4,824 research outputs found
Reference invasive tests of microvascular injury in myocardial infarction
No abstract available
Causes of Mode Effects: Separating out Interviewer and Stimulus Effects in Comparisons of Face-to-Face and Telephone Surveys
We identify the causes of mode effects in comparisons of face-to-face and telephone surveys, by testing for differences in the extent of satisficing and social desirability bias due to differences in the stimulus (visual vs. aural presentation of response options) and the presence vs. absence of the interviewer. The stimulus did not lead to differential measurement error; the presence or absence of the interviewer however did. Telephone respondents were far more likely to give socially desirable responses than face-to-face respondents when the stimulus was the same for both modes
Local heat flux and energy loss in a 2D vibrated granular gas
We performed event-driven simulations of a two-dimensional granular gas
between two vibrating walls and directly measured the local heat flux and
energy dissipation rate in the stationary state. Describing the local heat flux
as a function of the coordinate x in the direction perpendicular to the driving
walls, we use a generalization of Fourier's law, q_x(x) = kappa d_x T(x) + mu
d_x rho(x), to relate the local heat flux to the local gradients of the
temperature and density. This ansatz accounts for the fact that density
gradients also generate heat flux, not only temperature gradients. The
transport coefficients kappa and mu are assumed to be independent of x, and we
check the validity of this assumption in the simulations. Both kappa and mu are
determined for different system parameters, in particular, for a wide range of
coefficients of restitution. We also compare our numerical results to existing
hydrodynamic theories. Agreement is found for kappa for very small
inelasticities only. Beyond this region, kappa and mu exhibit a striking
non-monotonic behavior.Comment: 8 pages, 5 figure
Synthesis of IFN-β by Virus-Infected Chicken Embryo Cells Demonstrated with Specific Antisera and a New Bioassay
Transcripts of interferon-α(IFN-α) and IFN-β genes are present in virus-infected chicken cells, but because
of a lack of appropriate assays and reagents, it was unclear if biologically active IFN-β is secreted. We have
established a nonviral bioassay for the sensitive detection of chicken IFN (ChIFN). This assay is based on a
quail cell line that carries a luciferase gene that is controlled by the IFN-responsive chicken Mx promoter.
Luciferase activity was strongly stimulated when the indicator cells were incubated with ChIFN-α, ChIFN-β,
or ChIFN-γ but not with chicken interleukin-1β (ChIL-1β). Unlike the classic antiviral assay that preferentially
detects ChIFN-α, the Mx-luciferase assay detected ChIFN-α and ChIFN-β with similar sensitivity.
With the help of this novel assay and with rabbit antisera specific for either IFN-α or IFN-β, we analyzed
the composition of IFN in supernatants of virus-infected chicken embryo cells. Virtually all IFN produced in
response to Newcastle disease virus (NDV) was IFN-α. However, IFN produced in response to influenza A or
vaccinia virus (VV) was a mixture of usually more than 80% IFN-α and up to 20% IFN-β. Thus, IFN-α and
IFN-β both contribute to the cytokine activity in supernatants of virus-infected chicken cells. Furthermore,
the infecting virus appears to determine the IFN subtype composition
Truncated Chicken Interleukin-1β with Increased Biologic Activity
Chicken interleukin-1β (ChIL-1β) is synthesized as a precursor molecule that unlike its mammalian counterpart, lacks a typical caspase-1 cleavage site. Therefore, it was unclear if proteolytic cleavage of ChIL-1β can occur and if cleavage might modulate the biologic activity of this cytokine. Using an avian indicator cell line that carries an NF-κB-regulated luciferase reporter gene, we established a sensitive and highly specific bioassay for ChIL-1β. Experiments with a rabbit antiserum indicated that the NF-κB-stimulating activity in supernatants of lipopolysaccharide (LPS)-treated chicken HD-11 macrophages is largely due to IL-1β and that proteolytic processing of natural and recombinant ChIL-1β is not very efficient. Functional analyses further revealed that cDNAs for either full-length or N-terminally truncated chicken ChIL-1β yielded active cytokine. A truncated molecule that closely resembled putative mature ChIL-1β exhibited more than 100-fold enhanced biologic activity after expression in mammalian cells, indicating that precursor cleavage is indeed of critical importance for maximal activity
Validation of Survey Data on Income and Employment: The ISMIE Experience
This report derives from the project "Improving survey measurement of income and employment (ISMIE)" which investigates measurement error in survey data on income and employment, using a UK sub-sample of the European Household Community Panel (ECHP). In this paper we describe the process of collecting validation data and the outcomes of the process. Validation data were obtained from two sources: employers' records and government benefit data from the Department for Work and Pensions (DWP). The former provided information on occupation and employment status, gross and net pay, membership of company pension schemes and industry sector. The latter provided histories of benefit receipt and tax credits, for example, child, disability, housing and unemployment benefits, pensions and income support. In the survey interview, respondents were asked for written permission both to obtain their DWP records and to contact their employer. They were also asked to provide information that would facilitate the process of obtaining the validation data: National Insurance number (NINO) and employer contact details. Subsequently, DWP records were extracted using a non-hierarchical matching strategy, based on different combinations of identifying variables obtained in the survey (NINO, sex, date of birth, name and postcode), and a survey of employers was carried out (mail, with telephone follow-up). The representativeness of the validation samples obtained depends on the co-operation of both survey respondents and providers of validation data, as well as errors in the matching process. We report permission rates, proportions providing matching items, match rates for the DWP data and response rates to the employer survey. We identify correlates of these measures of success at each stage of the validation process in terms of substantive characteristics of the survey respondents. Variation by subgroups is identified and implications for the representativeness of the validation sample are discussed.
The Effects of Dependent Interviewing on Responses to Questions on Income Sources
Using an experimental design, we compare two alternative approaches to dependent interviewing (proactive and reactive) with traditional independent interviewing on a module of questions about sources of income. We believe this to be the first large-scale quantitative comparison of proactive and reactive dependent interviewing. The three approaches to questioning are compared in terms of their impact on under-reporting of income sources and related bivariate statistics. The study design also enables identification of the characteristics of respondents whose responses are sensitive to the mode of interviewing. We conclude that under-reporting can be significantly greater with independent interviewing than with either form of dependent interviewing, especially for income sources that are relatively common or relatively easy to forget. We find that dependent interviewing is particularly helpful as a recall aid for respondents below retirement age and registered disabled persons.
Mapping and identification of essential gene functions on the X chromosome of Drosophila
The Drosophila melanogaster genome consists of four chromosomes that contain 165 Mb of DNA, 120 Mb of which are euchromatic. The two Drosophila Genome Projects, in collaboration with Celera Genomics Systems, have sequenced the genome, complementing the previously established physical and genetic maps. In addition, the Berkeley Drosophila Genome Project has undertaken large‐scale functional analysis based on mutagenesis by transposable P element insertions into autosomes. Here, we present a large‐scale P element insertion screen for vital gene functions and a BAC tiling map for the X chromosome. A collection of 501 X‐chromosomal P element insertion lines was used to map essential genes cytogenetically and to establish short sequence tags (STSs) linking the insertion sites to the genome. The distribution of the P element integration sites, the identified genes and transcription units as well as the expression patterns of the P‐element‐tagged enhancers is described and discussed
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Using QR codes to aid accessibility in a museum
Purpose – This paper describes visitors' reactions to using an Apple iPad or smartphone to follow trails in a museum by scanning QR codes and draws conclusions on the potential for this technology to help improve accessibility at low-cost.
Design/methodology/approach – Activities were devised which involved visitors following trails around museum objects, each labelled with a QR code and symbolised text. Visitors scanned the QR codes using a mobile device which then showed more information about an object. Project-team members acted as participant-observers, engaging with visitors and noting how they used the system. Experiences from each activity fed into the design of the next.
Findings – Some physical and technical problems with using QR codes can be overcome with the introduction of simple aids, particularly using movable object labels. A layered approach to information access is possible with the first layer comprising a label, the second a mobile-web enabled screen and the third choices of text, pictures, video and audio. Video was especially appealing to young people. The ability to repeatedly watch video or listen to audio seemed to be appreciated by visitors with learning disabilities. This approach can have low equipment-cost. However, maintaining the information behind labels and keeping-up with technological changes are on-going processes.
Originality/value – Using QR codes on movable, symbolised object labels as part of a layered information system might help modestly-funded museums enhance their accessibility, particularly as visitors increasingly arrive with their own smartphones or tablets
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