3,591 research outputs found

    The Evolution of Reaction-diffusion Controllers for Minimally Cognitive Agents

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    Random spherical hyperbolic diffusion

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    The paper starts by giving a motivation for this research and justifying the considered stochastic diffusion models for cosmic microwave background radiation studies. Then it derives the exact solution in terms of a series expansion to a hyperbolic diffusion equation on the unit sphere. The Cauchy problem with random initial conditions is studied. All assumptions are stated in terms of the angular power spectrum of the initial conditions. An approximation to the solution is given and analysed by finitely truncating the series expansion. The upper bounds for the convergence rates of the approximation errors are derived. Smoothness properties of the solution and its approximation are investigated. It is demonstrated that the sample H\"older continuity of these spherical fields is related to the decay of the angular power spectrum. Numerical studies of approximations to the solution and applications to cosmic microwave background data are presented to illustrate the theoretical results.Comment: 30 pages, 15 figures. Updated file. Some misprints are correcte

    Evidence on entrepreneurs in the United States: data from the 1989–2004 survey of consumer finances

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    Using data from the Federal Reserve Board’s Survey of Consumer Finances, the authors examine characteristics of entrepreneurs and the businesses they run. Their analysis confirms that business owners are important sources of saving and wealth creation in the U.S. and that they are less risk averse than other wealthy households. This discounts the notion that the wealth of entrepreneurs disproportionately reflects a buildup of precautionary balances to guard against financial risk.Consumer surveys ; Business enterprises

    Multidimensionality of Entrepreneurial Firm-level Processes: Do the Dimensions Covary?

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    Covariance (or not) among the first-order dimensions of firm-level entrepreneurial processes underpins a fundamental and non-trivial difference between the entrepreneurial orientation and entrepreneurial posture constructs. Utilizing a typology developed for multi-dimensional constructs, we operationalized each construct according to its specific conceptualization (relationships among the dimensions) and compared and contrasted each construct in an identical nomological network. Although we found support for both theories, the entrepreneurial orientation construct was more robust in explaining additional variance in growth. Additionally, our findings suggest that the means through which the first-order dimensions are operationalized—latent vs. summates— significantly affect the analysis

    A Basis for Civility

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    Give attention, if you will, to the virtue of civility. In this essay I want to define civility, then give a bit of its history, continue by predicting something of its future, and conclude by explaining civility\u27s true ground, at least as I understand it. We are not here interested in politeness or courtesy, though those meanings of civility may be ancillary to our topic. We are thinking instead about the political realm, and we are aware that many voices have been raised to decry the mean-spirited and vicious nature of politics, both in attaining and using public office. \Vise people warn us that democratic governance depends on a kind of self-control, by which the participants in the process guard it against internal meltdown. We ought to give careful attention to civility, for democracy may depend on it. Readers may find much to which they object in this essay, but they will agree that it marks off an interesting topic for discussion. Suggested corrections, at any point, are welcome. The most important thing comes last, for I hope readers will approve of what I say about the ground of civility even if they disagree with my account of what it is, what its history has been, or what its future may be

    Development of a simulated round of golf

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    Purpose The aim of this study was to develop a laboratory-based treadmill simulation of the on-course physiological demands of an 18-hole round of golf and to identify the underlying physiological responses. Methods Eight amateur golfers completed a round of golf during which heart rate (HR), steps taken, and global positioning system (GPS) data were assessed. The GPS data were used to create a simulated discontinuous round on a treadmill. Steps taken and HR were recorded during the simulated round. Results During the on-course round, players covered a mean (±SD) of 8,251 ± 450 m, taking 12,766 ± 1,530 steps. The mean exercise intensity during the on-course round was 31.4 ± 9.3% of age-predicted heart rate reserve (%HRR) or 55.6 ± 4.4% of age-predicted maximum HR (%HRmax). There were no significant differences between the simulated round and the on-course round for %HRR (P = .537) or %HR max (P = .561) over the entire round or for each individual hole. Furthermore, there were no significant differences between the two rounds for steps taken. Typical error values for steps taken, HR, %HRmax, and %HRR were 1,083 steps, ±7.6 b·min?1, ±4.5%, and ±8.1%, respectively. Conclusion Overall, the simulated round of golf successfully recreated the demands of an on-course round. This simulated round could be used as a research tool to assess the extent of fatigue during a round of golf or the impact of various interventions on golfers
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