Choquet Integrals With Respect to Non-Monotonic Set Functions

This paper introduces the signed Choquet integral, i.e., a nonmonotonic generalization of the Choquet integral. Applications to welfare theory, multi-period optimization, and asset pricing are described.Choquet integral;comonotonicity;arbitrage;time preference

Respiratory and systematic humoral and cellular immune response of pigs to a heterosubtypic influenza A virus infection

The level of heterosubtypic immunity (Het-I) and the immune mechanisms stimulated by a heterosubtypic influenza virus infection were investigated in pigs. Pigs are natural hosts for influenza virus and, like humans, they host both subtypes H1N1 and H3N2. Marked Het-I was observed when pigs were infected with H1N1 and subsequently challenged with H3N2. After challenge with H3N2, pigs infected earlier with H1N1 did not develop fever and showed reduced virus excretion compared with non-immune control pigs. In addition, virus transmission to unchallenged group-mates could be shown by virus isolation in the non-immune control group but not in the group infected previously with H1N1. Pigs infected previously with homologous H3N2 virus were protected completely. After challenge with H3N2, pigs infected previously with H1N1 showed a considerable increase in serum IgG titre to the conserved extracellular domain of M2 but not to the conserved nucleoprotein. These results suggest that antibodies against external conserved epitopes can have an important role in broad-spectrum immunity. After primary infection with both H1N1 and H3N2, a long-lived increase was observed in the percentage of CD8 T cells in the lungs and in the lymphoproliferation response in the blood. Upon challenge with H3N2, pigs infected previously with H1N1 again showed an increase in the percentage of CD8 T cells in the lungs, whereas pigs infected previously with H3N2 did not, suggesting that CD8 T cells also have a role in Het-I. To confer broad-spectrum immunity, future vaccines should induce antibodies and CD8 T cells against conserved antigens

Choquet Integrals With Respect to Non-Monotonic Set Functions

This paper introduces the signed Choquet integral, i.e., a nonmonotonic generalization of the Choquet integral. Applications to welfare theory, multi-period optimization, and asset pricing are described.

The midweight method to measure attitudes towards risk and ambiguity

This paper introduces a parameter-free method for measuring the weighting functions of prospect theory and rank-dependent utility. These weighting functions capture risk attitudes, subjective beliefs, and ambiguity attitudes. Our method, called the midweight method, is based on a convenient way to obtain midpoints in the weighting function scale. It can be used both for risk (known probabilities) and for uncertainty (unknown probabilities). The resulting integrated treatment of risk and uncertainty is particularly useful for measuring ambiguity, i.e., the difference between uncertainty and risk. Compared to existing methods to measure weighting functions and attitudes toward uncertainty and ambiguity, our method is more efficient and can accommodate violations of expected utility under risk. An experiment demonstrates the tractability of our method, yielding plausible results such as ambiguity aversion for moderate and high likelihoods but ambiguity seeking for low likelihoods, as predicted by Ellsberg

Can we predict the fate of the Universe?

We re-analyze the question of the use of cosmological observations to infer the present state and future evolution of our patch of the universe. In particular, we discuss under which conditions one might be able to infer that our patch will enter an inflationary stage, as a prima facie interpretation of the Type Ia supernovae and CMB data would suggest. We then establish a `physical' criterion for the existence of inflation, to be contrasted with the more `mathematical' one recently proposed by Starkman et al. \cite{STV}.Comment: 10 LaTeX pages, 4 eps figures, version to appear in Phys. Lett.

Alternatives to Quintessence Model Building

We discuss the issue of toy model building for the dark energy component of the universe. Specifically, we consider two generic toy models recently proposed as alternatives to quintessence models, known as Cardassian expansion and the Chaplygin gas. We show that the former is enteriely equivalent to a class of quintessence models. We determine the observational constraints on the latter, coming from recent supernovae results and from the shape of the matter power spectrum. As expected, these restrict the model to a behaviour that closely matches that of a standard cosmological constant $\Lambda$.Comment: RevTex4; 7 pages, 4 figures. v2: Improved discussion of constraints on Chaplygin gas models. Other clarifications added. Phys Rev. D (in press