296 research outputs found

    Assessing impacts of Common Agricultural Policy changes on regional use patterns with a decision support system. An application in Southern Portugal

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    This paper discusses research aiming at assessing Common Agricultural Policy impacts on agriculture and forestry. For this purpose an approach is developed that includes a linear programming model to estimate the Positive Mathematical Programming production cost function coefficients of current agricultural– forestry activities. It further includes a heuristic — simulated annealing — to generate solutions for each policy scenario. This model base approach is integrated within a decision support system (DSS) for testing purposes. The DSS further encompasses a relational database that stores agricultural–forestry technical and economic data and a geographic information system that stores topological data of regional farm-type land units. The DSS Graphical User Interface provides tabular and geographical reporting capabilities. Results are discussed for an application to the Alentejo region in Southern Portugal. Results demonstrate the usefulness and relevance of the proposed approach to assess the impact of changes in prices and in agricultural policy on land use patterns and on forestr

    Evaluation of Nanoparticle Uptake iii Co-culture Cancer Modeis

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    Co-culture models are currently bridging the gap between classical cultures and in vivo animal models. Exploring this novel approach unlocks the possibility to mimic the tumor microenvironment in vitro, through the establishment of cancer-stroma synergistic interactions. Notably, these organotypic models offer a perfect platform for the development and pre-clinical evaluation of candidate nanocarriers loaded with anti-tumoral drugs in a high throughput screening mode, with lower costs and absence of ethical issues. However, this evaluation was until now limited to co-culture systems established with precise cell ratios, not addressing the natural cell heterogeneity commonly found in different tumors. Therefore, herein the multifunctional nanocarriers efficiency was characterized in various fibroblast-MCF-7 co-culture systems containing different cell ratios, in order to unravel key design parameters that influence nanocarrier performance and the therapeutic outcome. The successful establishment of the co-culture models was confirmed by the tissue-like distribution of the different cells in culture. Nanoparticles incubation in the various co-culture systems reveals that these nanocarriers possess targeting specificity for cancer cells, indicating their suitability for being used in this illness therapy. Additionally, by using different co-culture ratios, different nanoparticle uptake profiles were obtained. These findings are of crucial importance for the future design and optimization of new drug delivery systems, since their real targeting capacity must be addressed in heterogenous cell populations, such as those found in tumors.PEst-OE/EGEJUI4D5G/201

    Evaluacion de la probabilidad de ocurrencia de fuegos en rodales de Pinus pinaster Ait en Portugal

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    Maritime pine (Pinus pinaster Ait.) is an important conifer from the western Mediterranean Basin extending over 22% of the forest area in Portugal. In the last three decades nearly 4% of Maritime pine area has been burned by wildfires. Yet no wildfire occurrence probability models are available and forest and fire management planning activities are thus carried out mostly independently of each other. This paper presents research to address this gap. Specifically, it presents a model to assess wildfire occurrence probability in regular and pure Maritime pine stands in Portugal. Emphasis was in developing a model based on easily available inventory data so that it might be useful to forest managers. For that purpose, data from the last two Portuguese National Forest Inventories (NFI) and data from wildfire perimeters in the years from 1998 to 2004 and from 2006 to 2007 were used. A binary logistic regression model was build using biometric data from the NFL Biometric data included indicators that might be changed by operations prescribed in forest planning. Results showed that the probability of wildfire occurrence in a stand increases in stand located at steeper slopes and with high shrubs load while it decreases with precipitation and with stand basal area. These results are instrumental for assessing the impact of forest management options on wildfire probability thus helping forest managers to reduce the risk of wildfire

    Estudio de la activación neutrónica del acero inoxidable en un reactor nuclear

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    Durante la operación de un reactor nuclear, diferentes componentes pueden activarse por reacciones neutrónicas. La actividad así generada produce una dosis que es un riesgo potencial para los trabajadores del entorno. Se ha simulado mediante los códigos MCNP y CINDER’90 dicha activación en una pieza de acero y comparado los valores obtenidos con mediciones experimentales. Se verifica la equivalencia de ambos métodos para los cálculos de activación neutrónica y evolución de la tasa de dosis con el tiempo de enfriamiento.Lázaro Roche, I.; Ródenas Diago, J.; Marques, J. (2013). Estudio de la activación neutrónica del acero inoxidable en un reactor nuclear. Sociedad Nuclear Española. http://hdl.handle.net/10251/71624

    Nucleon-nucleon momentum correlation function for light nuclei

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    Nucleon-nucleon momentum correlation function have been presented for nuclear reactions with neutron-rich or proton-rich projectiles using a nuclear transport theory, namely Isospin-Dependent Quantum Molecular Dynamics model. The relationship between the binding energy of projectiles and the strength of proton-neutron correlation function at small relative momentum has been explored, while proton-proton correlation function shows its sensitivity to the proton density distribution. Those results show that nucleon-nucleon correlation function is useful to reflect some features of the neutron- or proton-halo nuclei and therefore provide a potential tool for the studies of radioactive beam physics.Comment: Talk given at the 18th International IUPAP Conference on Few-Body Problems in Physics (FB18), Santos, Brasil, August 21-26, 2006. To appear in Nucl. Phys.

    Evaluation of Chromane Derivatives: Promising Privileged Scaffolds for Lead Discovery within Alzheimer’s Disease

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    The chromane ring system is widely distributed in nature and has proven to be a highly potent pharmacophore in medicinal chemistry, which includes the area of Alzheimer’s and Parkinson’s diseases. We report on the development of a gem-dimethylchroman-4-ol family that was shown to give good inhibition of equine serum butyrylcholinesterase (eqBuChE) (in the range 2.9 – 7.3 μM) and in the same range of currently used drugs. We also synthesized a small library of gem-dimethylchroman-4-amine compounds, via a simple reductive amination of the corresponding chromanone precursor, that were also selective for eqBuChE presenting inhibitions in the range 7.6 – 67 μM. Kinetic studies revealed that they were mixed inhibitors. Insights into their mechanism of action were obtained through molecular docking and STD-NMR experiments, and the most active examples showed excellent drug-likeness and pharmacological properties predicted using Swiss-ADME. We also prepared a set of propargyl gem-dimethylchromanamines, for monoamine oxidase (MAO) inhibition but they were only moderately active (the best being 28% inhibition at 1 µM on MAO-B). Overall, our compounds were found to be best suited as inhibitors for BuChE

    DEBATENDO O FAZER DIDÁTICO: A PERCEPÇÃO DOS ESTUDANTES DE CIÊNCIAS CONTÁBEIS ACERCA DAS ESTRATÉGIAS DIDÁTICAS UTILIZADAS

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    O presente estudo buscou analisar a percepção dos estudantes sobre as estratégias didáticas utilizadas pelos seus professores. O estudo de natureza descritiva, do tipo survey e com abordagem quali-quantitativa analisou dados de 131 estudantes de Ciências Contábeis do 1º ao 8º período da maior universidade privada do país. As técnicas de análise de dados utilizadas foram a estatística descritiva à luz das teorias pedagógicas vigentes. Os resultados demonstraram que em geral os professores utilizam estratégias ativas e passivas (ambas) e que os alunos percebem essa combinação (58%) como mais proveitosa para o processo de ensino-aprendizagem. Dentre as contribuições das estratégias didáticas para o processo de ensino-aprendizagem destacaram-se: Resolução de exercícios (16%); Aula expositiva (15%); Discussão e debates (13%); Estudo de Caso (12%). Além disso, na perspectiva dos respondentes existe uma necessidade de maior comprometimento das partes (35,64%) e conexão com o mercado de trabalho (40,28%) para que o processo de ensino-aprendizagem melhore. 

    Assessing impacts of Common Agricultural Policy changes on regional land use

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    This paper discusses research aiming at assessing Common Agricultural Policy impacts on agriculture and forestry. For this purpose an approach is developed that includes a linear programming model to estimate the Positive Mathematical Programming production cost function coefficients of current agricultural– forestry activities. It further includes a heuristic — simulated annealing — to generate solutions for each policy scenario. This model base approach is integrated within a decision support system (DSS) for testing purposes. The DSS further encompasses a relational database that stores agricultural–forestry technical and economic data and a geographic information system that stores topological data of regional farm-type land units. The DSS Graphical User Interface provides tabular and geographical reporting capabilities. Results are discussed for an application to the Alentejo region in Southern Portugal. Results demonstrate the usefulness and relevance of the proposed approach to assess the impact of changes in prices and in agricultural policy on land use patterns and on forestry

    Acoustic instrumentation for a bubble chamber towards dark matter searches

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    Dark matter is one of the top unsolved mysteries in physics. Its existence is well-established although its nature remains unknown. Despite the progress made in the direct search effort, reflecting over 10 orders of magnitude in sensitivity since 1984, no true candidates to explain this phenomenon have appeared in searches covering a range from ~10 GeV to 1 TeV. This article reports on the development of a 1 kg freon bubble chamber prototype, including the chamber recompression system design and testing, initial acoustic detection of bubble formation, and initial neutron and alpha detector response studies. The prototype constructed was a transparent acrylic containment vessel, capable of withstanding recompression cycles to a pressure of 16 bar. The acoustic signal accompanying bubble formation was investigated using three different sensors: a low frequency microphone (Panasonic) with a flat response over 0.020-16 kHz, an ultrasound externallypolarized condenser microphone (AviSoft) with a flat response over 10-150 kHz, and an hydrophone (Reson) with a flat response over 5-170 kHz. Acoustic signatures of several induced events were successfully registered. The data acquisition digitizer used, to meet the range of the three microphones, was the NI PCI-6251 16-Bit, with at least 1.25 MSps for 1-Channel
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