Radiation from a Charge Uniformly Accelerated for All Time

A recent paper of Singal [Gen. Rel. Grav. 27 (1995), 953-967] argues that a uniformly accelerated particle does not radiate, in contradiction to the consensus of the research literature over the past 30 years. This note points out some questionable aspects of Singal's argument and shows how similar calculations can lead to the opposite conclusion.Comment: LaTeX, 9 pages, to appear in General Relativity and Gravitatio

A particle swarm optimization based memetic algorithm for dynamic optimization problems

Copyright @ Springer Science + Business Media B.V. 2010.Recently, there has been an increasing concern from the evolutionary computation community on dynamic optimization problems since many real-world optimization problems are dynamic. This paper investigates a particle swarm optimization (PSO) based memetic algorithm that hybridizes PSO with a local search technique for dynamic optimization problems. Within the framework of the proposed algorithm, a local version of PSO with a ring-shape topology structure is used as the global search operator and a fuzzy cognition local search method is proposed as the local search technique. In addition, a self-organized random immigrants scheme is extended into our proposed algorithm in order to further enhance its exploration capacity for new peaks in the search space. Experimental study over the moving peaks benchmark problem shows that the proposed PSO-based memetic algorithm is robust and adaptable in dynamic environments.This work was supported by the National Nature Science Foundation of China (NSFC) under Grant No. 70431003 and Grant No. 70671020, the National Innovation Research Community Science Foundation of China under Grant No. 60521003, the National Support Plan of China under Grant No. 2006BAH02A09 and the Ministry of Education, science, and Technology in Korea through the Second-Phase of Brain Korea 21 Project in 2009, the Engineering and Physical Sciences Research Council (EPSRC) of UK under Grant EP/E060722/01 and the Hong Kong Polytechnic University Research Grants under Grant G-YH60

Drying Shrinkage Mechanisms in Portland Cement Paste

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65426/1/j.1151-2916.1987.tb05002.x.pd

General Practitioners' views on the provision of nicotine replacement therapy and bupropion.

BACKGROUND: Nicotine replacement therapies (NRT) and a new drug, bupropion, are licensed in several countries as aids to smoking cessation. General practitioners (GPs) play a crucial role in recommending or prescribing these medications. In the UK there has been discussion about whether the medications should be reimbursable by the National Health Service (NHS). This study assessed English GPs' attitudes towards reimbursement of NRT and bupropion. METHODS: Postal survey of a randomly selected national sample of GPs; 376 GPs completed the questionnaire after one reminder; effective response rate: 53%. There was no difference between the responses of GPs who responded to the initial request and those who responded only after a reminder suggesting minimal bias due to non-response. RESULTS: Attitudes of GPs were remarkably divided on most issues relating to the medications. Forty-three percent thought that bupropion should not be on NHS prescription while 42% thought that it should be (15% did not know); Fifty percent thought that NRT should not be on NHS prescription while 42% thought it should be (8% did not know). Requiring that smokers attend behavioural support programmes to be eligible to receive the medications on NHS prescription made no appreciable difference to the GPs' views. GPs were similarly divided on whether having the medications reimbursable would add unacceptably to their workload or offer a welcome opportunity to discuss smoking with their patients. A principal components analysis of responses to the individual questions on NRT and bupropion revealed that GPs' attitudes could be understood in terms of a single 'pro-con' dimension accounting for 53% of the total variance which made no distinction between the two medications. CONCLUSIONS: GPs in England appear to be divided in their attitudes to medications to aid smoking cessation and appear not to discriminate in their views between different types of medication or different aspects of their use. This suggests that their attitudes are generated by quite fundamental values. Addressing these values may be important in encouraging GPs to adhere more closely to national and international guidelines

Development of Experimental and Computational Aeroacoustic Tools for Advanced Liner Evaluation

Acoustic liners in aircraft engine nacelles suppress radiated noise. Therefore, as air travel increases, increasingly sophisticated tools are needed to maximize noise suppression. During the last 30 years, NASA has invested significant effort in development of experimental and computational acoustic liner evaluation tools. The Curved Duct Test Rig is a 152-mm by 381- mm curved duct that supports liner evaluation at Mach numbers up to 0.3 and source SPLs up to 140 dB, in the presence of user-selected modes. The Grazing Flow Impedance Tube is a 51- mm by 63-mm duct currently being fabricated to operate at Mach numbers up to 0.6 with source SPLs up to at least 140 dB, and will replace the existing 51-mm by 51-mm duct. Together, these test rigs allow evaluation of advanced acoustic liners over a range of conditions representative of those observed in aircraft engine nacelles. Data acquired with these test ducts are processed using three aeroacoustic propagation codes. Two are based on finite element solutions to convected Helmholtz and linearized Euler equations. The third is based on a parabolic approximation to the convected Helmholtz equation. The current status of these computational tools and their associated usage with the Langley test rigs is provided

Muslim communities learning about second-hand smoke (MCLASS): Study protocol for a pilot cluster randomised controlled trial

Background: In the UK, 40% of Bangladeshi and 29% of Pakistani men smoke cigarettes regularly compared to the national average of 24%. As a consequence, second-hand smoking is also widespread in their households which is a serious health hazard to non-smokers, especially children. Smoking restrictions in households can help reduce exposure to second-hand smoking. This is a pilot trial of 'Smoke Free Homes', an educational programme which has been adapted for use by Muslim faith leaders, in an attempt to find an innovative solution to encourage Pakistani- and Bangladeshi-origin communities to implement smoking restrictions in their homes. The primary objectives for this pilot trial are to establish the feasibility of conducting such an evaluation and provide information to inform the design of a future definitive study.Methods/Design: This is a pilot cluster randomised controlled trial of 'Smoke Free Homes', with an embedded preliminary health economic evaluation and a qualitative analysis. The trial will be carried out in around 14 Islamic religious settings. Equal randomisation will be employed to allocate each cluster to a trial arm. The intervention group will be offered the Smoke Free Homes package (Smoke Free Homes: a resource for Muslim religious teachers), trained in its use, and will subsequently implement the package in their religious settings. The remaining clusters will not be offered the package until the completion of the study and will form the control group. At each cluster, we aim to recruit around 50 households with at least one adult resident who smokes tobacco and at least one child or a non-smoking adult. Households will complete a household survey and a non-smoking individual will provide a saliva sample which will be tested for cotinine. All participant outcomes will be measured before and after the intervention period in both arms of the trial. In addition, a purposive sample of participants and religious leaders/teachers will take part in interviews and focus groups.Discussion: The results of this pilot study will inform the protocol for a definitive trial

An efficient and accurate method to obtain the energy-dependent Green function for general potentials

Time-dependent quantum mechanics provides an intuitive picture of particle propagation in external fields. Semiclassical methods link the classical trajectories of particles with their quantum mechanical propagation. Many analytical results and a variety of numerical methods have been developed to solve the time-dependent Schroedinger equation. The time-dependent methods work for nearly arbitrarily shaped potentials, including sources and sinks via complex-valued potentials. Many quantities are measured at fixed energy, which is seemingly not well suited for a time-dependent formulation. Very few methods exist to obtain the energy-dependent Green function for complicated potentials without resorting to ensemble averages or using certain lead-in arrangements. Here, we demonstrate in detail a time-dependent approach, which can accurately and effectively construct the energy-dependent Green function for very general potentials. The applications of the method are numerous, including chemical, mesoscopic, and atomic physics.Comment: 11 pages, to appear in the Journal of Physics: Conference Series "Time-dependent methods in Quantum Mechanics

A new conceptual framework for revenge firesetting

Revenge has frequently been acknowledged to account for a relatively large proportion of motives in deliberate firesetting. However, very little is actually known about the aetiology of revenge firesetting. Theoretical approaches to revenge-seeking behaviour are discussed. A brief review of how revenge is accounted for in existing theoretical explanations of deliberate firesetting and the known characteristics of revenge firesetters are provided. On this basis, the authors suggest, as a motive, revenge firesetting has to date been misconceptualised. A new conceptual framework is thus proposed, paying particular attention to the contextual, affective, cognitive, volitional and behavioural factors which may influence and generate a single episode of revenge firesetting. Treatment implications and suggestions for future research are also provided

Autism Spectrum Social Stories In Schools Trial 2 (ASSSIST2) : study protocol for a randomised controlled trial analysing clinical and cost-effectiveness of Social Stories™ in primary schools

BACKGROUND: Interventions designed to support children with a diagnosis of Autism Spectrum Conditions (ASC) can be time consuming, needing involvement of outside experts. Social Stories™ are a highly personalised intervention aiming to give children with ASC social information or describing an otherwise difficult situation or skill. This can be delivered daily by staff in education settings. Studies examining Social Story™ use have yielded mostly positive results but have largely been single case studies with a lack of randomised controlled trials (RCTs). Despite this numerous schools are utilising Social Stories™, and a fully powered RCT is timely. METHODS: A multi-site pragmatic cluster RCT comparing care as usual with Social Stories™ and care as usual. This study will recruit 278 participants (aged 4-11) with a clinical diagnosis of ASC, currently attending primary school in the North of England. Approximately 278 school based staff will be recruited to provide school based information about participating children with approximately 140 recruited to deliver the intervention. The study will be cluster randomised by school. Potential participants will be screened for eligibility prior to giving informed consent. Follow up data will be collected at 6 weeks and 6 months post randomisation and will assess changes in participants' social responsiveness, goal based outcomes, social and emotional health. The primary outcome measure is the Social Responsiveness Scale Second Edition (SRS-2) completed by school based staff at 6 months. Approvals have been obtained from the University of York's Research Governance Committee, Research Ethics Committee and the Health Research Authority. Study results will be submitted for publication in peer-reviewed journals and disseminated to participating families, educational staff, local authority representatives, community groups and Patient and Participant Involvement representatives. Suggestions will be made to NICE about treatment evidence dependent on findings. DISCUSSION: This study addresses a much used but currently under researched intervention and results will inform school based support for primary school children with a diagnosis of ASC. TRIAL REGISTRATION: The trial is registered on the ISRCTN registry (registration number: ISRCTN11634810). The trial was retrospectively registered on 23rd April 2019