99 research outputs found
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
LEPTS – a Radiation-Matter Interaction Model at the Molecular Level and its Use in Biomedical Applications
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
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