Electronic Design of a DC-DC Boost Converter for Powering a Lo-Ra Communication Board with Bioelectricity by “Plantas Andinas”

The use of bioelectricity in various areas of science has made it indispensable to resort to new technologies to take full advantage of this natural resource. Plants are living beings, and through their biochemical processes produce a small amount of electricity derived from oxidation-reduction processes. For this reason, it is proposed to use electronic and power techniques to increase the flow of electrons produced by plants of Andean characteristics, and consequently feed a Lo-Ra type communication card, meeting the needs of long-distance data transmission, used in the collection of field information, either in areas where access or availability of power lines is complex. This proposal motivates us to continue working on sustainable energy and the exploitation of natural resources. This document details the theory, practice, and methods used to meet the objective of supplying power to a wireless communication system over a long distance. First, a description of the most important issues to be addressed is developed, and then special focus is given to the design for development of the power electronics circuit, specifically an elevator type DC-DC converter. Finally, the results obtained through the implementation used in this case are documented. Keywords: bioelectricity, MFC, boost-converter, Andean plants, totora, Lo-Ra TTGO. Resumen El uso de bioelectricidad en diversas áreas de la ciencia ha hecho indispensable recurrir a nuevas tecnologías para aprovechar al máximo este recurso natural. Las plantas, como seres vivos, producen una pequeña cantidad de electricidad a través de sus procesos bioquímicos, derivada de procesos de oxidación-reducción. Por esta razón, se propone utilizar técnicas electrónicas y de potencia para aumentar el flujo de electrones producidos por plantas de características andinas, y alimentar así una tarjeta de comunicación de tipo Lo-Ra, satisfaciendo las necesidades de transmisión de datos a larga distancia, utilizadas en la recolección de información de campo, ya sea en áreas donde el acceso o la disponibilidad de líneas eléctricas es compleja Esta propuesta motiva a continuar trabajando en energía sostenible y en la explotación de recursos naturales. Este documento detalla la teoría, práctica y los métodos utilizados para cumplir con el objetivo de suministrar energía a un sistema de comunicación inalámbrico a larga distancia. En primer lugar, se desarrolla una descripción de los temas más importantes a abordar, y luego se presta especial atención al desarrollo del diseño del circuito de electrónica de potencia, específicamente un convertidor DC-DC tipo elevador; y finalmente, se documentan los resultados obtenidos a través de la implementación utilizada en este caso. Palabras Clave: bioelectricidad, CCM, convertidor-elevador, plantas andinas, totora, TTGO Lo-Ra

Moving loads on railway bridges: The Spanish Code approach

This paper presents the results of part of the research carried out by a committee in charge of the elaboration of the new Spanish Code of Actions in Railway Bridges. Following the work developed by the European Rail Research Institute (ERRI), the dynamic effects caused by the Spanish high-speed train TALGO have been studied and compared with other European trains. A simplified envelope of the impact coefficient is also presented. Finally, the train-bridge interactions has been analysed and the results compared with those obtained from simple models based on moving loads

Comparing the performance of two structural indicators for different water models while seeking for connections between structure and dynamics in the glassy regime

In this work, we compare the performance of two structural indicators based on the degree of translational order up to the second coordination shell in three water models: SPC/E, TIP4P/2005, and TIP5P. Beyond directly contrasting their distributions for different temperatures to evidence their usefulness in estimating the fraction of structured and unstructured molecules and, when possible, their classification capability, we also correlate them with an indirect measure of structural constraint: the dynamic propensity. Furthermore, this procedure enables us to show the existence of evident correlations between structural and dynamical information. More specifically, we find that locally structured molecules display a preference for low dynamic propensity values and, more conspicuously, that locally unstructured molecules are extremely subject to high dynamic propensity. This result is particularly relevant for the supercooled regime where the establishment of firm links between the structure and dynamics has remained rather elusive since the occurrence of dynamics that vary in orders of magnitude upon supercooling usually contrast with barely noticeable overall structural changes.Fil: Verde, Alejandro Raúl. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Montes de Oca, Joan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Accordino, Sebastián R.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Alarcón, Laureano M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Appignanesi, Gustavo Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentin

The effects of intrinsic noise on the behaviour of bistable cell regulatory systems under quasi-steady state conditions

We analyse the effect of intrinsic fluctuations on the properties of bistable stochastic systems with time scale separation operating under1 quasi-steady state conditions. We first formulate a stochastic generalisation of the quasi-steady state approximation based on the semi-classical approximation of the partial differential equation for the generating function associated with the Chemical Master Equation. Such approximation proceeds by optimising an action functional whose associated set of Euler-Lagrange (Hamilton) equations provide the most likely fluctuation path. We show that, under appropriate conditions granting time scale separation, the Hamiltonian can be re-scaled so that the set of Hamilton equations splits up into slow and fast variables, whereby the quasi-steady state approximation can be applied. We analyse two particular examples of systems whose mean-field limit has been shown to exhibit bi-stability: an enzyme-catalysed system of two mutually-inhibitory proteins and a gene regulatory circuit with self-activation. Our theory establishes that the number of molecules of the conserved species are order parameters whose variation regulates bistable behaviour in the associated systems beyond the predictions of the mean-field theory. This prediction is fully confirmed by direct numerical simulations using the stochastic simulation algorithm. This result allows us to propose strategies whereby, by varying the number of molecules of the three conserved chemical species, cell properties associated to bistable behaviour (phenotype, cell-cycle status, etc.) can be controlled.Comment: 33 pages, 9 figures, accepted for publication in the Journal of Chemical Physic

Entorno laboral y social en las maquiladoras de Coahuila: estudio muestral

Abstract. The purpose of this study is to analyze the labor and social environment that prevails in the maquiladoras (assemble plants) located in the northern border states of México, particularly in the state of Coahuila; also it is addressed the importance of factors contributing to improve labor conditions and productivity. The study is based in a sample of 20 firms located in the counties of Saltillo, Ramos Arizpe, Monclova, Torreón, Sabinas, Piedras Negras and Ciudad Acuña. This study analizes the main socialeconomic figures of theworkers, their labor conditions in regard to labor security, training, rights and duties, social security and social environment in which they live in. Conclusions and recommendations are related to improving training and labor conditions, as well as fostering a new labor culture, health, social security and social environment.Key words: Health, labor conditions, social environment , social security, workersResumen. El presente estudio tiene como propósito analizar las condiciones que presenta el entorno laboral y social en el cual se desempeñan los trabajadores de las maquiladoras que operan en la frontera de México con Estados Unidos, particularmente en el estado de Coahuila, y evaluar los factores que podrían contribuir al mejoramiento de dichas condiciones y de la productividad laboral. Al respecto, se realizó un estudio muestral que consideró a 20 empresas ubicadas en los municipios de Saltillo, Ramos Arizpe, Monclova, Torreón, Sabinas, Piedras Negras y Ciudad Acuña. El estudio analiza las principales características socioeconómicas de los trabajadores , sus condiciones laborales relativas a seguridad en el trabajo, capacitación, derechos y obligaciones, seguridad social y entorno en el que viven. Las conclusiones y recomendaciones se relacionan con los ámbitos de la educación, el mejoramiento de las condiciones de trabajo, el fomento de una nueva cultura laboral, el apoyo a la salud y la seguridad social y el mejoramiento de las condiciones del entornosocial.Palabras clave: Condiciones laborales, entorno social, salud, seguridad social, trabajadore

Genetic Mapping in Tetraploid Alfalfa: Results and Prospects

Among the difficulties of improving forages is their perennial nature, which necessarily requires long selection cycles to fully evaluate genotypes. Further, traits of particular importance—yield and winter hardiness—are difficult to assess on single plants, necessitating evaluation of progeny, which is both time consuming and expensive. Because of this, yield of many forages, and particularly alfalfa, has not improved substantially over the past 25 years (Riday and Brummer, 2002). Winter hardiness often has a negative correlation with autumn growth, although some evidence suggests this is not always true (Brummer et al., 2000). One way to overcome some of these limitations may be through the use of genetic markers to help select desirable genotypes. The objective of this experiment was to test the hypothesis that quantitative trait loci (QTL) for complex agronomic traits could be identified in a segregating tetraploid alfalfa population

Contribution of picoplankton to the total particulate organic carbon concentration in the eastern South Pacific

International audienceProchlorococcus, Synechococcus, picophytoeukaryotes and bacterioplankton abundances and contributions to the total particulate organic carbon concentration, derived from the total particle beam attenuation coefficient (cp), were determined across the eastern South Pacific between the Marquesas Islands and the coast of Chile. All flow cytometrically derived abundances decreased towards the hyper-oligotrophic centre of the gyre and were highest at the coast, except for Prochlorococcus, which was not detected under eutrophic conditions. Temperature and nutrient availability appeared important in modulating picophytoplankton abundance, according to the prevailing trophic conditions. Although the non-vegetal particles tended to dominate the cp signal everywhere along the transect (50 to 83%), this dominance seemed to weaken from oligo- to eutrophic conditions, the contributions by vegetal and non-vegetal particles being about equal under mature upwelling conditions. Spatial variability in the vegetal compartment was more important than the non-vegetal one in shaping the water column particle beam attenuation coefficient. Spatial variability in picophytoplankton biomass could be traced by changes in both total chlorophyll a (i.e. mono + divinyl chlorophyll a) concentration and cp. Finally, picophytoeukaryotes contributed ~38% on average to the total integrated phytoplankton carbon biomass or vegetal attenuation signal along the transect, as determined by size measurements (i.e. equivalent spherical diameter) on cells sorted by flow cytometry and optical theory. Although there are some uncertainties associated with these estimates, the new approach used in this work further supports the idea that picophytoeukaryotes play a dominant role in carbon cycling in the upper open ocean, even under hyper-oligotrophic conditions

T cell receptor engagement by peptide–MHC ligands induces a conformational change in the CD3 complex of thymocytes

The T cell receptor (TCR) can recognize a variety of cognate peptide/major histocompatibility complex (pMHC) ligands and translate their affinity into distinct cellular responses. To achieve this, the nonsignaling αβ heterodimer communicates ligand recognition to the CD3 signaling subunits by an unknown mechanism. In thymocytes, we found that both positive- and negative-selecting pMHC ligands expose a cryptic epitope in the CD3 complex upon TCR engagement. This conformational change is induced in vivo and requires the expression of cognate MHC. We conclude that TCR engagement with a cognate pMHC ligand induces a conformational change in the CD3 complex of thymocytes and propose that this marks an initial event during thymic selection that signals the recognition of self-antigen