9,335 research outputs found
Percolation approach to quark gluon plasma in high energy pp collisions
We apply continuum percolation to proton-proton collisions and look for the
possible threshold to phase transition from confined nuclear matter to quark
gluon plasma. Making the assumption that J/Psi suppression is a good signal to
the transition, we discuss this phenomenon for pp collisions, in the framework
of a dual model with strings.Comment: 8 pages, 3 figure
Deconstructing double-barred galaxies in 2D and 3D. II. Two distinct groups of inner bars
The intrinsic photometric properties of inner and outer stellar bars within
17 double-barred galaxies are thoroughly studied through a photometric analysis
consisting of: i) two-dimensional multi-component photometric decompositions,
and ii) three-dimensional statistical deprojections for measuring the
thickening of bars, thus retrieving their 3D shape. The results are compared
with previous measurements obtained with the widely used analysis of integrated
light. Large-scale bars in single- and double-barred systems show similar
sizes, and inner bars may be longer than outer bars in different galaxies. We
find two distinct groups of inner bars attending to their in-plane length and
ellipticity, resulting in a bimodal behaviour for the inner/outer bar length
ratio. Such bimodality is related neither to the properties of the host galaxy
nor the dominant bulge, and it does not show a counterpart in the dimension off
the disc plane. The group of long inner bars lays at the lower end of the outer
bar length vs. ellipticity correlation, whereas the short inner bars are out of
that relation. We suggest that this behaviour could be due to either a
different nature of the inner discs from which the inner bars are dynamically
formed, or a different assembly stage for the inner bars. This last possibility
would imply that the dynamical assembly of inner bars is a slow process taking
several Gyr to happen. We have also explored whether all large-scale bars are
prone to develop an inner bar at some stage of their lives, possibility we
cannot fully confirm or discard.Comment: 14 pages, 8 figures, 1 table. Accepted for publication in MNRA
Critical behaviour of the compactified theory
We investigate the critical behaviour of the -component Euclidean model at leading order in -expansion. We consider it in
three situations: confined between two parallel planes a distance apart
from one another, confined to an infinitely long cylinder having a square
cross-section of area and to a cubic box of volume . Taking the mass
term in the form , we retrieve Ginzburg-Landau
models which are supposed to describe samples of a material undergoing a phase
transition, respectively in the form of a film, a wire and of a grain, whose
bulk transition temperature () is known. We obtain equations for the
critical temperature as functions of (film), (wire), (grain) and of
, and determine the limiting sizes sustaining the transition.Comment: 12 pages, no figure
Ionospheric response to the 2009 sudden stratospheric warming over the equatorial, low, and middle latitudes in the South American sector
The present study investigates the ionospheric total electron content (TEC) and F-layer response in the Southern Hemisphere equatorial, low, and middle latitudes due to major sudden stratospheric warming (SSW) event, which took place during January-February 2009 in the Northern Hemisphere. In this study, using 17 ground-based dual frequency GPS stations and two ionosonde stations spanning latitudes from 2.8°N to 53.8°S, longitudes from 36.7°W to 67.8°W over the South American sector, it is observed that the ionosphere was significantly disturbed by the SSW event from the equator to the midlatitudes. During day of year 26 and 27 at 14:00 UT, the TEC was two times larger than that observed during average quiet days. The vertical TEC at all 17 GPS and two ionosonde stations shows significant deviations lasting for several days after the SSW temperature peak. Using one GPS station located at Rio Grande (53.8°S, 67.8°W, midlatitude South America sector), it is reported for the first time that the midlatitude in the Southern Hemisphere was disturbed by the SSW event in the Northern Hemisphere.Fil: Fagundes, P. R.. Universidade do Vale do ParaÃba; BrasilFil: Goncharenko, L. P.. Massachusetts Institute of Technology; Estados UnidosFil: De Abreu, A. J.. Universidade do Vale do ParaÃba; BrasilFil: Venkatesh, K.. Universidade do Vale do ParaÃba; BrasilFil: Pezzopane, M.. Istituto Nazionale Di Geofisica E Vulcanologia; ItaliaFil: De Jesus, R.. Universidade do Vale do ParaÃba; BrasilFil: Gende, Mauricio Alfredo. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y GeofÃsicas; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Coster, A. J.. Massachusetts Institute of Technology; Estados UnidosFil: Pillat, V. G.. Universidade do Vale do ParaÃba; Brasi
Cultivares de feijoeiro comum para o Estado de MInas Gerais.
As novas cultivares de feijoeiro comum recomendadas para cultivo em Minas Gerais vêm proporcionar aos agricultores várias opções quanto ao tipo de grão, resistência à doenças, porte da planta e precocidade, entre outras caracterÃsticas. A escolha deve recair sobre aquela que melhor atenda à s necessidades, condições de cultivo e oportunidade de comercialização.bitstream/CNPAF/22245/1/circ_65.pd
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