444 research outputs found
Self dual models and mass generation in planar field theory
We analyse in three space-time dimensions, the connection between abelian
self dual vector doublets and their counterparts containing both an explicit
mass and a topological mass. Their correspondence is established in the
lagrangian formalism using an operator approach as well as a path integral
approach. A canonical hamiltonian analysis is presented, which also shows the
equivalence with the lagrangian formalism. The implications of our results for
bosonisation in three dimensions are discussed.Comment: 15 pages,Revtex, No figures; several changes; revised version to
appear in Physical Review
DREDed Anomaly Mediation
We offer a guide to dimensional reduction (DRED) in theories with anomaly
mediated supersymmetry breaking. Evanescent operators proportional to epsilon
arise in the bare Lagrangian when it is reduced from d=4 to d= (4-2 epsilon)
dimensions. In the course of a detailed diagrammatic calculation, we show that
inclusion of these operators is crucial. The evanescent operators conspire to
drive the supersymmetry-breaking parameters along anomaly-mediation
trajectories across heavy particle thresholds, guaranteeing the ultraviolet
insensitivity.Comment: 24 pages. 10 figures. Uses Axodraw. Reference adde
Zeta function regularization for a scalar field in a compact domain
We express the zeta function associated to the Laplacian operator on
in terms of the zeta function associated to the Laplacian on
, where is a compact connected Riemannian manifold. This gives formulas
for the partition function of the associated physical model at low and high
temperature for any compact domain . Furthermore, we provide an exact
formula for the zeta function at any value of when is a -dimensional
box or a -dimensional torus; this allows a rigorous calculation of the zeta
invariants and the analysis of the main thermodynamic functions associated to
the physical models at finite temperature.Comment: 19 pages, no figures, to appear in J. Phys.
Personal identity (de)formation among lifestyle travellers: A double-edged sword?
This article explores the personal identity work of lifestyle travellers – individuals for whom extended leisure travel is a preferred lifestyle that they return to repeatedly. Qualitative findings from in-depth semi-structured interviews with lifestyle travellers in northern India and southern Thailand are interpreted in light of theories on identity formation in late modernity that position identity as problematic. It is suggested that extended leisure travel can provide exposure to varied cultural praxes that may contribute to a sense of social saturation. Whilst a minority of the respondents embraced a saturation of personal identity in the subjective formation of a cosmopolitan cultural identity, several of the respondents were paradoxically left with more identity questions than answers as the result of their travels
Efficacy and safety of the anti-IL-12/23 p40 monoclonal antibody, ustekinumab, in patients with active psoriatic arthritis despite conventional non-biological and biological anti-tumour necrosis factor therapy: 6-month and 1-year results of the phase 3, multicentre, double-blind, placebo-controlled, randomised PSUMMIT 2 trial
Objective: Assess ustekinumab efficacy (week 24/week 52) and safety (week 16/week 24/week 60) in patients with active psoriatic arthritis (PsA) despite treatment with conventional and/or biological anti-tumour necrosis factor (TNF) agents.
Methods: In this phase 3, multicentre, placebo-controlled trial, 312 adults with active PsA were randomised (stratified by site, weight (≤100 kg/>100 kg), methotrexate use) to ustekinumab 45 mg or 90 mg at week 0, week 4, q12 weeks or placebo at week 0, week 4, week 16 and crossover to ustekinumab 45 mg at week 24, week 28 and week 40. At week 16, patients with <5% improvement in tender/swollen joint counts entered blinded early escape (placebo→45 mg, 45 mg→90 mg, 90 mg→90 mg). The primary endpoint was ≥20% improvement in American College of Rheumatology (ACR20) criteria at week 24. Secondary endpoints included week 24 Health Assessment Questionnaire-Disability Index (HAQ-DI) improvement, ACR50, ACR70 and ≥75% improvement in Psoriasis Area and Severity Index (PASI75). Efficacy was assessed in all patients, anti-TNF-naïve (n=132) patients and anti-TNF-experienced (n=180) patients.
Results: More ustekinumab-treated (43.8% combined) than placebo-treated (20.2%) patients achieved ACR20 at week 24 (p<0.001). Significant treatment differences were observed for week 24 HAQ-DI improvement (p<0.001), ACR50 (p≤0.05) and PASI75 (p<0.001); all benefits were sustained through week 52. Among patients previously treated with ≥1 TNF inhibitor, sustained ustekinumab efficacy was also observed (week 24 combined vs placebo: ACR20 35.6% vs 14.5%, PASI75 47.1% vs 2.0%, median HAQ-DI change −0.13 vs 0.0; week 52 ustekinumab-treated: ACR20 38.9%, PASI75 43.4%, median HAQ-DI change −0.13). No unexpected adverse events were observed through week 60.
Conclusions: The interleukin-12/23 inhibitor ustekinumab (45/90 mg q12 weeks) yielded significant and sustained improvements in PsA signs/symptoms in a diverse population of patients with active PsA, including anti-TNF-experienced PsA patients
Varespladib and cardiovascular events in patients with an acute coronary syndrome: the VISTA-16 randomized clinical trial
IMPORTANCE: Secretory phospholipase A2(sPLA2) generates bioactive phospholipid products implicated in atherosclerosis. The sPLA2inhibitor varespladib has favorable effects on lipid and inflammatory markers; however, its effect on cardiovascular outcomes is unknown. OBJECTIVE: To determine the effects of sPLA2inhibition with varespladib on cardiovascular outcomes. DESIGN, SETTING, AND PARTICIPANTS: A double-blind, randomized, multicenter trial at 362 academic and community hospitals in Europe, Australia, New Zealand, India, and North America of 5145 patients randomized within 96 hours of presentation of an acute coronary syndrome (ACS) to either varespladib (n = 2572) or placebo (n = 2573) with enrollment between June 1, 2010, and March 7, 2012 (study termination on March 9, 2012). INTERVENTIONS: Participants were randomized to receive varespladib (500 mg) or placebo daily for 16 weeks, in addition to atorvastatin and other established therapies. MAIN OUTCOMES AND MEASURES: The primary efficacy measurewas a composite of cardiovascular mortality, nonfatal myocardial infarction (MI), nonfatal stroke, or unstable angina with evidence of ischemia requiring hospitalization at 16 weeks. Six-month survival status was also evaluated. RESULTS: At a prespecified interim analysis, including 212 primary end point events, the independent data and safety monitoring board recommended termination of the trial for futility and possible harm. The primary end point occurred in 136 patients (6.1%) treated with varespladib compared with 109 patients (5.1%) treated with placebo (hazard ratio [HR], 1.25; 95%CI, 0.97-1.61; log-rank P = .08). Varespladib was associated with a greater risk of MI (78 [3.4%] vs 47 [2.2%]; HR, 1.66; 95%CI, 1.16-2.39; log-rank P = .005). The composite secondary end point of cardiovascular mortality, MI, and stroke was observed in 107 patients (4.6%) in the varespladib group and 79 patients (3.8%) in the placebo group (HR, 1.36; 95% CI, 1.02-1.82; P = .04). CONCLUSIONS AND RELEVANCE: In patients with recent ACS, varespladib did not reduce the risk of recurrent cardiovascular events and significantly increased the risk of MI. The sPLA2inhibition with varespladib may be harmful and is not a useful strategy to reduce adverse cardiovascular outcomes after ACS. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01130246. Copyright 2014 American Medical Association. All rights reserved
Novel role for the innate immune receptor toll-like receptor 4 (TLR4) in the regulation of the wnt signaling pathway and photoreceptor apoptosis
Recent evidence has implicated innate immunity in regulating neuronal survival in the brain during stroke and other neurodegenerations. Photoreceptors are specialized light-detecting neurons in the retina that are essential for vision. In this study, we investigated the role of the innate immunity receptor TLR4 in photoreceptors. TLR4 activation by lipopolysaccharide (LPS) significantly reduced the survival of cultured mouse photoreceptors exposed to oxidative stress. With respect to mechanism, TLR4 suppressed Wnt signaling, decreased phosphorylation and activation of the Wnt receptor LRP6, and blocked the protective effect of the Wnt3a ligand. Paradoxically, TLR4 activation prior to oxidative injury protected photoreceptors, in a phenomenon known as preconditioning. Expression of TNFα and its receptors TNFR1 and TNFR2 decreased during preconditioning, and preconditioning was mimicked by TNFα antagonists, but was independent of Wnt signaling. Therefore, TLR4 is a novel regulator of photoreceptor survival that acts through the Wnt and TNFα pathways. © 2012 Yi et al
A cross-sectional exploratory analysis between pet ownership and sleep, exercise, health and neighborhood perceptions : The Whitehall II cohort study
A cross-sectional exploratory analysis between pet ownership and sleep, exercise, health and neighbourhood perceptions: The Whitehall II cohort study
Gill Mein (corresponding author), Robert Grant. Faculty of Health, Social Care and Education. Kingston University and St George’s University of London
Background: To explore associations between pets, and specifically dog ownership and sleep, health, exercise and neighbourhood.
Methods: Cross sectional examination of 6575 participants of the Whitehall II study aged between 59-79 years. We used self-assessed measurement scales of the Short Form (SF36), General Health Questionnaire (GHQ), Control, Autonomy, Self-realisation and Pleasure (CASP), Centre for Epidemiologic Studies Depression Scale (CES-D), sleep, exercise, and perceptions of local neighbourhood. In addition the Mini Mental State Examination which is administered to test global cognitive status (MMSE)
Results: We found 2/7 people owned a pet and of those 64% were “very” attached to their pet. Mild exercise in metabolic equivalents (MET-hours) was significantly higher in pet owners than non-owners (median 27.8 (IQR 18.1 to 41.8) vs 25.7 (IQR 16.8 to 38.7), p=0.0001), and in dog owners than other pets (median 32.3 (IQR 20.8 to 46.1) vs 25.6 (IQR 16.8 to 38.5), p<0.0001). Moderate exercise was also significantly higher in pet owners than non pet owners (median 11.8 (IQR 4.2 to 21.9) vs 9.8 (IQR 2.8 to 19.5), p<0.0001), and dog owners than owners of other pets (median 12.3 (IQR 4.2 to 22.2) vs 10.1 (3.1 to 20.0), p=0.0002) but there were no significant differences with vigorous exercise. We found that pet owners were significantly more positive about their neighbourhood than non-owners on 8/9 questions, while dog owners were (significantly) even more positive than owners of other pets on 8/9 questions. Associations with sleep were mixed, although dog owners had less trouble falling asleep than non-dog owners, with borderline statistical significance.
Conclusion: Dog owners feel more positive about their neighbourhood, do more exercise, and fall asleep more easily than non-dog owners. These results suggest that dog owners could be more likely to exercise by walking their dogs and therefore may be more familiar and positive about the area in which they walk their dog
Bird communities across varying landcover types in a Neotropical city
Urbanization poses a serious threat to local biodiversity, yet towns and cities with abundant natural features may harbor important species populations and communities. While the contribution of urban greenspaces to conservation has been demonstrated by numerous studies within temperate regions, few consider the bird communities associated with different landcovers in Neotropical cities. To begin to fill this knowledge gap, we examined how the avifauna of a wetland city in northern Amazonia (Georgetown, Guyana) varied across six urban landcover types (coastal bluespace; urban bluespace; managed greenspace; unmanaged greenspace; dense urban; sparse urban). We measured detections, species richness and a series of ground cover variables that characterized the heterogeneity of each landcover, at 114 locations across the city. We recorded >10% (98) of Guyana’s bird species in Georgetown, including taxa of conservation interest. Avian detections, richness, and community composition differed with landcover type. Indicator species analysis identified 29 species from across dietary guilds, which could be driving community composition. Comparing landcovers, species richness was highest in managed greenspaces and lowest in dense urban areas. The canal network had comparable levels of species richness to greenspaces. The waterways are likely to play a key role in enhancing habitat connectivity as they traverse densely urbanized areas. Both species and landcover information should be integrated into urban land-use planning in the rapidly urbanizing Neotropics to maximize the conservation value of cities. This is imperative in the tropics, where anthropogenic pressures on species are growing significantly, and action needs to be taken to prevent biodiversity collapse
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