312 research outputs found
Consistency of the posterior distribution and MLE for piecewise linear regression
We prove the weak consistency of the posterior distribution and that of the
Bayes estimator for a two-phase piecewise linear regression mdoel where the
break-point is unknown. The non-differentiability of the likelihood of the
model with regard to the break- point parameter induces technical difficulties
that we overcome by creating a regularised version of the problem at hand. We
first recover the strong consistency of the quantities of interest for the
regularised version, using results about the MLE, and we then prove that the
regularised version and the original version of the problem share the same
asymptotic properties
On particle filters applied to electricity load forecasting
We are interested in the online prediction of the electricity load, within
the Bayesian framework of dynamic models. We offer a review of sequential Monte
Carlo methods, and provide the calculations needed for the derivation of
so-called particles filters. We also discuss the practical issues arising from
their use, and some of the variants proposed in the literature to deal with
them, giving detailed algorithms whenever possible for an easy implementation.
We propose an additional step to help make basic particle filters more robust
with regard to outlying observations. Finally we use such a particle filter to
estimate a state-space model that includes exogenous variables in order to
forecast the electricity load for the customers of the French electricity
company \'Electricit\'e de France and discuss the various results obtained
Littérature de jeunesse et représentations « genrées » chez les élèves de 6 à 10 ans
De par sa place dans l’univers de l’enfance et de l’éducation, la littérature de jeunesse joue un rôle crucial dans les valeurs et représentations transmises aux enfants. Longtemps accusée de transmettre aux enfants des représentations stéréotypées, elle a évolué au fil du temps. Les albums de jeunesse tendent désormais à se séparer progressivement des stéréotypes à travers l’émergence d’albums contre-stéréotypés. Or, la lecture d’albums contre-stéréotypés influence-t-elle les représentations « genrées » des élèves au sein d’une école qui se base sur le principe d’égalité ? Au travers d’une étude fondée sur deux albums de littérature de jeunesse contre-stéréotypés « fille » (Le meilleur cow-boy de l’Ouest) et « garçon » (Hector, l’homme extraordinairement fort) étudiés dans deux classes de cycles 2 (CP) et 3 (CE2-CM1-CM2), il est apparu que les enfants âgés de 6 à 10 ans avaient une représentation des genres masculin et féminin empreinte de stéréotypes. Suite à la lecture d’albums contre-stéréotypés, les représentations des élèves, et notamment des plus âgés, semblaient avoir évolué vers des représentations non-stéréotypées. Toutefois, cette évolution des représentations est apparue fortement tributaire de l’âge des élèves : la modification des représentations sociales ne semble pas perdurer de la même manière dans le temps suivant la maturité d’identité sexuée et les connaissances qu’ont les élèves sur le monde ; les élèves de cycle 3 étant beaucoup plus réceptifs à la morale véhiculée par les albums que les élèves de cycle 2
Construction of an informative hierarchical prior for a small sample with the help of historical data and application to electricity load forecasting
We are interested in the estimation and prediction of a parametric model on a
short dataset upon which it is expected to overfit and perform badly. To
overcome the lack of data (relatively to the dimension of the model) we propose
the construction of an informative hierarchical Bayesian prior based upon
another longer dataset which is assumed to share some similarities with the
original, short dataset. We illustrate the performance of our prior on
simulated dataset from three standard models. Then we apply the methodology to
a working model for the electricity load forecasting on real datasets, where it
leads to a substantial improvement of the quality of the predictions
Later cART Initiation in Migrant Men from Sub-Saharan Africa without Advanced HIV Disease in France
International audienceObjectiveTo compare the time from entry into care for HIV infection until combination antiretroviral therapy (cART) initiation between migrants and non migrants in France, excluding late access to care.MethodsAntiretroviral-naïve HIV-1-infected individuals newly enrolled in the FHDH cohort between 2002–2010, with CD4 cell counts >200/μL and no previous or current AIDS events were included. In three baseline CD4 cell count strata (200–349, 350-499, ≥500/μL), we examined the crude time until cART initiation within three years after enrolment according to geographic origin, and multivariable hazard ratios according to geographic origin, gender and HIV-transmission group, with adjustment for baseline age, enrolment period, region of care, plasma viral load, and HBV/HBC coinfection.ResultsAmong 13338 individuals, 9605 (72.1%) were French natives (FRA), 2873 (21.4%) were migrants from sub-Saharan Africa/non-French West Indies (SSA/NFW), and 860 (6.5%) were migrants from other countries. Kaplan-Meier probabilities of cART initiation were significantly lower in SSA/NFW than in FRA individuals throughout the study period, regardless of the baseline CD4 stratum. After adjustment, the likelihood of cART initiation was respectively 15% (95%CI, 1–28) and 20% (95%CI, 2–38) lower in SSA/NFW men than in FRA men who had sex with men (MSM) in the 350-499 and ≥500 CD4 strata, while no difference was observed between other migrant groups and FRA MSM.ConclusionSSA/NFW migrant men living in France with CD4 >350/μL at entry into care are more likely to begin cART later than FRA MSM, despite free access to treatment. Administrative delays in obtaining healthcare coverage do not appear to be responsible
Position-referenced microscopy for live cell culture monitoring
Position-referenced microscopy (PRM) is based on smart sample holders that integrate a position reference pattern (PRP) in their depth, allowing the determination of the lateral coordinates with respect to the sample-holder itself. Regions of interest can thus be retrieved easily after culture dish transfers from a cell incubator to the microscope stage. Images recorded at different instants in time are superimposed in a common coordinate system with subpixel accuracy. This paper presents such smart Petri culture dishes and their use for live cell culture monitoring. The impact of the PRP on the light budget is discussed and performances are demonstrated. First results on the application of PRM to the observation of apoptotic body internalization are reported
Classical pathway activity C3c, C4 and C1-inhibitor protein reference intervals determination in EDTA plasma
Introduction: Reference intervals (RIs) for complement assays in EDTA plasma samples have not previously been published. The objectives of the
present study were to validate and/or determine RIs for classical pathway (CP50) activity and C3c, C4 and C1 inhibitor protein (C1INH) assays and to
assess the need for age-specific RIs in EDTA plasma.
Materials and methods: We retrospectively evaluated a cohort of 387 patients attending our university hospital and known to be free of complement-
modifying diseases. The need for age partitioning was assessed and RIs were calculated according to the CLSI protocol.
Results: No need for age partitioning was evidenced for CP50 activity, C3c and C4 concentrations and RIs (90% CI) were calculated from the pooled
data: 35.4 (33.1-37.2) to 76.3 (73.7-83.6) U/mL for CP50 activity, 0.80 (0.75-0.87) to 1.64 (1.59-1.72) g/L for C3c, and 0.12 (0.10-0.14) to 0.38 (0.36-
0.40) g/L for C4. Our results highlight a positive association between age and C1INH concentrations. We derived 3 age partitions (6 months to 30
years, 30-50 and > 50 years) and the related RIs: 0.20 (0.18-0.21) to 0.38 (0.36-0.40) g/L, 0.22 (0.20-0.24) to 0.39 (0.36-0.41) g/L and 0.25 (0.22-0.27)
to 0.41 (0.40-0.43) g/L, respectively).
Conclusions: The newly determined RIs for CP50 activity were higher than those provided by the manufacturer for EDTA plasma samples, whereas
those for C3c and C4 RIs were similar to the values provided for serum samples. The C1INH concentration and activity were found to be associated
with age and age-specific RIs are mandatory for this analyte
French Experience of 2009 A/H1N1v Influenza in Pregnant Women
BACKGROUND: The first reports on the pandemic influenza 2009 A/H1N1v from the USA, Mexico, and Australia indicated that this disease was associated with a high mortality in pregnant women. The aim of this study was to describe and compare the characteristics of severe critically ill and non-severe pregnant women with 2009 A/H1N1v-related illness in France. METHODOLOGY/PRINCIPAL FINDINGS: A national registry was created to screen pregnant women with laboratory-confirmed 2009 A/H1N1v influenza. Three hundred and fifteen patients from 46 French hospitals were included: 40 patients were admitted to intensive care units (severe outcomes), 111 were hospitalized in obstetric or medical wards (moderate outcomes), and 164 were outpatients (mild outcomes). The 2009 A/H1N1v influenza illness occurred during all pregnancy trimesters, but most women (54%), notably the severe patients (70%), were in the third trimester. Among the severe patients, twenty (50%) underwent mechanical ventilation, and eleven (28%) were treated with extracorporeal membrane oxygenation. Three women died from A/H1N1v influenza. We found a strong association between the development of a severe outcome and both co-existing illnesses (adjusted odds ratio [OR], 5.1; 95% confidence interval [CI], 2.2-11.8) and a delay in oseltamivir treatment after the onset of symptoms (>3 or 5 days) (adjusted OR, 4.8; 95% CI, 1.9-12.1 and 61.2, 95% CI; 14.4-261.3, respectively). Among the 140 deliveries after 22 weeks of gestation known to date, 19 neonates (14%) were admitted to a neonatal intensive care unit, mainly for preterm delivery, and two neonates died. None of these neonates developed 2009 A/H1N1v infection. CONCLUSIONS: This series confirms the high incidence of complications in pregnant women infected with pandemic A/H1N1v observed in other countries but depicts a lower overall maternal and neonatal mortality and morbidity than indicated in the USA or Australia. Moreover, our data demonstrate the benefit of early oseltamivir treatment in this specific population
Future development of apricot blossom blight under climate change in Southern France
International audienceClimate change will have several consequences for agro-systems, one of which will concern changes to the development of pathogens. Because of the losses it causes, particularly in organic farming, Monilinia laxa is an important pathogen affecting apricot crops. This study focuses on the consequences of climate change regarding blossom and twig blight (Monilinia laxa) of apricot. To achieve this, a Climatic Index of cumulated Blight risk (CIB) was built, to obtain the weighted sum of blossom blight incidence throughout the blooming period. An epidemiological model to calculate the incidence of blossom blight during every potentially infectious episode and based on biological parameters, was calibrated using a trap pot experiment where trees were placed in orchards and subject to various meteorological conditions. The CIB derived from this model was evaluated on field data, and was shown to be a robust and useful tool to predict the effects of climate change on the development of apricot blight. Then, using the CIB with a phenological model to predict blooming periods in the future, we estimated the risks of apricot blight until 2100 on four contrasted apricot cultivars and in three geographical zones under climate change scenarios RCP 4.5 and 8.5. This study revealed different effects of climate change depending on the cultivar and altitude. Apricot trees would bloom earlier (up to a difference of 50 days between 1950 and 2100) under climate change. Under the combined effects of these shifts of blooming period and changing climatic conditions, late cultivars such as Bergarouge might see a reduction in the risk of blossom blight (down to 31%) because of warmer but dryer blooming periods. Other varieties (e.g.: Bergeron) could experience an increase in this risk by up to 27% with a shift of the blooming period towards rainier conditions at the highest altitudes. The results of this study could be used to anticipate future changes as well as be used at present as a decision-support tool for farmers
Extending the clinical spectrum of X-linked Tonne-Kalscheuer syndrome (TOKAS):new insights from the fetal perspective
INTRODUCTION:Â Tonne-Kalscheuer syndrome (TOKAS) is a recessive X-linked multiple congenital anomaly disorder caused by RLIM variations. Of the 41 patients reported, only 7 antenatal cases were described.METHOD:Â After the antenatal diagnosis of TOKAS by exome analysis in a family followed for over 35 years because of multiple congenital anomalies in five male fetuses, a call for collaboration was made, resulting in a cohort of 11 previously unpublished cases.RESULTS:Â We present a TOKAS antenatal cohort, describing 11 new cases in 6 French families. We report a high frequency of diaphragmatic hernia (9 of 11), differences in sex development (10 of 11) and various visceral malformations. We report some recurrent dysmorphic features, but also pontocerebellar hypoplasia, pre-auricular skin tags and olfactory bulb abnormalities previously unreported in the literature. Although no clear genotype-phenotype correlation has yet emerged, we show that a recurrent p.(Arg611Cys) variant accounts for 66% of fetal TOKAS cases. We also report two new likely pathogenic variants in RLIM, outside of the two previously known mutational hotspots.CONCLUSION:Â Overall, we present the first fetal cohort of TOKAS, describe the clinical features that made it a recognisable syndrome at fetopathological examination, and extend the phenotypical spectrum and the known genotype of this rare disorder.</p
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