Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
Previous work has demonstrated that geoelectrical measurements, acquired either along the Earth’s surface or in boreholes, can be sensitive to the presence of fractures. However, a lack of numerical approaches that are well suited to modelling electric current flow in fractured media prevents us from systematically exploring the links between geoelectrical measurements and fractured rock properties. To address this issue, we present a highly computationally efficient methodology for the numerical simulation of geoelectrical data in 2.5-D in complex fractured domains. Our approach is based upon a discrete-dual-porosity formulation, whereby the fractures and rock matrix are treated separately and coupled through the exchange of electric current between them. We first validate our methodology against standard analytical and finite-element solutions. Subsequent use of the approach to simulate geoelectrical data for a variety of different fracture configurations demonstrates the sensitivity of these data to important parameters such as the fracture density, depth, and orientation.
ISSN: 0956-540X

hal-01622151
https://hal.archives-ouvertes.fr/hal-01622151
https://hal.archives-ouvertes.fr/hal-01622151/document
https://hal.archives-ouvertes.fr/hal-01622151/file/sanzGJI2017.pdf
DOI : 10.1093/gji/ggx080

Éditeur(s) : HAL CCSD Elsevier - Oxford University Press
Résumé : International audience
Meeting Abstract: P171
ISSN: 1873-9946

hal-01359565
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01359565
DOI : 10.1093/ecco-jcc/jjw019.290

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
We present new archaeointensity results from three Italian kilns situated at Ascoli Satriano, Vagnari and Fontanetto Po obtained with the Thellier modified by Coe double heating method. These data complement the directional results previously published. All sites are dated on the basis of archaeological information and/or thermoluminescence dating. The results are corrected for the anisotropy of the thermoremanent magnetization and the cooling rate effects. The new data are compared with previously published archaeointensity data from Italy and nearby countries within 900 km radius from Viterbo. An initial data set including archaeointesity data mainly coming from Italy, France, Switzerland, Czech Republic, Slovakia, Hungary, Greece and Bulgaria has been compiled. After the application of strict selection criteria, the most reliable data have been used for the calculation of a preliminary Italian intensity secular variation (SV) curve for the last 3000 yr. The new curve covers the 300 BC-400 AD and 1200-1900 AD periods. It is established by means of sliding windows of 200 yr shifted by 100 yr. The lack of reliable data for the 1000-200 BC and 400-1200 AD time intervals does not permit the calculation of a continuous curve. Clearly, more high-quality archaeointensity data from Italy and Europe are still needed to draw a robust intensity SV curve for the Italian Peninsula that could be used for archaeomagnetic dating in combination with the directional data.
ISSN: 0956-540X

hal-00828691
https://hal.archives-ouvertes.fr/hal-00828691
DOI : 10.1093/gji/ggs120

Éditeur(s) : HAL CCSD Oxford University Press
Résumé : International audience
Brain Aromatase, Estrogens, and Behavior

hal-01122072
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01122072

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : Architectural analyses of temperate tree species using a chronological approach suggest that the expression of epicormic branches is closely related to low growth rates in the axes that make up the branching system. Therefore, sole consideration of epicormic criteria may be sufficient to identify trees with low secondary growth levels or with both low primary and secondary growth levels. In a tropical tree such as Dicorynia guianensis (basralocus), where chronological studies are difficult, this relationship could be very useful as an easily accessible indicator of growth potentials. A simple method of architectural tree description was used to characterize the global structure of more than 1650 basralocus trees and to evaluate their growth level. Measurements of simple growth characters [height, basal diameter, internode length of submittal part (top of the main axis of the tree)] and the observation of four structural binary descriptors on the main stem (presence of sequential branches and young epicormic branches, state of the submittal part, global orientation), indicated that epicormic branch formation is clearly related to a decrease in length of the successive growth units of the main stem. Analysis of height vs. diameter ratios among different tree subgroups, with and without epicormic branching, suggested that trees with epicormic branches generally have a low level of secondary growth compared with primary growth.
ISSN: 0305-7364

hal-01032037
https://hal.archives-ouvertes.fr/hal-01032037
DOI : 10.1093/aob/mcg119

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
STUDY QUESTION: Is prenatal exposure to persistent organic pollutants (POPs) associated with variations of sex hormone levels in cord blood? SUMMARY ANSWER: Prenatal exposure to a number of POPs is associated with a disruption of hormone levels in cord blood, with sex specificities. WHAT IS KNOWN ALREADY: Epidemiological studies have reported disorders of reproductive health, in relation with POPs exposure during early life and the endocrine disruption properties of these chemicals have been suggested as possible mechanisms. STUDY DESIGN, SIZE, DURATION: A subset of 282 mother-child pairs was selected from the prospective population-based PELAGIE birth cohort (n = 3421, 2002-2006, Brittany, France). Pregnant women were recruited before 19 weeks of gestation and followed until delivery. PARTICIPANTS/MATERIALS, SETTING, METHODS: Sex hormone levels including sex hormone-binding globulin (SHBG), estradiol (E2), total testosterone (T), free testosterone (fT = T/SHBG) and the aromatase index (AI = T/E2) were measured in 282 cord blood samples. Anti-Müllerian hormone (AMH) was measured in male newborns only. Pesticide concentrations of α-endosulfan, β-hexachlorocyclohexane (β-HCH), γ-HCH, dieldrin, pp'-dichlorodiphenyldichloroethylene (p,p'-DDE), hexachlorobenzene (HCB), heptachlor epoxide (HCE), as well as PCBs (congeners 153, 187 and the sum of anti-estrogenic PCBs 118, 138, and 170) and decabrominated diphenyl ether (BDE209) were also measured in cord blood. Associations between sex hormones and POPs exposure were explored using multiple linear regressions adjusted for potential confounders. MAIN RESULTS AND THE ROLE OF CHANCE: High PCB levels were associated with an increase of SHBG (P-trend extless 0.01) and AMH (P-trend extless 0.05) and a decrease of fT (P-trend extless 0.05) and AI (P-trend extless 0.01). High pesticide levels, particularly α-endosulfan and HCE, were associated with an increase of SHBG (P extless 0.05) and E2 (P extless 0.01) and a decrease of fT (P extless 0.05) and AI (P extless 0.01). Several of these associations were stronger, or specific, among male or female newborns. The associations were not altered in the sensitivity analyses. LIMITATIONS, REASONS FOR CAUTION: The study population was of relatively small sample size, and some compounds rarely detected in cord blood. The high level of correlation between POPs makes it difficult to identify the most contributing POPs. Hormone measurements were performed at birth (in cord blood) and may not adequately represent the infant endocrine system. Multiple statistical testing may have led to false-positive associations. WIDER IMPLICATIONS OF THE FINDINGS: Our results are in discordance with those reported in the only published study of the kind but in accordance with studies about prenatal exposure to other endocrine disruptors such as phthalates. These findings may help understanding the pathways involved in adverse reproductive outcomes associated with POPs exposure. STUDY FUNDING/COMPETING INTERESTS: The PELAGIE cohort is funded by Inserm, French Ministry of Health, French Ministry of Labor, InVS, ANR, ANSES, and French Ministry of Ecology. None of the authors has any competing interest to declare
ISSN: 0268-1161

hal-01220641
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01220641
DOI : 10.1093/humrep/dev260
PUBMED : 26493407

Éditeur(s) : HAL CCSD Oxford University Press (OUP): Policy B - Oxford Open Option B
Résumé : absent
ISSN: 0829-318X

hal-01032253
https://hal.archives-ouvertes.fr/hal-01032253

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
Estimating how topography is maintained provides insights into the different factors responsible for surface deformations and their relative roles. Here, we develop a new and simple approach to assess the degree of isostatic compensation of continental topography at regional scale from GOCE gravity gradients. We calculate the ratio between the radial gradient observed by GOCE and that calculated from topography only. From analytical and statistical formulations, simple relationships between this ratio and the degree of compensation are obtained under the Airy–Heiskanen isostasy hypothesis. Then, a value of degree of compensation at each point of study area can be easily deduced. We apply our method to the Alaska-Canada Cordillera and validate our results by comparison with a standard isostatic gravity anomaly model and additional geophysical information for this area. Both our GOCE-based results and the isostatic anomaly show that Airy–Heiskanen isostasy prevails for the Yukon Plateau whereas additional mechanisms are required to support topography below the Northwest Territories Craton and the Yakutat collision zone.
ISSN: 0956-540X

hal-01467540
https://hal.archives-ouvertes.fr/hal-01467540
https://hal.archives-ouvertes.fr/hal-01467540/document
https://hal.archives-ouvertes.fr/hal-01467540/file/cadioGJI2016.pdf
DOI : 10.1093/gji/ggw281

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
BACKGROUND: Mammalian spermatogenesis is a process that involves a complex expression program in both somatic and germ cells present in the male gonad. A number of studies have attempted to define the transcriptome of male meiosis and gametogenesis in rodents and primates. Few human transcripts, however, have been associated with testicular somatic cells and germ cells at different post-natal developmental stages and little is known about their level of germline-specificity compared with non-testicular tissues. METHODS: We quantified human transcripts using GeneChips and a total of 47 biopsies from prepubertal children diagnosed with undescended testis, infertile adult patients whose spermatogenesis is arrested at consecutive stages and fertile control individuals. These results were integrated with data from enriched normal germ cells, non-testicular expression data, phenotype information, predicted regulatory DNA-binding motifs and interactome data. RESULTS: Among 3580 genes for which we found differential transcript concentrations in somatic and germ cells present in human testis, 933 were undetectable in 45 embryonic and adult non-testicular tissues, including many that were corroborated at protein level by published gene annotation data and histological high-throughput protein immunodetection assays. Using motif enrichment analyses, we identified regulatory promoter elements likely involved in germline development. Finally, we constructed a regulatory disease network for human fertility by integrating expression signals, interactome information, phenotypes and functional annotation data. CONCLUSIONS: Our results provide broad insight into the post-natal human testicular transcriptome at the level of cell populations and in a global somatic tissular context. Furthermore, they yield clues for genetic causes of male infertility and will facilitate the identification of novel cancer/testis genes as targets for cancer immunotherapies.
ISSN: 0268-1161

hal-00877243
https://hal.archives-ouvertes.fr/hal-00877243
DOI : 10.1093/humrep/des301
PUBMED : 22926843

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
Motivation: Gene fusion is an important evolutionary process. It can yield valuable information to infer the interactions and functions of proteins. Fused genes have been identified as non-transitive patterns of similarity in triplets of genes. To be computationally tractable, this approach usually imposes an a priori distinction between a dataset in which fused genes are searched for, and a dataset that may have provided genetic material for fusion. This reduces the `genetic space' in which fusion can be discovered, as only a subset of triplets of genes is investigated. Moreover, this approach may have a high-false-positive rate, and it does not identify gene families descending from a common fusion event. Results: We represent similarities between sequences as a network. This leads to an efficient formulation of previous methods of fused gene identification, which we implemented in the Python program FusedTriplets. Furthermore, we propose a new characterization of families of fused genes, as clique minimal separators of the sequence similarity network. This well-studied graph topology provides a robust and fast method of detection, well suited for automatic analyses of big datasets. We implemented this method in the C++ program MosaicFinder, which additionally uses local alignments to discard false-positive candidates and indicates potential fusion points. The grouping into families will help distinguish sequencing or prediction errors from real biological fusions, and it will yield additional insight into the function and history of fused genes.
ISSN: 1367-4803

hal-01544795
https://hal.archives-ouvertes.fr/hal-01544795
DOI : 10.1093/bioinformatics/btt049

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
AIM: To describe the main characteristics and the treatment of cryptococcosis in patients with sarcoidosis. DESIGN: Multicenter study including all patients notified at the French National Reference Center for Invasive Mycoses and Antifungals. METHODS: Retrospective chart review. Each case was compared with two controls without opportunistic infections. RESULTS: Eighteen cases of cryptococcosis complicating sarcoidosis were analyzed (13 men and 5 women). With 2749 cases of cryptococcosis registered in France during the inclusion period of this study, sarcoidosis accounted for 0.6% of all the cryptococcosis patients and for 2.9% of the cryptococcosis HIV-seronegative patients. Cryptococcosis and sarcoidosis were diagnosed concomitantly in four cases; while sarcoidosis was previously known in 14/18 patients, including 12 patients (67%) treated with steroids. The median rate of CD4 T cells was 145 per mm(3) (range: 55-1300) and not related to steroid treatment. Thirteen patients had cryptococcal meningitis (72%), three osteoarticular (17%) and four disseminated infections (22%). Sixteen patients (89%) presented a complete response to antifungal therapy. After a mean follow-up of 6 years, no death was attributable to cryptococcosis. Extra-thoracic sarcoidosis and steroids were independent risk factors of cryptococcosis in a logistic regression model adjusted with the sex of the patients. CONCLUSIONS: Cryptococcosis is a significant opportunistic infection during extra-thoracic sarcoidosis, which occurs in one-third of the cases in patients without any treatment; it is not associated to severe CD4 lymphocytopenia and has a good prognosis.
ISSN: 1460-2725

hal-00873410
https://hal.archives-ouvertes.fr/hal-00873410
DOI : 10.1093/qjmed/hct052
PUBMED : 23515400

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
OBJECTIVES: The aims of the study were to assess in patients with advanced HIV disease receiving antiretroviral therapy (ART) intensification with enfuvirtide (i) resistance at virological failure (VF), (ii) impact of baseline tropism on immunovirological response, and (iii) HIV-1 DNA tropism evolution during ART. METHODS: The ANRS 130 APOLLO randomized trial evaluated in naive patients the immunovirological impact of standard ART without (control arm) or with enfuvirtide. Tropism was determined on RNA and DNA by V3-loop sequencing interpreted using the Geno2Pheno algorithm. RESULTS: At baseline the median CD4 cell count was 30 cells/mm(3). Among the 170 patients assessable in this virological substudy, HIV-1 RNA tropism was as follows: 60% of viruses were R5 and 40% were R5X4/X4. HIV-1 DNA tropism was as follows: 54% were R5 and 46% were R5X4/X4. At week 24, 39% and 49% of patients experienced VF in the enfuvirtide and control arms, respectively. In the enfuvirtide arm, only resistance-associated mutations to enfuvirtide were detected. In the control arm, two patients displayed drug-resistant viruses at the time of VF. No impact of baseline tropism was observed on immunovirological response, regardless of the study arm. Among the 25 patients experiencing DNA tropism switch between baseline and week 24, 16 (64%) switched from R5 to R5X4/X4. These latter were mostly successfully suppressed patients receiving enfuvirtide and exhibiting poorer immunological response. CONCLUSIONS: Baseline RNA tropism had no impact on the immunovirological response. Drug resistance mutations were only detected for the fusion inhibitor. Finally, the mechanism of replenishment of the viral cellular reservoir with X4 viruses observed needs to be further analysed.
ISSN: 0305-7453

hal-00875130
https://hal.archives-ouvertes.fr/hal-00875130
DOI : 10.1093/jac/dks455
PUBMED : 23152480

Éditeur(s) : HAL CCSD Oxford University Press (OUP): Policy B1 - Oxford Open Option B Oxford University Press (OUP)
Résumé : International audience
BACKGROUNDA very large proportion of the literature on the endocrine disruptors categorized as anti-androgens deals with phthalates, which are produced in large amounts for use as plastic emollients and additives. In this review, we bring together and analyse work on the effects of phthalates in animals and humans at different stages of their development to assess whether or not their possible anti-androgenic properties represent a significant threat to human health.METHODSThe database PubMed was systematically searched for all English language articles until July 2013 in each subject area discussed.RESULTSWe provide an up-to-date exhaustive, comparative and critical assessment of both in vivo and in vitro studies undertaken to explore the effects of phthalates on the human testis from fetal life to adulthood. These results are compared and discussed in the light of the key data reported in the literature for mice and rats.CONCLUSIONSThe current literature highlights the fact that (i) there is a huge difference between the number of studies performed in animals and in humans, with many fewer for humans; (ii) there are differences in the way rats, mice, primates and humans respond to phthalates, for reasons that need to be further explored; (iii) more work is required to clarify the contradictions, in the few existing human epidemiological studies at all stages of development, which may be partly explained by varying methods of exposure assessment; (iv) in accordance with recent findings in rodents, it cannot be excluded that transgenerational effects of phthalates and/or epigenetic changes exist in humans; (v) a number of methodological limitations need to be solved for the in vitro and xenografting models using human fetal testis to fulfil their 'missing link' role between epidemiological studies in humans and rodent models; and (vi) epidemiological and in vitro studies generally converge sufficiently to conclude that phthalate anti-androgenicity is plausible in adult men.
ISSN: 1355-4786

inserm-00869540
http://www.hal.inserm.fr/inserm-00869540
DOI : 10.1093/humupd/dmt050
PUBMED : 24077978

Éditeur(s) : HAL CCSD Oxford University Press (OUP): Policy B - Oxford Open Option A Oxford University Press (OUP)
Résumé : International audience
Peridotites exhumed in the footwall of axial detachment faults at slow-spreading ridges are highly serpentinized. Most mid-ocean ridge detachment settings are magmatically active and hydrous fluid circulation in and near the fault has been shown to be influenced by the presence of melt or magmatic lithologies. Our working area along the Southwest Indian Ridge (62–65°E) is nearly amagmatic and represents an end-member to study the hydrous alteration of exhumed peridotites without these magmatic influences. We use an integrated petrological approach combining microstructural, mineralogical and chemical observations to unravel the sequence of serpentinization in 272 dredged samples of variably serpentinized peridotites and to document the circulation of serpentinizing fluids in and near the exhumation faults. We find that serpentine recrystallization and veins overprint the initial serpentinite mesh texture in ∼25% of the samples. Oxygen isotope data suggest that this sequence developed at relatively high temperatures (271–336°C) and under increasing fluid–rock ratios, from near stoichiometry for mesh texture formation to >10 during recrystallization. Increasing fluid supersaturation relative to serpentine favors the replacement of mesh texture lizardite by chrysotile and polygonal or polyhedral serpentine. We attribute local recrystallization into antigorite to moderate Si-metasomatism, possibly following pyroxene serpentinization. We do not observe the more pronounced Si-metasomatism leading to talc replacing serpentine that is reported for the more magmatically active Mid-Atlantic Ridge detachment settings and is attributed to prior leaching of magmatic rocks. Scales of preferential fluid pathways in our samples evolved from pervasive and close-spaced (<500 µm) microfractures during the formation of the initial serpentine mesh texture, to centimeter-thick planar domains of enhanced fluid flux, spaced at ∼10 cm intervals and probably grouped in corridors that may be up to ∼100 m across. Serpentine minerals are enriched in some fluid-mobile elements (Cl, B, U) relative to the peridotite protolith, and several elements (Al, Fe, Si, Cu, As, Sb, REE) are redistributed at the millimeter to decimeter scale. Serpentinizing fluids were seawater-derived, probably mildly alkaline (small to no europium anomalies), reducing and H2-enriched (formation of magnetite). These fluids may have been similar to, though warmer than, those venting at the ultramafic-hosted Lost City hydrothermal fluid (30°N, Mid-Atlantic Ridge).
ISSN: 0022-3530

hal-01174047
https://hal.archives-ouvertes.fr/hal-01174047
DOI : 10.1093/petrology/egv014

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
This study describes the structure of the digestive gland of Strombus gigas in individuals from Guadeloupe and discusses the function of its cell types and their relationship with intracellular Apicomplexa-like parasites. Three cellular types were found in the epithelium of the blind-ending tubules of the digestive gland according to histological and transmission electron microscopy (TEM) observations; these were: digestive cells, pyramidal crypt cells and vacuolated cells. Columnar digestive cells were characterized by large Alcian blue-positive granules, which have not been previously described in digestive cells of other caenogastropods. Such granules contain large quantities of proteoglycans that are exported to the stomach through the physiological destruction of the digestive cells, which undergo a holocrine secretion. Their cytoplasm appears vacuolar due to lipid extraction by solvents used for tissue preparation. Vacuolated cells also appear to be lipid-storage cells. Small triangular-shaped crypt cells, on the other hand, appear to be metabolically active as suggested by a strong positive in situ hybridization of eukaryotic ribosomes, which was confirmed by their large content of ribosomes and rough endoplasmic reticulum compared to the other cell types. These observations suggest that crypt cells may be immature cells that are involved in the replacement of eliminated digestive cells. However, their spherocrystal inclusions indicate that they may be excretory cells or calcium cells. Large brown inclusions were frequently observed in vacuolated cells; these were identified as parasitic protozoans and were present in the digestive gland of all sampled specimens. These protozoans have previously been described from a queen conch population in the San Andres Archipelago (Colombia). Several life cycle stages of the parasite were identified by scanning electron microscopy and TEM; trophozoites were characterized by their conoid-like structure, sporocysts by their thick walls, and gamonts by their thin walls. These observations suggest that this parasite completes its entire life cycle within the same host and type of tissue. Although previous investigations place this parasite within the Apicomplexa group, further investigations are necessary in order to confirm the identification of the parasite.
ISSN: 0260-1230

hal-00755287
https://hal.univ-antilles.fr/hal-00755287
DOI : 10.1093/mollus/eyn041

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
Rifting in a cratonic lithosphere is strongly controlled by several interacting processes including crust/mantle rheology, magmatism, inherited structure and stress regime. In order to better understand how these physical parameters interact, a 2 yr long seismological experiment has been carried out in the North Tanzanian Divergence (NTD), at the southern tip of the eastern magmatic branch of the East African rift, where the southward-propagating continental rift is at its earliest stage. We analyse teleseismic data from 38 broad-band stations ca. 25 km spaced and present here results from their receiver function (RF) analysis. The crustal thickness and Vp/Vs ratio are retrieved over a ca. 200 × 200 km2 area encompassing the South Kenya magmatic rift, the NTD and the Ngorongoro-Kilimanjaro transverse volcanic chain. Cratonic nature of the lithosphere is clearly evinced through thick (up to ca. 40 km) homogeneous crust beneath the rift shoulders. Where rifting is present, Moho rises up to 27 km depth and the crust is strongly layered with clear velocity contrasts in the RF signal. The Vp/Vs ratio reaches its highest values (ca. 1.9) beneath volcanic edifices location and thinner crust, advocating for melting within the crust. We also clearly identify two major low-velocity zones (LVZs) within the NTD, one in the lower crust and the second in the upper part of the mantle. The first one starts at 15–18 km depth and correlates well with recent tomographic models. This LVZ does not always coexist with high Vp/Vs ratio, pleading for a supplementary source of velocity decrease, such as temperature or composition. At a greater depth of ca. 60 km, a mid-lithospheric discontinuity roughly mimics the step-like and symmetrically outward-dipping geometry of the Moho but with a more slanting direction (NE–SW) compared to the NS rift. By comparison with synthetic RF, we estimate the associated velocity reduction to be 8–9 per cent. We relate this interface to melt ponding, possibly favouring here deformation process such as grain-boundary sliding (EAGBS) due to lithospheric strain. Its geometry might have been controlled by inherited lithospheric fabrics and heterogeneous upper mantle structure. We evidence that crustal and mantle magmatic processes represent first order mechanisms to ease and locate the deformation during the first stage of a cratonic lithospheric breakup.
ISSN: 0956-540X

hal-01622078
https://hal.archives-ouvertes.fr/hal-01622078
https://hal.archives-ouvertes.fr/hal-01622078/document
https://hal.archives-ouvertes.fr/hal-01622078/file/plasmanGJI2017.pdf
DOI : 10.1093/gji/ggx177

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
Advances in groundwater storage monitoring are crucial for water resource management and hydrological processes understanding. The evaluation of water storage changes (WSC) often involve point measurements (observation wells, moisture probes, etc.), which may be inappropriate in heterogeneous media. Over the past few years, there has been an increasing interest in the use of gravimetry for hydrological studies. In the framework of the GHYRAF (Gravity and Hydrology inAfrica) project, 3 yr of repeated absolute gravity measurements using a FG5-type gravimeter have been undertaken at Nalohou, a Sudanian site in northern Benin. Hydrological data are collected within the long-term observing system AMMA-Catch. Once corrected for solid earth tides, ocean loading, air pressure effects, polar motion contribution and non-local hydrology, seasonal gravity variations reach up to 11 μGal, equivalent to a WSC of 260-mm thick infinite layer of water. Absolute temporal gravity data are compared to WSC deduced from neutron probe and water-table variations through a direct modelling approach. First, we use neutronic measurements available for the whole vertical profile where WSC occur (the vadose zone and a shallow unconfined aquifer). The RMSD between observed and modelled gravity variations is 1.61 μGal, which falls within the error bars of the absolute gravity data. Second, to acknowledge for the spatial variability of aquifer properties, we use a 2-D model for specific yield (Sy) derived from resistivity mapping and Magnetic Resonance Soundings (MRS). The latter provides a water content (θMRS) known to be higher than the specific yield. Hence, we scaled the 2-D model of θMRS with a single factor (α). WSC are calculated from water-table monitoring in the aquifer layer and neutronic measurements in the vadose layer. The value of α is obtained with aMonte-Carlo sampling approach, minimizing the RMSD between modelled and observed gravity variations. This leads to α = Sy/θMRS = 0.63 ± 0.15, close to what is found in the literature on the basis of pumping tests experiments, with a RMSD value of 0.94 μGal. This hydrogeophysical experiment is a first step towards the use of time-lapse gravity data as an integrative tool to monitor interannual WSC even in complicated subsurface distribution.
ISSN: 0956-540X

hal-00821181
https://hal.archives-ouvertes.fr/hal-00821181
DOI : 10.1093/gji/ggt146

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
Prostate cancer disparities have been reported in men of African descent who show the highest incidence, mortality, compared with other ethnic groups. Few studies have explored the genetic and environmental factors for prostate cancer in men of African ancestry. The glutathione-S-transferases family conjugates carcinogens before their excretion and is expressed in prostate tissue. This study addressed the role of GSTM1 and GSTT1 deletions on prostate cancer risk in populations of African descent. This multi-institutional case-control study gathered data from the Genetic Susceptibility to Environmental Carcinogens (GSEC) database, the African-Caribbean Cancer Consortium (AC3) and Men of African Descent and Carcinoma of the Prostate Consortium (MADCaP). The analysis included 10 studies (1715 cases and 2363 controls), five in African-Americans, three in African-Caribbean and two in African men. Both the GSTM1 and the GSTT1 deletions showed significant inverse associations with prostate cancer [odds ratio (OR): 0.90, 95% confidence interval (CI) 0.83-0.97 and OR 0.88, 95% CI: 0.82-0.96, respectively]. The association was restricted to Caribbean and African populations. A significant positive association was observed between GSTM1 deletion and prostate cancer in smokers in African-American studies (OR: 1.28, 95% CI: 1.01-1.56), whereas a reduced risk was observed in never-smokers (OR: 0.66, 95% CI: 0.46-0.95). The risk of prostate cancer increased across quartiles of pack-years among subjects carrying the deletion of GSTM1 but not among subjects carrying a functional GSTM1. Gene-environment interaction between smoking and GSTM1 may be involved in the etiology of prostate cancer in populations of African descent.
ISSN: 0143-3334

hal-00682901
https://hal.archives-ouvertes.fr/hal-00682901
DOI : 10.1093/carcin/bgr119
PUBMED : 21705483

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
We carried out morphotectonic studies along the left-lateral strike-slip Bogd Fault, the principal structure involved in the Gobi-Altay earthquake of 1957 December 4 (published magnitudes range from 7.8 to 8.3). The Bogd Fault is 260 km long and can be subdivided into five main geometric segments, based on variation in strike direction. West to East these segments are, respectively: the West Ih Bogd (WIB), The North Ih Bogd (NIB), the West Ih Bogd (WIB), the West Baga Bogd (WBB) and the East Baga Bogd (EBB) segments. Morphological analysis of offset streams, ridges and alluvial fans-particularly well preserved in the arid environment of the Gobi region-allows evaluation of late Quaternary slip rates along the different faults segments. In this paper, we measure slip rates over the past 200 ka at four sites distributed across the three western segments of the Bogd Fault. Our results show that the left-lateral slip rate is similar to 1 mm yr(-1) along the WIB and EIB segments and similar to 0.5 mm yr(-1) along the NIB segment. These variations are consistent with the restraining bend geometry of the Bogd Fault.;Our study also provides additional estimates of the horizontal offset associated with the 1957 earthquake along the western part of the Bogd rupture, complementing previously published studies. We show that the mean horizontal offset associated with the 1957 earthquake decreases progressively from 5.2 m in the west to 2.0 m in the east, reflecting the progressive change of kinematic style from pure left-lateral strike-slip faulting to left-lateral-reverse faulting. Along the three western segments, we measure cumulative displacements that are multiples of the 1957 coseismic offset, which may be consistent with a characteristic slip. Moreover, using these data, we re-estimate the moment magnitude of the Gobi-Altay earthquake at M-w 7.78-7.95.;Combining our slip rate estimates and the slip distribution per event we also determined a mean recurrence interval of similar to 2500-5200 yr for past earthquakes along the different segments of the western Bogd Fault. This suggests that the three western segments of the Bogd Fault and the Gurvan Bulag thrust fault (a reverse fault bounding the southern side of the Ih Bogd range that ruptured during the 1957 earthquake) have similar average recurrence times, and therefore may have ruptured together in previous earthquakes as they did in 1957. These results suggest that the western part of the Bogd Fault system, including the Gurvan Bulag thrust fault, usually behaves in a 'characteristic earthquake' mode.
ISSN: 0956-540X

hal-00639467
https://hal.archives-ouvertes.fr/hal-00639467
https://hal.archives-ouvertes.fr/hal-00639467v2/document
https://hal.archives-ouvertes.fr/hal-00639467/file/rizzaGJI2011.pdf
DOI : 10.1111/j.1365-246X.2011.05075.x

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
Introduction: Most studies on nematode-malaria interactions were conducted outside of the Americas. The objective of the present study was thus to study the relation between malaria and nematodes in a cohort of children in an Amazonian village. Methods: Odds ratios for intestinal nematode infections as an explanatory variable to malaria resistant vs. malaria sensitive were computed. Results: Ascaris lumbricoides was significantly more frequent in the ‘resistant’ malaria group than in the ‘sensitive’ one. Conclusions: Despite its low statistical power, the present results find that Ascaris was associated with less malaria, as observed by a number of studies.
ISSN: 0142-6338

inserm-01410100
http://www.hal.inserm.fr/inserm-01410100
http://www.hal.inserm.fr/inserm-01410100/document
http://www.hal.inserm.fr/inserm-01410100/file/worms%20malaria%20camopi%20j%20trop%20pediatrics.pdf
http://www.hal.inserm.fr/inserm-01410100/file/GI%20nematodes%20tab%20aurelia%29.pdf