61 research outputs found
Is there a middle grades canon? A survey methodology. American Reading Forum Annual Yearbook
Abstract Along with the development and implementation of the Common Core State Standards comes confusion on what texts middle grades teachers are supposed to use to support students' learning. Discussions on the existence of a middle school canon are inconclusive. To examine this issue, a survey was implemented asking English/Language Arts middle grades teachers to identify common literary titles they use in their classrooms. This article discusses the identification of the population, the survey design and data collection techniques used to collect data from a large sample of middle grade teachers, and the challenges faced in the administration and initial analysis of the survey. This articles hopes to inform and assist other researchers who plan to complete similar studies
MHD simulation of the formation of clumps and filaments in quiescent diffuse medium by thermal instability
We have used the AMR hydrodynamic code, MG, to perform idealised 3D MHD simulations of the formation of clumpy and filamentary structure in a thermally unstable medium without turbulence. A stationary thermally unstable spherical diffuse atomic cloud with uniform density in pressure equilibrium with low density surroundings was seeded with random density variations and allowed to evolve. A range of magnetic field strengths threading the cloud have been explored, from beta=0.1 to beta=1.0 to the zero magnetic field case (beta=infinity), where beta is the ratio of thermal pressure to magnetic pressure. Once the density inhomogeneities had developed to the point where gravity started to become important, self-gravity was introduced to the simulation. With no magnetic field, clouds and clumps form within the cloud with aspect ratios of around unity, whereas in the presence of a relatively strong field (beta=0.1) these become filaments, then evolve into interconnected corrugated sheets that are predominantly perpendicular to the magnetic field. With magnetic and thermal pressure equality (beta=1.0), filaments, clouds and clumps are formed. At any particular instant, the projection of the 3D structure onto a plane parallel to the magnetic field, i.e. a line of sight perpendicular to the magnetic field, resembles the appearance of filamentary molecular clouds. The filament densities, widths, velocity dispersions and temperatures resemble those observed in molecular clouds. In contrast, in the strong field case beta=0.1, projection of the 3D structure along a line of sight parallel to the magnetic field reveals a remarkably uniform structure
Planck intermediate results: XXXVIII. E- and B-modes of dust polarization from the magnetized filamentary structure of the interstellar medium
The quest for a B-mode imprint from primordial gravity waves on the polarization of the cosmic microwave background (CMB) requires the characterization of foreground polarization from Galactic dust. We present a statistical study of the filamentary structure of the 353 GHz Planck Stokes maps at high Galactic latitude, relevant to the study of dust emission as a polarized foreground to the CMB. We filter the intensity and polarization maps to isolate filaments in the range of angular scales where the power asymmetry between E-modes and B-modes is observed. Using the Smoothed Hessian Major Axis Filament Finder (SMAFF), we identify 259 filaments at high Galactic latitude, with lengths larger or equal to 2\uc2\ub0 (corresponding to 3.5 pc in length for a typical distance of 100 pc). These filaments show a preferred orientation parallel to the magnetic field projected onto the plane of the sky, derived from their polarization angles. We present mean maps of the filaments in Stokes I, Q, U, E, and B, computed by stacking individual images rotated to align the orientations of the filaments. Combining the stacked images and the histogram of relative orientations, we estimate the mean polarization fraction of the filaments to be 11%. Furthermore, we show that the correlation between the filaments and the magnetic field orientations may account for the E and B asymmetry and the C\ue2\u84\u93TE/C\ue2\u84\u93EEratio, reported in the power spectra analysis of the Planck353 GHz polarization maps. Future models of the dust foreground for CMB polarization studies will need to take into account the observed correlation between the dust polarization and the structure of interstellar matter
Hygiene and health, month of July
La imagen contiene una noticia acerca de la mortalidad durante el mes de julio clasificada por edades mostranto las cifras totales de nacimientos y defunciones de las personas habitantes de la ciudad de Bogotá durante el mes de Julio.
Noticia publicada en el Registro Municipal, año XXXIII, del 14 de Ocutubre de 1911.The image contains news about mortality during the month of July classified by age, showing the total numbers of births and deaths of the inhabitants of the city of Bogotá during the month of July.
News published in the Municipal Registry, year XXXIII, October 14, 1911
Table of mortality classified by age, in the month of October 1910
La imagen contiene una noticia acerca de la mortalidad en Bogotá en el mes de Octubre clasificada por edades, nacimientos y matrimonios clasificados por legitimos y naturales en las diferentes zonas de Bogotá, mostrando los resultados de los datos del estudio.
Noticia publicada en el Registro Municipal, año XXXIII, No. 1033, 17 de Febrero 1911The image contains news about mortality in Bogotá in the month of October classified by age, births and marriages classified by legitimate and natural in the different areas of Bogotá, showing the results of the study data.
News published in the Municipal Registry, year XXXIII, No. 1033, February 17, 191
Quantifying the interplay between gravity and magnetic field in molecular clouds – a possible multiscale energy equipartition in NGC 6334
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