76 research outputs found

    Un itinerario paleoicnológico por el Prepirineo y Valle del Ebro de Aragón

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    Se pretende poner en valor la gran riqueza de yacimientos de icnitas de mamíferos y aves del Cenozoico del Prepirineo y del Valle del Ebro de Aragón diseñando un itinerario paleoicnológico que incluya los principales yacimientos. Además de la importancia científica, se quiere destacar el valor de este patrimonio paleontológico como recurso turístico y didáctico. En algunos de estos yacimientos se han llevado a cabo a lo largo de las últimas décadas diversas acciones de conservación y adecuación que permiten el acceso y la visita a los mismos, lo que posibilita su potenciación como recurso socio-económico del territorio. This work aims to put in value the great wealth of mammal and avian tracksites of the Cenozoic from the Pre- pyrenees and the Ebro Valley, by designing a paleoichnological itinerary which includes the main sites. In addition to the scientific importance, we want to emphasize the value of this paleontological heritage as a tourist and educational resource. In some of these sites, conservation and adaptation actions have been carried out over the last decades. That allows accessing and visiting these sites, and thus, strengthening them as socio-economic resource of the region

    Age-Related Differences in Susceptibility to Carcinogenesis: A Quantitative Analysis of Empirical Animal Bioassay Data

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    In revising cancer risk assessment guidelines, the U.S. Environmental Protection Agency (EPA) analyzed animal cancer bioassay data over different periods of life. In this article, we report an improved analysis of these data (supplemented with some chemical carcinogenesis observations not included in the U.S. EPA’s original analysis) and animal bioassay studies of ionizing radiation. We use likelihood methods to avoid excluding cases where no tumors were observed in specific groups. We express dosage for animals of different weights on a metabolically consistent basis (concentration in air or food, or per unit body weight to the three-quarters power). Finally, we use a system of dummy variables to represent exposures during fetal, preweaning, and weaning–60-day postnatal periods, yielding separate estimates of relative sensitivity per day of dosing in these intervals. Central estimate results indicate a 5- to 60-fold increased carcinogenic sensitivity in the birth–weaning period per dose ÷ (body weight(0.75)-day) for mutagenic carcinogens and a somewhat smaller increase—centered about 5-fold—for radiation carcinogenesis per gray. Effects were greater in males than in females. We found a similar increased sensitivity in the fetal period for direct-acting nitrosoureas, but no such increased fetal sensitivity was detected for carcinogens requiring metabolic activation. For the birth–weaning period, we found an increased sensitivity for direct administration to the pups similar to that found for indirect exposure via lactation. Radiation experiments indicated that carcinogenic sensitivity is not constant through the “adult” period, but the dosage delivered in 12- to 21-month-old animals appears a few-fold less effective than the comparable dosage delivered in young adults (90–105 days of age)

    101 Dothideomycetes genomes: A test case for predicting lifestyles and emergence of pathogens.

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    Dothideomycetes is the largest class of kingdom Fungi and comprises an incredible diversity of lifestyles, many of which have evolved multiple times. Plant pathogens represent a major ecological niche of the class Dothideomycetes and they are known to infect most major food crops and feedstocks for biomass and biofuel production. Studying the ecology and evolution of Dothideomycetes has significant implications for our fundamental understanding of fungal evolution, their adaptation to stress and host specificity, and practical implications with regard to the effects of climate change and on the food, feed, and livestock elements of the agro-economy. In this study, we present the first large-scale, whole-genome comparison of 101 Dothideomycetes introducing 55 newly sequenced species. The availability of whole-genome data produced a high-confidence phylogeny leading to reclassification of 25 organisms, provided a clearer picture of the relationships among the various families, and indicated that pathogenicity evolved multiple times within this class. We also identified gene family expansions and contractions across the Dothideomycetes phylogeny linked to ecological niches providing insights into genome evolution and adaptation across this group. Using machine-learning methods we classified fungi into lifestyle classes with >95 % accuracy and identified a small number of gene families that positively correlated with these distinctions. This can become a valuable tool for genome-based prediction of species lifestyle, especially for rarely seen and poorly studied species

    Manus track preservation bias as a key factor for assessing trackmaker identity and quadrupedalism in basal ornithopods.

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    BACKGROUND: The Las Cerradicas site (Tithonian-Berriasian), Teruel, Spain, preserves at least seventeen dinosaur trackways, some of them formerly attributed to quadrupedal ornithopods, sauropods and theropods. The exposure of new track evidence allows a more detailed interpretation of the controversial tridactyl trackways as well as the modes of locomotion and taxonomic affinities of the trackmakers. METHODOLOGY/PRINCIPAL FINDINGS: Detailed stratigraphic analysis reveals four different levels where footprints have been preserved in different modes. Within the tridactyl trackways, manus tracks are mainly present in a specific horizon relative to surface tracks. The presence of manus tracks is interpreted as evidence of an ornithopod trackmaker. Cross-sections produced from photogrammetric digital models show different depths of the pes and manus, suggesting covariance in loading between the forelimbs and the hindlimbs. CONCLUSIONS/SIGNIFICANCE: Several features (digital pads, length/width ratio, claw marks) of some ornithopod pes tracks from Las Cerradicas are reminiscent of theropod pedal morphology. This morphological convergence, combined with the shallow nature of the manus tracks, which reduces preservation potential, opens a new window into the interpretation of these tridactyl tracks. Thus, trackmaker assignations during the Jurassic-Cretaceous interval of purported theropod trackways may potentially represent ornithopods. Moreover, the Las Cerradicas trackways are further evidence for quadrupedalism among some basal small- to medium-sized ornithopods from this time interval

    Genome-wide survey of repetitive DNA elements in the button mushroom Agaricus bisporus

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    Repetitive DNA elements are ubiquitous constituents of eukaryotic genomes. The biological roles of these repetitive elements, supposed to impact genome organization and evolution, are not completely elucidated yet. The availability of whole genome sequence offers the opportunity to draw a picture of the genome- wide distribution of these elements and provide insights into potential mechanisms of genome plasticity. The present study uses in silico approaches to describe tandem repeats and transposable elements distribution in the genome of the button mushroom, Agaricus bisporus. Transposable elements comprised 12.43% of the assembled genome, and 66% of them were found clustered in the centromeric or telomeric regions. Methylation of retrotransposon has been demonstrated. A total of 1996 mini-, 4062 micro-, and 37 satellites motifs were identified. The microsatellites appeared widely and evenly spread over the whole genome sequence, whereas the minisatellites were not randomly distributed. Indeed, minisatellites were found to be associated with transposable elements clusters. Telomeres exhibited a specific sequence with a TnAGn signature. A comparison between the two available genome sequences of A. bisporus was also performed and sheds light on the genetic divergence between the two varieties. Beyond their role in genome structure, repeats provide a virtually endless source of molecular markers useful for genetic studies in this cultivated species

    A Palaeoichnological itinerary through the Cenozoic of the Southern Margin of the Pyrenees and the Northern Ebro Basin (Aragón, Northeast Spain)

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    This work aims to bring to light the great wealth of mammal and avian tracksites of the Cenozoic of the southern margin of the Pyrenees and the northern Ebro Basin (Aragon, northeast Spain) by designing a palaeoichnological itinerary that includes the main tracksites. Scientific research in these fields is currently being carried out with very interesting preliminary results, given the poor ichnofossil record in the Palaeogene worldwide. In addition to its scientific importance, however, we want to emphasize the value of this palaeontological heritage as a tourist and educational resource and also the geoconservation work carried out on the tracksites. In some of these sites (Fondota, Sierra de Luna and La Playa Fósil), conservation and adaptation activities have been undertaken over the last few decades. These activities have allowed people to access and visit these tracksites, thus promoting them as socioeconomic assets of this region
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