1,724,712 research outputs found
PTFO 8-8695: Two Stars, Two Signals, No Planet
No full text© 2020. The American Astronomical Society. All rights reserved.. PTFO 8-8695 (CVSO 30) is a star in the 7-10 million year old Orion OB1a cluster that shows brightness dips that resemble planetary transits. Although strong evidence against the planet hypothesis has been presented, the possibility remains debated in the literature. To obtain further clues, we inspected data from the NASA Transiting Exoplanet Survey Satellite (TESS) and the ESA Gaia mission. The Gaia data suggest that PTFO 8-8695 is a binary: the photometric data show it to be overluminous with respect to members of its kinematic group, and the astrometric data are inconsistent with a single star. The TESS light curve shows two different photometric periods. The variability is dominated by a sinusoidal signal with a period of 11.98 hr, presumably caused by stellar rotation. Also present is a 10.76 hr signal consisting of a not-quite sinusoid interrupted by hour-long dips, the type of signal previously interpreted as planetary transits. The phase of the dips is nearly 180 away from the phase of the originally reported dips. As noted previously, this makes them difficult to explain as planetary transits. Instead, we believe that PTFO 8-8695 is a pair of young and rapidly rotating M dwarfs, one of which shows the same "transient-dipper"behavior that has been seen in at least five other cases. The origin of these transient dips is still unknown but likely involves circumstellar material
Linked collectors and determiners for: Middlebury College Insect Collection: Bees (Anthophila).
No full textNatural history specimen data linked to collectors and determiners held within, "Middlebury College Insect Collection: Bees (Anthophila)". Claims or attributions were made on Bionomia by volunteer Scribes, <a href="http://bionomia.net/dataset/d2757de8-d83f-4c9a-8695-7fd1901ebdc2">https://bionomia.net/dataset/d2757de8-d83f-4c9a-8695-7fd1901ebdc2</a> using specimen data from the dataset aggregated by the Global Biodiversity Information Facility, <a href="https://gbif.org/dataset/d2757de8-d83f-4c9a-8695-7fd1901ebdc2">https://gbif.org/dataset/d2757de8-d83f-4c9a-8695-7fd1901ebdc2</a>. Formatted as a Frictionless Data package
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
Karoo research update: Progress, gaps and threats
Full text linkCITATION: Hoffman, M. T. et al. 2021. Karoo research update : progress, gaps and threats. South African Journal of Science, 117(1/2):8695, doi:10.17159/sajs.2021/8695.The original publication is available at https://sajs.co.zaIt has been more than three decades since the conclusion of the Karoo Biome Project (KBP).1 At its height in the
late 1980s, the KBP coordinated the efforts of nearly 100 research projects across a range of mainly ecological
and agricultural disciplines. In this brief update we examine the research that has occurred in the Nama-Karoo and
Succulent Karoo biomes since then and describe the relative contributions made by different disciplines to this
body of knowledge. We also highlight efforts to synthesise knowledge across the disciplinary divides. Finally, we
identify notable gaps in the research, especially considering the major land-use changes that are occurring across
the Karoo. We conclude that new questions should be asked and that significantly greater collaboration between
disciplines should be fostered in order to address the pressing challenges facing the Karoo more effectively. This
necessitates a far more coordinated response than has been the case to date. Institutional leadership and additional
funding will also be required to achieve this.https://sajs.co.za/article/view/8695Publisher's versio
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
Electron diffraction of tilted perovskites
Full text linkSimulations of electron diffraction patterns for each of the
known perovskite tilt systems have been performed. The
conditions for the appearance of superlattice reflections
arising from rotations of the octahedra are modified to take
into account the effects of different tilt systems for kinematical
diffraction. The use of selected-area electron diffraction as a
tool for perovskite structure determination is reviewed and
examples are included
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
- …
