31,674 research outputs found

    Case record analysis

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    It is argued that the determinates of low frequency (less than once an hour) challenging behavior are likely to be more complex than those of high frequency behavior involving setting events that may not be present when the behavior occurs. The analysis of case records is then examined as a method of identifying possible setting events to low frequency behaviours. It is suggested that time series analysis, correlational analysis and time lag sequential analysis may all be useful methods in the examination of case records

    Causality detection and turbulence in fusion plasmas

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    This work explores the potential of an information-theoretical causality detection method for unraveling the relation between fluctuating variables in complex nonlinear systems. The method is tested on some simple though nonlinear models, and guidelines for the choice of analysis parameters are established. Then, measurements from magnetically confined fusion plasmas are analyzed. The selected data bear relevance to the all-important spontaneous confinement transitions often observed in fusion plasmas, fundamental for the design of an economically attractive fusion reactor. It is shown how the present method is capable of clarifying the interaction between fluctuating quantities such as the turbulence amplitude, turbulent flux, and Zonal Flow amplitude, and uncovers several interactions that were missed by traditional methods.Comment: 26 pages, 14 figure

    Action and semantics of time in agro-ecology

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    In the systemic approach, the system is perceived as an action or a collection of overlapping actions expressed in reference to Time, Space, and Morphology (or Energy). When the system is studied by different disciplines, the referentials differ, as well as the semantics of terms used to describe the action. In order to establish the vocabulary of a collection of actions involving several disciplines, we propose a formal method for describing each action. The linguistic-based method enables (i) transcription of the literal description of an action in a semantic network, and (ii) building of a vocabulary in a formal setting. The method is illustrated through a complex biological system, i.e. the mutualistic relationship between two vine pests, while focusing particularly on temporality. The method provides a support for implementing multidisciplinary around a complex system. (Résumé d'auteur

    Social protection and economic growth in the Sudan: Trends, perspectives, cointegration and causality

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    This paper takes into account the recent role of social protection on economic growth as a socio-economic-political stabilizer. Social protection outcome in Sudan is influenced by limited targeting actions with very low interventions between results in economic growth and accesses to basic social services. These may affects the social protection contributes to the process of development in the Sudan during the period under consideration. The results show that more social spending increase output which enhances GDP per capita growth by 0.5% with 3.1% towards convergence equilibrium in the long run. Moreover, universal approach and expanded cover to social protection services which aim at building a social protection as a productive factor may have contributed to enhancing income security, education and health outcomes, reducing the poverty, income inequality, socio-political stability, encouraged poor productive activities and enhancing economic growth lead to sustainable development.Social Protection, Growth, Cointegration, causality, Sudan

    Understanding the effects of violent video games on violent crime

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    Psychological studies invariably find a positive relationship between violent video game play and aggression. However, these studies cannot account for either aggressive effects of alternative activities video game playing substitutes for or the possible selection of relatively violent people into playing violent video games. That is, they lack external validity. We investigate the relationship between the prevalence of violent video games and violent crimes. Our results are consistent with two opposing effects. First, they support the behavioral effects as in the psychological studies. Second, they suggest a larger voluntary incapacitation effect in which playing either violent or non-violent games decrease crimes. Overall, violent video games lead to decreases in violent crime. --Video Games,Violence,Crime

    Constructing Time Machines

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    The existence of time machines, understood as spacetime constructions exhibiting physically realised closed timelike curves (CTCs), would raise fundamental problems with causality and challenge our current understanding of classical and quantum theories of gravity. In this paper, we investigate three proposals for time machines which share some common features: cosmic strings in relative motion, where the conical spacetime appears to allow CTCs; colliding gravitational shock waves, which in Aichelburg-Sexl coordinates imply discontinuous geodesics; and the superluminal propagation of light in gravitational radiation metrics in a modified electrodynamics featuring violations of the strong equivalence principle. While we show that ultimately none of these constructions creates a working time machine, their study illustrates the subtle levels at which causal self-consistency imposes itself, and we consider what intuition can be drawn from these examples for future theories.Comment: 36 pages, 14 figures, TeX with harvmac; Review article prepared for Int. J. Mod. Phys.
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