1,721,113 research outputs found
Early Eocene to early Miocene radiolarian biostratigraphy for the low-latitude Pacific Ocean
No full textA total of 226 early Eocene to early Miocene radiolarian datum events are identified and correlated with the geochronologic time scale at SitesU1331, U1332, and U1333 in the equatorial Pacific Ocean. Seven new radiolarian subzones are proposed for the low-latitude Oligocene: Eucyrtidium diaphanes Interval Subzone (RP22b); Calocycletta (Calocycletta) robusta Interval Subzone (RP22a); Lychnocanoma apodora Interval Subzone (RP21b); Theocyrtis annosa Interval Subzone (RP21a); Eucyrtidium plesiodiaphanes Interval Subzone (RP20c); Dorcadospyris pseudopapilio Interval Subzone (RP20b); Lithocyclia angusta Interval Subzone (RP20a). These subzones significantly improve the biostratigraphic resolutionwithin theOligocene (an average of one subzone per 1.6 million years [my]).Our study corroborates previous studies,which inferred that primary Oligocene datumswere synchronous in the low-latitude Pacific. Four Eocene zones, Cryptocarpium ornatum (RP19), Calocyclas bandyca (RP18), Phormocyrtis striata striata (RP9), and Buryella clinata (RP8) are emended. Two new species/subspecies, Lychnocanoma klausi and Theocorys anaclasta clasta, are describe
Unprecedented Mechanism Employed by the Salmonella enterica EutT ATP: Co(I)rrinoid Adenosyltransferase Precludes Adenosylation of Incomplete Co(II)rrinoids
No full textThree distinct families of ATP: corrinoid adenosyltransferases (ACATs) exist that are capable of converting vitamin B-12 derivatives into coenzyme B-12 by catalyzing the thermodynamically challenging reduction of Co(II)rrinoids to form "supernucleophilic" Co-I intermediates. While the structures and mechanisms of two of the ACAT families have been studied extensively, little is known about the EutT enzymes beyond the fact that they exhibit a unique requirement for a divalent metal cofactor for enzymatic activity. In this study we have obtained compelling evidence that EutT converts cob(II) alamin into an effectively four-coordinate Co-II species so as to facilitate Co-II -> Co-I reduction. Intriguingly, EutT fails to promote axial ligand dissociation from the substrate analogue cob(II) inamide, a natural precursor of cob(II) alamin. This unique substrate specificity of EutT has important physiological implications
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
(Figure 1) Radiolarian range chart of ODP Site 138-844, part I
No full textDEPTH, sediment is given in mbsf. Relative abundance of individual species: R = rare (200 specimens). A- signifies that a species was looked for and not found, small case letters = specimens found that are thought to be reworked, ? = a dubious identification
(Figure 5) Radiolarian range chart of ODP Site 138-848, part I
No full textDEPTH, sediment is given in mbsf. Relative abundance of individual species: R = rare (200 specimens). A- signifies that a species was looked for and not found, small case letters = specimens found that are thought to be reworked, ? = a dubious identification
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe 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
(Figure 1) Radiolarian range chart of ODP Site 138-844, part II
No full textDEPTH, sediment is given in mbsf. Relative abundance of individual species: R = rare (200 specimens). A- signifies that a species was looked for and not found, small case letters = specimens found that are thought to be reworked, ? = a dubious identification
(Figure 2) Radiolarian range chart of ODP Site 138-845A, part III
No full textDEPTH, sediment is given in mbsf. Relative abundance of individual species: R = rare (200 specimens). A- signifies that a species was looked for and not found, small case letters = specimens found that are thought to be reworked, ? = a dubious identification
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