RAMESES publication standards: meta-narrative reviews

PMCID: PMC3558334This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

Dimensional analysis using toric ideals: Primitive invariants

© 2014 Atherton et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Classical dimensional analysis in its original form starts by expressing the units for derived quantities, such as force, in terms of power products of basic units M, L, T etc. This suggests the use of toric ideal theory from algebraic geometry. Within this the Graver basis provides a unique primitive basis in a well-defined sense, which typically has more terms than the standard Buckingham approach. Some textbook examples are revisited and the full set of primitive invariants found. First, a worked example based on convection is introduced to recall the Buckingham method, but using computer algebra to obtain an integer K matrix from the initial integer A matrix holding the exponents for the derived quantities. The K matrix defines the dimensionless variables. But, rather than this integer linear algebra approach it is shown how, by staying with the power product representation, the full set of invariants (dimensionless groups) is obtained directly from the toric ideal defined by A. One candidate for the set of invariants is a simple basis of the toric ideal. This, although larger than the rank of K, is typically not unique. However, the alternative Graver basis is unique and defines a maximal set of invariants, which are primitive in a simple sense. In addition to the running example four examples are taken from: a windmill, convection, electrodynamics and the hydrogen atom. The method reveals some named invariants. A selection of computer algebra packages is used to show the considerable ease with which both a simple basis and a Graver basis can be found.The third author received funding from Leverhulme Trust Emeritus Fellowship (1-SST-U445) and United Kingdom EPSRC grant: MUCM EP/D049993/1

Cues and knowledge structures used by mental-health professionals when making risk assessments

Background: Research into mental-health risks has tended to focus on epidemiological approaches and to consider pieces of evidence in isolation. Less is known about the particular factors and their patterns of occurrence that influence clinicians’ risk judgements in practice. Aims: To identify the cues used by clinicians to make risk judgements and to explore how these combine within clinicians’ psychological representations of suicide, self-harm, self-neglect, and harm to others. Method: Content analysis was applied to semi-structured interviews conducted with 46 practitioners from various mental-health disciplines, using mind maps to represent the hierarchical relationships of data and concepts. Results: Strong consensus between experts meant their knowledge could be integrated into a single hierarchical structure for each risk. This revealed contrasting emphases between data and concepts underpinning risks, including: reflection and forethought for suicide; motivation for self-harm; situation and context for harm to others; and current presentation for self-neglect. Conclusions: Analysis of experts’ risk-assessment knowledge identified influential cues and their relationships to risks. It can inform development of valid risk-screening decision support systems that combine actuarial evidence with clinical expertise

Quantum Vacuum Contribution to the Momentum of the Dielectric Media

Momentum transfer between matter and electromagnetic field is analyzed. The related equations of motion and conservation laws are derived using relativistic formalism. Their correspondence to various, at first sight self-contradicting, experimental data (the so called Abraham-Minkowski controversy) is demonstrated. A new, Casimir like, quantum phenomenon is predicted: contribution of vacuum fluctuations to the motion of dielectric liquids in crossed electric and magnetic fields. Velocities about $50nm/s$ can be expected due to the contribution of high frequency vacuum modes

Indications of Universal Excess Fluctuations in Nonequilibrium Systems

The fluctuation in electric current in nonequilibrium steady states is investigated by molecular dynamics simulation of macroscopically uniform conductors. At low frequencies, appropriate decomposition of the spectral intensity of current into thermal and excess fluctuations provides a simple picture of excess fluctuations behaving as shot noise. This indicates that the fluctuation-dissipation relation may be violated in a universal manner by the appearance of shot noise for a wide range of systems with particle or momentum transport.Comment: 4 pages, 4 figures; title changed, major revision; to appear in J. Phys. Soc. Jp

Using XML and XSLT for flexible elicitation of mental-health risk knowledge

Current tools for assessing risks associated with mental-health problems require assessors to make high-level judgements based on clinical experience. This paper describes how new technologies can enhance qualitative research methods to identify lower-level cues underlying these judgements, which can be collected by people without a specialist mental-health background. Methods and evolving results: Content analysis of interviews with 46 multidisciplinary mental-health experts exposed the cues and their interrelationships, which were represented by a mind map using software that stores maps as XML. All 46 mind maps were integrated into a single XML knowledge structure and analysed by a Lisp program to generate quantitative information about the numbers of experts associated with each part of it. The knowledge was refined by the experts, using software developed in Flash to record their collective views within the XML itself. These views specified how the XML should be transformed by XSLT, a technology for rendering XML, which resulted in a validated hierarchical knowledge structure associating patient cues with risks. Conclusions: Changing knowledge elicitation requirements were accommodated by flexible transformations of XML data using XSLT, which also facilitated generation of multiple data-gathering tools suiting different assessment circumstances and levels of mental-health knowledge

Pleasure and pedagogy: the consumption of DVD add-ons among Irish teenagers

This article addresses the issue of young people and media use in the digital age, more specifically the interconnection between new media pleasures and pedagogy as they relate to the consumption of DVD add-ons. Arguing against the view of new media as having predominantly detrimental effects on young people, the authors claim that new media can enable young people to develop media literacy skills and are of the view that media literacy strategies must be based on an understanding and legitimating of young people's use patterns and pleasures. The discussion is based on a pilot research project on the use patterns and pleasures of use with a sample of Irish teenagers. They found that DVDs were used predominantly in the home context, and that, while there was variability in use between the groups, overall they developed critical literacy skills and competences which were interwoven into their social life and projects of identity construction. The authors suggest that these findings could be used to develop DVDs and their add-on features as a learning resource in the more formal educational setting and they go on to outline the potential teaching benefits of their use across a range of pedagogical areas

Duration of Nocturnal Hypoglycemia Before Seizures

OBJECTIVE—Despite a high incidence of nocturnal hypoglycemia documented by the use of continuous glucose monitoring (CGM), there are no reports in the literature of nocturnal hypoglycemic seizures while a patient is wearing a CGM device

OpenLearn Research Report 2006-2008

This report takes the experience of OpenLearn over its two-years of operation to reflect on what it means to offer free resources and the issues that we have been able to explore and learn from. The structure of the document is: (1) The OpenLearn initiative - an overview (2) OpenLearn research methods (3) Designing for Open Content (4) Types of user of OpenLearn (5) OpenLearn modes of us