Characterisation and calibration of a scintillating fibre detector with > 4000 multi-anode photomultiplier channels

In the Kaos spectrometer at the Mainz Microtron a high-resolution coordinate detector for high-energy particles is operated. It consists of scintillating fibres with diameters of 4000 multi-anode photomultiplier channels. It is one of the most modern focal-plane detectors for magnetic spectrometers world-wide. To correct variations in the detection efficiency, caused by the different gains and the different optical transmittances, a fully automated off-line calibration procedure has been developed. The process includes the positioning of a radioisotope source alongside the detector plane and the automated acquisition and analysis of the detector signals. It was possible to characterise and calibrate each individual fibre channel with a low degree of human interaction.Comment: Nucl. Instrum. Meth. A (2012

Mineralogía de las arcillas en suelos y alteraciones sobre materiales graníticos de Galicia

[Resumen] Se realiza un estudio de la naturaleza de la fracción arcilla en suelos y capas de alteración de.rocas graníticas de Galicia (58 perfiles) encontrando un predominio de minerales propios de "sistemas abiertos" como filosilicatos 1:1 y gibbsita acompañados .de minerales de tipo mica más o menos degradados. Las esmectitas son muy poco abundantes y en general no parecen formarse en procesos edáficos. Dentro del perfil se diferencian dos zonas, una de escasa actividad de la materia orgánica en la que las plagioclasas son los minerales más lábiles, originándose gibbsita por mecanismos de hidrólisis o acidolisis moderada. Otra en las capas superficiales con un mayor ataque a los minerales de tipo mica por mecanismos acidolíticos o de ácido-complexolisis moderada[Abstract] The nature of the clay fraction of saprolites and soils developed on granitic rocks of Galicia (58 profiles) is studied. It is found a predominance of minerais typical of "open systems" like hyllosilicats 1: 1 and gibbsite, acompamed by mica type minerals with different levels of degradation . The smectits are rare and its origin, sems to have no relation with the processes of soil formation. In the profile two zones can be differentiated, at one of them, with very low activity of organic matter, the plagioclases are the most labile minerals '1' and the dominant process is the formation of gibbsite by means of mechanisms of hydrolysis or moderate acidolysis · The upper zone, with high activity of organic matter, is characterized by a stronger attack to the mica type minerals by acidolytic or oderate acido-coplexolytic mechanisms

Evento anual de las Sociedades Científicas de la Unión Nacional de Juristas de Cuba : La vía de lesividad administrativa: utopía vs. realidad en el ordenamiento jurídico cubano

Cuando se piensa en el actuar de la Administración Pública la referencia más inmediata que acude es la relacionada el poder de una persona cuyas decisiones emergen con la presunción de validez que determina, en el destinatario del acto, la obligatoriedad de su cumplimiento, previo, incluso, a cualquier reclamación. De tal manera se alza la Administración Pública como un sujeto tan intenso que no precisa demostrar que suxs declaraciones de voluntad, deseo, conocimiento o juicio (usando los términos con que describiera ZANNOBINI2 al acto administrativo) son menos que obligatorias. Por supuesto, la percepción del ejercicio de potestad que subyace en su nacimiento, contribuye a esta concepción; así como otros muchos elementos heredados de aquella Administración decimonónica y omnímoda. Pese a ello, el Derecho Público contemporáneo, y sus constantes mutaciones, inclina el eje hacia el fortalecimiento del interés público representado y gestionado por la Administración, y hacia la figura de un administrado cada vez menos pasivo en sus relaciones con el sujeto administrativo.Facultad de Ciencias Jurídicas y Sociale

Comparisons in Performance of Electromagnet and Permanent-Magnet Cylindrical Hall-Effect Thrusters

Three different low-power cylindrical Hall thrusters, which more readily lend themselves to miniaturization and low-power operation than a conventional (annular) Hall thruster, are compared to evaluate the propulsive performance of each. One thruster uses electromagnet coils to produce the magnetic field within the discharge channel while the others use permanent magnets, promising power reduction relative to the electromagnet thruster. A magnetic screen is added to the permanent magnet thruster to improve performance by keeping the magnetic field from expanding into space beyond the exit of the thruster. The combined dataset spans a power range from 50-350 W. The thrust levels over this range were 1.3-7.3 mN, with thruster efficiencies and specific impulses spanning 3.5-28.7% and 400-1940 s, respectively. The efficiency is generally higher for the permanent magnet thruster with the magnetic screen, while That thruster s specific impulse as a function of discharge voltage is comparable to the electromagnet thruster

Dominance of the planktonic diatom Thalassiosira minima in recent summers in the Bahia Blanca Estuary, Argentina

The diatom Thalassiosira minima was first recorded in the Baha Blanca Estuary in 1992. In 19921993 it exhibited a broad seasonal occurrence. A recent survey (20062007) showed a seasonal appearance restricted mainly to summer together with a greater relative abundance within the phytoplankton. A close connection was found with warmer, more saline and highly turbid conditions experienced in recent summers in the estuary. Whether these changes will impact the estuary trophic dynamics remains an open question

ELLIPTIC CURVE CRYPTOGRAPHY. JAVA PLATFORM IMPLEMENTATIONS

Abstract: Elliptic Curve Cryptography (ECC) is one of the most interesting systems for protecting sensitive information nowadays. The latest versions of the Java Platform include classes and interfaces making ECC available to programmers, but due to the nature of Java it is still necessary to employ additional third party packages in order to use cryptographic operations and procedures related to ECC. In the present work, an extensive review of the most important ECC implementations in Java is presented

Recoil polarization and beam-recoil double polarization measurement of \eta electroproduction on the proton in the region of the S_{11}(1535) resonance

The beam-recoil double polarization P_{x'}^h and P_{z'}^h and the recoil polarization P_{y'} were measured for the first time for the p(\vec{e},e'\vec{p})\eta reaction at a four-momentum transfer of Q^2=0.1 GeV^2/c^2 and a center of mass production angle of \theta = 120^\circ at MAMI C. With a center of mass energy range of 1500 MeV < W < 1550 MeV the region of the S_{11}(1535) and D_{13}(1520) resonance was covered. The results are discussed in the framework of a phenomenological isobar model (Eta-MAID). While P_{x'}^h and P_{z'}^h are in good agreement with the model, P_{y'} shows a significant deviation, consistent with existing photoproduction data on the polarized-target asymmetry.Comment: 4 pages, 1 figur