4,240 research outputs found
A unified approach to compute foliations, inertial manifolds, and tracking initial conditions
Several algorithms are presented for the accurate computation of the leaves
in the foliation of an ODE near a hyperbolic fixed point. They are variations
of a contraction mapping method in [25] to compute inertial manifolds, which
represents a particular leaf in the unstable foliation. Such a mapping is
combined with one for the leaf in the stable foliation to compute the tracking
initial condition for a given solution. The algorithms are demonstrated on the
Kuramoto-Sivashinsky equation
The development of direct payments in the UK: implications for social justice
Direct payments have been heralded by the disability movement as an important means to
achieving independent living and hence greater social justice for disabled people through
enhanced recognition as well as financial redistribution. Drawing on data from the ESRC
funded project Disabled People and Direct Payments: A UK Comparative Perspective,
this paper presents an analysis of policy and official statistics on use of direct payments
across the UK. It is argued that the potential of direct payments has only partly been
realised as a result of very low and uneven uptake within and between different parts
of the UK. This is accounted for in part by resistance from some Labour-controlled local
authorities, which regard direct payments as a threat to public sector jobs. In addition,
access to direct payments has been uneven across impairment groups. However, from a
very low base there has been a rapid expansion in the use of direct payments over the
past three years. The extent to which direct payments are able to facilitate the ultimate
goal of independent living for disabled people requires careful monitoring
Online Learning Diaries: The Voices of Allied Health Students During Covid-19 Pandemic
The COVID-19 pandemic has brought an exceptional transformation in the education system worldwide. Literature indicated the impact of COVID-19 on students’ online learning experience, yet there is limited study on the online learning experience of allied health students. Thus, the study explored the online learning experience of allied health students. The study utilized the qualitative research method. Thirteen respondents participated in the study and were selected using snowball and purposive sampling methods. A semi-structured interview was done to obtain relevant information about the study. Thematic analysis was used to analyze the collected data. The result of the study revealed that students have positive and negative experiences in online learning. Positive experiences include flexible learning opportunities and fosters learning opportunities, while negative experiences include technological factors, teacher factors, student factors, and health factors. The study revealed that the participants used the coping mechanisms: student’s self-efficacy: optimism and time management, staying connected with God, supporting the system, and social and recreational activities. The impact of the online learning experience on their career development includes inadequate clinical competence, worries about the future outcome, and traditional vs. online learning preference. Despite the accessibility and popularity of online learning in today’s world, the study found that allied health students had yet to recognize its value in their professional development.
Keywords: skills-based, clinical learning environment, coping strategie
Technical challenges for FLASH proton therapy
There is growing interest in the radiotherapy community in the application of FLASH radiotherapy, wherein the dose is delivered to the entire treatment volume in less than a second. Early pre-clinical evidence suggests that these extremely high dose rates provide significant sparing of healthy tissue compared to conventional radiotherapy without reducing the damage to cancerous cells. This interest has been reflected in the proton therapy community, with early tests indicating that the FLASH effect is also present with high dose rate proton irradiation.
In order to deliver clinically relevant doses at FLASH dose rates significant technical hurdles must be overcome in the accelerator technology before FLASH proton therapy can be realised. Of these challenges, increasing the average current from the present clinical range of 1–10 nA to in excess of 100 nA is at least feasible with existing technology, while the necessity for rapid energy adjustment on the order of a few milliseconds is much more challenging, particularly for synchrotron-based systems. However, the greatest challenge is to implement full pencil beam scanning, where scanning speeds 2 orders of magnitude faster than the existing state-of-the-art will be necessary, along with similar improvements in the speed and accuracy of associated dosimetry. Hybrid systems utilising 3D-printed patient specific range modulators present the most likely route to clinical delivery. However, to correctly adapt and develop existing technology to meet the challenges of FLASH, more pre-clinical studies are needed to properly establish the beam parameters that are necessary to produce the FLASH effect
Hyperbolicity and the effective dimension of spatially-extended dissipative systems
We show, using covariant Lyapunov vectors, that the chaotic solutions of
spatially extended dissipative systems evolve within a manifold spanned by a
finite number of physical modes hyperbolically isolated from a set of residual
degrees of freedom, themselves individually isolated from each other. In the
context of dissipative partial differential equations, our results imply that a
faithful numerical integration needs to incorporate at least all physical modes
and that increasing the resolution merely increases the number of isolated
modes.Comment: 4 pages, 4 figure
Demonstration of the Zero-Crossing Phasemeter with a LISA Test-bed Interferometer
The Laser Interferometer Space Antenna (LISA) is being designed to detect and
study in detail gravitational waves from sources throughout the Universe such
as massive black hole binaries. The conceptual formulation of the LISA
space-borne gravitational wave detector is now well developed. The
interferometric measurements between the sciencecraft remain one of the most
important technological and scientific design areas for the mission.
Our work has concentrated on developing the interferometric technologies to
create a LISA-like optical signal and to measure the phase of that signal using
commercially available instruments. One of the most important goals of this
research is to demonstrate the LISA phase timing and phase reconstruction for a
LISA-like fringe signal, in the case of a high fringe rate and a low signal
level. We present current results of a test-bed interferometer designed to
produce an optical LISA-like fringe signal previously discussed in the
literature.Comment: find minor corrections in the CQG versio
Incorrect dosage of IQSEC2, a known intellectual disability and epilepsy gene, disrupts dendritic spine morphogenesis
There is considerable genetic and phenotypic heterogeneity associated with intellectual disability (ID), specific learning disabilities, attention-deficit hyperactivity disorder, autism and epilepsy. The intelligence quotient (IQ) motif and SEC7 domain containing protein 2 gene (IQSEC2) is located on the X-chromosome and harbors mutations that contribute to non-syndromic ID with and without early-onset seizure phenotypes in both sexes. Although IQ and Sec7 domain mutations lead to partial loss of IQSEC2 enzymatic activity, the in vivo pathogenesis resulting from these mutations is not known. Here we reveal that IQSEC2 has a key role in dendritic spine morphology. Partial loss-of-function mutations were modeled using a lentiviral short hairpin RNA (shRNA) approach, which achieved a 57% knockdown of Iqsec2 expression in primary hippocampal cell cultures from mice. Investigating gross morphological parameters after 8 days of in vitro culture (8DIV) identified a 32% reduction in primary axon length, in contrast to a 27% and 31% increase in the number and complexity of dendrites protruding from the cell body, respectively. This increase in dendritic complexity and spread was carried through dendritic spine development, with a 34% increase in the number of protrusions per dendritic segment compared with controls at 15DIV. Although the number of dendritic spines had normalized by 21DIV, a reduction was noted in the number of immature spines. In contrast, when modeling increased dosage, overexpression of wild-type IQSEC2 led to neurons with shorter axons that were more compact and displayed simpler dendritic branching. Disturbances to dendritic morphology due to knockdown of Iqsec2 were recapitulated in neurons from Iqsec2 knockout mice generated in our laboratory using CRISPR/Cas9 technology. These observations provide evidence of dosage sensitivity for IQSEC2, which normally escapes X-inactivation in females, and links these disturbances in expression to alterations in the morphology of developing neurons.SJ Hinze, MR Jackson, S Lie, L Jolly, M Field, SC Barry, RJ Harvey and C Shoubridg
LUX -- A Laser-Plasma Driven Undulator Beamline
The LUX beamline is a novel type of laser-plasma accelerator. Building on the
joint expertise of the University of Hamburg and DESY the beamline was
carefully designed to combine state-of-the-art expertise in laser-plasma
acceleration with the latest advances in accelerator technology and beam
diagnostics. LUX introduces a paradigm change moving from single-shot
demonstration experiments towards available, stable and controllable
accelerator operation. Here, we discuss the general design concepts of LUX and
present first critical milestones that have recently been achieved, including
the generation of electron beams at the repetition rate of up to 5 Hz with
energies above 600 MeV and the generation of spontaneous undulator radiation at
a wavelength well below 9 nm.Comment: submitte
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