818 research outputs found

    On the free-precession candidate PSR B1828-11: Evidence for increasing deformation

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    We observe that the periodic variations in spin-down rate and beam-width of the radio pulsar PSR B1828-11 are getting faster. In the context of a free precession model, this corresponds to a decrease in the precession period PfpP_{\mathrm{fp}}. We investigate how a precession model can account for such a decrease in PfpP_{\mathrm{fp}}, in terms of an increase over time in the absolute biaxial deformation (âˆŁÏ”pâˆŁâˆŒ10−8|\epsilon_{\mathrm{p}}|{\sim}10^{-8}) of this pulsar. We perform a Bayesian model comparison against the 'base' precession model (with constant Ï”p\epsilon_{\mathrm{p}}) developed in Ashton et al (2016), and we obtain decisive odds in favour of a time-varying deformation. We study two types of time-variation: (i) a linear drift with a posterior estimate of ϔ˙p∌10−18 s−1\dot{\epsilon}_{\mathrm{p}}{\sim}10^{-18}\,\mathrm{s}^{-1} and odds of 107510^{75} compared to the base-model, and (ii) NN discrete positive jumps in Ï”p\epsilon_{\mathrm{p}} with very similar odds to the linear Ï”p\epsilon_{\mathrm{p}}-drift model. The physical mechanism explaining this behaviour is unclear, but the observation could provide a crucial probe of the interior physics of neutron stars. We also place an upper bound on the rate at which the precessional motion is damped, and translate this into a bound on a dissipative mutual friction-type coupling between the star's crust and core

    Webcam Delivery of the Lidcombe Program for Preschool Children Who Stutter: A Randomised Controlled Trial

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    Early intervention provides children who stutter with the best opportunity to avoid the lifelong complications associated with stuttering. Access to effective treatment, in particular, the Lidcombe Program, provides preschool children with the best chance to overcome their stuttering. Currently many children are unable to access such efficacious treatment due to distance and lifestyle factors. One solution to this problem is to deliver the treatment via webcam over the internet. This service delivery model was designed to increase access to timely, best-practice intervention for those who are currently unable to access treatment. That model was thought to be able to produce efficiency rates similar to those of traditional clinic treatment. Further, it provides a method of service delivery that: (1) improves access to evidence-based best-practice stuttering treatment for children, (2) improves access to specialist speech pathologists and quality services, (3) reduces costs and resources involved with outreach service provision, (4) provides more convenient home-based treatment for young children, and (5) ensures more equitable service delivery for rural and remote preschool children and their families. A Phase I study showed that webcam delivery of the Lidcombe Program was a viable treatment delivery model (O’Brian, Smith & Onslow, 2012). This thesis further investigates delivery of the Lidcombe Program for preschool children using the internet and a webcam. The modification in this project, compared to previous, low-tech telehealth (phone and mail) trials of the Lidcombe Program, allowed the principles of standard delivery of the Lidcombe Program to remain relatively unchanged. This was due primarily to the use of a webcam and live videoconferencing. The speech pathologist-parent-child triad was preserved, with all parties having clinic contact. Real-time measurements, observation and education for parent implementation of the program were also achieved through this medium. Thus, treatment could be delivered mostly in accordance with the program treatment guide (Packman et al., 2011, p. 1). The design for this project was a parallel, open plan, Phase III noninferiority randomised controlled trial (RCT). The control group received standard delivery of the Lidcombe Program (Packman, et al., 2011) in a traditional clinic setting. The experimental group received the Lidcombe Program within their homes using a computer, a webcam, the internet and a live video calling program (Skype). The primary outcome measures – the number of consultations and speech pathologist hours to attain entry into Stage 2 – evaluated treatment efficiency. The secondary outcomes – stuttering reduction as measured by parent evaluated severity ratings, investigated treatment efficacy, as did quantitative and qualitative data obtained from parent questionnaires. The number of weeks to attain Stage 2 entry was also measured. Initially, 66 children were assessed for this trial. Eleven were ineligible and six withdrew during the assessment process, with 49 participants being randomised. Of these, 24 were assigned to the control arm and 25 to the experimental arm. Due to time restrictions associated with the student’s candidature, not all 18-month data were collected in time for inclusion in this thesis. Pretreatment data are reported for all 49 participants. Data for all 43 participants active in the trial 9 months postrandomisation are also reported. Stage 2 entry data are available for the 35 participants (71% of the total cohort) who reached Stage 2 by December 31st 2012. Results for both groups showed no significant difference between the number of consultations and the number of weeks to Stage 2. Efficacy measures showed no significant difference between the groups in stuttering reduction. A further secondary outcome measure was parent responses to a questionnaire at entry into Stage 2. Similarly, there was no significant difference between the two groups when asked about speech pathologist-child rapport, speech pathologist-parent rapport, ease of learning treatment, severity ratings and ability to adapt treatment. Further, two-thirds of clinic families said they would choose webcam treatment in the future. Webcam parents reported no difficulty in seeking out their own resources and did not feel treatment within their home was invasive. Webcam families listed convenience and comfort as the main advantages of webcam treatment, with technical difficulties as the main disadvantage. All webcam families would choose this same method for future stuttering treatment. The thesis concludes with a discussion of the speech pathologist’s role, consultation logistics and additional qualitative observations from the webcam group. These include convenience, treatment readiness, defining clinical space, trends in clinical transfer, clinical application, limitations and future directions. Overall, this thesis demonstrates that the findings from a Phase III RCT investigating the efficiency and efficacy of stuttering treatment for preschool support the use of webcam and internet to increase access to timely and appropriate stuttering intervention. The potential for community translation of these findings is considerable; children as young as 3 years of age can receive the same stuttering treatment within their homes as they would within a clinic; they can expect no difference in outcomes or experience. This is significant given that children as young as 2 years of age can be negatively affected by their stuttering. No longer do children who stutter need to be disadvantaged by where they live or by the skills of the closest speech pathologist. They can now access evidence-based treatment within their homes

    Facial masculinity is related to perceived age, but not perceived health

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    Variation in women's preferences for male facial masculinity may reflect variation in attraction to immunocompetence or to maturity. This paper reports two studies on (a) the interrelationships between women's preferences for masculinity, apparent health, and age in male faces and (b) the extent to which manipulating each of these characteristics affects women's attributions of the remaining characteristics. Both studies were carried out with a large sample of the general public (Studies 1a and 2a) and independently in a laboratory environment with smaller undergraduate samples (Studies 1b and 2b). In both samples, masculinity and age preferences were positively related, and masculinity preferences were not associated with preferences for apparent health. There was also a positive relationship between perceived age and perceived masculinity in both samples, but evidence for a link between perceptions of masculinity and health was equivocal. Collectively, these findings suggest that variation in women's preferences for masculine proportions in male faces reflect variation in attraction to male age and do not support a strict immunocompetence explanation of preferences for facial masculinity

    Results of the First Coincident Observations by Two Laser-Interferometric Gravitational Wave Detectors

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    We report an upper bound on the strain amplitude of gravitational wave bursts in a waveband from around 800Hz to 1.25kHz. In an effective coincident observing period of 62 hours, the prototype laser interferometric gravitational wave detectors of the University of Glasgow and Max Planck Institute for Quantum Optics, have set a limit of 4.9E-16, averaging over wave polarizations and incident directions. This is roughly a factor of 2 worse than the theoretical best limit that the detectors could have set, the excess being due to unmodelled non-Gaussian noise. The experiment has demonstrated the viability of the kind of observations planned for the large-scale interferometers that should be on-line in a few years time.Comment: 11 pages, 2 postscript figure

    Reduction of Couplings in Quantum Field Theories with applications in Finite Theories and the MSSM

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    We apply the method of reduction of couplings in a Finite Unified Theory and in the MSSM. The method consists on searching for renormalization group invariant relations among couplings of a renormalizable theory holding to all orders in perturbation theory. It has a remarkable predictive power since, at the unification scale, it leads to relations between gauge and Yukawa couplings in the dimensionless sectors and relations involving the trilinear terms and the Yukawa couplings, as well as a sum rule among the scalar masses and the unified gaugino mass in the soft breaking sector. In both the MSSM and the FUT model we predict the masses of the top and bottom quarks and the light Higgs in remarkable agreement with the experiment. Furthermore we also predict the masses of the other Higgses, as well as the supersymmetric spectrum, both being in very confortable agreement with the LHC bounds on Higgs and supersymmetric particles.Comment: 18 pages, 4 figures. To appear in the proceedings of LT-10, Varna. Based on invited talks given at: LT-10, Varna; PACT-2013, Madrid; SQS'2013, Dubna; CORFU 2013, Corfu, and in several invited seminar

    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
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