The 8 Learning Events Model: a Pedagogic Conceptual Tool Supporting Diversification of Learning Methods

This paper presents the 8 Learning Events Model (8LEM), a pedagogical reference framework which was used, in more than 100 online course, as a starting point for instructional planning. Besides supporting teachers in early stages of the learning design continuum, the paper shows how this learning/teaching model, as a professional development tool, prompts them to diversify the learning methods experienced by students in their courses. A two-pronged rationale about the importance of this diversification with respect to "mathetic" competence development and epistemology is also proposed to discussion. Keywords: mathetical competences, learning methods, teacher's professional development

The 8 Learning Events Model: a Pedagogic Conceptual Tool Supporting Diversification of Learning Methods

This paper presents the 8 Learning Events Model (8LEM), a pedagogical reference framework which was used, in more than 100 online course, as a starting point for instructional planning. Besides supporting teachers in early stages of the learning design continuum, the paper shows how this learning/teaching model, as a professional development tool, prompts them to diversify the learning methods experienced by students in their courses. A two-pronged rationale about the importance of this diversification with respect to "mathetic" competence development and epistemology is also proposed to discussion. Keywords: mathetical competences, learning methods, teacher's professional development

Segmentation 3D multi-objets d'images scanner cardiaques : une approche multi-agents

International audienceNous proposons une nouvelle méthode de segmentation permettant une détection multi-objets, semi-interactive et à caractère générique, appliquée à l'extraction de structures cardiaques en imagerie scanner multibarettes. L'approche proposée repose sur l'élaboration d'un schéma multi-agents combiné à une méthode de classification supervisée qui permet l'introduction d'a priori dans le processus de segmentation ainsi que des temps de calcul rapides. Le système multi-agents proposé est centralisé autour d'un agent communiquant qui contrôle une population d'agents situés dans l'image dont le rôle est d'assurer la segmentation au moyen d'interactions de type coopératif et compétitif. La méthode proposée a été testée sur plusieurs bases de données patient. Quelques résultats représentatifs sont finalement présentés et discutés

Investigations on Ni-Ti-Al ohmic contacts obtained on p-type 4H-SiC

International audienceTransfer Length Method (TLM) based-structures were fabricated on 0.8 µm-thick epitaxial p-type Silicon Carbide (4H-SiC) layers. TLM mesas were defined by a 2 µm height using an SF 6 /O 2 reactive ion etching. TLM metal patterns were obtained by a lift-off procedure and electron beam deposition of Ni, Ti, Al and Pt. The patterned samples were annealed in Argon ambient at temperature ranging from 700°C up to 1000°C in a RTA furnace with a rapid heating ramp (up to 50°C/s) to complete the ohmic contact with the p-type SiC layer. Specific contact resistances were extracted from current/voltage measurements. To identify and follow the profile evolution of constituting element in the contacts and at the SiC/contact interface, the ohmic contacts were characterized using Secondary Ion Mass Spectrometry and Energy-Dispersive X-Ray spectroscopy before and after annealing. Ohmic contacts are obtained only for the Ni/Ti/Al and Ni/Ti/Al/Ni stacking layers and not for the Ti/Al/Ti/Ni and Ti/Al/Ti/Pt/Ni compositions. The specific contact resistance of Ni/Ti/Al/Ni stacking layers was observed to decrease from 2.7×10-4  .cm 2 at 700°C and 6.3×10-5 .cm 2 at 750°C to a minimal value of 1.5×10-5  .cm 2 at 800°C. Ohmic contacts are obtained with a reproducibility of 80 %

The 8 Learning Events Model: a Pedagogic Conceptual Tool Supporting Diversification of Learning Methods Experienced by the Online Student

peer reviewedThis paper presents the 8 Learning Events Model (8LEM), a pedagogical reference framework which was used, in more than 100 online course, as a starting point for instructional planning. Besides supporting teachers in early stages of the learning design continuum, the paper shows how this learning/teaching model, as a professional development tool, prompts them to diversify the learning methods experienced by students in their courses. A two-pronged rationale about the importance of this diversification with respect to "mathetic" competence development and epistemology is also proposed to discussion

In vitro human embryonic stem cell hematopoiesis mimics MYB-independent yolk sac hematopoiesis

Although hematopoietic precursor activity can be generated in vitro from human embryonic stem cells, there is no solid evidence for the appearance of multipotent, self-renewing and transplantable hematopoietic stem cells. This could be due to short half-life of hematopoietic stem cells in culture or, alternatively, human embryonic stem cellinitiated hematopoiesis may be hematopoietic stem cell-independent, similar to yolk sac hematopoiesis, generating multipotent progenitors with limited expansion capacity. Since a MYB was reported to be an excellent marker for hematopoietic stem cell-dependent hematopoiesis, we generated a MYB-eGFP reporter human embryonic stem cell line to study formation of hematopoietic progenitor cells in vitro. We found CD34(+) hemogenic endothelial cells rounding up and developing into CD43(+) hematopoietic cells without expression of MYB-eGFP. MYB-eGFP+ cells appeared relatively late in embryoid body cultures as CD34(+) CD43(+) CD45(-/lo) cells. These MYB-eGFP(+) cells were CD33 positive, proliferated in IL-3 containing media and hematopoietic differentiation was restricted to the granulocytic lineage. In agreement with data obtained on murine Myb(-/-) embryonic stem cells, bright eGFP expression was observed in a subpopulation of cells, during directed myeloid differentiation, which again belonged to the granulocytic lineage. In contrast, CD14(+) macrophage cells were consistently eGFP-and were derived from eGFPprecursors only. In summary, no evidence was obtained for in vitro generation of MYB+ hematopoietic stem cells during embryoid body cultures. The observed MYB expression appeared late in culture and was confined to the granulocytic lineage

Defective CD4(+)CD25(+ )regulatory T cell functioning in collagen-induced arthritis: an important factor in pathogenesis, counter-regulated by endogenous IFN-γ

Mice with a deficiency in IFN-γ or IFN-γ receptor (IFN-γR) are more susceptible to collagen-induced arthritis (CIA), an experimental autoimmune disease that relies on the use of complete Freund's adjuvant (CFA). Here we report that the heightened susceptibility of IFN-γR knock-out (KO) mice is associated with a functional impairment of CD4(+)CD25(+ )T(reg )cells. Treatment of wild-type mice with depleting anti-CD25 antibody after CFA-assisted immunisation with collagen type II (CII) significantly accelerated the onset of arthritis and increased the severity of CIA. This is an indication of a role of T(reg )cells in the effector phase of CIA. IFN-γR deficiency did not affect the number of CD4(+)CD25(+ )T cells in the central and peripheral lymphoid tissues. In addition, CD4(+)CD25(+ )T cells isolated from naive IFN-γR KO mice had a normal potential to suppress T cell proliferation in vitro. However, after immunisation with CII in CFA, the suppressive activity of CD4(+)CD25(+ )T cells became significantly more impaired in IFN-γR-deficient mice. Moreover, expression of the mRNA for Foxp3, a highly specific marker for T(reg )cells, was lower. We further demonstrated that the effect of endogenous IFN-γ, which accounts for more suppressive activity in wild-type mice, concerns both T(reg )cells and accessory cells. Our results demonstrate that the decrease in T(reg )cell activity in CIA is counter-regulated by endogenous IFN-γ