199 research outputs found

    Comment on Reply to Comment of Finger et al. (2013) on: 'Evidence for an Early-Middle Miocene age of the Navidad Formation (central Chile): Paleontological, paleoclimatic and tectonic implications' of Gutiérrez et al. (2013, Andean Geology 40 (1): 66-78)

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    Indexación: Web of Science; ScieloIn their answer to our Comment (Finger et al., 2013), Le Roux et al. (2013) misunderstand several of our remarks and present what we view as f lawed arguments, principally their case for a shallow-marine environment for part of the Navidad Formation. We do not wish to see this exchange evolve into an endless discussion, but we feel obligated to clarify some points. We think this is necessary because of history and importance of the Navidad Formation as the reference for the marine Miocene of Chile. Here we also expound upon some concepts relevant to the distinction between shallow-and deep-marine environments

    A revision of the type specimens of Tertiary molluscs from Chile and Argentina described by d`Orbigny (1842), Sowerby (1846), and Hupé (1854)

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    Fil: Griffin, Miguel. Facultad de Ciencias Exactas y Naturales; Universidad Nacional de La PampaFil: Nielsen, Sven N.. GeoForschungsZentrum Potsdam; Potsdam; German

    The Australasian muricid gastropod Lepsiella as Pleistocene visitor to southernmost South America

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    Six shells belonging to a muricid gastropod species were recovered from a Pleistocene marine raised beach located on Navarino Island, in southern South America. None of the living species in the Beagle Channel or in the area is close, and none of the fossil species in the vicinity regions shows the diagnostic characters of the Navarino Pleistocene fossils. Our material resembles Lepsiella baileyana from southern Australia, although some differences in the suture and in the spire outline are recognized. Haustrinae was previously confined geographically to New Zealand and to the temperate coast of Australia, now extending its range of distribution to southern South America. This finding of Lepsiella ukika sp. nov. is best explained on the basis of transoceanic migration from Australasia by means of the Antarctic Circumpolar Current perhaps during a Quaternary glacial period. The presence of this Pleistocene visitor in southern South America is important because it clearly demonstrates that transcontinental traverse of taxa with direct (non-planktonic) development might have happened by rafting on kelp that served as transport platforms.Fil: Gordillo, Sandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Ciencias de la Tierra; Argentina. Universidad Nacional de Cordoba. Facultad de Ciencias Exactas Fisicas y Naturales. Centro de Investigaciones Paleobiologicas; ArgentinaFil: Nielsen, Sven N.. Universität Zu Kiel; Alemania. Universidad Austral de Chile; Chil

    Survival Probability of a Doorway State in regular and chaotic environments

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    We calculate survival probability of a special state which couples randomly to a regular or chaotic environment. The environment is modelled by a suitably chosen random matrix ensemble. The exact results exhibit non--perturbative features as revival of probability and non--ergodicity. The role of background complexity and of coupling complexity is discussed as well.Comment: 19 pages 5 Figure

    Neogene Bony Fishes from the Bahía Inglesa Formation, Northern Chile

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    Despite being one of the richest Neogene deposits of marine fossil vertebrates along the Pacific coast of South America, no detailed study of bony fishes from the Bahía Inglesa Formation has been carried out. Through the revision of historical collections of the Caldera Paleontological Museum, we describe 27 fossil remains of bony fishes. Fossils described here are distributed in 13 taxa. Among these, Sardinops sp. cf. S. sagax (Clupeidae) represents the first fossil record of the genus for Chile, Labrodon sp. (Labridae) and Stelliferinae (Sciaenidae) are the first respective records for the southeast Pacific Ocean, Sarda sp. (Scombridae) represents the first fossil record for South America, Semicossyphus sp. (Labridae) and Anisotremus sp. (Haemulidae) are the first respective records for the Southern Hemisphere. Gymnosarda sp. (Scombridae) is described for the first time for the Neogene. We performed a paleobathymetric analysis of fossil fishes, including elasmobranchs, to understand the paleoenvironment followed by a similarity analysis that compares the faunal composition of the Bahía Inglesa Fm. with other fossil assemblages for the Pacific of South America. Our results show that the fish fauna from the Bahía Inglesa Fm. likely represents a depth range of 98 to 382 m with a mean depth range of 252 m in an uppermost bathyal environment. The assemblage from the Bahía Inglesa Fm. shows low taxonomic similarity levels with other Neogene geological units from the southeast Pacific Ocean. The study represents the first paleoecological and paleobiogeographic analysis of the fossil fish fauna from the Southeast Pacific. Key words. Atacama region. Clupeiformes. Eastern Pacific. Paleoenviroments. Perciformes. Ophidiiformes

    The PTPN22 C1858T gene variant is associated with proinsulin in new-onset type 1 diabetes

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    <p>Abstract</p> <p>Background</p> <p>The protein tyrosine phosphatase nonreceptor type 2 (<it>PTPN22</it>) has been established as a type 1 diabetes susceptibility gene. A recent study found the C1858T variant of this gene to be associated with lower residual fasting C-peptide levels and poorer glycemic control in patients with type 1 diabetes. We investigated the association of the C1858T variant with residual beta-cell function (as assessed by stimulated C-peptide, proinsulin and insulin dose-adjusted HbA<sub>1c</sub>), glycemic control, daily insulin requirements, diabetic ketoacidosis (DKA) and diabetes-related autoantibodies (IA-2A, GADA, ICA, ZnT8Ab) in children during the first year after diagnosis of type 1 diabetes.</p> <p>Methods</p> <p>The C1858T variant was genotyped in an international cohort of children (n = 257 patients) with newly diagnosed type 1 diabetes during 12 months after onset. We investigated the association of this variant with liquid-meal stimulated beta-cell function (proinsulin and C-peptide) and antibody status 1, 6 and 12 months after onset. In addition HbA<sub>1c </sub>and daily insulin requirements were determined 1, 3, 6, 9 and 12 months after diagnosis. DKA was defined at disease onset.</p> <p>Results</p> <p>A repeated measurement model of all time points showed the stimulated proinsulin level is significantly higher (22%, p = 0.03) for the T allele carriers the first year after onset. We also found a significant positive association between proinsulin and IA levels (est.: 1.12, p = 0.002), which did not influence the association between <it>PTPN22 </it>and proinsulin (est.: 1.28, p = 0.03).</p> <p>Conclusions</p> <p>The T allele of the C1858T variant is positively associated with proinsulin levels during the first 12 months in newly diagnosed type 1 diabetes children.</p

    Nyt projekt om stribedyrkning og biodiversitet (StripCrop)

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    Indenfor de seneste årtier har der været en stigende interesse for samtidig dyrkning af flere afgrøder stribevis i en mark (stribedyrkning). StripCrop er et nyt dansk projekt, som beskæftiger sig med emnet. I artiklen introduceres projektet
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