5,880 research outputs found

    Space Shuttle: MDAC/MMC space shuttle booster determination of stability and control characteristics and power effects at subsonic speed, Mach numbers zero and 0.26

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    Low speed wind tunnel tests of stability and control characteristics of space shuttle booster at subsonic speed

    Investigating people: a qualitative analysis of the search behaviours of open-source intelligence analysts

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    The Internet and the World Wide Web have become integral parts of the lives of many modern individuals, enabling almost instantaneous communication, sharing and broadcasting of thoughts, feelings and opinions. Much of this information is publicly facing, and as such, it can be utilised in a multitude of online investigations, ranging from employee vetting and credit checking to counter-terrorism and fraud prevention/detection. However, the search needs and behaviours of these investigators are not well documented in the literature. In order to address this gap, an in-depth qualitative study was carried out in cooperation with a leading investigation company. The research contribution is an initial identification of Open-Source Intelligence investigator search behaviours, the procedures and practices that they undertake, along with an overview of the difficulties and challenges that they encounter as part of their domain. This lays the foundation for future research in to the varied domain of Open-Source Intelligence gathering

    Secondary school admissions

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    Adaptive significance of functional germination traits in crop wild relatives of Brassica

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    Functional germination traits contribute to both niche competitiveness and crop yield outcomes. However, there is little understanding of the adaptive significance of the germination thermal- and hydro-parameters in crop wild relatives (CWRs), yet these species are anticipated to be the source of adaptive traits for future agriculture. Seeds of 10 seed lots of Brassica species, sub-species and inbred lines from across Europe, North Africa and the Middle East were subjected to a range of temperature and water potential conditions. The germination progress curves recorded were analysed using repeated probit analysis and the functional trait parameters (thermal- and hydro thresholds and times) determined. Relationships between these seed parameters (and the physical trait, seed mass) and the seed source environment were investigated

    Quantitative Analysis of Heavy Metals in Children’s Toys and Jewelry: A Multi-Instrument, Multi-Technique Exercise in Analytical Chemistry and Public Health

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    For most chemistry curricula, laboratory-based activities in quantitative and instrumental analysis continue to be an important aspect of student development/training, one that can be more effective if conceptual understanding is delivered through an inquiry-based process relating the material to relevant issues of public interest and student career trajectories. Laboratory experiences that actively engage students in this manner can be difficult to identify and execute. A special topics, project-based laboratory module is presented here that utilizes multiple techniques and instruments to investigate toxic metal content (lead, cadmium, and arsenic) in children’s toys and toy jewelry. The module effectively illustrates a considerable number of fundamental and advanced quantitative analysis principles including sample digestion, Beer–Lambert law, calibration curve, and standard addition analyses, as well as instrumental analysis considerations of atomic absorption spectroscopy including atomization efficiency (e.g., flames vs furnaces), matrix modifiers, and nondestructive spectroscopy. Module effectiveness stems from the illustration of critical chemical analysis principles in the context of projects with student-directed hypotheses and experimental results that are clearly relevant to the interface of basic science, medicine, and public health: primary career interests for a significant number of undergraduates in the physical and life sciences

    From spin to anyon notation: The XXZ Heisenberg model as a D3D_{3} (or su(2)4su(2)_{4}) anyon chain

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    We discuss a relationship between certain one-dimensional quantum spin chains and anyon chains. In particular we show how the XXZ Heisenberg chain is realised as a D3D_{3} (alternately su(2)4su(2)_{4}) anyon model. We find the difference between the models lie primarily in choice of boundary condition.Comment: 13 page
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