204 research outputs found
Confinement from new global defect structures
We investigate confinement from new global defect structures in three spatial
dimensions. The global defects arise in models described by a single real
scalar field, governed by special scalar potentials. They appear as
electrically, magnetically or dyonically charged structures. We show that they
induce confinement, when they are solutions of effective QCD-like field
theories in which the vacua are regarded as color dielectric media with an
anti-screening property. As expected, in three spatial dimensions the
monopole-like global defects generate the Coulomb potential as part of several
confining potentials.Comment: RevTex4, 7 pages, 1 figure. Version to appear in Eur. Phys. J.
The ALICE Transition Radiation Detector: Construction, operation, and performance
The Transition Radiation Detector (TRD) was designed and built to enhance the capabilities of the ALICE detector at the Large Hadron Collider (LHC). While aimed at providing electron identification and triggering, the TRD also contributes significantly to the track reconstruction and calibration in the central barrel of ALICE. In this paper the design, construction, operation, and performance of this detector are discussed. A pion rejection factor of up to 410 is achieved at a momentum of 1 GeV/c in p-Pb collisions and the resolution at high transverse momentum improves by about 40% when including the TRD information in track reconstruction. The triggering capability is demonstrated both for jet, light nuclei, and electron selection. (c) 2017 CERN for the benefit of the Authors. Published by Elsevier B.V
Planck Intermediate Results II: Comparison of Sunyaev–Zeldovich measurements from Planck and from the Arcminute Microkelvin Imager for 11 galaxy clusters
A comparison is presented of Sunyaev–Zeldovich measurements for 11 galaxy clusters as obtained by Planck and by the ground-based interferom- eter, the Arcminute Microkelvin Imager. Assuming a universal spherically-symmetric Generalised Navarro, Frenk & White (GNFW) model for the cluster gas pressure profile, we jointly constrain the integrated Compton-Y parameter (Y500) and the scale radius (θ500) of each cluster. Our resulting constraints in the Y500 − θ500 2D parameter space derived from the two instruments overlap significantly for eight of the clusters, although, overall, there is a tendency for AMI to find the Sunyaev–Zeldovich signal to be smaller in angular size and fainter than Planck. Significant discrepancies exist for the three remaining clusters in the sample, namely A1413, A1914, and the newly-discovered Planck cluster PLCKESZ G139.59+24.18. The robustness of the analysis of both the Planck and AMI data is demonstrated through the use of detailed simulations, which also discount confusion from residual point (radio) sources and from diffuse astrophysical foregrounds as possible explanations for the discrepancies found. For a subset of our cluster sample, we have investigated the dependence of our results on the assumed pressure profile by repeating the analysis adopting the best-fitting GNFW profile shape which best matches X-ray observations. Adopting the best-fitting profile shape from the X-ray data does not, in general, resolve the discrepancies found in this subset of five clusters. Though based on a small sample, our results suggest that the adopted GNFW model may not be sufficiently flexible to describe clusters universally
Risk, Timing, and Predictors of Disease Flare After Discontinuation of Anti–Tumor Necrosis Factor Therapy in Children With Polyarticular Forms of Juvenile Idiopathic Arthritis With Clinically Inactive Disease
© 2018, American College of Rheumatology Objective: To determine the frequency, time to flare, and predictors of disease flare upon withdrawal of anti–tumor necrosis factor (anti-TNF) therapy in children with polyarticular forms of juvenile idiopathic arthritis (JIA) who demonstrated ≥6 months of continuous clinically inactive disease. Methods: In 16 centers 137 patients with clinically inactive JIA who were receiving anti-TNF therapy (42% of whom were also receiving methotrexate [MTX]) were prospectively followed up. If the disease remained clinically inactive for the initial 6 months of the study, anti-TNF was stopped and patients were assessed for flare at 1, 2, 3, 4, 6, and 8 months. Life-table analysis, t-tests, chi-square test, and Cox regression analysis were used to identify independent variables that could significantly predict flare by 8 months or time to flare. Results: Of 137 patients, 106 (77%) maintained clinically inactive disease while receiving anti-TNF therapy for the initial 6 months and were included in the phase of the study in which anti-TNF therapy was stopped. Stopping anti-TNF resulted in disease flare in 39 (37%) of 106 patients by 8 months. The mean/median ± SEM time to flare was 212/250 ± 9.77 days. Patients with shorter disease duration at enrollment, older age at onset and diagnosis, shorter disease duration prior to experiencing clinically inactive disease, and shorter time from onset of clinically inactive disease to enrollment were found to have significantly lower hazard ratios for likelihood of flare by 8 months (P \u3c 0.05). Conclusion: Over one-third of patients with polyarticular JIA with sustained clinically inactive disease will experience a flare by 8 months after discontinuation of anti-TNF therapy. Several predictors of lower likelihood of flare were identified
AMPA receptor GluA2 subunit defects are a cause of neurodevelopmental disorders.
AMPA receptors (AMPARs) are tetrameric ligand-gated channels made up of combinations of GluA1-4 subunits encoded by GRIA1-4 genes. GluA2 has an especially important role because, following post-transcriptional editing at the Q607 site, it renders heteromultimeric AMPARs Ca2+-impermeable, with a linear relationship between current and trans-membrane voltage. Here, we report heterozygous de novo GRIA2 mutations in 28 unrelated patients with intellectual disability (ID) and neurodevelopmental abnormalities including autism spectrum disorder (ASD), Rett syndrome-like features, and seizures or developmental epileptic encephalopathy (DEE). In functional expression studies, mutations lead to a decrease in agonist-evoked current mediated by mutant subunits compared to wild-type channels. When GluA2 subunits are co-expressed with GluA1, most GRIA2 mutations cause a decreased current amplitude and some also affect voltage rectification. Our results show that de-novo variants in GRIA2 can cause neurodevelopmental disorders, complementing evidence that other genetic causes of ID, ASD and DEE also disrupt glutamatergic synaptic transmission
Do financial incentives for delivering health promotion counselling work? Analysis of smoking cessation activities stimulated by the quality and outcomes framework
<p>Abstract</p> <p>Background</p> <p>A substantial fraction of UK general practitioners' salaries is now intended to reflect the quality of care provided. This performance-related pay system has probably improved aspects of primary health care but, using the observational data available, disentangling the impacts of different types of targets set within this unique payment system is challenging.</p> <p>Discussion</p> <p>Financial incentives undoubtedly influence GPs' activities, however, those aimed at encouraging GPs' delivery of health promotion counselling may not always have the effects intended. There is strong, observational evidence that targets and incentives intended to increase smoking cessation counselling by GPs have merely increased their propensity to record this activity in patients' medical records. The limitations of using financial incentives to stimulate the delivery of counselling in primary care are discussed and a re-appraisal of their use within UK GPs' performance-related pay system is argued for.</p> <p>Summary</p> <p>The utility of targets employed by the system for UK General Practitioners' performance related pay may be inappropriate for encouraging the delivery of health promotion counselling interventions. An evaluation of these targets is essential before they are further developed or added to.</p
Investments in the Human Capital of the Socially Disadvantaged Children – Effects on Redistribution
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