Dynamic modeling of a vector-borne disease, from an individual to a metapopulation perspective. Application to plague in central Asia

International audienceBubonic plague, a zoonotic infection that circulates in wild rodents but is transmissible from them to humans through the bites of infected fleas, is not merely of historical interest. It is widespread in the world today and a continuing threat (Stenseth et al. (2008). In the Pre-Balkhash autonomous focus (Kazakhstan, central Asia), the great gerbil Rhombomys opimus is the main reservoir host (Gage and Kosoy, 1995). Davis et al. (2004, 2007) proposed that the family-oriented population structure of the great gerbil and its associated ectoparasite fleas of genus Xenopsylla, along with their seasonally constrained weather-dependent dynamics, is a key factor that determines plague epizootics and plague long-term persistence in rodents in this focus. Yet, the question of the geographical level of plague endemicity, i.e. whether plague can persist in a local autonomous " micro-focus " of minimum size to be determined, or necessarily operates at a larger level, remains poorly understood (Schmid et al., 2012). A knowledge-driven dynamic modeling framework is developed to help answering this question. A spatially explicit agent-based model is first developed, based upon finely described individual processes and interactions rules in the host-vector parasitoid system, derived from literature. From individual-based simulations, we compute population parameters that are used in a second ODE-based model, representing a specified metapopulation structure of burrow systems, each of one inhabited by family groups of great gerbils and their ectoparasites. The individual-based model integrates the seasonality of fleas and great gerbils’ reproduction and daily foraging activity, whereas the second captures the permanent dispersal movement of juvenile great gerbils to form new family groups, through which plague propagates

Une géographie des circuits courts en région PACA : Etat des lieux et potentialités de développement

Short food supply chains are expanding as a multifaceted reality, becoming increasingly structured and supported by local authorities. Prior to consider the structuring of this sector, the purpose of this article is to identify the real development potentials of these Territorial Food Systems: we propose an integrated exploratory multivariate statistics approach that compiles various fields of data acquisition covering the French region Provence-Alpes-Côte d'Azur, resulting in cartography. This methodology leads us to create a typology of the development potentials of short food supply chains and to identify the relevant scales.Les circuits courts alimentaires apparaissent aujourd'hui comme une réalité multiforme, en expansion et de plus en plus structurés, que les collectivités cherchent à accompagner dans leur développement. Avant d'envisager la structuration des filières, il s'agit d'identifier des Systèmes Alimentaires Territoriaux et leurs potentiels de développement : nous proposons une analyse statistique exploratoire multivariée à partir de bases de données existantes couvrant la région Provence-Alpes-Côte d'Azur, et débouchant sur une cartographie. Cette méthodologie nous permet de créer une typologie des potentialités de développement des circuits courts alimentaires

L’exploitation faunique au site BiFk-5 : étude zooarchéologique des restes squelettiques mammaliens

Ce mémoire de maîtrise présente les résultats d’un travail de recherche en zooarchéologie sur la collection faunique du site archéologique BiFk-5, un site de l’île Saint-Bernard dans la municipalité de Châteauguay, sur la rive sud du Saint-Laurent dans la région montréalaise. L’étude se concentre sur les contextes archéologiques d’occupation du XVIIe et XVIIIe siècles, associés historiquement à des activités de traite. L’analyse de 3914 restes squelettiques d’origine mammalienne et l’étude des traces de découpe démontrent une exploitation faunique très diversifiée et axée sur l’exploitation de taxons sauvages. Les restes osseux analysés témoignent de pratiques de subsistance carnée orientées sur la consommation du cochon et du castor du Canada. D’autre part, l’identification de multiples taxons à fourrure dans la collection et la présence de traces de découpe diagnostiques attestent de pratiques régulières d’obtention de fourrures animales sur le site archéologique. La comparaison de l’assemblage faunique de l’île Saint-Bernard à ceux issus de contextes archéologiques similaires permet de constater la contribution importante des espèces sauvages aux pratiques alimentaires carnées des occupants de sites archéologiques à vocation de traite et de reconnaitre une signature zooarchéologique caractéristique de ces lieux.This master's thesis presents the results of a zooarchaeological study on the faunal remains from the BiFk-5 archaeological site of île Saint-Bernard located in the municipality of Châteauguay on the south shore of the Saint-Lawrence, in the greater Montréal region. The study focuses on contexts from the 17th and 18th centuries historically associated with fur trade activities. The analysis of 3914 skeletal remains of mammalian origin and cut marks shows that the site’s occupants exploited a wide range of wild taxa. For their dietary needs, they especially consumed pigs and beavers. In addition, multiple fur bearing taxa and diagnostic cut marks indicate that regular fur extraction activities were carried out on the site. The comparison between the BiFk-5 site faunal assemblage and assemblages from similar archaeological contexts reveals a significant contribution of wild taxa to the dietary practices of trading post inhabitants, enabling us to recognize a zooarchaeological signature characteristic of trading post

The Importance of Being Hybrid for Spatial Epidemic Models: A Multi-Scale Approach

International audienceThis work addresses the spread of a disease within an urban system, defined as a network of interconnected cities. The first step consists of comparing two different approaches: a macroscopic one, based on a system of coupled Ordinary Differential Equations (ODE) Susceptible-Infected-Recovered (SIR) systems exploiting populations on nodes and flows on edges (so-called metapopulational model), and a hybrid one, coupling ODE SIR systems on nodes and agents traveling on edges. Under homogeneous conditions (mean field approximation), this comparison leads to similar results on the outputs on which we focus (the maximum intensity of the epidemic, its duration and the time of the epidemic peak). However, when it comes to setting up epidemic control strategies, results rapidly diverge between the two approaches, and it appears that the full macroscopic model is not completely adapted to these questions. In this paper, we focus on some control strategies, which are quarantine, avoidance and risk culture, to explore the differences, advantages and disadvantages of the two models and discuss the importance of being hybrid when modeling and simulating epidemic spread at the level of a whole urban system

The Importance of Being Hybrid for Spatial Epidemic Models: A Multi-Scale Approach

This work addresses the spread of a disease within an urban system, defined as a network of interconnected cities. The first step consists of comparing two different approaches: a macroscopic one, based on a system of coupled Ordinary Differential Equations (ODE) Susceptible-Infected-Recovered (SIR) systems exploiting populations on nodes and flows on edges (so-called metapopulational model), and a hybrid one, coupling ODE SIR systems on nodes and agents traveling on edges. Under homogeneous conditions (mean field approximation), this comparison leads to similar results on the outputs on which we focus (the maximum intensity of the epidemic, its duration and the time of the epidemic peak). However, when it comes to setting up epidemic control strategies, results rapidly diverge between the two approaches, and it appears that the full macroscopic model is not completely adapted to these questions. In this paper, we focus on some control strategies, which are quarantine, avoidance and risk culture, to explore the differences, advantages and disadvantages of the two models and discuss the importance of being hybrid when modeling and simulating epidemic spread at the level of a whole urban system

Ageing and urban form in Aix-Marseille-Provence metropolis

The world population is ageing. In France, this phenomenon is particularly pronounced with 19.6% of the population being over 65-year-old in 2018. While it has been recognized that urban form plays an important role in ensuring a sustainable future for urban areas, ageing dynamics are challenging the core concept of urban sustainability. Maintaining or improving the quality of life of an ageing population through urban built form will become as much important, and as much recognized, as ensuring urban environmental sustainability in the future. Today, the well-being of the elderly is still reduced to the economic aspects of the silver economy or to ergonomic aspects in building design. While socio-demographic micro-data on the elderly are available, a comprehensive metropolitan-wide and fine-scale description of the urban forms where seniors live must rely on the latest developments of urban morphometrics. From historic city centres to suburban residential areas, passing through modernist apartment blocks, none of these typical forms seems particularly suited to the needs posed by ageing, which must accommodate accessibility to housing itself and to local shops, health care and services in general. The question of the role of different urban forms over the spatial distribution of the seniors thus arises, as well as the capacity of spatial arrangements to suit the needs and specificities of an ageing population. The case study is a metropolitan area that offers a great heterogeneity of urban forms: Aix- Marseille-Provence, in Southern France. Some areas show over or under-representation of seniors, while others are better at ensuring a generational mix. In most cases, the spatial distribution of the seniors can be linked to specific building hull forms. The spatial distribution of these hull types, and their close relationships to ageing and accessibility are presented in this paper

: Recueil de fiches pédagogiques du réseau MAPS

DoctoralLe réseau thématique MAPS «Modélisation multi-Agent appliquée aux Phénomènes Spatialisés » propose depuis 2009 des évènements scientifiques ayant pour but de diffuser les pratiques de modélisations multi-agents au sein des Sciences de l’Homme et de la Société (SHS). Ce collectif pluridisciplinaire de chercheurs, d’enseignants-chercheurs et de doctorants est labellisé en tant que ≪ réseau thématique » par le Réseau National des Systèmes Complexes (GIS RNSC) et bénéficie du soutien du CNRS au titre de la Formation Permanente. Depuis 2009, plusieurs modèles ont été développés au cours d'événements MAPS. Ces modèles ont fait l'objet de fiches pédagogiques détaillées destinées aux communautés éducatives et universitaires et en particulier aux enseignants qui souhaiteraient faire découvrir la modélisation à leurs étudiants, mais aussi à ceux qui envisagent d’approfondir certains aspects avec un public plus averti. Elles sont également destinées à tous les curieux qui souhaiteraient découvrir ce que la modélisation apporte aux SHS, du point de vue heuristique et du point de vue opérationnel. Enfin, elles sont aussi des supports pour toutes les personnes qui souhaiteraient diffuser les réflexions scientifiques sur la modélisation et la simulation qui ont présidé à la rédaction de ces fiches

Rehabilitation needs for older adults with stroke living at home: perceptions of four populations

<p>Abstract</p> <p>Background</p> <p>Many people who have suffered a stroke require rehabilitation to help them resume their previous activities and roles in their own environment, but only some of them receive inpatient or even outpatient rehabilitation services. Partial and unmet rehabilitation needs may ultimately lead to a loss of functional autonomy, which increases utilization of health services, number of hospitalizations and early institutionalization, leading to a significant psychological and financial burden on the patients, their families and the health care system. The aim of this study was to explore partially met and unmet rehabilitation needs of older adults who had suffered a stroke and who live in the community. The emphasis was put on needs that act as obstacles to social participation in terms of personal factors, environmental factors and life habits, from the point of view of four target populations.</p> <p>Methods</p> <p>Using the focus group technique, we met four types of experts living in three geographic areas of the province of Québec (Canada): older people with stroke, caregivers, health professionals and health care managers, for a total of 12 groups and 72 participants. The audio recordings of the meetings were transcribed and NVivo software was used to manage the data. The process of reducing, categorizing and analyzing the data was conducted using themes from the Disability Creation Process model.</p> <p>Results</p> <p>Rehabilitation needs persist for nine capabilities (e.g. related to behaviour or motor activities), nine factors related to the environment (e.g. type of teaching, adaptation and rehabilitation) and 11 life habits (e.g. nutrition, interpersonal relationships). The caregivers and health professionals identified more unmet needs and insisted on an individualized rehabilitation. Older people with stroke and the health care managers had a more global view of rehabilitation needs and emphasized the availability of resources.</p> <p>Conclusion</p> <p>Better knowledge of partially met or unmet rehabilitation needs expressed by the different types of people involved should lead to increased attention being paid to education for caregivers, orientation of caregivers towards resources in the community, and follow-up of patients' needs in terms of adjustment and rehabilitation, whether for improving their skills or for carrying out their activities of daily living.</p