11,978 research outputs found

    Report of the Education and Development Group of the National Midwifery Recruitment and Retention Six Point Action Plan

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    Final report of the Education Group written for the Chief Nursing Officer for England, Dame, Professor Christine Beasley. Paul Lewis chaired the Education Group and also co-wrote the publication

    Melodia : A Comprehensive Course in Sight-Singing (Solfeggio)

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    Melodia is a 1904 book designed to teach sight-singing. The educational plan is by Samuel W. Cole; the exercises were written and selected by Leo R. Lewis. Melodia is presented here as a complete edition and has also been divided into its four separate books.https://scholarworks.sjsu.edu/oer/1000/thumbnail.jp

    The synergistic effects of slip ring-brush design and materials

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    The design, fabrication, and subsequent testing of four power slip rings for synchronous orbit application are described. The synergistic effects of contact materials and slip ring-brush design are studied by means of frequent and simultaneous recording of friction, wear, and electrical noise. Data generated during the test period are presented along with post test analysis data

    The synergistic effects of slip ring-brush design and materials

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    Synergistic effects of slip ring-brush design and fabrication for vacuum application determined by friction, wear, electrical noise, and dielectric strength dat

    Scale-Dependent Bias of Galaxies from Baryonic Acoustic Oscillations

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    Baryonic acoustic oscillations (BAOs) modulate the density ratio of baryons to dark matter across large regions of the Universe. We show that the associated variation in the mass-to-light ratio of galaxies should generate an oscillatory, scale-dependent bias of galaxies relative to the underlying distribution of dark matter. A measurement of this effect would calibrate the dependence of the characteristic mass-to-light ratio of galaxies on the baryon mass fraction in their large scale environment. This bias, though, is unlikely to significantly affect measurements of BAO peak positions.Comment: 6 pages, 3 figures, submitted to MNRA

    One simulation to fit them all - changing the background parameters of a cosmological N-body simulation

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    We demonstrate that the output of a cosmological N-body simulation can, to remarkable accuracy, be scaled to represent the growth of large-scale structure in a cosmology with parameters similar to but different from those originally assumed. Our algorithm involves three steps: a reassignment of length, mass and velocity units, a relabelling of the time axis, and a rescaling of the amplitudes of individual large-scale fluctuation modes. We test it using two matched pairs of simulations. Within each pair, one simulation assumes parameters consistent with analyses of the first-year WMAP data. The other has lower matter and baryon densities and a 15% lower fluctuation amplitude, consistent with analyses of the three-year WMAP data. The pairs differ by a factor of a thousand in mass resolution, enabling performance tests on both linear and nonlinear scales. Our scaling reproduces the mass power spectra of the target cosmology to better than 0.5% on large scales (k < 0.1 h/Mpc) both in real and in redshift space. In particular, the BAO features of the original cosmology are removed and are correctly replaced by those of the target cosmology. Errors are still below 3% for k < 1 h/Mpc. Power spectra of the dark halo distribution are even more precisely reproduced, with errors below 1% on all scales tested. A halo-by-halo comparison shows that centre-of-mass positions and velocities are reproduced to better than 90 kpc/h and 5%, respectively. Halo masses, concentrations and spins are also reproduced at about the 10% level, although with small biases. Halo assembly histories are accurately reproduced, leading to central galaxy magnitudes with errors of about 0.25 magnitudes and a bias of about 0.13 magnitudes for a representative semi-analytic model.Comment: 14 pages, 12 figures. Submitted to MNRA

    How covariant is the galaxy luminosity function?

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    We investigate the error properties of certain galaxy luminosity function (GLF) estimators. Using a cluster expansion of the density field, we show how, for both volume and flux limited samples, the GLF estimates are covariant. The covariance matrix can be decomposed into three pieces: a diagonal term arising from Poisson noise; a sample variance term arising from large-scale structure in the survey volume; an occupancy covariance term arising due to galaxies of different luminosities inhabiting the same cluster. To evaluate the theory one needs: the mass function and bias of clusters, and the conditional luminosity function (CLF). We use a semi-analytic model (SAM) galaxy catalogue from the Millennium run N-body simulation and the CLF of Yang et al. (2003) to explore these effects. The GLF estimates from the SAM and the CLF qualitatively reproduce results from the 2dFGRS. We also measure the luminosity dependence of clustering in the SAM and find reasonable agreement with 2dFGRS results for bright galaxies. However, for fainter galaxies, L<L*, the SAM overpredicts the relative bias by ~10-20%. We use the SAM data to estimate the errors in the GLF estimates for a volume limited survey of volume V~0.13 [Gpc/h]^3. We find that different luminosity bins are highly correlated: for L<L* the correlation coefficient is r>0.5. Our theory is in good agreement with these measurements. These strong correlations can be attributed to sample variance. For a flux-limited survey of similar volume, the estimates are only slightly less correlated. We explore the importance of these effects for GLF model parameter estimation. We show that neglecting to take into account the bin-to-bin covariances can lead to significant systematic errors in best-fit parameters.Comment: 19 pages, 12 figures. Accepted for publication in MNRAS. Refs updated; Fig 6 added; Figs 7 and 10 improve

    From trial to population: a study of a family-based community intervention for childhood overweight implemented at scale.

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    OBJECTIVES: To assess how outcomes associated with participation in a family-based weight management intervention (MEND 7-13, Mind, Exercise, Nutrition..Do it!) for childhood overweight or obesity implemented at scale in the community vary by child, family, neighbourhood and MEND programme characteristics. METHODS/SUBJECTS: Intervention evaluation using prospective service level data. Families (N=21,132) with overweight children are referred, or self-refer, to MEND. Families (participating child and one parent/carer) attend two sessions/week for 10 weeks (N=13,998; N=9563 with complete data from 1788 programmes across England). Sessions address diet and physical activity through education, skills training and motivational enhancement. MEND was shown to be effective in obese children in a randomised controlled trial (RCT). Outcomes were mean change in body mass index (BMI), age- and sex-standardised BMI (zBMI), self-esteem (Rosenberg scale) and psychological distress (Strengths and Difficulties Questionnaire) after the 10-week programme. Relationships between the outcome and covariates were tested in multilevel models adjusted for the outcome at baseline. RESULTS: After adjustment for covariates, BMI reduced by mean 0.76 kg m(-2) (s.e.=0.021, P<0.0001), zBMI reduced by mean 0.18 (s.e.=0.0038, P<0.0001), self-esteem score increased by 3.53 U  (s.e.=0.13, P<0.0001) and psychological distress score decreased by 2.65 U (s.e.=0.31, P<0.0001). Change in outcomes varied by participant, family, neighbourhood and programme factors. Generally, outcomes improved less among children from less advantaged backgrounds and in Asian compared with white children. BMI reduction under service conditions was slightly but not statistically significantly less than in the earlier RCT. CONCLUSIONS: The MEND intervention, when delivered at scale, is associated with improved BMI and psychosocial outcomes on average, but may work less well for some groups of children, and so has the potential to widen inequalities in these outcomes. Such public health interventions should be implemented to achieve sustained impact for all groups
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