1,720,971 research outputs found
Constraining axion and compact dark matter with interstellar medium heating
Get PDFCold interstellar gas systems have been used to constrain dark matter (DM)
models by the condition that the heating rate from DM must be lower than the
astrophysical cooling rate of the gas. Following the methodology of Wadekar and
Farrar (2021), we use the interstellar medium of a gas-rich dwarf galaxy, Leo
T, and a Milky Way-environment gas cloud, G33.4-8.0 to constrain DM. Leo T is a
particularly strong system as its gas can have the lowest cooling rate among
all the objects in the late Universe (owing to the low volume density and
metallicity of the gas). Milky Way clouds, in some cases, provide complementary
limits as the DM-gas relative velocity in them is much larger than that in Leo
T. We derive constraints on the following scenarios in which DM can heat the
gas: interaction of axions with hydrogen atoms or free electrons in the
gas, deceleration of relic magnetically charged DM in gas plasma,
dynamical friction from compact DM, hard sphere scattering of
composite DM with gas. Our limits are complementary to DM direct detection
searches. Detection of more gas-rich low-mass dwarfs like Leo T from upcoming
21cm and optical surveys can improve our bounds.Comment: 10+6 pages, 8 figures. Version appearing in PRD. Added more realistic
calculation of escape velocity in Leo
Strong constraints on decay and annihilation of dark matter from heating of gas-rich dwarf galaxies
Get PDFGas-rich dwarf galaxies located outside the virial radius of their host are
relatively pristine systems and have ultra-low gas cooling rates. This makes
them very sensitive to heat injection by annihilation or decay of dark matter
(DM). Such dwarfs are particularly sensitive to DM producing e with
energies 1100 MeV or photons with energies 13.6 eV keV, because these
products can be efficiently thermalized in the neutral hydrogen gas of the
dwarfs. Following the methodology of Wadekar and Farrar (2021), we require the
rate of heat injection by DM to not exceed the ultra-low radiative cooling rate
of gas in the Leo T dwarf galaxy. This gives model-independent bounds on
the decay lifetime of DM to (photons) which are stronger than all the
previous literature for 110 MeV
( keV), annihilation of DM to
comparable to constraints from CMB and X/-ray surveys. We also
translate our bounds for the case of the following DM models: axion-like
particles (ALPs), sterile neutrinos, excited DM states, higgs portal scalars
and dark baryons. Observations of gas-rich low-mass dwarfs from upcoming 21cm
and optical surveys can therefore be powerful probes of a multitude of models
of DM.Comment: 11+4 pages, 7 figures. Version appearing in PRD. Added more
conservative estimates of DM limits and a discussion of senstivity of the
limits to DM halo model. The code associated with this paper is available at
https://github.com/JayWadekar/Gas_rich_dwarf
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
Auxiliary data release for "Fast marginalization algorithm for optimizing gravitational wave detection, parameter estimation and sky localization"
No full text<p>This release contains parameter estimation runs on synthetic injections, described in https://arxiv.org/abs/2404.02435 .</p>
<p>Important note: The posterior samples provided are weighted, the weights are stored in a column named 'weights' . </p>
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
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