7,681 research outputs found

    Herbage Production of Tanzania Grass (\u3cem\u3ePanicum maximum\u3c/em\u3e cv. Tanzania) Submitted to Combinations of Frequencies and Intensities of Grazing by Cattle

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    Animal production from pastures is a complex process comprising three main stages: herbage growth, consumption by grazing animals and conversion into animal products (Hodgson, 1990). Utilisation is the stage where the grazier finds greater flexibility for management, probably because most processes related to harvest of the produced herbage by the grazing animals are very responsive to manipulation and control of defoliation practices. The objective of this study was to evaluate herbage production of a Panicum maximum cv. Tanzania pasture submitted to combinations of frequencies and intensities of grazing

    Leaf Appearance and Elongation in Panicum maximum cv. Tanzania Tillers of Varying Ages

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    A sward may be considered as a tiller population of varying ages and sizes, and these different age groups are likely to present distinct behaviour in terms of growth and herbage production. However, there is very little information on how tiller age, in association with grazing management practices (e.g. frequency and intensity of grazing), alter morphogenetic characteristics and, therefore, herbage production. Against this background, the present experiment had the objective to evaluate leaf appearance and elongation in Panicum maximum cv. Tanzania tillers of different age groups when submitted to intermittent grazing regimes

    Nonextensive Thermostatistics and the H-Theorem

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    The kinetic foundations of Tsallis' nonextensive thermostatistics are investigated through Boltzmann's transport equation approach. Our analysis follows from a nonextensive generalization of the ``molecular chaos hypothesis". For q>0q>0, the qq-transport equation satisfies an HH-theorem based on Tsallis entropy. It is also proved that the collisional equilibrium is given by Tsallis' qq-nonextensive velocity distribution.Comment: 4 pages, no figures, corrected some typo

    Survey of Zoonotic Diarrheagenic Protist and Hepatitis E Virus in Wild Boar (Sus scrofa) of Portugal

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    Simple Summary Enteropathogenic viruses, such as hepatitis E virus, and diarrhoeagenic protists have been frequently reported in swine and can infect a wide range of mammals, including humans. Data on their fecal shedding and circulation pathways are still lacking or incomplete. Hence, the aim of the present study was to characterize the presence of microeukaryotes and HEV in the wild boar of Portugal. Of the 144 samples tested, 2 showed the presence of Cryptosporidium scrofarum, 21 Balantioides coli, 42 Blastocystis ST5, and 4 HEV genotype 3. The present work shows that potentially zoonotic protozoa and HEV are circulating in wild boar populations in Portugal. Enteropathogenic parasites and viruses have been frequently reported in swine and can infect a wide range of mammals, including humans. Among the wide variety of parasites infecting swine, diarrhoeagenic protists are among those that cause significant morbidity. Hepatitis E virus (HEV) has also been reported both in domestic pigs and wild boar and is known to have an important public health significance. These agents share the fecal-oral transmission route, but data on their fecal shedding and circulation pathways are still lacking or incomplete. Hence, the aim of the present study was to characterize the presence of microeukaryotes and HEV in the wild boar of Portugal. Wild boar stool samples (n = 144) were obtained during the official hunting seasons (October to February) in 2018/2019, 2019/2020, and 2021/2022 and tested for Cryptosporidium spp., Balantioides coli, Giardia duodenalis, Blastocystis sp., Enterocytozoon bieneusi and HEV by molecular assays, followed by sequencing and phylogenetic analysis. We have detected Cryptosporidium scrofarum (1.4%, 95% CI: 0.2-4.9), B. coli (14.6%, 95% CI: 9.2-21.4), Blastocystis ST5 (29.2%, 95% CI: 21.9-37.2) and HEV genotype 3 (2.8%, 95% CI: 0.7-6.9; subgenotypes 3e and 3m). Co-infections were observed in thirteen animals where two were positive for both HEV and B. coli, one was positive for both C. scrofarum and Blastocystis ST5, and ten were positive for both B. coli and Blastocystis ST5. Giardia duodenalis and E. bieneusi were not detected in the surveyed wild boar population. As far as we know, this is the first report describing protist infections by Cryptosporidium spp., B. coli, and Blastocystis sp., as well as the first identification of the emerging HEV genotype 3m in wild boar of Portugal. The present work shows that potentially zoonotic protozoa and HEV are circulating in wild boar populations in Portugal. Awareness and epidemic-surveillance network implementation measures targeting wild boar are needed to prevent the spread of these pathogenic agents to humans.This research was funded by Fundacao para Ciencia e Tecnologia (FCT), grant number 2021.09461.BD

    Accurate masses and radii of normal stars: modern results and applications

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    This paper presents and discusses a critical compilation of accurate, fundamental determinations of stellar masses and radii. We have identified 95 detached binary systems containing 190 stars (94 eclipsing systems, and alpha Centauri) that satisfy our criterion that the mass and radius of both stars be known to 3% or better. To these we add interstellar reddening, effective temperature, metal abundance, rotational velocity and apsidal motion determinations when available, and we compute a number of other physical parameters, notably luminosity and distance. We discuss the use of this information for testing models of stellar evolution. The amount and quality of the data also allow us to analyse the tidal evolution of the systems in considerable depth, testing prescriptions of rotational synchronisation and orbital circularisation in greater detail than possible before. The new data also enable us to derive empirical calibrations of M and R for single (post-) main-sequence stars above 0.6 M(Sun). Simple, polynomial functions of T(eff), log g and [Fe/H] yield M and R with errors of 6% and 3%, respectively. Excellent agreement is found with independent determinations for host stars of transiting extrasolar planets, and good agreement with determinations of M and R from stellar models as constrained by trigonometric parallaxes and spectroscopic values of T(eff) and [Fe/H]. Finally, we list a set of 23 interferometric binaries with masses known to better than 3%, but without fundamental radius determinations (except alpha Aur). We discuss the prospects for improving these and other stellar parameters in the near future.Comment: 56 pages including figures and tables. To appear in The Astronomy and Astrophysics Review. Ascii versions of the tables will appear in the online version of the articl

    Production of Galacto-oligosaccharides during lactose hydrolysis by Aspergillus oryzae β-galactosidase immobilized on polysiloxane-polyvinyl alcohol magnetic support

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    CHISA 2008 - 18th International Congress of Chemical and Process Engineering (CD-ROM of Full Texts)Galactooligosaccharides (GOSs) are nondigestible food ingredients that encourage proliferation of selected groups of the colonic microflora, thereby altering the composition toward a more beneficial community. The GOSs can be formed enzymatically and are produced from lactose by the action of β -galactosidases which have transgalactosylation activity. β-Galactosidase is an enzyme with wide industrial applications, mostly in the dairy industry for the hydrolysis of lactose and, more recently, in the synthesis of galactooligosaccharides. The GOS produced during lactose hydrolysis by A. oryzae-galactosidase immobilized on Polysiloxane-Polyvinyl Alcohol Magnetic (mPOS-PVA) was studied. The initial lactose concentration in the reaction media affected the total amounts and types of GOS roduced. In general, higher initial lactose concentrations produced more and larger GOS. A maximum GOS production of 25-26% (w/w) of total sugars was achieved at near 50% lactose conversion from 400 g/L of lactose at pH 4.5 and 40 ºC. The major types of GOS formed were tri-saccharides, accounting for more than 70% of the total GOS produced in the reactions. Any changes in GOS formation were observed in different temperature and pH, but the reaction rate was affected. The concentrations encountered near maximum GOS greatly inhibited the reactions and reduced GOS yield in the presence of galactose and glucose. The mPOS-PVA as the support matrix for enzyme immobilization did not affect the GOS formation characteristics of the enzyme, s uggesting no diffusion limitation in the enzyme carrier. Furthermore, the mPOS-PVA β -galactosidase preparation retained about 70% of the initial activity after being reutilized 15-times. Data obtained were fitted to kinetic model based on the Michaelis-Menten mechanism by non linear regression to determine the influence of the temperature and the lactose concentration on the activity of the enzyme. Hence, one can conclude that mPOS-PVA is an attractive and efficient support for β-galactosidase immobilization, due to the simplicity of the matrix preparation and immobilization methodology, the catalytic properties of the derivative thus produced and the straightforward removal of the enzymatic derivative from the reaction medium by simply applying a magnetic field around the bioreactorinfo:eu-repo/semantics/publishedVersio

    Results of the engineering run of the coherent neutrino nucleus interaction experiment (CONNIE)

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    The CONNIE detector prototype is operating at a distance of 30 m from the core of a 3.8 GWth nuclear reactor with the goal of establishing Charge-Coupled Devices (CCD) as a new technology for the detection of coherent elastic neutrino-nucleus scattering. We report on the results of the engineering run with an active mass of 4 g of silicon. The CCD array is described, and the performance observed during the first year is discussed. A compact passive shield was deployed around the detector, producing an order of magnitude reduction in the background rate. The remaining background observed during the run was stable, and dominated by internal contamination in the detector packaging materials. The in-situ calibration of the detector using X-ray lines from fluorescence demonstrates good stability of the readout system. The event rates with the reactor ON and OFF are compared, and no excess is observed coming from nuclear fission at the power plant. The upper limit for the neutrino event rate is set two orders of magnitude above the expectations for the standard model. The results demonstrate the cryogenic CCD-based detector can be remotely operated at the reactor site with stable noise below2 e RMS and stable background rates. The success of the engineering test provides a clear path for the upgraded 100 g detector to be deployed during 2016.Fil: Aguilar Arevalo, A.. Universidad Nacional Autónoma de México; MéxicoFil: Bertou, Xavier Pierre Louis. Comisión Nacional de Energía Atómica; Argentina. Comisión Nacional de Energía Atómica. Fundación José A. Balseiro; ArgentinaFil: Bonifazi, C.. Universidade Federal do Rio de Janeiro; BrasilFil: Butner, M.. Fermi National Accelerator Laboratory; Estados UnidosFil: Cancelo, G.. Fermi National Accelerator Laboratory; Estados UnidosFil: Castañeda Vazquez, A.. Universidad Nacional Autónoma de México; MéxicoFil: Cervantes Vergara, B.. Universidad Nacional Autónoma de México; MéxicoFil: Chavez, C. R.. Universidad Nacional de Asunción; ParaguayFil: Da Motta, H.. Centro Brasileiro de Pesquisas Físicas; BrasilFil: D'Olivo, J. C.. Universidad Nacional Autónoma de México; MéxicoFil: Dos Anjos, J.. Centro Brasileiro de Pesquisas Físicas; BrasilFil: Estrada, J.. Fermi National Accelerator Laboratory; Estados UnidosFil: Fernández Moroni, Guillermo. Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto ; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ford, R.. Fermi National Accelerator Laboratory; Estados UnidosFil: Foguel, A.. Centro Brasileiro de Pesquisas Físicas; Brasil. Universidade Federal do Rio de Janeiro; BrasilFil: Hernandez Torres, K. P.. Universidad Nacional Autónoma de México; MéxicoFil: Izraelevitch, F.. Fermi National Accelerator Laboratory; Estados UnidosFil: Kavner, A.. University of Michigan; Estados UnidosFil: Kilminster, B.. Universitat Zurich; SuizaFil: Kuk, K.. Fermi National Accelerator Laboratory; Estados UnidosFil: Lima Jr, H. P.. Centro Brasileiro de Pesquisas Físicas; BrasilFil: Makler, M.. Centro Brasileiro de Pesquisas Físicas; BrasilFil: Molina, J.. Universidad Nacional de Asunción; ParaguayFil: Moreno Granados, G.. Universidad Nacional Autónoma de México; MéxicoFil: Moro, Juan Manuel. Universidad Nacional del Sur. Departamento de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Paolini, Eduardo Emilio. Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto ; ArgentinaFil: Sofo Haro, Miguel Francisco. Comision Nacional de Energia Atomica. Gerencia D/area de Energia Nuclear; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Tiffenberg, Javier Sebastian. Fermi National Accelerator Laboratory; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Trillaud, F.. Universidad Nacional Autónoma de México; MéxicoFil: Wagner, S.. Centro Brasileiro de Pesquisas Físicas; Brasil. Pontificia Universidade Católica do Rio Grande do Sul; Brasi

    Deep sequencing evidence from single grapevine plants reveals a virome dominated by mycoviruses

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    We have characterized the virome in single grapevines by 454 high-throughput sequencing of double-stranded RNA recovered from the vine stem. The analysis revealed a substantial set of sequences similar to those of fungal viruses. Twenty-six putative fungal virus groups were identified from a single plant source. These represented half of all known mycoviral families including the Chrysoviridae, Hypoviridae, Narnaviridae, Partitiviridae, and Totiviridae. Three of the mycoviruses were associated with Botrytis cinerea, a common fungal pathogen of grapes. Most of the rest appeared to be undescribed. The presence of viral sequences identified by BLAST analysis was confirmed by sequencing PCR products generated from the starting material using primers designed from the genomic sequences of putative mycoviruses. To further characterize these sequences as fungal viruses, fungi from the grapevine tissue were cultured and screened with the same PCR probes. Five of the mycoviruses identified in the total grapevine extract were identified again in extracts of the fungal cultures
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