524 research outputs found

    Online Initial Teacher Education in Australia: Affordances for Pedagogy, Practice and Outcomes

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    This paper reports on interviews with 19 senior teacher educators from 18 universities across Australia who offer fully online courses in initial teacher education (ITE). Teacher educators provided insight into four focus areas related to online ITE: 1) institutional practices; 2) affordances; 3) challenges; and 4) research priorities. Analysis revealed teacher educators perceived that online ITE can not only match on campus delivery but is also able to respond to reform agendas in ITE, including attracting students with attributes and characteristics that are likely to see them succeed as teachers, enabling students to experience contemporary approaches to learning, building strong partnerships between schools and universities, and helping address teacher shortages in rural/regional areas

    Time scales of melt extraction revealed by distribution of lava composition across a ridge axis

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    International audienceTemporal fluctuations of magmatic processes during the last 800 kyr have been investigated for the slow spreading Central Indian Ridge. The fluctuations are recorded by variations in lava chemistry along a 40 km long profile across the ridge. The temporal relations of the basalts were accurately restored using magnetic microanomalies. We report on the occurrence of ancient lavas enriched in incompatible elements whereas on-axis samples are typical normal mid-ocean ridge basalts. The enriched lavas are symmetrically distributed on either side of the ridge, implying that enriched melts reached the seafloor at intervals of about 150–200 kyr. This periodicity is viewed as a characteristic time scale in the aggregation processes of the melts produced from a heterogeneous mantle source. Geochemical variations of zero-age mid-ocean ridge basalts may primarily reflect such periodic processes rather than the spatial distribution of mantle heterogeneities

    The Okavango giant mafic dyke swarm (NE Botswana): its structural significance within the Karoo Large Igneous Province

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    The structural organization of a giant mafic dyke swarm, the Okavango complex, in the northern Karoo Large Igneous Province (LIP) of NE Botswana is detailed. This N110E-oriented dyke swarm extends for 1500 km with a maximum width of 100 km through Archaean basement terranes and Permo-Jurassic sedimentary sequences. The cornerstone of the study is the quantitative analysis of N>170 (exposed) and N>420 (detected by ground magnetics) dykes evidenced on a ca. 80-km-long section lying in crystalline host-rocks, at high-angle to the densest zone of the swarm (Shashe area). Individual dykes are generally sub-vertical and parallel to the entire swarm. Statistical analysis of width data indicates anomalous dyke frequency (few data <5.0 m) and mean dyke thickness (high value of 17 m) with respect to values classically obtained from other giant swarms. Variations of mean dyke thicknesses from 17 (N110E swarm) to 27 m (adjoining and coeval N70E giant swarm) are assigned to the conditions hosting fracture networks dilated as either shear or pure extensional structures, respectively, in response to an inferred NNW?SSE extension. Both fracture patterns are regarded as inherited brittle basement fabrics associated with a previous (Proterozoic) dyking event. The Okavango N110E dyke swarm is thus a polyphase intrusive system in which total dilation caused by Karoo dykes (estimated frequency of 87%) is 12.2% (6315 m of cumulative dyke width) throughout the 52-km-long projected Shashe section. Assuming that Karoo mafic dyke swarms in NE Botswana follow inherited Proterozoic fractures, as similarly applied for most of the nearly synchronous giant dyke complexes converging towards the Nuanetsi area, leads us to consider that the resulting triple junction-like dyke/fracture pattern is not a definitive proof for a deep mantle plume in the Karoo LIP

    Malaria Clusters among Illegal Chinese Immigrants to Europe through Africa

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    Between November 2002 and March 2003, 17 cases of malaria (1 fatal) were observed in illegal Chinese immigrants who traveled to Italy through Africa. A further cluster of 12 was reported in August, 2002. Several immigrants traveled by air, making the risk of introducing sudden acute respiratory syndrome a possibility should such illegal immigrations continue

    Methylation of class II transactivator gene promoter IV is not associated with susceptibility to Multiple Sclerosis

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    <p>Abstract</p> <p>Background</p> <p>Multiple sclerosis (MS) is a complex trait in which alleles at or near the class II loci <it>HLA-DRB1 </it>and <it>HLA-DQB1 </it>contribute significantly to genetic risk. The MHC class II transactivator (<it>MHC2TA</it>) is the master controller of expression of class II genes, and methylation of the promoter of this gene has been previously been shown to alter its function. In this study we sought to assess whether or not methylation of the <it>MHC2TA </it>promoter pIV could contribute to MS disease aetiology.</p> <p>Methods</p> <p>In DNA from peripheral blood mononuclear cells from a sample of 50 monozygotic disease discordant MS twins the <it>MHC2TA </it>promoter IV was sequenced and analysed by methylation specific PCR.</p> <p>Results</p> <p>No methylation or sequence variation of the <it>MHC2TA </it>promoter pIV was found.</p> <p>Conclusion</p> <p>The results of this study cannot support the notion that methylation of the pIV promoter of <it>MHC2TA </it>contributes to MS disease risk, although tissue and timing specific epigenetic modifications cannot be ruled out.</p

    Active oceanic spreading in the northern north Fiji basin : results of the NOFI cruise of R/V l'Atalante (Newstarmer project)

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    The South Pandora and the Tripartite Ridges are active spreading centers located in the northern part of the North Fiji Basin. These spreading centers were surveyed over a distance of 750 km during the NOFI cruise of R/V L'Atalante (August-September 1994) which was conducted in the frame of the french-japanese Newstarmer cooperation project. SIMRAD EM12-dual full coverage swath bathymetric and imagery data as well as airgun 6-channel seismic, magnetics and gravity profiles were recorded along an off-axis from 170°40'E to 178°E. Dredging and piston coring were also performed along and off-axis. The axial domain of the South Pandora Ridge is divided into 5 first-order segments characterized by contrasted morphologies. The average width of the active domain is 20 km and corresponds either to bathymetric highs or to deep elongated grabens. The bathymetric highs are volcanic constructions, locally faulted and rifted, which can obstruct totally the axial valley. The grabens show the typical morphology of slow spreading axes, with two steep walls flanking a deep axial valley. Elongated lateral ridges may be present on both sides of the grabens. Numerous volcanoes, up to several kilometers in diameter, occur on both flanks of the South Pandora Ridge. The Tripartite Ridge consists of three main segments showing a sigmoid shape. Major changes in the direction of the active zones are observed at the segment discontinuities. These discontinuities show various geometrical patterns which suggest complex transform relay zones. Preliminary analysis of seismic reflection profiles suggest that the Tripartite Ridge is a very young feature which propagates into an older oceanic domain characterized by a significant sedimentary cover. By contrast, a very thin to absent sedimentary cover is observed about 100 km on both flanks of the South Pandora Ridge active axis. The magnetic anomaly profiles give evidence of long and continuous lineations, parallel to the South Pandora Ridge spreading axis. (Résumé d'auteur

    Transtheoretical Model-based multiple behavior intervention for weight management: Effectiveness on a population basis

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    Background: The increasing prevalence of overweight and obesity underscores the need for evidence-based, easily disseminable interventions for weight management that can be delivered on a population basis. The Transtheoretical Model (TTM) offers a promising theoretical framework for multiple behavior weight management interventions. Methods: Overweight or obese adults (BMI 25–39.9; n = 1277) were randomized to no-treatment control or home-based, stage-matched multiple behavior interventions for up to three behaviors related to weight management at 0, 3, 6, and 9 months. All participants were re-assessed at 6, 12, and 24 months. Results: Significant treatment effects were found for healthy eating (47.5% versus 34.3%), exercise (44.90% versus 38.10%), managing emotional distress (49.7% versus 30.30%), and untreated fruit and vegetable intake (48.5% versus 39.0%) progressing to Action/Maintenance at 24 months. The groups differed on weight lost at 24 months. Co-variation of behavior change occurred and was much more pronounced in the treatment group, where individuals progressing to Action/Maintenance for a single behavior were 2.5–5 times more likely to make progress on another behavior. The impact of the multiple behavior intervention was more than three times that of single behavior interventions. Conclusions: This study demonstrates the ability of TTM-based tailored feedback to improve healthy eating, exercise, managing emotional distress, and weight on a population basis. The treatment produced a high level of population impact that future multiple behavior interventions can seek to surpass

    An Extremes of outcome strategy provides evidence that multiple sclerosis severity is determined by alleles at the <i>HLA-DRB1</i> locus

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    Multiple sclerosis (MS) is a common inflammatory disease of the central nervous system unsurpassed for variability in disease outcome. A cohort of sporadic MS cases (n=63), taken from opposite extremes of the distribution of long-term outcome, was used to determine the role of the HLA-DRB1 locus on MS disease severity. Genotyping sets of benign and malignant MS patients showed that HLA-DRB1*01 was significantly underrepresented in malignant compared with benign cases. This allele appears to attenuate the progressive disability that characterizes MS in the long term. The observation was doubly replicated in (i) Sardinian benign and malignant patients and (ii) a cohort of affected sibling pairs discordant for HLA-DRB1*01. Among the latter, mean disability progression indices were significantly lower in those carrying the HLA-DRB1*01 allele compared with their disease-concordant siblings who did not. The findings were additionally supported by similar transmission distortion of HLA-DRB1*04 subtypes closely related to HLA-DRB1*01. The protective effect of HLA-DRB1*01 in sibling pairs may result from a specific epistatic interaction with the susceptibility allele HLA-DRB1*1501. A high-density (&gt;700) SNP examination of the MHC region in the benign and malignant patients could not identify variants differing significantly between the two groups, suggesting that HLA-DRB1 may itself be the disease-modifying locus. We conclude that HLA-DRB1*01, previously implicated in disease resistance, acts as an independent modifier of disease progression. These results closely link susceptibility to long-term outcome in MS, suggesting that shared quantitative MHC-based mechanisms are common to both, emphasizing the central role of this region in pathogenesis
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