55,710 research outputs found
OGSA/Globus Evaluation for Data Intensive Applications
We present an architecture of Globus Toolkit 3 based testbed intended for
evaluation of applicability of the Open Grid Service Architecture (OGSA) for
Data Intensive Applications.Comment: To be published in the proceedings of the XIX International Symposium
on Nuclear Electronics and Computing (NEC'2003), Bulgaria, Varna, 15-20
September, 200
A Game-Theoretic Foundation for the Maximum Software Resilience against Dense Errors
Safety-critical systems need to maintain their functionality in the presence of multiple errors caused by component failures or disastrous environment events. We propose a game-theoretic foundation for synthesizing control strategies that maximize the resilience of a software system in defense against a realistic error model. The new control objective of such a game is called -resilience. In order to be -resilient, a system needs to rapidly recover from infinitely many waves of a small number of up to close errors provided that the blocks of up to errors are separated by short time intervals, which can be used by the system to recover. We first argue why we believe this to be the right level of abstraction for safety critical systems when local faults are few and far between. We then show how the analysis of -resilience problems can be formulated as a model-checking problem of a mild extension to the alternating-time -calculus (AMC). The witness for resilience, which can be provided by the model checker, can be used for providing control strategies that are optimal with respect to resilience. We show that the computational complexity of constructing such optimal control strategies is low and demonstrate the feasibility of our approach through an implementation and experimental results
Horava-Lifshitz gravity: a status report
This is intended to be a brief introduction and overview of Horava-Lifshitz
gravity. The motivation and all of the various version of the theory (to date)
are presented. The dynamics of the theory are discussed in some detail, with a
focus on low energy viability and consistency, as these have been the issues
that attracted most of the attention in the literature so far. Other properties
of the theory and developments within its framework are also covered, such as:
its relation to Einstein-aether theory, cosmology, and future perspectives.Comment: 17 pages, no figures, based on talk given at the 14th Conference on
Recent Developments in Gravity (NEBXIV), Ioannina, Greece, 8-11 Jun 2010; v2:
minor changes to match published version, references adde
Gain Modulation by an Urgency Signal Controls the Speed–Accuracy Trade-Off in a Network Model of a Cortical Decision Circuit
The speed–accuracy trade-off (SAT) is ubiquitous in decision tasks. While the neural mechanisms underlying decisions are generally well characterized, the application of decision-theoretic methods to the SAT has been difficult to reconcile with experimental data suggesting that decision thresholds are inflexible. Using a network model of a cortical decision circuit, we demonstrate the SAT in a manner consistent with neural and behavioral data and with mathematical models that optimize speed and accuracy with respect to one another. In simulations of a reaction time task, we modulate the gain of the network with a signal encoding the urgency to respond. As the urgency signal builds up, the network progresses through a series of processing stages supporting noise filtering, integration of evidence, amplification of integrated evidence, and choice selection. Analysis of the network's dynamics formally characterizes this progression. Slower buildup of urgency increases accuracy by slowing down the progression. Faster buildup has the opposite effect. Because the network always progresses through the same stages, decision-selective firing rates are stereotyped at decision time
Gravitational Slingshot of Young Massive Stars in Orion
The Orion Nebula Cluster (ONC) is the nearest region of massive star
formation and thus a crucial testing ground for theoretical models. Of
particular interest amongst the ONC's ~1000 members are: \theta^1 Ori C, the
most massive binary in the cluster with stars of masses 38 and 9 MSun (Kraus et
al. 2009); the Becklin-Neugebauer (BN) object, a 30 km/s runaway star of ~8
MSun (Tan 2004); and the Kleinmann-Low (KL) nebula protostar, a
highly-obscured, ~15 MSun object still accreting gas while also driving a
powerful, apparently "explosive" outflow (Allen & Burton 1993). The unusual
behavior of BN and KL is much debated: How did BN acquire its high velocity?
How is this related to massive star formation in the KL nebula? Here we report
the results of a systematic survey using ~ 10^7 numerical experiments of
gravitational interactions of the \theta^1C and BN stars. We show that
dynamical ejection of BN from this triple system at its observed velocity
leaves behind a binary with total energy and eccentricity matching those
observed for \theta^1C. Five other observed properties of \theta^C are also
consistent with it having ejected BN and altogether we estimate there is only a
<~ 10^{-5} probability that \theta^1C has these properties by chance. We
conclude that BN was dynamically ejected from the \theta^1C system about 4,500
years ago. BN has then plowed through the KL massive-star-forming core within
the last 1,000 years causing its recently-enhanced accretion and outflow
activity.Comment: 16 pages, 9 figures, 1 table, accepted to Ap
Hepatocyte Growth Factor Receptor c-Met Instructs T Cell Cardiotropism and Promotes T Cell Migration to the Heart via Autocrine Chemokine Release
© 2015 The Authors. Published by Elsevier Inc.
This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)This study was funded by the British Heart Foundation (RG/09/002/2642 to F.M.M.-B.) and the Medical Research Council of the UK (G0901084 to F.M.M.-B.). ImageStream X was funded by the Wellcome Trust (101604/Z/13/Z). This work forms part of the research themes contributing to the translational research portfolio of Barts and the London Cardiovascular Biomedical Research Unit, which is supported and funded by the National Institute of Health Research
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Initial Development toward Non-Invasive Drug Monitoring via Untargeted Mass Spectrometric Analysis of Human Skin.
Drug monitoring is crucial for providing accurate and effective care; however, current methods (e.g., blood draws) are inconvenient and unpleasant. We aim to develop a non-invasive method for the detection and monitoring of drugs via human skin. The initial development toward this aim required information about which drugs, taken orally, can be detected via the skin. Untargeted liquid chromatography-mass spectrometry (LC-MS) was used as it was unclear if drugs, known drug metabolites, or other transformation products were detectable. In accomplishing our aim, we analyzed samples obtained by swabbing the skin of 15 kidney transplant recipients in five locations (forehead, nasolabial area, axillary, backhand, and palm), bilaterally, on two different clinical visits. Untargeted LC-MS data were processed using molecular networking via the Global Natural Products Social Molecular Networking platform. Herein, we report the qualitative detection and location of drugs and drug metabolites. For example, escitalopram/citalopram and diphenhydramine, taken orally, were detected in forehead, nasolabial, and hand samples, whereas N-acetyl-sulfamethoxazole, a drug metabolite, was detected in axillary samples. In addition, chemicals associated with environmental exposure were also detected from the skin, which provides insight into the multifaceted chemical influences on our health. The proof-of-concept results presented support the finding that the LC-MS and data analysis methodology is currently capable of the qualitative assessment of the presence of drugs directly via human skin
Darboux transformation for the modified Veselov-Novikov equation
A Darboux transformation is constructed for the modified Veselov-Novikov
equation.Comment: Latex file,8 pages, 0 figure
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