185 research outputs found

    Notas técnicas. Recomendaciones para la fabricación y empleo de bloques de huecos de hormigón

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    Aplicación del ciclo de Deming para mejorar la productividad en el área de producción de la empresa Máquinas y Equipos de Acero s.a. Breña – Lima 2017

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    El presente trabajo de investigación es de tipo cuantitativo, de diseño pre experimental, cuyo objetivo general fue determinar la manera de como la implementación del ciclo de Deming mejoró la productividad a través de la implementación de un control adecuado con los 4 pasos de Deming: Planificar, hacer, verificar y actuar en el área operaciones de la empresa máquinas y equipos de acero S.A en el 2017. En el presente proyecto de investigación se demostró que mediante el uso de herramientas y técnicas de mejora continua del ciclo de Deming que es posible corregir los problemas acaecidos en dicha área enfocándonos en los procesos de control y supervisión los cuales no existían en la empresa de una forma estándar, produciendo ineficiencias e ineficacias que impactaban grandemente en la productividad a través de una demora en los procesos de fabricación y reproceso. Asimismo, se pudo observar y demostrar que todo ello era originario de una mala planificación, organización y supervisión adecuada en el área de operaciones. El estudio principalmente se basó en determinar de qué manera el ciclo de Deming influyó en la mejora de la productividad en el área de operaciones, haciendo que el taller tenga los controles necesarios para la fabricación de diversos productos industriales encomendados por los clientes, logrando cumplir con las fechas de entrega pactadas con los clientes. De esta manera, con los resultados analizados con el estadígrafo de Shapiro Wilk se puede demostrar con datos estadísticos que la implementación del ciclo de Deming, si logró mejorar la productividad, logrando mejorar a su vez la eficiencia y eficacia el área operaciones de la empresa máquinas y equipos de acero S.A en el 2017

    A Sinorhizobium meliloti-specific N-acyl homoserine lactone quorum-sensing signal increases nodule numbers in Medicago truncatula independent of autoregulation

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    N-acyl homoserine lactones (AHLs) act as quorum sensing signals that regulate cell-density dependent behaviors in many gram-negative bacteria, in particular those important for plant-microbe interactions. AHLs can also be recognized by plants, and this may influence their interactions with bacteria. Here we tested whether the exposure to AHLs affects the nodule-forming symbiosis between legume hosts and rhizobia. We treated roots of the model legume, Medicago truncatula, with a range of AHLs either from its specific symbiont, Sinorhizobium meliloti, or from the potential pathogens, Pseudomonas aeruginosa and Agrobacterium vitis. We found increased numbers of nodules formed on root systems treated with the S. meliloti-specific AHL, 3-oxo-C14-homoserine lactone, at a concentration of 1 μM, while the other AHLs did not result in significant changes to nodule numbers. We did not find any evidence for altered nodule invasion by the rhizobia. Quantification of flavonoids that could act as nod gene inducers in S. meliloti did not show any correlation with increased nodule numbers. The effects of AHLs were specific for an increase in nodule numbers, but not lateral root numbers or root length. Increased nodule numbers following 3-oxo-C14-homoserine lactone treatment were under control of autoregulation of nodulation and were still observed in the autoregulation mutant, sunn4 (super numeric nodules4). However, increases in nodule numbers by 3-oxo-C14-homoserine lactone were not found in the ethylene-insensitive sickle mutant. A comparison between M. truncatula with M. sativa (alfalfa) and Trifolium repens (white clover) showed that the observed effects of AHLs on nodule numbers were specific to M. truncatula, despite M. sativa nodulating with the same symbiont. We conclude that plant perception of the S. meliloti-specific 3-oxo-C14-homoserine lactone influences nodule numbers in M. truncatula via an ethylene-dependent, but autoregulation-independent mechanism.Debora F. Veliz-Vallejos was supported by a PhD scholarship from Becas Chile; Ulrike Mathesius was supported by a Future Fellowship (FT100100669) from the Australian Research Council

    A Sinorhizobium meliloti-specific N-acyl homoserine lactone quorum-sensing signal increases nodule numbers in Medicago truncatula independent of autoregulation

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    N-acyl homoserine lactones (AHLs) act as quorum sensing signals that regulate cell-density dependent behaviors in many gram-negative bacteria, in particular those important for plant-microbe interactions. AHLs can also be recognized by plants, and this may influence their interactions with bacteria. Here we tested whether the exposure to AHLs affects the nodule-forming symbiosis between legume hosts and rhizobia. We treated roots of the model legume, Medicago truncatula, with a range of AHLs either from its specific symbiont, Sinorhizobium meliloti, or from the potential pathogens, Pseudomonas aeruginosa and Agrobacterium vitis. We found increased numbers of nodules formed on root systems treated with the S. meliloti-specific AHL, 3-oxo-C14-homoserine lactone, at a concentration of 1 μM, while the other AHLs did not result in significant changes to nodule numbers. We did not find any evidence for altered nodule invasion by the rhizobia. Quantification of flavonoids that could act as nod gene inducers in S. meliloti did not show any correlation with increased nodule numbers. The effects of AHLs were specific for an increase in nodule numbers, but not lateral root numbers or root length. Increased nodule numbers following 3-oxo-C14-homoserine lactone treatment were under control of autoregulation of nodulation and were still observed in the autoregulation mutant, sunn4 (super numeric nodules4). However, increases in nodule numbers by 3-oxo-C14-homoserine lactone were not found in the ethylene-insensitive sickle mutant. A comparison between M. truncatula with M. sativa (alfalfa) and Trifolium repens (white clover) showed that the observed effects of AHLs on nodule numbers were specific to M. truncatula, despite M. sativa nodulating with the same symbiont. We conclude that plant perception of the S. meliloti-specific 3-oxo-C14-homoserine lactone influences nodule numbers in M. truncatula via an ethylene-dependent, but autoregulation-independent mechanism

    Comparison Between the Material Improvement of the Megarok and San José Quarries, Applying the AASTHO Standards

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    Comparative analyzes were carried out between the materials of the Magarok and San José quarries, taking into account AASTHO standards with the objective of being used as a base / sub-base in the pavement structure. The asphalt emulsion material was stabilized to increase the strength and give the material sub-base and / or base characteristics, with a suitable mixing design, obtaining results with suitable characteristics to be used in the pavement structure composed of a 65 % Asphalt AC 20; 34.30% water and 0.70% ASFIER 121 emulsions, with good resistance to the stability of the materials

    A Mathematical Framework for Agent Based Models of Complex Biological Networks

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    Agent-based modeling and simulation is a useful method to study biological phenomena in a wide range of fields, from molecular biology to ecology. Since there is currently no agreed-upon standard way to specify such models it is not always easy to use published models. Also, since model descriptions are not usually given in mathematical terms, it is difficult to bring mathematical analysis tools to bear, so that models are typically studied through simulation. In order to address this issue, Grimm et al. proposed a protocol for model specification, the so-called ODD protocol, which provides a standard way to describe models. This paper proposes an addition to the ODD protocol which allows the description of an agent-based model as a dynamical system, which provides access to computational and theoretical tools for its analysis. The mathematical framework is that of algebraic models, that is, time-discrete dynamical systems with algebraic structure. It is shown by way of several examples how this mathematical specification can help with model analysis.Comment: To appear in Bulletin of Mathematical Biolog

    Ballast Treated with Asphalt Emulsion, Megarok and San Jose. AASTHO Standards

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    In the research work, the results obtained at the laboratory level of the lending material (ballast) treated with asphalt emulsion from the quarries "Megarok and San José" are compared, applying the AASTHO standards. The quarries are located in the Picoazá-La Sequita parish of the Portoviejo canton. Samples from both quarries were evaluated in the laboratory and it was possible to carry out tests of natural humidity, Atterberg, granulometric, compaction, and soil bearing capacity (CBR). Based on the results obtained, they were compared by disclosing which of the quarries meets the appropriate conditions within the construction standards and techniques, in order to stabilize the material with asphalt emulsion; in addition to comparing it with the specifications of the AASTHO standards and the MTOP standard. The result was that the materials extracted from the quarries do not meet the technical specifications; but when mixed with the asphalt emulsion, the Megarok material fulfills as type A base

    Conception rate of artificially inseminated holstein cows affected by cloudy vaginal mucus, under intense heat conditions.

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    The objective of this work was to obtain prevalence estimates of cloudy vaginal mucus in artificially inseminated Holstein cows raised under intense heat, in order to assess the effect of meteorological conditions on its occurrence during estrus and to determine its effect on conception rate. In a first study, an association was established between the occurrence of cloudy vaginal mucus during estrus and the conception rate of inseminated cows (18,620 services), raised under intense heat (mean annual temperature of 22°C), at highly technified farms, in the arid region of northern Mexico. In a second study, data from these large dairy operations were used to assess the effect of meteorological conditions throughout the year on the occurrence of cloudy vaginal mucus during artificial insemination (76,899 estruses). The overall rate of estruses with cloudy vaginal mucus was 21.4% (16,470/76,899; 95% confidence interval = 21.1?21.7%). The conception rate of cows with clean vaginal mucus was higher than that of cows with abnormal mucus (30.6 vs. 22%). Prevalence of estruses with cloudy vaginal mucus was strongly dependent on high ambient temperature and markedly higher in May and June. Acceptable conception rates in high milk-yielding Holstein cows can only be obtained with cows showing clear and translucid mucus at artificial insemination.Título em português: Taxa de concepção de vacas Holandesas inseminadas artificialmente e afetadas por muco vaginal turvo, sob condições de intenso calor

    Manifestations faded gradually replacement of alfalfa ("Medicado sativa L.") by barley ("Hordeum vulgare L.") sprount in portions of Guinea pigs ("Cavia porcellus L.") in the stage of growth

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    El experimento fue conducido en el Centro de Producción de Cuyes de la Universidad Nacional de Huancavelica con el objetivo de evaluar la utilización de cuatro niveles (0, 25, 50 y 75%) de cebada hidropónica (CH) en substitución de la alfalfa en la alimentación de cuyes machos y hembras de la Línea Perú, en la fase de crecimiento, en número de 72, con 18 días de edad y 175 g de PV inicial medio confinados durante 42 días. Las raciones experimentales isoproteícas, fueron ofrecidos a los animales a voluntad y divididos en dos porciones (8 y 17 h). Fue utilizado el diseño experimental completamente aleatorizado y los tratamientos distribuidos en esquema factorial 2x4 (sexo x niveles de cebada hidropónica) con tres repeticiones por tratamiento, constituido cada unidad experimental por tres cuyes. Existió reducción lineal para machos en el consumo de MS en g/día y g/kg0.75 con el aumento de los niveles de substitución, este comportamiento también fue verificado para el consumo de PC (g/día). Hubo efecto cúbico para el consumo de PC por los cuyes hembras, en g/día, en g/kg0.75 y en %PV. La substitución de la alfalfa por la CH afectó la conversión alimenticia, cuyo comportamiento fue cuadrático y cúbico para machos y hembras, respectivamente. La CH influyó de forma cúbica sobre el peso final y ganancia de peso diario en los cuyes machos y hembras. Se concluye que es posible substituir la alfalfa por la CH hasta el nivel de 75% en cuyes hembras. El nivel de 25% de substitución proporciona las mejores ganancias de peso y pesos finales en cuyes machos y hembras en crecimiento, lo que pone de manifiesto el efecto positivo de la inclusión de la CH en la ración de cuyes en crecimiento.The experiment was conducted at the Center for Guinea Pig Production, National University of Huancavelica in order to evaluate the use of four levels (0, 25, 50 and 75%) of hydroponic barley (CH) in substitution of alfalfa in the feeding male and female guinea pigs of Peru line, in the growth phase, in number of 72, with 18 days of age and 175 g of initial PV means confined for 42 days. Isoproteic the experimental diets were offered ad libitum to the animals and divided in to two portions (8 and 17 h). It was used the completely randomized design and treatments distributed in factorial scheme 2x4 (sex x levels hydroponic barley) with three replicates per treatment, each experimental unit consists of three guinea pigs. Linear reduction existed for males MS consumption in g / g / day kg 0.75 with increasing substitution levels, this behavior was also verified for PC consumption (g / day). There was a cubic effect for consumption by the female guinea pigs PC in g / day, in g / kg0.75 and in % PV. The substitution of CH alfalfa affected by feed conversion, whose behavior was quadratic and cubic for males and females, respectively. The CH influenced cubical on final weight and daily weight gain in male and female guinea pigs. We conclude that it is possible to replace the CH alfalfa to the level of 75% in female guinea pigs. The level of 25% substitution provides the best weight gain and final weights in males and females growing guinea pigs, which shows the positive effect of the inclusion of CH in the ration of growing guinea pigs

    Non-homogenous disks in the chain of matrices

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    We investigate the generating functions of multi-colored discrete disks with non-homogenous boundary conditions in the context of the Hermitian multi-matrix model where the matrices are coupled in an open chain. We show that the study of the spectral curve of the matrix model allows one to solve a set of loop equations to get a recursive formula computing mixed trace correlation functions to leading order in the large matrix limit.Comment: 25 pages, 4 figure
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