1,358 research outputs found
Cosmic Electroweak Strings
We examine the Standard Model field configurations near cosmic strings in a
particular class of models. This class is defined by the condition that the
generator of the flux in the string, , commutes with the Standard Model
Lie algebra. We find that if the Standard Model Higgs carries a charge
under , cosmic string solutions have Z-flux , where is any integer and is the flux of the gauge field associated with . Only the
configuration with the smallest value of is stable,
however. We argue that the instabilities found at higher are just
associated with paths in configuration space reducing by
one unit. This contradicts recent claims that the instabilities in such models
represent the spontaneous generation of current along the string. We also show
that the stable strings have no Standard Model fermion zero modes: therefore
there is no possibility of supercurrents carried by Standard Model particles in
this class of models.Comment: Latex, 13 pages, 2 uuencoded figure
Instabilities of Electroweak Strings
We investigate the instabilities of low winding number electroweak strings
using standard numerical techniques of linear algebra. For strings of unit
winding we are able to confirm and extend existing calculations of the unstable
region in the () plane. For strings of higher winding
number we map the unstable regions for the various decay modes.Comment: Latex, 11 pages, 1 uuencoded figur
Evaluation of barley for finishing swine
Three-hundred and ten crossbred finishing pigs averaging 110 lbs. were utilized in two growth trials to evaluate the effects of feeding barley to finishing hogs. In both experiments, there were no differences in average daily gain or average daily feed intake between hogs fed the milo-soybean meal control diet, a pelleted barley diet, or a 5% added fat barley diet. However, there was a significant decrease in average daily gain with the basal barley diet and a barley diet balanced on a lysine basis. Pelleting or adding fat significantly improved feed efficiency. In Experiment 2, hogs fed a 5% molasses diet and a rolled barley diet had the lowest average daily gains and poorest feed efficiency. These results indicate that pelleting and adding fat to barley-based diets improve average daily gain and feed efficiency. It would also appear that diets with barley substituted lb. for lb. for milo or balanced on a lysine basis have approximately 90-95% the value of a milo-soybean meal diet for finishing swine.; Swine Day, Manhattan, KS, November 21, 198
The effects of medium-oil dried distillers grains with solubles on growth performance and carcass traits in finishing pigs
An experiment was conducted to determine the effects of increasing medium-oil dried
distillers grains with solubles (DDGS; 7.4% fat, 28.1% CP, 10.8% ADF, and 25.6%
NDF) on growth performance and carcass traits in finishing pigs. A total of 288 pigs
(PIC 327 × 1050; initially 151.8 lb) were allotted to 1 of 4 dietary treatments. Treatments
consisted of a corn-soybean meal control diet or the control diet with 15, 30, or
45% medium-oil DDGS, with 8 pigs per pen and 8 replications per treatment. Increasing
medium-oil DDGS decreased (linear, P < 0.01) ADG and worsened (linear,
P < 0.02) F/G. In addition, final BW, HCW, carcass yield, and loin-eye depth
decreased (linear, P < 0.03), and jowl iodine value (IV) increased (linear, P < 0.001)
with increasing medium-oil DDGS. When pigs are fed traditional DDGS containing
>10.5% fat, each 10% DDGS added to the diet increases jowl IV approximately 2 mg/g;
however, feeding increasing medium-oil DDGS increased jowl IV only about 1.4 units
per each 10% DDGS. In conclusion, swine producers must be aware of the negative
ramifications on growth performance of using medium-oil DDGS in swine diets
Effects of added Zn in diets with Ractopamine HCl on growth performance and carcass quality of finishing pigs in a commercial environment
The experiment was conducted in a commercial facility to determine the effects of added Zn on the performance of finishing pigs fed Ractopamine HCl (RAC; Paylean®; Elanco Animal Health, Greenfield, IN). Pigs were randomly assigned to pens based on gender (14 barrow pens, 11 gilt pens, and 23 mixed-gender pens), with 25 to 28 pigs per pen. Previously, pens of pigs were assigned to treatments containing 0, 7.5, or 15% bakery by-product in a completely randomized design while balancing for initial BW and gender. On d 75, treatments were implemented to determine the effects of adding 50 ppm Zn from ZnO on finishing pig performance. A total of 1,234 pigs (PIC 337 × 1050; average BW 224.6 lb) were used in a 28-d study. Pens of pigs were randomly assigned to diets with and without 50 ppm added Zn from zinc oxide (ZnO) and balanced by BW, bakery by-product, and gender. All diets contained 5 ppm RAC and 83 ppm Zn from ZnO provided by the trace mineral premix. There were 24 pens per treatment.
Overall (d 75 to 102), no differences (P > 0.22) in growth performance or carcass characteristics were observed when pigs were fed diets with 50 ppm added Zn compared with the RAC control. For pigs subsampled on d 84, pigs fed diets with 50 ppm added Zn had decreased (P < 0.05) edge belly thickness compared with pigs fed the control. For pigs subsampled on d 102, pigs fed diets with 50 ppm added Zn had decreased
(P < 0.02) backfat thickness, belly weight, and edge belly thickness; a tendency for decreased (P < 0.07) middle belly thickness; and increased (P < 0.01) percentage lean compared with pigs fed the RAC control. In contrast with our previous research, these data indicate that adding 50 ppm Zn from ZnO to finishing pig diets containing RAC did not improve overall performance. Consistent with the earlier research, income over feed cost (IOFC) was numerically increased with the addition of Zn
The interactive effects of high-fiber diets and Ractopamine HCl on finishing pig growth performance, carcass characteristics, carcass fat quality, and intestinal weights
In previous research, feeding pigs high amounts of dried distillers grains with solubles
(DDGS) and wheat middlings (midds) has been shown to reduce carcass yield and
negatively affect iodine value (IV). The influence of Ractopamine HCl (RAC; Paylean,
Elanco Animal Health, Greenfield, IN) on this response is not known; therefore, a total
of 575 finishing pigs (PIC 327 × 1050, initially 123 lb) were used in two consecutive
73-d trials to determine the effects of DDGS and midds (high fiber) withdrawal 24
d before harvest in diets with or without RAC on finishing pig growth performance,
carcass characteristics, and fat quality. From d 0 to 49, pigs were allotted to 1 of 2
dietary treatments in a completely randomized design based on initial pen weight. The
dietary treatments included a corn-soybean meal–based control diet or diets with 30%
DDGS and 19% wheat midds. Twelve pens of pigs were fed the corn-soybean meal
control diet, and 24 pens were fed the high-fiber diet. During this 49 d period, pigs fed
the corn-soybean meal diets had improved (P < 0.0001) ADG and F/G compared with
those fed the high-fiber diets.
On d 49, pens of pigs were re-allotted to 1 of 6 dietary treatments; pigs remained on
the corn-soybean meal diets, switched from the high-fiber diet to corn-soybean meal
(withdrawal diet), or were maintained on the high-fiber diet. These 3 regimens were fed
with or without 9 g/ton RAC
Stability Analysis of Superconducting Electroweak Vortices
We carry out a detailed stability analysis of the superconducting vortex
solutions in the Weinberg-Salam theory described in Nucl.Phys. B826 (2010) 174.
These vortices are characterized by constant electric current and electric
charge density , for they reduce to Z strings. We consider the
generic field fluctuations around the vortex and apply the functional Jacobi
criterion to detect the negative modes in the fluctuation operator spectrum. We
find such modes and determine their dispersion relation, they turn out to be of
two different types, according to their spatial behavior. There are
non-periodic in space negative modes, which can contribute to the instability
of infinitely long vortices, but they can be eliminated by imposing the
periodic boundary conditions along the vortex. There are also periodic negative
modes, but their wavelength is always larger than a certain minimal value, so
that they cannot be accommodated by the short vortex segments. However, even
for the latter there remains one negative mode responsible for the homogeneous
expansion instability. This mode may probably be eliminated when the vortex
segment is bent into a loop. This suggests that small vortex loops balanced
against contraction by the centrifugal force could perhaps be stable.Comment: 42 pages, 11 figure
Generic Current-Carrying Strings
We investigate the standard model in a cosmic string background and show that
the electroweak symmetry is partially restored. For a range of parameters the
electroweak Higgs field can wind in this region, producing an electroweak
string stabilised by the cosmic string background. In this case there are quark
and lepton zero modes that result in the string becoming superconducting at the
electroweak scale. If the electroweak Higgs field does not wind, there are no
zero modes, but there are fermion bound states. These bound states can also
carry a current.Comment: 8 pages, TeX, 5 postscript figure
- …