4,412 research outputs found
Stability of the Zagreb Carnegie-Mellon-Berkeley model
In ref. [1] we have used the Zagreb realization of Carnegie-Melon-Berkeley
coupled-channel, unitary model as a tool for extracting pole positions from the
world collection of partial wave data, with the aim of eliminating model
dependence in pole-search procedures. In order that the method is sensible, we
in this paper discuss the stability of the method with respect to the strong
variation of different model ingredients. We show that the Zagreb CMB procedure
is very stable with strong variation of the model assumptions, and that it can
reliably predict the pole positions of the fitted partial wave amplitudes.Comment: 25 pages, 12 figures, 19 table
Multipole analysis of spin observables in vector meson photoproduction
A multipole analysis of vector meson photoproduction is formulated as a
generalization of the pseudoscalar meson case. Expansion of spin observables in
the multipole basis and behavior of these observables near threshold and
resonances are examined.Comment: 15 pages, latex, 2 figure
Hyperon-Nucleon Final State Interaction in Kaon Photoproduction of the Deuteron
Final state hyperon-nucleon interaction in strangeness photoproduction of the
deuteron is investigated making use of the covariant reaction formalism and the
P-matrix approach to the YN system. Remarkably simple analytical expression for
the amplitude is obtained. Pronounced effects due to final state interaction
are predicted including the manifestation of the 2.13 GeV resonance.Comment: LaTeX, 13 page
\pi N scattering in relativistic baryon chiral perturbation theory revisited
We have analyzed pion-nucleon scattering using the manifestly relativistic
covariant framework of Infrared Regularization up to {\cal O}(q^3) in the
chiral expansion, where q is a generic small momentum. We describe the
low-energy phase shifts with a similar quality as previously achieved with
Heavy Baryon Chiral Perturbation Theory, \sqrt{s}\lesssim1.14 GeV. New values
are provided for the {\cal O}(q^2) and {\cal O}(q^3) low-energy constants,
which are compared with previous determinations. This is also the case for the
scattering lengths and volumes. Finally, we have unitarized the previous
amplitudes and as a result the energy range where data are reproduced increases
significantly.Comment: 26 pages, 5 figures, 5 table
‘Treading water but drowning slowly’: what are GPs’ experiences of living and working with mental illness and distress in England? A qualitative study
Objectives
This paper provides an in-depth account of general practitioners’ (GPs) experiences of living and working with mental illness and distress, as part of a wider study reporting the barriers and facilitators to help-seeking for mental illness and burn-out, and sources of stress/distress for GP participants.
Design
Qualitative study using in-depth interviews with 47 GP participants. The interviews were audio recorded, transcribed, anonymised and imported into NVivo V.11 to facilitate data management. Data were analysed using a thematic analysis employing the constant comparative method.
Setting
England.
Participants
A purposive sample of GP participants who self-identified as: (1) currently living with mental distress, (2) returning to work following treatment, (3) off sick or retired early as a result of mental distress or (4) without experience of mental distress. Interviews were conducted face to face or over the telephone.
Results
The findings report GP participants’ in-depth experiences of distress and mental illness with many recollecting their distressing experiences and significant psychological and physical symptoms relating to chronic stress, anxiety, depression and/or burn-out, and a quarter articulating thoughts of suicide. Many talked about their shame, humiliation and embarrassment at their perceived inability to cope with the stresses of their job and/or their symptoms of mental illness.
Conclusions
These findings paint a concerning picture of the situation affecting primary care doctors, with participants’ accounts suggesting there is a considerable degree of mental ill health and reduced well-being among GPs. The solutions are complex and lie in prevention and provision. There needs to be greater recognition of the components and cumulative effect of occupational stressors for doctors, such as the increasing workload and the clinical and emotional demands of the job, as well as the need for a culture shift within medicine to more supportive and compassionate work environments
Unusual features in the nonlinear microwave surface impedance of Y-Ba-Cu-O thin films
Striking features have been found in the nonlinear microwave (8 GHz) surface
impedance of high-quality YBaCuO thin films with comparable
low power characteristics [ and ]. The surface resistance is found to increase,
decrease, or remain independent of the microwave field (up to 60 mT)
at different temperatures and for different samples. However, the surface
reactance always follows the same functional form. Mechanisms which may
be responsible for the observed variations in and are briefly
discussed.Comment: 4 pages, 4 figure
Quasifree pion photoproduction on the deuteron in the region
Photo production of pions on the deuteron is studied in the spectator nucleon
model. The Born terms of the elementary production amplitude are determined in
pseudovector N coupling and supplied with a form factor. The
resonance is considered both in the and the channel. The parameters of
the resonance and the cutoff of the form factors are fixed on the
leading photoproduction multipoles. Results for total and differential cross
sections are compared with experimental data. Particular attention is paid to
the role of Pauli correlations of the final state nucleons in the quasifree
case. The results are compared with those for pion photoproduction on the
nucleon.Comment: 17 pages LateX2e including 5 postscript figure
Analytic Confinement and Regge Trajectories
A simple relativistic quantum field model with the Yukawa-type interaction is
considered to demonstrate that the analytic confinement of the constituent
("quarks") and carrier ("gluons") particles explains qualitatively the basic
dynamical properties of the spectrum of mesons considered as two-particle
stable bound states of quarks and gluons: the quarks and gluons are confined,
the glueballs represent bound states of massless gluons, the masses of mesons
are larger than the sum of the constituent quark masses and the Regge
trajectories of mesonic orbital excitations are almost linear.Comment: RevTeX, 16 pages, 3 figures and 2 table
Shear-free, Irrotational, Geodesic, Anisotropic Fluid Cosmologies
General relativistic anisotropic fluid models whose fluid flow lines form a
shear-free, irrotational, geodesic timelike congruence are examined. These
models are of Petrov type D, and are assumed to have zero heat flux and an
anisotropic stress tensor that possesses two distinct non-zero eigenvalues.
Some general results concerning the form of the metric and the stress-tensor
for these models are established. Furthermore, if the energy density and the
isotropic pressure, as measured by a comoving observer, satisfy an equation of
state of the form , with , then
these spacetimes admit a foliation by spacelike hypersurfaces of constant Ricci
scalar. In addition, models for which both the energy density and the
anisotropic pressures only depend on time are investigated; both spatially
homogeneous and spatially inhomogeneous models are found. A classification of
these models is undertaken. Also, a particular class of anisotropic fluid
models which are simple generalizations of the homogeneous isotropic
cosmological models is studied.Comment: 13 pages LaTe
Measuring longitudinal amplitudes for electroproduction of pseudoscalar mesons using recoil polarization in parallel kinematics
We propose a new method for measuring longitudinal amplitudes for
electroproduction of pseudoscalar mesons that exploits a symmetry relation for
polarization observables in parallel kinematics. This polarization technique
does not require variation of electron scattering kinematics and avoids the
major sources of systematic errors in Rosenbluth separation.Comment: intended for Phys. Rev. C as a Brief Repor
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