329 research outputs found
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Unforgetting Hillsborough: researching memorialisation
This poster was presented at the 'X-Scapes: 10th Linguistic Landscapes Workshop, 02-04 May, 2018, University of Bern, Switzerland', It presented ongoing research into the memorialisation of the Hillsborough Football Tragedy (15 April, 1989) in which 96 Liverpool Football fans were unlawfully killed. It explores the notion of 'unforgetting', that is replacing a false narrative with a true account, and investighates this through and as “a nexus of trajectories shaped by the ongoing interventions of inter alia individuals, institutions, activist groups, artists, passers-by etc. producing their accounts, artefacts, transgressive emplacements and acts of unforgettting across different places, media and timescales"
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Practical Ways to Support New Arrivals
The aim of this book is to provide practical advice on how best to support newly arrived bilingual pupils. As chance would have it, I began writing this introduction the day after it was announced in the Queen’s Speech to Parliament in 2004 that asylum-seekers may be subject to electronic tagging and that those who do not leave the country when their application for asylum is rejected will lose all entitlement to benefits, which may mean their children will be taken into care. It was not a good time to be a ‘new arrival’ in the UK
An approach for solving the boundary free edge difficulties in SPH modelling: application to a viscous accretion disc in close binaries
In this work, we propose a SPH interpolating Kernel reformulation suitable
also to treat free edge boundaries in the computational domain. Application to
both inviscid and viscous stationary low compressibility accretion disc models
in Close Binaries (CB) are shown. The investigation carried out in this paper
is a consequence of the fact that a low compressibility modelling is crucial to
check numerical reliability.
Results show that physical viscosity supports a well-bound accretion disc
formation, despite the low gas compressibility, when a Gaussian-derived Kernel
(from the Error Function) is assumed, in extended particle range - whose Half
Width at Half Maximum (HWHM) is fixed to a constant value - without any
spatial restrictions on its radial interaction (hereinafter GASPHER). At the
same time, GASPHER ensures adequate particle interpolations at the boundary
free edges. Both SPH and adaptive SPH (hereinafter ASPH) methods lack accuracy
if there are not constraints on the boundary conditions, in particular at the
edge of the particle envelope: Free Edge (FE) conditions. In SPH, an
inefficient particle interpolation involves a few neighbour particles; instead,
in the second case, non-physical effects involve both the boundary layer
particles themselves and the radial transport.
Either in a regime where FE conditions involve the computational domain, or
in a viscous fluid dynamics, or both, a GASPHER scheme can be rightly adopted
in such troublesome physical regimes. Despite the applied low compressibiity
condition, viscous GASPHER model shows clear spiral pattern profiles
demonstrating the better quality of results compared to SPH viscous ones.
Moreover a successful comparison of results concerning GASPHER 1D inviscid
shock tube with analytical solution is also reported.Comment: 18 pages, 12 figure
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Defining a Role: The EAL Teacher in Maths
This paper was published as part of the 'Occasional Papers' series (#12) by the National Association for Language Development in the Curriculum (NALDIC) - the UK's professional association for people working with English as an Additional Language (EAL) learners in schools.
The paper discusses how EAL specialists can work effectively alongside mathematics teachers in the mainstream classroom. It identifies salient features of the mathematics register, and how EAL and mathematics teachers can work together to develop a linguistically principled curriculum to support bilingual learners in the mathematics classroom
An approach to the Riemann problem in the light of a reformulation of the state equation for SPH inviscid ideal flows: a highlight on spiral hydrodynamics in accretion discs
In physically inviscid fluid dynamics, "shock capturing" methods adopt either
an artificial viscosity contribution or an appropriate Riemann solver
algorithm. These techniques are necessary to solve the strictly hyperbolic
Euler equations if flow discontinuities (the Riemann problem) are to be solved.
A necessary dissipation is normally used in such cases. An explicit artificial
viscosity contribution is normally adopted to smooth out spurious heating and
to treat transport phenomena. Such a treatment of inviscid flows is also widely
adopted in the Smooth Particle Hydrodynamics (SPH) finite volume free
Lagrangian scheme. In other cases, the intrinsic dissipation of Godunov-type
methods is implicitly useful. Instead "shock tracking" methods normally use the
Rankine-Hugoniot jump conditions to solve such problems. A simple, effective
solution of the Riemann problem in inviscid ideal gases is here proposed, based
on an empirical reformulation of the equation of state (EoS) in the Euler
equations in fluid dynamics, whose limit for a motionless gas coincides with
the classical EoS of ideal gases. The application of such an effective solution
to the Riemann problem excludes any dependence, in the transport phenomena, on
particle smoothing resolution length in non viscous SPH flows. Results on
1D shock tube tests, as well as examples of application for 2D turbulence and
2D shear flows are here shown. As an astrophysical application, a much better
identification of spiral structures in accretion discs in a close binary (CB),
as a result of this reformulation is also shown here.Comment: 19 pages, 17 figure
European association of echocardiography recommandations for standardization of performance, digital staorage and reporting of echocardiographic studies
peer reviewedIn view of the European Association of Echocardiography (EAE) mission statement “To promote excellence in clinical diagnosis, research, technical development, and education in cardiovascular ultrasound in Europe” and the increasing demand for standardization and quality control, the EAE have established recommendations and guidelines for standardization of echocardiography performance, data acquisition (images, measurements and morphologic descriptors), digital storage and reporting of echocardiographic studies. The aim of these recommendations is to provide a European consensus document on the minimum acceptable requirements for the clinical practice of echocardiography today and thus improve the quality and consistency of echocardiographic practice in Europe
Accretion disc dynamics in extreme mass ratio compact binaries
An analysis is presented of a numerical investigation of the dynamics and
geometry of accretion discs in binary systems with mass ratios q < 0.1,
applicable to ultra-compact X-ray binaries, AM CVn stars and very short period
cataclysmic variables. The steady-state geometry of the disc in the binary
reference frame is found to be quite different from that expected at higher
mass ratios. For q ~ 0.1, the disc takes on the usual elliptical shape, with
the major axis aligned perpendicular to the line of centres of the two stars.
However, at smaller mass ratios the elliptical gaseous orbits in the outer
regions of the disc are rotated in the binary plane. The angle of rotation
increases with gas temperature, but is found to vary inversely with q. At q =
0.01, the major axis of these orbits is aligned almost parallel to the line of
centres of the two stars. These effects may be responsible for the similar disc
structure inferred from Doppler tomography of the AM CVn star GP Com
(Morales-Rueda et al. 2003), which has q = 0.02. The steady-state geometry at
low mass ratios is not predicted by an inviscid, restricted three-body model of
gaseous orbits; it is related to the effects of tidal-viscous truncation of the
disc near the Roche lobe boundary. Since the disc geometry can be inferred
observationally for some systems, it is proposed that this may offer a useful
diagnostic for the determination of mass ratios in ultra-compact binaries.Comment: 17 pages, 9 figures, 7 in colour. Accepted for publication in MNRAS.
Plain article formatting to get round arXiv problems with mn2e.st
Local simulations of the magnetized Kelvin-Helmholtz instability in neutron-star mergers
Context. Global MHD simulations show Kelvin-Helmholtz (KH) instabilities at
the contact surface of two merging neutron stars. That region has been
identified as the site of efficient amplification of magnetic fields. However,
these global simulations, due to numerical limitations, were unable to
determine the saturation level of the field strength, and thus the possible
back-reaction of the magnetic field onto the flow. Aims. We investigate the
amplification of initially weak fields in KH unstable shear flows, and the
back-reaction of the field onto the flow. Methods. We use a high-resolution
ideal MHD code to perform 2D and 3D local simulations of shear flows. Results.
In 2D, the magnetic field is amplified in less than 0.01ms until it reaches
locally equipartition with the kinetic energy. Subsequently, it saturates due
to resistive instabilities that disrupt the KH vortex and decelerate the shear
flow on a secular time scale. We determine scaling laws of the field
amplification with the initial field strength and the grid resolution. In 3D,
this hydromagnetic mechanism may be dominated by purely hydrodynamic
instabilities limiting the amplification. We find maximum magnetic fields of
10^16 G locally, and r.m.s. maxima within the box of 10^15 G. However, such
strong fields exist only for a short period. In the saturated state, the
magnetic field is mainly oriented parallel to the shear flow for strong initial
fields, while weaker initial fields tend to lead to a more balanced
distribution of the field energy. In all models the flow shows small-scale
features. The magnetic field is at most in equipartition with the decaying
shear flow. (abridged)Comment: 26 pages, 22 figures (figure quality reduced); accepted for
publication in Astronomy & Astrophysic
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