3,344 research outputs found
Bloat in Ruminants: The Cell Rupture Hypothesis
An alfalfa (Medicago sativa L.) cultivar with a low initial rate of digestion (LIRD), AC Grazeland B, was developed to test the hypothesis that the rate of cell rupture was a cause of frothy bloat in cattle or sheep. The amount of cell wall increases and digestibility declines as plants mature. Thus the cell rupture theory also predicts that the bloat potential of alfalfa is related to maturity. This study compared the digestibility of cell walls (NDF) in LIRD cultivars with that of a standard, Beaver, in relation to maturity and bloat incidence. Fresh alfalfa was fed to wethers during two experiments. NDF was greater (P#.05) in Beaver (43.9%) than the less mature LIRD cultivar (41.1%) during Experiment 1. The digestibility of NDF was greater (P#.05) in the LIRD cultivar (48.4%; Beaver = 44.5%) during Experiment 2, when both cultivars were in vegetative stages of development but NDF digestibility was lower (P#.05) when the cultivars had matured to the bud stage (LIRD=37.1%; Beaver=48.4%). Bloat incidence did not differ between cultivars at the same stage of development. The number of bloats declined as the alfalfa matured, an effect which was attributed to the barrier to microbial invasion created by increasing amounts of cell wall and reduced cell wall digestibility. The cell rupture hypothesis of frothy bloat was supported by these results demonstrating that alfalfa maturity plays a key role in bloat etiology
Bacterial Cholangitis, Cholecystitis, or both in Dogs
BACKGROUND: Bacterial cholangitis and cholecystitis are rarely reported, poorly characterized diseases in the dog. OBJECTIVES: To characterize the clinical features of these conditions. ANIMALS: Twenty‐seven client‐owned dogs with bacterial cholangitis, cholecystitis, or both. METHODS: Multicenter, retrospective cases series of dogs with bacterial cholangitis, cholecystitis, or both, presenting January 2000 to June 2011 to 4 Veterinary Schools in Ireland/United Kingdom. Interrogation of hospital databases identified all cases with the inclusion criteria; histopathologically confirmed cholangitis or cholecystitis and bile culture/cytology results supporting a bacterial etiology. RESULTS: Twenty‐seven dogs met the inclusion criteria with approximately 460 hepatitis cases documented over the same study period. Typical clinical pathology findings were increases in liver enzyme activities (25/26), hyperbilirubinemia (20/26), and an inflammatory leukogram (21/24). Ultrasound findings, although nonspecific, aided decision‐making in 25/26 cases. The most frequent hepatobiliary bacterial isolates were Escherichia coli (n = 17; 16 cases), Enterococcus spp. (n = 8; 6 cases), and Clostridium spp. (n = 5; 5 cases). Antimicrobial resistance was an important feature of aerobic isolates; 10/16 E. coli isolates resistant to 3 or more antimicrobial classes. Biliary tract rupture complicated nearly one third of cases, associated with significant mortality (4/8). Discharged dogs had a guarded to fair prognosis; 17/18 alive at 2 months, although 5/10 re‐evaluated had persistent liver enzyme elevation 2–12 months later. CONCLUSION AND CLINICAL SIGNIFICANCE: Bacterial cholangitis and cholecystitis occur more frequently than suggested by current literature and should be considered in dogs presenting with jaundice and fever, abdominal pain, or an inflammatory leukogram or with ultrasonographic evidence of gallbladder abnormalities
An experimental study of the rearrangements of valence protons and neutrons amongst single-particle orbits during double {\beta} decay in 100Mo
The rearrangements of protons and neutrons amongst the valence
single-particle orbitals during double {\beta} decay of 100Mo have been
determined by measuring cross sections in (d,p), (p,d), (3He,{\alpha}) and
(3He,d) reactions on 98,100Mo and 100,102Ru targets. The deduced nucleon
occupancies reveal significant discrepancies when compared with theoretical
calculations; the same calculations have previously been used to determine the
nuclear matrix element associated with the decay probability of double {\beta}
decay of the 100Mo system.Comment: 18 pages, 13 figures, 37 pages of supplemental informatio
Effects of Incorporation of Sainfoin (\u3ci\u3eOnobrychis viciafolia\u3c/i\u3e Scop.) with Cool Season Grasses on \u3ci\u3ein vitro\u3c/i\u3e Digestibility and CH4 Emission
Sainfoin (Onobrychis viciafolia Scop.) is an important non-bloating perennial leguminous forage. The tannins in sainfoin alter protein metabolism in the rumen and have been implicated in altering both nitrous oxide and methane emissions. However, the effect of sainfoin when mixed with cool-season forages is unknown. Therefore, in this study, we evaluated the in-vitro fermentation of sainfoin hay mixed with two other perennial cool-season forages, meadow bromegrass and orchardgrass at five ratios (0:100, 25:75, 50:50, 75:50, and 100:0). Data on dry matter disappearance (DMD), neutral detergent fiber disappearance (NDFD), gas production (GP) methane (CH4) emissions, and ammonia production were collected 48 h post incubation. Ruminal fluid was sourced from three heifers fed with forage hay. Incubations were conducted with and without PEG (polyethylene glycol) as PEG negates the biological activity of tannins. Sainfoin had a higher nutritive value than the other two grass species as evidenced by the higher proportion of total nitrogen and lower proportion of ADF and NDF. The change in DMD, ammonia-N, NDFD, GP, and CH4 emissions between sainfoin and grass only hay were 3.1, 9.2, -36.8, -1.76, and -1.2% respectively with the intermediate results for the mixture. The inclusion of sainfoin with cool-season grasses has positive effects on ruminal fermentation and lowered in vitro methane emissions as compared to grass alon
The Relationship of Coronal Mass Ejections to Streamers
We have examined images from the Large Angle Spectroscopic Coronagraph
(LASCO) to study the relationship of Coronal Mass Ejections (CMEs) to coronal
streamers. We wish to test the suggestion (Low 1996) that CMEs arise from flux
ropes embedded in a streamer erupting, thus disrupting the streamer. The data
span a period of two years near sunspot minimum through a period of increased
activity as sunspot numbers increased. We have used LASCO data from the C2
coronagraph which records Thomson scattered white light from coronal electrons
at heights between 1.5 and 6R_sun. Maps of the coronal streamers have been
constructed from LASCO C2 observations at a height of 2.5R_sun at the east and
west limbs. We have superposed the corresponding positions of CMEs observed
with the C2 coronagraph onto the synoptic maps. We identified the different
kinds of signatures CMEs leave on the streamer structure at this height
(2.5R_sun). We find four types of CMEs with respect to their effect on
streamers:
1. CMEs that disrupt the streamer 2. CMEs that have no effect on the
streamer, even though they are related to it. 3. CMEs that create streamer-like
structures 4. CMEs that are latitudinally displaced from the streamer.
This is the most extensive observational study of the relation between CMEs
and streamers to date. Previous studies using SMM data have made the general
statement that CMEs are mostly associated with streamers, and that they
frequently disrupt it. However, we find that approximately 35% of the observed
CMEs bear no relation to the pre-existing streamer, while 46% have no effect on
the observed streamer, even though they appear to be related to it. Our
conclusions thus differ considerably from those of previous studies.Comment: Accepted, Journal of Geophysical Research. 8 figs, better versions at
http://www.science.gmu.edu/~prasads/streamer.htm
Chasing Brane Inflation in String-Theory
We investigate the embedding of brane anti-brane inflation into a concrete
type IIB string theory compactification with all moduli fixed. Specifically, we
are considering a D3-brane, whose position represents the inflaton , in a
warped conifold throat in the presence of supersymmetrically embedded D7-branes
and an anti D3-brane localized at the tip of the warped conifold cone. After
presenting the moduli stabilization analysis for a general D7-brane embedding,
we concentrate on two explicit models, the Ouyang and the Kuperstein
embeddings. We analyze whether the forces, induced by moduli stabilization and
acting on the D3-brane, might cancel by fine-tuning such as to leave us with
the original Coulomb attraction of the anti D3-brane as the driving force for
inflation. For a large class of D7-brane embeddings we obtain a negative
result. Cancelations are possible only for very small intervals of
around an inflection point but not globally. For the most part of its motion
the inflaton then feels a steep, non slow-roll potential. We study the
inflationary dynamics induced by this potential.Comment: 34 pages, 4 figures. Final version published in JCA
Reconstructing a model of quintessential inflation
We present an explicit cosmological model where inflation and dark energy
both could arise from the dynamics of the same scalar field. We present our
discussion in the framework where the inflaton field attains a nearly
constant velocity (where
is the e-folding time) during inflation. We show that the model
with and can easily satisfy inflationary constraints,
including the spectral index of scalar fluctuations (),
tensor-to-scalar ratio () and also the bound imposed on
during the nucleosynthesis epoch (). In our
construction, the scalar field potential always scales proportionally to the
square of the Hubble expansion rate. One may thereby account for the two vastly
different energy scales associated with the Hubble parameters at early and late
epochs. The inflaton energy could also produce an observationally significant
effective dark energy at a late epoch without violating local gravity tests.Comment: 18 pages, 7 figures; added refs, published versio
Challenges for String Cosmology
We critically assess the twin prospects of describing the observed universe
in string theory, and using cosmological experiments to probe string theory.
For the purposes of this short review, we focus on the limitations imposed by
our incomplete understanding of string theory. After presenting an array of
significant obstacles, we indicate a few areas that may admit theoretical
progress in the near future.Comment: 18 pages; contribution to a focus issue on string cosmology for
Classical and Quantum Gravit
Washington Legislation—1941 (Continued)
The survey of selected important enactments of the Twenty-Seventh Legislature of the State of Washington, first installment of which appeared in the April issue of the REVww, is continued and concluded in this issue
Oscillations in the bispectrum
There exist several models of inflation that produce primordial bispectra
that contain a large number of oscillations. In this paper we discuss these
models, and aim at finding a method of detecting such bispectra in the data. We
explain how the recently proposed method of mode expansion of bispectra might
be able to reconstruct these spectra from separable basis functions. Extracting
these basis functions from the data might then lead to observational
constraints on these models.Comment: 6 pages, 2 figures, submitted to JOP: Conference Series, PASCOS 201
- …