13,030 research outputs found
A single case study of articulatory adaptation during acoustic mimicry
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
<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 âmapâ, 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, dentistsâ 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 ârich pictureâ 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 âheart
of the problemâ
The "Battle of the Sexes": A Genetic Model with Limit Cycle Behavior
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
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
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"
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
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
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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