1,525 research outputs found
LA FUNDAMENTACIÓN TEÓRICA DEL PROBLEMA CIENTÍFICO EN LAS INVESTIGACIONES PEDAGÓGICAS
A problem has been determined as a situation that favors the appearance and worsening of social difficulties, including those with a pedagogical nature, or that limits or obstructs the normal development of processes. The problem is presented as a contradiction formed by two closely-related elements. However, the problem in the investigations is not always justified enough in order to clarify its scientific intention. It is not invented, but it is formulated departing from the contradictions of the reality itself. The social investigations and particularly the pedagogical ones, due to the nature of its object of investigation and the categorical system that compliments them, they are not beyond that problem situation. The considerations that are presented below fulfill the purpose of motivating towards the reflection on the topic.Se entiende por problema una situación que favorece la aparición y la agudización de dificultades sociales entre ellas las de carácter pedagógico, o que limita o entorpece el desarrollo normal de los procesos. El problema se presenta como una contradicción formada por dos elementos internamente relacionados. Sin embargo el problema no siempre en las investigaciones se fundamenta lo suficiente, como para que quede clara su intencionalidad científica. El problema no se inventa, se formula a partir de las contradicciones de la propia realidad. Las investigaciones sociales y en particular las pedagógicas, dada la naturaleza de su objeto de investigación y el sistema categorial que la conforman, no escapan a tal problemática. Las consideraciones que presentamos a continuación cumplen con el propósito de motivar a la reflexión sobre el tema
Recent evidences of Domvs in Ilipa (Alcalá del Río, Seville): Old mosaics in new urban context
En el presente trabajo se presentan los resultados preliminares de una intervención arqueológica preventiva llevada a cabo muy recientemente
en el área urbana de Alcalá del Río, antigua Ilipa. La excavación, a pesar de ser limitada en extensión, ha permitido contextualizar los
ambientes domésticos propios de un mosaico conocido
ya de antiguo. De esta forma, lo que era un dato aislado cobra así sentido, sumándose al actual y creciente conocimiento de la ciudad romana,
proporcionando nuevos y valiosos datos sobre aspectos urbanísticos, tecnológicos, constructivos o socioeconómicos, entre otros.Preliminary results of a preventive archaeological intervention carried out recently in the urban area of Alcalá del Rio, former Ilipa, are presented in this paper. The excavation, despite being of limited surface, has allowed
characterizing the domestic contexts related to a mosaic that was already known more than two decades ago. In this way an isolate item starts to
be meaningful and the new information increases the current and growing knowledge of the Roman city, providing valuable new data on urban, technological, constructive or socioeconomic aspects,
among others
SISTEMA DE CAPTACIÓN DE DATOS DEL FUNCIONAMIENTO DE MOTORES PARA LA TOMA DE DECISIONES EN EMPRESAS DE PRODUCCIÓN
El presente trabajo tiene como objetivo proponer un sistema para la captación, procesado y almacenamiento de datos en la monitorización del estado de funcionamiento de motores eléctricos, para la toma de decisiones en el departamento de manufactura en empresas de producción. Se realiza un análisis de lo existente y se sintetiza verificando la mejor opción para monitorear el funcionamiento de motores. Utilizando placas electrónicas con sensores, microcontrolador, comunicación Bluetooth y almacenamiento de datos en una aplicación móvil. Se ha proporcionado a la aplicación la posibilidad de realizar estadística con los datos para anticiparse a fallos que produzcan paros en la producción. El sistema desarrollado (Sistema de Adquisición de Datos de motores, o sus siglas SADAM) en este trabajo tiene la ventaja frente a los sistemas comerciales existentes de ser fácilmente instalado sin parar la producción, no necesitar de ningún sistema previo y ser reconfigurable. Los subsistemas desarrollados, se pueden modificar para adaptarse a la monitorización del estado de otros equipos que necesiten medir distintas variables mediante sensores
HACIA UN CURRÍCULO FLEXIBLE: SALIDAS INTERMEDIAS Y CURSOS OPTATIVOS
Traditionally, the curricula of the university degree courses have been focused on the formation of professionals within the required period for their graduation (5-6 years), with a single exit to the labour market. This research is aimed at contributing, from the Labour and Professional Formation of the students, to the definition of their formative process, according to their needs and interests. This paper also analyses the advantages of the intermediate exits in a university degree course, and how they allow students to obtain a college degree without affecting the continuation of the higher education studies or the quality of the formation of the university graduate. Such reality favours the insertion of the students in the labour market under conditions that suit the qualifications and experience related to the degree they are doing. From the curricular perspective, the proposal is based on flexible curricula with intermediate exits, where optional and/or elective courses can be of great importance.Tradicionalmente los currículos de las carreras universitarias se han caracterizado por el predominio de una formación de tipo terminal con una sola salida al mercado laboral. Con el fin de contribuir de manera flexible desde la Formación Laboral y Profesional a que los estudiantes definan su trayectoria formativa, en este trabajo se analizan las ventajas de las salidas intermedias en una carrera universitaria, sin afectar la continuidad de los estudios superiores ni la calidad en la formación del egresado universitario. Estas permiten a los estudiantes obtener un título de nivel medio que los pone en condiciones de salir al mercado laboral con un perfil ocupacional relacionado con la carrera universitaria que estudia. Desde la perspectiva curricular la propuesta realizada se basa en currículos flexibles con salidas intermedias donde pueden ser de gran utilidad los cursos optativos y/o electivos
LA EDUCACIÓN NO FORMAL SUSTENTADA EN LOS PRINCIPIOS DE LA PEDAGOGÍA SOCIAL Y SU APLICACIÓN EN EL CONTEXTO ANGOLANO: LA EDUCACIÓN NO FORMAL EN EL CONTEXTO ANGOLANO
Late in the decade of the sixties of the twentieth century, it was of general concern that the traditional education systems did not provide a solution to the major economic and social problems that many countries were facing. There was a commonidea that those traditional systems could not adapt to the rapid socio-economic changes that were taking place. As a solution to the problem, non-formal education appears in the field of pedagogy. When education is aimed at contributing to face the dissimilar problems present in the community, ranging from health situations to the multiple implications of science and technology in everyday life, it is necessary to combine, in the educational process, non-formal education with Social Pedagogy. The evaluation of this educational process is the objective of this article.Desde finales de los años sesenta del siglo XX, se empezó a hablar de que los sistemas tradicionales de educación no daban solución a todos los grandes problemas económicos y sociales que se presentaban en muchos países. Existía la impresión de que los referidos sistemas no lograban adaptarse a los rápidos cambios socioeconómicos que se estaban produciendo. Como solución al problema aparece en la palestra pedagógica la educación no formal. Cuando está educación se dirige a contribuir a enfrentar los disimiles problemas presentes en la comunidad, que van desde las situaciones sanitarias a las múltiples implicaciones de la ciencia y la técnica en la vida cotidiana, es necesario combinar, en el proceso formativo, la educación no formal con la Pedagogía Social. La valoración este proceso educativo es el objetivo del presente artículo
Cortistain is expressed in a distinct subset of cortical interneurons
Cortistatin is a presumptive neuropeptide that shares 11 of its 14 amino acids with somatostatin. In contrast to somatostatin, administration of cortistatin into the rat brain ventricles specifically enhances slow wave sleep, apparently by antagonizing the effects of acetylcholine on cortical excitability. Here we show that preprocortistatin mRNA is expressed in a subset of GABAergic cells in the cortex and hippocampus that partially overlap with those containing somatostatin. A significant percentage of cortistatin-positive neurons is also positive for parvalbumin. In contrast, no colocalization was found between cortistatin and calretinin, cholecystokinin, or vasoactive intestinal peptide. During development there is a transient increase in cortistatin-expressing cells in the second postnatal week in all cortical areas and in the dentate gyrus. A transient expression of preprocortistatin mRNA in the hilar region at P16 is paralleled by electrophysiological changes in dentate granule cells. Together, these observations suggest mechanisms by which cortistatin may regulate cortical activity
Effects of differential diffusion on nonpremixed-flame temperature
This numerical and analytical study investigates effects of differential diffusion on nonpremixed-flame temperatures. To focus more directly on transport effects the work considers a single irreversible reaction with an infinitely fast rate, with Schab-Zel'dovich coupling functions introduced to write the conservation equations of energy and reactants in a chemistry-free form accounting for non-unity values of the fuel Lewis number L-F. Different flow configurations of increasing complexity are analyzed, beginning with canonical flamelet models that are reducible to ordinary differential equations, for which the variation of the flame temperature with fuel-feed dilution and L-F is quantified, revealing larger departures from adiabatic values in dilute configurations with oxidizer-to-fuel stoichiometric ratios S of order unity. Marble's problem of an unsteady flame wrapped by a line vortex is considered next, with specific attention given to large-Peclet-number solutions. Unexpected effects of differential diffusion are encountered for S < 1 near the vortex core, including superadiabatic/subadibatic flame temperatures occurring for values of L-F larger/smaller than unity as well as temperature profiles peaking on the oxidizer side of the flame. Direct numerical simulations of diffusion flames in a temporal turbulent mixing layer are used to further investigate these unexpected differential- diffusion effects. The results, confirming and extending previous findings, underscore the nontrivial role of differential diffusion in nonpremixed-combustion systems
Low Vitamin D Levels and Frailty Status in Older Adults: A Systematic Review and Meta-Analysis
Serum vitamin D deficiency is widespread among older adults and is a potential modifiable risk factor for frailty. Moreover, frailty has been suggested as an intermediate step in the association between low levels of vitamin D and mortality. Hence, we conducted a systematic review of the literature and meta-analysis to test the possible association of low concentrations of serum 25-hydroxyvitamin D (25(OH)D), a marker of vitamin D status, with frailty in later life. We reviewed cross-sectional or longitudinal studies evaluating populations of older adults and identifying frailty by a currently validated scale. Meta-analyses were restricted to cross-sectional data from studies using Fried’s phenotype to identify frailty. Twenty-six studies were considered in the qualitative synthesis, and thirteen studies were included in the meta-analyses. Quantitative analyses showed significant differences in the comparisons of frail (standardized mean difference (SMD)—1.31, 95% confidence interval (CI) (−2.47, −0.15), p = 0.0271) and pre-frail (SMD—0.79, 95% CI (−1.58, −0.003), p = 0.0491) subjects vs. non-frail subjects. Sensitivity analyses reduced heterogeneity, resulting in a smaller but still highly significant between-groups difference. Results obtained indicate that lower 25(OH)D levels are significantly associated with increasing frailty severity. Future challenges include interventional studies testing the possible benefits of vitamin D supplementation in older adults to prevent/palliate frailty and its associated outcomes.This research was funded by Xunta de Galicia [ED431B 2019/02]; Ministerio de Educación, Cultura y
Deporte [BEAGAL18/00142 to V.V, PRX19/00353 to B.L.]; and Deputación Provincial de A Coruña [to D.M.-P. and
M.S.-F.]info:eu-repo/semantics/publishedVersio
Paper‑based broadband fexible photodetectors with van der Waals materials
Layered metal chalcogenide materials are exceptionally appealing in optoelectronic devices thanks to their extraordinary optical properties. Recently, their application as flexible and wearable photodetectors have received a lot of attention. Herein, broadband and high-performance paper-based PDs were established in a very facile and inexpensive method by rubbing molybdenum disulfide and titanium trisulfide crystals on papers. Transferred layers were characterized by SEM, EDX mapping, and Raman analyses, and their optoelectronic properties were evaluated in a wavelength range of 405–810 nm. Although the highest and lowest photoresponsivities were respectively measured for TiS3 (1.50 mA/W) and MoS2 (1.13 μA/W) PDs, the TiS3–MoS2 heterostructure not only had a significant photoresponsivity but also showed the highest on/off ratio (1.82) and fast response time (0.96 s) compared with two other PDs. This advantage is due to the band offset formation at the heterojunction, which efficiently separates the photogenerated electron–hole pairs within the heterostructure. Numerical simulation of the introduced PDs also confirmed the superiority of TiS3–MoS2 heterostructure over the other two PDs and exhibited a good agreement with the experimental results. Finally, MoS2 PD demonstrated very high flexibility under applied strain, but TiS3 based PDs suffered from its fragility and experience a remarkable drain current reduction at strain larger than ± 0.33%. However, at lower strains, all PDs displayed acceptable performance
On the structure and properties of silver nanoparticles
Silver tetrahedral nanoparticles (NP) were synthesized using the inert gas condensation technique. We performed morphological and optical characterization of the nanoparticles (NPs) using atomic force microscopy (AFM), mass spectroscopy (MS), and UV-visible spectroscopy. The Ag NPs were produced by modified magnetron sputtering, followed by thermalization and condensation in a high pressure zone. Along the synthesis process, the size of the NPs was controlled through the handling of the gas flow (Ar and He), the magnetron power, and the length of the aggregation zone. We optimized the synthesis parameters to obtain a peak on the size distribution of Ag NPs around of 5 nm (as measured with AFM and MS). The AFM measurements show that the particles have tetrahedral shape, with a fair correspondence with a 2925-atoms ideal tetrahedron. We performed a set of Molecular Dynamics (MD) calculations using the Embedded Atom potential model to simulate the dynamics of particles with different shapes, obtaining that, at sizes close to that of the particles produced experimentally, the tetrahedra may be as energetically stable as cuboctahedra of roughly the same size, and that their melting point is below but close to that of the bulk. We also found that both the size and shape of the nanoparticles determine the shift of the UV-visible absorption spectrum. Finally, we observed the formation of atomic islands above the faces of the Ag tetrahedral NPs, in agreement with the results obtained from the MD simulations
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