1,721,016 research outputs found
A new record of Triassic dinosaur footprint from Monte Pisano (Northern Apennines, Italy): true or false?
No full textThe Upper Triassic continental deposits of Monte Pisano (Northern Apennines) preserve a high number of tetrapod tracks: some of them are among the most ancient italian records of dinosaurs. In this work we describe a putative, isolated ichnite (the “Agnano track”) from the top member of the Monte Serra Quartzites Formation consisting of a small-sized, tridactyl possible pes impression. Being concave and lying on the sole of a fine-grained arenaceous bed, this feature poses some serious difficulties in order to fully embrace its tetrapod-related origin, although concave hyporeliefs have been recently pointed out (but not investigated) by some authors. If the observed concave hyporelief is not an artefact, it could have been formed during the early phases of the diagenesis by differential compaction of the sandy layer immediately overlying a well-indurated undertrack. After having tentatively interpreted the “Agnano track” as a sort of “second generation” imprint, we emphasize its similarities with the Anomoepus-like group of vertebrate ichnites, thus proposing it could testify the passage of a basal ornitischian dinosaur
On a bone breccia near uliveto terme (Monte Pisano, Italy)
Full text linkOn a bone breccia near Uliveto Terme (Monte Pisano,Italy). The study of the macromammal remains of a bone breccia from the Uliveto quarry (Monte Pisano, Pisa) is here presented. The fossil material is scanty and very fragmented and consists mainly of Dama dama remains. The presence of Dama dama has been recognized also in another fossil site of the Monte Pisano (Grotta Cucigliana) referred to the late Aurelian
Da li je malooki mlat ikada nastanjivao Sredozemno more? Ponovno vrednovanje jedinog talijanskog nalaza vrste Sphyrina tudes (Valenciennes, 1822.)
Full text linkThree species of Sphyrna (S. lewini, S. mokarran and S. zygaena) are known to inhabit the present-day Mediterranean Sea, whereas uncertainties exist about the presence of S. tudes in the same basin. Indeed, the presence of this typically western Atlantic shark in the Mediterranean Sea is supported by as few as two historical specimens that were captured at Nice (southeastern France) and Leghorn (northern Tyrrhenian coast of central Italy). Here, we provide a redescription and an updated taxonomic identification of the Leghorn specimen of smalleye hammerhead, which is currently kept in the zoological collection of the Natural History Museum of the University of Pisa and is believed by some authors to represent a misidentified representative of S. lewini. Based on first-hand observations, we confirm the taxonomic identification of this specimen as belonging to S. tudes. Considering the ontogenetically young nature of both the Nice and the Leghorn specimens of S. tudes, parturition in the Mediterranean Sea is hypothesised, which in turn may evoke the occurrence of a population of smalleye hammerheads inhabiting this basin at least as recently as the early 19th century.Tri vrste roda Sphyrna (S. lewini, S. mokarran i S. zygaena) nastanjuju današnje Sredozemno more, no postoje nejasnoće oko prisutnosti vrste S. tudes u istom području. Prisutnost ovog tipično zapadno-atlantskog morskog psa u Sredozemnom moru podupiru samo dva povijesna primjerka uhvaćena kod Nice (jugoistočna Francuska) i Leghorna (sjeverna tirenska obala središnje Italije). U ovom radu iznosi se ponovni opis te ažurirana taksonomska identifikacija primjerka malookog mlata iz Leghorna, koji se trenutno čuva u zoološkoj zbirci Prirodoslovnog muzeja Sveučilišta u Pisi, a za kojeg neki autori vjeruju da predstavlja pogrešno identificiranog predstavnika vrste S. lewini. Na temelju izravnih promatranja, autori potvrđuju taksonomsku identifikaciju analiziranog primjerka kao pripadnika vrste S. tudes. S obzirom da su primjerci vrste S. tudes iz Nice i Leghorna mlade jedinke, pretpostavlja se da su okoćeni na području Sredozemog mora što može sugerirati prisutstvo populacije ove vrste na tom području barem do početka devetnaestog stoljeća
‘Hartite’ renamed branchite
Full text linkHistorical samples of branchite, described by the Tuscan naturalist Paolo Savi (1798–1871) at the end of the 1830s, were re-examined through single-crystal X-ray diffraction, showing their identity with hartite, C20H34, a hydrocarbon mineral described by Haidinger in 1841. The refined unit-cell parameters are a = 11.4116(7), b = 20.9688(12), c = 7.4100(4) Å, α = 93.947(2), β = 100.734(2), γ = 80.524(2)°, V = 1716.99(17) Å3 and Z = 4; space group P1. The crystal structure was solved and refined up to R1 = 0.0424 for 13512 reflections with Fo > 4σ(Fo) and 1265 refined parameters. As the name ‘branchite’ has priority over ‘hartite’, the reinstatement of the former name and the discreditation of the latter were approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA–CNMNC). Branchite is one of only eleven minerals formed by C and H listed in the official IMA List of Minerals. The type locality of branchite is the Botro di Lavajano, Monte Vaso, Chianni, Pisa, Tuscany, Italy. Neotype material is kept in the Natural History Museum of the Pisa University under catalogue number 14426
MUSEUM HISTORICAL COLLECTIONS TO BE REVISITED: REINSTATEMENT OF THE NAME “BRANCHITE” AFTER TWO CENTURIES
Full text linkDuring a study of the activity of Paolo Savi (1798 - 1871) as director of the Museum of Natural History of the University of Pisa, a note from 1839 on the description of a new organic mineral, called "branchite", was found. It was possible to examine the samples of "branchite" studied by Paolo Savi in the late 1830s, and a comprehensive investigation was undertaken by single crystal X-ray diffraction. Their isotypic relationship to hartite, C20H34, described in 1841, was demonstrated. The refined parameters of the unit cell were a = 11.4116(7), b = 20.9688(12), c = 7.4100(4) Å, α = 93.947(2), β = 100.734(2), γ = 80.524(2)°, V = 1716.99(17) Å3, Z = 4; space group P1. The crystal structure was resolved and refined to R1 = 0.0423 for 13512 reflections with Fo > 4σ(Fo) and 1266 refined parameters. Since branchite has priority over hartite, reinstatement of the former name and discrediting of the latter was approved by the IMA Commission on New Minerals, Nomenclature, and Classification. Branchite is one of the few mineral species formed by C and H only reported in the official IMA mineral list. Type locality of branchite is Botro di Lavajano, Monte Vaso, Chianni, Pisa, Italy; the neotype material is preserved in the Museum of Natural History of the University of Pisa under catalog number 14426
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
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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