1,382 research outputs found
Nuclear and Neutron Star Radii
We investigate the correlation between nuclear neutron radii and the radius
of neutron stars. We use a well-established hadronic SU(3) model based on
chiral symmetry that naturally includes non-linear vector meson and scalar
meson - vector meson couplings. The relative strengths of the couplings modify
the nuclear isospin-dependent interactions. We study the dependence of nuclear
and neutron star radii on the coupling strengths. The relevance of the results
for parity-violating electron-nucleus scattering and the URCA process in
neutron stars is discussed
The âpatient voiceâ: patients who experience antidepressant withdrawal symptoms are often dismissed, or misdiagnosed with relapse, or a new medical condition
Background:
Stopping antidepressants commonly causes withdrawal symptoms, which can be severe and long-lasting. National Institute for Health and Care Excellence (NICE) guidance has been recently updated to reflect this; however, for many years withdrawal (discontinuation) symptoms were characterised as âusually mild and self-limiting over a weekâ. Consequently, withdrawal symptoms might have been misdiagnosed as relapse of an underlying condition, or new onset of another medical illness, but this has never been studied.
Method:
This paper outlines the themes emerging from 158 respondents to an open invitation to describe the experience of prescribed psychotropic medication withdrawal for petitions sent to British parliaments. The accounts include polypharmacy (mostly antidepressants and benzodiazepines) but we focus on antidepressants because of the relative lack of awareness about their withdrawal effects compared with benzodiazepines. Mixed method analysis was used, including a âlean thinkingâ approach to evaluate common failure points.
Results:
The themes identified include: a lack of information given to patients about the risk of antidepressant withdrawal; doctors failing to recognise the symptoms of withdrawal; doctors being poorly informed about the best method of tapering prescribed medications; patients being diagnosed with relapse of the underlying condition or medical illnesses other than withdrawal; patients seeking advice outside of mainstream healthcare, including from online forums; and significant effects on functioning for those experiencing withdrawal.
Discussion:
Several points for improvement emerge: the need for updating of guidelines to help prescribers recognise antidepressant withdrawal symptoms and to improve informed consent processes; greater availability of non-pharmacological options for managing distress; greater availability of best practice for tapering medications such as antidepressants; and the vital importance of patient feedback. Although the patients captured in this analysis might represent medication withdrawal experiences that are more severe than average, they highlight the current inadequacy of health care systems to recognise and manage prescribed drug withdrawal, and patient feedback in general
Neutrino Trapping in a Supernova and Ion Screening
Neutrino-nucleus elastic scattering is reduced in dense matter because of
correlations between ions. The static structure factor for a plasma of
electrons and ions is calculated from Monte Carlo simulations and parameterized
with a least squares fit. Our results imply a large increase in the neutrino
mean free path. This strongly limits the trapping of neutrinos in a supernova
by coherent neutral current interactions.Comment: 9 pages, 1 postscript figure using epsf.st
Finite gravitational action for higher derivative and stringy gravities
We generalize the local surface counterterm prescription suggested in
Einstein gravity for higher derivative (HD) and Weyl gravities. Explicitly, the
surface counterterm is found for three- and five-dimensional HD gravities. As a
result, the gravitational action for asymptotically AdS spaces is finite and
gravitational energy-momentum tensor is well-defined. The holographic trace
anomaly for d2 and d4 boundary (gauge) QFT dual to above HD gravity is
calculated from gravitational energy-momentum tensor. The calculation of AdS
black hole mass in HD gravity is presented within above prescrition. The
comparison with the standard prescription (using reference spacetime) is done.Comment: LaTeX file, 21 page
Branes, AdS gravitons and Virasoro symmetry
We consider travelling waves propagating on the anti-de Sitter (AdS)
background. It is pointed out that for any dimension d, this space of solutions
has a Virasoro symmetry with a non-zero central charge. This result is a
natural generalization to higher dimensions of the three-dimensional
Brown-Henneaux symmetry.Comment: 4 pages REVTe
Relativistic predictions of spin observables for exclusive proton knockout reactions
Within the framework of the relativistic distorted wave impulse approximation
(DWIA), we investigate the sensitivity of complete sets of polarization
transfer observables for exclusive proton knockout from the 3s,
2d and 2d states in Pb, at an incident laboratory
kinetic energy of 202 MeV, and for coincident coplanar scattering angles
(, ), to different distorting optical potentials,
finite-range (FR) versus zero-range (ZR) approximations to the DWIA, as well as
medium-modified meson-nucleon coupling constants and meson masses. Results are
also compared to the nonrelativistic DWIA predictions based on the
Schr\"{o}dinger equation.Comment: Submitted for publication to Physicical Review C, 23 pages, 7 figure
Neutron Star Structure and the Neutron Radius of 208Pb
We study relationships between the neutron-rich skin of a heavy nucleus and
the properties of neutron-star crusts. Relativistic effective field theories
with a thicker neutron skin in Pb have a larger electron fraction and a
lower liquid-to-solid transition density for neutron-rich matter. These
properties are determined by the density dependence of the symmetry energy
which we vary by adding nonlinear couplings between isoscalar and isovector
mesons. An accurate measurement of the neutron radius in Pb---via
parity violating electron scattering---may have important implications for the
structure of neutron stars.Comment: 5 pages 3 figures, added additional evidence of model independence,
Phys. Rev. Letters in pres
The Three-Dimensional BTZ Black Hole as a Cylindrical System in Four-Dimensional General Relativity
It is shown how to transform the three dimensional BTZ black hole into a four
dimensional cylindrical black hole (i.e., black string) in general relativity.
This process is identical to the transformation of a point particle in three
dimensions into a straight cosmic string in four dimensions.Comment: Latex, 9 page
Quark Coulomb Interactions and the Mass Difference of Mirror Nuclei
We study the Okamoto-Nolen-Schiffer (ONS) anomaly in the binding energy of
mirror nuclei at high density by adding a single neutron or proton to a quark
gluon plasma. In this high-density limit we find an anomaly equal to two-thirds
of the Coulomb exchange energy of a proton. This effect is dominated by quark
electromagnetic interactions---rather than by the up-down quark mass
difference. At normal density we calculate the Coulomb energy of neutron matter
using a string-flip quark model. We find a nonzero Coulomb energy because of
the neutron's charged constituents. This effect could make a significant
contribution to the ONS anomaly.Comment: 4 pages, 2 figs. sub. to Phys. Rev. Let
Self-consistent description of nuclear compressional modes
Isoscalar monopole and dipole compressional modes are computed for a variety
of closed-shell nuclei in a relativistic random-phase approximation to three
different parametrizations of the Walecka model with scalar self-interactions.
Particular emphasis is placed on the role of self-consistency which by itself,
and with little else, guarantees the decoupling of the spurious
isoscalar-dipole strength from the physical response and the conservation of
the vector current. A powerful new relation is introduced to quantify the
violation of the vector current in terms of various ground-state form-factors.
For the isoscalar-dipole mode two distinct regions are clearly identified: (i)
a high-energy component that is sensitive to the size of the nucleus and scales
with the compressibility of the model and (ii) a low-energy component that is
insensitivity to the nuclear compressibility. A fairly good description of both
compressional modes is obtained by using a ``soft'' parametrization having a
compression modulus of K=224 MeV.Comment: 28 pages and 10 figures; submitted to PR
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