1,078 research outputs found
Dynamical moment of inertia and quadrupole vibrations in rotating nuclei
The contribution of quantum shape fluctuations to inertial properties of
rotating nuclei has been analysed within the self-consistent one-dimensional
cranking oscillator model. It is shown that in even-even nuclei the dynamical
moment of inertia calculated in the mean field approximation is equivalent to
the Thouless-Valatin moment of inertia calculated in the random phase
approximation if and only if the self-consistent conditions for the mean field
are fulfilled.Comment: 4 pages, 2 figure
Removal of Spurious Admixture in a Self-consistent Theory of Adiabatic Large Amplitude Collective Motion
In this article we analyse, for a simple model, the properties of a practical
implementation of a fully self-consistent theory of adiabatic large-amplitude
collective motion using the local harmonic approach. We show how we can deal
with contaminations arising from spurious modes, caused by standard simplifying
approximations. This is done both at zero and finite angular momentum. We
analyse in detail the nature of the collective coordinate in regions where they
cross spurious modes and mixing is largest
The Long Journey from Ab Initio Calculations to Density Functional Theory for Nuclear Large Amplitude Collective Motion
At present there are two vastly different ab initio approaches to the
description of the the many-body dynamics: the Density Functional Theory (DFT)
and the functional integral (path integral) approaches. On one hand, if
implemented exactly, the DFT approach can allow in principle the exact
evaluation of arbitrary one-body observable. However, when applied to Large
Amplitude Collective Motion (LACM) this approach needs to be extended in order
to accommodate the phenomenon of surface-hoping, when adiabaticity is strongly
violated and the description of a system using a single (generalized) Slater
determinant is not valid anymore. The functional integral approach on the other
hand does not appear to have such restrictions, but its implementation does not
appear to be straightforward endeavor. However, within a functional integral
approach one seems to be able to evaluate in principle any kind of observables,
such as the fragment mass and energy distributions in nuclear fission. These
two radically approaches can likely be brought brought together by formulating
a stochastic time-dependent DFT approach to many-body dynamics.Comment: 9 page
Integral representation of the RPA correlation energy
Using the spectral function F'(z)/F(z) the RPA correlation energy and other
properties of a finite system can be written as a contour integral in a compact
way. This yields a transparent expression and reduces drastically the numerical
efforts for obtaining reliable values. The method applied to pairing vibrations
in rotating nuclei as an illustrative example.Comment: 9 pages, 2 figures (eps files
Level Structure of 103Ag at high spins
High spin states in Ag were investigated with the Gammasphere array,
using the Ge(Cl,)Ag reaction at an incident beam
energy of 135 MeV. A =1 sequence with predominantly magnetic
transitions and two nearly-degenerate doublet bands have been
observed. The dipole band shows a decreasing trend in the strength as
function of spin, a well established feature of magnetic bands. The
nearly-degenerate band structures satisfy the three experimental signatures of
chirality in the nuclei; however microscopic calculations are indicative of a
magnetic phenomeno
Extension of continuum time-dependent Hartree-Fock method to proton states
This paper deals with the solution of the spherically symmetric time-dependent Hartree-Fock approximation applied to nuclear giant monopole resonances in the small amplitude regime. The problem is spatially unbounded as the resonance state is in the continuum. The practical requirement to perform the calculation in a finite-sized spatial region yields an artificial boundary, which is not present physically. The question of how to ensure the boundary does not interfere with the internal solution, while keeping the overall calculation time low is studied. Here we propose an absorbing boundary condition scheme to handle the conflict. The derivation, via a Laplace transform method, and implementation is described. An inverse Laplace transform required by the absorbing boundaries is calculated using a method of non-linear least squares. The accuracy and efficiency of the scheme is tested and results presented to support the case that they are a effective way of handling the artificial boundary
The nuclear energy density functional formalism
The present document focuses on the theoretical foundations of the nuclear
energy density functional (EDF) method. As such, it does not aim at reviewing
the status of the field, at covering all possible ramifications of the approach
or at presenting recent achievements and applications. The objective is to
provide a modern account of the nuclear EDF formalism that is at variance with
traditional presentations that rely, at one point or another, on a {\it
Hamiltonian-based} picture. The latter is not general enough to encompass what
the nuclear EDF method represents as of today. Specifically, the traditional
Hamiltonian-based picture does not allow one to grasp the difficulties
associated with the fact that currently available parametrizations of the
energy kernel at play in the method do not derive from a genuine
Hamilton operator, would the latter be effective. The method is formulated from
the outset through the most general multi-reference, i.e. beyond mean-field,
implementation such that the single-reference, i.e. "mean-field", derives as a
particular case. As such, a key point of the presentation provided here is to
demonstrate that the multi-reference EDF method can indeed be formulated in a
{\it mathematically} meaningful fashion even if does {\it not} derive
from a genuine Hamilton operator. In particular, the restoration of symmetries
can be entirely formulated without making {\it any} reference to a projected
state, i.e. within a genuine EDF framework. However, and as is illustrated in
the present document, a mathematically meaningful formulation does not
guarantee that the formalism is sound from a {\it physical} standpoint. The
price at which the latter can be enforced as well in the future is eventually
alluded to.Comment: 64 pages, 8 figures, submitted to Euroschool Lecture Notes in Physics
Vol.IV, Christoph Scheidenberger and Marek Pfutzner editor
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An exploration of patient-reported symptoms in systemic lupus erythematosus and the relationship to health-related quality of life
Objective: The aim of this study was to explore the most distressing symptoms of systemic lupus erythematosus (SLE) and determine how these relate to health-related quality of life (HRQoL), anxiety/depression, patient demographics and disease characteristics (duration, activity, organ damage).
Methods: In a cross-sectional study, patients with SLE (n=324, age 18-84 years) gave written responses regarding which SLE-related symptoms they experienced as most difficult. Their responses were categorized. Within each category, patients reporting a specific symptom were compared with non-reporters and analyzed for patient demographics, disease duration, results from the questionnaires: Medical Outcomes Study Short-Form 36, Hospital Anxiety and Depression Scale, Systemic Lupus Activity Measure, SLE disease activity index and the Systemic Lupus International Collaboration Clinics/American College of Rheumatology damage index.
Results: 23 symptom categories were identified. Fatigue (51%), Pain (50%) and Musculoskeletal distress (46%) were most frequently reported. Compared with non-reporters, only patients reporting Fatigue showed statistically significant impact on both mental and physical components of HRQoL.. Patients with no present symptoms (10%) had higher HRQoL (p<0.001) and lower levels of depression (p<0.001), anxiety (p<0.01) and disease activity (SLAM) (p<0.001).
Conclusion: Fatigue, pain or musculoskeletal distress dominated the reported symptoms in approximately half of the patients. Only patients reporting Fatigue scored lower on both mental and physical aspects of HRQoL. Our results emphasize the need for further support and interventions to ease the symptom load and improve HRQoL in patients with SLE. Our findings further indicate that this need is particularly urgent for patients with symptoms of pain or fatigue
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