1,340 research outputs found

    Expansión en ortodoncia

    Get PDF

    El acero inoxidable en Ortodoncia

    Get PDF

    Optical fibers to measure temperature vertical profile at sea

    Get PDF
    The paper is focus in the use the optical fiber to measure the temperature in various heigh at the same time to get a temperature vertical variation. The temperature measurements are puntual while the Bragg gratings located in the fiber.Peer Reviewe

    Application of the Wavelet Transform to the Digital Image Processing of Electron Micrographs and of Backreflection Electron Diffraction Patterns

    Get PDF
    In this work we explore the use of the so-called wavelet transform in the digital image processing of micrographs. The wavelet transform of an image f(x,y) is defined as: Wf(s,u,v) = f(x,y) s Ψ(s(x-u),s(y-v)) dxdy where Ψ is an analyzing function called wavelet and which is in our examples always taken to be the Mexican hat given by Ψ(x)=(2-(x2+y2))exp(-(x2+y2)/2) Some synthetic images are shown in which it can be clearly seen how the wavelet transform can be useful to reveal edges and to emphasize the boundaries of the clusters. The technique is applied in the case of the CoMoS catalysts, in which the wavelet transform can be used to emphasize the hexagonal domains while filtering the noise quite effectively. The technique is next applied to electron backreflection patterns where substantial noise reduction and emphasis of the lines are achieved. Several examples of the application of this processing tool to high resolution images of metallic particles and to quasicrystals are presented

    The neurobiological foundations of learning disabilities

    Full text link
    Learning disabilities constitute a heterogeneous group of disorders that involve significant alterations in different cognitive domains (acquisition and use of language, reasoning, mathematical skills, visuospatial abilities, and so forth) that are not accounted for by a low level of intelligence, inadequate sociocultural development or lack of academic opportunities. They result from an alteration in basic psychological processes, developmentally linked to an alteration in the central nervous system. Current functional neuroimaging techniques have made it possible to develop a new type of approach to the neurofunctional foundations underlying these disorders, especially with regard to difficulties in the realm of reading/writing (developmental dyslexia) and attention deficit hyperactivity disorder (ADHD), which have their highest incidence among the infantile population of school-age children. Development. Neuroimaging studies have revealed a pattern of atypical activity in both kinds of disorders. In the case of dyslexia, alterations have been observed in the perisylvian circuits that underlie the mechanisms involved in reading skills. Studies into ADHD suggest a fronto-striatal dysfunction linked to the difficulties encountered to achieve inhibitory control, as well as alterations in the inferior parietal and posterior temporal cortex. Conclusions. Functional neuroimaging studies have shown that the clinical manifestations of these disorders are not only due to a dysfunction in specific areas of the brain, but also to alterations in the pattern of connectivityLas dificultades de aprendizaje comprenden un grupo heterogéneo de trastornos que implican alteraciones significativas en diferentes dominios cognitivos (adquisición y uso del lenguaje, razonamiento, habilidades matemáticas, visuoespaciales, etc.) no justificadas por bajo nivel intelectual, desarrollo sociocultural inadecuado o falta de oportunidades académicas. Éstas son el resultado de una alteración en los procesos psicológicos básicos, evolutivamente ligados a una alteración del sistema nervioso central. Las actuales técnicas de neuroimagen funcional han permitido un nuevo tipo de acercamiento a las bases neurofuncionales de estos trastornos, particularmente de las dificultades en el ámbito de la lectoescritura (dislexia evolutiva) y del trastorno por déficit de atención e hiperactividad (TDAH), los cuales tienen el mayor nivel de incidencia en la población escolar infantil. Desarrollo. Los estudios de neuroimagen han revelado un patrón de actividad atípico en ambos tipos de trastorno. En el caso de la dislexia, se han observado alteraciones de los circuitos perisilvianos que sustentan los mecanismos de lectura. Los estudios sobre TDAH sugieren una disfunción frontoestriatal ligada a las dificultades para el control inhibitorio, así como alteraciones en la corteza temporal posterior y parietal inferior. Conclusiones. Los estudios de neuroimagen funcional revelan que las manifestaciones clínicas de estos trastornos no se deben sólo a la disfunción de áreas cerebrales concretas, sino también a alteraciones en el patrón de conectividadAs dificuldades de aprendizagem compreendem um grupo heterogéneo de perturbações que implicam alterações significativas em diferentes domínios cognitivos (aquisição e uso da linguagem, raciocínio, habilidades matemáticas, visuo-espaciais, etc.) não justificadas por baixo nível intelectual, desenvolvimento sócio-cultural inadequado ou falta de oportunidades académicas. Estas são o resultado de uma alteração nos processos psicológicos básicos, evolutivamente ligados a uma alteração do sistema nervoso central. As técnicas actuais de neuroimagem funcional permitiram um novo tipo de abordagem às bases neuro-funcionais destas perturbações, particularmente das dificuldades no âmbito da leitura e da escrita (dislexia evolutiva) e da perturbação por défice de atenção e hiperactividade (PDAH), as quais têm o maior nível de incidência na população escolar infantil. Desenvolvimento. Os estudos das neuroimagens revelaram um padrão de actividade atípico em ambos os tipos de perturbação. No caso da dislexia, foram observadas alterações dos circuitos perisilvícos que sustentam os mecanismos de leitura. Os estudos sobre o PDAH sugerem uma disfunção fronto-estriatal ligada às dificuldades no controlo inibitório, assim como alterações no córtex temporal posterior e parietal inferior. Conclusões. Os estudos de neuroimagem funcional revelam que as manifestações clínicas destas perturbações não se devem apenas à disfunção de áreas cerebrais concretas, como também a alterações no padrão de conectividad

    Comparative analysis of the compressive strength of concrete under different curing methods

    Get PDF
    Concrete is the most widely used material in construction, which possesses different characteristics and possible manufacturing methods. Concrete is, also, characterized by its high resistance to compression and durability, factors that could have been directly influenced by the curing method in early ages. The objective of this research is to demonstrate the importance of the concrete curing process, as well as to analyze the influence of the chosen curing method on the compression resistance. 48 concrete test samples were manufactured, by the standard requirements. Subsequently, the samples were divided into eight batches, subjected to different types of curing: immersion curing, twice a day; outdoor curing; total immersion curing in different waters, application of commercial curing agent; with polyethylene foil coating and without curing. Performing compression testing at 7 and 28 days. Among the results obtained, the batch that underwent the method of curing with polyethylene coating presented a more efficient effect in terms of resistance to compression; followed by the techniques of immersion in water

    5G Spectrum: enabling the future mobile landscape

    Full text link
    © 2015 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The arrival of the fifth generation (5G) is expected to come together with three important enablers. First, the densification of access nodes will continue. Second, 5G networks must be highly flexible and adapt to the dynamism of the traffic location and patterns. For this, some of the radio access network (RAN) functionalities will run in large computer centers, able to dynamically assign more or fewer units of computation to the virtual cells distributed in the network. Finally, a complex landscape of spectrum availability and access will emerge where multiple frequency bands, subject to different regulations including various forms of shared spectrum, are expected to be available to wireless communication systems.Schotten, HD.; Uusitalo, MA.; Monserrat Del Río, JF.; Queseth, O. (2015). 5G Spectrum: enabling the future mobile landscape. IEEE Communications Magazine. 53(7):16-17. doi:10.1109/MCOM.2015.7158260S161753

    Capillaria plica como agente etiológico de hematuria en un perro

    Get PDF
    Se describen los hallazgos clínicos y hematológicos, diagnóstico y tratamiento de un caso de hematuria y disuria provocado por Capíllaria plica en un perro macho de un año y medio.Clinical picture, haematologic features, diagnostic techniques and treatment protocols are discussed regarding a male dog one year and a half old with hematuria caused by Capillaria plica
    corecore