1,128 research outputs found

    Dental treatment and risk of variant CJD - a case control study

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    Abstract Objective: Knowledge of risk factors for variant CJD (vCJD) remains limited, but transmission of prion proteins via re-useable medical devices, including dental instruments, or enhanced susceptibility following trauma to the oral cavity is a concern. This study aimed to identify whether previous dental treatment is a risk factor for development of vCJD. Design: Case control study Methods: Risk factor questionnaires completed by interview with relatives of 130 vCJD patients and with relatives of 66 community and 53 hospital controls were examined by a dental surgeon. Responses regarding dental treatments were analysed. Results: We did not find a statistically significant excess of risk of vCJD associated with dental treatments with the exception of extractions in an unmatched analysis of vCJD cases with community controls (p=0.02). However, this result may be explained by multiple testing. Conclusions: This is the first published study to date to examine potential links between vCJD and dental treatment. There was no convincing evidence found of an increased risk of variant CJD associated with reported dental treatment. However, the power of the study is restricted by the number of vCJD cases to date and does not preclude the possibility that some cases have resulted from secondary transmission via dental procedures. Due to the limitations of the data available, more detailed analyses of dental records are required to fully exclude the possibility of transmission via dental treatment

    Inference of breed structure in farm animals: Empirical comparison between snp and microsatellite performance

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    Knowledge of population structure is essential to improve the management and conservation of farm animal genetic resources. Microsatellites, which have long been popular for this type of analysis, are more and more neglected in favor of whole-genome single nucleotide polymorphism (SNP) chips that are now available for the main farmed animal species. In this study, we compared genetic patterns derived from microsatellites to that inferred by SNPs, considering three pairs of datasets of sheep and cattle. Population genetic differentiation analyses (Fixation index, FST ), as well as STRUCTURE analyses showed a very strong consistency between the two types of markers. Microsatellites gave pictures that were largely concordant with SNPs, although less accurate. The best concordance was found in the most complex dataset, which included 17 French sheep breeds (with a Pearson correlation coefficient of 0.95 considering the 136 values of pairwise FST, obtained with both types of markers). The use of microsatellites reduces the cost and the related analyses do not require specific computer equipment (i.e., information technology (IT) infrastructure able to provide adequate computing and storage capacity). Therefore, this tool may still be a very appropriate solution to evaluate, in a first stage, the general state of livestock at national scales. At a time when local breeds are disappearing at an alarming rate, it is urgent to improve our knowledge of them, in particular by promoting tools accessible to the greatest number

    Croissance de semi-conducteurs Ă  grand gap

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    La modĂ©lisation et la simulation des procĂ©dĂ©s de croissance tel que le transport physique en phase vapeur (PVT), le dĂ©pĂŽt chimique en phase vapeur (CVD ou HTCVD) et les techniques hybrides (CFPVT), sont suffisamment au point pour ĂȘtre utilisĂ©es comme des outils de comprĂ©hension des phĂ©nomĂšnes physiques couplĂ©s et comme des outils de conception de nouveaux procĂ©dĂ©s et d'optimisation de procĂ©dĂ©s existants. La modĂ©lisation des procĂ©dĂ©s d'Ă©laboration rassemble plusieurs voies physico-chimiques de complexitĂ© variable, depuis des Ă©tudes thermodynamiques et/ou cinĂ©tiques jusqu'aux transferts simultanĂ©s de matiĂšre et de chaleur couplĂ©es avec les bases de donnĂ©es et propriĂ©tĂ©s thermodynamiques et/ou cinĂ©tiques et de transport. DiffĂ©rentes voies de modĂ©lisation sont utilisĂ©es, thermodynamiques, cinĂ©tique ou transfert de masse, de façon couplĂ©e ou dĂ©couplĂ©e, permettant de visualiser l'Ă©volution de la croissance et ainsi comprendre le rĂŽle complexe et fortement couplĂ© des phĂ©nomĂšnes

    Mechanical land clearing to promote establishment of coastal sandplain grassland and shrubland communities

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    Author Posting. © The Author(s), 2005. This is the author's version of the work. It is posted here by permission of Blackwell Publishing for personal use, not for redistribution. The definitive version was published in Restoration Ecology 14 (2006): 220-232, doi:10.1111/j.1526-100X.2006.00124.x.The decline in grasslands and other species-rich early-successional habitats on the coastal sandplains of the northeastern U.S. has spurred management to increase the area of these declining plant communities. We mechanically removed overstory oak and applied seed from a nearby sandplain grassland on the island of Martha’s Vineyard, Massachusetts to evaluate this technique for creating an open oak community able to support sandplain herbaceous species. We compared vegetation structure and composition before and after clearing in an area of total tree removal (clearcutting), an area where 85% of tree basal area was removed (savanna cutting) and in adjacent coastal oak forest. Plant responses to clearcutting and savanna cutting were similar. Sandplain herbs colonized at high frequencies after seeding and increasing herbaceous cover from <7% before clearing to 22-38% three growing seasons later. Carex pensylvanica (Pennsylvania sedge) increased in cover ~ 6-fold, accounting for 84-90% of the increased herbaceous cover. Other native ruderals, and exotic herbs reached 6%, 2%, and 1%, cover respectively, after three years. Species richness across cleared treatments increased from 30 to 79 species. All forest species were retained. Forest shrubs and trees initially declined from their dominant cover, but rebounded after three years. Tree clearing plus seeding appeared to be a viable management practice for increasing cover of herbaceous sandplain species while causing minimal increases in exotic herbaceous cover. The long-term persistence of sandplain herbs may require periodic disturbances that limit woody regrowth.This work was funded by grants from the A. W. Mellon Foundation and the Massachusetts Environmental Trust to MBL and from the Kohlberg Foundation to TNC

    A test on Ellenberg indicator values in the Mediterranean evergreen woods (Quercetea ilicis)

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    The consistency and reliability of Ellenberg’s indicator values (Eiv) as ecological descriptors of the Mediterranean evergreen vegetation ascribed to the phytosociological class Quercetea ilicis have been checked on a set of 859 phytosociological relevĂ©s × 699 species. Diagnostic species were identified through a Twinspan analysis and their Eiv analyzed and related to the following independent variables: (1) annual mean temperatures, (2) annual rainfall. The results provided interesting insights to disentangle the current syntaxonomical framework at the alliance level demonstrating the usefulness of ecological indicator values to test the efficiency and predictivity of the phytosociological classification

    Testing macroecological abundance patterns: The relationship between local abundance and range size, range position and climatic suitability among European vascular plants

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    Aim: A fundamental question in macroecology centres around understanding the relationship between species' local abundance and their distribution in geographical and climatic space (i.e. the multi‐dimensional climatic space or climatic niche). Here, we tested three macroecological hypotheses that link local abundance to the following range properties: (a) the abundance-range size relationship, (b) the abundance-range centre relationship and (c) the abundance-suitability relationship. Location: Europe. Taxon: Vascular plants. Methods: Distribution range maps were extracted from the Chorological Database Halle to derive information on the range and niche sizes of 517 European vascular plant species. To estimate local abundance, we assessed samples from 744,513 vegetation plots in the European Vegetation Archive, where local species' abundance is available as plant cover per plot. We then calculated the 'centrality', that is, the distance between the location of the abundance observation and each species' range centre in geographical and climatic space. The climatic suitability of plot locations was estimated using coarse‐grain species distribution models (SDMs). The relationships between centrality or climatic suitability with abundance was tested using linear models and quantile regression. We summarized the overall trend across species' regression slopes from linear models and quantile regression using a meta‐analytical approach. Results: We did not detect any positive relationships between a species' mean local abundance and the size of its geographical range or climatic niche. Contrasting yet significant correlations were detected between abundance and centrality or climatic suitability among species. Main conclusions: Our results do not provide unequivocal support for any of the relationships tested, demonstrating that determining properties of species' distributions at large grains and extents might be of limited use for predicting local abundance, including current SDM approaches. We conclude that environmental factors influencing individual performance and local abundance are likely to differ from those factors driving plant species' distribution at coarse resolution and broad geographical extents

    Restoration of european habitats in mainland, Portugal, using commercial seed mixtures. Considerations for its management and conservation

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    Permanent mountain pastures include meadows and other perennial pastures of high ecological, economic, cultural and scenic value. Increasing desertification limits the maintenance and conservation of its biodiversity and the associated landscape mosaic. A restoration experiment in permanent high altitude grasslands in Beira Alta (Centre East (CE) mainland Portugal) was made, by sowing adequate cultivars of existing grass and legume species. The main objectives addressed were: (1) comparison of floristic composition between reference communities included in the previous habitats and the improved communities; (2) evaluation of the success of sowing adequate cultivars of autochthonous species; (3) evaluation of the establishment of target species in terms of the maintenance of floristic composition of reference. The experiment was carried out in 2014 on nine farms situated in Beira Alta (Guarda District) and the phytosociological method was applied in the floristic surveys. The sown species with highest percentage of soil cover were Trifolium subterraneum, Lolium multiflorum, Ornithopus sativus and Trifolium vesiculosum. In the priority habitat 6220 it was observed a re-establishment of many species in their original composition and a high cover of several cultivars of Trifolium subterraneum. These results highlight the importance of using cultivars of autochthonous species in the improvement of altitude pasturesinfo:eu-repo/semantics/publishedVersio

    Characterization of the behavior of carotenoids from pitanga (Eugenia uniflora) and buriti (Mauritia flexuosa) during microemulsion production and in a dynamic gastrointestinal system

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    Uncommon tropical fruits are emerging as raw-material for new food products with health benefits. This work aimed at formulating and processing microemulsions from pitanga (Eugenia uniflora) and buriti (Mauritia flexuosa) fruits, since they are very rich in carotenoids (particularly lycopene and -carotene), in order to encapsulate and increase carotenoids bioaccessibility. Pitanga and buriti microemulsions were produced by applying a direct processing (high-speed homogenization at 15,000 rpm and ultrasound with 20 kHz probe at 40% amplitude) of the whole pulp together with surfactant (Tween 80 or Whey Protein Isolate at 2%) and corn oil (5%). All treatments (HSHUS for 04, 40, 44, 48 minmin) applied were able to increase the amount of carotenoid released. However, the processing also decreased the total amount of carotenoids in the whole pulp of studied fruits. The impact of processing during microemulsion production was not severe. The overall data suggest that the presence of surfactant and oil during processing may protect the carotenoids in fruits and microemulsions. Final recovery of total carotenoids, after passing the samples through a dynamic gastrointestinal system that simulates the human digestion, was higher for microemulsions than for whole pulps. High losses of total carotenoids in buriti and -carotene and lycopene in pitanga occurred during jejunum and ileum phases. The present work confirms that it is possible to increase -carotene and lycopene bioaccessibility from fruits by directly processing microemulsions (p<0.01).This work was supported by the São Paulo Research Foundation—FAPESP through research funding [Grant #2015/15507-9] and Ph.D. scholarship for Paulo Berni [Grant #2014/15119-6] and a Research Internships Abroad (BEPE) support [Grant #2016/13355-0]. The author Ana C. Pinheiro is recipient of a fellowship from the Portuguese Foundation for Science and Technology (FCT) [Grant SFRH/BPD/101181/2014]info:eu-repo/semantics/publishedVersio
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