5,568 research outputs found

    Woodland clearance in the Mesolithic: the social aspects.

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    Did Mesolithic people regard the woodland as a wilderness or park? Previous models have portrayed the hunter-gatherers of the Mesolithic as in tune with nature and making use of clearings to attract game. Using equally valid analogies, the authors propose a more hostile landscape that was conceived and managed with clearings and paths to help allay its menacing character

    FORC Analysis of homogeneous nucleation in the two-dimensional kinetic Ising model

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    The first-order reversal curve (FORC) method is applied to the two-dimensional kinetic Ising model. For the system size and magnetic field chosen, the system reverses by the homogeneous nucleation and growth of many droplets. This makes the dynamics of reversal nearly deterministic, in contrast to the strongly disordered systems previously studied by the FORC method. Consequently, the FORC diagrams appear different from those obtained in previous studies. The Kolmogorov-Johnson-Mehl-Avrami (KJMA) theory of phase transformation by nucleation and growth is applied to the system. Reasonable agreement with the Monte Carlo simulations is found, and the FORC method suggests how the KJMA theory could be extended.Comment: 3 pages, 2 figures, presented at 2004 MMM meeting, to appear in conference proceedings in J. Appl. Phys. (May 2005); rephrased several section

    Persistence and Academic Success in University

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    We use a unique set of linked administrative data sets to explore the determinants of persistence and academic success in university. The explanatory power of high school grades greatly dominates that of other variables such as university program, gender, and neighbourhood and high school characteristics. Indeed, high school and neighbourhood characteristics, such as average standardized test scores for a high school or average neighbourhood income, have weak links with success in university.University Success, High School, Neighbourhood

    Persistence and Academic Success in University

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    We use a unique set of linked administrative data sets to explore the determinants of persistence and academic success in university. The explanatory power of high school grades greatly dominates that of other variables such as university program, gender, and neighbourhood and high school characteristics. Indeed, high school and neighbourhood characteristics, such as average standardized test scores for a high school or average neighbourhood income, have weak links with success in university.university success, high school, neighbourhood.

    Financial services used by small businesses: evidence from the 1998 survey of small business finances

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    Using newly available data from the 1998 Survey of Small Business Finances, this article offers preliminary findings regarding the characteristics of small businesses in the United States and their use of credit and other financial services. The main goals of the survey are to provide information on credit accessibility for small businesses, their use of financial services, and the sources of those services. The survey also provides a general-purpose database that can be used to study small business financing. Preliminary findings suggest that although the financial landscape has changed markedly since the previous survey in 1993, financing patterns and the use of particular suppliers have not.Small business ; Financial services industry

    An experience of modularity through design

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    We aim to utilise the experiences of a marine industry-based design team to determine the need for research into a modular design methodology in an industrial environment. In order to achieve this we couple the outcome of a current design project with the findings of a recent literature survey with the objectives of firstly, clarifying why a methodology is required and, secondly, defining the key elements which the methodology would have to realise or address. The potential benefits of modularity have long been recognised in the shipbuilding industry. Many shipbuilders adopt a 'module' approach to ship construction whereby the ship structure is separated into a number of large structural 'blocks' to ease manufacture and manoeuvrability during construction. However, as understanding of the capabilities of modularity as a design tool develops there is increased interest in capitalising on the differing life phase benefits of modularity such as reduced design costs and time, increased ease of maintenance, upgrade, re-use, redesign and standardisation across individual products and product families. This is especially pertinent in naval shipbuilding where the maintenance of a class of ship requires that all previously designed ships in that class must be of similar outfitting and must be able to interface with the new ship, in terms of propulsion, weapons, communications and electronics, and thus often require some form of retrofit. Therefore, many shipbuilders are moving from viewing modularity as a purely 'manufacturing' principle to a design centred principle. However, as noted by Chang and Ward 'none of the design theories or tools in the mechanical world serves as an articulate procedure for designers to follow in practising modular design'. Thus, despite the identification of a need to introduce modular principles at an earlier stage than detail design and construction, there is little aid in the form of tools, techniques and methodologies for designers in practice

    Intravenous conscious sedation in patients under 16 years of age. Fact or fiction?

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    Recently published guidelines on the use of conscious sedation in dentistry have published varying recommendations on the lower age limit for the use of intravenous conscious sedation. There are a large number of dentists currently providing dental treatment for paediatric patients under intravenous conscious sedation. The 18 cases reported here (age range 11-15 years), were successfully managed with intravenous conscious sedation. The experience in this paper is not sufficient evidence to recommend the wholesale use of intravenous conscious sedation in patients who are under 16 years. The fact that a range of operators can use these techniques on paediatric patients would suggest that further study should be carried out in this population. The guidance should be modified to say there is insufficient evidence to support the use of intravenous conscious sedation in children, rather than arbitrarily selecting a cut off point at age 16 years

    Two-stream instability in quasi-one-dimensional Bose-Einstein condensates

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    We apply a kinetic model to predict the existence of an instability mechanism in elongated Bose-Einstein condensates. Our kinetic description, based on the Wigner formalism, is employed to highlight the existence of unstable Bogoliubov waves that may be excited in the counterpropagation configuration. We identify a dimensionless parameter, the Mach number at T=0, that tunes different regimes of stability. We also estimate the magnitude of the main parameters at which two-stream instability is expected to be observed under typical experimental conditions
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