24,986 research outputs found
Hybrid biomedical intelligent systems
"Copyright © 2012 Maysam Abbod et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited."The purpose of this special issue is to promote research and developments of the best work in the field of hybrid intelligent systems for biomedical applications
The right-to-manage default rule
We critically examine the right-to-manage as a legal default rule. We then assess the merits of alternative process and content defaults, as well as non-waivable terms and conditions. Finally, we suggest how various options might be combined in different circumstances
XUV Frequency Combs via Femtosecond Enhancement Cavities
We review the current state of tabletop extreme ultraviolet (XUV) sources
based on high harmonic generation (HHG) in femtosecond enhancement cavities
(fsEC). Recent developments have enabled generation of high photon flux (1014
photons/sec) in the XUV, at high repetition rates (>50 MHz) and spanning the
spectral region from 40 nm - 120 nm. This level of performance has enabled
precision spectroscopy with XUV frequency combs and promises further
applications in XUV spectroscopic and photoemission studies. We discuss the
theory of operation and experimental details of the fsEC and XUV generation
based on HHG, including current technical challenges to increasing the photon
flux and maximum photon energy produced by this type of system. Current and
future applications for these sources are also discussed.Comment: invited review article, 38 page
Unitarized Diffractive Scattering in QCD and Application to Virtual Photon Total Cross Sections
The problem of restoring Froissart bound to the BFKL-Pomeron is studied in an
extended leading-log approximation of QCD. We consider parton-parton scattering
amplitude and show that the sum of all Feynman-diagram contributions can be
written in an eikonal form. In this form dynamics is determined by the phase
shift, and subleading-logs of all orders needed to restore the Froissart bound
are automatically provided. The main technical difficulty is to find a way to
extract these subleading contributions without having to compute each Feynman
diagram beyond the leading order. We solve that problem by using nonabelian cut
diagrams introduced elsewhere. They can be considered as colour filters used to
isolate the multi-Reggeon contributions that supply these subleading-log terms.
Illustration of the formalism is given for amplitudes and phase shifts up to
three loops. For diffractive scattering, only phase shifts governed by one and
two Reggeon exchanges are needed. They can be computed from the
leading-log-Reggeon and the BFKL-Pomeron amplitudes. In applications, we argue
that the dependence of the energy-growth exponent on virtuality for
total cross section observed at HERA can be interpreted as the
first sign of a slowdown of energy growth towards satisfying the Froissart
bound. An attempt to understand these exponents with the present formalism is
discussed.Comment: 41 pages in revtex preprint format, with 10 figure
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