1,720,957 research outputs found
Monte Carlo simulations of a near-solar orbit neutrino detector
Full text linkThesis (M.S.)-- Wichita State University, College of Liberal Arts and Sciences, Dept. of Mathematics, Statistics, and PhysicsNeutrinos—weakly interacting subatomic particles often resultant of nuclear
processes, including hydrogen fusion—are the only direct insight into the core of the Sun.
Previously constructed neutrino detection experiments have successfully detected
solar-origin neutrinos, proving hydrogen fusion to be the Sun’s energy production
mechanism; however, these experiments’ large size and Earth-based location limit their
capabilities. A solar neutrino detection satellite orbiting the sun with a close approach
distance of 7 to 3 solar radii could revolutionize solar interior studies. At such proximity,
the neutrino flux increases by several orders of magnitude allowing for a much smaller
detector design than Earth-based devices. An off-ecliptic orbital location also allows for
fusion core geometry studies. To pursue these improvements, a scintillation detector using
gallium-doped liquid scintillator and veto array methods has been devised. Interactions
between neutrinos and gallium nuclei can result in a sequentially released electron and
gamma-ray/X-ray, giving distinct double-pulse signals in the detector. The veto array is a
secondary detection assembly to filter external-source charged particles. Presented here are
the methods and results from Monte Carlo simulations of particle events visible to the
detector. This code incorporates background event rates obtained from Geant4 simulations
of the detector assembly, and neutrino interaction rates based on scaling of similar,
Earth-based experiments’ performance to the detector’s parameters. The code output is
examined to find the number of true double-pulse signals versus those of false signals.
Establishing experiment parameters necessary for a false event detection rate less than 20%
is a primary goal of these simulations
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
From the Moon to Charon: Mission-Inspired Laboratory Investigations Into Space Weathering and Polar Reddening
Full text linkRecent spacecraft observations have revealed small Solar System bodies such as our Moon and Pluto’s moon Charon to present surface albedos shaped by their environments. The lunar surface is subject to space weathering—solar wind irradiation and micrometeoroid bombardment—which affects surface far-ultraviolet (FUV) reflectance observed by the Lunar Reconnaissance Orbiter (LRO) spacecraft’s Lyman Alpha Mapping Project (LAMP) instrument. Methane trapped at Charon’s winter poles is exposed to interplanetary medium Lyman-α photons, generating mostly ethane which may be further altered to produce the red-hued landscape observed in New Horizons images. Understanding these planetary surfaces through interpretation of spacecraft data often requires robust laboratory-based experiments. Presented in this dissertation are three such experimental thrusts applied to the Moon and Charon. The first compares FUV reflectance spectra of lunar simulants JSC-1A and LMS-1 and Apollo lunar soil sample 10084. Differences in the FUV reflectance of these soils point to space weathering as the primary contributor to backscattering behavior and high titanium-bearing mineral content possibly correlating to decreased brightness at shorter wavelengths. The second study extends these FUV measurements to Apollo soils 68501 and 71061. Space weathering is found to likely influence the scattering anisotropy of these soils; however, 10084 and 68501 show nearly identical reflectance, implying that FUV spectra are unable to strongly distinguish between highly space weathered mare and highland soils. The final investigation of this dissertation presents UV-Visible-NIR reflectance spectroscopy of ethane ice relevant to Charon, showing a “thermal reddening” process which potentially contributes—along with solar-wind processing of the ethane—to Charon’s colorful polar landscape.Physics and Astronom
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
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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