1,780 research outputs found

    Balance or imbalance? Paleoecology of the Pleistocene of North and South America

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    In recent years, the validity of the model proposed by Damuth about the paleoecology of past and present mammalian faunas has been addressed. In previous works such model had been applied to the fauna of Rancho La Brea (North American late Pleistocene), Venta Micena (European early Pleistocene) and to other faunas in South America. In the case of Rancho La Brea, the model had shown that it behaved as expected, i.e., keeping the balance between number of herbivorous species and primary productivity, and between number of carnivore species and secondary productivity. In other words, that the primary productivity was enough to feed the herbivores in the community, and that the secondary productivity (which is the meat available for carnivores to eat) was fully consumed by the carnivores, as in modern, actualistic examples of communities with large mammals. In the South American Lujanian Age (late Pleistocene-early Holocene), an imbalance was proposed, namely that the herbivores did not have enough food to eat according to reconstructions of their environment, and, on the other hand, that the carnivores had too much. In this work twenty six faunas from North America were studied, as well as fifteen from South America. For their study the same model and equations were applied. The results showed that those North American faunas that had number of mammalian species large enough to infer that the community was well represented were balanced, while those with few species or a low number of carnivores were not. In addition, all the Pleistocene South American faunas from diverse origins in the subcontinent were imbalanced. A possible explanation already stated was that in South America there was a great diversity of xenarthrans. In the North American faunas, such diversity was not high, and also not higher than that of any other order of mammals.Sesiones libresFacultad de Ciencias Naturales y Muse

    Cloud point extraction based on non-ionic surfactants: An ecofriendly tool for recovering papain from papaya latex

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    The potential use of cloud point extraction with aqueous micellar two-phase systems (AMTPS), formed by the non-ionic biodegradable surfactants Triton X-114 (TX-114) and Genapol X-080 (GX-080), to recover papain (PAP) from fresh papaya latex was evaluated. Binodal curves obtained for both surfactants, in absence and presence of PAP, showed cloud points below 40 °C, the PAP presence slightly favoring the phase separation phenomenon. Partitioning experiments showed that PAP migrated toward the micelle-poor phase independently of the surfactant and the working temperature assayed, this behavior being consistent with this enzyme hydrophilic character. PAP recoveries of over 60% in the poor-micelle phase were obtained when partitioned fresh papaya latex in both surfactant-based AMTPS. TX-114 systems (4.00% w/w, 33 °C) allowed recovering 66% of PAP with a purification factor of 4.6. On GX-080 systems (4.00% w/w, 42 °C) a yield of 78% PAP and a purification factor of 3.7 were achieved. This AMTPS also allowed the separation of PAP from reducing sugars present in papaya latex. These results show that TX-114 and GX-080-based AMTPS could be potentially used as simple and economical tools at recovering PAP from papaya latex.Fil: DI GIACOMO, MELISA. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Procesos Biotecnológicos y Químicos Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Procesos Biotecnológicos y Químicos Rosario; ArgentinaFil: Bertoni, Fernando Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Procesos Biotecnológicos y Químicos Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Procesos Biotecnológicos y Químicos Rosario; ArgentinaFil: Rocha, María Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Procesos Biotecnológicos y Químicos Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Procesos Biotecnológicos y Químicos Rosario; ArgentinaFil: Nerli, Bibiana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Procesos Biotecnológicos y Químicos Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Procesos Biotecnológicos y Químicos Rosario; ArgentinaFil: Rodriguez, Fernanda Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Procesos Biotecnológicos y Químicos Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Procesos Biotecnológicos y Químicos Rosario; Argentin

    Megafauna en el Arroyo del Vizcaíno

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    Obra en 3 volúmenes.Este libro fue realizado por el equipo del Laboratorio de Paleobiología de la Facultad de Ciencias de la Universidad de la República con motivo de la conmemoración de los 10 años de las primeras excavaciones realizadas por el equipo en el sitio Arroyo del Vizcaíno y en la colección del Servicio Académico Universitario y Centro de Estudio Paleontológicos (SAUCE-P).El sitio paleontológico del Arroyo del Vizcaíno, cerca de la localidad de Sauce, Uruguay, cuenta una historia de mamíferos gigantes ya desaparecidos, con el particular agregado de posible evidencia de una muy antigua presencia humana. Una ventana escondida en el fondo de un arroyo por 30.000 años, que a través de miles de fósiles nos permite asomarnos y descubrir un fragmento del pasado profundo. Los tres volúmenes de esta publicación tratan de distintas áreas (la historia, la excavación, la investigación, la divulgación, la conservación y la fauna) del trabajo realizado en el sitio por el equipo del Laboratorio de Paleobiología de la Facultad de Ciencias de la Universidad de la RepúblicaV1: Descubrir, excavar, interpretar.-- V2: Conservar, investigar, compartir. -- V3: Corazas, garras y diente

    Conocimiento presente para la sociedad: la mirada de la paleontología en un caso de vínculo con la comunidad

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    En este artículo damos a conocer diversas actividades de vínculo con la comunidad a partir del conocimiento científico relacionado con el yacimiento del Arroyo del Vizcaíno en Uruguay. Este sitio, ubicado en las afueras de la ciudad de Sauce, presenta miles de huesos fósiles de mamíferos gigantes extintos y evidencias de posible presencia humana. Desde su descubrimiento, la comunidad local estuvo involucrada en la colecta y conser- vación del material, una feliz circunstancia a la que se sumó nuestro equipo aportando el saber disciplinario y la misma vocación de tender puentes entre la academia y la sociedad a través del cuidado de ese patrimonio, de diversas actividades presenciales, recursos vir- tuales y otros emprendimientos

    Conocimiento presente para la sociedad: la mirada de la paleontología en un caso de vínculo con la comunidad

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    En este artículo damos a conocer diversas actividades de vínculo con la comunidad a partir del conocimiento científico relacionado con el yacimiento del Arroyo del Vizcaíno en Uruguay. Este sitio, ubicado en las afueras de la ciudad de Sauce, presenta miles de huesos fósiles de mamíferos gigantes extintos y evidencias de posible presencia humana. Desde su descubrimiento, la comunidad local estuvo involucrada en la colecta y conservación del material, una feliz circunstancia a la que se sumó nuestro equipo aportando el saber disciplinario y la misma vocación de tender puentes entre la academia y la sociedad a través del cuidado de ese patrimonio, de diversas actividades presenciales, recursos virtuales y otros emprendimientos.In this article, we present various activities shared with the community based on scientific knowledge related to the Arroyo del Vizcaíno site in Uruguay. This site, located on the outskirts of the city of Sauce, presents thousands of fossil bones of extinct giant mammals and evidence of possible human presence. Since its discovery, the local community has been involved in the collection and conservation of the material, a happy circumstance to which our team joined, contributing disciplinary knowledge and the same vocation of building bridges between the academy and society through the care of that heritage, of diverse presencial activities, virtual resources and other endeavours

    Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

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    BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

    Sigh in patients with acute hypoxemic respiratory failure and acute respiratory distress syndrome: the PROTECTION pilot randomized clinical trial

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    Background: Sigh is a cyclic brief recruitment manoeuvre: previous physiological studies showed that its use could be an interesting addition to pressure support ventilation to improve lung elastance, decrease regional heterogeneity and increase release of surfactant. Research question: Is the clinical application of sigh during pressure support ventilation (PSV) feasible? Study design and methods: We conducted a multi-center non-inferiority randomized clinical trial on adult intubated patients with acute hypoxemic respiratory failure or acute respiratory distress syndrome undergoing PSV. Patients were randomized to the No Sigh group and treated by PSV alone, or to the Sigh group, treated by PSV plus sigh (increase of airway pressure to 30 cmH2Ofor 3 seconds once per minute) until day 28 or death or successful spontaneous breathing trial. The primary endpoint of the study was feasibility, assessed as non-inferiority (5% tolerance) in the proportion of patients failing assisted ventilation. Secondary outcomes included safety, physiological parameters in the first week from randomization, 28-day mortality and ventilator-free days. Results: Two-hundred fifty-eight patients (31% women; median age 65 [54-75] years) were enrolled. In the Sigh group, 23% of patients failed to remain on assisted ventilation vs. 30% in the No Sigh group (absolute difference -7%, 95%CI -18% to 4%; p=0.015 for non-inferiority). Adverse events occurred in 12% vs. 13% in Sigh vs. No Sigh (p=0.852). Oxygenation was improved while tidal volume, respiratory rate and corrected minute ventilation were lower over the first 7 days from randomization in Sigh vs. No Sigh. There was no significant difference in terms of mortality (16% vs. 21%, p=0.342) and ventilator-free days (22 [7-26] vs. 22 [3-25] days, p=0.300) for Sigh vs. No Sigh. Interpretation: Among hypoxemic intubated ICU patients, application of sigh was feasible and without increased risk

    Identification of heavy-flavour jets with the CMS detector in pp collisions at 13 TeV

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    Many measurements and searches for physics beyond the standard model at the LHC rely on the efficient identification of heavy-flavour jets, i.e. jets originating from bottom or charm quarks. In this paper, the discriminating variables and the algorithms used for heavy-flavour jet identification during the first years of operation of the CMS experiment in proton-proton collisions at a centre-of-mass energy of 13 TeV, are presented. Heavy-flavour jet identification algorithms have been improved compared to those used previously at centre-of-mass energies of 7 and 8 TeV. For jets with transverse momenta in the range expected in simulated tt\mathrm{t}\overline{\mathrm{t}} events, these new developments result in an efficiency of 68% for the correct identification of a b jet for a probability of 1% of misidentifying a light-flavour jet. The improvement in relative efficiency at this misidentification probability is about 15%, compared to previous CMS algorithms. In addition, for the first time algorithms have been developed to identify jets containing two b hadrons in Lorentz-boosted event topologies, as well as to tag c jets. The large data sample recorded in 2016 at a centre-of-mass energy of 13 TeV has also allowed the development of new methods to measure the efficiency and misidentification probability of heavy-flavour jet identification algorithms. The heavy-flavour jet identification efficiency is measured with a precision of a few per cent at moderate jet transverse momenta (between 30 and 300 GeV) and about 5% at the highest jet transverse momenta (between 500 and 1000 GeV)

    Search for heavy resonances decaying to a top quark and a bottom quark in the lepton+jets final state in proton–proton collisions at 13 TeV

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