282 research outputs found
The Triaxial Rotation Vibration Model in the Xe-Ba Region
The axial Rotation Vibration Model is here extended to describe also triaxial
equilibrium shapes with beta and gamma vibrations allowing for the interaction
between vibrations and rotations. This Triaxial Rotation Vibration Model (TRVM)
is applied to Xe and Ba isotopes with mass numbers between 120 and 130. This
area has recently been pointed out to be the O(6) limit of the Interacting
Boson Approximation (IBA). The present work shows that the TRVM can equally
well describe these nuclei concerning their excitation energies and E2
branching ratios.Comment: 11 pages, 2 figure
Coulomb plasmas in outer envelopes of neutron stars
Outer envelopes of neutron stars consist mostly of fully ionized, strongly
coupled Coulomb plasmas characterized by typical densities about 10^4-10^{11}
g/cc and temperatures about 10^4-10^9 K. Many neutron stars possess magnetic
fields about 10^{11}-10^{14} G. Here we briefly review recent theoretical
advances which allow one to calculate thermodynamic functions and electron
transport coefficients for such plasmas with an accuracy required for
theoretical interpretation of observations.Comment: 4 pages, 2 figures, latex2e using cpp2e.cls (included). Proc. PNP-10
Workshop, Greifswald, Germany, 4-9 Sept. 2000. Accepted for publication in
Contrib. Plasma Phys. 41 (2001) no. 2-
E(5), X(5), and Prolate to Oblate Shape Phase Transitions in Relativistic Hartree Bogoliubov Theory
Relativistic mean field theory with the NL3 force is used for producing
potential energy surfaces (PES) for series of isotopes suggested as exhibiting
critical point symmetries. Relatively flat PES are obtained for nuclei showing
the E(5) symmetry, while in nuclei corresponding to the X(5) case, PES with a
bump are obtained. The PES corresponding to the Pt chain of isotopes suggest a
transition from prolate to oblate shapes at 186-Pt.Comment: 21 pages, LaTeX, including 14 .eps figure
Preoperative Cognitive Impairment and Postoperative Delirium Predict Decline in Activities of Daily Living after Cardiac Surgery-A Prospective, Observational Cohort Study.
Cardiac surgery and subsequent treatment in the intensive care unit (ICU) has been shown to be associated with functional decline, especially in elderly patients. Due to the different assessment tools and assessment periods, it remains yet unclear what parameters determine unfavorable outcomes. This study sought to identify risk factors during the entire perioperative period and focused on the decline in activity of daily living (ADL) half a year after cardiac surgery. Follow-ups of 125 patients were available. It was found that in the majority of patients (60%), the mean ADL declined by 4.9 points (95% CI, -6.4 to -3.5; p < 0.000). In the "No decline" -group, the ADL rose by 3.3 points (2.0 to 4.6; p < 0.001). A multiple regression analysis revealed that preoperative cognitive impairment (MMSE ≤ 26; Exp(B) 2.862 (95%CI, 1.192-6.872); p = 0.019) and duration of postoperative delirium ≥ 2 days (Exp(B) 3.534 (1.094-11.411); p = 0.035) was independently associated with ADL decline half a year after the operation and ICU. Of note, preoperative ADL per se was neither associated with baseline cognitive function nor a risk factor for functional decline. We conclude that the preoperative assessment of cognitive function, rather than functional assessments, should be part of risk stratification when planning complex cardiosurgical procedures
Lifetime Measurements in 120Xe
Lifetimes for the lowest three transitions in the nucleus Xe have
been measured using the Recoil Distance Technique. Our data indicate that the
lifetime for the transition is more than a factor of
two lower than the previously adopted value and is in keeping with more recent
measurements performed on this nucleus. The theoretical implications of this
discrepancy and the possible reason for the erroneous earlier results are
discussed. All measured lifetimes in Xe, as well as the systematics of
the lifetimes of the 2 states in Xe isotopes, are compared with
predictions of various models. The available data are best described by the
Fermion Dynamic Symmetry Model (FDSM).Comment: 9 pages, RevTeX, 3 figures with Postscript file available on request
at [email protected], [email protected]. Submitted to Phys.
Rev.
Prealignment B(E2)-anomaly in 124Xe
Lifetimes of 17 levels of 124Xe were measured using the Recoil Distance Doppler Shift method. An anomalous E2-reduction was observed, starting at Iπ = 8+ and Iπ = 5+ in the groundstate and in the quasi-gamma band respectively. This anomaly is discussed in terms of the Interacting Boson Model
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