19,096 research outputs found

    Dental erosion: In vitro model of wine assessor's erosion

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    The document attached has been archived with permission from the Australian Dental Association. An external link to the publisher’s copy is included.Background: Wine makers and assessors frequently experience severe dental erosion. The objectives of this study were to develop an in vitro model of dental erosion caused by frequent wine contact with teeth, and to use this model to assess the effectiveness of a variety of methods which might protect against this form of erosion. Methods: An initial pilot study found that riesling style wine was more erosive than champagne style, and both more than claret. Wine tasting was simulated by subjecting exposed windows of enamel and root surfaces on 50 intact, extracted human teeth to 1400 one minute exposures to white wine (pH 3.2). A variety of dental materials were applied to the exposed windows on groups of teeth prior to erosive challenge, to assess their protective ability. Results: Protective resin coatings and fluoride varnishes protected both enamel and roots against wine induced erosion. A high degree of protection was provided by APF gel, with less by NaF gel. Conclusions: It was concluded that dentists may be able to help minimise erosion resulting from frequent wine-tasting in their patients by the clinical application of one or a combination of these agents at times prior to prolonged assessment periods.Tong Bee Mok, J McIntyre and D Hun

    Top-mounted inlet system feasibility for transonic-supersonic fighter aircraft

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    The more salient findings are presented of recent top inlet performance evaluations aimed at assessing the feasibility of top-mounted inlet systems for transonic-supersonic fighter aircraft applications. Top inlet flow field and engine-inlet performance test data show the influence of key aircraft configuration variables-inlet longitudinal position, wing leading-edge extension planform area, canopy-dorsal integration, and variable incidence canards-on top inlet performance over the Mach range of 0.6 to 2.0. Top inlet performance data are compared with those or more conventional inlet/airframe integrations in an effort to assess the viability of top-mounted inlet systems relative to conventional inlet installations

    Dynamical decoherence of the light induced interlayer coupling in YBa2_{2}Cu3_{3}O6+δ_{6+\delta}

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    Optical excitation of apical oxygen vibrations in YBa2_{2}Cu3_{3}O6+δ_{6+\delta} has been shown to enhance its c-axis superconducting-phase rigidity, as evidenced by a transient blue shift of the equilibrium inter-bilayer Josephson plasma resonance. Surprisingly, a transient c-axis plasma mode could also be induced above Tc_{c} by the same apical oxygen excitation, suggesting light activated superfluid tunneling throughout the pseudogap phase of YBa2_{2}Cu3_{3}O6+δ_{6+\delta}. However, despite the similarities between the above Tc_{c} transient plasma mode and the equilibrium Josephson plasmon, alternative explanations involving high mobility quasiparticle transport should be considered. Here, we report an extensive study of the relaxation of the light-induced plasmon into the equilibrium incoherent phase. These new experiments allow for a critical assessment of the nature of this mode. We determine that the transient plasma relaxes through a collapse of its coherence length rather than its carrier (or superfluid) density. These observations are not easily reconciled with quasiparticle interlayer transport, and rather support transient superfluid tunneling as the origin of the light-induced interlayer coupling in YBa2_{2}Cu3_{3}O6+δ_{6+\delta}.Comment: 27 pages (17 pages main text, 10 pages supplementary), 5 figures (main text

    Glimmers: Resolving the Privacy/Trust Quagmire

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    Many successful services rely on trustworthy contributions from users. To establish that trust, such services often require access to privacy-sensitive information from users, thus creating a conflict between privacy and trust. Although it is likely impractical to expect both absolute privacy and trustworthiness at the same time, we argue that the current state of things, where individual privacy is usually sacrificed at the altar of trustworthy services, can be improved with a pragmatic GlimmerGlimmer ofof TrustTrust, which allows services to validate user contributions in a trustworthy way without forfeiting user privacy. We describe how trustworthy hardware such as Intel's SGX can be used client-side -- in contrast to much recent work exploring SGX in cloud services -- to realize the Glimmer architecture, and demonstrate how this realization is able to resolve the tension between privacy and trust in a variety of cases

    Phase transition in a log-normal Markov functional model

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    We derive the exact solution of a one-dimensional Markov functional model with log-normally distributed interest rates in discrete time. The model is shown to have two distinct limiting states, corresponding to small and asymptotically large volatilities, respectively. These volatility regimes are separated by a phase transition at some critical value of the volatility. We investigate the conditions under which this phase transition occurs, and show that it is related to the position of the zeros of an appropriately defined generating function in the complex plane, in analogy with the Lee-Yang theory of the phase transitions in condensed matter physics.Comment: 9 pages, 5 figures. v2: Added asymptotic expressions for the convexity-adjusted Libors in the small and large volatility limits. v3: Added one reference. Final version to appear in Journal of Mathematical Physic

    The inclusion of ethnic minority patients and the role of language in telehealth trials for type 2 diabetes: A systematic review

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    BACKGROUND: Type 2 diabetes is a serious, pervasive metabolic condition that disproportionately affects ethnic minority patients. Telehealth interventions can facilitate type 2 diabetes monitoring and prevent secondary complications. However, trials designed to test the effectiveness of telehealth interventions may underrecruit or exclude ethnic minority patients, with language a potential barrier to recruitment. The underrepresentation of minorities in trials limits the external validity of the findings for this key patient demographic. OBJECTIVE: This systematic review examines (1) the research reporting practices and prevalence of ethnic minority patients included in telehealth randomized controlled trials (RCTs) targeting type 2 diabetes and the trial characteristics associated with recruiting a high proportion of minority patients, and (2) the proportion of included RCTs that report using English language proficiency as a patient screening criterion and how and why they do so. METHODS: Telehealth RCTs published in refereed journals targeting type 2 diabetes as a primary condition for adults in Western majority English-speaking countries were included. Ethnically targeted RCTs were excluded from the main review, but were included in a post hoc subgroup analysis. Abstract and full-text screening, risk of bias assessment, and data extraction were independently conducted by two reviewers. RESULTS: Of 3358 records identified in the search, 79 articles comprising 58 RCTs were included. Nearly two-thirds of the RCTs (38/58) reported on the ethnic composition of participants, with a median proportion of 23.5% patients (range 0%-97.7%). Fourteen studies (24%) that included at least 30% minority patients were all US-based, predominantly recruited from urban areas, and described the target population as underserved, financially deprived, or uninsured. Eight of these 14 studies (57%) offered intervention materials in a language other than English or employed bilingual staff. Half of all identified RCTs (29/58) included language proficiency as a participant-screening criterion. Language proficiency was operationalized using nonstandardized measures (eg, having sufficient "verbal fluency"), with only three studies providing reasons for excluding patients on language grounds. CONCLUSIONS: There was considerable variability across studies in the inclusion of ethnic minority patients in RCTs, with higher participation rates in countries with legislation to mandate their inclusion (eg, United States) than in those without such legislation (eg, United Kingdom). Less than 25% of the RCTs recruited a sizeable proportion of ethnic minorities, which raises concerns about external validity. The lack of objective measures or common procedures for assessing language proficiency across trials implies that language-related eligibility decisions are often based on trial recruiters' impressionistic judgments, which could be subject to bias. The variability and inconsistent reporting on ethnicity and other socioeconomic factors in descriptions of research participants could be more specifically emphasized in trial reporting guidelines to promote best practice

    Herschel observations of gamma-ray burst host galaxies: implications for the topology of the dusty interstellar medium

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    Long-duration gamma-ray bursts (GRBs) are indisputably related to star formation, and their vast luminosity in gamma rays pin-points regions of star formation independent of galaxy mass. As such, GRBs provide a unique tool for studying star forming galaxies out to high-z independent of luminosity. Most of our understanding of the properties of GRB hosts (GRBHs) comes from optical and near-infrared (NIR) follow-up observations, and we therefore have relatively little knowledge of the fraction of dust-enshrouded star formation that resides within GRBHs. Currently ~20% of GRBs show evidence of significant amounts of dust along the line of sight to the afterglow through the host galaxy, and these GRBs tend to reside within redder and more massive galaxies than GRBs with optically bright afterglows. In this paper we present Herschel observations of five GRBHs with evidence of being dust-rich, targeted to understand the dust attenuation properties within GRBs better. Despite the sensitivity of our Herschel observations, only one galaxy in our sample was detected (GRBH 070306), for which we measure a total star formation rate (SFR) of ~100Mstar/yr, and which had a relatively high stellar mass (log[Mstar]=10.34+0.09/-0.04). Nevertheless, when considering a larger sample of GRBHs observed with Herschel, it is clear that stellar mass is not the only factor contributing to a Herschel detection, and significant dust extinction along the GRB sightline (A_{V,GRB}>1.5~mag) appears to be a considerably better tracer of GRBHs with high dust mass. This suggests that the extinguishing dust along the GRB line of sight lies predominantly within the host galaxy ISM, and thus those GRBs with A_{V,GRB}>1~mag but with no host galaxy Herschel detections are likely to have been predominantly extinguished by dust within an intervening dense cloud.Comment: 14 pages, 7 figures. Accepted for publication in A&

    Measuring categorisation in pre-school children: new toolkit, new insights

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    Introduction: whilst recent years have witnessed considerable research into infant categorisation, its development during the pre-school period has garnered far less interest and innovation. Objective: this paper documents the development of a valid and reliable new toolkit for measuring categorisation in children, designed to allow fine-grained differentiation through four short tasks. Methods: the paper outlines how a pilot study with 55 children reduced confounding variables, ruled out several explanations for performance variations and enabled procedural refinements. It then documents a study conducted with 190 children aged 30-60 months. Results: this more sophisticated testing mechanism challenges previously accepted developmental norms and suggests both sex and socio-economic status (and their interaction) influence categorisational abilities in pre-schoolers. Conclusion: the results indicate that preschool children’s ability to categorise varies markedly, with implications for their capacity to access formal education
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