2,343 research outputs found

    Comparative Genomics Analysis Demonstrated a Link Between Staphylococci Isolated From Different Sources: A Possible Public Health Risk

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    Coagulase-negative staphylococci (CoNS) have been recovered from different ecological niches, however, little is known about the genetic relatedness of these isolates. In this study, we used whole genome sequencing to compare mecA positive (mecA⁺) Staphylococcus epidermidis, Staphylococcus haemolyticus and Staphylococcus hominis isolates recovered from hand-touched surfaces from general public settings in East and West London with data of isolates deposited to European Nucleotide Archive (ENA) by other research groups. These included isolates associated with hospital settings (including those recovered from patients), healthy humans, livestock, pets, plants and natural, and other public environments. Using core and accessory phylogenetic analyses we were able to identify that the mecA⁺ S. epidermidis and S. haemolyticus isolates recovered from general public settings were genetically related to isolates recovered from the bloodstream, urinary tract and eye infections. S. epidermidis isolates recovered in our study were also shown to be genetically related to isolates previously recovered from livestock/livestock housing, whereas S. haemolyticus isolates were genetically related to isolates recovered from a dog and kefir (fermented cow milk drink). MecA⁺ S. hominis isolates were not genetically related to any isolates recovered from clinical samples but were genetically related to isolates recovered from mosquitoes, air samples (residential areas) and kefir. All three species showed to have genetic relatedness to isolates recovered from healthy humans. These results show that CoNS isolates in this study share genetic similarities with those of different lineages and that mecA⁺ S. epidermidis and S. haemolyticus isolates found in general public settings in this study may pose a risk to public health

    AI Extenders

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    Humans and AI systems are usually portrayed as separate sys- tems that we need to align in values and goals. However, there is a great deal of AI technology found in non-autonomous systems that are used as cognitive tools by humans. Under the extended mind thesis, the functional contributions of these tools become as essential to our cognition as our brains. But AI can take cognitive extension towards totally new capabil- ities, posing new philosophical, ethical and technical chal- lenges. To analyse these challenges better, we define and place AI extenders in a continuum between fully-externalized systems, loosely coupled with humans, and fully-internalized processes, with operations ultimately performed by the brain, making the tool redundant. We dissect the landscape of cog- nitive capabilities that can foreseeably be extended by AI and examine their ethical implications. We suggest that cognitive extenders using AI be treated as distinct from other cognitive enhancers by all relevant stakeholders, including developers, policy makers, and human users.Leverhulme Centre for the Future of Intelligence, Leverhulme Trust, under Grant RC-2015-06

    Analyzing Engagement Effects for Repatriate Retention

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    Due to the nature of globalization and increased competition levels more and more companies send their employees abroad to gain experience and knowledge. However, at some point, these companies need to repatriate their employees and bring them back into the fold. Currently there exists a very high turnover rate for repatriates and the loss of the knowledge and experience gained is a serious setback for an organization. Further research in examining the antecedents of turnover intention with the aim of reducing this behavior is needed to enhance future competitive capabilities. The main goal of this paper is to set the stage for an empirical analysis of factors that may lead to an increase in turnover intention for both general and repatriated employees. The implications suggest that further research into turnover intention for repatriates could lead to a better understanding of strategic planning in terms of human resources and ease the transition of repatriates back into their organizations

    An approximate method for solving rarefied and transitional flows using TDEFM with isotropic mesh adaptation

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    DSMC [1] can become increasingly expensive when extended to the near-continuum regime. Because of the statistical nature of the results, long run times are required to build up samples of simulator particles large enough to reduce the statistical scatter to acceptable levels. Here we adapt a kinetic theory based flux method to produce a quick approximate solver for transition and near-continuum flows. The results have no statistical scatter. The CPU times are similar to those of traditional continuum (Navier-Stokes or Euler) solvers. The True Direction Equilibrium Flux Method (TDEFM) [2, 3] is a generalisation of Pullin's kinetic theory based EFM [4]. TDEFM can transfer fluxes of mass, momentum and energy in physically realistic directions from any source cell to any destination cell, even if the cells do not share an interface. TDEFM, as an Euler solver, has been shown to provide good results on a Cartesian grid for flows where standard continuum methods produce unphysical asymmetries apparently because the continuum fluxes are constrained (in one time step) to flow in the grid coordinate directions rather than the correct physical direction. [2, 3] The new method for rarefied flow does not try to produce the correct velocity distribution function, but does ensure that mass, momentum and energy are transported within the flow over the physically correct distances between “pseudo-collisions.” To ensure this, (1) the time step is restricted so that mass, momentum and energy are exchanged between contiguous cells only in one time step, and (2) the cells sizes are adapted, as steady state is approached, to be approximately equal to the local mean free path. The results for Mach 5 flow over a flat plate for varying Knudsen numbers show an average difference (compared to DSMC) in the X-velocity profile near the surface of the plate of less than 6 percent. TDEFM, employing adaptive mesh refinement, required less than 9 percent of the computational time required by DSMC for the same flow. Thus the approximate method could be useful for quick “first-estimate” solutions of otherwise time consuming design problems. ©2009 American Institute of Physic

    Mycobacterium tuberculosis Transmission between Cluster Members with Similar Fingerprint Patterns

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    Molecular epidemiologic studies provide evidence of transmission of Mycobacterium tuberculosis within clusters of patients whose isolates share identical IS6110-DNA fingerprint patterns. However, M. tuberculosis transmission among patients whose isolates have similar but not identical DNA fingerprint patterns (i.e., differing by a single band) has not been well documented. We used DNA fingerprinting, combined with conventional epidemiology, to show unsuspected patterns of tuberculosis transmission associated with three public bars in the same city. Among clustered TB cases, DNA fingerprinting analysis of isolates with similar and identical fingerprints helped us discover epidemiologic links missed during routine tuberculosis contact investigations

    Hemodynamic Profiles Before and After Surgery in Bicuspid Aortic Valve Disease—A Systematic Review of the Literature

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    Bicuspid aortic valve (BAV) disease presents a unique management challenge both pre- and post-operatively. 4D flow MRI offers multiple tools for the assessment of the thoracic aorta in aortic valve disease. In particular, its assessment of flow patterns and wall shear stress have led to new understandings around the mechanisms of aneurysm development in BAV disease. Novel parameters have now been developed that have the potential to predict pathological aortic dilatation and may help to risk stratify BAV patients in future. This systematic review analyses the current 4D flow MRI literature after aortic valve and/or ascending aortic replacement in bicuspid aortic valve disease. 4D flow MRI has also identified distinct challenges posed by this cohort at the time of valve replacement compared to standard management of tri-leaflet disorders, and may help tailor the type and timing of replacement. Eccentric pathological flow patterns seen after bioprosthetic valve implantation, but not with mechanical prostheses, might be an important future consideration in intervention planning. 4D flow MRI also has promising potential in supporting the development of artificial valve prostheses and aortic conduits with more physiological flow patterns

    The utility of Ki-67 as a prognostic biomarker in pulmonary neuroendocrine tumours: protocol for a systematic review and meta-analysis

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    INTRODUCTION: The omission of the immunohistochemical proliferation marker Ki-67 labelling index (henceforth, simply Ki-67) from the 2015 WHO classification system of pulmonary neuroendocrine tumours (Lung-NETs) as a prognostic and grading criterion remains controversial. This systematic review along with meta-analysis will be conducted to assess the prognostic/grading utility of Ki-67 in Lung-NETs.METHODS: This systematic review will be conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. A systematic search of MEDLINE Ovid, Embase, Scopus and the Cochrane Library will be performed from the inception of each database to 28 February 2019 for studies investigating any role of Ki-67 in Lung-NETs. Only full papers published in English detailing survival outcomes and HRs according to Ki-67 will be included. The primary endpoint will be establishing whether Ki-67 is a reliable marker in determining prognosis and thus assessing grade of Lung-NETs patients.ETHICS AND DISSEMINATION: Ethical approval will not be required as this is an academic review of published literature. Findings will be disseminated through the preparation of a manuscript for publication in a peer-reviewed journal as well as presentation at national and international conferences.PROSPERO REGISTRATION NUMBER: CRD42018093389.</p
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