3,285 research outputs found

    Nouvel Oriocrassatellinae du Pennsylvanien du BrĂ©sil 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 PiauĂ­ Formation, Pennsylvanian of the ParnaĂ­ba 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 crassatellidĂ© Ă  large distribution stratigraphique, bien connu dans les mers Ă©picontinentales en eaux peu profondes, caractĂ©ristique du PalĂ©ozoĂŻque supĂ©rieur. Ce genre apparaĂźt pour la premiĂšre fois dans des dĂ©pĂŽts sĂ©dimentaires du Gondwana, en Australie et en AmĂ©rique du Sud. D’aprĂšs sa distribution spatio-temporelle dans des dĂ©pĂŽts du Mississippien supĂ©rieur, Oriocrassatella serait originaire du dĂ©but du VisĂ©en, ou mĂȘme prĂ©-visĂ©enne. Par la suite, depuis le CarbonifĂšre infĂ©rieur jusqu’au Permien, ce genre a eu une histoire palĂ©obiogĂ©ographique complexe allant de l’hĂ©misphĂšre Sud vers l’hĂ©misphĂšre Nord. Pendant la phase initiale de dispersion Ă  partir du CarbonifĂšre supĂ©rieur jusqu’au Permien infĂ©rieur, ce genre a prospĂ©rĂ© dans un milieu dominĂ© par des eaux froides du Gondwana, suite Ă  la glaciation du PalĂ©ozoĂŻque supĂ©rieur. Les eaux littorales chaudes du Gondwana central et de Laurussia ont Ă©tĂ© colonisĂ©es par Oriocrassatella uniquement durant le Permien infĂ©rieur, parce que ce genre est devenu cosmopolite. Une espĂšce nouvelle, O. piauiensis n. sp., est dĂ©crite de la Formation PiauĂ­ du Pennsylvanien du bassin du ParnaĂ­ba ; elle pourrait reprĂ©senter une premiĂšre adaptation aux eaux chaudes. En outre, et en s’appuyant sur les donnĂ©es disponibles, d’autres espĂšces d’Oriocrassatella se seraient aussi dĂ©finitivement adaptĂ©es Ă  des milieux en eaux chaudes au cours des pĂ©riodes interglaciaires du Pennsylvanien tardif, car des barriĂšres climatiques ont disparu, favorisant des Ă©changes de faune avec dispersion des larves, et migration du sud vers le nord le long des bordures est du Gondwana et de la PalĂ©otĂ©thys.Fil: Anelli, Luiz E.. Universidade de Sao Paulo; BrasilFil: SimĂ”es, Marcello G.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Gonzalez, Carlos Roberto. FundaciĂłn Miguel Lillo; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - TucumĂĄn; ArgentinaFil: Souza, Paulo A.. Universidade Federal do Rio Grande do Sul; Brasi

    Arsenic movement and fractionation in agricultural soils which received wastewater from an adjacent industrial site for 50 years

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    Arsenic (As) is an element with important environmental and human health implications due to its toxic properties. It is naturally occurring since it is contained in minerals, but it can also be enriched and distributed in the environment by anthropogenic activities. This paper reports on the historic As contamination of agricultural soils in one of the most important national relevance site for contamination in Italy, the so-called SIN Brescia-Caffaro, in the city of Brescia, northern Italy. These agricultural areas received As through the use of irrigation waters from wastewater coming from a factory of As-based pesticides (lead and calcium arsenates, sodium arsenite). Pesticide production started in 1920 and ended in the '70. Concentrations in the areas are generally beyond the legal threshold values for different soil uses and are up to >200 mg/kg. Arsenic contamination was studied to assess the long-time trend and the dynamics related to the vertical movement of As down to 1 m depth and its horizontal diffusion with surface irrigation in the entire field. Arsenic fractionation analysis (solid phase speciation by sequential extraction procedure) was also performed on samples collected from these areas and employed in greenhouse experiments with several plant species to evaluate the long-term contamination and the role of plant species in modifying As availability in soil. The results of this work can help in the evaluation of the conditions controlling the vertical transfer of As towards surface aquifers, the bioaccumulation likelihood in the agricultural food chain and the selection of sustainable remediation techniques such as phytoextraction

    Epitranscriptomics in normal and malignant hematopoiesis

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    Epitranscriptomics analyze the biochemical modifications borne by RNA and their downstream influence. From this point of view, epitranscriptomics represent a new layer for the control of genetic information and can affect a variety of molecular processes including the cell cycle and the differentiation. In physiological conditions, hematopoiesis is a tightly regulated process that produces differentiated blood cells starting from hematopoietic stem cells. Alteration of this process can occur at different levels in the pathway that leads from the genetic information to the phenotypic manifestation producing malignant hematopoiesis. This review focuses on the role of epitranscriptomic events that are known to be implicated in normal and malignant hematopoiesis, opening a new pathophysiological and therapeutic scenario. Moreover, an evolutionary vision of this mechanism will be provided

    Effect of oral consumption of capsules containing Lactobacillus paracasei LPC-S01 on the vaginal microbiota of healthy adult women: a randomized, placebo-controlled, double-blind crossover study

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    Oral consumption of probiotics is practical and can be an effective solution to preserve vaginal eubiosis. Here, we studied the ability of orally administered Lactobacillus paracasei LPC-S01 (DSM 26760) to affect the composition of the vaginal microbiota and colonize the vaginal mucosa in nondiseased adult women. A total of 40 volunteers took oral probiotic (24 billion CFU) or placebo capsules daily for 4 weeks, and after a 4-week washout, they switched to placebo or probiotic capsules according to the crossover design. A total of 23 volunteers completed the study according to the protocol. Before and after capsule ingestion, vaginal swabs were collected for qPCR quantification to detect L. paracasei LPC-S01 and for 16S rRNA gene sequencing. Vaginal swabs were grouped according to their bacterial taxonomic structure into nine community state types (CSTs), four of which were dominated by lactobacilli. Lactobacillus paracasei LPC-S01 was detected in the vagina of two participants. Statistical modeling (including linear mixed-effects model analysis) demonstrated that daily intake of probiotic capsules reduced the relative abundance of Gardnerella spp. Quantitative PCR with Gardnerella vaginalis primers confirmed this result. Considering the pathogenic nature of G. vaginalis, these results suggest a potential positive effect of this probiotic capsule on the vaginal microbial ecosystem

    Development of high grade seamless pipes for deepwater application by metallurgical design

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    New solutions for the metallurgical design of high performance quenched and tempered (Q&T) seamless pipes of high grades from X65 up to X80 were found throughout a systematic work involving metallurgical modelling, laboratory tests, pilot and industrial trials. Both linepipes and risers for deepwater offshore fields such as Gulf of Mexico were considered. The target microstructure in the asquenched condition has been identified as refined low-C bainite/martensite matrix (> 70%). This is promoted through the control of austenite grain growth during the heating stage (austenitization before quenching), proper alloy additions and through a very effective quenching. Promising low-alloy steels and suitable quenching and tempering conditions identified by metallurgical modelling were verified by laboratory heats (80 kg ingots) that were processed at a pilot scale and submitted to microstructural examination and mechanical testing. The best solutions were used in preliminary industrial trials, also utilised for a fine tuning. The Ni-Cr-Mo-Nb-V alloy system showed very interesting combinations of strength-toughness and field weldability, suitable for the production of heavy wall X65 grade linepipes for sour service and X80 top tension risers

    A didactic experiment to measure the angular correlation between

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    A didactic experiment carried out by a group of Physics masters’ students at Bari University is presented. The purpose was the study of the angular correlation between the two gamma rays of 1.17 MeV and 1.33 MeV emitted in typical 60Co decays by means of two NaI(Tl) scintillators equipped with photomultiplier tubes read out by a digital oscilloscope. Several runs were performed with the Co source at different angles between the two scintillators. Additional runs were performed removing the source, to study the backgrounds from cosmic rays and from gamma rays emitted by the radioactive isotopes 208Tl and 40K. Our results showed that the signal rate changes with the angular separation in agreement with the theoretical expectations by Hamilton dating back to 1940 and with recent measurements documented in the literature. Students learned to plan and set up an experiment, to take data and to perform basic analysis. Care was taken to understand the limits of our experimental apparatus and possible improvements

    Proton-proton elastic scattering at the LHC energy of {\surd} = 7 TeV

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    Proton-proton elastic scattering has been measured by the TOTEM experiment at the CERN Large Hadron Collider at {\surd}s = 7 TeV in dedicated runs with the Roman Pot detectors placed as close as seven times the transverse beam size (sbeam) from the outgoing beams. After careful study of the accelerator optics and the detector alignment, |t|, the square of four-momentum transferred in the elastic scattering process, has been determined with an uncertainty of d t = 0.1GeV p|t|. In this letter, first results of the differential cross section are presented covering a |t|-range from 0.36 to 2.5GeV2. The differential cross-section in the range 0.36 < |t| < 0.47 GeV2 is described by an exponential with a slope parameter B = (23.6{\pm}0.5stat {\pm}0.4syst)GeV-2, followed by a significant diffractive minimum at |t| = (0.53{\pm}0.01stat{\pm}0.01syst)GeV2. For |t|-values larger than ~ 1.5GeV2, the cross-section exhibits a power law behaviour with an exponent of -7.8_\pm} 0.3stat{\pm}0.1syst. When compared to predictions based on the different available models, the data show a strong discriminative power despite the small t-range covered.Comment: 12pages, 5 figures, CERN preprin

    Measurement of the front-end dead-time of the LHCb muon detector and evaluation of its contribution to the muon detection inefficiency

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    A method is described which allows to deduce the dead-time of the front-end electronics of the LHCb muon detector from a series of measurements performed at different luminosities at a bunch-crossing rate of 20 MHz. The measured values of the dead-time range from 70 ns to 100 ns. These results allow to estimate the performance of the muon detector at the future bunch-crossing rate of 40 MHz and at higher luminosity
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