1,720,978 research outputs found
Toxicity of some synthetic pyrethroids to red swamp crayfish (Procambarus clarkii, Girard 1852) and common carp (Cyprinus carpio, L. 1758), in laboratory tests.
No full textMonitoring with ecological indicators in the program of environmental controls in a landfill
No full text
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
Preliminary disease investigations on white-clawed crayfish Austropotamobius pallipes from streams of Northern Italy
No full textRisultati preliminari sullo stato sanitario di popolazioni selvatiche di gambero d’acqua dolce Austropotamobius pallipes del Nord Italia.
No full textNell‟ambito di un progetto finanziato dal Ministero delle Politiche Agricole e Forestali,
finalizzato alla conservazione della specie autoctona di gambero d‟acqua dolce
Austropotamobius pallipes, sono state condotte indagini sanitarie su popolazioni selvatiche
del nord Italia, allo scopo di valutare la presenza di eventuali patologie di natura parassitaria,
micologica e batteriologica. Un totale di 102 gamberi d‟acqua dolce sono stati catturati
durante l‟autunno 2003 da 5 diversi corsi d‟acqua del dell‟Emilia Romagna e del Friuli
Venezia Giulia. Una parte degli animali (58 soggetti) è stata utilizzata per verificare la
possibilità di riprodurre ed allevare la specie in ambiente controllato per la produzione di
materiale da utilizzare in azioni di ripopolamento, mentre, su 44 gamberi sono state eseguite
indagini parassitologiche, micologiche e batteriologiche. Gli esami parassitologici sono stati
effettuati a fresco su porzioni di branchie, intestino e muscolo addominale; le indagini
micologiche attraverso la semina in terreni di coltura specifici di porzioni di esoscheletro di
zampe e cuticola addominale che presentavano lesioni; gli esami batteriologici da prelievi di
emolinfa seminati su terreni di coltura. Su tutti i soggetti sottoposti ad indagini sanitarie sono
state eseguite osservazioni anatomopatologiche ed istologiche da sezioni di cefalotorace ed
addome colorate mediante Ematossilina Eosina, Giemsa e PAS.
Nelle osservazioni a fresco si rilevava la sola presenza di protozoi peritrichi ectocommensali
appartenenti ai generi Epystilis e Cothurnia, presenti nella camera branchiale e sui filamenti
delle branchie e la presenza di branchiobdellidi. Fusarium sp. e Saprolegnia parasitica sono
stati isolati da alcune lesioni della cuticola, mentre ifomiceti ialini e dematiacei venivano
riscontrati frequentemente. Nell‟emolinfa di soggetti vivi e moribondi: le specie batteriche più
frequentemente isolate risultavano Citrobcter freundii e Aeromonas hydrophila. Vengono
riportati i risultati delle osservazioni anatomo-istopatologiche
Evaluation of the toxicity of synthetic pyrethroids to red swamp crayfish (Procambarus clarkii, Girard 1852) and common carp (Cyprinus carpio, L. 1758)
Full text linkThe acute toxicity of three synthetic pyrethroids (Cypermethrin, Deltamethrin and Cyfluthrin) to red swamp crayfish (Procambarus clarkii) and the mortality after long-term exposition of young common carp to Deltamethrin were determined in standardized laboratory tests.
The aim of this study was to evaluate the possibility of limiting the expansion of crayfish by the use of these compounds and the implications of their use on fish.
Red swamp crayfish experienced high sensitivity to pyrethroids as expressed by the LC50-24h: 0.14 mu g/l for Cypermethrin, 0.17 mu g/l for Cyfluthrin and 0.22 mu g/l for Deltamethrin. No mortality was observed in common carp during the long term (24 days) exposure test at initial concentration of 22.0 mu g/1 of Deltamethrin. The concentrations of Deltamethrin in muscle of crayfish and common carp were under the limit of quantification of the gas-chromatographic method in all the tests.
The results suggest that synthetic pyrethroids may be suitable to control or to eradicate nuisance populations of red swamp crayfish, in small and limited areas
Fungal infections in allochthonous freshwater crayfish in northern Italy.
No full textA mycological study, involving Aphanomyces astaci, was carried out on allochthonous freshwater crayfish, which are increasing in number in the streams of Northern Italy. A. astaci is the agent of the crayfish plague a disease which has devastated many European native populations of freshwater crayfish. It appears that this disease is endemic to North America and that the higher resistance of the North American species is a result of the coevolution of both the fungus and the host. The North American crayfish carry this fungus as a chronic infection in melanized spots in their cuticle.
Small pieces of the exoskeleton of 12 specimens of red swamp crayfish Procambarus clarkii (Girard), coming from the canals of the province of Bologna, and of 2 signal crayfish Pacifastacus leniusculus (Dana), coming from the Auenbachl stream in the province of Bolzano, were placed in plates containing glucose-yeast extract agar with penicillin and oxolinic acid and incubated at room temperature.
Fusarium spp. was recovered from a total of 9 crayfish of the above-mentioned species; it was most frequently isolated from brown lesions of the exoskeleton (Burn spot disease).
Dictyuchus sp was isolated from cottonwool-like tufts in one P.clarkii.
An oomycete with morphological characteristics resembling A. astaci was found in one specimen of red swamp crayfish.
The role played by fungi in the pathologies of freshwater crayfish is briefly 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
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