Catastrophe risks: the case of seisms

Catastrophes and risks have had a great influence on the evolution of human development. We analyze behaviors in front of risks, then we consider some basic principles that have guided private and public behaviors. Managing risks has become a specialty for finance and insurance, but they are not the only institutions that allow to confront them. We conclude on an example of how public funds, private insurance and reinsurance companies can work together and use financial markets in order to cover financial risks due to seisms.

Top-Flavoured Dark Matter in Dark Minimal Flavour Violation

We study a simplified model of top-flavoured dark matter in the framework of Dark Minimal Flavour Violation. In this setup the coupling of the dark matter flavour triplet to right-handed up-type quarks constitutes the only new source of flavour and CP violation. The parameter space of the model is restricted by LHC searches with missing energy final states, by neutral $D$ meson mixing data, by the observed dark matter relic abundance, and by the absence of signal in direct detection experiments. We consider all of these constraints in turn, studying their implications for the allowed parameter space. Imposing the mass limits and coupling benchmarks from collider searches, we then conduct a combined analysis of all the other constraints, revealing their non-trivial interplay. Especially interesting is the combination of direct detection and relic abundance constraints, having a severe impact on the structure of the dark matter coupling matrix. We point out that future bounds from upcoming direct detection experiments, such as XENON1T, XENONnT, LUX-ZEPLIN, and DARWIN, will exclude a large part of the parameter space and push the DM mass to higher values.Comment: 34 pages, 23 figures. v2: clarifying comments and few references added, matches published versio

Comparison of circular orbit and Fourier power series ephemeris representations for backup use by the upper atmosphere research satellite onboard computer

The Upper Atmosphere Research Satellite (UARS) is a three-axis stabilized Earth-pointing spacecraft in a low-Earth orbit. The UARS onboard computer (OBC) uses a Fourier Power Series (FPS) ephemeris representation that includes 42 position and 42 velocity coefficients per axis, with position residuals at 10-minute intervals. New coefficients and 32 hours of residuals are uploaded daily. This study evaluated two backup methods that permit the OBC to compute an approximate spacecraft ephemeris in the event that new ephemeris data cannot be uplinked for several days: (1) extending the use of the FPS coefficients previously uplinked, and (2) switching to a simple circular orbit approximation designed and tested (but not implemented) for LANDSAT-D. The FPS method provides greater accuracy during the backup period and does not require additional ground operational procedures for generating and uplinking an additional ephemeris table. The tradeoff is that the high accuracy of the FPS will be degraded slightly by adopting the longer fit period necessary to obtain backup accuracy for an extended period of time. The results for UARS show that extended use of the FPS is superior to the circular orbit approximation for short-term ephemeris backup

Executive Compensation and Analyst Guidance: The Link between CEO Pay and Expectations Management

During the last decade, a surprisingly high percentage of U.S. companies has fulfilled or beaten analysts’ earnings per share forecasts. One of the most frequently cited reasons for this growing tendency is a change in the nature of U.S. executive compensation structure. As stock options have become an increasingly important part of executive compensation, the preservation or enhancement of short term stock value around the earnings announcement has become a priority for managers. Besides earnings management, a widespread way to meet analyst expectations is to inject pessimism into their forecasts by providing analysts with negative clues, or so-called downward guidance. This paper is the first to investigate the relationship between the practice of analyst guidance and executive compensation packages. We document a strong link between expectations management and the relevant options component of CEO compensation, bonus plan payments, and the value of the firm's shares owned by its managing CEO. In a second set of tests, we show that firms that meet or beat analyst forecasts at the earnings announcement generate positive abnormal returns, which are significantly lower for firms suspected of managing expectations.Analyst guidance; Earnings surprise; Executive compensation; Stock options

Valuing future cash flows with non separable discount factors and non additive subjective measures: Conditional Choquet Capacities on Time and on Uncertainty

We consider future cash flows that are contingent both on dates in time and on uncertain states. The decision maker (DM) values the cash flows according to its decision criterion: Here the payoffs’ expectation with respect to a capacity measure. The subjective measure grasps the DM’s behaviour in front of the future, in the spirit of de Finetti’s (1930) and of Yaari’s (1987) Dual Theory in the case of risk. Decomposition of the criterion into two criteria that represent the DM’s preferences on uncertain payoffs and time contingent payoffs are derived from Ghirardato’s (1997) results. Conditional Choquet integrals are defined by dynamic consistency requirements and conditional capacities are derived, under some conditions on information. In contrast with other models referring to dynamic consistency, ours doesn’t collapse into a linear one because it violates a weak version of consequentialism.

A conceptual framework to assess vulnerability. Application to global change stressors on South Indian farmers

The objectives of the paper are (1) to apply Füssels (2007) conceptual framework of vulnerability to a concrete ongoing research and (2) to discuss on the resulting choice of an adequate vulnerability approach. The research aims at assessing the vulnerability of South Indian farmers to global change at two periods of time: medium term (2030-2040) to account for rapid global economic changes, and long term (2045-2065) to account for climate change and variability. The term vulnerability is dened in so many ways that its use has become controversial. Fussel proposed an original conceptual framework of vulnerability based on a common and transversal terminology understandable whatever the scientic domain of concern. This conceptual framework relies on the description of six dimensions of the vulnerability concept. The rst four dimensions describes the vulnerable situation and the last two dimensions explain the factors of vulnerability. Füssel argues that with this set of dimensions, it is possible to class any conceptual approach of vulnerability found in the literature. After the six dimensions were adapted to South Indian farmers vulnerability, the use of a cross-scale integrated approach of vulnerability appears clearly as the most appropriate.[...]