38,060 research outputs found

    Survey of J=0,1 mesons in a Bethe-Salpeter approach

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    The Bethe-Salpeter equation is used to comprehensively study mesons with J=0,1 and equal-mass constituents for quark masses from the chiral limit to the b-quark mass. The survey contains masses of the ground states in all corresponding J^{PC} channels including those with "exotic" quantum numbers. The emphasis is put on each particular state's sensitivity to the low- and intermediate-momentum, i.e., long-range part of the strong interaction.Comment: 8 pages, 4 figure

    Expression of PTHrP and PTHR (PTH/PTHrP-r) mRNAs and polypeptides in bovine ovary and stimulation of bovine blastocyst development in vitro following PTHrP treatment during oocyte maturation.

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    Parathyroid hormone related protein (PTHrP) and its receptor have well-established roles in the development and regulation of many tissues, including bone and mammary gland. The objectives of this study were: (1) to characterize the distribution of mRNAs encoding parathyroid hormone (PTH)-related protein (PTHrP) and receptor (PTHR) in bovine ovary; (2) to characterize the distribution of PTHrP and PTHR polypeptides in bovine ovary; (3) to examine the influences of PTHrP (1-141) treatment during bovine oocyte maturation in vitro on blastocyst development. mRNAs encoding PTHrP and PTHR were detected by in situ hybridization methods in oocytes, and granulosa cells in all follicles from primordial to large antral. PTHrP and PTHR polypeptides displayed distinct distribution patterns with PTHrP polypeptides primarily confined to oocytes from primordial to large antral follicles. PTHrP polypeptides were detectable but at a reduced level in ovarian stroma and in granulosa and thecal layers. PTHR polypeptides were detected in oocytes of all follicular stages but were predominantly found in ovarian stroma, granulosa and theca follicular layers. Supplementation of serum-free cSOFMaa oocyte maturation medium with PTHrP (1-141) resulted in a concentration-dependent increase in development to the blastocyst stage in vitro. The results suggest that granulosa cells may be a primary site of PTHrP production and release. Oocytes from all follicular stages stained strongly for PTHrP polypeptides and PTHrP enhanced development to the blastocyst stage in vitro

    Estimating the masses of extra-solar planets

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    All extra-solar planet masses that have been derived spectroscopically are lower limits since the inclination of the orbit to our line-of-sight is unknown except for transiting systems. It is, however, possible to determine the inclination angle, i, between the rotation axis of a star and an observer's line-of-sight from measurements of the projected equatorial velocity (v sin i), the stellar rotation period (P_rot) and the stellar radius (R_star). This allows the removal of the sin i dependency of spectroscopically derived extra-solar planet masses under the assumption that the planetary orbits lie perpendicular to the stellar rotation axis. We have carried out an extensive literature search and present a catalogue of v sin i, P_rot, and R_star estimates for exoplanet host stars. In addition, we have used Hipparcos parallaxes and the Barnes-Evans relationship to further supplement the R_star estimates obtained from the literature. Using this catalogue, we have obtained sin i estimates using a Markov-chain Monte Carlo analysis. This allows proper 1-sigma two-tailed confidence limits to be placed on the derived sin i's along with the transit probability for each planet to be determined. While a small proportion of systems yield sin i's significantly greater than 1, most likely due to poor P_rot estimations, the large majority are acceptable. We are further encouraged by the cases where we have data on transiting systems, as the technique indicates inclinations of ~90 degrees and high transit probabilities. In total, we estimate the true masses of 133 extra-solar planets. Of these, only 6 have revised masses that place them above the 13 Jupiter mass deuterium burning limit. Our work reveals a population of high-mass planets with low eccentricities and we speculate that these may represent the signature of different planetary formation mechanisms at work.Comment: 40 pages, 6 tables, 2 figures. Accepted for publication in the Monthly Notices of the Royal Astronomical Society after editing of Tables 1 & 6 for electronic publication. Html abstract shortened for astro-ph submissio

    Evaluating the impact of selected cases under the Human Rights Act on public services provision

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    The report explores the impact of the outcome of a number of strategic human rights legal cases on a range of public authorities in England and Wales

    Dynamical decompactification from brane gases in eleven-dimensional supergravity

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    Brane gas cosmology provides a dynamical decompactification mechanism that could account for the number of spacetime dimensions we observe today. In this work we discuss this scenario taking into account the full bosonic sector of eleven-dimensional supergravity. We find new cosmological solutions that can dynamically explain the existence of three large spatial dimensions characterised by an universal asymptotic scaling behaviour and a large number of initially unwrapped dimensions. This type of solutions enlarge the possible initial conditions of the Universe in the Hagedorn phase and consequently can potentially increase the probability of dynamical decompactification from anisotropically wrapped backgrounds.Comment: 8 figures, JHEP3 styl

    The Distance to the Large Magellanic Cloud from the Eclipsing Binary HV2274

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    The distance to the Large Magellanic Cloud (LMC) is crucial for the calibration of the Cosmic Distance Scale. We derive a distance to the LMC based on an analysis of ground-based photometry and HST-based spectroscopy and spectrophotometry of the LMC eclipsing binary system HV2274. Analysis of the optical light curve and HST/GHRS radial velocity curve provides the masses and radii of the binary components. Analysis of the HST/FOS UV/optical spectrophotometry provides the temperatures of the component stars and the interstellar extinction of the system. When combined, these data yield a distance to the binary system. After correcting for the location of HV2274 with respect to the center of the LMC, we find d(LMC) = 45.7 +/- 1.6 kpc or DM(LMC) = 18.30 +/- 0.07 mag. This result, which is immune to the metallicity-induced zero point uncertainties that have plagued other techniques, lends strong support to the ``short'' LMC distance scale as derived from a number of independent methods.Comment: 6 pages, including 2 pages of figures. Newly available optical (B and V) photometry has revealed -- and allowed the elimination of -- a systematic error in the previously reported determination of E(B-V) for HV2274. The new result is E(B-V) = 0.12 mag (as compared to the value of 0.083 reported in the original submission) and produces a DECREASE in the distance modulus of HV2274 by 0.12 mag. ApJ Letters, in pres

    Defining the gap between research and practice in public relations programme evaluation - towards a new research agenda

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    The current situation in public relations programme evaluation is neatly summarized by McCoy who commented that 'probably the most common buzzwords in public relations in the last ten years have been evaluation and accountability' (McCoy 2005, 3). This paper examines the academic and practitioner-based literature and research on programme evaluation and it detects different priorities and approaches that may partly explain why the debate on acceptable and agreed evaluation methods continues. It analyses those differences and proposes a research agenda to bridge the gap and move the debate forward

    Investigation of flow fields within large scale hypersonic inlet models

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    Analytical and experimental investigations were conducted to determine the internal flow characteristics in model passages representative of hypersonic inlets for use at Mach numbers to about 12. The passages were large enough to permit measurements to be made in both the core flow and boundary layers. The analytical techniques for designing the internal contours and predicting the internal flow-field development accounted for coupling between the boundary layers and inviscid flow fields by means of a displacement-thickness correction. Three large-scale inlet models, each having a different internal compression ratio, were designed to provide high internal performance with an approximately uniform static-pressure distribution at the throat station. The models were tested in the Ames 3.5-Foot Hypersonic Wind Tunnel at a nominal free-stream Mach number of 7.4 and a unit free-stream Reynolds number of 8.86 X one million per meter
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