100 research outputs found

    Radical “Citizens of the World,” 1790–95: The Early Career of Henry Redhead Yorke

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    This article takes a new look at British radicalism in the 1790s and explores it within broad geographical and cultural frameworks and through the early career of Henry Redhead Yorke, a West Indian Creole who became a radical in England but frequently recanted his politics. It views radicalism within the Atlantic World and provides a broader interpretation of the excluded majority than as an English working class. It examines the radical “citizens of the world” and sheds new light on the apparent conflict within English radicalism between universalist and constitutionalist ideologies. Politicization and identity are the key themes here examined within micro- and macro-histories

    In vivo laboratory practicals in research-led teaching: An example using glucose tolerance tests in lean and obese mice

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    The use of animal models is an essential part of medical research and drug development. The essential skills required to be able to do such research includes experimental design, statistical analysis and the actual handling and treating of the animals (in vivo skills). The number of students in the U.K. receiving training in handling and experimenting on animals has declined rapidly in the last few decades which has led to initiatives to increase numbers of students with these skills to meet demand. Within the Department of Pharmacology and Therapeutics at King's College London, we run a course for 2nd year undergraduates entitled “Animal models of disease and injury”. This course not only covers the theoretical and ethical aspects of using animals in research, but also contains practical laboratory classes in which students get hands-on experience using animals. One of the laboratory classes we run is a glucose tolerance test in obese and lean mice. This is an example of research-led teaching which aims to develop research skills through engaging students in research like activities. In this paper, we outline the methodology of the glucose tolerance practical and highlight some of the skills we and the students think they gain by research-led teaching such as this

    Simulations of extensional flow in microrheometric devices

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    We present a detailed numerical study of the flow of a Newtonian fluid through microrheometric devices featuring a sudden contraction–expansion. This flow configuration is typically used to generate extensional deformations and high strain rates. The excess pressure drop resulting from the converging and diverging flow is an important dynamic measure to quantify if the device is intended to be used as a microfluidic extensional rheometer. To explore this idea, we examine the effect of the contraction length, aspect ratio and Reynolds number on the flow kinematics and resulting pressure field. Analysis of the computed velocity and pressure fields show that, for typical experimental conditions used in microfluidic devices, the steady flow is highly three-dimensional with open spiraling vortical structures in the stagnant corner regions. The numerical simulations of the local kinematics and global pressure drop are in good agreement with experimental results. The device aspect ratio is shown to have a strong impact on the flow and consequently on the excess pressure drop, which is quantified in terms of the dimensionless Couette and Bagley correction factors. We suggest an approach for calculating the Bagley correction which may be especially appropriate for planar microchannels

    Child's Play? Children and Young People's Resistances to Domestic Violence and Abuse

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    Children and young people's (CYP) space to play can be constrained in families affected by domestic violence and abuse (DVA), potentially impacting their development. Play also has the potential to strengthen CYP's capacity to resist controlling and abusive dynamics in the family. Interviews were conducted with 107 CYP aged 8–18, and were analysed using interpretive interactionism. Three themes relevant to children's experiences of play were identified: Play and Coercive Control; Play Re‐makes the World and Play and Relationality. This article highlights the potential for play to enable children to retain a sense of relational connectedness and agency, despite violence and control; we argue for more opportunities for children to play away from the gaze of adults and advocate for more dedicated services for families who experience DVA

    Thermalized Displaced and Squeezed Number States in Coordinate Representation

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    Within the framework of thermofield dynamics, the wavefunctions of the thermalized displaced number and squeezed number states are given in the coordinate representation. Furthermore, the time evolution of these wavefunctions is considered by introducing a thermal coordinate representation, and we also calculate the corresponding probability densities, average values and variances of position coordinate, which are consistent with results in the literature.Comment: 12 pages, no figures, Revtex. v3: substantially revise

    The Inertio-Elastic Planar Entry Flow of Low-Viscosity Elastic Fluids in Micro-fabricated Geometries

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    The non-Newtonian flow of dilute aqueous polyethylene oxide (PEO) solutions through microfabricated planar abrupt contraction-expansions is investigated. The contraction geometries are fabricated from a high-resolution chrome mask and cross-linked PDMS gels using the tools of soft-lithography. The small length scales and high deformation rates in the contraction throat lead to significant extensional flow effects even with dilute polymer solutions having time constants on the order of milliseconds. The dimensionless extra pressure drop across the contraction increases by more than 200% and is accompanied by significant upstream vortex growth. Streak photography and videomicroscopy using epifluorescent particles shows that the flow ultimately becomes unstable and three-dimensional. The moderate Reynolds numbers (0.03 ⤠Re ⤠44) associated with these high Deborah number (0 ⤠De ⤠600) microfluidic flows results in the exploration of new regions of the Re-De parameter space in which the effects of both elasticity and inertia can be observed. Understanding such interactions will be increasingly important in microfluidic applications involving complex fluids and can best be interpreted in terms of the elasticity number, El = De/Re, which is independent of the flow kinematics and depends only on the fluid rheology and the characteristic size of the device.NS

    Long-lived magnetism from solidification-driven convection on the pallasite parent body.

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    Palaeomagnetic measurements of meteorites suggest that, shortly after the birth of the Solar System, the molten metallic cores of many small planetary bodies convected vigorously and were capable of generating magnetic fields. Convection on these bodies is currently thought to have been thermally driven, implying that magnetic activity would have been short-lived. Here we report a time-series palaeomagnetic record derived from nanomagnetic imaging of the Imilac and Esquel pallasite meteorites, a group of meteorites consisting of centimetre-sized metallic and silicate phases. We find a history of long-lived magnetic activity on the pallasite parent body, capturing the decay and eventual shutdown of the magnetic field as core solidification completed. We demonstrate that magnetic activity driven by progressive solidification of an inner core is consistent with our measured magnetic field characteristics and cooling rates. Solidification-driven convection was probably common among small body cores, and, in contrast to thermally driven convection, will have led to a relatively late (hundreds of millions of years after accretion), long-lasting, intense and widespread epoch of magnetic activity among these bodies in the early Solar System.The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013) / ERC Grant Agreement No. 320750, the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 312284, the Natural Environment Research Council, Fundación ARAID and the Spanish MINECO MAT2011-23791.This is the accepted manuscript. The final version is available from Nature at http://www.nature.com/nature/journal/v517/n7535/full/nature14114.html
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