Navega??o de m?ltiplos agentes sobre superf?cies arbitr?rias utilizando planariza??o din?mica

Path planning of multiple agents on arbitrary surfaces is a recent research topic. The quality of the paths generated to arbitrary surface is poor compared to method proposed to planar surfaces. A major limitation to improve the quality is related to the computational cost of computing distances over arbitrary surface. Traditional path planning algorithms designed to planar surface use Euclidian distance with has constant computational cost, in the other hand, arbitrary surfaces require Geodesic distances with in turn has a considerable higher computational cost. This project proposes novel dynamic planarization around each agent with will allow the use of Eucledian distance during the local navigation, that way, classic path planning algorithms designed for planar surface can be used over arbitrary surface. The main benefit is the increased quality of paths for agents. The proposed solution uses geodesic distance in the global navigation, responsible for defining the initial path. However, for the local navigation, or obstacle avoidance, our solution allows the use of classic techniques. To allow the use of these methods we propose a planarization of the surface adjacent to the agent in order to replace the use of geodesic distance with Euclidean distance in the local navigation. Additionally, the algorithm is massively parallel and implemented in the CPU and GPU to explore the best features of each.Navega??o de m?ltiplos agentes em superf?cies arbitr?rias ? um t?pico de pesquisa recente que tem atra?do crescente aten??o, entretanto, estes trabalhos n?o s?o capazes de realizar a navega- ??o em tempo real com a mesma qualidade dos trabalhos focados em superf?cies planares. Um dos principais fatores limitantes ? o custo computacional do c?lculo de dist?ncia entre dois pontos sobre uma superf?cie arbitr?ria, o que em superf?cies planares pode ser realizado em tempo constante atrav?s do c?lculo de dist?ncia euclidiana. Neste trabalho ? proposta uma abordagem para realizar a navega??o de m?ltiplos agentes sobre superf?cies arbitr?rias, e ao contr?rio dos trabalhos anteriores, permitindo a utiliza??o de t?cnicas de navega??o sobre superf?cies planares, por exemplo, Reciprocal Velocity Obstacles. A solu??o proposta utiliza o c?lculo da dist?ncia geod?sica na navega??o global, respons?vel pela defini??o do caminho inicial. Para o desvio dos obst?culos din?micos s?o utilizadas t?cnicas consolidadas, criadas para superf?cies planares, com comprovada qualidade. Para permitir a utiliza??o desses m?todos ? proposta uma planariza??o da superf?cie pr?xima do agente de modo a substituir o uso de dist?ncia geod?sica por dist?ncia euclidiana na navega??o local. Al?m disso, ? implementado um algoritmo h?brido CPU/GPU e assim explorando as melhores qualidades de cada processador

First Results from Pb+Pb collisions at the LHC

At the end of 2010, the CERN Large Hadron Collider started operation with heavy ion beams, colliding lead nuclei at a centre-of-mass energy of 2.76 TeV/nucleon and opening a new era in ultra-relativistic heavy ion physics at energies exceeding previous accelerators by more than an order of magnitude. This review summarizes the results from the first year of heavy ion physics at LHC obtained by the three experiments participating in the heavy ion program, ALICE, ATLAS, and CMS.Comment: To appear in Annual Review of Nuclear and Particle Scienc

N=2 Boundary conditions for non-linear sigma models and Landau-Ginzburg models

We study N=2 nonlinear two dimensional sigma models with boundaries and their massive generalizations (the Landau-Ginzburg models). These models are defined over either Kahler or bihermitian target space manifolds. We determine the most general local N=2 superconformal boundary conditions (D-branes) for these sigma models. In the Kahler case we reproduce the known results in a systematic fashion including interesting results concerning the coisotropic A-type branes. We further analyse the N=2 superconformal boundary conditions for sigma models defined over a bihermitian manifold with torsion. We interpret the boundary conditions in terms of different types of submanifolds of the target space. We point out how the open sigma models correspond to new types of target space geometry. For the massive Landau-Ginzburg models (both Kahler and bihermitian) we discuss an important class of supersymmetric boundary conditions which admits a nice geometrical interpretation.Comment: 48 pages, latex, references and minor comments added, the version to appear in JHE

Light emission from a scanning tunneling microscope: Fully retarded calculation

The light emission rate from a scanning tunneling microscope (STM) scanning a noble metal surface is calculated taking retardation effects into account. As in our previous, non-retarded theory [Johansson, Monreal, and Apell, Phys. Rev. B 42, 9210 (1990)], the STM tip is modeled by a sphere, and the dielectric properties of tip and sample are described by experimentally measured dielectric functions. The calculations are based on exact diffraction theory through the vector equivalent of the Kirchoff integral. The present results are qualitatively similar to those of the non-retarded calculations. The light emission spectra have pronounced resonance peaks due to the formation of a tip-induced plasmon mode localized to the cavity between the tip and the sample. At a quantitative level, the effects of retardation are rather small as long as the sample material is Au or Cu, and the tip consists of W or Ir. However, for Ag samples, in which the resistive losses are smaller, the inclusion of retardation effects in the calculation leads to larger changes: the resonance energy decreases by 0.2-0.3 eV, and the resonance broadens. These changes improve the agreement with experiment. For a Ag sample and an Ir tip, the quantum efficiency is $\approx$ 10$^{-4}$ emitted photons in the visible frequency range per tunneling electron. A study of the energy dissipation into the tip and sample shows that in total about 1 % of the electrons undergo inelastic processes while tunneling.Comment: 16 pages, 10 figures (1 ps, 9 tex, automatically included); To appear in Phys. Rev. B (15 October 1998

Towards the Rosetta Stone of planet formation

Transiting exoplanets (TEPs) observed just about 10 Myrs after formation of their host systems may serve as the Rosetta Stone for planet formation theories. They would give strong constraints on several aspects of planet formation, e.g. time-scales (planet formation would then be possible within 10 Myrs), the radius of the planet could indicate whether planets form by gravitational collapse (being larger when young) or accretion growth (being smaller when young). We present a survey, the main goal of which is to find and then characterise TEPs in very young open clusters.Comment: Poster contribution to Detection and Dynamics of Transiting Exoplanets (Haute Provence Observatory Colloquium, 23-27 August 2010

Transport Theoretical Description of Collisional Energy Loss in Infinite Quark-Gluon Matter

We study the time evolution of a high-momentum gluon or quark propagating through an infinite, thermalized, partonic medium utilizing a Boltzmann equation approach. We calculate the collisional energy loss of the parton, study its temperature and flavor dependence as well as the the momentum broadening incurred through multiple interactions. Our transport calculations agree well with analytic calculations of collisional energy-loss where available, but offer the unique opportunity to address the medium response as well in a consistent fashion.Comment: 12 pages, updated with additional references and typos correcte

Bucket Fuser: Statistical Signal Extraction for 1D 1H NMR Metabolomic Data

Untargeted metabolomics is a promising tool for identifying novel disease biomarkers and unraveling underlying pathomechanisms. Nuclear magnetic resonance (NMR) spectroscopy is particularly suited for large-scale untargeted metabolomics studies due to its high reproducibility and cost effectiveness. Here, one-dimensional (1D) 1H NMR experiments offer good sensitivity at reasonable measurement times. Their subsequent data analysis requires sophisticated data preprocessing steps, including the extraction of NMR features corresponding to specific metabolites. We developed a novel 1D NMR feature extraction procedure, called Bucket Fuser (BF), which is based on a regularized regression framework with fused group LASSO terms. The performance of the BF procedure was demonstrated using three independent NMR datasets and was benchmarked against existing state-of-the-art NMR feature extraction methods. BF dynamically constructs NMR metabolite features, the widths of which can be adjusted via a regularization parameter. BF consistently improved metabolite signal extraction, as demonstrated by our correlation analyses with absolutely quantified metabolites. It also yielded a higher proportion of statistically significant metabolite features in our differential metabolite analyses. The BF algorithm is computationally efficient and it can deal with small sample sizes. In summary, the Bucket Fuser algorithm, which is available as a supplementary python code, facilitates the fast and dynamic extraction of 1D NMR signals for the improved detection of metabolic biomarker

CMTr mediated 2`-O-ribose methylation status of cap adjacent-nucleotides across animals

ACKNOWLEDGMENTS We thank Mark Carrington and Nancy Standard for T. brucei total RNA, Jane Nimmo for honeybees, Caroline Chadwick for mouse tissue, Pawel Grzechnik for HEK293T cells, Roland Arnold for HCT116 cells, Rupert Fray for plasmids, and the National BioResource Project, Tokyo, Japan for the C. elegans CMTr2 strain. M.S. acknowledges funding from the Leverhulme Trust and the Biotechnology and Biological Sciences Research Council (BBSRC) (BB/R002932/1), J.P. and B.M. from BBSRC (BB/T002859/1), and F.M. from the Wellcome Trust (106955/Z/15/Z).Peer reviewedPublisher PD

Automorphisms of associative algebras and noncommutative geometry

A class of differential calculi is explored which is determined by a set of automorphisms of the underlying associative algebra. Several examples are presented. In particular, differential calculi on the quantum plane, the $h$-deformed plane and the quantum group GLpq(2) are recovered in this way. Geometric structures like metrics and compatible linear connections are introduced.Comment: 28 pages, some references added, several amendments of minor importance, remark on modular group in section 8 omitted, to appear in J. Phys.