419 research outputs found
The Value of p-Value in Biomedical Research
Significance tests and the corresponding p-values play a crucial role in decision making. In this commentary the meaning, interpretation and misinterpretation of p-values is presented. Alternatives for evaluating the reported evidence are also discussed
Super-resolving phase measurements with a multi-photon entangled state
Using a linear optical elements and post-selection, we construct an entangled
polarization state of three photons in the same spatial mode. This state is
analogous to a ``photon-number path entangled state'' and can be used for
super-resolving interferometry. Measuring a birefringent phase shift, we
demonstrate two- and three-fold improvements in phase resolution.Comment: 4 pages, 3 figure
Evaluation of morbidity, mortality and outcome following cervical spine injuries in elderly patients (S. A. Malik et al.)
Contains fulltext :
71260.pdf (publisher's version ) (Closed access
Designing nutrition-based interventional trials for the future: addressing the known knowns
Abstract The consistent decline in critical illness mortality has a significant effect on trial design, whereby either an improbable effect sizes or large number of patients are required. The signal-to-noise ratio is of particular interest for the critically ill. When considering the potential signal, interventions need to match outcomes in regard to biological plausibility. Provision of nutrition is a complex decision with many underappreciated aspects of noise. However, a fundamental interaction is often not accounted for time. Working as a community to evolve trial design will be our challenge for nutrition interventions in the critically ill for the future
User needs elicitation via analytic hierarchy process (AHP). A case study on a Computed Tomography (CT) scanner
Background:
The rigorous elicitation of user needs is a crucial step for both medical device design and purchasing. However, user needs elicitation is often based on qualitative methods whose findings can be difficult to integrate into medical decision-making. This paper describes the application of AHP to elicit user needs for a new CT scanner for use in a public hospital.
Methods:
AHP was used to design a hierarchy of 12 needs for a new CT scanner, grouped into 4 homogenous categories, and to prepare a paper questionnaire to investigate the relative priorities of these. The questionnaire was completed by 5 senior clinicians working in a variety of clinical specialisations and departments in the same Italian public hospital.
Results:
Although safety and performance were considered the most important issues, user needs changed according to clinical scenario. For elective surgery, the five most important needs were: spatial resolution, processing software, radiation dose, patient monitoring, and contrast medium. For emergency, the top five most important needs were: patient monitoring, radiation dose, contrast medium control, speed run, spatial resolution.
Conclusions:
AHP effectively supported user need elicitation, helping to develop an analytic and intelligible framework of decision-making. User needs varied according to working scenario (elective versus emergency medicine) more than clinical specialization. This method should be considered by practitioners involved in decisions about new medical technology, whether that be during device design or before deciding whether to allocate budgets for new medical devices according to clinical functions or according to hospital department
MaxAlign: maximizing usable data in an alignment
<p>Abstract</p> <p>Background</p> <p>The presence of gaps in an alignment of nucleotide or protein sequences is often an inconvenience for bioinformatical studies. In phylogenetic and other analyses, for instance, gapped columns are often discarded entirely from the alignment.</p> <p>Results</p> <p>MaxAlign is a program that optimizes the alignment prior to such analyses. Specifically, it maximizes the number of nucleotide (or amino acid) symbols that are present in gap-free columns – the alignment area – by selecting the optimal subset of sequences to exclude from the alignment.</p> <p>MaxAlign can be used prior to phylogenetic and bioinformatical analyses as well as in other situations where this form of alignment improvement is useful. In this work we test MaxAlign's performance in these tasks and compare the accuracy of phylogenetic estimates including and excluding gapped columns from the analysis, with and without processing with MaxAlign. In this paper we also introduce a new simple measure of tree similarity, Normalized Symmetric Similarity (NSS) that we consider useful for comparing tree topologies.</p> <p>Conclusion</p> <p>We demonstrate how MaxAlign is helpful in detecting misaligned or defective sequences without requiring manual inspection. We also show that it is not advisable to exclude gapped columns from phylogenetic analyses unless MaxAlign is used first. Finally, we find that the sequences removed by MaxAlign from an alignment tend to be those that would otherwise be associated with low phylogenetic accuracy, and that the presence of gaps in any given sequence does not seem to disturb the phylogenetic estimates of <it>other </it>sequences.</p> <p>The MaxAlign web-server is freely available online at http://www.cbs.dtu.dk/services/MaxAlign where supplementary information can also be found. The program is also freely available as a Perl stand-alone package.</p
The response of mental health professionals to clients seeking help to change or redirect same-sex sexual orientation
<p>Abstract</p> <p>Background</p> <p>we know very little about mental health practitioners' views on treatments to change sexual orientation. Our aim was to survey a representative sample of professional members of the main United Kingdom psychotherapy and psychiatric organisations about their views and practices concerning such treatments.</p> <p>Methods</p> <p>We sent postal questions to mental health professionals who were members of British Psychological Society, the British Association for Counselling and Psychotherapy, the United Kingdom Council for Psychotherapy and the Royal College of Psychiatrists. Participants were asked to give their views about treatments to change homosexual desires and describe up to five patients each, whom they has treated in this way.</p> <p>Results</p> <p>Of 1848 practitioners contacted, 1406 questionnaires were returned and 1328 could be analysed. Although only 55 (4%) of therapists reported that they would attempt to change a client's sexual orientation if one consulted asking for such therapy, 222 (17%) reported having assisted at least one client/patient to reduce or change his or her homosexual or lesbian feelings. 413 patients were described by these 222 therapists: 213 (52%) were seen in private practice and 117 (28%) were not followed up beyond the period of treatment. Counselling was the commonest (66%) treatment offered and there was no sign of a decline in treatments in recent years. 159 (72%) of the 222 therapists who had provided such treatment considered that a service should be available for people who want to change their sexual orientation. Client/patient distress and client/patient autonomy were seen as reasons for intervention; therapists paid attention to religious, cultural and moral values causing internal conflict.</p> <p>Conclusion</p> <p>A significant minority of mental health professionals are attempting to help lesbian, gay and bisexual clients to become heterosexual. Given lack of evidence for the efficacy of such treatments, this is likely to be unwise or even harmful.</p
The contribution of microlensing surveys to the distance scale
In the early nineties several teams started large scale systematic surveys of
the Magellanic Clouds and the Galactic Bulge to search for microlensing
effects. As a by product, these groups have created enormous time-series
databases of photometric measurements of stars with a temporal sampling
duration and accuracy which are unprecedented. They provide the opportunity to
test the accuracy of primary distance indicators, such as Cepheids, RRLyrae
stars, the detached eclipsing binaries, or the luminosity of the red clump. We
will review the contribution of the microlensing surveys to the understanding
of the physics of the primary distance indicators, recent differential studies
and direct distance determinations to the Magellanic Clouds and the Galactic
Bulge.Comment: Invited review article to appear in: `Post-Hipparcos Cosmic Candles',
A. Heck & F. Caputo (Eds), Kluwer Academic Publ., Dordrecht, in press. 21
pages; uses Kluwer's crckapb.sty LaTeX style file, enclose
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