251 research outputs found

    Root Caries in an Optimally Fluoridated and a High-fluoride Community

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    The purpose of this study was to measure the prevalence and distribution of root caries in two New Mexico communities. One community, Deming, had a natural fluoride concentration of 0.7 mglL in its drinking water, optimum for its climate. The other, Lordsburg, was naturally fluoridated at 3.5 mg/L, five times the optimum. Dental examinations were carried out on 151 adults in Deming (mean age, 39.8 years) and 164 in Lordsburg (mean age, 43.2 years); only persons born in the communities were included. Prevalence of root caries was 23.8% in Deming and 7.3% in Lordsburg; mean number of lesions was 0.69 in Deming and 0.08 in Lordsburg (p < 0.0001). Although there was more gingival recession in Lordsburg, Root Caries Index scores were five times greater in Deming. Root caries was more prevalent in older age groups, and was correlated with coronal caries experience in both communities. Root caries was correlated with plaque and calculus scores in Deming only. Logistic regression showed that city of residence was the major predictor of root caries, with other significant predictors being age, education, gingival recession, and loss of periodontal attachment. When combined with previous research, these results confirm that root caries experience is directly related to the fluoride concentration in the drinking water.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66733/2/10.1177_00220345860650090801.pd

    Seesaw Extended MSSM and Anomaly Mediation without Tachyonic Sleptons

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    Superconformal anomalies provide an elegant and economical way to understand the soft breaking parameters in SUSY models; however, implementing them leads to the several undesirable features including: tachyonic sleptons and electroweak symmetry breaking problems in both the MSSM and the NMSSM. Since these two theories also have the additonal problem of massless neutrinos, we have reconsidered the AMSB problems in a class of models that extends the NMSSM to explain small neutrino masses via the seesaw mechanism. In a recent paper, we showed that for a class of minimal left-right extensions, a built-in mechanism exists which naturally solves the tachyonic slepton problem and provides new alternatives to the MSSM that also have automatic R-parity conservation. In this paper, we discuss how electroweak symmetry breaking arises in this model through an NMSSM-like low energy theory with a singlet VEV, induced by the structure of the left-right extension and of the right magnitude. We then study the phenomenological issues and find: the LSP is an Higgsino-wino mix, new phenomenology for chargino decays to the LSP, degenerate same generation sleptons and a potential for a mild squark-slepton degeneracy. We also discuss possible collider signatures and the feasibility of dark matter in this model.Comment: 40 pages, 10 figures, 5 tables; v3: Added addendum and three new references; v4: Added reference that was inadvertently omitte

    A genomic prediction model for racecourse starts in the Thoroughbred horse

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    Durability traits in Thoroughbred horses are heritable, economically valuable and may affect horse welfare. The aims of this study were to test the hypotheses that (i) durability traits are heritable and (ii) genetic data may be used to predict a horse's potential to have a racecourse start. Heritability for the phenotype ‘number of 2‐ and 3‐year‐old starts’ was estimated to be urn:x-wiley:02689146:media:age12798:age12798-math-0001 = 0.11 ± 0.02 (n = 4499). A genome‐wide association study identified SNP contributions to the trait. The neurotrimin (NTM), opioid‐binding protein/cell adhesion molecule like (OPCML) and prolylcarboxypeptidase (PRCP) genes were identified as candidate genes associated with the trait. NTM functions in brain development and has been shown to have been selected during the domestication of the horse. PRCP is an established expression quantitative trait locus involved in the interaction between voluntary exercise and body composition in mice. We hypothesise that variation at these loci contributes to the motivation of the horse to exercise, which may influence its response to the demands of the training and racing environment. A random forest with mixed effects (RFME) model identified a set of SNPs that contributed to 24.7% of the heritable variation in the trait. In an independent validation set (n = 528 horses), the cohort with high genetic potential for a racecourse start had significantly fewer unraced horses (16% unraced) than did low (27% unraced) potential horses and had more favourable race outcomes among those that raced. Therefore, the information from SNPs included in the model may be used to predict horses with a greater chance of a racecourse start

    Phenomenology of flavor-mediated supersymmetry breaking

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    The phenomenology of a new economical SUSY model that utilizes dynamical SUSY breaking and gauge-mediation (GM) for the generation of the sparticle spectrum and the hierarchy of fermion masses is discussed. Similarities between the communication of SUSY breaking through a messenger sector, and the generation of flavor using the Froggatt-Nielsen (FN) mechanism are exploited, leading to the identification of vector-like messenger fields with FN fields, and the messenger U(1) as a flavor symmetry. An immediate consequence is that the first and second generation scalars acquire flavor-dependent masses, but do not violate FCNC bounds since their mass scale, consistent with effective SUSY, is of order 10 TeV. We define and advocate a minimal flavor-mediated model (MFMM), recently introduced in the literature, that successfully accommodates the small flavor-breaking parameters of the standard model using order one couplings and ratios of flavon field vevs. The mediation of SUSY breaking occurs via two-loop log-enhanced GM contributions, as well as several one-loop and two-loop Yukawa-mediated contributions for which we provide analytical expressions. The MFMM is parameterized by a small set of masses and couplings, with values restricted by several model constraints and experimental data. The next-to-lightest sparticle (NLSP) always has a decay length that is larger than the scale of a detector, and is either the lightest stau or the lightest neutralino. Similar to ordinary GM models, the best collider search strategies are, respectively, inclusive production of at least one highly ionizing track, or events with many taus plus missing energy. In addition, D^0 - \bar{D}^0 mixing is also a generic low energy signal. Finally, the dynamical generation of the neutrino masses is briefly discussed.Comment: 54 pages, LaTeX, 8 figure

    The Fayet-Iliopoulos D-term and its renormalisation in softly-broken supersymmetric theories

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    We consider the renormalisation of the Fayet-Iliopoulos D-term in a softly-broken abelian supersymmetric theory, and calculate the associated beta-function through three loops. We show that there exists (at least through three loops) a renormalisation group invariant trajectory for the coefficient of the D-term, corresponding to the conformal anomaly solution for the soft masses and couplings.Comment: 30 pages, Revtex, 15 Figures. Minor changes, and inadvertent omission of author from this abstract correcte

    The Reach of the Fermilab Tevatron and CERN LHC for Gaugino Mediated SUSY Breaking Models

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    In supersymmetric models with gaugino mediated SUSY breaking (inoMSB), it is assumed that SUSY breaking on a hidden brane is communicated to the visible brane via gauge superfields which propagate in the bulk. This leads to GUT models where the common gaugino mass m1/2m_{1/2} is the only soft SUSY breaking term to receive contributions at tree level. To obtain a viable phenomenology, it is assumed that the gaugino mass is induced at some scale McM_c beyond the GUT scale, and that additional renormalization group running takes place between McM_c and MGUTM_{GUT} as in a SUSY GUT. We assume an SU(5) SUSY GUT above the GUT scale, and compute the SUSY particle spectrum expected in models with inoMSB. We use the Monte Carlo program ISAJET to simulate signals within the inoMSB model, and compute the SUSY reach including cuts and triggers approriate to Fermilab Tevatron and CERN LHC experiments. We find no reach for SUSY by the Tevatron collider in the trilepton channel. %either with or without %identified tau leptons. At the CERN LHC, values of m1/2=1000m_{1/2}=1000 (1160) GeV can be probed with 10 (100) fb−1^{-1} of integrated luminosity, corresponding to a reach in terms of mtg⁡m_{\tg} of 2150 (2500) GeV. The inoMSB model and mSUGRA can likely only be differentiated at a linear e+e−e^+e^- collider with sufficient energy to produce sleptons and charginos.Comment: 17 page revtex file with 9 PS figure

    Shear viscosity of the Quark-Gluon Plasma from a virial expansion

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    We calculate the shear viscosity η\eta in the quark-gluon plasma (QGP) phase within a virial expansion approach with particular interest in the ratio of η\eta to the entropy density ss, i.e. η/s\eta/s. The virial expansion approach allows us to include the interactions between the partons in the deconfined phase and to evaluate the corrections to a single-particle partition function. In the latter approach we start with an effective interaction with parameters fixed to reproduce thermodynamical quantities of QCD such as energy and/or entropy density. We also directly extract the effective coupling \ga_{\rm V} for the determination of η\eta. Our numerical results give a ratio η/s≈0.097\eta/s\approx 0.097 at the critical temperature TcT_{\rm c}, which is very close to the theoretical bound of 1/(4π)1/(4\pi). Furthermore, for temperatures T≀1.8TcT\leq 1.8 T_{\rm c} the ratio η/s\eta/s is in the range of the present experimental estimates 0.1−0.30.1-0.3 at RHIC. When combining our results for η/s\eta/s in the deconfined phase with those from chiral perturbation theory or the resonance gas model in the confined phase we observe a pronounced minimum of η/s\eta/s close to the critical temperature TcT_{\rm c}.Comment: Published in Eur. Phys. J. C, 7 pages, 2 figures, 3 tabl

    Charged BTZ-like Black Holes in Higher Dimensions

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    Motivated by many worthwhile paper about (2 + 1)-dimensional BTZ black holes, we generalize them to to (n + 1)-dimensional solutions, so called BTZ-like solutions. We show that the electric field of BTZ-like solutions is the same as (2 + 1)-dimensional BTZ black holes, and also their lapse functions are approximately the same, too. By these similarities, it is also interesting to investigate the geometric and thermodynamics properties of the BTZ-like solutions. We find that, depending on the metric parameters, the BTZ-like solutions may be interpreted as black hole solutions with inner (Cauchy) and outer (event) horizons, an extreme black hole or naked singularity. Then, we calculate thermodynamics quantities and conserved quantities, and show that they satisfy the first law of thermodynamics. Finally, we perform a stability analysis in the canonical ensemble and show that the BTZ-like solutions are stable in the whole phase space.Comment: 5 pages, two column format, one figur
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