110 research outputs found

    Integrating an individual-based model with approximate Bayesian computation to predict the invasion of a freshwater fish provides insights into dispersal and range expansion dynamics

    Get PDF
    Short-distance dispersal enables introduced alien species to colonise and invade local habitats following their initial introduction, but is often poorly understood for many freshwater taxa. Knowledge gaps in range expansion of alien species can be overcome using predictive approaches such as individual based models (IBMs), especially if predictions can be improved through fitting to empirical data, but this can be challenging for models having multiple parameters. We therefore estimated the parameters of a model implemented in the RangeShifter IBM platform by approximate Bayesian computation (ABC) in order to predict the further invasion of a lowland river (Great Ouse, England) by a small-bodied invasive fish (bitterling Rhodeus sericeus). Prior estimates for parameters were obtained from the literature and expert opinion. Model fitting was conducted using a time-series (1983 to 2018) of sampling data at fixed locations and revealed that for 5 of 11 model parameters, the posterior distributions differed markedly from prior assumptions. In particular, sub-adult maximum emigration probability was substantially higher in the posteriors than priors. Simulations of bitterling range expansion predicted that following detection in 1984, their early expansion involved a relatively high population growth rate that stabilised after five years. The pattern of bitterling patch occupancy was sigmoidal, with 20 % of the catchment occupied after 20 years, increasing to 80 % after 30 years. Predictions were then for 95 % occupancy after 69 years. The development of this IBM thus successfully simulated the range expansion dynamics of this small-bodied invasive fish, with ABC improving the simulation precision. This combined methodology also highlighted that sub-adult dispersal was more likely to contribute to the rapid colonisation rate than expert opinion suggested. These results emphasise the importance of time-series data for refining IBM parameters generally and increasing our understanding of dispersal behaviour and range expansion dynamics specifically

    Empirical analyses of the length, weight, and condition of adult Atlantic salmon on return to the Scottish coast between 1963 and 2006

    Get PDF
    Sea age, size, and condition of adult Atlantic salmon (Salmo salar) are prime determinants of individual, and hence population, productivity. To elucidate potential mechanisms, 151 000 records of salmon returning to six Scottish coastal sites over 44 years were analysedfor length, weight, and condition, by site, sex, sea age, and river age. After correcting for capture effort biases, all sites showed seasonal increases in length and weight for both 1 sea winter (1SW) and 2SW fish. However, whereas condition increased slightly with season for 2SW, it decreased notably for 1SW. Sites showed common decadal trends in length, weight, and condition. Within years, length and weight residuals from trends were coherent across sites, but residuals from condition trends were not. Rates of seasonal condition change also showed decadal trends, dramatically different between sea ages, but common across sites within sea-age groups. Longer salmon were disproportionately heavy in all seasons. 1SW condition was markedly lower in 2006. Detrended correlations withoceanic environmental variables were generally not significant, and always weak. A published correlation between the condition of 1SW salmon caught at a single site and sea surface temperatures in the Northeast Atlantic could not be substantiated for any of the six fisheries over the wider time-scales examined

    Impregnação de amostras de solo com "polylite 8001"

    Get PDF
    A method for the impregnation of soil samples with the polyester resin Polylite 8001, is described. The best combination of resin, solvent and catalyst was 70% of resin, 30% of styrene monomelic and 8 drops of methyl-ethyl-ketone peroxide per 100 ml of resin.O trabalho descreve a impregnação de amostras de solo utilizando a resina poliéster Polylite 8001, com a posterior finalidade de preparo de seções delgadas. Dentre as várias proporções examinadas entre resina, monômero de estireno (solvente) e peróxido de metil-etil-cetona (peróxido de MEK; catalisador), a de 70% de resina, 30% de monômero e 8 gotas de catalisador para cada 100 ml de resina, foi achada ser a melhor. Um produto impregnado de elevada dureza, isótropo sob luz polarizada e que não alterou a estrutura das amostras, são algumas das vantagens dessa resina sobre outros tipos

    First isolation of dengue 1 virus from Aedes aegypti in Federal District, Brazil

    Get PDF
    Dengue is present in the Federal District since 1991 and virological studies of the vector began in 1998. Two strains of DEN1 were isolated from 9 pools of female Aedes aegypti (78 mosq.), collected in April in Gama county, where the Breteau index was 5.4, and 32 autochtonous human cases were notified

    A Educação Do Corpo Nos Parques E Recantos Infantis De Campinas-sp (1940-1959)

    Get PDF
    The study aimed to show discourses and practices articulated around body education in parks and playgrounds in the city of Campinas in 1940-1959. Through historical research, it concludes that children’s parks and playgrounds were important institutions for care, education, culture and recreation for children, designed and oriented as a political and educational project to control children, but also to establish local and national identities still not consolidated as modern, urban and rational. © 2016, Universidade Federal do Rio Grande do Sul. All rights reserved.22370772

    Substratos De Fibra De Coco Granulada E Casca De Arroz Para A Produção Do Morangueiro ‘oso Grande’

    Get PDF
    The strawberry, when grown in soil, becomes susceptible to fungi present on it. Rotations of planted areas are essential to control disease, reality unworkable for some Brazilian farmers who have small areas for cultivation. This problem encouraged the use of substrates, a technical pattern already well-established in Europe. The objective was to assess the response of strawberry growth (‘Oso Grande’) on three substrates (granulated coconut fiber, pure rice husk and a mixture of both in equal proportions), volumes (1.0; 1.5 and 2.0 L) and irrigation frequencies (twice, three and four times a day). The experiment was carried out in a greenhouse in Jundiaí (SP), from July 2 to October 4, 2010. The data were submitted to the joint analysis of experiments, in a triple factorial scheme (irrigation frequencies, substrate types and substrate volumes). The best result obtained occurred for substrate mixture, with the irrigation frequency of three times a day, in 1.0 L of the material, with an average yield of 223 g per plant. Rice husk is ineffective for cultivation in pots. Nevertheless, in the form of mixtures, this substrate is suited for cultivation, allowing better results when compared to granulated coconut fiber. © 2016, Instituto Agronomico. All rights reserved.75222222

    An exploratory study into the role and interplay of intrinsic and extrinsic cues in Australian consumers’ evaluations of fish.

    Get PDF
    This study explores the role and interplay of intrinsic and extrinsic cues when evaluating fish quality and in shaping consumers' attitudes toward fish consumption. A sensory analysis of nine different fish including five variants of barramundi was conducted to determine how consumers evaluated the fish on intrinsic cues. Focus groups were then conducted to explore the impact of extrinsic cues on attitudes and purchase intentions. While the sensory analysis revealed distinct differences between barramundi variants on intrinsic cues (notably taste), the focus groups revealed that, as a brand, barramundi is perceived much more favourably and consistently. Consumers used extrinsic cues, particularly country of origin, as surrogate indicators of quality. Aquaculture producers need to ensure intrinsic product quality and consistency, as while consumers use the extrinsic cue of "Australian grown" as a surrogate indicator of quality, as their familiarity and confidence with seafood grows, this overreliance on extrinsic cues may diminish
    corecore