9,261 research outputs found

    \u3ci\u3eWilliamsonia Lintneri\u3c/i\u3e (Odonata: Corduliidae) - A First Michigan Record With Additional Notes on \u3ci\u3eW. Fletcheri\u3c/i\u3e

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    Williamsonia lintneri is newly recorded for Michigan, and additional Michigan sites are given for W. fletcheri. Both species appear to be bog/fen- obligate inhabitants, and adults may appear as early as late April in Michi- gan. In addition, the North American distributions of both species are sum- marized

    Linear transmitter design for MSAT terminals

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    One of the factors that will undoubtedly influence the choice of modulation format for mobile satellites, is the availability of cheap, power-efficient, linear amplifiers for mobile terminal equipment operating in the 1.5-1.7 GHz band. Transmitter linearity is not easily achieved at these frequencies, although high power (20W) class A/AB devices are becoming available. However, these components are expensive and require careful design to achieve a modest degree of linearity. In this paper an alternative approach to radio frequency (RF) power amplifier design for mobile satellite (MSAT) terminals using readily-available, power-efficient, and cheap class C devices in a feedback amplifier architecture is presented

    The growth dynamics of technology-based firms in Scotland

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    In recent years high growth firms (HGFs) undertaking rapid, transformative growth, have been identified as important contributors to economic growth (Acs et al, 2008; Anyadike-Danes et al, 2009; OECD, 2010). For a wide variety of reasons, notably their contribution to employment growth, high export intensity, strong contribution to productivity growth and innovation, HGFs have been hailed as vital drivers of economic competitiveness (Henrekson and Johansson, 2010). As a consequence, these firms (often referred to as 'gazelles'), have been accorded a central role in many economic development strategies at both national and regional levels, especially during a time of economic austerity where employment growth has been an overriding policy goal for many governments (BERR, 2008; NESTA, 2011; OECD, 2010; Scottish Enterprise, 2011). Yet despite the strong policy focus on the promotion of HGFs in recent times, much remains unknown about these organisations and how best to support them (Henrekson and Johansson, 2010; Anyadike-Danes et al, 2012; Mason and Brown, forthcoming). Scottish Enterprise recently commissioned research on Scotland’s population of HGFs (Mason and Brown, 2010). This was the first comprehensive analysis of these firms ever conducted in Scotland and some of the findings were published in this journal (Brown and Mason, 2010). One of the most significant conclusions from this study was that they are extremely heterogeneous in terms of their age, size, ownership and industry sector. Few fit the stereotypical ‘gazelle’ definition which refers to young high growth firms that are less than five years old. The vast majority are over 10 years old, with some significantly older (Mason and Brown, 2010). Furthermore, only a relatively small proportion of these firms are in high-tech areas of the economy. According to some scholars, there is ‘no evidence that Gazelles are overrepresented in high- technology industries’ (Henrekson and Johansson, 2010, p.240). Despite their strong prioritisation by policy makers, the reality is that the representation of technology based firms (TBFs) in the population of HGFs is roughly on a par with their proportion in the economy (Mason and Brown, forthcoming). In view of these twin priorities of promoting high growth in general and high tech firms in particular, Scottish Enterprise commissioned further research to explore HGFs, especially in high tech areas of the economy. The objectives of this paper are twofold: to provide an update on the level of HGFs in Scotland and to assess the population of TBFs in Scotland. The paper proceeds as follows. First, the terms high growth and technology-based enterprises are defined. Second, the methodology is outlined. Third, the aggregate evidence on the levels of HGFs in Scotland is presented. Fourth, the population of TBFs in Scotland, including analysis of high growth TBFs is profiled. Fifth, some of the key characteristics of high growth TBFs in Scotland are examined. Sixth, some of features of these firms which were captured during the qualitative part of this research process are summarised. The paper finishes with some brief conclusions and issues for further research

    Price Impact and Survival of Irrational Traders

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    Milton Friedman argued that irrational traders will consistently lose money, won’t survive and, therefore, cannot influence long run equilibrium asset prices. Since his work, survival and price impact have been assumed to be the same. In this paper, we demonstrate that survival and price impact are two independent concepts. The price impact of irrational traders does not rely on their long-run survival and they can have a significant impact on asset prices even when their wealth becomes negligible. We also show that irrational traders ’portfolio policies can deviate from their limits long after the price process approaches its long-run limit. We show, in contrast to a partial equilibrium analysis, these general equilibrium considerations matter for the irrational traders long-run survival. In sum, we explicitly show that price impact can persist whether or not the irrational traders survive.

    Rebellious uniform

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    In this thesis, I focus on adolescent teens at Kingswood College High School, where I am currently employed as a student assistant in Grahamstown. I form part of a networked hierarchy at Kingswood College whereby I am expected to perform duties which require me to uphold discipline, forge respect and act as a mentor to students. Within this complex role I am mindful of the power dynamics within the school and my focus is on how the students at Kingswood College in some instances challenge them. Regulations in regard to uniforms and in regard to the arrangement of each learner’s belongings insist on the sublimation/sacrificing of an individual identity in favour of an institutional one. Thus tiny departures from those norms, slight transgressions, might be understood as small rebellions which the boarder stages against disciplinary structures and the conformity demanded of him or her. I am particularly interested in these transgressions. In this thesis I attempt to unravel the complexities associated with such idiosyncrasies and how they play out amongst adolescent teens

    Using Concept Inventories to Measure Understanding

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    Measuring understanding is notoriously difficult. Indeed, in formulating learning outcomes the word “understanding” is usually avoided, but in the sciences, developing understanding is one of the main aims of instruction. Scientific knowledge is factual, having been tested against empirical observation and experimentation, but knowledge of facts alone is not enough. There are also models and theories containing complex ideas and inter-relationships that must be understood, and considerable attention has been devoted across a range of scientific disciplines to measuring understanding. This case study will focus on one of the main tools employed: the concept inventory and in particular the Force Concept Inventory. The success of concept inventories in physics has spawned concept inventories in chemistry, biology, astronomy, materials science and maths, to name a few. We focus here on the FCI, ask how useful concept inventories are for evaluating learning gains. Finally, we report on recent work by the authors to extend conceptual testing beyond the multiple-choice format
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