202 research outputs found

    Desarrollo, implementaciĂłn y utilizaciĂłn de modelos para el procesamiento automĂĄtico de textos

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    El libro recoge ponencias y talleres seleccionados de JALIMI 2005 (Jornadas Argentinas de LingĂŒĂ­stica InformĂĄtica: ModelizaciĂłn e IngenierĂ­a), y estĂĄ organizado en nueve capĂ­tulos y un apĂ©ndice. Si bien hay sustantivas diferencias en los enfoques, las metodologĂ­as, las propiedades especĂ­ficas estudiadas y las aplicaciones propuestas o proyectadas, todos los capĂ­tulos comunican resultados de investigaciones que pretenden contribuir a alcanzar el objetivo a largo plazo de la LingĂŒĂ­stica InformĂĄtica, a saber: emular en tĂ©rminos cibernĂ©ticos la extraordinaria capacidad humana de producir y comprender textos en lengua natural

    Hybrid imaging and timing ps laser excitation diagnostics for pulsed antihydrogen production

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    open48siIn this work we present a hybrid detection method providing simultaneous imaging and timing information suitable for fully monitoring positronium (Ps) formation, its laser excitation, and its spatial propagation for the first trials of pulsed antihydrogen (H) production through a charge-exchange reaction with trapped antiprotons (p). This combined method, based on the synchronous acquisition of an EJ-200 scintillation detector and a microchannel plate (MCP) detector with a dual readout (phosphor screen image and electrical pick-up signal), allows all relevant events in the experiment to be accurately determined in time while allowing high resolution images of e+ from Ps laser photodissociations to be acquired. The timing calibration process of the two detectors discussed in details as well as the future perspectives opened by this method.openCaravita R.; Antonello M.; Belov A.; Bonomi G.; Brusa R.S.; Caccia M.; Camper A.; Castelli F.; Comparat D.; Consolati G.; Demetrio A.; Di Noto L.; Doser M.; Fani M.; Ferragut R.; Gerber S.; Giammarchi M.; Gligorova A.; Gloggler L.T.; Guatieri F.; Haider S.; Hinterberger A.; Khalidova O.; Krasnicky D.; Lagomarsino V.; Malbrunot C.; Mariazzi S.; Matveev V.; Muller S.R.; Nebbia G.; Nedelec P.; Oberthaler M.; Oswald E.; Pagano D.; Penasa L.; Petracek V.; Prelz F.; Rienacker B.; Rohne O.M.; Rotondi A.; Sandaker H.; Santoro R.; Testera G.; Tietje I.; Toso V.; Wolz T.; Zimmer C.; Zurlo N.Caravita, R.; Antonello, M.; Belov, A.; Bonomi, G.; Brusa, R. S.; Caccia, M.; Camper, A.; Castelli, F.; Comparat, D.; Consolati, G.; Demetrio, A.; Di Noto, L.; Doser, M.; Fani, M.; Ferragut, R.; Gerber, S.; Giammarchi, M.; Gligorova, A.; Gloggler, L. T.; Guatieri, F.; Haider, S.; Hinterberger, A.; Khalidova, O.; Krasnicky, D.; Lagomarsino, V.; Malbrunot, C.; Mariazzi, S.; Matveev, V.; Muller, S. R.; Nebbia, G.; Nedelec, P.; Oberthaler, M.; Oswald, E.; Pagano, D.; Penasa, L.; Petracek, V.; Prelz, F.; Rienacker, B.; Rohne, O. M.; Rotondi, A.; Sandaker, H.; Santoro, R.; Testera, G.; Tietje, I.; Toso, V.; Wolz, T.; Zimmer, C.; Zurlo, N

    Long-term follow-up of certolizumab pegol in uveitis due to immune-mediated inflammatory diseases: multicentre study of 80 patients

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    ObjectivesTo evaluate effectiveness and safety of certolizumab pegol (CZP) in uveitis due to immune-mediated inflammatory diseases (IMID).MethodsMulticentre study of CZP-treated patients with IMID uveitis refractory to conventional immunosuppressant. Effectiveness was assessed through the following ocular parameters: best-corrected visual acuity, anterior chamber cells, vitritis, macular thickness and retinal vasculitis. These variables were compared between the baseline, and first week, first, third, sixth months, first and second year.ResultsWe studied 80 (33 men/47 women) patients (111 affected eyes) with a mean age of 41.6 +/- 11.7 years. The IMID included were: spondyloarthritis (n=43), Behcet's disease (n=10), psoriatic arthritis (n=8), Crohn's disease (n=4), sarcoidosis (n=2), juvenile idiopathic arthritis (n=1), reactive arthritis (n=1), rheumatoid arthritis (n=1), relapsing polychondritis (n=1),ConclusionsCZP seems to be effective and safe in uveitis related to different IMID, even in patients refractory to previous biological drugs

    Techniques for production and detection of 23S positronium

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    In this work, we show recent measurements of 23S long-lived positronium production via spontaneous decay from the 33P level. The possibility to tune the velocity of the 23S positronium, excited following this scheme, is presented. In the light of these results, we discuss the use of the 33P→23S transition to realize a monochromatic pulsed 23S positronium beam with low angular divergence. Preliminary tests of 23S beam production are presented. The possibility to overcome the natural 33P→23S branching ratio via stimulated emission, and thus increasing the intensity of the 23S source, is also shown. A position-sensitive detector for a pulsed beam of positronium, with spatial resolution of ≈ 90 ÎŒm, is finally described in view of its possible application for the spatial characterization of the 23S beam

    Laser excitation of the n=3 level of positronium for antihydrogen production

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    We demonstrate the laser excitation of the n = 3 state of positronium (Ps) in vacuum. A combination of a specially designed pulsed slow positron beam and a high-efficiency converter target was used to produce Ps. Its annihilation was recorded by single-shot positronium annihilation lifetime spectroscopy. Pulsed laser excitation of the n = 3 level at a wavelength lambda approximate to 205 nm was monitored via Ps photoionization induced by a second intense laser pulse at lambda = 1064 nm. About 15% of the overall positronium emitted into vacuum was excited to n = 3 and photoionized. Saturation of both the n = 3 excitation and the following photoionization was observed and explained by a simple rate equation model. The positronium's transverse temperature was extracted by measuring the width of the Doppler-broadened absorption line. Moreover, excitation to Rydberg states n = 15 and 16 using n = 3 as the intermediate level was observed, giving an independent confirmation of excitation to the 3 P-3 state

    Velocity-selected production of 2S3 metastable positronium

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    Positronium in the 2 3 S metastable state exhibits a low electrical polarizability and a long lifetime (1140 ns), making it a promising candidate for interferometry experiments with a neutral matter-antimatter system. In the present work, 2 3 S positronium is produced, in the absence of an electric field, via spontaneous radiative decay from the 3 3 P level populated with a 205-nm UV laser pulse. Thanks to the short temporal length of the pulse, 1.5 ns full width at half maximum, different velocity populations of a positronium cloud emitted from a nanochanneled positron-positronium converter were selected by delaying the excitation pulse with respect to the production instant. 2 3 S positronium atoms with velocity tuned between 7 7 10 4 ms 121 and 10 7 10 4 ms 121 were thus produced. Depending on the selected velocity, a 2 3 S production efficiency ranging from 3c0.8% to 3c1.7%, with respect to the total amount of emitted positronium, was obtained. The observed results give a branching ratio for the 3 3 P-2 3 S spontaneous decay of (9.7 \ub1 2.7)%. The present velocity selection technique could allow one to produce an almost monochromatic beam of 3c1 7 10 3 2 3 S atoms with a velocity spread of <10 4 ms 121 and an angular divergence of 3c50 mrad

    Gravity and antimatter: The AEgIS experiment at CERN

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    open62siFrom the experimental point of view, very little is known about the gravitational interaction between matter and antimatter. In particular, the Weak Equivalence Principle, which is of paramount importance for the General Relativity, has not yet been directly probed with antimatter. The main goal of the AEgIS experiment at CERN is to perform a direct measurement of the gravitational force on antimatter. The idea is to measure the vertical displacement of a beam of cold antihydrogen atoms, traveling in the gravitational field of the Earth, by the means of a moiré deflectometer. An overview of the physics goals of the experiment, of its apparatus and of the first results is presented.openPagano D.; Aghion S.; Amsler C.; Bonomi G.; Brusa R.S.; Caccia M.; Caravita R.; Castelli F.; Cerchiari G.; Comparat D.; Consolati G.; Demetrio A.; Noto L.D.; Doser M.; Evans A.; Fani M.; Ferragut R.; Fesel J.; Fontana A.; Gerber S.; Giammarchi M.; Gligorova A.; Guatieri F.; Haider S.; Hinterberger A.; Holmestad H.; Kellerbauer A.; Khalidova O.; Krasnicky D.; Lagomarsino V.; Lansonneur P.; Lebrun P.; Malbrunot C.; Mariazzi S.; Marton J.; Matveev V.; Mazzotta Z.; Muller S.R.; Nebbia G.; Nedelec P.; Oberthaler M.; Pacifico N.; Penasa L.; Petracek V.; Prelz F.; Prevedelli M.; Ravelli L.; Rienaecker B.; Robert J.; Rohne O.M.; Rotondi A.; Sandaker H.; Santoro R.; Smestad L.; Sorrentino F.; Testera G.; Tietje I.C.; Widmann E.; Yzombard P.; Zimmer C.; Zmeskal J.; Zurlo N.Pagano, D.; Aghion, S.; Amsler, C.; Bonomi, G.; Brusa, R. S.; Caccia, M.; Caravita, R.; Castelli, F.; Cerchiari, G.; Comparat, D.; Consolati, G.; Demetrio, A.; Noto, L. D.; Doser, M.; Evans, A.; Fani, M.; Ferragut, R.; Fesel, J.; Fontana, A.; Gerber, S.; Giammarchi, M.; Gligorova, A.; Guatieri, F.; Haider, S.; Hinterberger, A.; Holmestad, H.; Kellerbauer, A.; Khalidova, O.; Krasnicky, D.; Lagomarsino, V.; Lansonneur, P.; Lebrun, P.; Malbrunot, C.; Mariazzi, S.; Marton, J.; Matveev, V.; Mazzotta, Z.; Muller, S. R.; Nebbia, G.; Nedelec, P.; Oberthaler, M.; Pacifico, N.; Penasa, L.; Petracek, V.; Prelz, F.; Prevedelli, M.; Ravelli, L.; Rienaecker, B.; Robert, J.; Rohne, O. M.; Rotondi, A.; Sandaker, H.; Santoro, R.; Smestad, L.; Sorrentino, F.; Testera, G.; Tietje, I. C.; Widmann, E.; Yzombard, P.; Zimmer, C.; Zmeskal, J.; Zurlo, N
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