1,721,214 research outputs found
Cosmology dependence of halo masses and concentrations in hydrodynamic simulations
Get PDFWe employ a set of Magneticum cosmological hydrodynamic simulations that span over 15 different cosmologies, and extract masses and concentrations of all well-resolved haloes between z = 0 and 1 for critical overdensities Δvir, Δ200c, Δ500c, Δ2500c and mean overdensity Δ200m. We provide the first mass-concentration (Mc) relation and sparsity relation (i.e. MΔ1 - MΔ2 mass conversion) of hydrodynamic simulations that is modelled by mass, redshift, and cosmological parameters ωm, ωb, σ8, h0 as a tool for observational studies. We also quantify the impact that the Mc relation scatter and the assumption of Navarro-Frank-White (NFW) density profiles have on the uncertainty of the sparsity relation. We find that converting masses with the aid of an Mc relation carries an additional fractional scatter (4 percent;) originated from deviations from the assumed NFW density profile. For this reason, we provide a direct mass-mass conversion relation fit that depends on redshift and cosmological parameters. We release the package hydro_mc, a python tool that perform all kind of conversions presented in this paper
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
Cosmological constraints from the abundance, weak lensing, and clustering of galaxy clusters: Application to the SDSS
Get PDFAims. The clustering of galaxy clusters is a powerful cosmological tool. When it is combined with other cosmological observables, it can help to resolve parameter degeneracies and improve constraints, especially on Ωm and Ï8. We aim to demonstrate its potential in constraining cosmological parameters and scaling relations when combined with cluster counts and weak-lensing mass information. As a case study, we use the redMaPPer cluster catalog derived from the Sloan Digital Sky Survey (SDSS). Methods. We extended a previous analysis of the number counts and weak-lensing signal by the two-point correlation function. We derived cosmological and scaling relation posteriors for all possible combinations of the three observables to assess their constraining power, parameter degeneracies, and possible internal tensions. Results. We find no evidence for tensions between the three data sets we analyzed. We demonstrate that the constraining power of the sample can be greatly improved by including the clustering statistics because this can break the Ωmâ â â Ï8 degeneracy that is characteristic of cluster abundance studies. In particular, for a flat Î CDM model with massive neutrinos, we obtain Ωmâ =â 0.28â ±â 0.03 and Ï 8â =â 0.82â ±â 0.05, which is an improvement of 33% and 50% compared to the posteriors derived by combining cluster abundance and weak-lensing analyses. Our results are consistent with cosmological posteriors from other cluster surveys, and also with Planck results for the cosmic microwave background (CMB) and DES-Y3 galaxy clustering and weak-lensing analysis
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
SZE observables, pressure profiles and centre offsets in Magneticum simulation galaxy clusters
No full textWe present a detailed study of the galaxy cluster thermal Sunyaev-Zel'dovich effect (SZE) signal Y and pressure profiles using Magneticum Pathfinder hydrodynamical simulations. With a sample of 50 000 galaxy clusters (M500c > 1.4 × 1014 M☉) out to z = 2, we find significant variations in the shape of the pressure profile with mass and redshift and present a new generalized NFW (Navarro-Frenk-White) model that follows these trends. We show that the thermal pressure at R500c accounts for only 80 per cent of the pressure required to maintain hydrostatic equilibrium, and therefore even idealized hydrostatic mass estimates would be biased at the 20 per cent level. We compare the cluster SZE signal extracted from a sphere with different virial-like radii, a virial cylinder within a narrow redshift slice and the full light-cone, confirming small scatter (σln Y ≃ 0.087) in the sphere and showing that structure immediately surrounding clusters increases the scatter and strengthens non-self-similar redshift evolution in the cylinder. Uncorrelated large-scale structure along the line of sight leads to an increase in the SZE signal and scatter that is more pronounced for low-mass clusters, resulting in non-self-similar trends in both mass and redshift and a mass-dependent scatter, that is, ∼0.16 at low masses. The scatter distribution is consistent with lognormal in all cases. We present a model of the offsets between the centre of the gravitational potential and the SZE centre that follows the variations with cluster mass and redshift
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