188 research outputs found

    An evaluation of the Behavior and Instructional Management Scale's psychometric properties using portuguese teachers

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    Classroom management research is an important topic as teachers cannot effectively educate students in unstructured environments. With that said, few psychometrically sound measures are available to measure behavior and instructional management. Using 1520 Portuguese teachers, we evaluated the Behavior and Instructional Management Scale's (BIMS) psychometric properties using Bayesian estimation and found that the original 12-item scale provided reasonable evidence of factorial validity and internal consistency reliability; however, a slightly revised model may be more promising. The BIMS subscales also had strong concurrent validity evidence based on the associations with perceived student engagement, perceived instructional strategies, and perceived classroom management

    Teacher’s classroom management behavior and students’ classroom misbehavior: A study with 5th through 9th-grade students

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    Introduction. Classroom misbehavior is a major source of classroom-wasted time and a situation that negatively interferes with students’ opportunity to learn. Method. The present study investigated the relation between 5th through 9th grade perceived Portuguese teacher’s classroom management, teacher’s perceived time spend with misbehavior, teacher’s self-efficacy, and teacher’s perceived classroom misbehavior. A conditional process analysis of the relation between teacher’s classroom management and teacher’s perceived classroom misbehavior with mediator and moderator variables was tested. Results. Generically the results show that (1) teachers who perceive themselves as more controllers of students’ behaviors tend to perceive less misbehavior in the classroom; (2) that both teacher’s self-efficacy efficacy (TSE) and time spent with classroom misbehavior (TSMisb) are better predictors of classroom misbehavior than the classroom behavior management style; (3) both TSE and TSMisb fully mediate the relation between classroom management style and classroom perceived misbehavior. Discussion and Conclusion. Teachers must, therefore, learn the specific behaviors that more likely optimize the available instructional time and reduce time and energy wasted with students’ misbehavior.Introducción. Los problemas de comportamiento constituyen una de las más grandes fuentes de pérdida de tiempo en el aula y afectan negativamente las oportunidades de aprendizaje de los alumnos. Método. Participaron en este estudio 600 profesores de los segundo y tercer ciclos del sistema educativo portugués (5º a 9º cursos). Se estudio la relación entre las percepciones de los profesores sobre su estilo de gestión de clase, el tiempo usado con conductas disruptivas, la autoeficacia docente y la disciplina en el aula. Resultados. Genéricamente los resultados muestran que: (1) los profesores que se perciben como más controladores de las conductas de los alumnos tienden a percibir menos problemas de comportamiento en el aula; (2) que la autoeficacia de los profesores y el tiempo gastado con conductas disruptivas en el aula son mejores predictores de la indisciplina que el estilo de gestión de clase; (3) la autoeficacia e el tiempo perdido con conductas disruptivas median totalmente la relación entre el estilo de gestión del aula y la indisciplina percibida. Discusión y Conclusión. Los profesores deben conocer los comportamientos específicos que más probablemente optimizan el tiempo de instrucción disponible y reducen el tiempo y la energía desperdiciados con la indisciplina en el aula.info:eu-repo/semantics/publishedVersio

    Comprehensive analysis of temporal alterations in cellular proteome of bacillus subtilis under curcumin treatment

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    Curcumin is a natural dietary compound with antimicrobial activity against various gram positive and negative bacteria. This study aims to investigate the proteome level alterations in Bacillus subtilis due to curcumin treatment and identification of its molecular/cellular targets to understand the mechanism of action. We have performed a comprehensive proteomic analysis of B. subtilis AH75 strain at different time intervals of curcumin treatment (20, 60 and 120 min after the drug exposure, three replicates) to compare the protein expression profiles using two complementary quantitative proteomic techniques, 2D-DIGE and iTRAQ. To the best of our knowledge, this is the first comprehensive longitudinal investigation describing the effect of curcumin treatment on B. subtilis proteome. The proteomics analysis revealed several interesting targets such UDP-N-acetylglucosamine 1-carboxyvinyltransferase 1, putative septation protein SpoVG and ATP-dependent Clp protease proteolytic subunit. Further, in silico pathway analysis using DAVID and KOBAS has revealed modulation of pathways related to the fatty acid metabolism and cell wall synthesis, which are crucial for cell viability. Our findings revealed that curcumin treatment lead to inhibition of the cell wall and fatty acid synthesis in addition to differential expression of many crucial proteins involved in modulation of bacterial metabolism. Findings obtained from proteomics analysis were further validated using 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) assay for respiratory activity, resazurin assay for metabolic activity and membrane integrity assay by potassium and inorganic phosphate leakage measurement. The gene expression analysis of selected cell wall biosynthesis enzymes has strengthened the proteomics findings and indicated the major effect of curcumin on cell division

    Is there a common water-activity limit for the three domains of life?

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    Archaea and Bacteria constitute a majority of life systems on Earth but have long been considered inferior to Eukarya in terms of solute tolerance. Whereas the most halophilic prokaryotes are known for an ability to multiply at saturated NaCl (water activity (a w) 0.755) some xerophilic fungi can germinate, usually at high-sugar concentrations, at values as low as 0.650-0.605 a w. Here, we present evidence that halophilic prokayotes can grow down to water activities of <0.755 for Halanaerobium lacusrosei (0.748), Halobacterium strain 004.1 (0.728), Halobacterium sp. NRC-1 and Halococcus morrhuae (0.717), Haloquadratum walsbyi (0.709), Halococcus salifodinae (0.693), Halobacterium noricense (0.687), Natrinema pallidum (0.681) and haloarchaeal strains GN-2 and GN-5 (0.635 a w). Furthermore, extrapolation of growth curves (prone to giving conservative estimates) indicated theoretical minima down to 0.611 a w for extreme, obligately halophilic Archaea and Bacteria. These were compared with minima for the most solute-tolerant Bacteria in high-sugar (or other non-saline) media (Mycobacterium spp., Tetragenococcus halophilus, Saccharibacter floricola, Staphylococcus aureus and so on) and eukaryotic microbes in saline (Wallemia spp., Basipetospora halophila, Dunaliella spp. and so on) and high-sugar substrates (for example, Xeromyces bisporus, Zygosaccharomyces rouxii, Aspergillus and Eurotium spp.). We also manipulated the balance of chaotropic and kosmotropic stressors for the extreme, xerophilic fungi Aspergillus penicilloides and X. bisporus and, via this approach, their established water-activity limits for mycelial growth (∼0.65) were reduced to 0.640. Furthermore, extrapolations indicated theoretical limits of 0.632 and 0.636 a w for A. penicilloides and X. bisporus, respectively. Collectively, these findings suggest that there is a common water-activity limit that is determined by physicochemical constraints for the three domains of life

    Deciduous Trees and the Application of Universal DNA Barcodes: A Case Study on the Circumpolar Fraxinus

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    The utility of DNA barcoding for identifying representative specimens of the circumpolar tree genus Fraxinus (56 species) was investigated. We examined the genetic variability of several loci suggested in chloroplast DNA barcode protocols such as matK, rpoB, rpoC1 and trnH-psbA in a large worldwide sample of Fraxinus species. The chloroplast intergenic spacer rpl32-trnL was further assessed in search for a potentially variable and useful locus. The results of the study suggest that the proposed cpDNA loci, alone or in combination, cannot fully discriminate among species because of the generally low rates of substitution in the chloroplast genome of Fraxinus. The intergenic spacer trnH-psbA was the best performing locus, but genetic distance-based discrimination was moderately successful and only resulted in the separation of the samples at the subgenus level. Use of the BLAST approach was better than the neighbor-joining tree reconstruction method with pairwise Kimura's two-parameter rates of substitution, but allowed for the correct identification of only less than half of the species sampled. Such rates are substantially lower than the success rate required for a standardised barcoding approach. Consequently, the current cpDNA barcodes are inadequate to fully discriminate Fraxinus species. Given that a low rate of substitution is common among the plastid genomes of trees, the use of the plant cpDNA “universal” barcode may not be suitable for the safe identification of tree species below a generic or sectional level. Supplementary barcoding loci of the nuclear genome and alternative solutions are proposed and discussed
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