10,928 research outputs found

    Undefining Man: A Case for Symbolic Animal Communication via Refutation of Kenneth Burke\u27s Definition of Man

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    There have been tendencies in various fields to use communication as a way of differentiating humans and other species. Even when individuals are confronted with empirical evidence to the contrary, many still hold onto the notion that humans are in a communicative position clearly divergent in all ways from animals. This thesis will utilize Kenneth Burke\u27s Definition of Man as a launching point to support a claim that animals utilize their conscious cognitive abilities to communicate symbolically

    A system of mobile agents to model social networks

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    We propose a model of mobile agents to construct social networks, based on a system of moving particles by keeping track of the collisions during their permanence in the system. We reproduce not only the degree distribution, clustering coefficient and shortest path length of a large data base of empirical friendship networks recently collected, but also some features related with their community structure. The model is completely characterized by the collision rate and above a critical collision rate we find the emergence of a giant cluster in the universality class of two-dimensional percolation. Moreover, we propose possible schemes to reproduce other networks of particular social contacts, namely sexual contacts.Comment: Phys. Rev. Lett. (in press

    Atomic Diffusion and Mixing in Old Stars. III. Analysis of NGC 6397 Stars under New Constraints

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    We have previously reported on chemical abundance trends with evolutionary state in the globular cluster NGC 6397 discovered in analyses of spectra taken with FLAMES at the VLT. Here, we reinvestigate the FLAMES-UVES sample of 18 stars, ranging from just above the turnoff point (TOP) to the red giant branch below the bump. Inspired by new calibrations of the infrared flux method, we adopt a set of hotter temperature scales. Chemical abundances are determined for six elements (Li, Mg, Ca, Ti, Cr, and Fe). Signatures of cluster-internal pollution are identified and corrected for in the analysis of Mg. On the modified temperature scales, evolutionary trends in the abundances of Mg and Fe are found to be significant at the 2{\sigma} and 3{\sigma} levels, respectively. The detailed evolution of abundances for all six elements agrees with theoretical isochrones, calculated with effects of atomic diffusion and a weak to moderately strong efficiency of turbulent mixing. The age of these models is compatible with the external determination from the white dwarf cooling sequence. We find that the abundance analysis cannot be reconciled with the strong turbulent-mixing efficiency inferred elsewhere for halo field stars. A weak mixing efficiency reproduces observations best, indicating a diffusion-corrected primordial lithium abundance of log {\epsilon}(Li) = 2.57 +- 0.10. At 1.2{\sigma}, this value agrees well with WMAP-calibrated Big-Bang nucleosynthesis predictions.Comment: 14 pages, 5 figures, accepted by Ap

    Model of mobile agents for sexual interactions networks

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    We present a novel model to simulate real social networks of complex interactions, based in a granular system of colliding particles (agents). The network is build by keeping track of the collisions and evolves in time with correlations which emerge due to the mobility of the agents. Therefore, statistical features are a consequence only of local collisions among its individual agents. Agent dynamics is realized by an event-driven algorithm of collisions where energy is gained as opposed to granular systems which have dissipation. The model reproduces empirical data from networks of sexual interactions, not previously obtained with other approaches.Comment: 6 pages, 8 figure

    On a Wing and a Prayer? Challenges for Reducing Armed Violence

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    Most deaths due to violence now occur outside traditional conflict settings. In these contexts, violence is complex and often hard to understand, linked to a variety of conditions, situations and trends which are deeply embedded and difficult to shift without considerable investment, contextual knowledge and risk. Development is indispensible to reducing armed violence, while aid efforts are expected to be informed by rigorous evidence and qualify as good value for money. Therefore, defining and determining success in this field is urgently needed. This policy briefing explores the challenges of generating better evidence as well as how to respond to complexity, proposing where efforts should be focused.UK Department for International Developmen

    The dune size distribution and scaling relations of barchan dune fields

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    Barchan dunes emerge as a collective phenomena involving the generation of thousands of them in so called barchan dune fields. By measuring the size and position of dunes in Moroccan barchan dune fields, we find that these dunes tend to distribute uniformly in space and follow an unique size distribution function. We introduce an analyticalmean-field approach to show that this empirical size distribution emerges from the interplay of dune collisions and sand flux balance, the two simplest mechanisms for size selection. The analytical model also predicts a scaling relation between the fundamental macroscopic properties characterizing a dune field, namely the inter-dune spacing and the first and second moments of the dune size distribution.Comment: 6 pages, 4 figures. Submitted for publicatio
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