No-horizon theorem for spacetimes with spacelike G1 isometry groups

We consider four-dimensional spacetimes $(M,{\mathbf g})$ which obey the Einstein equations ${\mathbf G}={\mathbf T}$, and admit a global spacelike $G_{1}={\mathbb R}$ isometry group. By means of dimensional reduction and local analyis on the reduced (2+1) spacetime, we obtain a sufficient condition on ${\mathbf T}$ which guarantees that $(M,{\mathbf g})$ cannot contain apparent horizons. Given any (3+1) spacetime with spacelike translational isometry, the no-horizon condition can be readily tested without the need for dimensional reduction. This provides thus a useful and encompassing apparent horizon test for $G_{1}$-symmetric spacetimes. We argue that this adds further evidence towards the validity of the hoop conjecture, and signals possible violations of strong cosmic censorship.Comment: 8 pages, LaTeX, uses IOP package; published in Class. Quantum Gra

Spin torque ferromagnetic resonance with magnetic field modulation

We demonstrate a technique of broadband spin torque ferromagnetic resonance (ST-FMR) with magnetic field modulation for measurements of spin wave properties in magnetic nanostructures. This technique gives great improvement in sensitivity over the conventional ST-FMR measurements, and application of this technique to nanoscale magnetic tunnel junctions (MTJs) reveals a rich spectrum of standing spin wave eigenmodes. Comparison of the ST-FMR measurements with micromagnetic simulations of the spin wave spectrum allows us to explain the character of low-frequency magnetic excitations in nanoscale MTJs.Comment: Also see: http://faculty.sites.uci.edu/krivorotovgroup

Planejamento e reengenharia de sistemas de informação com foco no diagrama de implantação.

Este artigo apresenta o processo de documentação da segunda versão do sistema Agritempo, relatando mais especificamente o uso de um diagrama específico da UML com impacto positivo no processo de desenvolvimento e manutenção do sistema

Effect of a new pyrimidine derivative, 2-(4´-aminobenzenamine)-pyrimidine, isolated from the bulbs of Autonoë madeirensis, in the rat vas deferens contractility.

Comunicação oral sob forma de PainelAutonoë madeirensis (Menezes) Speta is a Hyacinthaceae endemic from the Madeira Archipelago (Portugal). From its bulbs we isolated a new compound: 2-(4-aminobenzenamine)-pyrimidine [1]. As pyrimidines have important effects in smooth muscle contraction we investigated the effect of the ethanolic extract and the effect of compound [1] in the rat vas deferens contractility. Compound [1] was obtained from fresh bulbs extracted with ethanol. The ethanolic residue was subjected to fractionation yielding the pure compound [1] identified by spectral data. Using isolated rat vas deferens, dose-response curves were obtained with phenylephrine (Phe) (1.0–32.0 µM) in the absence and in the presence of the ethanolic extract and in the presence of compound [1]. Both ethanolic extract and compound [1] in concentrations devoid of effect shifted to the right the concentration-response curve of Phe, without changing the maximal effect. EC50 values for Phe increased in the presence of compound [1] (5 µM, 50 µM and 100 µM) and were respectively 3 ± 0.8 µM, 4.6 ± 0.7 µM and 3.9 ± 0.6 µM. These values are statistically different from EC50 values obtained in the same vas in control conditions which were respectively 2.2 ±0.8 µM, 1.7 ± 0.2 µM and 1.5 ± 0.1 µM. In the presence of the extract (0.3 and 1.2 mg/ml) the EC50 values for Phe increased significantly and were respectively 4.1 ± 0.8 µM versus 2.2 ± 0.3 µM in control and 4.6 ± 0.9 µM versus 1.7 ± 0.2 µM in control. These results suggest that compound [1] antagonises the α-adrenergic effects of Phe in the rat vas deferens.The Unit of Pharmacology and Pharmacotoxicology, Faculty of Pharmacy, University of Lisbon supported this research

Ranking and clustering of nodes in networks with smart teleportation

Random teleportation is a necessary evil for ranking and clustering directed networks based on random walks. Teleportation enables ergodic solutions, but the solutions must necessarily depend on the exact implementation and parametrization of the teleportation. For example, in the commonly used PageRank algorithm, the teleportation rate must trade off a heavily biased solution with a uniform solution. Here we show that teleportation to links rather than nodes enables a much smoother trade-off and effectively more robust results. We also show that, by not recording the teleportation steps of the random walker, we can further reduce the effect of teleportation with dramatic effects on clustering.Comment: 10 pages, 7 figure

Nuclear shadowing from exclusive quarkonium photoproduction at the BNL RHIC and CERN LHC

The photonuclear production of vector mesons in ultraperipheral heavy ion collisions is investigated within the collinear approach using different parameterizations for the nuclear gluon distribution. The integrated cross section and the rapidity distribution for the $AA \to V AA$ ($V = J/\Psi, \Upsilon$) process are computed for energies of RHIC and LHC. A comparison with the recent PHENIX data on coherent production of $J/\Psi$ mesons is also presented. We demonstrate that the study of the exclusive quarkonium photoproduction can be used to constrain the nuclear effects in the gluon distribution.Comment: 8 pages, 4 figures, 2 tables. Version to be published in Physical Review

Nonuniform autonomous one-dimensional exclusion nearest-neighbor reaction-diffusion models

The most general nonuniform reaction-diffusion models on a one-dimensional lattice with boundaries, for which the time evolution equations of corre- lation functions are closed, are considered. A transfer matrix method is used to find the static solution. It is seen that this transfer matrix can be obtained in a closed form, if the reaction rates satisfy certain conditions. We call such models superautonomous. Possible static phase transitions of such models are investigated. At the end, as an example of superau- tonomous models, a nonuniform voter model is introduced, and solved explicitly.Comment: 14 page

Phase diagram of a random-anisotropy mixed-spin Ising model

We investigate the phase diagram of a mixed spin-1/2--spin-1 Ising system in the presence of quenched disordered anisotropy. We carry out a mean-field and a standard self-consistent Bethe--Peierls calculation. Depending on the amount of disorder, there appear novel transition lines and multicritical points. Also, we report some connections with a percolation problem and an exact result in one dimension.Comment: 8 pages, 4 figures, accepted for publication in Physical Review

Ergonomic design intervention in a coating production area

The aim of this study is to redesign two workstations in a PVD coating production area, considering productivity and ergonomic aspects. Through the elimination of wastes such as unnecessary movements and transportations and by reducing the awkward postures as arm flexion larger than 45º, the productivity in the loading and unloading workstations increased 9% and 5%, respectively, and the ergonomic risk was improved from medium to acceptable. RULA was the chosen method to evaluate the ergonomic situation and anthropometric studies were performed to find the ideal ergonomic solution. This study shows the importance to consider ergonomic conditions when designing or redesigning a workstation in order to get effective productivity improvements.(undefined)info:eu-repo/semantics/publishedVersio

Seleção preliminar de estirpes de rizóbios para inoculação em feijoeiro comum (Phaseolus vulgaris L.)

bitstream/item/66227/1/31297.pdfOrganizado por: Alberto Feiden, Milton Parron Padovan, Adalgiza Inês Campolim, Aurélio Vinícius Borsato, Ivo de Sá Motta, João Batista Catto, Tércio Jacques Fehlauer