4,445 research outputs found

    Rotation periods of exoplanet host stars

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    The stellar rotation periods of ten exoplanet host stars have been determined using newly analysed Ca II H & K flux records from Mount Wilson Observatory and Stromgren b, y photometric measurements from Tennessee State University's automatic photometric telescopes (APTs) at Fairborn Observatory. Five of the rotation periods have not previously been reported, with that of HD 130322 very strongly detected at Prot = 26.1 \pm 3.5 d. The rotation periods of five other stars have been updated using new data. We use the rotation periods to derive the line-of-sight inclinations of the stellar rotation axes, which may be used to probe theories of planet formation and evolution when combined with the planetary orbital inclination found from other methods. Finally, we estimate the masses of fourteen exoplanets under the assumption that the stellar rotation axis is aligned with the orbital axis. We calculate the mass of HD 92788 b (28 MJ) to be within the low-mass brown dwarf regime and suggest that this object warrants further investigation to confirm its true nature.Comment: Accepted for publication in MNRAS. 15 pages, 11 figure

    Effect of Backgrounding System on Performance and Profitability of Yearling Beef Steers

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    Five summer management strategies were compared following grazing corn residue through winter. Cattle were assigned to be 1) summer finished, 2) graze bromegrass, 3) graze bromegrass and fed distillers grains at 0.6% of BW, 4) backgrounded in a drylot pen to gain 1.70 lb/d, or 5) backgrounded in a drylot pen to gain 2.35 lb/d. Results differed by year, however, in general as backgrounding ADG increased, days required on feed to reach an equal fat endpoint decreased. In year 1, ADG of cattle grazing bromegrass was less than cattle backgrounded in pens. There was no difference in finishing ADG for summer backgrounded steers. In year 2, steers grazing bromegrass with no supplement had the lowest summer ADG but exhibited compensatory growth in the feedlot. Overall, backgrounding systems increase carcass weights when cattle are finished to an equal fat thickness

    Effect of Increasing Supplemental Rumen Undegradable Protein (RUP) on Performance of Calves Fed a Silage Growing Diet

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    A growing study evaluated the effects of increasing supplemental rumen undegradable protein (RUP) on performance of calves fed an 85% corn silage diet. Five levels of supplementation were evaluated with 12 individually fed steers per level of supplement. Supplement levels consisted of 0, 3.25, 6.5, 9.75 and 13% supplemental RUP (% of diet DM) fed as a blend of 60% Soypass and 40% Empyreal. Increasing supplemental RUP in the diet increased ending body weight and average daily gain linearly, and decreased F:G linearly while DMI remained constant among treatments. As cattle grew from 600 to 730 lb, F:G was improved 30% by supplying RUP. Th e same amount of RUP improved F:G by 11% as cattle grew beyond 730 lb. By meeting MP requirements, supplementing RUP linearly improved both ADG and F:G of growing calves, especially early in the growing period

    Effect of Increasing Supplemental Rumen Undegradable Protein (RUP) on Performance of Calves Fed a Silage Growing Diet

    Get PDF
    A growing study evaluated the effects of increasing supplemental rumen undegradable protein (RUP) on performance of calves fed an 85% corn silage diet. Five levels of supplementation were evaluated with 12 individually fed steers per level of supplement. Supplement levels consisted of 0, 3.25, 6.5, 9.75 and 13% supplemental RUP (% of diet DM) fed as a blend of 60% Soypass and 40% Empyreal. Increasing supplemental RUP in the diet increased ending body weight and average daily gain linearly, and decreased F:G linearly while DMI remained constant among treatments. As cattle grew from 600 to 730 lb, F:G was improved 30% by supplying RUP. Th e same amount of RUP improved F:G by 11% as cattle grew beyond 730 lb. By meeting MP requirements, supplementing RUP linearly improved both ADG and F:G of growing calves, especially early in the growing period

    Effect of Continuous or Rotational Grazing on Growing Steer Performance and Land Production

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    Individual animal performance and animal production per acre were evaluated for steers grazing smooth bromegrass over 2 consecutive years. Treatments consisted of steers continuously grazing smooth bromegrass and initially stocked at either 4.0 animal unit months (AUM)/ac (HI) or 2.8 AUM/ac (LO) or steers rotationally grazing smooth bromegrass and initially stocked at 4.0 AUM/ac (ROT). Average calculated stocking rate for the LO, HI, and ROT treatments was greater than initial stocking rates due to the use of put and take animals. In vitro organic matter digestibility and crude protein of rotationally grazed pastures was relatively constant as the grazing season progressed, whereas continuous grazing showed a decrease in digestibility. However, there were no differences in gain between treatments. Treatment pastures grazed at a higher intensity, regardless of grazing method, had greater calculated stocking rate than pastures grazed at a lower intensity. Gain per acre, however, did not differ among treatments. Overall, although there was an increase in diet sample quality associated with rotational grazing compared to continuously grazed pastures, greater emphasis should likely be placed on managing an appropriate grazing intensity, rather than grazing method

    Multi-field Inflation with a Random Potential

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    Motivated by the possibility of inflation in the cosmic landscape, which may be approximated by a complicated potential, we study the density perturbations in multi-field inflation with a random potential. The random potential causes the inflaton to undergo a Brownian motion with a drift in the D-dimensional field space. To quantify such an effect, we employ a stochastic approach to evaluate the two-point and three-point functions of primordial perturbations. We find that in the weakly random scenario the resulting power spectrum resembles that of the single field slow-roll case, with up to 2% more red tilt. The strongly random scenario, leads to rich phenomenologies, such as primordial fluctuations in the power spectrum on all angular scales. Such features may already be hiding in the error bars of observed CMB TT (as well as TE and EE) power spectrum and can be detected or falsified with more data coming in the future. The tensor power spectrum itself is free of fluctuations and the tensor to scalar ratio is enhanced. In addition a large negative running of the power spectral index is possible. Non-Gaussianity is generically suppressed by the growth of adiabatic perturbations on super-horizon scales, but can possibly be enhanced by resonant effects or arise from the entropic perturbations during the onset of (p)reheating. The formalism developed in this paper can be applied to a wide class of multi-field inflation models including, e.g. the N-flation scenario.Comment: More clarifications and references adde

    Multi-field Inflation with a Random Potential

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    Motivated by the possibility of inflation in the cosmic landscape, which may be approximated by a complicated potential, we study the density perturbations in multi-field inflation with a random potential. The random potential causes the inflaton to undergo a Brownian motion with a drift in the D-dimensional field space. To quantify such an effect, we employ a stochastic approach to evaluate the two-point and three-point functions of primordial perturbations. We find that in the weakly random scenario the resulting power spectrum resembles that of the single field slow-roll case, with up to 2% more red tilt. The strongly random scenario, leads to rich phenomenologies, such as primordial fluctuations in the power spectrum on all angular scales. Such features may already be hiding in the error bars of observed CMB TT (as well as TE and EE) power spectrum and can be detected or falsified with more data coming in the future. The tensor power spectrum itself is free of fluctuations and the tensor to scalar ratio is enhanced. In addition a large negative running of the power spectral index is possible. Non-Gaussianity is generically suppressed by the growth of adiabatic perturbations on super-horizon scales, but can possibly be enhanced by resonant effects or arise from the entropic perturbations during the onset of (p)reheating. The formalism developed in this paper can be applied to a wide class of multi-field inflation models including, e.g. the N-flation scenario.Comment: More clarifications and references adde

    The XMM–NEWTON ℩ Project: I. The X-ray luminosity – temperature relation at z>0.4

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    We describe XMM-Newton Guaranteed Time observations of a sample of eight high redshift (0.45 < z < rvirial) bolometric luminosities, performed ÎČ-model fits to the radial surface profiles and made spectral fits to a single temperature isothermal model. We describe data analysis techniques that pay particular attention to background mitigation. We have also estimated temperatures and luminosities for two known clusters (Abell 2246 and RXJ1325.0-3814), and one new high redshift cluste r candidate (XMMU J084701.8 +345117), that were detected o ff-axis. Characterizing the L x − Tx relation as L x = L 6 ( T 6keV ) α , we find L 6 = 15 . 9 + 7 . 6 − 5 . 2 × 1044erg s − 1 and α =2.7 ±0.4 for an ℩ Λ = 0 . 0 , ℩ M = 1 .0, H0 = 50 km s − 1 Mpc − 1 cosmology at a typical redshift z ∌ 0 .55. Comparing with the low redshift study by Markevitch, 1998, we find α to be in agreement, and assuming L x − Tx to evolve as (1 + z ) A , we find A =0.68 ±0.26 for the same cosmology and A = 1 .52 + 0 .26 − 0 .27 for an ℩ Λ = 0 . 7 , ℩ M = 0 . 3 cosmology. Our A values are very similar to those found previously by Vikhlinin et al., 2002 using a compilation of Chandra observations of 0 .39 < z < 1 .26 clusters. We conclude that there is now evidence from both XMM-Newton and Chandra for an evolutionary trend in the L x − Tx relation. This evolution is significantly below the level expected from the predictions of the self-similar model for an ℩ Λ = 0 . 0 , ℩ M = 1 .0, cosmology, but consistent with self-similar model in an ℩ Λ = 0 . 7 , ℩ M = 0 . 3 cosmology. Our observations lend support to the robustness and completeness of the SHARC and 160SD surveys

    Fibrinogenolysis and fibrinolysis in Vaccine-induced Immune Thrombocytopenia and Thrombosis (VITT)

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    Acknowledgements The authors would like to thank all the patients whose samples were used as part of this study, and all the NHS Scotland staff who collected patient samples and looked after these patients. We thank Aberdeen Royal Infirmary Haematology laboratory for conducting the anti-platelet factor 4 antibody testing and Dr Sue Pavord, Consultant Haematologist at Oxford Teaching Hospitals for help in gathering clinical data on the patients. Funding This research was supported by The University of Aberdeen Development Trust (RG16009). CSW and NJM are supported by the British Heart Foundation (PG/15/82/31721; PG/20/17/35050).Peer reviewedPublisher PD
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