Mean-field model of jet formation in a collapsing Bose-Einstein condensate

We perform a systematic numerical study, based on the time-dependent Gross-Pitaevskii equation, of jet formation in collapsing and exploding Bose-Einstein condensates as in the experiment by Donley et al (2001 Nature 412 295). In the actual experiment, via a Feshbach resonance, the scattering length of atomic interaction was suddenly changed from positive to negative on a pre-formed condensate. Consequently, the condensate collapsed and ejected atoms via explosion. On disruption of the collapse by suddenly changing the scattering length to zero, a radial jet of atoms was formed in the experiment. We present a satisfactory account of jet formation under the experimental conditions and also make predictions beyond experimental conditions which can be verified in future experiments.

Final state and thermodynamics of a dark energy universe

As it follows from the classical analysis, the typical final state of a dark energy universe where a dominant energy condition is violated is a finite-time, sudden future singularity (a big rip). For a number of dark energy universes (including scalar phantom and effective phantom theories as well as specific quintessence models) we demonstrate that quantum effects play the dominant role near a big rip, driving the universe out of a future singularity (or, at least, moderating it). As a consequence, the entropy bounds with quantum corrections become well defined near a big rip. Similarly, black hole mass loss due to phantom accretion is not so dramatic as was expected: masses do not vanish to zero due to the transient character of the phantom evolution stage. Some examples of cosmological evolution for a negative, time-dependent equation of state are also considered with the same conclusions. The application of negative entropy (or negative temperature) occurrence in the phantom thermodynamics is briefly discussed.

Flow evolution of a metallic slurry during thixoextrusion of an automotive valve

The aim of this work is to characterize a metallic slurry (Al-4.5%Cu) flow during thixoforming of an automotive valve. The necessary globular structure was obtained by first inoculating the alloy with TIBAL (5%Ti, 1%B, Al - rest) at 750.0°C, and then reheating to a state between liquidus and solidus prior to thixoforming. Two metallic slurries, with a solid phase of approximately 86.1 and 78.2 percent, were used to generate different experimental flow patterns during the thixoforming process. The flow of the material into the die was observed for total, and partial displacement (2.7, 5.4, 7.5mm) of the punch. The first displacement shows formation of the valve rod. The patterns at each step of displacement of the punch were preserved by quenching in water, thus revealing the profile of the die fill and microstructural evolution. Degeneration of the globular phase was observed along the piece thixoextruded. Thixoextrusion forces versus time curves were generated for partial and full displacement of the punch. Porosity was visible along the billet prior to thixoforming. However, some areas show that the porosity gradually decreased to zero as the thixoextrusion pressure increased. Turbulent, transient and laminar flow are analyzed in this work.

Tendências genéticas para características relacionadas à velocidade de crescimento em bovinos nelore na região nordeste do brasil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Fisioterapia no tratamento da dor orofacial de pacientes com disfunção temporomandibular crônica

Recent studies have shown consistent results using the physical therapy in cases of pain and limitation of movement from temporomandibular dysfunction. Thus, our objective was to assess the effect of ten sessions of physical therapy and laser therapy in treatment of muscular pain and arthralgias in a woman with temporomandibular dysfunction. The painful symptoms relief achieved by session was over 20 %, up to zero at the end of treatment. Results demonstrated that the treatment protocol used was effective to reduce the temporomandibular joint and the masseter muscle tension and a decreased of drugs by patient. However, more studies are needed to define with more accuracy the effect of other physiotherapy programs and its interaction with other treatment modalities.

Spin and pseudospin symmetries of the Dirac equation with confining central potentials

We derive the node structure of the radial functions which are solutions of the Dirac equation with scalar S and vector V confining central potentials, in the conditions of exact spin or pseudospin symmetry, i.e., when one has V=±S+C, where C is a constant. We show that the node structure for exact spin symmetry is the same as the one for central potentials which go to zero at infinity but for exact pseudospin symmetry the structure is reversed. We obtain the important result that it is possible to have positive energy bound solutions in exact pseudospin symmetry conditions for confining potentials of any shape, including naturally those used in hadron physics, from nuclear to quark models. Since this does not occur for potentials going to zero at large distances, which are used in nuclear relativistic mean-field potentials or in the atomic nucleus, this shows the decisive importance of the asymptotic behavior of the scalar and vector central potentials on the onset of pseudospin symmetry and on the node structure of the radial functions. Finally, we show that these results are still valid for negative energy bound solutions for antifermions. © 2013 American Physical Society.

Stable regions around Pluto

In a previous work, GiuliattiWinter et al. found several stable regions for test particles in orbit around Pluto associated with families of periodic orbits obtained in the circular, restricted three-body problem. They have shown that a possible eccentricity of the Pluto-Charon binary slightly reduces but does not destroy any of these stable regions. In thiswork, we extended their results by analysing the cases with the orbital inclination (I) equal to zero and considering the argument of pericentre (w) equal to 90°, 180° and 270°. We explore the influence of the orbital inclination of the particles in these stable regions. In this case, the initial inclination varies from 10° to 170° in steps of 10°. We also present a sample of results for the longitude of the ascending node Ω = 90°, considering the cases I = 20°, 50°, 130° and 180°. Our results show that stable regions are present in all of the inclined cases, except when the initial inclination of the particles is equal to 110°. A sample of 3D trajectories of quasi-periodic orbits were found related to the periodic orbits obtained in the planar case by Giuliatti Winter et al. © 2013 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.

Monte Carlo simulation applied in total reflection X-ray fluorescence: Preliminary results

The X-ray Fluorescence (XRF) analysis is a technique for the qualitative and quantitative determination of chemical constituents in a sample. This method is based on detection of the characteristic radiation intensities emitted by the elements of the sample, when properly excited. A variant of this technique is the Total Reflection X-ray Fluorescence (TXRF) that utilizes electromagnetic radiation as excitation source. In total reflection of X-ray, the angle of refraction of the incident beam tends to zero and the refracted beam is tangent to the sample support interface. Thus, there is a minimum angle of incidence at which no refracted beam exists and all incident radiation undergoes total reflection. In this study, we evaluated the influence of the energy variation of the beam of incident x-rays, using the MCNPX code (Monte Carlo NParticle) based on Monte Carlo method. © 2013 AIP Publishing LLC.

Perfil de cortisol, glicemia e de parâmetros sanguineos de girinos de rã-touro, Rana catesbeiana, em diferentes densidades e após exposição aérea

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Controle robusto com realimentação derivativa de sistemas não lineares via LMI

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Proteção de bovinos contra Haemonchus placei e Haemonchus contortus após imunização com antígenos oriundos da membrana intestinal de H. contortus

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cuba: evolución económica durante 2008 y perspectivas para 2009

Incluye Bibliografía

Efeito da escória de siderurgia na nutrição e desenvolvimento inicial de eucalipto

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Probing the infraed behavior of the ghost-gluon vertex in quantum chromodynamics

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Theoretical perspectives on the dynamics of communities with intraguild predation

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)