Photon beam asymmetry $\Sigma$ measurements for $\omega$ photoproduction in the reaction $\vec{\gamma} p \to \omega p$ are reported for photon energies from 1.152 to 1.876 GeV. Data were taken using ...a linearly-polarized tagged photon beam, a cryogenic hydrogen target, and the CLAS spectrometer in Hall B at Jefferson Lab. The measurements we obtained markedly increase the size of the database for this observable, extend coverage to higher energies, and resolve discrepancies in previously published data. Comparisons of these new results with predictions from a chiral-quark-based model and from a dynamical coupled-channels model indicate the importance of interferences between $t$-channel meson exchange and $s$- and $u$-channel contributions, underscoring sensitivity to the nucleon resonances included in those descriptions. Comparisons with the Bonn-Gatchina partial-wave analysis indicate the $\Sigma$ data reported here help to fix the magnitudes of the interference terms between the leading amplitudes in that calculation (Pomeron exchange and the resonant portion of the $J^P=3/2^+$ partial wave), as well as the resonant portions of the smaller partial waves with $J^P$= $1/2^-$, $3/2^-$, and $5/2^+$.
Background: Surveillance of winter respiratory viral illness has been carried out for nearly 30 years using a clinical diagnosis by general practitioners as part of the Scottish Sentinel General ...Practice (SSGP) network. Contemparaneous laboratory diagnosis has not been available previously.
Objectives: To assess the proportion of influenza-like illness (ILI) attributable to influenza, respiratory syncytial virus (RSV) and picornavirus infection during the winter season. To compare the influenza PCR data with serology of paired blood samples.
Study design: Combined nose and throat swabs, from patients with ILI attending 15 general practices across Scotland, were submitted to the laboratory in virus PCR sample solution (VPSS). The extracted nucleic acid was tested using a multiplex reverse-transcription polymerase chain reaction (RT-PCR) assay. Serological analysis was performed on paired serum samples using complement fixation assays. The rate of influenza virus positivity was compared with reports of ILI obtained from the SSGP network.
Results: Of 240 samples received at the laboratory, 132 (55%) were PCR positive for influenza A virus. There were nine (3.8%) picornavirus and three (1.2%) RSV PCR positives, two (0.8%) were dual influenza A/picornavirus infections. Ninety four (39.2%) were negative for all viruses tested. Results on paired sera from 89 patients showed a rising titre to influenza A in 48 of the 57 PCR positive samples (84.2%). One PCR negative patient displayed a significant rising titre to influenza A. Virological data paralleled the SSGP data but was available at least a week earlier.
Conclusions: Influenza A infection was detected in the majority of patients with ILI; picornavirus infection was also shown to be an important cause of illness. PCR is a rapid and sensitive method for respiratory virus surveillance. Serology is slow, insensitive and difficult to interpret at low titres.
The beam-spin asymmetry, \(\Sigma\), for the reaction \(\gamma d\rightarrow pn\) has been measured using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator ...Facility (JLab) for six photon-energy bins between 1.1 and 2.3 GeV, and proton angles in the center-of-mass frame, \(\theta_{c.m.}\), between \(25^\circ\) and \(160^\circ\). These are the first measurements of beam-spin asymmetries at \(\theta_{c.m.}=90^\circ\) for photon-beam energies above 1.6 GeV, and the first measurements for angles other than \(\theta_{c.m.}=90^\circ\). The angular and energy dependence of \(\Sigma\) is expected to aid in the development of QCD-based models to understand the mechanisms of deuteron photodisintegration in the transition region between hadronic and partonic degrees of freedom, where both effective field theories and perturbative QCD cannot make reliable predictions.
The regulation of transendothelial fluid flow by glucocorticoids was studied in vitro with use of human endothelial cells cultured from Schlemm's canal (SCE) and the trabecular meshwork (TM) in ...conjunction with computer-linked flowmeters. After 2-7 wk of 500 nM dexamethasone (Dex) treatment, the following physiological, morphometric, and biochemical alterations were observed: a 3- to 5-fold increase in fluid flow resistance, a 2-fold increase in the representation of tight junctions, a 10- to 30-fold reduction in the mean area occupied by interendothelial "gaps" or preferential flow channels, and a 3- to 5-fold increase in the expression of the junction-associated protein ZO-1. The more resistive SCE cells expressed two isoforms of ZO-1; TM cells expressed only one. To investigate the role of ZO-1 in the aforementioned Dex effects, its expression was inhibited using antisense phosphorothioate oligonucleotides, and the response was compared with that observed with the use of sense and nonsense phosphorothioate oligonucleotides. Inhibition of ZO-1 expression abolished the Dex-induced increase in resistance and the accompanying alterations in cell junctions and gaps. These results support the hypothesis that intercellular junctions are necessary for the development and maintenance of transendothelial flow resistance in cultured SCE and TM cells and are likely involved in the mechanism of increased resistance associated with glucocorticoid exposure.
Phys.Rev.C75:045203,2007 We report measurements of the exclusive electroproduction of $K^+\Lambda$ and
$K^+\Sigma^0$ final states from a proton target using the CLAS detector at the
Thomas Jefferson ...National Accelerator Facility. The separated structure
functions $\sigma_T$, $\sigma_L$, $\sigma_{TT}$, and $\sigma_{LT}$ were
extracted from the $\Phi$- and $\epsilon$-dependent differential cross sections
taken with electron beam energies of 2.567, 4.056, and 4.247 GeV. This analysis
represents the first $\sigma_L/\sigma_T$ separation with the CLAS detector, and
the first measurement of the kaon electroproduction structure functions away
from parallel kinematics. The data span a broad range of momentum transfers
from $0.5\leq Q^2\leq 2.8$ GeV$^2$ and invariant energy from $1.6\leq W\leq
2.4$ GeV, while spanning nearly the full center-of-mass angular range of the
kaon. The separated structure functions reveal clear differences between the
production dynamics for the $\Lambda$ and $\Sigma^0$ hyperons. These results
provide an unprecedented data sample with which to constrain current and future
models for the associated production of strangeness, which will allow for a
better understanding of the underlying resonant and non-resonant contributions
to hyperon production.
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