L’eau courante et le consommateur : comprendre les défis pour le gestionnaire de services au regard de l'expérience de Nantes Métropole

Le rapport de l'individu à l'eau, du fait de la prise de conscience écologique, a été profondément bouleversé. C'est ainsi tout un réseau qui doit revoir son agencement et remettre en question les normes qui le régissaient. Les gestionnaires des services de l'eau sont donc confrontés à de nouveaux défis : ils doivent à la fois tendre vers un plus grand respect de l'environnement et y inciter leurs usagers tout en instaurant une relation de confiance avec eux, sur des bases nouvelles. À travers l'exemple de Nantes Métropole, les multiples facettes de ce nouvel âge de la consommation d'eau sont mises en lumière

Optimal Targeting Regimes and Instrument Rules in the Basic New Keynesian Model

In the first chapter, the objective is to measure the value of commitment in executing monetary policies in the context of the New Keynesian model and with value that is represented by the standard quadratic welfare function containing weighted output gap and inflation variances. It is found that there is a substantial potential for improvement of welfare under commitment, but this depends on some key parameters in the model. The range of parameter calibrations most often found in the literature, however, suggests the improvements will be large. We then consider specific monetary policies akin to Taylor rules. From the optimality conditions we derive a Taylor-type rule that meets the optimal path conditions exactly. Further, we derive a form which is actually guaranteed to produce a determinate outcome the model\u27s endogenous variables and welfare. The first chapter outlined the baseline of the New Keynesian model and provided an analytical solution to measure welfare for discretion, pre-commitment and global policies. The analysis was done under the presumption that policy makers seek to maximize the standard social welfare. The second chapter measures the benefit of \u27delegating\u27 authority to the central bank to maximize other welfare functions. It is assumed that the public is convinced the central bank will maximize this particular welfare on the long run. These alternative approaches are referred as speed limit, price level targeting, and nominal income growth targeting. The chapter shows to what extent some of those approaches may provide higher welfare than when adopting the global target and how it depends on the parameters. The chapter shows also that another alternative would be to including volatility of interest rate in the welfare function. While this strategy would not often provide a higher welfare than the global target, it has the advantage of making the volatility of interest rate low, which could be beneficial when trying to avoid the lower bound issue. The third chapter investigates on how to implement the policy that will replicate the optimal paths found in previous chapter for each of the approaches. In the New Keynesian model, the most common procedure that central banks use is the Taylor rule which links the nominal interest rate with inflation and output gap. However, this raises questions about determinacy. This chapter demonstrates that when using a money rule, one which uses money as the instrument, determinacy constraints are not very different from the ones encountered with an interest rate rule. In the same vein, the adoption of a Wicksellian rule (the interest rate or money responds to the price level and output gap) does not make it easier to find a stable and unique solution

Spectral wings of the fiber supercontinuum and the dark-bright soliton interaction

We present experimental and numerical data on the supercontinuum generation in an optical fiber pumped in the normal dispersion range where the seeded dark and the spontaneously generated bright solitons contribute to the spectral broadening. We report the dispersive radiation arising from the interaction of the bright and dark solitons. This radiation consists of the two weak dispersing pulses that continuously shift their frequencies and shape the short and long wavelength wings of the supercontinuum spectrum.Comment: supercontinuum, soliton, fiber; 6 page

Longitudinal soliton tunneling in optical fiber

International audienceWe report the observation of the longitudinal soliton tunneling effect in axially-varying optical fibers. A fundamental soliton, initially propagating in the anomalous dispersion region of a fiber, can pass through a normal dispersion barrier without being substantially affected. We perform experimental studies by means of spectral and temporal characterizations that show the evidence of longitudinal soliton tunneling process. Our results are well supported by numerical simulations using the generalized nonlinear Schrödinger equation

Emission of dispersive waves from a train of dark solitons in optical fibers

International audienceWe report the experimental observation of multiple dis-persive waves emitted in the anomalous dispersion region of an optical fiber from a train of dark solitons. Each individual dispersive wave can be associated to one particular dark soliton of the train, using phase-matching arguments involving higher-order dispersion and soliton velocity. For a large number of dark solitons (> 10), we observe the formation of a continuum associated with the efficient emission of disper-sive waves

Grayness-dependent emission of dispersive waves from dark solitons in optical fibers

International audienceWe report the experimental observation of dispersive wave emission from gray solitons propagating in the normal dispersion region of an optical fiber. Besides observing for the first time the emission of a disper-sive wave from an isolated dark soliton, we show that the dispersive wave frequency and amplitude strongly depends on soliton grayness. This process can be explained by the higher-order dispersion contribution into the phase-matching condition and the grayness of the soliton. Numerical simulations and theoretical predictions are in good agreement with the experiments

Collision between a dark soliton and a linear wave in an optical fiber

We report an experimental observation of the collision between a linear wave propagating in the anomalous dispersion region of an optical fiber and a dark soliton located in the normal dispersion region. This interaction results in the emission of a new frequency component whose wavelength can be predicted using phase-matching arguments. The measured efficiency of this process shows a strong dependency with the soliton grayness and the linear wave wavelength, and is in a good agreement with theory and numerical simulations.Comment: 10 pages, 6 figures, 1 annex

Metallic and nonmetallic double perovskites: A case study of A2_2FeReO6_6 (A= Ca, Sr, Ba)

We have investigated the structure and electronic properties of ferrimagnetic double perovskites, A2FeReO6 (A= Ca, Sr, Ba). The A=Ba phase is cubic (Fm3m) and metallic, while the A=Ca phase is monoclinic (P21/n) and nonmetallic. 57Fe Mossbauer spectroscopy shows that iron is present mainly in the high-spin (S=5/2) Fe3+ state in the Ca compound, while it occurs in an intermediate state between high-spin Fe2+ and Fe3+ in the Ba compound. It is argued that a direct Re t2g - Re t2g interaction is the main cause for the metallic character of the Ba compound; the high covalency of Ca-O bonds and the monoclinic distortion (which lifts the degeneracy of t2g states) seem to disrupt the Re-Re interaction in the case of the Ca compound, making it non-metallic for the same electron count.Comment: 1 eps fil

Une église de briques et de broc

Ce billet parle de l'utilisation de l'archéologie pour mon sujet. L'église de l'évêque du Pégou : Paul de Nérini est une personne essentielle dans ma recherche (comme je l'ai rapidement  présenté dans le billet Mon sujet). Je le place dans le cercle des protagonistes directs, ceux qui ont été en contact avec Sieur de Bruno. L'évêque du Pégou a été son intermédiaire sur place, servant à la fois de traducteur, de soutien, de guide aussi bien pour se déplacer dans le royaume que dans la socié..

Mon sujet

Ce billet présente mon sujet de mémoire: "Le 14 juillet 1751 étant mouillé devant la rade de Siriam avec le vaisseau de la Compagnie la Favorite, envoyé par M. Dupleix, [...], le prince de Siriam m'a envoyé un chef de la Roudaye avec un interprette pour me demander d'où venoit le vaisseau, quel sujet nous amenoit dans ce pays, [...]"1  Au milieu du XVIIIe siècle, un Français nommé Sieur de Bruno (ou Bruneau) est arrivé dans l'actuelle Birmanie, dans ce qui était le royaume de Pégou. De sa mis..