1,129 research outputs found

    En quoi les dispositifs territoriaux de la gestion de l’eau peuvent-ils ĂȘtre efficaces

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    AprĂšs trente ans de mise en oeuvre des dispositifs issus de la territorialisation de la politique de l’eau, le recul est suffisant pour interroger leur contribution Ă  la prĂ©servation ou Ă  l’amĂ©lioration de l’état Ă©cologique des hydrosystĂšmes, devenus un impĂ©ratif europĂ©en depuis 2000. À partir de l’exemple de la gestion de la riviĂšre DrĂŽme, cet article nous explique le processus de territorialisation ainsi que les conditions de l’efficacitĂ© d’une politique environnementale Ă  l’échelle locale

    Les ressorts territoriaux de la gestion de l'eau sont-ils gages d'efficacité environnementale ? Analyse des dimensions territorialisées et territorialisantes des dispositifs de gestion des eaux dans la vallée de la DrÎme (1980-2011)

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    National audienceLes dispositifs de Contrat de riviĂšre et de SchĂ©ma d’AmĂ©nagement et de Gestion des Eaux font partie des nouveaux modes d’action publique faisant le pari d’un gain d’efficacitĂ© par leur territorialisation. En matiĂšre environnementale, cette efficacitĂ© repose sur la capacitĂ© des gestionnaires de l’eau Ă  transformer les pratiques responsables des atteintes aux milieux aquatiques et Ă  obtenir pour ce faire des marges et moyens d’action. Si, dans les derniĂšres dĂ©cennies, la politique française de l’eau s’est territorialisĂ©e, dans la mesure oĂč elle est modelĂ©e par les spĂ©cificitĂ©s locales, elle possĂšde Ă©galement une dimension territorialisante, dans le sens oĂč elle conforte, dĂ©fait ou modifie les territorialitĂ©s existantes. Cette recherche pose l’hypothĂšse que l’efficacitĂ© environnementale de ces dispositifs de gestion locale des eaux dĂ©pend de la maniĂšre dont les acteurs qui les mettent en place se saisissent de leurs dimensions territoriales. Elle explore les stratĂ©gies territoriales dĂ©ployĂ©es dans l’élaboration et la mise en Âœuvre des projets de gestion de l’eau. Elle identifie et qualifie les diffĂ©rents ressorts territoriaux mobilisĂ©s et analyse leurs implications en termes de modification des reprĂ©sentations et des pratiques des usagers de l’eau et in fine de l’état environnemental des ressources et des milieux aquatiques. La dĂ©monstration s’appuie sur le cas empirique de la vallĂ©e de la DrĂŽme, qui offre une intĂ©ressante perspective diachronique sur trois dĂ©cennies avec la mise en Âœuvre de deux contrats de riviĂšre puis d’un SAGE, aujourd’hui en cours de rĂ©vision. Les rĂ©sultats de la recherche portent sur les mĂ©canismes et les conditions par lesquels la gestion territoriale de l’eau peut ĂȘtre gage d’efficacitĂ© environnementale. Des facteurs dĂ©terminants sont mis en Ă©vidence : (i) la mise en synergie des projets de dĂ©veloppement territorial avec ceux de la gestion de l’eau ; (ii) l’activation de ressorts territoriaux de type identitaire et (iii) les intentions et les capacitĂ©s d’action de la gestion intentionnelle de l’eau. Les structures intercommunales prĂ©sentent de bonnes dispositions pour activer et mobiliser les ressorts territoriaux de la gestion de l’eau en raison : (i) de leur taille moyenne et de leur position intermĂ©diaire, qui leur permettent d’obtenir les moyens d’actions et les marges de manÂœuvre nĂ©cessaires Ă  leurs projets auprĂšs des partenaires supra-locaux tout en crĂ©ant et conservant la confiance des usagers de l’eau et (ii) de leur double compĂ©tence en matiĂšre de dĂ©veloppement territorial et dans le domaine environnemental. Au sein de ces structures, les binĂŽmes Ă©lu/ agent de dĂ©veloppement constituent les moteurs d’activation des ressorts territoriaux de la gestion durable de l’eau

    Romanticism, Symbolism and Onomastics in Tolkien’s Legendarium

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    E.B. Burgum once wrote in the Kenyon Review (1941): “He who seeks to define Romanticism is entering a hazardous occupation which has claimed many victims”. However there is no denying that sensibility is one of the consensual pointers. And if one seeks to explore Professor Tolkien’s motives behind the unfolding of his Legendarium, there is again no denying that his self-avowed extreme sensitivity to words and languages is not only a pointer but also lies at the root of his entire writing process. Such visceral fascination for the beauty and musicality of words can be found in the etymology and symbolism of personal and place names throughout Middle-earth. As a contribution to the study of romanticism in Tolkien’s works, this paper examines the possible characteristics of this complex movement that find an echo in the author’s onomastic sub-creation and the latter’s subsequent relation to the characters, places and objects in Middle-earth

    Perspectives on Just War in Tolkien’s Legendarium

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    The AinulindalĂ« shows that in Middle-earth war is not an option: the seeds of harmony and discordance are sown at the outset and between the alpha and the omega, races and individuals will attune to the Great Music or take part in the discordance. Their trajectories highlight the perspectives of their Creator or, from the standpoint of the reader, of their sub-creator. Owing to the centrality of warfare in the history of Middle-earth, this paper will look into the motivations of the races and people engaged in conflicts, whether they be waged with seemingly justifiable intentions or not, whether they be defensive, preventive or aggressive. In the light of scholarly viewpoints (such as that of Saint Augustine) and judging by the short and long-term outcomes of hostilities in the history of Middle-earth, an attempt will be made to identify perspectives on the concept of “just war” in Tolkien’s secondary world.

    Cellular-Resolution Population Imaging Reveals Robust Sparse Coding in the Drosophila Mushroom Body

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    Sensory stimuli are represented in the brain by the activity of populations of neurons. In most biological systems, studying population coding is challenging since only a tiny proportion of cells can be recorded simultaneously. Here we used two-photon imaging to record neural activity in the relatively simple Drosophila mushroom body (MB), an area involved in olfactory learning and memory. Using the highly sensitive calcium indicator GCaMP3, we simultaneously monitored the activity of >100 MB neurons in vivo (similar to 5% of the total population). The MB is thought to encode odors in sparse patterns of activity, but the code has yet to be explored either on a population level or with a wide variety of stimuli. We therefore imaged responses to odors chosen to evaluate the robustness of sparse representations. Different odors activated distinct patterns of MB neurons; however, we found no evidence for spatial organization of neurons by either response probability or odor tuning within the cell body layer. The degree of sparseness was consistent across a wide range of stimuli, from monomolecular odors to artificial blends and even complex natural smells. Sparseness was mainly invariant across concentrations, largely because of the influence of recent odor experience. Finally, in contrast to sensory processing in other systems, no response features distinguished natural stimuli from monomolecular odors. Our results indicate that the fundamental feature of odor processing in the MB is to create sparse stimulus representations in a format that facilitates arbitrary associations between odor and punishment or reward

    On Unitary Time Evolution in Gowdy T3T^3 Cosmologies

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    A non-perturbative canonical quantization of Gowdy T3T^3 polarized models carried out recently is considered. This approach profits from the equivalence between the symmetry reduced model and 2+1 gravity coupled to a massless real scalar field. The system is partially gauge fixed and a choice of internal time is performed, for which the true degrees of freedom of the model reduce to a massless free scalar field propagating on a 2-dimensional expanding torus. It is shown that the symplectic transformation that determines the classical dynamics cannot be unitarily implemented on the corresponding Hilbert space of quantum states. The implications of this result for both quantization of fields on curved manifolds and physically relevant questions regarding the initial singularity are discussed.Comment: 16 pages, no figures, latex file; references added, a proof included. Final version to appear in IJMP

    Electrokinetic confinement of axonal growth for dynamically configurable neural networks

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    Axons in the developing nervous system are directed via guidance cues, whose expression varies both spatially and temporally, to create functional neural circuits. Existing methods to create patterns of neural connectivity in vitro use only static geometries, and are unable to dynamically alter the guidance cues imparted on the cells. We introduce the use of AC electrokinetics to dynamically control axonal growth in cultured rat hippocampal neurons. We find that the application of modest voltages at frequencies on the order of 10[superscript 5] Hz can cause developing axons to be stopped adjacent to the electrodes while axons away from the electric fields exhibit uninhibited growth. By switching electrodes on or off, we can reversibly inhibit or permit axon passage across the electrodes. Our models suggest that dielectrophoresis is the causative AC electrokinetic effect. We make use of our dynamic control over axon elongation to create an axon-diode via an axon-lock system that consists of a pair of electrode ‘gates’ that either permit or prevent axons from passing through. Finally, we developed a neural circuit consisting of three populations of neurons, separated by three axon-locks to demonstrate the assembly of a functional, engineered neural network. Action potential recordings demonstrate that the AC electrokinetic effect does not harm axons, and Ca[superscript 2+] imaging demonstrated the unidirectional nature of the synaptic connections. AC electrokinetic confinement of axonal growth has potential for creating configurable, directional neural networks.National Institutes of Health (U.S.) (R01 EUREKA Award R01-NS066352

    Oblique internal hydraulic jumps at a stratified estuary mouth

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    Author Posting. © American Meteorological Society, 2017. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 47 (2017): 85-100, doi:10.1175/JPO-D-15-0234.1.Observations and analyses of two tidally recurring, oblique, internal hydraulic jumps at a stratified estuary mouth (Columbia River, Oregon/Washington) are presented. These hydraulic features have not previously been studied due to the challenges of both horizontally resolving the sharp gradients and temporally resolving their evolution in numerical models and traditional observation platforms. The jumps, both of which recurred during ebb, formed adjacent to two engineered lateral channel constrictions and were identified in marine radar image time series. Jump occurrence was corroborated by (i) a collocated sharp gradient in the surface currents measured via airborne along-track interferometric synthetic aperture radar and (ii) the transition from supercritical to subcritical flow in the cross-jump direction via shipborne velocity and density measurements. Using a two-layer approximation, observed jump angles at both lateral constrictions are shown to lie within the theoretical bounds given by the critical internal long-wave (Froude) angle and the arrested maximum-amplitude internal bore angle, respectively. Also, intratidal and intertidal variability of the jump angles are shown to be consistent with that expected from the two-layer model, applied to varying stratification and current speed over a range of tidal and river discharge conditions. Intratidal variability of the upchannel jump angle is similar under all observed conditions, whereas the downchannel jump angle shows an additional association with stratification and ebb velocity during the low discharge periods. The observations additionally indicate that the upchannel jump achieves a stable position that is collocated with a similarly oblique bathymetric slope.We acknowledge the financial support of the Office of Naval Research under Awards N00014-10-1-0932 and N00014-13-1-0364.2017-07-0

    Index of pretreatment intensity predicts outcome of high-dose chemotherapy and autologous progenitor cell transplantation in chemosensitive relapse of Hodgkin's disease

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    Purpose To identify prognostic factors in patients with chemosensitive relapsed Hodgkin's disease treated by high-dose chemotherapy with autologous progenitor cell transplantation (HDC) and to compare the duration of treatment-free remission prior to HDC with the progression-free survival after HDC in individual patients. Patients and methods Forty-five consecutive patients were analyzed retrospectively. We devised an index of pretreatment intensity (IPTI) based number of different chemo- and radio-therapy regimens given between diagnosis and HDC and on the duration of disease. Results With a median follow-up of 47 months the post-transplant event-free survival (EFS) was 44% and the overall survival. (OAS) was 62% at four years. The IPTI allowed to discriminate between a low and a high-risk group with a four-year post-transplant EFS of 66% and 11% and a OAS of 87% and 28%, respectively (P = 0.0001). Of the 39 patients with sufficient follow-up after HDC, post-transplant EFS lasted on average ≄ 18.5 months longer than the pretransplant treatment-free remission. Conclusions HDC with the CBV regimen confers significant benefit to patients with chemosensitive relapsed Hodgkin's disease. The IPTI may help to select patients with a good response to HDC and to identify poor prognosis patients suitable for experimental protocols or palliative care onl

    Vacuum distillation/vapor filtration water recovery

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    The development and evaluation of a vacuum distillation/vapor filtration (VD/VF) water recovery system are considered. As a functional model, the system converts urine and condensates waste water from six men to potable water on a steady-state basis. The system is designed for 180-day operating durations and for function on the ground, on zero-g aircraft, and in orbit. Preparatory tasks are summarized for conducting low gravity tests of a vacuum distillation/vapor filtration system for recovering water from urine
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