Path-integral Monte Carlo and the squeezed trapped Bose-Einstein gas

Bose-Einstein condensation has been experimentally found to take place in finite trapped systems when one of the confining frequencies is increased until the gas becomes effectively two-dimensional (2D). We confirm the plausibility of this result by performing path-integral Monte Carlo (PIMC) simulations of trapped Bose gases of increasing anisotropy and comparing them to the predictions of finite-temperature many-body theory. PIMC simulations provide an essentially exact description of these systems; they yield the density profile directly and provide two different estimates for the condensate fraction. For the ideal gas, we find that the PIMC column density of the squeezed gas corresponds quite accurately to that of the exact analytic solution and, moreover, is well mimicked by the density of a 2D gas at the same temperature; the two estimates for the condensate fraction bracket the exact result. For the interacting case, we find 2D Hartree-Fock solutions whose density profiles coincide quite well with the PIMC column densities and whose predictions for the condensate fraction are again bracketed by the PIMC estimates.Comment: 2 pages, 3 figure

A mass transportation approach for Sobolev inequalities in variable exponent spaces

In this paper we provide a proof of the Sobolev-Poincar\'e inequality for variable exponent spaces by means of mass transportation methods. The importance of this approach is that the method is exible enough to deal with different inequalities. As an application, we also deduce the Sobolev-trace inequality improving the result obtained by Fan.Comment: 12 page

Investigación sobre la elaboración de un plan de negocios.

A business plan is a very important tool to analyze the viability of a project or idea of business. Based on this premise, the following document is an investigation of the different elements included in a business plan; every element will be analyzed so that this document may serve as a guide for the elaboration of a business plan.En el presente trabajo se presenta la investigación realizada acerca de los diferentes aspectos que deberán ser incluidos en el plan de negocios. Esta herramienta es fundamental para lograr una empresa o un emprendimiento exitosos ya que recopila información relacionada a diferentes aspectos de una organización para su posterior análisis y por ende determinar la viabilidad de un proyecto o no. La investigación se centró en cada uno de los elementos necesarios para la elaboración del plan de negocios, de tal forma que este documento sirva como guía para realizar este documento escrito

Seguridad humana

Consultable des del TDXA la portada: Programa de doctorado: Seguridad y prevenciónTítol obtingut de la portada digitalitzadaEl objeto de esta tesis es la descripción y el análisis del concepto de seguridad humana. Esta expresión fue utilizada en el informe de 1994 realizado por el Programa de las Naciones Unidas para el Desarrollo(PNUD). Hoy esta noción es empleada por numerosos centros académicos y científicos, por muchas organizaciones internacionales no gubernamentales, por las instituciones del sistema de la Organización de Naciones Unidas, así como por un buen grupo de gobiernos y por la sociedad civil. Se investigan en este trabajo las condiciones y los elementos de un concepto humanocéntrico de la seguridad que se refiere en su sentido más básico a la vida y salud de las personas. Se describen en la misma, las características inherentes a esta nueva dimensión de la seguridad: -La seguridad humana es una preocupación universal. -Los componentes de la seguridad humana son interdependientes. -La seguridad humana tiene un carácter multidimensional. -La prevención es más útil que la intervención posterior para velar por la seguridad humana. Se analizan las siete dimensiones que lo constituyen: Seguridad económica; Seguridad alimentaria; Seguridad en la salud; Seguridad ambiental; Seguridad personal; Seguridad de la comunidad; Seguridad política. Se sostendrá que, a diferencia de los enfoques tradicionales estatocéntricos relacionados con la seguridad, esta investigación explora la idea de que las nuevas amenazas a la seguridad humana son una obstáculo para que las personas puedan poner en funcionamiento sus principales capacidades humanas. El contenido de esta tesis está organizado en torno a cinco capítulos: 1)Seguridad humana: marco conceptual; 2)Cambios en el entorno: interdependencia y vulnerabilidad mutua; 3) Herramientas para la evaluación de la seguridad humana: derechos humanos y enfoque de las capacidades; 4)Seguridad comunitaria y seguridad humana; 5) La seguridad humana y la responsabilidad social de la empresa. Aunque se trata de un concepto amplio y aún en construcción, hay algunos elementos comunes que comparten todas las definiciones que se han analizado. -El cambio en el énfasis, de la seguridad del Estado a la seguridad de las personas. Esta es considerada una de las primeras y principales contribuciones. Desde siglos, la seguridad ha sido definida como la seguridad nacional o como la seguridad del Estado. La seguridad humana ha iniciado el debate sobre las relaciones de la seguridad con las necesidades y los derechos humanos y sobre los nuevos riesgos y peligros producidos por el desarrollo del capitalismo en esta última fase de globalización. -La seguridad humana pone de relieve la interdependencia de la gente en el mundo de hoy demostrando que los problemas no tienen pasaporte, ni se paran en las fronteras nacionales. -Las tareas del Estado, principal responsable de la seguridad, deben ser completadas con iniciativas y acciones de los actores no estatales. La sociedad civil tiene un papel activo en la promoción de la seguridad humana. En muchos casos, estas organizaciones, se han convertido en las principales defensoras efectivas de la misma. Se ha tratado, en suma, de fijar el estado de la ciencia en este campo, desde una metodología interdisciplinar, como paso necesario y previo para continuar las investigaciones futuras en este ámbito. La realidad contemporánea exige la utilización de recursos teóricos y metodológicos, que se orienten hacia una revisión y redefinición de las fronteras entre las disciplinas. Esta tarea conlleva la búsqueda de síntesis y combinaciones alternativas, que permitan, desde una orientación interdisciplinaria, la generación de nuevos conceptos e instrumentos de análisis. Por ello, las ciencias sociales deben sobrepasar las fronteras y promesas del realismo positivista y sustituirlas por un ejercicio crítico que desvele las formas discursivas y las estrategias de poder que vertebran los discursos de las distintas teorías.This thesis describes and analyzes the concept of human security, an expression used in the 1994 United Nations Development Programme (UNDP). Today this idea is used by a number of research and academic centers, by international nongovernmental agencies, by institutional systems of the UN organizations, by many governments and society at large. In this work the conditions and elements of a human-centered concept of security are considered which describe, in very basic terms, people's life and health. Furthermore the inherent characteristics of the new dimension of security is also set out in the following terms: Human security is a universal concern. The components of human security are interdependent. Human security is, by its very nature, multidimensional. Prevention is more useful than subsequent intervention in efforts to ensure human security. The seven dimensions which constitute human security are economic, nutritional, health, personal, community and political. Contrary to an accepted state-centered security focus, this work explores the idea that new threats to human security present an obstacle hindering people from realizing their capacities. The content of this thesis is organized into five chapters: 1) Human security: conceptual framework; 2) changes in its surrounding: interdependence and mutual vulnerability; 3) Tools for assessing human security: human rights and capacities focus; 4) Community and human security; 5) Human security and social responsible in business. Although the concept is wide-ranging and still being developed, there are common elements that share all the definitions under analysis. Changes in emphasis, from State security to personal security. This is considered one of the first and central contributions. - For centuries, security has been defined as national security or State security. Human security has touched off the debate over the relationship between security of needs and human rights and concerning new risks and dangers brought on by the recent development of capitalist globalization. - Human security highlights the interdependence of the people of the world, showing that our problems do not have passports, nor do they stop at national borders. -State security roles, the main agents in this process, must be complemented by initiatives and actions outside the State sector. Civil society has an active role to play in promoting human security. Often, these organizations have become its main defenders. This thesis has, in effect, set out the state of the question in this field, using a multidisciplinary methodology as required and with a view to future research work in this field. Contemporary society demands the use of technical and methodological resources aimed at reviewing and defining the frontiers that separate different disciplines. In this respect there has been an effort here to synthesize and combine alternative tendencies, generate new concepts and instruments of analysis. Thus the social sciences should overcome barriers and promises of positivist realism and substitute them with a critical exercise that reveals discursive forms and power strategies that underpin the discourse of different theories

Alpina: un caso de innovación para la competitividad

Alpina es una compañía pionera en la industria de alimentos en Colombia que se ha desarrollado a partir de la innovación. Este artículo presenta cómo Alpina ha forjado una cultura de innovación, calidad y emprendimiento en todo lo que realiza y cómo los constantes cambios en el contexto competitivo motivan el desarrollo continuo de la capacidad de innovación y estrategias para hacer el negocio más sostenible y con proyección hacia el futuro

Freeze-dried fruit and vegetables useful for agrifood purposes

Lyophilized (freeze-dried) products are food with a long shelf life under storage temperatures above the regular used for food freezing. The manufacture of lyophilized products requires knowledge about the optimum conditions of processing in each vegetable including the right format for any of them. Usually, liophylization, a non-thermal treatment, preserves most of the nutrients and aroma compounds from the original vegetable, particularly when compared with other treatments. The product must to be freezing at around -30oC at the beginning in the same equipment or in other freezer. After that, ice is sublimed in a refrigerated chamber under vacuum and applying a little heat in order to favor water vapor release from the food matrix and then eliminating vapor by condensation at -60oC. Vacuum is a critical step of the process in order to avoid melting ice.Liophylization (freeze-drying) consist in freezing food below -30oC and later removing the ice formed by sublimation in a chamber with controlled temperature under vacuum, and the water vapor produced being removed by condensation at temperatures around -60oC. Different lyophilized products derived from vegetables have been developed that can be used to improved existing foods, to create new ones, or to extract compounds of interest in a food matrix almost free from water. The know-how on liophylization and the problems during the process have been acquired by using pilot equipment. The optimization of the process can be also addressed by calculating the curves of weight loss during drying and the electrical consumption. Quality and safety parameters in fresh and lyophilized product can be also determined compared with the fresh produce. Our main product are freeze-dried samples obtained from a near isogenic line collection of melon derived by classical plant breeding from the ´Piel de sapo´ parental line. This collection rendered products with different taste, flavor, color, etc.The lyophilized product can be stored at -18oC for long periods of time, keeping most of the flavor and taste. The lyophilized can be added as natural food aroma. Lyophilized samples are less sensitive to thawing problems and reduce the cost of transportation because of the lack of water. Technology for liophylization and for storage different kind of vegetable products under vacuum or with modified atmosphere packaging is available in our group

Postharvest technologies to store tropical fruit from the Amazonian Region

Araza is a very perishable fruit particularly at room temperature very rich in vitamin C and with a pleasant flavor. Fruit is also susceptible to wilting, softening, chilling injury (at temperatures below 12oC) and decay (anthracnose). Several combinations of physical postharvest treatments (modified atmosphere packaging, intermittent warming, etc.) have been successfully used to prevent or alleviate these disorders for local markets in Colombia (South America). Our know-how has been partly disseminated as a chapter in the review of the Handbook 66 of the US Department of Agriculture (USDA) (see website below). Arazá fruit is being registered for fresh consumption in the USA, but the fruit is unknown in the Western world. The know-how and expertise background with these fruit can help to develop systematic studies to improve fruit quality and the postharvest system for local market or exports. We are looking for companies interested in supporting our research and apply the postharvest treatments that we developed in a commercial scale for arazá or different fruit from Amazonian.Araza is a very perishable fruit with good nutritive and aromatic value. In the framework of a bilateral agreement between UPCT and SINCHI coordinated by Dr. Hernández -Amazonic Institute for Scientific Research SINCHI, Colombia- and Dr. Fernández-Trujillo -UPCT, Spain- we developed several postharvest treatments to extend araza shelf life and quality. We are looking for a European company with capabilities to introduce araza in the European postharvest system and able to support part of our cooperative research on this fruit (or other Fruit from the Amazonian Region).Arazá fruit can be used for processing and fresh as well as for immediate juice squeezing. The fruit is being registered in the USA for fresh consumption. The product will be exotic in the EU with attractive flavor and nutritive value. Additionally, the fruit is not able to growth outside the rain forest of the Amazonic region or Costa Rica, reason why this fruit can be sold as a typical rain forest productPostharvest technology of fruits and vegetables

A maximal covering location problem based optimization of complex processes : a novel computational approach

Esta tesis basada en artículos analiza un nuevo enfoque computacional para el problema de localización de cobertura máxima (MCLP, sigla en inglés). Consideramos una formulación de tipo difuso del MCLP genérico y desarrollamos los aspectos teóricos y numéricos necesarios del Método de Separación (SM) propuesto. Una estructura específica del MCLP originalmente dado hace posible reducirlo a dos problemas auxiliares de tipo mochila (Knapsack). La separación equivalente que proponemos reduce esencialmente la complejidad de los algoritmos resultantes. Este algoritmo también incorpora una técnica de relajación convencional y el método de escalarización aplicado a un problema auxiliar de optimización multiobjetivo. La metodología de solución propuesta se aplica a continuación a la optimización de la cadena de suministro en presencia de información incompleta. Estudiamos dos ejemplos ilustrativos y realizamos un análisis riguroso de los resultados obtenidos.This Ph.D. article-based thesis discusses a novel computational approach to the extended Maximal Covering Location Problem (MCLP). We consider a fuzzy-type formulation of the generic MCLP and develop the necessary theoretical and numerical aspects of the proposed Separation Method (SM). A speci_c structure of the originally given MCLP makes it possible to reduce it to two auxiliary Knapsack-type problems. The equivalent separation we propose reduces essentially the complexity of the resulting computational algorithms. This algorithm also incorporates a conventional relaxation technique and the scalarizing method applied to an auxiliary multiobjective optimization problem. The proposed solution methodology is next applied to Supply Chain optimization in the presence of incomplete information. We study two illustrative examples and give a rigorous analysis of the obtained results.Doctor en Modelación y Computación CientíficaDoctorad

Fortune or Virtue: Time-Variant Volatilities Versus Parameter Drifting in U.S. Data

This paper compares the role of stochastic volatility versus changes in monetary policy rules in accounting for the time-varying volatility of U.S. aggregate data. Of special interest to us is understanding the sources of the great moderation of business cycle fluctuations that the U.S. economy experienced between 1984 and 2007. To explore this issue, we build a medium-scale dynamic stochastic general equilibrium (DSGE) model with both stochastic volatility and parameter drifting in the Taylor rule and we estimate it non-linearly using U.S. data and Bayesian methods. Methodologically, we show how to confront such a rich model with the data by exploiting the structure of the high-order approximation to the decision rules that characterize the equilibrium of the economy. Our main empirical findings are: 1) even after controlling for stochastic volatility (and there is a fair amount of it), there is overwhelming evidence of changes in monetary policy during the analyzed period; 2) however, these changes in monetary policy mattered little for the great moderation; 3) most of the great performance of the U.S. economy during the 1990s was a result of good shocks; and 4) the response of monetary policy to inflation under Burns, Miller, and Greenspan was similar, while it was much higher under Volcker.DSGE models, Stochastic volatility, Parameter drifting, Bayesian methods