6,473 research outputs found

    Standing on the Shoulders of Giants: The Cleft Palate-Craniofacial Journal (1964-1989)Electronic Archive

    Get PDF
    Current research and clinical practice in cleft palate and craniofacial disorders “stands on the shoulders of giants” who came before us. To enable thirty years of seminal research articles to become digitally available to a worldwide community of students, scholars, and clinicians, a collaboration was forged in 2004 between University of Pittsburgh’s Digital Research Library (DRL) and ACPA, (with the agreement of Allen Press), to create an electronic archive of the first thirty years of the Cleft Palate Craniofacial Journal . The work was performed pro bono, by all parties

    On the Gannon-Lee Singularity Theorem in Higher Dimensions

    Full text link
    The Gannon-Lee singularity theorems give well-known restrictions on the spatial topology of singularity-free (i.e., nonspacelike geodesically complete), globally hyperbolic spacetimes. In this paper, we revisit these classic results in the light of recent developments, especially the failure in higher dimensions of a celebrated theorem by Hawking on the topology of black hole horizons. The global hyperbolicity requirement is weakened, and we expand the scope of the main results to allow for the richer variety of spatial topologies which are likely to occur in higher-dimensional spacetimes.Comment: 13 pages, no figures, to appear in Class. Quantum Gra

    Accretion column eclipses in the X-ray pulsars GX 1+4 and RX J0812.4-3114

    Full text link
    Sharp dips observed in the pulse profiles of three X-ray pulsars (GX 1+4, RX J0812.4-3114 and A 0535+26) have previously been suggested to arise from partial eclipses of the emission region by the accretion column occurring once each rotation period. We present pulse-phase spectroscopy from Rossi X-ray Timing Explorer satellite observations of GX 1+4 and RX J0812.4-3114 which for the first time confirms this interpretation. The dip phase corresponds to the closest approach of the column axis to the line of sight, and the additional optical depth for photons escaping from the column in this direction gives rise to both the decrease in flux and increase in the fitted optical depth measured at this phase. Analysis of the arrival time of individual dips in GX~1+4 provides the first measurement of azimuthal wandering of a neutron star accretion column. The column longitude varies stochastically with standard deviation 2-6 degrees depending on the source luminosity. Measurements of the phase width of the dip both from mean pulse profiles and individual eclipses demonstrates that the dip width is proportional to the flux. The variation is consistent with that expected if the azimuthal extent of the accretion column depends only upon the Keplerian velocity at the inner disc radius, which varies as a consequence of the accretion rate Mdot.Comment: 7 pages, 5 figures, accepted by MNRAS. Included reference

    Unpowered Aerodynamic Characteristics of a 15-Percent Scale Model of a Twin-Engine Commuter Aircraft

    Get PDF
    An experimental investigation was conducted in the Ames 12-Foot Pressure Wind Tunnel to determine the unpowered aerodynamic characteristics of a 15-percent-scale model of a twin-engine commuter aircraft. Model longitudinal aerodynamic characteristics were examined at discrete flap deflections for various angle-of-attack and wind-tunnel-velocity ranges with the empennage on and off. Data are presented for the basic model configuration consisting of the fuselage, wing, basic wing leading edge, double slotted flaps, midengine nacelles, and empennage. Other configurations tested include a particle-span drooped leading edge (dropped outboard of the engine nacelles), a full-span drooped leading edge, low- and high-mounted engine nacelles, and a single-slotted flap. An evaluation was made of the model mounting system by comparing data obtained with the model mounted conventionally on the wind-tunnel model-support struts and the model inverted

    The Moidart earthquakes of 4 August 2017

    Get PDF
    The Moidart earthquake of 4 August 2017 (4.0 ML) was the largest earthquake in Scotland for 18 years. The earthquake was felt widely across the west of Scotland. Only five other earthquakes of this size or greater have been observed in the period of instrumental recording from 1970 to present. Historical observations and instrumental recordings have been used to estimate that an earthquake of 4.0 ML or greater occurs somewhere in Scotland roughly every 8-9 years on average. The earthquake hypocentre was calculated using an iterative linearized method. The results suggest that the earthquake occurred in the mid-Crust at a depth of approximately 12 km. This is largely consistent with observed focal depths for other earthquakes in the region, which are distributed throughout the upper 20 km of the Crust. The strong similarity between the recorded ground motions from the mainshock and the four recorded aftershocks suggests that they all occurred within a small source volume, of the order of a few hundred metres in extent and had similar source mechanisms. The modelled source displacement spectra provide a good fit for the observed displacement spectra and suggest a moment magnitude (Mw) of 3.6 ± 0.1. This is slightly less than that expected for an earthquake with a local magnitude of 4.0 ML using commonly used empirical relationships relating local and moment magnitude, which gives an expected moment magnitude of 3.7. The calculated focal mechanism suggests that the earthquake resulted from strike-slip faulting on a fault plane that strikes either SW-NE or NW-SE and dips steeply, although the dip of both fault planes is rather poorly constrained. This is in good agreement with focal mechanisms calculated for other earthquakes across the region, which all show similar solutions. Seismicity in northwest Scotland is clustered around a number of large, steeply dipping major faults that strike either NE-SW or NW-SE suggesting that earthquake activity across the region is driven by reactivation of such fault systems by deformation associated with first-order plate motions rather than deformation associated with glacioisostatic recovery. Although there are no mapped major fault systems in the immediate vicinity of the Moidart earthquake, it seems likely that the earthquake also occurred on a steeply dipping fault that strikes either NE-SW or NW-SE but remains unmapped

    Soliton Solutions to the Einstein Equations in Five Dimensions

    Full text link
    We present a new class of solutions in odd dimensions to Einstein's equations containing either a positive or negative cosmological constant. These solutions resemble the even-dimensional Eguchi-Hanson--(anti)-de Sitter ((A)dS) metrics, with the added feature of having Lorentzian signatures. They provide an affirmative answer to the open question as to whether or not there exist solutions with negative cosmological constant that asymptotically approach AdS5/Γ_{5}/\Gamma, but have less energy than AdS5/Γ_{5}/\Gamma. We present evidence that these solutions are the lowest-energy states within their asymptotic class.Comment: 9 pages, Latex; Final version that appeared in Phys. Rev. Lett; title changed by journal from original title "Eguchi-Hanson Solitons

    Impact of stressing a pen mate on physiological responses of growing pigs

    Get PDF
    Crossbred barrows and gilts (n = 36), weighing 16.59 ± 2.1 kg, were used to test the effects of stressing a pen mate on the physiological responses of growing pigs. Pigs were randomly allotted to 6 groups after stratifying according to gender, litter origin, and body weight. Dominance order was determined within each group, and 1 to 3 d prior to the stress treatment the most- and leastdominant pigs within a group were fitted with indwelling catheters in their vena cavas. Over 3 d, groups were either: 1) isolated from audile and visual contact with stressed pigs in a separate room (non-stressed control); 2) separated by a curtain from visual contact with stressed pigs; or 3) allowed to maintain audile and visual contact with stressed pigs. Blood samples were collected 30, 15, and 0 min before exposure to the stressor (snout-snare) treatment and again at 1, 2, 3, 4, 5, 7.5, 10, 15, 20, 25, and 30 min after stressor application. Serum cortisol and plasma glucose, lactate, and nonesterified fatty acids (NEFA) concentrations were measured. There were no treatment × sampling-time interactions (P \u3e 0.17) for concentrations of cortisol, glucose, lactate or NEFA, nor were these metabolites affected by stressor treatment (P \u3e 0.42). Humoral measures of the stress response were not affected by visual and/or audile contact with pen mates undergoing a stressful event

    Charmonium properties from lattice QCD + QED: hyperfine splitting, J/ψJ/\psi leptonic width, charm quark mass and aμca_{\mu}^c

    Get PDF
    We have performed the first nf=2+1+1n_f = 2+1+1 lattice QCD computations of the properties (masses and decay constants) of ground-state charmonium mesons. Our calculation uses the HISQ action to generate quark-line connected two-point correlation functions on MILC gluon field configurations that include u/du/d quark masses going down to the physical point, tuning the cc quark mass from MJ/ψM_{J/\psi} and including the effect of the cc quark's electric charge through quenched QED. We obtain MJ/ψMηcM_{J/\psi}-M_{\eta_c} (connected) = 120.3(1.1) MeV and interpret the difference with experiment as the impact on MηcM_{\eta_c} of its decay to gluons, missing from the lattice calculation. This allows us to determine ΔMηcannihiln\Delta M_{\eta_c}^{\mathrm{annihiln}} =+7.3(1.2) MeV, giving its value for the first time. Our result of fJ/ψ=f_{J/\psi}= 0.4104(17) GeV, gives Γ(J/ψe+e)\Gamma(J/\psi \rightarrow e^+e^-)=5.637(49) keV, in agreement with, but now more accurate than experiment. At the same time we have improved the determination of the cc quark mass, including the impact of quenched QED to give mc(3GeV)\overline{m}_c(3\,\mathrm{GeV}) = 0.9841(51) GeV. We have also used the time-moments of the vector charmonium current-current correlators to improve the lattice QCD result for the cc quark HVP contribution to the anomalous magnetic moment of the muon. We obtain aμc=14.638(47)×1010a_{\mu}^c = 14.638(47) \times 10^{-10}, which is 2.5σ\sigma higher than the value derived using moments extracted from some sets of experimental data on R(e+ehadrons)R(e^+e^- \rightarrow \mathrm{hadrons}). This value for aμca_{\mu}^c includes our determination of the effect of QED on this quantity, δaμc=0.0313(28)×1010\delta a_{\mu}^c = 0.0313(28) \times 10^{-10}.Comment: Added extra discussion on QED setup, some new results to study the effects of strong isospin breaking in the sea (including new Fig. 1) and a fit stability plot for the hyperfine splitting (new Fig. 7). Version accepted for publication in PR

    Data quality predicts care quality: findings from a national clinical audit

    Get PDF
    Background: Missing clinical outcome data are a common occurrence in longitudinal studies. Data quality in clinical audit is a particular cause for concern. The relationship between departmental levels of missing clinical outcome data and care quality is not known. We hypothesise that completeness of key outcome data in a national audit predicts departmental performance. Methods: The National Clinical Audit for Rheumatoid and Early Inflammatory Arthritis (NCAREIA) collected data on care of patients with suspected rheumatoid arthritis (RA) from early 2014 to late 2015. This observational cohort study collected data on patient demographics, departmental variables, service quality measures including time to treatment, and the key RA clinical outcome measure, disease activity at baseline, and 3 months follow-up. A mixed effects model was conducted to identify departments with high/low proportions of missing baseline disease activity data with the results plotted on a caterpillar graph. A mixed effects model was conducted to assess if missing baseline disease activity predicted prompt treatment. Results: Six thousand two hundred five patients with complete treatment time data and a diagnosis of RA were recruited from 136 departments. 34.3% had missing disease activity at baseline. Mixed effects modelling identified 13 departments with high levels of missing disease activity, with a cluster observed in the Northwest of England. Missing baseline disease activity was associated with not commencing treatment promptly in an adjusted mix effects model, odds ratio 0.50 (95% CI 0.41 to 0.61, p < 0.0001). Conclusions: We have shown that poor engagement in a national audit program correlates with the quality of care provided. Our findings support the use of data completeness as an additional service quality indicator
    corecore