DETERMINATION of THE INDIRECT ORIENTATION of ORBITAL PUSHBROOM IMAGES USING CONTROL STRAIGHT LINES

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Induction of apoptosis in A549 pulmonary cells by two Paracoccidioides brasiliensis samples

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Acute 2,4-dichlorophenoxyacetic acid intoxication in broiler chicks

The acute toxicity of 2,4-dichlorophenoxyacetic acid (2,4-D), a herbicide, was studied in chicks dosed with 100, 300, 500, or 600 mg 2,4-D/kg BW, by the oral route. Clinical, laboratory, and histopathological methods were used as indicators of toxicity. After acute exposure, the herbicide decreased motor activity and induced muscular weakness and motor incoordination; decreased weight gain; increased serum creatine kinase (CK) and alkaline phosphatase (AP) activities and serum uric acid (UA), creatinine (CR), and total proteins (TP) levels; and did not change serum aspartate aminotransferase (AST) or alanine aminotransferase (ALT) activities. These changes were time-and dose-dependent and reversible. The LD50 (lethal dose 50%) calculated for oral 2,4-D in chicks was 420 mg/kg BW (385 to 483). Chromatographic analysis of the serum of the intoxicated chicks showed the presence of the herbicide; the amount found was dose-and time-dependent, increasing from 2 to 8 h after exposure and decreasing afterwards. Histopathological post-mortem studies conducted on intoxicated chicks showed hepatic (vacuolar degeneration of the hepatocytes), renal (tubular nephrosis), and intestinal (hemorragic) lesions. Taken together, the observed alterations mainly reflected kidney and muscle tissue damage, although hepatic toxicity may also have occurred after acute 2,4-D intoxication.

Um estudo na teoria do movimento brownianno com viscosidade variável

In this work we investigate the stochastic behavior of a large class of systems with variable damping which are described by a time-dependent Lagrangian. Our stochastic approach is based on the Langevin treatment describing the motion of a classical Brownian particle of mass m. Two situations of physical interest are considered. In the first one, we discuss in detail an application of the standard Langevin treatment (white noise) for the variable damping system. In the second one, a more general viewpoint is adopted by assuming a given expression to the so-called collored noise. For both cases, the basic diffententiaql equations are analytically solved and al the quantities physically relevant are explicitly determined. The results depend on an arbitrary q parameter measuring how the behavior of the system departs from the standard brownian particle with constant viscosity. Several types of sthocastic behavior (superdiffusive and subdiffusive) are obteinded when the free pamameter varies continuosly. However, all the results of the conventional Langevin approach with constant damping are recovered in the limit q = 1

Deposição de A/N por sputtering não reativo

In this work we deposit via non-reactive magnetron sputtering of radio-frequency nanofilmes of nitreto of aluminum(AlN). The nanofilms aluminum nitride are semiconductors materials with high thermal conductivity, high melting point, piezoelectricity and wide band gap (6, 2 eV) with hexagonal wurtzite crystal structure, belonging to the group of new materials called III-V nitrides in which together with the gallium nitride and indium nitride have attracted much interest because they have physical and chemical properties relevant to new technological applications, mainly in microelectronic and optoelectronic devices. Three groups were deposited with thicknesses nanofilms time dependent on two substrates (glass and silicon) at a temperature of 25 ° C. The nanofilms AlN were characterized using three techniques, X-ray diffraction, Raman spectroscopy and atomic force microscopy (AFM), examined the morphology of these. Through the analysis of X-rays get the thickness of each sample with its corresponding deposition rate. The analysis of X-rays also revealed that nanofilms are not crystalline, showing the amorphous character of the samples. The results obtained by the technique, atomic force microscopy (AFM) agree with those obtained using the technique of X-rays. Characterization by Raman spectroscopy revealed the existence of active modes characteristic of AlN in the samples

Soluções cosmológicas e locais para uma eletrodinâmica modificada

The present work investigates some consequences that arise from the use of a modifed lagrangean for the eletromagnetic feld in two diferent contexts: a spatially homogeneous and isotropic universe whose dynamics is driven by a magnetic feld plus a cosmological parameter A, and the problem of a static and charged point mass (charged black hole). In the cosmological case, three diferent general solutions were derived. The first, with a null cosmological parameter A, generalizes a particular solution obtained by Novello et al [gr-qc/9806076]. The second one admits a constant A and the third one allows A to be a time-dependent parameter that sustains a constant magnetic feld. The first two solutions are non-singular and exhibit in ationary periods. The third case studied shows an in ationary dynamics except for a short period of time. As for the problem of a charged point mass, the solutions of the Einstein-Maxwell equations are obtained and compared with the standard Reissner-Nordstrom solution. Contrary to what happens in the cosmological case, the physical singularity is not removed

Setor escuro do universo: uma análise termodinâmica

Significant observational effort has been directed to unveiling the nature of the so-called dark energy. However, given the large number of theoretical possibilities, it is possible that this a task cannot be based only on observational data. In this thesis we investigate the dark energy via a thermodynamics approach, i.e., we discuss some thermodynamic properties of this energy component assuming a general time-dependent equation-of-state (EoS) parameter w(a) = w0 + waf(a), where w0 and wa are constants and f(a) may assume different forms. We show that very restrictive bounds can be placed on the w0 - wa space when current observational data are combined with the thermodynamic constraints derived. Moreover, we include a non-zero chemical potential μ and a varying EoS parameter of the type ω(a) = ω0 + F(a), therefore more general, in this thermodynamical description. We derive generalized expressions for the entropy density and chemical potential, noting that the dark energy temperature T and μ evolve in the same way in the course of the cosmic expansion. The positiveness of entropy S is used to impose thermodynamic bounds on the EoS parameter ω(a). In particular, we find that a phantom-like behavior ω(a) < −1 is allowed only when the chemical potential is a negative quantity (μ < 0). Thermodynamically speaking, a complete treatment has been proposed, when we address the interaction between matter and energy dark

Processos difusivos generalizados

We investigate several diffusion equations which extend the usual one by considering the presence of nonlinear terms or a memory effect on the diffusive term. We also considered a spatial time dependent diffusion coefficient. For these equations we have obtained a new classes of solutions and studied the connection of them with the anomalous diffusion process. We start by considering a nonlinear diffusion equation with a spatial time dependent diffusion coefficient. The solutions obtained for this case generalize the usual one and can be expressed in terms of the q-exponential and q-logarithm functions present in the generalized thermostatistics context (Tsallis formalism). After, a nonlinear external force is considered. For this case the solutions can be also expressed in terms of the q-exponential and q-logarithm functions. However, by a suitable choice of the nonlinear external force, we may have an exponential behavior, suggesting a connection with standard thermostatistics. This fact reveals that these solutions may present an anomalous relaxation process and then, reach an equilibrium state of the kind Boltzmann- Gibbs. Next, we investigate a nonmarkovian linear diffusion equation that presents a kernel leading to the anomalous diffusive process. Particularly, our first choice leads to both a the usual behavior and anomalous behavior obtained through a fractionalderivative equation. The results obtained, within this context, correspond to a change in the waiting-time distribution for jumps in the formalism of random walks. These modifications had direct influence in the solutions, that turned out to be expressed in terms of the Mittag-Leffler or H of Fox functions. In this way, the second moment associated to these distributions led to an anomalous spread of the distribution, in contrast to the usual situation where one finds a linear increase with time

Influence of visual information on optimal obstacle crossing

Human motion seems to be guided by some optimal principles. In general, it is assumed that human walking is generated with minimal energy consumption. However, in the presence of disturbances during gait, there is a trade-off between stability (avoiding a fall) and energy-consumption. This work analyses the obstacle-crossing with the leading foot. It was hypothesized that energy-saving mechanisms during obstacle-crossing are modulated by the requirement to avoid a fall using the available sensory information, particularly, by vision. A total of fourteen subjects, seven with no visual impairment and seven blind, walked along a 5 meter flat pathway with an obstacle of 0.26 m height located at 3 m from the starting point. The seven subjects with normal vision crossed the obstacle successfully 30 times in two conditions: blindfolded and with normal vision. The seven blind subjects did the same 30 times. The motion of the leading limb was recorded by video at 60 Hz. There were markers placed on the subject's hip, knee, ankle, rear foot, and forefoot. The motion data were filtered with a fourth order Butterworth filter with a cut-off frequency of 4 Hz. The following variables were calculated: horizontal distance between the leading foot and the obstacle at toe-off prior to (DHPO) and after (DHOP) crossing, minimal vertical height from the foot to the obstacle (DVPO), average step velocity (VELOm). The segmental energies were also calculated and the work consumed by the leading limb during the crossing obstacle was computed for each trial. A statistical analysis repeated-measures ANOVA was conducted on these dependent variables revealing significant differences between the vision and non-vision conditions in healthy subjects. In addition, there were no significant differences between the blind and people with vision blindfolded. These results indicate that vision is crucial to determine the optimal trade-off between energy consumption and avoiding a trip during obstacle crossing.