2,649 research outputs found
Efeito de períodos de estiagens artificiais durante estádios de desenvolvimento da planta no rendimento e qualidade da semente de soja (Glycine max. L. Merril).
Determinar o efeito de períodos de estilagem durante estádios de desenvolvimento da planta, no rendimento e qualidade da semente de duas cultivares de sojas: Bragg e Paraná.198
A symplectic acceleration method for the solution of the algebraic riccati equation on a parallel computer
AbstractWe give a cubic acceleration method for improving the current symplectic Jacobi-like algorithm for computing the Hamiltonian-Schur decomposition of a Hamiltonian matrix and finding the positive semidefinite solution of the Riccati equation. The acceleration method can speed up the rate of convergence at the end of the symplectic Jacobi-like process when the norm of the current strictly J-lower triangle has become sufficiently small; it has high parallelism and takes O(n) computational time when implemented on a mesh-connected n × n array processor system. A quantitative analysis of convergence and numerical comparisons of one Jacobi sweep versus one correction step are presented
Acceptance conditions in automated negotiation
In every negotiation with a deadline, one of the negotiating parties has to accept an offer to avoid a break off. A break off is usually an undesirable outcome for both parties, therefore it is important that a negotiator employs a proficient mechanism to decide under which conditions to accept. When designing such conditions one is faced with the acceptance dilemma: accepting the current offer may be suboptimal, as better offers may still be presented. On the other hand, accepting too late may prevent an agreement from being reached, resulting in a break off with no gain for either party. Motivated by the challenges of bilateral negotiations between automated agents and by the results and insights of the automated negotiating agents competition (ANAC), we classify and compare state-of-the-art generic acceptance conditions. We focus on decoupled acceptance conditions, i.e. conditions that do not depend on the bidding strategy that is used. We performed extensive experiments to compare the performance of acceptance conditions in combination with a broad range of bidding strategies and negotiation domains. Furthermore we propose new acceptance conditions and we demonstrate that they outperform the other conditions that we study. In particular, it is shown that they outperform the standard acceptance condition of comparing the current offer with the offer the agent is ready to send out. We also provide insight in to why some conditions work better than others and investigate correlations between the properties of the negotiation environment and the efficacy of acceptance condition
Asymptotic Behavior of Positive Solutions to Semilinear Elliptic Equations on Expanding Annuli
AbstractWe study the asymptotic behavior of positive solutions of the semilinear elliptic equation Δu + ƒ(u) = 0 in Ωa, u = 0 on ∂Ωa, where Ωa = {x ∈ of RN: a < |x| < a + 1} are expanding annuli as a → ∞, and ƒ is positive and superlinear at both 0 and ∞. We first show that there are a priori bounds for some positive solutions ua(x) as a → ∞. Then, if we fix any direction, after a suitable translation of ua the limiting solutions are non-negative solutions on the infinite strip. We can obtain more detailed descriptions of these limits if ua is radially symmetric, least-energy, or least-energy with a particular symmetry
Renormalization group approach to an Abelian sandpile model on planar lattices
One important step in the renormalization group (RG) approach to a lattice
sandpile model is the exact enumeration of all possible toppling processes of
sandpile dynamics inside a cell for RG transformations. Here we propose a
computer algorithm to carry out such exact enumeration for cells of planar
lattices in RG approach to Bak-Tang-Wiesenfeld sandpile model [Phys. Rev. Lett.
{\bf 59}, 381 (1987)] and consider both the reduced-high RG equations proposed
by Pietronero, Vespignani, and Zapperi (PVZ) [Phys. Rev. Lett. {\bf 72}, 1690
(1994)] and the real-height RG equations proposed by Ivashkevich [Phys. Rev.
Lett. {\bf 76}, 3368 (1996)]. Using this algorithm we are able to carry out RG
transformations more quickly with large cell size, e.g. cell for
the square (sq) lattice in PVZ RG equations, which is the largest cell size at
the present, and find some mistakes in a previous paper [Phys. Rev. E {\bf 51},
1711 (1995)]. For sq and plane triangular (pt) lattices, we obtain the only
attractive fixed point for each lattice and calculate the avalanche exponent
and the dynamical exponent . Our results suggest that the increase of
the cell size in the PVZ RG transformation does not lead to more accurate
results. The implication of such result is discussed.Comment: 29 pages, 6 figure
Longitudinal broadening of near side jets due to parton cascade
Longitudinal broadening along direction on near side in
two-dimensional () di-hadron correlation
distribution has been studied for central Au+Au collisions at =
200 GeV, within a dynamical multi-phase transport model. It was found that the
longitudinal broadening is generated by a longitudinal flow induced by strong
parton cascade in central Au+Au collisions, in comparison with p+p collisions
at = 200 GeV. The longitudinal broadening may shed light on the
information about strongly interacting partonic matter at RHIC.Comment: 5 pages, 4 figures; accepted by Eur. Phys. J.
On orbifold theory and N=2, D=5 gauged supergravity
We have studied the most general N=2 supergravity in five dimensions in
context with the orbifold theory based on . Various ways to
treat the supersymmetry with singular sources placed in orbifold fixed points
were proposed in past. Supersymmetric branes were consistently introduced in a
bulk where a gauged supergravity was present. In this paper we find that in the
supergravity with general gauging, the possibility to obtain a
supersymmetric brane world is constrained. Imposing the compatibility of
supersymmetry transformation rules with the orbifold condition, we find the
necessary and sufficient condition to obtain supersymmetric branes and bulk
independently. We comment that the same condition guarantees naturally the
presence of singular BPS solutions.Comment: 16 page
Classification and nondegeneracy of Toda system with singular sources
We consider the following Toda system \Delta u_i + \D \sum_{j = 1}^n
a_{ij}e^{u_j} = 4\pi\gamma_{i}\delta_{0} \text{in}\mathbb R^2, \int_{\mathbb
R^2}e^{u_i} dx -1\delta_0a_{ij}\gamma_i=0\forall \;1\leq i\leq n\gamma_i+\gamma_{i+1}+...+\gamma_j \notin \mathbb Z1\leq i\leq
j\leq nu_i$ is \textit{radially symmetric} w.r.t. 0.
(iii) We prove that the linearized equation at any solution is
\textit{non-degenerate}. These are fundamental results in order to understand
the bubbling behavior of the Toda system.Comment: 28 page
Peroxisome proliferator-activated receptor -β/δ, -γ Agonists and resveratrol modulate hypoxia induced changes in nuclear receptor activators of muscle oxidative metabolism
PPAR-α, PPAR-β, and PPAR-γ, and RXR in conjunction with PGC-1α and SIRT1, activate oxidative metabolism genes determining insulin sensitivity. In utero, hypoxia is commonly observed in Intrauterine Growth Restriction (IUGR), and reduced insulin sensitivity is often observed in these infants as adults. We sought to investigate how changes in oxygen tension might directly impact muscle PPAR regulation of oxidative genes. Following eight days in culture at 1 oxygen, C2C12 muscle myoblasts displayed a reduction of PGC-1α, PPAR-α, and RXR-α mRNA, as well as CPT-1b and UCP-2 mRNA. SIRT1 and PGC-1α protein was reduced, and PPAR-γ protein increased. The addition of a PPAR-β agonist (L165,041) for the final 24 hours of 1 treatment resulted in increased levels of UCP-2 mRNA and protein whereas Rosiglitazone induced SIRT1, PGC-1α, RXR-α, PPAR-γ, CPT-1b, and UCP-2 mRNA and SIRT1 protein. Under hypoxia, Resveratrol induced SIRT1, RXR-, PPAR- mRNA, and PPAR- and UCP-2 protein. These findings demonstrate that hypoxia alters the components of the PPAR pathway involved in muscle fatty acid oxidative gene transcription and translation. These results have implications for understanding selective hypoxia adaptation and how it might impact long-term muscle oxidative metabolism and insulin sensitivity. Copyright © 2010 Timothy R. H. Regnault et al
Black Hole Statistics from Holography
We study the microstates of the ``small'' black hole in the \half-BPS
sector of AdS, the superstar of Myers and Tafjord, using the
powerful holographic description provided by LLM. The system demonstrates the
inherently statistical nature of black holes, with the geometry of Myer and
Tafjord emerging only after averaging over an ensemble of geometries. The
individual microstate geometries differ in the highly non-trivial topology of a
quantum foam at their core, and the entropy can be understood as a partition of
units of flux among 5-cycles, as required by flux quantization. While the
system offers confirmation of the most controversial aspect of Mathur and
Lunin's recent ``fuzzball'' proposal, we see signs of a discrepancy in
interpreting its details.Comment: 21 pages, 4 figures; References adde
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