Tensión superficial de las mezclas O2-Ar, N2-Ar y O2-N2-Ar

articulo de investigacionThe surface tension of some binary and ternary mixtures was calculated by means of molecular dynamics simulations in a canonical set. The analyzed mixtures were oxygen-argon, nitrogen-argon and oxygen-nitrogenargon. The force field for argon was recalculated in order to reproduce the experimental surface tension. The corresponding force fields for O2 and N2 were taken from a previous work [Mol. Simul. 45 (2019) 958-966], where it was shown that such force fields reproduce the experimental surface tension curves, as pure fluids. The nitrogen-argon surface tension was calculated for several mole fractions of argon. The obtained curve was compared with those experimental data and a good agreement was found. The standard Lorentz-Berthelot combining rules were employed. For the oxygen-argon mixture it was necessary to modify the cross term of the combining rules in order to reproduce theoretical and experimental data. The surface tension of the ternary mixture was also estimated varying the mole fraction of argon at a certain concentration of oxygen and nitrogen, previously adjusted. Several temperatures were used in order to show a tendency mostly at relatively low temperatures. After comparing the available experimental data, which are scarce, a good agreement was observed

Demographic effects of aggregation in the presence of a component Allee effect

Intraspecific interactions are key drivers of population dynamics because they establish relations between individual fitness and population density. The component Allee effect is defined as a positive correlation between any fitness component of a focal organism and population density, and it can lead to positive density dependence in the population per capita growth rate. The spatial structure is key to determining whether and to which extent a component Allee effect will manifest at the demographic level because it determines how individuals interact with one another. However, existing spatial models to study the Allee effect impose a fixed spatial structure, which limits our understanding of how a component Allee effect and the spatial dynamics jointly determine the existence of demographic Allee effects. To fill this gap, we introduce a spatially-explicit theoretical framework where spatial structure and population dynamics are emergent properties of the individual-level demographic rates. Depending on the intensity of the individual processes the population exhibits a variety of spatial patterns that determine the demographic-level by-products of an existing individual-level component Allee effect. We find that aggregation increases population abundance and allows populations to survive in harsher environments and at lower global population densities when compared with uniformly distributed organisms. Moreover, aggregation can prevent the component Allee effect from manifesting at the population level or restrict it to the level of each independent group. These results provide a mechanistic understanding of how component Allee effects operate for different spatial population structures and show at the population level. Our results contribute to better understanding population dynamics in the presence of Allee effects and can potentially inform population management strategies

Divergent dynamics and the Kauzmann temperature in glass forming systems

In the last decade the challenging analysis of previtreous behavior of relaxation time (Ï.,(T)) in ultraviscous low molecular weight liquids led to the conceptual shift of the glass transition physics toward theories not predicting a finite-temperature divergence. This "breakthrough" experimental finding was strengthened by the discovery that "dynamic "(i.e. from τ(T) fitting) and thermodynamic estimations of the ideal glass (Kauzmann) temperature do not match, what in fact questioned its existence. In this report, due to the novel way of analysis based on the transformation of τ(T) experimental data to the activation energy temperature index form, the clear prevalence of the finite-temperature divergence is proved. The obtained dynamic singular temperatures clearly coincide with thermodynamic estimations of the Kauzmann temperature, thus solving also the second mystery. The comprehensive picture was obtained due to the analysis of 55 experimental data-sets, ranging from low molecular weight liquids and polymers to liquid crystal and plastic crystals

Correlation Function Approach for Estimating Thermal Conductivity in Highly Porous Fibrous Materials

Heat transport in highly porous fiber networks is analyzed via two-point correlation functions. Fibers are assumed to be long and thin to allow a large number of crossing points per fiber. The network is characterized by three parameters: the fiber aspect ratio, the porosity and the anisotropy of the structure. We show that the effective thermal conductivity of the system can be estimated from knowledge of the porosity and the correlation lengths of the correlation functions obtained from a fiber structure image. As an application, the effects of the fiber aspect ratio and the network anisotropy on the thermal conductivity is studied

RNAiFold2T: Constraint Programming design of thermo-IRES switches

Motivation: RNA thermometers (RNATs) are cis-regulatory ele- ments that change secondary structure upon temperature shift. Often involved in the regulation of heat shock, cold shock and virulence genes, RNATs constitute an interesting potential resource in synthetic biology, where engineered RNATs could prove to be useful tools in biosensors and conditional gene regulation. Results: Solving the 2-temperature inverse folding problem is critical for RNAT engineering. Here we introduce RNAiFold2T, the first Constraint Programming (CP) and Large Neighborhood Search (LNS) algorithms to solve this problem. Benchmarking tests of RNAiFold2T against existent programs (adaptive walk and genetic algorithm) inverse folding show that our software generates two orders of magnitude more solutions, thus allow- ing ample exploration of the space of solutions. Subsequently, solutions can be prioritized by computing various measures, including probability of target structure in the ensemble, melting temperature, etc. Using this strategy, we rationally designed two thermosensor internal ribosome entry site (thermo-IRES) elements, whose normalized cap-independent transla- tion efficiency is approximately 50% greater at 42?C than 30?C, when tested in reticulocyte lysates. Translation efficiency is lower than that of the wild-type IRES element, which on the other hand is fully resistant to temperature shift-up. This appears to be the first purely computational design of functional RNA thermoswitches, and certainly the first purely computational design of functional thermo-IRES elements. Availability: RNAiFold2T is publicly available as as part of the new re- lease RNAiFold3.0 at https://github.com/clotelab/RNAiFold and http: //bioinformatics.bc.edu/clotelab/RNAiFold, which latter has a web server as well. The software is written in C++ and uses OR-Tools CP search engine.Comment: 24 pages, 5 figures, Intelligent Systems for Molecular Biology (ISMB 2016), to appear in journal Bioinformatics 201

Correlation Function Analysis of Fiber Networks: Implications for Thermal Conductivity

The heat transport in highly porous fiber structures is investigated. The fibers are supposed to be thin, but long, so that the number of the inter-fiber connections along each fiber is large. We show that the effective conductivity of such structures can be found from the correlation length of the two-point correlation function of the local conductivities. Estimation of the parameters, determining the conductivity, from the 2D images of the structures is analyzed

Xestión Integrada de Pontevedra: innovación para adaptar las ISO 9001 Y 14001

La estrategia de la Xerencia de Xestión Integrada de Pontevedra e O Salnés para adaptarse a las últimas versiones de las Normas ISO 9001 e ISO 14001 destaca por un despliegue original. Para llevar a cabo este proceso de cambio se realizaron actividades de formación y sensibilización, y un despliegue de equipos de consultoría interna y mejora . Esta experiencia podría ser de utilidad para otras organizaciones sanitariasA estratexia da Xerencia de Xestión Integrada de Pontevedra e O Salnés para adaptarse ás últimas versións das Normas ISO 9001 e ISO 14001 destaca por un despregamento orixinal. Para levar a cabo este proceso de cambio realizáronse actividades de formación e sensibilización, e un despregamento de equipos de consultoría interna e mellora . Esta experiencia podería ser de utilidade para outras organizacións sanitaria

Spanish adaptation of the overall anxiety and depression severity and impairment scales in university students

The lifetime prevalence of emotional disorders in Spain is 4.1% for anxiety and 5.2% for depression, increasing among university students. Considering the scarcity of screenings with adequate psychometric properties, this study aims to explore the validity evidence of the Overall Anxiety/Depression Severity and Impairment Scales (OASIS and ODSIS). A total of 382 university students from the general population were assessed on anxiety and depressive symptoms, as well as quality of life. The one-dimensional structure of both the OASIS and ODSIS explained 87.53% and 90.60% of variance, with excellent internal consistency (alpha = 0.94 and 0.95, respectively) and optimal cut-offs of 4 and 5, respectively. Both scales show a significant moderate association with other measures of anxiety, depression and quality of life. The OASIS and ODSIS have shown good reliability and sound validity evidence that recommend their use for the assessment and early detection of anxiety and depressive symptoms, and associated quality of life impairment in Spanish youth

Analisis de operatividad en la caballeriza del Centro de Practicas San Isidro Labrador de la Universidad Nacional Agraria Sede Regional Camoapa, noviembre 2018 a febrero 2019

El presente estudio se realizó en la caballeriza San Isidro Labrador de la Universidad Nacional Agraria Sede Regional Camoapa con el fin de analizar su operatividad. El estudio fue a través de investigación no experimental del tipo descriptiva y bajo el enfoque de sistemas, considerando el esquema: Entradas (recursos), Procesos, Salidas. Se hizo uso de la entrevista informal y la observación para verificación in situ. Esto permitió determinar el estado actual de los recursos utilizados en el sistema; asimismo la descripción del proceso de producción, que garantiza el funcionamiento actual del mismo.Con la información obtenida se procedió a la definición de estrategias de mejoras extraídas de un análisis FODA - DOFA. Los recursos naturales agua y suelo presentan buenas condiciones para el buen abastecimiento a los animales, propiciar su manejo apropiado y ampliación del área de pastos dada las condiciones del suelo; se albergan 23 equinos con edades entre 4 y 15 años, pertenecientes a las razas española, warlander e iberos en condiciones satisfactorias de salud; el área destinada a pastos es de 9.65 ha, con la presencia de pastos Para caribe (Bachiaria mutica) y King Grass (Híbrido entre Penisetum purpureum y Penisetum typhoides). La infraestructura destinada a la caballeriza presenta diversas irregularidades en cuanto a diseño, calidad de los materiales, tamaño de cuadras, espacio de bodega, comederos, bebederos y mal estado del piso, paredes y techo; asimismo hay deterioro generalizado en las divisiones de potreros destinados a los pastos; las áreas de esparcimiento y entrenamiento no presentan las condiciones óptimas para el entrenamiento y manejo general de los equinos. Se garantiza la alimentación a base de concentrados y los medicamentos apropiados a las enfermedades comunes que se presentan con más frecuencia (cólico visceral, piroplasmosis e infección renal). Los equinos pasan por un proceso para su preparación que incluye: adiestramiento, escuela, rutina de trabajo, higiene y manejo; los servicios que se generan son: cuido y manejo, alquiler para hípica y para servicio de monta. Las alternativas de mejora generadas del análisis FODA – DOFA consisten en ampliación y mejora general de infraestructura, mejoras en los procesos administrativos, elaboración de planes de marketing y sanitario