1,720,957 research outputs found
Recommended from our members
Revealing the Magnetic Structure of the Solar Corona and Inner Heliosphere in the Era of Parker Solar Probe
Get PDFThe Sun’s atmosphere is a complex and dynamic magnetized plasma and extends all theway from its visible surface out into interplanetary space, carving out a bubble in the inter-
stellar medium which is called the heliosphere. All interactions between the Sun and life on
Earth are channelled through this medium. Of particular importance to making Sun-Earth
connections are the regions called the corona and the inner heliosphere. These two regimes
are strongly coupled together but their mutual boundary may be regarded as the location
where the dynamic pressure of the outflowing solar wind overcomes the magnetic pressure of
the Sun’s intrinsic field. By inner heliosphere, we focus on the portion of the Sun’s sphere of
influence which extends out to 1 au and therefore is most relevant to the Earth and humanity.Our most complete understanding of the corona and heliosphere comes from large scalephysical models which can fill in information about a plasma on a 3D grid. In 2018, Parker
Solar Probe (PSP) was launched into an orbit taking it closer to the Sun than any human-
made object in history. This has presented an opportunity to directly probe regions of the
heliosphere which had hitherto could only be accessed with global modelling. In this body
of work we use new data from PSP to improve our knowledge and understanding of this
global structure and further derive novel constraints on plasma models of the corona and
heliosphere.Specifically, we first introduce a framework for evaluating models of the coronal magneticfield, which sets how the solar wind emerges and shapes the inner heliosphere. In addition
to new PSP data which provides direct boundary conditions on the magnetic skeleton of the
corona, we show how it is important to make use of pre-existing observational capabilities
to constrain the sizes of coronal holes and the locations of high plasma density indicating
the topology of the coronal streamer belt. We illustrate how models must be constrained
at multiple boundaries to give an accurate representation and that focusing on individual
specific metrics can lead to different conclusions about optimum model parameters.Next, we use the full data set of the heliospheric magnetic field taken by Parker Solar Probein its first four years on orbit to directly measure the heliospheric magnetic field down to
0.13 au and compare directly to the large scale expectations of the Parker magnetic field.
We present evidence that at 0.13 au the heliospheric magnetic field remains latitudinally
isotropic, indicating the coronal field has already relaxed to this state within this radius.
We measure the open magnetic flux and confirm it is conserved between 1 au and PSP’s
closest approach to date. This conservation implies a deficit in open magnetic flux according
to coronal models with typically accepted model parameters. We also compare the mean
direction of the heliospheric magnetic field to the expectation of the Parker spiral model,
finding very good agreement which is tending to improve with closing distance from the sun
as the ratio of average field strength to random fluctuations increases.Third, we present a study in which we determine Parker Solar Probe’s magnetic connectivityback to specific coronal sources for its first solar encounter. This exercise allows determi-
nation of specific locations on the Sun which emit solar wind plasma later measured by
PSP, and therefore contextualises its measurements. This application of combining coronal
modelling and PSP data shows how making these connections is a vital building block for
understanding other peculiar plasma physics observed as PSP as it has explored new re-
gions of the inner heliosphere. Further, it allows disambiguation of spatial and temporal
phenomena.Finally, we present recent work using observations by Parker Solar Probe and other 1 auspacecraft to localise type III radio bursts, an impulsive solar ejection of electron beams,
from emission at the solar surface out into the inner heliosphere. These events have the
potential to act as passive tracers of coronal and heliospheric structure. We comment on
the future prospects of using this localisation to constrain magnetic connectivity and density
structure.We close with a summary of these results and the outlook for further improvement of ourunderstanding of the coupled corona and inner heliosphere ans PSP continues to approach
the Sun and as other advances in space based instrumentation are made, such as the gradual
escape of the Solar Orbiter to higher latitudes.The individual investigations, which are briefly introduced above, are united in highlightingseveral specific advances in our understanding of the Sun’s atmosphere facilitated by the ad-
dition of Parker Solar Probe to humanity’s suite of heliospheric instrumentation. Specifically,
we exemplify how multi-point, multi-spacecraft and multi-messenger observations at differ-
ent heliographic locations are vital in making progress in constraining our physical models;
using just one vantage point or one physical observable can lead to false conclusions about
model optimisation. We also observe an underlying thread of the surprising utility of the
very simplest model representations of the corona and heliosphere, for example a current-
free corona and essentially hydrodynamic heliosphere can accurately predict the magnetic
polarity structure, and even the velocity stream structure measured in situ by PSP. Lastly,
we verify that as one would expect from sending an instrument to never-before explored
regions of interplanetary space, new gaps in our understanding are identified. For example,
confirming that coronal models do not open enough magnetic flux to the inner heliosphere,
or showing at several points that while we make substantial progress exploring closer to the
Sun, a lack of far-side and high latitude remote sensing (most critically of the photospheric
magnetic field), remains a big limitation to accurately reproducing the physical structure of
the heliosphere
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
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
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
- …
