1,353 research outputs found

    Photoluminescence Imaging and LBIC Characterization of Defects in mc-Si Solar Cells

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    Today's photovoltaic market is dominated by multicrystalline silicon (mc-Si) based solar cells with around 70% of worldwide production. In order to improve the quality of the Si material, a proper characterization of the electrical activity in mc-Si solar cells is essential. A full-wafer characterization technique such as photoluminescence imaging (PLi) provides a fast inspection of the wafer defects, though at the expense of the spatial resolution. On the other hand, a study of the defects at a microscopic scale can be achieved through the light-beam induced current technique. The combination of these macroscopic and microscopic resolution techniques allows a detailed study of the electrical activity of defects in mc-Si solar cells. In this work, upgraded metallurgical-grade Si solar cells are studied using these two techniques

    Optical/NIR stellar absorption and emission-line indices from luminous infrared galaxies

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    We analyze a set of optical-to-near-infrared long-slit nuclear spectra of 16 infrared-luminous spiral galaxies. All of the studied sources present H2_2 emission, which reflects the star-forming nature of our sample, and they clearly display H I emission lines in the optical. Their continua contain many strong stellar absorption lines, with the most common features due to Ca I, Ca II, Fe I, Na I, Mg I, in addition to prominent absorption bands of TiO, VO, ZrO, CN and CO. We report a homogeneous set of equivalent width (EW) measurements for 45 indices, from optical to NIR species for the 16 star-forming galaxies as well as for 19 early type galaxies where we collected the data from the literature. This selected set of emission and absorption-feature measurements can be used to test predictions of the forthcoming generations of stellar population models. We find correlations among the different absorption features and propose here correlations between optical and NIR indices, as well as among different NIR indices, and compare them with model predictions. While for the optical absorption features the models consistently agree with the observations,the NIR indices are much harder to interpret. For early-type spirals the measurements agree roughly with the models, while for star-forming objects they fail to predict the strengths of these indices.Comment: accepted for publication in MNRA

    Extension of the SIESTA MHD equilibrium code to free-plasma-boundary problems

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    is a recently developed MHD equilibrium code designed to perform fast and accurate calculations of ideal MHD equilibria for three-dimensional magnetic configurations. Since SIESTA does not assume closed magnetic surfaces, the solution can exhibit magnetic islands and stochastic regions. In its original implementation SIESTA addressed only fixed-boundary problems. That is, the shape of the plasma edge, assumed to be a magnetic surface, was kept fixed as the solution iteratively converges to equilibrium. This condition somewhat restricts the possible applications of SIESTA. In this paper, we discuss an extension that will enable SIESTA to address free-plasma-boundary problems, opening up the possibility of investigating problems in which the plasma boundary is perturbed either externally or internally. As an illustration, SIESTA is applied to a configuration of the W7-X stellarator.This research was funded in part by the Ministerio de Economía, Industria y Competitividad of Spain, Grant No. ENE2015-68265. This research was carried out in part at the Max-Planck-Institute for Plasma Physics in Greifswald (Germany), whose hospitality is gratefully acknowledged. This research was supported in part by the U.S. Department of Energy, Office of Fusion Energy Sciences under Award DE-AC05-00OR22725. SIESTA runs have been carred out in Uranus, a supercomputer cluster located at Universidad Carlos III de Madrid and funded jointly by the European Regional Development Funds (EU-FEDER) Project No. UNC313-4E-2361, and by the Ministerio de Economía, Industria y Competitividad via the National Project Nos. ENE2009-12213-C03-03, ENE2012-33219, and ENE2012-31753

    Evolución del desarrollo del color en sistema modelo de composición similar al dulce de leche. Influencia del tiempo de calentamiento y del Ph = Color development in dulce de leche-like system. Effect of heating time and pH

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    El color es un atributo importante en la elección del producto dulce de leche por parte del consumidor. El mismo se desarrolla en el proceso de elaboración debido principalmente a las reacciones de pardeamiento no enzimático, las cuales se ven influenciadas por varios factores. En este trabajo se evaluó el desarrollo de color, con el tiempo de tratamiento térmico y el pH inicial como variables tecnológicas, en un sistema modelo compuesto de caseinato, lactosa, sacarosa y agua destilada cuya composición fue similar a la del dulce de leche comercial. El estudio del color se realizó utilizando los parámetros de medición de color del sistema CIELAB y el índice de Kubelka Munk (K/S). Con ambos métodos se constató un aumento significativo del dE*ab y del K/S con el tiempo de tratamiento térmico y el pH inicial. Con el sistema CIELAB además se observó una tendencia a disminuir la luminosidad con el tiempo y el aumento del pH inicial, y el aumento de a* con el tiempo

    An Unusual Metastatic Renal Cell Carcinoma with Maintained Complete Response to Sunitinib Treatment

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    Recently, metastatic renal cell carcinoma (mRCC) treatment has changed dramatically with the onset of new therapies against molecular targets replacing immunotherapy as standard treatment. We report the case of a 49-year-old patient with a moderately differentiated renal clear cell carcinoma without extracapsular extension who underwent radical nephrectomy. Eight months after surgery, he developed a thyroid metastasis which was also treated surgically with a hemithyroidectomy. Seventy-five months after nephrectomy, the patient presented an upper gastrointestinal bleeding due to a duodenal metastasis that infiltrates the head of the pancreas. The treatment applied was surgery by duodenopancreatectomy, with positive surgical margins in the pathologic study. In addition to this, the extension study showed lung metastases requiring initiation of systemic treatment with sunitinib. The patient presented an excellent response to treatment, showing complete clinical and radiological response at 5 months of treatment (RECIST criteria) and a disease-free survival of 48 months until now, without evidence of toxicity. RCC has the potential to metastasize to almost any location, but thyroid and duodenal metastases in RCC are extremely rare. Moreover, this case also highlights the good responses that can be achieved in terms of disease-free survival, low toxicity and quality of life in this new era of therapies against molecular targets

    Predictors and prognosis of paroxysmal atrial fibrillation in general practice in the UK

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    BACKGROUND: Natural history of paroxysmal atrial fibrillation (AF) is not very well documented. Clinical experience suggests that paroxysmal AF could progress to chronic AF with estimates ranging between 15 and 30% over a period of 1–3 years. We performed an epidemiologic study to elucidate the natural history of paroxysmal AF, this study estimated its incidence in a general practice setting, identified associated factors and analyzed the progression into chronic AF as well as the mortality rate. METHODS: Using the UK General Practice Research Database (GPRD), we identified patients aged 40–89 years with a first-recorded episode of paroxysmal AF during 1996. Risk factors were assessed using 525 incident paroxysmal AF cases confirmed by the general practitioner (GP) and a random sample of controls. We follow-up paroxysmal AF patients and estimated their mortality rate and progression to chronic AF. RESULTS: The incidence of paroxysmal AF was 1.0 per 1,000 person-years. Major risk factors for paroxysmal AF were age and prior valvular heart disease, ischaemic heart disease, heart failure and hyperthyroidism. During a mean follow-up of 2.7 years, 70 of 418 paroxysmal AF patients with complete information progressed to chronic AF. Risk factors associated with progression were valvular heart disease (OR 2.7, 95% CI 1.2–6.0) and moderate to high alcohol consumption (OR 3.0, 95% CI 1.1–8.0). Paroxysmal AF patients did not carry an increased risk of mortality, compared to an age and sex matched sample of the general population. There was a suggestion of a small increased risk among patients progressing to chronic AF (RR 1.5, 96% CI 0.8–2.9). CONCLUSION: Paroxysmal AF is a common arrhythmia in the general practice setting, increasing with age and commonly associated with other heart diseases. It sometimes is the initial presentation and then progress to chronic AF. A history of valvular heart disease and alcohol consumption are associated with this progression

    COVID-19 and Dentistry: a Review of Recommendations and Perspectives for Latin America

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    COVID-19 es una enfermedad altamente contagiosa y potencialmente mortal que nos acompañara por largo tiempo. Las profesiones de la salud y la vida en general ha sido afectada de forma significativa en todo lugar del mundo. La odontología ha pasado de una etapa de gran desarrollo clínico a una etapa donde el manejo de barrera de protección, el control de tratamientos y el tiempo asignado a los pacientes cambiará la forma de realizar la profesión. El presente trabajo pretende resumir las indicaciones y recomendaciones basadas en la evidencia disponible y realizar un análisis de la condiciones de salud oral para Latinoamérica en esta época de pandemia.COVID-19 is a profound, highly contagious and life-threatening viral disease that will be with us for a long time. Health Care-related professions and life in its entirety are significantly, and perhaps irreversibly affected, all around the World. COVID-19 is and will continue to transform Dentistry and its practise. Based on the available evidence accrued to date, this work attempts to address such changes, current and anticipated, as well as present recommendations for clinical practise implementation, tailored for Latin/South America, in light of such lifealtering momentous pandemic

    NSAID Use Selectively Increases the Risk of Non-Fatal Myocardial Infarction: A Systematic Review of Randomised Trials and Observational Studies

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    Recent clinical trials and observational studies have reported increased coronary events associated with non steroidal anti-inflammatory drugs (NSAIDs). There appeared to be a disproportionate increase in non-fatal versus fatal events, however, numbers of fatal events in individual studies were too small, and event rates too low, to be meaningful.We undertook a pooled analysis to investigate the effect of NSAIDs on myocardial infarction (MI) risk with the specific aim to differentiate non-fatal from fatal events.We searched Pubmed (January, 1990 to March, 2010) for observational studies and randomised controlled trials that assessed the effect of NSAIDs (traditional or selective COX-2 inhibitors [coxibs]) on MI incidence separately for fatal and non-fatal events. Summary estimates of relative risk (RR) for non-fatal and fatal MIs were calculated with a random effects model.NSAID therapy carried a RR of 1.30 (95% CI, 1.20-1.41) for non-fatal MI with no effect on fatal MI (RR 1.02, 95% CI, 0.89-1.17) in six observational studies. Overall, the risk increase for non-fatal MI was 25% higher (95% CI, 11%-42%) than for fatal MI. The two studies that included only individuals with prior cardiovascular disease presented risk estimates for non-fatal MI on average 58% greater (95% CI, 26%-98%) than those for fatal MI. In nine randomised controlled trials, all investigating coxibs, the pooled RR estimate for non-fatal MI was 1.61 (95% CI, 1.04-2.50) and 0.86 (95% CI 0.51-1.47) for fatal MIs.NSAID use increases the risk of non-fatal MI with no substantial effect on fatal events. Such differential effects, with potentially distinct underlying pathology may provide insights into NSAID-induced coronary pathology. We studied the association between the use of nonsteroidal anti-inflammatory drugs (NSAIDs) and the risk of myocardial infarction (MI), separating non-fatal from fatal events, summarizing the evidence from both observational studies and randomised controlled trials. An increased risk of non-fatal MI was clearly found in both types of studies while use of NSAID did not confer an increased risk of fatal MI. Our findings provide support for the concept that thrombi generated under NSAID treatment could be different from spontaneous thrombi

    Experiencias docentes potenciando los resultados de aprendizaje: 3ra. Jornada de innovación e investigación educativa de Unapec 2016

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    En la Universidad APEC (UNAPEC) se concibe la tercera jornada de innovación e investigación educativa como un espacio de reflexión pedagógica para el intercambio de saberes, experiencias y prácticas docentes orientadas a la mejora de los resultados de aprendizaje. Para esta ocasión, la misma tiene como objetivo proporcionar el diálogo profesional y el intercambio académico a fin de construir un entendimiento común sobre el proceso de mejora continua de la institución y promover la innovación e investigación como parte de la cultura de calidad, focalizada en el aprendizaje de los estudiantes
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