12,819 research outputs found

    A single case study of articulatory adaptation during acoustic mimicry

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    The distribution of fine-grained phonetic variation can be observed in the speech of members of welldefined social groups. It is evident that such variation must somehow be able to propagate through a speech community from speaker to hearer. However, technological barriers have meant that close and direct study of the articulatory links of this speaker-hearer chain has not, to date, been possible. We present the results of a singlecase study using an ultrasound-based method to investigate temporal and configurational lingual adaptation during mimicry. Our study focuses on allophonic variants of postvocalic /r/ found in speech from Central Scotland. Our results show that our informant was able to adjust tongue gesture timing towards that of the stimulus, but did not alter tongue configuration

    The use of conversation mapping to frame key perceptual issues facing the general dental practice system in England

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    <b>Objective</b>: To demonstrate the use of a novel qualitative methodology namely conversation mapping, which can be used to capture differences in stakeholder perspectives and give a root definition of the problem in a complex policy area. The methodology is used in the context of the changes introduced in the English general dental practice system in April 2006, to investigate the key issues facing the system, as perceived by general dental practitioners (GDPs). <b>Basic research design</b>: From a broad trigger statement, three transformational statements were produced. Each participant recorded their contribution on a hard diagrammatic form as a ‘map’, with others responding with their own written comment, thus generating three conversation maps. Thematic analysis resulted in the generation of a preliminary model summarising key perceptual issues. <b>Results</b>: The five emergent themes identified were: financing, dentists’ wants/needs, the role of the public and patients, system goals and policy level decision making. Financing was identified as the core category to which all other categories were related. <b>Conclusions</b>: Conversation mapping, a methodology arising from a systems approach, can be used to develop a ‘rich picture’ of an oral health care system in order to define the core problem within this policy area. Findings suggest that GDPs identify the financing of the system as a fundamental source of problems within the general dental practice system. This appears to be at variance with the perception of policy makers, who report a more limited view, identifying the system of remuneration as the ‘heart of the problem’

    Analyzing liquids

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    The "Battle of the Sexes": A Genetic Model with Limit Cycle Behavior

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    A two-locus genetic model, based on Dawkin's "sex war" game, with the fitness of the genotypes at each locus depending on the gene frequencies at the other, is shown to give rise to a stable limit cycle. The mathematical analysis involves averaging techniques and elliptic integrals

    Gibbons-Hawking M-branes

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    We present new M2 and M5-brane solutions in M-theory based on transverse Gibbons-Hawking spaces. These solutions provide realizations of fully localized type IIA D2/D6 and NS5/D6 brane intersections. One novel feature of these solutions is that the metric functions depend on more than two transverse coordinates (unlike all the other previous known solutions). All the solutions have eight preserved supersymmetries and the world-volume theories of the NS5-branes are new non-local, non-gravitational, six dimensional, T-dual little string theories with eight supersymmetries. We discuss the limits in which the dynamics of the D2 and NS5-branes decouple from the bulk for these solutions.Comment: 32 pages, 7 figures, few sentences added, a couple of typos corrected, to appear in JHE

    The Upper Critical Field in Disordered Two-Dimensional Superconductors

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    We present calculations of the upper critical field in superconducting films as a function of increasing disorder (as measured by the normal state resistance per square). In contradiction to previous work, we find that there is no anomalous low-temperature positive curvature in the upper critical field as disorder is increased. We show that the previous prediction of this effect is due to an unjustified analytical approximation of sums occuring in the perturbative calculation. Our treatment includes both a careful analysis of first-order perturbation theory, and a non-perturbative resummation technique. No anomalous curvature is found in either case. We present our results in graphical form.Comment: 11 pages, 8 figure

    Comment on "New Experimental Limit for the Electric Dipole Moment of the Neutron"

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    A new limit for the neutron electric dipole moment has been recently reported. This new limit is obtained by combining the result from a previous experiment with the result from a more recent experiment that has much worse statistical accuracy. We show that the old result has a systematic error possibly four times greater than the new limit, and under the circumstances, averaging of the old and new results is statistically invalid. The conclusion is that it would be more appropriate to quote two independent but mutually supportive limits as obtained from each experiment separately.Comment: 7 pages, 2 figure

    Androgens in a female primate: relationships with reproductive status, age, dominance rank, fetal sex and secondary sexual color

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    A comprehensive understanding of the role of androgens in reproduction, behavior and morphology requires the examination of female, as well as male, hormone profiles. However, we know far less about the biological significance of androgens in females than in males. We investigated the relationships between fecal androgen (immunoreactive testosterone) levels and reproductive status, age, dominance rank, fetal sex and a secondary sexual trait (facial color) in semi-free-ranging female mandrills, using samples collected from 19 reproductively mature females over 13 months. Fecal androgens varied with reproductive status, being highest during gestation. Fecal androgens began to increase at 3 months of gestation, and peaked at 5 months. This pattern is more similar to that found in a platyrrhine than in other cercopithecine species, suggesting that such patterns are not necessarily phylogenetically constrained. Fecal androgens did not vary systematically with rank, in contrast to the relationship we have reported for male mandrills, and in line with sex differences in how rank is acquired and maintained. Offspring sex was unrelated to fecal androgens, either prior to conception or during gestation, contrasting with studies of other primate species. Mean facial color was positively related to mean fecal androgens across females, reflecting the same relationship in male mandrills. However, the relationship between color and androgens was negative within females. Future studies of the relationship between female androgens and social behaviour, reproduction and secondary sexual traits will help to elucidate the factors underlying the similarities and differences found between the sexes and among studies

    Change blindness in a dynamic scene due to endogenous override of exogenous attentional cues

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    Change blindness is a failure to detect changes if the change occurs during a mask or distraction. Without distraction, it is assumed that the visual transients associated with the change will automatically capture attention (exogenous control) leading to detection. However, visual transients are a defining feature of naturalistic dynamic scenes. Are artificial distractions needed to hide changes to a dynamic scene? Do the temporal demands of the scene instead lead to greater endogenous control that may result in viewers missing a change in plain sight? In the present study we pitted endogenous and exogenous factors against each other during a card trick. Complete change blindness was demonstrated even when a salient highlight was inserted coincident with the change. These results indicate strong endogenous control of attention during dynamic scene viewing and its ability to override exogenous influences even when it is to the detriment of accurate scene representation
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