Homogenenized interface model describing defects periodically distributed on a surface

Titre du résumé français joint : Modèle d'interface homogénéisée décrivant des défauts périodiquement répartis sur une surfaceNational audienceWe undertake the homogenization of a three-dimensional elastic medium, which contains heterogeneities localized on a surface. These can be either reinforcements, like steel reinforcements in concrete, or defects, like microcracks periodically distributed. We propose a simple model describing the effective behaviour of these heterogeneities. This model, formulated in an energetic framework, com- bines an elastic interface behaviour with that of a membrane. Its interest is discussed through several applications.See http://hal.archives-ouvertes.fr/docs/00/59/28/84/ANNEX/r_O1H9ABAW.pd

In-forest education without owning a forest - the HAFL approach to solve this challenge

The forest science education at the School of Agricultural, Forest and Food Sciences (HAFL, Hochschule für Agrar-, Forst- und Lebensmittelwissenschaften) uses in-forest education extensively. However, HAFL does neither possess its own forest area, nor does it have a land-lease or other long-lasting contract providing forest access. Therefore, a blended strategy is used to give access to forest areas for teaching purpose. Depending on subject different approaches are used, which are presented here

Calcium-stores mediate adaptation in axon terminals of Olfactory Receptor Neurons in Drosophila

<p>Abstract</p> <p>Background</p> <p>In vertebrates and invertebrates, sensory neurons adapt to variable ambient conditions, such as the duration or repetition of a stimulus, a physiological mechanism considered as a simple form of non-associative learning and neuronal plasticity. Although various signaling pathways, as cAMP, cGMP, and the inositol 1,4,5-triphosphate receptor (InsP₃R) play a role in adaptation, their precise mechanisms of action at the cellular level remain incompletely understood. Recently, in <it>Drosophila</it>, we reported that odor-induced Ca²⁺-response in axon terminals of olfactory receptor neurons (ORNs) is related to odor duration. In particular, a relatively long odor stimulus (such as 5 s) triggers the induction of a second component involving intracellular Ca²⁺-stores.</p> <p>Results</p> <p>We used a recently developed <it>in-vivo </it>bioluminescence imaging approach to quantify the odor-induced Ca²⁺-activity in the axon terminals of ORNs. Using either a genetic approach to target specific RNAs, or a pharmacological approach, we show that the second component, relying on the intracellular Ca²⁺-stores, is responsible for the adaptation to repetitive stimuli. In the antennal lobes (a region analogous to the vertebrate olfactory bulb) ORNs make synaptic contacts with second-order neurons, the projection neurons (PNs). These synapses are modulated by GABA, through either GABAergic local interneurons (LNs) and/or some GABAergic PNs. Application of GABAergic receptor antagonists, both GABA_Aor GABA_B, abolishes the adaptation, while RNAi targeting the GABAB_R(a metabotropic receptor) within the ORNs, blocks the Ca²⁺-store dependent component, and consequently disrupts the adaptation. These results indicate that GABA exerts a feedback control. Finally, at the behavioral level, using an olfactory test, genetically impairing the GABA_BR or its signaling pathway specifically in the ORNs disrupts olfactory adapted behavior.</p> <p>Conclusion</p> <p>Taken together, our results indicate that a relatively long lasting form of adaptation occurs within the axon terminals of the ORNs in the antennal lobes, which depends on intracellular Ca²⁺-stores, attributable to a positive feedback through the GABAergic synapses.</p

The Gift and the meaning-giving subject: A Reading of Given Time

In this essay the relation between justice and the gift in Derrida’s thinking is explored. The essay shows that an understanding of the ontological difference or the relation between Being and beings in Heidegger’s thinking as well as Freud’s speculations on the death drive are essential to comprehend the ‘concept’ or ‘notion’ of différance as well as the gift in Derrida’s thinking. The analysis points to the complexity of Derrida’s thinking in his contemplation of the relation between justice and law and the need for a broader investigation to understand what is at stake in this regard. An exploration of the gift shows that Derrida’s thinking on justice is not ‘relativistic’ as is often assumed and that the gift can in a certain way function as a ‘guide’ in questions of constitutional interpretation