Estimating the basic reproduction number from noisy daily data.

In this paper, we propose an easy to implement generalized linear models (GLM) methodology for estimating the basic reproduction number, R, a major epidemic parameter for assessing the transmissibility of an infection. Our approach rests on well known qualitative properties of the classical SIR and SEIR systems for large populations. Moreover, we assume that information at the individual network level is not available.

A statistical tool for comparing seasonal ILI surveillance data.

In this paper, we consider the yearly influenza epidemic, as reflected in the seasonal surveillance data compiled by the CDC (Center for Disease Control and Prevention, USA) and we explore a new methodology for comparing specific features of these data. In particular, we focus on the ten HHS (Health and Human Services) regions, and how the incidence data evolves in these regions. In order to perform the comparisons, we consider the relative distribution of weekly new cases over one season and replace the crude data with predicted values.

Inferring the demographic history from DNA sequences: An importance sampling approach based on non-homogeneous processes.

In Ait Kaci Azzou et al. (2015) we introduced an Importance Sampling (IS) approach for estimating the demographic history of a sample of DNA sequences, the skywis plot. More precisely, we proposed a new nonparametric estimate of a population size that changes over time.

A new method for estimating the demographic history from DNA sequences: an importance sampling approach.

The effective population size over time (demographic history) can be retraced from a sample of contemporary DNA sequences. In this paper, we propose a novel methodology based on importance sampling (IS) for exploring such demographic histories. Our starting point is the generalized skyline plot with the main difference being that our procedure, skywis plot, uses a large number of genealogies.

Estimating the basic reproduction number from surveillance data on past epidemics.

In this paper, we consider the basic reproduction number, R0, a parameter that characterizes the transmission potential of an epidemic, and explore a novel way for estimating it. We introduce a stochastic process which takes as starting points the classical SIR (susceptibles-infected-removed) models, deterministic and stochastic. The estimation method rests on an extremum property of the deterministic SIR model, and could be applied to past surveillance data on epidemic outbreaks, data gathered at different locations or in different years.

Prediction of predator-prey populations modelled by perturbed ODEs.

In this paper we explore a stochastic model in continuous time for predator-prey interactions, which accounts for the periodical behaviour observed in many animal populations. More precisely, we consider a solution to the classical Lotka-Volterra system of equations, but we view the actual population sizes as random perturbations of the solutions to this ODE system. Namely, we assume that the perturbations follow correlated Ornstein-Uhlenbeck processes; this approach generalizes the one of Froda and Colavita [Aust N Z J Stat 2:235-254, 2005] who considered only i.

Canadian projections of cases suffering from Alzheimer's disease and senile dementia of Alzheimer type over the period 1986-2031.

Alzheimer's disease (AD) is characterized by irreversible changes in cognitive and intellectual functions, accompanied by progressive memory loss, and described by neurochemical and neuropathological impairments. The classic term Alzheimer's disease applies to presenile dementia, while all of the syndromes that share the distinctive signs of AD are known as senile dementia of the Alzheimer type (SDAT). In Canada, as in several other industrialized countries, we are seeing a rapid growth of the elderly population.

Parental age and birth order in Alzheimer's disease: a case-control study in the Saguenay-Lac-St-Jean area (Quebec, Canada).

Parental age at the time of birth of 133 clinically diagnosed Alzheimer patients from the Saguenay-Lac-St-Jean area (Quebec, Canada) were compared with those of 6 control groups formed out a population registry. The birth order of the Alzheimer patients was also analyzed. The results did not show any parental age or birth order effect, which is in agreement with previous reports.

The reliability of the maternal memory in a retrospective assessment of nutritional status.

This study raises the question of the validity of conclusions based on recalled data by testing the maternal ability to report vital events on her newborn infant after 8 years. First, the retrospective information given by the mother was compared to the prospective data collected immediately after birth. Second, the validity of statistical analyses based on retrospective data was discussed.