917 research outputs found

    ADV measurements of blockage flow effects near a model jacket in waves and current

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    Design standards for drag loading on offshore jacket structures do not presently account for the reduction in forces arising from flow blockage effects in the event of combined waves and current. This force reduction is believed to originate in reduced mean flow velocity through the jacket, but this has never been directly measured. To address this, we conducted physical-model tests which measured the flow adjacent to a jacket structure in combined waves and in-line currents using acoustic Doppler velocimeters. Results confirm a dramatic reduction in the mean flow velocity up-wave and down-wave of a model jacket in waves and current, far greater than the flow reduction observed in current alone. These results unambiguously confirm the significant additional blockage (and hence reduction in structural loads) not captured in current offshore design standards

    Eosinophil-Mediated Immune Control of Adult Filarial Nematode Infection Can Proceed in the Absence of IL-4 Receptor Signaling

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    Helminth infections are accompanied by eosinophilia in parasitized tissues. Eosinophils are effectors of immunity to tissue helminths. We previously reported that in the context of experimental ļ¬larial nematode infection, optimum tissue eosinophil recruitment was coordinated by local macrophage populations following IL-4Rā€“dependent in situ proliferation and alternative activation. However, in the current study, we identify that control of chronic adult ļ¬larial worm infection is evident in IL-4Raā€“deļ¬cient (IL-4Ra2/2) mice, whereby the majority of infections do not achieve patency. An associated residual eosinophilia was apparent in infected IL-4Ra2/2 mice. By treating IL-4Ra2/2 mice serially with anti-CCR3 Ab or introducing a compound deļ¬ciency in CCR3 within IL-4Ra2/2 mice, residual eosinophilia was ablated, and susceptibility to chronic adult Brugia malayi infection was established, promoting a functional role for CCR3-dependent eosinophil inļ¬‚ux in immune control in the absence of IL-4/IL13ā€“dependent immune mechanisms. We investigated additional cytokine signals involved in residual eosinophilia in the absence IL-4Ra signaling and deļ¬ned that IL-4Ra2/2/IL-52/2 double-knockout mice displayed signiļ¬cant eosinophil deļ¬ciency compared with IL-4Ra2/2 mice and were susceptible to chronic fecund adult ļ¬larial infections. Contrastingly, there was no evidence that either IL-4Rā€“dependent or IL-4Rā€“independent/CCR3/IL-5ā€“dependent immunity inļ¬‚uenced B. malayi microļ¬larial loads in the blood. Our data demonstrate multiplicity of Th2-cytokine control of eosinophil tissue recruitment during chronic ļ¬larial infection and that IL-4Rā€“independent/IL-5ā€“ and CCR3-dependent pathways are sufļ¬cient to control ļ¬larial adult infection via an eosinophil-dependent effector response prior to patency

    Displaced but not replaced: the impact of e-learning on academic identities in higher education.

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    Challenges facing universities are leading many to implement institutional strategies to incorporate e-learning rather than leaving its adoption up to enthusiastic individuals. Although there is growing understanding about the impact of e-learning on the student experience, there is less understanding of academicsā€™ perceptions of e-learning and its impact on their identities. This paper explores the changing nature of academic identities revealed through case study research into the implementation of e-learning at one UK university. By providing insight into the lived experiences of academics in a university in which technology is not only transforming access to knowledge but also influencing the balance of power between academic and student in knowledge production and use, it is suggested that academics may experience a jolt to their ā€˜trajectory of selfā€™ when engaging with e-learning. The potential for e-learning to prompt loss of teacher presence and displacement as knowledge expert may appear to undermine the ontological security of their academic identity

    Application of a correlation correction factor in a microarray cross-platform reproducibility study

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    Background Recent research examining cross-platform correlation of gene expression intensities has yielded mixed results. In this study, we demonstrate use of a correction factor for estimating cross-platform correlations. Results In this paper, three technical replicate microarrays were hybridized to each of three platforms. The three platforms were then analyzed to assess both intra- and cross-platform reproducibility. We present various methods for examining intra-platform reproducibility. We also examine cross-platform reproducibility using Pearson\u27s correlation. Additionally, we previously developed a correction factor for Pearson\u27s correlation which is applicable when X and Y are measured with error. Herein we demonstrate that correcting for measurement error by estimating the disattenuated correlation substantially improves cross-platform correlations. Conclusion When estimating cross-platform correlation, it is essential to thoroughly evaluate intra-platform reproducibility as a first step. In addition, since measurement error is present in microarray gene expression data, methods to correct for attenuation are useful in decreasing the bias in cross-platform correlation estimates

    The misallocation of students to academic sets in maths: A study of secondary schools in England

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    Drawing upon data gathered from 9301 Year 7 students (12ā€“13 years old) from 46 secondary schools in England, this study represents the first largerā€scale attempt to compare their actual set allocations in maths with the counterfactual position where their allocation to sets is based solely on their prior attainment at the end of primary school [using their Key Stage 2 (KS2) fineā€grained scores in maths]. Through such an analysis, the study found that nearly a third of students (31.2%) had been misallocated to lower or higher sets than their KS2 results would have warranted. Beyond this, school setting practices were found to exacerbate differences in set allocation in relation to gender and ethnicity, but not socioeconomic background. The odds of girls being misallocated to lower sets in maths than their prior attainment would warrant was found to be 1.5 times higher than that for boys. Similarly, the odds of Black students being misallocated to lower sets was 2.4 times higher than for White students, whilst the odds of Asian students being misallocated to lower maths sets was 1.7 times higher than for White students. The article concludes by reflecting on the significant role that setting by attainment in secondary school can play in exacerbating already established patterns of educational inequalities in gender and ethnicity

    Expanding the parameters of academia

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    This paper draws on qualitative data gathered from two studies funded by the UK Leadership Foundation for Higher Education to examine the expansion of academic identities in higher education. It builds on Whitchurchā€™s earlier work, which focused primarily on professional staff, to suggest that the emergence of broadly based projects such as widening participation, learning support and community partnership is also impacting on academic identities. Thus, academic as well as professional staff are increasingly likely to work in multi-professional teams across a variety of constituencies, as well as with external partners, and the binary distinction between ā€˜academicā€™ and ā€˜non-academicā€™ roles and activities is no longer clear-cut. Moreover, there is evidence from the studies of an intentionality about deviations from mainstream academic career routes among respondents who could have gone either way. Consideration is therefore given to factors that influence individuals to work in more project-oriented areas, as well as to variables that affect ways in which these roles and identities develop. Finally, three models of academically oriented project activity are identified, and the implications of an expansion of academic identities are reviewed

    Why is it difficult for schools to establish equitable practices in allocating students to attainment 'sets'?

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    Research has consistently shown ā€˜abilityā€™ grouping (tracking) to be prey to poor practice, and to perpetuate inequity. A feature of these problems is inequitable and inaccurate practice in allocation to groups or ā€˜tracksā€™. Yet little research has examined whether such practices might be improved. Here, we examine survey and interview findings from a large-scale intervention study of grouping practices in 126 English secondary schools. We find that when schools are encouraged to allocate students and move them between groups according to equitable principles by participation in a ā€˜best practiceā€™ intervention, there is some increased equity of practice, i.e. a reduction in non-attainment factors used in allocation. However, the majority of schools continue to use subjective and potentially biased information to group students. Furthermore, some schools that claim to be using attainment setting appear to be using the inequitable practice of streaming. Our findings show that improvements in equity are constrained by operational and strategic factors, including timetabling, finance and teachersā€™ values and beliefs relating to student ability and progression. We suggest strategies for encouraging schools to change their grouping practices, drawing on approaches for working with complex organisations

    Structural Requirements for Dihydrobenzoxazepinone Anthelmintics: Actions against Medically Important and Model Parasites: Trichuris muris, Brugia malayi, Heligmosomoides polygyrus, and Schistosoma mansoni

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    Nine hundred million people are infected with the soil-transmitted helminths Ascaris lumbricoides (roundworm), hookworm, and Trichuris trichiura (whipworm). However, low single-dose cure rates of the benzimidazole drugs, the mainstay of preventative chemotherapy for whipworm, together with parasite drug resistance, mean that current approaches may not be able to eliminate morbidity from trichuriasis. We are seeking to develop new anthelmintic drugs specifically with activity against whipworm as a priority and previously identified a hit series of dihydrobenzoxazepinone (DHB) compounds that block motility of ex vivo Trichuris muris. Here, we report a systematic investigation of the structureā€“activity relationship of the anthelmintic activity of DHB compounds. We synthesized 47 analogues, which allowed us to define features of the molecules essential for anthelmintic action as well as broadening the chemotype by identification of dihydrobenzoquinolinones (DBQs) with anthelmintic activity. We investigated the activity of these compounds against other parasitic nematodes, identifying DHB compounds with activity against Brugia malayi and Heligmosomoides polygyrus. We also demonstrated activity of DHB compounds against the trematode Schistosoma mansoni, a parasite that causes schistosomiasis. These results demonstrate the potential of DHB and DBQ compounds for further development as broad-spectrum anthelmintics

    Learnersā€™ attitudes to mixed-attainment grouping: Examining the views of students of high, middle and low attainment

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    There is a substantial international literature around the impact of different types of grouping by attainment on the academic and personal outcomes of students. This literature, however, is sparse in student voices, especially in relation to mixed-attainment practices. Research has indicated that students of different attainment levels might have different experiences and views of grouping structures. This paper represents a significant contribution to this literature. Drawing on the data collected as part of a large study on student grouping and teaching in England, we analyse the attitudes of students of different attainment levels to mixed-attainment practice, focusing on their explanations for their preferences or aversion to mixed-attainment classes. The data-set is drawn from group discussions and individual interviews with 89 students age 11/12 (Year 7) from eight secondary schools practicing mixed-attainment grouping in mathematics and English. Our analysis identifies some broad patterns in student attitudes, including a strong preference for mixed attainment among those at lower prior attainment. The analysis of the explanations students give for their opinions on mixed-attainment practice demonstrates how the learner identities of different groups of students are constituted in various ways by the discourses around ā€˜abilityā€™, and constrained by the dominant ideology of ā€˜abilityā€™ hierarchy
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