35 research outputs found

    On the RIP: using Relative Impact Potential to assess the ecological impacts of invasive alien species

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    Invasive alien species continue to arrive in new locations with no abatement in rate, and thus greater predictive powers surrounding their ecological impacts are required. In particular, we need improved means of quantifying the ecological impacts of new invasive species under different contexts. Here, we develop a suite of metrics based upon the novel Relative Impact Potential (RIP) metric, combining the functional response (consumer per capita effect), with proxies for the numerical response (consumer population response), providing quantification of invasive species ecological impact. These metrics are comparative in relation to the eco-evolutionary baseline of trophically analogous natives, as well as other invasive species and across multiple populations. Crucially, the metrics also reveal how impacts of invasive species change under abiotic and biotic contexts. While studies focused solely on functional responses have been successful in predictive invasion ecology, RIP retains these advantages while adding vital other predictive elements, principally consumer abundance. RIP can also be combined with propagule pressure to quantify overall invasion risk. By highlighting functional response and numerical response proxies, we outline a user-friendly method for assessing the impacts of invaders of all trophic levels and taxonomic groups. We apply the metric to impact assessment in the face of climate change by taking account of both changing predator consumption rates and prey reproduction rates. We proceed to outline the application of RIP to assess biotic resistance against incoming invasive species, the effect of evolution on invasive species impacts, application to interspecific competition, changing spatio-temporal patterns of invasion, and how RIP can inform biological control. We propose that RIP provides scientists and practitioners with a user-friendly, customisable and, crucially, powerful technique to inform invasive species policy and management

    Avaliação da sensibilidade da cultura de leite do tanque para isolamento de agentes contagiosos da mastite bovina Evaluation of the sensitivity of bulk tank milk cultures for the isolation of contagious bovine mastitis pathogens

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    Amostras de leite total (leite do tanque) de 33 rebanhos foram coletadas na plataforma de recepção da indústria laticinista e cultivadas para detectar patógenos específicos (contagiosos) da mastite. Foi feita a contagem de células somáticas (CCS) das amostras utilizando o equipamento Fossomatic 90. Em 13 e 12 rebanhos avaliaram-se duas e três amostras semanais consecutivas, respectivamente, e em oito avaliou-se apenas uma. Foram também examinadas três amostras diárias consecutivas do leite do tanque e amostras dos quartos mamários individuais, coletadas na própria fazenda, de todas as vacas em lactação de quatro rebanhos (A, B, C e D). As amostras de leite dos quartos mamários individuais foram cultivadas em ágar sangue e as amostras do tanque, em placas de TKT, Sal Manitol, MacConkey e Sabouraud contendo cloranfenicol. Dos 33 rebanhos cujas amostras foram obtidas na plataforma de recepção da indústria, isolou-se Staphylococcus aureus de 26, nove desses em associação com Streptococcus agalactiae e em três rebanhos isolou-se somente S. agalactiae. Nove rebanhos tiveram CCS acima de 500.000 ml-1 e 21, abaixo de 400.000 ml-1. Em cinco dos nove rebanhos com CCS acima de 500.000 ml-1 foram isolados S. aureus e S. agalactiae, em três, apenas S. aureus e em um, apenas S. agalactiae. Seis rebanhos apresentaram CCS abaixo de 200.000 ml-1; de um deles foram isolados S. aureus e S. agalactiae, de três, S. aureus e os outros dois foram negativos para estes dois patógenos. Os resultados encontrados nos quatro rebanhos cujas amostras foram coletadas na própria fazenda mostraram que S. aureus foi isolado nas seguintes porcentagens dos animais: 1,8%, 19,2%, 17,0% e 8,4% e dos quartos mamários: 0,9%, 5,9%, 5,4% e 2,2%, respectivamente, para os rebanhos A, B, C e D. S. agalactiae foi isolado dos rebanhos A, C e D. Nestes três rebanhos, as porcentagens de isolamento foram, respectivamente, 1,8%, 10,6% e 8,4% para as vacas e 0,46%, 3,8% e 3,7% para os quartos mamários. S. aureus foi isolado de todas três amostras do tanque dos rebanhos A, B e D. Somente a terceira amostra do rebanho C foi positiva para S. aureus. S agalactiae foi recuperado de todas as amostras do rebanho D, duas do rebanho C e de uma do rebanho A. Todas as amostras do tanque dos rebanhos A, B, C e D apresentaram contaminação com coliformes e somente uma das amostras coletadas na plataforma de recepção da indústria foi negativa para coliformes. Leveduras foram isoladas de 16 amostras coletadas na indústria e de todas amostras do tanque dos rebanhos A, B, C e D. Não foram isolados coliformes ou leveduras dos quartos mamários dos animais destes rebanhos, sugerindo que ocorreu contaminação do leite durante ou após a ordenha, provavelmente devido a deficiências nos processos de limpeza e higienização. A análise dos resultados das culturas do leite do tanque mostrou que o exame foi específico para detectar os patógenos contagiosos da mastite. A sensibilidade do teste aumentou quando se examinaram mais de duas amostras consecutivas.<br>Samples of bulk tank milk from 33 herds were collected at the dairy processing plant and cultured, as a means of detecting specific (contagious) bovine mastitis pathogens. Somatic cell counts (SCC) were made on a Fossomatic 90. Two and three weekly consecutive samples were obtained from 13 and 12 herds, respectively. Only one sample was examined from eight herds. Three daily consecutive samples of bulk milk and individual quarter samples from all lactating cows from four herds (A, B, C and D) were also examined. Milk from individual quarters were cultured on blood agar, while tank milk samples were cultured on TKT, Mannitol Salt, MacConkey agars and Sabouraud containing chloramphenicol. Staphylococcus aureus was recovered from 26 of the 33 herds sampled in the dairy processing plant. Nine of these samples also contained Streptococcus agalactiae. Nine herds had SCC above 500,000 ml-1. The remaining 23 herds had SCC levels below 400,000 ml-1. S. aureus and S. agalactiae were isolated from five of the nine herds with high SCC, S. agalactiae from one and S. aureus from three. Six herds had SSC below 200,000 ml-1. S. aureus and S. agalactiae were isolated from one, S. aureus from three, while the other two were negative for both pathogens. The results of herds A, B, C and D sampled at the farms showed that S. aureus was isolated from 1.8%, 19.2%, 17.0% and 8.4% of the animals and 0.9%, 5.9%, 5.4% and 2.2% of the mammary quarters, respectively. S. agalactiae was isolated from herds A, C and D. Within these herds the percentages of isolation were, respectively, 1.8%, 10.6% and 8.4% for the cows and 0.46%, 3.8% and 3.7% for the mammary quarters. S. aureus was recovered from all three bulk tank cultures from herds A, B and D. Only the third sample from herd C was positive for S. aureus. S. agalactiae was recovered from all samples collected from herd D, two samples from herd C and one sample from herd A. Coliforms were isolated from all tank samples from herds A, B, C and D and from all but one sample collected in the processing plant. Yeasts were recovered from 16 herds sampled at the processing plant and from all tank samples from herds A, B, C, and D. Neither coliforms or yeasts were isolated from the individual animals of herds A, B, C and D. These findings indicate that the milk was contaminated during or after milking, probably due to deficient hygiene and cleaning procedures. The analysis of the bulk tank milk cultures showed that the test was sensitive enough to detect contagious mastitis pathogens. The sensitivity of the test increased when more than two consecutive samples were examined

    Synchrotron Radiation and Faraday Rotation

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    Synchrotron radiation and its degree of linear polarization are powerful tracers of magnetic fields that are illuminated by cosmic ray electrons. Faraday rotation of the linearly polarized radiation is induced by intervening line-of-sight magnetic fields that are embedded in ionized plasmas. For decades these observational tools have been workhorses for utilizing radio telescopes to study magnetic fields inside and outside the Milky Way. In the modern era they are becoming still more powerful with the advent of broadband receiving systems on the current generation of radio telescopes. In the study of Faraday rotation in particular, rapid development is taking place in techniques to confidently recover the physical conditions of the magnetoionized medium in the Milky Way and extragalactic objects
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