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Université de Fribourg

Fondements et perspectives de l'éducation préscolaire au Québec : pédagogie en contexte ludique

Bédard, Johanne ; Gurtner, Jean-Luc (Dir.) ; Retschitzki, Jean (Codir.)

Thèse de doctorat : Université de Fribourg, 2002.

Centrée sur les représentations et les pratiques d'utilisation du jeu au préscolaire, cette thèse s'inscrit dans le processus de réforme de l'enseignement au préscolaire, tel qu'amorcé récemment par le ministère de l'Éducation du Québec. Celle-ci fait également suite aux changements récents apportés par le ministère de la Famille et de l'Enfance au regard de la modélisation des...

Université de Fribourg

Optical imaging of the spatiotemporal dynamics of cerebral blood flow and oxidative metabolism in the rat barrel cortex

Weber, B. ; Burger, C. ; Wyss, M. T. ; Schulthess, G. K. von ; Scheffold, Frank ; Buck, Alfred

In: European Journal of Neuroscience, 2004, vol. 20, p. 2664-2670

Oxidative metabolism and cerebral blood flow (CBF) are two of the most important measures in neuroimaging. However, results from concurrent imaging of the two with high spatial and temporal resolution have never been published. We used flavoprotein autofluorescence (AF) and laser speckle imaging (LSI) in the anaesthetized rat to map oxidative metabolism and CBF in response to single vibrissa...

Université de Fribourg

Heterogeneous dynamics of coarsening systems

Mayer, P. ; Bissig, Hugo ; Berthier, L. ; Cipelletti, Luca ; Garrahan, J. P. ; Sollich, P. ; Trappe, Véronique

In: Physical Review Letters, 2004, vol. 93, p. 11570-11573

We show by means of experiments, theory, and simulations that the slow dynamics of coarsening systems displays dynamic heterogeneity similar to that observed in glass-forming systems. We measure dynamic heterogeneity via novel multipoint functions which quantify the emergence of dynamic, as opposed to static, correlations of fluctuations. Experiments are performed on a coarsening foam using...

Università della Svizzera italiana

Using information visualisation to facilitate instructors in web-based distance learning

Mazza, Riccardo ; Colombetti, Marco (Dir.)

Thèse de doctorat : Università della Svizzera italiana, 2004 ; 2004COM001.

The World Wide Web provides great opportunities for creating virtual classrooms of learners and instructors involved in distance education. Many software environments take advantage of the client-server communication on the Internet and support open and distance learning. Using environments called Course Management Systems (CMS), instructors can distribute information to students, produce content...

Université de Fribourg

Burckhardtsche Bestimmung der Raumgruppen II

Strebel, Ralph

In: Elemente der Mathematik, 2004, vol. 59, p. 1-18

Université de Fribourg

Burckhardtsche Bestimmung der Raumgruppen I

Strebel, Ralph

In: Elemente der Mathematik, 2003, vol. 58, p. 141-155

Université de Fribourg

Depolarization of backscattered linear lypolarized ligh

Rojas-Ochoa, Luis Fernando ; Lacoste, David ; Lenke, Ralf ; Schurtenberger, Peter ; Scheffold, Frank

In: Journal of the Optical Society of America: A, 2004, vol. 21, p. 1799-1804

We formulate a quantitative description of backscattered linearly polarized light with an extended photon diffusion formalism taking explicitly into account the scattering anisotropy parameter g of the medium. From diffusing wave spectroscopy measurements, the characteristic depolarization length for linearly polarized light, lp, is deduced. We investigate the dependence of this length on the...

Université de Fribourg

Colloidal gels—low-density disordered solid-like states

Trappe, Veronique ; Sandkühler, Peter

In: Current Opinion in Colloid & Interface Science, 2004, vol. 8, p. 494-500

The analogies between colloidal glasses and gels have stimulated an increased effort in recent years to unify the description of the transitions to these disordered solid-like states within a single conceptual framework. Mode coupling theory, which successfully describes the hard sphere colloidal glass transition, has been extended to describe the effect of weak attractions at large volume...

Université de Fribourg

Tracer microrheology of γ-dodecalactone induced gelation of aqueous starch dispersions

Heinemann, Cornelia ; Cardinaux, Frédéric ; Scheffold, Frank ; Schurtenberger, Peter ; Escher, Felix ; Conde-Petit, Béatrice

In: Carbohydrate Polymers, 2004, vol. 55, p. 155-161

We have studied the rheological properties of the natural biopolymer system starch in the presence of the gelation inducing flavor compound γ-dodecalactone. From optical microrheology, based on the multiple scattering of laser light (DWS), we deduce the frequency-dependent moduli G(ω) and G″(ω) of the gelling sample over the full frequency range. Our measurements demonstrate the inherent...