Dynamical system analysis of ignition phenomena using the tangential stretching rate concept

We analyze ignition phenomena by resorting to the stretching rate concept formerly introduced in the study of dynamical systems. We construct a Tangential Stretching Rate (TSR) parameter by combining the concepts of stretching rate with the decomposition of the local tangent space in eigen-modes. The main feature of the TSR is its ability to identify unambiguously the most energetic scale at a given space location and time instant. The TSR depends only on the local composition of the mixture, its temperature and pressure. As such, it can be readily computed during the post processing of computed reactive flow fields, both for spatially homogeneous and in-homogenous systems. Because of the additive nature of the TSR, we defined a normalized participation index measuring the relative contribution of each mode to the TSR. This participation index to the TSR can be combined with the mode amplitude participation Index of a reaction to a mode – as defined in the Computational Singular Perturbation (CSP) method – to obtain a direct link between a reaction and TSR. The reactions having both a large participation index to the TSR and a large CSP mode amplitude participation index are those contributing the most to both the explosive and relaxation regimes of a reactive system. This information can be used for both diagnostics and for the simplification of kinetic mechanisms. We verified the properties of the TSR with reference to three nonlinear planar models (one for isothermal branched-chain reactions, one for a non-isothermal, one-step system, and for non-isothermal branched-chain reactions), to one planar linear model (to discuss issues associated with non-normality), and to test problems involving hydro-carbon oxidation kinetics. We demonstrated that the reciprocal of the TSR parameter is the proper characteristic chemical time scale in problems involving multi-step chemical kinetic mechanisms, because (i) it is the most relevant time scale during both the explosive and relaxation regimes and (ii) it is intrinsic to the kinetics, that is, it can be identified without the need of any ad hoc assumption

ICT AND THE CHANGING NATURE OF COMPETITION: EVIDENCE FROM INFORMATION INTENSIVE INDUSTRIES IN ITALY

Despite the increasing interest over the transformations induced by ICT on industry structure and competition, there is still not a unified view on the effects of ICT on industrial change. On the one hand, ICT is expected to bring more competition, to reduce entry barriers and to leave more opportunities for small entrepreneurial firms. On the other hand, there is evidence of the increased market concentration favoured by ICT. The changing nature of competition has been so far studied more at firm level and more of the empirical evidence is for highly information intensive economies like the US. This paper tries to bridge this gap analysing 209 industries in Italy between 2002 and 2011. Our results show a significant effect of ICT on industry dynamics. Firstly, we find that information intensive industries showed a higher productivity, a higher market concentration and a greater profit dispersion compared to their counterparts, thus extending related studies that identify mechanisms for ICTenabled value creation in US. Secondly, we do not find phenomena of hi-growth of SMEs in information intensive industries as a consequence of the limited capability of Italian SMEs to use ICT to start hi-growth entrepreneurial ventures, differently from what happens in other countries

Snap4City: A big data platform for smart cities

Since the idea of smart city has become a practice to be implemented, urban planners and policy makers have needed tools that would allow them to exploit the information potential of the amount of data that the city itself produced in order to understand and manage its growing complexity. This article, after examining the close relationship between good governance based on a data-driven approach and the economic and social development of a city, describes the Snap4City Open Source solution, a Big Data Smart City Platform, adopted in European cities and region (Antwerp, Florence, Pisa, Santiago, France, Belgium, Finland, Tuscany, Sardinia, Croatia, Greece, etc.). Snap4City is GDPR compliant and designed to support city planners, combining strong tools for data integration, analytics, forecasting and visualization with the possibility of set Living Labs to enhance the collaboration among operators. Four scenarios have been selected and described (a. Florence Smart City Control Room; b. Traffic Flow Reconstruction and Air Quality predictions in Firenze, Pisa, Livorno; c. Air Quality in Helsinki for the citizens; d. People flows in Antwerp). The main KPIs have been briefly exposed, in order to evaluate the Snap4city impact in Smart City planning

The european paediatric legislation: benefits and perspectives

BACKGROUND: The lack of availability of appropriate medicines for children is an extensive and well known problem. Paediatricians and Physicians who take care of the paediatric population are primarily exposed to cope with this negative situation very often as more than half of the children are prescribed off-label or unlicensed medicines.DISCUSSION: Medicinal products used to treat this population should be subjected to ethical research of high quality and be explicitly authorized for use in children as it happens in adults. For that reason, and following the US experience, the European Paediatric Regulation has been amended in January 2007 by the European Commission. The objective of the Paediatric Regulation is to improve the development of high quality and ethically researched medicines for children aged 0 to 17 years, to facilitate the availability of information on the use of medicines for children, without subjecting children to unnecessary trials, or delaying the authorization of medicines for use in adults.SUMMARY: The Paediatric Regulation is dramatically changing the regulatory environment for paediatric medicines in Europe and is fuelling an increased number of clinical trials in the paediatric population. Nevertheless, there are some risks and pitfalls that need to be anticipated and controlled in order to ensure that children will ultimately benefit from this European initiative

Emergence In the Loop: Simulating the two way dynamics of norm innovation

In this paper we will present the EMIL project, "EMergence In the Loop: Simulating the two-way dynamics of norm innovation", a three-year project funded by the European Commission (Sixth Framework Programme -Information Society and Technologies) in the framework of the initiative "Simulating Emergent Properties in Complex Systems". The EMIL project intends to contribute to the study of social complex systems by modelling norm innovation as a phenomenon implying interrelationships among multiple levels. It shall endeavour to point out that social dynamics in societies of intelligent agents is necessarily bi-directional, which adds complexity to the emergence processes. The micro-macro link will be modelled and observed in the emergence of properties at the macro-level and their immergence into the micro-level units. The main scientific aim of the EMIL project is to construct a simulator for exploring and experimenting norm-innovation

Obesity in patients with acute lymphoblastic leukemia in childhood

Acute lymphoblastic leukemia is the most common malignancy in childhood. Continuous progress in risk-adapted treatment for childhood acute lymphoblastic leukemia has secured 5-year event-free survival rates of approximately 80% and 8-year survival rates approaching 90%. Almost 75% of survivors, however, have a chronic health condition negatively impacting on cardiovascular morbidity and mortality. Obesity can be considered one of the most important health chronic conditions in the general population, with an increasing incidence in patients treated for childhood cancers and especially in acute lymphoblastic leukemia survivors who are, at the same time, more at risk of experiencing precocious cardiovascular and metabolic co-morbidities. The hypothalamic-pituitary axis damage secondary to cancer therapies (cranial irradiation and chemotherapy) or to primary tumor together with lifestyle modifications and genetic factors could affect long-term outcomes. Nevertheless, the etiology of obesity in acute lymphoblastic leukemia is not yet fully understood. The present review has the aim of summarizing the published data and examining the most accepted mechanisms and main predisposing factors related to weight gain in this particular population