363 research outputs found

    Magnetostatic interactions between magnetic nanotubes

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    The investigation of interactions between magnetic nanotubes is complex and often involves substantial simplifications. In this letter an analytical expression for the magnetostatic interaction, taking into account the geometry of the tubes, has been obtained. This expression allows for the definition of a critical vertical separation for relative magnetization between nanotubes and can be used for tailoring barcode-type nanostructures with prospective applications such as biological separation and transport.Comment: 4 pages, 5 figure

    Angular dependence of magnetic properties in Ni nanowire arrays

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    The angular dependence of the remanence and coercivity of Ni nanowire arrays produced inside the pores of anodic alumina membranes has been studied. By comparing our analytical calculations with our measurements, we conclude that the magnetization reversal in this array is driven by means of the nucleation and propagation of a transverse wall. A simple model based on an adapted Stoner-Wohlfarth model is used to explain the angular dependence of the coercivity

    Persistence of the Z = 28 shell gap in A = 75 isobars: Identification of a possible (1/2-) μs isomer in Co75 and β decay to Ni75

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    Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAMBackground: The evolution of shell structure around doubly magic exotic nuclei is of great interest in nuclear physics and astrophysics. In the 'southwest' region of Ni78, the development of deformation might trigger a major shift in our understanding of explosive nucleosynthesis. To this end, new spectroscopic information on key close-lying nuclei is very valuable. Purpose: We intend to measure the isomeric and β decay of Co75, with one-proton and two-neutron holes relative to Ni78, to access new nuclear structure information in Co75 and its β-decay daughters Ni75 and Ni74. Methods: The nucleus Co75 is produced in relativistic in-flight fission reactions of U238 at the Radioactive Ion Beam Factory in the RIKEN Nishina Center. Its isomeric and β decay are studied exploiting the BigRIPS and EURICA setups. Results: We obtain partial β-decay spectra for Ni75 and Ni74, and report a new isomeric transition in Co75. The energy [Eγ = 1914(2)keV] and half-life [t1/2 = 13(6)μs] of the delayed γ ray lend support for the existence of a Jπ = (1/2-) isomeric state at 1914(2) keV. A comparison with PFSDG-U shell-model calculations provides a good account for the observed states in Ni75, but the first calculated 1/2- level in Co75, a prolate K = 1/2 state, is predicted about 1 MeV below the observed (1/2-) level. Conclusions: The spherical-like structure of the lowest-lying excited states in Ni75 is proved. In the case of Co75, the results suggest that the dominance of the spherical configurations over the deformed ones might be stronger than expected below Ni78. Further experimental efforts to discern the nature of the Jπ = (1/2-) isomer are necessar

    Aproximación enfermera a los cuidados no profesionales a través de las vivencias de una cuidadora

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    Introducción: El envejecimiento progresivo de la población española, y la creciente disminución de los recursos institucionales para el cuidado de las personas dependientes, implica que cada día sea mayor la necesidad de disponer de cuidadoras no profesionales. En la mayoría de los casos la calidad de vida de las personas dependientes depende de los cuidados no profesionales prestados por mujeres y familiares en general de la persona dependiente. Cuidados y cuidadores son a menudo invisibilizados y/o poco reconocidos desde el punto de vista social, institucional y legislativo. Es función de enfermería conocer esta problemática, identificar a las cuidadoras no profesionales y las necesidades derivadas de su rol, y dispensarles la ayuda, conocimiento y apoyo necesario para realizar esta tarea en las mejores condiciones posibles. Objetivos: Definir los conceptos relacionados con "el cuidar" dentro del sector popular de la salud para poder comprender las vivencias y la problemática de las personas que ejercen de cuidadoras dentro de este sector. Analizar e interpretar el discurso de una cuidadora informal relacionándolo con las categorías diagnósticas propuestas por la NANDA para poder descubrir los problemas relacionados con el cuidado donde sería posible la intervención enfermera al cuidador. Material y métodos: Revisión bibliográfica sistemática con inclusión de textos legislativos relevantes para este trabajo. Entrevista semiestructurada a una cuidadora no profesional. Análisis del discurso. Codificación abierta e inductiva de la información con establecimiento de dominios y categorías de análisis, tomando como modelo la “Teoría Fundamentada” de Glaser y Strauss. Resultados: dominios y categorías diagnósticas NANDA en base al discurso de una cuidadora. Conclusiones: Dada la importancia los cuidados no profesionales es fundamental que los programas de atención sanitaria de nuestra cultura y nuestra sociedad, creen las bases para garantizar el bienestar biopsicosocial de la cuidadora no profesional. Por otra parte, las cuidadoras no profesionales sufren numerosos problemas de salud en los que el profesional de enfermería puede actuar, especialmente detectando y previniendo los factores de riesgo para el cuidador

    Magnetostatic bias in multilayer microwires: theory and experiments

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    The hysteresis curves of multilayer microwires consisting of a soft magnetic nucleus, intermediate non-magnetic layers, and an external hard magnetic layer are investigated. The magnetostatic interaction between magnetic layers is proved to give rise to an antiferromagnetic-like coupling resulting in a magnetostatic bias in the hysteresis curves of the soft nucleus. This magnetostatic biasing effect is investigated in terms of the microwire geometry. The experimental results are interpreted considering an analytical model taking into account the magnetostatic interaction between the magnetic layers.Comment: 6 pages, 7 figure

    Beyond Diagnosis: Evolving Prostate Biopsy in the Era of Focal Therapy

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    Despite decades of use as the “gold standard” in the detection of prostate cancer, the optimal biopsy regimen is still not universally agreed upon. While important aspects such as the need for laterally placed biopsies and the importance of apical cancer are known, repeated studies have shown significant patients with cancer on subsequent biopsy when the original biopsy was negative and an ongoing suspicion of cancer remained. Attempts to maximise the effectiveness of repeat biopsies have given rise to the alternate approaches of saturation biopsy and the transperineal approach. Recent interest in focal treatment of prostate cancer has further highlighted the need for accurate detection of prostate cancer, and in response, the introduction of transperineal template-guided biopsy. While the saturation biopsy approach and the transperineal template approach increase the detection rate of cancer in men with a previous negative biopsy and appear to have acceptable morbidity, there is a lack of clinical trials evaluating the different biopsy strategies. This paper reviews the evolution of prostatic biopsy and current controversies

    Surviving anoxia in marine sediments: The metabolic response of ubiquitous benthic foraminifera (Ammonia tepida)

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    High input of organic carbon and/or slowly renewing bottom waters frequently create periods with low dissolved oxygen concentrations on continental shelves and in coastal areas; such events can have strong impacts on benthic ecosystems. Among the meiofauna living in these environments, benthic foraminifera are often the most tolerant to low oxygen levels. Indeed, some species are able to survive complete anoxia for weeks to months. One known mechanism for this, observed in several species, is denitrification. For other species, a state of highly reduced metabolism, essentially a state of dormancy, has been proposed but never demonstrated. Here, we combined a 4 weeks feeding experiment, using 13C-enriched diatom biofilm, with correlated TEM and NanoSIMS imaging, plus bulk analysis of concentration and stable carbon isotopic composition of total organic matter and individual fatty acids, to study metabolic differences in the intertidal species Ammonia tepida exposed to oxic and anoxic conditions. Strongly contrasting cellular-level dynamics of ingestion and transfer of the ingested biofilm components were observed between the two conditions. Under oxic conditions, within a few days, intact diatoms were ingested, degraded, and their components assimilated, in part for biosynthesis of different cellular components: 13C-labeled lipid droplets formed after a few days and were subsequently lost (partially) through respiration. In contrast, in anoxia, fewer diatoms were initially ingested and these were not assimilated or metabolized further, but remained visible within the foraminiferal cytoplasm even after 4 weeks. Under oxic conditions, compound specific 13C analyses showed substantial de novo synthesis by the foraminifera of specific polyunsaturated fatty acids (PUFAs), such as 20:4(n-6). Very limited PUFA synthesis was observed under anoxia. Together, our results show that anoxia induced a greatly reduced rate of heterotrophic metabolism in Ammonia tepida on a time scale of less than 24 hours, these observations are consistent with a state of dormancy
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