Self-dual formulations of d=3 gravity theories in the path-integral framework

We study the connection, at the quantum level, between d=2+1 dimensional self-dual models with actions of growing (from first to fourth) order, governing the dynamics of helicity +2 (or -2) massive excitations. We obtain identities between generating functionals of the different models using the path-integral framework, this allowing to establish dual maps among relevant vacuum expectation values. We check consistency of these v.e.v.'s with the gauge invariance gained in each mapping.Comment: 26 pages. LaTeX. Minor changes. Published in Int. J Modern Phys. A; http://www.worldscinet.com/ijmp

The Ciao clp(FD) library. A modular CLP extension for Prolog

We present a new free library for Constraint Logic Programming over Finite Domains, included with the Ciao Prolog system. The library is entirely written in Prolog, leveraging on Ciao's module system and code transformation capabilities in order to achieve a highly modular design without compromising performance. We describe the interface, implementation, and design rationale of each modular component. The library meets several design goals: a high level of modularity, allowing the individual components to be replaced by different versions; highefficiency, being competitive with other TT> implementations; a glass-box approach, so the user can specify new constraints at different levels; and a Prolog implementation, in order to ease the integration with Ciao's code analysis components. The core is built upon two small libraries which implement integer ranges and closures. On top of that, a finite domain variable datatype is defined, taking care of constraint reexecution depending on range changes. These three libraries form what we call the TT> kernel of the library. This TT> kernel is used in turn to implement several higher-level finite domain constraints, specified using indexicals. Together with a labeling module this layer forms what we name the TT> solver. A final level integrates the CLP (J7©) paradigm with our TT> solver. This is achieved using attributed variables and a compiler from the CLP (J7©) language to the set of constraints provided by the solver. It should be noted that the user of the library is encouraged to work in any of those levels as seen convenient: from writing a new range module to enriching the set of TT> constraints by writing new indexicals

Evolución del conocimiento físico

In this paper we wish to present the evolution of the structure of the physic knowledge from the level of 1st year BUP to science graduates. The reliability of the responses also analysed

Potenciales aplicaciones de películas de quitosano en alimentos de origen animal: una revisión

En la actualidad se ha observado un incremento constante del número de intoxicaciones y muertes humanas alrededor del mundo debido a la contaminación de los alimentos de origen animal con patógenos perjudiciales para la salud. Es por esto que varias tecnologías se han investigado, desarrollado y aplicado para mejorar la inocuidad alimentaria. Dentro de estos métodos cabe mencionar la utilización de bioembalajes con polímeros naturales con una alta actividad antimicrobiana, como el quitosano,obtenido a partir de la desacetilación alcalina de la quitina. El quitosano presenta una gran variedad de propiedades biológicas como biodegradabilidad, biocompatibilidad, baja toxicidad, actividad antimicrobiana de amplio espectro, y capacidad de formación de películas comestibles. Esto lo convierten en un biomaterialatractivo para aplicaciones biotecnológicas e industriales. Un ejemplo de esto son las películas de quitosano,que hansido probadas en conservación de alimentos y la tecnología de envasado, ya que exhiben una alta actividad contra patógenos, como hongos, levaduras,bacterias Gram-positivas y negativas, disminuyendo el deterioro de los alimentos de origen animal y vegetal. Este artículo revisa las potenciales aplicaciones del quitosano debido a su acción antimicrobiana sobre los principales patógenos que afectan la inocuidad de los productos de origen animal como carne, cecinas, embutidos, leche, huevos, queso, pescado y mariscos, que repercuten en la mejora de la calidad y el aumento de la vida útil de éstos productos.  

Adults with sedentary lifestyle, overweight, obesity and the risk of developing obstructive sleep apnea hypoapnea syndrome in a sample of the Ecuadorian population

Overweight, obesity, and a sedentary lifestyle have been associated with poor sleep quality, which includes obstructive sleep apnea-hypoapnea syndrome. The objective of this research was to relate sedentary lifestyle, overweight, and obesity as risk factors for developing obstructive sleep apnea-hypoapnea syndrome in a sample of Ecuadorian adults. For this research, adults over 18 years of age belonging to 17 provinces of Ecuador were considered as the study population, the non-probability sampling technique was used for convenience, and different questionnaires were used for data collection: Berlin questionnaire was used to evaluate the risk of obstructive sleep apnea-hypoapnea syndrome, Epworth sleepiness questionnaire for the study of sleep quality, as well as the IPAQ international physical activity questionnaire. Among the most important results, 61.4% women, 95.2% mestizos, 47.8% people were those who performed high physical activities, 82.4% resided in the urban areas. Participants with normal weight predominated, 57.7%. It was found that 10.3% of the surveyed population presents a high risk of suffering from obstructive sleep apnea-hypoapnea syndrome. When relating it to the physical activity variable, it was observed that sedentary people have 17.3% of suffering from the syndrome of obstructive sleep apnea-hypoapnea, when relating to overweight and obesity we found 10.85% and 63.6%, respectively. These differences were statistically significant p < 0.05. In conclusion, the risk of obstructive sleep apnea-hypoapnea syndrome was related to sedentary, overweight, and obese people. Keywords: obstructive sleep apnea-hypopnea syndrome sedentary lifestyle, physical activity, overweight, obesity. Resumen En los últimos años se ha asociado al sobrepeso, obesidad y sedentarismo como causas de una mala calidad del sueño que han provocado enfermedades como el síndrome de apneahipoapnea obstructiva del sueño. El objetivo de la investigación fue relacionar el sedentarismo, sobrepeso y obesidad como factores de riesgo para desarrollar el síndrome de apneahipoapnea obstructiva del sueño en una muestra de personas adultas ecuatorianas. Para la investigación se tomó como población de estudio a personas adultas mayores de 18 años pertenecientes a 17 provincias del Ecuador, se utilizó la técnica de muestreo no probabilístico por conveniencia, para la recolección de datos se utilizó diferentes cuestionarios: cuestionario de Berlín que evalúa el riesgo de padecer síndrome de apnea-hipoapnea obstructiva del sueño, cuestionario de somnolencia de Epworth para el estudio de la calidad del sueño y el cuestionario internacional de actividad física IPAQ. Entre los resultados más importantes se resalta mujeres 61,4%, mestizos 95,2%, personas que realizan actividades físicas altas 47,8%, residen en la zona urbana 82,4%. Predominaron los participantes con normopeso 57,7%. Se encontró que el 10,3% de la población encuestada presenta riesgo alto de padecer síndrome de apnea-hipoapnea obstructiva del sueño, al relacionar con la variable de actividad física se pudo observar que las personas sedentarias tienen un 17,3% de padecer síndrome de apneahipoapnea obstructiva del sueño, al relacionar con el sobrepeso y obesidad encontramos el 10,85% y 63,6% respectivamente, estas diferencias fueron estadísticamente significativas p<0,05. En conclusión, el riesgo de padecer el síndrome de apnea-hipoapnea obstructiva del sueño se relacionó con las personas con sedentarismo, sobrepeso y obesidad. Palabras Clave: Síndrome de Apnea-Hipoapnea Obstructiva del Sueño, SAHOS, Actividad Física, Sobrepeso, Obesidad

Magnetic structure and orbital ordering in BaCoO3 from first-principles calculations

Ab initio calculations using the APW+lo method as implemented in the WIEN2k code have been used to describe the electronic structure of the quasi-one-dimensional system BaCoO3. Both, GGA and LDA+U approximations were employed to study different orbital and magnetic orderings. GGA predicts a metallic ground state whereas LDA+U calculations yield an insulating and ferromagnetic ground state (in a low-spin state) with an alternating orbital ordering along the Co-Co chains, consistent with the available experimental data.Comment: 8 pages, 9 figure

Comparison of price between a healthy and unhealthy diet in the Metropolitan Region, Chile

Indexación: Scopus; Scielo.Obesity remains a serious public health problem worldwide and in Latin America. The implementation of dietary guidelines is a strategy used in Chile and other Latin-American countries to promote healthy eating habits. Evidence from studies in US and Europe suggests that healthy eating patterns have a higher price compared to unhealthy food options. However, this has not been evaluated in Chile. Our goal was to compare the price and relation to energetic density of a healthy diet (HD) that follows the Chilean dietary with an unhealthy diet (UD) in the Metropolitan Region (MR), the most densely populated demographical division in Chile. The HD was obtained from the publication "Cocinasaludable: comoincluir 5 porciones de frutas y verduras por dia", a book of recipessponsored by theChilean governmentto promote intake of fruits and vegetables that fulfills the Chilean dietary guidelines. The UD was obtained by replacing recipesand food items from the DS with processed foods and recipes typically consumed in Chile. The price database was compiled from databases of the Chilean Government and on-line retailers at MR. The UD has higher energy density, has higher energy from fats and a lower healthy eating index compared with the HD. Price analysis indicated an inverse relation between caloric density and price for food groups and that the UD has an overall lower price compared to the HD. Our results suggest that the higher price of a HD in compliance with the Chilean dietary guidelines could hinder their implementation in the MR, and the transition towards healthy eating habits among its population.http://www.scielo.org.ve/scielo.php?script=sci_arttext&pid=S0004-0622201600040000

A joint time-dependent density-functional theory for excited states of electronic systems in solution

We present a novel joint time-dependent density-functional theory for the description of solute-solvent systems in time-dependent external potentials. Starting with the exact quantum-mechanical action functional for both electrons and nuclei, we systematically eliminate solvent degrees of freedom and thus arrive at coarse-grained action functionals which retain the highly accurate \emph{ab initio} description for the solute and are, in principle, exact. This procedure allows us to examine approximations underlying popular embedding theories for excited states. Finally, we introduce a novel approximate action functional for the solute-water system and compute the solvato-chromic shift of the lowest singlet excited state of formaldehyde in aqueous solution, which is in good agreement with experimental findings.Comment: 11 page

The theoretical overview of the regional economy and patterns of spatial analysis

Una gran parte de la teoría económica clásica se construyó sin tomar en consideración la variable espacio. En general, los enfoques se han basado esencialmente en el mercado, planteando la movilidad de los factores de producción, y de los bienes y servicios producidos, sin tener en cuenta si el territorio donde se dan facilita, dificulta o incluso impide su circulación, o si la serie de características y elementos ligados al territorio favorece la concentración de riqueza en determinadas áreas o dificulta el desarrollo de las mismas. En las últimas cuatro décadas, la consideración de este elemento se ha ido imponiendo progresivamente dentro de la planeación económicaThe vast majority of elements belonging to the classical economic theory was constructed without taking into account geographical or space variables. In general, these approaches have been based essentially on the market, raising the mobility of factors of production and goods and services produced, regardless of geographical considerations. This optic makes difficult to foresee economics movements, or economic links among actors which in turn result in concentration of wealth in specific areas, covered by a similar degree of development. In the last four decades, consideration of this element has been gradually imposing within the sphere of economic plannin