Peculiar Velocities of Nonlinear Structure: Voids in McVittie Spacetime

As a study of peculiar velocities of nonlinear structure, we analyze the model of a relativistic thin-shell void in the expanding universe. (1) Adopting McVittie (MV) spacetime as a background universe, we investigate the dynamics of an uncompensated void with negative MV mass. Although the motion itself is quite different from that of a compensated void, as shown by Haines & Harris (1993), the present peculiar velocities are not affected by MV mass. (2) We discuss how precisely the formula in the linear perturbation theory applies to nonlinear relativistic voids, using the results in (1) as well as the previous results for the homogeneous background (Sakai, Maeda, & Sato 1993). (3) We re-examine the effect of the cosmic microwave background radiation. Contrary to the results of Pim & Lake (1986, 1988), we find that the effect is negligible. We show that their results are due to inappropriate initial conditions. Our results (1)-(3) suggest that the formula in the linear perturbation theory is approximately valid even for nonlinear voids.Comment: 12 pages, aastex, 4 ps figures separate, Fig.2 added, to appear in Ap

Auto-calibration of ultrasonic lubricant-film thickness measurements

The measurement of oil film thickness in a lubricated component is essential information for performance monitoring and design. It is well established that such measurements can be made ultrasonically if the lubricant film is modelled as a collection of small springs. The ultrasonic method requires that component faces are separated and a reference reflection recorded in order to obtain a reflection coefficient value from which film thickness is calculated. The novel and practically useful approach put forward in this paper and validated experimentally allows reflection coefficient measurement without the requirement for a reference. This involves simultaneously measuring the amplitude and phase of an ultrasonic pulse reflected from a layer. Provided that the acoustic properties of the substrate are known, the theoretical relationship between the two can be fitted to the data in order to yield reflection coefficient amplitude and phase for an infinitely thick layer. This is equivalent to measuring a reference signal directly, but importantly does not require the materials to be separated. The further valuable aspect of this approach, which is demonstrated experimentally, is its ability to be used as a self-calibrating routine, inherently compensating for temperature effects. This is due to the relationship between the amplitude and phase being unaffected by changes in temperature which cause unwanted changes to the incident pulse. Finally, error analysis is performed showing how the accuracy of the results can be optimized. A finding of particular significance is the strong dependence of the accuracy of the technique on the amplitude of reflection coefficient input data used. This places some limitations on the applicability of the technique. © 2008 IOP Publishing Ltd

Daily emollient during infancy for prevention of eczema: the BEEP randomised controlled trial.

BACKGROUND: Skin barrier dysfunction precedes eczema development. We tested whether daily use of emollient in the first year could prevent eczema in high-risk children. METHODS: We did a multicentre, pragmatic, parallel-group, randomised controlled trial in 12 hospitals and four primary care sites across the UK. Families were approached via antenatal or postnatal services for recruitment of term infants (at least 37 weeks' gestation) at high risk of developing eczema (ie, at least one first-degree relative with parent-reported eczema, allergic rhinitis, or asthma, diagnosed by a doctor). Term newborns with a family history of atopic disease were randomly assigned (1:1) to application of emollient daily (either Diprobase cream or DoubleBase gel) for the first year plus standard skin-care advice (emollient group) or standard skin-care advice only (control group). The randomisation schedule was created using computer-generated code (stratified by recruiting centre and number of first-degree relatives with atopic disease) and participants were assigned to groups using an internet-based randomisation system. The primary outcome was eczema at age 2 years (defined by UK working party criteria) with analysis as randomised regardless of adherence to allocation for participants with outcome data collected, and adjusting for stratification variables. This trial is registered with ISRCTN, ISRCTN21528841. Data collection for long-term follow-up is ongoing, but the trial is closed to recruitment. FINDINGS: 1394 newborns were randomly assigned to study groups between Nov 19, 2014, and Nov 18, 2016; 693 were assigned to the emollient group and 701 to the control group. Adherence in the emollient group was 88% (466 of 532) at 3 months, 82% (427 of 519) at 6 months, and 74% (375 of 506) at 12 months in those with complete questionnaire data. At age 2 years, eczema was present in 139 (23%) of 598 infants with outcome data collected in the emollient group and 150 (25%) of 612 infants in the control group (adjusted relative risk 0·95 [95% CI 0·78 to 1·16], p=0·61; adjusted risk difference -1·2% [-5·9 to 3·6]). Other eczema definitions supported the results of the primary analysis. Mean number of skin infections per child in year 1 was 0·23 (SD 0·68) in the emollient group versus 0·15 (0·46) in the control group; adjusted incidence rate ratio 1·55 (95% CI 1·15 to 2·09). INTERPRETATION: We found no evidence that daily emollient during the first year of life prevents eczema in high-risk children and some evidence to suggest an increased risk of skin infections. Our study shows that families with eczema, asthma, or allergic rhinitis should not use daily emollients to try and prevent eczema in their newborn. FUNDING: National Institute for Health Research Health Technology Assessment

Daily emollient during infancy for prevention of eczema: the BEEP randomised controlled trial.

BACKGROUND: Skin barrier dysfunction precedes eczema development. We tested whether daily use of emollient in the first year could prevent eczema in high-risk children. METHODS: We did a multicentre, pragmatic, parallel-group, randomised controlled trial in 12 hospitals and four primary care sites across the UK. Families were approached via antenatal or postnatal services for recruitment of term infants (at least 37 weeks' gestation) at high risk of developing eczema (ie, at least one first-degree relative with parent-reported eczema, allergic rhinitis, or asthma, diagnosed by a doctor). Term newborns with a family history of atopic disease were randomly assigned (1:1) to application of emollient daily (either Diprobase cream or DoubleBase gel) for the first year plus standard skin-care advice (emollient group) or standard skin-care advice only (control group). The randomisation schedule was created using computer-generated code (stratified by recruiting centre and number of first-degree relatives with atopic disease) and participants were assigned to groups using an internet-based randomisation system. The primary outcome was eczema at age 2 years (defined by UK working party criteria) with analysis as randomised regardless of adherence to allocation for participants with outcome data collected, and adjusting for stratification variables. This trial is registered with ISRCTN, ISRCTN21528841. Data collection for long-term follow-up is ongoing, but the trial is closed to recruitment. FINDINGS: 1394 newborns were randomly assigned to study groups between Nov 19, 2014, and Nov 18, 2016; 693 were assigned to the emollient group and 701 to the control group. Adherence in the emollient group was 88% (466 of 532) at 3 months, 82% (427 of 519) at 6 months, and 74% (375 of 506) at 12 months in those with complete questionnaire data. At age 2 years, eczema was present in 139 (23%) of 598 infants with outcome data collected in the emollient group and 150 (25%) of 612 infants in the control group (adjusted relative risk 0·95 [95% CI 0·78 to 1·16], p=0·61; adjusted risk difference -1·2% [-5·9 to 3·6]). Other eczema definitions supported the results of the primary analysis. Mean number of skin infections per child in year 1 was 0·23 (SD 0·68) in the emollient group versus 0·15 (0·46) in the control group; adjusted incidence rate ratio 1·55 (95% CI 1·15 to 2·09). INTERPRETATION: We found no evidence that daily emollient during the first year of life prevents eczema in high-risk children and some evidence to suggest an increased risk of skin infections. Our study shows that families with eczema, asthma, or allergic rhinitis should not use daily emollients to try and prevent eczema in their newborn. FUNDING: National Institute for Health Research Health Technology Assessment

Implementation Research Is Needed to Achieve International Health Goals

Sanders and Haines discuss the "knowledge-implementation gap" and identify key obstacles to correcting the gap

Addressing Climate Change Impacts on Health

Climate change is a global health emergency, with impacts felt most acutely by vulnerable populations and communities. This paper explores health risks from climate change in a global context, setting out key risks and actions towards addressing these. In the context of COP27, it draws in a focus on Egypt as a case study throughout to exemplify the risks faced by countries which are particularly vulnerable to the health impacts of climate change. This policy working paper has been produced by the Academy of Scientific Research and Technology in Egypt, with contributions from the UK Universities Climate Network, through an academic collaboration ahead of COP27 in Egypt in 2022

Achieving the Millennium Development Goals: Does Mental Health Play a Role?

Miranda and Patel argue that mental disorders are among the most important causes of disability and premature mortality in developing countries

A Comparison of Wood Density between Classical Cremonese and Modern Violins

Classical violins created by Cremonese masters, such as Antonio Stradivari and Giuseppe Guarneri Del Gesu, have become the benchmark to which the sound of all violins are compared in terms of their abilities of expressiveness and projection. By general consensus, no luthier since that time has been able to replicate the sound quality of these classical instruments. The vibration and sound radiation characteristics of a violin are determined by an instrument's geometry and the material properties of the wood. New test methods allow the non-destructive examination of one of the key material properties, the wood density, at the growth ring level of detail. The densities of five classical and eight modern violins were compared, using computed tomography and specially developed image-processing software. No significant differences were found between the median densities of the modern and the antique violins, however the density difference between wood grains of early and late growth was significantly smaller in the classical Cremonese violins compared with modern violins, in both the top (Spruce) and back (Maple) plates (p = 0.028 and 0.008, respectively). The mean density differential (SE) of the top plates of the modern and classical violins was 274 (26.6) and 183 (11.7) gram/liter. For the back plates, the values were 128 (2.6) and 115 (2.0) gram/liter. These differences in density differentials may reflect similar changes in stiffness distributions, which could directly impact vibrational efficacy or indirectly modify sound radiation via altered damping characteristics. Either of these mechanisms may help explain the acoustical differences between the classical and modern violins

Improving the use of research evidence in guideline development: 15. Disseminating and implementing guidelines

BACKGROUND: The World Health Organization (WHO), like many other organisations around the world, has recognised the need to use more rigorous processes to ensure that health care recommendations are informed by the best available research evidence. This is the 15(th )of a series of 16 reviews that have been prepared as background for advice from the WHO Advisory Committee on Health Research to WHO on how to achieve this. OBJECTIVES: In this review we address strategies for the implementation of recommendations in health care. METHODS: We examined overviews of systematic reviews of interventions to improve health care delivery and health care systems prepared by the Cochrane Effective Practice and Organisation of Care (EPOC) group. We also conducted searches using PubMed and three databases of methodological studies for existing systematic reviews and relevant methodological research. We did not conduct systematic reviews ourselves. Our conclusions are based on the available evidence, consideration of what WHO and other organisations are doing and logical arguments. KEY QUESTIONS AND ANSWERS: What should WHO do to disseminate and facilitate the uptake of recommendations? • WHO should choose strategies to implement their guidelines from among those which have been evaluated positively in the published literature on implementation research • Because the evidence base is weak and modest to moderate effects, at best, can be anticipated, WHO should promote rigorous evaluations of implementation strategies. What should be done at headquarters, by regional offices and in countries? • Adaptation and implementation of WHO guidelines should be done locally, at the national or sub-national level. • WHO headquarters and regional offices should support the development and evaluation of implementation strategies by local authorities