241 research outputs found
A Rosetta Stone Relating Conventions In Photo-Meson Partial Wave Analyses
A new generation of complete experiments in pseudoscalar meson
photo-production is being pursued at several laboratories. While new data are
emerging, there is some confusion regarding definitions of asymmetries and the
conventions used in partial wave analyses (PWA). We present expressions for
constructing asymmetries as coordinate-system independent ratios of cross
sections, along with the names used for these ratios by different PWA groups.
(This update reflects a recent change in the definition of an asymmetry as used
by one group.)Comment: v2: This update reflects a recent change in the definition of an
asymmetry as used by one PWA group -see Table 1. v1: 4 pages. Contribution to
the proceedings of the 8th International Workshop on the Physics of Excited
Nucleons (NSTAR2011), Newport News, VA, USA, May 17-20, 201
Excess length of hospital stay due to healthcare acquired infections. Methodologies evaluation
BACKGROUND:
Healthcare acquired infections (HAI) cause an increase of burden and in particular excess length of hospital stay (LOS) accounts for approximately up to 90% of total costs. Therefore accurate estimation of extra hospital stay due to healthcare acquired infections is very important.
METHODS:
The authors carried out a review comparing the principal methods internationally used for estimating the excess LOS attributable to healthcare acquired infections.
RESULTS:
The methods described and analysed are: 1) Implicit physician assessment; 2) appropriateness evaluation protocol; 3) unmatched case-control; 4) matched case-control; 5) regression analysis; 6) multistate model. The various methodologies are described underlining advantages and limits which researchers need to know before starting any economic analysis.
CONCLUSIONS:
Overall, studies taking into account the time-dependent nature of HAI show to give more precise and reliable results
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Laser Electron Gamma Source: Biennial progress report, June 1996
The LEGS facility provides intense, polarized, monochromatic {gamma}-ray beams by Compton backscattering laser light from relativistic electrons circulating in the X-Ray storage ring of the National Synchrotron Light Source at Brookhaven national Laboratory. Since 1990, experiments have concentrated on single polarization observables (polarized beams on unpolarized targets) in nuclear reactions involving the {Delta} resonance. Highlights of the last two years are given. An updated status of LEGS, and recent publications, is available on the WWW via http://WWW.LEGS.BNL.GOV/{approximately}LEGS/. In 1997 a new phase of operations will begin, focusing on double-polarization measurements with circularly polarized photon beams and longitudinally polarized nucleon targets. This work requires the development of (i) a new frozen-spin hydrogen-deuteride target that provides high polarizations for both nuclear species, and (ii) a new large acceptance detector array for measuring total reaction cross sections in both neutral and charged-particle channels. Progress on these instrumentation developments is an ongoing effort of the LEGS Spin Collaboration (LSC) and is discussed in the last section of this report
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Polarized photon facilities - windows to new physics
The status of new and proposed sources of intermediate-energy polarized photons is reviewed. The N {r_arrow} {delta} transition is discussed as an example of new physics that can be addressed at these facilities through precision measurements of polarization observables
Role of protein kinase C-delta in the regulation of collagen gene expression in scleroderma fibroblasts
Working with cultured dermal fibroblasts derived from control individuals and patients with systemic sclerosis (SSc), we have examined the effects of protein kinase C-delta (PKC-delta) on type I collagen biosynthesis and steady-state levels of COL1A1 and COL3A1 mRNAs. Rottlerin, a specific inhibitor of PKC-delta, exerted a powerful, dose-dependent inhibition of type I and type III collagen gene expression in normal and SSc cells. Optimal rottlerin concentrations caused a 70-90% inhibition of type I collagen production, a \u3e80% reduction in COL1A1 mRNA, and a \u3e70% reduction in COL3A1 mRNA in both cell types. In vitro nuclear transcription assays and transient transfections with COL1A1 promoter deletion constructs demonstrated that rottlerin profoundly reduced COL1A1 transcription and that this effect required a 129-bp promoter region encompassing nucleotides -804 to -675. This COL1A1 segment imparted rottlerin sensitivity to a heterologous promoter. Cotransfections of COL1A1 promoter constructs with a dominant-negative PKC-delta expression plasmid showed that suppression of this kinase silenced COL1A1 promoter activity. The results indicate that PKC-delta participates in the upregulation of collagen gene transcription in SSc and suggest that treatment with PKC-delta inhibitors could suppress fibrosis in this disease
On the Gerasimov-Drell-Hearn sum rule for the deuteron
The Gerasimov-Drell-Hearn sum rule is evaluated for the deuteron by explicit
integration up to 550 MeV including contributions from the photodisintegration
channel and from coherent and incoherent single pion production as well. The
photodisintegration channel converges fast enough in this energy range and
gives a large negative contribution, essentially from the resonant
state near threshold. Its absolute value is about the same size as the sum of
proton and neutron GDH values. It is only partially cancelled by the single
pion production contribution. But the incoherent channel has not reached
convergence at 550 MeV.Comment: 6 pages latex including 3 postscript figures, talk at the 15th Int.
Conf. on Few-Body Problems in Physics, Groningen, Netherlands, 22-26 July
1997. To be published in Nucl. Phys.
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