Symbolic Lookaheads for Bottom-up Parsing

We present algorithms for the construction of LALR(1) parsing tables, and of LR(1) parsing tables of reduced size. We first define specialized characteristic automata whose states are parametric w.r.t. variables symbolically representing lookahead-sets. The propagation flow of lookaheads is kept in the form of a system of recursive equations, which is resolved to obtain the concrete LALR(1) table. By inspection of the LALR(1) automaton and of its lookahead ropagation flow, we decide whether the grammar is LR(1) or not. In the positive case, an LR(1) parsing table of reduced size is computed by refinement of the LALR(1) table

On the Finitary Characterization of pi-Congruences

Some alternative characterizations of late full congruences, either strong or weak, are presented. Those congruences are classically defined by requiring the corresponding ground bisimilarity under all name substitutions. We first improve on those infinitary definitions by showing that congruences can be alternatively characterized in the pi-calculus by sticking to a finitenumber of carefully identified substitutions, and hence, by resorting to only a finite number of ground bisimilarity checks.Then we investigate the same issue in both the ground and the non-ground pi-xsi-calculus, a CCS-like process algebra whose ground version has already been proved to coincide with ground pi-calculus. The pi-xsi-calculus perspective allows processes to be explicitly interpreted as functions of their free names. As aresult, a couple of alternative characterizations of pi-congruences are given, each of them in terms of the bisimilarity of one single pair of pi-xsi-processes. In one case, we exploit lambda-closures of processes, so inducing the effective generationof the substitutions necessary to infer non-ground equivalence. In the other case, a more promising call-by-need discipline for the generation of the wanted substitutions is used. This last strategy is also adopted to show a coincidence result with open semantics. By minor changes, all of the above characterizations for late semantics can be suited for congruences of the early family

Modelling and analysis of biochemical signalling pathway cross-talk

Signalling pathways are abstractions that help life scientists structure the coordination of cellular activity. Cross-talk between pathways accounts for many of the complex behaviours exhibited by signalling pathways and is often critical in producing the correct signal-response relationship. Formal models of signalling pathways and cross-talk in particular can aid understanding and drive experimentation. We define an approach to modelling based on the concept that a pathway is the (synchronising) parallel composition of instances of generic modules (with internal and external labels). Pathways are then composed by (synchronising) parallel composition and renaming; different types of cross-talk result from different combinations of synchronisation and renaming. We define a number of generic modules in PRISM and five types of cross-talk: signal flow, substrate availability, receptor function, gene expression and intracellular communication. We show that Continuous Stochastic Logic properties can both detect and distinguish the types of cross-talk. The approach is illustrated with small examples and an analysis of the cross-talk between the TGF-b/BMP, WNT and MAPK pathways

Process Calculi Abstractions for Biology

Several approaches have been proposed to model biological systems by means of the formal techniques and tools available in computer science. To mention just a few of them, some representations are inspired by Petri Nets theory, and some other by stochastic processes. A most recent approach consists in interpreting the living entities as terms of process calculi where the behavior of the represented systems can be inferred by applying syntax-driven rules. A comprehensive picture of the state of the art of the process calculi approach to biological modeling is still missing. This paper goes in the direction of providing such a picture by presenting a comparative survey of the process calculi that have been used and proposed to describe the behavior of living entities. This is the preliminary version of a paper that was published in Algorithmic Bioprocesses. The original publication is available at http://www.springer.com/computer/foundations/book/978-3-540-88868-

The politics of innovation, entrepreneurship and community as a discursive practice. Researching a startup incubator in Milan.

This study investigates innovation as a discursive field and it aims to answer the following research questions: under what conditions of possibility does the discursive practice “innovation” become subjectively and collectively sensible and meaningful? How does such discourse “speak the truth” to and for the subject? The research explores innovation as a meaningful social fact that, on one side, features ideal and objectified traits as an object of knowledge and, on the other, it socially inscribes itself into reality through spatialization. The analysis problematizes innovation as a social phenomenon that manifests itself in and through spaces –urban, organizational and corporeal, contingently to relational processes and subjective enactments. To answer the research questions, the study performs an analysis of innovation as a discursive field through a genealogical exercise that builds on an ethnographic observation conducted at Core, a startup incubator and co-working space located in Milan. The inquiry moves from the basic consideration that acknowledges as meaningful the relationship between innovation, the city and the urban space at large. Rather than assuming the “city-innovation” nexus as given, the study investigates some of the epistemological grounds, ontological properties and features of the rational discourse underlying innovation (Chapter 1). More precisely, this study begins with a problematization of how innovation is commonly thought and represented as requiring specific spatial conditions to thrive, and how a particular configuration of the object “city” is pre-reflexively implied and imagined when the desideratum “innovation” is evoked. Building upon this first genealogical analysis, the “eventualization” of innovation as a discursive practice is then investigated with reference to Milan’s contemporary social space (Chapter 3). In the chapter, particular attention is paid to key policies and initiatives embraced at the local and national governmental levels from 2011 to 2016. Building on the assumption that for a discourse to materialize into a social practice, organizational and corporeal spaces of configuration are needed, the results of the ethnographic investigation are then presented. The organizational spatial rhetoric and pedagogy are analyzed in order to shed light upon the material conditions of the appearance of the discourse of innovation (Chapter 4). Finally, the relational conditions of possibility for innovation to occur are explored, and the experience of being an “innovative” subject is investigated (Chapter 5). This study offers a contribution to critical social theory and research, as well as to human geography, in two ways. On the one hand, it performs a “methodological journey” to show how certain objects of thought e.g. the urban space, the city or innovation– territorialize in institutions, rituals, “banal” gestures, unconscious and pre-reflexive practices through spatial relations. On the other hand, this work sheds light on the rhetoric of innovation by arguing that it corresponds to a new anthropological discourse rather than being a simple expression of historically contingent economic necessities

Formal executable descriptions of biological systems

The similarities between systems of living entities and systems of concurrent processes may support biological experiments in silico. Process calculi offer a formal framework to describe biological systems, as well as to analyse their behaviour, both from a qualitative and a quantitative point of view. A couple of little examples help us in showing how this can be done. We mainly focus our attention on the qualitative and quantitative aspects of the considered biological systems, and briefly illustrate which kinds of analysis are possible. We use a known stochastic calculus for the first example. We then present some statistics collected by repeatedly running the specification, that turn out to agree with those obtained by experiments in vivo. Our second example motivates a richer calculus. Its stochastic extension requires a non trivial machinery to faithfully reflect the real dynamic behaviour of biological systems

Association between Dietary Habits and Severity of Symptoms in Premenstrual Syndrome

Background. Premenstrual syndrome (PMS) is a set of physical, psychological, and emotional symptoms that occur during the luteal phase of the menstrual cycle. The etiopathogenesis of this condition is not fully understood, and several studies suggest a possible role of environmental factors, such as diet. The aim of this work was to investigate the relationship between dietary habits and the occurrence and severity of PMS. Methods and Results. Forty-seven women were enrolled in the study. Participants were asked to complete the Daily Record of Severity of Problems (DRSP) to diagnose PMS and to complete a three-day food record during the perimenstrual phase. Thirty women completed the study (16 with PMS and 14 controls). An analysis of the food diaries revealed no differences between the women with PMS and the control subjects in terms of total energy intake (1649 vs. 1570 kcal/day), diet composition, and the consumption of macro- or micronutrients, except for copper, whose consumption was higher in women with PMS than in the control subjects (1.27 ± 0.51 vs. 0.94 ± 0.49 mg/d, p < 0.05). Conclusions. The data presented here are very preliminary, and only a significant difference in copper intake was found when comparing women with PMS and controls. Larger studies are needed to better define how diet may contribute to the exacerbation of the psychological and somatic symptoms associated with PMS and whether PMS itself may influence macro- or micronutrient intake by changing dietary habits