415 research outputs found

    Análisis de la retroalimentación de evidencias y la producción de textos escritos en estudiantes de secundaria de Huarochirí, 2021

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    El objetivo de la investigación fue analizar la retroalimentación y la producción de textos escritos en los estudiantes de secundaria desde la percepción de los actores educativos: especialistas de educación, directores, docentes y estudiantes; se recurrió al enfoque cualitativo, el paradigma hermenéutico interpretativo y el diseño fenomenológico. Se elaboró una guía de entrevista semiestructurada con cuatro preguntas sobre la retroalimentación y tres preguntas sobre producción de textos escritos durante la educación a distancia que fue aplicada de manera virtual. Los resultados revelaron que mayormente se ejecutan los tipos de retroalimentación elemental y descriptiva, usan los criterios de evaluación para aplicar las estrategias propuestas por Wilson y Anijovich de manera escrita en el WhatsApp y verbal a través de audios y llamadas telefónicas; y quienes la realizan son los docentes y las familias como fuente de retroalimentación surgida en el contexto pandémico. En la escritura de textos se comprobó el uso de las etapas de planificación donde predomina el propósito, el destinatario, el lenguaje y la estructura; en la textualización y revisión se priorizan las reglas ortográficas y superficialmente la cohesión y la coherencia. Aún no se promueve la reflexión, la regulación y la autonomía de los aprendizajes

    Modellazione e analisi di travi in parete sottile nell’ambito della Generalized Beam Theory

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    In this work, the Generalized Beam Theory (GBT) is used as the main tool to analyze the mechanics of thin-walled beams. After an introduction to the subject and a quick review of some of the most well-known approaches to describe the behaviour of thin-walled beams, a novel formulation of the GBT is presented. This formulation contains the classic shear-deformable GBT available in the literature and contributes an additional description of cross-section warping that is variable along the wall thickness besides along the wall midline. Shear deformation is introduced in such a way that the classical shear strain components of the Timoshenko beam theory are recovered exactly. According to the new kinematics proposed, a reviewed form of the cross-section analysis procedure is devised, based on a unique modal decomposition. Later, a procedure for a posteriori reconstruction of all the three-dimensional stress components in the finite element analysis of thin-walled beams using the GBT is presented. The reconstruction is simple and based on the use of three-dimensional equilibrium equations and of the RCP procedure. Finally, once the stress reconstruction procedure is presented, a study of several existing issues on the constitutive relations in the GBT is carried out. Specifically, a constitutive law based on mirroring the kinematic constraints of the GBT model into a specific stress field assumption is proposed. It is shown that this method is equally valid for isotropic and orthotropic beams and coincides with the conventional GBT approach available in the literature. Later on, an analogous procedure is presented for the case of laminated beams. Lastly, as a way to improve an inherently poor description of shear deformability in the GBT, the introduction of shear correction factors is proposed. Throughout this work, numerous examples are provided to determine the validity of all the proposed contributions to the field

    Seasonal and Spatial Patterns in Salinity, Nutrients, and Chlorophyll α in the Alvarado Lagoonal System, Veracruz, Mexico

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    Ten monthly collections, distributed among three seasons, were taken from July 2000 to June 2001 in the Alvarado lagoonal system, Veracruz, Mexico. Variables measured in situ included dissolved oxygen, salinity, and water temperature. Water samples were collected to determine concentrations of ammonium, nitrates, nitrites, orthophosphates, total phosphorus and chlorophyll α. Collections representing the rainy season were taken in September and October, those for the nortes season were taken in November, December, and January, and dry season collections were taken during February, March, May June, and July. There was seasonal and spatial variation in nutrient concentrations, and they were related to the discharge of the rivers; concentrations increased during the rainy and nortes seasons. Other factors affecting water quality included the constant discharge of organic materials into the system, resuspension of sediments during the nortes season and the biological activity within the system that assimilated the nutrients in the water. The Alvarado lagoonal system has three separate zones based on physicochemical characteristics; Camaronera Lagoon, Buen Pais Lagoon and the urban zone of Alvarado Lagoon, and the river zone in Alvarado Lagoon

    Approaching the genetic dissection of indirect adventitious organogenesis process in tomato explants

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    [EN] The screening of 862 T-DNA lines was carried out to approach the genetic dissection of indirect adventitious organogenesis in tomato. Several mutants defective in different phases of adventitious organogenesis, namely callus growth (tdc-1), bud differentiation (tdb-1,-2,-3) and shoot-bud development (tds-1) were identified and characterized. The alteration of the TDC-1 gene blocked callus proliferation depending on the composition of growth regulators in the culture medium. Calli from tds-1 explants differentiated buds but did not develop normal shoots. Histological analysis showed that their abnormal development is due to failure in the organization of normal adventitious shoot meristems. Interestingly, tdc-1 and tds-1 mutant plants were indistinguishable from WT ones, indicating that the respective altered genes play specific roles in cell proliferation from explant cut zones (TDC-1 gene) or in the organization of adventitious shoot meristems (TDS-1 gene). Unlike the previous, plants of the three mutants defective in the differentiation of adventitious shoot-buds (tdb-1,-2,-3) showed multiple changes in vegetative and reproductive traits. Cosegregation analyses revealed the existence of an association between the phenotype of the tdb-3 mutant and a T-DNA insert, which led to the discovery that the SlMAPKKK17 gene is involved in the shoot-bud differentiation process.Vicente Moreno and Rafael Lozano thank the Ministry of Science and Innovation (State Innovation Agency) for granting the projects PID2019-110833RB-C32 and PID2019-110833RB-C31. Benito Pineda's work in the context of this article has been funded by 'Aid for First Research Projects (PAID-06-18)' by the Vicerrectorado de Investigacion, Innovacion y Transferencia de la Universitat Politecnica de Valencia (UPV), Valencia, Spain'. The PhD fellowship for Jorge Sanchez-Lopez and Marybel Jaquez-Gutierrez were funded by the Universidad de Sinaloa and the CONACYT of Mexico.Sanchez-Lopez, J.; Atarés Huerta, A.; Jaquez-Gutierrez, M.; Ortiz-Atienza, A.; Capel, C.; Pineda Chaza, BJ.; García Sogo, B.... (2021). Approaching the genetic dissection of indirect adventitious organogenesis process in tomato explants. Plant Science. 302:1-14. https://doi.org/10.1016/j.plantsci.2020.110721S11430

    Chromosome 10Q2432 Variants associate With Brain arterial Diameters in Diverse Populations: a Genome-Wide association Study

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    BACKGROUND: Brain arterial diameters (BADs) are novel imaging biomarkers of cerebrovascular disease, cognitive decline, and dementia. Traditional vascular risk factors have been associated with BADs, but whether there may be genetic determinants of BADs is unknown. METHODS AND RESULTS: The authors studied 4150 participants from 6 geographically diverse population-based cohorts (40% European, 14% African, 22% Hispanic, 24% Asian ancestries). Brain arterial diameters for 13 segments were measured and averaged to obtain a global measure of BADs as well as the posterior and anterior circulations. A genome-wide association study revealed 14 variants at one locus associated with global BAD at genome-wide significance ( CONCLUSIONS: The current study reveals 3 novel risk loci

    Evaluation of evoh-coated pp films with oregano essential oil and citral to improve the shelf-life of packaged salad

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    [EN] The aim of this study was to improve the present packaging of salad by combining modified atmosphere packaging with a new antimicrobial active bag consisting of PP/EVOH film with oregano essential oil or citral, with the purpose of extending shelf-life and reducing possible microbiological risks. The (O-2) and CO2 barrier properties of PP/EVOH, mechanical properties (Young's modulus, tensile strength and elongation at break) were determined and compared with those of standard PP films. Antimicrobial tests were carried out for enterobacteria, total aerobic counts, yeasts and moulds, and lactic acid bacteria and psychrotrophic bacteria, and the effect of the release of the antimicrobial agent on the sensory characteristics of the salads was also studied. The application of the EVOH coating results in an increase in the tensile resistance of the PP films and a reduction in the elongation at break. The results showed that microorganism counts bacteria decreased especially at the beginning of the storage period. OEO and CITRAL samples had reductions of 1.38 log and 2.13 log respectively against enterobacterias, about 2 log against yeasts and moulds. The total aerobic counts reduced 1.08 log with OEO and 1.23 log with CITRAL and the reduction of lactic acid bacteria and psychrotrophic was about 2 log. Citral-based films appeared to be more effective than materials containing oregano essential oil in reducing spoilage flora during storage time. Sensory studies also showed that the package with citral was the most accepted by customers at the end of the shelf-life. (C) 2012 Elsevier Ltd. All rights reserved,Authors thank the financial support of the Spanish Ministry of Economy and Competitiveness (Project AGL2009-08776 and V.M-G fellowships), EU (Nafispack project 212544), Generalitat Valenciana (J.P.C. fellowship) and Mr. Karel Clapshaw (translation services).Muriel Galet, V.; Cerisuelo, JR.; López Carballo, G.; Aucejo, S.; Gavara Clemente, R.; Hernández Muñoz, P. (2013). Evaluation of evoh-coated pp films with oregano essential oil and citral to improve the shelf-life of packaged salad. Food Control. 30(1):137-143. https://doi.org/10.1016/j.foodcont.2012.06.032S13714330

    Planeación, gobernanza y sustentabilidad Retos y desafíos desde el enfoque territorial

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    Frente a la compleja realidad actual, resulta ineludible el desarrollo de la investigación científica de los fenómenos y procesos urbanos, territoriales y ambientales, que contribuya a su comprensión y la construcción de alternativas de solución a los retos y desafíos vigentes. En este contexto, el abordaje de las ciudades y regiones metropolitanas, el ordenamiento del territorio y la ocupación del espacio, así como la relación sociedad-naturaleza y la complejidad ambiental, precisa la generación de metodologías y procesos de investigación multi e inter disciplinarios que contribuyan a la comprensión de los procesos socioterritoriales, el mejoramiento de las condiciones de vida y la conservación ambiental.Programa de Fortalecimiento de la Calidad Educativa PFCE-2016 proyecto K0313101
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