207 research outputs found

    Stratigraphy of the Haut Var Paleogene continental series (Northeastern Provence, France): New insight on the age of the 'Sables bleutés du Haut Var' Formation

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    The age of the Paleogene deposits of the Haut Var (Provence, France) has been the subject of debate. Particularly, the ''Calcaire à Bithynies'' and the ''Sables bleutés'' units were ascribed either to the early Eocene or to the Oligocene. A stratigraphical clarification is required in order to precise the paleogeographical relationships of the Haut Var Paleogene sedimentary series with coeval deposits in the neighbouring southern Provence and Subalpine regions and other European domains. The study area is characterized by tectonically separated synclines and grabens filled in by continental Paleogene deposits. Detailed mapping and lithostratigraphical logging, sedimentological and microfacies analysis have been undertaken in order to provide a reliable stratigraphical framework. Biostratigraphical subdivisions were established based on five different fossil groups: mammals, charophytes, gastropods, ostracodes, and foraminifers. Accordingly, five formations are distinguished and dated: ''Calcaire a` Microcodium'' and ''Brèche à Microcodium'' (Danian); ''Marnes à oeufs d'oiseaux'' (Selandian(?)-earliest Ypresian); 'Sables bleutés du Haut Var' (early-late(?) Ypresian); and ''Bourdas conglomerates'' (Rupelian). Particular emphasis is given to the study of the controversial 'Sables bleute´ s du Haut Var' Formation. As a result, correlations have been established between the different syncline and graben areas where Paleocene-Eocene and Oligocene deposits occur. Terrestrial deposits (carbonate paleosols and piedmont alluvial fans) took place during Paleocene times, while fluvial (cross-bedded sands) and lacustrine carbonate deposits developed in a foreland compressional intracontinental basin surrounded by emerged areas and tectonic highs during the early Ypresian. Paleoenvironmental and paleogeo- graphical analysis strengthen the view that a relative isolation characterized the Haut Var area during the early Eocene, probably enhancing episodes of brackish water or evaporitic sedimentation and gastropod endemism. During the late Eocene Pyrenean-Provence tectonic phase, the E-W trending Haut Var overthrusts have been emplaced posteriorly to the deposition of the 'Sables bleute´ s du Haut Var' Fm. Finally, coarse alluvial fan and local lacustrine carbonate sedimentation occurred during the Oligocene in narrow N-S trending subsident extensional grabens associated with the N-S trending Barjols Triassic uplift

    Is the Unitarity of the quark-mixing-CKM-matrix violated in neutron β\beta-decay?

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    We report on a new measurement of neutron β\beta-decay asymmetry. From the result \linebreak A0A_0 = -0.1189(7), we derive the ratio of the axial vector to the vector coupling constant λ\lambda = gA/gV{\it g_A/g_V} = -1.2739(19). When included in the world average for the neutron lifetime τ\tau = 885.7(7)s, this gives the first element of the Cabibbo-Kobayashi-Maskawa (CKM) matrix VudV_{ud} . With this value and the Particle Data Group values for VusV_{us} and VubV_{ub}, we find a deviation from the unitarity condition for the first row of the CKM matrix of Δ\Delta = 0.0083(28), which is 3.0 times the stated error

    Sharpening Low-Energy, Standard-Model Tests via Correlation Coefficients in Neutron Beta-Decay

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    The correlation coefficients a, A, and B in neutron beta-decay are proportional to the ratio of the axial-vector to vector weak coupling constants, g_A/g_V, to leading recoil order. With the advent of the next generation of neutron decay experiments, the recoil-order corrections to these expressions become experimentally accessible, admitting a plurality of Standard Model (SM) tests. The measurement of both a and A, e.g., allows one to test the conserved-vector-current (CVC) hypothesis and to search for second-class currents (SCC) independently. The anticipated precision of these measurements suggests that the bounds on CVC violation and SCC from studies of nuclear beta-decay can be qualitatively bettered. Departures from SM expectations can be interpreted as evidence for non-V-A currents.Comment: 4 pages, REVTeX, intro. broadened, typos fixed, to appear in PR

    Unusually thick dinosaur eggshell fragments from the Spanish Late Cretaceous

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    [EN] Fieldwork carried out recently in the southeastern branch of the Iberian Range (Valencia Province, Spain) has led to the collection of a large volume of dinosaur eggshell fragments of unusual thickness. These specimens, up to 4.9 mm thick, were recovered from palustrine grey marls of the upper Campanian-lower Maastrichtian Sierra Perenchiza Formation, which comprises a wetland paleoenvironment deposit. These eggshell fragments have a characteristic compactituberculate ornamentation, dinosauroid-spherulitic organisation, and exhibit a complex canaliculate respiratory system. The external tuberculate surface of the shell as well as the internal microstructure enable referral to Megaloolithus aff. siruguei, the most common megaloolithid oospecies known from the Iberian Peninsula and southern France. The biostratigraphic range of M. siruguei matches the temporal distribution of titanosaurid dinosaurs across the Iberian Range, tentatively considered to be potential producers.This work was supported by the Ministerio de Economia y Competitividad of Spain [Secretaria de Estado de Investigacion, Desarrollo e Innovacion, projects CGL2013-47521-P and CGL2014-53548-P]Company Rodríguez, J. (2017). Unusually thick dinosaur eggshell fragments from the Spanish Late Cretaceous. Historical Biology (Online). 31(2):203-210. https://doi.org/10.1080/08912963.2017.1357717S203210312Allain, R., & Suberbiola, X. P. (2003). Dinosaurs of France. Comptes Rendus Palevol, 2(1), 27-44. doi:10.1016/s1631-0683(03)00002-2Bravo, A. M., & Gaete, R. (2014). Titanosaur eggshells from the Tremp Formation (Upper Cretaceous, Southern Pyrenees, Spain). Historical Biology, 27(8), 1079-1089. doi:10.1080/08912963.2014.934231Canudo, J. I., Oms, O., Vila, B., Galobart, À., Fondevilla, V., Puértolas-Pascual, E., … Blanco, A. (2016). The upper Maastrichtian dinosaur fossil record from the southern Pyrenees and its contribution to the topic of the Cretaceous–Palaeogene mass extinction event. Cretaceous Research, 57, 540-551. doi:10.1016/j.cretres.2015.06.013Cruzado-Caballero, P., Ruiz-Omeñaca, J. I., Gaete, R., Riera, V., Oms, O., & Canudo, J. I. (2013). A new hadrosaurid dentary from the latest Maastrichtian of the Pyrenees (north Spain) and the high diversity of the duck-billed dinosaurs of the Ibero-Armorican Realm at the very end of the Cretaceous. Historical Biology, 26(5), 619-630. doi:10.1080/08912963.2013.822867Chiappe, L. M., Coria, R. A., Dingus, L., Jackson, F., Chinsamy, A., & Fox, M. (1998). Sauropod dinosaur embryos from the Late Cretaceous of Patagonia. Nature, 396(6708), 258-261. doi:10.1038/24370Company J. 2004. Vertebrados continentales del Cretácico superior (Campaniense-Maastrichtiense) de Valencia [PhD dissertation]. Valencia: Universidad de Valencia.Company, J., & Szentesi, Z. (2012). Amphibians from the Late Cretaceous Sierra Perenchiza Formation of the Chera Basin, Valencia Province, Spain. Cretaceous Research, 37, 240-245. doi:10.1016/j.cretres.2012.04.003Csiki-Sava, Z., Buffetaut, E., Ősi, A., Pereda-Suberbiola, X., & Brusatte, S. L. (2015). Island life in the Cretaceous - faunal composition, biogeography, evolution, and extinction of land-living vertebrates on the Late Cretaceous European archipelago. ZooKeys, 469, 1-161. doi:10.3897/zookeys.469.8439Erben, H. K., Hoefs, J., & Wedepohl, K. H. (1979). Paleobiological and isotopic studies of eggshells from a declining dinosaur species. Paleobiology, 5(4), 380-414. doi:10.1017/s0094837300016900García, R. A. (2007). An «egg-tooth»–like structure in titanosaurian sauropod embryos. Journal of Vertebrate Paleontology, 27(1), 247-252. doi:10.1671/0272-4634(2007)27[247:aesits]2.0.co;2Garcia, G., & Vianey-Liaud, M. (2001). Dinosaur eggshells as biochronological markers in Upper Cretaceous continental deposits. Palaeogeography, Palaeoclimatology, Palaeoecology, 169(1-2), 153-164. doi:10.1016/s0031-0182(01)00215-2Grellet-Tinner, G., Chiappe, L. M., & Coria, R. (2004). Eggs of titanosaurid sauropods from the Upper Cretaceous of Auca Mahuevo (Argentina). Canadian Journal of Earth Sciences, 41(8), 949-960. doi:10.1139/e04-049Grigorescu, D., Garcia, G., Csiki, Z., Codrea, V., & Bojar, A.-V. (2010). Uppermost Cretaceous megaloolithid eggs from the Haţeg Basin, Romania, associated with hadrosaur hatchlings: Search for explanation. Palaeogeography, Palaeoclimatology, Palaeoecology, 293(3-4), 360-374. doi:10.1016/j.palaeo.2010.03.031Izquierdo LA, Montero D, Pérez G, Urién V, Meijide M. 2001. Macroestructura de huevos de dinosaurios en el Cretácico superior de “La Rosaca” (Burgos, España). Actas de las I Jornadas Internacionales Sobre Paleontología de Dinosaurios y su Entorno. Ed. Colectivo Arqueológico y Paleontológico de Salas. Salas de los Infantes. p. 389–395.Jackson FD. 2007. Titanosaur reproductive biology: comparison of the Auca Mahuevo Titanosaur nesting locality (Argentina), to the Pinyes Megaloolithus nesting locality (Spain) [PhD dissertation]. Bozeman (MT): Montana State University.Jackson, F. D., Garrido, A., Schmitt, J. G., Chiappe, L. M., Dingus, L., & Loope, D. B. (2004). Abnormal, multilayered titanosaur (Dinosauria: Sauropoda) eggs from in situ clutches at the Auca Mahuevo locality, Neuquen Province, Argentina. Journal of Vertebrate Paleontology, 24(4), 913-922. doi:10.1671/0272-4634(2004)024[0913:amtdse]2.0.co;2Jackson, F. D., Varricchio, D. J., Jackson, R. A., Vila, B., & Chiappe, L. M. (2008). Comparison of water vapor conductance in a titanosaur egg from the Upper Cretaceous of Argentina and a Megaloolithus siruguei egg from Spain. Paleobiology, 34(2), 229-246. doi:10.1666/0094-8373(2008)034[0229:cowvci]2.0.co;2López-Martı́nez, N., Moratalla, J. J., & Sanz, J. L. (2000). Dinosaurs nesting on tidal flats. Palaeogeography, Palaeoclimatology, Palaeoecology, 160(1-2), 153-163. doi:10.1016/s0031-0182(00)00063-8Mohabey, D. M. (1998). Systematics of Indian Upper Cretaceous dinosaur and chelonian eggshells. Journal of Vertebrate Paleontology, 18(2), 348-362. doi:10.1080/02724634.1998.10011063Moratalla JJ. 1993. Restos indirectos de dinosaurios del registro español: paleoicnología de la Cuenca de (Jurásico superior-Cretácico inferior) y paleoología del Cretácico superior [PhD dissertation]. Madrid: Universidad Autónoma de Madrid.Moreno-Azanza, M., Bauluz, B., Canudo, J. I., Gasca, J. M., & Torcida Fernández-Baldor, F. (2016). Combined Use of Electron and Light Microscopy Techniques Reveals False Secondary Shell Units in Megaloolithidae Eggshells. PLOS ONE, 11(5), e0153026. doi:10.1371/journal.pone.0153026Moreno-Azanza, M., Bauluz, B., Canudo, J. I., Puértolas-Pascual, E., & Sellés, A. G. (2013). A re-evaluation of aff. Megaloolithidae eggshell fragments from the uppermost Cretaceous of the Pyrenees and implications for crocodylomorph eggshell structure. Historical Biology, 26(2), 195-205. doi:10.1080/08912963.2013.786067Oms, O., Dinarès-Turell, J., Vicens, E., Estrada, R., Vila, B., Galobart, À., & Bravo, A. M. (2007). Integrated stratigraphy from the Vallcebre Basin (southeastern Pyrenees, Spain): New insights on the continental Cretaceous−Tertiary transition in southwest Europe. Palaeogeography, Palaeoclimatology, Palaeoecology, 255(1-2), 35-47. doi:10.1016/j.palaeo.2007.02.039Ortega, F., Bardet, N., Barroso-Barcenilla, F., Callapez, P. M., Cambra-Moo, O., Daviero- Gómez, V., … Sanz, J. L. (2015). The biota of the Upper Cretaceous site of «Lo Hueco» (Cuenca, Spain). Journal of Iberian Geology, 41(1). doi:10.5209/rev_jige.2015.v41.n1.48657Rasskin-Gutman, D., Elez, J., Esteve-Altava, B., & López-Martínez, N. (2020). Reconstruction of the internal structure of the pore system of a complex dinosaur eggshell (Megaloolithus siruguei). Spanish Journal of Palaeontology, 28(1), 61. doi:10.7203/sjp.28.1.17831Riera, V., Oms, O., Gaete, R., & Galobart, À. (2009). The end-Cretaceous dinosaur succession in Europe: The Tremp Basin record (Spain). Palaeogeography, Palaeoclimatology, Palaeoecology, 283(3-4), 160-171. doi:10.1016/j.palaeo.2009.09.018Sellés, A. G., Bravo, A. M., Delclòs, X., Colombo, F., Martí, X., Ortega-Blanco, J., … Galobart, À. (2013). Dinosaur eggs in the Upper Cretaceous of the Coll de Nargó area, Lleida Province, south-central Pyrenees, Spain: Oodiversity, biostratigraphy and their implications. Cretaceous Research, 40, 10-20. doi:10.1016/j.cretres.2012.05.004Tanaka, K., & Zelenitsky, D. K. (2014). Comparisons between experimental and morphometric water vapor conductance in the eggs of extant birds and crocodiles: implications for predicting nest type in dinosaurs. Canadian Journal of Zoology, 92(12), 1049-1058. doi:10.1139/cjz-2014-0078Vianey-Liaud, M., Khosla, A., & Garcia, G. (2003). Relationships between European and Indian dinosaur eggs and eggshells of the oofamily Megaloolithidae. Journal of Vertebrate Paleontology, 23(3), 575-585. doi:10.1671/0272-4634(2003)023[0575:rbeaid]2.0.co;2Vianey-Liaud, M., & Lopez-Martinez, N. (1997). Late Cretaceous dinosaur eggshells from the Tremp Basin, southern Pyrenees, Lleida, Spain. Journal of Paleontology, 71(6), 1157-1171. doi:10.1017/s002233600003609xVila, B., Galobart, À., Canudo, J. I., Le Loeuff, J., Dinarès-Turell, J., Riera, V., … Gaete, R. (2012). The diversity of sauropod dinosaurs and their first taxonomic succession from the latest Cretaceous of southwestern Europe: Clues to demise and extinction. Palaeogeography, Palaeoclimatology, Palaeoecology, 350-352, 19-38. doi:10.1016/j.palaeo.2012.06.008(2010). Lethaia, 43(2). doi:10.1111/let.2010.43.issue-2Vila, B., Jackson, F. D., Fortuny, J., Sellés, A. G., & Galobart, À. (2010). 3-D Modelling of Megaloolithid Clutches: Insights about Nest Construction and Dinosaur Behaviour. PLoS ONE, 5(5), e10362. doi:10.1371/journal.pone.0010362Vila, B., Riera, V., Bravo, A. M., Oms, O., Vicens, E., Estrada, R., & Galobart, À. (2011). The chronology of dinosaur oospecies in south-western Europe: Refinements from the Maastrichtian succession of the eastern Pyrenees. Cretaceous Research, 32(3), 378-386. doi:10.1016/j.cretres.2011.01.009Vila, B., Sellés, A. G., & Brusatte, S. L. (2016). Diversity and faunal changes in the latest Cretaceous dinosaur communities of southwestern Europe. Cretaceous Research, 57, 552-564. doi:10.1016/j.cretres.2015.07.003Vissers, R. L. M., & Meijer, P. T. (2012). Iberian plate kinematics and Alpine collision in the Pyrenees. Earth-Science Reviews, 114(1-2), 61-83. doi:10.1016/j.earscirev.2012.05.001Wright, V. P., & Platt, N. H. (1995). Seasonal wetland carbonate sequences and dynamic catenas: a re-appraisal of palustrine limestones. Sedimentary Geology, 99(2), 65-71. doi:10.1016/0037-0738(95)00080-

    Effects of Cu/Zn Superoxide Dismutase (sod1) Genotype and Genetic Background on Growth, Reproduction and Defense in Biomphalaria glabrata

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    Resistance of the snail Biomphalaria glabrata to the trematode Schistosoma mansoni is correlated with allelic variation at copper-zinc superoxide dismutase (sod1). We tested whether there is a fitness cost associated with carrying the most resistant allele in three outbred laboratory populations of snails. These three populations were derived from the same base population, but differed in average resistance. Under controlled laboratory conditions we found no cost of carrying the most resistant allele in terms of fecundity, and a possible advantage in terms of growth and mortality. These results suggest that it might be possible to drive resistant alleles of sod1 into natural populations of the snail vector for the purpose of controlling transmission of S. mansoni. However, we did observe a strong effect of genetic background on the association between sod1 genotype and resistance. sod1 genotype explained substantial variance in resistance among individuals in the most resistant genetic background, but had little effect in the least resistant genetic background. Thus, epistatic interactions with other loci may be as important a consideration as costs of resistance in the use of sod1 for vector manipulation

    Mosaic Convergence of Rodent Dentitions

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    BACKGROUND:Understanding mechanisms responsible for changes in tooth morphology in the course of evolution is an area of investigation common to both paleontology and developmental biology. Detailed analyses of molar tooth crown shape have shown frequent homoplasia in mammalian evolution, which requires accurate investigation of the evolutionary pathways provided by the fossil record. The necessity of preservation of an effective occlusion has been hypothesized to functionally constrain crown morphological changes and to also facilitate convergent evolution. The Muroidea superfamily constitutes a relevant model for the study of molar crown diversification because it encompasses one third of the extant mammalian biodiversity. METHODOLOGY/PRINCIPAL FINDINGS:Combined microwear and 3D-topographic analyses performed on fossil and extant muroid molars allow for a first quantification of the relationships between changes in crown morphology and functionality of occlusion. Based on an abundant fossil record and on a well resolved phylogeny, our results show that the most derived functional condition associates longitudinal chewing and non interlocking of cusps. This condition has been reached at least 7 times within muroids via two main types of evolutionary pathways each respecting functional continuity. In the first type, the flattening of tooth crown which induces the removal of cusp interlocking occurs before the rotation of the chewing movement. In the second type however, flattening is subsequent to rotation of the chewing movement which can be associated with certain changes in cusp morphology. CONCLUSION/SIGNIFICANCE:The reverse orders of the changes involved in these different pathways reveal a mosaic evolution of mammalian dentition in which direction of chewing and crown shape seem to be partly decoupled. Either can change in respect to strong functional constraints affecting occlusion which thereby limit the number of the possible pathways. Because convergent pathways imply distinct ontogenetic trajectories, new Evo/Devo comparative studies on cusp morphogenesis are necessary

    Collection of substantial amount of fine and ultrafine particles during the combustion of miscanthus and forest residues in small and medium scale boilers for morphological and chemical characterizations

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    Renewable energies are destined to play a very important role in the future world energy balance. Among these energies, biomass production and utilization is growing considerably since it offers the possibility to provide partial substitution of fossil fuels. If health impacts of fine particles (PM2.5) from diesel combustion are well documented (Gangwar et al., 2012), those from biomass combustion need substantial information and improvements. Size fractionations of PM2.5 have to be performed in order to both determine morphological and chemical characteristics, these properties being essential for biological effects. Particulate matter was sampled during combustion of miscanthus and forest residues in medium and small scale biomass boilers (400 kW from Köb Pyrot and 40 kW from REKA). Fly ashes from medium scale boiler were sampled with a cyclone device and their granulometry was studied with both optical microscope and Malvern laser granulometer. PM2.5 (sized in the range of 0.4 μm to 2.07 μm) from low scale boiler were sampled using a DEKATI DGI impactor modified for substantial PM collection. A quick overview of setup modifications for manual impactor will be developed. Particles were observed using fluorescence microscopy. A semi-quantitative method to compare fly ashes fluorescence was developped using ImageJ (Schneider et al., 2012). Speciation of organic compounds Polycyclic Aromatic Hydrocarbon (PAH) and Humic Like Substances (HULIS) was determined on PM2.5 and fly ashes. A correlation between observed fluorescence and concentration was attempted

    Evolution of the genus Eucricetodon (Rodentia, Mammalia) from the Valley of Lakes (Mongolia): a taxonomical description and update on the stratigraphical distribution

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    The Oligocene fossil deposits from Valley of Lakes in Central Mongolia have provided a wealth of rodent fossils. Among these, cricetids are a very important part. To date, only the Miocene genera have been described in detail. Here, we focus on the Oligocene genus Eucricetodon from this region. Eucricetodontinae are the most abundant fossils in the Oligocene Valley of Lakes faunas. The present study consists of the description of five species of cricetid rodents from 43 localities ranging in age from the early Oligocene to the early-late Oligocene. In addition to Eucricetodon asiaticus described in Mongolia in 1923, we have found Eucricetodon bagus and Eucricetodon jilantaiensis that were described from Nei Mongol and Eucricetodon occidentalis discovered in Kazakhstan. This taxonomical study provides new information regarding the evolution of the Cricetidae in Central and Eastern Asia during the Oligocene and, more particularly, regarding their phylogenetic relationships and the evolutionary trends

    In silico-designed lignin peroxidase from Phanerochaete chrysosporium shows enhanced acid stability for depolymerization of lignin

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    Background: The lignin peroxidase isozyme H8 from the white-rot fungus Phanerochaete chrysosporium (LiPH8) demonstrates a high redox potential and can efficiently catalyze the oxidation of veratryl alcohol, as well as the degradation of recalcitrant lignin. However, native LiPH8 is unstable under acidic pH conditions. This characteristic is a barrier to lignin depolymerization, as repolymerization of phenolic products occurs simultaneously at neutral pH. Because repolymerization of phenolics is repressed at acidic pH, a highly acid-stable LiPH8 could accelerate the selective depolymerization of recalcitrant lignin. Results: The engineered LiPH8 was in silico designed through the structural superimposition of surface-active site-harboring LiPH8 from Phanerochaete chrysosporium and acid-stable manganese peroxidase isozyme 6 (MnP6) from Ceriporiopsis subvermispora. Effective salt bridges were probed by molecular dynamics simulation and changes to Gibbs free energy following mutagenesis were predicted, suggesting promising variants with higher stability under extremely acidic conditions. The rationally designed variant, A55R/N156E-H239E, demonstrated a 12.5-fold increased half-life under extremely acidic conditions, 9.9-fold increased catalytic efficiency toward veratryl alcohol, and a 7.8-fold enhanced lignin model dimer conversion efficiency compared to those of native LiPH8. Furthermore, the two constructed salt bridges in the variant A55R/N156E-H239E were experimentally confirmed to be identical to the intentionally designed LiPH8 variant using X-ray crystallography (PDB ID: 6A6Q). Conclusion: Introduction of strong ionic salt bridges based on computational design resulted in a LiPH8 variant with markedly improved stability, as well as higher activity under acidic pH conditions. Thus, LiPH8, showing high acid stability, will be a crucial player in biomass valorization using selective depolymerization of lignin
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