769 research outputs found

    Cosmic Electroweak Strings

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    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, TsT_s, commutes with the Standard Model Lie algebra. We find that if the Standard Model Higgs carries a charge Fh/2F_h /2 under TsT_s, cosmic string solutions have Z-flux ΦZ=[nFhN/Fϕ]4πcosθw/g\Phi_Z =[n-F_h N/F_{\phi}]4\pi \cos \theta_w /g, where nn is any integer and 4πN/qFϕ4\pi N/qF_{\phi} is the flux of the gauge field associated with TsT_s. Only the configuration with the smallest value of nFhN/Fϕ|n-F_h N/F_{\phi}| is stable, however. We argue that the instabilities found at higher ΦZ\Phi_Z are just associated with paths in configuration space reducing nFhN/Fϕ|n-F_h N/F_{\phi}| 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

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    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 (mH/mW,sin2θWm_H/m_W,\sin^2\theta_W) plane. For strings of higher winding number we map the unstable regions for the various decay modes.Comment: Latex, 11 pages, 1 uuencoded figur

    Summary of Kansas State University swine enterprise record 1997

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    The Kansas Swine Enterprise Record Program evaluates biological and economic performance and is part of a cooperative record- keeping project with Extension personnel and swine producers in Kansas. Nebraska, and South Dakota. From January 1 to December 31, 1996, profit per cwt of pork produced by these producers (13 semiannual and 18 annual data) averaged 10.62forthelast6monthsof1996and10.62 for the last 6 months of 1996 and 8.08 for the entire year. Producers in the top one-third in terms of profitability had average profits of 15.11percwt,whereasproducersinthebottomonethirdhadaverageprofitsof15.11 per cwt, whereas producers in the bottom one-third had average profits of .73 per cwt for the year. Critical factors separating low- and high-profit producers included feed costs, unpaid labor, fixed costs, and death loss.; Swine Day, Manhattan, KS, November 20, 199

    The effects of medium-oil dried distillers grains with solubles on growth performance and carcass traits in finishing pigs

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    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

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    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

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    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

    In vitro branched chain amino acid oxidation by porcine mammary tissue

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    Mammary secretory tissue from six (three each of parity 1 and 2) lactating sows (d 10 to 17 of lactation) was obtained via biopsy for in vitro incubation to determine CO2 production fr01TI individual branched chain amino acids. Carbon dioxide production levels as percentages of the 14C-labeled amino acid metabolized by the mammary tissue were 2.57, 1.86, and 4.07% for isoleucine, leucine, and valine, respectively (P\u3c .03). These results indicate that, in the lactating sow mammary gland, valine has the greatest oxidation rate of the branched chain amino acids.; Swine Day, Manhattan, KS, November 16, 199

    The effects of BMD in lactation diets on sow and litter performance

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    One hundred forty-five multiparous sows were used in a performance trial to evaluate the use of BMD® (bacitracin methylene disalicylate) on sow and litter performance during lactation in a herd with no previously documented history of Clostridium perfringens type C or D. Between day 96 and 100 of gestation, sows were allotted to one of two dietary treatments, either a diet containing 250 g/ton of BMD or the control diet with no antibiotic. Sows were fed the experimental diets until weaning (approx. 20 d). Litters were equalized to approximately 10 pigs per sow within 48 hrs postfarrowing. Piglets were transferred only within treatment. Piglets on sows fed the BMD treatment had a reduced incidence of diarrhea (P=.10); however, the antibiotic had no effect on sow or litter performance.; Swine Day, Manhattan, KS, November 18,199

    Using mixer efficiency testing to evaluate feed segregation in feed lines

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    An experiment was conducted to evaluate potential diet segregation in feed lines by measuring coefficient of variation (CV) and mean salt concentration. The facility was a 1500-head gestation barn with nine feed lines, transected by a central feed line that conveyed feed from one of two bulk bins. Quantab® chloride titrators were used to analyze the chloride concentration (salt) from samples collected at pre-determined feed line locations at various distances from the bulk bins. Thirty samples were collected from three feed lines (row 1, 5, and 9), ten samples were collected from drop boxes close to the central feed line (location 1), ten samples were collected from a central location within the row (location 2), and ten samples were collected from the furthest end of the feed line (location 3). Samples of approximately 50 g were collected directly from the feed drop. The sample collection procedure was repeated four times. After the first two sample collections, a bin agitator was added to the bulk bin. There was a feed line × distance (within the feed line) × agitator interaction (P > 0.02) observed for CV. The addition of the bin agitator improved the CV in feed line 1 and 5, with no improvement observed in feed line 9. The CV observed before the addition of the agitator averaged 17.6, 18.6, and 14.3% for feed lines 1, 5, and 9, respectively, and the CV observed after the addition of the agitator averaged 13.6, 16, and 14% for feed line 1, 5, and 9 respectively. Within all feed lines (rows), distance CV was higher at locations 1 (17.3%) and 3 (17.6%), compared with CV at location 2 (15.6%) before the addition of the agitator, but was lower at locations 1 (14.3%) and 3 (13.0%), compared with CV at location 2 (15.6%) after the addition of the agitator. There was a mean-salt concentration effect (P<0.0001) observed for feed line. Feed lines 1 and 5 were similar in mean salt concentration, whereas feed line 9 consistently had the highest salt concentration. There was little to no feed segregation observed
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