139 research outputs found
Proton-neutron symmetry in 92Zr, 94Mo with Skyrme interactions in a separable approximation
Starting from a Skyrme interaction we study the properties of the low-energy
spectrum of quadrupole excitations in 90,92Zr, 92,94Mo. The coupling between
one- and two-phonon terms in the wave functions of excited states are taken
into account. We use the finite-rank separable approximation which enables one
to perform the QRPA calculations in very large two-quasiparticle spaces. Our
results from the SGII Skyrme interaction in connection with the volume pairing
interaction are in reasonable agreement with experimental data. In particular,
we present the successful description of the M1 transition between low-energy
quadrupole excitations.Comment: 9 pages, 3 figure
Spreading widths of giant resonances in spherical nuclei: damped transient response
We propose the universal approach to describe spreading widths of monopole,
dipole and quadrupole giant resonances in heavy and superheavy spherical
nuclei. Our approach is based on the ideas of the random matrix distribution of
the coupling between one-phonon and two-phonon states generated in the random
phase approximation. We use the Skyrme interaction SLy4 as our model
Hamiltonian to create a single-particle spectrum and to analyze excited states
of the doubly magic nuclei Sn, Pb and 126. Our results
demonstrate that the universal approach enables to describe gross structure of
the spreading widths of the considered giant resonances.Comment: 6 pages, 2 figure
Microscopic Description of Isoscalar Giant Monopole Resonance in Ca
The properties of the isoscalar giant monopole resonance (ISGMR) for the
double magic Ca are analyzed in the framework of a microscopic model
based on Skyrme-type interactions. A method for simultaneously taking into
account the coupling between one-, two-, and three-phonon terms in the wave
functions of states has been developed. The inclusion of three-phonon
configurations leads to a substantial redistribution of the ISGMR strength to
lower energy states and also higher energy tail. Our results
demonstrate that the developed approach enables to us to describe a gross
structure of the ISGMR spreading width.Comment: 13 pages, 1 figure, accepted for publication in Physics of Atomic
Nucle
Two-phonon structures for beta-decay theory
The -decay rates of Ca have been studied within a microscopic
model, which is based on the Skyrme interaction T45 to construct
single-particle and phonon spaces. We observe a redistribution of the
Gamow-Teller strength due to the phonon-phonon coupling, considered in the
model. For Sc, the spin-parity of the ground state is found to be .
We predict that the half-life of Ca is 0.3 ms, while the total
probability of the emission is 6.1%. Additionally, the random
matrix theory has been applied to analyse the statistical properties of the
spectrum populated in the -decay to elucidate the obtained
results.Comment: 4 pages, 1 figure, proceedings of International Conference on Nuclear
Structure and Related Topics (NSRT18), June 3-9 2018, Burgas, Bulgari
Influence of complex configurations on properties of pygmy dipole resonance in neutron-rich Ca isotopes
Starting from the quasiparticle random phase approximation based on the
Skyrme interaction SLy5, we study the effects of phonon-phonon coupling~(PPC)
on the low-energy electric dipole response in Ca. Using the same set
of parameters we describe available experimental data for Ca and
give prediction for Ca. The inclusion of the PPC results in the
formation of low-energy states. There is an impact of the PPC effect on
low-energy ~strength of Ca. The PPC effect on the electric
dipole polarizability is discussed. We predict a strong increase of the summed
~strength below 10MeV, with increasing neutron number from Ca till
Ca.Comment: 11 pages, 10 figure
Structure of low-lying quadrupole states in nuclei near 132Sn
The properties of the low-lying 2^+ states in the even-even nuclei around
132Sn are studied within the quasiparticle random phase approximation. Starting
from a Skyrme interaction in the particle-hole channel and a density-dependent
zero-range interaction in the particle-particle channel, we use the finite rank
separable approach in our investigation. It is found that the fourth 2^+ state
in 132Te could be a good candidate for a mixed-symmetry state.Comment: 6 pages, 2 figures, proceedings of International Conference on
Nuclear Structure and Related Topics (NSRT09), June 2009, JINR, Dubna, Russi
Spreading widths of giant monopole resonance in the lead region: Random matrix approach
The microscopic calculation of the decay width of giant monopole resonance
(GMR) anticipates the mixing of one-phonon states with configurations of
increasing complexity. To this aim we develop the effective approach for
description of monopole excited states that are obtained in the quasiparticle
random phase approximation (QRPA), with regard of the coupling between one- and
two-phonon states. Based on the QRPA one-phonon states, we generate the
coupling and two-phonon states by means of the Gaussian orthogonal ensemble
(GOE) distribution. Within our approach the spreading width of the GMRs in
Pb are described by means of a random matrix approach on two
energy scales. It is demonstrated that the main contribution into the decay of
the GMR is determined by a small number of two-phonon states strongly coupled
to low-energy surface vibrations. While a vast majority of the coupling matrix
elements (that are small in value and following the GOE distribution) are
responsible for the fine structure of the GMR spreading width. A remarkable
agreement between the results of the full microscopic calculations (based on
QRPA phonons coupled by means of the microscopic coupling matrix elements with
calculated two-phonon states) with those of the developed approach confirms the
vitality of the proposed ideas.Comment: 8 pages, 7 figure
Influence of 2p-2h configurations on beta-decay rates
The effects of the phonon-phonon coupling on the beta-decay rates of
neutron-rich nuclei are studied in a microscopic model based on Skyrme-type
interactions. The approach uses a finite-rank separable approximation of the
Skyrme-type particle-hole (p-h) residual interaction. Very large
two-quasiparticle spaces can thus be treated. A redistribution of the
Gamow-Teller (G-T) strength is found due to the tensor correlations and the
2p-2h fragmentation of G-T states. As a result, the beta-decay half-lives are
decreased significantly. Using the Skyrme interaction SGII together with a
volume-type pairing interaction we illustrate this reduction effect by
comparing with available experimental data for the Ni isotopes and neutron-rich
N=50 isotones. We give predictions for 76Fe and 80Ni in comparison with the
case of the doubly-magic nucleus 78Ni which is an important waiting point in
the r-process.Comment: 8 pages, 6 figures, accepted for publication in Physical Review
Assessment of adherence to drug and non-drug treatments and its changes under the influence of an education program in patients with rheumatoid arthritis
Objective: to assess awareness of drug and non-drug treatments for rheumatoid arthritis (RA) and compliance in patients before and after their participation in an education program, as well as the survival of the knowledge and the need for retraining. Subjects and methods. The study included 43 patients with RA: 23 study group patients were trained according to an education program (Rheumatoid Arthritis Health School), 20 patients formed a control group. The education program consisted of 4 daily 90-min studies. Adherence to drug and non-drug treatments was assessed at baseline and at 3 and 6 months. Results. In the study group, the basic therapy remained stably high (about 100%) within 6 months. At 3 months after studies, nonsteroidal anti-inflammatory drugs could be discontinued in 23.8% (p < 0.05). After 6 months, the proportion of patients using laser therapy increased by 57.1% (p < 0.01) and accounted for 47.8%; the use of electric and ultrasound treatments showed a 55.6% increase (p < 0.01) and was 60.9%. The number of patients who were compliant to the procedures for shaping a correct functional stereotype increased by 14 and 10 times following 3 and 6 months (60.9% and 43.5%, respectively; p < 0.01). After 3 months, there was a rise in the number of patients using hand ortheses by 75.0% (30.4%; p < 0.01); knee ortheses by 50.0% (39.1%; p < 0.01); individual inner soles by 71.4% (52.2%; p < 0.01); and walking sticks and crutches by 60.0% (34.8%; p < 0.01). Following 6 months, the positive changes remained only after the relative use of inner soles (60.9%) and support means (34.8%; p < 0.05). The number of patients who regularly did physical activity increased by 5.3 (69.6%; р < 0.01) and 3.7 (47.8%; p < 0.01) times at 3 and 6 months, respectively. The trend in the control group was less pronounced, determining statistically significant differences between the groups in most indicators (р < 0.05). Conclusion. The education program retains high compliance to the basic therapy, reduces needs for symptomatic drugs, and enhances adherence to physiotherapy, methods for shaping a correct motor stereotype, orthesis wearing, and regular physical activity. The maximum positive result of the Rheumatoid Arthritis Health School was achieved after 3 months; this effect slightly diminished at 6 months. This necessitates retraining in the following 3-6 months
Clinical efficiency of an education program for patients with rheumatoid arthritis
Objective: to develop an education program for patients with rheumatoid arthritis (RA) and to evaluate its efficiency. Subjects and methods. The study included 43 patients with RA: 23 study group patients were trained according to an education program (Rheumatoid Arthritis Health School), 20 patients formed a control group. The education program consisted of 4 daily 90-min studies. The MDHAQ (R798—NP2) questionnaire was used to determine DAS 28, HAQ, RAPID 3 scores at baseline and following 6 months. Results. Six months after education, the study group showed reductions in DAS 28 by 1.33+0.26 scores (р < 0.05), HAQ by 0.91±0.54 (55.2%; р < 0.01), and RAPID 3 by 5.96±0.92 (49.9%; р < 0.01), anxiety level by 0.86±0.32 (54.4%; р < 0.05), depression by 0.87±0.61 (53.4%; р < 0.05), fatigability by 3.39±1.17 (47.5%; р < 0.05); sleep improved by 0.81±0.36 scores (54.7%; р < 0.05). Six months following education program participation, there was significantly more frequently a good DAS 28 response to treatment according to the EULAR criteria (52.2% versus 30.0% in the control group; р < 0.05), and the number of patients who reported health improvement increased by 8.5 times (р < 0.01). The changes in the control group were less pronounced, which determined statistically significant differences between the groups in most indicators (р < 0.05). Conclusion. The education program improves functional capacities and psychological status, assists in controlling the disease activity, and enhances the quality of life in patients with RA
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