Did high Neo-Tethys subduction rates contribute to early Cenozoic warming?

International audienceThe 58–51 Ma interval was characterized by a long-term increase of global temperatures (+4 to +6 • C) up to the Early Eocene Climate Optimum (EECO, 52.9– 50.7 Ma), the warmest interval of the Cenozoic. It was recently suggested that sustained high atmospheric pCO 2 , controlling warm early Cenozoic climate, may have been released during Neo-Tethys closure through the subduction of large amounts of pelagic carbonates and their recycling as CO 2 at arc volcanoes. To analyze the impact of Neo-Tethys closure on early Cenozoic warming, we have mod-eled the volume of subducted sediments and the amount of CO 2 emitted along the northern Tethys margin. The impact of calculated CO 2 fluxes on global temperature during the early Cenozoic have then been tested using a climate carbon cycle model (GEOCLIM). We show that CO 2 production may have reached up to 1.55 × 10 18 mol Ma −1 specifically during the EECO, ∼ 4 to 37 % higher that the modern global volcanic CO 2 output, owing to a dramatic India-Asia plate convergence increase. The subduction of thick Greater Indian continental margin carbonate sediments at ∼ 55–50 Ma may also have led to additional CO 2 production of 3.35 × 10 18 mol Ma −1 during the EECO, making a total of 85 % of the global volcanic CO 2 outgassed. However , climate modeling demonstrates that timing of maximum CO 2 release only partially fits with the EECO, and that corresponding maximum pCO 2 values (750 ppm) and surface warming (+2 • C) do not reach values inferred from geo-chemical proxies, a result consistent with conclusions arising from modeling based on other published CO 2 fluxes. These results demonstrate that CO 2 derived from decarbonation of Neo-Tethyan lithosphere may have possibly contributed to, but certainly cannot account alone for early Cenozoic warming. Other commonly cited sources of excess CO 2 such as enhanced igneous province volcanism also appear to be up to 1 order of magnitude below fluxes required by the model to fit with proxy data of pCO 2 and temperature at that time. An alternate explanation may be that CO 2 consumption, a key parameter of the long-term atmospheric pCO 2 balance, may have been lower than suggested by modeling. These results call for a better calibration of early Cenozoic weathering rates

Divergent Routing of Positive and Negative Information from the Amygdala during Memory Retrieval

Although the basolateral amygdala (BLA) is known to play a critical role in the formation of memories of both positive and negative valence, the coding and routing of valence-related information is poorly understood. Here, we recorded BLA neurons during the retrieval of associative memories and used optogenetic-mediated phototagging to identify populations of neurons that synapse in the nucleus accumbens (NAc), the central amygdala (CeA), or ventral hippocampus (vHPC). We found that despite heterogeneous neural responses within each population, the proportions of BLA-NAc neurons excited by reward predictive cues and of BLA-CeA neurons excited by aversion predictive cues were higher than within the entire BLA. Although the BLA-vHPC projection is known to drive behaviors of innate negative valence, these neurons did not preferentially code for learned negative valence. Together, these findings suggest that valence encoding in the BLA is at least partially mediated via divergent activity of anatomically defined neural populations.National Institute of Mental Health (U.S.) (Grant R01-MH102441-01)National Institutes of Health (U.S.) (Grant DP2-DK-102256-01

Response of littoral chironomid community and organic matter to late glacial lake level and environmental changes at Lago dell'Accesa (Tuscany, Italy).

International audienceThis study focuses on the response of lacustrine littoral chironomid communities to late glacial changes in limnological, environmental and climate conditions in the Mediterranean context. Late glacial chironomid (Diptera: Chironomidae) assemblages, organic petrography and geochemistry were analysed in a sediment core from the littoral zone of Lago dell'Accesa (Tuscany, Italy), where the lake-level fluctuations and the vegetation history have been previously reconstructed. Comparison of the chironomid stratigraphy to other proxies (pollen assemblages, organic petrography and geochemistry, lake-level) and regional climate reconstruction suggested the predominant influence of lake-level changes on the littoral chironomid fauna. The main lowering events that occurred during the Oldest and the Younger Dryas were followed by higher proportions of taxa typical of littoral habitats. A complementary study of organic matter suggested the indirect impact of lake-level on the chironomids through changes in humic status and habitat characteristics, such as the type of substrate and aquatic macrophyte development. Several chironomid taxa, such as Glyptotendipes, Microtendipes and Cricotopus type patens, were identified as possible indicators of low lake-level in the late glacial records. Nevertheless, this study suggested that parallel analyses of organic matter and chironomid assemblages may be needed to circumvent misinterpretation of littoral chironomid assemblage stratigraphy. There was a weak response of the chironomid assemblages to small lake-level lowerings that corresponded to the Older Dryas and Preboreal oscillations. A higher level of determination, e.g. to the species group level, may be necessary to increase the sensibility of the indicators to lake-level changes

Multiple Redox Modes in the Reversible Lithiation of High-Capacity, Peierls-Distorted Vanadium Sulfide.

This is the author accepted manuscript. The final version is available from ACS via http://dx.doi.org/10.1021/jacs.5b03395Vanadium sulfide VS4 in the patronite mineral structure is a linear chain compound comprising vanadium atoms coordinated by disulfide anions [S2](2-). (51)V NMR shows that the material, despite having V formally in the d(1) configuration, is diamagnetic, suggesting potential dimerization through metal-metal bonding associated with a Peierls distortion of the linear chains. This is supported by density functional calculations, and is also consistent with the observed alternation in V-V distances of 2.8 and 3.2 Å along the chains. Partial lithiation results in reduction of the disulfide ions to sulfide S(2-), via an internal redox process whereby an electron from V(4+) is transferred to [S2](2-) resulting in oxidation of V(4+) to V(5+) and reduction of the [S2](2-) to S(2-) to form Li3VS4 containing tetrahedral [VS4](3-) anions. On further lithiation this is followed by reduction of the V(5+) in Li3VS4 to form Li3+xVS4 (x = 0.5-1), a mixed valent V(4+)/V(5+) compound. Eventually reduction to Li2S plus elemental V occurs. Despite the complex redox processes involving both the cation and the anion occurring in this material, the system is found to be partially reversible between 0 and 3 V. The unusual redox processes in this system are elucidated using a suite of short-range characterization tools including (51)V nuclear magnetic resonance spectroscopy (NMR), S K-edge X-ray absorption near edge spectroscopy (XANES), and pair distribution function (PDF) analysis of X-ray data.SB acknowledges Schlumberger Stichting Fund and European Research Council (EU ERC) for funding. JC thanks BK21 plus project of Korea. We thank Phoebe Allan and Andrew J. Morris, University of Cambridge, for useful discussions. We also thank Trudy Bolin and Tianpin Wu of Beamline 9-BM, Argonne National Laboratory for help with XANES measurements. The DFT calculations were performed at the UCSB Center for Scientific Computing at UC Santa Barbara, supported by the California Nanosystems Institute (NSF CNS-0960316), Hewlett-Packard, and the Materials Research Laboratory (DMR-1121053). This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357

Absorption des acides aminés au niveau du rumen de l’intestin grêle et du caecum chez le mouton

Demaux G., Le Bars Henri, Mollé J., Rérat Alain, Simonnet Henri. Absorption des acides aminés, au niveau du rumen, de l’intestin grêle et du cæcum chez le Mouton. In: Bulletin de l'Académie Vétérinaire de France tome 114 n°2, 1961. pp. 85-88

Current genetic admixture between relictual populations might enhance the recovery of an elusive carnivore

The present study investigated the natural recovery of the Eurasian otter (Lutra lutra) in France. The otter was widely distributed in France at the dawn of the 20th century, but then its range considerably shrank and became highly fragmented until the early 1970s, just before it was legally protected. However, for more than 25 years, the otter has been reconquering several parts of its original range and is now considered to be in expansion in France. We investigated the genetic differentiation and diversity of several populations from western and central France and northern Spain to gain insight into the recolonisation dynamics of this elusive species. The present study, based on the use of 14 microsatellite markers, revealed that otter populations seem to be split into five distinct groups. The distribution of samples in those five clusters was closely correlated with suspected refugia where the otter probably survived during the 20th century. Admixture was observed between genetic lineages, possibly enhancing their genetic diversity and thus increasing the recolonisation dynamics of these populations. This phenomenon resembles the genetic pattern noted in many invasive exotic species derived from multiple sources and introduction events. Finally, a demographic approach revealed the probable link between historical human pressure and otter population fragmentation patterns

Changes in ecosystems, climate and societies in the Jura Mountains between 40 and 8 ka cal BP

International audienceWe present radiometric, palaeoclimatological, palaeoenvironmental and archaeological data for the period 40 000–8000 cal BP in the Jura Mountains (eastern France). These mountains culminate at ∼1700 m a.s.l. and are today characterised by a semi-continental climate. During the Last Glacial Maximum, the range supported a local ice cap. While recent data suggest a possible early ice-cap development during MIS 4, the chronology of the regional LGM and following deglaciation has still to be refined. The complete disappearance of the local ice cap at ca 17 000–16 600 cal BP marked the beginning of accumulation of sediment archives in the Jurassian lakes and mires, which favoured the reconstruction of past changes in climatic and environmental conditions, in addition to faunal remains found in caves and in archaeological sites. Three main successive stages may be distinguished regarding the history of societies. The first stage at ca 40 000–18 700 cal BP was characterized by very few archaeological sites with only discontinuous intermittent occupations, always located outside the Jura range. The second stage, around 18 700–11 700 cal BP, corresponded to an increase in the population density, as suggested by an increasing number of archaeological sites and a progressive colonisation of elevated areas of the Jura Mountains. The third stage at ca 11 700–8000 cal BP coincided with a reinforcement of settlement in the lowland areas as well as a development of long-term occupations in elevated areas. The millennial-scale GS-1 cold event had a more long-lasting and stronger impact on societies than did the 200 year-long 8.2 ka cold event

Projet de conservation de la biodiversité dans la moyenne vallée du Zambèze après éradication de la mouche tsé-tsé (Zimbabwé). Etude de faisabilité d'un microprojet : le ranch communal de gibier de Gonono (Gonono communal game ranch)

Le "ranch communal de gibier de Gonono" s'inscrit dans le cadre des micro-projets proposés de manière consensuelle au Comité exécutif du "Projet de Conservation de la Biodiversité dans la Moyenne Vallée du Zambèze après l'Eradication. de la Mouche Tsé-tsé". Dans le but global d'améliorer durablement les conditions de vie de la population du Ward de Gonono, l'objectif spécifique de ce micro-projet est de mettre au point un mode local de production alternative de viande à bas prix à partir de la faune sauvage. Décidé et conçu avec les autorités du Ward, le ranch doit être progressivement géré par et pour la population du Ward. Il doit d'abord produire sur place une viande de gibier recherchée par les communautés locales qui n'y avaient accès jusqu'à présent que de manière illégale. Cette viande doit être produite à un coût modéré accessible à la population. Le ranch doit aussi permettre de conserver un espace étendu encore faiblement anthropisé en le valorisant par des productions à faible impact écologique. En phase de croisière, l'exploitation sur 3.000 hectares du peuplement multispécifique de gibier devrait permettre la fourniture annuelle de 3 0 tonnes carcasse de viande d'impala et 10. tonnes carcasse de viande d'autres espèces, soit une productivité de 13 kg carcasse de venaison par hectare. Quelques productions annexes sont aussi prévues. L'objectif économique est la couverture du prix de revient de la viande et non pas la recherche d'un profit financier. La création de ce ranch communal de gibier est une entreprise à caractère hautement innovant aux plans institutionnel et technique. Il doit donc être considéré comme une opération pilote à part entière et, à ce titre, doit pouvoir bénéficier d'un encadrement serré et d'un appui scientifique conséquent, tout au moins les premières années. (Résumé d'auteur

Association of decreased mitochondrial DNA content with ovarian cancer progression

Mitochondrial DNA (mtDNA) content in ovarian carcinomas was assessed by quantitative PCR. Results show that mtDNA content in tumour cell was significantly higher than that in normal ovary. Change in mtDNA content was not related with patients' age or tumour stages. However, the average mtDNA copy number in pathological low-grade tumours was over two-fold higher than that in high-grade carcinomas (P=0.012). Moreover, type I carcinomas also had a significantly higher mtDNA copy number than in type II carcinomas (P=0.019). Change in mtDNA content might be an important genetic event in the progression of ovarian carcinomas