2,644 research outputs found
Vlasov Simulations of Trapping and Inhomogeneity in Raman Scattering
We study stimulated Raman scattering (SRS) in laser-fusion conditions with
the Eulerian Vlasov code ELVIS. Back SRS from homogeneous plasmas occurs in
sub-picosecond bursts and far exceeds linear theory. Forward SRS and re-scatter
of back SRS are also observed. The plasma wave frequency downshifts from the
linear dispersion curve, and the electron distribution shows flattening. This
is consistent with trapping and reduces the Landau damping. There is some
acoustic () activity and possibly electron acoustic scatter.
Kinetic ions do not affect SRS for early times but suppress it later on. SRS
from inhomogeneous plasmas exhibits a kinetic enhancement for long density
scale lengths. More scattering results when the pump propagates to higher as
opposed to lower density.Comment: 4 pages, 6 figures. Submitted to "Journal of Plasmas Physics" for the
conference proceedings of the 19th International Conference on Numerical
Simulation of Plasma
A Systematic Review of Behaviour-Related Outcome Assessments for Children on the Autism Spectrum with Intellectual Disabilities in Education Settings
A systematic review was completed to identify assessments used with children with intellectual disabilities to assess adaptive behaviour, challenging behaviour and autism-related behaviour and consider their appropriateness for use by special education teachers with autistic pupils. The findings of this review led to the recommendation that the Pervasive Development Disorder Behavior Inventory, Aberrant Behavior Checklist, Autism Treatment Evaluation Checklist and the Teacher Autism Progress Scale are currently the most appropriate assessments for these purposes, although some limitations of these assessments exist. Additional recommendations included teacher input during the development of robust assessments to show progress for autistic children with intellectual disabilities and further evaluation of commonly used assessments with an appropriate sample in a relevant education setting
Specialising Software for Different Downstream Applications Using Genetic Improvement and Code Transplantation
OAPA Genetic improvement uses computational search to improve existing software while retaining its partial functionality. Genetic improvement has previously been concerned with improving a system with respect to all possible usage scenarios. In this paper, we show how genetic improvement can also be used to achieve specialisation to a specific set of usage scenarios. We use genetic improvement to evolve faster versions of a C++ program, a Boolean satisfiability solver called MiniSAT, specialising it for three applications. Our specialised solvers achieve between 4% and 36% execution time improvement, which is commensurate with efficiency gains achievable using human expert optimisation for the general solver. We also use genetic improvement to evolve faster versions of an image processing tool called ImageMagick, utilising code from GraphicsMagick, another image processing tool which was forked from it. We specialise the format conversion functionality to black & amp; white images and colour images only. Our specialised versions achieve up to 3% execution time improvement
A randomised controlled trial of efficacy of cognitive rehabilitation in multiple sclerosis: a cognitive, behavioural, and MRI study
Aim: To explore the efficacy of home-based, computerised, cognitive rehabilitation in patients with multiple sclerosis using neuropsychological assessment and advanced structural and functional magnetic resonance imaging (fMRI).
Methods: 38 patients with MS and cognitive impairment on the Brief International Cognitive Assessment for MS (BICAMS) were enrolled. Patients were randomised to undergo 45 minutes of computerised cognitive rehabilitation using RehaCom software (n = 19) three times weekly for six weeks or to a control condition (n = 19). Neuropsychological and MRI data were obtained at baseline (time 1), following the 6-week intervention (time 2), and after a further twelve weeks (time 3). Cortical activations were explored using fMRI and microstructural changes were explored using quantitative magnetisation transfer (QMT) imaging.
Results: The treatment group showed a greater improvement in SDMT gain scores between baseline and time 2 compared to the control group (p = 0.005). The treatment group exhibited increased activation in the bilateral prefrontal cortex and right temporoparietal regions relative to control group at time 3 (p < 0.05FWE corrected). No significant changes were observed on QMT.
Conclusion: This study supports the hypothesis that home-based, computerised, cognitive rehabilitation may be effective in improving cognitive performance in patients with MS.
Clinical trials registration is ISRCTN54901925
Cognitive impairment among patients with multiple sclerosis:associations with employment and quality of life
OBJECTIVES
To explore the relationship between cognitive impairment and conventional measures of disability in multiple sclerosis (MS), quality of life (QOL) and employment status using the brief international cognitive assessment for multiple sclerosis (BICAMS) in the routine outpatient clinic.
METHODS
62 patients with MS were assessed on the BICAMS test battery for cognitive impairment. Data were obtained on employment status and a number of questionnaires completed including fatigue severity score, multiple sclerosis neuropsychological questionnaire, hospital anxiety and depression scale, the functional assessment of multiple sclerosis (FAMS) as well as on the EuroQOL five dimension questionnaire (EQ-5D). Other assessments include the patient activation measure and unidimensional self-efficacy scale for multiple sclerosis.
RESULTS
Cognitive assessment revealed 44 subjects (65%) had evidence of cognitive impairment on formal testing. In comparison with patients without evidence of cognitive impairment, cognitively impaired patients exhibited significantly higher rates of unemployment (p=0.009). The symbol digits modalities test was the most significant predictor of unemployment. Cognitive impairment was associated with lower QOL scores on the FAMS (p=0.001) and EQ-5D (p<0.001).
CONCLUSIONS
BICAMS provides a sensitive and easy to administer screening test for cognitive impairment within the outpatient setting. Cognitive impairment is common in our cohort of patients with MS attending outpatients and appears to be associated with increased rates of unemployment and lower measures of QOL
Production of TGF-alpha and TGF-beta by cultured keratinocytes, skin and oral squamous cell carcinomas--potential autocrine regulation of normal and malignant epithelial cell proliferation.
Transforming growth factors have a wide range of biological activities related to cell proliferation and differentiation. In general TGF-alpha promotes cell proliferation while TGF-beta may stimulate or inhibit proliferation depending on the cell type and growth factor environment. Cultured human keratinocytes, skin and oral squamous cell carcinomas were analysed for the presence of transcripts and protein for the transforming growth factors alpha & beta. Both growth factors were detected in cultured keratinocytes (which have receptors for and respond to both ligands), and in medium conditioned by these cells. Additionally transcripts for TGF-alpha were found preferentially in the basal, proliferative compartment of cultured keratinocytes. Similarly both growth factors were detected in oral squamous cell carcinomas and a highly significant inverse correlation was found between the levels of TGF-alpha and the epidermal growth factor receptor in these tumours. The data for TGF-alpha are consistent with the existence of an autocrine growth control loop influencing cell proliferation in both a normal cell type and malignant epithelial tissues, a process that in keratinocytes and responsive squamous cell carcinomas could be modulated by TGF-beta
Genetic improvement of GPU software
We survey genetic improvement (GI) of general purpose computing on graphics cards. We summarise several experiments which demonstrate four themes. Experiments with the gzip program show that genetic programming can automatically port sequential C code to parallel code. Experiments with the StereoCamera program show that GI can upgrade legacy parallel code for new hardware and software. Experiments with NiftyReg and BarraCUDA show that GI can make substantial improvements to current parallel CUDA applications. Finally, experiments with the pknotsRG program show that with semi-automated approaches, enormous speed ups can sometimes be had by growing and grafting new code with genetic programming in combination with human input
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