In: Proc. R. Soc. B, 2016, vol. 283, no. 1824, p. 20152702
Networks play a prominent role in the study of complex systems of interacting entities in biology, sociology, and economics. Despite this diversity, we demonstrate here that a statistical model decomposing networks into matching and centrality components provides a comprehensive and unifying quantification of their architecture. The matching term quantifies the assortative structure in which node...
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In: PLoS ONE, 2015, vol. 10, no. 3, p. e0118238
The plant hormone auxin plays a central role in growth and morphogenesis. In shoot apical meristems, auxin flux is polarized through its interplay with PIN proteins. Concentration-based mathematical models of the flux can explain some aspects of phyllotaxis for the L1 surface layer, where auxin accumulation points act as sinks and develop into primordia. The picture differs in the interior of the...
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In: Behavioural Brain Research, 2011, vol. 219, no. 1, p. 132-141
We aimed to determine whether human subjects’ reliance on different sources of spatial information encoded in different frames of reference (i.e., egocentric versus allocentric) affects their performance, decision time and memory capacity in a short-term spatial memory task performed in the real world. Subjects were asked to play the Memory game (a.k.a. the Concentration game) without an...
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In: Advances in Applied Probability, 2011, vol. 43, no. 2, p. 375-398
Organisms adapt to fluctuating environments by regulating their dynamics, and by adjusting their phenotypes to environmental changes. We model population growth using multitype branching processes in random environments, where the offspring distribution of some organism having trait t ∈ T in environment e ∈ E is given by some (fixed) distribution...
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In: BMC Genomics, 2011, vol. 12, p. 181
Background: Multiplex experimental assays coupled to computational predictions are being increasingly employed for the simultaneous analysis of many specimens at the genome scale, which quickly generates very large amounts of data. However, inferring valuable biological information from the comparisons of very large genomic datasets still represents an enormous challenge.Results: As a study...
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In: Random Structures & Algorithms, 2010, vol. 37, no. 1, p. 67–84
Polygon spaces such as $ M_{\ell} = \{ (u_{1,\ldots,} u_{n})\; \epsilon \; S^{1}\times \ldots S^{1}, \sum \nolimits^{n}_{i=1}\;l_{i}u_{i} = 0 \}/SO(2) $, or the three-dimensional analogs Nℓ play an important rle in geometry and topology, and are also of interest in robotics where the li model the lengths of robot arms. When n is large, one can assume that each li is a positive real valued...
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In: The American Naturalist, 2010, vol. 176, no. 2, p. 170-177
Several stochastic models have tried to capture the architecture of food webs. This approach is interesting, but it is limited by the fact that different assumptions can yield similar results. To overcome this limitation, we develop a purely statistical approach. Body size in terms of an optimal ratio between prey and predator is used as explanatory variable. In 12 observed food webs, this model...
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In: Insurance: Mathematics and Economics, 2009, vol. 45, no. 3, p. 374-381
In the classical risk model, we prove the weak convergence of a sequence of empirical finite-time ruin probabilities. In an earlier paper (see Loisel et al., (2008)), we proved an equivalent result in the special case where the initial reserve is zero, and checked that numerically the general case seems to be true. In this paper, we prove the general case (with a nonnegative initial reserve),...
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In: Insurance: Mathematics and Economics, 2008, vol. 42, no. 2, p. 746-762
We consider the classical risk model and carry out a sensitivity and robustness analysis of finite-time ruin probabilities. We provide algorithms to compute the related influence functions. We also prove the weak convergence of a sequence of empirical finite-time ruin probabilities starting from zero initial reserve toward a Gaussian random variable. We define the concepts of reliable finite-time...
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In: BMC Bioinformatics, 2007, vol. 8, p. 131
Background: PCR has the potential to detect and precisely quantify specific DNA sequences, but it is not yet often used as a fully quantitative method. A number of data collection and processing strategies have been described for the implementation of quantitative PCR. However, they can be experimentally cumbersome, their relative performances have not been evaluated systematically, and they...
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