Common components of risk and uncertainty attitudes across contexts and domains: evidence from 30 countries

Attitudes towards risk and uncertainty have been indicated to be highly context-dependent, and to be sensitive to the measurement technique employed. We present data collected in controlled experiments with 2,939 subjects in 30 countries measuring risk and uncertainty attitudes through incentivized measures as well as survey questions. Our data show clearly that measures correlate not only within decision contexts or measurement methods, but also across contexts and methods. This points to the existence of one underlying “risk preference”, which influences attitudes independently of the measurement method or choice domain. We furthermore find that answers to a general and a financial survey question correlate with incentivized lottery choices in most countries. Incentivized and survey measures also correlate significantly between countries. This opens the possibility to conduct cultural comparisons on risk attitudes using survey instruments

Accommodating stake effects under prospect theory

One of the stylized facts underlying prospect theory is a four-fold pattern of risk preferences. People have been shown to be risk seeking for small probability gains and large probability losses, while being risk averse for large probability gains and small probability losses. Another fourfold pattern of risk preferences over outcomes, postulated by Harry Markowitz in 1952, has received much less attention and is currently not integrated into prospect theory. In two experiments, we show that risk preferences may change over outcomes. While we find people to be risk seeking for small outcomes, this turns to risk neutrality and later risk aversion as stakes increase. We then show how a one-parameter logarithmic utility function fits such stake effects significantly better under prospect theory than the power or exponential functions mostly used when fitting prospect theory models. We further investigate the extent to which the use of ill-suited functional forms to represent utility may result in violations of prospect theory, and whether such violations disappear when using logarithmic utility

Differential Effects of Bartonella henselae on Human and Feline Macro- and Micro-Vascular Endothelial Cells

Bartonella henselae, a zoonotic agent, induces tumors of endothelial cells (ECs), namely bacillary angiomatosis and peliosis in immunosuppressed humans but not in cats. In vitro studies on ECs represent to date the only way to explore the interactions between Bartonella henselae and vascular endothelium. However, no comparative study of the interactions between Bartonella henselae and human (incidental host) ECs vs feline (reservoir host) ECs has been carried out because of the absence of any available feline endothelial cell lines

Your money and your life: risk attitudes over gains and losses

Prospect theory is the most influential descriptive alternative to the orthodox model of rational choice under risk and uncertainty, in terms of empirical analyses of some of its principal parameters and as a consideration in behavioural public policy. Yet the most distinctive implication of the theory – a fourfold predicted pattern of risk attitudes called the reflection effect – has been infrequently studied and with mixed results over money outcomes, and has never been completely tested over health outcomes. This article reports tests of reflection over money and health outcomes defined by life years gained from treatment. With open valuation exercises, the results suggest qualified support for the reflection effect over money outcomes and strong support over health outcomes. However, in pairwise choice questions, reflection was substantially ameliorated over life years, remaining significant only for treatments that offered short additional durations of life

Luminescent properties of Eu-doped calcium aluminosilicate glass-ceramics: A potential tunable luminophore

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Luminescent properties of Eu-doped calcium aluminosilicate glass-ceramics: A potential tunable luminophore

International audienceEu-doped calcium aluminosilicate glass-ceramics have been successfully prepared from the initial calcium aluminosilicate glass, containing 50 wt% of silica, under heat-treatment. Structural and optical properties of glass and obtained glass-ceramics were investigated. Control of crystallization using X-ray diffraction and Raman spectroscopy allowed to identify two main crystalline phases: anorthite [CaAl2Si2O8] as the major phase and melilite [Ca2Mg0.75Al0.5Si1.75O7] as the minor phase. Luminescent properties were investigated by emission spectra, lifetime measurements and color point analysis. The Eu3+ ion emission was used as an environment probe in the initial glass and glass-ceramics. Additionally, the broad band emission due to 4f65 d1→4f7 showed that Eu2+ is incorporated into the crystalline phases after reduction of Eu3+ during annealing. This incorporation, increasing with time of heat-treatment, enhanced Eu2+ luminescence

Early smoke detection of forest wildfire video using deep belief network

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Early smoke detection of forest wildfire video using deep belief network

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Modélisation numérique de la fragmentation du sommeil par Réseau de neurones artificiels

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