The growth factor parametrization versus numerical solutions in flat and non-flat dark energy models

In the present investigation we use observational data of $f \sigma_ {8}$ to determine observational constraints in the plane $(\Omega_{m0},\sigma_{8})$ using two different methods: the growth factor parametrization and the numerical solutions method for density contrast, $\delta_{m}$. We verified the correspondence between both methods for three models of accelerated expansion: the $\Lambda CDM$ model, the $w_{0}w_{a} CDM$ model and the running cosmological constant $RCC$ model. In all case we consider also curvature as free parameter. The study of this correspondence is important because the growth factor parametrization method is frequently used to discriminate between competitive models. Our results we allow us to determine that there is a good correspondence between the observational constrains using both methods. We also test the power of the $f\sigma_ {8}$ data to constraints the curvature parameter within the $\Lambda CDM$ model. For this we use a non-parametric reconstruction using Gaussian processes. Our results show that the $f\sigma_ {8}$ data with the current precision level does not allow to distinguish between a flat and non-flat universe

APT - evidencia empírica en el análisis del ROA en una empresa de servicios públicos domiciliarios de acueducto y alcantarillado

Con la metodología APT desarrollada por ROSS, se evaluó la Rentabilidad del Activo - ROA para una empresa de servicios públicos domiciliarios de acueducto y alcantarillado del departamento antioqueño. El sector de los servicios públicos domiciliarios de aguas es de naturaleza monopólica y el método de valoración del costo de capital empleado para determinar las tarifas de las empresas que participan en éste, se encuentra regulado por un órgano del Estado colombiano. Este trabajo pretende evaluar una alternativa diferente o complementaria al método CAPM empleado por el regulador, para encontrar el costo de capital que refleje las características de este mercado en Colombia. Para lograrlo, en este artículo se incorpora el método de componentes principales como medio de reducción de 19 variables observadas que se agrupan en diversas categorías: macroeconómicas, financieras y técnico operativas de la empresa analizada. A partir de los datos se modelo el ROA, estableciéndose de los resultados alcanzados que cinco componentes determinan la rentabilidad del activo de la empresa analizada, destacándose de ellas la cobertura geográfica y el rendimiento Operativo.Using methodology developed by ROSS, the Return on Assets - ROA was assessed for a firm of public utilities for water and sewer department of Antioquia. The public utilities sector of water is monopolistic nature and the method of valuation of the cost of capital used to determine the rates of the companies involved in this, is regulated by an agency of Colombia. This paper evaluates a different or complementary alternative to the CAPM method used by the regulator to find the cost of capital that reflects the characteristics of this market in Colombia. For achieving this goal, in this paper the method of principal components is incorporated, reducing 19 observed variables that are classified into various categories: macroeconomic, financial, technical and operating of the company studied. From the data, it was established the results achieved in five components that determine the profitability of the assets of the company analyzed, highlighting the geographical coverage and operational performance

Exact inflationary solutions

We present a new class of exact inflationary solutions for the evolution of a universe with spatial curvature, filled with a perfect fluid, a scalar field with potential $V_{\pm}(\phi)=\lambda(\phi^2\pm\delta^2)^2$ and a cosmological constant $\Lambda$. With the $V_+(\phi)$ potential and a negative cosmological constant, the scale factor experiments a graceful exit. We give a brief discussion about the physical meaning of the solutions.Comment: 10 pages, revtex file, 6 figures included with epsf. To be published in IJMP-

Caracterización físico-química y microbiológica de la miel de Apis mellifera sp. del Suroeste de Antioquia, Colombia

Characterizations of Apis mellifera honey produced in Southwest of Antioquia, an important coffee region of Colombia, have not been published in recent years. In the present work, seven samples of honey collected in the mentioned region, were physically (refractive index, specific rotation, density), chemically (moisture content, water activity, pH, free acidity, carbohydrates) and microbiologically (Clostridium, fungi and yeast) analyzed. The results show that the analyzed honeys meet both national (Resolución 1057 of 2010) and International (Codex-Stan 12 of 1981) standards for moisture content, free acidity, sucrose content and microbiological parameters, indicating their good quality. Fructose/glucose ratio, pH and specific rotation values indicate that the samples are blossom honeys.Caracterizaciones de miel de Apis mellifera producida en el Suroeste de Antioquia, una región cafetera de Colombia, no se han publicado recientemente. En el presente trabajo, siete muestras de miel recolectadas en la región mencionada, fueron físicamente (índice de refracción, rotación específica, densidad), químicamente (contenido de humedad, actividad acuosa, pH, acidez libre, carbohidratos), y microbiológicamente (Clostridium, hongos y levaduras) analizadas. Los resultados muestran que las mieles analizadas cumplen tanto los estándares nacionales (Resolución 1057 de 2010) como internacionales (Codex-Stan 12 de 1981) para contenido de humedad, acidez libre, contenido de sacarosa y los parámetros microbiológicos, indicando su buena calidad. Los valores de relación fructosa/glucosa, pH y rotación específica indican que las muestras son mieles florales

Caracterización físico-química y microbiológica de la miel de Apis mellifera sp. del Suroeste de Antioquia, Colombia

Characterizations of Apis mellifera honey produced in Southwest of Antioquia, an important coffee region of Colombia, have not been published in recent years. In the present work, seven samples of honey collected in the mentioned region, were physically (refractive index, specific rotation, density), chemically (moisture content, water activity, pH, free acidity, carbohydrates) and microbiologically (Clostridium, fungi and yeast) analyzed. The results show that the analyzed honeys meet both national (Resolución 1057 of 2010) and International (Codex-Stan 12 of 1981) standards for moisture content, free acidity, sucrose content and microbiological parameters, indicating their good quality. Fructose/glucose ratio, pH and specific rotation values indicate that the samples are blossom honeys.Las caracterizaciones de la miel de Apis mellifera producida en el suroeste de Antioquia, una importante región cafetera de Colombia, no se han publicado en los últimos años. En el presente trabajo, siete muestras de miel recolectadas en la región mencionada fueron física (índice de refracción, rotación específica, densidad), químicamente (contenido de humedad, actividad del agua, pH, acidez libre, carbohidratos) y microbiológicamente (Clostridium, hongos y levaduras ) analizado. Los resultados muestran que las mieles analizadas cumplen con los estándares nacionales (Resolución 1057 de 2010) e internacionales (Codex-Stan 12 de 1981) para el contenido de humedad, acidez libre, contenido de sacarosa y parámetros microbiológicos, lo que indica su buena calidad. La relación fructosa / glucosa, el pH y los valores de rotación específicos indican que las muestras son mieles en flor

Tablero de control para el seguimiento y evaluación de las políticas públicas

In Colombia, public policies are designed that must be articulated with the Development Plans and Comprehensive Plans for Security and Citizen Coexistence (PISCC) at the Municipal, Departmental and National levels. There is concern at the national level because these policies are not normally monitored or evaluated, or if they are carried out they do so in a very elementary way. Corporate Governance seeks to establish guidelines to achieve the strategic direction of the organization; this is to verify the fulfillment of its objectives, to make an adequate risk management and an optimization of the resources. Territorial entities, more than any other organization, must strive for the fulfillment of their objectives, plans, programs and projects, facilitating the monitoring of the execution of public resources, at the same time that they adequately manage their risks. This dashboard tool allows the monitoring and evaluation of the plans and programs proposed within the PISCC, under the eye of IT Government as a control mechanism of public policies.En Colombia se diseñan Políticas Públicas que deben estar articuladas con los Planes de Desarrollo y Planes Integrales de Seguridad y Convivencia Ciudadana (PISCC) a nivel Municipal, Departamental y Nacional. Existe una preocupación a nivel nacional porquenormalmente no se hace un monitoreo ni evaluación a dichas políticas o si se realizan lo hacen de forma muy elemental. El GobiernoCorporativo busca establecer lineamientos para lograr el direccionamiento estratégico de la organización; esto es verificar el cumplimiento desus objetivos, hacer una adecuada gestión de riesgos y una optimización de los recursos. Los entes territoriales, más que cualquier otraorganización deben propender por el cumplimiento de sus objetivos, planes, programas y proyectos, facilitando el seguimiento a la ejecuciónde los recursos públicos, a la vez que gestionan adecuadamente sus riesgos. Esta herramienta de tablero de control permite el monitoreo yevaluación de los planes y programas planteados dentro de los PISCC, bajo una mirada de Gobierno de TI como un mecanismo de control delas políticas públicas

Role of Nanoclays in Carbon stabilization in Andisols and Cambisols

Greenhouse gas (GHG) emissions and their consequent effect on global warming are an issue of global environmental concern. Increased carbon (C) stabilization and sequestration in soil organic matter (SOM) is one of the ways to mitigate these emissions. Here we evaluated the role of nanoclays isolated from soil on C stabilization in both a C rich Andisols and C depleted Cambisols. Nanoclays were analyzed for size and morphology by transmission electron microscopy, for elemental composition and molecular composition using pyrolysis-GC/MS. Moreover, nanoclays were treated with H2O2 to isolate stable SOM associated with them. Our result showed better nanoclay extraction efficiency and higher nanoclay yield for Cambisol compared to Andisols, probably related to their low organic matter content. Nanoclay fractions from both soils were different in size, morphology, surface reactivity and SOM content. Nanoclays in Andisols sequester around 5-times more C than Cambisols, and stabilized 6 to 8-times more C than Cambisols nanoclay after SOM chemical oxidation. Isoelectric points and surface charge of nanoclays extracted from the two soils was very different. However, the chemical reactivity of the nanoclay SOM was similar, illustrating their importance for C sequestration. Generally, the precise C stabilization mechanisms of both soils may be different, with nanoscale aggregation being more important in Andisols. We can conclude that independent of the soil type and mineralogy the nanoclay fraction may play an important role in C sequestration and stabilization in soil-plant systems

Hybrid loss exceedance curve (HLEC) for disaster risk assessment

Taken into account that the natural hazard risk is a contingent liability and, therefore, a sovereign risk for national governments, it is important to assess properly the potential losses to design a suitable risk reduction, retention and transfer strategy. In this article, a disaster risk assessment methodology is proposed based on two approaches: on the one hand, the empiric estimation of losses, using information available from local disaster databases, allowing estimating losses due to small-scale events and, on the other hand, probabilistic evaluations to estimate losses for greater or even catastrophic events, for which information usually is not available due to the lack of historical data. A ‘‘hybrid’’ loss exceedance curve is thus determined, which combines the results of these two approaches and represents the disaster risk in a proper and complete way. This curve merges two components: the corresponding to small and moderate losses, calculated using an inductive and retrospective analysis, and the corresponding to extreme losses, calculated using a deductive and prospective analysis. Applications of this risk assessment technique are given in this article for eleven countries

The fermionic contribution to the spectrum of the area operator in nonperturbative quantum gravity

The role of fermionic matter in the spectrum of the area operator is analyzed using the Baez--Krasnov framework for quantum fermions and gravity. The result is that the fermionic contribution to the area of a surface $S$ is equivalent to the contribution of purely gravitational spin network's edges tangent to $S$. Therefore, the spectrum of the area operator is the same as in the pure gravity case.Comment: 10 pages, revtex file. Revised versio