451 research outputs found

    Deterministic and time resolved thermo-magnetic switching in a nickel nanowire

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    [EN]Heating a ferromagnetic material is often perceived as detrimental for most applications. This is indeed the case for modern nano-scaled spintronic devices which are operated solely (at least ideally) by an electric current. Heat is a by-product of the current-driven operation and it deteriorates many functionalities of the device. A large scientific and technological effort is devoted these days to avoid heat in modern magnetic nano devices. Here we show that heat can be used to provide an additional and useful degree of freedom in the control of the local magnetization at the nanoscale. In a ferromagnetic nanowire, temperature is used to induce a magnetic switching through a perfectly deterministic mechanism. The nucleation of the magnetic domain walls that triggers the switching can be achieved at a field considerably smaller than the nucleation field and, importantly, the exact moment of the magnetic switching can be pre-determined with nanosecond precision by controlling the power delivered locally to the switching area. With the help of micromagnetic simulations and a theoretical model, we provide an accurate explanation of how this deterministic thermo-magnetic switching operates. The concepts described in this work may lead to an increased functionality in magnetic nano-devices based on magnetic domain walls.MAT2017-87072-C4-1-P,MAT2017-87072-C4-4-P and MAT2017-87072-C4-3-P from the Spanish government SA299P18 from the Junta de Castilla y Leon POCI-01-0145-FEDER-028676 from Portuguese FCT COMPETE 2020 (FEDER)

    Development and tests of a new prototype detector for the XAFS beamline at Elettra Synchrotron in Trieste

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    The XAFS beamline at Elettra Synchrotron in Trieste combines X-ray absorption spectroscopy and X-ray diffraction to provide chemically specific structural information of materials. It operates in the energy range 2.4-27 keV by using a silicon double reflection Bragg monochromator. The fluorescence measurement is performed in place of the absorption spectroscopy when the sample transparency is too low for transmission measurements or the element to study is too diluted in the sample. We report on the development and on the preliminary tests of a new prototype detector based on Silicon Drift Detectors technology and the SIRIO ultra low noise front-end ASIC. The new system will be able to reduce drastically the time needed to perform fluorescence measurements, while keeping a short dead time and maintaining an adequate energy resolution to perform spectroscopy. The custom-made silicon sensor and the electronics are designed specifically for the beamline requirements.Comment: Proceeding of the 6YRM 12th-14th Oct 2015 - L'Aquila (Italy). Accepted for publication on Journal of Physics: Conference Serie

    Análise da diversidade da vegetação de uma floresta a ser manejada na Amazônia Ocidental.

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    As florestas de terra firme na Amazônia são as que ocupam a maior parte das áreas florestadas e vêm sofrendo impacto com a exploração madeireira predatória. É crescente a necessidade de sistemas de exploração florestal que sejam sustentáveis ecológica e economicamente. O manejo florestal de impacto reduzido surge como alternativa, pois nesse sistema é possível diminuir consideravelmente os desperdícios e danos à floresta. Para o acompanhamento da resposta da floresta em regime de manejo é essencial o uso de parcelas permanentes, sendo estas instaladas antes da exploração e remedidas periodicamente. O objetivo do presente estudo foi apresentar a diversidade da vegetação de uma floresta de terra firme observada a partir da instalação de parcelas permanentes

    Generation, establishment and characterization of a pluripotent stem cell line (CVTTHi001-A) from primary fibroblasts isolated from a patient with activated PI3 kinase delta syndrome (APDS2)

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    APDS2 is caused by mutations in PIK3R1 gene resulting in constitutive PI3Kδ activation. PI3Kδ is predominantly expressed in leukocytes and plays critical roles in regulating immune responses. Here we first derived fibroblast primary cells from a skin biopsy of a patient carrying a heterozygous single T deletion in intron 11 of the PIK3R1 gene. We next present the derivation of an induced pluripotent stem cell (iPS) line using a non-integrative reprogramming technology. Pluripotent-related hallmarks are further shown, including: iPSCs self-renewal and expression of pluripotent and differentiation markers after in vitro differentiation towards embryonic germ layers, assessed by RT-PCR and immunofluorescence

    What did Hughes teach us about repairing surgical defects in the lower eyelid?

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    La reconstrucción del párpado inferior sigue siendo un reto, especialmente la reparación de defectos que abarcan más de la mitad de su superficie horizontal. El colgajo de Hughes del párpado superior ipsilateral es la técnica quirúrgica de elección para los tumores de gran tamaño del párpado inferior. Presentamos el caso de una paciente con carcinoma basocelular superficial de párpado inferior izquierdo que fue intervenida con extirpación del tumor con margen de seguridad y reparación del defecto primario mediante este colgajo. Describimos la técnica de Hughes paso a paso, sus potenciales complicaciones, así como los puntos clave en su ejecución para conseguir unos resultados satisfactorios.Lower eyelid reconstrution remains a challenge, especially the repair of defects that cover more than a half of its horizontal surface. The Hughes flap of the ipsilateral upper eyelid is the surgical technique of choice for large tumors of the lower eyelid. We present the case of a patient with superficial basal cell carcinoma of the lower left eyelid who underwent surgery with excision of the tumor with margin of safety and repair of the primary defect using this flap. We describe the Hughes technique step by step, its potential complications, as well as the key points in its execution to achieve satisfactory results
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