9,194 research outputs found

    Spin-transfer torque on a single magnetic adatom

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    We theoretically show how the spin orientation of a single magnetic adatom can be controlled by spin polarized electrons in a scanning tunneling microscope configuration. The underlying physical mechanism is spin assisted inelastic tunneling. By changing the direction of the applied current, the orientation of the magnetic adatom can be completely reversed on a time scale that ranges from a few nanoseconds to microseconds, depending on bias and temperature. The changes in the adatom magnetization direction are, in turn, reflected in the tunneling conductance.Comment: 5 pages, 3 figure

    The emergence of classical behavior in magnetic adatoms

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    A wide class of nanomagnets shows striking quantum behavior, known as quantum spin tunneling (QST): instead of two degenerate ground states with opposite magnetizations, a bonding-antibonding pair forms, resulting in a splitting of the ground state doublet with wave functions linear combination of two classically opposite magnetic states, leading to the quenching of their magnetic moment. Here we study how QST is destroyed and classical behavior emerges in the case of magnetic adatoms, as the strength of their coupling, either to the substrate or to each other, is increased. Both spin-substrate and spin-spin coupling renormalize the QST splitting to zero allowing the environmental decoherence to eliminate superpositions between classical states, leading to the emergence of spontaneous magnetization.Comment: 5 pages, 4 figure

    Aparato uni-persona para topografía de playas

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    Near real time seismic data from the coastal ocean

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    A moored-buoy system for collecting near real-time seismic data from the coastal ocean has been developed and will be deployed for its initial field trial in the fall of 2016. The technology that makes possible the near real time telemetry of seismic data is the inductive modem technology. This type of data telemetry provides a solution that is convenient, economical, reliable, and flexible. We present results of a prototype system that demonstrate the feasibility of this concept. It will transmit continuous data at a rate of about 1000 bps to a radio link in the surface buoy. A GPS receiver on the surface buoy will be configured to perform accurate and synchronized timestamps on the seismic data on the sea surface, which will make it possible to include data from these undersea systems in the existing seismic data network. Power to operate the system will be supplied by solar panels and rechargeable batteries on the surface buoy and batteries on OBS.Peer ReviewedPostprint (published version

    Melanoma expression analysis with Big Data technologies

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    Melanoma is a highly immunogenic tumor. Therefore, in recent years physicians have incorporated drugs that alter the immune system into their therapeutic arsenal against this disease, revolutionizing in the treatment of patients in an advanced stage of the disease. This has led us to explore and deepen our knowledge of the immunology surrounding melanoma, in order to optimize its approach. At present, immunotherapy for metastatic melanoma is based on stimulating an individual’s own immune system through the use of specific monoclonal antibodies. The use of immunotherapy has meant that many of patients with melanoma have survived and therefore it constitutes a present and future treatment in this field. At the same time, drugs have been developed targeting specific mutations, specifically BRAF, resulting in large responses in tumor regression (set up in this clinical study to 18 months), as well as a higher percentage of long-term survivors. The analysis of the gene expression changes and their correlation with clinical changes can be developed using the tools provided by those companies which currently provide gene expression platforms. The gene expression platform used in this clinical study is NanoString, which provides nCounter. However, nCounter has some limitations as the type of analysis is restricted to a predefined set, and the introduction of clinical features is a complex task. This paper presents an approach to collect the clinical information using a structured database and a Web user interface to introduce this information, including the results of the gene expression measurements, to go a step further than the nCounter tool. As part of this work, we present an initial analysis of changes in the gene expression of a set of patients before and after targeted therapy. This analysis has been carried out using Big Data technologies (Apache Spark) with the final goal being to scale up to large numbers of patients, even though this initial study has a limited number of enrolled patients (12 in the first analysis). This is not a Big Data problem, but the underlaying study aims at targeting 20 patients per year just in Málaga, and this could be extended to be used to analyze the 3.600 patients diagnosed with melanoma per year.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. This work was funded in part by Grants TIN2014-58304-R (Ministerio de Ciencia e Innovación) and P11-TIC-7529 and P12-TIC-1519 (Plan Andaluz de Investigación, Desarrollo e Innovación). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

    La filosofía del aprendizaje cooperativo aplicada a entornos libres

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    La presente ponencia es fruto de un Proyecto de Innovación Educativa (PIE13-164) llevado a cabo en la Universidad de Málaga, que se inició en 2013 y que finaliza este año. El proyecto tiene como objetivo involucrar a profesores y estudiantes en dinámicas de aprendizaje cooperativo a través de la construcción de su propio material de clase. Para ello todos los participantes del proyecto, alumnos, académicos y otros profesionales comprometidos con la filosofía del procomún, han empleado herramientas de software libre para traducir al castellano una recopilación de distintos escritos desarrollados por el profesor Langdon Winner, uno de los filósofos de la tecnología más reconocido a nivel internacional.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
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