1,720,988 research outputs found
Environmental risk assessment of antibacterial agents using an in vitro test
No full textAlgal toxicity of antibacterial agents used in intensive farming was investigated. The growth-inhibiting effects of oxytetracycline (OTC), sulphametazine (SMZ) and tylosin (TYL) were investigated by a modified test procedure based on the procedure described in the ISO 8692 (1989) protocol on the freshwater green alga Selenastrum capricornutum. Algal growth was measured as increased chlorophyll concentration. The chlorophyll was extracted with ethanol and fluorometrically determined. Results were quantified in terms of growth rates using Weibull equation to describe the concentration response relationship. The toxicity (EC50 value, mg/l) were: OTC, 4,17; SMZ, 10,7;TYL, 0,949, respectively
Studio mediante sistemi in vitro e HPLC delle differenze specie specifiche dei metaboliti idrossilati del Testosterone
No full textSUMMARY - A preliminary study was performed to investigate by HPLC analyses the metabolism of testosterone to various hydroxylated metabolites by using liver microsomal preaparation obtained from different veterinary species. The analytical method was able to identify and quantify the various TST-metabolites produced. Different production of the metabolites was observed among the different veterinary species considered
Dispersione di ossitetraciclina nell'ambiente in seguito a trattamento dei vitelli
No full textDopo aver trattato dei vitelli con 60 mg/kg di ossitetraciclina per cinque giorni, il farmaco e' stato rintracciato nelle feci, nella lettiera e nel letame. Il tempo di cinque mesi necessario per la maturazione del letame consente una degradazione adeguata ed e' sufficiente per minimizzare l'impatto ambientale del farmac
Identificazione dei metaboliti prodotti in vitro di un nuovo beta-agonista mediante cromatografia liquida/spettrometria di massa (LC/MS/MS)
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Ricerca di Torque Teno Virus (TTV) in suini allevati in Italia
No full textI Torque Teno Virus (TTV) appartengono ad un genere di ancora
incerta classificazione definito Anellovirus. I TTV sono stati messi in evidenza per la prima volta nell’uomo nel 1997, in un paziente con epatite post-trasfusionale ad eziologia sconosciuta. Recentemente, TTV non distinti geneticamente da quelli messi in evidenza nell’uomo sono stati riscontrati anche negli animali, suini inclusi. Il presente lavoro ha avuto lo scopo di stimare la prevalenza dell’infezione da TTV in allevamenti italiani di suini e valutare i possibili fattori di rischio relativi all’infezione. Campioni di siero prelevati da 179 suini clinicamente sani di 10 aziende situate in Italia Centro-Settentrionale sono stati esaminati mediante PCR per la ricerca del DNA di TTV. DNA virale è stato evidenziato nel siero di
43 suini (24%), provenienti da 8 dei 10 allevamenti esaminati. La prevalenza è risultata essere significativamente più elevata nelle aziende da ingrasso (40,1%) che in quelle da riproduzione-ingrasso (11%) e non correlata alle dimensioni aziendali. Negli allevamenti da ingrasso, la prevalenza è risultata significativamente più elevata nei magroni (57,4%) che nei grassi (22,9%), ma tale differenza non è stata osservata negli allevamenti da riproduzione-ingrasso.
L’implementazione di alcune misure di profilassi igienico-sanitaria e di biosicurezza, valutate nel presente studio, non sembra essere in relazione con la prevalenza di TTV
Use of oxytetracycline and tylosin in intensive calf farming: evaluation of transfer to manure and soil
No full textAntibiotics may enter soils with manure from treated animals. Because of their biological effects, antibiotics are regarded as potential micropollutants. The levels of oxytetracycline and tylosin over time were followed in faeces, bedding and manure, and then in the soil of a manured field and surrounding drainage courses, after oral treatment of calves. Fifty Simmental calves were treated for 5 days with 60 mg/kg/day of oxytetracycline. After 15 days the animals were treated for 5 days with 20 mg/kg/day of tylosin. Tylosin degraded rapidly, and was no longer detected in manure 45 days after cessation of treatment and no trace of the compound was detected in soil or surrounding water (detection limits 10 microg/l). The half-life of oxytetracycline in manure was 30 days and the compound was still detectable in this matrix (820 microg/kg) after 5 months maturation. In the manured soil oxytetracycline was detected at concentrations at least 10 times lower than the European Agency for the Evaluation of Medicinal Products threshold (100 microg/kg) requiring phase II environmental risk assessment. Oxytetracycline was not detected in the water courses (detection limit 1 microg/l). These results demonstrate that the processes occurring between faeces production and application of manure to the soil are very effective in reducing the load of TYL and OTC in the environment. For both drugs a toxicity test was performed using the alga Selenastrum capricornutum. The EC50 was 4.18 mg/l for oxytetracycline and 0.95 mg/l for tylosin. A worst-case hazard assessment for the aquatic environment was performed comparing the ratio between the measured concentrations (LOD) and effect data from previous work (OTC) or from this work (TYL). This showed ratio between toxicity levels (bacteria) (EC50=0.14 mg/l) and measured concentrations (LOD=1 microg/l) for OTC to be 140. The corresponding value for TYL (LOD=10 microg/l) was 9
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