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In this work, an assessment of the performance of thermo-oxidated Jatropha oil as a lubricant for actual wet clutch materials was performed and compared with a commercial automatic transmission fluid. For this, Jatropha oil, a commercial automatic transmission fluid and a blend of 20 vol% Jatropha oil–80 vol% automatic transmission fluid were subjected to thermo-oxidative aging at 26 °C and 100 °C, followed by a pin-on-disk testing with disk samples from an actual wet clutch. Evaluation of the film thickness at the sliding interface resulted in a boundary lubrication regime for all the tests. The changes in oxidation, viscosity, and a viscosity index of the samples were evaluated along with friction coefficients at various sliding speeds. Jatropha oil was the most sensitive to thermo-oxidation. Jatropha oil and the blend showed a higher viscosity increase than automatic transmission fluid with thermo-oxidation, while the viscosity index of all oils was decreased considerably, Jatropha oil and the blend being the most reduced. Finally, the anti-shudder property, as measured by the change in the friction coefficient with a sliding speed, of Jatropha oil and automatic transmission fluid was improved by thermo-oxidation at 26 °C but worsened at 100 °C, meanwhile it was barely affected in the blend. Therefore, these results indicate that using pure Jatropha oil as automatic transmission fluid would be unsuitable, but blending it with automatic transmission fluids in specific proportions may be apposite for improving the friction properties of wet clutches even under thermo-oxidative conditions.

This paper focuses on Dressel 20 stamps found on the Tyne-Solway isthmus and Hadrian's Wall from the first to the fourth century AD. The aim is to describe olive oil imports to the limes of Britannia by focusing on the distribution of stamps along the wall, their location and the most common stamp dies. This research also provides an accurate analysis of olive oil exportation by studying the workshops (figlinae) where these stamps were produced, and by describing the economic activity of figlinae from a chronological and administrative standpoint.

El presente trabajo está dirigido a conocer las necesidades de asesoramiento o ayuda que el profesorado de infantil, primaria y secundaria de nuestro país demanda de profesionales expertos en relación con su trabajo como profesor al objeto de que esta información sirva de referencia en la toma de medidas adecuadas en orden a satisfacer esas necesidades en pro de la calidad de la educación proporcionada por nuestro sistema educativo. Los datos están basados sobre una muestra de 1464 profesores de ámbito nacional y se ha analizado a nivel global y en función del género, de la antigüedad profesional y de la etapa educativa en la que ejercen su docencia. Los resultados hacen referencia a diversas situaciones docentes y sus implicaciones en la calidad educativa han sido analizadas. This study seeks to find out the advice or consulting needs that preschool, elementary and secondary teachers of our country demand of professional consultants concerning their job as teachers so that information serve as a point of reference for the adoption of appropriate measures to satisfy those needs, favouring the quality of education provided by our educational system. Data are based on a nationwide sample of 1464 teachers and have been analyzed at a global level and according to gender, professional seniority and the educational level where they teach. Results refer to several teaching situations and their implications for the education quality are analyzed.

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Objectives: To analyse the effect of zinc supplementation in growth and nutritional status of a homogeneous group of newborns with intra uterine growth retardation and asymmetric growth. The effect of changes of zinc status on growth and leptin serum concentrations was also analysed. Population and methods: A double blind, randomised clinical trial was designed in order to detect differences in growth between zinc and placebo groups during the first 6 months of life. 31 infants were included either to the zinc group (n = 14) (38.8 ± 1.4 weeks GA, 2,171 ± 253 g body weight) or the placebo group (n = 17) (38.9 ± 1.1 weeks GA, 2,249 ± 220 g body weight). The zinc group received a supplement of 3 mg elemental zinc per day (as zinc sulphate). Results: There were not significant differences between groups for anthropometric measurements through the study period. We found a significant effect of the study group, in hair zinc concentrations, but not in serum zinc concentrations; post-hoc comparisons for hair zinc revealed that there were significant differences between groups at 1, 2, and 6 months of age. Changes in serum and hair zinc concentrations from baseline to 6 months, showed significant correlations with changes in weight/age and length/age z-scores, in the supplement group. Changes in leptin serum concentrations during follow-up, showed significant correlations with changes in sum of 4 skinfolds and weight/age z-score, in the placebo group. Changes in hair zinc concentration through the study period showed significant correlations with changes in leptin serum concentrations from baseline to 6 months of follow-up. Conclusions: In a homogeneous group of intra uterine growth retardation infants with asymmetric growth, 3 mg/day zinc supplementation do not show significant improvements in weight and length growth. Changes in zinc status were related with changes in weight and length during the first 6 months of life. Changes in leptin serum concentrations were related with changes in the anthropometric indices of body fat accretion. Objetivos: Valorar el efecto de la suplementación con cinc en el crecimiento y estado nutricional de un grupo homogéneo de recién nacidos con retraso de crecimiento intra-uterino asimétrico. También se analizó el efecto de los cambios en el status del cinc en el crecimiento y las concentraciones séricas de leptina. Población y método: Se diseñó un ensayo clínico randomizado y doble ciego, con el fin de detectar diferencias en el crecimiento entre los grupos recibiendo cinc o placebo, durante los seis primeros meses de vida. 31 niños fueron incluidos en el grupo cinc (n = 14) (38,8 ± 1,4 semanas edad gestacional, 2.171 ± 253 g peso) o grupo placebo (n = 17) (38,9 ± 1.1 semanas edad gestacional, 2.249 ± 220 g peso). El grupo cinc recibió un suplemento de 3 mg de cinc elemental por día (en forma de sulfato de cinc). Resultados: No hubo diferencias significativas entre ambos grupos en cuanto a las medidas antropométricas a lo largo del período de estudio. Se observó un efecto significativo del grupo de estudio, en las concentraciones de cinc en el pelo, pero no en las concentraciones séricas de cinc; las comparaciones post-hoc para el cinc del pelo pusieron de manifiesto que había diferencias significativas entre los grupos, en los meses 1, 2 y 6 de edad. Los cambios en las concentraciones de cinc en el suero y en el pelo, desde el inicio del estudio hasta los 6 meses, mostraron correlaciones estadísticamente significativas con los cambios en peso/edad y longitud/edad (puntuación típica), en el grupo que recibió el suplemento de cinc. Los cambios en las concentraciones séricas de leptina durante el seguimiento, mostraron correlaciones estadísticamente significativas para la suma de 4 pliegues y para peso/edad (puntuación típica), en el grupo placebo. Los cambios en las concentraciones de cinc en el pelo mostraron correlaciones estadísticamente significativas con los cambios en las concentraciones séricas de leptina, desde el inicio del estudio hasta los 6 meses de seguimiento. Conclusiones: En un grupo homogéneo de niños con retraso de crecimiento intra-uterino asimétrico, el suplemento de cinc a una dosis de 3 mg/día, no origina mejora significativa en el crecimiento en peso y longitud. Los cambios en el status de cinc se relacionaron con los cambios en peso y longitud durante los 6 primeros meses de vida. Los cambios en las concentraciones séricas de leptina se relacionaron con los cambios en los índices antropométricos de acúmulo de grasa corporal.