347 research outputs found

    Contribution of Collaborative Work to Teacher Reflection and the Transformation of Pedagogical Practices of School and University Science Teachers // Contribución del trabajo colaborativo en la reflexión docente y en la transformación de las prácticas pedagógicas de profesores de ciencia escolares y universitarios

    Get PDF
    Poor results of science learning, both at school and university, have led us to acknowledge the need to transform our teaching. Currently, reflection and collaborative work with colleagues are conceived as being key factors in the process of the transformation of practices. Based on the experiences of a group of school and university science teachers working on action-research, we describe the contribution that collaborative work has on reflection for the transformation of practices. The main aspects are the recognition of strengths and weaknesses, listening to and learning from the experience of others, and the discussion of specific classroom practices. On the other hand, these reflections contribute to the transformation at different levels: the teacher, classroom teaching practices, and the school community. The fact that it is a diverse group that includes both school and university teachers generate enriching reflections that help to transform practices in both areas. These reflections not only benefit the school system, but also science teachers education, and provide insights on a new University-School relationship // Los deficientes resultados de aprendizaje en el área de las ciencias, tanto en el ámbito escolar como universitario, nos han llevado a la necesidad de transformar nuestra enseñanza. En la actualidad, la reflexión y el trabajo colaborativo con colegas se conciben como claves en el proceso de transformación de las prácticas. A partir de la experiencia de un grupo de docentes escolares y universitarios de ciencia que realiza una investigación-acción, describimos la contribución que tiene el trabajo colaborativo sobre la reflexión para la transformación de las prácticas. Destacan aspectos como el reconocimiento de debilidades y fortalezas, el escuchar y aprender de la experiencia de otros y la discusión de prácticas concretas de aula. Por otra parte, estas reflexiones contribuyen a la transformación en diferentes niveles: del profesor, de las prácticas del docente en el aula y de la comunidad escolar. El hecho de que sea un grupo diverso, que incluye a profesores tanto del sistema escolar como universitario, genera reflexiones enriquecedoras, que ayudan a transformar las prácticas en estos dos ámbitos, beneficiando no solo al sistema escolar, sino también a la formación de profesores de ciencia, y dando luces acerca de una nueva relación universidad-escuela

    Principios de Desarrollo Profesional Docente construidos por y para Profesores de Ciencia: una propuesta sustentable que emerge desde la indagación de las propias prácticas / Principles of Teacher Professional Development built by and for Science Teachers: a sustainable proposal that emerges from the inquiry of self-practices

    Get PDF
    La transformación de las prácticas de los docentes en el área de ciencias, tanto a nivel escolar como universitario (incluida la formación inicial), constituye una necesidad urgente si pretendemos alfabetizar científicamente a la población. Este estudio muestra una propuesta de cinco principios para el desarrollo profesional docente en ciencias, que emergen desde la indagación colaborativa de las propias prácticas de un conjunto de docentes de educación primaria, secundaria y universitaria, quienes trabajan hace cuatro años en un proceso de desarrollo profesional conjunto. Estos principios incluyen la construcción de una visión común acerca del para qué enseñar ciencias, la indagación de las prácticas a partir de las particularidades de la educación científica, la reflexión individual y colectiva sobre las prácticas, la valoración de la autoridad de la experiencia para el aprendizaje docente y la promoción de un ambiente de desarrollo profesional que involucre diversidad de contextos y niveles de enseñanza. // The transformation of teaching practices in the area of sciences, both at school and university levels (including initial training), is an urgent need if we intend to achieve scientific literacy in the population. This study shows a proposal of five principles for teacher professional development in sciences, emerged from the collaborative inquiry of self-practices in a group of primary, secondary and university teachers, who have been working together for four years in a professional development process. These principles include the construction of a common vision on the purpose for teaching sciences; the inquiry of practices starting from the distinctive features of scientific education; individual and collective reflection on practices; the valuation of the authority of experience for teacher learning; and the promotion of an environment of professional development involving diverse contexts and teaching levels. Implications for professional development are discussed

    In vivo measurement of bending stiffness in fracture healing

    Get PDF
    BACKGROUND: Measurement of the bending stiffness a healing fracture represents a valid variable in the assessment of fracture healing. However, currently available methods typically have high measurement errors, even for mild pin loosening. Furthermore, these methods cannot provide actual values of bending stiffness, which precludes comparisons among individual fractures. Thus, even today, little information is available with regards to the fracture healing pattern with respect to actual values of bending stiffness. Our goals were, therefore: to develop a measurement device that would allow accurate and sensitive measurement of bending stiffness, even in the presence of mild pin loosening; to describe the course of healing in individual fractures; and help to evaluate whether the individual pattern of bending stiffness can be predicted at an early stage of healing. METHODS: A new measurement device has been developed to precisely measure the bending stiffness of the healing fracture by simulating four-point-bending. The system was calibrated on aluminum models and intact tibiae. The influence of pin loosening on measurement error was evaluated. The system was tested at weekly intervals in an animal experiment to determine the actual bending stiffness of the fracture. Transverse fractures were created in the right tibia of twelve sheep, and then stabilized with an external fixator. At ten weeks, bending stiffness of the tibiae were determined in a four-point-bending test device to validate the in-vivo-measurement data. RESULTS: In-vivo bending stiffness can be measured accurately and sensitive, even in the early phase of callus healing. Up to a bending stiffness of 10 Nm/degree, measurement error was below 3.4% for one pin loose, and below 29.3% for four pins loose, respectively. Measurement of stiffness data over time revealed a significant logarithmic increase between the third and seventh weeks, whereby the logarithmic rate of change among sheep was similar, but started from different levels. Comparative measurements showed that early individual changes between the third and fourth weeks can be used as a predictor of bending stiffness at seven weeks (r = 0.928) and at ten weeks (r = 0.710). CONCLUSION: Bending stiffness can be measured precisely, with less error in the case of pin loosening. Prediction of the future healing course of the individual fracture can be assessed by changes from the third to the fourth week, with differences in stiffness levels. Therefore, the initial status of the fracture seems to have a high impact on the individual healing course

    National smokefree law in New Zealand improves air quality inside bars, pubs and restaurants

    Get PDF
    <p>Abstract</p> <p>Background:</p> <p>We aimed to: (i) assess compliance with a new smokefree law in a range of hospitality settings; and (ii) to assess the impact of the new law by measuring air quality and making comparisons with air quality in outdoor smoking areas and with international data from hospitality settings.</p> <p>Methods:</p> <p>We included 34 pubs, restaurants and bars, 10 transportation settings, nine other indoor settings, six outdoor smoking areas of bars and restaurants, and six other outdoor settings. These were selected using a mix of random, convenience and purposeful sampling. The number of lit cigarettes among occupants at defined time points in each venue was observed and a portable real-time aerosol monitor was used to measure fine particulate levels (PM<sub>2.5</sub>).</p> <p>Results:</p> <p>No smoking was observed during the data collection periods among over 3785 people present in the indoor venues, nor in any of the transportation settings. The levels of fine particulates were relatively low inside the bars, pubs and restaurants in the urban and rural settings (mean 30-minute level = 16 μg/m<sup>3 </sup>for 34 venues; range of mean levels for each category: 13 μg/m<sup>3 </sup>to 22 μg/m<sup>3</sup>). The results for other smokefree indoor settings (shops, offices etc) and for smokefree transportation settings (eg, buses, trains, etc) were even lower. However, some "outdoor" smoking areas attached to bars/restaurants had high levels of fine particulates, especially those that were partly enclosed (eg, up to a 30-minute mean value of 182 μg/m<sup>3 </sup>and a peak of maximum value of 284 μg/m<sup>3</sup>). The latter are far above WHO guideline levels for 24-hour exposure (ie, 25μg/m<sup>3</sup>).</p> <p>Conclusion:</p> <p>There was very high compliance with the new national smokefree law and this was also reflected by the relatively good indoor air quality in hospitality settings (compared to the "outdoor" smoking areas and the comparable settings in countries that permit indoor smoking). Nevertheless, adopting enhanced regulations (as used in various US and Canadian jurisdictions) may be needed to address hazardous air quality in relatively enclosed "outdoor" smoking areas.</p

    Multiple Wnts Redundantly Control Polarity Orientation in Caenorhabditis elegans Epithelial Stem Cells

    Get PDF
    During development, cell polarization is often coordinated to harmonize tissue patterning and morphogenesis. However, how extrinsic signals synchronize cell polarization is not understood. In Caenorhabditis elegans, most mitotic cells are polarized along the anterior-posterior axis and divide asymmetrically. Although this process is regulated by a Wnt-signaling pathway, Wnts functioning in cell polarity have been demonstrated in only a few cells. We analyzed how Wnts control cell polarity, using compound Wnt mutants, including animals with mutations in all five Wnt genes. We found that somatic gonadal precursor cells (SGPs) are properly polarized and oriented in quintuple Wnt mutants, suggesting Wnts are dispensable for the SGPs' polarity, which instead requires signals from the germ cells. Thus, signals from the germ cells organize the C. elegans somatic gonad. In contrast, in compound but not single Wnt mutants, most of the six seam cells, V1–V6 (which are epithelial stem cells), retain their polarization, but their polar orientation becomes random, indicating that it is redundantly regulated by multiple Wnt genes. In contrast, in animals in which the functions of three Wnt receptors (LIN-17, MOM-5, and CAM-1) are disrupted—the stem cells are not polarized and divide symmetrically—suggesting that the Wnt receptors are essential for generating polarity and that they function even in the absence of Wnts. All the seam cells except V5 were polarized properly by a single Wnt gene expressed at the cell's anterior or posterior. The ectopic expression of posteriorly expressed Wnts in an anterior region and vice versa rescued polarity defects in compound Wnt mutants, raising two possibilities: one, Wnts permissively control the orientation of polarity; or two, Wnt functions are instructive, but which orientation they specify is determined by the cells that express them. Our results provide a paradigm for understanding how cell polarity is coordinated by extrinsic signals

    Photosynthesis-dependent H₂O₂ transfer from chloroplasts to nuclei provides a high-light signalling mechanism

    Get PDF
    Chloroplasts communicate information by signalling to nuclei during acclimation to fluctuating light. Several potential operating signals originating from chloroplasts have been proposed, but none have been shown to move to nuclei to modulate gene expression. One proposed signal is hydrogen peroxide (H2O2) produced by chloroplasts in a light-dependent manner. Using HyPer2, a genetically encoded fluorescent H2O2 sensor, we show that in photosynthetic Nicotiana benthamiana epidermal cells, exposure to high light increases H2O2 production in chloroplast stroma, cytosol and nuclei. Critically, over-expression of stromal ascorbate peroxidase (H2O2 scavenger) or treatment with DCMU (photosynthesis inhibitor) attenuates nuclear H2O2 accumulation and high light-responsive gene expression. Cytosolic ascorbate peroxidase over-expression has little effect on nuclear H2O2 accumulation and high light-responsive gene expression. This is because the H2O2 derives from a sub-population of chloroplasts closely associated with nuclei. Therefore, direct H2O2 transfer from chloroplasts to nuclei, avoiding the cytosol, enables photosynthetic control over gene expression
    corecore