974 research outputs found
Classical orbital paramagnetism in non-equilibrium steady state
We report the results of our numerical simulation of classical-dissipative
dynamics of a charged particle subjected to a non-markovian stochastic forcing.
We find that the system develops a steady-state orbital magnetic moment in the
presence of a static magnetic field. Very significantly, the sign of the
orbital magnetic moment turns out to be {\it paramagnetic} for our choice of
parameters, varied over a wide range. This is shown specifically for the case
of classical dynamics driven by a Kubo-Anderson type non-markovian noise.
Natural spatial boundary condition was imposed through (1) a soft (harmonic)
confining potential, and (2) a hard potential, approximating a reflecting wall.
There was no noticeable qualitative difference. What appears to be crucial to
the orbital magnetic effect noticed here is the non-markovian property of the
driving noise chosen. Experimental realization of this effect on the laboratory
scale, and its possible implications are briefly discussed. We would like to
emphasize that the above steady-state classical orbital paramagnetic moment
complements, rather than contradicts the Bohr-van Leeuwen (BvL) theorem on the
absence of classical orbital diamagnetism in thermodynamic equilibrium.Comment: 6 pages, 4 figures, Has appeared in Journal of Astrophysics and
Astronomy special issue on 'Physics of Neutron Stars and Related Objects',
celebrating the 75th birth-year of G. Srinivasa
Facilitating return to work through early specialist health-based interventions (FRESH): protocol for a feasibility randomised controlled trial
Background
Over one million people sustain traumatic brain injury each year in the UK and more than 10 % of these are moderate or severe injuries, resulting in cognitive and psychological problems that affect the ability to work. Returning to work is a primary rehabilitation goal but fewer than half of traumatic brain injury survivors achieve this. Work is a recognised health service outcome, yet UK service provision varies widely and there is little robust evidence to inform rehabilitation practice. A single-centre cohort comparison suggested better work outcomes may be achieved through early occupational therapy targeted at job retention. This study aims to determine whether this intervention can be delivered in three new trauma centres and to conduct a feasibility, randomised controlled trial to determine whether its effects and cost effectiveness can be measured to inform a definitive trial.
Methods/design
Mixed methods study, including feasibility randomised controlled trial, embedded qualitative studies and feasibility economic evaluation will recruit 102 people with traumatic brain injury and their nominated carers from three English UK National Health Service (NHS) trauma centres. Participants will be randomised to receive either usual NHS rehabilitation or usual rehabilitation plus early specialist traumatic brain injury vocational rehabilitation delivered by an occupational therapist. The primary objective is to assess the feasibility of conducting a definitive trial; secondary objectives include measurement of protocol integrity (inclusion/exclusion criteria, intervention adherence, reasons for non-adherence) recruitment rate, the proportion of eligible patients recruited, reasons for non-recruitment, spectrum of TBI severity, proportion of and reasons for loss to follow-up, completeness of data collection, gains in face-to-face Vs postal data collection and the most appropriate methods of measuring primary outcomes (return to work, retention) to determine the sample size for a larger trial.
Discussion
To our knowledge, this is the first feasibility randomised controlled trial of a vocational rehabilitation health intervention specific to traumatic brain injury. The results will inform the design of a definitive trial
The Spin Structure of the Nucleon
We present an overview of recent experimental and theoretical advances in our
understanding of the spin structure of protons and neutrons.Comment: 84 pages, 29 figure
Polarised Quark Distributions in the Nucleon from Semi-Inclusive Spin Asymmetries
We present a measurement of semi-inclusive spin asymmetries for positively
and negatively charged hadrons from deep inelastic scattering of polarised
muons on polarised protons and deuterons in the range 1
GeV. Compared to our previous publication on this subject, with the new
data the statistical errors have been reduced by nearly a factor of two.
From these asymmetries and our inclusive spin asymmetries we determine the
polarised quark distributions of valence quarks and non-strange sea quarks at
=10 GeV. The polarised valence quark distribution, , is positive and the polarisation increases with . The polarised
valence quark distribution, , is negative and the non-strange
sea distribution, , is consistent with zero over the measured
range of . We find for the first moments , and
, where we assumed
. We also determine for the first time the
second moments of the valence distributions .Comment: 17 page
Angular and Current-Target Correlations in Deep Inelastic Scattering at HERA
Correlations between charged particles in deep inelastic ep scattering have
been studied in the Breit frame with the ZEUS detector at HERA using an
integrated luminosity of 6.4 pb-1. Short-range correlations are analysed in
terms of the angular separation between current-region particles within a cone
centred around the virtual photon axis. Long-range correlations between the
current and target regions have also been measured. The data support
predictions for the scaling behaviour of the angular correlations at high Q2
and for anti-correlations between the current and target regions over a large
range in Q2 and in the Bjorken scaling variable x. Analytic QCD calculations
and Monte Carlo models correctly describe the trends of the data at high Q2,
but show quantitative discrepancies. The data show differences between the
correlations in deep inelastic scattering and e+e- annihilation.Comment: 26 pages including 10 figures (submitted to Eur. J. Phys. C
Zebrafish as a new model to study effects of periodontal pathogens on cardiovascular diseases.
Porphyromonas gingivalis (Pg) is a keystone pathogen in the aetiology of chronic periodontitis. However, recent evidence suggests that the bacterium is also able to enter the bloodstream, interact with host cells and tissues, and ultimately contribute to the pathogenesis of cardiovascular disease (CVD). Here we established a novel zebrafish larvae systemic infection model showing that Pg rapidly adheres to and penetrates the zebrafish vascular endothelium causing a dose- and time-dependent mortality with associated development of pericardial oedemas and cardiac damage. The in vivo model was then used to probe the role of Pg expressed gingipain proteases using systemically delivered gingipain-deficient Pg mutants, which displayed significantly reduced zebrafish morbidity and mortality compared to wild-type bacteria. In addition, we used the zebrafish model to show efficacy of a gingipain inhibitor (KYT) on Pg-mediated systemic disease, suggesting its potential use therapeutically. Our data reveal the first real-time in vivo evidence of intracellular Pg within the endothelium of an infection model and establishes that gingipains are crucially linked to systemic disease and potentially contribute to CVD
Beauty photoproduction measured using decays into muons in dijet events in ep collisions at =318 GeV
The photoproduction of beauty quarks in events with two jets and a muon has
been measured with the ZEUS detector at HERA using an integrated luminosity of
110 pb. The fraction of jets containing b quarks was extracted from the
transverse momentum distribution of the muon relative to the closest jet.
Differential cross sections for beauty production as a function of the
transverse momentum and pseudorapidity of the muon, of the associated jet and
of , the fraction of the photon's momentum participating in
the hard process, are compared with MC models and QCD predictions made at
next-to-leading order. The latter give a good description of the data.Comment: 32 pages, 6 tables, 7 figures Table 6 and Figure 7 revised September
200
Plastisol Foaming Process. Decomposition of the Foaming Agent, Polymer Behavior in the Corresponding Temperature Range and Resulting Foam Properties
The decomposition of azodicarbonamide, used as foaming agent in PVC - plasticizer (1/1) plastisols was studied by DSC. Nineteen different plasticizers, all belonging to the ester family, two being polymeric (polyadipates), were compared. The temperature of maximum decomposition rate (in anisothermal regime at 5 K min-1 scanning rate), ranges between 434 and 452 K. The heat of decomposition ranges between 8.7 and 12.5 J g -1. Some trends of variation of these parameters appear significant and are discussed in terms of solvent (matrix) and viscosity effects on the decomposition reactions. The shear modulus at 1 Hz frequency was determined at the temperature of maximum rate of foaming agent decomposition, and differs significantly from a sample to another. The foam density was determined at ambient temperature and the volume fraction of bubbles was used as criterion to judge the efficiency of the foaming process. The results reveal the existence of an optimal shear modulus of the order of 2 kPa that corresponds roughly to plasticizer molar masses of the order of 450 ± 50 g mol-1. Heavier plasticizers, especially polymeric ones are too difficult to deform. Lighter plasticizers such as diethyl phthalate (DEP) deform too easily and presumably facilitate bubble collapse
Towards accurate and precise T1 and extracellular volume mapping in the myocardium: a guide to current pitfalls and their solutions
Mapping of the longitudinal relaxation time (T1) and extracellular volume (ECV) offers a means of identifying pathological changes in myocardial tissue, including diffuse changes that may be invisible to existing T1-weighted methods. This technique has recently shown strong clinical utility for pathologies such as Anderson- Fabry disease and amyloidosis and has generated clinical interest as a possible means of detecting small changes in diffuse fibrosis; however, scatter in T1 and ECV estimates offers challenges for detecting these changes, and bias limits comparisons between sites and vendors. There are several technical and physiological pitfalls that influence the accuracy (bias) and precision (repeatability) of T1 and ECV mapping methods. The goal of this review is to describe the most significant of these, and detail current solutions, in order to aid scientists and clinicians to maximise the utility of T1 mapping in their clinical or research setting. A detailed summary of technical and physiological factors, issues relating to contrast agents, and specific disease-related issues is provided, along with some considerations on the future directions of the field. Towards accurate and precise T1 and extracellular volume mapping in the myocardium: a guide to current pitfalls and their solutions. Available from: https://www.researchgate.net/publication/317548806_Towards_accurate_and_precise_T1_and_extracellular_volume_mapping_in_the_myocardium_a_guide_to_current_pitfalls_and_their_solutions [accessed Jun 13, 2017]
De Novo Truncating Mutations in WASF1 Cause Intellectual Disability with Seizures.
Next-generation sequencing has been invaluable in the elucidation of the genetic etiology of many subtypes of intellectual disability in recent years. Here, using exome sequencing and whole-genome sequencing, we identified three de novo truncating mutations in WAS protein family member 1 (WASF1) in five unrelated individuals with moderate to profound intellectual disability with autistic features and seizures. WASF1, also known as WAVE1, is part of the WAVE complex and acts as a mediator between Rac-GTPase and actin to induce actin polymerization. The three mutations connected by Matchmaker Exchange were c.1516C>T (p.Arg506Ter), which occurs in three unrelated individuals, c.1558C>T (p.Gln520Ter), and c.1482delinsGCCAGG (p.Ile494MetfsTer23). All three variants are predicted to partially or fully disrupt the C-terminal actin-binding WCA domain. Functional studies using fibroblast cells from two affected individuals with the c.1516C>T mutation showed a truncated WASF1 and a defect in actin remodeling. This study provides evidence that de novo heterozygous mutations in WASF1 cause a rare form of intellectual disability
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