364 research outputs found

    Environmental control of conodont distribution in the Shawnee Group (Upper Pennsylvanian) of eastern Kansas

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    124 p., 16 pl., 18 fig.http://paleo.ku.edu/contributions.htm

    The La Coulée Formation, a new post-Acadian continental clastic unit bearing groundwater calcretes, Gaspé Peninsula, Quebec

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    A 1 km2 erosional remnant of the La Coulée Formation, a previously unrecognized stratigraphic unit, has been studied in the Percé area of the Gaspé Peninsula. It unconformably overlies folded Cambrian to Devonian rocks and is unconformably overlain by the mid-Carboniferous Bonaventure Formation. The erosional remnant includes the lowest 60 m of this newly identified formation of unknown thickness. Original sedimentary fades are limited to 50 m of breccia debris flows passing stratigraphically upward into 10m of conglomeratic debris flows. Groundwater calcrete formation has partially or completely transformed the lowest 30 m of the sequence. The depositional environment is interpreted as being related to a proximal continental alluvial fan. The nearby presence of a saline body of water is inferred to account for thick and massive groundwater calcrete formation and water-saturated debris flows in a relatively arid climatic context Most of the formation was eroded prior to deposition of the Bonaventure Formation. However, the basal groundwater calcretes were more widely preserved. They underlie the Bonaventure Formation in most of the Percé area and in the Saint-Elzéar area, close to a hundred kilometres to the southwest. Post-sedimentary faulting has affected both the La Coulée and Bonaventure formations. RÉSUMÉ La Formation de La Coulée, une unite stratigraphique nouvellement répertoriée, a été éudiée a I'intérieur d'une masse résiduelle de 1 km2 dans la région de Percé en Gaspésie. La séquence recouvre en discordance des roches plissees du Dévonien Inférieur et elle est recouverte en discordance par la Formation de Bonaventure qui est attribuée au Carbonifere moyen. La masse résiduelle inclue les 60 premiers mètres de cette formation nouvellement identifiée et d'une épaisseur inconnue. Les fades sédimentaires originels sont limités à cinquante mètres de coulees de débris bréchiques, passant à une dizaine de mètres de coulées de débris conglomératiques. La formation d'une calcrete phréatique affecte les premiers 30 mètres de la séquence, lesquels sont en partie ou complètement transformés. L'environnement sédimentaire est interprété comme étant lié à un còne de déjection continental dans sa partie proximale, mais la présence non-lointaine d'un plan d'eau salde est suggerée pour expliquer la formation de calcretes phréatiques épaisses et massives, ainsi que la saturation en eau des coulées de débris dans un contexte climatique relativement aride. La formation a presqu'entierement été érodée avant que ne survienne la sédimentation de la Formation de Bonaventure. Toutefois, la base de calcrete a été plus largement préservée, ce qui fait qu'on la retrouve sous la Formation de Bonaventure preque partout dans la region de Percé ainsi que dans la région de Saint-Elzéar, a presqu'une centaine de kilomètres au sud-ouest. Des failles post-sédimentaires ont affecté à la fois la Formation de La Coulée et la Formation de Bonaventure

    Pseudomonas aeruginosa pilin activates the inflammasome

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    IL-1 beta is produced from inactive pro-IL-1 beta by activation of caspase-1 brought about by a multi-subunit protein platform called the inflammasome. Many bacteria can trigger inflammasome activity through flagellin activation of the host protein NLRC4. However, strains of the common human pathogen Pseudomonas aeruginosa lacking flagellin can still activate the inflammasome. We set out to identify what non-flagellin components could produce this activation. Using mass spectroscopy, we identified an inflammasome-activating factor from P. aeruginosa as pilin, the major component of the type IV bacterial pilus. Purified pilin introduced into mouse macrophages by liposomal delivery activated caspase-1 and led to secretion of mature IL-1 beta, as did recombinant pilin purified from Escherichia coli. This was dependent on caspase-1 but not on the host inflammasome proteins NLRC4, NLRP3 or ASC. Mutants of P. aeruginosa strain PA103 lacking pilin did not activate the inflammasome following infection of macrophages with live bacteria. Type III secretion remained intact in the absence of pili, showing this was not due to a lack of effector delivery. Our observations show pilin is a novel activator of the inflammasome in addition to flagellin and the recently described PrgJ protein family, the basal body rod component of the type III apparatu

    A new fireworm (Amphinomidae) from the Cretaceous of Lebanon identified from three-dimensionally preserved myoanatomy

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    © 2015 Parry et al. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. The attached file is the published version of the article

    A study of the breakdown of the quasi-static approximation at high densities and its effect on the helium-like K ALPHA complex of nickel, iron, and calcium

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    The General Spectral Modeling (GSM) code employs the quasi-static approximation, a standard, low-density methodology that assumes the ionization balance is separable from a determination of the excited-state populations that give rise to the spectra. GSM also allows for some states to be treated only as contributions to effective rates. While these two approximations are known to be valid at low densities, this work investigates using such methods to model high-density, non-LTE emission spectra and determines at what point the approximations break down by comparing to spectra produced by the LANL code ATOMIC which makes no such approximations. As both approximations are used by other astrophysical and low-density modeling codes, the results should be of broad interest. He-like Kα\alpha emission spectra are presented for Ni, Fe, and Ca, in order to gauge the effect of both approximations employed in GSM. This work confirms that at and above the temperature of maximum abundance of the He-like ionization stage, the range of validity for both approximations is sufficient for modeling the low- and moderate-density regimes one typically finds in astrophysical and magnetically confined fusion plasmas. However, a breakdown does occur for high densities; we obtain quantitative limits that are significantly higher than previous works. This work demonstrates that, while the range of validity for both approximations is sufficient to predict the density-dependent quenching of the z line, the approximations break down at higher densities. Thus these approximations should be used with greater care when modeling high-density plasmas such as those found in inertial confinement fusion and electromagnetic pinch devices.Comment: Accepted by Physical Review A (http://pra.aps.org/). 11 pages + LANL cover, 5 figures. Will update citation information as it becomes available. Abbreviated abstract is listed her
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