1,712 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
Issues in the development of advance directives in mental health care
<i>Background</i>: Interest in advance directives in mental health care is growing internationally. There is no clear universal agreement as to what such an advance directive is or how it should function. <i>Aim</i>: To describe the range of issues embodied in the development of advance directives in mental health care. <i>Method</i>: The literature on advance directives is examined to highlight the pros and cons of different versions of advance directive. <i>Results</i>: Themes emerged around issues of terminology, competency and consent, the legal status of advance directives independent or collaborative directives and their content. Opinions vary between a unilateral legally enforceable instrument to a care plan agreed between patient and clinician. <i>Conclusion</i>: There is immediate appeal in a liberal democracy that values individual freedom and autonomy in giving weight to advance directives in mental health care. They do not, however, solve all the problems of enforced treatment and early access to treatment. They also raise new issues and highlight persistent problems. <i>Declaration</i> <i>of</i> <i>interest</i>: The research was funded by the Nuffield Foundation grant number
MNH/00015G
Studies relating to Polyunsaturated Fatty Acid (PUFA) Supplementation and Fertility in Cattle
End of project reportReproductive inefficiency has a significant impact on the economic performance of both dairy and beef herds, particularly in seasonal calving systems. Nutrition plays a fundamental role in reproduction. Furthermore, there is emerging evidence that supplemental dietary polyunsaturated fatty acids (PUFA) may increase cow fertility independent of their role as energy substrates. A number of studies have reported enhanced reproductive performance in dairy cows following dietary supplementation with sources of n-3 PUFA. However the possible mechanisms involved have not been identified and there is some inconsistency in the published literature on this topic. The objective of the research reported was to conduct a holistic examination of the effects of dietary long-chain n-3 PUFA supplementation on metabolic and reproductive responses in cattle. Such information is essential for the appropriate formulation of diets to enhance cow reproductive performance and in particular embryo survival
Gravity thaws the frozen moduli of the CP^1 lump
The slow motion of a self-gravitating CP^1 lump is investigated in the
approximation of geodesic flow on the moduli space of unit degree static
solutions M_1. It is found that moduli which are frozen in the absence of
gravity, parametrizing the lump's width and internal orientation, may vary once
gravitational effects are included. If gravitational coupling is sufficiently
strong, the presence of the lump shrinks physical space to finite volume, and
the moduli determining the boundary value of the CP^1 field thaw also. Explicit
formulae for the metric on M_1 are found in both the weak and strong coupling
regimes. The geodesic problem for weak coupling is studied in detail, and it is
shown that M_1 is geodesically incomplete. This leads to the prediction that
self-gravitating lumps are unstable.Comment: 6 pages, minor error corrected (conclusions unchanged
The L^2 geometry of spaces of harmonic maps S^2 -> S^2 and RP^2 -> RP^2
Harmonic maps from S^2 to S^2 are all weakly conformal, and so are
represented by rational maps. This paper presents a study of the L^2 metric
gamma on M_n, the space of degree n harmonic maps S^2 -> S^2, or equivalently,
the space of rational maps of degree n. It is proved that gamma is Kaehler with
respect to a certain natural complex structure on M_n. The case n=1 is
considered in detail: explicit formulae for gamma and its holomorphic
sectional, Ricci and scalar curvatures are obtained, it is shown that the space
has finite volume and diameter and codimension 2 boundary at infinity, and a
certain class of Hamiltonian flows on M_1 is analyzed. It is proved that
\tilde{M}_n, the space of absolute degree n (an odd positive integer) harmonic
maps RP^2 -> RP^2, is a totally geodesic Lagrangian submanifold of M_n, and
that for all n>1, \tilde{M}_n is geodesically incomplete. Possible
generalizations and the relevance of these results to theoretical physics are
briefly discussed.Comment: 27 pages, 2 figure
Risk and protective factors for meningococcal disease in adolescents: matched cohort study
Objective: To examine biological and social risk factors for
meningococcal disease in adolescents.
Design: Prospective, population based, matched cohort study
with controls matched for age and sex in 1:1 matching.
Controls were sought from the general practitioner.
Setting: Six contiguous regions of England, which represent
some 65% of the country’s population.
Participants: 15-19 year olds with meningococcal disease
recruited at hospital admission in six regions (representing 65%
of the population of England) from January 1999 to June 2000,
and their matched controls.
Methods: Blood samples and pernasal and throat swabs were
taken from case patients at admission to hospital and from
cases and matched controls at interview. Data on potential risk
factors were gathered by confidential interview. Data were
analysed by using univariate and multivariate conditional
logistic regression.
Results: 144 case control pairs were recruited (74 male (51%);
median age 17.6). 114 cases (79%) were confirmed
microbiologically. Significant independent risk factors for
meningococcal disease were history of preceding illness
(matched odds ratio 2.9, 95% confidence interval 1.4 to 5.9),
intimate kissing with multiple partners (3.7, 1.7 to 8.1), being a
university student (3.4, 1.2 to 10) and preterm birth (3.7, 1.0 to
13.5). Religious observance (0.09, 0.02 to 0.6) and
meningococcal vaccination (0.12, 0.04 to 0.4) were associated
with protection.
Conclusions: Activities and events increasing risk for
meningococcal disease in adolescence are different from in
childhood. Students are at higher risk. Altering personal
behaviours could moderate the risk. However, the development
of further effective meningococcal vaccines remains a key
public health priority
Oscillatory oblique stagnation-point flow toward a plane wall
Two-dimensional oscillatory oblique stagnation-point flow toward a plane wall is investigated. The problem is a eneralisation of the steady oblique stagnation-point flow examined by previous workers. Far from the wall, the flow is composed of an irrotational orthogonal stagnation-point flow with a time-periodic strength, a simple shear flow of constant vorticity, and a time-periodic uniform stream. An exact solution of the Navier-Stokes equations is sought for which the flow streamfunction depends linearly on the coordinate parallel to the wall. The problem formulation reduces to a coupled pair of partial differential equations in time and one spatial variable. The first equation describes the oscillatory orthogonal stagnation-point flow discussed by previous workers. The second equation, which couples to the first, describes the oblique component of the flow. A description of the flow velocity field, the instantaneous streamlines, and the particle paths is sought through numerical solutions of the governing equations and via asymptotic analysis
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Dynamics of earthquake nucleation process represented by the Burridge-Knopoff model
Dynamics of earthquake nucleation process is studied on the basis of the
one-dimensional Burridge-Knopoff (BK) model obeying the rate- and
state-dependent friction (RSF) law. We investigate the properties of the model
at each stage of the nucleation process, including the quasi-static initial
phase, the unstable acceleration phase and the high-speed rupture phase or a
mainshock. Two kinds of nucleation lengths L_sc and L_c are identified and
investigated. The nucleation length L_sc and the initial phase exist only for a
weak frictional instability regime, while the nucleation length L_c and the
acceleration phase exist for both weak and strong instability regimes. Both
L_sc and L_c are found to be determined by the model parameters, the frictional
weakening parameter and the elastic stiffness parameter, hardly dependent on
the size of an ensuing mainshock. The sliding velocity is extremely slow in the
initial phase up to L_sc, of order the pulling speed of the plate, while it
reaches a detectable level at a certain stage of the acceleration phase. The
continuum limits of the results are discussed. The continuum limit of the BK
model lies in the weak frictional instability regime so that a mature
homogeneous fault under the RSF law always accompanies the quasi-static
nucleation process. Duration times of each stage of the nucleation process are
examined. The relation to the elastic continuum model and implications to real
seismicity are discussed.Comment: Title changed. Changes mainly in abstract and in section 1. To appear
in European Physical Journal
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