4,494 research outputs found

    The case for the development and use of "ecologically valid" measures of executive function in experimental and clinical neuropsychology

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    This article considers the scientific process whereby new and better clinical tests of executive function might be developed, and what form they might take. We argue that many of the traditional tests of executive function most commonly in use (e.g., the Wisconsin Card Sorting Test; Stroop) are adaptations of procedures that emerged almost coincidentally from conceptual and experimental frameworks far removed from those currently in favour, and that the prolongation of their use has been encouraged by a sustained period of concentration on “construct-driven” experimentation in neuropsychology. This resulted from the special theoretical demands made by the field of executive function, but was not a necessary consequence, and may not even have been a useful one. Whilst useful, these tests may not therefore be optimal for their purpose. We consider as an alternative approach a function-led development programme which in principle could yield tasks better suited to the concerns of the clinician because of the transparency afforded by increased “representativeness” and “generalisability.” We further argue that the requirement of such a programme to represent the interaction between the individual and situational context might also provide useful constraints for purely experimental investigations. We provide an example of such a programme with reference to the Multiple Errands and Six Element tests

    Induced P-wave Superfluidity in Asymmetric Fermi Gases

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    We show that two new intra-species P-wave superfluid phases appear in two-component asymmetric Fermi systems with short-range S-wave interactions. In the BEC limit, phonons of the molecular BEC induce P-wave superfluidity in the excess fermions. In the BCS limit, density fluctuations induce P-wave superfluidity in both the majority and the minority species. These phases may be realized in experiments with spin-polarized Fermi gases.Comment: published versio

    A randomized, blinded, controlled trial investigating the gastrointestinal health effects of drinking water quality.

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    A double-blinded, randomized, controlled trial was carried out in in Melbourne, Australia, to determine the contribution of drinking water to gastroenteritis. Melbourne is one of the few major cities in the world that draws drinking water from a protected forest catchment with minimal water treatment (chlorination only). Six hundred families were randomly allocated to receive either real or sham water treatment units (WTUs) installed in their kitchen. Real units were designed to remove viruses, bacteria, and protozoa. Study participants completed a weekly health diary reporting gastrointestinal symptoms during the 68-week observation period. There were 2,669 cases of highly credible gastroenteritis (HCG) during the study (0.80 cases/person/year). The ratio of HCG episode rates for the real WTU group compared to the sham WTU group was 0.99 (95% confidence interval, 0.85-1.15, p = 0.85). We collected 795 fecal specimens from participants with gastroenteritis, and pathogens were not more significantly common in the sham WTU group. We found no evidence of waterborne disease in Melbourne. The application of this methodology to other water supplies will provide a better understanding of the relationship between human health and water quality

    How pragmatic are the randomised trials used in recommendations for control of glycosylated haemoglobin levels in type 2 diabetic patients in general practice: an application of the PRECIS II tool.

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    BACKGROUND: Recommendations for good clinical practice have been reported to be difficult to apply in real life by primary care clinicians. This could be because the clinical trials at the origin of the guidelines are based on explanatory trials, conducted under ideal conditions not reflecting the reality of primary care, rather than pragmatic trials conducted under real-life conditions. The objective of this study was to evaluate how pragmatic are the clinical trials used to build the French High Authority of Health's recommendations on the management of type II diabetes. METHODS: Trials from the 2013 Cochrane meta-analysis that led to the 2013 French High Authority of Health's recommendations on the management of type II diabetes were selected. Each trial was analysed by applying the PRECIS-2 tool to evaluate whether the trial was pragmatic or explanatory, according to the nine domains of PRECIS-2. Each domain was scored between 1 (very explanatory) and 5 (very pragmatic) by two blinded researchers, and consensus was reached with a third researcher in case of discrepancy. Median scores were calculated for each of the nine domains. RESULTS: Twenty-three articles were analysed. Eight out of nine domains - namely eligibility, recruitment, setting, organisation, flexibility of delivery, flexibility of adherence, follow-up, and primary outcome - had a median score of less than 3, indicating a more explanatory design. Only the primary analysis domain had a score indicating a more pragmatic approach (median score of 4). In more than 25% of the articles, data to score the domains of recruitment, flexibility of delivery, flexibility of adherence, and primary analysis were missing. CONCLUSIONS: Trials used to build French recommendations for good clinical practice for the management of type 2 diabetes in primary care were more explanatory than pragmatic. Policy-makers should encourage the funding of pragmatic trials to evaluate the different strategies proposed for managing the patient's treatment according to HbA1C levels and give clinicians feasible recommendations

    Ellipticals with Kinematically-Distinct Cores: (V-I) Color Images with WFPC2

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    We have analysed HST/WFPC2 F555W and F814W images for fifteen elliptical galaxies with kinematically-distinct cores. For each of them we have derived surface brightness and isophotal parameter profiles in the two bands, color maps, and radial profiles in (V-I). We have detected photometric evidence for faint stellar disks, on scales of a few tens to a few arcseconds, in seven galaxies, namely NGC 1427, 1439, 1700, 4365, 4406, 4494 and 5322. In NGC 1700, the isophotes are slightly boxy at the scale of the counter-rotating component, and disky at larger radii. We find no difference in (V-I) color greater than 0.02 mag between these disks and the surrounding galactic regions. Hence the stellar populations in the kinematically distinct cores are not strongly deviant from the population of the main body. For one galaxy, NGC 4365, the innermost region is bluer than the surrounding regions. This area extends to about 15pc, and contains a luminosity of 2.5x10^6 L_\odot. If interpreted as a stellar population effect, an age difference of \sim 3-4 Gyrs, or an [Fe/H][Fe/H] variation of about 0.2 dex, is derived. The nuclear intensity profiles show a large variety: some galaxies have steep cusp profiles, others have shallow cusps and a ``break radius''. The nuclear cusps of galaxies with kinematically-distinct cores follow the same trends as the nuclei of normal galaxies. We have not been able to identify a unique, qualifying feature in the WFPC2 images which distinguish the galaxies with kinematically distinct cores from the kinematically normal cores. [shortened]Comment: 56 pages, latex, 17 figures; figure 1 available upon request; ApJ, 481 in pres

    Probing Spectral Line Gradients Beyond One Effective Radius in NGC 3610

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    The outer region (0.75--1.25 r_e in the B-band) of the merger-remnant elliptical NGC 3610 is studied using extremely high signal to noise Keck spectra, with a supplementary spectrum of the galaxy center. Stellar population parameters -- age, [Z/H], [α\alpha/Fe] -- are measured in several apertures along the slit. Using the multi-index simultaneous fitting method of Proctor et al. (2004), no significant stellar population gradients are detected in the outer parts of the galaxy. The overall gradients relative to the galaxy center are consistent with those found in many other early-type galaxies, though the metallicity gradient is much steeper than would be expected if NGC 3610 formed in a major merger event. Standard analysis methods using the Hβ\beta index are found to produce spurious radially variable gradients.Comment: 15 pages, 9 figures, accepted by A

    Moyal star product approach to the Bohr-Sommerfeld approximation

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    The Bohr-Sommerfeld approximation to the eigenvalues of a one-dimensional quantum Hamiltonian is derived through order 2\hbar^2 (i.e., including the first correction term beyond the usual result) by means of the Moyal star product. The Hamiltonian need only have a Weyl transform (or symbol) that is a power series in \hbar, starting with 0\hbar^0, with a generic fixed point in phase space. The Hamiltonian is not restricted to the kinetic-plus-potential form. The method involves transforming the Hamiltonian to a normal form, in which it becomes a function of the harmonic oscillator Hamiltonian. Diagrammatic and other techniques with potential applications to other normal form problems are presented for manipulating higher order terms in the Moyal series.Comment: 27 pages, no figure

    Source attribution, prevalence and enumeration of Campylobacter spp. from retail liver

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    Funding Information: We thank Food Standards Agency, Scotland for funding this work.Peer reviewedPreprin

    Minimax Current Density Coil Design

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    'Coil design' is an inverse problem in which arrangements of wire are designed to generate a prescribed magnetic field when energized with electric current. The design of gradient and shim coils for magnetic resonance imaging (MRI) are important examples of coil design. The magnetic fields that these coils generate are usually required to be both strong and accurate. Other electromagnetic properties of the coils, such as inductance, may be considered in the design process, which becomes an optimization problem. The maximum current density is additionally optimized in this work and the resultant coils are investigated for performance and practicality. Coils with minimax current density were found to exhibit maximally spread wires and may help disperse localized regions of Joule heating. They also produce the highest possible magnetic field strength per unit current for any given surface and wire size. Three different flavours of boundary element method that employ different basis functions (triangular elements with uniform current, cylindrical elements with sinusoidal current and conic section elements with sinusoidal-uniform current) were used with this approach to illustrate its generality.Comment: 24 pages, 6 figures, 2 tables. To appear in Journal of Physics D: Applied Physic
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