5,167 research outputs found

    Modelling the economics of agroforestry at field- and farm-scale

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    This report (Deliverable 6.18) assesses the economics of agroforestry systems at field- and farm-scales and compares them with alternative land uses such as arable cropping, pasture and forestry. This analysis is undertaken in terms of financial profitability (e.g. from a farmer perspective) and economic benefits (e.g. from a societal perspective)N/

    On the benefits of tasking with OpenMP

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    Tasking promises a model to program parallel applications that provides intuitive semantics. In the case of tasks with dependences, it also promises better load balancing by removing global synchronizations (barriers), and potential for improved locality. Still, the adoption of tasking in production HPC codes has been slow. Despite OpenMP supporting tasks, most codes rely on worksharing-loop constructs alongside MPI primitives. This paper provides insights on the benefits of tasking over the worksharing-loop model by reporting on the experience of taskifying an adaptive mesh refinement proxy application: miniAMR. The performance evaluation shows the taskified implementation being 15–30% faster than the loop-parallel one for certain thread counts across four systems, three architectures and four compilers thanks to better load balancing and system utilization. Dynamic scheduling of loops narrows the gap but still falls short of tasking due to serial sections between loops. Locality improvements are incidental due to the lack of locality-aware scheduling. Overall, the introduction of asynchrony with tasking lives up to its promises, provided that programmers parallelize beyond individual loops and across application phases.Peer ReviewedPostprint (author's final draft

    ¿Es realmente fiable la evaluación no individualizada en el trabajo cooperativo?

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    Se presentan y discuten los resultados de una experiencia de trabajo cooperativo empleando la plataforma BSCW en alumnos de la titulación de Maestro de Educación Infantil de la Universidad de Barcelona, con el fin de detectar posibles sesgos de las coevaluaciones y las autoevaluaciones, y para valorar la incidencia que tienen los comportamientos disruptivos en el proceso cooperativo de evaluación. Los resultados muestran que el alumnado es honesto en las calificaciones que otorga, y que los comportamientos disruptivos detectados en los distintos grupos de trabajo cooperativo, causados por una baja ciudadanía de equipo, no tienen una incidencia significativa en las calificaciones otorgadas por el grupo clase. Por tanto, se legitiman las coevaluaciones y las autoevaluaciones como instrumentos fiables de evaluación en un contexto de trabajo cooperativo

    Does posterior capsule opacification affect the results of diagnostic technologies to evaluate the retina and the optic disc?

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    The visual outcome obtained after cataract removal may progressively decline because of posterior capsular opacification (PCO). This condition can be treated by creating an opening in the posterior lens capsule by Nd:YAG laser capsulotomy. PCO optical imperfections cause several light reflection, refraction, and diffraction phenomena, which may interfere with the functional and structural tests performed in different ocular locations for the diagnosis and follow-up of ocular disease, like macular and optic nerve diseases. Some parameters measured by visual field examinations, scanning laser polarimetry, and optical coherence tomography (OCT) have changed after PCO removal. Imaging quality also changes following capsulotomy. Consequently, the results of ancillary tests in pseudophakic eyes for studying ocular diseases like glaucoma or maculopathies should be correlated with other clinical examinations, for example, slit-lamp biomicroscopy or funduscopy. If PCO is clinically significant, a new baseline should be set for future comparisons following capsulotomy when using automated perimetry and scanning laser polarimetry. To perform OCT in the presence of PCO, reliable examinations (considering signal strength) apparently guarantee that measurements are not influenced by PCO

    Generation of membrane-bound catechol-O-methyl transferase deficient mice with disctinct sex dependent behavioral phenotype.

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    PMID: 28195063Catechol-O-methyltransferase (COMT) has two isoforms: soluble (S-COMT), which resides in the cytoplasm, and membrane-bound (MB-MT), anchored to intracellular membranes. COMT is involved in the O-methylation of L-DOPA, dopamine and other catechols. The exact role of MB-COMT is still mostly unclear. We wanted to create a novel genetically modified mouse model that specifically lacks MB-COMT activity and to study their behavioral phenotype. MB-COMT knock-in mutant mice were generated by introducing two point mutations in exon 2 of the Comt gene (ATGCTG->GAGCTC disabling the function of the P2 promoter and allowing only the P1-regulated S-COMT transcription. The first mutation changes methionine to glutamic acid whereas the second one does not affect coding. The expression of the two COMT isoforms, total COMT activity in several areas of the brain and peripheral tissues and extracellular dopamine concentrations after L-DOPA (10 mg/kg) and carbidopa (30 mg/kg) subcutaneous administration were assessed. A battery of behavioral tests was performed to compare MB-COMT deficient mice and their wild type littermates of both sexes. MB-COMT deficient mice were seemingly normal, bred usually and had unaltered COMT activity in the brain and periphery despite a complete lack of the MB-COMT protein. MB-COMT deficient male mice showed higher extracellular dopamine levels than their wild-type littermates in the striatum, but not in the mPFC. In addition, the MB-COMT deficient male mice exhibited a distinct endophenotype characterized by schizophrenia-related behaviors like aggressive behavior and reduced prepulse inhibition. They also had prolonged immobility in the tail suspension test. Both sexes were sensitized to acute pain and had normal motor activity but disturbed short-term memory. Hence the behavioral phenotype was not limited to schizophrenia-related endophenotype and some behavioural findings were not sex-dependent. Our findings indicate that MB-COMT is critical for behavior, and its function in COMT-dependent brain areas cannot be entirely substituted by the remaining S-COMT.Peer reviewe

    Hepatic metastases from colorectal cancer: preoperative detectiona and assessment of resectability with helical CT

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    Purpose: to prospectively evaluate helical computed tomography (CT) in the preoperative detection of hepatic metastases and assessment of resectability with surgical, intraoperative ultrasonographic (US), and histopathologic correlation. Materials and methods: between October 1995 and December 1998, preoperative staging with helical CT (5-mm collimation; reconstruction interval, 5 mm) was performed in 157 patients with hepatic metastases. Iodinated contrast material was injected intravenously (160-170 mL; rate, 2.5-3.0 mL/sec); acquisition began at 60-70 seconds. Four radiologists prospectively assessed the metastatic involvement of the liver by indicating the number and location of the lesions; resection was indicated in 113 patients (119 instances). Helical CT findings were correlated with pathologic and surgical findings on a lesion-by-lesion basis. Results: intraoperative US, palpation, and histopathologic examination revealed 290 liver metastases; helical CT correctly depicted 247. Helical CT results were the following: overall detection rate, 85.1% (95% CI: 80.8%, 89.3%); positive predictive value, 96.1% (95% CI: 92.9%, 98.1%); and false-positive rate, 3.9% (10 of 257 findings; 95% CI: 1.9%, 7.1%). False-positive findings were related to hemangioendothelioma, hemangioma, hepatic peliosis, biliary adenoma, centrilobar hemorrhage, biliary hamartoma, periportal fibrosis, and normal liver parenchyma. Curative resection was performed in 112 instances with a resectability rate of 94.1%. Four-year patient survival rate was 58.6%. Conclusion: helical CT is a noninvasive, reliable, and accurate technique for imaging the liver and should be considered as the standard preoperative work-up of hepatic metastases from colorectal cancer
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