Theatre to motivate the study of physics

A survey we carried out in upper secondary schools showed that the majority of the students consider physics as an important resource, yet as essentially connected to technology in strict terms, and not contributing \u201cculture\u201d, being too difficult a subject. Its appreciation tends to fade as their education progresses through the grades. The search for physics communication methods to increase interest and motivation among students prompted the Department of Physics at the University of Milan to establish the Laboratory of ScienzATeatro (SAT) in 2004. Up to May 2010, SAT staged three shows and one lesson-show having physics as a main theme, for students attending any grades at school. Good indicators of the efficacy of those shows are: the number of repeats (256 of them up to May 2010), the reputation of the theatres in which they were performed, and the results of two surveys on the achievement of the goals, which saw the participation of over 50 classes each

Orchestrating Tuple-based Languages

The World Wide Web can be thought of as a global computing architecture supporting the deployment of distributed networked applications. Currently, such applications can be programmed by resorting mainly to two distinct paradigms: one devised for orchestrating distributed services, and the other designed for coordinating distributed (possibly mobile) agents. In this paper, the issue of designing a pro- gramming language aiming at reconciling orchestration and coordination is investigated. Taking as starting point the orchestration calculus Orc and the tuple-based coordination language Klaim, a new formalism is introduced combining concepts and primitives of the original calculi. To demonstrate feasibility and effectiveness of the proposed approach, a prototype implementation of the new formalism is described and it is then used to tackle a case study dealing with a simplified but realistic electronic marketplace, where a number of on-line stores allow client applications to access information about their goods and to place orders

A semantic deconstruction of session types

We investigate the semantic foundations of session types, by revisiting them in the abstract setting of labelled transition systems. The crucial insight is a simulation relation which generalises the usual syntax-directed notions of typing and subtyping, and encompasses both synchronous and asynchronous binary session types. This allows us to extend the session types theory to some common programming patterns which are not typically considered in the session types literature

A Calculus for Orchestration of Web Services

We introduce COWS (Calculus for Orchestration of Web Services), a new foundational language for SOC whose design has been influenced by WS-BPEL, the de facto standard language for orchestration of web services. COWS combines in an original way a number of ingredients borrowed from well-known process calculi, e.g. asynchronous communication, polyadic synchronization, pattern matching, protection, delimited receiving and killing activities, while resulting different from any of them. Several examples illustrates COWS peculiarities and show its expressiveness both for modelling imperative and orchestration constructs, e.g. web services, flow graphs, fault and compensation handlers, and for encoding other process and orchestration languages

Simulation study of Non-ergodicity Transitions: Gelation in Colloidal Systems with Short Range Attractions

Computer simulations were used to study the gel transition occurring in colloidal systems with short range attractions. A colloid-polymer mixture was modelled and the results were compared with mode coupling theory expectations and with the results for other systems (hard spheres and Lennard Jones). The self-intermediate scattering function and the mean squared displacement were used as the main dynamical quantities. Two different colloid packing fractions have been studied. For the lower packing fraction, $\alpha$-scaling holds and the wave-vector analysis of the correlation function shows that gelation is a regular non-ergodicity transition within MCT. The leading mechanism for this novel non-ergodicity transition is identified as bond formation caused by the short range attraction. The time scale and diffusion coefficient also show qualitatively the expected behaviour, although different exponents are found for the power-law divergences of these two quantities. The non-Gaussian parameter was also studied and very large correction to Gaussian behaviour found. The system with higher colloid packing fraction shows indications of a nearby high-order singularity, causing $\alpha$-scaling to fail, but the general expectations for non-ergodicity transitions still hold.Comment: 13 pages, 15 figure

The limited role of galaxy mergers in driving stellar mass growth over cosmic time

© The Author(s) 2017. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited. Published by Oxford University Press on behalf of the Royal Astronomical Society.A key unresolved question is the role that galaxy mergers play in driving stellar mass growth over cosmic time. Recent observational work hints at the possibility that the overall contribution of `major' mergers (mass ratios $\gtrsim$1:4) to cosmic stellar mass growth may be small, because they enhance star formation rates by relatively small amounts at high redshift, when much of today's stellar mass was assembled. However, the heterogeneity and relatively small size of today's datasets, coupled with the difficulty in identifying genuine mergers, makes it challenging to $\textit{empirically}$ quantify the merger contribution to stellar mass growth. Here, we use Horizon-AGN, a cosmological hydrodynamical simulation, to comprehensively quantify the contribution of mergers to the star formation budget over the lifetime of the Universe. We show that: (1) both major and minor mergers enhance star formation to similar amounts, (2) the fraction of star formation directly attributable to merging is small at all redshifts (e.g. $\sim$35 and $\sim$20 per cent at z$\sim$3 and z$\sim$1 respectively) and (3) only $\sim$25 per cent of today's stellar mass is directly attributable to galaxy mergers over cosmic time. Our results suggest that smooth accretion, not merging, is the dominant driver of stellar mass growth over the lifetime of the Universe.Peer reviewedFinal Published versio

European Space Agency experiments on thermodiffusion of fluid mixtures in space

Abstract.: This paper describes the European Space Agency (ESA) experiments devoted to study thermodiffusion of fluid mixtures in microgravity environment, where sedimentation and convection do not affect the mass flow induced by the Soret effect. First, the experiments performed on binary mixtures in the IVIDIL and GRADFLEX experiments are described. Then, further experiments on ternary mixtures and complex fluids performed in DCMIX and planned to be performed in the context of the NEUF-DIX project are presented. Finally, multi-component mixtures studied in the SCCO project are detailed

“There Are no Things Inside Things”: An Augmented Lecture to Bridge the Gap Between Formal and Informal Physics Education

After 13 years of research about how to make scientific theater a pow-erful tool in physics education [see for instance: 1-3], the group \u201cLo Spettacolo della Fisica\u201d (The Physics Show) (http://spettacolo.fisica.unimi.it) of the Uni-versity of Milan, together with Stefano Oss of the University of Trento and An-drea Brunello of the Arditodesio Theater Company (Trento, Italy) created and developed the idea of \u201cAugmented Lectures\u201d (ALs). These are lectures per-formed in a theatrical setting with the help of professional actors (and/or of paint-ers, musicians, cooks, etc.) with the aim not only to create fascination and passion for physics, but to make people think and reflect on some specific disciplinary topic as well. Although ALs do not need any specific disciplinary preparation, they can, nonetheless, be seen as complementary lectures that can be part of a secondary, or even of a university, formal path in physics. In the augmented lec-ture titled, \u201cThere Are No Things Inside Things\u201d (TANTIT), the theme \u201cwhat is understanding?\u201d is tackled starting from the proprieties of a magnet and devel-oped with the analysis of the double slit experiment in different settings: from the \u201cclassical\u201d photons and electrons experiments, up to those with atoms, fullerenes and tetraphenylporphyrin. Experiments with neutrons and interaction-free meas-urements are also analysed. At the basis of quantum mechanics, there is elegance and simplicity; and it is precisely the simplicity of this theory \u2013 clearly related to its power \u2013 that upsets us, because, on the contrary, the world we are used to is complicated. Some of the peculiarities of quantum physics, and of the conceptual challenges they present to the descendants of fruit pickers and animal hunters as we are, are therefore a stimulus to discuss the meaning of explaining and under-standing, in physical sciences [4]. A physicist (the author) and an actor (Giacomo Anderle) act together with real data, experiments, songs, dances, equations \u2013 also involving the audience on stage \u2013 having in mind that culture is culture only if it changes your life. The aims and the structure of the augmented lecture TANTIT firstly performed inside the \u201cTeatro della Meraviglia\u201d (Theater of Wonder) festi-val in Trento (www.teatrodellameraviglia.it/) will be presented and briefly dis-cussed together with its potentialities