12,597 research outputs found
High transients suppressed in electromagnetic devices
A bifilar winding around the magnetic core of electromagnetic devices suppresses high transient voltages. The winding is alternately spaced vertically and radially from the core to achieve a high coefficient of coupling
'TIDieR-ing up' the reporting of interventions in stroke research:The importance of knowing what is in the 'black box'
Evidence-based interventions cannot be provided unless there is a clear understanding of what the intervention is. Many published randomized trials, systematic reviews, and guidelines contain incomplete intervention descriptions. For non-pharmacological interventions, such as stroke rehabilitation, the reporting is particularly poor. Contributors to this problem include lack of attention to this issue and awareness of what constitutes a complete intervention description by authors, reviewers, journals, and editors. Part of the solution is for authors to follow guidance about how to describe interventions, such as the Template for Intervention Description and Replication statement. Improving stroke interventions reporting will remove one of the current barriers to evidence-based care. </jats:p
Decision aids for randomised controlled trials : a qualitative exploration of stakeholders' views
Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions. Funding: This work was supported by personal fellowship award (to KG) from the Chief Scientist Office of the Scottish Governments Health and Social Care Directorates, grant number [PDF/09/01]. The Health Services Research Unit is supported by a core grant from the Chief Scientist Office of the Scottish Government Health and Social Care Directorates.Peer reviewedPublisher PD
Physics of SNeIa and Cosmology
We give an overview of the current understanding of Type Ia supernovae
relevant for their use as cosmological distance indicators. We present the
physical basis to understand their homogeneity of the observed light curves and
spectra and the observed correlations. This provides a robust method to
determine the Hubble constant, 67 +- 8 (2 sigma) km/Mpc/sec, independently from
primary distance indicators.
We discuss the uncertainties and tests which include SNe Ia based distance
determinations prior to delta-Ceph. measurements for the host galaxies. Based
on detailed models, we study the small variations from homogeneities and their
observable consequences. In combination with future data, this underlines the
suitability and promises the refinements needed to determine accurate relative
distances within 2 to 3 % and to use SNe Ia for high precision cosmology.Comment: to be published in "Stellar Candles", eds. Gieren et al. Lecture
Notes in Physics (http://link.springer.de/series/lnpp
Evidence Against an Association Between Gamma-Ray Bursts and Type I Supernovae
We present a rigorous method, based on Bayesian inference, for calculating
the odds favoring the hypothesis that any particular class of astronomical
transients produce gamma-ray bursts over the hypothesis that they do not. We
then apply this method to a sample of 83 Type Ia supernovae and a sample of 20
Type Ib-Ic supernovae. We find overwhelming odds against the hypothesis that
all Type Ia supernovae produce gamma-ray bursts, whether at low redshift
() or high-redshift (), and very large odds ()
against the hypothesis that all Type Ib, Ib/c, and Ic supernovae produce
observable gamma-ray bursts. We find large odds () against the hypothesis
that a fraction of Type Ia supernovae produce observable gamma-ray bursts, and
moderate odds () against the hypothesis that a fraction of Type Ib-Ic
supernovae produce observable bursts. We have also re-analyzed both a corrected
version of the Wang & Wheeler sample of Type Ib-Ic SNe and our larger sample of
20 Type Ib-Ic SNe, using a generalization of their frequentist method. We find
no significant evidence in either case of a correlation between Type Ib-Ic SNe
and GRBs, consistent with the very strong evidence against such a correlation
that we find from our Bayesian analysis.Comment: 45 pages, 2 PostScript figures. Uses AASTEX macros. Submitted to The
Astrophysical Journa
Investigating the relationship between predictability and imbalance in minimisation : a simulation study
Peer reviewedPublisher PD
Strengthening the ethical assessment of placebo-controlled surgical trials : three proposals
Peer reviewedPublisher PD
Attractors of directed graph IFSs that are not standard IFS attractors and their Hausdorff measure
For directed graph iterated function systems (IFSs) defined on R, we prove
that a class of 2-vertex directed graph IFSs have attractors that cannot be the
attractors of standard (1-vertex directed graph) IFSs, with or without
separation conditions. We also calculate their exact Hausdorff measure. Thus we
are able to identify a new class of attractors for which the exact Hausdorff
measure is known
- ā¦