67 research outputs found
Occupational Health Problem Network : the Exposome
We present a thinking on the concept of relational networks applied to the
french national occupational disease surveillance and prevention network
(R\'eseau National de Vigilance et de Pr\'evention des Pathologies
Professionnelles, RNV3P). This approach consists in searching common exposures
to occupational health problems
Size-independence of statistics for boundary collisions of random walks and its implications for spin-polarized gases
A bounded random walk exhibits strong correlations between collisions with a
boundary. For an one-dimensional walk, we obtain the full statistical
distribution of the number of such collisions in a time t. In the large t
limit, the fluctuations in the number of collisions are found to be
size-independent (independent of the distance between boundaries). This occurs
for any inter-boundary distance, including less and greater than the
mean-free-path, and means that this boundary effect does not decay with
increasing system-size. As an application, we consider spin-polarized gases,
such as 3-Helium, in the three-dimensional diffusive regime. The above results
mean that the depolarizing effect of rare magnetic-impurities in the container
walls is orders of magnitude larger than a Smoluchowski assumption (to neglect
correlations) would imply. This could explain why depolarization is so
sensitive to the container's treatment with magnetic fields prior to its use.Comment: 5 page manuscript with extra details in appendices (additional 3
pages
A network-based approach for surveillance of occupational health exposures
In the context of surveillance of health problems, the research carried out
by the French national occupational disease surveillance and prevention network
(R\'eseau National de Vigilance et de Pr\'evention des Pathologies
Professionnelles, RNV3P) aims to develop, among other approaches, methods of
surveillance, statistical analysis and modeling in order to study the structure
and change over time of relationships between disease and exposure, and to
detect emerging disease-exposure associations. In this perspective, this paper
aims to present the concept of the "exposome" and to explain on what bases it
is constructed. The exposome is defined as a network of relationships between
occupational health problems that have in common one or several elements of
occupational exposure (exposures, occupation and/or activity sector). The paper
also aims to outline its potential for the study and programmed surveillance of
composite disease-occupational exposure associations. We illustrate this
approach by applying it to a sample from the RNV3P data, taking malignant
tumours and focusing on the subgroup of non-Hodgkin lymphomas
Simulation of a semiflexible polymer in a narrow cylindrical pore
The probability that a randomly accelerated particle in two dimensions has
not yet left a simply connected domain after a time decays as
for long times. The same quantity also determines the
confinement free energy per unit length of a
semiflexible polymer in a narrow cylindrical pore with cross section . From simulations of a randomly accelerated particle we estimate the
universal amplitude of for both circular and rectangular cross
sections.Comment: 10 pages, 2 eps figure
Bird species involved in west nile virus epidemiological cycle in southern Québec
Despite many studies on West Nile Virus (WNV) in the US, including the reservoir role of
bird species and the summer shifts of the Culex mosquito, feeding from birds to mammals, there have
been few equivalent studies in the neighboring regions of Canada where WNV is endemic. Here,
a priority list of bird species likely involved in WNV transmission in the greater Montréal area is
constructed by combining three sources of data: (i) from WNV surveillance in wild birds (2002–2015);
(ii) blood meal analysis of Culex pipiens–restuans (CPR), the primary enzootic vectors of WNV in the
region, collected from surveillance in 2008 and 2014; (iii) literature review on the sero-prevalence/host
competence of resident birds. Each of these data sources yielded 18, 23 and 53 species, and overall,
67 different bird species were identified as potential WNV amplifiers/reservoirs. Of those identified
from CPR blood meals, Common starlings, American robins, Song sparrows and House sparrows
ranked the highest and blood meal analysis demonstrated a seasonal shift in feed preference from
birds to mammals by CPR. Our study indicates that there are broad similarities in the ecology of
WNV between our region and the northeastern US, although the relative importance of bird species
varies somewhat between regions
Model to Track Wild Birds for Avian Influenza by Means of Population Dynamics and Surveillance Information
Design, sampling and data interpretation constitute an important challenge for wildlife surveillance of avian influenza
viruses (AIV). The aim of this study was to construct a model to improve and enhance identification in both different periods
and locations of avian species likely at high risk of contact with AIV in a specific wetland. This study presents an individualbased
stochastic model for the Ebre Delta as an example of this appliance. Based on the Monte-Carlo method, the model
simulates the dynamics of the spread of AIV among wild birds in a natural park following introduction of an infected bird.
Data on wild bird species population, apparent AIV prevalence recorded in wild birds during the period of study, and
ecological information on factors such as behaviour, contact rates or patterns of movements of waterfowl were
incorporated as inputs of the model. From these inputs, the model predicted those species that would introduce most of
AIV in different periods and those species and areas that would be at high risk as a consequence of the spread of these AIV
incursions. This method can serve as a complementary tool to previous studies to optimize the allocation of the limited AI
surveillance resources in a local complex ecosystem. However, this study indicates that in order to predict the evolution of
the spread of AIV at the local scale, there is a need for further research on the identification of host factors involved in the
interspecies transmission of AI
Bayesian mapping of pulmonary tuberculosis in Antananarivo, Madagascar
<p>Abstract</p> <p>Background</p> <p>Tuberculosis (TB), an infectious disease caused by the <it>Mycobacterium tuberculosis </it>is endemic in Madagascar. The capital, Antananarivo is the most seriously affected area. TB had a non-random spatial distribution in this setting, with clustering in the poorer areas. The aim of this study was to explore this pattern further by a Bayesian approach, and to measure the associations between the spatial variation of TB risk and national control program indicators for all neighbourhoods.</p> <p>Methods</p> <p>Combination of a Bayesian approach and a generalized linear mixed model (GLMM) was developed to produce smooth risk maps of TB and to model relationships between TB new cases and national TB control program indicators. The TB new cases were collected from records of the 16 Tuberculosis Diagnostic and Treatment Centres (DTC) of the city from 2004 to 2006. And five TB indicators were considered in the analysis: number of cases undergoing retreatment, number of patients with treatment failure and those suffering relapse after the completion of treatment, number of households with more than one case, number of patients lost to follow-up, and proximity to a DTC.</p> <p>Results</p> <p>In Antananarivo, 43.23% of the neighbourhoods had a standardized incidence ratio (SIR) above 1, of which 19.28% with a TB risk significantly higher than the average. Identified high TB risk areas were clustered and the distribution of TB was found to be associated mainly with the number of patients lost to follow-up (SIR: 1.10, CI 95%: 1.02-1.19) and the number of households with more than one case (SIR: 1.13, CI 95%: 1.03-1.24).</p> <p>Conclusion</p> <p>The spatial pattern of TB in Antananarivo and the contribution of national control program indicators to this pattern highlight the importance of the data recorded in the TB registry and the use of spatial approaches for assessing the epidemiological situation for TB. Including these variables into the model increases the reproducibility, as these data are already available for individual DTCs. These findings may also be useful for guiding decisions related to disease control strategies.</p
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