1,348 research outputs found

    The use of narrative to provide a cohesive structure for a web based computing course

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    Narrative has long been used as an educational tool. This article explains how narrative, in the form of popular accounts, has been used to provide context, structure and broad appeal to a large-scale, entry-level university course on Information and Communication Technology (ICT). This course is delivered via the web with online tuition. Students' responses to the use of narrative and the scope of the material has been encouraging. It is argued that narrative performs an enculturation function that is often under-utilised in ICT education

    Improved primordial non-gaussianity constraints from measurements of galaxy clustering and the integrated Sachs-Wolfe effect

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    We present the strongest robust constraints on primordial non-Gaussianity (PNG) from currently available galaxy surveys, combining large-scale clustering measurements and their cross-correlations with the cosmic microwave background. We update the data sets used by Giannantonio et al. (2012), and broaden that analysis to include the full set of two-point correlation functions between all surveys. In order to obtain the most reliable constraints on PNG, we advocate the use of the cross-correlations between the catalogs as a robust estimator and we perform an extended analysis of the possible systematics to reduce their impact on the results. To minimize the impact of stellar contamination in our luminous red galaxy (LRG) sample, we use the recent Baryon Oscillations Spectroscopic Survey catalog of Ross et al. (2011). We also find evidence for a new systematic in the NVSS radio galaxy survey similar to, but smaller than, the known declination-dependent issue; this is difficult to remove without affecting the inferred PNG signal, and thus we do not include the NVSS auto-correlation function in our analyses. We find no evidence of primordial non-Gaussianity; for the local-type configuration we obtain for the skewness parameter −36<fNL<45 -36 < f_{\mathrm{NL}} < 45 at 95 % c.l. (5±215 \pm 21 at 1σ1\sigma) when using the most conservative part of our data set, improving previous results; we also find no evidence for significant kurtosis, parameterized by gNLg_{\mathrm{NL}}. In addition to PNG, we simultaneously constrain dark energy and find that it is required with a form consistent with a cosmological constant.Comment: 24 pages, 16 figures. More conservative treatment of the NVSS data, version accepted by Phys. Rev.

    Temporal muscle thickness is an independent prognostic marker in patients with progressive glioblastoma: translational imaging analysis of the EORTC 26101 trial

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    BACKGROUND: Temporal muscle thickness (TMT) was described as surrogate marker of skeletal muscle mass. This study aimed to evaluate the prognostic relevance of TMT in patients with progressive glioblastoma. METHODS: TMT was analyzed on cranial magnetic resonance images of 596 patients with progression of glioblastoma after radio-chemotherapy enrolled in the EORTC 26101 trial. An optimal TMT cutoff for overall survival (OS) and progression free survival (PFS) was defined in the training cohort (n=260, phase 2). Patients were grouped as "below" or "above" the TMT cutoff and associations with OS and PFS were tested using the Cox model adjusted for important risk factors. Findings were validated in a test cohort (n=308, phase 3). RESULTS: An optimal baseline TMT cutoff of 7.2 mm was obtained in the training cohort for both OS and PFS (AUC=0.64). Univariate analyses estimated a hazard ratio (HR) of 0.54 (95% CI: 0.42, 0.70, p<0.0001) for OS and a HR of 0.49 (95% CI: 0.38, 0.64, p<0.0001) for PFS for the comparison of training cohort patients above versus below the TMT cutoff. Similar results were obtained in Cox models adjusted for important risk factors with relevance in the trial for OS (HR of 0.54, 95% CI: 0.41, 0.70, p<0.0001) and PFS (HR of 0.47, 95% CI: 0.36, 0.61, p<0.0001). Results were confirmed in the validation cohort. CONCLUSION: Reduced TMT is an independent negative prognostic parameter in patients with progressive glioblastoma and may help to facilitate patient management by supporting patient stratification for therapeutic interventions or clinical trials

    Adjuvant and concurrent temozolomide for 1p/19q non-co-deleted anaplastic glioma (CATNON; EORTC study 26053-22054): second interim analysis of a randomised, open-label, phase 3 study

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    BACKGROUND The CATNON trial investigated the addition of concurrent, adjuvant, and both current and adjuvant temozolomide to radiotherapy in adults with newly diagnosed 1p/19q non-co-deleted anaplastic gliomas. The benefit of concurrent temozolomide chemotherapy and relevance of mutations in the IDH1 and IDH2 genes remain unclear. METHODS This randomised, open-label, phase 3 study done in 137 institutions across Australia, Europe, and North America included patients aged 18 years or older with newly diagnosed 1p/19q non-co-deleted anaplastic gliomas and a WHO performance status of 0-2. Patients were randomly assigned (1:1:1:1) centrally using a minimisation technique to radiotherapy alone (59·4 Gy in 33 fractions; three-dimensional conformal radiotherapy or intensity-modulated radiotherapy), radiotherapy with concurrent oral temozolomide (75 mg/m2^{2} per day), radiotherapy with adjuvant oral temozolomide (12 4-week cycles of 150-200 mg/m2^{2} temozolomide given on days 1-5), or radiotherapy with both concurrent and adjuvant temozolomide. Patients were stratified by institution, WHO performance status score, age, 1p loss of heterozygosity, the presence of oligodendroglial elements on microscopy, and MGMT promoter methylation status. The primary endpoint was overall survival adjusted by stratification factors at randomisation in the intention-to-treat population. A second interim analysis requested by the independent data monitoring committee was planned when two-thirds of total required events were observed to test superiority or futility of concurrent temozolomide. This study is registered with ClinicalTrials.gov, NCT00626990. FINDINGS Between Dec 4, 2007, and Sept 11, 2015, 751 patients were randomly assigned (189 to radiotherapy alone, 188 to radiotherapy with concurrent temozolomide, 186 to radiotherapy and adjuvant temozolomide, and 188 to radiotherapy with concurrent and adjuvant temozolomide). Median follow-up was 55·7 months (IQR 41·0-77·3). The second interim analysis declared futility of concurrent temozolomide (median overall survival was 66·9 months [95% CI 45·7-82·3] with concurrent temozolomide vs 60·4 months [45·7-71·5] without concurrent temozolomide; hazard ratio [HR] 0·97 [99·1% CI 0·73-1·28], p=0·76). By contrast, adjuvant temozolomide improved overall survival compared with no adjuvant temozolomide (median overall survival 82·3 months [95% CI 67·2-116·6] vs 46·9 months [37·9-56·9]; HR 0·64 [95% CI 0·52-0·79], p<0·0001). The most frequent grade 3 and 4 toxicities were haematological, occurring in no patients in the radiotherapy only group, 16 (9%) of 185 patients in the concurrent temozolomide group, and 55 (15%) of 368 patients in both groups with adjuvant temozolomide. No treatment-related deaths were reported. INTERPRETATION Adjuvant temozolomide chemotherapy, but not concurrent temozolomide chemotherapy, was associated with a survival benefit in patients with 1p/19q non-co-deleted anaplastic glioma. Clinical benefit was dependent on IDH1 and IDH2 mutational status. FUNDING Merck Sharpe & Dohme

    Using learning environments as a metaphor for educational change

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    Purpose – The purpose of this paper is to show that the online learning environment can be seen as the means by which higher education can explore the challenges and opportunities raised by online and digital society. Design/methodology/approach – The paper argues that the online learning environment can be seen as a metaphor for how universities respond to the requirements and challenges of the digital age. Current learning management systems (LMSs) are examined, and compared with the values found in web 2.0 and social media. Current thinking on pedagogy for online learning is then examined. The SocialLearn project at the Open University in the UK is then explained, which seeks to create a disaggregated, decentralised, social system for learners. Findings – The conclusion from the analysis is that there is a conflict between the centralised learning management system (LMS) and the requirements of online pedagogy. The traditional LMS can be seen as embodying the wrong metaphor, that of the traditional classroom. The paper concludes by arguing that such learning environments will be more useful to higher education in coming to understand its response to many of the changes being seen in society, which are facilitated by the new technologies. Originality/value – The paper provides a framework for considering LMSs and their relation to universities and pedagogy, and an argument for the promotion of more decentralised systems

    Issues in joint SZ and optical cluster finding

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    We apply simple optical and SZ cluster finders to mock galaxy catalogues and SZ flux maps created from dark matter halos in a (1 Gpc/h)^3 dark matter simulation, at redshifts 0.5 and 0.9. At each redshift, the two catalogues are then combined to assess how well they can improve each other, and compared to several variants of catalogues made using SZ flux and galaxy information simultaneously. We use several different criteria to compare the catalogues, and illustrate some of the tradeoffs which arise in tuning the galaxy cluster finders with respect to these criteria. We detail many of the resulting improvements and issues which arise in comparing and combining these two types of data sets.Comment: 14 pages, added information thanks to helpful suggestions from refere

    ESTRO-EANO guideline on target delineation and radiotherapy details for glioblastoma

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    BACKGROUND AND PURPOSE Target delineation in glioblastoma is still a matter of extensive research and debate. This guideline aims to update the existing joint European consensus on delineation of the clinical target volume (CTV) in adult glioblastoma patients. MATERIAL AND METHODS The ESTRO Guidelines Committee identified 14 European experts in close interaction with the ESTRO clinical committee and EANO who discussed and analysed the body of evidence concerning contemporary glioblastoma target delineation, then took part in a two-step modified Delphi process to address open questions. RESULTS Several key issues were identified and are discussed including i) pre-treatment steps and immobilisation, ii) target delineation and the use of standard and novel imaging techniques, and iii) technical aspects of treatment including planning techniques and fractionation. Based on the EORTC recommendation focusing on the resection cavity and residual enhancing regions on T1-sequences with the addition of a reduced 15 mm margin, special situations are presented with corresponding potential adaptations depending on the specific clinical situation. CONCLUSIONS The EORTC consensus recommends a single clinical target volume definition based on postoperative contrast-enhanced T1 abnormalities, using isotropic margins without the need to cone down. A PTV margin based on the individual mask system and IGRT procedures available is advised; this should usually be no greater than 3 mm when using IGRT

    Thermoelectric properties of lead chalcogenide core-shell nanostructures

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    We present the full thermoelectric characterization of nanostructured bulk PbTe and PbTe-PbSe samples fabricated from colloidal core-shell nanoparticles followed by spark plasma sintering. An unusually large thermopower is found in both materials, and the possibility of energy filtering as opposed to grain boundary scattering as an explanation is discussed. A decreased Debye temperature and an increased molar specific heat are in accordance with recent predictions for nanostructured materials. On the basis of these results we propose suitable core-shell material combinations for future thermoelectric materials of large electric conductivities in combination with an increased thermopower by energy filtering.Comment: 12 pages, 8 figure
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