1,720,958 research outputs found
Constraining the modified symmetric teleparallel gravity using cosmological data
Full text linkCentre for Space Research, North-West University, Potchefstroom 2520, South AfricaThis paper examines the late-time accelerating Universe and the formation of large-scale
structures within the modified symmetric teleparallel gravity framework, specifically using the ()-
gravity model, in light of recent cosmological data. After reviewing the background history of the Universe,
and the linear cosmological perturbations, we consider the toy model () =
√
+ ( where represents
nonmetricity, and are model parameters) for further analysis. To evaluate the cosmological viability
of this model, we utilize 57 Observational Hubble Data (OHD) points, 1048 supernovae distance modulus
measurements (SNIa), their combined analysis (OHD+SNIa), 14 growth rate data points (f-data), and 30
redshift-space distortions (f8) datasets. Through a detailed statistical analysis, the comparison between
our model and ΛCDM has been conducted after we compute the best-fit values through the Markov Chain
Monte Carlo (MCMC) simulations. Based on the results, we obtain the Hubble parameter, 0 = 69.20+4.40
–2.10
and the amplitude of the matter power spectrum normalization 8 = 0.827+0.03
–0.01 . These values suggest that
our model holds significant promise in addressing the cosmological tensions
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
Constraints of Cosmic Expansion Using an MSF
Full text linkCentre for Space Research, North-West University, Potchefstroom 2520, South AfricaIn this paper, we propose a modified scale factor (MSF) that allows us to explore
the accelerating expansion of the universe without invoking the traditional dark-energy model, as
described in the Lambda cold dark matter (ΛCDM) model. Instead, the MSF model introduces
parameters that encapsulate the effects traditionally attributed to dark energy. To test the
viability of this MSF, we constrained the model using the observational Hubble parameter
(OHD), distance modulus measurements (SNIa), and their combined datasets (OHD + SNIa).
We implement a Monte Carlo Markov Chain (MCMC) simulation to find the best-fit values of
the model parameters. The MSF model produced best-fit values for the parameter p associated
with the power law of the matter-dominated era and β, the exponential parameter for the darkenergy-dominated era. For our MSF, these values are p = 0.28 and β = 0.52 when using SNIa
data, p = 0.63 and β = 0.30 for OHD data and p = 0.45 and β = 0.53 for a combination
of datasets (OHD + SNIa). The numerical results and plots of the deceleration parameter,
fractional energy density, Hubble parameter, and luminosity distance are presented which are
the key parameters for studying the accelerated expansion of the universe. We compare the
results of our model with that of the ΛCDM model and reconcile them with astronomical
observational data. Our results indicate that the MSF model shows promise, demonstrating
good compatibility with current astronomical observations and performing comparably to the
ΛCDM model across various datasets, particularly in predicting the accelerating expansion of
the universe, while providing a unified framework that incorporates the simultaneous influence
of matter and dark energy components
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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