Éditeur(s) : HAL CCSD IGI Global
Résumé : International audience
The social behavior of individuals is an important factor of the transmission and the evolution of many diseases. As such, epidemic studies have attempted to integrate social aspects in dissemination modeling. Since the pioneering works of Klovdahl on AIDS in 1985, epidemiological investigations and interventions increasingly focus on social networks. Significant factors of the transmission and outbreak of many infectious diseases are the structure and nature of human interactions. Network-based modeling approaches have found various applications in epidemiology as a simple yet efficient way to represent the complexity of human relationships implicated in dissemination processes. However, most results have been obtained by considering social networks as steady stage structures. Evolving networks have not been explored. The objective is first to give an overview of network-based modeling attempts in epidemiology to analyze and understand the dissemination processes with an emphasis on dynamic networks. The authors approach is designed to understand the impact of social links dynamics on epidemic spread. The authors present the results obtained by combining network evolution patterns (link creation and deletion) and a typical epidemic model. The speed of link dynamics and the infection time strongly influence the occurrence and value of the epidemic peak.
ISSN: 1947-8186

hal-00700105
https://hal.archives-ouvertes.fr/hal-00700105
DOI : 10.4018/jismd.2012070103

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
Hydroxycarbamide (HC) treatment has been shown to improve the clinical course of patients with sickle cell anaemia (SCA), a haemoglobinopathy resulting from a single base substitution in the bêta-globin gene (HBB). SCA is characterized by chronic haemolytic anaemia and recurrent vascular occlusions leading to multisystemic complications. Several beneficial biological effects of HC have been documented (Halsey et al, 2003) but its impact on the concentration of circulating microparticles (MPs), a subtype of extracellular vesicles released from cytoplasmic membrane of activated or apoptotic cells and detected at high levels in sickle plasma, remains controversial (Hebbel et al, 2016). The aim of the present study was to compare the MP pattern in a group of SCA patients treated by HC and followed for 2 years.
ISSN: 0007-1048

hal-01668320
https://hal.univ-antilles.fr/hal-01668320
https://hal.univ-antilles.fr/hal-01668320/document
https://hal.univ-antilles.fr/hal-01668320/file/Garnier%20et%20al%20BJH-2017-00655.pdf
DOI : 10.1111/bjh.14810

Éditeur(s) : HAL CCSD
Résumé : International audience
BACKGROUND: Africa faces a number of unique environmental challenges. Unfortunately, it lacks the infrastructure needed to support the comprehensive environmental studies that could provide the scientific basis to inform environmental policies. There are a number of known sources of endocrine-disrupting chemicals (EDCs) and other hazardous chemicals in Africa. However, a coordinated approach to identify and monitor these contaminants and to develop strategies for public health interventions has not yet been made. OBJECTIVES: This commentary summarizes the scientific evidence presented by experts at the First African Endocrine Disruptors meeting. We describe a "call to action" to utilize the available scientific knowledge to address the impact of EDCs on human and wildlife health in Africa. DISCUSSION: We identify existing knowledge gaps about exposures to EDCs in Africa and describe how well-designed research strategies are needed to address these gaps. A lack of resources for research and a lag in policy implementation slows down intervention strategies and poses a challenge to advancing future health in Africa. CONCLUSION: To address the many challenges posed by EDCs, we argue that Africans should take the lead in prioritization and evaluation of environmental hazards, including EDCs. We recommend the institution of education and training programs for chemical users, adoption of the precautionary principle, establishment of biomonitoring programs, and funding of community-based epidemiology and wildlife research programs led and funded by African institutes and private companies. https://doi.org/10.1289/EHP1774.
Environmental Health Perspectives

hal-01616487
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01616487
DOI : 10.1289/EHP1774
PUBMED : 28935616

Éditeur(s) : HAL CCSD
Résumé : International audience
Background: Sleep disturbances are one of the main complaints of patients with trauma-related disorders. The original Pittsburgh Sleep Quality Index Addendum for PTSD (PSQI-A) is self-report instrument developed to evaluate posttraumatic stress disorder (PTSD)-specific sleep disturbances in trauma-exposed individuals. However, to date, the PSQI-A has not yet been translated nor validated in French.Objective: The present study aims to: a) translate the PSQI-A into French, and b) examine its psychometric properties.Method: Seventy-three adult patients (mean age=40.3 [SD=15.0], 75% females) evaluated in a specialized psychotraumatology unit completed the French versions of the PSQI-A, Pittsburgh Sleep Quality Index (PSQI), Hospital Anxiety and Depression Scale (HADS), and Impact Event Scale-Revised (IES-R).Results: The French version of the PSQI-A showed satisfactory internal consistency, inter-item correlations, item correlations with the total score, convergent validity with PTSD and anxiety measures, and divergent validity with a depression measure.Conclusion: Our findings support the use of the French version of the PSQI-A for both clinical care and research. The French version of the PSQI-A is an important addition to the currently available instruments that can be used to examine trauma-related sleep disturbances among French-speaking individuals.
ISSN: 2000-8066

Droits : info:eu-repo/semantics/OpenAccess
hal-01532051
http://hal.upmc.fr/hal-01532051
http://hal.upmc.fr/hal-01532051/document
http://hal.upmc.fr/hal-01532051/file/02_06_2017_Validation.pdf
DOI : 10.3402/ejpt.v4i0.19298

Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé : 1. This study focuses on the importance in hyperdiverse regions, such as the Amazonian forest, of accelerating and optimising the census of invertebrate communities.2. We carried out low-intensity sampling of tropical moth (Lepidoptera) assemblages in disturbed forest fragments in Brazil.3. We combined DNA barcoding and taxonomists' expertise to produce fast and accurate surveys of local diversity, including the recognition and census of undescribed and endemic species.4. Integrating expert knowledge of species distributions, we show that despite limited sampling effort, our approach revealed an unexpectedly high number of new and endemic species in severely threatened tropical forest fragments.5. These results highlight the risk of silent centinelan extinctions and emphasise the urgent need for accelerated invertebrate surveys in high-endemism and human-impacted tropical forests.
EISSN: 1752-458X

hal-01602363
https://hal.archives-ouvertes.fr/hal-01602363
DOI : 10.1111/icad.12187
PRODINRA : 389851

Éditeur(s) : HAL CCSD Elsevier Science
Résumé : International audience
Some anthropogenic noise is now considered pollution, with evidence building that noise from human activities such as transportation, construction and exploration can impact behaviour and physiology in a broad range of taxa. However, relatively little research has considered the effects of repeated or chronic noise; extended exposures may result in habituation or sensitisation, and thus changes in response. We conducted a field-based experiment at Moorea Island to investigate how repeated exposure to playback of motorboat noise affected a coral reef fish (Dascyllus trimaculatus). We found that juvenile D. trimaculatus increased hiding behaviour during motorboat noise after two days of repeated exposure, but no longer did so after one and two weeks of exposure. We also found that naïve individuals responded to playback of motorboat noise with elevated ventilation rates, but that this response was diminished after one and two weeks of repeated exposure. We found no strong evidence that baseline blood cortisol levels, growth or body condition were affected by three weeks of repeated motorboat-noise playback. Our study reveals the importance of considering how tolerance levels may change over time, rather than simply extrapolating from results of short-term studies, if we are to make decisions about regulation and mitigation.
ISSN: 0013-9327

Droits : http://creativecommons.org/licenses/by/
hal-01357915
https://hal-univ-perp.archives-ouvertes.fr/hal-01357915
https://hal-univ-perp.archives-ouvertes.fr/hal-01357915/document
https://hal-univ-perp.archives-ouvertes.fr/hal-01357915/file/1-s2.0-S0269749116304468-main.pdf
DOI : 10.1016/j.envpol.2016.05.058

Éditeur(s) : HAL CCSD Endocrine Society
Résumé : International audience
The Developmental Origins of Health and Disease (DOHaD) paradigm is one of the most rapidly expanding areas of biomedical research. Environmental stressors that can impact on DOHaD encompass a variety of environmental and occupational hazards as well as deficiency and oversupply of nutrients and energy. They can disrupt early developmental processes and lead to increased susceptibility to disease/dysfunctions later in life. Presentations at the fourth Conference on Prenatal Programming and Toxicity in Boston, in October 2014, provided important insights and led to new recommendations for research and public health action. The conference highlighted vulnerable exposure windows that can occur as early as the preconception period and epigenetics as a major mechanism than can lead to disadvantageous "reprogramming" of the genome, thereby potentially resulting in transgenerational effects. Stem cells can also be targets of environmental stressors, thus paving another way for effects that may last a lifetime. Current testing paradigms do not allow proper characterization of risk factors and their interactions. Thus, relevant exposure levels and combinations for testing must be identified from human exposure situations and outcome assessments. Testing of potential underpinning mechanisms and biomarker development require laboratory animal models and in vitro approaches. Only few large-scale birth cohorts exist, and collaboration between birth cohorts on a global scale should be facilitated. DOHaD-based research has a crucial role in establishing factors leading to detrimental outcomes and developing early preventative/remediation strategies to combat these risks
ISSN: 0013-7227

hal-01187409
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01187409
DOI : 10.1210/EN.2015-1350
PUBMED : 26241067

Résumé : Les études écologiques sont maintenant considérées comme prometteuses en raison de leur capacité à intégrer dans un même modèle autant des facteurs individuels que populationnels. Le mouvement récent de l’open data pourrait jouer un rôle important dans la pérennisation des démarches multidisciplinaires. Cette thèse montre que l’association des méthodes écologiques aux données publiques permet d’éclairer sous un angle nouveau des problématiques des maladies infectieuses.En Guyane Française, des méthodes écologiques dites de séries temporelles couplées aux données climatiques libres ont contribué à une meilleure compréhension du rôle du climat sur la dynamique de la transmission du paludisme, de la leishmaniose cutanée ainsi que de l’histoplasmose disséminée. L’utilisation de méthodes écologiques sur des données libres de la littérature scientifique concernant la séroprévalence toxoplasmose dans les populations humaines a permis d’identifier les principaux facteurs influençant le niveau de séroprévalence globale et indirectement du risque de toxoplasmose congénital associé. L’association de données onusiennes à des méthodes écologiques a permis de montrer qu’une prévalence importante d’ascaridiose est associée à une réduction par 10 de l’incidence du paludisme et l’impact significatif de la corruption sur la mortalité juvéno-infantile et sur les résistances aux anti-tuberculeux. Ces études montrent que l’association des méthodes écologiques aux données publiques permet d’éclairer sous un angle nouveau des problématiques des maladies infectieuses. Ce type d‘étude fournit la flexibilité nécessaire à l’étude des interactions complexes des nombreux déterminants de la santé.
Ecological studies are now considered promising because of their ability to integrate as well as individual factors than populational ones in the same model. The recent open data movement could play an important role in the sustainability of multidisciplinary approaches. The studies developed in this thesis show that the combination of ecological methods with open data could give original results in the issues of infectious diseases.In French Guiana, ecological methods called time series, coupled with open climate data, have contributed to a better understanding of the role of climate on the dynamics of malaria, cutaneous leishmaniasis and disseminated histoplasmosis. The use of ecological methods with open data from the scientific literature concerning toxoplasmosis seroprevalence in human populations has permitted to identify the main factors influencing the level of overall seroprevalence and indirectly to estimate the associated risk of congenital toxoplasmosis.The combination of UN data to ecological methods has shown that a high prevalence of ascariasis is associated with a reduction from 10 in the incidence of malaria and that corruption has a significant impact on child mortality and resistance to TB.The various studies developed in this thesis show that the combination of ecological methods to public data sheds a new light on the issues of infectious diseases. This type of study provides the flexibility to study the complex interactions of many determinants of health.

http://www.theses.fr/2011AGUY0482/document

Éditeur(s) : HAL CCSD Nature Publishing Group
Résumé : International audience
The etiology of congenital heart defect (CHD) combines environmental and genetic factors. So far, there were studies reporting on the screening of a single gene on unselected CHD or on familial cases selected for specific CHD types. Our goal was to systematically screen a proband of familial cases of CHD on a set of genetic tests to evaluate the prevalence of disease-causing variant identification. A systematic screening of GATA4, NKX2-5, ZIC3 and Multiplex ligation-dependent probe amplification (MLPA) P311 Kit was setup on the proband of 154 families with at least two cases of non-syndromic CHD. Additionally, ELN screening was performed on families with supravalvular arterial stenosis. Twenty-two variants were found, but segregation analysis confirmed unambiguously the causality of 16 variants: GATA4 (1 x), NKX2-5 (6 x), ZIC3 (3 x), MLPA (2 x) and ELN (4 x). Therefore, this approach was able to identify the causal variant in 10.4% of familial CHD cases. This study demonstrated the existence of a de novo variant even in familial CHD cases and the impact of CHD variants on adult cardiac condition even in the absence of CHD. This study showed that the systematic screening of genetic factors is useful in familial CHD cases with up to 10.4% elucidated cases. When successful, it drastically improved genetic counseling by discovering unaffected variant carriers who are at risk of transmitting their variant and are also exposed to develop cardiac complications during adulthood thus prompting long-term cardiac follow-up. This study provides an important baseline at dawning of the next-generation sequencing era.
ISSN: 1018-4813

hal-01404211
https://hal-univ-bourgogne.archives-ouvertes.fr/hal-01404211
DOI : 10.1038/ejhg.2015.105
PUBMED : 26014430

Éditeur(s) : HAL CCSD
Résumé : International audience
Notre projet ambitionne d'identifier les déterminants institutionnels et situationnels des transitions codiques, phénomène qui correspond à l'enchaînement des canaux de communications auxquels les acteurs de la situation didactique ont recours, les uns pour faire apprendre, les autres pour apprendre. Nous cherchons à en mesurer l'impact sur les apprentissages. Nous exploiterons le cadre théorique de l'action conjointe en didactique pour notre étude. Le dispositif mis en place, croisant entretien et observation réciproque, permettra de nous plonger au coeur de ces transitions. Les premiers résultats obtenus mettent en évidence que les transitions codiques s'organisent selon une direction préférentielle et selon le registre d'action enseignante, qu'elles s'initient dans le recours à des savoirs professionnels et académiques pour ensuite être pilotées dans leur transformation par la dynamique des interactions qui semble dépendre du niveau de maitrise et du genre des élèves. Introduction Notre recherche se focalise sur les interactions enseignant/élèves et se propose d'étudier la dynamique évolutive conjointe des modes de communications qui vont se développer entre ces deux acteurs du système didactique. En EPS, nous pensons que le discours enseignant en situation d'intervention ne peut se réduire à un discours oral. La variété des canaux de
L’intervention en sport et en Education physique face aux transformations sociétales : enjeux, défis, responsabilité de la recherche
Hammamet, France

hal-01620925
https://hal.univ-antilles.fr/hal-01620925
https://hal.univ-antilles.fr/hal-01620925/document
https://hal.univ-antilles.fr/hal-01620925/file/G.%20Marrot%20et%20MP.%20Poggi%20ARIS%202016.pdf

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Chronic liver damage due to viral or chemical agents leads to a repair process resulting in hepatic fibrosis. Fibrosis may lead to cirrhosis, which may progress to liver cancer or a loss of liver function, with an associated risk of liver failure and death. Chlordecone is a chlorinated pesticide used in the 1990s. It is not itself hepatotoxic, but its metabolism in the liver triggers hepatomegaly and potentiates hepatotoxic agents. Chlordecone is now banned, but it persists in soil and water, resulting in an ongoing public health problem in the Caribbean area. We assessed the probable impact of chlordecone on the progression of liver fibrosis in the population of contaminated areas, by developing a mouse model of chronic co-exposure to chlordecone and a hepatotoxic agent, carbon tetrachloride (CCl4). After repeated administrations of chlordecone and CCl4 by gavage over a 12-week period, we checked for liver damage in the exposed mice, by determining serum liver transaminase (AST, ALT) levels, histological examinations of the liver and measuring the expression of genes encoding extracellular matrix components. The co-exposure of mice to CCl4 and chlordecone resulted in significant increases in ALT and AST levels. Chlordecone also increased expression of the Col1A2, MMP-2, TIMP-1 and PAI-1 genes in CCl4-treated mice. Finally, we demonstrated, by quantifying areas of collagen deposition and alpha-SMA gene expression, that chlordecone potentiated the hepatic fibrosis induced by CCl4. In conclusion, our data suggest that chlordecone potentiates hepatic fibrosis in mice with CCl4-induced chronic liver injury
ISSN: 0378-4274

hal-01274228
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01274228
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01274228/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01274228/file/Chlordecone%20potentiates%20hepatic%20fibrosis%20%281%29.pdf
DOI : 10.1016/j.toxlet.2016.02.005

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
Objective: To describe characteristics and outcomes of HIV-infected patients with Pneumocystis jirovecii pneumonia (PCP) over 2004–2011 in France, in particular in those previously enrolled (PE) in the French Hospital Database on HIV (FHDH). Methods: PE patients with an incident PCP were compared with patients with an inaugural PCP revealing HIV infection (reference). Adequate adherence to care was defined as a CD4 measurement at least every 6 months. Immune reconstitution (CD4$200/mm 3) and risk of death were studied using Kaplan-Meier estimates and multivariable Cox proportional hazards models. Results: In a context of a decreasing incidence of PCP, 1259 HIV-infected patients had a PCP diagnosis, and 593 (47%) were PE patients of whom 161 (27%) have had a prior history of AIDS-defining clinical illness (prior ADI). Median time since enrolment was 8 years for PE patients; 74% had received cART. Median proportion of time with adequate adherence to care was 85% (IQR, 66–96) for all FHDH enrollees, but only 45% (IQR, 1–81) for PE patients during the 2 years before PCP. Median CD4 cell count (38/mm 3) and HIV viral load (5.2 log10 copies/ml) at PCP diagnosis did not differ between PE patients and the reference group. Three year mortality rate of 25% was observed for PE prior ADI group, higher than in PE non-prior ADI group (8%) and the reference group (9%) (p,0.0001). In the PE prior ADI group, poor prognosis remained even after adjustment for virological control and immune reconstitution (HR, 2.4 [95%CI, 1.5–3.7]). Conclusion: Almost 50% of PCP diagnoses in HIV-infected patients occurred presently in patients already in care, mainly with a previous cART prescription but with waning adherence to care. Having repeated ADI is contributing to the risk of death beyond its impact on immune reconstitution and viral suppression: special efforts must be undertaken to maintain those patients in care.
ISSN: 1932-6203

Droits : http://creativecommons.org/licenses/by/
hal-01345090
http://hal.upmc.fr/hal-01345090
http://hal.upmc.fr/hal-01345090/document
http://hal.upmc.fr/hal-01345090/file/journal.pone.0094183.PDF
DOI : 10.1371/journal.pone.0094183

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
Adverse pregnancy outcomes entail a large health burden for the mother and offspring; a part of it might be avoided by better understanding the role of environmental factors in their etiology. Our aims were to review the assessment tools to characterize fecundity troubles and pregnancy-related outcomes in human populations and their sensitivity to environmental factors. For each outcome, we reviewed the possible study designs, main sources of bias, and their suggested cures. In terms of study design, for most pregnancy outcomes, cohorts with recruitment early during or even before pregnancy allow efficient characterization of pregnancy-related events, time-varying confounders, and in utero exposures that may impact birth outcomes and child health. Studies on congenital anomalies require specific designs, assessment of anomalies in medical pregnancy terminations, and, for congenital anomalies diagnosed postnatally, follow-up during several months after birth. Statistical analyses should take into account environmental exposures during the relevant time windows; survival models are an appropriate approach for fecundity, fetal loss, and gestational duration/preterm delivery. Analysis of gestational duration could distinguish pregnancies according to delivery induction (and possibly pregnancy-related conditions). In conclusion, careful design and analysis are required to better characterize environmental effects on human reproduction.
ISSN: 0193-936X

hal-01002724
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01002724
DOI : 10.1093/epirev/mxt011
PUBMED : 24363355

Éditeur(s) : HAL CCSD
Résumé : Semi-volatile organic compounds (SVOCs) refer to a broad spectrum of molecules from different chemical families that have numerous properties. They can be used as pesticides, plasticizers, flame retardants, surfactants, lubricants, etc. Consequently, they are introduced in numerous applications in buildings or used daily by the entire population. Once emitted through evaporation or abrasion in the indoor environment or introduced from the outdoors, their chemical or biological degradation is limited, and they persist indoors. This persistence also explains why some SVOCs that were banned a few years ago are still detected in the air and dust inside buildings. In indoor environments, SVOCs are divided between the gas phase, airborne particles, and dust settled on floors and surfaces. SVOCs are of concern due to their established or suspected health effects and their widespread exposure through different environmental media and pathways. The objective of the thesis was to study the concentrations of 66 SVOCs on airborne particles (PM10) and 48 SVOCs in settled dust in two samples of dwellings randomly selected across France. PM10 were sampled during the nationwide housing survey carried out by the French Observatory of indoor air quality in 2003-2005. The dust samples were collected from vacuum cleaner bags during a nationwide survey carried out in French dwellings where at least one child aged 6 months to 6 years lived (2008-2009). The SVOCs to be analyzed had prior been selected using a ranking method based on their toxicity and indoor concentrations. The data analysis focused in particular on the identification of French specificities in terms of detected molecules and measured concentrations. It highlighted some determinants of exposure, e.g., influence of particle size, type of dust collected, dust bioaccessibility, which are not always considered and limit the comparability of results. The measured concentrations were also used to assess the health ranking implemented prior to this work and to confirm its relevance. The concentrations measured both in the air and in settled dust were compared to study the similarities in terms of concentrations and SVOC mixtures. Finally, the exposure doses to SVOCs were calculated for both a child and an adult to assess the respective contributions of inhalation and ingestion to these compounds in particulate phase in dwellings.
Les composés organiques semi-volatils (COSV) font l’objet d’une attention croissante depuis une dizaine d’années. Utilisés dans de nombreux produits et matériaux du quotidien, ils sont émis dans les bâtiments par dispersion lors de l’usage, par évaporation ou abrasion. Du fait de leurs caractéristiques physico-chimiques, ces composés se répartissent à la fois dans l’air, en phases gazeuse et particulaire, et dans les poussières déposées au sol, sur le mobilier et les objets. Compte tenu du temps passé par la population dans les bâtiments, en particulier par les populations sensibles comme les enfants, les femmes enceintes et les personnes âgées, l’exposition à ces substances mérite d’être documentée, tenant compte des voies d’exposition en jeu : inhalation, ingestion et contact cutané. La thèse a porté sur les COSV présents en phase particulaire dans les logements. L’objectif de la thèse visait à exploiter les mesures de 66 COSV dans les particules en suspension de diamètre inférieur à 10 µm (PM10) et de 48 COSV dans les poussières au sol de taille inférieure à 100 µm considérées comme étant celles adhérant à la peau. Ces mesures ont été réalisées dans le cadre de deux campagnes nationales : la campagne « Logements » de l’Observatoire de la qualité de l’air intérieur conduite en 2003-2005 et l’enquête Plomb-Habitat dont les prélèvements ont eu lieu en 2008-2009. Une hiérarchisation des molécules jugées prioritaires au regard de leur impact sanitaire potentiel avait permis au préalable d’établir la liste des COSV à mesurer. L’exploitation de ces données de contamination a notamment porté sur l’identification d’éventuelles spécificités françaises au regard des molécules en présence et/ou des concentrations mesurées. Elle a permis de mettre en lumière un ensemble de facteurs déterminants de l’exposition (influence de la taille des particules, du type de poussières collectées, de leur bioaccessibilité), qui ne sont pas toujours considérés et qui limitent par ailleurs la comparabilité des résultats. Les concentrations mesurées ont aussi permis d’évaluer rétrospectivement la hiérarchisation sanitaire et d’en confirmer la pertinence. Les concentrations des COSV quantifiés à la fois dans l’air et au sol ont été mises en perspective afin d’examiner dans quelle mesure les particules en suspension et les poussières déposées sont similaires en termes de concentrations et de mélanges de COSV en présence. Enfin, l‘estimation des doses d’exposition aux COSV à partir d’équations simples, de variables humaines d’exposition et des données de contamination a permis une première évaluation des contributions respectives de l’inhalation et de l’ingestion aux expositions domestiques des enfants et adultes à ces composés en phase particulaire.
https://tel.archives-ouvertes.fr/tel-01308524

NNT : 2015REN1B033
tel-01308524
https://tel.archives-ouvertes.fr/tel-01308524
https://tel.archives-ouvertes.fr/tel-01308524/document
https://tel.archives-ouvertes.fr/tel-01308524/file/MANDINCorinne.pdf

Éditeur(s) : HAL CCSD Université des Antilles
Résumé : International audience
Les quarante-quatre jours de conflits, de grèves, de manifestations, et de blocages économiquesà l’initiative du collectif guadeloupéen « Liyannaj Kont Pwofitasyon » (LKP) qui ont marquéles opinions sont le reflet des crises sociales, économiques, voire politiques et identitairesCrises et conflits dans les territoires insulaires de la Caraïbe et de l’Océan Indien (20 (...) 3Études caribéennes, 17 | Décembre 2010qui secouent les Départements et Régions d’Outre-Mer mais aussi de nombreux territoiresinsulaires. En Guadeloupe, au cours de cette mobilisation d’envergure, des dizaines de milliersde manifestants organisés derrière le collectif LKP regroupant près de cinquante organisationsculturelles, politiques et syndicales, ont revendiqué une hausse du pouvoir d’achat avec pourleitmotive la lutte contre « la vie chère ». Ces crises qui impactent les territoires insulairesont souvent une cause lointaine, globale, multiforme. D’autres ont participé activement audéclenchement de cette crise mondiale, notamment certains paradis fiscaux à l’origine de lafaillite des subprimes.
ISSN: 1779-0980

hal-01203236
https://hal.archives-ouvertes.fr/hal-01203236
https://hal.archives-ouvertes.fr/hal-01203236/document
https://hal.archives-ouvertes.fr/hal-01203236/file/etudescaribeennes-5013-17-crises-et-conflits-dans-les-territoires-insulaires-de-la-caraibe-et-de-l-ocean-indien-2009-2010.pdf

Éditeur(s) : HAL CCSD Elsevier
Résumé : URL de l'article : http://www.sciencedirect.com/science/article/B6WPN-4XY3KDK-2/2/fd8508af63d82e29b4f9829c65194e26
The impact of climatic changes that occurred during the last glacial maximum and the Holocene on vegetation changes in the Amazon Basin and the Guiana Shield are still widely debated. The aim of our study was to investigate whether major changes in vegetation (i.e. transitions between rainforests and C4 savannas) occurred in northern French Guiana during the Holocene. We measured variations in the δ13C of soil organic matter at eight sites now occupied by forest or savannah. The forest sites were selected to cover two regions (forest refugia and peneplains) which are thought to have experienced different intensities of disturbance during the latest Pleistocene and the Holocene. We found that none of the forest sites underwent major disturbances during the Holocene, i.e. they were not replaced by C4 savannahs or C4 forest savannahs for long periods. Our results thus suggest that tropical rainforests in northern French Guiana were resilient to drier climatic conditions during the Holocene. Nevertheless, geographical and vertical variations in the 13C of SOM were compatible with minor changes in vegetation, variations in soil processes or in soil physical properties.
ISSN: 0033-5894

halshs-00551758
https://halshs.archives-ouvertes.fr/halshs-00551758
DOI : 10.1016/j.yqres.2009.11.007

Éditeur(s) : HAL CCSD BioMed Central
Résumé : [b]Background[/b]: [i]Amblyomma variegatum[/i] and [i]A. hebraeum[/i] are two ticks of veterinary and human health importance in south-east Africa. In Zimbabwe they occupy parapatric (marginally overlapping and juxtaposed) distributions. Understanding the mechanisms behind this parapatry is essential for predicting the spatio-temporal dynamics of Amblyomma spp. and the impacts of associated diseases. It has been hypothesized that exclusive competition between these species results from competition at the levels of male signal reception (attraction-aggregation-attachment pheromones) or sexual competition for mates. This hypothesis predicts that the parapatry described in Zimbabwe could also be present in other countries in the region. [br/][b]Methods[/b]: To explore this competitive exclusion hypothesis we conducted field surveys at the two species' range limits in Mozambique to identify areas of sympatry (overlapping areas) and to study potential interactions (communicative and reproductive interference effects) in those areas. At sympatric sites, hetero-specific mating pairs were collected and inter-specific attractiveness/repellent effects acting at long and short distances were assessed by analyzing species co-occurrences on co-infested herds and co-infested hosts.[br/] [b]Results[/b]: Co-occurrences of both species at sampling sites were infrequent and localized in areas where both tick and host densities were low. At sympatric sites, high percentages of individuals of both species shared attachment sites on hosts and inter-specific mating rates were high. Although cross-mating rates were not significantly different for[i] A. variegatum[/i] and [i]A. hebraeum[/i] females, attraction towards hetero-specific males was greater for [i]A. hebraeum[/i] females than for A. variegatum females and we observed small asymmetrical repellent effects between males at attachment sites.[br/][b]Conclusions[/b]: Our observations suggest near-symmetrical reproductive interference between [i]A. variegatum[/i] and [i]A. hebraeum[/i], despite between-species differences in the strength of reproductive isolation barriers acting at the aggregation, fixation and partner contact levels. Theoretical models predict that sexual competition coupled with hybrid inviability, greatly reduces the probability of one species becoming established in an otherwise suitable location when the other species is already established. This mechanism can explain why the parapatric boundary in Mozambique has formed within an area of low tick densities and relatively infrequent host-mediated dispersal events.
ISSN: 1756-3305

hal-01220744
https://hal.archives-ouvertes.fr/hal-01220744
https://hal.archives-ouvertes.fr/hal-01220744/document
https://hal.archives-ouvertes.fr/hal-01220744/file/2015%20Bournez%20Parasites%20%26%20Vectors_%7B365AAFF5-7041-480B-9B77-9CD0485A9B72%7D.pdf
DOI : 10.1186/s13071-015-1116-7

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
Basal cell carcinoma (BCC) is the commonest tumor in human. About 70% sporadic BCCs bear somatic mutations in the PATCHED1 tumor suppressor gene which encodes the receptor for the Sonic Hedgehog morphogen (SHH). PATCHED1 germinal mutations are associated with the dominant Nevoid Basal Cell Carcinoma Syndrome (NBCCS), a major hallmark of which is a high susceptibility to BCCs. Although the vast majority of sporadic BCCs arises exclusively in sun exposed skin areas, 40 to 50% BCCs from NBCCS patients develop in non photo-exposed skin. Since overwhelming evidences indicate that microenvironment may both be modified by- and influence the- epithelial tumor, we hypothesized that NBCCS fibroblasts could contribute to BCCs in NBCCS patients, notably those developing in non photo-exposed skin areas. The functional impact of NBCCS fibroblasts was then assessed in organotypic skin cultures with control keratinocytes. Onset of epidermal differentiation was delayed in the presence of primary NBCCS fibroblasts. Unexpectedly, keratinocyte proliferation was severely reduced and showed high levels of nuclear P53 in both organotypic skin cultures and in fibroblast-led conditioning experiments. However, in spite of increased levels of senescence associated β-galactosidase activity in keratinocytes cultured in the presence of medium conditioned by NBCCS fibroblasts, we failed to observe activation of P16 and P21 and then of bona fide features of senescence. Constitutive extinction of P53 in WT keratinocytes resulted in an invasive phenotype in the presence of NBCCS fibroblasts. Finally, we found that expression of SHH was limited to fibroblasts but was dependent on the presence of keratinocytes. Inhibition of SHH binding resulted in improved epidermal morphogenesis. Altogether, these data suggest that the repertoire of diffusible factors (including SHH) expressed by primary NBCCS fibroblasts generate a stress affecting keratinocytes behavior and epidermal homeostasis. Our findings suggest that defects in dermo/epidermal interactions could contribute to BCC susceptibility in NBCCS patients.
ISSN: 1932-6203

Droits : http://creativecommons.org/licenses/by/
hal-01257867
http://hal.upmc.fr/hal-01257867
http://hal.upmc.fr/hal-01257867/document
http://hal.upmc.fr/hal-01257867/file/journal.pone.0145369.pdf
DOI : 10.1371/journal.pone.0145369

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : Tropical forests determine global biogeochemical cycles to a large extent, but control factors for key ecosystem processes such as decomposition remain poorly understood. With a full-factorial C (cellulose), N (urea), and P (phosphate) fertilization experiment, we tested the relative importance of C and nutrient limitation on litter decomposition in a mature lowland moist forest of French Guiana. Despite the previously demonstrated litter C quality control over decomposition and the very low soil P content (0.1 mg g(-1) of soil) at our study site, fertilization with C or P alone did not increase the decomposition of a wide range of litter types (N:P ratios between 20 and 80). Nitrogen fertilization alone also had no effect on decomposition. However, the combined fertilization with N and P resulted in up to 33.5% more initial litter mass lost, with an increasing effect with wider litter N:P ratios. Soil fauna strongly stimulated litter mass loss and enhanced nutrient fertilization effects. Moreover, nutrient effects on decomposition increased with additional C fertilization in the presence of fauna. Our results suggest that increased N availability is required for a positive P effect on decomposition in the studied P-poor tropical forest. Further stimulation of decomposition by C amendment through priming indicates energy limitation of decomposers that is co-determined by nutrient availability. The demonstrated intricate control of the key resources C, N, and P on decomposition calls for an intensified research effort on multiple resource limitation on key processes in tropical forests and how they change under multiple human impacts.
ISSN: 1432-9840

hal-01032414
https://hal.archives-ouvertes.fr/hal-01032414
DOI : 10.1007/s10021-012-9564-9