652 research outputs found
Kerman-Klein-Donau-Frauendorf model for odd-odd nuclei: formal theory
The Kerman-Klein-Donau-Frauendorf (KKDF) model is a linearized version of the
Kerman-Klein (equations of motion) formulation of the nuclear many-body
problem. In practice, it is a generalization of the standard core-particle
coupling model that, like the latter, provides a description of the
spectroscopy of odd nuclei in terms of the properties of neighboring even
nuclei and of single-particle properties, that are the input parameters of the
model. A divers sample of recent applications attest to the usefulness of the
model. In this paper, we first present a concise general review of the
fundamental equations and properties of the KKDF model. We then derive a
corresponding formalism for odd-odd nuclei that relates their properties to
those of four neighboring even nuclei, all of which enter if one is to include
both multipole and pairing forces. We treat these equations in two ways. In the
first we make essential use of the solutions of the neighboring odd nucleus
problem, as obtained by the KKDF method. In the second, we relate the
properties of the odd-odd nuclei directly to those of the even nuclei. For both
choices, we derive equations of motion, normalization conditions, and an
expression for transition amplitudes. We also solve the problem of choosing the
subspace of physical solutions that arises in an equations of motion approach
that includes pairing interactions.Comment: 27 pages, Late
A Composite Chiral Pair of Rotational Bands in the odd-A Nucleus 135Nd
High-spin states in 135Nd were populated with the 110Pd(30Si,5n)135Nd
reaction at a 30Si bombarding energy of 133 MeV. Two Delta(I)=1 bands with
close excitation energies and the same parity were observed. These bands are
directly linked by Delta(I)=1 and Delta(I)=2 transitions. The chiral nature of
these two bands is confirmed by comparison with three-dimensional tilted axis
cranking calculations. This is the first observation of a three-quasiparticle
chiral structure and established the primarily geometric nature of this
phenomenon.Comment: 10 pages, 5 figures (1 in color), 1 table, submitted to Physics
Review Letters, written in REVTEX4 forma
On Words with the Zero Palindromic Defect
We study the set of finite words with zero palindromic defect, i.e., words
rich in palindromes. This set is factorial, but not recurrent. We focus on
description of pairs of rich words which cannot occur simultaneously as factors
of a longer rich word
Measurement of excited states in 40Si and evidence for weakening of the N=28 shell gap
Excited states in 40Si have been established by detecting gamma-rays
coincident with inelastic scattering and nucleon removal reactions on a liquid
hydrogen target. The low excitation energy, 986(5) keV, of the 2+[1] state
provides evidence of a weakening in the N=28 shell closure in a neutron-rich
nucleus devoid of deformation-driving proton collectivity.Comment: accepted for publication in PR
Differential Effects of Thiopeptide and Orthosomycin Antibiotics on Translational GTPases
SummaryThe ribosome is a major target in the bacterial cell for antibiotics. Here, we dissect the effects that the thiopeptide antibiotics thiostrepton (ThS) and micrococcin (MiC) as well as the orthosomycin antibiotic evernimicin (Evn) have on translational GTPases. We demonstrate that, like ThS, MiC is a translocation inhibitor, and that the activation by MiC of the ribosome-dependent GTPase activity of EF-G is dependent on the presence of the ribosomal proteins L7/L12 as well as the G′ subdomain of EF-G. In contrast, Evn does not inhibit translocation but is a potent inhibitor of back-translocation as well as IF2-dependent 70S-initiation complex formation. Collectively, these results shed insight not only into fundamental aspects of translation but also into the unappreciated specificities of these classes of translational inhibitors
Chirality in odd- nucleus Nd in particle rotor model
A particle rotor model is developed which couples several valence protons and
neutrons to a rigid triaxial rotor core. It is applied to investigating the
chirality in odd- nucleus Nd with configuration for the first time in a fully quantal approach.
For the two chiral sister bands, the observed energies and the and
values for the in-band as well as interband transitions are reproduced
excellently. Root mean square values of the angular momentum components and
their probability distributions are used for discussing in detail the chiral
geometry of the aplanar rotation and its evolution with angular momentum.
Chirality is found to change from a soft chiral vibration to nearly static
chirality at spin and back to another type of chiral vibration at
higher spin.Comment: 16 pages, 5 figure
Observation of isotonic symmetry for enhanced quadrupole collectivity in neutron-rich 62,64,66Fe isotopes at N=40
The transition rates for the 2_{1}^{+} states in 62,64,66Fe were studied
using the Recoil Distance Doppler-Shift technique applied to projectile Coulomb
excitation reactions. The deduced E2 strengths illustrate the enhanced
collectivity of the neutron-rich Fe isotopes up to N=40. The results are
interpreted by the generalized concept of valence proton symmetry which
describes the evolution of nuclear structure around N=40 as governed by the
number of valence protons with respect to Z~30. The deformation suggested by
the experimental data is reproduced by state-of-the-art shell calculations with
a new effective interaction developed for the fpgd valence space.Comment: 4 pages, 2 figure
Intercultural New Media Studies: The Next Frontier in intercultural Communication
New media (ICT\u27s) are transforming communication across cultures. Despite this revolution in cross cultural contact, communication researchers have largely ignored the impact of new media on intercultural communication. This groundbreaking article defines the parameters of a new field of inquiry called Intercultural New Media Studies (INMS), which explores the intersection between ICT\u27s and intercultural communication. Composed of two research areas—(1) new media and intercultural communication theory and (2) culture and new media—INMS investigates new digital theories of intercultural contact as well as refines and expands twentieth-century intercultural communication theories, examining their salience in a digital world. INMS promises to increase our understanding of intercultural communication in a new media age and is the next frontier in intercultural communication
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