First Extraction of a Spin-Polarizability of the Proton

A proton spin-polarizability characterizing backward Compton scattering has been extracted from a dispersion analysis of data between 33 and 309 MeV. This backward spin-polarizability, "delta" = 27.1 +/-2.2(stat+sys) +2.8/-2.4(model) in units of 10^-4 fm^4, differs significantly from theoretical estimates which are dominated by pi0 t-channel exchange, and indicates a new contribution from the non-perturbative spin-structure of the proton. This new value for "delta" removes an apparent inconsistency in the difference of charge polarizabilities extracted from data above pi-threshold. Our global result, alpha-beta = 10.11 +/-1.74(stat+sys) +1.22/-0.86 (model) in units of 10^-4 fm^3, is consistent with the previous world average of data below 155 MeV. Our value for alpha+beta = 13.23 +/-0.86(stat+sys) +0.20/-0.49(model) is consistent with a recent re-evaluation of the Baldin sum rule.Comment: Small corrections to LEGS data incorporated; fits recalculated; Tables and Figures update

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

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

ILC Beam Energy Measurement by means of Laser Compton Backscattering

A novel, non-invasive method of measuring the beam energy at the International Linear Collider is proposed. Laser light collides head-on with beam particles and either the energy of the Compton scattered electrons near the kinematic end-point is measured or the positions of the Compton backscattered $\gamma$-rays, the edge electrons and the unscattered beam particles are recorded. A compact layout for the Compton spectrometer is suggested. It consists of a bending magnet and position sensitive detectors operating in a large radiation environment. Several options for high spatial resolution detectors are discussed. Simulation studies support the use of an infrared or green laser and quartz fiber detectors to monitor the backscattered photons and edge electrons. Employing a cavity monitor, the beam particle position downstream of the magnet can be recorded with submicrometer precision. Such a scheme provides a feasible and promising method to access the incident beam energy with precisions of $10^{-4}$ or better on a bunch-to-bunch basis while the electron and positron beams are in collision.Comment: 47 pages, 26 figures, version as accepted by Nucl. Instr. Meth. A after improvement

Spin observables for pion photoproduction on the deuteron in the Δ\Delta(1232)-resonance region

Spin observables for the three charge states of the pion for the pion photoproduction reaction on the deuteron, $\gamma d\to\pi NN$, with polarized photon beam and/or oriented deuteron target are predicted. For the beam-target double-spin asymmetries, it is found that only the longitudinal asymmetries $T_{20}^{\ell}$ and $T_{2\pm 2}^{\ell}$ do not vanish, whereas all the circular and the other longitudinal asymmetries do vanish. The sensitivity of spin observables to the model deuteron wave function is investigated. It has been found that only $T_{21}$ and $T_{22}$ are sensitive to the model deuteron wave function, in particular in the case of $\pi^0$-production above the $\Delta$-region, and that other asymmetries are not.Comment: 16 pages, 8 figures, accepted for publication in J. Phys. G: Nucl. Part. Phy

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 $^1S_0$ 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.

Measurements of polarized photo-pion production on longitudinally polarized HD and Implications for Convergence of the GDH Integral

We report new measurements of inclusive pion production from frozen-spin HD for polarized photon beams covering the Delta(1232) resonance. These provide data simultaneously on both H and D with nearly complete angular distributions of the spin-difference cross sections entering the Gerasimov-Drell-Hearn (GDH) sum rule. Recent results from Mainz and Bonn exceed the GDH prediction for the proton by 22 microbarns, suggesting as yet unmeasured high-energy components. Our pi0 data reveal a different angular dependence than assumed in Mainz analyses and integrate to a value that is 18 microbarns lower, suggesting a more rapid convergence. Our results for deuterium are somewhat lower than published data, considerably more precise and generally lower than available calculations.Comment: 4 pages, 4 figures. Submitted for publication in Physical Review Letter

Pseudoscalar meson photoproduction: from known to undiscovered resonances

The role of dynamics in spin observables for pseudoscalar meson photoproduction is investigated using a density matrix approach in a multipole truncated framework. Extraction of novel rules for $\gamma p \rightarrow \pi^+ n,~ K^+ \Lambda$ and $\eta p$ reactions based on resonance dominance, and on other broad and reasonable dynamical assumptions, are discussed. Observables that are particularly sensitive to missing nucleonic resonances predicted by quark-based approaches, are singled out.Comment: 22 pages, latex, 3 figure