The role of neighbours selection on cohesion and order of swarms

We introduce a multi-agent model for exploring how selection of neighbours determines some aspects of order and cohesion in swarms. The model algorithm states that every agents' motion seeks for an optimal distance from the nearest topological neighbour encompassed in a limited attention field. Despite the great simplicity of the implementation, varying the amplitude of the attention landscape, swarms pass from cohesive and regular structures towards fragmented and irregular configurations. Interestingly, this movement rule is an ideal candidate for implementing the selfish herd hypothesis which explains aggregation of alarmed group of social animals.Comment: 15 pages, 9 figures, Plos One, May 201

Conventions spreading in open-ended systems

We introduce a simple open-ended model that describes the emergence of a shared vocabulary. The ordering transition toward consensus is generated only by an agreement mechanism. This interaction defines a finite and small number of states, despite each individual having the ability to invent an unlimited number of new words. The existence of a phase transition is studied by analyzing the convergence times, the cognitive efforts of the agents and the scaling behavior in memory and timeComment: 11 pages, 5 figure

Analysis of a spatial Lotka-Volterra model with a finite range predator-prey interaction

We perform an analysis of a recent spatial version of the classical Lotka-Volterra model, where a finite scale controls individuals' interaction. We study the behavior of the predator-prey dynamics in physical spaces higher than one, showing how spatial patterns can emerge for some values of the interaction range and of the diffusion parameter.Comment: 7 pages, 7 figure

Consequence of reputation in an open-ended Naming Game

We study a modified version of the Naming Game, a recently introduced model which describes how shared vocabulary can emerge spontaneously in a population without any central control. In particular, we introduce a new mechanism that allows a continuous interchange with the external inventory of words. A novel playing strategy, influenced by the hierarchical structure that individuals' reputation defines in the community, is implemented. We analyze how these features influence the convergence times, the cognitive efforts of the agents and the scaling behavior in memory and time.Comment: 6 pages, 6 figure

Crystal structure and crystal chemistry of fluorannite and its relationships to annite

This contribution deals about the crystal chemical characterization of fluorannite from Katugin Ta-Nb deposit, Chitinskaya Oblast’, Kalar Range, Transbaikalia, Eastern-Siberian Region, Russia. The mineral chemical formula is (K0.960Na0.020Ba0.001) (Fe2+2.102Fe3+0.425Cr3+0.002Mg0.039Li0.085Ti0.210Mn0.057) (Al0.674 Si3.326) O10 (F1.060OH0.028O0.912). This mica belongs to 1M polytype (space group C2/m) with layer parameters a = 5.3454(2) Å, b = 9.2607(4) Å, c = 10.2040(5) Å, beta = 100.169(3)°. Structure refinement, using anisotropic displacement parameters, converged at R = 0.0384. When compared to annite, fluorannite shows a smaller cell volume (Vfluorannite = 497.19 Å3; Vannite = 505.71 Å3), because of its smaller lateral dimensions and its reduced c parameter. The flattening of the tetrahedral basal oxygen atoms plane decreases with F content, together with the A-O4 distance (i.e., the distance between interlayer A cation and the octahedral anionic position) because of the reduced repulsion between the interlayer cation and the anion sited in O4

Boomerang effect of cultural self-awareness : a heuristic study

Considering my recent immigration to Canada, and understanding that my identity has been profoundly shaped by the culture of the group in which I grew up, I became interested in investigating the possible impact of my cultural background in the therapeutic relationships with my clients; a concern that led me to the discussion of cultural awareness . With the demographics continuously changing around the globe, the literature in the field of mental health demonstrates the increasing need for cultural awareness in order to avoid cultural assimilation or malpractice in the clinical and research settings. There is, however, a lack of practical examples of how professionals can actually achieve such awareness. Founded on the ideas of Edward T. Hall (1976), the purpose of this heuristic self-inquiry is to share the path I took to expand my own cultural awareness, and, by doing so, to demonstrate that an art therapist could approach such a task by leaving her or his comfort zone and creatively working with possible countertransferences to the experience. During a two-month cross-cultural art therapy experience in Peru, I investigated my own cultural countertransferences through visual and written journals. As I journeyed inward, 'forgotten' cultural assumptions and worldviews that were rooted in my childhood surfaced to my conscious mind: they haunted my dreams, stirred my emotions, and culminated in an encounter with the Shadow side of my personality. Now I remember; now I am more awar

Structural properties of adsorbent phyllosilicates rule the entrapping ability of intercalated iron-phenanthroline complex towards thiols

The interaction of volatile organic sulfur derivatives, such as 1-heptanethiol (C7H16S), with clay minerals treated with a μ-oxo Fe3+-phenanthroline 1:1 complex results strongly affected by crystal chemical properties of pristine mineral phases. In particular, two sepiolite clays with different structural features demonstrated significantly different ability to immobilize the Fe3+-phenanthroline complex at two pH values (pH = 5.4 and pH = 2.3). The most effective binding was obtained with sepiolite with higher structural disorder at pH 5.4. Accordingly, the resulting hybrid material showed also the greatest efficiency in removal of thiol in gas phase. A direct correlation can be established between the adsorption of the Fe3+-phenanthroline complex and the gas binding process at room temperature. In fact, 1-heptanethiol entrapping occurs via redox reactions between Fe3+ and a first thiol molecule to give the reduced Fe2+-phenanthroline complex and disulfide, followed by the binding of further thiols to the reduced metal centre. The extremely high amount of thiol immobilized by the hybrid material also suggests the co-presence of a catalytic mechanism that guarantees the reoxidation of Fe+2 to Fe+3 and the restoration of redox reactions with thiol. Investigation and conclusions were supported by the several experimental techniques: elemental analysis, X-ray powder diffraction analyses, UV–Vis measurements, FT-IR and NMR spectroscopies, thermogravimetric analyses