526 research outputs found

    Hydrodynamic Coupling of Two Brownian Spheres to a Planar Surface

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    We describe direct imaging measurements of the collective and relative diffusion of two colloidal spheres near a flat plate. The bounding surface modifies the spheres' dynamics, even at separations of tens of radii. This behavior is captured by a stokeslet analysis of fluid flow driven by the spheres' and wall's no-slip boundary conditions. In particular, this analysis reveals surprising asymmetry in the normal modes for pair diffusion near a flat surface.Comment: 4 pages, 4 figure

    Ungrading General Education: Preliminary Results from a Pilot Study

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    A group of faculty members representing more than 20 courses listed in the Eastern Kentucky University General Education curriculum participated in a pilot program to test and measure the effectiveness of “ungraded” pedagogy. “Ungrading,” as defined by the group, can be any conscious effort to move student emphasis away from grades and onto learning. Given this definition, ungrading took many forms in the pilot: gradeless classrooms, grading contracts, and greater choice of assignments by students, to name a few. At the end of the semester, quantitative and qualitative data was gathered from student course evaluations; DFW and retention rates were considered; and focus groups comprised of students in ungraded classes were convened. This piece provides preliminary results from the pilot and in an effort to begin a larger conversation about the widespread adoption of ungraded pedagogies

    Negotiating queer and religious identities in higher education: queering ‘progression’ in the ‘university experience’

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    This article addresses the negotiation of ‘queer religious’ student identities in UK higher education. The ‘university experience’ has generally been characterised as a period of intense transformation and self-exploration, with complex and overlapping personal and social influences significantly shaping educational spaces, subjects and subjectivities. Engaging with ideas about progressive tolerance and becoming, often contrasted against ‘backwards’ religious homophobia as a sentiment/space/subject ‘outside’ education, this article follows the experiences and expectations of queer Christian students. In asking whether notions of ‘queering higher education’ (Rumens 2014 Rumens, N. 2014. “Queer Business: Towards Queering the Purpose of the Business School.” In The Entrepreneurial University: Public Engagements, Intersecting Impacts, edited by Y. Taylor, 82–104. Basingstoke: Palgrave Macmillan.) ‘fit’ with queer-identifying religious youth, the article explores how educational experiences are narrated and made sense of as ‘progressive’. Educational transitions allow (some) sexual-religious subjects to negotiate identities more freely, albeit with ongoing constraints. Yet perceptions of what, where and who is deemed ‘progressive’ and ‘backwards’ with regard to sexuality and religion need to be met with caution, where the ‘university experience’ can shape and shake sexual-religious identity

    Tightness of slip-linked polymer chains

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    We study the interplay between entropy and topological constraints for a polymer chain in which sliding rings (slip-links) enforce pair contacts between monomers. These slip-links divide a closed ring polymer into a number of sub-loops which can exchange length between each other. In the ideal chain limit, we find the joint probability density function for the sizes of segments within such a slip-linked polymer chain (paraknot). A particular segment is tight (small in size) or loose (of the order of the overall size of the paraknot) depending on both the number of slip-links it incorporates and its competition with other segments. When self-avoiding interactions are included, scaling arguments can be used to predict the statistics of segment sizes for certain paraknot configurations.Comment: 10 pages, 6 figures, REVTeX

    Jasmonic Acid-Induced Changes in Brassica oleracea Affect Oviposition Preference of Two Specialist Herbivores

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    Jasmonic acid (JA) is a key hormone involved in plant defense responses. The effect of JA treatment of cabbage plants on their acceptability for oviposition by two species of cabbage white butterflies, Pieris rapae and P. brassicae, was investigated. Both butterfly species laid fewer eggs on leaves of JA-treated plants compared to control plants. We show that this is due to processes in the plant after JA treatment rather than an effect of JA itself. The oviposition preference for control plants is adaptive, as development time from larval hatch until pupation of P. rapae caterpillars was longer on JA-treated plants. Total glucosinolate content in leaf surface extracts was similar for control and treated plants; however, two of the five glucosinolates were present in lower amounts in leaf surface extracts of JA-treated plants. When the butterflies were offered a choice between the purified glucosinolate fraction isolated from leaf surface extracts of JA-treated plants and that from control plants, they did not discriminate. Changes in leaf surface glucosinolate profile, therefore, do not seem to explain the change in oviposition preference of the butterflies after JA treatment, suggesting that as yet unknown infochemicals are involved

    Discovery pipelines for marine resources : an ocean of opportunity for biotechnology?

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    This project has received funding from the European Union’s Horizon 2020 research and innovation programme under Grant agreement No 645884. CABI is an international intergovernmental organisation, and we gratefully acknowledge the core financial support from our member countries (and lead agencies) including the United Kingdom (Department for International Development), China (Chinese Ministry of Agriculture), Australia (Australian Centre for International Agricultural Research), Canada (Agriculture and Agri-Food Canada), Netherlands (Directorate-General for International Cooperation),and Switzerland (Swiss Agency for Development and Cooperation). See https://www.cabi.org/about-cabi/who-we-work-with/key-donors/ for full details.Marine microbial diversity offers enormous potential for discovery of compounds of crucial importance in healthcare, food security and bioindustry. However, access to it has been hampered by the difficulty of accessing and growing the organisms for study. The discovery and exploitation of marine bioproducts for research and commercial development requires state-of-the-art technologies and innovative approaches. Technologies and approaches are advancing rapidly and keeping pace is expensive and time consuming. There is a pressing need for clear guidance that will allow researchers to operate in a way that enables the optimal return on their efforts whilst being fully compliant with the current regulatory framework. One major initiative launched to achieve this, has been the advent of European Research Infrastructures. Research Infrastructures (RI) and associated centres of excellence currently build harmonized multidisciplinary workflows that support academic and private sector users. The European Marine Biological Research Infrastructure Cluster (EMBRIC) has brought together six such RIs in a European project to promote the blue bio-economy. The overarching objective is to develop coherent chains of high-quality services for access to biological, analytical and data resources providing improvements in the throughput and efficiency of workflows for discovery of novel marine products. In order to test the efficiency of this prototype pipeline for discovery, 248 rarely-grown organisms were isolated and analysed, some extracts demonstrated interesting biochemical properties and are currently undergoing further analysis. EMBRIC has established an overarching and operational structure to facilitate the integration of the multidisciplinary value chains of services to access such resources whilst enabling critical mass to focus on problem resolution.Publisher PDFPeer reviewe

    Towards mentoring as feminist praxis in early childhood education and care in England

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    Following our contribution to a study of mentoring in seven European countries, we explored epistemological and ontological inconsistencies within mainstream mentoring systems and their regulated practice in England. We considered how feminist mentoring praxis can unsettle conceptualisations of mentoring relationships and challenge inequity in the early education systems and the practice of teaching young children. Predominantly female, early childhood educators suffer from low status in England, and their working lives may be controlled and policed through inequitable systems. On entering the workforce, trainees encounter a reductionist policy milieu where mentoring structures and normative assessment arrangements contribute to inequity. Mentors play pivotal roles in inducting trainees into their worlds of work with young children. Mentoring relationships can determine whether trainees accept the status quo. Principles derived from feminist praxis enable mentors to practise an ‘engaged pedagogy’, co-constructing knowledge, subverting hierarchies and contesting taken-for-granted aspects of policy and practice
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