311 research outputs found

    Revisiting linear augmentation for stabilizing stationary solutions: potential pitfalls and their application

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    Linear augmentation has recently been shown to be effective in targeting desired stationary solutions, suppressing bistablity, in regulating the dynamics of drive response systems and in controlling the dynamics of hidden attractors. The simplicity of the procedure is the highlight of this scheme but at the same time questions related to its general applicability still need to be addressed. Focusing on the issue of targeting stationary solutions, this work demonstrates instances where the scheme fails to stabilize the required solutions and leads to other complicated dynamical scenarios. Appropriate examples from conservative as well as dissipative systems are presented in this regard and potential applications for relevant observations in dissipative predator--prey systems are also discussed.Comment: updated version with title change, additional figures, text and explanation

    Early warning signal for interior crises in excitable systems

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    The ability to reliably predict critical transitions in dynamical systems is a long-standing goal of diverse scientific communities. Previous work focused on early warning signals related to local bifurcations (critical slowing down) and non-bifurcation type transitions. We extend this toolbox and report on a characteristic scaling behavior (critical attractor growth) which is indicative of an impending global bifurcation, an interior crisis in excitable systems. We demonstrate our early warning signal in a conceptual climate model as well as in a model of coupled neurons known to exhibit extreme events. We observed critical attractor growth prior to interior crises of chaotic as well as strange-nonchaotic attractors. These observations promise to extend the classes of transitions that can be predicted via early warning signals.Comment: 6 pages, 4 figure

    PRESENCE OF ANALYSTS BEFORE IPO AND UNDERPRICING: A META-ANALYSIS

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    The effect of analyst presence on underpricing has shown a contrasting result. By synthesizing the result using meta-analysis for twelve studies with more than 20400 firms we found conclusive evidence of the relation between analyst presence and underpricing of IPOs. With the increase in analyst presence by 1% the IPO underpricing increases by 4.9%. Moreover, meta-regression between effect size and moderator variables found the significant and positive role of the reputed underwriter to increase underpricing when the IPO has coverage of analysts. Our results are striking for the US market IPOs in which reputed underwriters as moderator affect underpricing significantly and positively which shows reputation increase information asymmetry. Whereas in emerging markets IPOs reputed underwriters increase market efficiency and information symmetry

    Determination of the relative concentrations of rare earth ions by x-ray absorption spectroscopy: Application to terbium mixed oxides

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    A method, based on X-ray absorption spectroscopy (XAS) in the range 0.8–1.5 keV, to determine the relative amounts of rare earth ions in different valencies is explained and tested for the case of terbium mixed oxides. The results are in agreement with those obtained by existing analytical methods. The XAS method is advantageous in that it can be applied where other, conventional, methods break down

    Just wrong? Or just WEIRD? Investigating the prevalence of moral dumbfounding in non-Western samples

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    Moral dumbfounding is the phenomenon that is observed when people defend a moral judgement even though they cannot provide a reason for this judgement. Dumbfounded responding may include admitting to not having reasons, or the use of unsupported declarations (e.g., “It’s just wrong”) as justification for a judgement. Published evidence for dumbfounding has drawn exclusively on samples of WEIRD backgrounds (Western, educated, industrialised, rich, and democratic), and it remains unclear whether the phenomenon is generalilsable to other populations. In three studies we apply a standardised moral dumbfounding task, and show evidence for moral dumbfounding in a Chinese sample (Study 1), an Indian sample (Study 2), and a mixed sample primarily from North Africa and the Middle East (MENA region, Study 3)

    Protection of stainless-steels against corrosion in sulphidizing environments by Ce oxide coatings: X-ray absorption and thermogravimetric studies

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    In this paper a study is reported concerning ceramic coatings containing cerium oxide, prepared by the sol-gel method, used to protect Incoloy 800H against sulphidation. When the coating is sintered in air at 850°C good protection is obtained. In an X-ray absorption spectroscopic study of the coatings it was observed that the best protective coating contains all cerium as CeIV after pretreatment. After sulphidizing cerium was reduced to CeIII. Possible mechanisms to explain the protective properties are discussed
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