Bioinformática: formação acadêmica e plataformas com softwares e ferramentas.

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Aerodynamic performance of a free-flying dragonfly—A span-resolved investigation

We present a quantitative characterization of the unsteady aerodynamic features of a live, free-flying dragonfly under a well-established flight condition. In particular, our investigations cover the span-wise features of vortex interactions between the fore- and hind-pairs of wings that could be a distinctive feature of a high aspect ratio tandem flapping wing pair. Flapping kinematics and dynamic wing-shape deformation of a dragonfly were measured by tracking painted landmarks on the wings. Using it as the input, computational fluid dynamics analyses were conducted, complemented with time-resolved particle image velocimetry flow measurements to better understand the aerodynamics associated with a dragonfly. The results show that the flow structures around hindwing’s inner region are influenced by forewing’s leading edge vortex, while those around hindwing’s outer region are more influenced by forewing’s shed trailing edge vortex. Using a span-resolved approach, we found that the forewing–hindwing interactions affect the horizontal force (thrust) generation of the hindwing most prominently and the modulation of the force generation is distributed evenly around the midspan. Compared to operating in isolation, the thrust of the hindwing is largely increased during upstroke, albeit the drag is also slightly increased during the downstroke. The vertical force generation is moderately affected by the forewing–hindwing interactions and the modulation takes place in the outer 40% of the hindwing span during the downstroke and in the inner 60% of the span during the upstroke

Pressure-induced polarization reversal in multiferroic YMn2O5YMn_2O_5

The low-temperature ferroelectric polarization of multiferroic $YMn_2O_5$ is completely reversed at a critical pressure of 10 kbar and the phase transition from the incommensurate to the commensurate magnetic phase is induced by pressures above 14 kbar. The high-pressure data correlate with thermal expansion measurements indicating a significant lattice strain at the low-temperature transition into the incommensurate phase. The results support the exchange striction model for the ferroelectricity in multiferroic $RMn_2O_5$ compounds and they show the importance of magnetic frustration as well as the spin-lattice coupling

Anotação funcional de sequências com BLAST2GO.

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O papel das mutações na compreensão da genética do milho.

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Chromosomal control of non-gliadin proteins from the 70% ethanol extract of wheat endosperm

The non-gliadin fraction of the 70% ethanol extracts of compensated nulli-tetrasomics and ditelosomics of Triticum aestivum cv. Chinese Spring has been analyzed by combined electrofocusing and electrophoresis. Seventeen of the 21 protein map components of the euploid have been ascribed to eight chromosomes: 4A, 3BS, 6BS, 7BS, 3D, 4D, 5D and 7DS. The relationship of the different map components with other proteins previously associated with the same chromosomes is discusse

Information theory explanation of the fluctuation theorem, maximum entropy production and self-organized criticality in non-equilibrium stationary states

Jaynes' information theory formalism of statistical mechanics is applied to the stationary states of open, non-equilibrium systems. The key result is the construction of the probability distribution for the underlying microscopic phase space trajectories. Three consequences of this result are then derived : the fluctuation theorem, the principle of maximum entropy production, and the emergence of self-organized criticality for flux-driven systems in the slowly-driven limit. The accumulating empirical evidence for these results lends support to Jaynes' formalism as a common predictive framework for equilibrium and non-equilibrium statistical mechanics.Comment: 21 pages, 0 figures, minor modifications, version to appear in J. Phys. A. (2003

Counting RNAseq reads: which way is better?

In this work we show the variation of results we?ve found while working with ~1 billion Illumina reads from drought tolerant Sorghum bicolor genotype in the presence and absence of the stress and compared results found for key genes already characterized.Pôster N101

Optical extinction due to intrinsic structural variations of photonic crystals

Unavoidable variations in size and position of the building blocks of photonic crystals cause light scattering and extinction of coherent beams. We present a new model for both 2 and 3-dimensional photonic crystals that relates the extinction length to the magnitude of the variations. The predicted lengths agree well with our new experiments on high-quality opals and inverse opals, and with literature data analyzed by us. As a result, control over photons is limited to distances up to 50 lattice parameters ($\sim 15 \mu$m) in state-of-the-art structures, thereby impeding large-scale applications such as integrated circuits. Conversely, scattering in photonic crystals may lead to novel physics such as Anderson localization and non-classical diffusion.Comment: 10 pages, 3 figures. Changes include: added Lagendijk as author; simplified and generalized the tex

Evaluation of lubrication force on colliding particles for DEM simulation of fluidized beds

"Lubrication force" arises from hydrodynamic pressure in the interstitial fluid being squeezed out from the space between two solid surfaces. In the previous DEM simulations of gas-solid flows this force has not been explicitly taken into account since it may introduce the famous "Stokes Paradox", which postulates that: Two solid surfaces can never make contact in a finite time in a viscous fluid due to the infinite "lubrication force" when the distance approaches zero at the last moment of contact. It is easy to imagine that lubrication effect is critical in liquid-solid systems, but it may not be negligible even in gas-solid systems of light and small particles. Although the lubrication theory has been well established in liquid-solid systems, its application in gas-solid systems should be used with caution because the assumptions adopted in the classical lubrication theory are only valid for highly viscous systems. In the present study, these assumptions are examined and semi-theoretical expressions for lubrication force are proposed based on numerical analysis. The paradox of contactless collision due to infinite lubrication force is effectively avoided by considering surface roughness, non-continuum fluid effect and van der Waals force. The coefficient of restitution is defined as a criterion for evaluating the significance of lubrication effect in collisions of particles in fluidized beds. For demonstration the lubrication effect was evaluated for beds of FCC particles and GB (glass beads), with diameters ranging from 25 to 100 μm and initial approaching velocity from umf to ut. The calculated restitution coefficient ranged from 0 to nearly 1 and clearly showed that lubrication force plays a significant role during a close encounter of two particles even in gas-solid systems