27 research outputs found
Frecuencia y tipo de actividades de laboratorio que realizan profesores/as primarios en el area de las ciencias, en Santiago de Chile
El presente estudio tuvo como objetivos principal indagar sobre las percepciones que tienen los profesores primarios que realizan clases de ciencias en dos comunas de Santiago de Chile, sobre las actividades de laboratorio. Para ello se desarrolló un cuestionario con 13 preguntas cerradas y 32 afirmaciones de escala likert. La encuesta fue respondida por un total de 70 profesores de quinto y sexto nivel de educación primaria durante el periodo final de clases en el año 2008. Los resultados más importantes de la investigación señalan que: la actividad de laboratorio mas realizada son los experimentos y las menos la resolución de problemas; más del 50% de los profesores señala realizar dos o menos actividades de laboratorio en el año escolar y aquellos que realizan más actividades son los que están más de acuerdo con que estas fomentan la motivación de los niños por la ciencia
Episodic molecular outflow in the very young protostellar cluster Serpens South
The loss of mass from protostars, in the form of a jet or outflow, is a necessary counterpart to protostellar mass accretion. Outflow ejection events probably vary in their velocity and/or in the rate of mass loss. Such `episodic´ ejection events have been observed during the Class 0 protostellar phase (the early accretion stage), and continue during the subsequent class I phase that marks the first one million years of star formation. Previously observed episodic-ejection sources were relatively isolated; however, the most common sites of star formation are clusters. Outflows link protostars with their environment and provide a viable source of turbulence that is necessary for regulating star formation in clusters, but it is not known how an accretion-driven jet or outflow in a clustered environment manifests itself in its earliest stage. This early stage is important in establishing the initial conditions for momentum and energy transfer to the environment as the protostar and cluster evolve. Here we report that an outflow from a very young class 0 protostar, at the hub of the very active and filamentary Serpens South protostellar cluster, shows unambiguous episodic events. The 12CO (J=2-1) emission from the protostar reveals 22 distinct features of outflow ejecta, the most recent having the highest velocity. The outflow forms bipolar lobes --- one of the first detectable signs of star formation --- which originate from the peak of 1-mm continuum emission. Emission from the surrounding C18O envelope shows kinematics consistent with rotation and an infall of material onto the protostar. The data suggest that episodic accretion-driven outflow begins in the earliest phase of protostellar evolution, and that the outflow remains intact in a very clustered environment, probably providing efficient momentum transfer for driving turbulence. Fil: Plunkett, Adele L. . Yale University. Astronomy Department.; Estados UnidosFil: Arce, Héctor G.. Yale University. Astronomy Department.; Estados UnidosFil: Mardones, Diego . Universidad de Chile. Departamento de AstronomÃa; ChileFil: van Dokkum, Pieter . Yale University. Astronomy Department.; Estados UnidosFil: Dunham, Michael M. . Harvard-Smithsonian Center for Astrophysics; Estados UnidosFil: Fernandez Lopez, Manuel. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico La Plata. Instituto Argentino de Radioastronomia (i); ArgentinaFil: Gallardo, José. Joint ALMA Observatory; ChileFil: Cordero, Stuartt A. . Joint ALMA Observatory; Chil
New factors for protein transport identified by a genome-wide CRISPRi screen in mammalian cells
Protein and membrane trafficking pathways are critical for cell and tissue homeostasis. Traditional genetic and biochemical approaches have shed light on basic principles underlying these processes. However, the list of factors required for secretory pathway function remains incomplete, and mechanisms involved in their adaptation poorly understood. Here, we present a powerful strategy based on a pooled genome-wide CRISPRi screen that allowed the identification of new factors involved in protein transport. Two newly identified factors, TTC17 and CCDC157, localized along the secretory pathway and were found to interact with resident proteins of ER-Golgi membranes. In addition, we uncovered that upon TTC17 knockdown, the polarized organization of Golgi cisternae was altered, creating glycosylation defects, and that CCDC157 is an important factor for the fusion of transport carriers to Golgi membranes. In conclusion, our work identified and characterized new actors in the mechanisms of protein transport and secretion, and opens stimulating perspectives for the use of our platform in physiological and pathological contexts.Includes Wellcome Trust, MRC and H202
Dutch guideline on total hip prosthesis
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Longitudinal associations of lifestyle factors and weight status with insulin resistance (HOMA-IR) in preadolescent children: the large prospective cohort study IDEFICS
Thermophysical Properties of the Binary Mixture 1-Propylpyridinium Tetrafluoroborate with Methanol
Frecuencia y tipo de actividades de laboratorio que realizan profesores/as primarios en el area de las ciencias, en Santiago de Chile
El presente estudio tuvo como objetivos principal indagar sobre las percepciones que tienen los profesores primarios que realizan clases de ciencias en dos comunas de Santiago de Chile, sobre las actividades de laboratorio. Para ello se desarrolló un cuestionario con 13 preguntas cerradas y 32 afirmaciones de escala likert. La encuesta fue respondida por un total de 70 profesores de quinto y sexto nivel de educación primaria durante el periodo final de clases en el año 2008. Los resultados más importantes de la investigación señalan que: la actividad de laboratorio mas realizada son los experimentos y las menos la resolución de problemas; más del 50% de los profesores señala realizar dos o menos actividades de laboratorio en el año escolar y aquellos que realizan más actividades son los que están más de acuerdo con que estas fomentan la motivación de los niños por la ciencia