1,721,140 research outputs found
Astrophysical interpretation of the medium scale clustering in the ultrahigh energy sky
No full textAbstractWe compare the clustering properties of the combined dataset of ultra-high energy cosmic rays events, reported by the AGASA, HiRes, Yakutsk and SUGAR Collaborations, with a catalogue of galaxies of the local universe (redshift z≲0.06). We find that the data reproduce particularly well the clustering properties of the nearby universe within z≲0.02. There is no statistically significant cross-correlation between data and structures, although intriguingly the nominal cross-correlation chance probability drops from O(50%) to O(10%) using the catalogue with a smaller horizon. Also, we discuss the impact on the robustness of the results of deflections in some galactic magnetic field models used in the literature. These results suggest a relevant role of magnetic fields (possibly extragalactic ones, too) and/or possibly some heavy nuclei fraction in the UHECRs. The importance of a confirmation of these hints (and of some of their implications) by Auger data is emphasized
Handling the uncertainties in the Galactic Dark Matter distribution for particle Dark Matter searches
No full textIn this work we characterize the distribution of Dark Matter (DM) in the Milky Way (MW), and its uncertainties, adopting the well known "Rotation Curve" method. We perform a full marginalization over the uncertainties of the Galactic Parameters and over the lack of knowledge on the morphology of the baryonic components of the Galaxy. The local DM density ρ 0 is constrained to the range 0.3- 0.8 GeV/cm 3 at the 2 σ level, and has a strong positive correlation to R 0 , the local distance from the Galactic Center. The not well-known value of R 0 is thus, at the moment, a major limitation in determining ρ 0 . Similarly, we find that the inner slope of the DM profile, γ, is very weakly constrained, showing no preference for a cored profile (γ0) or a cuspy one (γ[1.0,1.4]). Some combination of parameters can be, however, strongly constrained. For example the often used standard ρ 0 =0.3 GeV/cm 3 , R 0 =8.5 kpc is excluded at more than 4 σ. We release the full likelihood of our analysis in a tabular form over a multidimensional grid in the parameters characterizing the DM distribution, namely the scale radius R s , the scale density ρ s , the inner slope of the profile γ, and R 0 . The likelihood can be used to include the effect of the DM distribution uncertainty on the results of searches for an indirect DM signal in gamma-rays or neutrinos, from the Galactic Center (GC), or the Halo region surrounding it. As one example, we study the case of the GC excess in gamma rays. Further applications of our tabulated uncertainties in the DM distribution involve local DM searches, like direct detection and anti-matter observations, or global fits combining local and GC searches
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
Contextual Coding in Qualitative Research Involving Participants with Diverse Sociocultural Backgrounds
Full text linkUnderstanding participants' perspectives in qualitative research is contingent on unravelling the essential meaning of their speech. When data are collected in native language and translated into English language, the underlying sociocultural meaning of participants' speech can be missed. This paper discusses a new contextual coding approach and illustrates its application in research. The technique was used in a phenomenological study in Pakistan and a mixed methods study in Europe. Contextual coding entails a preliminary coding stage involving data reading in native language, choosing socially and culturally relevant words and phrases, and developing preliminary codes. The concluding coding stage focuses on creating a sociocultural query list, seeking answers through discussions among multilingual individuals, and finding a common language for code description. Contextual coding can enable researchers to understand sociocultural meaning of their data at an early stage, rather than waiting at the later stage of theme development to contextualize the findings
How deep is your involvement? Caregiver Contribution to self-care in heart failure: A content qualitative analysis with magnitude coding
No full textDispelling 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
- …
