Variably positioned guide vanes for aerodynamic choking

A choking device to cause a sonic barrier to be formed which reduces the transmission of noise in a direction opposed to the direction of air flow in a compressor that may be part of an aircraft gas turbine engine is described. The noise reduction is accomplished by proper shaping and movement of inlet guide vanes, and an actuator is connected to selected guide vanes to effect movement by programmed amounts as required to choke or partially choke within the design range of the axial-flow-air compressor

Advanced inlet duct noise reduction concepts

A progress report is given on the implications of inlet noise reduction on aircraft direct operating costs (DOC). It considers treated inlet rings, various other inlet noise reduction concepts, and forward-speed effects. The report was limited to relatively well-established approaches to inlet noise reduction, such as acoustic liners and fixed-geometry/high-subsonic-speed inlets which are the focus of considerable current research activity. All of the concepts discussed are of a "passive" nature, i.e., no moving parts or electrical feedback systems

Survey of inlet noise reduction concepts for gas turbine engines

An overview is given of advanced concepts for the suppression of noise in the inlets of gas turbine engines. Inlet geometric and operating parameters are presented and design criteria for suppression methods are discussed. Noise suppression concepts are described, the directions of current research are reviewed. Problem areas requiring further work are indicated. Well established approaches to inlet noise reduction - namely, acoustic liners and high subsonic Mach number inlets which are the focus of considerable current research activity are considered along with the acoustic absorption and watet vapor injection

The School Improvement Partnership Programme: Sustaining Collaboration and Enquiry to Tackle Educational Inequity

No abstract available

The School Improvement Partnership Programme: Using Collaboration and Enquiry to tackle Educational Inequity

No abstract available

The impact of a reduction in fluoride concentration in the Malaysian water supply on the prevalence of fluorosis and dental caries

Objective To assess the prevalence and severity of dental fluorosis and caries among Malaysian children following the reduction in fluoride concentration from 0.7 to 0.5 parts per million (ppm) in the public water supply. Methods This study involved lifelong residents aged 9‐ and 12‐year‐olds in fluoridated and nonfluoridated areas in Malaysia (n = 1155). In the fluoridated area, children aged 12 years and 9 years were exposed to 0.7 and 0.5 ppm, respectively, at the times when maxillary central incisors developed. Standardized photographs of maxillary central incisors were blind scored for fluorosis using Dean's criteria. Dental caries was examined using ICDAS‐II criteria. Results The prevalence of fluorosis (Dean's score ≥ 2) among children in the fluoridated area (35.7%, 95% CI: 31.9%‐39.6%) was significantly higher (P < 0.001) than children in the nonfluoridated area (5.5%, 95% CI: 3.6%‐7.4%). Of those in the fluoridated area, the prevalence of fluorosis decreased from 38.4% (95% CI: 33.1%‐44.3%) for 12‐year‐olds to 31.9% (95% CI: 27.6%‐38.2%) for 9‐year‐olds, although this difference was not statistically significant (P = 0.139). The mean caries experience in the permanent dentition was significantly lower in the fluoridated area than in the nonfluoridated area for both age groups (P < 0.05). In the multivariate models, the difference in the differences of caries experience between fluoridated and nonfluoridated areas remained statistically significant. This suggests that caries‐preventive effect is still maintained at 0.5 ppm. Conclusion Findings indicate that the change in fluoride level from 0.7 to 0.5 ppm has reduced fluorosis and maintains a caries‐preventive effect. Although there is a reduction in fluorosis prevalence, the difference was not statistically significant

Parental decisions about children's oral health behaviour - relative or absolute?

Objectives To test the extent to which parents' judgements about their children's oral health behaviour conform to the principles of a specific theory of cognitive decision making – Range-frequency Theory. Methods Experimental study with an opportunity sample of 121 parents of young children (3–6 years old) living in areas of relative deprivation in South Wales. Parents were allocated to four different experimental groups, and each completed a pen-and-paper exercise, which involved being presented with (and rating) how often other parents brushed their children's teeth. The brushing frequencies presented varied between the groups, directly test the rank and range principle of Range-frequency Theory. Results Parents' ratings of other toothbrushing frequencies were predicted by the range and rank principle of Range-frequency Theory. A comparison between Group 1 and Group 2 showed that parents' ratings of similar brushing frequencies were affected by their relative rank among other brushing frequencies presented. A comparison between Group 3 and Group 4 showed that parents in a group who were presented with a very high brushing frequency (21 times a week) rated all other brushing frequencies as relatively less healthy than the comparison group. Conclusions The principles of Range-frequency Theory predicted parents' judgement about children's oral health behaviour – specifically toothbrushing frequency. These findings provide a theoretical framework on which to develop future oral health education and interventions aimed at promoting twice-daily toothbrushing to parents of young children

К проблеме демократизации правоохранительных структур

Данная статья посвящена вопросам демократизации и реорганизации правоохранительных структур. Автор статьи фокусирует внимание на актуальных проблемах правоохранительных органов, предлагает пути их эффективного разрешения.Ця стаття присвячена питанням демократизації та реорганізації правоохоронних структур. Автор статті фокусує увагу на актуальних проблемах правоохоронних органів, пропонує шляхи їх ефективного вирішення.This article is devoted to questions of democratization and reorganization of law-enforcement structures. Author of the article focuses attention on the actual problems of Law-enforcement bodies, offers ways of their solution

Reasons for placement and replacement of crowns in general dental practice

Objectives The aim of this study was to investigate the reasons for placement and replacement of crowns in general dental practice. Methods Forty general dental practitioners recorded the principal reason for the provision of new (initial) and replacement crowns for a maximum of up to 20 patients over a 20-week period. Results A total of 664 patients received 783 crowns during the period of this study. Of these, 69% (n = 542) were new (initial) placements and 31% (n = 241) were replacements. Overall, tooth fracture (45%, n = 241) was the most frequently reported reason for new/ initial crown placements. Aesthetics (21%, n = 53) and secondary/recurrent caries (20%; n = 47) were the most frequent reasons for crown replacement. Maxillary premolars (27%, n = 145) and mandibular molars (25%, n = 137) were the teeth that received most initial crown placements. In contrast, maxillary incisors (50%, n = 115) were the most common teeth to receive a replacement crown. Dentists were more likely to replace a crown if they had not placed the original crown: 74% of replacement crowns (n = 178) were placed by a different dentist. Most patients had only one crown placed or replaced per course of treatment (n = 611; 90%). Conclusions The results of this study reveal the prescribing habits of dentists in relation to provision of initial and replacement crowns. The vast majority of patients had only one crown provided per course of treatment, which is probably a reflection of funding schemes and changing patterns of oral health. This sample reported fewer replacement crowns than previous studies. In keeping with existing literature, crowns were more frequently replaced when the treating dentist had not placed the initial crown. However, against this, more replacements were provided for more long-standing patients (5+ years attendance) compared to those with shorter attendance history (<5 years). In an area where high quality evidence is lacking, further consensus on the need for placement and replacement crowns is needed. Such information would assist dentists to provide high-quality care and commissioners in developing an evidence-based service