19,609 research outputs found

    Synchrotron radiation: science & applications

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    This general talk is devoted to briefly introduce the main uses and applications of synchrotron radiation. An initial introduction will be dedicated to describe a synchrotron as a Large Facility devoted to produce photons that will be used to carry out excellent science. The five outstanding main characteristics of synchrotron radiation are: i) High brilliance and collimation ii) Wavelength tunability iii) Beamsize tunability iv) Defined polarization v) Time structure vi) (Partial) coherence These properties will be illustrated through selected examples ranging from biomedicine (f.i. determination of the crystal structure of macromolecules from tiny crystals or cryo- nano tomography of individual cells by soft X-ray transmission microscopy) to materials science (f.i. experiments of powder diffraction of materials under high pressure in diamond-anvil-cells), from cultural heritage (f.i. the study of degradation of pigments in paints by X-ray absorption spectroscopy) to cements (f.i. the hydration chemistry of eco-cements followed by in-situ powder diffraction), and from basic research on magnetic materials (f.i. ferromagnets where the magnetism of individual metal transition elements are selectively followed by X-ray Magnetic Circular Dicroism) to industrial applications on chocolate (f.i. small X-ray scattering as function of temperature of the polymorphs of cacao).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    A track-before-detect labelled multi-Bernoulli particle filter with label switching

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    This paper presents a multitarget tracking particle filter (PF) for general track-before-detect measurement models. The PF is presented in the random finite set framework and uses a labelled multi-Bernoulli approximation. We also present a label switching improvement algorithm based on Markov chain Monte Carlo that is expected to increase filter performance if targets get in close proximity for a sufficiently long time. The PF is tested in two challenging numerical examples.Comment: Accepted for publication in IEEE Transactions on Aerospace and Electronic System

    Synchrotron Radiation and ALBA Facility

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    ALBA synchrotron light source (www.cells.es) is the largest Spanish research infrastructure that started full operation of its first 7 beamlines on February 2013. I will divide the talk in three parts: i) the general description of the facility; ii) the eight beamlines currently operating at ALBA; and iii) the three beamlines which are under design/construction. I will start with a very brief description of the facility including the construction costs, staff structure and general parameters. Then, I will briefly describe our three accelerators: LINAC, booster and the store ring. Some characteristic parameters will be described. To finish this part, I will touch the three main magnetic technologies to produce X-rays from the ALBA electron beam. Secondly, I will concisely describe the eight beamlines with their main application fields. A photography of our experimental hall with a Table displaying the current beamlines is shown just below. The ways to use ALBA including the call-for-proposals will be described. The proposals (both national and internationals) are judged by an international panel on the basis of scientific excellence. Finally, I will briefly explain the current construction stage of the new beamlines.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Selecting a pooling equilibrium in a signaling game with a bounded set of signals

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    In this paper, we study a general class of monotone signaling games, in which the support of the signal is limited or the cost of the signal is sufficiently low and as a result, there are multiple pooling equilibria. In those games, when we relax the usual single-crossing condition, the typical restrictions on the out-of-equilibrium beliefs suggested by previous literature cannot discard any of the equilibria obtained. For this reason, we develop a new refinement called the most profitable deviator, which will be useful to select a unique equilibrium in those games. Additionally, when the standard single-crossing condition is satisfied, our criterion also chooses a unique equilibrium, which is the same as that selected by previous literature.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Powder diffraction at ALBA synchrotron

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    This talk is devoted to explain the uses of powder diffraction at MSPD (material science and powder diffraction) of ALBA synchrotron light source. General characteristics of the beamline are: Station 1 - High Pressure Diffraction on powders with diamond anvil cell (DAC) and CCD detector. Microdiffraction; and Station 2 - High Resolution Powder Diffraction with Multicrystal- and Silicon-Strip detector. Energy Range: 8-50keV; Typical beam size: 4x1mm; all typical sample geometries possible: capillary, reflection and flat sample in transmission. Initially the setups are described in detail both in the optics hutch and in the experimental hutch. In the high-pressure end station, we can highlight: i) sample alignment semi-automatic; ii) data acquisition and reduction integrated within the beamline control system; iii) online pressure calibration system operational and several upgrades which are under commissioning: i) system for Membrane DAC, Automatic Drive System (change the pressure from outside the hutch); ii) Gas Membrane kit for Almax-Boehler DAC cell (from screw-driven to gas membrane driven); iii) low temperature cryostat and high temperature DAC cell projects are on-going. In the high resolution powder diffraction end station, we can highlight: i) a diffractometer with 3 concentric rotary stages (for two detectors); ii) one very high resolution detector MAD26 (10 – 50KeV), devoted to high resolution ~0.005° [13 channels with 1.5 deg pitch, Si111 Bragg crystals, YAP scintillator + PMT]; iii) MythenII (8 – 30 keV) for fast acquisitions [6 modules that cover 40 deg 0.005 pitch angle, with millisecond resolution]; iv) Temperature range 80 – 900K; v) Eulerian Cradle optional. Then, the main applications will be dealt with based on examples that expands from structure solution of zeolites to the in-situ studies of perovskite catalyst under H2 atmosphere at high temperatures. Total scattering (pair distribution function analysis) will also be presented. The high-pressure studies will be exemplified by studies of materials in DAC.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Powder diffraction at ALBA synchrotron

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    This talk is devoted to explain the uses of powder diffraction at MSPD (material science and powder diffraction) of ALBA synchrotron light source. General characteristics of the beamline are: Station 1 - High Pressure Diffraction on powders with diamond anvil cell (DAC) and CCD detector. Microdiffraction; and Station 2 - High Resolution Powder Diffraction with Multicrystal- and Silicon-Strip detector. Energy Range: 8-50keV; Typical beam size: 4x1mm; all typical sample geometries possible: capillary, reflection and flat sample in transmission. Initially the setups are described in detail both in the optics hutch and in the experimental hutch. In the high-pressure end station, we can highlight: i) sample alignment semi-automatic; ii) data acquisition and reduction integrated within the beamline control system; iii) online pressure calibration system operational and several upgrades which are under commissioning: i) system for Membrane DAC, Automatic Drive System (change the pressure from outside the hutch); ii) Gas Membrane kit for Almax-Boehler DAC cell (from screw-driven to gas membrane driven); iii) low temperature cryostat and high temperature DAC cell projects are on-going. In the high resolution powder diffraction end station, we can highlight: i) a diffractometer with 3 concentric rotary stages (for two detectors); ii) one very high resolution detector MAD26 (10 – 50KeV), devoted to high resolution ~0.005° [13 channels with 1.5 deg pitch, Si111 Bragg crystals, YAP scintillator + PMT]; iii) MythenII (8 – 30 keV) for fast acquisitions [6 modules that cover 40 deg 0.005 pitch angle, with millisecond resolution]; iv) Temperature range 80 – 900K; v) Eulerian Cradle optional. Then, the main applications will be dealt with based on examples that expands from structure solution of zeolites to the in-situ studies of perovskite catalyst under H2 atmosphere at high temperatures. The high-pressure studies will be exemplified by studies of materials in DAC.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    The origin principle and the welfare gains from indirect tax harmonization

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    The purpose of this paper is to establish a parallelism between the analyses in Keen (1987,1989.a) referred to indirect tax harmonization when taxes are levied according to the destination principle and its counterpart when taxes are imposed on an origin basis. Using a simple two-country model of international trade it is argued that indirect tax harmonization under the origin principle, considered as a movement of domestic taxes towards an appropriately designed "average" tax structure, is potentially Pareto improving, in the sense that the welfare of a given country can be increased provided that the other country's welfare is kept unchanged with the aid of an international transfer. In the same vein, it is shown that if the initial position is a Nash equilibrium, there are situations under which the above-mentioned reform may generate an actual Pareto improvement, so that both countries improve their welfare without any need for a compensating international transfer. As stated above, the definitive system will be a mixed one, so that the pure origin case is not the most realistic framework from a policy point of view. However, it may be useful in yielding indications that, coupled with the results that have been obtained under the destination principle, provide insights on the effects of the definitive system

    ALBA Synchrotron Light Source

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    ALBA synchrotron light source (www.cells.es) is the largest Spanish research infrastructure that started full operation of its first 7 beamlines on February 2013. I will divide the talk in three parts: i) the general description of the facility; ii) the seven bealines and current ALBA usage; and iii) the future ALBA beamlines and possibilities for collaboration. Two beamlines (phase-II) are under construction and six proposals for new beamlines (phase-III) have been positively evaluated by ALBA-SAC (Scientific Advisory Committee). I will start with a very brief description of the facility including the construction costs, staff structure and general parameters. Then, I will briefly describe our three accelerators: LINAC, booster and the store ring. Some characteristic parameters will be described. To finish this part, I will touch the three main magnetic technologies to produce X-rays from the ALBA electron beam. Secondly, I will concisely describe the seven beamlines with their main application fields. A photography of our experimental hall with a Table displaying the seven current beamlines is shown just below. The ways to use ALBA including the call-for-proposals will be described. The proposals (both national and internationals) are judged by an international panel on the basis of scientific excellence. Thirdly, I will briefly explain the current phase II with the construction of two beamlines, infrared microspectroscopy and angular-resolved photoemission. Finally, I will then present the plans for the phase-III beamlines as well as examples of ways to collaborate with ALBA synchrotron.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Does illegal immigration empower rightist parties?

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    The main goal of this paper is to analyze the political outcome in countries where the relevant issue in elections is the control of immigration. In particular we explore the consequences on the political outcome of the fact that parties are either ideological or opportunistic with respect to this issue. In order to do that we use a simple two-party political competition model in which the issues over which parties take positions are the level of border enforcement and the way it has to be financed. We show that an ideological rather than a pure opportunistic behavior gives parties an advantage to win the election. This result may help us to understand the recent success of anti-immigrant and rightist parties in several countries.Illegal immigration, ideological parties, unskilled and skilled.
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