388 research outputs found
Interdisciplinary research collegium in advanced maritime systems design
The education of naval architects, marine engineers and others who are the active contributors to the ship design processes is heavily focussed on engineering fundamentals, often aligned with traditional university course constraints. The concept of a research collegium is described whose aim is to provide an environment where young people in their formative postgraduate years can learn and work in a small, mixed discipline group drawn from the worldwide maritime community to develop their skills whilst completing a project in advanced ship design. The brief that initiates each project sets challenging user requirements which encourage each team to develop an imaginative solution, using their individual knowledge and experience, together with learning derived from teaching which form a common element of the early part of the collegiu
Rapid convergence of time-averaged frequency in phase synchronized systems
Numerical and experimental evidence is presented to show that many phase
synchronized systems of non-identical chaotic oscillators, where the chaotic
state is reached through a period-doubling cascade, show rapid convergence of
the time-averaged frequency. The speed of convergence toward the natural
frequency scales as the inverse of the measurement period. The results also
suggest an explanation for why such chaotic oscillators can be phase
synchronized.Comment: 6 pages, 9 figure
High-Energy Aspects of Solar Flares: Overview of the Volume
In this introductory chapter, we provide a brief summary of the successes and
remaining challenges in understanding the solar flare phenomenon and its
attendant implications for particle acceleration mechanisms in astrophysical
plasmas. We also provide a brief overview of the contents of the other chapters
in this volume, with particular reference to the well-observed flare of 2002
July 23Comment: This is the introductory article for a monograph on the physics of
solar flares, inspired by RHESSI observations. The individual articles are to
appear in Space Science Reviews (2011
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A randomised controlled trial of treatments of childhood anxiety disorder in the context of maternal anxiety disorder: clinical and cost-effectiveness outcomes
Background: This study evaluated whether clinical and economic outcomes from CBT for child anxiety disorders in the context of maternal anxiety disorders are improved by adding treatment focused on (i) maternal anxiety disorders, or (ii) mother-child interactions. Methods: 211 children (7 – 12 years, 85% White British, 52% female) with a primary anxiety disorder, whose mothers also had a current anxiety disorder, were randomised to receive (i) child-focused CBT with non-specific control interventions (CCBT+Con), (ii) CCBT with CBT for the maternal anxiety disorder (CCBT+MCBT), or (iii) CCBT with an intervention targeting the mother-child interaction (CCBT+MCI). A cost-utility analysis from a societal perspective was conducted using mother/child combined Quality Adjusted Life Years (QALYs). [Trial registration: https://doi.org/10.1186/ISRCTN19762288]. Results: MCBT was associated with immediate reductions in maternal anxiety compared to the non-specific control; however, after children had also received CCBT, maternal outcomes in the CCBT+MCI and CCBT+Con arms improved and CCBT+MCBT was no longer superior. Neither CCBT+MCBT nor CCBT+MCI conferred a benefit over CCBT+Con in terms of child anxiety disorder diagnoses post-treatment [primary outcome] (adj RR: 1.22 (95% CI 0.88, 1.67), p = .23; adj RR: 1.21 (95% CI 0.88, 1.65), p = .24 respectively) or global improvement ratings (adj RR 1.25 (95% CI 0.99, 1.57), p = .06; adj RR 1.18 (95% CI 0.93, 1.50), p = .17) or six and 12 months later. No significant differences between the groups were found on the main economic outcome measures (child/mother combined QALY mean difference: CCBT+MCBT vs CCBT+Con: -0.04 (95% CI -0.12, 0.04), p = 0.29; CCBT+MCI vs CCBT+Con: 0.02 (95% CI -0.05, -0.09), p = 0.54). CCBT+MCI was associated with non-significantly higher costs than CCBT (mean difference: £154 (95% CI -£1239, £1547), p = 0.83) but, when taking into account sampling uncertainty, it may be cost-effective compared with CCBT alone. Conclusions: Good outcomes were achieved for children and their mothers across treatment arms. There was no evidence of significant clinical benefit from supplementing CCBT with either CBT for the maternal anxiety disorder or treatment focussed on mother-child interactions, but the addition of MCI (and not MCBT) may be cost-effective. Keywords: Child; anxiety; mother; parent-child interaction; CBT
Optimal Hypercontractivity for Fermi Fields and Related Non-Commutative Integration
Optimal hypercontractivity bounds for the fermion oscillator semigroup are
obtained. These are the fermion analogs of the optimal hypercontractivity
bounds for the boson oscillator semigroup obtained by Nelson. In the process,
several results of independent interest in the theory of non-commutative
integration are established. {}.Comment: 18 p., princeton/ecel/7-12-9
The Evolution of Sunspot Magnetic Fields Associated with a Solar Flare
Solar flares occur due to the sudden release of energy stored in
active-region magnetic fields. To date, the pre-cursors to flaring are still
not fully understood, although there is evidence that flaring is related to
changes in the topology or complexity of an active region's magnetic field.
Here, the evolution of the magnetic field in active region NOAA 10953 was
examined using Hinode/SOT-SP data, over a period of 12 hours leading up to and
after a GOES B1.0 flare. A number of magnetic-field properties and low-order
aspects of magnetic-field topology were extracted from two flux regions that
exhibited increased Ca II H emission during the flare. Pre-flare increases in
vertical field strength, vertical current density, and inclination angle of ~
8degrees towards the vertical were observed in flux elements surrounding the
primary sunspot. The vertical field strength and current density subsequently
decreased in the post-flare state, with the inclination becoming more
horizontal by ~7degrees. This behaviour of the field vector may provide a
physical basis for future flare forecasting efforts.Comment: Accepted for Publication in Solar Physics. 16 pages, 4 figure
Shot noise in normal metal-d-wave superconducting junctions
We present theoretical calculations and predictions for the shot noise in
voltage biased junctions of superconductors and normal metal
counter-electrodes. In the clean limit for the d-wave superconductor the shot
noise vanishes at zero voltage because of resonant Andreev reflection by
zero-energy surface bound states. We examine the sensitivity of this resonance
to impurity scattering. We report theoretical results for the magnetic field
dependence of the shot noise, as well the fingerprints of subdominant - and
pairing channels.Comment: 15 pages, 8 figures and 3 tables embedde
Critical properties of the Fermi-Bose Kondo and pseudogap Kondo models: Renormalized perturbation theory
Magnetic impurities coupled to both fermionic and bosonic baths or to a
fermionic bath with pseudogap density of states, described by the Fermi-Bose
Kondo and pseudogap Kondo models, display non-trivial intermediate coupling
fixed points associated with critical local-moment fluctuations and local
non-Fermi liquid behavior. Based on renormalization group together with a
renormalized perturbation expansion around the free-impurity limit, we
calculate various impurity properties in the vicinity of those
intermediate-coupling fixed points. In particular, we compute the conduction
electron T matrix, the impurity susceptibility, and the residual impurity
entropy, and relate our findings to certain scenarios of local quantum
criticality in strongly correlated lattice models.Comment: 16 pages, 5 figs; (v2) large-N results for entropy of Bose-Kondo
model added; (v3) final version as publishe
Navigating 'the pit of doom': Affective responses to teaching 'grammar'
publication-status: Publishedtypes: ArticleThis article presents the outcomes of a study investigating current secondary English teachers' beliefs about grammar teaching, and illustrates the salience of teachers' emotional response to the issue. Interviews with 31 teachers reveal two discourses which frame the ways in which teachers express their feelings: a dominant discourse of grammar as threatening, reactionary and dull, and an oppositional discourse which positions grammar as inspiring, fascinating, and empowering. The influence of these discourses on practice is explored, along with examples of how attitudes can change as a result of participation in a research project. © 2012 National Association for the Teaching of English
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