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The noble gas concentrations of the Martian meteorites GRV 99027 and paired NWA 7906/NWA 7907
Full text linkHere we present the isotopic concentrations of He, Ne, Ar, Kr, and Xe for the
three Martian meteorites, namely Grove Mountains 99027 (GRV 99027), Northwest Africa
7906 (NWA 7906), and Northwest Africa 7907 (NWA 7907). The cosmic ray exposure
(CRE) age for GRV 99027 of 5.7 ± 0.4 Ma (1δ) is consistent with CRE ages for other
poikilitic basaltic shergottites and suggests that all were ejected in a single event ~5.6 Ma
ago. After correcting for an estimated variable sodium concentration, the CRE ages for
NWA 7906 and NWA 7907 of 5.4 ± 0.4 and 4.9 ± 0.4 Ma (1r), respectively, are in good
agreement with the CRE age of ~5 Ma favored by Cartwright et al. (2014) for NWA 7034.
The data, therefore, support the conclusion that all three basaltic regolith breccias are
paired. The ⁴⁰Ar gas retention age for NWA 7907 of ~1.3 Ga is in accord with Cartwright
et al. (2014). For NWA 7906, we were unable to determine a ⁴⁰Ar gas retention age. The
⁴He gas retention ages for NWA 7906 and 7907 are in the range of 200 Ma and are much
shorter than the ⁴⁰Ar gas retention age of NWA 7907, indicating that about 86–88% of the
radiogenic ⁴He has been lost. The Kr and Xe isotopic concentrations in GRV 99027 are
composed almost exclusively of Martian interior (MI) gases, while for NWA 7906 and
NWA 7907, they indicate gases from the MI, elementally fractionated air, and possibly
Martian atmosphere
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Willamette River Floodplain 100 Meter Slices Framework: WR 06 Map (Slices 7907 to 9309, River Miles 56 to 71)
No full textSlices 7907 to 9309, River Miles 56 to 7
Ringtestsamarbeid for kjemiske vannanalyser. Ringtest 7907: pH, konduktivitet, fluorid og sulfat
No full textSom ledd i et løpende ringtestsamarbeid for kjemiske vannanalyser ble ringtest 7907 arrangert i februar-mars 1979 med 124 deltagende laboratorier. Ringtesten omfattet bestemmelse av pH, konduktivitet, sulfat og fluorid, og ble gjennomført etter Youdens metode.Statens forurensningstilsy
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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