Contributions of experimental mouse models to the understanding of African trypanosomiasis.

in Trends in Parasitology (2008), 24(9), 411-8

African trypanosomiasis is the collective name for a wide variety of trypanosome infections that affect humans and livestock. In recent years, experimental mice infection models have provided new insights ... [more ▼]

African trypanosomiasis is the collective name for a wide variety of trypanosome infections that affect humans and livestock. In recent years, experimental mice infection models have provided new insights into both human and animal trypanosomiasis. Mouse models seem to be a valuable and versatile tool in trypanosomiasis-associated pathology and immunology research and highlight the variety shown by African trypanosomiases. Indeed, inbred mouse strains have enabled the study of genetic determinants of susceptibility and of the roles of anti-parasite antibodies, inflammatory mediators and anti-inflammatory mediators for each trypanosome species. Remarkable advances relating to the encephalitic stage of sleeping sickness have also been achieved thanks to murine models. The different contributions of murine models to the African trypanosomiases knowledge are presented here. Future search directions are finally proposed, with respect to mouse model opportunities and limitations. [less ▲]

Contributions of the driven process and the loading-unloading process during substorms: A study based on the IMAGE-SI12 imager

in Journal of Geophysical Research (2009), 114

Substorm energetics has been shown to have two components, the "loading-unloading'' component releasing energy previously stored in the tail and the "directly driven'' component dissipating simultaneously ... [more ▼]

Substorm energetics has been shown to have two components, the "loading-unloading'' component releasing energy previously stored in the tail and the "directly driven'' component dissipating simultaneously fed solar wind energy. Previous studies disagree about the relative importance of each process. The SI12 spectral imager onboard the IMAGE satellite provides images of the Doppler-shifted Lyman alpha auroral emission at 121.8 nm every 2 min. It has been used to determine the auroral intensity during substorms, which may be compared to the solar wind characteristics and interplanetary magnetic field components before and/or after substorm onsets. In this study, we analyze 256 substorms between June 2000 and December 2002, which satisfy criteria relative to the viewing conditions. We compare the mean nightside intensity during the expansion phase with the magnetic open flux, the epsilon parameter, and other coupling functions (used as proxies of transfer of solar wind energy to the magnetosphere) integrated over the growth phase or the expansion phase. The mean auroral intensity during the expansion phase correlates well with coupling functions integrated over the growth phase. We also find that the correlation between the auroral precipitation during the expansion phase and the coupling functions integrated over the expansion phase is lower but still significant. This implies that, even though both mechanisms contribute to the energy precipitated during substorms, the loading-unloading process is statistically dominant. [less ▲]

Contributions théorique et expérimentale au calcul de la résistance à l'avancement des convois poussés en navigation dans les voies d'eau de sections limitées

in Annales des Travaux Publics de Belgique = Tijdschrift der Openbare Werken van Belgie (1977), (1 et 2), 77

Contributions to Batch Mode Reinforcement Learning

Doctoral thesis (2011)

This dissertation presents various research contributions published during these four years of PhD in the field of batch mode reinforcement learning, which studies optimal control problems for which the ... [more ▼]

This dissertation presents various research contributions published during these four years of PhD in the field of batch mode reinforcement learning, which studies optimal control problems for which the only information available on the system dynamics and the reward function is gathered in a set of trajectories. We first focus on deterministic problems in continuous spaces. In such a context, and under some assumptions related to the smoothness of the environment, we propose a new approach for inferring bounds on the performance of control policies. We also derive from these bounds a new inference algorithm for generalizing the information contained in the batch collection of trajectories in a cautious manner. This inference algorithm as itself lead us to propose a min max generalization framework. When working on batch mode reinforcement learning problems, one has also often to consider the problem of generating informative trajectories. This dissertation proposes two different approaches for addressing this problem. The first approach uses the bounds mentioned above to generate data tightening these bounds. The second approach proposes to generate data that are predicted to generate a change in the inferred optimal control policy. While the above mentioned contributions consider a deterministic framework, we also report on two research contributions which consider a stochastic setting. The first one addresses the problem of evaluating the expected return of control policies in the presence of disturbances. The second one proposes a technique for selecting relevant variables in a batch mode reinforcement learning context, in order to compute simplified control policies that are based on smaller sets of state variables. [less ▲]

Contributions to Constitutive Laws of Metals: Micro-Macro and Damage Models (Part A & B)

Post doctoral thesis (2001)

Contributions to early land plant research (XIV IBC).

in Review of Palaeobotany and Palynology (2001), 116

Contributions to recent advances in the field of steel joints. Column bases and further configurations for beam-to-column joints and column bases

Post doctoral thesis (1997)

Contributions to the development of a test-day model adjusted to New Zealand dairy cattle

Master's dissertation (2004)

A test-day model was developed in order to study the feasibility and the usefulness of a random regression test-day model based on dairy cattle data from New Zealand. (Co)variance components were ... [more ▼]

A test-day model was developed in order to study the feasibility and the usefulness of a random regression test-day model based on dairy cattle data from New Zealand. (Co)variance components were estimated first within breeds then across breeds for Holstein-Friesian and Jersey animals. Results from single breed analysis showed that there are several differences between the two main breeds of dairy cattle in New Zealand. This was confirmed with the genetic correlations below one (r²= 0.926 for milk in first lactation) for breed specific additive genetic effects provided by the across breeds analysis. The specificity of the model used was first the capacity for taking account of these differences between breeds since more than one third of the dairy population are crossbred; and secondly the estimation of different breeding values considering each animal as a potential mate within each of the two breeds. From genetic evaluations, ranking changes in sires were observed by using the model with breed specific additive genetic effects and a model assuming the same breed composition for all animals. This first investigation showed the opportunity to carry on more research in the way to develop an accurate test-day model permitting to evaluate the crossbred dairy cattle of New Zealand and to perform an optimal selection of animals in function of the mating strategy to apply. [less ▲]

Contributions to the modelling of fires in buildings and their effects on structures

Scientific conference (1998, July 24)

Contributor to Small Animal Ophthalmology, 4th Edition - A Problem-Oriented Approach (DVD)

in R.L. Peiffer; S.M. Petersen-Jones (Eds.) Small Animal Ophthalmology, 4th Edition - A Problem-Oriented Approach (2009)