302 research outputs found

    Memory effect in triglycine sulfate induced by a transverse electric field: specific heat measurement

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    The influence of a transverse electric field in the specific heat of triglycine sulphate (TGS) has been studied. The specific heat of TGS has been measured heating the sample from ferroelectric to paraelectric phase after prolonged transverse electric field (i.e. perpendicular to the ferroelectric axis). It is shown that the specific heat of TGS can remember the temperature TsT_s at which the transverse field was previously applied.Comment: ReVTeX4 Twocolumn 4 pages, 4 figure

    Covadonga Sevilla Cueva: In memoriam

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    Foreword

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    Stem cells as a therapeutic tool for the blind: biology and future prospects

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    Retinal degeneration due to genetic, diabetic and age-related disease is the most common cause of blindness in the developed world. Blindness occurs through the loss of the light-sensing photoreceptors; to restore vision, it would be necessary to introduce alternative photosensitive components into the eye. The recent development of an electronic prosthesis placed beneath the severely diseased retina has shown that subretinal stimulation may restore some visual function in blind patients. This proves that residual retinal circuits can be reawakened after photoreceptor loss and defines a goal for stem-cell-based therapy to replace photoreceptors. Advances in reprogramming adult cells have shown how it may be possible to generate autologous stem cells for transplantation without the need for an embryo donor. The recent success in culturing a whole optic cup in vitro has shown how large numbers of photoreceptors might be generated from embryonic stem cells. Taken together, these threads of discovery provide the basis for optimism for the development of a stem-cell-based strategy for the treatment of retinal blindness

    Influence of the electric field on the latent heat of the ferroelectric phase transition in KDP

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    The specific heat, heat flux (DTA trace) and dielectric constant of KDP ferroelectric crystal have been measured simultaneously for various electric fields with a conduction calorimeter. The specific heat presents a strong anomaly but these simultaneous measurements allow us to evaluate the latent heat accurately. Latent heat decreases with field and the value of critical electric field --that where latent heat disappears-- is estimated to be (0.44\pm0.03) kV/cm. Incidentally, we have measured simultaneously the dielectric permittivity which suggests that latent heat is developed as domains are growing.Comment: 7 pages, 6 figures, ReVTeX, twocolumn format, to appear in J. Phys. Cond. Matte

    A change in SHATTERPROOF protein lies at the origin of a fruit morphological novelty and a new strategy for seed dispersal in Medicago genus

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    [EN] Angiosperms are the most diverse and numerous group of plants, and it is generally accepted that this evolutionary success owes in part to the diversity found in fruits, key for protecting the developing seeds and ensuring seed dispersal. Although studies on the molecular basis of morphological innovations are few, they all illustrate the central role played by transcription factors acting as developmental regulators. Here, we show that a small change in the protein sequence of a MADS-box transcription factor correlates with the origin of a highly modified fruit morphology and the change in seed dispersal strategies that occurred in Medicago, a genus belonging to the large legume family. This protein sequence modification alters the functional properties of the protein, affecting the affinities for other protein partners involved in high-order complexes. Our work illustrates that variation in coding regions can generate evolutionary novelties not based on gene duplication/subfunctionalization but by interactions in complex networks, contributing also to the current debate on the relative importance of changes in regulatory or coding regions of master regulators in generating morphological novelties.This work was supported by the Spanish Ministerio de Ciencia e Innovacion (grant no. BIO2009-09920 to C.Fe.), the European Union (grant no. FP7-PEOPLE-PIRSES-2009-247589 to C.Fe. and A.C.d.O.), and a Fellowship for Foreign Young Postdocs from the Spanish Ministerio de Ciencia e Innovacion (to C.Fo.).Fourquin, C.; Del Cerro Fernández, C.; Victoria, FC.; Vialette-Guiraud, A.; De Oliveira, AC.; Ferrandiz Maestre, C. (2013). A change in SHATTERPROOF protein lies at the origin of a fruit morphological novelty and a new strategy for seed dispersal in Medicago genus. Plant Physiology. 162(2):907-917. https://doi.org/10.1104/pp.113.217570S907917162

    Robotización del cultivo en hileras para la agricultura ecológica. Proyecto SUREVEG

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    La demanda de productos de agricultura ecológica está en auge, experimentando un continuo crecimiento. Este aumento de la demanda precisa de un crecimiento de la producción, que debe llevarse acabo sin renunciar al bajo impacto ambiental asociado a este tipo de agricultura. En este proyecto se trabaja en una herramiental robótica para automatizar la fertilización orgánica de cultivos en franjas

    Corrección del Artefacto de Truncamiento en TAC mediante Aprendizaje profundo

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    Actas de: CASEIB 2020: XXXVIII Congreso Anual de la Sociedad Española de Ingeniería Biomédica, 25–27 Nov, 2020 (congreso virtual).La adquisición de proyecciones incompletas debido a que parte de la muestra se extiende fuera del campo de visión, resulta en inconsistencias en los datos que dan lugar a lo que se conoce como artefacto de truncamiento. Se han propuesto varios métodos para la compensación de la falta de datos, basados en la extrapolación de las proyecciones, pero ninguno consigue recuperar completamente los datos truncados. Este trabajo presenta un nuevo método de compensación del artefacto de truncamiento en imágenes de TAC basado en técnicas de aprendizaje profundo. La evaluación en datos simulados a partir de estudios de roedores muestra la viabilidad de la propuesta.Este trabajo ha sido financiado por el Ministerio de Ciencia, Innovación y Universidades (Instituto de Salud Carlos III, proyecto DTS17/00122; Agencia Estatal de Investigación, proyecto DPI2016-79075-R-AEI/FEDER, UE), cofinanciado por Fondos de la Unión Europea (FEDER), "A way of making Europe". Además, ha sido financiado por el Programa de apoyo a la realización de proyectos interdisciplinares de I+D para jóvenes investigadores de la Universidad Carlos III de Madrid 2019-2020 en el marco del Convenio Plurianual Comunidad de Madrid- Universidad Carlos III de Madrid (proyecto DEEPCT-CM-UC3M). El CNIC está financiado por el Ministerio de Ciencia, Innovación y Universidades y la fundación PRO-CNIC y es un centro de excelencia Severo Ochoa (SEV-2015-0505)
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