1,720,982 research outputs found
Libellule di Liguria
No full textQuesto lavoro aggiorna le conoscenze sugli Odonati presenti all’interno del
territorio della Regione Liguria (Italia nord-occidentale) a quasi 70 anni dall’ultimo contributo a scala regionale (Capra 1945). Lo studio è stato realizzato sia attraverso la consultazione della bibliografia a disposizione e di alcune collezioni museali sia
attraverso la raccolta di nuovi dati.
In totale sono state raccolte circa 3000 osservazioni con una copertura
regionale media di circa un’osservazione ogni 2 Kmq. Tra questi dati circa 500
sono bibliografici e oltre 2500 inediti, questi ultimi raccolti in gran parte (88%)
negli ultimi 7 anni. Nel complesso sono state radunate segnalazioni per 57 specie,
23 Zigotteri e 34 Anisotteri.
Rispetto ai dati bibliografici sono state osservate 4 specie nuove per la Liguria:
Coenagrion pulchellum, Ophiogomphus cecilia, Libellula fulva e Trithemis annulata.
Non sono state invece ritrovate recentemente 5 specie segnalate storicamente:
Coenagrion mercuriale, Erythromma najas, Sympetrum vulgatum, Somatochlora
flavomaculata e Somatochlora meridionalis. Le aree di maggiore interesse o per
motivi biogeografici o per numero totale di specie sono situate nell’Appennino
Genovese (Val d’Aveto, Roccagrande e Valle dell’Orba), nel versante padano a
cavallo tra le province di Genova e Savona (Valle Stura e Valle Erro), nella Valle
Bormida e nel ponente (bacino del Fiume Centa, alta Valle Tanaro e Val Roja)
Nuovi dati sui Cestodi parassiti dei Pletodontidi europei: contributo per una revisione zoogeografica e sistematica
No full textle informazioni sia sulla sistematica sia sulla biologia dei cestodi che inte-
ressano gli anfibi europei sono molto limitate, e fino a poco tempo fa era
noto un unico genere: Nematotaenia luhe, 1910 (ricci, 1988). Buriola et
al. (2002; 2005) confrontando cestodi provenienti da esemplari parassita-
ti di Speleomantes strinatii nell’appennino genovese (liguria centrale), ha
evidenziato come da un punto di vista morfologico ed anatomico i cestodi
apparterrebbero al contrario al genere Distoichometra Dickey, 1921. Tale
genere risultava segnalato solo in anuri e Pletodontidi nordamericani con la
specie D. bufonis Dickey, 1921 e pertanto gli individui parassiti provenienti
dalla liguria furono ascritti ad una nuova specie: Distoichometra. italica Bu-
riola, Pastorino & Bona 2005. nell’ottobre 2015 è stato possibile eseguire
l’analisi di esemplari di S. strinatii provenienti da due popolazioni note in
Valle scrivia (ge): Isola del Cantone e s. Bartolomeo. ai geotritoni è stata
applicata la metodologia non invasiva di raccolta dei parassiti gastrointesti-
nali già ampiamente sperimentata (De Martini et al., 2006), isolando i sin-
goli esemplari in contenitori separati e somministrando loro circa 0,25mg/g
di una sospensione a base di niclosamidae, in singola dose per via orale.
ogni animale è stato quindi controllato ogni ora per verificare la presenza
di parassiti espulsi attraverso il rigurgito, successivamente preparati in la-
boratorio. la sperimentazione è avvenuta su 74 geotritoni, ottenendo 57
esemplari di cestodi in diversi stadi di sviluppo. l’analisi morfometrica e
anatomica degli esemplari, ha evidenziato una notevole plasticità e variabi-
lità negli organi riproduttivi di questi animali, questo renderebbe pertan-
to meno affidabile l’utilizzo dell’apparato paruterino nella discriminazione
specifica se si hanno pochi esemplari a disposizione, mentre quella generica
può basarsi anche solo su poche proglottidi gravide. Ciò ha portato ad una revisione del materiale di N. minor ricci, 1988 in cui erano evidenti tali
proglottidi, portando ad una nuova collocazione nel genere Distoichometra.
Il problema della classificazione sistematica specifica ha messo in evidenza la
necessità di avere a disposizione molto materiale prelevato da siti diversi in
periodi differenti se si vuole evitare il rischio di classificazioni parziali basate
su pochi campioni e la necessità di un confronto con materiale osservabile
anche delle specie tipo in quanto i dati della letteratura spesso non sono
esaustivi
Land abandonment may reduce disturbance and affect the breeding sites of an Endangered amphibian in northern Italy
No full textAlthough human-related disturbance is usually detrimental for biodiversity, in some instances it can simulate natural processes and benefit certain species. Changes in the disturbance regime, both natural and human-driven, can affect species that rely on it. The Apennine yellow-bellied toad Bombina variegata pachypus, an amphibian endemic to peninsular Italy, has declined throughout its range in the last 3 decades. We sought to identify the drivers of the decline in the region of Liguria, at the north-western limit of its distribution. In 2009 and 2010 we surveyed sites where the species occurred until 2005 and related the persistence of breeding activity to the characteristics of sites. Populations had disappeared from 50% of the sites between 2005 and 2009. Current breeding sites have less aquatic and bank vegetation, fewer predators and better insolation. Frequent disturbance events (desiccation and floods) were related to reduced vegetation, which in turn may decrease predator densities and increase insolation. In this region disturbance is provided by natural factors or, in the case of artificial water bodies, by regular maintenance carried out by landowners. The widespread land abandonment in Liguria can disrupt disturbance regimes, interrupting the removal of vegetation, and thus rapidly reduce the suitability of artificial sites. This was confirmed in our study, with most abandoned breeding sites occurring in formerly cultivated areas. Possible short-term conservation actions include creating new ponds, maintaining artificial water bodies and clearing vegetation. However, long-term conservation may be more problematic as the land abandonment process is unlikely to be reversed
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
Posthatching Parental Care in Salamanders Revealed by Infrared Video Surveillance
No full textPosthatching parental care is known in amphibians for frogs and caecilians but, thus far, has never been reported for salamanders. Here, we describe the parental behavior of a female Northwest Italian Cave Salamander, Speleomantes strinatii, from egg deposition to nest site abandonment. The female was kept in seminatural conditions and filmed in complete darkness by an infrared video camera. In November 2007, the female laid nine eggs in a small depression of the terrarium floor, displaced the clutch with hind limbs, and showed antipredator behaviors toward a conspecific female and an intruding Roof Rat (Rattus rattus). During egg brooding, the female remained in contact with the clutch for about 98 of the time. In September 2008, two young hatched and shared the nesting site for six weeks with the female, which attended the nesting site for 87 of the time. Hatchlings repeatedly climbed over the female's body, lying on her for hours. The female walked out of the nesting site with a young on its back twice. These prolonged skin contacts between parent and offspring should be considered as the first certain case of young attendance in salamanders. This behavior may be related to increased survival of hatchlings during their first weeks of life, when young are particularly vulnerable to predation, skin infection, and dehydration. Copyright 2010 Society for the Study of Amphibians and Reptiles
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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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