Hierarchical Event Descriptors (HED): Semi-Structured Tagging for Real-World Events in Large-Scale EEG.

Real-world brain imaging by EEG requires accurate annotation of complex subject-environment interactions in event-rich tasks and paradigms. This paper describes the evolution of the Hierarchical Event Descriptor (HED) system for systematically describing both laboratory and real-world events. HED version 2, first described here, provides the semantic capability of describing a variety of subject and environmental states. HED descriptions can include stimulus presentation events on screen or in virtual worlds, experimental or spontaneous events occurring in the real world environment, and events experienced via one or multiple sensory modalities. Furthermore, HED 2 can distinguish between the mere presence of an object and its actual (or putative) perception by a subject. Although the HED framework has implicit ontological and linked data representations, the user-interface for HED annotation is more intuitive than traditional ontological annotation. We believe that hiding the formal representations allows for a more user-friendly interface, making consistent, detailed tagging of experimental, and real-world events possible for research users. HED is extensible while retaining the advantages of having an enforced common core vocabulary. We have developed a collection of tools to support HED tag assignment and validation; these are available at hedtags.org. A plug-in for EEGLAB (sccn.ucsd.edu/eeglab), CTAGGER, is also available to speed the process of tagging existing studies

Transplantation of schistosome sporocysts between host snails: A video guide.

Schistosomiasis is an important parasitic disease, touching roughly 200 million people worldwide. The causative agents are different Schistosoma species. Schistosomes have a complex life cycle, with a freshwater snail as intermediate host. After infection, sporocysts develop inside the snail host and give rise to human dwelling larvae. We present here a detailed step-by-step video instruction in English, French, Spanish and Portuguese that shows how these sporocysts can be manipulated and transferred from one snail to another. This procedure provides a technical basis for different types of ex vivo modifications, such as those used in functional genomics studies

Transplantation of schistosome sporocysts between host snails::A video guide

Schistosomiasis is an important parasitic disease, touching roughly 200 million people worldwide. The causative agents are different Schistosoma species. Schistosomes have a complex life cycle, with a freshwater snail as intermediate host. After infection, sporocysts develop inside the snail host and give rise to human dwelling larvae. We present here a detailed step-by-step video instruction in English, French, Spanish and Portuguese that shows how these sporocysts can be manipulated and transferred from one snail to another. This procedure provides a technical basis for different types of ex vivo modifications, such as those used in functional genomics studies

Manager ou servir ? Le service public aux prises avec le nouveau management public

International audienceLes services publics sont au cœur des préoccupations des Français. Lors de la crise récente, ils ont fonctionné comme un bouclier, atténuant les effets dévastateurs de celle-ci sur les citoyens.Dans les discours gouvernementaux, les services publics sont également centraux. Sans jamais les attaquer de front, on prétend vouloir les pérenniser en les rendant plus efficaces et plus responsables… Ce livre s'interroge sur la réalité des effets des politiques de ce qu'on appelle «Nouveau management public» sur les agents des services publics et en particulier sur ses cadres intermédiaires. Dans les domaines de la santé, de la justice, de l'éducation, faut-il désormais choisir entre manager et servir?Les professionnels de ces domaines disent tous à quel point la multiplication des contraintes a fait évoluer leur travail. Leur sentiment est d'être constamment entre le marteau et l'enclume, constamment aux prises avec des injonctions paradoxales : faire plus avec moins, être plus autonome tout en étant confronté à des prescriptions centralisées impératives.Cet ouvrage souligne aussi les capacités de résistance des corps professionnels et de l'institution, capables d'inventer des modalités d'actions et de services nouvelle

Manager ou servir. Les services publics aux prises avec le nouveau management public

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How granular vortices can help understanding rheological and mixing properties of dense granular flows

Dense granular flows exhibit fascinating kinematic patterns characterised by strong fluctuations in grain velocities. In this paper, we analyse these fluctuations and discuss their possible role on macroscopic properties such as effective viscosity, non-locality and shear-induced diffusion. The analysis is based on 2D experimental granular flows performed with the stadium shear device and DEM simulations. We first show that, when subjected to shear, grains self-organised into clusters rotating like rigid bodies. The average size of these so-called granular vortices is found to increase and diverge for lower inertial numbers, when flows decelerate and stop. We then discuss how such a microstructural entity and its associated internal length scale, possibly much larger than a grain, may be used to explain two important properties of dense granular flows: (i) the existence of shear-induced diffusion of grains characterised by a shear-rate independent diffusivity and (ii) the development of boundary layers near walls, where the viscosity is seemingly lower than the viscosity far from walls

How granular vortices can help understanding rheological and mixing properties of dense granular flows

Dense granular flows exhibit fascinating kinematic patterns characterised by strong fluctuations in grain velocities. In this paper, we analyse these fluctuations and discuss their possible role on macroscopic properties such as effective viscosity, non-locality and shear-induced diffusion. The analysis is based on 2D experimental granular flows performed with the stadium shear device and DEM simulations. We first show that, when subjected to shear, grains self-organised into clusters rotating like rigid bodies. The average size of these so-called granular vortices is found to increase and diverge for lower inertial numbers, when flows decelerate and stop. We then discuss how such a microstructural entity and its associated internal length scale, possibly much larger than a grain, may be used to explain two important properties of dense granular flows: (i) the existence of shear-induced diffusion of grains characterised by a shear-rate independent diffusivity and (ii) the development of boundary layers near walls, where the viscosity is seemingly lower than the viscosity far from walls

Eddy Viscosity in Dense Granular Flows

International audienceWe present a seminal set of experiments on dense granular flows in the stadium shear geometry. The advantage of this geometry is that it produces steady shear flow over large deformations, in which the shear stress is constant. The striking result is that the velocity profiles exhibit an S shape, and are not linear as local constitutive laws would predict. We propose a model that suggests this is a result of wall perturbations which span through the system due to the nonlocal behavior of the material. The model is analogous to that of eddy viscosity in turbulent boundary layers, in which the distance to the wall is introduced to predict velocity profiles. Our findings appear pivotal in a number of experimental and practical situations involving dense granular flows next to a boundary. They could further be adapted to other similar materials such as dense suspensions, foams, or emulsions

Long-range wall perturbations in dense granular flows

International audienceWe explore how the rheology of dense granular flows is affected by the presence of sidewalls. The study is based on discrete element method simulations of plane-shear flows between two rough walls, prescribing both the normal stress and the shear rate. Results confirm previous observations for different systems: large layers near the walls develop where the local viscosity is not constant, but decreases when approaching the walls. The size of these layers can reach several dozen grain diameters, and is found to increase when the flow decelerates, as a power law of the inertial number. Two non-local models are found to adequately explain such features, namely the kinetic elasto-plastic fluidity (KEP) model and the eddy viscosity model (EV). The analysis of the internal kinematics further shows that the vorticity and its associated length scale may be a key component of these non-local behaviours