3,034 research outputs found

    Researching creatively with pupils in Assessment for Learning (AfL) classrooms on experiences of participation and consultation

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    This paper reports on an ESRC TLRP project, Consulting Pupils on the Assessment of their Learning (CPAL). The CPAL project provides an additional theoretical perspective to the ‘educational benefits’ perspective of engaging pupil voice in learning and teaching (Rudduck et al., 2003) through its exploration of pupil rights specifically in relation to assessment issues presently on the policy agenda in the Northern Ireland context – notably Assessment for Learning (AfL). An emergent framework for assessing pupil rights, based on Article 12 of the United Nations Convention on the Rights of the Child (Lundy, 2007), is being used to explore the ways in which AfL classroom practice creates the conditions for increased pupil participation and consultation. Pupil views on their AfL classroom experiences and participation are explored by means of a variety of pupil-centred, creative research methods that engage and stimulate pupils to observe, communicate and analyse their learning and assessment experiences and give meaning to them. This presentation highlights preliminary data based on a sample of 11-14 years pupils' experiences of participation and consultation in classrooms adopting AfL pedagogical principles, and identifies characteristics that support or inhibit pupil participation in their learning and the expression of their views about such matters

    Evolution of Solid Processing Methods in Continuous Flow Technology: Reactive Extrusion

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    The frustrations of precipitation, fouling and blockages of liquid-based flow reactors are familiar to all researchers working with continuous flow equipment. There have been many innovative solutions to try and circumvent this issue. This short review will highlight the emerging technique of mechanochemistry and reactive extrusion as a continuous process that can directly work on solid (and liquid) materials and elicit chemical transformations

    CMB E/B decomposition of incomplete sky: a pixel space approach

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    CMB polarization signal may be decomposed into gradient-like (E) and curl-like (B) mode. We have investigated E/B decomposition in pixel space. We find E/B mixing due to incomplete sky is localized in pixel-space, and negligible in the regions far away from the masked area. By estimating the expected local leakage power, we have diagnosed ambiguous pixels. Our criteria for ambiguous pixels (i.e. r_c) is associated with the tensor-to-scalar ratio of B mode power spectrum, which the leakage power is comparable to. By setting r_c to a lower value, we may reduce leakage level, but reduce sky fraction at the same time. Therefore, we have solved \partial \Delta C_l/\partial r_c=0, and obtained the optimal r_c, which minimizes the estimation uncertainty, given a foreground mask and noise level. We have applied our method to a simulated map blocked by a foreground (diffuse + point source) mask. Our simulation shows leakage power is smaller than primordial (i.e. unlensed) B mode power spectrum of tensor-to-scalar ratio r\sim 10^{-3} at wide range of multipoles (50\lesssim l \lesssim 2000), while allowing us to retain sky fraction ~ 0.48.Comment: v2: the point of the method strengthened, v3: criteria for ambiguous pixels rigorously derived, v4: matched with the accepted version in A&A (minor change), v5: typos correcte

    A 6-12 GHz Analogue Lag-Correlator for Radio Interferometry

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    Aims: We describe a 6-12 GHz analogue correlator that has been developed for use in radio interferometers. Methods: We use a lag-correlator technique to synthesis eight complex spectral channels. Two schemes were considered for sampling the cross-correlation function, using either real or complex correlations, and we developed prototypes for both of them. We opted for the ``add and square'' detection scheme using Schottky diodes over the more commonly used active multipliers because the stability of the device is less critical. Results: We encountered an unexpected problem, in that there were errors in the lag spacings of up to ten percent of the unit spacing. To overcome this, we developed a calibration method using astronomical sources which corrects the effects of the non-uniform sampling as well as gain error and dispersion in the correlator.Comment: 14 pages, 21 figures, accepted for publication in A&

    A 6-12 GHz Analogue Lag-Correlator for Radio Interferometry

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    Aims: We describe a 6-12 GHz analogue correlator that has been developed for use in radio interferometers. Methods: We use a lag-correlator technique to synthesis eight complex spectral channels. Two schemes were considered for sampling the cross-correlation function, using either real or complex correlations, and we developed prototypes for both of them. We opted for the ``add and square'' detection scheme using Schottky diodes over the more commonly used active multipliers because the stability of the device is less critical. Results: We encountered an unexpected problem, in that there were errors in the lag spacings of up to ten percent of the unit spacing. To overcome this, we developed a calibration method using astronomical sources which corrects the effects of the non-uniform sampling as well as gain error and dispersion in the correlator.Comment: 14 pages, 21 figures, accepted for publication in A&

    Changes in the gut microbiota of mice orally exposed to methylimidazolium ionic liquids

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    Ionic liquids are salts used in a variety of industrial processes, and being relatively non-volatile, are proposed as environmentally-friendly replacements for existing volatile liquids. Methylimidazolium ionic liquids resist complete degradation in the environment, likely because the imidazolium moiety does not exist naturally in biological systems. However, there is limited data available regarding their mammalian effects in vivo. This study aimed to examine the effects of exposing mice separately to 2 different methylimidazolium ionic liquids (BMI and M8OI) through their addition to drinking water. Potential effects on key target organs-the liver and kidney-were examined, as well as the gut microbiome. Adult male mice were exposed to drinking water containing ionic liquids at a concentration of 440 mg/L for 18 weeks prior to examination of tissues, serum, urine and the gut microbiome. Histopathology was performed on tissues and clinical chemistry on serum for biomarkers of hepatic and renal injury. Bacterial DNA was isolated from the gut contents and subjected to targeted 16S rRNA sequencing. Mild hepatic and renal effects were limited to glycogen depletion and mild degenerative changes respectively. No hepatic or renal adverse effects were observed. In contrast, ionic liquid exposure altered gut microbial composition but not overall alpha diversity. Proportional abundance of Lachnospiraceae, Clostridia and Coriobacteriaceae spp. were significantly greater in ionic liquid-exposed mice, as were predicted KEGG functional pathways associated with xenobiotic and amino acid metabolism. Exposure to ionic liquids via drinking water therefore resulted in marked changes in the gut microbiome in mice prior to any overt pathological effects in target organs. Ionic liquids may be an emerging risk to health through their potential effects on the gut microbiome, which is implicated in the causes and/or severity of an array of chronic disease in humans

    A 160 Gbp fork fern genome shatters size record for eukaryotes

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    Vascular plants are exceptional among eukaryotes due to their outstanding genome size diversity which ranges ∌2,400-fold, including the largest genome so far recorded in the angiosperm Paris japonica (148.89 Gbp/1C). Despite available data showing that giant genomes are restricted across the Tree of Life, the biological limits to genome size expansion remain to be established. Here, we report the discovery of an even larger eukaryotic genome in Tmesipteris oblanceolata, a New Caledonian fork fern. At 160.45 Gbp/1C, this record-breaking genome challenges current understanding and opens new avenues to explore the evolutionary dynamics of genomic gigantism

    A Sunyaev-Zel'dovich Effect Survey for High Redshift Clusters

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    Interferometric observations of the Sunyaev-Zel'dovich Effect (SZE) toward clusters of galaxies provide sensitive cosmological probes. We present results from 1 cm observations (at BIMA and OVRO) of a large, intermediate redshift cluster sample. In addition, we describe a proposed, higher sensitivity array which will enable us to survey large portions of the sky. Simulated observations indicate that we will be able to survey one square degree of sky per month to sufficient depth that we will detect all galaxy clusters more massive than 2x10^{14} h^{-1}_{50}M_\odot, regardless of their redshift. We describe the cluster yield and resulting cosmological constraints from such a survey.Comment: 7 pages, 6 figures, latex, contribution to VLT Opening Symposiu

    Transverse energy distributions and J/ψJ/\psi production in Pb+Pb collisions

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    We have analyzed the latest NA50 data on transverse energy distributions and J/ψJ/\psi suppression in Pb+Pb collisions. The transverse energy distribution was analysed in the geometric model of AA collisions. In the geometric model, fluctuations in the number of NN collisions at fixed impact parameter are taken into account. Analysis suggests that in Pb+Pb collisions, individual NN collisions produces less , than in other AA collisions. The nucleons are more transparent in Pb+Pb collisions. The transverse energy dependence of the J/ψJ/\psi suppression was obtained following the model of Blaizot et al, where charmonium suppression is assumed to be 100% effective above a threshold density. With fluctuations in number of NN collisions taken into account, good fit to the data is obtained, with a single parameter, the threshold density.Comment: Revised version with better E_T fit. 4 pages, 2 figure
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