Laser Doppler Velocimetry for Joint Measurements of Acoustic and Mean Flow Velocities : LMS-based Algorithm and CRB Calculation

This paper presents a least mean square (LMS) algorithm for the joint estimation of acoustic and mean flow velocities from laser doppler velocimetry (LDV) measurements. The usual algorithms used for measuring with LDV purely acoustic velocity or mean flow velocity may not be used when the acoustic field is disturbed by a mean flow component. The LMS-based algorithm allows accurate estimations of both acoustic and mean flow velocities. The Cram\'er-Rao bound (CRB) of the associated problem is determined. The variance of the estimators of both acoustic and mean flow velocities is also given. Simulation results of this algorithm are compared with the CRB and the comparison leads to validate this estimator

Quantum memory for light: large efficiency at telecom wavelength

We implement the ROSE protocol in an erbium doped solid, compatible with the telecom range. The ROSE scheme is an adaptation of the standard 2-pulse photon echo to make it suitable for a quantum memory. We observe an efficiency of 40% in a forward direction by using specific orientations of the light polarizations, magnetic field and crystal axes

X-ray structures of dinuclear copper(I) and polynuclear copper(II) complexes with the 2,4-bis(cyanamido)cyclobutane-1,3-dione dianion

From the 2,4-bis(cyanamido)cyclobutane-1,3-dione dianion (2,4-NCNsq2−), two copper complexes [Cu2(PPh3)4(PhCN)2(μ-2,4-NCNsq)] · PhCN (1) and [Cu(dien)(μ-2,4-NCNsq) · H2O]n (2) have been synthesized and characterized by IR and electronic absorption spectroscopies. Their structures have been determined by X-ray crystallography. Complex 1 is a dinuclear copper(I) compound with a 2,4-NCNsq2− ligand bridging two copper atoms through the nitrile nitrogen atoms. Complex 2 appears as a 3D network constituted of copper(II) atoms bridged by 2,4-NCNsq2− dianions. This complex presents an unexpected coordination mode of the bis(cyanamido) ligands which are both coordinated via the nitrile functions and via the amido nitrogen atoms of the NCN groups

Selective optical addressing of nuclear spins through superhyperfine interaction in rare-earth doped solids

In Er$^{3+}$:Y$_2$SiO$_5$, we demonstrate the selective optical addressing of the $^{89}$Y$^{3+}$ nuclear spins through their superhyperfine coupling with the Er$^{3+}$ electronic spins possessing large Land\'e $g$-factors. We experimentally probe the electron-nuclear spin mixing with photon echo techniques and validate our model. The site-selective optical addressing of the Y$^{3+}$ nuclear spins is designed by adjusting the magnetic field strength and orientation. This constitutes an important step towards the realization of long-lived solid-state qubits optically addressed by telecom photons.Comment: 5 pages, 4 figures, supplementary material (3 pages

State aid and the financing of public services: A comment on the Altmark judgment of the Court of Justice

On 24 July 2003, the European Court of Justice handed down its judgment in the Altmark case, ending the controversy surrounding the application of the EC state aid control regime to compensation granted to undertakings in consideration for public service obligations imposed on them

Salaire des fonctionnaires et vie privée

Le présent article s'intéresse à la question que soulève la compatibilité des dispositions de la Loi sur l'accès aux documents des organismes publics et sur la protection des renseignements personnels qui, sur demande d'une personne, imposent la divulgation des salaires des hauts dirigeants des organismes publics et des échelles de salaire des autres fonctionnaires, avec les exigences des chartes des droits en matière de protection de la vie privée des individus. Il explique d'abord le fondement constitutionnel de la règle traditionnelle qui a amené annuellement la divulgation dans les Comptes publics des salaires des fonctionnaires et décrit la pratique observée à cet égard dans ces documents depuis 1867. Il décrit ensuite l'effet qu'a eu l'arrivée de la loi mentionnée plus haut et qui donne un caractère public aux renseignements des organismes publics en cette matière. Il s'attarde aussi, à partir d'une décision rendue récemment par la Commission d'accès à l'information, sur la question de savoir si le droit à la vie privée conféré par les chartes n'est pas mis en péril par ces nouvelles dispositions imposant la transparence aux organismes publics. Cette décision est ensuite analysée et commentée, notamment à partir de décisions américaines rendues sur le même sujet et de la public service vision qui en découle.This article addresses the question raised by the compatibility of provisions under An Act respecting Access to documents held by public bodies and the Protection of personal information which, upon the request of a citizen, requires the disclosure of salaries of ranking officials in public bodies and the salary scales of other civil servants, with those of the charter of rights regarding the protection of individuals' privacy. It initially explains the constitutional basis of the traditional rule which annually led to the disclosure in the Public Accounts of civil servants’ salaries and describes the practice observed in this respect in these documents since 1867. It then goes on to describe the effect that the aforementioned act has had and the public character given to information from public bodies in such matters. On the basis of a decision recently handed down by the Commission on Access to Information, the article also dwells upon the question of whether the right to privacy granted under the charters is not endangered by these new provisions requiring transparency in public bodies. This decision is then analyzed and commented, especially based on American decisions bearing on the same subject and the Public Service Vision issuing therefrom

An investigation of data compression techniques for hyperspectral core imager data

We investigate algorithms for tractable analysis of real hyperspectral image data from core samples provided by AngloGold Ashanti. In particular, we investigate feature extraction, non-linear dimension reduction using diffusion maps and wavelet approximation methods on our data

Optical memory bandwidth and multiplexing capacity in the erbium telecommunication window

We study the bandwidth and multiplexing capacity of an erbium-doped optical memory for quantum storage purposes. We concentrate on the protocol ROSE (Revival of a Silenced Echo) because it has the largest potential multiplexing capacity. Our analysis is applicable to other protocols that involve strong optical excitation. We show that the memory performance is limited by instantaneous spectral diffusion and we describe how this effect can be minimised to achieve optimal performance