37 research outputs found

    Modelado atomístico de las implantaciones de alta energía en silicio

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    La implantación iónica en Si tiene un amplio rango de aplicaciones en el sector tecnológico, desde microprocesadores hasta células solares. Los simuladores atomísticos existentes describen correctamente este proceso en el rango de bajas y medias energías de implantación pero no en el de altas energías. En el presente trabajo, se revisan los modelos que describen los diversos mecanismos por los que el ion pierde energía a medida que atraviesa el material blanco para comprender la física que hay detrás, especialmente a altas energías. Para ello, se analizarán los datos experimentales proporcionados por la empresa Applied Materials y se evaluarán las diferentes pérdidas energéticas que sufre el ion a lo largo de toda su trayectoria.Ion implantation in Si has a wide range of applications in the technological sector, from microprocessors to solar cells. Current simulators describe this process correctly in the range of low and medium implantation energies but not in the high energy range. In the present work, we review the models that describe the several mechanisms by which the ion loses energy as it passes through the target material to understand the physics behind it, especially at high energies. To do this, the experimental data provided by the company Applied Materials will be analyzed and the different energy losses suffered by the ion throughout its entire trajectory will be evaluated.Departamento de Electricidad y ElectrónicaGrado en Físic

    Ciudades en pie de guerra. La organización militar de las sociedades urbanas en los reinos hispánicos en la Baja Edad Media: Castilla, Aragón y Navarra.

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    Lo habitual a la hora de imaginar cómo eran las guerras en la Edad Media es pensar que, los guerreros, eran un grupo de caballeros procedentes de las aristocracias dirigidos por su monarca y grupos de soldados religiosos de las órdenes militares. Lo cual no es erróneo, sino incompleto. Además de estos individuos mitificados, también existía otro sector de la población que estaba dispuesto a que luchar. Se trata de los habitantes de las ciudades y núcleos urbanos que, armados, organizaban grupos de combatientes a través de las milicias urbanas bajo las órdenes de las autoridades locales y que hacían la guerra junto al rey o actuaban de manera autónoma. Estas milicias se veían compuestas por vecinos, artesanos, campesinos y oligarcas locales registrados en las parroquias y colaciones que, obtuvieron derechos y obligaciones gracias a la legislación redactada en los fueros medievales. De esta manera pudieron formar parte de los ejércitos reales, movilizarse de manera independiente con fines y objetivos propios, defender sus posesiones de ataques enemigos o solventar los problemas que surgían dentro de sus propias comunidades.<br /

    Atomistic simulations of acceptor removal in p-type Si irradiated with neutrons

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    Producción CientíficaThe effective dopant concentration in p-type Si detectors reduces with irradiation fluence at low fluences due to the acceptor removal process, which degrades detector performance and shortens its lifetime. This effect has been experimentally characterized and parametrized, but its microscopic origin is still unknown. We use atomistic simulations to gain insight into acceptor removal in neutron irradiation by modeling damage generation and defect-dopant interactions. We analyze the effect on dopant deactivation of the Si di- and tri-interstitial diffusion, the inhomogeneity of irradiation damage and the wafer temperature rise during irradiation. We characterize defect generation rates and identify the relevant defect-dopant interactions. Acceptor removal occurs mainly through the formation of Bi pairs and small boron-interstitial clusters, and it is limited by the availability of mobile Si interstitials. The presence of impurities (O, C) modifies B-complexes favoring the formation of BiO, but has a limited effect on the amount of removed acceptors.Ministerio de Ciencia e Innovación (project PID2020-115118GB-I00

    Nosocomial Vs. Community-Acquired Infective Endocarditis in Spain: Location, Trends, Clinical Presentation, Etiology, and Survival in the 21st Century

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    Major changes have occurred in the epidemiology and etiology of infective endocarditis (IE). Nevertheless, the differences between nosocomial infective endocarditis (NIE) and community-acquired infective endocarditis (CIE) have not been addressed in a population-based study. We conducted a retrospective, nationwide, temporal trend study from 1997 to 2014 analyzing the epidemiology, clinical, geographical, meteorological characteristics of patients diagnosed with IE in Spain, to distinguish NIE from CIE. Among 25,952 patients with IE (62.2 ± 18·6 years; 65.9% men), 45.9% had NIE. The incidence of IE increased from 2.83 to 3.73 due to the NIE incidence increment with a decline in CIE. Patients with NIE were older (63.8 years vs. 60.8 years, p < 0·001), presented a higher Charlson index (1.22 vs. 1.03, p < 0.001), a greater history of implanted cardiac devices (8.7% vs. 4.6%, p < 0.001), and higher mortality (31.5% vs. 21.7%, p < 0.001). The most frequent microorganism for both NIE and CIE was Staphylococcus (p < 0.001), and the North reported a higher incidence (p < 0.001). Risk factors of mortality for NIE were age, Charlson index, hemodialysis, shock, heart failure, and stroke. Risk factors for CIE included female sex, renal disease, and cardiac-device carriers. The etiology of IE shifted from community origins to mostly nosocomial-associated infections. Higher morbidity, mortality, and poorer outcomes are associated with NIE.This research received no external funding. The authors thank Consejería de Educación, Junta de Castilla y León, Spain (reference: VA161G18), for covering the publication charges of this article.S

    HGF, IL-1α, and IL-27 Are Robust Biomarkers in Early Severity Stratification of COVID-19 Patients

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    Producción CientíficaPneumonia is the leading cause of hospital admission and mortality in coronavirus disease 2019 (COVID-19). We aimed to identify the cytokines responsible for lung damage and mortality. We prospectively recruited 108 COVID-19 patients between March and April 2020 and divided them into four groups according to the severity of respiratory symptoms. Twenty-eight healthy volunteers were used for normalization of the results. Multiple cytokines showed statistically significant differences between mild and critical patients. High HGF levels were associated with the critical group (OR = 3.51; p < 0.001; 95%CI = 1.95–6.33). Moreover, high IL-1α (OR = 1.36; p = 0.01; 95%CI = 1.07–1.73) and low IL-27 (OR = 0.58; p < 0.005; 95%CI = 0.39–0.85) greatly increased the risk of ending up in the severe group. This model was especially sensitive in order to predict critical status (AUC = 0.794; specificity = 69.74%; sensitivity = 81.25%). Furthermore, high levels of HGF and IL-1α showed significant results in the survival analysis (p = 0.033 and p = 0.011, respectively). HGF, IL-1α, and IL 27 at hospital admission were strongly associated with severe/critical COVID-19 patients and therefore are excellent predictors of bad prognosis. HGF and IL-1α were also mortality biomarkers.Instituto de Salud Carlos III (grant COV20/00491

    Can the Cytokine Profile According to ABO Blood Groups Be Related to Worse Outcome in COVID-19 Patients? Yes, They Can

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    Producción CientíficaSevere status of coronavirus disease 2019 (COVID-19) is extremely associated to cytokine release. Moreover, it has been suggested that blood group is also associated with the prevalence and severity of this disease. However, the relationship between the cytokine profile and blood group remains unclear in COVID-19 patients. In this sense, we prospectively recruited 108 COVID-19 patients between March and April 2020 and divided according to ABO blood group. For the analysis of 45 cytokines, plasma samples were collected in the time of admission to hospital ward or intensive care unit and at the sixth day after hospital admission. The results show that there was a risk of more than two times lower of mechanical ventilation or death in patients with blood group O (log rank: p = 0.042). At first time, all statistically significant cytokine levels, except from hepatocyte growth factor, were higher in O blood group patients meanwhile the second time showed a significant drop, between 20% and 40%. In contrast, A/B/AB group presented a maintenance of cytokine levels during time. Hepatocyte growth factor showed a significant association with intubation or mortality risk in non-O blood group patients (OR: 4.229, 95% CI (2.064–8.665), p < 0.001) and also was the only one bad prognosis biomarker in O blood group patients (OR: 8.852, 95% CI (1.540–50.878), p = 0.015). Therefore, higher cytokine levels in O blood group are associated with a better outcome than A/B/AB group in COVID-19 patients.Instituto de Salud Carlos III (grant COV20/00491)Junta de Castilla y León (grant 18IGOF

    Obstetric outcomes of sars-cov-2 infection in asymptomatic pregnant women

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    Altres ajuts: Fondo Europeo de Desarrollo Regional (FEDER)Around two percent of asymptomatic women in labor test positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Spain. Families and care providers face childbirth with uncertainty. We determined if SARS-CoV-2 infection at delivery among asymptomatic mothers had different obstetric outcomes compared to negative patients. This was a multicenter prospective study based on universal antenatal screening for SARS-CoV-2 infection. A total of 42 hospitals tested women admitted for delivery using polymerase chain reaction, from March to May 2020. We included positive mothers and a sample of negative mothers asymptomatic throughout the antenatal period, with 6-week postpartum follow-up. Association between SARS-CoV-2 and obstetric outcomes was evaluated by multivariate logistic regression analyses. In total, 174 asymptomatic SARS-CoV-2 positive pregnancies were compared with 430 asymptomatic negative pregnancies. No differences were observed between both groups in key maternal and neonatal outcomes at delivery and follow-up, with the exception of prelabor rupture of membranes at term (adjusted odds ratio 1.88, 95% confidence interval 1.13-3.11; p = 0.015). Asymptomatic SARS-CoV-2 positive mothers have higher odds of prelabor rupture of membranes at term, without an increase in perinatal complications, compared to negative mothers. Pregnant women testing positive for SARS-CoV-2 at admission for delivery should be reassured by their healthcare workers in the absence of symptoms

    ¿Necesitamos un asistente virtual para apoyo y formación permanente de profesores, alumnos y egresados en nuestra página web?

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    Se trata de identificar las necesidades no resueltas y otras cuestiones de interés, y proponer la utilización del asistente virtual como herramienta de apoyo en el acceso, la formación presente y futura, con carácter permanente, al alumno y al profesor; ello supone su utilidad en el momento presente y en el futuro, como herramienta de formación y acceso permanente. La originalidad del Proyecto estriba precisamente en el planteamiento de la incorporación de la asistencia virtual e inteligencia artificial para la asistencia y apoyo a los alumnos y profesores. El uso de la tecnología es cada vez más mayor, y puede revertir en beneficio al alumno desde una perspectiva más amplia de la que un profesor individualmente puede ofrecerle; se lograría así el acceso a la información con una intervención humana mínima, en cualquier momento y en cuestiones generales de amplio espectro, al que cada profesor en su especialidad no llega a abarcar, y los programas voluntarios de mentorías tampoco

    Treatment with tocilizumab or corticosteroids for COVID-19 patients with hyperinflammatory state: a multicentre cohort study (SAM-COVID-19)

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    Objectives: The objective of this study was to estimate the association between tocilizumab or corticosteroids and the risk of intubation or death in patients with coronavirus disease 19 (COVID-19) with a hyperinflammatory state according to clinical and laboratory parameters. Methods: A cohort study was performed in 60 Spanish hospitals including 778 patients with COVID-19 and clinical and laboratory data indicative of a hyperinflammatory state. Treatment was mainly with tocilizumab, an intermediate-high dose of corticosteroids (IHDC), a pulse dose of corticosteroids (PDC), combination therapy, or no treatment. Primary outcome was intubation or death; follow-up was 21 days. Propensity score-adjusted estimations using Cox regression (logistic regression if needed) were calculated. Propensity scores were used as confounders, matching variables and for the inverse probability of treatment weights (IPTWs). Results: In all, 88, 117, 78 and 151 patients treated with tocilizumab, IHDC, PDC, and combination therapy, respectively, were compared with 344 untreated patients. The primary endpoint occurred in 10 (11.4%), 27 (23.1%), 12 (15.4%), 40 (25.6%) and 69 (21.1%), respectively. The IPTW-based hazard ratios (odds ratio for combination therapy) for the primary endpoint were 0.32 (95%CI 0.22-0.47; p < 0.001) for tocilizumab, 0.82 (0.71-1.30; p 0.82) for IHDC, 0.61 (0.43-0.86; p 0.006) for PDC, and 1.17 (0.86-1.58; p 0.30) for combination therapy. Other applications of the propensity score provided similar results, but were not significant for PDC. Tocilizumab was also associated with lower hazard of death alone in IPTW analysis (0.07; 0.02-0.17; p < 0.001). Conclusions: Tocilizumab might be useful in COVID-19 patients with a hyperinflammatory state and should be prioritized for randomized trials in this situatio
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