¿Qué preguntas formulan los estudiantes a partir de la lectura de un texto sobre los dispositivos de seguridad domiciliaria?

En este trabajo presentamos un estudio sobre la formulación de preguntas que realizan estudiantes de nivel secundario, cuando leen un texto ilustrado que se refiere a dispositivos de seguridad domiciliaria. Las preguntas son utilizadas para evaluar la comprensión. Hemos categorizado el corpus de preguntas obtenido en relación con los niveles de representación cognitiva y según se refieran a objetos, procesos y mecanismos causales. Comprobamos que cuando los estudiantes detectan obstáculos en la comprensión formulan preguntas y en éstas ha primado el interés por conocer los elementos de la situación física, las ventajas de los dispositivos y las relaciones causales

Electrochemical Estimation of the Corrosion Rate of Magnesium/Aluminium Alloys

The corrosion rate of AZ31, AZ80, and AZ91D magnesium/aluminium alloys immersed in 3.5 wt.% NaCl was determined comparing gravimetric and electrochemical measurements. The findings revealed that, for all investigated materials, a fraction of the metallic surface exposed to the corrosive medium did not reveal a normal electrochemical response to the applied signal. This may be associated with phenomena such as partial disintegration of specimens into fine metallic particles, electrochemical formation of ions, and/or anomalous chemical attack occurring simultaneously with the normal electrochemical corrosion attack. The abnormal electrochemical behaviour was more evident for lower amounts of aluminium in the bulk composition of the investigated materials. Thus, the electrochemical estimates of pure Mg and the AZ31 alloy were not reliable and tended to underestimate corrosion losses.Peer Reviewe

Large current-induced broadening of the superconducting transition in Mo/Au transition edge sensors

The R(T, I) shape of the superconducting transition in transition edge sensors (TESs) is of crucial importance to determine their ultimate performance. This paper reports a study of the temperature and current dependences of the transition of Mo/Au TESs, focused on the low resistance region, where these devices preferentially operate. A large broadening of the transition is observed when increasing the applied current. An empirical analytic expression for R(T, I) is found, which describes the transition of devices with different critical temperatures, from R = 0 up to at least 30% R-n (in some cases nearly 80% R-n). Several mechanisms for this behaviour are considered; results show that a current assisted vortex pair unbinding mechanism (Berezinskii-Kosterlitz-Thouless transition) could be the possible origin for this behaviour. Finally, the consequences of the current-induced transition broadening for TES properties and operation are outlined

Correlation between the surface chemistry and the atmospheric corrosion of AZ31, AZ80 and AZ91D magnesium alloys

X-ray photoelectron spectroscopy (XPS) was used in order to investigate the correlation between the surface chemistry and the atmospheric corrosion of AZ31, AZ80 and AZ91D magnesium alloys exposed to 98% relative humidity at 50 °C. Commercially pure magnesium, used as the reference material, revealed MgO, Mg(OH)2 and tracers of magnesium carbonate in the air-formed film. For the AZ80 and AZ91D alloys, the amount of magnesium carbonate formed on the surface reached similar values to those of MgO and Mg(OH)2. A linear relation between the amount of magnesium carbonate formed on the surface and the subsequent corrosion behaviour in the humid environment was found. The AZ80 alloy revealed the highest amount of magnesium carbonate in the air-formed film and the highest atmospheric corrosion resistance, even higher than the AZ91D alloy, indicating that aluminium distribution in the alloy microstructure influenced the amount of magnesium carbonate formedThanks to the MCYT for the financial support given to this work (Project MAT2006-13179-C02-01-02)Peer reviewe

Evaluación de la competencia clínica de tutores de residentes de medicina familiar y comunitaria

ObjetivoDescribir la primera experiencia de una evaluación clínica objetiva y estructurada (ECOE) a tutores de residentes realizada en la comunidad autónoma de AndalucíaDiseñoObservacional descriptivoEmplazamientoUnidad Docente de Medicina Familiar y Comunitaria de HuelvaParticipantesTutores de residentes de medicina familiar y comunitariaMediciones principalesLos componentes competenciales que se consensuaron y ponderaron fueron los siguientes: anamnesis, exploración física, comunicación,habilidades técnicas, manejo, atención a la familia y actividades preventivas. La selección de las 10 situaciones clínicas de las que constaba la prueba se realizó utilizando unos criterios de priorización según la prevalencia, gravedad clínica, importancia de la prevención y del diagnóstico precoz, complejidad del caso, evaluación de la capacidad resolutiva del médico y simplicidad evaluativaResultadosRealizaron la ECOE 13 tutores. La edad media ± desviación estándar de los participantes fue de 42,8 ± 3,64 años. La prueba tuvo un coeficiente de fiabilidad (alfa de Cronbach) de 0,73. Por lo que se refiere a los resultados por participantes, la media global fue de 73 ± 6,2. Al analizar los resultados para los diferentes componentes competenciales, los mejores resultados se obtuvieron en la atención a la familia, la comunicación y las habilidades técnicasConclusionesLas pruebas de evaluación clínica objetiva y estructurada pueden ser útiles para la valoración de los tutores, con el objetivo de orientar su formación en los puntos débiles e incluso para, en un futuro no muy lejano, servir como instrumento para acreditar y reacreditar a los tutores de residentes de medicina familiar y comunitariaObjectivesWe show the first experience of the application of an objetive and structured clinical evaluation (OSCE) procedure to family medicine trainers, that has been carried out in Andalucia. The objective is to use a competence evaluation instrument that, in the short term, will be used not only for trainer accreditation but also for other public sanitary professionalsParticipantsTutors of family and commnity medicine residentsDesignObservational descriptiveSettingEducational unity of family medicinePrincipal measurementsThe competencial components to be assessed are the following: anamnesis, physical exploration, communication, technical skill, management, family attention y preventive activities. The clinical situations were selected using the following priority criteria: prevalence, clinical gravity, prevention and early diagnosis importance, case complexity, doctor's capacity of evaluation and simplicityResultsThirteen family medicine trainers took part in the OSCE. Their average age was 42.8±3.6 years. The test had an overall reliability coefficient (Cronbach's alpha) of 0.73. The overall mean score of the participants was 73±6.2. The best results about the competencial components were family attention, communication and technical skillConclusionsThe OSCE can be a convenient tool for family medical trainer evaluation, helping to orientate their education in the weak points and, in the near future, it can also be used as an instrument do accredit family medicine trainer

¿Qué responden los estudiantes universitarios sobre su eficacia autorreguladora en tareas de aprendizaje?

En este trabajo analizamos las respuestas de estudiantes universitarios de Ciencias sobre sus estrategias de eficacia autorreguladora frente a los obstáculos que encuentran en el aprendizaje en tareas de lectura y de evaluaciones. El cuestionario está basado en el inventario de autoeficacia para el aprendizaje Self-Efficacy for Learning Form, SELF. Con los datos obtenidos efectuamos un análisis factorial para establecer cómo se correlacionan las variables a través del agrupamiento en factores. Los resultados de este estudio exploratorio contribuyen a conocer datos sobre la eficacia autorreguladora de los estudiantes que permitirían planificar actividades de aprendizaje autorreguladas para mejorar sus rendimientos académicos

Nucleotomía percutánea automatizada: experiencia en 425 casos

En el presente trabajo exponemos nuestra experiencia en el tratamiento de la hernia discal lumbar mediante Nucleotomía Percutánea Automatizada. El estudio comprende el periodo de Junio de 1988 a Diciembre de 1992. Se incluyen un total de 425 enfermos de edades comprendidas entre los 18 y 58 años. Los pacientes han sido evaluados a las 6 semanas, a los 3 y a los 6 meses tras la intervención. Los resultados han sido satisfactorios en el 71% de los casos. Solamente hubo una complicación de espondilodiscitis. En el 29% de los casos se obtuvieron malos resultados. Un porcentaje importante de los fracasos, se debieron a una mala selección de los pacientes desde el punto de vista de su perfil psicológico.Our experience using automated percutaneous nucleotomy for treatment for herniated disc is presented. A total of 42 5 patientes, aged between 18 and 58 years and operated from June 88 to December 1992, has been included. Patients were clinically assessed at 6 weeks, 3 months and 6 months after surgery. Satisfactory results were found in 71% of cases. As for complications, there was only a case of discitis. In 29% of patients, the outcome was poor. An important group of failures were due to bad selection of patients regadings psychological profile

IFE Plant Technology Overview and contribution to HiPER proposal

HiPER is the European Project for Laser Fusion that has been able to join 26 institutions and signed under formal government agreement by 6 countries inside the ESFRI Program of the European Union (EU). The project is already extended by EU for two years more (until 2013) after its first preparatory phase from 2008. A large work has been developed in different areas to arrive to a design of repetitive operation of Laser Fusion Reactor, and decisions are envisioned in the next phase of Technology Development or Risk Reduction for Engineering or Power Plant facilities (or both). Chamber design has been very much completed for Engineering phase and starting of preliminary options for Reactor Power Plant have been established and review here

Li distribution characterization in Li-ion batteries positive electrodes containing LixNi0.8Co0.15Al0.05O2 secondary particles

The elemental distribution of as-received (non-charged) and charged Li-ion battery positive electrodes containing LixNi0.8Co0.15Al0.05O2 (0.75 ? x ? 1.0) microparticles as active material is characterized by combining μ-PIXE and μ-PIGE techniques. PIGE measurements evidence that the Li distribution is inhomogeneous (existence of Li-rich and Li-depleted regions) in as-received electrodes corresponding with the distribution of secondary particles but it is homogeneous within the studied individual secondary micro-particles. The dependence of the Li distribution on electrode thickness and on charging conditions is characterized by measuring the Li distribution maps in specifically fabricated cross-sectional samples. These data show that decreasing the electrode thickness down to 35 μm and charging the batteries at slow rate give rise to more homogeneous Li depth profiles