Unification of SU(2)xU(1) Using a Generalized Covariant Derivative and U(3)

A generalization of the Yang-Mills covariant derivative, that uses both vector and scalar fields and transforms as a 4-vector contracted with Dirac matrices, is used to simplify and unify the Glashow-Weinberg-Salam model. Since SU(3) assigns the wrong hypercharge to the Higgs boson, it is necessary to use a special representation of U(3) to obtain all the correct quantum numbers. A surplus gauge scalar boson emerges in the process, but it uncouples from all other particles.Comment: 12 pages, no figures. To be published in Int. J. Mod. Phys.

Pseudogap and the specific heat of high TcT_c superconductors

The specific heat of a two dimensional repulsive Hubbard model with local interaction is investigated. We use the two-pole approximation which exhibits explicitly important correlations that are sources of the pseudogap anomaly. The interplay between the specific heat and the pseudogap is the main focus of the present work. Our self consistent numerical results show that above the occupation $n_T\approx 0.85$, the specific heat starts to decrease due to the presence of a pseudogap in the density of states. We have also observed a two peak structure in the specific heat. Such structure is robust with respect to the Coulomb interaction $U$ but it is significantly affected by the occupation $n_T$. A detailed study of the two peak structure is carried out in terms of the renormalized quasi-particle bands. The role of the second nearest neighbor hopping on the specific heat behavior and on the pseudogap, is extensively discussed.Comment: 6 pages, 6 figures, accepted for publication in Solid State Communication

Paraxiphidorus michelluci n.g., n.sp. from Argentina (Nematoda : Longidoridae)

#Paraxiphidorus miichelluci n.g., n.sp. est décrit sur trois spécimens provenant de sol non cultivé d'Argentine. Ce nouveau genre est caractérisé par : région labiale en relief; amphides en étrier à ouverture large; odontostyle à base fourchue; odontophore à ailettes faiblement développées; guide du stylet en position postérieure; suppléments ventromédians dépassant le niveau des spicules; queue convexe-conoïde. Il ressemble à #Xiphidorus Monteiro, 1976 et #Paralongidorus$ Siddiqi, Hooper & Khan, 1963 mais diffère du premier par la structure de l'amphide et du second par celle du stylet, la position du guide du stylet, ainsi que par le nombre et la disposition des suppléments ventro-médians (Résumé d'auteur

A queda no consumo per capita de arroz em contexto.

O objetivo do presente trabalho foi analisar a redução do consumo domiciliar e aparente per capita de arroz em um contexto mais amplo, considerando diversos itens que compõem o consumo das famílias brasileiras

Scaling laws for the decay of multiqubit entanglement

We investigate the decay of entanglement of generalized N-particle Greenberger-Horne-Zeilinger (GHZ) states interacting with independent reservoirs. Scaling laws for the decay of entanglement and for its finite-time extinction (sudden death) are derived for different types of reservoirs. The latter is found to increase with the number of particles. However, entanglement becomes arbitrarily small, and therefore useless as a resource, much before it completely disappears, around a time which is inversely proportional to the number of particles. We also show that the decay of multi-particle GHZ states can generate bound entangled states.Comment: Minor mistakes correcte

Consumo aparente per capita de arroz no Brasil, 1991 a 2010.

O objetivo deste trabalho foi estimar o consumo aparente per capita de arroz no Brasil de 1991 a 2010 e estabelecer sua relação com o consumo domiciliar per capita

Consumo per capita de feijão no Brasil de 1998 a 2010: uma comparação entre consumo aparente e consumo domiciliar.

O objetivo deste trabalho foi estimar o consumo aparente per capita de feijão no Brasil de 1991 a 2010 e estabelecer sua relação com o consumo domiciliar per capita.CONAFE

High Latitude HI in NGC 2613: Buoyant Disk-Halo Outflow

We combine new VLA D array HI data of NGC 2613 with previous high resolution data to show new disk-halo features in this galaxy. The global HI distribution is modeled in detail using a technique which can disentangle the effects of inclination from scale height and can also solve for the average volume density distribution in and perpendicular to the disk. The model shows that the galaxy's inclination is on the low end of the range given by Chaves & Irwin (2001) and that the HI disk is thin (z_e = 188 pc), showing no evidence for halo. Numerous discrete disk-halo features are observed, however, achieving z heights up to 28 kpc from mid-plane. One prominent feature in particular, of mass, 8X10^7 Msun and height, 22 kpc, is seen on the advancing side of the galaxy at a projected galactocentric radius of 15.5 kpc. If this feature achieves such high latitudes because of events in the disk alone, then input energies of order ~ 10^{56} ergs are required. We have instead investigated the feasibility of such a large feature being produced via buoyancy (with drag) within a hot, pre-existing X-ray corona. Reasonable plume densities, temperatures, stall height (~ 11 kpc), outflow velocities and ages can indeed be achieved in this way. The advantage of this scenario is that the input energy need only be sufficient to produce blow-out, a condition which requires a reduction of three orders of magnitude in energy. If this is correct, there should be an observable X-ray halo around NGC 2613.Comment: 32 pages 7 gif figures, accepted by Ap