Diffusion at the liquid-vapor interface

Recently, the intrinsic sampling method has been developed in order to obtain, from molecular simulations, the intrinsic structure of the liquid-vapor interface that is presupposed in the classical capillary wave theory. Our purpose here is to study dynamical processes at the liquid-vapor interface, since this method allows tracking down and analyzing the movement of surface molecules, thus providing, with great accuracy, dynamical information on molecules that are "at" the interface. We present results for the coefficients for diffusion parallel and perpendicular to the liquid-vapor interface of the Lennard-Jones fluid, as well as other time and length parameters that characterize the diffusion process in this system. We also obtain statistics of permanence and residence time. The generality of our results is tested by varying the system size and the temperature; for the later case, an existing model for alkali metals is also considered. Our main conclusion is that, even if diffusion coefficients can still be computed, the turnover processes, by which molecules enter and leave the intrinsic surface, are as important as diffusion. For example, the typical time required for a molecule to traverse a molecular diameter is very similar to its residence time at the surface.Comment: 25 pages, 7 figures. Submitted to J. Chem. Phy

Admixture in Latin America

Latin Americans arguably represent the largest recently admixed populations in the world. This reflects a history of massive settlement by immigrants (mostly Europeans and Africans) and their variable admixture with Natives, starting in 1492. This process resulted in the population of Latin America showing an extensive genetic and phenotypic diversity. Here we review how genetic analyses are being applied to examine the demographic history of this population, including patterns of mating, population structure and ancestry. The admixture history of Latin America, and the resulting extensive diversity of the region, represents a natural experiment offering an advantageous setting for genetic association studies. We review how recent analyses in Latin Americans are contributing to elucidating the genetic architecture of human complex traits

Propuesta de fortalecimiento del modelo organizacional y la creación de valor compartido en empresas beneficiarias del programa Fondo Emprender de la ciudad de Villavicencio durante el periodo 2015 - 2018

Diseñar una propuesta de fortalecimiento del modelo organizacional a partir del análisis de la Cadena de Valor Compartido y Modelo empresarial del siglo XXI de cuatro empresas ganadoras de Fondo Emprender de la ciudad de Villavicencio durante el periodo 2015 – 2018La presente investigación consistió en la elaboración de una propuesta para el fortalecimiento del modelo organizacional y la creación de valor compartido en cuatro empresas beneficiarias del Fondo Emprender SENA, durante el periodo de tiempo comprendido entre los años 2015 al 2018 en la ciudad de Villavicencio Meta. Se trató de un estudio descriptivo transversal con enfoque cualitativo, cuya finalidad fue identificar las características internas de estas empresas mediante una encuesta semiestructurada. Dichas organizaciones se escogieron de una base de datos de compañías proporcionada por Fondo Emprender, en las cuales se identificó la configuración en aspectos tales como: el modelo organizacional, funciones de los órganos administrativos, procesos generales, facultades delegadas al personal, canales de comunicación y la creación de valor compartido. Tras el diagnóstico se propusieron alternativas para el mejoramiento en los procesos organizacionales y administrativos de las empresas partícipes en el estudio. De igual modo se entregaron sugerencias a Fondo Emprender SENA para apoyo a futuros participantes del programa.This research consisted in the development of a proposal for the strengthening of the organizational model and the creation of shared value in four beneficiary companies of the Fondo Emprender SENA, during the period of time between the years 2015 to 2018 in the city of Villavicencio Meta. It was a descriptive cross-sectional study with a qualitative approach, the purpose of which was to identify the internal characteristics of these companies through a semi structured survey. Said organizations were chosen from a database of companies provided by Fondo Emprender, in which the configuration was identified in aspects such as: the organizational model, unctions of the administrative bodies, general processes, powers delegated to the staff, communication channels and creating shared value. After the diagnosis, alternatives were proposed to improve the organizational and administrative processes of the companies participating in the study. In the same way, uggestions were given to Fondo Emprender SENA to support future participants of the program

DISEÑO DE UN SISTEMA DE RECONOCIMIENTO DE ROSTROS MEDIANTE LA HIBRIDACIÓN DE TÉCNICAS DE RECONOCIMIENTO DE PATRONES, VISIÓN ARTIFICIAL E IA, ENFOCADO A LA SEGURIDAD E INTERACCIÓN ROBÓTICA SOCIAL

Este artículo presenta el diseño, desarrollo y la implementación de desarrollo de un sistema de reconocimiento de rostros mediante la hibridación de técnicas de reconocimientos de patrones, visión artificial e inteligencia artificial. La presente investigación recopila el producto de la unión de las técnicas de visión artificial y las técnicas de inteligencia artificial y sus implicaciones en múltiples aplicaciones tales como el control de robots de interacción social

The role of seasonality in shaping the interactions of honeybees with other taxa

The Eltonian niche of a species is defined as its set of interactions with other taxa. How this set varies with biotic, abiotic and human influences is a core question of modern ecology. In seasonal environments, the realized Eltonian niche is likely to vary due to periodic changes in the occurrence and abundance of interaction partners and changes in species behavior and preferences. Also, human management decisions may leave strong imprints on species interactions. To compare the impact of seasonality to that of management effects, honeybees provide an excellent model system. Based on DNA traces of interaction partners archived in honey, we can infer honeybee interactions with floral resources and microbes in the surrounding habitats, their hives, and themselves. Here, we resolved seasonal and management-based impacts on honeybee interactions by sampling beehives repeatedly during the honey-storing period of honeybees in Finland. We then use a genome-skimming approach to identify the taxonomic contents of the DNA in the samples. To compare the effects of the season to the effects of location, management, and the colony itself in shaping honeybee interactions, we used joint species distribution modeling. We found that honeybee interactions with other taxa varied greatly among taxonomic and functional groups. Against a backdrop of wide variation in the interactions documented in the DNA content of honey from bees from different hives, regions, and beekeepers, the imprint of the season remained relatively small. Overall, a honey-based approach offers unique insights into seasonal variation in the identity and abundance of interaction partners among honeybees. During the summer, the availability and use of different interaction partners changed substantially, but hive- and taxon-specific patterns were largely idiosyncratic as modified by hive management. Thus, the beekeeper and colony identity are as important determinants of the honeybee's realized Eltonian niche as is seasonality

Effects of oral prednisone administration on serum cystatin C in dogs

ANTECEDENTES La administración oral de glucocorticoides altera la concentración sérica de cistatina C (sCysC) en humanos. OBJETIVO Determinar si la administración oral de prednisona altera la sCysC en perros sin enfermedad renal preexistente. Los animales Se incluyeron cuarenta y seis perros: 10 perros diagnosticados con meningitis arterial esteroide sensible (SRMA; grupo A), 20 perros diagnosticados de hiperadrenocorticismo hipofisario-dependiente (PDH; grupo B) y 16 perros control sanos (grupo C). Metodos Estudio observacional retrospectivo. A los perros diagnosticados con SRMA se les administró prednisona 4 mg / kg / 24 h PO 7 días, reduciendo la dosis a 2 mg / kg / 24 h 7 días antes del retiro de la medicación. En el grupo A, el muestreo se realizó en los días 0, 7, 14 y un control final en el día 21. Se recogieron muestras de sangre y orina en los 3 grupos, y en el grupo A, el muestreo se realizó en todos los puntos de tiempo (días 1, 7). , 14, y 21). RESULTADOS En el grupo A, sCysC fue significativamente mayor en el día 7 en comparación con el grupo de control (0,4 ± 0,04 mg / l vs. 0,18 ± 0,03 mg / l medio ± SEM respectivamente P 0.05). Los perros con PDH incluidos en el grupo B no tuvieron diferencias significativas en sCysC (0.22 ± 0.03 mg / L) en comparación con el control (P> 0.05). CONCLUSIONES Y IMPORTANCIA CLÍNICA La administración oral de prednisona, a diferencia de la producción alterada de glucocorticoides endógenos, aumenta la sCysC en perros de una manera dependiente de la dosis.BACKGROUND Oral administration of glucocorticoid alters serum cystatin C (sCysC) concentration in humans. OBJECTIVE To determine if oral administration of prednisone alters sCysC in dogs without pre‐existing renal disease. ANIMALS Forty six dogs were included: 10 dogs diagnosed with steroid responsive meningitis arteritis (SRMA; group A), 20 dogs diagnosed of pituitary‐dependent hyperadrenocorticism (PDH; group B), and 16 healthy control dogs (group C). METHODS Retrospective observational study. SRMA diagnosed dogs were administered prednisone 4 mg/kg/24 h PO 7 days, reducing the dose to 2 mg/kg/24 h 7 days before medication withdrawal. In group A, sampling was performed at days 0, 7, 14 and a final control at day 21. Blood and urine samples were collected in the 3 groups, and in group A, sampling was performed at all time points (days 1, 7, 14, and 21). RESULTS In group A, sCysC was significantly higher at day 7 compared to the control group (0.4 ± 0.04 mg/L vs. 0.18 ± 0.03 mg/L mean ± SEM respectively P 0.05). Dogs with PDH included in group B did not have significant differences in sCysC (0.22 ± 0.03 mg/L) compared to control (P > 0.05). CONCLUSIONS AND CLINICAL IMPORTANCE Oral administration of prednisone unlike altered endogenous glucocorticoid production, increases sCysC in dogs in a dose‐dependent fashion.• Ministerio de Economía y Competitividad. Beca Juan de la Cierva IJCI-2014-19428, para Beatriz Macías GarcíapeerReviewe

Genetic components of human pain sensitivity: a protocol for a genome-wide association study of experimental pain in healthy volunteers

Introduction Pain constitutes a major component of the global burden of diseases. Recent studies suggest a strong genetic contribution to pain susceptibility and severity. Whereas most of the available evidence relies on candidate gene association or linkage studies, research on the genetic basis of pain sensitivity using genome-wide association studies (GWAS) is still in its infancy. This protocol describes a proposed GWAS on genetic contributions to baseline pain sensitivity and nociceptive sensitisation in a sample of unrelated healthy individuals of mixed Latin American ancestry. Methods and analysis A GWAS on genetic contributions to pain sensitivity in the naïve state and following nociceptive sensitisation will be conducted in unrelated healthy individuals of mixed ancestry. Mechanical and thermal pain sensitivity will be evaluated with a battery of quantitative sensory tests evaluating pain thresholds. In addition, variation in mechanical and thermal sensitisation following topical application of mustard oil to the skin will be evaluated. Ethics and dissemination This study received ethical approval from the University College London research ethics committee (3352/001) and from the bioethics committee of the Odontology Faculty at the University of Antioquia (CONCEPTO 01–2013). Findings will be disseminated to commissioners, clinicians and service users via papers and presentations at international conferences

Variantes en los genes TNFA, IL6 e IFNG asociadas con la gravedad del dengue en una muestra de población colombiana

Introduction: The genetic makeup of the host contributes to the clinical profile of dengue. This could be due to the effect of variants in the genes encoding pro-inflammatory cytokines.Objective: To evaluate the association between the variants of three polymorphisms in TNFA, IL6 and IFNG candidate genes with dengue severity in a sample of Colombian population.Materials and methods: We evaluated the rs1800750, rs2069843, and rs2069705 polymorphisms in TNFA, IL6 and IFNG candidate genes, respectively, in 226 patients with dengue infection. The genotypes were typed using both polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). To determine the risk of different dengue phenotypes, we compared allele frequencies with chi-square and genotypes and haplotypes using logistic regression. Finally, these analyzes were adjusted with data from self-identification or the ancestral genetic component.Results: The A allele in the rs2069843 polymorphism, adjusted by self-identification, was associated with dengue hemorrhagic fever cases in Afro-Colombians. In the entire sample, this polymorphism, adjusted by the ancestral genetic component, was reproducible. In addition, there were significant associations between GGT and GAC allelic combinations of rs1800750, rs2069843, and rs2069705 in dengue hemorrhagic fever patients, with and without adjustment by ancestral genetic component. Additionally, the AGC allelic combination produced 58.03 pg/ml of interleukin-6 more than the GGC combination, regardless of European, Amerindian and African genetic components.Conclusions: The variants of GGT and GAC polymorphisms of rs1800750, rs2069843, and rs2069705 in the TNFA, IL6 and IFNG genes, respectively, were correlated with the susceptibility to dengue severity in a sample of Colombian population.Introducción. La composición genética del huésped determina, entre otros aspectos, el perfil clínico del dengue, lo cual se debería al efecto de variantes en los genes que codifican citocinas proinflamatorias.Objetivo. Evaluar la asociación entre las variantes de tres polimorfismos en los genes candidatos TNFA, IL6 e IFNG con la gravedad del dengue en una población colombiana.Materiales y métodos. Se evaluaron los polimorfismos rs1800750, rs2069843 y rs2069705 de los genes TNFA, IL6 e IFNG, respectivamente, en 226 pacientes con dengue. Los genotipos se tipificaron usando la reacción en cadena de la polimerasa (PCR) y los polimorfismos de la longitud de los fragmentos de restricción (Restriction Fragment Length Polymorphism, RFLP). Para determinar el riesgo de diferentes fenotipos del dengue, se compararon las frecuencias alélicas con la prueba de ji al cuadrado, y los genotipos y los haplotipos, con regresión logística. Por último, los análisis se ajustaron utilizando datos de autoidentificación o del componente genético ancestral.Resultados. El alelo A del rs2069843, ajustado por autoidentificación, se asoció con casos de dengue hemorrágico en afrocolombianos. En la muestra completa, dicho polimorfismo, ajustado por componente genético ancestral, fue reproducible. Además, hubo asociaciones significativas entre las combinaciones alélicas GGT y GAC de los rs1800750, rs2069843 y rs2069705 en pacientes con dengue hemorrágico, con ajuste por componente genético ancestral y sin él. Además, la combinación alélica AGC produjo 58,03 pg/ml más de interleucina 6 que la GGC, independientemente de los componentes genéticos europeo, amerindio y africano.Conclusión. Las variantes de los polimorfismos GGT y GAC de los rs1800750, rs2069843 y rs2069705 en los genes TNFA, IL6 e IFNG, respectivamente, se correlacionaron con la gravedad del dengue en esta muestra de población colombiana