Circadian and Metabolic Effects of Light: Implications in Weight Homeostasis and Health

Daily interactions between the hypothalamic circadian clock at the suprachiasmatic nucleus (SCN) and peripheral circadian oscillators regulate physiology and metabolism to set temporal variations in homeostatic regulation. Phase coherence of these circadian oscillators is achieved by the entrainment of the SCN to the environmental 24-h light:dark (LD) cycle, coupled through downstream neural, neuroendocrine, and autonomic outputs. The SCN coordinate activity and feeding rhythms, thus setting the timing of food intake, energy expenditure, thermogenesis, and active and basal metabolism. In this work, we will discuss evidences exploring the impact of different photic entrainment conditions on energy metabolism. The steady-state interaction between the LD cycle and the SCN is essential for health and wellbeing, as its chronic misalignment disrupts the circadian organization at different levels. For instance, in nocturnal rodents, non-24 h protocols (i.e., LD cycles of different durations, or chronic jet-lag simulations) might generate forced desynchronization of oscillators from the behavioral to the metabolic level. Even seemingly subtle photic manipulations, as the exposure to a "dim light" scotophase, might lead to similar alterations. The daily amount of light integrated by the clock (i.e., the photophase duration) strongly regulates energy metabolism in photoperiodic species. Removing LD cycles under either constant light or darkness, which are routine protocols in chronobiology, can also affect metabolism, and the same happens with disrupted LD cycles (like shiftwork of jetlag) and artificial light at night in humans. A profound knowledge of the photic and metabolic inputs to the clock, as well as its endocrine and autonomic outputs to peripheral oscillators driving energy metabolism, will help us to understand and alleviate circadian health alterations including cardiometabolic diseases, diabetes, and obesity.Fil: Plano, Santiago Andrés. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires". Instituto de Investigaciones Biomédicas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas; ArgentinaFil: Casiraghi, Leandro Pablo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Cronobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Garcia Moro, Paula. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Cronobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Paladino, Natalia. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Cronobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Golombek, Diego Andrés. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Cronobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Chiesa, Juan José. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Cronobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Re-conceptualizing Teachers’ Narrative Inquiry as Professional Development

We offer a more nuanced characterization of teachers’ narrative inquiry as professional development (Johnson and Golombek, 2002) by grounding our definition of and empirical research on teachers’ narrative inquiry from a Vygotskian sociocultural theoretical perspective. Our goal is to reaffirm our belief in the educational value of teachers’ narrative inquiry as “systematic exploration that is conducted by teachers and for teachers through their own stories and language” (p. 6), while empirically documenting the crucial role of teacher educators in creating mediational spaces, dialogic interactions, and pedagogical tools for teachers’ narrative inquiry to flourish as professional development. It is also our goal to re-conceptualize teachers’ narrative inquiry as unbounded by time and place, and as a more fluid and emerging process.Ofrecemos una caracterización más detallada del uso de las indagaciones narrativas de los docentes para su desarrollo profesional (Johnson y Golombek, 2002), para lo cual basamos nuestra definición de y la investigación empírica sobre la investigación narrativa de los docentes en la teoría sociocultural de Vygostky. Nuestro propósito consiste en reafirmar nuestra convicción acerca del valor educativo de la investigación narrativa de los docentes como una “exploración sistemática que es conducida por y para los docentes por medio de sus propios relatos y lenguaje” (p. 6). Asimismo, documentamos de manera empírica el papel crucial de los formadores de docentes para crear espacios mediacionales, las interacciones dialógicas y herramientas pedagógicas que promuevan la indagación narrativa de los docentes como forma de desarrollo profesional. También pretendemos re-conceptualizar la indagación narrativa de los docentes como un proceso sin limitantes de tiempo y espacio, y con una naturaleza fluida y emergente

The transformative power of narrative in second language teacher education.

Within the field of second language teacher education (SLTE), narrative has largely functioned as a vehicle for teacher inquiry, based on the assumption that such inquiry will ultimately bring about productive change in teachers and their teaching practices. Less attention has been paid to documenting what this change looks like or how engagement in narrative activities fosters teacher professional development. From a Vygotskian sociocultural theoretical perspective, we argue that the transformative power of narrative lies in its ability to ignite cognitive processes that can foster teacher professional development. We tease out the complex ways in which narrative functions as a mediational tool-narrative as externalization, verbalization, and systematic examination-in fostering teacher professional development, and we highlight the interplay between these functions by tracing teacher professional development in two teacher-authored narrative inquiries. We then turn to the centrality of narrative as a vehicle for teacher inquiry in transforming the field of SLTE itself. Specifically, we highlight various outlets, in both center and periphery contexts, where the products of teachers' narrative activities are functioning as a tool for knowledge-building and professional development practices that are working in consort to transform the professional landscape that constitutes the field of SLTE