1,720,981 research outputs found
The contribution of the De Filippi expedition (1913-1914) to the geological knowledge of the Aksai Chin region (western Himalaya)
No full textBetween the years 1913 to 1914 the De Filippi Expedition, led by the Italian explorer and
mountaineer Filippo De Filippi (1869–1938), traversed the Himalayan Range from Kashmir
to Baltistan and Xinjiang. Exploring mostly unknown territories, traveling more than 2000
kilometers, and equipped with advanced instruments for geodetic and meteorological
measurements, the expedition members surveyed, mapped and collected rocks and fossils
including from the remote Aksai Chin region. After almost two years, the expedition
returned to Italy, however, publication of the findings was delayed due to the outbreak of
the First World War. The fossil material and syntheses of the geology and stratigraphy of
the area represented unique documents on this sector of Western Tibet, with the Cretaceous
Period being documented by the expedition for the first time in the whole Trans-Himalayan
Range. The Aksai Chin region remains poorly explored even today, and the De Filippi
collection which is housed in the Natural History Museum of the University of Florence now
represents one of the few records available for reconstructing the stratigraphy of the area. It
constitutes a valuable resource regarding the history of the scientific exploration and
understanding of the geology and paleontology of the region, providing a unique window
into a very remote and fascinating part of the world
Mapping solar system chaos with the Geological Orrery
Full text linkThe Geological Orrery is a network of geological records of orbitally paced climate designed to address the inherent limitations of solutions for planetary orbits beyond 60 million years ago due to the chaotic nature of Solar System motion. We use results from two scientific coring experiments in Early Mesozoic continental strata: the Newark Basin Coring Project and the Colorado Plateau Coring Project. We precisely and accurately resolve the secular fundamental frequencies of precession of perihelion of the inner planets and Jupiter for the Late Triassic and Early Jurassic epochs (223–199 million years ago) using the lacustrine record of orbital pacing tuned only to one frequency (1/405,000 years) as a geological interferometer. Ex- cepting Jupiter’s, these frequencies differ significantly from present values as determined using three independent techniques yielding practically the same results. Estimates for the precession of perihe- lion of the inner planets are robust, reflecting a zircon U–Pb-based age model and internal checks based on the overdetermined origins of the geologically measured frequencies. Furthermore, although not indicative of a correct solution, one numerical solution closely matches the Geological Orrery, with a very low probability of being due to chance. To determine the secular fundamental frequencies of the precession of the nodes of the planets and the important secular resonances with the precession of perihelion, a contemporaneous high-latitude geological archive recording obliquity pacing of climate is needed. These results form a proof of concept of the Geological Orrery and lay out an empirical framework to map the chaotic evo- lution of the Solar System
A Different Opinion on the Geological Age of the Longzhaogou and Jixi Groups of Eastern Heilongjiang, China1
No full textSome Lower Cretaceous nonmarine bivalves from fluvio-lacustrine deposits bearing dinosaur fossils in Mongolia and Northeast China
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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
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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