Exploring fatigue as a social construct:implications for work hour reform in postgraduate medical education

This thesis seeks to understand what motivates residents’ decisions around managing fatigue both within and beyond the workplace learning environment. Using a constructivist grounded theory approach to qualitative research; fatigue is introduced as a social construct, beyond a strictly physical or emotional experience. Results suggest that fatigue in medical education is constructed as a personal challenge to be overcome, rather than an occupational safety hazard as in the aviation industry. The implications of this social construct are considered alongside existing proposed solutions to the problem of trainee fatigue, including work hour reform and fatigue management plans

Three-body halos. V. Computations of continuum spectra for Borromean nuclei

We solve the coordinate space Faddeev equations in the continuum. We employ hyperspherical coordinates and provide analytical expressions allowing easy computation of the effective potentials at distances much larger than the ranges of the interactions where only s-waves in the different Jacobi coordinates couple. Realistic computations are carried out for the Borromean halo nuclei 6He (n+n+\alpha) for J\pi = 0+-, 1+-, 2+- and 11Li (n+n+9Li) for (1/2)+-, (3/2)+-, (5/2)+-. Ground state properties, strength functions, Coulomb dissociation cross sections, phase shifts, complex S-matrix poles are computed and compared to available experimental data. We find enhancements of the strength functions at low energies and a number of low-lying S-matrix poles.Comment: 35 pages, 14 figure

Toeplitz operators on symplectic manifolds

We study the Berezin-Toeplitz quantization on symplectic manifolds making use of the full off-diagonal asymptotic expansion of the Bergman kernel. We give also a characterization of Toeplitz operators in terms of their asymptotic expansion. The semi-classical limit properties of the Berezin-Toeplitz quantization for non-compact manifolds and orbifolds are also established.Comment: 40 page

Non-perturbative Propagators, Running Coupling and Dynamical Quark Mass of Landau gauge QCD

The coupled system of renormalized Dyson-Schwinger equations for the quark, gluon and ghost propagators of Landau gauge QCD is solved within truncation schemes. These employ bare as well as non-perturbative ansaetze for the vertices such that the running coupling as well as the quark mass function are independent of the renormalization point. The one-loop anomalous dimensions of all propagators are reproduced. Dynamical chiral symmetry breaking is found, the dynamically generated quark mass agrees well with phenomenological values and corresponding results from lattice calculations. The effects of unquenching the system are small. In particular the infrared behavior of the ghost and gluon dressing functions found in previous studies is almost unchanged as long as the number of light flavors is smaller than four.Comment: 34 pages, 10 figures, version to be published by Phys. Rev.

Bouncing and Accelerating Solutions in Nonlocal Stringy Models

A general class of cosmological models driven by a non-local scalar field inspired by string field theories is studied. In particular cases the scalar field is a string dilaton or a string tachyon. A distinguished feature of these models is a crossing of the phantom divide. We reveal the nature of this phenomena showing that it is caused by an equivalence of the initial non-local model to a model with an infinite number of local fields some of which are ghosts. Deformations of the model that admit exact solutions are constructed. These deformations contain locking potentials that stabilize solutions. Bouncing and accelerating solutions are presented.Comment: Minor corrections, references added, published in JHE

Risk of a first clinical diagnosis of central nervous system demyelination in relation to human herpesviruses in the context of Epstein–Barr virus

OnlinePublBackground and purpose: Epstein–Barr virus (EBV) is implicated in multiple sclerosis (MS) risk; evidence for other herpesviruses is inconsistent. Here, we test blood markers of infection with human herpesvirus 6 (HHV-6), varicella zoster virus (VZV), and cytomegalovirus (CMV) as risk factors for a first clinical diagnosis of central nervous system demyelination (FCD) in the context of markers of EBV infection. Methods: In the Ausimmune case–control study, cases had an FCD, and population controls were matched on age, sex, and study region. We quantified HHV-6- and VZVDNA load in whole blood and HHV-6, VZV, and CMV antibodies in serum. Conditional logistic regression tested associations with FCD risk, adjusting for Epstein–Barr nuclear antigen (EBNA) IgG, EBV-DNA load, and other covariates. Results: In 204 FCD cases and 215 matched controls, only HHV-6-DNA load (positive vs. negative) was associated with FCD risk (adjusted odds ratio = 2.20, 95% confidence interval = 1.08–4.46, p= 0.03). Only EBNA IgG and HHV-6-DNA positivity were retained in a predictive model of FCD risk; the combination had a stronger association than either alone. CMV-specific IgG concentration modified the association between an MS riskrelated human leucocyte antigen gene and FCD risk. Six cases and one control had very high HHV-6-DNA load (>1.0 × 106 copies/mL). Conclusions: HHV-6-DNA positivity and high load (possibly due to inherited HHV-6 chromosomal integration) were associated with increased FCD risk, particularly in association with markers of EBV infection. With growing interest in prevention/ management of MS through EBV-related pathways, there should be additional consideration of the role of HHV-6 infection.Robyn M. Lucas, Meav-Lang J. Lay, James Grant, Nicolas Cherbuin, Cheryl S. Toi, Keith Dear, Bruce V. Taylor, Dominic E. Dwyer, Ausimmune Investigator Group, Anne-Louise Ponsonb

A pro-inflammatory diet in people with multiple sclerosis is associated with an increased rate of relapse and increased FLAIR lesion volume on MRI in early multiple sclerosis: A prospective cohort study

First published online May 6, 2023Background: A pro-inflammatory diet has been posited to induce chronic inflammation within the central nervous system (CNS), and multiple sclerosis (MS) is an inflammatory disease of the CNS. Objective: We examined whether Dietary Inflammatory Index (DII®)) scores are associated with measures of MS progression and inflammatory activity. Methods: A cohort with a first clinical diagnosis of CNS demyelination was followed annually (10 years, n=223). At baseline, 5- and 10-year reviews, DII and energy-adjusted DII (E-DIITM) scores were calculated (food frequency questionnaire) and assessed as predictors of relapses, annualised change in disability (Expanded Disability Status Scale) and two magnetic resonance imaging measures; fluid-attenuated inversion recovery (FLAIR) lesion volume and black hole lesion volume. Results: A more pro-inflammatory diet was associated with a higher relapse risk (highest vs. lowest E-DII quartile: hazard ratio=2.24, 95% confidence interval (CI)= −1.16, 4.33, p=0.02). When we limited analyses to those assessed on the same manufacturer of scanner and those with a first demyelinating event at study entry (to reduce error and disease heterogeneity), an association between E-DII score and FLAIR lesion volume was evident (β=0.38, 95% CI=0.04, 0.72, p=0.03). Conclusion: There is a longitudinal association between a higher DII and a worsening in relapse rate and periventricular FLAIR lesion volume in people with MS.Alice M Saul, Bruce V Taylor, Leigh Blizzard, Steve Simpson-Yap, Wendy H Oddy, Nittin Shivappa, James R Hébert, Lucinda J Black, Anne-Louise Ponsonby, Simon A Broadley, Jeanette Lechner-Scott and Ingrid van der Mei, Ausimmune, AusLong Investigators Grou

Photochemically produced SO2 in the atmosphere of WASP-39b

S.-M.T. is supported by the European Research Council advanced grant EXOCONDENSE (no. 740963; principal investigator: R. T. Pierrehumbert). E.K.H.L. is supported by the SNSF Ambizione Fellowship grant (no. 193448). X.Z. is supported by NASA Exoplanet Research grant 80NSSC22K0236. O.V. acknowledges funding from the ANR project ‘EXACT’ (ANR-21-CE49-0008-01), from the Centre National d’Études Spatiales (CNES) and from the CNRS/INSU Programme National de Planétologie (PNP). L.D. acknowledges support from the European Union H2020-MSCA-ITN-2109 under grant no. 860470 (CHAMELEON) and the KU Leuven IDN/19/028 grant Escher. This work benefited from the 2022 Exoplanet Summer Program at the Other Worlds Laboratory (OWL) at the University of California, Santa Cruz, a programme financed by the Heising-Simons Foundation. T.D. is an LSSTC Catalyst Fellow. J.K. is an Imperial College Research Fellow. B.V.R. is a 51 Pegasi b Fellow. L.W. is an NHFP Sagan Fellow. A.D.F. is an NSF Graduate Research Fellow.Photochemistry is a fundamental process of planetary atmospheres that regulates the atmospheric composition and stability1. However, no unambiguous photochemical products have been detected in exoplanet atmospheres so far. Recent observations from the JWST Transiting Exoplanet Community Early Release Science Program2,3 found a spectral absorption feature at 4.05 μm arising from sulfur dioxide (SO2) in the atmosphere of WASP-39b. WASP-39b is a 1.27-Jupiter-radii, Saturn-mass (0.28 MJ) gas giant exoplanet orbiting a Sun-like star with an equilibrium temperature of around 1,100 K (ref. 4). The most plausible way of generating SO2 in such an atmosphere is through photochemical processes5,6. Here we show that the SO2 distribution computed by a suite of photochemical models robustly explains the 4.05-μm spectral feature identified by JWST transmission observations7 with NIRSpec PRISM (2.7σ)8 and G395H (4.5σ)9. SO2 is produced by successive oxidation of sulfur radicals freed when hydrogen sulfide (H2S) is destroyed. The sensitivity of the SO2 feature to the enrichment of the atmosphere by heavy elements (metallicity) suggests that it can be used as a tracer of atmospheric properties, with WASP-39b exhibiting an inferred metallicity of about 10× solar. We further point out that SO2 also shows observable features at ultraviolet and thermal infrared wavelengths not available from the existing observations.Publisher PDFPeer reviewe