1,126 research outputs found
Effects of a seaweed extract on weanling pig growth performance and immune function during an acute enteric disease challenge
A total of 95 pigs (initially 15 lb and 17
d of age) was used in a 28 d growth trial to
determine the effects of Ascophyllum nodosum seaweed extract (ANOD) on weanling pig growth performance and immune function in response to enteric disease challenge with Salmonella typhimurium (ST). Experimental treatments were arranged in a 2 x 4 factorial with main effects of disease challenge (control vs. ST challenge) and dietary addition of ANOD (0, 0.5, 1.0, and 2.0% of diet). Results suggest little beneficial effect of dietary ANOD on growth performance or immune response in the presence or absence of ST challenge
Weak and strong electronic correlations in Fe superconductors
In this chapter the strength of electronic correlations in the normal phase
of Fe-superconductors is discussed. It will be shown that the agreement between
a wealth of experiments and DFT+DMFT or similar approaches supports a scenario
in which strongly-correlated and weakly-correlated electrons coexist in the
conduction bands of these materials. I will then reverse-engineer the realistic
calculations and justify this scenario in terms of simpler behaviors easily
interpreted through model results. All pieces come together to show that Hund's
coupling, besides being responsible for the electronic correlations even in
absence of a strong Coulomb repulsion is also the origin of a subtle emergent
behavior: orbital decoupling. Indeed Hund's exchange decouples the charge
excitations in the different Iron orbitals involved in the conduction bands
thus causing an independent tuning of the degree of electronic correlation in
each one of them. The latter becomes sensitive almost only to the offset of the
orbital population from half-filling, where a Mott insulating state is
invariably realized at these interaction strengths. Depending on the difference
in orbital population a different 'Mottness' affects each orbital, and thus
reflects in the conduction bands and in the Fermi surfaces depending on the
orbital content.Comment: Book Chapte
Effects of a quillaja saponaria extract on weanling pig growth performance and immune function during an acute enteric disease challenge
A total of 96 pigs (initially 19 lb and 17 d of age) was used in a 28 d growth trial to
determine the effects of Quillaja saponaria
(QS) extract on weanling pig growth performance and immune function in response to enteric disease challenge with Salmonella
typhimurium (ST). Experimental treatments
were arranged in a 2 × 4 factorial with main
effects of disease challenge (control vs. ST
challenge) and dietary addition of QS (0, 4,
8, or 16 oz/ton). The results suggest little
beneficial effect of QS on growth performance
or immune response in the presence or absence of ST challenge
H2O2 Enables Convenient Removal of RAFT End-Groups from Block Copolymer Nano-Objects Prepared via Polymerization-Induced Self-Assembly in Water
RAFT-synthesized polymers are typically colored and malodorous due to the presence of the sulfur-based RAFT
end-group(s). In principle, RAFT end-groups can be removed by treating molecularly dissolved copolymer chains with excess
free radical initiators, amines, or oxidants. Herein we report a convenient method for the removal of RAFT end-groups from
aqueous dispersions of diblock copolymer nano-objects using H2O2. This oxidant is relatively cheap, has minimal impact on the
copolymer morphology, and produces benign side products that can be readily removed via dialysis. We investigate the efficiency
of end-group removal for various diblock copolymer nano-objects prepared with either dithiobenzoate- or trithiocarbonate-based
RAFT chain transfer agents. The advantage of using UV GPC rather than UV spectroscopy is demonstrated for assessing both
the kinetics and extent of end-group removal
Coherent States of the q--Canonical Commutation Relations
For the -deformed canonical commutation relations for in some Hilbert
space we consider representations generated from a vector
satisfying , where .
We show that such a representation exists if and only if .
Moreover, for these representations are unitarily equivalent
to the Fock representation (obtained for ). On the other hand
representations obtained for different unit vectors are disjoint. We
show that the universal C*-algebra for the relations has a largest proper,
closed, two-sided ideal. The quotient by this ideal is a natural -analogue
of the Cuntz algebra (obtained for ). We discuss the Conjecture that, for
, this analogue should, in fact, be equal to the Cuntz algebra
itself. In the limiting cases we determine all irreducible
representations of the relations, and characterize those which can be obtained
via coherent states.Comment: 19 pages, Plain Te
Cold event in the South Atlantic Bight during summer of 2003: Model simulations and implications
A set of model simulations are used to determine the principal forcing mechanisms that resulted in anomalously cold water in the South Atlantic Bight (SAB) in the summer of 2003. Updated mass field and elevation boundary conditions from basin-scale Hybrid Coordinate Ocean Model (HYCOM) simulations are compared to climatological forcing to provide offshore and upstream influences in a one-way nesting sense. Model skill is evaluated by comparing model results with observations of velocity, water level, and surface and bottom temperature. Inclusion of realistic atmospheric forcing, river discharge, and improved model dynamics produced good skill on the inner shelf and midshelf. The intrusion of cold water onto the shelf occurred predominantly along the shelf-break associated with onshore flow in the southern part of the domain north of Cape Canaveral (29° to 31.5°). The atmospheric forcing (anomalously strong and persistent upwelling-favorable winds) was the principal mechanism driving the cold event. Elevated river discharge increased the level of stratification across the inner shelf and midshelf and contributed to additional input of cold water into the shelf. The resulting pool of anomalously cold water constituted more than 50% of the water on the shelf in late July and early August. The excess nutrient flux onto the shelf associated with the upwelling was approximated using published nitrate-temperature proxies, suggesting increased primary production during the summer over most of the SAB shelf
Linear stability analysis of transverse dunes
Sand-moving winds blowing from a constant direction in an area of high sand
availability form transverse dunes, which have a fixed profile in the direction
orthogonal to the wind. Here we show, by means of a linear stability analysis,
that transverse dunes are intrinsically unstable. Any along-axis perturbation
on a transverse dune amplify in the course of dune migration due to the
combined effect of two main factors, namely: the lateral transport through
avalanches along the dune's slip-face, and the scaling of dune migration
velocity with the inverse of the dune height. Our calculations provide a
quantitative explanation for recent observations from experiments and numerical
simulations, which showed that transverse dunes moving on the bedrock cannot
exist in a stable form and decay into a chain of crescent-shaped barchans.Comment: 8 pages, 4 figure
Quantum lattice fluctuations in a frustrated Heisenberg spin-Peierls chain
As a simple model for spin-Peierls systems we study a frustrated Heisenberg
chain coupled to optical phonons. In view of the anorganic spin-Peierls
compound CuGeO3 we consider two different mechanisms of spin-phonon coupling.
Combining variational concepts in the adiabatic regime and perturbation theory
in the anti-adiabatic regime we derive effective spin Hamiltonians which cover
the dynamical effect of phonons in an approximate way. Ground-state phase
diagrams of these models are determined, and the effect of frustration is
discussed. Comparing the properties of the ground state and of low-lying
excitations with exact diagonalization data for the full quantum spin phonon
models, good agreement is found especially in the anti-adiabatic regime.Comment: 9 pages, 7 figures included, submitted to Phys. Rev.
Centrifugal stretching from lifetime measurements in the 170Hf ground state band
Centrifugal stretching in the deformed rare-earth nucleus 170Hf is investigated using high-precision lifetime measurements, performed with the New Yale Plunger Device at Wright Nuclear Structure Laboratory, Yale University. Excited states were populated in the fusion-evaporation reaction 124Sn(50Ti,4n)170Hf at a beam energy of 195 MeV. Recoil distance doppler shift data were recorded for the ground state band through the J=16+ level. The measured B(E2) values and transition quadrupole moments improve on existing data and show increasing β deformation in the ground state band of 170Hf. The results are compared to descriptions by a rigid rotor and by the confined β-soft rotor model. © 2013 American Physical Society
Low temperature electronic properties of Sr_2RuO_4 II: Superconductivity
The body centered tetragonal structure of Sr_2RuO_4 gives rise to umklapp
scattering enhanced inter-plane pair correlations in the d_{yz} and d_{zx}
orbitals. Based on symmetry arguments, Hund's rule coupling, and a bosonized
description of the in-plane electron correlations the superconducting order
parameter is found to be a orbital-singlet spin-triplet with two spatial
components. The spatial anisotropy is 7%. The different components of the order
parameter give rise to two-dimensional gapless fluctuations. The phase
transition is of third order. The temperature dependence of the pair density,
specific heat, NQR, Knight shift, and susceptibility are in agreement with
experimental results.Comment: 20 pages REVTEX, 3 figure
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