6,903 research outputs found

    A Wider Role For Technicians in Science Practical Work With School Students?

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    This paper reports the results of a study made on the impact of improved deployment of science technicians in the classroom could directly benefit students in practical science investigations. Science technicians are skilled individuals whose understanding of practical work is a valuable resource not being used of in support of students understanding of science. Aspects of practical work and technician support were scrutinised, through information attained from a post-16 student survey to improve understanding about this teaching tool, to establish if it was being used to its full potential within science lessons. Analysis was also made of students’ perceptions of school science. The main outcomes were that the majority of students enjoyed science practical work and felt that science could not be taught without it. Students studying science at pre-university level attained a greater understanding, through participating in relevant practical work, than students who had studied it at earlier, compulsory levels. Students reported that science technicians provide impact on student learning when contact time was the greatest

    The Role of School Technicians In Promoting Science Through Practical Work

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    This is a review of the role of practical work in UK’s secondary school science lessons, the impact that practical work has in the promotion of science, the challenges created through use of non-specialist science teachers and a possible additional role for science technicians. The paper considers how improved deployment of suitably experienced school science technicians and their recognition, by schools’ management, for their involvement in the delivery of training in the use of practical work, for less experienced teachers, could benefit schools and their students. This together with its companion paper endeavours to show how the more effective use of practical work and technicians can encourage more students to select science at higher, non-compulsory levels

    Characterising the tumour morphological response to therapeutic intervention:an ex vivo model

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    In cancer, morphological assessment of histological tissue samples is a fundamental part of both diagnosis and prognosis. Image analysis offers opportunities to support that assessment through quantitative metrics of morphology. Generally, morphometric analysis is carried out on two dimensional tissue section data and so only represents a small fraction of any tumour. We present a novel application of three-dimensional (3D) morphometrics for 3D imaging data obtained from tumours grown in a culture model. Minkowski functionals, a set of measures that characterise geometry and topology in n-dimensional space, are used to quantify tumour topology in the absence of and in response to therapeutic intervention. These measures are used to stratify the morphological response of tumours to therapeutic intervention. Breast tumours are characterised by estrogen receptor (ER) status, human epidermal growth factor receptor (HER)2 status and tumour grade. Previously, we have shown that ER status is associated with tumour volume in response to tamoxifen treatment ex vivo. Here, HER2 status is found to predict the changes in morphology other than volume as a result of tamoxifen treatment ex vivo. Finally, we show the extent to which Minkowski functionals might be used to predict tumour grade.Minkowski functionals are generalisable to any 3D data set, including in vivo and cellular systems. This quantitative topological analysis can provide a valuable link among biomarkers, drug intervention and tumour morphology that is complementary to existing, non-morphological measures of tumour response to intervention and could ultimately inform patient treatment

    The fitness of pseudomonas aeruginosa quorum sensing signal cheats is influenced by the diffusivity of the environment

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    Experiments examining the social dynamics of bacterial quorum sensing (QS) have focused on mutants which do not respond to signals and the role of QS-regulated exoproducts as public goods. The potential for QS signal molecules to themselves be social public goods has received much less attention. Here, we analyze how signal-deficient (lasI) mutants of the opportunistic pathogen Pseudomonas aeruginosa interact with wild-type cells in an environment where QS is required for growth. We show that when growth requires a “private” intracellular metabolic mechanism activated by the presence of QS signal, lasI mutants act as social cheats and outcompete signal-producing wild-type bacteria in mixed cultures, because they can exploit the signals produced by wild-type cells. However, reducing the ability of signal molecules to diffuse through the growth medium results in signal molecules becoming less accessible to mutants, leading to reduced cheating. Our results indicate that QS signal molecules can be considered social public goods in a way that has been previously described for other exoproducts but that spatial structuring of populations reduces exploitation by noncooperative signal cheats

    The X-ray reflection spectrum of the radio-loud quasar 4C 74.26

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    The relativistic jets created by some active galactic nuclei are important agents of AGN feedback. In spite of this, our understanding of what produces these jets is still incomplete. X-ray observations, which can probe the processes operating in the central regions in immediate vicinity of the supermassive black hole, the presumed jet launching point, are potentially particularly valuable in illuminating the jet formation process. Here, we present the hard X-ray NuSTAR observations of the radio-loud quasar 4C 74.26 in a joint analysis with quasi-simultaneous, soft X-ray Swift observations. Our spectral analysis reveals a high-energy cut-off of 18335+51_{-35}^{+51} keV and confirms the presence of ionized reflection in the source. From the average spectrum we detect that the accretion disk is mildly recessed with an inner radius of Rin=4180RgR_\mathrm{in}=4-180\,R_\mathrm{g}. However, no significant evolution of the inner radius is seen during the three months covered by our NuSTAR campaign. This lack of variation could mean that the jet formation in this radio-loud quasar differs from what is observed in broad-line radio galaxies.Comment: Accepted for publication in Ap

    piRNAs and Aubergine cooperate with Wispy poly(A) polymerase to stabilize mRNAs in the germ plasm

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    Piwi-interacting RNAs (piRNAs) and PIWI proteins play a crucial role in germ cells by repressing transposable elements and regulating gene expression. In Drosophila, maternal piRNAs are loaded into the embryo mostly bound to the PIWI protein Aubergine (Aub). Aub targets maternal mRNAs through incomplete base-pairing with piRNAs and can induce their destabilization in the somatic part of the embryo. Paradoxically, these Aub-dependent unstable mRNAs encode germ cell determinants that are selectively stabilized in the germ plasm. Here we show that piRNAs and Aub actively protect germ cell mRNAs in the germ plasm. Aub directly interacts with the germline-specific poly(A) polymerase Wispy, thus leading to mRNA polyadenylation and stabilization in the germ plasm. These results reveal a role for piRNAs in mRNA stabilization and identify Aub as an interactor of Wispy for mRNA polyadenylation. They further highlight the role of Aub and piRNAs in embryonic patterning through two opposite functions
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