Beliefs and Responsibilities of Educational Stakeholders Concerning Student Success and Effective Principal Leadership

As elsewhere in Canada, the provincial educational system has adopted an accountability framework to improve student success by putting the emphasis on the rendering of accounts and production of a success plan. However, the implementation of school success plans is not always self-evident for socioeconomically disadvantaged communities. This case study highlights the difficulties experienced by a new principal in such a context. It shows the staff’s resistance to change when facing the success plan. For teaching purposes, it opens the discussion about the beliefs and responsibilities of all educational stakeholders concerning student success and about effective principal leadership

Cooling sequences and color-magnitude diagrams for cool white dwarfs with hydrogen-atmospheres

We present new cooling sequences, color-magnitude diagrams, and color-color diagrams for cool white dwarfs with pure hydrogen atmospheres down to an effective temperature \te=1500 K. We include a more detailed treatment of the physics of the fully-ionized interior, particularly an improved discussion of the thermodynamics of the temperature-dependent ion-ion and ion-electron contributions of the quantum, relativistic electron-ion plasma. The present calculations also incorporate accurate boundary conditions between the degenerate core and the outermost layers as well as updated atmosphere models including the H$_2$-H$_2$ induced-dipole absorption. We examine the differences on the cooling time of the star arising from uncertainties in the initial carbon-oxygen profile and the core-envelope $L$-$T_c$ relation. The maximum time delay due to crystallization-induced chemical fractionation remains substantial, from $\sim 1.0$ Gyr for 0.5 and 1.2 \msol white dwarfs to $\sim 1.5$ Gyr for 0.6 to 0.8 \msol white dwarfs, even with initial stratified composition profiles, and cannot be ignored in detailed white dwarf cooling calculations. These cooling sequences provide theoretical support to search for or identify old disk or halo hydrogen-rich white dwarfs by characterizing their mass and age from their observational signatures.Comment: 43 pages, Latex file, uses aasms4.sty, accepted for publication in ApJ (November 10 issue

L’évaluation des politiques en relations internationales : Le cas de la coopération franco-québécois en éducation

Taking into account recent policy analysis and evaluation theories which have been rarely applied international relations up till now, we attempted to construct a framework which we used to evaluate France-Quebec policies of cooperation in the field of education. Having identified the objectives of this cooperation, we verified wether these objectives were attained through the programme of integrated projects in education. Concerning the objective of creating international links it appears that it was realized when the programme was elaborated; however, the programme increases and officializes the exchanges, without that the Federal government intervenes, and leaves to the Quebec government the ability to impose its priorities. The integrated projects do not balance American influence, as it was the intention. The objectif of promotion of French language is partially realized through the publication of articles in French or the Frenchization of the bibliographies ; but the programme results in a perverse effect when French and Quebecer researchers publish jointly in English. The academic cooperation did not favorize teaching improvement of Quebecer professors, as it was an objective; however, it favorized research development. The results were partially attained, because this policy began without any study of the situation

Toward Precision Cosmochronology: A New C/O Phase Diagram for White Dwarfs

The continuous cooling of a white dwarf is punctuated by events that affect its cooling rate. Probably the most significant of those is the crystallization of its core, a phase transition that occurs once the C/O interior has cooled down below a critical temperature. This transition releases latent heat as well as gravitational energy due to the redistribution of the C and O ions during solidification, thereby slowing down the evolution of the white dwarf. The unambiguous observational signature of core crystallization - a pile-up of objects in the cooling sequence - was recently reported. However, existing evolution models struggle to quantitatively reproduce this signature, casting doubt on their accuracy when used to measure the ages of stellar populations. The timing and amount of the energy released during crystallization depend on the exact form of the C/O phase diagram. Using the advanced Gibbs-Duhem integration method and state-of-the-art Monte Carlo simulations of the solid and liquid phases, we have obtained a very accurate version of this phase diagram, allowing a precise modeling of the phase transition. Despite this improvement, the magnitude of the crystallization pile-up remains underestimated by current evolution models. We conclude that latent heat release and O sedimentation alone are not sufficient to explain the observations and that other unaccounted physical mechanisms, possibly $^{22}$Ne phase separation, play an important role.Comment: 4 pages, 2 figures. Accepted for publication in A&A Letter

Structural and core parameters of the hot B subdwarf KPD 0629-0016 from CoRoT g-mode asteroseismology

Context. The asteroseismic exploitation of long period, g-mode hot B subdwarf pulsators (sdBVs), undermined so far by limitations associated with ground-based observations, has now become possible, thanks to high quality data obtained from space such as those recently gathered with the CoRoT (COnvection, ROtation, and planetary Transits) satellite. Aims. We propose a detailed seismic analysis of the sdBVs star KPD 0629-0016, the first compact pulsator monitored with CoRoT, using the g-mode pulsations recently uncovered by that space-borne observatory during short run SRa03. Methods. We use a forward modeling approach on the basis of our latest sdB models, which are now suitable for the accurate com- putation of the g-mode pulsation properties. The simultaneous match of the independent periods observed in KPD 0629-0016 with those of the models leads objectively to the identification of the pulsation modes and, more importantly, to the determination of the structural and core parameters of the star. Results. The optimal model we found closely reproduces the 18 observed periods retained in our analysis at a 0.23% level on av- erage. These are identified as low-degree (l = 1 and 2), intermediate-order (k = −9 through −74) g-modes. The structural and core parameters for KPD 0629-0016 are the following (formal fitting errors only): Teff = 26 290 ± 530 K, log g = 5.450 ± 0.034, M∗ = 0.471 ± 0.002 M⊙, log (Menv/M∗) = −2.42 ± 0.07, log (1 − Mcore/M∗) = −0.27 ± 0.01, and Xcore(C+O) = 0.41 ± 0.01. We addition- ally derive an age of 42.6 ± 1.0 Myr after the zero-age extreme horizontal branch, the radius R = 0.214 ± 0.009 R⊙, the luminosity L = 19.7 ± 3.2 L⊙, the absolute magnitude MV = 4.23 ± 0.13, the reddening index E(B − V) = 0.128 ± 0.023, and the distance d = 1190 ± 115 pc. Conclusions. The advent of high-precision time-series photometry from space with instruments like CoRoT now allows as demon- strated with KPD 0629-0016 the full exploitation of g-modes as deep probes of the internal structure of these stars, in particular for determining the mass of the convective core and its chemical composition.Peer reviewe

LES CONCEPTIONS ET LES RESPONSABILITÉS DES INTERVENANTS SCOLAIRES PAR RAPPORT À LA RÉUSSITE DES ÉLÈVES ET LE LEADERSHIP DES DIRECTIONS D’ÉTABLISSEMENT

Comme ce fut le cas ailleurs au Canada, le système public d’éducation du Québec s’est vu doté d’un dispositif d’imputabilité visant l’amélioration de la réussite des élèves et comportant, entre autres, la production d’un plan de réussite par les établissements et une reddition de comptes. Or, la mise en œuvre de ce dispositif dans les établissements d’enseignement situés en milieu défavorisé apparait plus ardue que dans d’autres milieux en raison de l’ampleur des problèmes scolaires des élèves. Cette étude de cas illustre les difficultés rencontrées par une nouvelle direction d’établissement intervenant dans un tel contexte. Elle met en relief les résistances du personnel enseignant aux changements préconisés par la direction, notamment en ce qui concerne le plan de réussite proposé. À des fins d’enseignement, elle fournit des éléments de discussion sur les conceptions et les responsabilités des intervenants scolaires ainsi que sur l’exercice du leadership par les directions d’établissement

Pulsations in white dwarf stars

I will present a description of the six distinct families of pulsating white dwarfs that are currently known. Pulsations are present at various stages of the evolution (from hot, pre-white dwarfs to cool white dwarfs), at various stellar masses, and for various atmospheric compositions. In all of them, a mechanism linked to opacity changes along the evolution drives the oscillations. The existence of these oscillations offers the opportunity to apply asteroseismology for constraining physics inside white dwarfs. The direct comparison between observed and theoretical pulsation frequencies yields the global parameters (e.g. mass and radius) and internal structure and composition (e.g. envelope layering, core composition) of the star. The deep understanding of the driving mechanism provides stringent constraints on the physical conditions at work where oscillations are excited. I will present the major achievements in the field of white dwarf asteroseismology, as well as the needed improvements for coming years in this field of research

La gestion des Activités éducatives de la direction et le fonctionnement de l'école primaire

Many actors in the field of education assert that principals should pay closer attention to educational activities in order to ensure students' achievement. This paper presents a research conducted with 138 principals and 421 teachers which aimed at assessing the frequency of principals' interventions on managing educational activities in elementary schools in Quebec. In addition, this study examines the relations between principals' management of educational activities and the different aspect of the school's functioning. The results show that principals intervene more frequently in specific areas of management such as parents' involvement and the support of at-risk students rather than the supervision of teachers and students' performance. Hence, the quality of the school's functioning varies in the nature and frequency of the principal's intervention which illustrates the importance of their managerial work.Key words:    management of educational activities, educational leadership, school's functioning, students' achievement