1,721,033 research outputs found
Table ronde et discussion commune de David Mattingly "Between Sahara and Sea. Africa in the Roman Empire", 30 Janvier 2024, en ligne (RomanIslam-Center Hambourg)
No full textÉvénement en ligne, Mardi, 30 Janvier 2024, 16h (européenne) Pour s'enregistrer sur zoom, contactez [email protected]. Discutants: Touatia Amraoui, Stefan Ardeleanu, Samir Ben Tahar, David Mattingly, Sambia Panzram, David Stone Plus d'informations sur: https://www.romanislam.uni-hamburg.de/events-news/round-tables.html
TeV astrophysics constraints on Planck scale Lorentz violation
No full textWe analyze observational constraints from TeV astrophysics on Lorentz violating nonlinear dispersion for photons and electrons without assuming any a priori equality between the photon and electron parameters. The constraints arise from thresholds for vacuum Cerenkov radiation, photon decay and photo-production of electron-positron pairs. We show that the parameter plane for cubic momentum terms in the dispersion relations is constrained to an order unity region in Planck units. We find that the threshold configuration can occur with an asymmetric distribution of momentum for pair creation, and with a hard photon for vacuum Cerenkov radiation
Astrophysical bounds on Planck suppressed Lorentz violation
No full textThis article reviews many of the observational constraints on Lorentz symmetry violation (LV). We first describe the GZK cutoff and other phenomena that are sensitive to LV. After a brief historical sketch of research on LV, we discuss the effective field theory description of LV and related questions of principle, technical results, and observational constraints. We focus on constraints from high energy astrophysics on mass dimension five operators that contribute to IV electron and photon dispersion relations at order E/M-Planck. We also briefly discuss constraints on renormalizable operators, and review the current and future constraints on IV at order (E/M-Plank)(2)
sj-docx-1-hol-10.1177_09596836231211879 – Supplemental material for Origins and evolution of oasis agriculture in the Sahara: Evidence from morphometric analyses of archaeological date palm seeds
No full textSupplemental material, sj-docx-1-hol-10.1177_09596836231211879 for Origins and evolution of oasis agriculture in the Sahara: Evidence from morphometric analyses of archaeological date palm seeds by Thomas Kaczmarek, Marijke Van der Veen, Sarah Ivorra, David Mattingly, Jean-Frédéric Terral and Muriel Gros-Balthazard in The Holocene</p
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
Garamantian Oasis settlements in Fazzan
No full textThe article presents a long and detailed analysis of the settlements excavated and surveyed in the Fazzan region, Libyan Sahara, in Garamantian times. The Garamantian period is a crucial phase in the history of the Sahara, as the earliest urbanisation and state formation process develop
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
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