1,720,993 research outputs found
Testing variation in body size in populations of Bos primigenius from southern and central Italy
No full textErratum: MERELLA, M., COLLARETA, A., CASATI, S., DI CENCIO, A. & BIANUCCI, G. (2021): An unexpected deadly meeting: Deep- water (hexanchid) shark bite marks on a sirenian skeleton from Pliocene shoreface deposits of Tuscany (Italy). - Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen, 301 (3): 295-305. doi: 10.1127/njgpa/2021/1012
No full textAbstract not availabl
First fossils of the extant blacktip shark carcharhinus limbatus from europe and the mediterranean basin
No full textHere we report on two fossil teeth attributed to the blacktip shark Carcharhinus limbatus (Elasmobranchii: Carcharhiniformes: Carcharhinidae) from lower Pliocene (ca. 5.1–4.5 Ma) marine deposits of Tuscany (central Italy). A survey of the palaeoichthyological literature and online resources reveals that fossils of C. limbatus have been reported from Neogene and Quaternary deposits of the Americas and Indo-Pacific Asia. Therefore, the Tuscan specimens described herein represent the first occurrence of C. limbatus as a fossil from both Europe and the Mediterranean Basin. Our finds suggest that the blacktip shark reached a circumglobal distribution in warm waters (including the then warmer-than-today Mediterranean Sea) not later than the Pliocene; at the same time, they demonstrate that the continued study of the relatively well-investigated Neogene elasmobranch faunas of Italy can still result in significant novelties. Further investigations on other shark tooth assemblages from shallow-marine, warm-water, nearshore deposits are likely to reveal new occurrences of C. limbatus in the Pliocene of the Mediterranean Sea and elsewhere (e.g., along the palaeontologically under-explored Atlantic and Pacific coasts of Africa)
Did titanic stingrays wander the Pliocene Mediterranean Sea? Some notes on a giant-sized myliobatoid stinger from the Piacenzian of Italy
No full textA fossil caudal spine of a stingray (Elasmobranchii: Batomorphii: Myliobatoidei) is here reported from upper Pliocene (Piacenzian) shallow-marine deposits exposed at the La Serra locality of Tuscany (central Italy). In spite of being incomplete, this specimen displays an amazing maximum preserved anteroposterior length of 420 mm, which to our knowledge makes it the longest stingray stinger ever reported from both the fossil and the Recent records. Tentatively referred to the family Dasyatidae, the herein described fossil appears to be more than twice as long as the longest caudal spines reported from any living myliobatoid species of the Mediterranean Sea. Therefore, it represents a stingray taxon that is no longer featured in the present-day Mediterranean ray assemblage, and as such, it expands our knowledge on the Pliocene biodiversity of the Mediterranean Sea. Given that the living species Bathytoshia brevicaudata (the smooth stingray) and Urogymnus polylepis (the giant freshwater stingray), while displaying the greatest values of total stinger length (up to c. 375 mm in the latter) among extant myliobatoids, are also known as the largest living species of stingrays besides Mobulidae, it seems much reasonable to hypothesise that the caudal spine from La Serra belonged to a very large-sized stingray individual which would have been larger than (or at least comparable in dimensions to) the largest members of the titan-sized B. brevicaudata and U. polylepis
Canis (Mammalia, Canidae) from the Holocene deposits of Grotta La Sassa (Latina, Central Italy)
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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
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