Deux séminaires du professeur Andrea Rinaldo, doctorat honoris causa de l'INRS
Récipiendaire d’un doctorat honoris causa de l’INRS en 2014, Andrea Rinaldo est professeur titulaire à l’Université de Padoue en Italie et à l’École Polytechnique Fédérale de Lausanne (EPFL) en Suisse, où il dirige le Laboratoire d’écohydrologie. Il est membre étranger de l’Académie royale des sciences de Suède ainsi que de l’Académie de génie et l’Académie des sciences des États-Unis. Au cours de ses 35 années de carrière, le professeur Rinaldo a réalisé nombreux travaux novateurs sur l’impact des mécanismes de transport orienté sur la géomorphologie, la dynamique des écosystèmes, le transport de solutés, la propagation de maladies et le système d’échange d’eau virtuelle. Il a publié plus de 200 articles dans des revues scientifiques, dont les plus prestigieuses en sciences, en hydrologie et en physique.
Il présentera deux séminaires au centre ETE à Québec
Mardi 21 juin, local 2422, 12h10, sur le thème Hydrologic Controls and Spatially Explicit Modeling of Waterborne Disease
Mercredi 22 juin, local 2422, 12h10, sur le thème Fluvial Geomorphology and Biodiversity
Sur la conférence du 21 juin Hydrologic controls...:
Mathematical models can provide key insights into the course of an ongoing epidemic, potentially aiding real-time emergency management in allocating health care resources and by anticipating the impact of alternative interventions. In this lecture I shall report on two case studies that examine the role of hydrologic and other controls on the spreading of waterborne diseases. In the first case study I will examine the reliability of predictions of the 2010–2011 Haiti cholera outbreak from four independent modeling studies that appeared during the unfolding epidemic. Spatial spread of V. cholerae and mechanisms of cholera transmission account for the dynamics of susceptible and infected individuals within different local human communities. To explain resurgences of the epidemic, inclusion of waning immunity and a mechanism explicitly accounting for rainfall as a driver of enhanced disease transmission is needed. A generalized model for Haitian epidemic cholera and the related uncertainty is proposed and applied to the year-long dataset of reported cases.
Big data, in particular mobile phone data, is expected to revolutionize epidemiology, yet its full potential is still untapped. In the second case study a dataset of mobile phone records of approximately 150,000 users in Senegal is analyzed to extract the evolution of human mobility fluxes and directly incorporate them into a spatially explicit, dynamic epidemiological framework. Our model is applied to the 2005 cholera outbreak in Senegal that totaled more than 30,000 reported cases. The findings highlight the major influence that a mass gathering, which took place during the initial phase of the epidemic, has had on the course of the disease. Such an effect could not be explained by classic, static approaches describing human mobility. Model results also show how concentrated efforts of disease control in a transmission hotspot can have an important effect on the large-scale progression of a cholera outbreak. These two case studies demonstrate how mathematical modeling of large-scale outbreaks emerges as an essential component of future waterborne disease epidemic control.
Sur la conférence du 22 juin, sur Fluvial geomorphology...
How biodiversity changes with elevation has long attracted the interest of ecologic research because it provides key clues to how biota respond to geophysical drivers. Experimental evidence reveals that biodiversity often peaks at intermediate elevations of any rugged landscape, and yet a clear explanation is still elusive. In this lecture I shall report on a factor that has been overlooked to date: Fluvial landscapes hold fractal properties with elevational bands forming habitat patches that are characterized by different areal extent and connectivity. When the geometry of real landscapes is taken into account, ecological dynamics naturally produce mid-peak elevational gradients of species richness regardless of other altitude-independent drivers. In mountainous landscapes, habitats at different elevations are characterized by different areal extent and connectivity properties that are predicted to be key drivers of biodiversity by e.g. metacommunity theory. However, most previous studies directly correlated species richness to elevational gradients of potential drivers, thus neglecting the interplay between such gradients and the environmental matrix. To single out the role of geomorphology in shaping patterns of species richness, a spatially explicit zero-sum metacommunity model is run on a fluvial landscape where species have an elevation-dependent fitness and otherwise neutral traits. Results show that ecological dynamics over complex terrains lead to the null expectation of a hump-shaped elevational gradient of species richness, a pattern widely observed empirically. Local species richness is found to be related to the landscape elevational connectivity, as quantified by a newly proposed metric that applies tools of complex network theory to measure the closeness of a site to others with similar habitat. The theoretical results suggest clear geomorphic controls on elevational gradients of species richness and support the use of the landscape elevational connectivity as a null model for the analysis of the distribution of biodiversity. Other examples will be presented specifically focused on : i) the role of the topology of the substrate in shaping the features of biodiversity, and in particular that of directional dispersal ; and ii) large-scale outcomes of the application of metacommunity models on a fluvial network, specifically that of the Mississippi-Missouri river system. It is argued that these results further biodiversity theory and our understanding of the distribution of life on Earth.
