1,721,019 research outputs found
Quantitative foraminiferal and palynomorph biostratigraphy of the Paleogene in the southwestern Barents Sea
No full textThe stratigraphic distribution of both foraminifera and dinoflagellate cysts is recorded from the
Paleocene to Eocene Torsk Formation in 12 petroleum exploration wells drilled in the southwestern
Barents Sea. The foraminiferal assemblages are wholly agglutinated, and are referred to outer shelf to
middle bathyal environments. A quantitative analysis of biostratigraphic events, mainly last
occurrences (first downhole occurrences), is performed by means of the Ranking and Scaling (RASC)
program. This procedure combined with conventional stratigraphic treatment has enabled us to
establish the most likely order of microfossil events, and to propose a new quantitative zonal scheme
for the southwestern Barents Sea.
In the studied wells the following six zones and subzones are distinguished (in ascending order):
BSP 1, Psmmosphaera fusca – Hyperammina rugosa, late early to early late Paleocene; BSP 2,
Spiroplectammina spectabilis early late Paleocene; BSP 3A, Reticulophragmium pauperum, middle late
Paleocene; BSP 3B, Haplophragmoides aff. eggeri, latest Paleocene; BSP 4, Spiroplectammina navarroana,
earliest Eocene; BSP 5, Reticulophragmium amplectens, early to middle Eocene. Owing to the
occurrence of cosmopolitan deep-water agglutinated foraminifera, the new zonal scheme compares
well with previous zonations developed for the Paleogene of the mid-Norwegian shelf, the North Sea
and Labrador Shelf
The Paleogene Period
Full text linkABSTRACT All Paleocene stages (i.e., Danian, Selandian and Thanetian) have formally ratified definitions, and so have the Ypresian and Lutetian Stages in the Eocene, and the Rupelian Stage in the Oligocene. The Bartonian, Priabonian and Chattian Stages are not yet formally defined. After the global catastrophe and biotic crisis at the CretaceousePaleogene boundary, stratigraphically important marine microfossils started new evolutionary trends, and on land the now flourishing mammals offer a potential for stratigraphic zonation. During the Paleogene the global climate, being warm until the late Eocene, shows a significant cooling trend culminating in a major cooling event in the beginning of the Oligocene, preparing the conditions for modern life and climate. Orbitally tuned cyclic sedimentation series, calibrated to the geomagnetic polarity and biostratigraphic scales, have considerably improved the resolution of the Paleogene time scale. The Paleogene Period - ResearchGate. Available from: http://www.researchgate.net/publication/236611297_The_Paleogene_Period [accessed Mar 23, 2015]
The Neogene Period
No full textAn Astronomically Tuned Neogene Time Scale (ATNTS2012) is presented, as an update of ATNTS2004 in GTS2004. The new scale is not fundamentally different from its predecessor and the numerical ages are identical or almost so. Astronomical tuning has in principle the potential of generating a stable Neogene time scale as a function of the accuracy of the La2004 astronomical solution used for both scales. Minor problems remain in the tuning of the Lower Miocene. In GTS2012 we will summarize what has been modified or added since the publication of ATNTS2004 for incorporation in its successor, ATNTS2012. Mammal biostratigraphy and its chronology are elaborated, and the regional Neogene stages of the Paratethys and New Zealand are briefy discussed. To keep changes to ATNTS2004 transparent we maintain its subdivision into headings as much as possible
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
Mediterranean pliocene globorotalia : a biometrical approach
No full textGloborotalia assemblages are studied from Pliocene deposits in Crete
(Greece), Italy, the Gulf of Mexico region, and New Zealand. In each
assemblage counts and measurements were performed on 10 test characters.
The taxonomy is based on (1) biconvex or planoconvex shape, (2) "growth"
patterns of size ratios, (3) frequency distributions of discrete characters on
the test. Attention is given to the treatment of such quantitative data.
The assemblages have been collected in five groups named after typologically
defined species: (1) margaritae group, (2) crassaformis group, (3) puncticulata
group, (4) bononiensis group, and (5) inflata group. Each group is
illustrated by means of a number of scanning electron microscope photographs;
some attention is drawn to wall structures.
The puncticulata, bononiensis, and inflata groups occur in stratigraphic
order; the ranges do not overlap. In Crete an incidental morphological
transition was observed between the bononiensis group and the inflata
group.
In the Mediterranean the association of the margaritae group and the
puncticulata group is restricted to the Lower Pliocene (Tabianian). The
puncticulata group ranges slightly higher in the stratigraphic column than
does the margaritae group. The upper part of the range of the puncticulata
group, the total range of the bononiensis group, and the lower part of the
range of the inflata group are indicative of the Middle-Upper Pliocene
(Piacenzian). The crassaformis group occurs throughout the Pliocene.
In the Gulf of Mexico region the puncticulata and bononiensis groups
were not observed. The occurrence of the margaritae group and the beginning
of the inflata group may be used for stratigraphic correlations.
The crassaformis group displays trends, but it may be doubted if the
zigzag path of this group is stratigraphically useful, except perhaps on a local
scale. Assemblages of a New Zealand G. crassaformis bioseries show no
resemblance to our crassaformis group
The age of beds in the Lettenkohle facies in South-East France (a palynological approach)
No full textThe palynological assemblage from Lettenkohle deposits near Ucel (Ardèche, France) can be matched with those from Karnian deposits in the Austrian Alps. The occurrence of Camerosporites secatus suggests a correlation with the Middle Upper Triassic (Karnian) of the North Sea Basin. The Ucel assemblage shows striking differences to a palynological assemblage obtained from Lettenkohle deposits near Crussol (50 km North-East of Ucel)
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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