Evidence for the Onset of Color Transparency in ρ0\rho^0 Electroproduction off Nuclei

We have measured the nuclear transparency of the incoherent diffractive $A(e,e'\rho^0)$ process in $^{12}$C and $^{56}$Fe targets relative to $^2$H using a 5 GeV electron beam. The nuclear transparency, the ratio of the produced $\rho^0$'s on a nucleus relative to deuterium, which is sensitive to $\rho A$ interaction, was studied as function of the coherence length ($l_c$), a lifetime of the hadronic fluctuation of the virtual photon, and the four-momentum transfer squared ($Q^2$). While the transparency for both $^{12}$C and $^{56}$Fe showed no $l_c$ dependence, a significant $Q^2$ dependence was measured, which is consistent with calculations that included the color transparency effects.Comment: 6 pages and 4 figure

All-sky search for gravitational-wave bursts in the second joint LIGO-Virgo run

We present results from a search for gravitational-wave bursts in the data collected by the LIGO and Virgo detectors between July 7, 2009 and October 20, 2010: data are analyzed when at least two of the three LIGO-Virgo detectors are in coincident operation, with a total observation time of 207 days. The analysis searches for transients of duration ≲1  s over the frequency band 64–5000 Hz, without other assumptions on the signal waveform, polarization, direction or occurrence time. All identified events are consistent with the expected accidental background. We set frequentist upper limits on the rate of gravitational-wave bursts by combining this search with the previous LIGO-Virgo search on the data collected between November 2005 and October 2007. The upper limit on the rate of strong gravitational-wave bursts at the Earth is 1.3 events per year at 90% confidence. We also present upper limits on source rate density per year and Mpc^3 for sample populations of standard-candle sources. As in the previous joint run, typical sensitivities of the search in terms of the root-sum-squared strain amplitude for these waveforms lie in the range ∼5×10^(-22)  Hz^(-1/2) to ∼1×10^(-20)  Hz^(-1/2). The combination of the two joint runs entails the most sensitive all-sky search for generic gravitational-wave bursts and synthesizes the results achieved by the initial generation of interferometric detectors

Issues in Multiagent Resource Allocation

The allocation of resources within a system of autonomous agents, that not only havepreferences over alternative allocations of resources but also actively participate in com-puting an allocation, is an exciting area of research at the interface of Computer Scienceand Economics. This paper is a survey of some of the most salient issues in MultiagentResource Allocation. In particular, we review various languages to represent the pref-erences of agents over alternative allocations of resources as well as different measuresof social welfare to assess the overall quality of an allocation. We also discuss pertinentissues regarding allocation procedures and present important complexity results. Ourpresentation of theoretical issues is complemented by a discussion of software packagesfor the simulation of agent-based market places. We also introduce four major applica-tion areas for Multiagent Resource Allocation, namely industrial procurement, sharingof satellite resources, manufacturing control, and grid computingouinonouirechercheInternationa