632 research outputs found
Sibling discourses of future planning for individuals with learning disabilities: An exploration of taboo
Background: Given the enhanced life expectancy of individuals with learning disabilities, siblings are increasingly adopting caregiving responsibilities when parents are no longer able. Therefore, future care planning in families is significantly important; however, previous research highlights challenges with this process. To date, research has primarily focused on future planning from parents’ perspectives. This study explores how siblings talk about the future care planning process within the family context, attending specifically to taboo discourses. Materials and Methods: Twelve siblings of individuals with learning disabilities were interviewed about planning the future care of their brother and/or sister. The data were subsequently subject to discourse analysis. Results: Siblings were reluctant to engage in explicit future planning discussions, which drew on several taboo topics including death, conflict and obligation. Consequently, siblings employed multiple discursive strategies to evade, manage and negotiate troublesome talk. Conclusions: In addition to parents, siblings also pose a barrier to future planning. Avoidance of discussion may shield them from criticism and vulnerability, whilst also protecting familial relationships. Professionals need to recognise the challenges these conversations raise for siblings. They should endeavour to involve siblings, in order to facilitate open dialogue and collaborative future planning
Local structure of percolating gels at very low volume fractions
The formation of colloidal gels is strongly dependent on the volume fraction
of the system and the strength of the interactions between the colloids. Here
we explore very dilute solutions by the means of numerical simulations, and
show that, in the absence of hydrodynamic interactions and for sufficiently
strong interactions, percolating colloidal gels can be realised at very low
values of the volume fraction. Characterising the structure of the network of
the arrested material we find that, when reducing the volume fraction, the gels
are dominated by low-energy local structures, analogous to the isolated
clusters of the interaction potential. Changing the strength of the interaction
allows us to tune the compactness of the gel as characterised by the fractal
dimension, with low interaction strength favouring more chain-like structures
Recasting a model atomistic glassformer as a system of icosahedra
We consider a binary Lennard-Jones glassformer whose super-Arrhenius dynamics
are correlated with the formation of icosahedral structures. Upon cooling these
icosahedra organize into mesoclusters. We recast this glassformer as an
effective system of icosahedra which we describe with a population dynamics
model. This model we parameterize with data from the temperature regime
accessible to molecular dynamics simulations. We then use the model to
determine the population of icosahedra in mesoclusters at arbitrary
temperature. Using simulation data to incorporate dynamics into the model we
predict relaxation behavior at temperatures inaccessible to conventional
approaches. Our model predicts super-Arrhenius dynamics whose relaxation time
remains finite for non-zero temperature.Comment: 10 pages, 9 figure
Yielding of a Model Glassformer: an Interpretation with an Effective System of Icosahedra
We consider the yielding under simple shear of a binary Lennard-Jones
glassformer whose super-Arrhenius dynamics are correlated with the formation of
icosahedral structures. We recast this glassformer as an effective system of
icosahedra [Pinney et al. J. Chem. Phys. 143 244507 (2015)]. Looking at the
small-strain region of sheared simulations, we observe that shear rates affect
the shear localisation behavior particularly at temperatures below the glass
transition as defined with a fit to the Vogel-Fulcher-Tamman equation. At
higher temperature, shear localisation starts immediately upon shearing for all
shear rates. At lower temperatures, faster shear rates can result in a delayed
start in shear localisation; which begins close to the yield stress. Building
from a previous work which considered steady-state shear [Pinney et al. J.
Chem. Phys. 143 244507 (2016)], we interpret the response to shear and the
shear localisation in terms of a \emph{local} effective temperature with our
system of icosahedra. We find that the effective temperatures of the regions
undergoing shear localisation increase significantly with increasing strain
(before reaching a steady state plateau).Comment: 13 pages, accepted in Phys. Rev.
Non-equilibrium sedimentation of colloids on the particle scale
We investigate sedimentation of model hard sphere-like colloidal dispersions
confined in horizontal capillaries using laser scanning confocal microscopy,
dynamical density functional theory, and Brownian dynamics computer
simulations. For homogenized initial states we obtain quantitative agreement of
the results from the respective approaches for the time evolution of the
one-body density distribution and the osmotic pressure on the walls. We
demonstrate that single particle information can be obtained experimentally in
systems that were initialized further out-of-equilibrium such that complex
lateral patterns form.Comment: to be published in Phys. Rev. Let
On-chip electrically controlled routing of photons from a single quantum dot
Electrical control of on-chip routing of photons emitted by a single InAs/GaAs self-assembled quantum dot (SAQD) is demonstrated in a photonic crystal cavity-waveguide system. The SAQD is located inside an H1 cavity, which is coupled to two photonic crystal waveguides. The SAQD emission wavelength is electrically tunable by the quantum-confined Stark effect. When the SAQD emission is brought into resonance with one of two H1 cavity modes, it is preferentially routed to the waveguide to which that mode is selectively coupled. This proof of concept provides the basis for scalable, low-power, high-speed operation of single-photon routers for use in integrated quantum photonic circuits
Structure in sheared supercooled liquids:Dynamical rearrangements of an effective system of icosahedra
We consider a binary Lennard-Jones glassformer whose super-Arrhenius dynamics
are correlated with the formation of particles organized into icosahedra under
simple steady state shear. We recast this glassformer as an effective system of
icosahedra [Pinney et al. J. Chem. Phys. 143 244507 (2015)]. From the observed
population of icosahedra in each steady state, we obtain an effective
temperature which is linearly dependent on the shear rate in the range
considered. Upon shear banding, the system separates into a region of high
shear rate and a region of low shear rate. The effective temperatures obtained
in each case show that the low shear regions correspond to a significantly
lower temperature than the high shear regions. Taking a weighted average of the
effective temperature of these regions (weight determined by region size)
yields an estimate of the effective temperature which compares well with an
effective temperature based on the global mesocluster population of the whole
system.Comment: accepted by J. Chehm. Phy
Path-dependent initialization of a single quantum dot exciton spin in a nanophotonic waveguide
We demonstrate a scheme for in-plane initialization of a single exciton spin in an InGaAs quantum dot (QD) coupled to a GaAs nanobeam waveguide. The chiral coupling of the QD and the optical mode of the nanobeam enables spin initialization fidelity approaching unity in magnetic field B=1 T and >0.9 without the field. We further show that this in-plane excitation scheme is independent of the incident excitation laser polarization and depends solely on the excitation direction. This scheme provides a robust in-plane spin excitation basis for a photon-mediated spin network for quantum information applications
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