8,648 research outputs found
Numerical Simulation of Pollutant Transport in a Shallow-Water System on the Cell Heterogeneous Processor
[Abstract] This paper presents an implementation, optimized for the Cell processor, of a finite volume numerical scheme for 2D shallow-water systems with pollutant transport. A description of the special architecture and programming required by the Cell processor motivates the methodology to develop optimized implementations for this platform. This process involves parallelization, data structure reorganization, explicit transfers of data and computation vectorization. Our implementation, tested using a realistic problem, achieves very good speedups with respect to the sequential execution on a standard CPU.This work was partially supported by the Science and Innovation Ministry of Spain (Projects TIN2010-16735, MTM2010-21135-C02-01 and MTM2009-11923), Xunta de Galicia CN2012/211 (partially supported by FEDER funds), and the FPU program of the Spanish Government (ref AP2009-4752)Xunta de Galicia; CN 2012/21
NextMed, Augmented and Virtual Reality platform for 3D medical imaging visualization
The visualization of the radiological results with more advanced
techniques than the current ones, such as Augmented Reality
and Virtual Reality technologies, represent a great advance for
medical professionals, by eliminating their imagination capacity
as an indispensable requirement for the understanding of
medical images. The problem is that for its application it is
necessary to segment the anatomical areas of interest, and this
currently involves the intervention of the human being. The
Nextmed project is presented as a complete solution that
includes DICOM images import, automatic segmentation of
certain anatomical structures, 3D mesh generation of the
segmented area, visualization engine with Augmented Reality
and Virtual Reality, all thanks to different software platforms
that have been implemented and detailed, including results
obtained from real patients. We will focus on the visualization
platform using both Augmented and Virtual Reality technologies
to allow medical professionals to work with 3d model
representation of medical images in a different way taking
advantage of new technologies
Many-body GW calculations of ground-state properties: Quasi-2D electron systems and van der Waals forces
We present GW many-body results for ground-state properties of two simple but very distinct families of inhomogeneous systems in which traditional implementations of density-functional theory (DFT) fail drastically. The GW approach gives notably better results than the well-known random-phase approximation, at a similar computational cost. These results establish GW as a superior alternative to standard DFT schemes without the expensive numerical effort required by quantum Monte Carlo simulations
Electrical characterization of atomic-layer-deposited hafnium oxide films from hafnium tetrakis(dimethylamide) and water/ozone: Effects of growth temperature, oxygen source, and postdeposition annealing
The electrical properties of HfO2-based metal-insulator- semiconductor capacitors have been systematically investigated by means of I-V and C-V characteristics, admittance spectroscopy, deep level transient spectroscopy, conductance transient, and flat band voltage transient techniques. Attention is also given to the study of the temperature dependence of the leakage current. HfO2 films were grown on p-type silicon substrates by atomic layer deposition using hafnium tetrakis(dimethylamide) as hafnium precursor, and ozone or water as oxygen precursors. The growth temperature ranged from 150 to 350 °C. Low growth temperatures prevent decomposition and high growth rate, as well as high contamination levels. As a result, the leakage current is lower for lower deposition temperatures. Some of the deposited samples were submitted to a postdeposition annealing at 650 °C in N2 atmosphere, showing a decrease in the leakage current and an increase in the equivalent oxide thickness (EOT), whereas interfacial state density increases and defect density inside the dielectric bulk decreases. Regarding dielectric reliability, in our experimental conditions, HfO 2 layers grown at 150 °C exhibit the largest EOT and breakdown voltage. The electrical behaviour is clearly linked with structural properties, and especially with the formation of an interfacial layer between the HfO 2 layer and the silicon substrate, as well as with the presence of several impurities. © 2013 American Vacuum Society.Peer Reviewe
Mounier-Kuhn syndrome: a rare and often overlooked cause of bronchial dilation and recurrent respiratory tract infections
Developing a Business Application with BPM and MDE
In this paper we have designed an architecture for
the generation of a business application, that allows to business
users to adapt their processes to the constant change. At the
moment all the architectures based to a great extent on SOA
allow to modify the processes in a short period of time, but we
go beyond and give the possibility to the business user of
modifying their processes. To design this architecture, we rely
on the fundamental use of two technologies: BPM (Business
Process Modeling) and MDE (Model Driven Engineering).
Inside these technologies we focus on the creation of a business
process notation extended from BPMN that is agile, easy to
learn and design, and capable to provide semantic information
about the process. Therefore this notation allows business
process to modify their processes to achieve the proposed goal
Finite axisymmetric charged dust disks in conformastatic spacetimes
An infinite family of axisymmetric charged dust disks of finite extension is
presented. The disks are obtained by solving the vacuum Einstein-Maxwell
equations for conformastatic spacetimes, which are characterized by only one
metric function. In order to obtain the solutions, it is assumed that the
metric function and the electric potential are functionally related and that
the metric function is functionally dependent of another auxiliary function,
which is taken as a solution of Laplace equation. The solutions for the
auxiliary function are then taken as given by the infinite family of
generalized Kalnajs disks recently obtained by Gonz\'alez and Reina (MNRAS 371,
1873, 2006), which is expressed in terms of the oblate spheroidal coordinates
and represents a well behaved family of finite axisymmetric flat galaxy models.
The so obtained relativistic thin disks have then a charge density that is
equal, except maybe by a sign, to their mass density, in such a way that the
electric and gravitational forces are in exact balance. The energy density of
the disks is everywhere positive and well behaved, vanishing at the edge.
Accordingly, as the disks are made of dust, their energy-momentum tensor it
agrees with all the energy conditions.Comment: Submitted to PR
Symmetry Breaking and False Vacuum Decay after Hybrid Inflation
We discuss the onset of symmetry breaking from the false vacuum in generic
scenarios in which the mass squared of the symmetry breaking (Higgs) field
depends linearly with time, as it occurs, via the evolution of the inflaton, in
models of hybrid inflation. We show that the Higgs fluctuations evolve from
quantum to classical during the initial stages. This justifies the subsequent
use of real-time lattice simulations to describe the fully non-perturbative and
non-linear process of symmetry breaking. The early distribution of the Higgs
field is that of a smooth classical gaussian random field, and consists of
lumps whose shape and distribution is well understood analytically. The lumps
grow with time and develop into ``bubbles'' which eventually collide among
themselves, thus populating the high momentum modes, in their way towards
thermalization at the true vacuum. With the help of some approximations we are
able to provide a quasi-analytic understanding of this process.Comment: 33 pages, 16 figures, LaTeX, uses revtex. Version to be published in
Phys. Rev. with minor change
Structural study of the type II 3-dehydroquinate dehydratase from Actinobacillus pleuropneumoniae
9 pages, 7 figures, 2 tables.The structure of the type II dehydroquinate dehydratase (DHQase) from Actinobacillus pleuropneumoniae, the third enzyme of the shikimate pathway, has been determined. Crystals diffracting to 1.7 Å were obtained in space and on earth using the counter-diffusion technique. The structure was solved using molecular replacement and refined to high resolution. The overall structure of the dodecameric enzyme is described and compared with structures of DHQases from other bacteria. DHQases contain a flexible loop that presumably closes over the active site upon substrate binding. The enzyme can exist in an open or closed conformation. The present structure displays the open conformation, with a sulfate anion bound in the active site. The availability of this structure opens a route to structure-based antibiotics targetting this pathogenic bacterium.We thank Professor Kabsch for providing XDS free of charge. We acknowledge the support of the European Space Agency and the European Community Action to Research Infrastructure
Action of the Improving Human Potential Programme to the EMBL Hamburg Outstation, contract No. HPRI-CT-1999-00017. We thank Olivier Minster (ESA) for his support of
space science. The authors acknowledge the excellent work of Dr Eva ManÄ as in managing the logistics concerning the space mission. We thank Viscount Dirk Frimout for his support for space crystallization experiments.Peer reviewe
Environmental profile analysis of MDF panels production: study in a brazilian technological condition
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