On the harmonicity of normal almost contact metric structures

We consider normal almost contact structures on a Riemannian manifold and, through their associated sections of an ad-hoc twistor bundle, study their harmonicity, as sections or as maps. We rewrite these harmonicity equations in terms of the Riemann curvature tensor and find conditions relating the harmonicity of the almost contact and almost complex structures of the total and base spaces of the Morimoto fibration.Comment: 14 page

Practice-oriented controversies and borrowed epistemic credibility in current evolutionary biology: phylogeography as a case study

Although there is increasing recognition that theory and practice in science are intimately intertwined, philosophy of science perspectives on scientific controversies have been historically focused on theory rather than practice. As a step in the construction of frameworks for understanding controversies linked to scientific practices, here we introduce the notion of borrowed epistemic credibility (BEC), to describe the situation in which scientists, in order to garner support for their own stances, exploit similarities between tenets in their own field and accepted statements or positions properly developed within other areas of expertise. We illustrate the scope of application of our proposal with the analysis of a heavily methods-grounded, recent controversy in phylogeography, a biological subdiscipline concerned with the study of the historical causes of biogeographical variation through population genetics- and phylogenetics-based computer analyses of diversity in DNA sequences, both within species and between closely related taxa. Toward this end, we briefly summarize the arguments proposed by selected authors representing each side of the controversy: the ‘nested clade analysis’ school versus the ‘statistical phylogeography’ orientation. We claim that whereas both phylogeographic ‘research styles’ borrow epistemic credibility from sources such as formal logic, the familiarity of results from other scientific areas, the authority of prominent scientists, or the presumed superiority of quantitative vs. verbal reasoning, ‘theory’ plays essentially no role as a foundation of the controversy. Besides underscoring the importance of strictly methodological and other non-theoretical aspects of controversies in current evolutionary biology, our analysis suggests a perspective with potential usefulness for the re-examination of more general philosophy of biology issues, such as the nature of historical inference, rationality, justification, and objectivity

Repensar la enseñanza de las ciencias en la educación intercultural bilingüe : ¿un nuevo modelo de enseñanza?

La enseñanza de las ciencias naturales en la Educación Intercultural Bilingüe (EIB) re¬quiere de una reflexión sobre lo que implica la interculturalidad en la didáctica de las ciencias experi¬mentales. Creemos que hace falta plantear un modelo de enseñanza de las ciencias que sea inter e intra¬cultural, crítico y dialógico. Tanto el programa de investigación de Etnomatemática como la Ecología de Saberes (como parte del desarrollo de la Epistemología del Sur), pueden resultar las bases teóricas de un posible nuevo modelo de enseñanza de las ciencias en la EIB ya que parten de la idea de desnaturalizar el carácter hegemónico de la ciencia occidental

Analysis of the conceptions of learning assessment of outstanding primary education teachers

El documento presenta los resultados de una investigación cuya finalidad fue el estudio y análisis de las concepciones acerca de la evaluación del aprendizaje de cuatro docentes destacados según el Sistema de Evaluación Docente (SED) pertenecientes a diferentes establecimientos de Educación Básica de la Comuna de Curicó Chile, evaluados el año 2007. Se aplicó una metodología de casos tomando como base categorías preestablecidas, a través de entrevistas semiestructuradas, observaciones no participantes y análisis de documentos, para triangular la información. Los hallazgos dieron cuenta de concepciones con un rudimentario sustento teórico, con aspectos que se enmarcan bajo la línea de la evaluación para el aprendizaje, lo cual es coherente con la actual reforma educativa. Asimismo, es posible señalar importantes discrepancias entre la teoría de la evaluación y la práctica evaluativa de este grupo de profesores; no obstante, se enfatiza en la esencia formativa de la evaluación en el proceso de enseñanza-aprendizaje.O documento apresenta os resultados de uma investigação cuja finalidade foi o estudo e análise das concepções a respeito da avaliação da aprendizagem de quatro docentes marcantes segundo o Sistema de Avaliação Docente (SEDE) pertencentes a diferentes estabelecimentos de Educação Básica da Comuna de Curicó Chile, avaliados o ano 2007. Aplicou-se uma metodologia de casos tomando como baseie categorias preestablecidas, através de entrevistas semiestructuradas, observações não participantes e análises de documentos, para triangular a informação. Os achados deram conta de concepções com um rudimentario sustento teórico, com aspectos que se emolduram sob a linha da avaliação para a aprendizagem, o qual é coerente com a atual reforma educativa. Assim mesmo, é possível assinalar importantes discrepâncias entre a teoria da avaliação e a prática evaluativa deste grupo de professores; não obstante, enfatiza-se na essência formativa da avaliação no processo de ensino-aprendizagem.The article discusses the results of an investigation whose purpose was to characterize the conceptions of learning assessment of teachers rated as the Teacher Evaluation System belonging to different institutions of basic education in the borough of Curico, assessed in 2007. We applied a methodology based on cases a priori categories, through interviews, participant observations and document analysis to triangulate information. The findings indicate a rudimentary theoretical foundation in regard to aspects of assessment for learning, which is consistent with the current educational reform. It is possible to identify major discrepancies between theory and practice of evaluative assessment of this group of teachers; however, it emphasizes the essence of formative assessment in the teaching-learning process

Light-addressable liquid crystal polymer dispersed liquid crystal

Scattering-free liquid crystal polymer-dispersed liquid crystal polymer (LCPDLC) films are fabricated by combining a room temperature polymerizable liquid crystal (LC) monomer with a mesogenic photosensitive LC. The morphological and photosensitive properties of the system are analysed with polarized optical microscopy and high resolution scanning and transmission electron microscopy. A two-phase morphology comprised of oriented fibril-like polymeric structures interwoven with nanoscale domains of phase separated LC exists. The nanoscale of the structures enables an absence of scattering which allows imaging through the LCPDLC sample without optical distortion. The use of a mesogenic monomer enables much smaller phase separated domains as compared to nonmesogenic systems. All-optical experiments show that the transmitted intensity, measured through parallel polarizers, can be modulated by the low power density radiation (31 mW/cm2) of a suitable wavelength (532 nm). The reversible and repeatable transmission change is due to the photoinduced trans-cis photoisomerization process. The birefringence variation (0.01) obtained by optically pumping the LCPDLC films allow their use as an alloptical phase modulato

GnRH-induced cytosolic calcium oscillations in pituitary gonadotrophs: phase resetting by membrane depolarization

Cultured rat pituitary gonadotrophs under whole-cell voltage clamp conditions respond to the hypothalamic hormone GnRH with synchronized oscillatory changes in both cytosolic Ca2+ concentration ([Ca2+]i) and [Ca2+]i-activated, apamin-sensitive K+ current (IK(Ca)). We found, and report here for the first time, that in GnRH-stimulated cells a brief depolarizing pulse can elicit a transient [Ca2+]i rise similar to the endogenous cycle. Furthermore, Ca2+ entry during a single depolarizing pulse was found to shift the phase of subsequent endogenous [Ca2+]i oscillations, which thereafter continue to occur at their previous frequency before the pulse. Application of two consecutive depolarizing pulses showed that the size of the [Ca2+]i rise evoked by the second pulse depended on the time lapsed between two consecutive pulses, indicating that each endogenous or evoked [Ca2+]i rise cycle leaves the Ca2+ release mechanism of the gonadotroph in a refractory state. Recovery from this condition can be described by an exponential function of the time lapsed between the pulses (time constant of ca. 1 s). We propose that the underlying mechanism in both refractoriness after endogenous cycles and phase resetting by a brief pulse of Ca2+ entry involves the InsP3 receptor-channel molecule presumed to be located on the cytosolic aspect of the endoplasmic reticulum membrane