Symmetry Breaking in d-Dimensional Self-gravitating Systems

Systems with long-range interactions, such as self-gravitating clusters and magnetically confined plasmas, do not relax to the usual Boltzmann-Gibbs thermodynamic equilibrium, but become trapped in quasi-stationary states (QSS) the life time of which diverges with the number of particles. The QSS are characterized by the lack of ergodicity which can result in a symmetry broken QSS starting from a spherically symmetric particle distribution. We will present a theory which allows us to quantitatively predict the instability threshold for spontaneous symmetry breaking for a class of d-dimensional self-gravitating systems.Comment: 5 pages, 4 figures. Accepted for publication in Physical Review Letter

Arianna: towards a new paradigm for assistive technology at home

Providing elderly and people with special needs to retain their independence as long as possible is one of the biggest challenges of the society of tomorrow. Teseo, a startup company spinoff from the University of Genoa, aims at accelerating the transition towards a sustainable healthcare system. Teseo's first concept and product, Arianna, allows for the automated recognition of activities of daily living at home and acts as a wellbeing and healthcare personalized assistant. This abstract outlines the main concepts underlying its features and capabilities.Comment: Paper accepted at the Eight Italian Forum on Ambient Assisted Living (ForItAAL 2017

Water in a Polymeric Electrolyte Membrane: Sorption/Desorption and Freezing phenomena

Nafion is a perfluorosulfonated polymer, widely used in Proton Exchange Membrane Fuel Cells. This polymer adopts a complex structural organisation resulting from the microsegregation between hydrophobic backbones and hydrophilic sulfonic acid groups. Upon hydration appear water-filled channels and cavities, in which are released the acidic protons to form a solution of hydronium ions in water embedded in the polymer matrix. Below 273 K, a phenomenon of water sorption/desorption occurs, whose origin is still an open question. Performing neutron diffraction, we monitored the quantity of ice formed during the sorption/desorption as a function of temperature down to 180 K. Upon cooling, we observe that ice forms outside of the membrane and crystallises in the hexagonal Ih form. Simultaneously, the membrane shrinks and dehydrate, leading to an increase of the hydronium ions concentration inside the matrix. Reversibly, the ice melts and the membrane re-hydrate upon heating. A model of solution, whose freezing point varies with the hydronium concentration, is proposed to calculate the quantity of ice formed as a function of temperature. The quantitative agreement between the model and experimental data explains the smooth and reversible behavior observed during the sorption or desorption of water, pointing out the origin of the phenomena. The proposed picture reconciles both confinement and entropic effects. Other examples of water filled electrolyte nano-structures are eventually discussed, in the context of clarifying the conditions for water transport at low temperature

Laws of nature: metaphysics and epistemology

The debate on the metaphysics of laws of nature is one of the many disputes in the metaphysics of science that emerged in the lasts decades of the 20th century. It is historically rooted in the discussions on the role of Divine will in the governance of natural phenomena, held during the 16th to 18th centuries.  However, its most immediate antecedent is a pressing point in the agenda of the Received View: the task of settling a distinction between authentic scientific laws and mere accidentally true generalizations. In this context the discussion was mainly about the logical, semantic and syntactic properties of lawlike statements that could underpin the distinction. Conversely, the current debate on the metaphysics of laws presupposes that mere linguistic or logical considerations are insufficient to draw that distinction and something else is needed. That something else is frequently a feature of the world that falls under the domain of metaphysics, a law of nature, as opposed to a scientific lawlike statement. Not every position in the debate would happily admit that laws are something in the world, but all of them agree on the fact that some metaphysical theorization about the world's structure is needed in order to settle the distinction between laws and non-laws.Fil: Borge, Bruno José. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Filosofía y Letras; ArgentinaFil: Cani, Renato. Universidade Federal de Santa Catarina; Brasi

Potencial expressivo nos jogos indie e gamearte : Breve análise dos jogos Flower e Journey

Digital games have been shown to be a powerful expressive and communicative medium, struggling against the traditional view of games as shallow media. It’s especially at indie games space that there has been a greater experimentation, shifting this paradigm. Flower and Journey are in this indie universe, and these games have reached a great success in many spheres, helping this paradigm shift and favoring a new way to face digital games. The objective of this work is to reflect about the gameplay experience of both games, showing how these games innovated and helping to understand why these games have reached an important position on last years