237 research outputs found
Properties of Be and C deduced from the folding--potential model
The -- differential cross sections are analyzed in the
optical model using a double--folded potential. With the knowledge of this
potential bound and resonance--state properties of --cluster states in
Be and C as well as astrophysical S--factors of
He(,)Be and Be(,)C are
calculated. --widths and B(E2)--values are deduced.Comment: 2 pages LaTeX, 2 figures can be obtained from the author
Orbital and Spin Magnetic Dipole Strength in a shell model calculation with = excitations: ^8\mbox{Be}
The magnetic dipole strength and energy-weighted strength distribution is
calculated in ^8\mbox{Be}, as well as the separate orbit and spin parts. All
= excitations over and above (and including) the configuration
are included. The interaction has a central, two-body spin-orbit
and a tensor part. The energy- independent and energy-weighted {\underline
orbital} strength distribution is remarkably insensitive to the presence or
absence of the spin-orbit or tensor interaction -not so the spin strength. The
energy-weighted strength distribution can be divided into a low enegy and a
high energy part. The high energy orbital part is somewhat less but close to
the low energy part, in fair agreement with a prediction that they be equal by
de Guerra and Zamick and by Nojarov. There is a wide plateau separating the low
energy part from the high energy part.Comment: 12 pages (4 figs/on request) \#RU944
Quantum Monte Carlo calculations of nuclei
We report on quantum Monte Carlo calculations of the ground and low-lying
excited states of nuclei using realistic Hamiltonians containing the
Argonne two-nucleon potential alone or with one of several
three-nucleon potentials, including Urbana IX and three of the new Illinois
models. The calculations begin with correlated many-body wave functions that
have an -like core and multiple p-shell nucleons, -coupled to the
appropriate quantum numbers for the state of interest. After
optimization, these variational trial functions are used as input to a Green's
function Monte Carlo calculation of the energy, using a constrained path
algorithm. We find that the Hamiltonians that include Illinois three-nucleon
potentials reproduce ten states in Li, Be, Be, and B with
an rms deviation as little as 900 keV. In particular, we obtain the correct
3 ground state for B, whereas the Argonne alone or with
Urbana IX predicts a 1 ground state. In addition, we calculate isovector
and isotensor energy differences, electromagnetic moments, and one- and
two-body density distributions.Comment: 28 pages, 12 tables, 7 figure
Alpha scattering and capture reactions in the A = 7 system at low energies
Differential cross sections for He- scattering were measured in
the energy range up to 3 MeV. These data together with other available
experimental results for He and H scattering were
analyzed in the framework of the optical model using double-folded potentials.
The optical potentials obtained were used to calculate the astrophysical
S-factors of the capture reactions HeBe and
HLi, and the branching ratios for the transitions into
the two final Be and Li bound states, respectively. For
HeBe excellent agreement between calculated and
experimental data is obtained. For HLi a value
has been found which is a factor of about 1.5 larger than the adopted value.
For both capture reactions a similar branching ratio of has been obtained.Comment: submitted to Phys.Rev.C, 34 pages, figures available from one of the
authors, LaTeX with RevTeX, IK-TUW-Preprint 930540
Beyond Implications and Applications: the Story of ‘Safety by Design’
Using long-term anthropological observations at the Center for Biological and Environmental Nanotechnology in Houston, Texas, the article demonstrates in detail the creation of new objects, new venues and new modes of veridiction which have reoriented the disciplines of materials chemistry and nanotoxicology. Beginning with the confusion surrounding the meaning of ‘implications’ and ‘applications’ the article explores the creation of new venues (CBEN and its offshoot the International Council on Nanotechnology); it then demonstrates how the demands for a responsible, safe or ethical science were translated into new research and experiment in and through these venues. Finally it shows how ‘safety by design’ emerged as a way to go beyond implications and applications, even as it introduced a whole new array of controversies concerning its viability, validity and legitimacy
Correlations in a Many-Body Calculation of Li
A many-body calculation of Li is presented where the only input is the
well-tested, finite-range {\it D1S} effective interaction of {\it Gogny}.
Pairing correlations are included in a constrained Hartree-Fock-Bogolyubov
calculation, while long-range collective correlations are introduced using a
GCM derived calculation. Correlations are found to play an important role in
describing Li. A substantive underlying Li core of Li is
found, which has a different density profile than a free Li nucleus. This
may have significant implications in the use of a three-body framework in
studies of Li.Comment: 23 pages typeset in revtex 2.0 with 8 postscript figures in
accompanying uuencoded fil
Bacteriocin as Weapons in the Marine Animal-Associated Bacteria Warfare: Inventory and Potential Applications as an Aquaculture Probiotic
As the association of marine animals with bacteria has become more commonly recognized, researchers have increasingly questioned whether these animals actually produce many of the bioactive compounds originally isolated from them. Bacteriocins, ribosomally synthesized antibiotic peptides, constitute one of the most potent weapons to fight against pathogen infections. Indeed, bacteriocinogenic bacteria may prevent pathogen dissemination by occupying the same ecological niche. Bacteriocinogenic strains associated with marine animals are a relevant source for isolation of probiotics. This review draws up an inventory of the marine bacteriocinogenic strains isolated from animal-associated microbial communities, known to date. Bacteriocin-like inhibitory substances (BLIS) and fully-characterized bacteriocins are described. Finally, their applications as probiotics in aquaculture are discussed
Phage Therapy and Photodynamic Therapy: Low Environmental Impact Approaches to Inactivate Microorganisms in Fish Farming Plants
Owing to the increasing importance of aquaculture to compensate for the progressive worldwide reduction of natural fish and to the fact that several fish farming plants often suffer from heavy financial losses due to the development of infections caused by microbial pathogens, including multidrug resistant bacteria, more environmentally-friendly strategies to control fish infections are urgently needed to make the aquaculture industry more sustainable. The aim of this review is to briefly present the typical fish farming diseases and their threats and discuss the present state of chemotherapy to inactivate microorganisms in fish farming plants as well as to examine the new environmentally friendly approaches to control fish infection namely phage therapy and photodynamic antimicrobial therapy
Infectious hematopoietic necrosis virus (IHNV) persistence in Sockeye Salmon: influence on brain transcriptome and subsequent response to the viral mimic poly(I:C)
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