22,908 research outputs found
Semi-parametric estimation of the hazard function in a model with covariate measurement error
We consider a model where the failure hazard function, conditional on a
covariate is given by ,
with . The baseline
hazard function and relative risk belong both
to parametric families. The covariate is measured through the error model
where is independent from , with known density
. We observe a -sample , , where
is the minimum between the failure time and the censoring time, and
is the censoring indicator. We aim at estimating in presence
of the unknown density . Our estimation procedure based on least squares
criterion provide two estimators. The first one minimizes an estimation of the
least squares criterion where is estimated by density deconvolution. Its
rate depends on the smoothnesses of and as a
function of ,. We derive sufficient conditions that ensure the
-consistency. The second estimator is constructed under conditions
ensuring that the least squares criterion can be directly estimated with the
parametric rate. These estimators, deeply studied through examples are in
particular -consistent and asymptotically Gaussian in the Cox model
and in the excess risk model, whatever is
Individual and Collective Resources and Health in Morocco
The interaction between available individual and collective resources in the determination of health is largely ignored in the literature on the relationship between poverty and health in developing countries. We analyse the role public resources play in the perception that rural women in Morocco have of their health. These resources are taken to contribute directly and indirectly to the improvement of individual health by, on the one hand, providing a health-promoting environment and, on the other, improving the individual?s ability to produce health. The empirical results of multilevel models confirm the expected associations between socioeconomic status, individual vulnerability factors and health. Furthermore, the random part of the model suggests that variation in state of health is also associated with the presence of collective resources. However, the higher the level of women?s individual wealth, the less the characteristics of the community in which they live seem to be associated with their health, and the less the potential vulnerability factors seem to constrain their ability to maintain or improve health. Our results suggest that collective investments derived from various areas of activity will be more favourable to improving health, insofar as they are adapted to the initial capacity of women to benefit from them.health, poverty, rural, women, Morocco
On a Boltzmann mean field model for knowledge growth
In this paper we analyze a Boltzmann type mean field game model for knowledge
growth, which was proposed by Lucas and Moll. We discuss the underlying
mathematical model, which consists of a coupled system of a Boltzmann type
equation for the agent density and a Hamilton-Jacobi-Bellman equation for the
optimal strategy. We study the analytic features of each equation separately
and show local in time existence and uniqueness for the fully coupled system.
Furthermore we focus on the construction and existence of special solutions,
which relate to exponential growth in time - so called balanced growth path
solutions. Finally we illustrate the behavior of solutions for the full system
and the balanced growth path equations with numerical simulations.Comment: 6 figure
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