28,721 research outputs found
Studies of low-energy ionic collisions Final report, 1 Oct. 1965 - 30 Sep. 1967
Ionic-molecular collisions, and collision induced dissociation of ion
A Dual Read-Out Assay to Evaluate the Potency of Compounds Active against Mycobacterium tuberculosis
PMCID: PMC3617142This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Solution of an infection model near threshold
We study the Susceptible-Infected-Recovered model of epidemics in the
vicinity of the threshold infectivity. We derive the distribution of total
outbreak size in the limit of large population size . This is accomplished
by mapping the problem to the first passage time of a random walker subject to
a drift that increases linearly with time. We recover the scaling results of
Ben-Naim and Krapivsky that the effective maximal size of the outbreak scales
as , with the average scaling as , with an explicit form for
the scaling function
Invasion threshold in heterogeneous metapopulation networks
We study the dynamics of epidemic and reaction-diffusion processes in
metapopulation models with heterogeneous connectivity pattern. In SIR-like
processes, along with the standard local epidemic threshold, the system
exhibits a global invasion threshold. We provide an explicit expression of the
threshold that sets a critical value of the diffusion/mobility rate below which
the epidemic is not able to spread to a macroscopic fraction of subpopulations.
The invasion threshold is found to be affected by the topological fluctuations
of the metapopulation network. The presented results provide a general
framework for the understanding of the effect of travel restrictions in
epidemic containment.Comment: 4 pages, 2 figure
High Energy Physics from High Performance Computing
We discuss Quantum Chromodynamics calculations using the lattice regulator.
The theory of the strong force is a cornerstone of the Standard Model of
particle physics. We present USQCD collaboration results obtained on Argonne
National Lab's Intrepid supercomputer that deepen our understanding of these
fundamental theories of Nature and provide critical support to frontier
particle physics experiments and phenomenology.Comment: Proceedings of invited plenary talk given at SciDAC 2009, San Diego,
June 14-18, 2009, on behalf of the USQCD collaboratio
Numerical analysis of droplet deposition in inkjet printed electronics assembly
In this paper, a computational approach for the analysis of microscale droplet impact dynamics is presented. The approach is intended to support a condition based monitoring system to enhance quality and reliability of inkjet printed electronics components. The Smoothed Particle Hydrodynamics (SPH) approach of Lucy and Gingold and Monaghan has been used as the basis for the model, with the δ-SPH terms of Marrone et al used to improve handling of the dynamic impact events and the gradient correction terms of Belytschko used to improve the accuracy of interface dynamics. Model validation has been performed through comparison against a macroscale dam break problem and through a microscale analysis designed to determine accurate surface tension-pressure behaviour based on the Young-Laplace relation. The model is used to assess impact of a single drop on a uniform surface and the three dimensional formation of multi-drop layers
Semileptonic Decay Scalar Form Factor and from Lattice QCD
We present a new study of D semileptonic decays on the lattice which employs
the Highly Improved Staggered Quark (HISQ) action for both the charm and the
light valence quarks. We work with MILC unquenched lattices and
determine the scalar form factor for
semileptonic decays. The form factor is obtained from a scalar current matrix
element that does not require any operator matching. We develop a new approach
to carrying out chiral/continuum extrapolations of . The method uses
the kinematic "" variable instead of or the kaon energy and is
applicable over the entire physical range. We find in the chiral plus
continuum limit and hereby improve the theory error on this quantity by a
factor of 4 compared to previous lattice determinations. Combining the
new theory result with recent experimental measurements of the product from BaBar and CLEO-c leads to the most
precise direct determination of the CKM matrix element to date,
, where the first error comes from experiment and the
second is the lattice QCD theory error. We calculate the ratio and find GeV and show
that this agrees with experiment.Comment: 23 pages, 31 figures, 11 tables. Added a paragraph in sction VII, and
updated with PDG 2010 instead of PDG 200
Recommended from our members
Modelling methodologies for quality assessment of 3D inkjet printed electronic products
Purpose of the Fraunhofer Direct Digital Manufacturing Conference is an intellectual exchange between researchers, enterprises and users of Additive Manufacturing technologies in order to gather the latest information about trends, progress, importance and the future potential of these technologies for industrial applications. The range of topics covers Product Development (incl. simulation, co-design, mass customization), Technologies (incl. bio-printing, hybrid processes, novel developments/visionary concepts, process chains for industrial production), Materials (incl. ceramics, bio-materials, multi-material approaches), Quality (incl. process/ part quality management) as well as further innovative and visionary approaches not fitting the range of topics above. Renowned international keynote speakers give insight into the latest trends and challenges in additive manufacturing in a variety of industry sectors, including biomedical, aerospace and automotive
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