97 research outputs found

    Nou gènere i nova nova espècie de cranc portunoid: Archaeoportunus isabenensis, de l’Eocè Inferior d’Osca (Aragó) i Lleida (Catalunya)

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    Crabs recovered from marly strata of the upper Roda Formation (Ypresian) at Isàvena (Huesca, Aragón), and the Ypresian of Lleida (Catalonia), exhibit a clear set of characteristics, mainly in chelipeds and dorsal carapace that favour assignment to the superfamily Portunoidea, and confirm a close relationship with the family Portunidae. However, the presence of important and easily distinguished features, such as the strongly marked dorsal ridges or notably narrow sternum, leads us to erect a new genus and species, Archeoportunus isabenensis gen. nov., sp. nov., and a new family, the Archaeoportunidae fam. nov. The ventral features of the new taxon, in particular the fairly narrow sternum which notably becomes even narrower posteriorly, the strongly downturned sternites 1-4, bearing strong swellings, and the general adaptation of sternum, pleon and pereiopods, substantiates the basal condition of the new taxon within the Portunoidea and also contributes to current knowledge of evolutionary issues within that group. This publication principally serves to validate the nomenclatural acts in Artal et al. (2013), in order to fulfil the requirements outlined in ICZN (2012).Els crancs recuperats en els estrats margosos de la formació Roda (Ipresià), a Isàvena (Osca, Aragó) així com a l’Ipresià de Lleida (Catalunya), presenten un conjunt de caràcters, principalment en els quelípedes i en la closca dorsal que permeten la seva assignació a la superfamília Portunoidea, al mateix temps que confirmen una relació propera amb la família Portunidae. Tanmateix, la presència d’estructures fàcilment distingibles com les carenes dorsals molt marcades o l’estèrnum estret, ens duu a erigir un nou gènere i espècie, Archaoportunus isabenensis, així com una nova família, Archaeoportunidae. Les estructures ventrals del nou tàxon, en particular l’estèrnum toràcic que s’estreteix posteriorment, les esternites toràciques 1-4 fortament arquejades i amb prominents inflors, i l’adaptació general de l’estèrnum, plèon i pereopodis, corrobora la condició basal del nou tàxon dins dels Portunoidea i a la vegada contribueix al coneixement de l’evolució d’aquest grup. La present publicació serveix per a validar els actes de nomenclatura establerts en Artal et al. (2013) per tal de complir els requisits descrits a ICZN (2012)

    Filling the early Eocene gap of paguroids (Decapoda, Anomura): a new highly diversified fauna from the Spanish Pyrenees (Serraduy Formation, Graus-Tremp Basin)

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    A highly diversified fauna of hermit crabs associated with reef environments from the Serraduy Formation (lower Eocene) in the southern Pyrenees (Huesca, Spain) is described. Other European Eocene outcrops have yielded paguroids associated with a single environment; however, the studied association represents one of the highest paguroid diversities in a single Eocene outcrop worldwide. The new material increases the diversity of known fossil paguroids, including eight species from which six are new: Clibanarius isabenaensis n. sp., Parapetrochirus serratus n. sp., Dardanus balaitus n. sp., ?Petrochirus sp., Eocalcinus veteris n. sp., ?Pagurus sp., Paguristes perlatus n. sp., and Anisopagurus primigenius n. sp. We erected a new combination for Paguristes sossanensis De Angeli and Caporiondo, 2009 and Paguristes cecconi De Angeli and Caporiondo, 2017 and transfer them to the genus Clibanarius. This association contains the oldest record of the genera Eocalcinus and Anisopagurus. Our data demonstrate that paguroids were diverse by the early Eocene in coral-reef environments and fill an important gap between the poorly known Paleocene assemblages and the more diverse mid- to late Eocene ones

    A highly diverse dromioid crab assemblage (Decapoda, Brachyura) associated with pinnacle reefs in the lower Eocene of Spain

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    A highly diverse fauna of dromioid brachyurans from the Serraduy Formation (lower Eocene) in the western Pyrenees (Huesca, Spain) is described and illustrated. Recorded taxa are Mclaynotopus longispinosus new genus new species, Torodromia elongata n. gen. n. sp., Basidromilites glaessneri n. gen. n. sp., ?Basidromilites sp., Sierradromia gladiator n. gen. n. sp., Kromtitis isabenensis n. sp., and ?Basinotopus sp. Other European outcrops have yielded dromioids in association with specific environments, likely coral and sponge reef and siliciclastic soft bottoms; but the present material constitutes the most diverse dromioid assemblage from the lower Eocene worldwide. These dromioids co-occurred with a rich invertebrate fauna and lived near coral–algal reef mounds. Sedimentological data suggest that most of the fauna accumulated in fore reef settings as a result of storm activity. The present material greatly increases the diversity of known dromioid crabs associated with Eocene reef environments.UUID: http://zoobank.org/aed8cafa-7c64-4e70-bd45-9f357fc37a2

    Geometric motivic Poincar\'e series of quasi-ordinary singularities

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    The geometric motivic Poincar\'e series of a germ (S,0)(S,0) of complex algebraic variety takes into account the classes in the Grothendieck ring of the jets of arcs through (S,0)(S,0). Denef and Loeser proved that this series has a rational form. We give an explicit description of this invariant when (S,0)(S,0) is an irreducible germ of quasi-ordinary hypersurface singularity in terms of the Newton polyhedra of the logarithmic jacobian ideals. These ideals are determined by the characteristic monomials of a quasi-ordinary branch parametrizing (S,0)(S,0)

    Planck-LFI 44-GHz back end module

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    This work describes the principle of operation, assembly and performance of one branch of the 44 GHz back end module (BEM) for the Planck low frequency instrument (LFI). This subsystem constitutes a fully representative branch of the qualification-model version (QM). It includes waveguide to microstrip transition, GaAs pseudomorphic high electron mobility transistor (PHEMT) low noise amplifiers (LNA), bandpass filter, square-law detector and dc amplifier. The fundamentals of the design of the RF part are described and all of the components have been tested individually before integration. Using single tone and wideband noise stimuli, the output voltage has been measured for several input powers, in order to obtain the sensitivity factor of the complete BEM. The effective bandwidth and the equivalent noise temperature have been calculated from the measurements, taking into account the frequency dependence on the noise source and the BEM. Finally, the low frequency output power spectrum has been obtained and a maximum 1/f knee frequency around 200 Hz has been measured with a 3 dB output signal video bandwidth above 50 KHz.Peer Reviewe

    Very Low-Noise Differential Radiometer at 30 GHz for the PLANCK LFI

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    The PLANCK mission of the European Space Agency is devoted to produce sky maps of the cosmic microwave background radiation. The low-frequency instrument is a wide-band cryogenic microwave radiometer array operating at 30, 44, and 70 GHz. The design, test techniques, and performance of the complete differential radiometer at 30 GHz are presented. This elegant breadboard 30-GHz radiometer is composed of a front-end module (FEM) assembled at the Jodrell Bank Observatory, Cheshire, U.K., and a back-end module assembled at the Universidad de Cantabria, Cantabria, Spain, and Telecomunicacio/spl acute/, Universitat Polite/spl acute/cnica de Catalunya, Barcelona, Spain. The system noise temperature was excellent, mainly due to the very low noise performance of the FEM amplifiers, which achieved an average noise temperature of 9.4 K.Peer Reviewe

    An Aptian sponge-associated decapod crustacean assemblage from Cal Cassanyes (Catalonia, north-east Iberian Peninsula): Taxonomy and palaeoecological implications

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    A highly diverse decapod crustacean fauna is described from the classic Aptian outcrop of Cal Cassanyes (Castellet i la Gornal) in Catalonia. Although decapod crustaceans are a minor component of the rich invertebrate assemblages at that locality, the just over fifty specimens collected comprise sixteen taxa assignable to the Macrura, Anomura and Brachyura. Of these, the last-named are the most prominent group, comprising eleven species, representing seven families, inclusive of one representative of the Eubrachyura. On the basis of this material, two new genera and five new species are erected, namely Pagurus? garrafensis sp. nov., Garrafosopon gen. nov. angustus (Wright and Collins, 1972) comb. nov., Vectis blesai sp. nov., Mesodromilites prietoi sp. nov., Necrocarcinus mariae sp. nov. and Iberodorippe vinea gen. nov., sp. nov. In addition, Hoploparia sp., an indeterminate axiid and one paguroid, as well as one indeterminate galatheoid are recorded here. Material of Distefania incerta (Bell, 1863), the commonest species at the study site by far, of Goniodromites laevis (Van Straelen, 1940) and of Etyxanthosia fossa (Wright and Collins, 1972) represents the first Aptian and stratigraphically oldest records for these taxa. Added to this list are also Eodromites sp., Paranecrocarcinus? sp. and Pseudonecrocarcinus? sp. The high decapod crustacean diversity at Cal Cassanyes establishes this locality as the richest Aptian assemblage from the Iberian Peninsula, but also one of the richest in the world. The faunal assemblages here are dominated by sponges, and the varied composition of the decapod crustacean faunas can be linked to upwelling currents which provided abundant nutrients. In fact, the establishment of sponge communities played a crucial role in activating the food chain and functioned similarly to a patch reef, creating a relatively sheltered environment that facilitated the colonisation of other invertebrate communities, including decapod crustaceans. The latter occupied various trophic levels as both primary and secondary consumers. Current knowledge of Early Cretaceous decapod crustaceans is scant and hinders a thorough palaeobiogeographical analysis. The present study emphasises the challenges surrounding the identification of endemic taxa, thus impacting our understanding of decapod crustacean palaeobiogeography of the late Early Cretaceous

    Módulo posterior del radiómetro Planck a 30 GHz: modelo de calificación

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    The Back End Module at 30 GHz for the Planck mission has been manufactured in its Qualification Model version. Design, integration and main performances are described. Electrical, thermal and vibration tests, already done for space qualification, are summarised. This module consists basically in four identical branches based on broadband low noise amplification, direct detection and video amplification

    Stroke prevalence among the Spanish elderly: an analysis based on screening surveys

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    BACKGROUND: This study sought to describe stroke prevalence in Spanish elderly populations and compare it against that of other European countries. METHODS: We identified screening surveys -both published and unpublished- in Spanish populations, which fulfilled specific quality requirements and targeted prevalence of stroke in populations aged 70 years and over. Surveys covering seven geographically different populations with prevalence years in the period 1991–2002 were selected, and the respective authors were then asked to provide descriptions of the methodology and raw age-specific data by completing a questionnaire. In addition, five reported screening surveys in European populations furnished useful data for comparison purposes. Prevalence data were combined, using direct adjustment and logistic regression. RESULTS: The overall study population, resident in central and north-eastern Spain, totalled 10,647 persons and yielded 715 cases. Age-adjusted prevalences, using the European standard population, were 7.3% for men, 5.6% for women, and 6.4% for both sexes. Prevalence was significantly lower in women, OR 0.79 95% CI 0.68–0.93, increased with age, particularly among women, and displayed a threefold spatial variation with statistically significant differences. Prevalences were highest, 8.7%, in suburban, and lowest, 3.8%, in rural populations. Compared to pooled Spanish populations, statistically significant differences were seen in eight Italian populations, OR 1.39 95%CI (1.18–1.64), and in Kungsholmen, Sweden, OR 0.40 95%CI (0.27–0.58). CONCLUSION: Prevalence in central and north-eastern Spain is higher in males and in suburban areas, and displays a threefold geographic variation, with women constituting the majority of elderly stroke sufferers. Compared to reported European data, stroke prevalence in Spain can be said to be medium and presents similar age- and sex-specific traits
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