Éditeur(s) : HAL CCSD Society for Industrial and Applied Mathematics
Résumé : International audience
We discuss the control of distributed systems with incomplete data following the notion of no-regret control (or, equivalently, Pareto control) used by Lions in [C. R. Acad. Sci. Paris Ser. I Math., 302 (1986), pp. 223-227] and [C. R. Acad. Sci. Paris Ser. I Math., 302 (1992), pp. 1253-1257]. We associate with the no-regret control a sequence of low-regret controls defined by a quadratic perturbation previously used by Nakoulima, Omrane, and Velin in [C. R. Acad. Sci. Paris Ser. I Math., 330 (2000), pp. 801-806]. In the first part, we prove that the perturbed system corresponds to a sequence of standard control problems and converges to the no-regret (or Pareto) control for which we obtain a singular optimality system. We give also some applications. In the second part, we show how the method can be extended to the evolution case. Equations of parabolic type, Petrowsky type, or hyperbolic type are considered.
ISSN: 0363-0129

hal-00764259
https://hal.univ-antilles.fr/hal-00764259
https://hal.univ-antilles.fr/hal-00764259/document
https://hal.univ-antilles.fr/hal-00764259/file/38018.pdf
DOI : 10.1137/S0363012900380188

Éditeur(s) : HAL CCSD EDP Sciences
Résumé : International audience
We show that the so-called low-regret (or least-regret) control by J. L. Lions [8] fits on the control of ill-posed problems. At each time, we give the characterization of the so-called no-regret control by means of singular optimality systems. For the backward heat ill-posed problem, no Slater hypothesis is assumed on the admissible set of controls U ad. This work is two pieces, and two methods are considered : the regularization method and the null-controllability method. For the first method, a zero order corrector is used, while for the second method, the passage to the limit is easy. The results presented here generalize the works in [2, 3] to the no-regret control. Résumé. On montre que le contrôlè a moindres regrets de J. L. Lions [8] est bien adapté pour le contrôle des desprobì emes mal posés. A chaque fois, on donne une caractérisation du contrôle sans regret par le moyen de systèmes d'optimalité singuliers. Pour leprobì eme de chaleur rétrograde mal posé, aucune hypothèse de type Slater sur l'ensemble des contrôles admissibles U ad n'est nécessaire. Ce travail est divisé en deux parties, et deux méthodes sont considérées: la méthode de régularisation et celle de la contrôlabilitécontrôlabilitéà zéro. Pour lapremì ere méthode, un correcteur d'ordre zéro est utilisé, alors que pour la seconde méthode le passagè a la limite est simple. Les résultats présentés ici généralisent les travaux dans [2, 3] au contrôle sans regret.
ISSN: 1270-900X

Droits : info:eu-repo/semantics/OpenAccess
hal-01683792
https://hal.univ-antilles.fr/hal-01683792
https://hal.univ-antilles.fr/hal-01683792/document
https://hal.univ-antilles.fr/hal-01683792/file/proc071705.pdf

Éditeur(s) : HAL CCSD National Institute of Environmental Health Sciences (NIEHS) National Institute of Environmental Health Sciences
Résumé : International audience
Long-term exposure to persistent pollutants with hormonal properties (endocrine-disrupting chemicals, EDCs) may contribute to the risk of prostate cancer (PCa). However, epidemiological evidence remains limited. We investigated the relationship between PCa and plasma concentrations of universally widespread pollutants, in particular p,p'-dichlorodiphenyl dichloroethene (DDE) and the non-dioxin like polychlorinated biphenyl congener 153 (PCB153). We evaluated before treatment 576 men with newly diagnosed PCa and 655 controls in Guadeloupe (French West Indies). Exposure was analyzed according to case-control status. Associations were assessed by unconditional logistic regression analysis, controlling for confounding factors. Missing data were handled by multiple imputation. We estimated a significant positive association between DDE and PCa (adjusted odds ratio [OR] 1.53; 95% CI 1.02, 2.30 for the highest versus lowest quintile of exposure; PTrend = 0.01). PCB153 was inversely associated with PCa (OR 0.30; 95% CI 0.19, 0.47 for the highest versus lowest quintile of exposure values; PTrend < 0.001). Also, PCB153 was more strongly associated to low-grade than high grade PCa. Associations of PCa with DDE and PCB153 were in opposite directions. This may reflect differences in the mechanisms of action of these EDCs, and although our findings need to be replicated in other populations, they are consistent with complex effects of EDCs on human health.
ISSN: 0091-6765

hal-01118553
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01118553
DOI : 10.1289/ehp.1408407
PUBMED : 25493337

Éditeur(s) : HAL CCSD EDP Sciences
Résumé : International audience
We show that the so-called low-regret (or least-regret) control by J. L. Lions [8] fits on the control of ill-posed problems. At each time, we give the characterization of the so-called no-regret control by means of singular optimality systems. For the backward heat ill-posed problem, no Slater hypothesis is assumed on the admissible set of controls ${{cal U}_{mbox{ iny ad}}}$. This work is two pieces, and two methods are considered : the regularization method and the null-controllability method. For the first method, a zero order corrector is used, while for the second method, the passage to the limit is easy. The results presented here generalize the works in [2,3] to the no-regret control.
ISSN: 1270-900X

hal-00720814
https://hal.univ-antilles.fr/hal-00720814
https://hal.univ-antilles.fr/hal-00720814/document
https://hal.univ-antilles.fr/hal-00720814/file/esaimpr1.pdf

Éditeur(s) : HAL CCSD
Résumé : poster presentation, 22nd European Meeting on Hypertension and Cardiovascular protection, London,26-29 April 2012
OBJECTIVE: Several studies demonstrate that the perception of overweight is associated with attempts at weight control in overweight subjects. Our objective is to describe the factors associated with the perception of overweight in an adult Caribbean population, and in particular, to assess the relationship between the perception of overweight and previous medical diagnosis of overweight. METHOD AND DESIGN: Consant was a cross-sectional study carried out in 2007 on a representative sample of the adult Guadeloupean population. Included were 1,005 subjects aged 25-74 years, drawn from stratified random sampling, and interviewed at home. The perception of overweight was evaluated by the question: "Do you consider yourself to be overweight?" with a binary response. RESULTS: Among overweight subjects (Body Mass Index ≥ 25 kg/m2, n = 576), 38.6% provided an incorrect assessment of their weight status. This proportion falls to 17.4% in those who stated to have previously received a medical diagnosis of overweight. However, only 48.8% of overweight subjects stated to have received such a diagnosis. A logistic regression shows that the underestimation of weight status is associated with the absence of previous diagnosis for overweight (OR: 5.35 - p < 10-3), as well as an age greater than or equal to 55 years (OR: 2.91 - p < 10-3), a BMI of less than 30 kg/m² (OR: 2.26 - p: 0.001), the male sex (OR: 1.86 - p: 0.004), and a low income level (OR: 1.62 - p: 0.030), but not a lack of awareness regarding the role of weight control in the prevention of cardiovascular diseases. Similar results are observed if waist circumference is taken as a factor instead of BMI. CONCLUSION: In this population, the lack of medical diagnosis of overweight was the leading factor associated with misperception of overweight. Screening for overweight therefore appears to be one of the preconditions to weight management, and remains a fundamental but often unused element in the fight against obesity.
https://hal.univ-antilles.fr/hal-00739785

Droits : info:eu-repo/semantics/OpenAccess
hal-00739785
https://hal.univ-antilles.fr/hal-00739785
https://hal.univ-antilles.fr/hal-00739785/document
https://hal.univ-antilles.fr/hal-00739785/file/The_lacksur screening_is_the_leading_factor_associated_with_the_misperceptionsur overweight_cor.pdf

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
We use the low-regret notion of Lions for the control of a class of singular distributed systems: the ill-posed problems. A regularization approach is applied to the backwards heat equation, and we obtain a problem of incomplete data, for which the method of Nakoulima et al. is developed. Passing to the limit, a singular optimality system is obtained for the low-regret control of the original problem without any Slater hypothesis.
ISSN: 0893-9659

hal-00763938
https://hal.univ-antilles.fr/hal-00763938
DOI : 10.1016/j.aml.2003.04.006

Éditeur(s) : Elsevier
Résumé : Emplacement of post-glacial turbidites is commonly controlled by rapid changes in sea level or by seismicity. On the continental rise of the Gulf of Lions (Western Mediterranean), an aseismic area, we identified turbiditic beds deposited during the rising stage and highstand of sea level. Swath bathymetry, sediment cores, in situ Cone Penetrating Tests (CPTU), heavy mineral associations and radiocarbon dating determined the source, composition, distribution and age of the turbiditic beds. Turbidites are composed of homogeneous to positively graded silts to medium sand with quartz (up to 90%), shell debris and shelfal benthic faunas. Their distribution on the sea floor is very patchy and controlled by abundant inherited erosional bedforms. Their source is found in relict regressive sands at the outershelf. Their deposition occurred just after the onset of the post-glacial sea level rise and the concomitant sediment starvation of the Rhone deep sea turbiditic system until recently. Whilst canyons are fed with sand by strong seasonal hydro-sedimentary dynamics on the outershelf, the emplacement of post-glacial turbidites is not controlled by sea level changes but probably by the periodic flushing of the canyons. Our study revealed that this low energy aseismic margin undergoes significant transport of sand, down to the base of slope, during the sea-level rise and the Holocene highstand.
Marine Geology (0025-3227) (Elsevier), 2009-02 , Vol. 257 , N. 1-4 , P. 65-86

Droits : 2009 Published by Elsevier Ltd.
http://archimer.ifremer.fr/doc/2009/publication-6316.pdf
DOI:10.1016/j.margeo.2008.10.013
http://archimer.ifremer.fr/doc/00000/6316/

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
BACKGROUND: Estrogens are thought to play a critical role in prostate carcinogenesis. It has been suggested that polymorphisms of genes encoding enzymes involved in estrogen metabolism are risk factors for prostate cancer. However, few studies have been performed on populations of African ancestry, which are known to have a high risk of prostate cancer. OBJECTIVE: We investigated whether functional polymorphisms of CYP17, CYP19, CYP1B1, COMT and UGT1A1 affected the risk of prostate cancer in two different populations of African ancestry. METHODS: In Guadeloupe (French West Indies), we compared 498 prostate cancer patients and 565 control subjects. In Kinshasa (Democratic Republic of Congo), 162 prostate cancer patients were compared with 144 controls. Gene polymorphisms were determined by the SNaPshot technique or short tandem repeat PCR analysis. Logistic regression was used to estimate adjusted odds ratios (OR) and 95% confidence intervals (CI). RESULTS: The AA genotype and the A allele of rs4680 (COMT) appeared to be inversely associated with the risk of prostate cancer in adjusted models for both Afro-Caribbean and native African men. For the A allele, a significant inverse association was observed among cases with low-grade Gleason scores and localized clinical stage, in both populations. CONCLUSIONS: These preliminary results support the hypothesis that polymorphisms of genes encoding enzymes involved in estrogen metabolism may modulate the risk of prostate cancer in populations of African ancestry
ISSN: 1932-6203

hal-01305477
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01305477
DOI : 10.1371/journal.pone.0153609
PUBMED : 27074016

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
BACKGROUND: Estrogens are thought to play a critical role in prostate carcinogenesis. It has been suggested that polymorphisms of genes encoding enzymes involved in estrogen metabolism are risk factors for prostate cancer. However, few studies have been performed on populations of African ancestry, which are known to have a high risk of prostate cancer.OBJECTIVE: We investigated whether functional polymorphisms of CYP17, CYP19, CYP1B1, COMT and UGT1A1 affected the risk of prostate cancer in two different populations of African ancestry.METHODS: In Guadeloupe (French West Indies), we compared 498 prostate cancer patients and 565 control subjects. In Kinshasa (Democratic Republic of Congo), 162 prostate cancer patients were compared with 144 controls. Gene polymorphisms were determined by the SNaPshot technique or short tandem repeat PCR analysis. Logistic regression was used to estimate adjusted odds ratios (OR) and 95% confidence intervals (CI).RESULTS: The AA genotype and the A allele of rs4680 (COMT) appeared to be inversely associated with the risk of prostate cancer in adjusted models for both Afro-Caribbean and native African men. For the A allele, a significant inverse association was observed among cases with low-grade Gleason scores and localized clinical stage, in both populations.CONCLUSIONS: These preliminary results support the hypothesis that polymorphisms of genes encoding enzymes involved in estrogen metabolism may modulate the risk of prostate cancer in populations of African ancestry.
ISSN: 1932-6203

hal-01668333
https://hal.univ-antilles.fr/hal-01668333
DOI : 10.1371/journal.pone.0153609
PUBMED : 27074016

Éditeur(s) : HAL CCSD
Résumé : International audience
To study the associations between occupation, industry and prostate cancer risk in Guadeloupe, a high incidence area. Incident cases of prostate cancer (707 cases) and 722 population controls were included. Information on lifetime occupational history and other potential risk factors was collected by interview. Logistic regression was used to estimate adjusted odds-ratios (OR) and their 95% confidence intervals (CI). A significantly decreased risk was observed in farmers (OR=0.5; CI 0.4-0.7), whereas marginally elevated ORs were found for farm workers, especially in sugarcane and banana farming. Banana plantation workers had been exposed to chlordecone, an estrogenic insecticide previously found to be associated with prostate cancer risk in this population. Significantly increased risks of prostate cancer were found in stock clerks (OR=2.7; CI 1.0-7.2), fishermen (OR=2.0; CI 1.0-4.0), mail distribution clerks (OR=7.7; CI 1.7-34.4) and electricians employed for more than 20 years (OR=4.0; CI 1.0-15.8), as well as in public administration (OR=1.8; CI 1.2-2.9), retail trade (OR=2.6; CI 1.1-6.0) and manufacture of food products (OR=2.0; CI 1.1-3.9), particularly sugar (OR=13.2; IC 1.6-108). Non-significantly elevated ORs were also seen for construction workers and transport equipment operators. Although the overall findings suggest that occupational factors have only a limited role in prostate cancer aetiology, elevated risks of prostate cancer were found in several occupations or industries. Exposure to pesticides, solvents, traffic-related air pollution, low physical activity, whole-body vibration may explain some of these increased risks.
Challenges for Occupational Epidemiology in the 21st Century EPICOH 2014
Chicago, United States

hal-01118558
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01118558
DOI : 10.1136/oemed-2014-102362.312
PUBMED : 25018167