31 research outputs found

    Nouvel Oriocrassatellinae du Pennsylvanien du Brésil et distribution spatio-temporelle d’Oriocrassatella

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    Oriocrassatella Etheridge Jr., 1907 is a long range crassatellid bivalve genus well recognized in shallow waters of epeiric seas throughout the upper part of Paleozoic. The first occurrences of this genus are recorded in the sedimentary successions of the Gondwana, both in Australia and South America. However, the geographic and age distribution of Oriocrassatella in Late Mississippian deposits of Australia and Argentina may indicate an earliest Visean or even a pre-Visean origin for the genus. Following its origin in Early Carboniferous a complex paleobiogeographic history from Southern to Northern Hemisphere took place in the Permian. During its initial dispersal phase from Late Carboniferous to the Early Permian the genus thrived in cold water environments associated to the Late Paleozoic Gondwana glaciation. Shallow-water bottoms of the warm waters of the central Gondwana fringe and Laurussia were colonized by Oriocrassatella only during Early Permian times when the genus became cosmopolitan. A new species of this genus is described herein, Oriocrassatella piauiensis n.   sp., recorded from the Piauí Formation, Pennsylvanian of the Parnaíba Basin. This new species may represent an early adaptation to warm waters. However, based on available data, species of this genus seem to have adapted definitely to warm water environments probably related the Late Pennsylvanian interglacial phases. In these phases, climatic barrier were interrupted allowing the faunal interchange and larval dispersion following a South to North migration route through the eastern margins of Gondwana and the eastern Paleotethys.Oriocrassatella Etheridge Jr., 1907 est un crassatellidé à large distribution stratigraphique, bien connu dans les mers épicontinentales en eaux peu profondes, caractéristique du Paléozoïque supérieur. Ce genre apparaît pour la première fois dans des dépôts sédimentaires du Gondwana, en Australie et en Amérique du Sud. D’après sa distribution spatio-temporelle dans des dépôts du Mississippien supérieur, Oriocrassatella serait originaire du début du Viséen, ou même pré-viséenne. Par la suite, depuis le Carbonifère inférieur jusqu’au Permien, ce genre a eu une histoire paléobiogéographique complexe allant de l’hémisphère Sud vers l’hémisphère Nord. Pendant la phase initiale de dispersion à partir du Carbonifère supérieur jusqu’au Permien inférieur, ce genre a prospéré dans un milieu dominé par des eaux froides du Gondwana, suite à la glaciation du Paléozoïque supérieur. Les eaux littorales chaudes du Gondwana central et de Laurussia ont été colonisées par Oriocrassatella uniquement durant le Permien inférieur, parce que ce genre est devenu cosmopolite. Une espèce nouvelle, O. piauiensis n. sp., est décrite de la Formation Piauí du Pennsylvanien du bassin du Parnaíba ; elle pourrait représenter une première adaptation aux eaux chaudes. En outre, et en s’appuyant sur les données disponibles, d’autres espèces d’Oriocrassatella se seraient aussi définitivement adaptées à des milieux en eaux chaudes au cours des périodes interglaciaires du Pennsylvanien tardif, car des barrières climatiques ont disparu, favorisant des échanges de faune avec dispersion des larves, et migration du sud vers le nord le long des bordures est du Gondwana et de la Paléotéthys.Fil: Anelli, Luiz E.. Universidade de Sao Paulo; BrasilFil: Simões, Marcello G.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Gonzalez, Carlos Roberto. Fundación Miguel Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Souza, Paulo A.. Universidade Federal do Rio Grande do Sul; Brasi

    Microbially induced pseudotraces from a Pantanal soda lake, Brazil : Alternative interpretations for Ediacaran simple trails and their limits

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    Despite the absence of metazoans, structures resembling animal traces are common in a soda lake from the western Brazil Pantanal wetland. Pantanal soda lakes are ecologically extreme environments that preclude complex life, allowing extremophiles to flourish. Direct observation indicates that these structures are pseudotraces, representing groove marks that result from the interaction of wave-transported floating rafts of epibenthic microbial mat fragments with the substrate. Variations in wind/wave direction and intensity result in marks of different size and morphology. The most common pseudotraces are simple and slightly curved, narrow grooves (type 1), whereas others are straight and present raised lateral ridges (type 2). Both are V-shaped in cross section. Type 3 comprises long, sinuous, shallow grooves, displaying internal crescentic laminated infill and U-shaped cross section. The similarity of these pseudotraces to Ediacaran structures usually interpreted as animal trace fossils suggests that care should be exercised in their analysis. A set of criteria is proposed to differentiate microbially induced pseudotraces from trace fossils. Analysis of Ediacaran structures needs to be performed on a case-by-case basis, taking into account morphology, orientation, and preservation style of the structure, sedimentary environment, and presence or absence of microbial mats.Centro de Investigaciones Geológica

    Detection of ice core particles via deep neural networks

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    Insoluble particles in ice cores record signatures of past climate parameters like vegetation dynamics, volcanic activity, and aridity. For some of them, the analytical detection relies on intensive bench microscopy investigation and requires dedicated sample preparation steps. Both are laborious, require in-depth knowledge, and often restrict sampling strategies. To help overcome these limitations, we present a framework based on flow imaging microscopy coupled to a deep neural network for autonomous image classification of ice core particles. We train the network to classify seven commonly found classes, namely mineral dust, felsic and mafic (basaltic) volcanic ash grains (tephra), three species of pollen (Corylus avellana, Quercus robur, Quercus suber), and contamination particles that may be introduced onto the ice core surface during core handling operations. The trained network achieves 96.8 % classification accuracy at test time. We present the system's potential and its limitations with respect to the detection of mineral dust, pollen grains, and tephra shards, using both controlled materials and real ice core samples. The methodology requires little sample material, is non-destructive, fully reproducible, and does not require any sample preparation procedures. The presented framework can bolster research in the field by cutting down processing time, supporting human-operated microscopy, and further unlocking the paleoclimate potential of ice core records by providing the opportunity to identify an array of ice core particles. Suggestions for an improved system to be deployed within a continuous flow analysis workflow are also presented

    Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

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    The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

    Familial hypercholesterolaemia in children and adolescents from 48 countries: a cross-sectional study

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    Background: Approximately 450 000 children are born with familial hypercholesterolaemia worldwide every year, yet only 2·1% of adults with familial hypercholesterolaemia were diagnosed before age 18 years via current diagnostic approaches, which are derived from observations in adults. We aimed to characterise children and adolescents with heterozygous familial hypercholesterolaemia (HeFH) and understand current approaches to the identification and management of familial hypercholesterolaemia to inform future public health strategies. Methods: For this cross-sectional study, we assessed children and adolescents younger than 18 years with a clinical or genetic diagnosis of HeFH at the time of entry into the Familial Hypercholesterolaemia Studies Collaboration (FHSC) registry between Oct 1, 2015, and Jan 31, 2021. Data in the registry were collected from 55 regional or national registries in 48 countries. Diagnoses relying on self-reported history of familial hypercholesterolaemia and suspected secondary hypercholesterolaemia were excluded from the registry; people with untreated LDL cholesterol (LDL-C) of at least 13·0 mmol/L were excluded from this study. Data were assessed overall and by WHO region, World Bank country income status, age, diagnostic criteria, and index-case status. The main outcome of this study was to assess current identification and management of children and adolescents with familial hypercholesterolaemia. Findings: Of 63 093 individuals in the FHSC registry, 11 848 (18·8%) were children or adolescents younger than 18 years with HeFH and were included in this study; 5756 (50·2%) of 11 476 included individuals were female and 5720 (49·8%) were male. Sex data were missing for 372 (3·1%) of 11 848 individuals. Median age at registry entry was 9·6 years (IQR 5·8-13·2). 10 099 (89·9%) of 11 235 included individuals had a final genetically confirmed diagnosis of familial hypercholesterolaemia and 1136 (10·1%) had a clinical diagnosis. Genetically confirmed diagnosis data or clinical diagnosis data were missing for 613 (5·2%) of 11 848 individuals. Genetic diagnosis was more common in children and adolescents from high-income countries (9427 [92·4%] of 10 202) than in children and adolescents from non-high-income countries (199 [48·0%] of 415). 3414 (31·6%) of 10 804 children or adolescents were index cases. Familial-hypercholesterolaemia-related physical signs, cardiovascular risk factors, and cardiovascular disease were uncommon, but were more common in non-high-income countries. 7557 (72·4%) of 10 428 included children or adolescents were not taking lipid-lowering medication (LLM) and had a median LDL-C of 5·00 mmol/L (IQR 4·05-6·08). Compared with genetic diagnosis, the use of unadapted clinical criteria intended for use in adults and reliant on more extreme phenotypes could result in 50-75% of children and adolescents with familial hypercholesterolaemia not being identified. Interpretation: Clinical characteristics observed in adults with familial hypercholesterolaemia are uncommon in children and adolescents with familial hypercholesterolaemia, hence detection in this age group relies on measurement of LDL-C and genetic confirmation. Where genetic testing is unavailable, increased availability and use of LDL-C measurements in the first few years of life could help reduce the current gap between prevalence and detection, enabling increased use of combination LLM to reach recommended LDL-C targets early in life

    Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

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    Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

    Significado paleobiológico de agrupamentos (coloniais/ gregários) de Conularia quichua Ulrich, 1890 (Cnidaria), Formação Ponta Grossa, Devoniano (Pragiano-Emsiano), Bacia do Paraná, Brasil

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    The Conularia beds of the Ponta Grossa Formation (Devonian) of the Paraná Basin, southern Brazil, yield well-preserved specimens of Conularia quichua Ulrich and Paraconularia africana Sharpe. Many of these are preserved in life orientation. Also, one of the C. quichua specimens has five faces instead of four, providing additional evidence of a cnidarian affinity for conulariids. Conulariids occur in the Jaguariaíva Member (or Sequence B, transgressive system tract) containing several obrution deposits beneath marine flooding surfaces. Taphonomic data obtained from these beds show conclusively that both C. quichua and P. africana were epibenthic, sessile invertebrates originally oriented with their long axis perpendicular to the bottom and with their aperture opening upward. Of the 136 C. quichua specimens examined here, 125 occur isolated. Eleven of the C. quichua specimens collectively occur in five discrete clusters consisting of two or three specimens. All of the clustered specimens are fully inflated (exhibiting a rectangular transverse cross section) or slightly compressed longitudinally. In all of these specimens the apex is missing, and thus the problem of whether the clusters were clonal colonies or formed through preferential larval settlement cannot be resolved conclusively. However, in the single cluster consisting of three specimens, the specimens are oriented perpendicular to bedding, and thus they do not converge adapically. The three specimens are in contact with each other along the upper portion of their median region. These and the lack of any evidence of a sheet of budding stolons, suggest that this cluster was formed by preferential larval settlement. © Asociación Paleontológica Argentina

    The temporal resolution of epibiont assemblages: Are they ecological snapshots or overexposures?

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    The effects of time averaging on the fossil record of soft-substrate marine faunas have been investigated in great detail, but the temporal resolution of epibiont assemblages has been inferred only from limited-duration deployment experiments. Individually dated shells provide insight into the temporal resolution of epibiont assemblages and the taphonomic history of their hosts over decades to centuries. Epibiont abundance and richness were evaluated for 86 dated valves of the rhynchonelliform brachiopod Bouchardia rosea collected from the inner shelf. Maximum abundance occurred on shells less than 400 yr old, and maximum diversity was attained within a century. Taphonomic evidence does not support models of live-host colonization, net accumulation, or erasure of epibionts over time. Encrustation appears to have occurred during a brief interval between host death and burial, with no evidence of significant recolonization of exhumed shells. Epibiont assemblages of individually dated shells preserve ecological snapshots, despite host-shell time averaging, and may record long-term ecological changes or anthropogenic environmental changes. Unless the ages of individual shells are directly estimated, however, pooling shells of different ages artificially reduces the temporal resolution of their encrusting assemblages to that of their hosts, an artifact of analytical time averaging. © 2006 by The University of Chicago. All rights reserved
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