32,312 research outputs found

    Advances in induction-heated plasma torch technology

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    Continuing research has resulted in significant advances in induction-heated plasma torch technology which extend and enhance its potential for broad range of uses in chemical processing, materials development and testing, and development of large illumination sources. Summaries of these advances are briefly described

    Employment, wage structure, and the economic cycle: differences between immigrants and natives in Germany and the UK

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    Differences in the cyclical pattern of employment and wages of immigrants relative to natives have largely gone unnoticed in the migration literature. In this paper we show that immigrants and natives react differently to the economic cycle. Based on over two decades of micro data, our investigation is for two of the largest immigrant receiving countries in Europe which at the same time are characterised by different immigrant populations as well as different economic cycles, Germany and the UK. Understanding the magnitude, nature and possible causes of differences in responses is relevant for assessing the economic performance of immigrant communities over time. We show that there are substantial differences in cyclical responses between immigrants and natives. Our analysis illustrates the magnitude of these differences, while distinguishing between different groups of immigrants. Differences in responses may be due to differences in the skill distribution between immigrant groups and natives, or differences in demand for immigrants and natives of the same skills due to differential allocation of immigrants and natives across industries and regions. We demonstrate that substantial differences in cyclical patterns remain, even within narrowly defined groups. Finally, we estimate a more structural factor type model that, using regional variation in economic conditions, separates responses to economic shocks from a secular trend and allows us to obtain a summary measure for these differences within education groups

    Tool pre-tensions covers prior to lacing

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    In securing a bulky object in a storage compartment, a cinching or tightening tool is used to draw two opposing cover halves together at a predetermined tension to permit quick lacing to retain the stored object. This tool is also useful in fabrication industries to draw components together during assembly or treating

    Tacit knowledge and the biological weapons regime

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    Bioterrorism has become increasingly salient in security discourse in part because of perceived changes in the capacity and geography of life science research. Yet its salience is founded upon a framing of changes in science and security that does not always take into consideration the somewhat slippery concept of ‘tacit knowledge’, something poorly understood, disparately conceptualised and often marginalised in discussions on state and non-state biological weapons programmes. This paper looks at how changes in science and technology—particularly the evolution of information and communications technology—has contributed to the partial erosion of aspects of tacit knowledge and the implications for the biological weapons regime. This paper concludes by arguing that the marginalisation of tacit knowledge weakens our understanding of the difficulties encountered in biological weapons programmes and can result in distorted perceptions of the threat posed by dual-use biotechnology in the 21st century

    Transthoracic three-dimensional echocardiography for the assessment of straddling tricuspid or mitral valves

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    Background The advent of 3D echocardiography has provided a technique which, potentially, could afford significant additional information over conventional cross-sectional echocardiography in the assessment of patients with straddling atrioventricular valves prior to surgical correction. Methods Eight patients, aged from 1 month to 9˙2 years, were examined with 3D echocardiography. All but three had discordant ventriculoarterial connections or double outlet right ventricle. Data suitable for reconstruction was acquired with transthoracic scanning. Right and left ventricular volumes were calculated in the 3D dataset. Results 3D echocardiography proved capable of defining the exact degree of straddling by imaging theproportion of tension apparatus attached to either side of the ventricular septum. It was able also to display the atrioventricular junction “en face”, thus permitting identification of the precise site of insertion of the muscular ventricular septum relative to the atrioventricular junction. This made it possiblefirst, to calculate the degree of valvar override, and second, to predict the location of the penetrating atrioventricular bundle. End-diastolic volume of the right ventricle in those with straddling tricuspid valves was 73 (61–83)% of normal, and, of the left ventricle in those with mitral valvar straddling 71 (40‐97)% of normal. Conclusions 3D echocardiography can aid in planning the optimal surgical procedure in patients with straddling or overrriding atrioventricular valves, as it provides diagnostic information superiorto standard crosssectional techniques. It also allows for exact measurement of the volumes of the respective ventricles

    High electrical resistivity carbon/graphite fibers

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    Carbon/graphite fibers were chemically oxidized in the liquid phase to fibers of graphite oxide. Resistivity increases as high as 10,000 times were obtained, the oxidized fiber decomposed on exposure to atmosphere. A factor of 1,000 remained as a stable increment. The largest change observed was 1,000,000 times. Best results were obtained on the most highly graphitized fibers. Electrochemical oxidation yielded a lower increase--about 10 times, but provided a controllable method of synthesis and insight to the mechanism of reaction. Tensile tests indicated that the strength of the fiber on oxidation was decreased by no more than 25 percent
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