1,720,958 research outputs found
Humboldt penguins’ feathers as bioindicators of metal exposure
No full textAvian feathers have the potential to accumulate trace elements originating from contaminated food and polluted environments. In fact, in feathers, metals bind to keratin, a sulphur-containing protein for which several metals have a strong affinity. Here, the concentrations of 18 essential and non-essential elements were investigated in a Humboldt penguin (Spheniscus humboldti) colony housed at the Acquario di Cattolica (Italy). This species is listed as vulnerable in the Red List of the International Union for Conservation of Nature. According to the literature, there is usually a link between metal levels in the diet of birds and levels detected in their feathers. Thus, metals were also determined in the penguins’ food (capelin, Mallotus villosus). We hypothesize that the controlled conditions in which birds are kept in captivity, and the homogeneous diet that they follow could allow a better understanding of metal bioaccumulation (such as mercury) or bio-dilution (such as arsenic) in the marine food chain, indicated by penguins’ feathers. Moreover, comparisons with our previous investigations performed on an ex-situ African penguin (Spheniscus demersus) colony suggest that penguins living indoors have lower body burden of metals than those living outdoors. Indeed, environmental contaminants usually found in areas subjected to anthropogenic impact, where zoos and aquaria are often located, are not accumulated to levels of concern
Systemic infection by Vibrio harveyi in humphead wrasse Cheilinus undulatus (Rüppell, 1835) at a public aquarium
No full textThe humphead wrasse, Cheilinus undulatus, also known as Napoleon wrasse or Maori, is one
of the giant coral reef fish of the Indo-Pacific Area. In public aquaria C. undulatus is
frequently exhibited for its huge body size, longevity and as a conservation ambassador of
reef ecosystems. The knowledge about diseases of this precious and rare fish species is very
limited and only a few disorders have been reported in literature.
In May 2008 one humphead wrasse was introduced to the Cattolica Aquarium, Italy and
exhibited in a 56,000 l tank together with a mixed population of teleosts, sharks and rays. In
February 2017 the fish, weighing 15 kg, died and no clinical signs were observed in the days
before its death. The fish was immediately necropsied and standard parasitological,
bacteriological and histological exams were carried out in order to investigate causes of
death.
At necropsy, fish showed slightly pale gill and the presence of a severe fibrinous peritonitis.
In the posterior part of the kidney, a diffuse area of necrosis with suppurative-like aspect was
also observed. No gross lesions were noticed in other organs and no parasites have been
found both macro and microscopically. After 24 h of incubation at 25±1°C, from all the
inoculated organs (kidney, spleen, liver and brain) a number of morphologically similar
colonies grew on TSA+1.5% NaCl and TCBS plates respectively. The isolates were
identified as Vibrio harveyi and antibiotic sensitivity test was performed by Kirby-Bauer disk
diffusion method. Histological exams showed the presence of bacterial aggregatesassociated
to necrosis in most of the internal organs, especially in the kidney. Macrovacuolar liver
steatosis was also observed. Furthermore several elongated fungal hyphae were found only in
liver blood vessels.
This case is to our knowledge the first report of systemic infection by Vibrio harveyi in a
humphead wrasse and highlights the potential pathogenic role of these microorganisms in fish
kept under confined condition
Reproduction and restocking activities to reintroduce adriatic sturgeon in its natural areas
No full textFeathers of Humboldt penguin are suitable bioindicators of Rare Earth Elements
No full textRare earth elements (REEs), also called lanthanides, are emerging contaminants worldwide, due to their unique physical and chemical characteristics that make them essential in a variety of industrial applications. However, there is still a gap in the knowledge of occurrence and accumulation of REEs in biota, and no investigations have yet been performed in penguin feathers, which have already been widely utilized as a non-invasive tool for the biomonitoring of trace elements. The concentrations of 16 REEs were investigated in a colony of Humboldt penguins (Spheniscus humboldti)housed at the Acquario di Cattolica (Italy). Multielement determination of REEs was performed by an Inductively Coupled Plasma-Mass Spectrometer after a microwave digestion of feathers. As this colony lives indoors in a controlled environment, it was the ideal choice for studying lanthanide occurrence in penguin feathers. Since there is a strict link between metal levels in feathers and the diet of penguins, their food (capelin)was also tested for REEs. Chondrite normalized values revealed the same pattern for REEs in feathers and fish, but REE concentrations were an order of magnitude higher in penguin feathers, demonstrating the suitability of this tissue as a bioindicator of REEs
Episodio di setticemia da Photobacterium damselae subsp. damselae in pesci violino (Rhinobatos rhinobatos) mantenuti in ambiente controllato.
No full textIl pesce violino Rhinobatos rhinobatos è un pesce cartilagineo appartenente al gruppo delle razze della famiglia Rhinobatidae. In natura è presente nell'Atlantico orientale e in tutte le coste del Mediterraneo. Questi elasmobranchi sono noti per il loro caratteristico aspetto, a ponte tra squali e razze, e svolgono un ruolo cruciale negli ecosistemi marini, contribuendo al mantenimento di reti trofiche marine naturali. A causa della forte pressione della pesca, con frequenti catture accidentali, il pesce violino è una specie in declino nel Mar Mediterraneo ed il suo mantenimento in acquari o parchi zoologici rappresenta una strategia per assicurarne la sopravvivenza a fini educativi e di conservazione. Fra le diverse segnalazioni di malattie trasmissibili degli elasmobranchi mantenuti in ambienti controllati, poche riguardano il pesce violino, solitamente considerato una specie adattabile e robusta.
Scopo di questo lavoro è stato quello di individuare le cause di un episodio di mortalità verificatosi in tre pesci violino di circa 20 anni d’età stabulati da diversi anni presso un acquario pubblico. I pesci sono morti improvvisamente dopo aver mostrato, il giorno prima della morte, sintomi aspecifici di tipo respiratorio e atassia natatoria.
Dopo la morte, gli esemplari sono stati immediatamente inviati all'Unità di Ittiopatologia del DIMEVET e sottoposti ad esami necroscopici, batteriologici, parassitologici e istologici secondo metodi standard di laboratorio. È stata inoltre effettuata la RT-PCR per ricerca di Betanodavirus.
All'esame necroscopico, i pesci esternamente mostravano emorragie diffuse sulle pinne e nella parte ventrale del corpo, mentre all’apertura della cavità corporea era possibile rilevare una grave enterite emorragica.
L'esame batteriologico ha permesso di isolare in purezza da cervello, rene, milza, cuore, fegato e intestino di tutti gli esemplari esaminati Photobacterium damselae subsp. damselae. L’identificazione è stata condotta mediante Maldi-TOF (Bruker) e confermata tramite PCR e sequenziamento. Le analisi parassitologiche e la RT-PCR per ricerca di Betanodavirus sono risultate negative.
All'esame istologico sono state osservate evidenti alterazioni a livello delle branchie, con grave congestione delle lamelle, edema, sfaldamento e necrosi, del cuore, con congestione delle arterie coronarie e presenza di aggregati batterici con necrosi diffusa e gravi emorragie atriali e miocardiche, e del rene, dove i tubuli presentavano dilatazione e necrosi focale con presenza di aggregati batterici, unitamente a degenerazione a goccioline ialine e vacuolare a carico delle cellule epiteliali. Sono state rilevate anche lieve congestione epatica e necrosi focale nella milza, con presenza di aggregati batterici nel lume dei vasi. Nell’insieme i risultati dell'esame istopatologico erano riferibili ad una setticemia di origine batterica in tutti e tre gli esemplari.
P. damselae subsp. damselae è un batterio marino appartenente alla famiglia Vibrionaceae in grado di causare malattia in pesci, crostacei, molluschi e cetacei. Ubiquitario nell'ambiente acquatico, è stato isolato da diversi substrati e matrici biologiche nonché da animali marini apparentemente non infetti, ed è considerato un comune componente del microbiota naturale degli squali carcarinidi. Inoltre, è considerato un patogeno primario di specie ittiche selvatiche, fra cui squali e razze, ed un patogeno emergente di specie ittiche di rilievo in acquacoltura, soprattutto in presenza di condizioni stressogene.
L’episodio qui descritto rappresenta il primo caso di mortalità a causa di setticemia da P. damselae subsp. damselae in pesci violino mantenuti in ambiente controllato e vuole essere un contributo al miglioramento delle conoscenze sugli agenti patogeni che possono minacciare il benessere e la sopravvivenza di questa specie ittica, considerata attualmente “in pericolo critico” (CR) dalla IUCN
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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