125,745 research outputs found

    Compactifications of the universal Jacobian over curves with marked points

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    We construct modular compactifications of the universal Jacobian stack over the moduli stack of reduced curves with marked points depending on stability parameters obtained out of fixing a vector bundle on the universal curve. When restricted to the locus of stable marked curves, our compactifications are Deligne-Mumford irreducible smooth stacks endowed with projective moduli spaces and, following Esteves approach to the construction of fine compactifications of Jacobians, they parametrize torsion-free rank-1 simple sheaves satisfying a stability condition with respect to the fixed vector bundle. We also study a number of properties of our compactifications as the existence of forgetful and clutching morphisms and as well of sections from the moduli stack of stable curves with marked points. We conclude by indicating a number of different possible applications for our constructions.Comment: Exposition improved. Added Application to Universal N\'eron models for Jacobians of curves with marked point

    Electromagnetic structure and weak decay of meson K in a light-front QCD-inspired

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    The kaon electromagnetic (e.m.) form factor is reviewed considering a light-front constituent quark model. In this approach, it is discussed the relevance of the quark-antiquark pair terms for the full covariance of the e.m. current. It is also verified, by considering a QCD dynamical model, that a good agreement with experimental data can be obtained for the kaon weak decay constant once a probability of about 80% of the valence component is taken into account.Comment: 4 pages and 1 figure eps. To appear Nucl. Phys. A (2007

    The sigmatic future and the genetic affiliation of Venetic: Latin faxo 'I shall make' and Venetic vha.g.s.to 'he made'

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    Latin has a so-called sigmatic future faxo 'I shall make'. Scholars are divided as to the origins and antiquity of faxo; some believe it to go back to desideratives, others to aorists, and some argue that the formation arose within Latin, others that it can be traced back to Proto-Italic. Closely connected with these problems are the questions whether Venetic is an Italic language and whether its past ('aorist') tense vha.g.s.to 'he made' is related to fax (o) over bar. I intend to show that fax (o) over bar is based on inherited s-aorists, not on desideratives, that the formation arose late, within Latin itself rather than within Proto-Italic, and that there was never a past indicative beside it. Because of the last two reasons, vha.g.s.to must be independent of fax (o) over bar. Venetic may still be an Italic language, but the form vha.g.s.to cannot be used as an argument in favour of such a connection

    On the taxonomic placement of the genus Sinnamarynus (Hemiptera: Heteroptera: Reduviidae), and a new record of S. rasahusoides from Peru

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    The genus Sinnamarynus Maldonado Capriles & Bérenger, 1996 (Hemiptera: Heteroptera: Reduviidae), originally placed into the subfamily Reduviinae, is transferred to the subfamily Peiratinae. Dorsal habitus and the male genitalia of the type species, S. rasahusoides Maldonado Capriles & Bérenger, 1996 are illustrated. The genus and species are recorded for the first time from Peru.Fil: Melo, María Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; Argentin
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