119 research outputs found

    A longitudinal study of migration propensities for mixed-ethnic unions in England and Wales

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    This research was funded by the ESRC under the Understanding Population Trends and Processes (UPTAP) programme (Award Ref: RES-163-25-0045).Most studies investigating residential segregation of ethnic minorities ignore the fact that the majority of adults live in couples. In recent years there has been a growth in the number of mixed-ethnic unions that involve a minority member and a white member. To our knowledge, hardly any research has been undertaken to explicitly examine whether the ethnic mix within households has an impact on the residential mobility of households in terms of the ethnic mix of destination neighbourhoods. Our study addresses this research gap and examines the tendencies of mobility among mixed-ethnic unions in comparison with their co-ethnic peers. We used data from the Longitudinal Study for England and Wales. Our statistical analysis supports the spatial assimilation theory; ethnic minorities move towards less deprived areas and to a lesser extent also towards less ethnically concentrated areas. However, the types of destination neighbourhood of minority people living in mixed-ethnic unions varied greatly with the ethnicity of the ethnic minority partner.PostprintPeer reviewe

    D*-->Dpi and D*-->Dgamma decays: Axial coupling and Magnetic moment of D* meson

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    The axial coupling and the magnetic moment of D*-meson or, more specifically, the couplings g(D*Dpi) and g(D*Dgamma), encode the non-perturbative QCD effects describing the decays D*-->Dpi and D*-->Dgamma. We compute these quantities by means of lattice QCD with Nf=2 dynamical quarks, by employing the Wilson ("clover") action. On our finer lattice (a=0.065 fm) we obtain: g(D*Dpi)=20 +/- 2, and g(D0*D0gamma)=[2.0 +/- 0.6]/GeV. This is the first determination of g(D0*D0gamma) on the lattice. We also provide a short phenomenological discussion and the comparison of our result with experiment and with the results quoted in the literature.Comment: 22 pages, 3 figure

    A CHIME/FRB Study of Burst Rate and Morphological Evolution of the Periodically Repeating FRB 20180916B

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    FRB 20180916B is a repeating fast radio burst (FRB) with a 16.3 day periodicity in its activity. In this study, we present morphological properties of 60 FRB 20180916B bursts detected by CHIME/FRB between 2018 August and 2021 December. We recorded raw voltage data for 45 of these bursts, enabling microseconds time resolution in some cases. We studied variation of spectro-temporal properties with time and activity phase. We find that the variation in dispersion measure (DM) is ≲1 pc cm−3 and that there is burst-to-burst variation in scattering time estimates ranging from ∼0.16 to over 2 ms, with no discernible trend with activity phase for either property. Furthermore, we find no DM and scattering variability corresponding to the recent change in rotation measure from the source, which has implications for the immediate environment of the source. We find that FRB 20180916B has thus far shown no epochs of heightened activity as have been seen in other active repeaters by CHIME/FRB, with its burst count consistent with originating from a Poissonian process. We also observe no change in the value of the activity period over the duration of our observations and set a 1σ upper limit of 1.5 × 10−4 day day−1 on the absolute period derivative. Finally, we discuss constraints on progenitor models yielded by our results, noting that our upper limits on changes in scattering and DM as a function of phase do not support models invoking a massive binary companion star as the origin of the 16.3 day periodicity.</p

    Form factors in lattice QCD

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    Lattice simulations of QCD have produced precise estimates for the masses of the lowest-lying hadrons which show excellent agreement with experiment. By contrast, lattice results for the vector and axial vector form factors of the nucleon show significant deviations from their experimental determination. We present results from our ongoing project to compute a variety of form factors with control over all systematic uncertainties. In the case of the pion electromagnetic form factor we employ partially twisted boundary conditions to extract the pion charge radius directly from the linear slope of the form factor near vanishing momentum transfer. In the nucleon sector we focus specifically on the possible contamination from contributions of higher excited states. We argue that summed correlation functions offer the possibility of eliminating this source of systematic error. As an illustration of the method we discuss our results for the axial charge, gA, of the nucleon.Comment: 16 pages, 11 figures, presented at Conclusive Symposium, CRC443, "Many-body structure of strongly interacting systems", 23-25 Feb 2011, Mainz, German

    Exploration of the equilibrium operating space for NSTX-Upgrade

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    This paper explores a range of high-performance equilibrium scenarios available in the NSTX-Upgrade device [J.E. Menard, submitted for publication to Nuclear Fusion]. NSTX-Upgrade is a substantial upgrade to the existing NSTX device [M. Ono, et al., Nuclear Fusion 40, 557 (2000)], with significantly higher toroidal field and solenoid capabilities, and three additional neutral beam sources with significantly larger current drive efficiency. Equilibria are computed with freeboundary TRANSP, allowing a self consistent calculation of the non-inductive current drive sources, the plasma equilibrium, and poloidal field coil current, using the realistic device geometry. The thermal profiles are taken from a variety of existing NSTX discharges, and different assumptions for the thermal confinement scalings are utilized. The no-wall and idealwall n=1 stability limits are computed with the DCON code. The central and minimum safety factors are quite sensitive to many parameters: they generally increases with large outer plasmawall gaps and higher density, but can have either trend with the confinement enhancement factor. In scenarios with strong central beam current drive, the inclusion of non-classical fast ion diffusion raises qmin, decreases the pressure peaking, and generally improves the global stability, at the expense of a reduction in the non-inductive current drive fraction; cases with less beam current drive are largely insensitive to additional fast ion diffusion. The non-inductive current level is quite sensitive to the underlying confinement and profile assumptions. For instance, for BT=1.0 T and Pinj=12.6 MW, the non-inductive current level varies from 875 kA with ITER-98y,2 thermal confinement scaling and narrow thermal profiles to 1325 kA for an ST specific scaling expression and broad profiles. This sensitivity should facilitate the determination of the correct scaling of transport with current and field to use for future fully non-inductive ST devices. Scenarios are presented which can be sustained for 8-10 seconds, or (20-30)τCR, at βN=3.8-4.5, facilitating, for instance, the study of disruption avoidance for very long pulse. Scenarios have been documented which can operate with βT~25% and equilibrated qmin&gt;1. The value of qmin can be controlled at either fixed non-inductive fraction of 100% or fixed plasma current, by varying which beam sources are used, opening the possibility for feedback qmin control. In terms of quantities like collisionality, neutron emission, non-inductive fraction, or stored energy, these scenarios represent a significant performance extension compared to NSTX and other present spherical torii

    Whole-genome sequencing reveals host factors underlying critical COVID-19

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    Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease

    PHASE TRANSFORMATIONS ON ANNEALING OF NON-CRYSTALLINE FERROUS HALIDES

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    Des échantillons non cristallins de FeF2, FeCl2 et FeBr2 obtenus par condensation de vapeurs à basse température, ont été convertis en phase cristalline par recuit à des températures allant jusqu'à 800 K. On trouve que FeCl2 et FeBr2 ne se convertissent jamais directement de l'état non cristallin en l'état cristallin habituel. Ils forment entre 60 et 350 K une phase intermédiaire inconnue. Par contre, FeF2 se convertit directement. Ceci a lieu à des températures beaucoup plus élevées (~ 800 K). L'existence d'une phase intermédiaire pour FeCl2 et FeBr2 mais non pour FeF2, est discutée en fonction des différents changements structuraux ayant lieu lors du processus de recristallisation des dihalogénures de fer non cristallins.Non-crystalline samples of FeF2, FeCl2 and FeBr2 obtained from vapour deposition at low temperatures were converted into the crystalline phase by annealing with temperatures up to 800 K. It is found that FeCl2 and FeBr2 never convert directly from the non-crystalline to the usual crystalline state. They form an unknown intermediate phase in the temperature range between 60 and 350 K. In contrast, FeF2 shows direct conversion. This occurs at much higher temperatures (~ 800 K). The existence of an intermediate phase for FeCl2 and FeBr2, but not for FeF2, is discussed in terms of the different structural changes taking place in the recrystallization processes of the non-crystalline iron di-halides

    Cognitive performance in orthostatic hypotension:Findings from a nationally representative sample

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    Objectives To compare the cognitive profile of a population representative sample with orthostatic hypotension (OH) with the profile of a sample without. Design Cross-sectional analysis of a prospective nationally representative population study. Setting The Irish Longitudinal Study on Ageing (TILDA). Participants TILDA participants (N = 5,936; mean age 63 ± 9, 54% female). Measurements OH was defined as a drop of 20 mmHg or more in systolic blood pressure or of 10 mmHg or more in diastolic blood pressure on standing from a seated position. Cognitive performance was assessed using comprehensive cognitive tests measuring domains of global function, executive function, processing speed, attention, and memory, from which composite standardized scores were computed. Multivariate analysis controlling for potential confounders was performed to compare cognitive performance according to OH status. Results Prevalence of OH was 6.1% (95% confidence interval = 5.4-6.7%). A significant negative association between OH status and global cognitive function (β = -0.21, P =.01) and memory (β = -0.26, P =.002) was found in women aged 65 and older after adjustment for demographic characteristics, mental health, cardiovascular disease, and medications (antihypertensive and antipsychotic), but other specific cognitive domains were not affected. Conclusion OH was associated with poorer global cognitive function and poorer memory, independent of potential confounders, in women in a large population-based sample of older adults. Longitudinal studies with concomitant assessment of cerebral perfusion are needed to determine causal relationships
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