Ecologia de populações de porco monteiro no Pantanal do Brasil

O porco monteiro chegou ao Pantanal há cerca de dois séculos e, desde então, tem sido considerado como a principal espécie cinegética (de interesse para a caça) na região. Suas populações vivem livres na planície e independentes da atividade humana, exceto pelo manejo tradicional que age como fator de controle populacional dos rebanhos. Considerando que a espécie apresenta potencial para utilização econômica e que pode vir a compor a pauta de produtos com certificação de origem no Pantanal, informações sobre a ecologia das populações presentes na planície são estratégicas. Este artigo apresenta um apanhado sobre as informações disponíveis a respeito da espécie e discute aspectos da dinâmica de suas populações, com base em projeções obtidas utilizando-se o software VORTEX 9.6.bitstream/CPAP-2010/57340/1/DOC106.pd

Lambda-proton correlations in relativistic heavy ion collisions

The prospect of using lambda-proton correlations to extract source sizes in relativistic heavy ion collisions is investigated. It is found that the strong interaction induces a large peak in the correlation function that provides more sensitive source size measurements than two-proton correlations under some circumstances. The prospect of using lambda-proton correlations to measure the time lag between lambda and proton emissions is also studied.Comment: 4 pages, 3 figure, revtex style. Two short paragraphs are added at referees' recommendations. Phys. Rev. Lett. in pres

Variational calculations of the Λ\Lambda-seperation energy of the Λ17_{\Lambda}^{17}O hypernucleus

Variational Monte Carlo calculations have been made for the $_{ \Lambda}^{17}$O hypernucleus using realistic two- and three-baryon interactions. A two pion exchange potential with spin- and space-exchange components is used for the $\Lambda$N potential. Three-body two-pion exchange and strongly repulsive dispersive $\Lambda$NN interactions are also included. The trial wave function is constructed from pair- and triplet-correlation operators acting on a single particle determinant. These operators consist of central, spin, isospin, tensor and three- baryon potential components. A cluster Monte Carlo method is developed for noncentral correlations and is used with up to four-baryon clusters in our calculations. The three-baryon $\Lambda$NN force is discussed.Comment: 24 pages, 2 figs available by fax., for publication in Phys. Rev.

Phenomenological Lambda-Nuclear Interactions

Variational Monte Carlo calculations for ${_{\Lambda}^4}H$ (ground and excited states) and ${_{\Lambda}^5}He$ are performed to decipher information on ${\Lambda}$-nuclear interactions. Appropriate operatorial nuclear and ${\Lambda}$-nuclear correlations have been incorporated to minimize the expectation values of the energies. We use the Argonne $\upsilon_{18}$ two-body NN along with the Urbana IX three-body NNN interactions. The study demonstrates that a large part of the splitting energy in ${_{\Lambda}^4}H$ ($0^+-1^+$) is due to the three-body ${\Lambda}$ NN forces. $_{\Lambda}^{17}O$ hypernucleus is analyzed using the {\it s}-shell results. $\Lambda$ binding to nuclear matter is calculated within the variational framework using the Fermi-Hypernetted-Chain technique. There is a need to correctly incorporate the three-body ${\Lambda}$ NN correlations for $\Lambda$ binding to nuclear matter.Comment: 18 pages (TeX), 2 figure

Relativistic Mean Field Approximation in a Density Dependent Parametrization Model at Finite Temperature

In this work we calculate the equation of state of nuclear matter for different proton fractions at zero and finite temperature within the Thomas Fermi approach considering three different parameter sets: the well-known NL3 and TM1 and a density dependent parametrization proposed by Typel and Wolter. The main differences are outlined and the consequences of imposing beta-stability in these models are discussed.Comment: 13 pages, 10 figure

The Shapes of Flux Domains in the Intermediate State of Type-I Superconductors

In the intermediate state of a thin type-I superconductor magnetic flux penetrates in a disordered set of highly branched and fingered macroscopic domains. To understand these shapes, we study in detail a recently proposed "current-loop" (CL) model that models the intermediate state as a collection of tense current ribbons flowing along the superconducting-normal interfaces and subject to the constraint of global flux conservation. The validity of this model is tested through a detailed reanalysis of Landau's original conformal mapping treatment of the laminar state, in which the superconductor-normal interfaces are flared within the slab, and of a closely-related straight-lamina model. A simplified dynamical model is described that elucidates the nature of possible shape instabilities of flux stripes and stripe arrays, and numerical studies of the highly nonlinear regime of those instabilities demonstrate patterns like those seen experimentally. Of particular interest is the buckling instability commonly seen in the intermediate state. The free-boundary approach further allows for a calculation of the elastic properties of the laminar state, which closely resembles that of smectic liquid crystals. We suggest several new experiments to explore of flux domain shape instabilities, including an Eckhaus instability induced by changing the out-of-plane magnetic field, and an analog of the Helfrich-Hurault instability of smectics induced by an in-plane field.Comment: 23 pages, 22 bitmapped postscript figures, RevTex 3.0, submitted to Phys. Rev. B. Higher resolution figures may be obtained by contacting the author

Curvature energy effects on strange quark matter nucleation at finite density

We consider the effects of the curvature energy term on thermal strange quark matter nucleation in dense neutron matter. Lower bounds on the temperature at which this process can take place are given and compared to those without the curvature term.Comment: PlainTex, 6 pp., IAG-USP Rep.5

What Does Free Space Lambda-Lambda Interaction Predict for Lambda-Lambda Hypernuclei?

Data on Lambda-Lambda hypernuclei provide a unique method to learn details on the strangeness S =-2 sector of the baryon-baryon interaction. From the free space Bonn-Julich potentials, determined from data on baryon-baryon scattering in the S=0,-1 channels, we construct an interaction in the S =-2 sector to describe the experimentally known Lambda-Lambda hypernuclei. After including short--range (Jastrow) and RPA correlations, we find masses for these Lambda-Lambda hypernuclei in a reasonable agreement with data, taking into account theoretical and experimental uncertainties. Thus, we provide a natural extension, at low energies, of the Bonn-Julich OBE potentials to the S =-2 channel.Comment: 4 pages, 2 figures, revtex4 style. Minor changes in conclusions. References updated. Accepted in Phys. Rev. Let

Masses of Multiquark Droplets

The mass formulae for finite lumps of strange quark matter with $u$, $d$ and $s$ quarks, and non-strange quark matter consisting of $u$ and $d$ quarks are derived in a non-relativistic potential model. The finite-size effects comprising the surface, curvature and even, the Gauss curvature were consistently obtained, which shows a converging trend. It is found that there is a possibility for the formation of metastable strangelets of large mass. The model predicts low charge to mass ratio as the characteristic signature of strange matter in agreement with the relativistic studies. This study also yields an independent estimate for the bag energy density $B$, which is in agreement with the M.I.T bag model value.Comment: 24pages + 5 figures available upon request,Latex,IP/BBSR/93-3

Effective Field Theory for Bulk Properties of Nuclei

Recent progress in Lorentz-covariant quantum field theories of the nuclear many-body problem ({\em quantum hadrodynamics}, or QHD) is discussed. The importance of modern perspectives in effective field theory and density functional theory for understanding the successes of QHD is emphasized. The inclusion of hadronic electromagnetic structure and of nonanalytic terms in the energy functional is also considered.Comment: 11 pages, 0 figures, REVTeX 3.0; Invited talk at the 11th Conference on Recent Progress in Many-Body Theories (MB 11), Manchester, UK, July 9--13, 200