119 research outputs found

    Modulatory effects of ghrelin on sperm quality alterations induced by a fructose-enriched diet

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    The objectives of this study were: 1) to evaluate the effects of a fructose enriched diet (FED) on rat3 sperm quality, epididymal function (i.e. oxidative stress and alpha-glucosidase expression) and4 testosterone concentrations; 2) to determine if the administration of ghrelin (Ghrl), reverses the5 effects induced by FED.6 After validating the protocol as an inductor of metabolic syndrome like-symptoms, adult male rats7 were assigned to one of the following treatments for 8 weeks: FED=10% fructose enriched in water8 (v/v); FED+Ghrl=fructose enriched diet plus Ghrl (6 nmol/animal/day, s.c.) from week 6 to 8; or9 C=water without fructose (n=5-10 animals/group).10 FED significantly decreased sperm concentration and motile sperm count/ml vs C (FED:19.0±1.6x106sperm/ml and 834.6±137.0, respectively vs C: 25.8±2.8x10611 and 1300.4±202.4,respectively; p<0.05); ghrelin injection reversed this negative effect (23.5±1.6x10612 sperm/ml and13 1381.7±71.3 respectively). FED resulted in hypogonadism, but Ghrl could not normalize testosterone14 concentrations (C: 1.4±0.1 ng/ml vs FED: 0.8±0.2 ng/ml and FED+Ghrl: 0.6±0.2 ng/ml ;p<0.05).15 Ghrelin did not reverse metabolic abnormalities secondary to FED. FED did not alter epididymal16 expression of antioxidants enzymes (superoxido-dismutase, catalase and glutathione peroxidases ?17 Gpx-). Nevertheless, FED+Ghrl significantly increased the expression of Gpx3 (FED+Ghrl:18 3.47±0.48 vs FED: 0.69±0.28 and C: 1.00±0.14; p<0.05). The expression of neutral alpha19 glucosidase, which is a marker of epididymal function, did not differ between treatments.20 In conclusion, the administration of Ghrl modulated the negative effects of FED on sperm quality,21 possibly by an epididymal increase in Gpx3 expression. However, Ghrl could not neither normalize22 the metabolism of FED animals, nor reverse hypogonadism.Fil: Ramirez, Nicolás David. Universidad Nacional de Córdoba. Facultad de Medicina. Departamento de Fisiología Humana y Física Biomédica. Cátedra de Fisiología Humana; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Ciencias de la Salud. Universidad Nacional de Córdoba. Instituto de Investigaciones en Ciencias de la Salud; ArgentinaFil: Luque, Eugenia Mercedes. Universidad Nacional de Córdoba. Facultad de Medicina. Departamento de Fisiología Humana y Física Biomédica. Cátedra de Fisiología Humana; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Ciencias de la Salud. Universidad Nacional de Córdoba. Instituto de Investigaciones en Ciencias de la Salud; ArgentinaFil: Jones, Xaviar Michael. Universidad Nacional de Córdoba. Facultad de Medicina. Departamento de Fisiología Humana y Física Biomédica. Cátedra de Fisiología Humana; ArgentinaFil: Torres, Pedro Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Ciencias de la Salud. Universidad Nacional de Córdoba. Instituto de Investigaciones en Ciencias de la Salud; ArgentinaFil: Moreira Espinoza, María José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Ciencias de la Salud. Universidad Nacional de Córdoba. Instituto de Investigaciones en Ciencias de la Salud; ArgentinaFil: Cantarelli, Verónica Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Ciencias de la Salud. Universidad Nacional de Córdoba. Instituto de Investigaciones en Ciencias de la Salud; ArgentinaFil: Ponzio, Marina Flavia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Ciencias de la Salud. Universidad Nacional de Córdoba. Instituto de Investigaciones en Ciencias de la Salud; ArgentinaFil: Arja, Ana. Universidad Nacional de Córdoba. Facultad de Medicina. Departamento de Fisiología Humana y Física Biomédica. Cátedra de Fisiología Humana; ArgentinaFil: Rabaglino, Maria Belen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Ciencias de la Salud. Universidad Nacional de Córdoba. Instituto de Investigaciones en Ciencias de la Salud; ArgentinaFil: Martini, Ana Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Ciencias de la Salud. Universidad Nacional de Córdoba. Instituto de Investigaciones en Ciencias de la Salud; Argentin

    Proxima Centauri b is not a transiting exoplanet

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    We report Spitzer Space Telescope observations during predicted transits of the exoplanet Proxima Centauri b. As the nearest terrestrial habitable-zone planet we will ever discover, any potential transit of Proxima b would place strong constraints on its radius, bulk density, and atmosphere. Subsequent transmission spectroscopy and secondary-eclipse measurements could then probe the atmospheric chemistry, physical processes, and orbit, including a search for biosignatures. However, our photometric results rule out planetary transits at the 200~ppm level at 4.5 μm~{\mu}m, yielding a 3σ\sigma upper radius limit of 0.4~R_\rm{\oplus} (Earth radii). Previous claims of possible transits from optical ground- and space-based photometry were likely correlated noise in the data from Proxima Centauri's frequent flaring. Follow-up observations should focus on planetary radio emission, phase curves, and direct imaging. Our study indicates dramatically reduced stellar activity at near-to-mid infrared wavelengths, compared to the optical. Proxima b is an ideal target for space-based infrared telescopes, if their instruments can be configured to handle Proxima's brightness.Comment: 8 pages, 3 figures, 2 tables, accepted for publication in MNRA

    Aplicación web para la planeación de horarios académicos en la PUJ - JPlanner

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    Este trabajo es la solución que el equipo propone para un problema que la DTI (Dirección de tecnologías de la información) propuso en una reunión en el año 2018. JPlanner es un sistema que cambiará el método de registro de clase en la Pontificia Universidad Javeriana. Actualmente, el sistema PeopleSoft presenta muchos problemas sobre los cuales se profundizará más adelante, JPlanner busca ser el sistema de estudiantes para estudiantes que solucione la mayoría de estos problemas brin-dando la mejor solución para la universidad. Se realizaron pruebas para medir la aceptación del sistema final, los resultados de estos estudios nos muestran la aceptación de nuestro sistema por parte de los estudiantes y nos ayudan brindando oportunidades de trabajo futuro para mejorar la aplicación.This work is the solution that the team proposes for a problem that the DTI (Directorate of information technologies) proposed at a meeting in 2018. JPlanner is a system that will change the method of class registration at the Pontificia Universidad Javeriana. Currently, the PeopleSoft system presents many problems that will be deepened later, JPlanner seeks to be the student system for students that solves most of these problems by providing the best solution for the university. Tests were carried out to measure the acceptance of the final system, the results of these studies show us the acceptance of our system by the students and they help us by providing opportunities for future work to improve the application.Ingeniero (a) de SistemasPregrad

    Fungal biodiversity profiles 21–30

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    The authors describe ten new taxa for science using mostly both morphological and molecular data. In Basidiomycota, descriptions are provided for Botryobasidium fusisporum sp. nov., B. triangulosporum sp. nov., Cantharellus hydnoides sp. nov. and Hydnum aerostatisporum sp. nov. in Cantharellales; Lactarius rahjamalensis sp. nov. and Russula pseudoaurantiophylla sp. nov. in Russulales and for Mycena paraguayensis comb. nov. in Agaricales. In Ascomycota and hyphomycetes, descriptions are provided for Colletotrichurn eryngiicola sp. nov. (Glomerellales), Corynesporella indica sp. nov. (incertae sedis) and Repetophragma zygopetali sp. nov. (Microthyriales)

    Estimating the global conservation status of more than 15,000 Amazonian tree species

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    Estimates of extinction risk for Amazonian plant and animal species are rare and not often incorporated into land-use policy and conservation planning. We overlay spatial distribution models with historical and projected deforestation to show that at least 36% and up to 57% of all Amazonian tree species are likely to qualify as globally threatened under International Union for Conservation of Nature (IUCN) Red List criteria. If confirmed, these results would increase the number of threatened plant species on Earth by 22%. We show that the trends observed in Amazonia apply to trees throughout the tropics, and we predict thatmost of the world’s >40,000 tropical tree species now qualify as globally threatened. A gap analysis suggests that existing Amazonian protected areas and indigenous territories will protect viable populations of most threatened species if these areas suffer no further degradation, highlighting the key roles that protected areas, indigenous peoples, and improved governance can play in preventing large-scale extinctions in the tropics in this century

    Estimating the global conservation status of more than 15,000 Amazonian tree species

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    Geography and ecology shape the phylogenetic composition of Amazonian tree communities

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    AimAmazonia hosts more tree species from numerous evolutionary lineages, both young and ancient, than any other biogeographic region. Previous studies have shown that tree lineages colonized multiple edaphic environments and dispersed widely across Amazonia, leading to a hypothesis, which we test, that lineages should not be strongly associated with either geographic regions or edaphic forest types.LocationAmazonia.TaxonAngiosperms (Magnoliids; Monocots; Eudicots).MethodsData for the abundance of 5082 tree species in 1989 plots were combined with a mega-phylogeny. We applied evolutionary ordination to assess how phylogenetic composition varies across Amazonia. We used variation partitioning and Moran's eigenvector maps (MEM) to test and quantify the separate and joint contributions of spatial and environmental variables to explain the phylogenetic composition of plots. We tested the indicator value of lineages for geographic regions and edaphic forest types and mapped associations onto the phylogeny.ResultsIn the terra firme and várzea forest types, the phylogenetic composition varies by geographic region, but the igapó and white-sand forest types retain a unique evolutionary signature regardless of region. Overall, we find that soil chemistry, climate and topography explain 24% of the variation in phylogenetic composition, with 79% of that variation being spatially structured (R2 = 19% overall for combined spatial/environmental effects). The phylogenetic composition also shows substantial spatial patterns not related to the environmental variables we quantified (R2 = 28%). A greater number of lineages were significant indicators of geographic regions than forest types.Main ConclusionNumerous tree lineages, including some ancient ones (&gt;66 Ma), show strong associations with geographic regions and edaphic forest types of Amazonia. This shows that specialization in specific edaphic environments has played a long-standing role in the evolutionary assembly of Amazonian forests. Furthermore, many lineages, even those that have dispersed across Amazonia, dominate within a specific region, likely because of phylogenetically conserved niches for environmental conditions that are prevalent within regions

    Geography and ecology shape the phylogenetic composition of Amazonian tree communities

    Get PDF
    Aim: Amazonia hosts more tree species from numerous evolutionary lineages, both young and ancient, than any other biogeographic region. Previous studies have shown that tree lineages colonized multiple edaphic environments and dispersed widely across Amazonia, leading to a hypothesis, which we test, that lineages should not be strongly associated with either geographic regions or edaphic forest types. Location: Amazonia. Taxon: Angiosperms (Magnoliids; Monocots; Eudicots). Methods: Data for the abundance of 5082 tree species in 1989 plots were combined with a mega-phylogeny. We applied evolutionary ordination to assess how phylogenetic composition varies across Amazonia. We used variation partitioning and Moran\u27s eigenvector maps (MEM) to test and quantify the separate and joint contributions of spatial and environmental variables to explain the phylogenetic composition of plots. We tested the indicator value of lineages for geographic regions and edaphic forest types and mapped associations onto the phylogeny. Results: In the terra firme and várzea forest types, the phylogenetic composition varies by geographic region, but the igapó and white-sand forest types retain a unique evolutionary signature regardless of region. Overall, we find that soil chemistry, climate and topography explain 24% of the variation in phylogenetic composition, with 79% of that variation being spatially structured (R2^{2} = 19% overall for combined spatial/environmental effects). The phylogenetic composition also shows substantial spatial patterns not related to the environmental variables we quantified (R2^{2} = 28%). A greater number of lineages were significant indicators of geographic regions than forest types. Main Conclusion: Numerous tree lineages, including some ancient ones (>66 Ma), show strong associations with geographic regions and edaphic forest types of Amazonia. This shows that specialization in specific edaphic environments has played a long-standing role in the evolutionary assembly of Amazonian forests. Furthermore, many lineages, even those that have dispersed across Amazonia, dominate within a specific region, likely because of phylogenetically conserved niches for environmental conditions that are prevalent within regions

    Geographic patterns of tree dispersal modes in Amazonia and their ecological correlates

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    Aim: To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser-availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource-availability hypothesis). Time period: Tree-inventory plots established between 1934 and 2019. Major taxa studied: Trees with a diameter at breast height (DBH) ≥ 9.55 cm. Location: Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield. Methods: We assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance-weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes. Results: Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra-firme forests (excluding podzols) compared to flooded forests. Main conclusions: The disperser-availability hypothesis was well supported for abiotic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the proportional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling recruitment across forest types
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