Éditeur(s) : Baltimore : John Hopkins
Extrait de : Johns Hopkins University studies in historical and political science

Provenance : Université Caen Normandie. Service commun de la documentation
Permalien : http://www.manioc.org/patrimon/CAE19069
CAE19069

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : In this paper we present the potential of a new compact superconducting gravimeter (GWR iGrav) designed for groundwater monitoring. At first, 3 yr of continuous gravity data are evaluated and the performance of the instrument is investigated. With repeated absolute gravity measurements using a Micro-g Lacoste FG5, the calibration factor (−894.8 nm s−2 V−1) and the long-term drift of this instrument (45 nm s−2 yr−1) are estimated for the first time with a high precision and found to be respectively constant and linear for this particular iGrav. The low noise level performance is found similar to those of previous superconducting gravimeters and leads to gravity residuals coherent with local hydrology. The iGrav is located in a fully instrumented hydrogeophysical observatory on the Durzon karstic basin (Larzac plateau, south of France). Rain gauges and a flux tower (evapo-transpiration measurements) are used to evaluate the groundwater mass balance at the local scale. Water mass balance demonstrates that the karst is only capacitive: all the rainwater is temporarily stored in the matrix and fast transfers to the spring through fractures are insignificant in this area. Moreover, the upper part of the karst around the observatory appears to be representative of slow transfer of the whole catchment. Indeed, slow transfer estimated on the site fully supports the low-flow discharge at the only spring which represents all groundwater outflows from the catchment. In the last part of the paper, reservoir models are used to characterize the water transfer and storage processes. Particular highlights are done on the advantages of continuous gravity data (compared to repeated campaigns) and on the importance of local accurate meteorological data to limit misinterpretation of the gravity observations. The results are complementary with previous studies at the basin scale and show a clear potential for continuous gravity time-series assimilation in hydrological simulations, even on heterogeneous karstic systems.
ISSN: 0956-540X

hal-01526965
https://hal.archives-ouvertes.fr/hal-01526965
https://hal.archives-ouvertes.fr/hal-01526965/document
https://hal.archives-ouvertes.fr/hal-01526965/file/fores2016.pdf
DOI : 10.1093/gji/ggw396

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
Persistent organic pollutants have not been conclusively associated with length of gestation or with preterm birth. Chlordecone is an organochlorine pesticide that has been extensively used to control the banana root borer population in the French West Indies. Data from the Timoun Mother-Child Cohort Study conducted in Guadeloupe between 2004 and 2007 were used to examine the associations of chlordecone concentrations in maternal plasma with the length of gestation and the rate preterm birth in 818 pregnant women. Data were analyzed using multivariate linear regression for length of gestation and a Cox model for preterm birth. The median plasma chlordecone concentration was 0.39 µg/L (interquartile range, 0.18-0.83). No correlation was observed with plasma concentrations of p,p'-dichlorodiphenyl dichloroethene (ρ = 0.017) or polychlorinated biphenyl 153 (ρ = -0.016), the other main organochlorine compounds detected. A 1-log10 increase in chlordecone concentration was associated with a decreased length of gestation (-0.27 weeks; 95% confidence interval: -0.50, -0.03) and an increased risk of preterm birth (60%; 95% confidence interval: 10, 130). These associations may result from the estrogen-like and progestin-like properties of chlordecone. These results are of public health relevance because of the prolonged persistence of chlordecone in the environment and the high background rate of preterm births in this population.
ISSN: 0002-9262

hal-01010740
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01010740
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01010740/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01010740/file/Chlordecone%20Exposure%20final.pdf
DOI : 10.1093/aje/kwt313

Éditeur(s) : London : Hamilton, Adams & Co
Siècle(s) traité(s) : 19
Droits : Domaine public
Provenance : Ville de Pointe-à-Pitre. Réseau des bibliothèques
Permalien : http://www.manioc.org/patrimon/HASH0103f0f83da4829c83c1b88d
HASH0103f0f83da4829c83c1b88d

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
STUDY QUESTION: Do mild analgesics affect the endocrine system of the human adult testis? SUMMARY ANSWER: Mild analgesics induce multiple endocrine disturbances in the human adult testis in vitro. WHAT IS KNOWN ALREADY: Mild analgesics have recently been incriminated as potential endocrine disruptors. Studies of the effects of these widely used molecules on the androgenic status of men are limited and somewhat contradictory. This prompted us to investigate whether these compounds could alter the adult human testicular function. We therefore assessed in parallel the effects of paracetamol, aspirin and indomethacin on organo-cultured adult human testis and on the NCI-H295R steroid-producing human cell line. STUDY DESIGN, SIZE, DURATION: Adult human testis explants or NCI-H295R adrenocortical human cells were cultured with 10(-4) or 10(-5) M paracetamol, aspirin or indomethacin for 24-48 h. The effect of 10(-5) M ketoconazole, used as an anti-androgenic reference molecule, was also assessed. PARTICIPANTS/MATERIALS, SETTING, METHODS: Testes were obtained from prostate cancer patients, who had not received any hormone therapy. The protocol was approved by the local ethics committee of Rennes, France and informed consent was given by the donors. Only testes displaying spermatogenesis, as assessed by transillumination, were used in this study. Hormone levels in the culture media were determined by radioimmunoassay (testosterone, insulin-like factor 3), Enzyme-Linked Immunosorbent Assay (inhibin B) or Enzyme Immunosorbent Assay [prostaglandin (PG) D2, and PGE2]. Tissues were observed and cells counted using classical immunohistochemical methods. MAIN RESULTS AND THE ROLE OF CHANCE: The three mild analgesics caused multiple endocrine disturbances in the adult human testis. This was particularly apparent in the interstitial compartment. Effective doses were in the same range as those measured in blood plasma following standard analgesic treatment. The production of testosterone and insulin-like factor 3 by Leydig cells was altered by exposure to all these drugs. Inhibin B production by Sertoli cells was marginally affected by aspirin only. Our experiments also revealed that mild analgesics display direct anti-PG activity, which varied depending on the drug used, the dose and the duration of exposure. Nevertheless, associations between the alteration of the PG and testosterone profiles were not systematically observed, suggesting that a combination of mechanisms of endocrine disruption is at play. LIMITATIONS, REASONS FOR CAUTION: Our studies were performed in vitro. WIDER IMPLICATIONS OF THE FINDINGS: We provide the first evidence that direct exposure to mild analgesics can result in multiple endocrine disturbances in the human adult testis. Caution, concerning the consumption of mild analgesics by men, should be strengthened, particularly in high-risk population subgroups such as elite athletes.
ISSN: 0268-1161

inserm-00866016
http://www.hal.inserm.fr/inserm-00866016
PUBMED : 23670170
DOI : 10.1093/humrep/det112

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
OBJECTIVES: To better select for patients who most likely will benefit from cardiac surgery among those with infective endocarditis (IE), we aimed to identify preoperative markers associated with poor outcome after cardiac surgery for IE, and to evaluate the accuracy of European System for Cardiac Operative Risk Evaluation (EuroSCORE) II to predict mortality. METHODS: We enrolled all adult patients who underwent cardiac surgery during the acute phase of definite IE (Duke Criteria) in two referral centres for cardiac surgery. Patients were identified through intensive care unit (ICU) electronic databases, and data were collected from medical charts on standardized questionnaire. RESULTS: Between 2002 and 2013, 149 patients (117 males), with a median age of 64 years [interquartile range 52-73], fulfilled the inclusion criteria. Main complications before surgery were left ventricular dysfunction (23%), central nervous system symptomatic events (34%) and septic shock (24%). Most patients (95%) presented with valve regurgitation, and 49% had perivalvular abscess. Surgery was performed with a median delay of 12 days [5-24] after IE diagnosis, and mean EuroSCORE II was 15.8 (13.4-18.1). In-hospital mortality was 21%. Preoperative variables associated with mortality in multivariate analysis were obesity [odds ratio (OR) 3.67 [1.10-12.19], P = 0.03], vegetation extgreater15 mm (OR 6.72 [1.46-30.98], P = 0.01), septic shock (OR 4.87 [1.67-14.28], P = 0.004) and mechanical prosthetic valve IE (OR 4.99 [1.72-28.57], P = 0.007). EuroSCORE II underestimated mortality in patients with predicted mortality over 10%. CONCLUSION: Factors independently predictive of mortality after cardiac surgery for IE are obesity, septic shock, large vegetation and a mechanical prosthetic valve IE. EuroSCORE II underestimates post-cardiac surgery mortality in patients with IE
ISSN: 1010-7940

hal-01169802
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01169802
DOI : 10.1093/ejcts/ezv223
PUBMED : 26116921

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
IODP Expedition 324 cored igneous rocks from Shatsky Rise, an oceanic plateau in the northwest Pacific Ocean that formed mainly during late Jurassic and Early Cretaceous times. We selected 60 samples from 3 different holes for Thellier-Thellier palaeointensity determinations. Induced and remanent magnetization curves measured at low- and high-temperature suggest a diverse and complex magnetic mineralogy, with large variations in Ti content and oxidation state. Hysteresis and FORC measurements show that most samples contain singledomain magnetic grains. After carrying out the palaeointensity determinations, only 9 samples satisfied all reliability criteria. These gave palaeointensity values between 16.5 and 21.5 μT, which correspond to average VDM values of (4.9 ± 0.2) × 1022 Am2 for an estimated age of 140-142 Ma. This value is lower than that for the recent field, which agrees with the hypothesis of a Mesozoic Dipole Low.
ISSN: 0956-540X

hal-00795491
https://hal.archives-ouvertes.fr/hal-00795491
DOI : 10.1093/gji/ggs100

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
Functional ecology has long considered the support function as important, but its biomechanical complexity is only just being elucidated. We show here that it can be described on the basis of four biomechanical traits, two safety traits against winds (SW) and self-buckling (SB), and two motricity traits involved in sustaining an upright position, tropic motion velocity (MV) and posture control (PC). All these traits are integrated at the tree scale, combining tree size and shape together with wood properties. The assumption of trait constancy has been used to derive allometric scaling laws, but it was more recently found that observing their variations among environments and functional groups, or during ontogeny, provides more insights into adaptive syndromes of tree shape and wood properties. However, over-simplified expressions have often been used, possibly concealing key adaptive drivers. An extreme case of over-simplification is the use of wood basic density as a proxy for safety. Actually, since wood density is involved in stiffness, loads and construction costs, the impact of its variations on safety is non-trivial. Moreover, other wood features, especially the microfibril angle (MFA), are also involved. Furthermore, wood is not only stiff and strong, but it also acts as a motor for MV and PC. The relevant wood trait for that is maturation strain asymmetry. Maturation strains vary with cell wall characteristics such as MFA, rather than with wood density. Finally, the need for further studies about the ecological relevance of branching patterns, motricity traits and growth responses to mechanical loads is discussed.
ISSN: 0022-0957

hal-00909904
https://hal.archives-ouvertes.fr/hal-00909904
https://hal.archives-ouvertes.fr/hal-00909904/document
https://hal.archives-ouvertes.fr/hal-00909904/file/Integrative_biomechanics_for_tree_Fournier_al.pdf
DOI : 10.1093/jxb/ert279

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
The southwestern Tianshan (China) metamorphic belt records high-pressure (HP) to ultrahigh-pressure (UHP) conditions corresponding to a cold oceanic subduction-zone setting. Serpentinites enclosing retrogressed eclogite and rodingite occur as lenses within metapelites in the UHP unit, which also hosts coesite-bearing eclogites. Based on the petrology and petrography of these serpentinites, five events are recognized: (1) formation of a wehrlite–harzburgite–dunite association in the mantle; (2) retrograde metamorphism and partial hydration during exhumation of the mantle rocks close to the seafloor; (3) oceanic metamorphism leading to the first serpentinization and rodingitization; (4) UHP metamorphism during subduction; (5) retrograde metamorphism during exhumation together with a second serpentinization. The peak metamorphic mineral assemblage of the serpentinized wehrlite comprises Ti-chondrodite + olivine + antigorite + chlorite + magnetite + brucite. A computed pseudosection for this serpentinized wehrlite shows that the Al content in antigorite is mostly sensititive to temperature but can also be used to constrain pressure. The average XAl = 0·204 ± 0·026 of antigorite (XAl = Al (a.p.f.u.)/8, where Al is in atoms per formula unit for a structural formula M48T34O85(OH)62, and M and T are octahedral and tetrahedral sites, respectively) included in Ti-chondrodite and average XAl = 0·203 ± 0·019 of antigorite in the matrix result in a well-constrained peak metamorphic temperature of 510–530°C. Peak pressures are less precisely constrained at 37 ± 7 kbar. The Tianshan serpentinites thus record UHP metamorphic conditions and represent the deepest subducted serpentinites discovered so far. The retrograde evolution occurs within the stability field of brucite + antigorite + olivine + chlorite and formation of Ti-clinohumite at the expense of Ti-chondrodite has been observed, suggesting isothermal decompression. The resulting P–T path is in excellent agreement with the metamorphic evolution of country rocks, indicating that the UHP unit in Tianshan was subducted and exhumed as a coherent block. To refine the metamorphic path of the ultramafic rocks, we have investigated the stability fields of Ti-chondrodite and Ti-clinohumite using piston-cylinder experiments. A total of 11 experiments were conducted at 25–55 kbar and 600–750°C in a F-free natural system. Combined with previous experiments and information from natural rocks we constructed a petrogenetic grid for the stability of Ti-chondrodite and Ti-clinohumite in F-free peridotite compositions. The formation of Ti-chondrodite in serpentinites requires a minimum pressure of about 26 kbar, whereas in Ti-rich systems it can form at considerably lower pressures. A key finding is that at UHP conditions, F-free Ti-chondrodite or Ti-clinohumite breaks down in the presence of orthopyroxene between 700 and 750°C, at temperatures that are significantly lower than those of the terminal breakdown reactions of these humite minerals. These breakdown reactions are an additional source of fluid during prograde subduction of serpentinites.
ISSN: 0022-3530

hal-01243507
https://hal.archives-ouvertes.fr/hal-01243507
DOI : 10.1093/petrology/egv042

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
OBJECTIVES: To compare virological effectiveness in patients who continued on a virologically successful first-line boosted protease inhibitor (PI)-containing combination antiretroviral therapy (cART) regimen or who switched to a PI-free cART including efavirenz, nevirapine or abacavir. METHODS: From the French Hospital Database on HIV, we selected 439 patients with undetectable viral load (VL) on a first-line boosted PI-containing cART regimen who switched to a PI-free combination including efavirenz, nevirapine or abacavir. Each of these patients was matched with three patients who continued to take their first-line cART regimen, on the basis of gender, age, CD4 cell count, VL, date of cART initiation and the duration of VL undetectability. Time to virological failure (VF) was analysed with Kaplan-Meier curves and Cox models. RESULTS: The 12 month probabilities of VF were 3.7% and 5.7% in non-switch and switch patients, respectively, and 3.9%, 7.2% and 9.0% in patients switching to efavirenz-, nevirapine- and abacavir-containing cART, respectively. After adjustment, only patients switching to abacavir-containing cART had a higher risk of VF than non-switch patients (adjusted hazard ratio, 1.99; 95% confidence interval, 1.05-3.79). CONCLUSIONS: Switching from a virologically successful first-line boosted PI-containing cART regimen to a non-nucleoside reverse transcriptase inhibitor-containing cART regimen containing either efavirenz or nevirapine is virologically safe, while switching to abacavir-containing cART should be avoided.
ISSN: 0305-7453

hal-00875284
https://hal.archives-ouvertes.fr/hal-00875284
DOI : 10.1093/jac/dkr208
PUBMED : 21636583

Éditeur(s) : HAL CCSD Elsevier
Résumé : Among the radionuclides that can migrate from radioactive wastes buried within consolidated argillaceous rocks, I-129 poses a particular problem due to its high mobility in geomedia and its very long half-life of 1.6 10(7) years. Previous studies carried out on such rocks showed the existence of a low iodide retardation regarding the other anion species. The purpose of the present study was two-fold. It was hoped (1) to confirm this retardation by means of radial diffusion experiments and (2) to estimate the influence of the initial iodide concentrations towards the iodide uptake. The results obtained from in-diffusion stage show that (1) no iodide uptake occurs at high initial concentrations and (2) an uptake at low initial concentrations cannot be clearly evidenced. Finally. the most singular behaviour of iodide was highlighted for all the initial iodide concentrations, from the out-diffusion stage. during which some amount of iodide, available for out-diffusion, were not involved in the diffusion process. Although the origin of such phenomenon remains unclear, a kinetic effect for the iodide uptake was proposed, assuming that the period of 55days (corresponding to the in-diffusion stage duration) would be necessary for inducing the iodide uptake. This kinetic effect, already shown elsewhere by (Descostes. M., Blin, V., Bazer-Bachi, F., Meier, P., Grenut, B., Radwan. J., Schlegel, M.L., Buschaert, S.. Coelho, D, Tevissen, E. Diffusion of anionic species in Callovo-Oxfordian argillites and Oxfordian limestones. In press for Appl. Geochem.) on similar materials, needs to be deepened.
ISSN: 0079-1946

hal-00412393
https://hal.archives-ouvertes.fr/hal-00412393
DOI : 10.1016/j.pce.2008.05.020

Éditeur(s) : HAL CCSD Oxford University Press (OUP): Policy B - Oxford Open Option B
Résumé : Variability of leaf traits related to photosynthesis was assessed in seedlings from 14 tree species growing in the tropical rain forest of French Guiana. Leaf photosynthetic capacity (maximum rate of carboxylation and maximum rate of electron transport) was estimated by fitting a biochemical model of photosynthesis to response curves of net CO2 assimilation rate versus intercellular CO2 mole fraction. Leaf morphology described by leaf mass per unit leaf area (LMA), density and thickness, as well as area- and mass-based nitrogen (N) and carbon (C) concentrations, were recorded on the same leaves. Large interspecific variability was detected in photosynthetic capacity as well as in leaf structure and leaf N and C concentrations. No correlation was found between leaf thickness and density. The correlations between area- and massbased leaf N concentration and photosynthetic capacity were poor. Conversely, the species differed greatly in relativeNallocation to carboxylation and bioenergetics. Principal component analysis (PCA) revealed that, of the recorded traits, only the computed fraction of total leafNinvested in photosynthesis was tightly correlated to photosynthetic capacity.We also used PCAto test to what extent species with similar shade tolerances displayed converging leaf traits related to photosynthesis. No clear-cut ranking could be detected among the shade-tolerant groups, as confirmed by a one-way ANOVA.We conclude that the large interspecific diversity in photosynthetic capacity was mostly explained by differences in the relative allocation of N to photosynthesis and not by leafNconcentration, and that leaf traits related to photosynthetic capacity did not discriminate shade-tolerance ranking of these tropical tree species.
ISSN: 0829-318X

hal-01031522
https://hal.archives-ouvertes.fr/hal-01031522

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
STUDY QUESTION: Is there evidence at the population level of associations between different male genital disorders, outside Scandinavian countries? SUMMARY ANSWER: At an international scale, there is evidence for a number of correlations between rates of four male reproductive disorders (hypospadias, cryptorchidism, testicular cancer and low sperm concentration). WHAT IS KNOWN ALREADY: Some associations between these outcomes have been shown in studies focusing on individuals and mainly in Nordic European countries. These associations, together with histological evidence of a dysgenesis pattern in testicular tissue specimens, have generated the concept of the existence of a 'testicular dysgenesis syndrome' originating in utero. STUDY DESIGN, SIZE, DURATION: This is a geographical correlation study using cancer, malformations rates and sperm quality data collected between the years 1998 and 2005. PARTICIPANTS/MATERIALS, SETTING, METHODS: Incidence rates of testicular cancer were extracted from International Agency for Research on Cancer registries and Globocan, while cryptorchidism and hypospadias prevalence rates were obtained from EUROCAT and International Clearinghouse for Birth Defects Surveillance and Research registries. Sperm concentration data were extracted from recent studies using standardized methodology. A total of 39 registries and 9 sperm studies were selected. Non-parametric Spearman correlation tests were used to test the association between these four disorders. Correlations were computed for all registries together, for registries with high-quality matching coverage only and by continents. Sensitivity analyses were also conducted using data from prospective clinical studies to take into account potential bias related mainly to ascertainment of malformation rates. MAIN RESULTS AND THE ROLE OF CHANCE: We found positive correlations between testicular cancer and hypospadias (r = 0.32, P = 0.05) and between hypospadias and cryptorchidism (r = 0.70, P = 0.008). Stronger correlations were observed when using registries with high-quality matching coverage. Among these registries, differences between Europe and the rest of the world appeared (the positive correlation between testicular cancer and cryptorchidism was stronger outside Europe, r = 0.83, P = 0.01 compared with 0.40, P = 0.60 for European registries). A negative correlation between testicular cancer and sperm concentration was observed (r = -0.88, P = 0.002). These correlations support our initial hypothesis but remain only suggestive due to the intrinsic limitations in the study design (i.e. geographical correlation study) and do not allow causal inference. LIMITATIONS, REASONS FOR CAUTION: Differences in the ascertainment of malformations rates (definition, length of follow-up) make the international comparison difficult. The small number of registries for some conditions (cryptorchidism) or of studies (for sperm quality) and the absence of information about major risk factors such as ethnicity and socioeconomic status in the registries are also limitations. WIDER IMPLICATIONS OF THE FINDINGS: Our findings are in agreement with results of studies focusing on individuals and suggest that shared risk factors are present in the populations studied.
ISSN: 0268-1161

inserm-00863412
http://www.hal.inserm.fr/inserm-00863412
DOI : 10.1093/humrep/det111
PUBMED : 23670171

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
The Ronda peridotite massif in Southern Spain shows a well-defined 'recrystallization' front that separates a large-scale partial melting domain formed at the expense of the continental lithospheric mantle from a 'preserved' lithospheric domain. To investigate the processes allowing a transient lithosphere-asthenosphere boundary to propagate in the lithospheric mantle, we performed a joint petrostructural and geochemical study of an similar to 2.5 km(2) zone extending from the melting front to the mylonites that mark the western limit of the massif. This study emphasizes a feedback between heat transfer, melt percolation, and deformation in the lithospheric mantle. Petrographical observations and geochemical data show that heterogeneous reactive percolation of melts produced in the underlying partial melting domain led to refertilization of lithospheric peridotites up to 1.5 km ahead from the melting front, producing metre-scale layering of fertile and refractory mantle rocks. Within 800 m from the front, pre-existing garnet pyroxenite layers were partially molten and the resulting melts probably contributed to the refertilization process. Detailed structural mapping and analysis of the microstructures and crystal preferred orientations highlight the relations between reactive melt transport and deformation, and the control of the temperature gradient on both processes. Parallelism between the recrystallization front, compositional boundaries, and deformation structures, as well as variations in the deformation intensity of pyroxenes and spinels, suggest syn- to late-tectonic melt transport controlled by both the deformation and the thermal gradient. Variations in the strength of olivine crystal preferred orientations as a function of the modal and chemical composition of the spinel tectonites point to a higher contribution of diffusion to deformation in the most fertile rocks, corroborating the hypothesis that deformation occurred in presence of melt. Finally, the systematic dispersion of olivine [100] and orthopyroxene [001] axes in the foliation plane suggests a dominantly transpressive deformation regime.
ISSN: 0022-3530

hal-00420904
https://hal.archives-ouvertes.fr/hal-00420904
DOI : 10.1093/petrology/egp032

Éditeur(s) : HAL CCSD Oxford University Press
Résumé : International audience
ISSN: 1369-3786

hal-01118199
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01118199
DOI : 10.3109/13693786.2010.511287
PUBMED : 21067335

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : Geodynamic models incorporating metamorphic phase transformations almost invariably assume the validity of the Boussinesq approximation that violates conservation of mass. In such models metamorphic density changes take place without volumetric effects. We assess the impact of the Boussinesq approximation by comparing models of orogeny accompanied by lower crustal eclogitization both with and without the approximation. Our results demonstrate that the approximation may cause errors approaching 100 per cent in characteristic measures of orogenic shape. Mass conservation errors in Boussinesq models amplify with model time. Mass conservative models of metamorphism are therefore essential to understand long-term tectonic evolution and to assess the importance of the different geodynamic processes.
ISSN: 0956-540X

hal-00617480
https://hal.archives-ouvertes.fr/hal-00617480
DOI : 10.1111/j.1365-246X.2011.05052.x

Éditeur(s) : HAL CCSD Oxford University Press
Résumé : International audience
The epigenetic events imposed during germline reprogramming and affected by harmful exposure can be inherited and transferred to subsequent generations via gametes inheritance. In this study, we examine the transgenerational effects promoted by widely used herbicide atrazine (ATZ). We exposed pregnant outbred CD1 female mice and the male progeny was crossed for three generations with untreated females. We demonstrate here that exposure to ATZ affects meiosis, spermiogenesis and reduces the spermatozoa number in the third generation (F3) male mice. We suggest that changes in testis cell types originate from modified transcriptional network in undifferentiated spermatogonia. Importantly, exposure to ATZ dramatically increases the number of transcripts with novel transcription initiation sites, spliced variants and alternative polyadenylation sites. We found the global decrease in H3K4me3 occupancy in the third generation males. The regions with altered H3K4me3 occupancy in F3 ATZ-derived males correspond to altered H3K4me3 occupancy of F1 generation and 74% of changed peaks in F3 generation are associated with enhancers. The regions with altered H3K4me3 occupancy are enriched in SP family and WT1 transcription factor binding sites. Our data suggest that the embryonic exposure to ATZ affects the development and the changes induced by ATZ are transferred up to three generations.
ISSN: 0305-1048

hal-01477213
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01477213
DOI : 10.1093/nar/gkw840
PUBMED : 27655631

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
To quantify the seismic properties of lower crustal rocks and to better constrain the origin of the lower crustal seismic reflectivity, we determined the complete 3-D seismic properties of a lower crustal section. Eight representative samples of the main lithologic and structural units outcropping in the Val Sesia (Ivrea zone) were studied in detail. The seismic velocities were calculated using the single crystal stiffness coefficients and the lattice preferred orientation (LPO) of each mineral in all samples. The 21 stiffness coefficients characterizing the elastic behaviour of each rock are determined. Mafic and ultramafic rocks such as pyroxenite and pyroxene-bearing gabbros display complex shear wave properties. These rocks are weakly birefringent (maximum 0.1 kms-1) and it is difficult to find consistent relationships between the seismic properties and the rock structure. On the other hand, seismic properties of deformed felsic rocks are essentially controlled by mica. They display strong S-wave birefringence (0.3 km s-1) and relatively high Vp anisotropy (7.6 per cent). Amphibole also strongly influences the rock birefringence patterns. For both kind of rocks, the foliation is highly birefringent and the fast polarized shear wave is systematically oriented parallel to the foliation. We show that the number of mineral phases in the rock strongly controls the anisotropy. The seismic anisotropy has a complex role in the P-wave reflectivity. Compared to the isotropic case, anisotropy enhances the reflection coefficient for about 60 per cent of the possible lithological interfaces. For 40 per cent of the interfaces, the reflection coefficient is much lower when one considers the medium as anisotropic.
ISSN: 0956-540X

hal-01389122
http://hal.univ-reunion.fr/hal-01389122
http://hal.univ-reunion.fr/hal-01389122/document
http://hal.univ-reunion.fr/hal-01389122/file/Barruol_3D_velocities_GJI1993.pdf
DOI : 10.1111/j.1365-246X.1993.tb01519.x

Éditeur(s) : HAL CCSD Oxford University Press
Résumé : International audience
We report on a fatal invasive infection due to the ascomycetous fungus Neocosmospora vasinfecta, in a 20-year-old European patient suffering from an acute lymphoblastic leukemia. The infection could not be controlled by a bitherapy combining liposomal amphotericin B and voriconazole. This is the second case of disseminated infection reported with this unusual fungus, which develops under its teleomorphic state, is fully resistant to all systemic antifungals, and which is known to live in tropical countries.
ISSN: 1369-3786

hal-01101419
https://hal.archives-ouvertes.fr/hal-01101419
PUBMED : 24432214

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé :  
The maintenance in the long run of a positive carbon balance under very low irradiance is a prerequisite for survival of tree seedlings below the canopy or in small gaps in a tropical rainforest. To provide a quantitative basis for this assumption, experiments were carried out to determine whether construction cost (CC) and payback time for leaves and support structures, as well as leaf life span (i) differ among species and (ii) display an irradiance-elicited plasticity. Experiments were also conducted to determine whether leaf life span correlates to CC and payback time and is close to the optimal longevity derived from an optimization model. Saplings from 13 tropical tree species were grown under three levels of irradiance. Specific-CC was computed, as well as CC scaled to leaf area at the metamer level. Photosynthesis was recorded over the leaf life span. Payback time was derived from CC and a simple photosynthesis model. Specific-CC displayed only little interspecific variability and irradiance-elicited plasticity, in contrast to CC scaled to leaf area. Leaf life span ranged from 4 months to >26 months among species, and was longest in seedlings grown under lowest irradiance. It was always much longer than payback time, even under the lowest irradiance. Leaves were shed when their photosynthesis had reached very low values, in contrast to what was predicted by an optimality model. The species ranking for the different traits was stable across irradiance treatments. The two pioneer species always displayed the smallest CC, leaf life span, and payback time. All species displayed a similar large irradiance-elicited plasticity.
ISSN: 0022-0957

hal-01032198
https://hal.archives-ouvertes.fr/hal-01032198
DOI : 10.1093/jxb/err092