Environmental Noise Variability in Population Dynamics Matrix Models

The impact of environmental variability on population size growth rate in dynamic models is a recurrent issue in the theoretical ecology literature. In the scalar case, R. Lande pointed out that results are ambiguous depending on whether the noise is added at arithmetic or logarithmic scale, while the matrix case has been investigated by S. Tuljapurkar. Our contribution consists first in introducing another notion of variability than the widely used variance or coefficient of variation, namely the so-called convex orders. Second, in population dynamics matrix models, we focus on how matrix components depend functionaly on uncertain environmental factors. In the log-convex case, we show that, in a sense, environmental variability increases both mean population size and mean log-population size and makes them more variable. Our main result is that specific analytical dependence coupled with appropriate notion of variability lead to wide generic results, valid for all times and not only asymptotically, and requiring no assumptions of stationarity, of normality, of independency, etc. Though the approach is different, our conclusions are consistent with previous results in the literature. However, they make it clear that the analytical dependence on environmental factors cannot be overlooked when trying to tackle the influence of variability.Comment: 9 page

Preferences Yielding the "Precautionary Effect"

Consider an agent taking two successive decisions to maximize his expected utility under uncertainty. After his first decision, a signal is revealed that provides information about the state of nature. The observation of the signal allows the decision-maker to revise his prior and the second decision is taken accordingly. Assuming that the first decision is a scalar representing consumption, the \emph{precautionary effect} holds when initial consumption is less in the prospect of future information than without (no signal). \citeauthor{Epstein1980:decision} in \citep*{Epstein1980:decision} has provided the most operative tool to exhibit the precautionary effect. Epstein's Theorem holds true when the difference of two convex functions is either convex or concave, which is not a straightforward property, and which is difficult to connect to the primitives of the economic model. Our main contribution consists in giving a geometric characterization of when the difference of two convex functions is convex, then in relating this to the primitive utility model. With this tool, we are able to study and unite a large body of the literature on the precautionary effect

Rationally Biased Learning

Are human perception and decision biases grounded in a form of rationality? You return to your camp after hunting or gathering. You see the grass moving. You do not know the probability that a snake is in the grass. Should you cross the grass - at the risk of being bitten by a snake - or make a long, hence costly, detour? Based on this storyline, we consider a rational decision maker maximizing expected discounted utility with learning. We show that his optimal behavior displays three biases: status quo, salience, overestimation of small probabilities. Biases can be the product of rational behavior

Physics with electroweak penguins at LHCb

Flavour changing neutral currents are only allowed via loop diagrams in the Standard Model (SM). Electroweak penguin processes are therefore sensitive probes for new physics, as physics beyond the Standard Model can enter via virtual particles at the same level as SM physics. The LHCb detector at the LHC with its forward geometry is ideally suited for the analysis of electroweak penguin processes in $B$ meson decays. All analyses are performed with 1 fb$^{-1}$ of collision data recorded at a centre-of-mass energy of 7 TeV in 2011 and constrain new physics models.Comment: Proceedings of CKM 2012, the 7th International Workshop on the CKM Unitarity Triangle, University of Cincinnati, USA, 28 September - 2 October 201

(Ultra)Minor Comics? Opening Up the History of (Post-)Yugoslav and Bulgarian Comics to Outsiders

The last decade saw the publication of more and more monographs (partially) devoted to the history of comics (and/or graphic novels) in smaller or larger geographical/cultural areas around our globe. In this article I first focus on what – if anything – (the relevant chapters in) several of these books tell their readers about the history of comics in the former Republic of Yugoslavia and its successor states, and in Bulgaria, the other Slavic country on the Balkan Peninsula. In doing so, I discuss a (‘Cold War’) misperception about East European comics. In the second part, I probe the usefulness of extending the application range of the terms ‘minor [literatures]’ and ‘ultraminor [literatures]’ to the field of comics, whereupon I put forward some suggestions on how future contributions – scholarly and other – to the cultural transmission or opening up of the history of (post-)Yugoslav and Bulgarian comics, as well as those of countries/nations/language areas with comparable traditions, could look like

The ‘Belgrade Circle’ : Pushkin, Lermontov, Gogol and Tolstoy in Serbian interwar comics

As not everyone knows, the ‘Belgrade Circle’, the collective of comics authors who ushered in the so-called ‘Golden Age of Serbian comics’ (from the 1930s until WW II), had many Russian émigrés among its members. This contribution mainly deals with their practice of adapting the nineteenth-century literary classics of their home country into the comics medium