25,855 research outputs found
Inter-reader agreement of high-resolution computed tomography findings in patients with COVID-19 pneumonia: A multi-reader study
Purpose: To investigate the inter-reader agreement in assessing high-resolution computed tomography (HRCT) features of coronavirus disease 2019 (COVID-19) pneumonia. Method: Seventy-seven consecutive patients (mean age, 64 \ub1 15\ua0years) with mild COVID-19 pneumonia that underwent HRCT were retrospectively included. Three radiologists [two devoted to thoracic imaging (R1, R2), and one generalist (R3)] on a per-examination basis independently assessed ground-glass opacity (GGO), consolidation, and crazy-paving pattern. The extent of each feature (total feature score, TFS) was semi-quantitatively assessed, and each TFS summed up to obtain total lung score (TLS). Presence of organizing pneumonia (OP) pattern was also recorded. The inter-reader agreement was calculated with Cohen\u2019s Kappa (k) and Free-Marginal Multirater k. Multivariable analysis was run to determine whether imaging features were predictive of short-term evolution to severe disease (need for ventilation). Results: Most features showed substantial inter-reader agreement, including TLS > 6 (k = 0.69), which was an independent predictor of short-term occurrence of severe disease, regardless of the reader (OR 9\u201353.19). Consolidation TFS > 2 and OP pattern showed substantial and moderate agreement, respectively, only when comparing R1 and R2. Consolidation TFS > 2 and OP pattern were independent predictors of severe disease for R2 (OR 4.87) and R1 (OR 6), respectively. Conclusions: The inter-reader agreement for most HRCT features of COVID-19 pneumonia ranges moderate-to-substantial, though it depends on readers\u2019 experience in the case of consolidation and OP pattern
Delivering reform in English healthcare: an ideational perspective
A variety of perspectives has been put forward to understand reform across healthcare systems. Recently, some have called for these perspectives to give greater recognition to the role of ideational processes. The purpose of this article is to present an ideational approach to understanding the delivery of healthcare reform. It draws on a case of English healthcare reform â the Next Stage Review led by Lord Darzi â to show how the delivery of its reform proposals was associated with four ideational frames. These frames built on the idea of âprogressâ in responding to existing problems; the idea of âprevailing policyâ in forming part of a bricolage of ideas within institutional contexts; the idea of âprescriptionâ as top-down structural change at odds with local contexts; and the idea of âprofessional disputesâ in challenging the notion of clinical engagement across professional groups. The article discusses the implications of these ideas in furthering our understanding of policy change, conflict and continuity across healthcare settings
Investigating white matter fibre density and morphology using fixel-based analysis
Voxel-based analysis of diffusion MRI data is increasingly popular. However, most white matter voxels contain contributions from multiple fibre populations (often referred to as crossing fibres), and therefore voxel-averaged quantitative measures (e.g. fractional anisotropy) are not fibre-specific and have poor interpretability. Using higher-order diffusion models, parameters related to fibre density can be extracted for individual fibre populations within each voxel (âfixelsâ), and recent advances in statistics enable the multi-subject analysis of such data. However, investigating within-voxel microscopic fibre density alone does not account for macroscopic differences in the white matter morphology (e.g. the calibre of a fibre bundle). In this work, we introduce a novel method to investigate the latter, which we call fixel-based morphometry (FBM). To obtain a more complete measure related to the total number of white matter axons, information from both within-voxel microscopic fibre density and macroscopic morphology must be combined. We therefore present the FBM method as an integral piece within a comprehensive fixel-based analysis framework to investigate measures of fibre density, fibre-bundle morphology (cross-section), and a combined measure of fibre density and cross-section. We performed simulations to demonstrate the proposed measures using various transformations of a numerical fibre bundle phantom. Finally, we provide an example of such an analysis by comparing a clinical patient group to a healthy control group, which demonstrates that all three measures provide distinct and complementary information. By capturing information from both sources, the combined fibre density and cross-section measure is likely to be more sensitive to certain pathologies and more directly interpretable
The role of the exit in the initial screening of investment opportunities: The case of business angel syndicate gatekeepers
The exit process has been largely ignored in business angel research.. The practitioner community identifies the difficulty in achieving exits as the most pressing problem for investors. This has been attributed to the failure of investors to adopt an exit-centric approach to investing. The validity of this claim is examined via a study of the investment approach of 21 âgatekeepersâ (managers) of angel groups in Scotland and Northern Ireland. Most gatekeepers say that they do consider the exit when they invest. However, this is contradicted by a verbal protocol analysis which indicates that the exit is not a significant consideration in their initial screening process. The small number of exits achieved by the groups is consistent with the general lack of an exit-centric approach to investing. Only three groups exhibit evidence of a strong exit-centric approach to investing. The lack of exits may have a negative impact on the level of future angel investment activity
Exploration of the Eucalyptus globulus gene pool
The first Europeans to discover Eucalyptus
globulus were French explorers in 1792. Its seed
was rapidly spread throughout the world in the
19th century and this was the species by which
much of the world first knew the genus.
However, it was in the industrial forests of the
20th century that this species, once considered
the âPrince of Eucalyptsâ, achieved greatest
prominence due to its fast growth and superior
pulp qualities. Formal breeding first commenced
in 1966 in Portugal and in the late 1980âs large
base population trials from open-pollinated seed
collections from native stands were established
in many countries. These trials have provided
unprecedented insights into the quantitative
genetic control of numerous traits of economic
and ecological importance and how this variation
is spatially distributed in the native range of the
species. However with large, fully pedigreed
breeding populations becoming available for
quantitative analysis and the rapidly expanding
knowledge of DNA sequence variation, we are
now at the threshold of a new understanding of
this important eucalypt gene pool. Indications of
the significance of non-additive genetic effects
are becoming available. The E. globulus
chloroplast genome has now been sequenced
and several genome maps have been published.
Studies of the variation in nuclear microsatellites
and the lignin biosynthesis gene CCR confirm
the complex, spatially structured nature of the
native gene pool. Strong spatial structuring of
the chloroplast genome has provided a tool for
tracking seed migration and the geographic
origin of exotic landraces. Highly divergent
lineages of chloroplast DNA have been
discovered and studies of the hypervariable JLA+
region argue that some components of the E.
globulus gene pool have been assimilated from
other species following hybridisation
A cross validation of Consumer-Based Brand Equity (CBBE) with Private Labels in Spain
Molinillo,S., Ekinci, Y., Japutra, A. (2014)'A cross validation of Consumer-Based Brand Equity (CBBE) with Private Labels in Spain'. in MartĂnez-LĂłpez, GĂĄzquez-Abad, J.C. and Sethuraman, R. J.A. (eds.) Advances in National Brand and Private Label Marketing. Second International Conference, 2015. Springer Proceedings in Business and Economics, pp. 113-125In recent years a number of Consumer-Based Brand Equity (CBBE) models and measurement scales have been introduced in the branding literature. However, examinations of brand equity in Private Labels (PL) are rather limited. This study aims to compare the validity of the two prominent CBBE models those introduced by Yoo and Donthu (2001) and Nam et al. (2011). In order to test the models and make this comparison, the study collected data from 236 respondents who rated private labels in Spain. A list of 30 different fashion and sportswear PL was introduced to respondents. These brands do not make any reference to the retail store in which they are sold. Research findings suggest that the extended CBBE model introduced by Nam et al. (2011) and Ciftci et al. (2014) is more reliable and valid than Yoo and Donthuâs model for assessing PL. Theoretical contributions and managerial implications are discussed.Universidad de MĂĄlaga. Campus de Excelencia Internacional AndalucĂa Tech
Simultaneous Extraction of the Fermi constant and PMNS matrix elements in the presence of a fourth generation
Several recent studies performed on constraints of a fourth generation of
quarks and leptons suffer from the ad-hoc assumption that 3 x 3 unitarity holds
for the first three generations in the neutrino sector. Only under this
assumption one is able to determine the Fermi constant G_F from the muon
lifetime measurement with the claimed precision of G_F = 1.16637 (1) x 10^-5
GeV^-2. We study how well G_F can be extracted within the framework of four
generations from leptonic and radiative mu and tau decays, as well as from K_l3
decays and leptonic decays of charged pions, and we discuss the role of lepton
universality tests in this context. We emphasize that constraints on a fourth
generation from quark and lepton flavour observables and from electroweak
precision observables can only be obtained in a consistent way if these three
sectors are considered simultaneously. In the combined fit to leptonic and
radiative mu and tau decays, K_l3 decays and leptonic decays of charged pions
we find a p-value of 2.6% for the fourth generation matrix element |U_{e 4}|=0
of the neutrino mixing matrix.Comment: 19 pages, 3 figures with 16 subfigures, references and text added
refering to earlier related work, figures and text in discussion section
added, results and conclusions unchange
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