382 research outputs found
University Teachers’ Conceptions of the University and the Place of Sustainability
In this phenomenographic qualitative research, the aim is to learn about the conceptions of university professors about the university. The study was carried out with 20 university professors: 10 from the School of Social Sciences and 10 from the School of Science and Technology of University of Évora with an average age of 54 years and over 20 years of professional activity. The data were collected through open questionnaires and then submitted to thematic and categorical content analysis. The conceptions of the university appear, in the voice of the teachers, centered on two main aspects. The first and more mentioned concerns the conception of the university as a space of production and diffusion of scientific knowledge, which refers to quality factors of higher education. The second brings out the conception of the university as a space of relationship with society together with underlying concerns for human development, cooperation, and the design of a more sustainable world
Física en la enseñanza secundaria : qué trabajo experimental?
En las dos últimas décadas, han surgido diversas propuestas enfocadas a mejorar la contribución del TE en el aprendizaje de los alumnos, y sugieren, que éste tenga un carácter de actividad de resolución de problemas, donde el alumno desempeñe un papel central tanto en la planificación como en la ejecución ejecución Los resultados presentados se basen en una investigación con alumnos de Física y Química de la Enseñanza Secundaria de dos escuelas portuguesas. Se hace una comparación entre las características del TE implementado en las aulas de estos alumnos y las características de TE que, en su opinión, favorecerían el aprendizaje
Antibacterial activity of crude methanolic extract and fractions obtained from Larrea tridentata leaves
Larrea tridentata (Zygophyllaceae), commonly known as creosote bush, is a plant that grows in semiarid areas of Southwestern United States and Northern Mexico and was traditionally used for medicinal purposes. This plantis a notable source of natural compounds with approximately 50% of the leaves (dry weight) being extractable matter. This study was designed to evaluate the antibacterial activity of the crude methanolic extract (CME) and fractions [hexane (H), dicloromethane (DCM), ethyl acetate (EA) and ethanol (Et)] obtained from Larrea tridentata leaves. A preliminary study of the antibacterial activity was performed using the agar diffusion method against six strains of Gram-positive and Gram-negative bacteria. The micro-dilution method was applied for the determination of the minimal inhibitory concentration (MIC) of selected bacteria strains. HPLC analyses of tested samples were also carried out. The antibacterial activity of the tested samples was noticeable more effective inhibiting the growth of Gram-positive bacteria comparing with Gram-negative bacteria, by the CME, DCM and EA fractions. EA fraction showed the highest antibacterial activity against methicillin-resistant Staphylococcus aureus isolated from secretion; with a MIC value (31.3 μg/mL) lower than the reference antibiotic tetracycline (64 μg/mL). Low MIC values (62.5 μg/mL) were also obtained for crude methanolic extract and DCM fraction compared to tetracycline. The highest concentrations of quercetin, kaempferol and nordihydroguaiaretic acid were observed in CME (8.67, 21.52 and 35.75 mg/g, respectively); nevertheless, EA fraction also showed considerable levels of these compounds compared with the remaining fractions. Other compounds were observed in the HPLC chromatograms and further studies are needed in order to identify them. The antibacterial activity of the samples studied might be explained by the synergistic or additive effects of several components rather than arising from a single compound. In conclusion, EA fraction showed the most promising results against the bacterial strain methicillin-resistant Staphylococcus aureus, which represents an important step for the search and development of a new antibacterial agent. Nevertheless, further toxicological and pharmacological studies are needed in order to confirm the hypothesis of using phytochemicals from Larrea tridentata leaves
Schizodeme analysis with the restriction endonuclease RSA I differentiates between Trypanosoma rangeli and Trypanosoma cruzi
Scalable Task Cleanup Assignment for Multi-agents
This paper describes a group of robots for cleaning a simulated environment and proposes an ecient algorithm for navigation based on Path nding A *. No need for vision sensors. As a result it was observed that the robots can work cooperatively to clear the ground and that the navigation algorithm is e ective in cleaning. In order to test its eciency it was compared the combination of the Path nding A* algorithm and the decision algorithm proposed in this paper with Path nding A* and Euclidean distance, resulted in an improvement in time and distance traveled
Trans
This study investigated the leishmanicidal activity against Leishmania amazonensis of four commercial oils from Copaifera spp. named as C1, C2, C3, and C4, the sesquiterpene and diterpene pools obtained from distilling C4, and isolated β-caryophyllene (CAR). Copaiba oils chemical compositions were analyzed by gas chromatography and correlated with biological activities. Diterpenes-rich oils C2 and C3 showed antipromastigote activity. Sesquiterpenes-rich C1 and C4, and isolated CAR presented a dose-dependent activity against intracellular amastigotes, with IC50s of 2.9 µg/mL, 2.3 µg/mL, and 1.3 µg/mL (6.4 µM), respectively. Based on the highest antiamastigote activity and the low toxicity to the host cells, C4 was steamdistillated to separate pools of sesquiterpenes and diterpenes. Both pools were less active against L. amazonensis and more toxic for the macrophages than the whole C4 oil. The leishmanicidal activity of C3 and C4 oils, as well as C4 fractions and CAR, appears to be independent of nitric oxide production by macrophages. This study pointed out β-caryophyllene as an effective antileishmanial compound and also to its role as potential chemical marker in copaiba oils or fractions derived thereof, aiming further development of this rainforest raw material for leishmaniasis therapy
Development and application of a next-generation-sequencing (NGS) approach to detect known and novel gene defects underlying retinal diseases
<p>Abstract</p> <p>Background</p> <p>Inherited retinal disorders are clinically and genetically heterogeneous with more than 150 gene defects accounting for the diversity of disease phenotypes. So far, mutation detection was mainly performed by APEX technology and direct Sanger sequencing of known genes. However, these methods are time consuming, expensive and unable to provide a result if the patient carries a new gene mutation. In addition, multiplicity of phenotypes associated with the same gene defect may be overlooked.</p> <p>Methods</p> <p>To overcome these challenges, we designed an exon sequencing array to target 254 known and candidate genes using Agilent capture. Subsequently, 20 DNA samples from 17 different families, including four patients with known mutations were sequenced using Illumina Genome Analyzer IIx next-generation-sequencing (NGS) platform. Different filtering approaches were applied to identify the genetic defect. The most likely disease causing variants were analyzed by Sanger sequencing. Co-segregation and sequencing analysis of control samples validated the pathogenicity of the observed variants.</p> <p>Results</p> <p>The phenotype of the patients included retinitis pigmentosa, congenital stationary night blindness, Best disease, early-onset cone dystrophy and Stargardt disease. In three of four control samples with known genotypes NGS detected the expected mutations. Three known and five novel mutations were identified in <it>NR2E3, PRPF3, EYS, PRPF8, CRB1, TRPM1 </it>and <it>CACNA1F</it>. One of the control samples with a known genotype belongs to a family with two clinical phenotypes (Best and CSNB), where a novel mutation was identified for CSNB. In six families the disease associated mutations were not found, indicating that novel gene defects remain to be identified.</p> <p>Conclusions</p> <p>In summary, this unbiased and time-efficient NGS approach allowed mutation detection in 75% of control cases and in 57% of test cases. Furthermore, it has the possibility of associating known gene defects with novel phenotypes and mode of inheritance.</p
Navigation of quadruped multirobots by gesture recognition using restricted boltzmann machines
This article discusses a method that performs gesture recognition, with the objective of extracting characteristics of the segmented hand, from dynamic images captured from a webcam and identifying signal patterns. With this method it is possible to manipulate simulated multirobots that perform specific movements. The method consists of the Continuously Adaptive Mean-SHIFT algorithm, followed by the Threshold segmentation algorithm and Deep Learning through Boltzmann restricted machines. As a result, an accuracy of 82.2%
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