2,777 research outputs found
El Mercosur en 1997: ¿consolidación o incertidumbre?
En españolLos autores desarrollaron un detallado perfil del Mercosur, a partir de sus ejes centrales (desde antecedentes, gravitación económica, características principales del proceso de transición y de la unión Aduanera, como el relacionamiento exerno), con la importacia de refrescar los hechos -unilaterales y comunes- que mayor trascendencia han tenido en su evolución. A partir de dicho planteo se obtiene un claro panorama del proceso y cuáles son los desafíos a enfrentar para lograr la "maduración del Mercosur como bloque comercial emergente".En inglésThe authors draw a detailed profile of Mercosur, taking as a starting point its central axes ( antecedents, economic gravitation, main characteristics of the transitional process and the Customs Union, as well as its foreign relations), with the aim of refreshing the facts -unilateral and common- which have proved to be most outstanding in its evolution. In following this, a clear panorama of the process is achieved, as well as of which the challenges to face are, so as to reach "the maturity of Mercosur as an emergent commercial block"
Uses of Chern-Simons actions
The role of Chern-Simons (CS) actions is reviewed, starting from the
observation that all classical actions in Hamiltonian form can be viewed as 0+1
CS systems, in the same class with the coupling between the electromagnetic
field and a point charge. Some suggestions are derived that could shed some
light on the quantization problem in D=2n-1>3 dimensions.Comment: 17 pages, no figures. Ten Years of AdS/CFT conference, a workshop to
celebrate the tenth anniversary of the Maldacena Conjecture. Buenos Aires,
December 2007. Added references, corrected typo
Actores y sociedad civil en el MERCOSUR
El trabajo tiene como objetivo mostrar el surgimiento de una sociedad civil en el proceso de integración del MERCOSUR. Para ello, comienza ubicando los actores en términos de los distintos círculos de influencia en relación con los decisores y negociadores. Esta ubicación posibilita analizar la respuesta estructural de los distintos actores frente a los avances del proceso de integración. Esta respuesta permite una aproximación a la posición de los distintos actores frente al desborde funcional del proceso de integración. Finalmente el trabajo encara el estudio de la respuesta actitudinal de los actores en relación con los temas de la agenda subregional. Es en la posición frente a estos temas que surge el mapa activo de la sociedad civil del MERCOSUR. Este plano que actualmente está en construcción amerita nuevos estudios que permitan visualizar los caminos hacia la consolidación de este espacio de integración subregional
Prevalence of low weight and small for gestational age in Argentina: Comparison between the INTERGROWTH-21st standard and an Argentine reference
Introduction. The term “low birth weight” ( 42+6 weeks, twin pregnancy, and missing data on weight, GA, and sex. Prevalence was estimated by sex, region, and prematurity category for LW and SGA according to the standard and the reference. Agreement was assessed using the Kappa index. Results. The prevalence of LW and SGA was higher according to the standard among preterm newborns; the contrary was observed among fullterm newborns. Statistical significance varied based on GA category, sex, and region. A higher prevalence was observed in the northern regions of Argentina, and agreement among prevalence values ranged from weak to very good. Conclusions. Prevalence agreement of LW and SGA observed according to the standard and the reference among preterm and full-term newborn infants was moderate, with interregional variability. Results propose new auxological perspectives in the epidemiological assessment of intrauterine growth restriction in Argentina.Fil: Revollo, Gabriela Beatriz. Universidad Nacional de Jujuy. Instituto de Biología de la Altura; Argentina. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; ArgentinaFil: Martinez, Jorge Ivan. Universidad Nacional de Jujuy. Instituto de Biología de la Altura; Argentina. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; ArgentinaFil: Grandi, Carlos. Universidade de Sao Paulo; BrasilFil: Alfaro Gómez, Emma Laura. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; Argentina. Universidad Nacional de Jujuy. Instituto de Biología de la Altura; ArgentinaFil: Dipierri, José E.. Universidad Nacional de Jujuy. Instituto de Biología de la Altura; Argentina. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; Argentin
Prevalencias de bajo peso y pequeño para la edad gestacional en Argentina: comparación entre el estándar INTERGROWTH-21st y una referencia argentina
Introducción. Bajo peso al nacer ( 42+6 semanas, embarazo gemelar y ausencia de datos de peso, EG y sexo. Se calcularon las prevalencias por sexo, regiones y categorías de prematurez de BP y PEG con el estándar y la referencia. La concordancia se evaluó con Kappa. Resultados. Las prevalencias de BP y PEG fueron más altas con el estándar en pretérmino; lo contrario se observó en recién nacidos a término. La significación estadística varió según categorías de EG, sexo y regiones. Las prevalencias más altas se presentaron en regiones del norte argentino y las concordancias entre prevalencias oscilaron entre débiles y muy buenas. Conclusiones. Las concordancias de prevalencias de BP y PEG obtenidas con el estándar y la referencia en pretérmino y a término fueron moderadas, y se observó variabilidad interregional. Los resultados plantean nuevas perspectivas auxológicas en la evaluación epidemiológica del retardo del crecimiento intrauterino en Argentina.Fil: Revollo, Gabriela Beatriz. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; ArgentinaFil: Martinez, Jorge Ivan. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas. San Salvador de Jujuy; ArgentinaFil: Grandi, Carlos. Universidad de San Pablo; BrasilFil: Alfaro Gómez, Emma Laura. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; ArgentinaFil: Dipierri, Jose Edgardo. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; Argentin
The Atacama Cosmology Telescope: Physical Properties and Purity of a Galaxy Cluster Sample Selected via the Sunyaev-Zel'dovich Effect
We present optical and X-ray properties for the first confirmed galaxy
cluster sample selected by the Sunyaev-Zel'dovich Effect from 148 GHz maps over
455 square degrees of sky made with the Atacama Cosmology Telescope. These
maps, coupled with multi-band imaging on 4-meter-class optical telescopes, have
yielded a sample of 23 galaxy clusters with redshifts between 0.118 and 1.066.
Of these 23 clusters, 10 are newly discovered. The selection of this sample is
approximately mass limited and essentially independent of redshift. We provide
optical positions, images, redshifts and X-ray fluxes and luminosities for the
full sample, and X-ray temperatures of an important subset. The mass limit of
the full sample is around 8e14 Msun, with a number distribution that peaks
around a redshift of 0.4. For the 10 highest significance SZE-selected cluster
candidates, all of which are optically confirmed, the mass threshold is 1e15
Msun and the redshift range is 0.167 to 1.066. Archival observations from
Chandra, XMM-Newton, and ROSAT provide X-ray luminosities and temperatures that
are broadly consistent with this mass threshold. Our optical follow-up
procedure also allowed us to assess the purity of the ACT cluster sample.
Eighty (one hundred) percent of the 148 GHz candidates with signal-to-noise
ratios greater than 5.1 (5.7) are confirmed as massive clusters. The reported
sample represents one of the largest SZE-selected sample of massive clusters
over all redshifts within a cosmologically-significant survey volume, which
will enable cosmological studies as well as future studies on the evolution,
morphology, and stellar populations in the most massive clusters in the
Universe.Comment: 20 pages, 15 figures, 6 tables. Accepted for publication in ApJ.
Higher resolution figures available at:
http://peumo.rutgers.edu/~felipe/e-prints
Elucidation of the assembly events required for the recruitment of Utp20, Imp4 and Bms1 onto nascent pre-ribosomes
The 90S pre-ribosome, also known as the small subunit (SSU) processome, is a large multisubunit particle required for the production of the 18S rRNA from a pre-rRNA precursor. Recently, it has been shown that the formation of this particle entails the initial association of the tUTP subunit with the nascent pre-RNA and, subsequently, the binding of Rrp5/UTP-C and U3 snoRNP/UTP-B subunits in two independent assembly branches. However, the mode of assembly of other 90S pre-ribosome components remains obscure as yet. In this study, we have investigated the assembly of three proteins (Utp20, Imp4 and Bms1) previously regarded as potential nucleating factors of the 90S particle. Here, we demonstrate that the loading of those three proteins onto the pre-rRNA takes place independently of Rrp5/UTP-C and, instead, occurs downstream of the tUTP and U3/UTP-B subcomplexes. We also demonstrate that Bms1 and Utp20 are required for the recruitment of a subset of proteins to nascent pre-ribosomes. Finally, we show that proteins associated through secondary steps condition the stability of the two assembly branches in partially assembled pre-ribosomes. These results provide new information about the functional relationships among 90S particle components and the events that are required for their stepwise incorporation onto the primary pre-rRNA
Greenstone: Un software libre de código abierto para la construcción de bibliotecas digitales. Experiencias en América Latina y el Caribe
UNESCO's Office in Montevideo releases a book on the use of Greenstone, open source digital library software, in Latin America. Entitled Greenstone: Un software libre de código abierto para la construcción de bibliotecas digitales. Experiencias en América Latina y el Caribe, the publication explains the multiple applications of Greenstone in the region and the work of national Greenstone’s centres
XIPE: the X-ray Imaging Polarimetry Explorer
X-ray polarimetry, sometimes alone, and sometimes coupled to spectral and
temporal variability measurements and to imaging, allows a wealth of physical
phenomena in astrophysics to be studied. X-ray polarimetry investigates the
acceleration process, for example, including those typical of magnetic
reconnection in solar flares, but also emission in the strong magnetic fields
of neutron stars and white dwarfs. It detects scattering in asymmetric
structures such as accretion disks and columns, and in the so-called molecular
torus and ionization cones. In addition, it allows fundamental physics in
regimes of gravity and of magnetic field intensity not accessible to
experiments on the Earth to be probed. Finally, models that describe
fundamental interactions (e.g. quantum gravity and the extension of the
Standard Model) can be tested. We describe in this paper the X-ray Imaging
Polarimetry Explorer (XIPE), proposed in June 2012 to the first ESA call for a
small mission with a launch in 2017 but not selected. XIPE is composed of two
out of the three existing JET-X telescopes with two Gas Pixel Detectors (GPD)
filled with a He-DME mixture at their focus and two additional GPDs filled with
pressurized Ar-DME facing the sun. The Minimum Detectable Polarization is 14 %
at 1 mCrab in 10E5 s (2-10 keV) and 0.6 % for an X10 class flare. The Half
Energy Width, measured at PANTER X-ray test facility (MPE, Germany) with JET-X
optics is 24 arcsec. XIPE takes advantage of a low-earth equatorial orbit with
Malindi as down-link station and of a Mission Operation Center (MOC) at INPE
(Brazil).Comment: 49 pages, 14 figures, 6 tables. Paper published in Experimental
Astronomy http://link.springer.com/journal/1068
Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV
The performance of muon reconstruction, identification, and triggering in CMS
has been studied using 40 inverse picobarns of data collected in pp collisions
at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection
criteria covering a wide range of physics analysis needs have been examined.
For all considered selections, the efficiency to reconstruct and identify a
muon with a transverse momentum pT larger than a few GeV is above 95% over the
whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4,
while the probability to misidentify a hadron as a muon is well below 1%. The
efficiency to trigger on single muons with pT above a few GeV is higher than
90% over the full eta range, and typically substantially better. The overall
momentum scale is measured to a precision of 0.2% with muons from Z decays. The
transverse momentum resolution varies from 1% to 6% depending on pseudorapidity
for muons with pT below 100 GeV and, using cosmic rays, it is shown to be
better than 10% in the central region up to pT = 1 TeV. Observed distributions
of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO
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