920 research outputs found
Heavy quark impact factor in kT-factorization
We present the calculation of the finite part of the heavy quark impact factor at next-to-leading logarithmic accuracy in a form suitable for phenomenological studies such as the calculation of the cross-section for single bottom quark production at the LHC within the kT-factorization scheme.This work has been supported by the Research Executive Agency (REA) of the European Union under the Grant Agreement number PITN-GA-2010-264564 (LHCPhenoNet), by the Spanish Government and EU ERDF funds (grants FPA2007-60323, FPA2011-23778 and CSD2007-00042 Consolider Project CPAN) and by GV (PROMETEUII/2013/007). GC acknowledges support from Marie Curie Actions (PIEF-GA-2011-298582). MD acknowledges support from Juan de la Cierva programme (JCI-2011-11382).Peer reviewe
Apparatus and method for improvised explosive device (IED) network analysis
PatentTools and apparatus are presented for identification and
analysis of improvised explosive device (IED) networks,
including data acquisition tools and techniques providing
structured prompting and predefined answers for acquiring
structured IED data reports in a streamlined fashion using
uniform terminology with respect to IED components and/or
structure, as well as analysis methodologies employing IED
component level analysis with adjustable similarity correlation
and IED attribute filtering to expeditiously identify
likely IED networks using graphical renderings of IED
locations in a given geolocation range of interest and connection
indicators
Relaxation paths for single modes of vibrations in isolated molecules
A numerical simulation of vibrational excitation of molecules was devised,
and used to excite computational models of common molecules into a prescribed,
pure, normal vibration mode in the ground electronic state, with varying,
controlable energy content. The redistribution of this energy (either
non-chaotic or irreversible IVR) within the isolated, free molecule is then
followed in time with a view to determining the coupling strength between
modes. This work was triggered by the need to predict the general characters of
the infrared spectra to be expected from molecules in interstellar space, after
being excited by photon absorption or reaction with a radical. It is found that
IVR from a pure normal mode is very "restricted" indeed at energy contents of
one mode quantum or so. However, as this is increased, or when the excitation
is localized, our approach allows us to isolate, describe and quantify a number
of interesting phenomena, known to chemists and in non-linear mechanics, but
difficult to demonstrate experimentally: frequency dragging, mode locking or
quenching or, still, instability near a potential surface crossing, the first
step to generalized chaos as the energy content per mode is increased.Comment: 25 pages, 15 figures; accepted by J. Atom. Phys.
The CCFM Monte Carlo generator CASCADE 2.2.0
CASCADE is a full hadron level Monte Carlo event generator for ep, \gamma p
and p\bar{p} and pp processes, which uses the CCFM evolution equation for the
initial state cascade in a backward evolution approach supplemented with off -
shell matrix elements for the hard scattering. A detailed program description
is given, with emphasis on parameters the user wants to change and variables
which completely specify the generated events
Multi-gluon helicity amplitudes with one off-shell leg within high energy factorization
Basing on the Slavnov-Taylor identities, we derive a new prescription to
obtain gauge invariant tree-level scattering amplitudes for the process g*g->Ng
within high energy factorization. Using the helicity method, we check the
formalism up to several final state gluons, and we present analytical formulas
for the the helicity amplitudes for N=2. We also compare the method with
Lipatov's effective action approach.Comment: 25 pages, quite a few figures, an appendix added, typos correcte
Evaluation of optical coherence tomography findings in age-related macular degeneration: a reproducibility study of two independent reading centres
International audienceBackground/aims : To determine the reproducibility among readers of two independent certified centers, the Vienna Reading Center (VRC) and the University of Wisconsin-Madison Reading Center (UW-FPRC) for OCT images in age-related macular degeneration (AMD). Methods : Fast macular thickness scans and 6 mm cross hair scans were obtained from 100 eyes with all subtypes of AMD using Stratus OCT. Consensus readings were performed by two certified OCT readers of each Reading Center using their grading protocol. Common variables of both grading protocols, such as presence of cystoid spaces, subretinal fluid, vitreomacular traction and retinal pigment epithelial detachment were compared using kappa statistics. In addition, the intraclass correlation coefficient (ICC) was calculated for center point thickness (CPT) of values remeasured manually in the presence of alignment errors. Results : The reproducibility was dependent on the variable measured with a kappa value of 0.81 for the presence of cystoid spaces, 0.78 for the presence of subretinal fluid and 0.795 for the presence of vitreomacular traction. The lowest reproducibility was found for the presence of retinal pigment epithelial detachment with a kappa value of 0.51. The CPT was remeasured in 29 out of 100 scans at both sites with an ICC of the remeasured thicknesses of 0.92. Conclusion : OCT scan data are crucial in monitoring treatment efficacy in AMD clinical trials. For comparison of results obtained by different Reading Centers, the inter-Reading Center reproducibility is essential. Although the reproducibility is generally high, the reliability depends on the selected morphological parameters
A Three Dimensional Analysis of Au-Silica Core-Shell Nanoparticles Using Medium Energy Ion Scattering
The medium energy ion scattering (MEIS) facility at the IIAA Huddersfield has been used
for the analysis of a monolayer of Au-silica core-shell nanoparticles deposited on Si substrate.
Both spherical and rod shape particles were investigated and the spectra produced by 100 keV He+
ions scattered through angles of 90º and 125º were compared with the results of RBS-MAST [1]
simulations performed on artificial 3D model cells containing the nanoparticles. The thickness of
the silica shell, the diameter of the Au spheres, and the diameter and length of the Au nano-rods
were determined from best fits of the measured set of MEIS spectra.
In addition, the effect of ion irradiation on the silica shell and gold core was monitored by
MEIS measurements in conjunction with RBS-MAST simulations. Ion bombardment was
performed under largely different conditions, i.e., by 30 keV Ar+, 150 keV Fe+, or 2.8 MeV N+
ions in the dose range of 2×1015 - 2×1016 cm-2. Significant changes in the particle geometry can be
observed due to ion beam-induced sputtering and recoil effects, the significance of which was
estimated from full-cascade SRIM simulations.
Rutherford backscattering spectrometry (RBS), Field emission scanning electron microscopy
(FESEM), and Atomic Force Microscopy (AFM) techniques have been applied as complementary
characterization tools to monitor the amount of gold and surface morphology on the un-irradiated
and irradiated sample areas. We show that MEIS can yield spatial information on the geometrical
changes of particulate systems at the nanometre scale
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