1,720,957 research outputs found
Topside equatorial zonal ion velocities measured by C/NOFS during rising solar activity
Get PDFThe Ion Velocity Meter (IVM), a part of the Coupled Ion Neutral Dynamic
Investigation (CINDI) instrument package on the Communication/Navigation
Outage Forecast System (C/NOFS) spacecraft, has made over 5 yr of
in situ measurements of plasma temperatures, composition, densities, and
velocities in the 400–850 km altitude range of the equatorial ionosphere.
These measured ion velocities are then transformed into a coordinate system
with components parallel and perpendicular to the geomagnetic field allowing
us to examine the zonal (horizontal and perpendicular to the geomagnetic
field) component of plasma motion over the 2009–2012 interval. The general
pattern of local time variation of the equatorial zonal ion velocity is well
established as westward during the day and eastward during the night, with
the larger nighttime velocities leading to a net ionospheric superrotation.
Since the C/NOFS launch in April 2008, F10.7 cm radio fluxes have gradually
increased from around 70 sfu to levels in the 130–150 sfu range. The
comprehensive coverage of C/NOFS over the low-latitude ionosphere allows us
to examine variations of the topside zonal ion velocity over a wide level of
solar activity as well as the dependence of the zonal velocity on apex
altitude (magnetic latitude), longitude, and solar local time. It was found
that the zonal ion drifts show longitude dependence with the largest net
eastward values in the American sector. The pre-midnight zonal drifts show
definite solar activity (F10.7) dependence. The daytime drifts have a lower
dependence on F10.7. The apex altitude (magnetic latitude) variations
indicate a more westerly flow at higher altitudes. There is often a net
topside subrotation at low F10.7 levels, perhaps indicative of a suppressed
F region dynamo due to low field line-integrated conductivity and a low
F region altitude at solar minimum
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
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
Daytime zonal drifts in the ionospheric 150 km and <i>E</i> regions estimated using EAR observations
No full textMultibeam observations of the 150km echoes made using the Equatorial Atmosphere Radar (EAR), located at Kototabang, Indonesia, provide unique opportunity to study both vertical and zonal ExB plasma drifts in the equatorial ionosphere. In this paper, we focus on estimating daytime zonal drifts at the 150km (140-160km) and E (100-110km) regions using multibeam observations of 150km and E region echoes made using the EAR and study the daytime zonal drifts covering all seasons not studied before from Kototabang. Zonal drifts in the 150km and E regions are found to be westward and mostly below -80ms⁻¹ and -60ms⁻¹, respectively. While the zonal drifts in the 150km and E regions do not go hand in hand on a case-by-case basis, the seasonal mean drifts in the two height regions are found to be in good agreement with each other. Zonal drifts at the 150km region show seasonal variations with three maxima peaking around May, September, and January. The zonal drifts at the 150km region are found to be smaller than the F region drifts obtained from Coupled Ion Neutral Dynamics Investigation (CINDI) onboard Communication and Navigation Outage Forecasting System (C/NOFS) by about 25ms⁻¹ consistent with the height variations of F region zonal drifts observed by the Jicamarca radar. These results constitute the first comprehensive study of zonal drifts at the 150km and E regions from Kototabang, Indonesia, and the results are discussed in the light of current understanding on the low-latitude electrodynamics and coupling.JSPS KAKENHI Grant 15H05815; NARL. Grant Number: NARL‐ISPG.School of Natural Sciences and MathematicsWilliam B. Hanson Center for Space Science
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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