42,502 research outputs found
Intestinal Microbial Ecology of Broilers Vaccinated and Challenged With Mixed Eimeria Species, and Supplemented with Essential Oil Blends
Intestinal microbiota is an important component in the development of defense mechanisms in the gut mucosa. This project determined the dynamics of intestinal microbial communities (MC) of broilers vaccinated at first day of age with live oocysts of Eimeria species and fed diets supplemented with 2 specific essential oil (EO) blends, Crina Poultry (CP) and Crina Alternate (CA). Five treatments were analyzed: 1) unmedicated-uninfected (UU) control; 2) unmedicated-infected (UI) control; 3) vaccinated with Advent cocci-vaccine and without feed additive (COV) supplements; 4) vaccinated with Advent and supplemented with CP; and 5) vaccinated with Advent and supplemented with CA. The EO blends were added at 100 ppm to the same basal diets. Chicks were gavage-infected at 19 d of age with Eimeria acervulina, Eimeria maxima, and Eimeria tenella. Duodenal, ileal, and cecal samples were taken from 12 birds per treatment just before the infection and 7 d after the challenge, pooled in 6 samples, and frozen. Denaturing gradient gel electrophoresis was used to examine PCR-amplified fragments of the bacterial 16S ribosomal DNA variable region. Results are presented as percentages of similarity coefficients (SC). Dendrograms of amplicon patterns indicated MC differences due to intestinal location, feed additives, and cocci infection. The EO blends CP and CA did affect MC in all gut sections. The cocci-infection caused drastic MC population shifts in duodenal, ileal, and cecal sections (36.7, 55.4, and 36.2% SC, respectively). The CP-supplemented birds had higher SC between pre- and postchallenge MC in duodenal and ileal (73.3, 81.8%) than COV (66.4, 66.5%). However, COV broilers had the smallest changes in cecal MC after infection (79.5% SC). We concluded that cocci-vaccination causes small changes in intestinal MC, but challenge causes drastic shifts. The EO blend supplementation modulates MC in cocci-vaccinated broilers, avoiding drastic shifts after a mixed coccidia infection. Correlations between MC dynamics and host responses are discussed
Langlands duality for finite-dimensional representations of quantum affine algebras
We describe a correspondence (or duality) between the q-characters of
finite-dimensional representations of a quantum affine algebra and its
Langlands dual in the spirit of q-alg/9708006 and 0809.4453. We prove this
duality for the Kirillov-Reshetikhin modules and their irreducible tensor
products. In the course of the proof we introduce and construct "interpolating
(q,t)-characters" depending on two parameters which interpolate between the
q-characters of a quantum affine algebra and its Langlands dual.Comment: 40 pages; several results and comments added. Accepted for
publication in Letters in Mathematical Physic
Langlands duality for representations of quantum groups
We establish a correspondence (or duality) between the characters and the
crystal bases of finite-dimensional representations of quantum groups
associated to Langlands dual semi-simple Lie algebras. This duality may also be
stated purely in terms of semi-simple Lie algebras. To explain this duality, we
introduce an "interpolating quantum group" depending on two parameters which
interpolates between a quantum group and its Langlands dual. We construct
examples of its representations, depending on two parameters, which interpolate
between representations of two Langlands dual quantum groups.Comment: 37 pages. References added. Accepted for publication in Mathematische
Annale
Zero sound density oscillations in Fermi-Bose mixtures
Within a mean field plus Random-Phase Approximation formalism, we investigate
the collective excitations of a three component Fermi-Bose mixture of K atoms,
magnetically trapped and subjected to repulsive s-wave interactions. We analyze
both the single-particle excitation and the density oscillation spectra created
by external multipolar fields, for varying fermion concentrations. The
formalism and the numerical output are consistent with the Generalized Kohn
Theorem for the whole multispecies system. The calculations give rise to
fragmented density excitation spectra of the fermion sample and illustrate the
role of the mutual interaction in the observed deviations of the bosonic
spectra with respect to Stringari's rule.Comment: 9 pages, 6 eps figures, submitted to Phys.Rev.
On the signature of superclusters and voids in the Integrated Sachs-Wolfe effect
Through a large ensemble of Gaussian realisations and a suite of large-volume
N-body simulations, we show that in a standard LCDM scenario, supervoids and
superclusters in the redshift range should leave a {\em small}
signature on the ISW effect of the order K. We perform aperture
photometry on WMAP data, centred on such superstructures identified from SDSS
LRGs, and find amplitudes at the level of 8 -- 11K -- thus confirming the
earlier work of Granett et al 2008. If we focus on apertures of the size
\sim3.6\degr, then our realisations indicate that LCDM is discrepant at the
level of . If we combine all aperture scales considered, ranging
from 1\degr--20\degr, then the discrepancy becomes , and it
further lowers to if only 30 superstructures are considered
in the analysis (being compatible with no ISW signatures at in this
case). Full-sky ISW maps generated from our N-body simulations show that this
discrepancy cannot be alleviated by appealing to Rees-Sciama mechanisms, since
their impact on the scales probed by our filters is negligible. We perform a
series of tests on the WMAP data for systematics. We check for foreground
contaminants and show that the signal does not display the correct dependence
on the aperture size expected for a residual foreground tracing the density
field. The signal also proves robust against rotation tests of the CMB maps,
and seems to be spatially associated to the angular positions of the supervoids
and superclusters. We explore whether the signal can be explained by the
presence of primordial non-Gaussianities of the local type. We show that for
models with \FNL=\pm100, whilst there is a change in the pattern of
temperature anisotropies, all amplitude shifts are well below K.Comment: 14 pages, 9 figures, matches accepted version in MNRA
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