6,289 research outputs found

    Isotope geochemistry and petrogenesis of peralkaline Middle Miocene ignimbrites from central Sonora: relationship with continental break-up and the birth of the Gulf of California

    Get PDF
    Middle Miocene peralkaline ignimbrites constitute a specific geodynamic marker of the early stage of opening of the Gulf of California, preserved either in central Sonora or the Puertecitos area, in Baja California. Very uniform ages (12-12.5 Ma) obtained on these rocks show that this volcanic episode corresponds to a specific stage in the tectonic evolution of the proto-gulf area. Field observations and slightly different Sr and Nd isotopic signatures support eruptions from several small volume magma batches rather than from a large-volume caldera forming event. Isotopic ratios help to constrain the petrogenesis of the peralkaline liquids by fractional crystallization of transitional basalts in a shallow reservoir, with slight contamination by Precambrian upper crustal material. Less differentiated glomeroporphyritic icelandites erupted at about 11 Ma, mark an increase in the magma production rate and highlight an easier access to the surface, illustrating an advanced stage in the weakening of the continental crust. The tilting of the Middle Tertiary sequences results from a major change in the tectonic regime, from E-W extension giving rise to N-S grabens, to NNW-SSE strike-slip motion that can be related to the transfer of Baja California from North America to the Pacific plate. The location of peralkaline volcanism coincides with the southern edge of the Precambrian crust and the southernmost extension of the California slab window at 12.5 Ma

    Influence of process variables on the kinetic parameters of a Langmuir-Hinshelwood expression for E.coli inactivation during the photocatalytic disinfection of water

    Get PDF
    This research describes the effect of the photocatalyst concentration, irradiation power, concentration of inorganic salts and the initial pH on the three parameters of a Langmuir-Hinshelwood-model: inactivation kinetic constant; k, dimensionless interaction coefficient; K*, and inhibition coefficient; n, which was applied to the photocatalytic disinfection of water with TiO2. In general, there is a qualitative finding in the effects on parameters of some variables since an increase in k was always related to a decrease in K*. Such relation was observed for the amount of TiO2, the irradiation power and the increase in concentration of inorganic salts: NaCl and CaCO3. Moreover, increase in MgSO4 concentration do not cause a tendency of change on the described parameters. As for pH of the reaction media, an increasing effect on k is observed when its value promotes proximity between bacteria and TiO2 particles. Finally, small changes were observed for n with the studied variables, but indeed significant for mathematical fitting. Thus, these findings led to the formulation of a mathematical description of the effects of the most important variables and their interactions on the kinetic parameters. This last hypothesis was validated by comparison of experimental and predicted data with high correlations

    iMole, a web based image retrieval system from biomedical literature

    Get PDF
    iMole is a platform that automatically extracts images and captions from biomedical literature. Images are tagged with terms contained in figure captions by means of a sophisticate text-mining tool. Moreover, iMole allows the user to upload directly their own images within the database and manually tag images by curated dictionary. Using iMole the researchers can develop a proper biomedical image database, storing the images extracted from paper of interest, image found on the web repositories, and their own experimental images. In order to show the functioning of the platform, we used iMole to build a 2DE database. Briefly, tagged 2DE gel images were collected and stored in a searchable 2DE gel database, available to users through an interactive web interface. Images were obtained by automatically parsing 16,608 proteomic publications, which yielded more than 16,500 images. The database can be further expanded by users with images of interest trough a manual uploading process. iMole is available with a preloaded set of 2DE gel data at http://imole.biodigitalvalley.co

    Virtual Reality and Physiotherapy in Post-Stroke Functional Re-Education of the Lower Extremity: A Controlled Clinical Trial on a New Approach

    Get PDF
    Numerous Virtual Reality (VR) systems address post-stroke functional recovery of the lower extremity (LE), most of them with low early applicability due to the gait autonomy they require. The aim of the present study was to evaluate the feasibility of a specific VR treatment and its clinical effect on LE functionality, gait, balance, and trunk control post-stroke. A controlled, prospective, clinical trial was carried out with 20 stroke patients, who were divided into two groups: the first group (VR + CP; n = 10) received combined therapy of 1 h VR and 1 h of conventional physiotherapy (CP) and the second group (CP; n = 10) received 2 h of CP (5 days/week, for 3 weeks). The following pre-post-intervention measuring scales were used: Functional Ambulatory Scale (FAC), Functional Independence Measure (FIM), Fugl-Meyer Assessment (FM), Berg Balance Scale (BBS), and Trunk Control Test (TCT). Only VR + CP showed a significant improvement in FAC. In FIM, CP presented a tendency to significance, whereas VR + CP showed significance. Both groups improved significantly in FM (especially in amplitude/pain in VR + CP and in sensitivity in CP) and in BBS. In TCT, there was a non-significant improvement in both groups. The results indicate that the intervention with VR is a feasible treatment in the post-stroke functional re-education of the LE, with the potential to be an optimal complement of CP

    Porous Titanium surfaces to control bacteria growth: mechanical properties and sulfonated polyetheretherketone coating as antibiofounling approaches

    Get PDF
    Here, titanium porous substrates were fabricated by a space holder technique. The relationship between microstructural characteristics (pore equivalent diameter, mean free-path between pores, roughness and contact surface), mechanical properties (Young’s modulus, yield strength and dynamic micro-hardness) and bacterial behavior are discussed. The bacterial strains evaluated are often found on dental implants: Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa. The colony-forming units increased with the size of the spacer for both types of studied strains. An antibiofouling synthetic coating based on a sulfonated polyetheretherketone polymer revealed an effective chemical surface modification for inhibiting MRSA adhesion and growth. These findings collectively suggest that porous titanium implants designed with a pore size of 100–200 µm can be considered most suitable, assuring the best biomechanical and bifunctional anti-bacterial properties.University of Seville VI Plan Propio de Investigación y Transferencia—US 2018, I.3A

    Silent learning

    Get PDF
    Contains fulltext : 200389.pdf (publisher's version ) (Closed access)We introduce the concept of "silent learning"-the capacity to learn despite neuronal cell-firing being largely absent. This idea emerged from thinking about dendritic computation [1, 2] and examining whether the encoding, expression, and retrieval of hippocampal-dependent memory could be dissociated using the intrahippocampal infusion of pharmacological compounds. We observed that very modest enhancement of GABAergic inhibition with low-dose muscimol blocked both cell-firing and the retrieval of an already-formed memory but left induction of long-term potentiation (LTP) and new spatial memory encoding intact (silent learning). In contrast, blockade of hippocampal NMDA receptors by intrahippocampal D-AP5 impaired both the induction of LTP and encoding but had no effect on memory retrieval. Blockade of AMPA receptors by CNQX impaired excitatory synaptic transmission and cell-firing and both memory encoding and retrieval. Thus, in keeping with the synaptic plasticity and memory hypothesis [3], the hippocampal network can mediate new memory encoding when LTP induction is intact even under conditions in which somatic cell-firing is blocked

    Can Extra Mixing in RGB and AGB Stars Be Attributed to Magnetic Mechanisms?

    Get PDF
    It is known that there must be some weak form of transport (called cool bottom processing, or CBP) acting in low mass RGB and AGB stars, adding nuclei, newly produced near the hydrogen-burning shell, to the convective envelope. We assume that this extra-mixing originates in a stellar dynamo operated by the differential rotation below the envelope, maintaining toroidal magnetic fields near the hydrogen-burning shell. We use a phenomenological approach to the buoyancy of magnetic flux tubes, assuming that they induce matter circulation as needed by CBP models. This establishes requirements on the fields necessary to transport material from zones where some nuclear burning takes place, through the radiative layer, and into the convective envelope. Magnetic field strengths are determined by the transport rates needed by CBP for the model stellar structure of a star of initially 1.5 solar mass, in both the AGB and RGB phases. The field required for the AGB star in the processing zone is B_0 ~ 5x10^6 G; at the base of the convective envelope this yields an intensity B_E < 10^4 G (approximately). For the RGB case, B_0 ~ 5x10^4 to 4x10^5 G, and the corresponding B_E are ~ 450 to 3500 G. These results are consistent with existing observations on AGB stars. They also hint at the basis for high field sources in some planetary nebulae and the very large fields found in some white dwarfs. It is concluded that transport by magnetic buoyancy should be considered as a possible mechanism for extra mixing through the radiative zone, as is required by both stellar observations and the extensive isotopic data on circumstellar condensates found in meteorites.Comment: 26 pages, 4 figures, accepted by Astrophysical Journa

    The gastrointestinal parasite community of wild guanacos (Lama guanicoe) from La Payunia Provincial Reserve, Mendoza, Argentina

    Get PDF
    Los vertebrados silvestres albergan comunidades parasitarias compuestas por varias especies, pero la estructura natural de estas comunidades se está viendo afectada en la actualidad por la fragmentación de hábitat e introducción de especies exóticas. El objetivo de este trabajo fue identificar a las especies de parásitos gastrointestinales presentes en la población migratoria de guanacos silvestres de la Reserva Provincial La Payunia (Mendoza), mediante la identificación de las formas evolutivas presentes en la materia fecal. Se analizaron las heces de 756 individuos, colectadas entre los años 2009 y 2012. La comunidad parasitaria gastrointestinal de esta población de guanacos estuvo compuesta por al menos 11 especies. Los parásitos pertenecieron a 5 especies de nematodes: 2 de Nematodirus, 1 de Trichuris, 1 de Capillaria y 1 de Strongyloides; 1 especie de cestode correspondiente a Moniezia benedeni, y 5 especies de protozoos del género Eimeria (E. lamae, E. alpacae, E. punoensis, E. macusaniensis y E. ivitaensis). Nematodirus spp., Strongyloides sp., y Moniezia benedeni son parásitos propios de rumiantes domésticos y su presencia refleja la susceptibilidad del guanaco, por lo que se recomienda realizar monitoreos parasitológicos periódicos, a fin de poder anticiparse ante incrementos importantes en este tipo de parasitismo en los guanacos silvestres.The parasite community of wild vertebrate hosts is composed of several species, but the natural structure of these communities is currently being affected by habitat fragmentation and the introduction of exotic species. The aim of this work was to identify, through the recognition of immature stages in feces, the gastrointestinal parasite species present in the migratory wild guanaco population from La Payunia Reserve (Mendoza). Feces of 756 individuals, collected between 2009 and 2012, were analyzed. The gastrointestinal parasite community of this guanaco population consisted of at least 11 species. Parasites belonged to 5 nematode species: 2 of Nematodirus, 1 of Trichuris, 1 of Capillaria, and 1 of Strongyloides; 1 cestode species corresponding to Moniezia benedeni; and 5 protozoan species of the genus Eimeria (E. lamae, E. alpacae, E. punoensis, E. macusaniensis, and E. ivitaensis). Nematodirus spp., Strongyloides sp., and the detected spe­cies of Moniezia are typical parasites of livestock, and their presence reflects the guanaco susceptibility to be parasitized by them. We suggest conducting parasitological surveys periodically to be able to anticipate to an important rise in this type of parasitism in wild guanacos.Fil: Moreno, Pablo Gastón. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Shroeder, Natalia M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Taraborelli, Paula Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Gregorio, Pablo Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Carmanchahi, Pablo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Beldomenico, Pablo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentin

    A combination of three distinct trafficking signals mediates axonal targeting and presynaptic clustering of GAD65

    Get PDF
    The signals involved in axonal trafficking and presynaptic clustering are poorly defined. Here we show that targeting of the γ-aminobutyric acid–synthesizing enzyme glutamate decarboxylase 65 (GAD65) to presynaptic clusters is mediated by its palmitoylated 60-aa NH2-terminal domain and that this region can target other soluble proteins and their associated partners to presynaptic termini. A Golgi localization signal in aa 1–23 followed by a membrane anchoring signal upstream of the palmitoylation motif are required for this process and mediate targeting of GAD65 to the cytosolic leaflet of Golgi membranes, an obligatory first step in axonal sorting. Palmitoylation of a third trafficking signal downstream of the membrane anchoring signal is not required for Golgi targeting. However, palmitoylation of cysteines 30 and 45 is critical for post-Golgi trafficking of GAD65 to presynaptic sites and for its relative dendritic exclusion. Reduction of cellular cholesterol levels resulted in the inhibition of presynaptic clustering of palmitoylated GAD65, suggesting that the selective targeting of the protein to presynaptic termini is dependent on sorting to cholesterol-rich membrane microdomains. The palmitoylated NH2-terminal region of GAD65 is the first identified protein region that can target other proteins to presynaptic clusters
    corecore