2,186 research outputs found

    An electronic weather vane for field science

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    This paper details the construction of a weather vane for the measurement of wind direction in field situations. The purpose of its construction was to analyse how wind direction affected the attractiveness of an insect pheromone in a dynamic outdoor environment, where wind could be a significant contributor to odour movement. The apparatus described provides a cheap and easy-to-construct alternative to commercial wind vanes, and was shown to provide accurate and continuous measurement of wind direction

    Stability and error analysis of a splitting method using Robin–Robin coupling applied to a fluid–structure interaction problem

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    We analyze a splitting method for a canonical fluid structure interaction problem. The splittling method uses a Robin-Robin boundary condition, explicit strategy. We prove the method is stable and, furthermore, we provide an error estimate that shows the error at the final time T is O( √ T ∆t) where ∆t is the time step

    Results from the LSND Neutrino Oscillation Search

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    The Liquid Scintillator Neutrino Detector (LSND) at the Los Alamos Meson Physics Facility sets bounds on neutrino oscillations in the appearance channel nu_mu_bar --> nu_e_bar by searching for the signature of the reaction nu_e_bar p --> e^+ n: an e+^+ followed by a 2.2MeV gamma ray from neutron capture. Five e^{+/-} -- gamma coincidences are observed in time with the LAMPF beam, with an estimated background of 6.2 events. The 90\% confidence limits obtained are: Delta (m^2) < 0.07eV^2 for sin^2 (2theta) = 1, and sin^2(2theta) < 6 10^{-3} for Delta (m^2) > 20 eV^2.Comment: 10 pages, uses REVTeX and epsf macro

    Tracking building operational energy and carbon emissions using S-curve trajectories—a prototype tool

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    New and refurbished non-domestic buildings are failing to live up to their anticipated performance. Shortfalls show in excess energy consumption, high carbon dioxide emissions and other failings in quantitative and qualitative performance metrics. This paper describes the component parts of the performance gap using evidence from building performance evaluations. It introduces a way of visualising the consequences of decisions and actions that are known to compromise performance outcomes using a performance curve methodology (the S-curve) which plots performance, and the root causes of underperformance, from project inception to initial operation and beyond. The paper tests the hypothesis with two case studies. It also covers the initial development of a prototype visualisation tool designed to enable live projects to track emerging operational energy and emissions against a high energy and emissions trajectory created from empirical evidence. The tool aims to help practitioners identify key risk factors that could compromise building performance and mitigate these risks at different stages of procurement. Practical application: The Operational Energy and Carbon (OpEC) visualisation tool is designed for wide industrial application, on all sizes of a non-domestic building project, large and small. It aims to visualise the likely outturn energy performance of a project by calculating the penalties for shortcomings in project delivery. The penalties are visualised as weighted trajectories of energy and carbon dioxide emissions. The prototype tool aims to fill a gap between the capabilities of powerful energy modelling tools used in design and the capacity of non-specialist stakeholders to understand the emerging energy characteristics of a project as it moves through procurement, design, construction, and delivery

    Numerical Computations with H(div)-Finite Elements for the Brinkman Problem

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    The H(div)-conforming approach for the Brinkman equation is studied numerically, verifying the theoretical a priori and a posteriori analysis in previous work of the authors. Furthermore, the results are extended to cover a non-constant permeability. A hybridization technique for the problem is presented, complete with a convergence analysis and numerical verification. Finally, the numerical convergence studies are complemented with numerical examples of applications to domain decomposition and adaptive mesh refinement.Comment: Minor clarifications, added references. Reordering of some figures. To appear in Computational Geosciences, final article available at http://www.springerlink.co

    Further observations on mechanisms of bone destruction by squamous carcinomas of the head and neck: the role of host stroma.

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    Mechanisms of bone invasion by squamous carcinomas of the head and neck have been investigated using fresh tumours and established tumour cell lines in an in vitro bone resorption assay with 45Ca-labelled mouse calvaria. Fresh tumours regularly resorb bone in vitro. Activity is consistently reduced by indomethacin. The tumours release E2 prostaglandins (PGE2) in amounts sufficient to account for approximately 50% of the bone resorption observed. Small amounts of non-prostaglandin (indomethacin-resistant) osteolytic factors are also produced. Control non-neoplastic tissues show a variable capacity to resorb bone in vitro; PGE2 levels in these tissues may be related to their content of inflammatory cells. Tumour cell lines also resorb bone in vitro but, for most lines, activity is not significantly blocked by indomethacin and PGE2 levels are generally insufficient to account for the osteolysis observed. Non-prostaglandin bone resorbing factors thus predominate. It is concluded that most squamous cancers of the head and neck are osteolytic in vitro and release a mixture of prostaglandin and non-prostaglandin factors which stimulate osteoclastic bone resorption. These factors are derived from both neoplastic and stromal elements, and are "tumour-associated" rather than "tumour-specific". In vitro bone resorption and prostaglandin release does not correlate with pathological features of the tumour or with post-operative survival

    Children’s experiences of domestic violence and abuse: siblings’ accounts of relational coping

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    This article explores how young people see their relationships, particularly their sibling relationships, in families affected by domestic violence, and how relationality emerges in their accounts as a resource to build an agentic sense of self. The ‘voice’ of children is largely absent from domestic violence literature, which typically portrays them as passive, damaged and relationally incompetent. Children’s own understandings of their relational worlds are often overlooked, and consequently existing models of children’s social interactions give inadequate accounts of their meaning-making-in-context. Drawn from a larger study of children’s experiences of domestic violence and abuse, this paper uses two case studies of sibling relationships to explore young people’s use of relational resources, for coping with violence in the home. The paper explores how relationality and coping intertwine in young people’s accounts, and disrupts the taken for granted assumption that children’s ‘premature caring’ or ‘parentification’ is (only) pathological in children’s responses to domestic violence. This has implications for understanding young people’s experiences in the present, and supporting their capacity for relationship building in the future

    Openspritzer: an open hardware pressure ejection system for reliably delivering picolitre volumes

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    The ability to reliably and precisely deliver picolitre volumes is an important component of biological research. Here we describe a high-performance, low-cost, open hardware pressure ejection system (Openspritzer), which can be constructed from off the shelf components. The device is capable of delivering minute doses of reagents to a wide range of biological and chemical systems. In this work, we characterise the performance of the device and compare it to a popular commercial system using twophoton fluorescence microscopy. We found that Openspritzer provides the same level of control over delivered reagent dose as the commercial system. Next, we demonstrate the utility of Openspritzer in a series of standard neurobiological applications. First, we used Openspritzer to deliver precise amounts of reagents to hippocampal neurons to elicit time- and dose-precise responses on neuronal voltage. Second, we used Openspritzer to deliver infectious viral and bacterial agents to living tissue. This included viral transfection of hippocampal interneurons with channelrhodopsin for the optogenetic manipulation of hippocampal circuitry with light. We anticipate that due to its high performance and low cost Openspritzer will be of interest to a broad range of researchers working in the life and physical sciences
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