1,721,459 research outputs found
Bifurcation Analysis of Sequence of Magnetic Island Equilibria and Spontaneous Generation of Zonal Flow
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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
Are ants not only 'social insects', but also 'nomic insects'? In search of clues of normativity in the ant world
No full textRecently, various philosophers and ethologists have argued or hypothesised that, in addition to humans, there are also non-human animals that are capable of following rules and implementing normative behaviours. The investigation of animal normativity until now, however, has been almost exclusively focused on mammals and, in particular, non-human primates and cetaceans. In contrast, this work aims to extend this research to the world of invertebrates and, more specifically, to the world of eusocial insects. For the purpose of investigating whether there are clues of normativity in the world of eusocial insects, we will inquire into the question of whether certain behaviours of ants can be considered normatively conditioned behaviours
Nonlinear processes in Hamiltonian reconnection
No full textThe generation of small spatial scales and their interplay with large scale coherent structures is one of the outstanding phenomena of plasma physics and fluid mechanics. In high temperature space and laboratory plasmas dissipative effects become important at length scales that are much smaller than those where microscopic dynamical effects, related e.g., to electron inertia, come into play. Here we discuss the role of this dissipationless small scale dynamics on the nonlinear evolution of collisionless magnetic reconnection within the framework of the so called "two-field" and "four-field models". (C) 2008 Elsevier B.V. All rights reserved
Occurrence of honey bee (Apis mellifera) pathogens in ants (Hymenoptera: Formicidae): a systematic review
No full textShedding (Gamma) Light on the Cosmic Ray Population in the Galactic Center Region
No full textThe nature of the very-high-energy gamma-ray diffuse emission measured by H.E.S.S. in the Galactic Center (GC) region is still matter of debate. Two main scenarios have been proposed to interpret H.E.S.S. results, where the emission arises from a cosmic-ray (CR) population, which is either originated from a local PeVatron or is the “tip of the iceberg” of an inhomogeneous Galactic CR sea. The latter scenario is motivated by recent analysis of the Galactic diffuse emission measured by Fermi-LAT as well as from Milagro and recent HAWC results. In this contribution we compare these interpretations against H.E.S.S. data in combination with updated Fermi-LAT data, which allow to extend the measured spectrum down to few GeVs. Besides the Central Molecular Zone and the Sgr B gas complex - for which we find a good agreement with data for both scenarios - here we consider, for the first time in this framework, the emission of J1741-302, under the hypothesis that is due to the interaction of CRs with a massive cloud lying on the Galactic plane at about 260 pc from the GC. We find the CR sea scenario reproduces the spectrum of J1741-302 (+ Fermi-LAT) remarkably well, while the GC PeVatron - due to the 1/r profile of the CR density profile - falls short. Therefore, our result strongly favours the CR sea interpretation of the measured γ-ray diffuse emission from the innermost region of the Galaxy
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