP also exhibits growth factor-like properties for endothelium and epithelial cells, the lack of this factor during a crucial developmental stage (canalicular period) may be causally related to lung hypoplasia
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