46,234 research outputs found
Generative Roles: Assessing Sustained Involvement in Generativity
Abstract Generative roles refer to observable, behavioral community positions that embody aspects of teaching and nurturing that are central to the concept of generativity. Two studies are presented that describe generative roles in a community sample and provide psychometric data for a short index of generative roles. The first study also provides reliability and validity data from a second informant. The second study examines generative roles at different stages of adolescence and adulthood. Participants were asked 8 yes/no questions about a variety of community roles. The validity of the GRI was supported by significant correlations with the Loyola Generativity Scale, a widely used measure of generative concern (r=.33), and measures of related constructs. The correlations were similar across age categories. The Generative Roles Index has good psychometric qualities and complements existing measures of generativity by providing behavioral, observable data on roles
Paraoxonase gene polymorphisms and haplotype analysis in a stroke population
Peer reviewedPublisher PD
Black hole evaporation in a spherically symmetric non-commutative space-time
Recent work in the literature has studied the quantum-mechanical decay of a
Schwarzschild-like black hole, formed by gravitational collapse, into
almost-flat space-time and weak radiation at a very late time. The relevant
quantum amplitudes have been evaluated for bosonic and fermionic fields,
showing that no information is lost in collapse to a black hole. On the other
hand, recent developments in noncommutative geometry have shown that, in
general relativity, the effects of non-commutativity can be taken into account
by keeping the standard form of the Einstein tensor on the left-hand side of
the field equations and introducing a modified energy-momentum tensor as a
source on the right-hand side. Relying on the recently obtained
non-commutativity effect on a static, spherically symmetric metric, we have
considered from a new perspective the quantum amplitudes in black hole
evaporation. The general relativity analysis of spin-2 amplitudes has been
shown to be modified by a multiplicative factor F depending on a constant
non-commutativity parameter and on the upper limit R of the radial coordinate.
Limiting forms of F have been derived which are compatible with the adiabatic
approximation.Comment: 8 pages, Latex file with IOP macros, prepared for the QFEXT07
Conference, Leipzig, September 200
Spin-2 Amplitudes in Black-Hole Evaporation
Quantum amplitudes for gravitational-wave perturbations of
Einstein/scalar collapse to a black hole are treated by analogy with
Maxwell perturbations. The spin-2 perturbations split into parts with odd and
even parity. We use the Regge-Wheeler gauge; at a certain point we make a gauge
transformation to an asymptotically-flat gauge, such that the metric
perturbations have the expected falloff behaviour at large radii. By analogy
with , for natural 'coordinate' variables are given by the magnetic
part of the Weyl tensor, which can be taken as boundary
data on a final space-like hypersurface . For simplicity, we take the
data on the initial surface to be exactly spherically-symmetric. The
(large) Lorentzian proper-time interval between and ,
measured at spatial infinity, is denoted by . We follow Feynman's
prescription and rotate into the complex: , for . The corresponding complexified {\it
classical} boundary-value problem is expected to be well-posed. The Lorentzian
quantum amplitude is recovered by taking the limit as . For
boundary data well below the Planck scale, and for a locally supersymmetric
theory, this involves only the semi-classical amplitude , where denotes the second-variation classical
action. The relations between the and natural boundary data,
involving supersymmetry, are investigated using 2-component spinor language in
terms of the Maxwell field strength and the Weyl spinor
Soliton blue-shift in tapered photonic crystal fiber
We show that solitons undergo a strong blue shift in fibers with a dispersion
landscape that varies along the direction of propagation. The experiments are
based on a small-core photonic crystal fiber, tapered to have a core diameter
that varies continuously along its length, resulting in a zero-dispersion
wavelength that moves from 731 nm to 640 nm over the transition. The central
wavelength of a soliton translates over 400 nm towards shorter wavelength. This
accompanied by strong emission of radiation into the UV and IR spectral region.
The experimental results are confirmed by numerical simulation.Comment: 10 pages, 4 figure
User interface design for mobile-based sexual health interventions for young people: Design recommendations from a qualitative study on an online Chlamydia clinical care pathway
Background: The increasing pervasiveness of mobile technologies has given potential to transform healthcare by facilitating clinical management using software applications. These technologies may provide valuable tools in sexual health care and potentially overcome existing practical and cultural barriers to routine testing for sexually transmitted infections. In order to inform the design of a mobile health application for STIs that supports self-testing and self-management by linking diagnosis with online care pathways, we aimed to identify the dimensions and range of preferences for user interface design features among young people. Methods: Nine focus group discussions were conducted (n=49) with two age-stratified samples (16 to 18 and 19 to 24 year olds) of young people from Further Education colleges and Higher Education establishments. Discussions explored young people's views with regard to: the software interface; the presentation of information; and the ordering of interaction steps. Discussions were audio recorded and transcribed verbatim. Interview transcripts were analysed using thematic analysis. Results: Four over-arching themes emerged: privacy and security; credibility; user journey support; and the task-technology-context fit. From these themes, 20 user interface design recommendations for mobile health applications are proposed. For participants, although privacy was a major concern, security was not perceived as a major potential barrier as participants were generally unaware of potential security threats and inherently trusted new technology. Customisation also emerged as a key design preference to increase attractiveness and acceptability. Conclusions: Considerable effort should be focused on designing healthcare applications from the patient's perspective to maximise acceptability. The design recommendations proposed in this paper provide a valuable point of reference for the health design community to inform development of mobile-based health interventions for the diagnosis and treatment of a number of other conditions for this target group, while stimulating conversation across multidisciplinary communities
Transition radiation by matter-wave solitons in optical lattices
We demonstrate that matter-wave solitary pulses formed from Bose condensed
atoms moving inside optical lattices continuously radiate dispersive matter
waves with prescribed momentum. Our analytical results for the radiation
parameters and the soliton decay rate are found to be in excellent agreement
with numerical modelling performed for experimentally relevant parameters.Comment: accepted to PR
Gravitational amplitudes in black-hole evaporation: the effect of non-commutative geometry
Recent work in the literature has studied the quantum-mechanical decay of a
Schwarzschild-like black hole, formed by gravitational collapse, into
almost-flat space-time and weak radiation at a very late time. The relevant
quantum amplitudes have been evaluated for bosonic and fermionic fields,
showing that no information is lost in collapse to a black hole. On the other
hand, recent developments in noncommutative geometry have shown that, in
general relativity, the effects of noncommutativity can be taken into account
by keeping the standard form of the Einstein tensor on the left-hand side of
the field equations and introducing a modified energy-momentum tensor as a
source on the right-hand side. The present paper, relying on the recently
obtained noncommutativity effect on a static, spherically symmetric metric,
considers from a new perspective the quantum amplitudes in black hole
evaporation. The general relativity analysis of spin-2 amplitudes is shown to
be modified by a multiplicative factor F depending on a constant
non-commutativity parameter and on the upper limit R of the radial coordinate.
Limiting forms of F are derived which are compatible with the adiabatic
approximation here exploited. Approximate formulae for the particle emission
rate are also obtained within this framework.Comment: 14 pages, 2 figures, Latex macros. In the final version, section 5
has been amended, the presentation has been improved, and References 21-24
have been added. Last misprints amended in Section 5 and Ref. 2
Multi-Magnon Scattering in the Ferromagnetic XXX-Model with Inhomogeneities
We determine the transition amplitude for multi-magnon scattering induced
through an inhomogeneous distribution of the coupling constant in the
ferromagnetic XXX-model. The two and three particle amplitudes are explicitely
calculated at small momenta. This suggests a rather plausible conjecture also
for a formula of the general n-particle amplitude.Comment: 21 pages, latex, no figure
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