1,935 research outputs found
Rates of medial tibiofemoral joint space narrowing in osteoarthritis studies consistent despite methodological differences
SummaryRationaleMinimum tibiofemoral joint space width in the medial compartment (JSW) is the most well-established structural outcome measure for osteoarthritis (OA) of the knee. Its usefulness as a measure of therapeutic effectiveness in short-term studies is limited by the rate and variability of joint space narrowing (JSN) in the OA population. Microfocal radiography has been shown to improve reproducibility of JSW measurement compared to standard radiography, but measurement of magnification from microfocal knee films has been problematic, and JSN is yet to be investigated in a longitudinal microfocal study.ObjectiveTo establish the effect on JSW reproducibility of a new method of magnification measurement in microfocal radiographs. To report on and compare rates of medial tibiofemoral JSN and their variations in the placebo arms of microfocal and standard radiographic clinical trials in OA, using fluoroscopic semi-flexed (SF) knee positioning. To place in the context of published estimates of rates of JSN from comparable studies.MethodsUsing microfocal radiography, 36 patients were followed at a single centre for 2 years. Using standard radiography, 86 patients were followed for 1 year at a single centre, and 549 for 2 years in a multi-centre international study. Computerised JSW measurement was undertaken using enhanced and automated versions of existing algorithms. Rates of JSN were examined in the context of a review of published rates of JSN using a variety of techniques.ResultsReproducibility of JSW measurement from microfocal radiographs was improved by the new magnification measurement. Rates of JSN were similar across the studies, but more variable when using standard radiography. The rates of JSN were also consistent with those from previously published investigations; all estimates since 2000, bar one, being consistent with the value 0.05mm/year.ConclusionMicrofocal radiography using the new method lowered the variability of the rate of JSN, but the high cost and low availability of microfocal equipment remains a barrier to its more widespread use. The consistently low but highly variable rates of JSN seen in the review suggest that continued attempts to improve radiographic and mensural techniques are unlikely to significantly reduce required sample sizes
Isoforms of transferrin in psoriasis patients abusing alcohol
The different isoforms of transferrin have been quantified by isoelectric
focusing in the sera of psoriasis patients with and without a history of
abusing alcohol. In both male and female psoriasis subjects abusing
alcohol, there were significant increases in the 2-sialylated forms by
comparison to the control subjects. Psoriasis patients who had no evidence
of alcohol abuse had similar profile for the isoforms of transferrin to
that of the controls. Other groups of patients with alcohol-induced tissue
damage, i.e. liver, brain or muscle, used as positive controls, similarly
showed significant increases in the 2-sialylated forms, by comparison to
controls. These results substantiate the current use of
carbohydrate-deficient transferrin as a sensitive marker of alcohol abuse,
particularly in subjects not drinking in excess of 60 g of ethanol/day but
showing alcohol-related psoriasis
Quantisation of twistor theory by cocycle twist
We present the main ingredients of twistor theory leading up to and including
the Penrose-Ward transform in a coordinate algebra form which we can then
`quantise' by means of a functorial cocycle twist. The quantum algebras for the
conformal group, twistor space CP^3, compactified Minkowski space CMh and the
twistor correspondence space are obtained along with their canonical quantum
differential calculi, both in a local form and in a global *-algebra
formulation which even in the classical commutative case provides a useful
alternative to the formulation in terms of projective varieties. We outline how
the Penrose-Ward transform then quantises. As an example, we show that the
pull-back of the tautological bundle on CMh pulls back to the basic instanton
on S^4\subset CMh and that this observation quantises to obtain the
Connes-Landi instanton on \theta-deformed S^4 as the pull-back of the
tautological bundle on our \theta-deformed CMh. We likewise quantise the
fibration CP^3--> S^4 and use it to construct the bundle on \theta-deformed
CP^3 that maps over under the transform to the \theta-deformed instanton.Comment: 68 pages 0 figures. Significant revision now has detailed formulae
for classical and quantum CP^
The use of incidence counts for estimation of cereal aphid populations. 3. Population development and the incidence-density relation.
Om in de praktijk gebruik te kunnen maken van incidentie (de fractie bezette halmen) voor het schatten van graanluispopulaties moet dezelfde relatie tussen dichtheid en incidentie tijdens het hele groeiseizoen gelden. Uit analyses van veldgegevens voor de graanluis Sitobion avenae blijkt dat wel het geval te zijn, zodat bepalingen van incidentie kunnen worden gebruikt om de populatiedichtheid betrouwbaar te schatte
Multibeam Maser Survey of methanol and excited OH in the Magellanic clouds: new detections and maser abundance estimates
‘The definitive version is available at www.blackwell-synergy.com.’ Copyright Blackwell Publishing DOI: 10.1111/j.1365-2966.2008.12888.xPeer reviewe
Integrin activation - the importance of a positive feedback
Integrins mediate cell adhesion and are essential receptors for the
development and functioning of multicellular organisms. Integrin activation is
known to require both ligand and talin binding and to correlate with cluster
formation but the activation mechanism and precise roles of these processes are
not yet resolved. Here mathematical modeling, with known experimental
parameters, is used to show that the binding of a stabilizing factor, such as
talin, is alone insufficient to enable ligand-dependent integrin activation for
all observed conditions; an additional positive feedback is required.Comment: in press in Bulletin of Mathematical Biolog
Noncommutative Electromagnetism As A Large N Gauge Theory
We map noncommutative (NC) U(1) gauge theory on R^d_C X R^{2n}_{NC} to U(N ->
\infty) Yang-Mills theory on R^d_C, where R^d_C is a d-dimensional commutative
spacetime while R^{2n}_{NC} is a 2n-dimensional NC space. The resulting U(N)
Yang-Mills theory on R^d_C is equivalent to that obtained by the dimensional
reduction of (d+2n)-dimensional U(N) Yang-Mills theory onto R^d_C. We show that
the gauge-Higgs system (A_\mu,\Phi^a) in the U(N -> \infty) Yang-Mills theory
on R^d_C leads to an emergent geometry in the (d+2n)-dimensional spacetime
whose metric was determined by Ward a long time ago. In particular, the
10-dimensional gravity for d=4 and n=3 corresponds to the emergent geometry
arising from the 4-dimensional N=4 vector multiplet in the AdS/CFT duality. We
further elucidate the emergent gravity by showing that the gauge-Higgs system
(A_\mu,\Phi^a) in half-BPS configurations describes self-dual Einstein gravity.Comment: 25 pages; More clarifications, to appear in Eur. Phys. J.
Notes on Exact Multi-Soliton Solutions of Noncommutative Integrable Hierarchies
We study exact multi-soliton solutions of integrable hierarchies on
noncommutative space-times which are represented in terms of quasi-determinants
of Wronski matrices by Etingof, Gelfand and Retakh. We analyze the asymptotic
behavior of the multi-soliton solutions and found that the asymptotic
configurations in soliton scattering process can be all the same as commutative
ones, that is, the configuration of N-soliton solution has N isolated localized
energy densities and the each solitary wave-packet preserves its shape and
velocity in the scattering process. The phase shifts are also the same as
commutative ones. Furthermore noncommutative toroidal Gelfand-Dickey hierarchy
is introduced and the exact multi-soliton solutions are given.Comment: 18 pages, v3: references added, version to appear in JHE
Comparison between three-dimensional linear and nonlinear tsunami generation models
The modeling of tsunami generation is an essential phase in understanding
tsunamis. For tsunamis generated by underwater earthquakes, it involves the
modeling of the sea bottom motion as well as the resulting motion of the water
above it. A comparison between various models for three-dimensional water
motion, ranging from linear theory to fully nonlinear theory, is performed. It
is found that for most events the linear theory is sufficient. However, in some
cases, more sophisticated theories are needed. Moreover, it is shown that the
passive approach in which the seafloor deformation is simply translated to the
ocean surface is not always equivalent to the active approach in which the
bottom motion is taken into account, even if the deformation is supposed to be
instantaneous.Comment: 39 pages, 16 figures; Accepted to Theoretical and Computational Fluid
Dynamics. Several references have been adde
The changing of the guard: groupwork with people who have intellectual disabilities
This paper considers the impact of service systems on group activities. It describes an inter-professional groupwork project facilitated by a social worker and a community nurse. The project provided an emancipatory experience for a group of adults who had intellectual disabilities. The group was charged with the task of reviewing and updating the recruitment and interview processes used by a 'Learning Disability Partnership Board', when employing new support workers.
The paper begins with a brief history of intellectual disability and provides a context to the underpinning philosophical belief that people should be encouraged and supported to inhabit valued social roles no matter what disability they may have. It then identifies the ways in which the sponsoring health, education and social care services impacted on the creation and development of a groupwork project. It might have been expected that the nature of the intellectual disability would have been the major influence on group process. However the paper reveals that organisational constraints had a significant impact on group functioning. Issues including, staffing budgets and transport contracts impacted on group process and function.
The results of the project show how, with adequate support, people with intellectual disability can make important decisions that have long-reaching impacts on the services
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