Aspectos reprodutivos de caititus (Tayassu tajacu).

Caititus ou catetos (Tayassu tajacu) são animais gregários, que se adaptam a diversos habitats. Ocorrem praticamente em todo o continente americano e atualmente apresentam grande potencial para exploração zootécnica, devido à crescente demanda por sua carne e seu couro. Este artigo tem como objetivo revisar as características sexuais da espécie, com ênfase em aspectos que podem ser úteis para o estabelecimento de práticas reprodutivas, visando ao apoio a programas de conservação ou melhoramento genético

Spin-1/2 fermions with attractive interaction in an optical lattice

We study attractive fermions in an optical lattice superimposed by a trapping potential, such that fermions may form bosonic molecules. We map the model onto nonlinear field equations depending on the Nambu-Gor'kov propagator. The resulting field equations where solved numerically by a relaxation technique that allowed us to calculate the inhomogeneous densities of fermions and condensed molecules at zero temperature. When the interactions between fermions are strong there is a competition between unbound fermions and bound molecules leading to an unexpected reduction of the non-homogeneous density of fermions at the center of the trap.Comment: 10 pages, 7 figures; revise

Kondo effect in two-dimensional disordered electron systems

We investigate the Kondo effect in two-dimensional disordered electron systems using a finite-temperature quantum Monte Carlo method. Depending on the position of a magnetic impurity, the local moment is screened or unscreened by the spin of the conduction electron. On the basis of the results, we show that the distribution of the Kondo temperature becomes wide and the weight at $T_K=0$ becomes large as randomness increases. The average susceptibility shows a weak power-law or logarithmic divergence at low temperature, indicating a non-Fermi-liquid behavior.Comment: 2 pages, 2 figures, to be published in supplement of J. Phys. Soc. Japan, Proceedings of Localisation 2002, (Tokyo, Japan, 2002

Supercurrent induced by tunneling Bogoliubov excitations in a Bose-Einstein condensate

We study the tunneling of Bogoliubov excitations through a barrier in a Bose-Einstein condensate. We extend our previous work [Phys. Rev. A \textbf{78}, 013628 (2008)] to the case when condensate densities are different between the left and right of the barrier potential. In the framework of the Bogoliubov mean-field theory, we calculate the transmission probability and phase shift, as well as the energy flux and quasiparticle current carried by Bogoliubov excitations. We find that Bogoliubov phonons twist the condensate phase due to a back-reaction effect, which induces the Josephson supercurrent. While the total current given by the sum of quasiparticle current and induced supercurrent is conserved, the quasiparticle current flowing through the barrier potential is shown to be remarkably enhanced in the low energy region. When the condensate densities are different between the left and right of the barrier, the excess quasiparticle current, as well as the induced supercurrent, remains finite far away from the barrier. We also consider the tunneling of excitations and atoms through the boundary between the normal and superfluid regions. We show that supercurrent can be generated inside the condensate by injecting free atoms from outside. On the other hand, atoms are emitted when the Bogoliubov phonons propagate toward the phase boundary from the superfluid region.Comment: 36 pages, 12 figures, revised version as accepted by Phys. Rev.

Chandra observation of the central galaxies in A1060 cluster of galaxies

Chandra observation of the central region of the A1060 cluster of galaxies resolved X-ray emission from two giant elliptical galaxies, NGC 3311 and NGC 3309. The emission from these galaxies consists of two components, namely the hot interstellar medium (ISM) and the low-mass X-ray binaries (LMXBs). We found the spatial extent of the ISM component was much smaller than that of stars for both galaxies, while the ratios of X-ray to optical blue-band luminosities were rather low but within the general scatter for elliptical galaxies. After subtracting the LMXB component, the ISM is shown to be in pressure balance with the intracluster medium of A1060 at the outer boundary of the ISM. These results imply that the hot gas supplied from stellar mass loss is confined by the external pressure of the intracluster medium, with the thermal conduction likely to be suppressed. The cD galaxy NGC 3311 does not exhibit the extended potential structure which is commonly seen in bright elliptical galaxies, and we discuss the possible evolution history of the very isothermal cluster A1060.Comment: 12 pages, 7 figures, Latex2e(emulateapj5), accepted in Ap

Effective action approach and Carlson-Goldman mode in d-wave superconductors

We theoretically investigate the Carlson-Goldman (CG) mode in two-dimensional clean d-wave superconductors using the effective ``phase only'' action formalism. In conventional s-wave superconductors, it is known that the CG mode is observed as a peak in the structure factor of the pair susceptibility $S(\Omega, \mathbf{K})$ only just below the transition temperature T_c and only in dirty systems. On the other hand, our analytical results support the statement by Y.Ohashi and S.Takada, Phys.Rev.B {\bf 62}, 5971 (2000) that in d-wave superconductors the CG mode can exist in clean systems down to the much lower temperatures, $T \approx 0.1 T_c$. We also consider the manifestations of the CG mode in the density-density and current-current correlators and discuss the gauge independence of the obtained results.Comment: 23 pages, RevTeX4, 12 EPS figures; final version to appear in PR

Efeito de BAP sobre a proliferação de brotos in vitro de Schizolobium amazonicum Huber ex Ducke (paricá).

O paricá, planta nativa das florestas tropicais, pertencente à família das caesalpinaceae, é uma espécie considerada com grande potencial devido à sua larga utilização. Com o objetivo de multiplicação da espécie in vitro, segmentos caulinares de plântulas estabelecidas in vitro foram excisados e inoculados em meio MS sólido suplementado com 0; 1,0; 1,5; 2,0; 2,5 e 3,0 mg.L-1 de BAP, 3% de sacarose e 0,1% de PVP. As atividades foram realizadas no Laboratório de Recursos Genéticos e Biotecnologia da Embrapa Amazônia Oriental, Belém (PA). As culturas foram mantidas sob fotoperíodo de 16 horas luz e 25+ 1°C de temperatura. Após três semanas realizou-se a avaliação com a contagem do número e comprimento de brotos por explante. O tratamento com 3 mg.L-1 BAP foi o que apresentou maior número de proliferação dos brotos, com 2,14 brotos por explante. Posteriormente, os brotos foram transferidos para o meio MS nas mesmas condições de cultivo para enraizamento