Development of Interactive Materials by Engineering Students Using the Descartes Applets.

In a degree course such as Forestry Engineering, the general teaching objectives consist of explaining and helping students to understand the principles of Mechanics. For some time now we have encountered significant difficulties in teaching this subject due to the students' lack of motivation and to their insufficient prior preparation for the topic. If we add to this the discipline's inherent complexity and the students' preconceptions about the subject, these teaching difficulties become considerable. For this reason a series of didactic activities have been introduced sequentially in the teaching of this subject. This work describes the methodology, procedure and results for the action of developing a work project in groups using Descartes software. The results of this experiment can be considered very positive. Some of the critical preconceptions for learning the subject can be corrected, and the tutoring process in the classroom contributes to an improvement in teacherstudent communication. Since this scheme was established, the number of students taking part each academic year has increased, and this is the group with the greatest percentage of passing scores

Antioxidant activity of isolated compounds in non-volatile residue from orange essential oil

6 páginas, 3 figuras.[ES] Existe un creciente interés en la industria alimentaria y en la medicina preventiva por la búsqueda de «antioxidantes naturales», por lo que nos planteamos evaluar la actividad antioxidante del residuo no volátil del aceite esencial de naranja contra la oxidación del aceite de oliva sin retinar y de reciente extracción. Mediante destilación del aceite esencial de naranja se obtuvo el residuo no-volátil, el cual se fraccionó en columna de silica gel 60. La actividad antioxidante fue medida por el valor de peróxidos producidos por el aceite de oliva al provocar la oxidación por calentamiento a 70 °C durante 48 h. Se aislaron seis compuestos mediante H PLC preparativo de los cuales cuatro tuvieron actividad antioxidante. Usando métodos espectroscópicos se identificaron a-tocoferol y tres flavonas metoxiladas. Con este estudio se confirmó que la fracción no volátil del aceite esencial de naranja contiene antioxidantes naturales diferentes al a-tocoferol.[EN] There has been a growing interest in the food industry and in preventive medicine to search for «natural antioxidants». Therefore the objetive of this study was to evaluate the antioxidant activity of the non-volatile residue of essential orange oil in the oxidation of unrefined and freshly extracted olive oil. Essential orange oil was distilled to obtain a non-volatile residue and fracctionated on a Silica Gel 60 column. The antioxidant activity was determined by measuring peroxide value obtained after heating olive oil at 70 °C for 48 h. Six compounds were isolated and purified, four of these had antioxidant activity, a-tocopherol and three methoxylated flavones were identified using spectroscopic methods. This study confirmed that non-volatile fractions of essential orange oil contain natural antioxidants diferent from a-tocopherol.Peer reviewe

Effect of organic and mineral fertilizers on greenhouse gases emissions from an irrigated maize crop in Madrid Spain

Both solid or liquid OF showed a significant abatement of N2O cumulative emissions in this irrigated Mediterranean cropping area (P < 0.05) comparing to U. Urea-Pig Compost (U-PC) treatment showed the lowest CH4 sink and highest cumulative soil respiration rates (P<05). Considering GHG-GWP, the use of OF can be considered as an advisable practice to mitigate GHG emissions under Mediterranean climatic conditions

Constitución del grupo de modelización de sistemas agrícolas españoles de REMEDIA (ReMSAE)

3 Pags.- Fots.- Figs.A principios de este mes de Diciembre tuvo lugar en el Basque Centre for Climate Change (BC3, Bilbao) el primer taller de modelización de emisiones de gases de efecto invernadero (GEI) en agrosistemas españoles. Enmarcada dentro de la red REMEDIA, esta actividad contó con la participación de un grupo de modelizadores de distintos centros de investigación y universidades españoles (BC3, UPM, CSIC, UdL y CIFA) que presentaron su trabajo en este ámbito y elaboraron un plan de trabajo a seguir en el futuro inmediato.Peer reviewe

Development of Interactive Materials by Engineering Students Using the Descartes Applets.

In a degree course such as Forestry Engineering, the general teaching objectives consist of explaining and helping students to understand the principles of Mechanics. For some time now we have encountered significant difficulties in teaching this subject due to the students' lack of motivation and to their insufficient prior preparation for the topic. If we add to this the discipline's inherent complexity and the students' preconceptions about the subject, these teaching difficulties become considerable. For this reason a series of didactic activities have been introduced sequentially in the teaching of this subject. This work describes the methodology, procedure and results for the action of developing a work project in groups using Descartes software. The results of this experiment can be considered very positive. Some of the critical preconceptions for learning the subject can be corrected, and the tutoring process in the classroom contributes to an improvement in teacherstudent communication. Since this scheme was established, the number of students taking part each academic year has increased, and this is the group with the greatest percentage of passing scores

Modeling GHG emissions, N and C dynamics in Spanish agricultural soils.

To date, only few initiatives have been carried out in Spain in order to use mathematical models (e.g. DNDC, DayCent, FASSET y SIMSNIC) to estimate nitrogen (N) and carbon (C) dynamics as well as greenhouse gases (GHG) in Spanish agrosystems. Modeling at this level may allow to gain insight on both the complex relationships between biological and physicochemical processes, controlling the processes leading to GHG production and consumption in soils (e.g. nitrification, denitrification, decomposing, etc.), and the interactions between C and N cycles within the different components of the continuum plant-soil-environment. Additionally, these models can simulate the processes behind production, consumition and transport of GHG (e.g. nitrous oxide, N2O, and carbon dioxide, CO2) in the short and medium term and at different scales. Other sources of potential pollution from soils can be identified and quantified using these process-based models (e.g. NO3 y NH3)

El papel de las micorrizas en la agricultura.

Las micorrizas son hongos simbióticos que colonizan las raíces de más de un 80% de las especies vegetales. Su presencia, entre otros factores, favorece un aumento de la absorción de nitrógeno y fósforo, reduce el estrés salino y el hídrico y aumenta la resistencia a determinados patógenos de sus plantas huésped. Son capaces también de incrementar el establecimiento, nodulación y capacidad de fijación de nitrógeno de las leguminosas. Es decir, pueden aumentar los rendimientos de los cultivos en los que se hallan. Su efecto sobre los gases de efecto invernadero es variable debido a los múltiples procesos en los que intervienen. Por lo tanto, el estudio de su ecología y funcionamiento en los ecosistemas agrarios es esencial para la mejora del crecimiento y productividad de los cultivos

Revision of the risk of secondary leukaemia after mitoxantrone in multiple sclerosis populations is required

The objective in this paper is to compare the cumulative incidence and incidence density of therapy-related acute myeloid leukaemia in two cohorts of patients with multiple sclerosis treated with mitoxantrone, and with previously reported data in the literature. Six new cases of acute myeloid leukaemia were observed by prospectively following two Spanish series of 142 and 88 patients with worsening relapsing multiple sclerosis and secondary-progressive disease treated with mitoxantrone. A literature review shows 32 further cases of acute myeloid leukaemia reported, 65.6% of which are therapy-related acute promyelocytic leukaemia. Five cases in the cohorts fulfilled the diagnostic criteria for acute promyelocytic leukaemia, and one patient was diagnosed with pre-B-acute lymphoblastic leukaemia. Acute myeloid leukaemia latency after mitoxantrone discontinuation was 1 to 45 months. The accumulated incidence and incidence density was 2.82% and 0.62%, respectively, in the Valencian cohort, and 2.27% and 0.44% in the Catalonian cohort. In the only seven previously reported series, the accumulated incidence varied from 0.15% to 0.80%. The real incidence of acute myeloid leukaemia after mitoxantrone therapy in the multiple sclerosis population could be higher as evidenced by the growing number of cases reported. Haematological monitoring should continue for at least 5 years after the last dose of mitoxantrone. These data stress the necessity of re-evaluating this ris