879 research outputs found

    Experimental study of the electromagnetic induction in coils: Dependence on the electric current

    Get PDF
    En este artículo se muestran un conjunto de sencillas experiencias de laboratorio que ilustran el fenómeno de la inducción electromagnética. El dispositivo experimental, análogo a un transformador, está formado por dos bobinas magnéticamente acopladas conectadas a un generador de corriente alterna sinusoidal de frecuencia variable. Midiendo la tensión inducida en la bobina del secundario en función de la corriente que hay en la bobina del primario se obtiene una dependencia lineal. Los resultados obtenidos concuerdan bastante bien, teniendo en cuenta los intervalos de error, con las predicciones teóricas de la ley de Faraday-Henry. Para la predicción teórica se ha tenido en cuenta el tamaño finito de ambas bobinas calculando el flujo magnético mediante una sencilla integral.Uno de los autores, A. Beléndez, agradece al Vicerrectorado de Tecnologías de la Información de la Universidad de Alicante el apoyo prestado a través del proyecto GITE-09006-UA

    Evaluación del uso de dispositivos interactivos de respuesta (clickers) en Física Médica

    Get PDF
    La asignatura Bases Físicas de la Medicina se imparte durante el primer cuatrimestre primer curso de la Licenciatura en Medicina con una carga docente de 6 créditos. El docente, novedoso y acorde con el Espacio Europeo de Educación Superior (EEES) comienzo de la Facultad en 1998, pone al alumnado en el centro del proceso de enseñanza/aprendizaje. En este contexto, se han utilizado dispositivos personales de respuesta o clickers, no solo para incrementar la participación sino también para permitir alumnos evaluarse entre sí. En el presente trabajo se introducen sus principales aplicaciones, sugiriendo tácticas mejorar sus beneficios y optimizar su uso. También se detallan las primeras impresiones muy positivas de alumnos y profesores. Un total de 95 alumnos participaron en el estudio. 97,9% respondieron que los clickers habían hecho las sesiones más entretenidas, el consideraron que su uso les había ayudado a seguir mejor la clase, y el 87,4% creen participación se había incrementado. En cuanto a la evaluación de sus compañeros, el 45,3% trató de realizar calificaciones objetivas, el 31,6% siempre calificó con buenas notas independientemente de la calidad trabajo presentado. Después de algunas sesiones, el 17,9% demandó presentaciones y calificaron de manera más exigente y objetiva. Los alumnos sugirieron uso de los clickers en otras asignaturas con el fin de incrementar su motivación.Medical Physics is a four-month long subject taught during the first year of the degree in Medicine with a teaching load of 6 credits. The teaching method, new and in line with the European Higher Education Area (EHEA) since the beginning of the Faculty in 1998, puts the students at the center of teaching-learning process. In this context, we have used remote response devices or clickers, not only to increase the students participation but also to allow them to evaluate each other. In this paper we introduce its main applications, suggesting tactics to improve profits and optimize their use. It also details the very positive first impressions of students and teachers. A total of 95 students participated in the study. 97.9% responded that clickers had made the sessions most entertaining, 84.2% considered that their use had helped them to follow the class better, and 87.4% believe that their participation had increased. As for the evaluation of their classmates, 45.3% tried to make objective qualifications, 31.6% always scored good marks regardless of the quality of the submitted work. After a few sessions, 17.9% demanded better performances and marked in a more qualified and objective way. The students suggested the use of clickers in other subjects in order to increase their motivation

    Estudio experimental de la inducción electromagnética entre dos bobinas: dependencia con la corriente eléctrica

    Get PDF
    En este artículo se muestran un conjunto de sencillas experiencias de laboratorio que ilustran el fenómeno de la inducción electromagnética. El dispositivo experimental, análogo a un transformador, está formado por dos bobinas magnéticamente acopladas conectadas a un generador de corriente alterna sinusoidal de frecuencia variable. Midiendo la tensión inducida en la bobina del secundario en función de la corriente que hay en la bobina del primario se obtiene una dependencia lineal. Los resultados obtenidos concuerdan bastante bien, teniendo en cuenta los intervalos de error, con las predicciones teóricas de la ley de Faraday-Henry. Para la predicción teórica se ha tenido en cuenta el tamaño finito de ambas bobinas calculando el flujo magnético mediante una sencilla integral.In this paper, it is shown a set of simple experiences that inform about the phenomenon of electromagnetic induction. The electrical assembly is made of two coils magnetically coupled, analogous to an electrical transformer, connected to a variable frequency AC generator. If we measure the voltage induced in the secondary coil based on the current of the primary coil it is obtained a linear dependence. The obtained results agree quite well with, considering the error ranges, the theoretical predictions of the Faraday-Henry’s law. In the theoretical predictions we have also taken into account the finite size of both coils calculating the magnetic flux through an easy integral.Uno de los autores, A. Beléndez, agradece al Vicerrectorado de Tecnologías de la Información de la Universidad de Alicante el apoyo prestado a través del proyecto GITE- 09006-UA

    Metabolic and mitochondria alterations induced by SARS-CoV-2 accessory proteins ORF3a, ORF9b, ORF9c and ORF10

    Get PDF
    Antiviral signaling, immune response and cell metabolism in human body are dysregulated by SARS-CoV-2, the causative agent of the COVID-19. Here, we show that SARS-CoV-2 accessory proteins ORF3a, ORF9b, ORF9c and ORF10 induce a significant mitochondrial and metabolic reprogramming in A549 lung epithelial cells. While all four ORFs caused mitochondrial fragmentation and altered mitochondrial function, only ORF3a and ORF9c induced a marked structural alteration in mitochondrial cristae. ORF9b, ORF9c and ORF10 induced largely overlapping transcriptomes. In contrast, ORF3a induced a distinct transcriptome, including the downregulation of numerous genes for proteins with critical mitochondrial functions and morphology. Genome-Scale Metabolic Models predicted common and private metabolic flux reprogramming, notably a depressed amino acid metabolism, and an enhanced metabolism of specific lipids distinctly induced by ORF3a. These findings reveal metabolic dependencies and vulnerabilities prompted by SARS-CoV-2 accessory proteins that may be exploited to identify new targets for intervention.This research work was funded by the European Commission – NextGenerationEU (Regulation EU 2020/2094), through CSIC's Global Health Platform (PTI+ Salud Global) (COVID-19-117 and SGL2103015), Junta de Andalucía (CV20-20089), Spanish Ministry of Science project (PID2021-123399OB-I00), the Agency for Management of University and Research Grants from Generalitat de Catalunya-AGAUR (2020PANDE00048 and 2021SGR00350) and ICREA foundation (ICREA-Academia-2021 to MC) of Generalitat de Catalunya, and an AESi grant of the Instituto de Salud Carlos III (PI20CIII-00014). TGG is recipient of a Ramón y Cajal contract funded by MCIN/AEU/10.13039/501100011033 and NextGeneration EU/PRTR.N

    Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

    Full text link
    Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

    Juxtaposing BTE and ATE – on the role of the European insurance industry in funding civil litigation

    Get PDF
    One of the ways in which legal services are financed, and indeed shaped, is through private insurance arrangement. Two contrasting types of legal expenses insurance contracts (LEI) seem to dominate in Europe: before the event (BTE) and after the event (ATE) legal expenses insurance. Notwithstanding institutional differences between different legal systems, BTE and ATE insurance arrangements may be instrumental if government policy is geared towards strengthening a market-oriented system of financing access to justice for individuals and business. At the same time, emphasizing the role of a private industry as a keeper of the gates to justice raises issues of accountability and transparency, not readily reconcilable with demands of competition. Moreover, multiple actors (clients, lawyers, courts, insurers) are involved, causing behavioural dynamics which are not easily predicted or influenced. Against this background, this paper looks into BTE and ATE arrangements by analysing the particularities of BTE and ATE arrangements currently available in some European jurisdictions and by painting a picture of their respective markets and legal contexts. This allows for some reflection on the performance of BTE and ATE providers as both financiers and keepers. Two issues emerge from the analysis that are worthy of some further reflection. Firstly, there is the problematic long-term sustainability of some ATE products. Secondly, the challenges faced by policymakers that would like to nudge consumers into voluntarily taking out BTE LEI

    Search for stop and higgsino production using diphoton Higgs boson decays

    Get PDF
    Results are presented of a search for a "natural" supersymmetry scenario with gauge mediated symmetry breaking. It is assumed that only the supersymmetric partners of the top-quark (stop) and the Higgs boson (higgsino) are accessible. Events are examined in which there are two photons forming a Higgs boson candidate, and at least two b-quark jets. In 19.7 inverse femtobarns of proton-proton collision data at sqrt(s) = 8 TeV, recorded in the CMS experiment, no evidence of a signal is found and lower limits at the 95% confidence level are set, excluding the stop mass below 360 to 410 GeV, depending on the higgsino mass

    Penilaian Kinerja Keuangan Koperasi di Kabupaten Pelalawan

    Full text link
    This paper describe development and financial performance of cooperative in District Pelalawan among 2007 - 2008. Studies on primary and secondary cooperative in 12 sub-districts. Method in this stady use performance measuring of productivity, efficiency, growth, liquidity, and solvability of cooperative. Productivity of cooperative in Pelalawan was highly but efficiency still low. Profit and income were highly, even liquidity of cooperative very high, and solvability was good

    Severe early onset preeclampsia: short and long term clinical, psychosocial and biochemical aspects

    Get PDF
    Preeclampsia is a pregnancy specific disorder commonly defined as de novo hypertension and proteinuria after 20 weeks gestational age. It occurs in approximately 3-5% of pregnancies and it is still a major cause of both foetal and maternal morbidity and mortality worldwide1. As extensive research has not yet elucidated the aetiology of preeclampsia, there are no rational preventive or therapeutic interventions available. The only rational treatment is delivery, which benefits the mother but is not in the interest of the foetus, if remote from term. Early onset preeclampsia (<32 weeks’ gestational age) occurs in less than 1% of pregnancies. It is, however often associated with maternal morbidity as the risk of progression to severe maternal disease is inversely related with gestational age at onset2. Resulting prematurity is therefore the main cause of neonatal mortality and morbidity in patients with severe preeclampsia3. Although the discussion is ongoing, perinatal survival is suggested to be increased in patients with preterm preeclampsia by expectant, non-interventional management. This temporising treatment option to lengthen pregnancy includes the use of antihypertensive medication to control hypertension, magnesium sulphate to prevent eclampsia and corticosteroids to enhance foetal lung maturity4. With optimal maternal haemodynamic status and reassuring foetal condition this results on average in an extension of 2 weeks. Prolongation of these pregnancies is a great challenge for clinicians to balance between potential maternal risks on one the eve hand and possible foetal benefits on the other. Clinical controversies regarding prolongation of preterm preeclamptic pregnancies still exist – also taking into account that preeclampsia is the leading cause of maternal mortality in the Netherlands5 - a debate which is even more pronounced in very preterm pregnancies with questionable foetal viability6-9. Do maternal risks of prolongation of these very early pregnancies outweigh the chances of neonatal survival? Counselling of women with very early onset preeclampsia not only comprises of knowledge of the outcome of those particular pregnancies, but also knowledge of outcomes of future pregnancies of these women is of major clinical importance. This thesis opens with a review of the literature on identifiable risk factors of preeclampsia

    Gestión del conocimiento: perspectiva multidisciplinaria. Volumen 12

    Get PDF
    El libro “Gestión del Conocimiento. Perspectiva Multidisciplinaria”, Volumen 12, de la Colección Unión Global, es resultado de investigaciones. Los capítulos del libro, son resultados de investigaciones desarrolladas por sus autores. El libro cuenta con el apoyo de los grupos de investigación: Universidad Sur del Lago “Jesús María Semprúm” (UNESUR), Zulia – Venezuela; Universidad Politécnica Territorial de Falcón Alonso Gamero (UPTAG), Falcón – Venezuela; Universidad Politécnica Territorial de Mérida Kleber Ramírez (UPTM), Mérida – Venezuela; Universidad Guanajuato (UG) - Campus Celaya - Salvatierra - Cuerpo Académico de Biodesarrollo y Bioeconomía en las Organizaciones y Políticas Públicas (C.A.B.B.O.P.P), Guanajuato – México; Centro de Altos Estudios de Venezuela (CEALEVE), Zulia – Venezuela, Centro Integral de Formación Educativa Especializada del Sur (CIFE - SUR) - Zulia - Venezuela, Centro de Investigaciones Internacionales SAS (CIN), Antioquia - Colombia.y diferentes grupos de investigación del ámbito nacional e internacional que hoy se unen para estrechar vínculos investigativos, para que sus aportes científicos formen parte de los libros que se publiquen en formatos digital e impreso
    corecore