Chameleon fields and solar physics

In this article we discuss some aspects of solar physics from the standpoint of the so-called chameleon fields (i.e. quantum fields, typically scalar, where the mass is an increasing function of the matter density of the environment). Firstly, we analyze the effects of a chameleon-induced deviation from standard gravity just below the surface of the Sun. In particular, we develop solar models which take into account the presence of the chameleon and we show that they are inconsistent with the helioseismic data. This inconsistency presents itself not only with the typical chameleon set-up discussed in the literature (where the mass scale of the potential is fine-tuned to the meV), but also if we remove the fine-tuning on the scale of the potential. Secondly, we point out that, in a model recently considered in the literature (we call this model "Modified Fujii's Model"), a conceivable interpretation of the solar oscillations is given by quantum vacuum fluctuations of a chameleon.Comment: 17 pages including figure

Excess money growth and inflation dynamics

The paper analyses the short-run impact of periods of strong monetary growth on inflation dynamics for 15 industrialised economies. We find that, over a 3-year horizon, the positive link between monetary aggregates and prices holds in approximately fifty percent of the cases. An econometric investigation suggests that a contemporaneous increase in the gap measures of the real stock price and real housing price and strong dynamics of loans to the private sector significantly increase the probability of turning an episode of excessive money growth into an inflationary outburst. JEL Classification:inflation, money growth, quantity theory of money

Excess money growth and inflation dynamics

The paper analyzes the short-run impact of periods of strong monetary growth on inflation dynamics for 15 industrialized economies. We find that when robust money growth is accompanied by large increases in stock and house prices and loose credit conditions, the probability of recording an inflationary outburst over a three-year horizon is significantly increased. In contrast, significant money stock expansions which are not associated with sustained credit increases and strong dynamics in other asset prices seem to be less likely to have inflationary consequences and thus, less worrying from a policy perspective.Inflation, money growth, quantity theory of money

Specifying Graph Languages with Type Graphs

We investigate three formalisms to specify graph languages, i.e. sets of graphs, based on type graphs. First, we are interested in (pure) type graphs, where the corresponding language consists of all graphs that can be mapped homomorphically to a given type graph. In this context, we also study languages specified by restriction graphs and their relation to type graphs. Second, we extend this basic approach to a type graph logic and, third, to type graphs with annotations. We present decidability results and closure properties for each of the formalisms.Comment: (v2): -Fixed some typos -Added more reference

OPTIMAL HOMEOMORPHISMS BETWEEN CLOSED CURVES

The concept of natural pseudo-distance has proven to be a powerful tool for measuring the dissimilarity between topological spaces endowed with continuous real-valued functions. Roughly speaking, the natural pseudo-distance is defined as the infimum of the change of the functions' values, when moving from one space to the other through homeomorphisms, if possible. In this paper, we prove the first available result about the existence of optimal homeomorphisms between closed curves, i.e. inducing a change of the function that equals the natural pseudo-distance

Design-time Models for Resiliency

Resiliency in process-aware information systems is based on the availability of recovery flows and alternative data for coping with missing data. In this paper, we discuss an approach to process and information modeling to support the specification of recovery flows and alternative data. In particular, we focus on processes using sensor data from different sources. The proposed model can be adopted to specify resiliency levels of information systems, based on event-based and temporal constraints

Economic Growth and Carbon Dioxide Emissions in Italy, 1861-2003

This paper examines the relationship between economic growth and carbon dioxide emissions in Italy for the period 1861-2003. Using cointegration, rolling regression and error correction modeling techniques, we find that growth and carbon dioxide emissions are strongly interrelated, and elasticity of pollutant emissions with respect to income has been decreasing over time. For the period 1960-2003 EKC estimates provide evidence for the existence of a reasonable "turning point". However, given the heavy dependence of Italian economy upon fossil fuels, meeting the emissions targets in the accomplishing of the Kyoto Protocol is a very challenging task.Environmental Kuznets Curve; Carbon Dioxide Emissions; Time Series Analysis; Italian Economy

Rewriting Abstract Structures: Materialization Explained Categorically

The paper develops an abstract (over-approximating) semantics for double-pushout rewriting of graphs and graph-like objects. The focus is on the so-called materialization of left-hand sides from abstract graphs, a central concept in previous work. The first contribution is an accessible, general explanation of how materializations arise from universal properties and categorical constructions, in particular partial map classifiers, in a topos. Second, we introduce an extension by enriching objects with annotations and give a precise characterization of strongest post-conditions, which are effectively computable under certain assumptions