69 research outputs found

    Reptilia, Chelonii, Chelidae, Phrynops geoffroanus Schweigger, 1812 and Mesoclemmys vanderhaegei (Bour, 1973): distribution extension, new country record, and new province records in Argentina

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    The Chelonii is currently represented in Argentina by 14 species of 10 genera, belonging to six families (Richard and Waller 2000). Although several authors have addressed the study of Argentinean turtle species (e.g. Freiberg 1938; 1977; Cei 1993; Cabrera 1998; Richard 1999; Richard and Waller 2000), the knowledge about natural history and geographic distribution of some species is still fragmentary. One of these poorly known species is the freshwater turtle Phrynops geoffroanus. This turtle is widely distributed in South America eastern to the Andes, in the Orinoco, Amazonas, SĂŁo Francisco, and ParanĂĄ rivers basins (Iverson 1992; Souza 2005). Bertoni (1925) recorded the presence of P. geoffroanus (as Hydraspis geoffroyana) at the locality of Puerto Bertoni in the High ParanĂĄ River, Paraguay, and suggested that it was likely to occur in northeastern Argentina, in the province of Misiones; subsequently Freiberg (1938; 1970; 1977) reported the presence of P. geoffroanus in the province of Misiones. Rhodin and Mittermeier (1983) described Phrynops williamsi and mentioned the presence of this species in the Misiones, within the distribution range of P. geoffroanus. This was accepted by other authors, who suggested that P. geoffroanus was present in Argentina (Pritchard and Trebbau 1984; Ernst and Barbour 1989; Iverson 1992; Fritz and Havas 2007). Nevertheless, most of recent studies about the Argentinean turtle fauna excluded P. geoffroanus from it, based on the absence of specimens in collections, and also because previous reports were considered to be misidentification records of P. williamsi (Waller and Chebez 1987; Richard et al. 1990; Cei 1993; Cabrera 1998; Richard 1999; Richard and Waller 2000).Fil: Baldo, Juan Diego. Universidad Nacional de Misiones; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; ArgentinaFil: MartĂ­nez, Pablo. Universidad Nacional de Misiones; ArgentinaFil: Boeris, Juan MartĂ­n. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; Argentina. Universidad Nacional de Misiones; ArgentinaFil: Giraudo, Alejandro Raul. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Santa Fe. Instituto Nacional de LimnologĂ­a. Universidad Nacional del Litoral. Instituto Nacional de LimnologĂ­a; Argentin

    La teorĂ­a de los "ratios" aplicada a la AdministraciĂłn

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    Ku-0063794 is a specific inhibitor of the mammalian target of rapamycin (mTOR)

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    mTOR (mammalian target of rapamycin) stimulates cell growth by phosphorylating and promoting activation of AGC (protein kinase A/protein kinase G/protein kinase C) family kinases such as Akt (protein kinase B), S6K (p70 ribosomal S6 kinase) and SGK (serum and glucocorticoid protein kinase). mTORC1 (mTOR complex-1) phosphorylates the hydrophobic motif of S6K, whereas mTORC2 phosphorylates the hydrophobic motif of Akt and SGK. In the present paper we describe the small molecule Ku-0063794, which inhibits both mTORC1 and mTORC2 with an IC50 of ∌10 nM, but does not suppress the activity of 76 other protein kinases or seven lipid kinases, including Class 1 PI3Ks (phosphoinositide 3-kinases) at 1000-fold higher concentrations. Ku-0063794 is cell permeant, suppresses activation and hydrophobic motif phosphorylation of Akt, S6K and SGK, but not RSK (ribosomal S6 kinase), an AGC kinase not regulated by mTOR. Ku-0063794 also inhibited phosphorylation of the T-loop Thr308 residue of Akt phosphorylated by PDK1 (3-phosphoinositide-dependent protein kinase-1). We interpret this as implying phosphorylation of Ser473 promotes phosphorylation of Thr308 and/or induces a conformational change that protects Thr308 from dephosphorylation. In contrast, Ku-0063794 does not affect Thr308 phosphorylation in fibroblasts lacking essential mTORC2 subunits, suggesting that signalling processes have adapted to enable Thr308 phosphorylation to occur in the absence of Ser473 phosphorylation. We found that Ku-0063794 induced a much greater dephosphorylation of the mTORC1 substrate 4E-BP1 (eukaryotic initiation factor 4E-binding protein 1) than rapamycin, even in mTORC2-deficient cells, suggesting a form of mTOR distinct from mTORC1, or mTORC2 phosphorylates 4E-BP1. Ku-0063794 also suppressed cell growth and induced a G1-cell-cycle arrest. Our results indicate that Ku-0063794 will be useful in delineating the physiological roles of mTOR and may have utility in treatment of cancers in which this pathway is inappropriately activated

    Centrality evolution of the charged-particle pseudorapidity density over a broad pseudorapidity range in Pb-Pb collisions at root s(NN)=2.76TeV

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    Amphibian parasites of the Order Dermocystida (Ichthyosporea): current knowledge, taxonomic review and new records from Brazil

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    Amphibian parasites of the Order Dermocystida (Ichthyosporea) are widespread pathogens known mainly from Europe and North America, which cause primarily a disease of skin and subcutaneous tissue in their hosts. The taxonomy of these organisms has been problematic given their conserved morphology, similar clinical disease and pathology. Currently recognized taxa belong to the three closely related genera, Amphibiocystidium, Amphibiothecum, and Rhinosporidium, whereas species of Dermocystidium and Sphaerothecum destruens include fish parasites. Here, we review the taxonomy of Dermocystida based on a molecular phylogenetic analysis, principally of amphibian parasites, including DNA sequences obtained from amphibian hosts collected in the central-eastern region of South America. A new taxonomic arrangement is proposed, which includes the designation of type material for Dermocystidium pusula, synonymization of Amphibiothecum with Dermocystidium, and the restriction of Amphibiocystidium to its type species A. ranae. We also review the taxonomic status of Dermosporidium hylarum until the present work included in the synonymy of the human and animal pathogen R. seeberi, and considered herein as a valid taxon, however. In addition, a new species of Sphaerothecum parasitic to amphibians is described, being the first record of this genus in the southern hemisphere and in an amphibian host.Fil: Borteiro, Claudio. Universidad de la RepĂșblica; Uruguay. Museo Nacional de Historia Natural; UruguayFil: Baldo, Juan Diego. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Nordeste. Instituto de BiologĂ­a Subtropical. Universidad Nacional de Misiones. Instituto de BiologĂ­a Subtropical; ArgentinaFil: Maronna, Maximiliano M.. Universidade de Sao Paulo; BrasilFil: Pontes BaĂȘta Da Costa, DĂ©lio. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Sabbag, Ariadne Fares. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Kolenc, Francisco. Museo Nacional de Historia Natural; UruguayFil: Debat, Claudio MartĂ­nez. Universidad de la RepĂșblica; UruguayFil: Haddad, CĂ©lio F. B.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Cruz, Juan Carlos. Universidad de la RepĂșblica; UruguayFil: Verdes, JosĂ© Manuel. Universidad de la RepĂșblica; UruguayFil: Ubilla, MartĂ­n. Universidad de la RepĂșblica; Urugua

    Small variations in soil properties control fire-induced water repellency.

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    Fire induced soil water repellency (WR) is controlled by many different factors (temperature reached, amount and type of fuel, etc.). Soil properties may determine the occurrence and intensity of this property in burned soils. The objectives of this paper are to make advances in the study of soil properties as key factors controlling the behaviour of fire-induced WR, and to study the impact of pre-fire SOM content and SOM quality in fire-induced soil WR. In this research, experimental laboratory burnings were carried out using soil samples from different sites with different lithologies, soil types and plant species. Soil samples from the same site differ only in quantity and quality of soil organic matter, as they were collected from under different plant species. All soil samples were heated in a muffle furnace at 200, 250, 300 and 350 ÂșC without the addition of any fuel load. WR was measured using the water drop penetration time test (WDPT). The results showed significant differences between soil types and plant species, indicating that small differences in soil properties may act as key factors controlling the development and persistence of WR reached, with burned soil samples ranging from wettable to extremely water repellent. The main soil property controlling the response was texture, specifically sand content. The quality of organic matter was also observed to have an effect, since soil samples from the same site with similar organic matter contents, but collected from beneath different plant species, showed different WR values after burning.A repelĂȘncia Ă  ĂĄgua (WR) induzida no solo pelo fogo Ă© uma propriedade controlada por diversos fatores (temperatura atingida, quantidade e tipo de combustĂ­vel, etc.). Algumas propriedades podem determinar a presença e intensidade da WR nos solos afetados pelo fogo. O objetivo deste artigo Ă© demonstrar os Ășltimos avanços no estudo das propriedades do solo, como factores chave, que controlam o comportamento da hidrofobicidade induzida pelo fogo, o impacto do conteĂșdo de matĂ©ria orgĂąnica prĂ©-fogo e a qualidade da matĂ©ria orgĂąnica em solos afetados por repelĂȘncia pĂłs-incĂȘndio. Neste estudo, foram realizadas queimadas controladas em laboratĂłrio, utilizando amostras de solo de locais com diferentes substratos litolĂłgicos e com diferentes tipos de solo, colonizados por diferentes espĂ©cies vegetais. As amostras recolhidas em diferentes locais diferem nalgumas propriedades do solo, enquanto as amostras de solo recolhidas no mesmo local apenas diferem na quantidade e qualidade da matĂ©ria orgĂąnica, dado que foram recolhidas em ĂĄreas colonizadas por diferentes espĂ©cies de plantas. Todas as amostras foram submetidas Ă s temperaturas de 200, 250, 300 e 350 °C num forno. A WR foi medida atravĂ©s do teste da gota de ĂĄgua (WDPT). Os resultados mostraram diferenças significativas entre os tipos de solos e plantas estudadas. Observaram-se pequenas diferenças em algumas propriedades do solo, que podem atuar como fatores-chave que controlam o desenvolvimento e persistĂȘncia da WR nos solos queimados, que variam entre o hidrofĂ­lico e o extremamente repelente Ă  ĂĄgua. A propriedade que mais influencia o comportamento da WR Ă© a textura, especialmente o teor em areia. Por outro lado, observou-se que a qualidade da matĂ©ria orgĂąnica tambĂ©m afetou a WR, dado que em amostras de solo recolhidas no mesmo local e com conteĂșdo em matĂ©ria orgĂąnica semelhante, mas recolhidas em solos colonizados por diferentes espĂ©cies de plantas, mostraram valores muito diferentes de repelĂȘncia Ă  ĂĄgua apĂłs a queimada.La repelencia al agua (WR) inducida por el fuego es una propiedad controlada por muchos factores diferentes (temperaturas alcanzadas, cantidad y tipo de combustible, etc.). Algunas propiedades del suelo pueden determinar la presencia y la intensidad de esta propiedad en los suelos quemados. Los objetivos principales son: avanzar en el estudio de la influencia de algunas propiedades clave en el control del comportamiento de la WR en suelos quemados, asĂ­ como estudiar la influencia de la cantidad y la calidad de la materia orgĂĄnica del suelo en su desarrollo cuando es afectada por el calentamiento. En Ă©ste estudio, hemos realizado quemas controladas en laboratorio utilizando muestras de suelo de diferentes sitios con litologĂ­as y tipos de suelos diferentes y recogidas bajo distintas especies vegetales. Las muestras recogidas en diferentes sitios difieren en algunas propiedades del suelo, mientras que las muestras de suelo tomadas del mismo sitio sĂłlo se diferencian en la cantidad y la calidad de la materia orgĂĄnica del suelo, ya que se recogieron bajo distintas especies de plantas. Todas las muestras de suelo se calentaron en horno de mufla a 200, 250, 300 y 350 ÂșC. La repelencia al agua se midiĂł mediante el test del tiempo de penetraciĂłn de la gota de agua (WDPT). Los resultados mostraron diferencias significativas entre los tipos de suelos y especies vegetales, y se comprobĂł que pequeñas diferencias en algunas propiedades del suelo pueden actuar como factores clave controlando el desarrollo y persistencia de la repelencia al agua, con muestras de suelo quemadas que variaban entre hidrofĂ­licas a extremadamente repelentes al agua. La propiedad que principalmente controlĂł el comportamiento de la repelencia al calentamiento fue la textura y mĂĄs concretamente el contenido de arena. Por otro lado se observĂł que la calidad de la materia orgĂĄnica tambiĂ©n afecta, ya que muestras de suelo de mismo sitio y con contenido de materia orgĂĄnica similar, pero tomadas bajo diferentes especies vegetales mostraron valores muy diferentes de repelencia al agua tras la quema

    Measurement of electrons from beauty-hadron decays in p–Pb collisions at √sNN = 5.02 TeV and Pb–Pb collisions at √sNN = 2.76 TeV

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    The production of beauty hadrons was measured via semi-leptonic decays at mid-rapidity with the ALICE detector at the LHC in the transverse momentum interval 1<pT<8 GeV/c in minimum-bias p-Pb collisions at sNN−−−√=5.02 TeV and in 1.3<pT<8 GeV/c in the 20% most central Pb-Pb collisions at sNN−−−√=2.76 TeV. The pp reference spectra at s√=5.02 TeV and s√=2.76 TeV, needed for the calculation of the nuclear modification factors RpPb and RPbPb, were obtained by a pQCD-driven scaling of the cross section of electrons from beauty-hadron decays measured at s√=7 TeV. In the pT interval 3<pT<8 GeV/c a suppression of the yield of electrons from beauty-hadron decays is observed in Pb-Pb compared to pp collisions. Towards lower pT, the RPbPb values increase with large systematic uncertainties. The RpPb is consistent with unity within systematic uncertainties and is well described by theoretical calculations that include cold nuclear matter effects in p-Pb collisions. The measured RpPb and these calculations indicate that cold nuclear matter effects are small at high transverse momentum also in Pb-Pb collisions. Therefore, the observed reduction of RPbPb below unity at high pT may be ascribed to an effect of the hot and dense medium formed in Pb-Pb collisions

    Anomalous evolution of the near-side jet peak shape in Pb–Pb collisions at √sNN = 2.76 TeV

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    The measurement of two-particle angular correlations is a powerful tool to study jet quenching in a pT region inaccessible by direct jet identification. In these measurements pseudorapidity (Δη) and azimuthal (Δφ) differences are used to extract the shape of the near-side peak formed by particles associated to a higher pT trigger particle (1<pT,trig< 8 GeV/c). A combined fit of the near-side peak and long-range correlations is applied to the data allowing the extraction of the centrality evolution of the peak shape in Pb-Pb collisions at sNN−−−√ = 2.76 TeV. A significant broadening of the peak in the Δη direction at low pT is found from peripheral to central collisions, which vanishes above 4 GeV/c, while in the Δφ direction the peak is almost independent of centrality. For the 10% most central collisions and 1<pT,assoc< 2 GeV/c, 1<pT,trig< 3 GeV/c a novel feature is observed: a depletion develops around the centre of the peak. The results are compared to pp collisions at the same centre of mass energy and to AMPT model simulations. The comparison to the investigated models suggests that the broadening and the development of the depletion is connected to the strength of radial and longitudinal flow

    Measurement of an excess in the yield of J/ψ at very low pT in Pb–Pb collisions at √sNN = 2.76 TeV

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    We report on the first measurement of an excess in the yield of J/ψ at very low transverse momentum (pT<0.3 GeV/c) in peripheral hadronic Pb-Pb collisions at sNN−−−√ = 2.76 TeV, performed by ALICE at the CERN LHC. Remarkably, the measured nuclear modification factor (RAA) of J/ψ in the rapidity range 2.5<y<4 reaches about 7 (2) in the pT range 0-0.3 GeV/c in the 70-90% (50-70%) centrality class. The J/ψ production cross section associated with the observed excess is obtained under the hypothesis that coherent photoproduction of J/ψ is the underlying physics mechanism. If confirmed, the observation of J/ψ coherent photoproduction in Pb-Pb collisions at impact parameters smaller than twice the nuclear radius opens new theoretical and experimental challenges and opportunities. In particular, coherent photoproduction accompanying hadronic collisions may provide insight into the dynamics of photoproduction and nuclear reactions, as well as become a novel probe of the Quark-Gluon Plasma
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