819 research outputs found

    Numerical Study of Two-Dimensional Secondary Injection Into a Mach 3.5 Freestream

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    Upstream interaction within a dual-mode scramjet engine is investigated numerically. The upstream interaction is investigated by increasing the freestream-to-injector pressure ratio. The constant area duct and sudden expansion geometries are used to achieve these results. Analysis using the symmetry boundary condition is compared to the full boundary condition for the constant area duct. Numerical analysis of the Mach 3.5 freestream is conducted using normal sonic injection of nitrogen gas to create the upstream interaction. Comparisons, where applicable, are made to experimental results. Due to the high speed of the flowfield, oblique shockwaves are present causing numerical convergence difficult to achieve. The flowfield symmetry assumptions break down due to the high shear stresses present in the boundary layer separation region. As the freestream-to-injector pressure ratio is increased this separation region begins to move upstream within the isolator region. This study proves that the upstream interaction is not related to reacting flows, but rather to the high turbulent shear stresses that are present in the boundary layer separation regions

    “OASIS-F”: development of a fuzzy online assessment system

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    A web-based tutorial and examination system has been developed in the Department of Electrical and Electronic Engineering at The University of Auckland. OASIS is an Online ASsessment and Information System. OASIS comprises an extensive question database and server-side program that delivers questions to students, marks their responses and records students’ activities and performance. In OASIS skills are developed by solving practical problems, which are all marked to give instant feedback. The students can practice on these problems from any web browser at any location on or off campus. Using OASIS does not require any special application software since all of the processing is done on the web server. Since 2000 the emphasis has been on giving students core-competency and skills but in a further development of OASIS a ‘fuzzy’ marking scheme is being introduced to allow marking of ‘softer’ subject material where ‘crisp’ numerical answers are inappropriate. Thus it will be possible to assess a student’s ‘understanding’ of some topic. OASIS-fuzzy allows a consistent marking scheme for these situations by assessing the student’s ability to ‘see the wood for the trees’. In OASIS-fuzzy the system measures what is in effect the ‘centre of gravity’ of the student’s knowledge on a particular topic by assessing their ability to rank information about that topic in order of importance. This we believe to be a measure of their ‘understanding’ of the topic. This paper presents a brief description of the system, its structure and its features

    Lateral inhibition during nociceptive processing

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    Functional outcomes from a head-to-head, randomized, double-blind trial of lisdexamfetamine dimesylate and atomoxetine in children and adolescents with attention-deficit/hyperactivity disorder and an inadequate response to methylphenidate

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    Attention-deficit/hyperactivity disorder (ADHD) is associated with functional impairments in multiple domains of patients' lives. A secondary objective of this randomized, active-controlled, head-to-head, double-blind, dose-optimized clinical trial was to compare the effects of lisdexamfetamine dimesylate (LDX) and atomoxetine (ATX) on functional impairment in children and adolescents with ADHD. Patients aged 6-17 years with an ADHD Rating Scale IV total score ≄ 28 and an inadequate response to methylphenidate treatment (judged by investigators) were randomized (1:1) to once-daily LDX or ATX for 9 weeks. Parents/guardians completed the Weiss Functional Impairment Rating Scale-Parent Report (WFIRS-P) at baseline and at week 9 or early termination. p values were nominal and not corrected for multiple comparisons. Of 267 randomized patients, 200 completed the study (LDX 99, ATX 101). At baseline, mean WFIRS-P total score in the LDX group was 0.95 [standard deviation (SD) 0.474; 95% confidence interval (CI) 0.87, 1.03] and in the ATX group was 0.91 (0.513; 0.82, 1.00). Scores in all WFIRS-P domains improved from baseline to endpoint in both groups, with least-squares mean changes in total score of -0.35 (95% CI -0.42, -0.29) for LDX and -0.27 (-0.33, -0.20) for ATX. The difference between LDX and ATX was statistically significant (p < 0.05) for the Learning and School (effect size of LDX vs ATX, 0.43) and Social Activities (0.34) domains and for total score (0.27). Both treatments reduced functional impairment in children and adolescents with ADHD; LDX was statistically significantly more effective than ATX in two of six domains and in total score

    Cowhage-Induced Itch as an Experimental Model for Pruritus. A Comparative Study with Histamine-Induced Itch

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    Histamine is the prototypical pruritogen used in experimental itch induction. However, in most chronic pruritic diseases, itch is not predominantly mediated by histamine. Cowhage-induced itch, on the other hand, seems more characteristic of itch occurring in chronic pruritic diseases.We tested the validity of cowhage as an itch-inducing agent by contrasting it with the classical itch inducer, histamine, in healthy subjects and atopic dermatitis (AD) patients. We also investigated whether there was a cumulative effect when both agents were combined.Fifteen healthy individuals and fifteen AD patients were recruited. Experimental itch induction was performed in eczema-free areas on the volar aspects of the forearm, using different itch inducers: histamine, cowhage and their combination thereof. Itch intensity was assessed continuously for 5.5 minutes after stimulus application using a computer-assisted visual analogue scale (COVAS).In both healthy and AD subjects, the mean and peak intensity of itch were higher after the application of cowhage compared to histamine, and were higher after the combined application of cowhage and histamine, compared to histamine alone (p<0.0001 in all cases). Itch intensity ratings were not significantly different between healthy and AD subjects for the same itch inducer used; however AD subjects exhibited a prolonged itch response in comparison to healthy subjects (p<0.001).Cowhage induced a more intense itch sensation compared to histamine. Cowhage was the dominant factor in itch perception when both pathways were stimulated in the same time. Cowhage-induced itch is a suitable model for the study of itch in AD and other chronic pruritic diseases, and it can serve as a new model for testing antipruritic drugs in humans

    P\u3csup\u3e3\u3c/sup\u3e: Phylogenetic posterior prediction in RevBayes

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    © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. Tests of absolute model fit are crucial in model-based inference because poorly structured models can lead to biased parameter estimates. In Bayesian inference, posterior predictive simulations can be used to test absolute model fit. However, such tests have not been commonly practiced in phylogenetic inference due to a lack of convenient and flexible software. Here, we describe our newly implemented tests of model fit using posterior predictive testing, based on both data- and inference-based test statistics, in the phylogenetics software RevBayes. This new implementation makes a large spectrum of models available for use through a user-friendly and flexible interface

    Remote assessment of ADHD in children and adolescents: recommendations from the European ADHD Guidelines Group following the clinical experience during the COVID-19 pandemic

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    Adolescents; COVID-19; Remote assessmentAdolescents; COVID-19; AvaluaciĂł a distĂ nciaAdolescentes; COVID-19; EvaluaciĂłn a distanciaThe COVID-19 pandemic led ADHD services to modify the clinical practice to reduce in-person contact as much as possible to minimise viral spread. This had far-reaching effects on day-to-day clinical practice as remote assessments were widely adopted. Despite the attenuation of the acute threat from COVID, many clinical services are retaining some remote practices. The lack of clear evidence-based guidance about the most appropriate way to conduct remote assessments meant that these changes were typically implemented in a localised, ad hoc, and un-coordinated way. Here, the European ADHD Guidelines Group (EAGG) discusses the strengths and weaknesses of remote assessment methods of children and adolescents with ADHD in a narrative review based on available data and expert opinions to highlight key recommendations for future studies and clinical practice. We conclude that going forward, despite remote working in clinical services functioning adequately during the pandemic, all required components of ADHD assessment should still be completed following national/international guidelines; however, the process may need adaptation. Social restrictions, including changes in education provision, can either mask or exacerbate features associated with ADHD and therefore assessment should carefully chart symptom profile and impairment prior to, as well as during an ongoing pandemic. While remote assessments are valuable in allowing clinical services to continue despite restrictions and may have benefits for routine care in the post-pandemic world, particular attention must be paid to those who may be at high risk but not be able to use/access remote technologies and prioritize these groups for conventional face-to-face assessments

    Distinct domains of erythroid Kruppel-like factor modulate chromatin remodeling and transactivation at the endogenous beta-globin gene promoter

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    Characterization of the mechanism(s) of action of trans-acting factors in higher eukaryotes requires the establishment of cellular models that test their function at endogenous target gene regulatory elements. Erythroid Kruppel-like factor (EKLF) is essential for beta -globin gene transcription. To elucidate the in vivo determinants leading to transcription of the adult beta -globin gene, functional domains of EKLF were examined in the context of chromatin remodeling and transcriptional activation at the endogenous locus. Human EKLF (hEKLF) sequences, linked to an estrogen-responsive domain, were studied with an erythroblast cell line lacking endogenous EKLF expression (J2e Delta eklf). J2e Delta eklf cells transduced with hEKLF demonstrated a dose-dependent rescue of beta -globin transcription in the presence of inducing ligand. Further analysis using a series of amino-terminal truncation mutants of hEKLF identified a distinct internal domain, which is sufficient for transactivation. Interestingly, studies of the chromatin structure of the beta -promoter revealed that a smaller carboxy-terminal domain generated an open promoter configuration. In vitro and in vivo binding studies demonstrated that this region interacted with BRG1, a component of the SWI/SNF chromatin remodeling complex. However, further study revealed that BRG1 interacted with an even smaller domain of EKLF, suggesting that additional protein interactions are required for chromatin remodeling at the endogenous beta -promoter. Taken together, our findings support a stepwise process of chromatin remodeling and coactivator recruitment to the beta -globin promoter in vivo. The J2e Delta eklf inducible hEKLF system will be a valuable tool for further characterizing the temporal series of events required for endogenous beta -globin gene transcription

    Going beyond the one-off: How can STEM engagement programmes with young people have real lasting impact?

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    A major focus in the science, technology, engineering and mathematics (STEM) public engagement sector concerns engaging with young people, typically through schools. The aims of these interventions are often to positively affect students’ aspirations towards continuing STEM education and ultimately into STEM-related careers. Most school engagement activities take the form of short one-off interventions that, while able to achieve positive outcomes, are limited in the extent to which they can have lasting impacts on aspirations. In this paper, we discuss various different emerging programmes of repeated interventions with young people, assessing what impacts can realistically be expected. Short series of interventions appear also to suffer some limitations in the types of impacts achievable. However, deeper programmes that interact with both young people and those who influence them over significant periods of time (months to years) seem to be more effective in influencing aspirations. We discuss how developing a theory of change and considering young people’s wider learning ecologies are required in enabling lasting impacts in a range of areas. Finally, we raise several sector-wide challenges to implementing and evaluating these emerging approaches
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