Alimentação dos peixes detritívoros da Baía Tuiuiú, rio Paraguai, Pantanal de Mato Grosso do Sul, Brasil.

Foram analisadas as dietas dos peixes detritívoros da baía Tuiuiú, meandro abandonado do rio Paraguai, próximo a Corumbá, Mato Grosso do Sul. Os peixes detritívoros apresentam estratégias específicas para o consumo do detrito orgânico existente na baía, como o sairu-boi, Potamorhina squamoralevis, que possui os olhos voltados para baixo para consumo do detrito acumulado no fundo, e o cascudo, Liposarcus anisitsi, que se coloca de barriga para cima para raspar os detritos e algas acumuladas nas raízes das macrófitas aquáticas. Para L. anisitsi, que teve os conteúdos estomacais analisados em quase todos os períodos de amostragem, foi encontrada correlação entre índice alimentar e altura de inundação e transparência da água. Peixes detritívoros apresentam adaptações e estratégias específicas para alimentar-se desse tipo especial de alimento nos ambientes inundáveis do Pantanal. Detritus feeding fishes from Tuiuiú bay, an oxbow lake of Paraguay River, near Corumbá city, Mato Grosso do Sul State were evaluated. Detritus feeding fishes have specific strategies to take this kind of food in the environment. Potamorhina squamoralevis has its eyes directed to the bottom to feed on detritus accumulated in the bay bottom while Liposarcus anisitsi, stay with the belly to the surface in order to scrape detritus and algae from the macrophyte roots. Correlations were found to alimentary index of L. anistisi in relation to river height and water transparency. Detritus feeding fishes have specific adaptations and strategies to take this kind of food in floodable environments in the Pantanal.bitstream/item/68605/1/BP115.pd

Decoherence of tripartite states - a trapped ion coupled to an optical cavity

We investigate the non-dissipative decoherence of three qubit system obtained by manipulating the state of a trapped two-level ion coupled to an optical cavity. Modelling the environment as a set of noninteracting harmonic oscillators, analytical expressions for the state operator of tripartite composite system, the probability of generating maximally entangled GHZ state, and the population inversion have been obtained. The pointer observable is the energy of the isolated quantum system. Coupling to environment results in exponential decay of off diagonal matrix elements of the state operator with time as well as a phase decoherence of the component states. Numerical calculations to examine the time evolution of GHZ state generation probability and population inversion for different system environment coupling strengths are performed. Using negativity as an entanglement measure and linear entropy as a measure of mixedness, the entanglement dynamics of the tripartite system in the presence of decoherence is analysed.Comment: Revised version, errors corrected and references added. 12 pages, 6 figures, Presented at ICSSUR May 2005, Besancon, Franc

Peixes herbivoros da planicie inundavel do Rio Miranda, Pantanal, Mato Grosso do Sul, Brasil.

Na planicie inundavel do baixo rio Miranda, foram encontradas 12 especies de peixes de habitos alimentares herbivoros. Sao: Markiana nigripinnis, Piabucus melanostoma, Metynnis mola, Metynnis maculatus, Mylossoma paraguayensis, Mylossoma orbignyanum, Myloplus levis, Hemiodus orthonops, Leporinus elongatus, Leporinus friderici, Leporinus lacustris e Schizodon borellii. Destas, 4 apresentam importancia economica para a pesca profissional e esportiva (M. paraguayensis, M. orbinyanum, L. elongatus e L. friderici). E discutida a importancia da herbivoria na cadeia alimentar dos peixes sulamericanos.bitstream/item/37446/1/BP10.pd

On the Infrared Behavior of the Pressure in Thermal Field Theories

We study non-perturbatively, via the Schwinger-Dyson equations, the leading infrared behavior of the pressure in the ladder approximation. This problem is discussed firstly in the context of a thermal scalar field theory, and the analysis is then extended to the Yang-Mills theory at high temperatures. Using the Feynman gauge, we find a system of two coupled integral equations for the gluon and ghost self-energies, which is solved analytically. The solutions of these equations show that the contributions to the pressure, when calculated in the ladder approximation, are finite in the infrared domain.Comment: 20 pages plus 4 figures available by request, IFUSP/P-100

Tetragonal tungsten bronze compounds: relaxor vs mixed ferroelectric - dipole glass behavior

We demonstrate that recent experimental data (E. Castel et al J.Phys. Cond. Mat. {\bf 21} (2009), 452201) on tungsten bronze compound (TBC) Ba$_2$Pr$_x$Nd$_{1-x}$FeNb$_4$O$_{15}$ can be well explained in our model predicting a crossover from ferroelectric ($x=0$) to orientational (dipole) glass ($x=1$), rather then relaxor, behavior. We show, that since a "classical" perovskite relaxor like Pb(Mn$_{1/3}$ Nb$_{2/3}$)O$_3$ is never a ferroelectric, the presence of ferroelectric hysteresis loops in TBC shows that this substance actually transits from ferroelectric to orientational glass phase with $x$ growth. To describe the above crossover theoretically, we use the simple replica-symmetric solution for disordered Ising model.Comment: 5 two-column pages, 4 figure

Comparação de métodos de estimativa da evapotranspiração de referência para Esperantina - PI.

O objetivo do trabalho foi comparar e avaliar o desempenho de métodos de estimativa de evapotranspiração de referência em relação ao método Penman-Monteith/FAO, visando proporcionar à região de Esperantina-PI, informações básicas para a estimativa da ETo. Os dados meteorológicos foram obtidos na estação meteorológica convencional do INMET, entre o período de 01/01/2008 à 31/12/2012 ,especificamente da unidade situada em Esperantina, PI, com latitude 03º54'06", longitude 42º14'01" W e altitude media de 59 m. Os dados obtidos foram divididos em dois períodos distintos: período seco (15/07) e período chuvoso (15/02). Os métodos de estimativa da evapotranspiração de referência utilizados foram os de Makking (MK), Jensen-Haise (JH), Priestley-Taylor (PT), Hargreaves-Samani (HS), Camargo (CA) e Ivanov (IVN), descritos em comparação ao método de Penman-Monteih (PM). Foram realizados cálculos de erro padrão de estimativa, dos coeficientes de determinação, correlação, o índice de Willmott e o coeficiente de desempenho entre os métodos avaliados e o padrão. Os métodos de Jensen-Haise, Priestley-Taylor e Makking apresentaram desempenho ótimo para os dois períodos estudados, quando comparados ao de Penman- Monteith, demonstrando que estes podem ser utilizados como uma alternativa para a estimativa da ETo no município de Esperantina-PI.CONBEA 2014

Caracterização físico-química de misturas de óleos vegetais para fins alimentares.

Made available in DSpace on 2014-03-11T23:27:20Z (GMT). No. of bitstreams: 1 reverdagrodesensus.pdf: 471915 bytes, checksum: 6684ed577c06cdb37397b04560fa8a02 (MD5) Previous issue date: 2014-03-10201

Superconductivity and spin-glass like behavior in system with Pd sheet sandwiched between graphene sheets

Pd-metal graphite (Pd-MG) has a layered structure, where each Pd sheet is sandwiched between adjacent graphene sheets. DC magnetization and AC magnetic susceptibility of Pd-MG have been measured using a SQUID magnetometer. Pd-MG undergoes a superconducting transition at $T_{c}$ ($= 3.63 \pm 0.04$ K). The superconductivity occurs in Pd sheets. The relaxation of $M_{ZFC}$ (aging), which is common to spin glass systems, is also observed below $T_{c}$. The relaxation rate $S(t)$ shows a peak at a characteristic time $t_{cr}$, which is longer than a wait time $t_{w}$. The irreversibility between $\chi_{ZFC}$ and $\chi_{FC}$ occurs well above $T_{c}$. The susceptibility $\chi_{FC}$ obeys a Curie-Weiss behavior with a negative Curie-Weiss temperature ($-13.1 \leq \Theta \leq -5.4$ K). The growth of antiferromagnetic order is limited by the disordered nature of nanographites, forming spin glass-like behavior at low temperatures in graphene sheets.Comment: 21 pages, 15 figures; submitted to J. Phys.: Condensed Matte

Lattice Gas Analogue Of SK Model: A paradigm for the glass transition

We investigate the connection between the well known Sherrington-Kirkpatrick Ising Spin Glass and the corresponding Lattice Gas model by analyzing the relation between their thermodynamical functions. We present results of replica approach in the Replica Symmetric approximation and discuss its stability as a function of temperature and external source. Next we examine the effects of first order Replica Symmetry Breaking at zero temperature. We finally compare SK results with ours and suggest how the latter could be relevant to a description of the structural glass transition.Comment: 33 Pages, LaTeX file; 15 Figures added, some grammatical corrections. To appear in Journal of Physics

Infrared behaviour of the pressure in g\phi^3 theory in 6 dimensions

In an earlier paper Almeida and Frenkel considered the calculation of the pressure in g\phi^3 theory in 6 dimensions via the Schwinger--Dyson equation. They found, under certain approximations, that a finite result ensues in the infrared limit. We find this conclusion to remain true with certain variations of these approximations, suggesting the finiteness of the result to be fairly robust.Comment: 6 pages, 4 figures, uses revtex