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Healthcare personnel (HCP) were recruited to provide serum samples, which were tested for antibodies against Ebola or Lassa virus to evaluate for asymptomatic seroconversion.
From 2014 to 2016, 4 patients with Ebola virus disease (EVD) and 1 patient with Lassa fever (LF) were treated in the Serious Communicable Diseases Unit (SCDU) at Emory University Hospital. Strict infection control and clinical biosafety practices were implemented to prevent nosocomial transmission of EVD or LF to HCP.
All personnel who entered the SCDU who were required to measure their temperatures and complete a symptom questionnaire twice daily were eligible.
No employee developed symptomatic EVD or LF. EVD and LF antibody studies were performed on sera samples from 42 HCP. The 6 participants who had received investigational vaccination with a chimpanzee adenovirus type 3 vectored Ebola glycoprotein vaccine had high antibody titers to Ebola glycoprotein, but none had a response to Ebola nucleoprotein or VP40, or a response to LF antigens.
Patients infected with filoviruses and arenaviruses can be managed successfully without causing occupation-related symptomatic or asymptomatic infections. Meticulous attention to infection control and clinical biosafety practices by highly motivated, trained staff is critical to the safe care of patients with an infection from a special pathogen.
We consider the problem of routing and admission control in a loss system featuring two classes of arriving jobs (high-priority and low-priority jobs) and two types of servers, in which decision-making for high-priority jobs is forced, and rewards influence the desirability of each of the four possible routing decisions. We seek a policy that maximizes expected long-run reward, under both the discounted reward and long-run average reward criteria, and formulate the problem as a Markov decision process. When the reward structure favors high-priority jobs, we demonstrate that there exists an optimal monotone switching curve policy with slope of at least −1. When the reward structure favors low-priority jobs, we demonstrate that the value function, in general, lacks structure, which complicates the search for structure in optimal policies. However, we identify conditions under which optimal policies can be characterized in greater detail. We also examine the performance of heuristic policies in a brief numerical study.
This editorial explores the implications of social media practices whereby
people with mental health problems share their experiences in online public
spaces and challenge mental health stigma. Social media enable individuals
to bring personal experience into the public domain with the potential to
affect public attitudes and mainstream media. We draw tentative conclusions
regarding the use of social media by campaigning organisations.
Joseph Addison's 1713 play, Cato: A Tragedy, dramatizes the final days of Cato the Younger's resistance to Julius Caesar before his eventual suicide at Utica in 46 BC. Although Addison initially seems to present Cato as a model for emulation, we argue that Addison is ultimately critical of both Cato and the Stoicism he embodies. Via the play's romantic subplot and via his work as an essayist, Addison offers a revision of the Catonic model, reworking it into a gentler model that elevates qualities such as love, friendship, and sympathy and that is more appropriate to the type of peaceful civil and commercial society he wishes to promote.
In order to optimise care of the adult patients with complex congenital heart disease, there is a need to develop recommendations for interventions. This document is the work of representatives of the three relevant societies and provides recommendations for institutions and operators performing cardiac interventions in these patients.
Parents' use of conventional versus unconventional labels with their two- (n=12), three- (n=12) and four-year-old children (n=12) was assessed as they talked about objects that were either known or unknown to them. For known objects, parents provided typical conventional labels casually during the conversation. For unknown objects, parents were less likely to use typical nouns as labels and marked their labels with additional information suggesting that the labels might be unconventional. Parents marked potentially unconventional labels by providing explicit statements of ignorance and paralinguistic cues of uncertainty. These patterns were strongest when the unknown objects were manufactured as opposed to homemade, possibly because manufactured objects are supposed to have conventional names that parents were unable to provide. Parents' marking of unconventional labels may help children recognize when new word forms should be treated with caution and guide their learning accordingly.
The Women's Health Initiative Memory Study (WHIMS) has been much criticized and it has been suggested that subgroups of women exist for whom hormone therapy (HT) might improve or impair cognitive function. Possible modifying variables could be age, smoking, body mass index, and menopausal symptoms. These were included in artificial neural networks (ANN) analyses, which allow testing of complex non-linear higher order interactions of variables to predict outcomes. Artificial neural networks analyses without hidden units could predict responders and non-responders to treatment as well as logistic regression models that included only main effects, which indicated that higher order interactions were not necessary and did not add to the value of the models. There seemed to be no subgroups (e.g., older women who smoke and have a high body mass) for whom HT has a worse or better effect on cognitive function over time. This study also showed that cross-validation is essential in building robust models with many independent variables and should be applied as a standard technique in complex multivariate analyses.
Bacterial cell biology and pathogenesis
Helen J. Betts, Bacterial Pathogenesis and Genomics Unit, Division of Immunity and Infection, The Institute for Biomedical Research, University of Birmingham, Edgbaston, UK,
Christopher M. Bailey, Bacterial Pathogenesis and Genomics Unit, Division of Immunity and Infection, The Institute for Biomedical Research, University of Birmingham, Edgbaston, UK,
Mark J. Pallen, Bacterial Pathogenesis and Genomics Unit, Division of Immunity and Infection, The Institute for Biomedical Research, University of Birmingham, Edgbaston, UK,
Ian R. Henderson, Bacterial Pathogenesis and Genomics Unit, Division of Immunity and Infection, The Institute for Biomedical Research, University of Birmingham, Edgbaston, UK
To survive in any given niche, bacteria must be capable of sensing, interacting with, and responding to their environment. The method and extent to which bacteria interact with their environment are governed to a large degree by the proteinaceous molecules located on the bacterial cell surface or released into the extracellular milieu. Due to differences in cell-envelope architecture, this process of protein secretion is markedly different between Gram-positive and Gram-negative organisms.
GRAM-POSITIVE VERSUS GRAM-NEGATIVE BACTERIA
Gram-positive bacteria possess a single biological membrane termed the cytoplasmic membrane, which is surrounded by a thick cell wall. The majority of proteins targeted for secretion possess an N-terminal amino-acid signal peptide and utilize the Sec-dependent pathway (Holland, 2004). The Sec machinery is composed of several membrane-associated proteins, including an ATPase (SecA), the Sec translocon (SecYEG), which appears to be the basic unit of cellular life forms, several integral membrane proteins (e.g. SecD, SecF), and a signal peptidase that removes the signal peptide during translocation of the proteins across the cytoplasmic membrane (Dalbey and Chen, 2004). In addition to the Sec pathway, several alternative protein-secretion systems have been recognized in Gram-positive organisms, including the Tat (twin arginine translocation) and ESAT-6/WXG-100 pathways (Pallen, 2002; Robinson and Bolhuis, 2004). However, the role of these systems in protein secretion in Gram-positive bacteria is minor in comparison with the Sec-dependent pathway. Once translocated across the cytoplasmic membrane, the mature protein either can be released into the extracellular milieu or may remain in contact with the cell wall.
An experimental investigation into the structure of a supersonic jet impinging on a large plate is presented. Digital particle image velocimetry (DPIV), shadowgraph photography and acoustic measurements are used to understand the relationship between the unsteady jet structure and the production of tones for nozzle-to-plate spacings between 1 and 5 nozzle exit diameters at a nozzle–pressure ratio equal to 4. Results indicate that the instability of the jet depends on the location of the plate in the shock cell structure of the corresponding free jet and the strength of the standoff shock wave, rather than on the occurrence of recirculation zones in the impingement region. Phase-locked studies show streamwise displacements of the stand-off shock wave, a moving recirculation zone in the subsonic flow in front of the plate, and significant oscillations of both the compression and expansion regions in the peripheral supersonic flow when tones are produced. Sound is shown to be generated by periodic pulsing of the wall jet boundary resulting from periodic motion of the flow in the impingement and near-wall regions of the flow.
Combinatorial and high throughput methods have been utilised in the pharmaceutical industry for many years. The process involves the simultaneous synthesis of libraries containing thousands of compounds, which can then be screened for desirable properties. More recently the concepts of parallel synthesis and high-throughput screening have emerged as effective strategies in the search for novel inorganic materials. We report the development of high throughput methods, which have been used for the synthesis and preliminary characterisation of ceramic oxide pigments on an alumina substrate. This methodology has been utilised to prepare compounds with the spinel structure in the series Cu1-xZnxAl2-yCryO4 (0≤x≤1, 0≤y≤2) at a range of temperatures. The materials are analysed by rapid sequential X-ray diffraction and a simple colour measurement technique. The optical properties across the quaternary landscape can therefore be mapped as a function of composition, structure and annealing temperature.
Simulation-based policy iteration (SBPI) is a modification
of the policy iteration algorithm for computing optimal policies
for Markov decision processes. At each iteration, rather than
solving the average evaluation equations, SBPI employs simulation
to estimate a solution to these equations. For recurrent
average-reward Markov decision processes with finite state and
action spaces, we provide easily verifiable conditions that
ensure that simulation-based policy iteration almost-surely
eventually never leaves the set of optimal decision rules. We
analyze three simulation estimators for solutions to the average
evaluation equations. Using our general results, we derive simple
conditions on the simulation run lengths that guarantee the
almost-sure convergence of the algorithm.
The aim of the study was to evaluate the health of children with cerebral palsy (CP) using a global assessment of quality of life, condition-specific measures, and assessments of health care use. A multicenter population-based cross-sectional survey of 235 children, aged 2 to 18 years, with moderate to severe impairment, was carried out using Gross Motor Function Classification System (GMFCS) levels III (n=56), IV (n=55), and V (n=122). This study group scored significantly below the mean on the Child Health Questionnaire (CHQ) for Pain, General Health, Physical Functioning, and Impact on Parents. These children used more medications than children without CP from a national sample. Fifty-nine children used feeding tubes. Children in GMFCS level V who used a feeding tube had the lowest estimate of mental age, required the most health care resources, used the most medications, had the most respiratory problems, and had the lowest Global Health scores. Children with the most severe motor disability who have feeding tubes are an especially frail group who require numerous health-related resources and treatments. Also, there is a relationship among measures of health status such as the CHQ, functional abilities, use of resources, and mental age, but each appears to measure different aspects of health and well-being and should be used in combination to reflect children's overall health status.
Key features of reproductive behavior in China vary systematically through space and time. In this article we present an analysis of fertility change in regional space, using a 1% household sample from China’s 1990 population census. Elsewhere,we use the same data to analyze reproductive strategizing, but here we pursue the big picture with a straightforward analysis that takes reported births as an uncomplicated indicator of fertility.The article has three objectives: first, to introduce a novel, multilevel spatial model of regional structure constructed using a geographic information system (GIS); second, to demonstrate the potential for longitudinal data derived from onetime censuses to contribute to historical demography in conjunction with regional analysis; and third, to document the manner in which China’s fertility transition has unfolded in regional space.
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