Recomendações para prevenção e controle de bicheiras em bezerros no Pantanal.

Com quase 50 milhões de cabeças, os estados de Mato Grosso do Sul e Mato Grosso possuem os maiores rebanhos bovinos do país. Embora a maior parte destes animais esteja distribuída no planalto, cerca de 3,5milhões de cabeças são mantidas na planície pantaneira. A bovinocultura tradicional no Pantanal se caracteriza por uma pecuária de corte extensiva, calcada em pastagens nativas e com ênfase na fase de cria e, secundariamente, de recria. Este artigo apresenta uma breve revisão sobre o problema das bicheiras (miíases) e recomendações técnicas enfocando a prevenção e tratamento de miíases umbilicais em bezerros recém-nascidos.bitstream/item/79511/1/COT35.pd

Mutucas (Diptera: Tabanidae) do Pantanal: abundância relativa e sazonalidade na sub-região da Nhecolândia.

De junho/92 a maio/94, capturas de mutucas foram realizadas mensalmente em eqüino e utilizando armadilhas do tipo ?canopy?, na fazenda Nhumirim, subregião da Nhecolândia, Pantanal sul-mato-grossense. Capturas no eqüino foram realizadas do crepúsculo matutino ao vespertino, com o auxílio de redes entomológicas, em ambientes de campo e cerradão (1 dia/ambiente/mês), durante o primeiro ano do estudo. Capturas com armadilhas foram realizadas nos mesmos ambientes (10 dias/ambiente/mês), por dois anos. Foram capturadas 6.274 mutucas ao longo do estudo, pertencentes a 25 espécies, 13 gêneros e 3 subfamílias. A espécies mais abundantes foram Tabanus importunus (44,04%), Tabanus occidentalis (15,95%), Tabanus claripennis (9,98%) e Lepiselaga crassipes (7,60%). Apesar do menor esforço de captura, as coletas no eqüino foram mais eficientes que as realizadas com armadilhas, totalizando 3.442 (54,9%) e 2.832 (45,1%) mutucas, respectivamente. Picos populacionais foram observados próximos ao início do período chuvoso, geralmente entre setembro e novembro (primavera). Entretanto, as mutucas foram relativamente abundantes também durante parte do verão. Os resultados obtidos nestes estudos indicam que mutucas são mais abundantes durante a época chuvosa, particularmente na primavera, considerada a época de maior risco de transmissão mecânica de patógenos por estes vetores.bitstream/item/37402/1/BP48.pd

Sandpile model on an optimized scale-free network on Euclidean space

Deterministic sandpile models are studied on a cost optimized Barab\'asi-Albert (BA) scale-free network whose nodes are the sites of a square lattice. For the optimized BA network, the sandpile model has the same critical behaviour as the BTW sandpile, whereas for the un-optimized BA network the critical behaviour is mean-field like.Comment: Five pages, four figure

Tribological variable-friction coefficient models for the simulation of dense suspensions of rough polydisperse particles

The rheology of concentrated suspensions of particles is complex and typically exhibits a shear-thickening behavior in the case of repulsive interactions. Despite the recent interest arisen, the causes of the shear-thickening remain unclear. Frictional contacts have been able to explain the discontinuous shear thickening in simulations. However, the interparticle friction coefficient is considered to be constant in most simulations and theoretical works reported to date despite the fact that tribological experiments demonstrate that the friction coefficient can not only be constant (boundary regime) but also decrease (mixed regime) or even increase (full-film lubrication regime), depending on the normal force and the relative velocity between the particles and the interstitial liquid between them. Interestingly, the transition between the boundary regime and the full-lubrication regime is governed by the particle average roughness. Particle-level simulations of suspensions of hard spheres were carried out using short-range lubrication and roughness-dependent frictional forces describing the full Stribeck curve. Suspensions with different particle's roughness were simulated to show that the particle roughness is a key factor in the shear-thickening behavior; for sufficiently rough particles, the suspension exhibits a remarkable shear-thickening, while for sufficiently smooth particles, the discontinuous shear-thickening disappears

Beyond quantum mechanics? Hunting the 'impossible' atoms (Pauli Exclusion Principle violation and spontaneous collapse of the wave function at test)

The development of mathematically complete and consistent models solving the so-called "measurement problem", strongly renewed the interest of the scientific community for the foundations of quantum mechanics, among these the Dynamical Reduction Models posses the unique characteristic to be experimentally testable. In the first part of the paper an upper limit on the reduction rate parameter of such models will be obtained, based on the analysis of the X-ray spectrum emitted by an isolated slab of germanium and measured by the IGEX experiment. The second part of the paper is devoted to present the results of the VIP (Violation of the Pauli exclusion principle) experiment and to describe its recent upgrade. The VIP experiment established a limit on the probability that the Pauli Exclusion Principle (PEP) is violated by electrons, using the very clean method of searching for PEP forbidden atomic transitions in copper

Gravitational Collapse in Turbulent Molecular Clouds. I. Gasdynamical Turbulence

Observed molecular clouds often appear to have very low star formation efficiencies and lifetimes an order of magnitude longer than their free-fall times. Their support is attributed to the random supersonic motions observed in them. We study the support of molecular clouds against gravitational collapse by supersonic, gas dynamical turbulence using direct numerical simulation. Computations with two different algorithms are compared: a particle-based, Lagrangian method (SPH), and a grid-based, Eulerian, second-order method (ZEUS). The effects of both algorithm and resolution can be studied with this method. We find that, under typical molecular cloud conditions, global collapse can indeed be prevented, but density enhancements caused by strong shocks nevertheless become gravitationally unstable and collapse into dense cores and, presumably, stars. The occurance and efficiency of local collapse decreases as the driving wave length decreases and the driving strength increases. It appears that local collapse can only be prevented entirely with unrealistically short wave length driving, but observed core formation rates can be reproduced with more realistic driving. At high collapse rates, cores are formed on short time scales in coherent structures with high efficiency, while at low collapse rates they are scattered randomly throughout the region and exhibit considerable age spread. We suggest that this naturally explains the observed distinction between isolated and clustered star formation.Comment: Minor revisions in response to referee, thirteen figures, accepted to Astrophys.

Structure of a large social network

We study a social network consisting of over $10^4$ individuals, with a degree distribution exhibiting two power scaling regimes separated by a critical degree $k_{\rm crit}$, and a power law relation between degree and local clustering. We introduce a growing random model based on a local interaction mechanism that reproduces all of the observed scaling features and their exponents. Our results lend strong support to the idea that several very different networks are simultenously present in the human social network, and these need to be taken into account for successful modeling.Comment: 5 pages, 5 figure

Spontaneously emitted X-rays: an experimental signature of the dynamical reduction models

We present the idea of searching for X-rays as a signature of the mechanism inducing the spontaneous collapse of the wave function. Such a signal is predicted by the continuous spontaneous localization theories, which are solving the "measurement problem" by modifying the Schrodinger equation. We will show some encouraging preliminary results and discuss future plans and strategy.Comment: to be published in Foundation of Physics 201

Instability of LBV-stars against radial oscillations

In this study we consider the nonlinear radial oscillations exciting in LBV--stars with effective temperatures 1.5e4 K <= Teff <= 3e4 K, bolometric luminosities 1.2e6 L_odot <= L <= 1.9e6 L_odot and masses 35.7 M_odot <= M <= 49.1 M_odot. Hydrodynamic computations were carried out with initial conditions obtained from evolutionary sequences of population I stars (X=0.7, Z=0.02) with initial masses from 70M_odot to 90 M_odot. All hydrodynamical models show instability against radial oscillations with amplitude growth time comparable with dynamical time scale of the star. Radial oscillations exist in the form of nonlinear running waves propagating from the boundary of the compact core to the upper boundary of the hydrodynamical model. The velocity amplitude of outer layers is of several hundreds of km/s while the bolometric light amplitude does not exceed 0.2 mag. Stellar oscillations are not driven by the kappa-mechanism and are due to the instability of the gas with adiabatic exponent close to the critical value Gamma_1 = 4/3 due to the large contribution of radiation in the total pressure. The range of the light variation periods (6 day <= P <= 31 day) of hydrodynamical models agrees with periods of microvariability observed in LBV--stars.Comment: 14 pages, 5 figures, submitted to Astronomy Letter