2,668 research outputs found
Orientational order on curved surfaces - the high temperature region
We study orientational order, subject to thermal fluctuations, on a fixed
curved surface. We derive, in particular, the average density of zeros of
Gaussian distributed vector fields on a closed Riemannian manifold. Results are
compared with the density of disclination charges obtained from a Coulomb gas
model. Our model describes the disordered state of two dimensional objects with
orientational degrees of freedom, such as vector ordering in Langmuir
monolayers and lipid bilayers above the hexatic to fluid transition.Comment: final version, 13 Pages, 2 figures, uses iopart.cl
Uncorking the potential of wine language for young wine tourists
Effective communication with consumers underpins growth in wine knowledge that, in turn, contributes to growth in wine consumption. Indeed, tasting notes may enhance consumers’ experiences of wine. Yet wine language is full of fuzzy concepts. In this chapter, we consider the language used to talk about wine, specifically the humanlike features of wine (e.g., wine is described as honest, sexy, shy, or brooding). We demonstrate that metaphoric language is integral to the experience of wine and influences consumer behaviour. We discuss practical implications for the cellar door experience, and for effective and ethical wine communication. We conclude that metaphoric language is a pedagogical and cultural platform for engaging younger wine tourists in the cellar door experience, which is a significant revenue source for micro, small, and medium wineries
Psychological interventions in asthma
Asthma is a multifactorial chronic respiratory disease characterised by recurrent episodes of airway obstruction. The current management of asthma focuses principally on pharmacological treatments, which have a strong evidence base underlying their use. However, in clinical practice, poor symptom control remains a common problem for patients with asthma. Living with asthma has been linked with psychological co-morbidity including anxiety, depression, panic attacks and behavioural factors such as poor adherence and suboptimal self-management. Psychological disorders have a higher-than-expected prevalence in patients with difficult-to-control asthma. As psychological considerations play an important role in the management of people with asthma, it is not surprising that many psychological therapies have been applied in the management of asthma. There are case reports which support their use as an adjunct to pharmacological therapy in selected individuals, and in some clinical trials, benefit is demonstrated, but the evidence is not consistent. When findings are quantitatively synthesised in meta-analyses, no firm conclusions are able to be drawn and no guidelines recommend psychological interventions. These inconsistencies in findings may in part be due to poor study design, the combining of results of studies using different interventions and the diversity of ways patient benefit is assessed. Despite this weak evidence base, the rationale for psychological therapies is plausible, and this therapeutic modality is appealing to both patients and their clinicians as an adjunct to conventional pharmacological treatments. What are urgently required are rigorous evaluations of psychological therapies in asthma, on a par to the quality of pharmaceutical trials. From this evidence base, we can then determine which interventions are beneficial for our patients with asthma management and more specifically which psychological therapy is best suited for each patient
Quantum critical phenomena of long-range interacting bosons in a time-dependent random potential
We study the superfluid-insulator transition of a particle-hole symmetric
system of long-range interacting bosons in a time-dependent random potential in
two dimensions, using the momentum-shell renormalization-group method. We find
a new stable fixed point with non-zero values of the parameters representing
the short- and long-range interactions and disorder when the interaction is
asymptotically logarithmic. This is contrasted to the non-random case with a
logarithmic interaction, where the transition is argued to be first-order, and
to the Coulomb interaction case, where either a first-order transition or
an XY-like transition is possible depending on the parameters. We propose that
our model may be relevant in studying the vortex liquid-vortex glass transition
of interacting vortex lines in point-disordered type-II superconductors.Comment: 10 pages, 3 figure
B(H) Constitutive Relations Near H_c1 in Disordered Superconductors
We provide a self-contained account of the B vs. H constitutive relation near
H_c1 in Type II superconductors with various types of quenched random disorder.
The traditional Abrikosov result B ~ [ln (H - H_c1)]^{-2}, valid in the absence
of disorder and thermal fluctuations, changes significantly in the presence of
disorder. Moreover, the constitutive relations will depend strongly on the type
of disorder. In the presence of point disorder, B ~ (H - H_c1)^{3/2} in
three-dimensional (thick) superconductors, as shown by Nattermann and Lipowsky.
In two-dimensional (thin film) superconductors with point disorder, B ~ (H -
H_c1). In the presence of parallel columnar disorder, we find that B ~ exp[-C /
(H - H_c1)] in three dimensions, while B ~ exp[-K / (H - H_c1)^{1/2}] in two
dimensions. In the presence of nearly isotropically splayed disorder, we find
that B ~ (H - H_c1)^{3/2} in both two and three dimensions.Comment: 37 pages, 12 figures included in text; submitted to Physica
On centralizer algebras for spin representations
We give a presentation of the centralizer algebras for tensor products of
spinor representations of quantum groups via generators and relations. In the
even-dimensional case, this can be described in terms of non-standard
q-deformations of orthogonal Lie algebras; in the odd-dimensional case only a
certain subalgebra will appear. In the classical case q = 1 the relations boil
down to Lie algebra relations
The effect of stimulus variability on children\u2019s judgements of quantity
This study investigates the effect of stimulus variability on development of the ability to make quantity judgements related to area. Participants were 241 children (aged 4, 5, 6, 8, and 12 years) and 82 university students, who were asked to compare the quantities in 2 sets of 5 chocolate bars of constant width but variable length. Participants indicated which set contained more chocolate or that the amounts of chocolate were equal. Judgement accuracy of 12-year-olds and adults decreased monotonically as the variance of bar lengths increased. In younger children, performance was low when variance was very low or very high, but accuracy was higher for intermediate levels of variance, thus resulting in an inverted U-shaped effect. This pattern was confirmed in a second experiment in which we controlled for a possible age-related response bias against \u201cequal\u201d judgements. Findings suggest that judgements of quantity are based on a mixture of learned heuristics and comparisons of approximate quantity representations, both of which develop throughout childhood
Interaction effects in non-Hermitian models of vortex physics
Vortex lines in superconductors in an external magnetic field slightly tilted
from randomly-distributed parallel columnar defects can be modeled by a system
of interacting bosons in a non-Hermitian vector potential and a random scalar
potential. We develop a theory of the strongly-disordered non-Hermitian boson
Hubbard model using the Hartree-Bogoliubov approximation and apply it to
calculate the complex energy spectra, the vortex tilt angle and the tilt
modulus of (1+1)-dimensional directed flux line systems. We construct the phase
diagram associated with the flux-liquid to Bose-glass transition and find that,
close to the phase boundary, the tilted flux liquid phase is characterized by a
band of localized excitations, with two mobility edges in its low-energy
spectrum.Comment: 19 pages, 19 figures, To appear in Phys. Rev.
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