294 research outputs found

    Virulence factors among enterococci isolated from traditional fermented meat products produced in the North of Portugal

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    The aim of this work was to characterize Enterococcus spp. isolated from Alheira, Chouriça de Vinhais and Salpicão de Vinhais, fermented meat products produced in the North of Portugal, concerning their potential pathogenicity. One hundred and eighty two isolates (76 identified as Enterococcus faecalis, 44 as Enterococcus faecium, 1 as Enterococcus casseliflavus and 61 as Enterococcus spp.) were studied. Twenty six percent of isolates were gelatinase producers. None of the isolates produced lipase nor DNase activities. Hemolytic activity using sheep and human blood from two types (A and O) was assessed. One isolate was b-hemolytic in human blood. Results obtained in sheep blood were quite different from those obtained in human blood. Biofilm production in batch and in fed-batch mode was evaluated. In batch mode, only 28.0% and 3.9% of isolates were classified as moderate and strong biofilm producers, respectively, and in fed-batch mode, 35.7% and 63.2% of isolates were classified as moderate and strong biofilm producers, respectively. The presence of 13 virulence genes (efaAfs, efaAfm, esp, agg, cylM, cylB, cylA, cylLL cylLs and gelE) were investigated by PCR. The majority of enterococcal isolates showed the presence of one or more virulence factors, the most frequent genotype being efaAfs+ gelE+ agg+ (41.5%). E. faecalis isolates harbored multiple virulence traits, while E. faecium isolates were generally free of virulence determinants. Phenotypic and genotypic evidence of potential virulence factors were identified in Enterococcus spp. isolates, which is a reason of concern

    Cassini UVIS Observations of the Io Plasma Torus. IV. Modeling Temporal and Azimuthal Variability

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    In this fourth paper in a series, we present a model of the remarkable temporal and azimuthal variability of the Io plasma torus observed during the Cassini encounter with Jupiter. Over a period of three months, the Cassini Ultraviolet Imaging Spectrograph (UVIS) observed a dramatic variation in the average torus composition. Superimposed on this long-term variation, is a 10.07-hour periodicity caused by an azimuthal variation in plasma composition subcorotating relative to System III longitude. Quite surprisingly, the amplitude of the azimuthal variation appears to be modulated at the beat frequency between the System III period and the observed 10.07-hour period. Previously, we have successfully modeled the months-long compositional change by supposing a factor of three increase in the amount of material supplied to Io's extended neutral clouds. Here, we extend our torus chemistry model to include an azimuthal dimension. We postulate the existence of two azimuthal variations in the number of super-thermal electrons in the torus: a primary variation that subcorotates with a period of 10.07 hours and a secondary variation that remains fixed in System III longitude. Using these two hot electron variations, our model can reproduce the observed temporal and azimuthal variations observed by Cassini UVIS.Comment: Revised 24 August 2007 Accepted by Icarus, 50 pages, 2 Tables, 8 figure

    Which mechanism underlies the water-like anomalies in core-softened potentials?

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    Using molecular dynamics simulations we investigate the thermodynamic of particles interacting with a continuous and a discrete versions of a core-softened (CS) intermolecular potential composed by a repulsive shoulder. Dynamic and structural properties are also analyzed by the simulations. We show that in the continuous version of the CS potential the density at constant pressure has a maximum for a certain temperature. Similarly the diffusion constant, DD, at a constant temperature has a maximum at a density ρmax\rho_{\mathrm{max}} and a minimum at a density ρmin<ρmax\rho_{\mathrm{min}}<\rho_{\mathrm{max}}, and structural properties are also anomalous. For the discrete CS potential none of these anomalies are observed. The absence of anomalies in the discrete case and its presence in the continuous CS potential are discussed in the framework of the excess entropy.Comment: 8 page

    Search for the Rare Decay KL --> pi0 ee

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    The KTeV/E799 experiment at Fermilab has searched for the rare kaon decay KL--> pi0ee. This mode is expected to have a significant CP violating component. The measurement of its branching ratio could support the Standard Model or could indicate the existence of new physics. This letter reports new results from the 1999-2000 data set. One event is observed with an expected background at 0.99 +/- 0.35 events. We set a limit on the branching ratio of 3.5 x 10^(-10) at the 90% confidence level. Combining the results with the dataset taken in 1997 yields the final KTeV result: BR(KL --> pi0 ee) < 2.8 x 10^(-10) at 90% CL.Comment: 4 pages, three figure

    Central Santa Catarina coastal dunefields chronology and their relation to relative sea level and climatic changes

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    During the past decades, there have been contrarian explanations for the formation and stabilization of coastal dunefields: while many authors believe the dunes formation would be enhanced by falling sea level, others argue that a rising or stable sea level context would be favorable. For Brazilian coastal dunefields, the second hypothesis seems to be more consistent with the luminescence ages found so far; however, most of these data were obtained without using the SAR protocol. Another point of concern is the role of climate change in the aeolian system, which is still not very clear. The aim of this paper is to try to clarify these two questions. To this end, five coastal dunefields were selected in central Santa Catarina coast. The remote sensing and dating results allowed the discrimination and mapping of at least four aeolian generations. Their age distribution in relation to the global curve of relative sea level variation during the Late Pleistocene allows us to suggest that the formation of Aeolian dunefields in the coastal context is supported by stable relative sea level. However, relative sea level is not the only determinant for the formation and preservation of the aeolian coastal dunes. Evidences of climatic control indicate that the initiation of dunefields would be favored by periods of less humidity while their stabilization would occur preferably during the periods of rain intensification, connected to monsoon activity

    Evaluation of the possibility of using diatomite natural mineral as a composite agent in acrylic coating

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    WOS: 000427736200014In the present study the possibility of the commercially available acryl and diatomite earth (DE) mineral as a composite coating for corrosion protection of Mg alloys has been evaluated. The acrylic coating is used as a top coating in a wide field of applications like automotive, aerospace, medicine and electronics where it shows beneficial properties. Diatomite-dispersed acrylic paint was applied over the substrate by conventional spray technique with an air pressure of 3 kg cm(-2). Firstly the acryl was mixed with hardener and then the DE was added to the mixture. Four types of coating with 0, 2, 4, 8 g/L DE have been prepared. The results show that adding up to 4 g/L of the DE improved the corrosion resistance and produced a coating with acceptable surface roughness

    Peppers of the genus Capiscum cultivated in Roraima, Brazilian Amazonia: Habits and forms of use

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    The objective of this study was relate and discuss both the habit and the most common forms of using Capsicum peppers cultivated in the state of Roraima and utilized by indigenous people and colonist communities from the other regions of the country.O objetivo do trabalho foi o de relacionar e discutir os hábitos e as formas de uso mais comuns das pimentas do gênero Capsicum cultivadas em Roraima, e utilizadas pelos povos indígenas e comunidades migrantes de outras regiões do país
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