882 research outputs found

    Seasonal Botanical Composition and Available Forage of Natural Grasslands in the Southeastern Range Region of Rio Grande Do Sul, Brazil

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    The objective of the study was to verify the influence of climatic seasons on botanical composition and on available dry matter of grasslands in the physiographic region known as Serra do Sudeste (Southeastern Range), RS, Brazil. The climate is Cfb according to Koëppen`s classification. The experiment was conducted in two natural grasslands submitted to two pre-experimental stocking rates [area 1: 0.65 AU ha-1 (normal grazing); area 2: over 2.0 AU ha-1 (overgrazing); AU: Animal Unit = 500kg live weight]. Stocking rates throughout the experimental period (June 1996–July 1997) were 0.4 and 0.65 AU ha-1, over winter and the other seasons, respectively. The evaluations were made at the end of each season, using the Botanal package. There was a short forage supply over late autumn/early winter. The two species groupings warm-season grasses (70–78% of total dry matter) and broad leaves (18– 24%) were the main components of the vegetation in the lower layer of the two grasslands. Warm-season grasses had their participation slightly increased during the warmer seasons. The pre-experimental overgrazing of area 2 favoured the contribution of the minor groups cool-season grasses, warm-season legumes and cool-season legumes

    Comparing the Bacterial Diversity of Acute and Chronic Dental Root Canal Infections

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    This study performed barcoded multiplex pyrosequencing with a 454 FLX instrument to compare the microbiota of dental root canal infections associated with acute (symptomatic) or chronic (asymptomatic) apical periodontitis. Analysis of samples from 9 acute abscesses and 8 chronic infections yielded partial 16S rRNA gene sequences that were taxonomically classified into 916 bacterial species-level operational taxonomic units (OTUs) (at 3% divergence) belonging to 67 genera and 13 phyla. The most abundant phyla in acute infections were Firmicutes (52%), Fusobacteria (17%) and Bacteroidetes (13%), while in chronic infections the dominant were Firmicutes (59%), Bacteroidetes (14%) and Actinobacteria (10%). Members of Fusobacteria were much more prevalent in acute (89%) than in chronic cases (50%). The most abundant/prevalent genera in acute infections were Fusobacterium and Parvimonas. Twenty genera were exclusively detected in acute infections and 18 in chronic infections. Only 18% (n = 165) of the OTUs at 3% divergence were shared by acute and chronic infections. Diversity and richness estimators revealed that acute infections were significantly more diverse than chronic infections. Although a high interindividual variation in bacterial communities was observed, many samples tended to group together according to the type of infection (acute or chronic). This study is one of the most comprehensive in-deep comparisons of the microbiota associated with acute and chronic dental root canal infections and highlights the role of diverse polymicrobial communities as the unit of pathogenicity in acute infections. The overall diversity of endodontic infections as revealed by the pyrosequencing technique was much higher than previously reported for endodontic infections

    PCR-based detection of Babesia bovis and Babesia bigemina in their natural host Boophilus microplus and cattle.

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    PCR and nested-PCR methods were used to assess the frequency of Babesia bovis and Babesia bigemina infection in Boophilus microplus engorged females and eggs and in cattle reared in an area with endemic babesiosis. Blood and the engorged female ticks were from 27 naturally infested calves and 25 crossbred cows. The frequency of both Babesia species was similar in calves and cows (P>0.05). Babesia bovis was detected in 23 (85.2%) calves and in 25 (100%) cows and B. bigemina was detected in 25 (92.6%) calves and in 21 (84%) cows. Mixed infections with the both Babesia species were identified in 42 animals, 21 in each age category. Of female ticks engorged on calves, 34.9% were negative and single species infection with B. bigemina (56.2%) was significantly more frequent (P0.05) to the frequency of single B. bigemina infection (15.9%). Mixed Babesia infection was lower (P<O.OI) than single species infection in female ticks engorged either in cows (5.7%) or in calves (4.3%). An egg sample from each female was analysed for the presence of Babesia species. Of the egg samples from female ticks infected with B. bovis, 26 (47.3%) were infected while from those from female ticks infected with B. bigemina 141 (76.6%) were infected (P<0.01). The results showed that although the frequency of both species of Babesia was similar in calves and cows, the infectivity of B. bigemina was higher to ticks fed on calves while to those ticks fed on cows the infectivity of both Babesia species was similar

    Improvement in the Adsorption of Anionic and Cationic Dyes From Aqueous Solutions: A Comparative Study Using Aluminium Pillared Clays and Activated Carbon

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    The aim of this work was to evaluate the adsorption properties of anionic dye Reactive Black 5 (RB5) and cationic dye Methylene Blue (MB) from salted aqueous solution using natural clay, aluminum pillared clay (Al-PILC), and activated carbon. The textural properties of the materials were obtained by N2 adsorption at 77 K and the structural properties of natural and pillared clays were determined by X-ray diffraction. The effect of pH, contact time, initial concentration of dye, and influence of the addition of NaCl were evaluated by batch adsorption. Adsorption isotherms of Al-PILC, in different salt concentration were compared with natural clay and activated carbon. The adsorption isotherms were well fitted by the Langmuir and Langmuir-Freundlich models. The process of pillaring only improved the adsorption of the anionic dye RB5. Depending on the system adsorbent/adsorbate analyzed, the salt concentration can either help or hinder dye adsorption. We found that a special morphology formed during the process of pillaring greatly increased adsorption of the MB cationic dye in the range of high salt concentrations. This unexpected result may help in developing new pillarization strategies to treat effluents with high salt content.Fil: Aguiar, J. E.. Universidade Federal do Ceará. Centro de Tecnologia. Departamento de Engenharia Química. Grupo de Pesquisa em Separações por Adsorção; BrasilFil: Bezerra, B. T. C.. Universidade Federal do Ceará. Centro de Tecnologia. Departamento de Engenharia Química. Grupo de Pesquisa em Separações por Adsorção; BrasilFil: Siqueira, A. C. A.. Universidade Federal do Ceará. Centro de Tecnologia. Departamento de Engenharia Química. Grupo de Pesquisa em Separações por Adsorção; BrasilFil: Barrera Diaz, Deicy Amparo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Física Aplicada; ArgentinaFil: Sapag, Manuel Karim. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Física Aplicada; ArgentinaFil: Azevedo, D. C. S.. Universidade Federal do Ceará. Centro de Tecnologia. Departamento de Engenharia Química. Grupo de Pesquisa em Separações por Adsorção; BrasilFil: Lucena, S. M. P.. Universidade Federal do Ceará. Centro de Tecnologia. Departamento de Engenharia Química. Grupo de Pesquisa em Separações por Adsorção; BrasilFil: Silva Jr., I. J.. Universidade Federal do Ceará. Centro de Tecnologia. Departamento de Engenharia Química. Grupo de Pesquisa em Separações por Adsorção; Brasi

    Distinctive features of the microbiota associated with different forms of apical periodontitis

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    Microorganisms infecting the dental root canal system play an unequivocal role as causative agents of apical periodontitis. Although fungi, archaea, and viruses have been found in association with some forms of apical periodontitis, bacteria are the main microbial etiologic agents of this disease. Bacteria colonizing the root canal are usually organized in communities similar to biofilm structures. Culture and molecular biology technologies have demonstrated that the endodontic bacterial communities vary in species richness and abundance depending on the different types of infection and different forms of apical periodontitis. This review paper highlights the distinctive features of the endodontic microbiota associated with diverse clinical conditions

    Sensitivity and Specificity of Multiple Kato-Katz Thick Smears and a Circulating Cathodic Antigen Test for Schistosoma mansoni Diagnosis Pre- and Post-repeated-Praziquantel Treatment

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    Two Kato-Katz thick smears (Kato-Katzs) from a single stool are currently recommended for diagnosing Schistosoma mansoni infections to map areas for intervention. This ‘gold standard’ has low sensitivity at low infection intensities. The urine point-of-care circulating cathodic antigen test (POC-CCA) is potentially more sensitive but how accurately they detect S. mansoni after repeated praziquantel treatments, their suitability for measuring drug efficacy and their correlation with egg counts remain to be fully understood. We compared the accuracies of one to six Kato-Katzs and one POC-CCA for the diagnosis of S. mansoni in primary-school children who have received zero to ten praziquantel treatments. We determined the impact each diagnostic approach may have on monitoring and evaluation (M&E) and drug-efficacy findings

    Mapping units based on spatial uncertainty of magnetic susceptibility and clay content.

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    Made available in DSpace on 2018-10-04T00:47:10Z (GMT). No. of bitstreams: 1 EderMappingunits.pdf: 1075932 bytes, checksum: ee50596ec3d04d80ac2fa8eb3af17b33 (MD5) Previous issue date: 2018-10-03bitstream/item/183817/1/Eder-Mapping-units.pd

    Anthropogenic disturbance in tropical forests can double biodiversity loss from deforestation

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    Concerted political attention has focused on reducing deforestation1,2,3, and this remains the cornerstone of most biodiversity conservation strategies4,5,6. However, maintaining forest cover may not reduce anthropogenic forest disturbances, which are rarely considered in conservation programmes6. These disturbances occur both within forests, including selective logging and wildfires7,8, and at the landscape level, through edge, area and isolation effects9. Until now, the combined effect of anthropogenic disturbance on the conservation value of remnant primary forests has remained unknown, making it impossible to assess the relative importance of forest disturbance and forest loss. Here we address these knowledge gaps using a large data set of plants, birds and dung beetles (1,538, 460 and 156 species, respectively) sampled in 36 catchments in the Brazilian state of Pará. Catchments retaining more than 69–80% forest cover lost more conservation value from disturbance than from forest loss. For example, a 20% loss of primary forest, the maximum level of deforestation allowed on Amazonian properties under Brazil’s Forest Code5, resulted in a 39–54% loss of conservation value: 96–171% more than expected without considering disturbance effects. We extrapolated the disturbance-mediated loss of conservation value throughout Pará, which covers 25% of the Brazilian Amazon. Although disturbed forests retained considerable conservation value compared with deforested areas, the toll of disturbance outside Pará’s strictly protected areas is equivalent to the loss of 92,000–139,000 km2 of primary forest. Even this lowest estimate is greater than the area deforested across the entire Brazilian Amazon between 2006 and 2015 (ref. 10). Species distribution models showed that both landscape and within-forest disturbances contributed to biodiversity loss, with the greatest negative effects on species of high conservation and functional value. These results demonstrate an urgent need for policy interventions that go beyond the maintenance of forest cover to safeguard the hyper-diversity of tropical forest ecosystems
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