Characterization of digital dispersive spectrometers by low coherence interferometry

We propose a procedure to determine the spectral response of digital dispersive spectrometers without previous knowledge of any parameter of the system. The method consists of applying the Fourier transform spectroscopy technique to each pixel of the detection plane, a CCD camera, to obtain its individual spectral response. From this simple procedure, the system-point spread function and the effect of the finite pixel width are taken into account giving rise to a response matrix that fully characterizes the spectrometer. Using the response matrix information we find the resolving power of a given spectrometer, predict in advance its response to any virtual input spectrum and improve numerically the spectrometer's resolution. We consider that the presented approach could be useful in most spectroscopic branches such as in computational spectroscopy, optical coherence tomography, hyperspectral imaging, spectral interferometry and analytical chemistry, among others.Fil: Martínez Matos, Ó.. Universidad Complutense de Madrid; EspañaFil: Rickenstorff, C.. Universidad Complutense de Madrid; EspañaFil: Zamora, S.. Universidad Complutense de Madrid; EspañaFil: Izquierdo, J. G.. Universidad Complutense de Madrid; EspañaFil: Vaveliuk, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Ópticas. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones Ópticas. Universidad Nacional de La Plata. Centro de Investigaciones Ópticas; Argentin

Kink fluctuation asymptotics and zero modes

In this paper we propose a refinement of the heat kernel/zeta function treatment of kink quantum fluctuations in scalar field theory, further analyzing the existence and implications of a zero energy fluctuation mode. Improved understanding of the interplay between zero modes and the kink heat kernel expansion delivers asymptotic estimations of one-loop kink mass shifts with remarkably higher precision than previously obtained by means of the standard Gilkey-DeWitt heat kernel expansion.Comment: 21 pages, 8 figures, to be published in The European Physical Journal

Price, Wage and Employment Response to Shocks: Evidence from the WDN Survey

This paper analyses information from survey data collected in the framework of the Eurosystem's Wage Dynamics Network (WDN) on patterns of firm-level adjustment to shocks. We document that the relative intensity and the character of price vs. cost and wage vs. employment adjustments in response to cost-push shocks depend - in theoretically sensible ways - on the intensity of competition in firms' product markets, on the importance of collective wage bargaining and on other structural and institutional features of firms and of their environment. Focusing on the pass-through of cost shocks to prices, our results suggest that the pass-through is lower in highly competitive firms. Furthermore, a high degree of employment protection and collective wage agreements tend to make this pass-through stronger.Wage bargaining, Labour-market institutions, Survey data, European Union.

On domain walls in a Ginzburg-Landau non-linear S^2-sigma model

The domain wall solutions of a Ginzburg-Landau non-linear $S^2$-sigma hybrid model are unveiled. There are three types of basic topological walls and two types of degenerate families of composite - one topological, the other non-topological- walls. The domain wall solutions are identified as the finite action trajectories (in infinite time) of a related mechanical system that is Hamilton-Jacobi separable in sphero-conical coordinates. The physical and mathematical features of these domain walls are thoroughly discussed.Comment: 26 pages, 18 figure

Femtosecond multichannel photodissociation dynamics of CH3I from the A band by velocity map imaging

4 pages, 3 figures, 1 table.The reaction times of several well-defined channels of the C–I bond rupture of methyl iodide from the A band, which involves nonadiabatic dynamics yielding ground state I(2P3/2) and spin-orbit excited I*(2P1/2) and ground and vibrationally excited CH3 fragments, have been measured by a combination of a femtosecond laser pump-probe scheme and velocity map imaging techniques using resonant detection of ground state CH3 fragments. The reaction times found for the different channels studied are directly related with the nonadiabatic nature of this multidimensional photodissociation reaction.Two of the authors (J. G. I. and J. D.) gratefully acknowledge financial support from the FPI program and the CSIC-Unidades Asociadas program, respectively, of the Spanish Ministry of Education and Science (MEC). This work has been financed by the Spanish MEC through Grant No. CTQ2005-08493- C02-01.Peer reviewe

Advanced content-based semantic scene analysis and information retrieval: the SCHEMA project

The aim of the SCHEMA Network of Excellence is to bring together a critical mass of universities, research centers, industrial partners and end users, in order to design a reference system for content-based semantic scene analysis, interpretation and understanding. Relevant research areas include: content-based multimedia analysis and automatic annotation of semantic multimedia content, combined textual and multimedia information retrieval, semantic -web, MPEG-7 and MPEG-21 standards, user interfaces and human factors. In this paper, recent advances in content-based analysis, indexing and retrieval of digital media within the SCHEMA Network are presented. These advances will be integrated in the SCHEMA module-based, expandable reference system

BPS-Saturated Bound States of Tilted P-Branes in Type II String Theory

We found BPS-saturated solutions of M-theory and Type II string theory which correspond to (non-marginally) bound states of p-branes intersecting at angles different from pi/2. These solutions are obtained by starting with a BPS marginally bound (orthogonally) intersecting configurations of two p-branes (e.g, two four-branes of Type II string theory), performing a boost transformation at an angle with respect to the world-volume of the configuration, performing T-duality transformation along the boost-direction, S-duality transformation, and T- transformations along the direction perpendicular to the boost transformation. The resulting configuration is non-marginally bound BPS-saturated solution whose static metric possesses the off-diagonal term which cannot be removed by a coordinate transformation, and thus signifies an angle (different from pi/2) between the resulting intersecting p-branes. Additional new p-branes are bound to this configuration, in order to ensure the stability of such a static, tilted configuration.Comment: 11 pages, Latex with two postscript figures, minor corrections, version to appear in Phys. Rev.

Killing spinors, the adS black hole and I(ISO(2,1)) gravity

We construct a supersymmetric extension of the $I\big(ISO(2,1)\big)$ Chern-Simons gravity and show that certain particle-like solutions and the adS black-hole solution of this theory are supersymmetric.Comment: 12 pages, uses phyzz

District metered area design through multicriteria and multiobjective optimization

The design of district metered areas (DMA) in potable water supply systems is of paramount importance for water utilities to properly manage their systems. Concomitant to their main objective, namely, to deliver quality water to consumers, the benefits include leakage reduction and prompt reaction in cases of natural or malicious contamination events. Given the structure of a water distribution network (WDN), graph theory is the basis for DMA design, and clustering algorithms can be applied to perform the partitioning. However, such sectorization entails a number of network modifications (installing cut-off valves and metering and control devices) involving costs and operation changes, which have to be carefully studied and optimized. Given the complexity of WDNs, optimization is usually performed using metaheuristic algorithms. In turn, optimization may be single or multiple-objective. In this last case, a large number of solutions, frequently integrating the Pareto front, may be produced. The decision maker has eventually to choose one among them, what may be tough task. Multicriteria decision methods may be applied to support this last step of the decision-making process. In this paper, DMA design is addressed by (i) proposing a modified k-means algorithm for partitioning, (ii) using a multiobjective particle swarm optimization to suitably place partitioning devices, (iii) using fuzzy analytic hierarchy process (FAHP) to weight the four objective functions considered, and (iv) using technique for order of preference by similarity to ideal solution (TOPSIS) to rank the Pareto solutions to support the decision. This joint approach is applied in a case of a well-known WDN of the literature, and the results are discussed