550 research outputs found

    The Blindness Revolution: Jernigan in His Own Words

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    Review of: The Blindness Revolution: Jernigan in His Own Words, by James H. Omvig

    Rocks and Hard Places: Exploring Educational Psychologists’ Perspectives on “Off-Rolling” or Illegal Exclusionary Practices in Mainstream Secondary Schools in England

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    Research being undertaken by the Universities of Exeter and Plymouth is exploring educational psychologists’ knowledge of, and perspectives on, exclusionary practices in schools in England, particularly illegal practices referred to as “off-rolling”. Preliminary findings from the survey element of a mixed methods research project are reported here. The role of business models in the provision of educational psychology services to schools is considered through the conceptual lens of Giroux, Agamben and Ball to highlight ambiguities around the client relationship and to recast individualised ethical dilemmas as systemic features that inhibit direct challenges to school practices relating to inclusion. It is suggested that traded and privatised services risk implicating educational psychologists in schools’ management of the (in)visibility of “off-rolling” and the manufactured legitimacy of varied exclusionary practices

    Barium sulfate crystallization dependence on upper rim calix[4]arene functional groups

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    Although the effects of p-sulfonated and p-phosphonated calix[4]arene on barium sulfate morphology are similar, their ability to form mesocrystals of material are markedly different. The p-phosphonated calix[4]arene results in the formation of fibre bundles similar to those previously observed during barium sulfate crystallization in the presence of di-block copolymers. The isostructural sulfonated calix[4]arene, however, affords material consistent with the initial formation of mesocrystals which subsequently fuse. This material shows significant beam damage when viewed under a transmission electron microscope (TEM) suggesting incorporation of the sulfonated calix[4]arene, although there was no evidence of this from X-ray diffraction and atomic force microscopy (AFM) studies. We hypothesise that this calixarene is incorporated without significant change in structure of the material, and that the interaction of the macrocycle with the barium sulfate lattice is sufficiently weak that surface AFM imaging is effective in removing it from the surface

    Intrinsic properties of the two replicative DNA polymerases of Pyrococcus abyssi in replicating abasic sites: possible role in DNA damage tolerance?

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    The definitive version is available at ww3.interscience.wiley.com. En libre-accès sur Archimer : http://archimer.ifremer.fr/doc/2008/publication-6113.pdfInternational audienceSpontaneous and induced abasic sites in hyperthermophiles DNA have long been suspected to occur at high frequency. Here, Pyrococcus abyssi was used as an attractive model to analyse the impact of such lesions onto the maintenance of genome integrity. We demonstrated that endogenous AP sites persist at a slightly higher level in P. abyssi genome compared with Escherichia coli. Then, the two replicative DNA polymerases, PabpolB and PabpolD, were characterized in presence of DNA containing abasic sites. Both Pabpols had abortive DNA synthesis upon encountering AP sites. Under running start conditions, PabpolB could incorporate in front of the damage and even replicate to the full-length oligonucleotides containing a specific AP site, but only when present at a molar excess. Conversely, bypassing activity of PabpolD was strictly inhibited. The tight regulation of nucleotide incorporation opposite the AP site was assigned to the efficiency of the proof-reading function, because exonuclease-deficient enzymes exhibited effective TLS. Steady-state kinetics reinforced that Pabpols are high-fidelity DNA polymerases onto undamaged DNA. Moreover, Pabpols preferentially inserted dAMP opposite an AP site, albeit inefficiently. While the template sequence of the oligonucleotides did not influence the nucleotide insertion, the DNA topology could impact on the progression of Pabpols. Our results are interpreted in terms of DNA damage tolerance

    Tropical montane cloud forest: Environmental drivers of vegetation structure and ecosystem function

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    Abstract:Tropical montane cloud forests (TMCF) are characterized by short trees, often twisted with multiple stems, with many stems per ground area, a large stem diameter to height ratio, and small, often thick leaves. These forests exhibit high root to shoot ratio, with a moderate leaf area index, low above-ground production, low leaf nutrient concentrations and often with luxuriant epiphytic growth. These traits of TMCF are caused by climatic conditions not geological substrate, and are particularly associated with frequent or persistent fog and low cloud. There are several reasons why fog might result in these features. Firstly, the fog and clouds reduce the amount of light received per unit area of ground and as closed-canopy forests absorb most of the light that reaches them the reduction in the total amount of light reduces growth. Secondly, the rate of photosynthesis per leaf area declines in comparison with that in the lowlands, which leads to less carbon fixation. Nitrogen supply limits growth in several of the few TMCFs where it has been investigated experimentally. High root : shoot biomass and production ratios are common in TMCF, and soils are often wet which may contribute to N limitation. Further study is needed to clarify the causes of several key features of TMCF ecosystems including high tree diameter : height ratio.This is the author accepted manuscript. The final version is available from Cambridge University Press via http://dx.doi.org/10.1017/S026646741500017

    The Experiences of Adult Education Instructors Adapting to the Online Teaching and Learning Environment

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    This case study tracks the narrative journey of four faculty women as they discovered ways to handle the transitional experience of moving from face-to-face classroom teaching into an online asynchronous adult learning environment. It is the intention of the study that, by documenting the experiences of these faculty, we will be able to provide recommendations that will assist and support other faculty beginning to teach in an online environment
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