Multiliteracies, Pedagogy and Identities:Teacher and Student Voices from a Toronto Elementary School

In this article, I draw on an ethnographic case study of one Toronto elementary school, as part of a Canada‐wide action research project: Multiliteracy Project (www.multiliteracies.ca). I have explored how Perminder, a grade‐4 teacher, devel‐ oped a multiliteracies pedagogy, drawing on her own and her students’ identities and linguistic and cultural forms of capital to create learning opportunities for all students to access the English mainstream curriculum. Alternative pedagogical choices in‐ cluded students’ creation of multimodal dual language “identity texts” (Cummins, Bismilla, Cohen, Giampapa, & Leoni, 2005a), and identity work, expanding literacy practices valued within Canadian classrooms. Key words: critical pedagogies, critical literacies, ESL/EAL, identities, Multilit‐ eracy Project, urban schools Dans cet article, l’auteure part d’une étude de cas ethnographique portant sur une école primaire de Toronto, étude réalisée dans le cadre d’un projet de recherche‐ action pancanadien, The Multiliteracy Project (www.multiliteracies.ca). Elle analyse comment Perminder, une enseignante de 4e année, a mis au point une pédagogie en matière de multilitératies. Puisant dans sa propre identité et dans celles de ses élèves ainsi que dans diverses formes de capital linguistiques et culturelles, elle offre à tous ses élèves la possibilité d’apprendre et ainsi d’avoir accès au curriculum standard en anglais. Parmi les choix pédagogiques novateurs figuraient la création par les élèves de « textes identitaires » (Cummins et coll. 2005a) multimodaux en deux langues et des travaux portant sur l’identité, élargissant ainsi les pratiques en matière de littéra‐ tie jugées utiles dans les classes canadiennes. Mots clés : pédagogies critiques, littératies critiques, ESL/EAL, identités, The Multiliteracy Project, écoles urbaines.

The Origin of Enhanced Activity in the Suns of M67

We report the results of the analysis of high resolution photospheric line spectra obtained with the UVES instrument on the VLT for a sample of 15 solar-type stars selected from a recent survey of the distribution of H and K chromospheric line strengths in the solar-age open cluster M67. We find upper limits to the projected rotation velocities that are consistent with solar-like rotation (i.e., v sini ~< 2-3 km/s) for objects with Ca II chromospheric activity within the range of the contemporary solar cycle. Two solar-type stars in our sample exhibit chromospheric emission well in excess of even solar maximum values. In one case, Sanders 1452, we measure a minimum rotational velocity of vsini = 4 +/- 0.5 km/s, or over twice the solar equatorial rotational velocity. The other star with enhanced activity, Sanders 747, is a spectroscopic binary. We conclude that high activity in solar-type stars in M67 that exceeds solar levels is likely due to more rapid rotation rather than an excursion in solar-like activity cycles to unusually high levels. We estimate an upper limit of 0.2% for the range of brightness changes occurring as a result of chromospheric activity in solar-type stars and, by inference, in the Sun itself. We discuss possible implications for our understanding of angular momentum evolution in solar-type stars, and we tentatively attribute the rapid rotation in Sanders 1452 to a reduced braking efficiency.Comment: accepted by Ap

The ultraviolet variability of the T Tauri star RW Aurigae

Between 1978 and 1979 the visible brightness of RW Aurigae increased by 0.9 mag. During this time (1) CIV and SiIV increased by factors of 2 to 4 while the lower ionization lines remained unchanged; (2) the fluorescent OI line increased by a factor of 8; (3) the shell spectrum changed from emission to absorption; and (4) the ultraviolet continuum brightened by 2.3 mag. On a time scale of a week the continuum varied by as much as 0.8 mag., but the MgII emission lines showed no variability over 10 percent. An active chromosphere, transition region, and envelope cooled by mass loss are hypothesized in order to explain the ultraviolet observations of RW Aur

The Transit Light Source Effect: False Spectral Features and Incorrect Densities for M-dwarf Transiting Planets

Transmission spectra are differential measurements that utilize stellar illumination to probe transiting exoplanet atmospheres. Any spectral difference between the illuminating light source and the disk-integrated stellar spectrum due to starspots and faculae will be imprinted in the observed transmission spectrum. However, few constraints exist for the extent of photospheric heterogeneities in M dwarfs. Here, we model spot and faculae covering fractions consistent with observed photometric variabilities for M dwarfs and the associated 0.3-5.5 $\mu$m stellar contamination spectra. We find that large ranges of spot and faculae covering fractions are consistent with observations and corrections assuming a linear relation between variability amplitude and covering fractions generally underestimate the stellar contamination. Using realistic estimates for spot and faculae covering fractions, we find stellar contamination can be more than $10 \times$ larger than transit depth changes expected for atmospheric features in rocky exoplanets. We also find that stellar spectral contamination can lead to systematic errors in radius and therefore the derived density of small planets. In the case of the TRAPPIST-1 system, we show that TRAPPIST-1's rotational variability is consistent with spot covering fractions $f_{spot} = 8^{+18}_{-7}\%$ and faculae covering fractions $f_{fac} = 54^{+16}_{-46}\%$. The associated stellar contamination signals alter transit depths of the TRAPPIST-1 planets at wavelengths of interest for planetary atmospheric species by roughly 1-15 $\times$ the strength of planetary features, significantly complicating $JWST$ follow-up observations of this system. Similarly, we find stellar contamination can lead to underestimates of bulk densities of the TRAPPIST-1 planets of $\Delta(\rho) = -3^{+3}_{-8} \%$, thus leading to overestimates of their volatile contents.Comment: accepted for publication in Ap

Policy-driven planning in coalitions - A case study

(c)IFAAMASPeer reviewedPostprin

UV chromospheric and circumstellar diagnostic features among F supergiant stars

A survey of F supergiant stars to evaluate the extension of chromospheric and circumstellar characteristics commonly observed in the slightly cooler G, K, and M supergiant is discussed. An ultraviolet survey was elected since UV features of Mg II and Fe II might persist in revealing outer atmosphere phenomena even among F supergiants. The encompassed spectral types F0 to G0, and luminosity classes Ib, Ia, and Ia-0. In addition, the usefulness of the emission line width-to-luminosity correlation for the G-M stars in both the Ca II and Mg II lines is examined

Estimates of Active Region Area Coverage through Simultaneous Measurements of He I λλ\lambda\lambda 5876 and 10830 Lines

Simultaneous, high-quality measurements of the neutral helium triplet features at 5876~\AA\ and 10830~\AA, respectively, in a sample of solar-type stars are presented. The observations were made with ESO telescopes at the La Silla Paranal Observatory under program ID 088.D-0028(A) and MPG Utility Run for FEROS 088.A-9029(A). The equivalent widths of these features combined with chromospheric models are utilized to infer the fractional area coverage, or filling factor, of magnetic regions outside of spots. We find that the majority of the sample is characterized by filling factors less than unity. However, discrepancies occur among the coolest K-type and warmest and most rapidly rotating F-type dwarf stars. We discuss these apparently anomalous results and find that in the case of K-type stars they are an artifact of the application of chromospheric models best suited to the Sun than to stars with significantly lower $T_\mathrm{eff}$. The case of the F-type rapid rotators can be explained with the measurement uncertainties of the equivalent widths, but they may also be due to a non-magnetic heating component in their atmospheres. With the exceptions noted above, preliminary results suggest that the average heating rates in the active regions are the same from one star to the other, differing in the spatially integrated, observed level of activity due to the area coverage. Hence, differences in activity in this sample are mainly due to the filling factor of active regions.Comment: Accepted for publication in The Astrophysical Journa

Second Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun, volume 1

Solar and stellar atmospheric phenomena and their fundamental physical properties such as gravity, effective temperature and rotation rate, which provides the range in parameter space required to test various theoretical models were investigated. The similarity between solar activity and stellar activity is documented. Some of the topics discussed are: atmospheric structure, magnetic fields, solar and stellar activity, and evolution