11,412 research outputs found
Electrical switching and interferometry of massive Dirac particles in topological insulators constrictions
We investigate the electrical switching of charge and spin transport in a
topological insulator nanoconstriction in a four terminal device. The switch of
the edge channels is caused by the coupling between edge states which overlap
in the constriction and by the tunneling effects at the contacts and therefore
can be manipulated by tuning the applied voltages on the split-gate or by
geometrical etching. The switching mechanism can be conveniently studied by
electron interferometry involving the measurements of the current in different
configurations of the side gates, while the applied bias from the external
leads can be tuned to obtain pure charge or pure spin currents (charge- and
spin- bias configurations). Relevant signatures of quantum confinement effects,
quantum size effects and energy gap are evident in the Fabry-Perot physics of
the device allowing for a full characterization of the charge and spin
currents. The proposed electrical switching behavior offers an efficient tool
to manipulate topological edge state transport in a controllable way.Comment: 10 pages; 14 figure
SmokeFree Sports Project Report
Children and young people are amongst the most vulnerable groups in society and are highly susceptible to smoking experimentation and addiction. In Liverpool, smoking prevalence is significantly higher than the UK average. Therefore early intervention strategies are required for smoking prevention and cessation. Research has found a negative association between smoking and physical activity. SmokeFree Sports aims to explore whether physical activity and sport can be used to promote the smoke free message to children and young people.
SmokeFree Sports is an innovative multi-dimensional campaign that incorporates social-marketing strategies alongside the provision of sports and physical activities to: a) de-normalise smoking among youth b) empower youth to stay smoke free, and c) increase awareness of the dangers of smoking using positive messaging through the medium of sport and physical activity. This project is delivered across Liverpool and aims to reduce the prevalence of smoking and prevent the uptake of smoking in children and young people.
The initiative, which is managed by Liverpool John Moores University in partnership with Liverpool PCT, employs a variety of strategies to promote and deliver the smoke free message to children and young people including a) training sports coaches and teachers to deliver the smoke free message, b) delivering SFS messages in schools and youth clubs through sport and physical activity, c) asking children to sign a pledge to be smoke free, d) support voluntary sports clubs to adopt a smoke free policy on their playing fields, e) encouraging organizations and individuals interested in health and sport to sign up to the SmokeFree Sports Charter and f) signposting children to smoking cessation services
Neural networks in geophysical applications
Neural networks are increasingly popular in geophysics.
Because they are universal approximators, these
tools can approximate any continuous function with an
arbitrary precision. Hence, they may yield important
contributions to finding solutions to a variety of geophysical applications.
However, knowledge of many methods and techniques
recently developed to increase the performance
and to facilitate the use of neural networks does not seem
to be widespread in the geophysical community. Therefore,
the power of these tools has not yet been explored to
their full extent. In this paper, techniques are described
for faster training, better overall performance, i.e., generalization,and the automatic estimation of network size
and architecture
Synthesis and biological evaluation of phosphonated dihydroisoxazole nucleosides
Phosphonated isoxazolinyl nucleosides have been prepared via 1,3-dipolar cycloaddition reaction of nitrile oxides with
corresponding vinyl or allyl nucleobases for antiviral studies. The cytotoxicity, the anti-HSV activity and the RT-inhibitory activity
of the obtained compounds were evaluated and compared with those of AZT and diethyl{(10SR,40RS)-10-[[(5-methyl-2,4-dioxo-3,4-
dihydropyrimidin-1(2H)-yl)]-30-methyl-20-oxa-30-azacyclopent-40-yl]}methylphosphonate, a saturated phosphonated dihydroisoxazole
nucleoside analogue
Stellar population gradients from cosmological simulations: dependence on mass and environment in local galaxies
The age and metallicity gradients for a sample of group and cluster galaxies
from N-body+hydrodynamical simulation are analyzed in terms of galaxy stellar
mass. Dwarf galaxies show null age gradient with a tail of high and positive
values for systems in groups and cluster outskirts. Massive systems have
generally zero age gradients which turn to positive for the most massive ones.
Metallicity gradients are distributed around zero in dwarf galaxies and become
more negative with mass; massive galaxies have steeper negative metallicity
gradients, but the trend flatten with mass. In particular, fossil groups are
characterized by a tighter distribution of both age and metallicity gradients.
We find a good agreement with both local observations and independent
simulations. The results are also discussed in terms of the central age and
metallicity, as well as the total colour, specific star formation and velocity
dispersion.Comment: 9 pages, 5 figures, accepted for publication on MNRA
Teaching Teachers for the Future (TTF) Project: Development of the TTF TPACK survey instrument
This paper presents a summary of the key findings of the TTF TPACK Survey developed and administered for the Teaching the Teachers for the Future (TTF) Project implemented in 2011. The TTF Project, funded by an Australian Government ICT Innovation Fund grant, involved all 39 Australian Higher Education Institutions which provide initial teacher education. TTF data collections were undertaken at the end of Semester 1 (T1) and at the end of Semester 2 (T2) in 2011. A total of 12881 participants completed the first survey (T1) and 5809 participants completed the second survey (T2). Groups of like-named items from the T1 survey were subject to a battery of complementary data analysis techniques. The psychometric properties of the four scales: Confidence - teacher items; Usefulness - teacher items; Confidence - student items; Usefulness- student items, were confirmed both at T1 and T2. Among the key findings summarised, at the national level, the scale: Confidence to use ICT as a teacher showed measurable growth across the whole scale from T1 to T2, and the scale: Confidence to facilitate student use of ICT also showed measurable growth across the whole scale from T1 to T2. Additional key TTF TPACK Survey findings are summarised
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