655 research outputs found
Development and Application of Operational Techniques for the Inventory and Monitoring of Resources and Uses for the Texas Coastal Zone
There are no author-identified significant results in this report
One-neutron knockout from Ni
The single-particle structure of Ni and level structure of Ni
were investigated with the \mbox{Be (Ni,Ni+)} reaction at 73 MeV/nucleon. An inclusive cross
section of 41.4(12) mb was obtained for the reaction, compared to a theoretical
prediction of 85.4 mb, hence only 48(2)% of the theoretical cross section is
exhausted. This reduction in the observed spectroscopic strength is consistent
with that found for lighter well-bound nuclei. One-neutron removal
spectroscopic factors of 0.58(11) to the ground state and 3.7(2) to all excited
states of Ni were deduced.Comment: Phys. Rev. C, accepte
Horn Fly Control and Growth Implants are Effective Strategies for Heifers Grazing Flint Hills Pasture
Horn flies (Haematobia irritans (L.)) are considered the most important external parasite that negatively affects pasture-based beef systems with losses estimated to exceed $1 billion annually to the U.S. beef industry. Control strategies have relied heavily on insecticide applications to control horn flies and are implemented when the economic threshold of 200 flies/animal have been exceeded. When horn fly populations are maintained below 200 flies/animal by treating them with insecticides then the level of stress annoyance behaviors such as leg stomping, head throwing, and skin twitching decreases while grazing increases. While most stocker operators utilize some type of fly control these are rarely used as a single pharmaceutical technology to aid in performance of the animals. Additional pharmaceutical technologies are utilized in combination of others, with the use of de-wormers and implants showing the largest impact with performance of stockers. The objective of this study was to compare a commercial injectable insecticide, LongRange, to an insecticidal ear tag for horn fly control and determine the impact of weight performance on stockers when fly control technologies were used in combination with implants versus no implants
Measurement of E2 Transitions in the Coulomb Dissociation of 8B
In an effort to understand the implications of Coulomb dissociation
experiments for the determination of the 7Be(p,gamma)8B reaction rate,
longitudinal momentum distributions of 7Be fragments produced in the Coulomb
dissociation of 44 and 81 MeV/nucleon 8B beams on a Pb target were measured.
These distributions are characterized by asymmetries interpreted as the result
of interference between E1 and E2 transition amplitudes in the Coulomb breakup.
At the lower beam energy, both the asymmetries and the measured cross sections
are well reproduced by perturbation theory calculations, allowing a
determination of the E2 strength.Comment: 8 pages, 3 figure
Multiband theory of multi-exciton complexes in self-assembled quantum dots
We report on a multiband microscopic theory of many-exciton complexes in
self-assembled quantum dots. The single particle states are obtained by three
methods: single-band effective-mass approximation, the multiband
method, and the tight-binding method. The electronic structure calculations are
coupled with strain calculations via Bir-Pikus Hamiltonian. The many-body wave
functions of electrons and valence holes are expanded in the basis of
Slater determinants. The Coulomb matrix elements are evaluated using statically
screened interaction for the three different sets of single particle states and
the correlated -exciton states are obtained by the configuration interaction
method. The theory is applied to the excitonic recombination spectrum in
InAs/GaAs self-assembled quantum dots. The results of the single-band
effective-mass approximation are successfully compared with those obtained by
using the of and tight-binding methods.Comment: 10 pages, 8 figure
S17(0) Determined from the Coulomb Breakup of 83 MeV/nucleon 8B
A kinematically complete measurement was made of the Coulomb dissociation of
8B nuclei on a Pb target at 83 MeV/nucleon. The cross section was measured at
low relative energies in order to infer the astrophysical S factor for the
7Be(p,gamma)8B reaction. A first-order perturbation theory analysis of the
reaction dynamics including E1, E2, and M1 transitions was employed to extract
the E1 strength relevant to neutrino-producing reactions in the solar interior.
By fitting the measured cross section from Erel = 130 keV to 400 keV, we find
S17(0) = 17.8 (+1.4, -1.2) eV b
Production cross sections of neutron rich isotopes from a 82Se beam
Production cross sections for neutron-rich nuclei from the fragmentation of a
82Se beam at 139 MeV/u were measured. The longitudinal momentum distributions
of 122 neutron-rich isotopes of elements were determined by
varying the target thickness. Production cross sections with beryllium and
tungsten targets were determined for a large number of nuclei including several
isotopes first observed in this work. These are the most neutron-rich nuclides
of the elements (64Ti, 67V, 69Cr, 72Mn). One event was
registered consistent with 70Cr, and another one with 75Fe. A one-body Qg
systematics is used to describe the production cross sections based on thermal
evaporation from excited prefragments. The current results confirm those of our
previous experiment with a 76Ge beam: enhanced production cross sections for
neutron-rich fragments near Z=20.Comment: Talk given at the 11th International Conference on Nucleus-Nucleus
Collisions (NN2012), San Antonio, Texas, USA, May 27-June 1, 2012. To appear
in the NN2012 Proceedings in Journal of Physics: Conference Series (JPCS
Measurement of the Gamow-Teller Strength Distribution in 58Co via the 58Ni(t,3He) reaction at 115 MeV/nucleon
Electron capture and beta decay play important roles in the evolution of
pre-supernovae stars and their eventual core collapse. These rates are normally
predicted through shell-model calculations. Experimentally determined strength
distributions from charge-exchange reactions are needed to test modern
shell-model calculations. We report on the measurement of the Gamow-Teller
strength distribution in 58Co from the 58Ni(t,3He) reaction with a secondary
triton beam of an intensity of ~10^6 pps at 115 MeV/nucleon and a resolution of
\~250 keV. Previous measurements with the 58Ni(n,p) and the 58Ni(d,2He)
reactions were inconsistent with each other. Our results support the latter. We
also compare the results to predictions of large-scale shell model calculations
using the KB3G and GXPF1 interactions and investigate the impact of differences
between the various experiments and theories in terms of the weak rates in the
stellar environment. Finally, the systematic uncertainties in the normalization
of the strength distribution extracted from 58Ni(3He,t) are described and turn
out to be non-negligible due to large interferences between the dL=0, dS=1
Gamow-Teller amplitude and the dL=2, dS=1 amplitude.Comment: 14 pages, 8 figure
Moving lessons: teaching sociology through embodied learning in the HE classroom
This chapter outlines an approach to classroom teaching that makes use of physical movement alongside more traditional lecturing methods when delivering lessons on abstract theoretical material. It develops the notion of embodied learning as a 'physical metaphor', outlining some examples of this practice that we have used in our recent work with a class of first year undergraduates. We argue that conceptualising students as embodied subjects, whose capacity to learn extends through and beyond their physical selves, educators are able to enhance classroom delivery by diversifying teaching activities and creating opportunities for enjoyable and memorable learning experiences. We advocate the reflexive, contextually-sensitive and level-
appropriate use of this method, arguing that despite some limitations it can animate students' understanding of academic ideas in uniquely personalised ways
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