434 research outputs found
Level-crossing spectroscopy of the 7, 9, and 10D_5/2 states of 133Cs and validation of relativistic many-body calculations of the polarizabilities and hyperfine constants
We present an experimental and theoretical investigation of the
polarizabilities and hyperfine constants of D_J states in 133Cs for J=3/2 and
J=5/2. New experimental values for the hyperfine constant A are obtained from
level-crossing signals of the (7,9,10)D_5/2 states of 133Cs and precise
calculations of the tensor polarizabilities alpha_2. The results of
relativistic many-body calculations for scalar and tensor polarizabilities of
the (5-10)D_3/2 and (5-10)D_5/2 states are presented and compared with measured
values from the literature. Calculated values of the hyperfine constants A for
these states are also presented and checked for consistency with experimental
values.Comment: 12 pages, revtex4, 11 figure file
Pion-nucleon scattering in a meson-exchange model
The pi-N interaction is studied within a meson-exchange model and in a
coupled-channels approach which includes the channels pi-N, eta-N, as well as
three effective pi-pi-N channels namely rho-N, pi-Delta, and sigma-N. Starting
out from an earlier model of the Julich group systematic improvements in the
dynamics and in some technical aspects are introduced. With the new model an
excellent quantitative reproduction of the pi-N phase shifts and inelasticity
parameters in the energy region up to 1.9 GeV and for total angular momenta J
leq 3/2 is achieved. Simultaneously, good agreement with data for the total and
differential pi-N -> eta-N transition cross sections is obtained. The
connection of the pi_N dynamics in the S_{11} partial wave with the reaction
pi-N -> eta-N is discussed.Comment: 32 pages, 9 figure
A unitary model for meson-nucleon scattering
In an effective Lagrangian model employing the K-matrix approximation we
extract nucleon resonance parameters. To this end we analyze simultaneously all
available data for reactions involving the final states , ,
and in the energy range GeV. The background contributions are generated consistently from the
relevant Feynman amplitudes, thus significantly reducing the number of free
parameters.Comment: Revised version. 60 pages, 17 figures. Two figures and a short
discussion (\pi N \to \eta N, K \Lambda amplitudes) added, typos and minor
errors in the citations correcte
Validation of a 5-item Tool to Measure Patient Assessment of Clinician Compassion in the Emergency Department.
BACKGROUND: To test if the 5-item compassion measure (a tool previously validated in the outpatient setting to measure patient assessment of clinician compassion) is a valid and reliable tool to quantify a distinct construct (i.e. clinical compassion) among patients evaluated in the emergency department (ED).
METHODS: Cross-sectional study conducted in three academic emergency departments in the U.S. between November 2018 and April 2019. We enrolled adult patients who were evaluated in the EDs of the participating institutions and administered the 5-item compassion measure after completion of care in the ED. Validity testing was performed using confirmatory factor analysis. Cronbach\u27s alpha was used to test reliability. Convergent validity with patient assessment of overall satisfaction questions was tested using Spearman correlation coefficients and we tested if the 5-item compassion measure assessed a construct distinct from overall patient satisfaction using confirmatory factor analysis.
RESULTS: We analyzed 866 patient responses. Confirmatory factor analysis found all five items loaded well on a single construct and our model was found to have good fit. Reliability was excellent (Cronbach\u27s alpha = 0.93) among the entire cohort. These results remained consistent on sub-analyses stratified by individual institutions. The 5-item compassion measure had moderate correlation with overall patient satisfaction (r = 0.66) and patient recommendation of the ED to friends and family (r = 0.57), but reflected a patient experience domain (i.e. compassionate care) distinctly different from patient satisfaction.
CONCLUSIONS: The 5-item compassion measure is a valid and reliable tool to measure patient assessment of clinical compassion in the ED
eta N S-wave scattering length in a three coupled channel, multiresonance, unitary model
The S-wave scattering length for eta-N elastic scattering is extracted from
the S-wave T-matrix in a three coupled channel, multiresonance unitary model.
Results are compared with values already reported in literature which are
obtained applying multichannel, but single resonance -- no background models. A
dispersion among the previously published values of the real part of the S-wave
scattering length is observed. We demonstrate that the reported spread
originates from the strong sensitivity of the scattering length upon the small
variation of the used input resonance parameters. In addition, we show that
eta-N scattering length value obtained in single resonance -- no background
models significantly increases if background term is added in a unitary way. We
question the reliability of previously reported values based only on the single
resonance -- no background models, and demonstrate that the value of the eta-N
S-wave scattering length obtained in this publication is much more realistic
because of the multiresonance and unitary approach.Comment: revtex, 20 pages + 3 figures (PostScript: gzip + uuencode) included,
submitted to Phys. Rev. C, brief Reports
Measurement of the B0-anti-B0-Oscillation Frequency with Inclusive Dilepton Events
The - oscillation frequency has been measured with a sample of
23 million \B\bar B pairs collected with the BABAR detector at the PEP-II
asymmetric B Factory at SLAC. In this sample, we select events in which both B
mesons decay semileptonically and use the charge of the leptons to identify the
flavor of each B meson. A simultaneous fit to the decay time difference
distributions for opposite- and same-sign dilepton events gives ps.Comment: 7 pages, 1 figure, submitted to Physical Review Letter
Measurement of D-s(+) and D-s(*+) production in B meson decays and from continuum e(+)e(-) annihilation at √s=10.6 GeV
This is the pre-print version of the Article. The official published version can be accessed from the links below. Copyright @ 2002 APSNew measurements of Ds+ and Ds*+ meson production rates from B decays and from qq̅ continuum events near the Υ(4S) resonance are presented. Using 20.8 fb-1 of data on the Υ(4S) resonance and 2.6 fb-1 off-resonance, we find the inclusive branching fractions B(B⃗Ds+X)=(10.93±0.19±0.58±2.73)% and B(B⃗Ds*+X)=(7.9±0.8±0.7±2.0)%, where the first error is statistical, the second is systematic, and the third is due to the Ds+→φπ+ branching fraction uncertainty. The production cross sections σ(e+e-→Ds+X)×B(Ds+→φπ+)=7.55±0.20±0.34pb and σ(e+e-→Ds*±X)×B(Ds+→φπ+)=5.8±0.7±0.5pb are measured at center-of-mass energies about 40 MeV below the Υ(4S) mass. The branching fractions ΣB(B⃗Ds(*)+D(*))=(5.07±0.14±0.30±1.27)% and ΣB(B⃗Ds*+D(*))=(4.1±0.2±0.4±1.0)% are determined from the Ds(*)+ momentum spectra. The mass difference m(Ds+)-m(D+)=98.4±0.1±0.3MeV/c2 is also measured.This work was supported by DOE and NSF (USA), NSERC (Canada), IHEP (China), CEA and CNRS-IN2P3 (France), BMBF (Germany), INFN (Italy), NFR (Norway), MIST (Russia), and PPARC (United Kingdom). Individuals have received support from the Swiss NSF, A. P. Sloan Foundation, Research Corporation, and Alexander von Humboldt Foundation
A Study of B0 -> J/psi K(*)0 pi+ pi- Decays with the Collider Detector at Fermilab
We report a study of the decays B0 -> J/psi K(*)0 pi+ pi-, which involve the
creation of a u u-bar or d d-bar quark pair in addition to a b-bar -> c-bar(c
s-bar) decay. The data sample consists of 110 1/pb of p p-bar collisions at
sqrt{s} = 1.8 TeV collected by the CDF detector at the Fermilab Tevatron
collider during 1992-1995. We measure the branching ratios to be BR(B0 -> J/psi
K*0 pi+ pi-) = (8.0 +- 2.2 +- 1.5) * 10^{-4} and BR(B0 -> J/psi K0 pi+ pi-) =
(1.1 +- 0.4 +- 0.2) * 10^{-3}. Contributions to these decays are seen from
psi(2S) K(*)0, J/psi K0 rho0, J/psi K*+ pi-, and J/psi K1(1270)
Defining the interval for monitoring potential adverse events following immunization (AEFIs) after receipt of live viral vectored vaccines
Live viral vectors that express heterologous antigens of the target pathogen are being investigated in the development of novel vaccines against serious infectious agents like HIV and Ebola. As some live recombinant vectored vaccines may be replication-competent, a key challenge is defining the length of time for monitoring potential adverse events following immunization (AEFI) in clinical trials and epidemiologic studies. This time period must be chosen with care and based on considerations of pre-clinical and clinical trials data, biological plausibility and practical feasibility. The available options include: (1) adapting from the current relevant regulatory guidelines; (2) convening a panel of experts to review the evidence from a systematic literature search to narrow down a list of likely potential or known AEFI and establish the optimal risk window(s); and (3) conducting “near real-time“ prospective monitoring for unknown clustering's of AEFI in validated large linked vaccine safety databases using Rapid Cycle Analysis for pre-specified adverse events of special interest (AESI) and Treescan to identify previously unsuspected outcomes. The risk window established by any of these options could be used along with (4) establishing a registry of clinically validated pre-specified AESI to include in case-control studies. Depending on the infrastructure, human resources and databases available in different countries, the appropriate option or combination of options can be determined by regulatory agencies and investigators
Defining the interval for monitoring potential adverse events following immunization (AEFIs) after receipt of live viral vectored vaccines
Live viral vectors that express heterologous antigens of the target pathogen are being investigated in the development of novel vaccines against serious infectious agents like HIV and Ebola. As some live recombinant vectored vaccines may be replication-competent, a key challenge is defining the length of time for monitoring potential adverse events following immunization (AEFI) in clinical trials and epidemiologic studies. This time period must be chosen with care and based on considerations of pre-clinical and clinical trials data, biological plausibility and practical feasibility. The available options include: (1) adapting from the current relevant regulatory guidelines; (2) convening a panel of experts to review the evidence from a systematic literature search to narrow down a list of likely potential or known AEFI and establish the optimal risk window(s); and (3) conducting “near real-time“ prospective monitoring for unknown clustering's of AEFI in validated large linked vaccine safety databases using Rapid Cycle Analysis for pre-specified adverse events of special interest (AESI) and Treescan to identify previously unsuspected outcomes. The risk window established by any of these options could be used along with (4) establishing a registry of clinically validated pre-specified AESI to include in case-control studies. Depending on the infrastructure, human resources and databases available in different countries, the appropriate option or combination of options can be determined by regulatory agencies and investigators
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