Hypergraph Laplace Operators for Chemical Reaction Networks

We generalize the normalized combinatorial Laplace operator for graphs by defining two Laplace operators for hypergraphs that can be useful in the study of chemical reaction networks. We also investigate some properties of their spectra.Comment: 23 pages, 7 figure

Fiscal Adjustments and the Short-Term Trade-Off between economic growth and equality

This article examines the short-term economic impact of alternative fiscal adjustment strategies, with an especial focus on their effect on economic growth and income distribution Based on a sample of 53 adjustment episodes occurred in the fifteen EU Member States between 1960-2000, this article shows that different strategies of fiscal adjustment bring about different economic consequences. Expenditure-based adjustments that are preceded by bad economic and fiscal initial conditions, that are accompanied by a devaluation, and that succeed in cutting the least productive expenditures of the budget, are likely to have anti-Keynesian effects and to be expansionary. Nevertheless, they do so at the expense of increasing income inequality. The opposite is true for revenue-based consolidations. The nineties epitomize the story of expansionary fiscal consolidations via strong wealth and credibility effects, but also the rebirth of the trade-off between growth and equality, mediated by fiscal policy.Fiscal adjustment, economic growth, equality, budget composition.

Diagnostics for specific PAHs in the far-IR: searching neutral naphthalene and anthracene in the Red Rectangle

Context. In the framework of the interstellar polycyclic aromatic hydrocarbons (PAHs) hypothesis, far-IR skeletal bands are expected to be a fingerprint of single species in this class. Aims. We address the question of detectability of low energy PAH vibrational bands, with respect to spectral contrast and intensity ratio with ``classical'' Aromatic Infrared Bands (AIBs). Methods. We extend our extablished Monte-Carlo model of the photophysics of specific PAHs in astronomical environments, to include rotational and anharmonic band structure. The required molecular parameters were calculated in the framework of the Density Functional Theory. Results. We calculate the detailed spectral profiles of three low-energy vibrational bands of neutral naphthalene, and four low-energy vibrational bands of neutral anthracene. They are used to establish detectability constraints based on intensity ratios with ``classical'' AIBs. A general procedure is suggested to select promising diagnostics, and tested on available Infrared Space Observatory data for the Red Rectangle nebula. Conclusions. The search for single, specific PAHs in the far-IR is a challenging, but promising task, especially in view of the forthcoming launch of the Herschel Space Observatory.Comment: 13 pages, 13 figures, accepted for publication in A&

Duration of Fiscal Budgetary Consolidations in the European Union

This paper examines the duration of fiscal consolidations among the fifteen EU Members States using data from the European Commission for the period 1960-2000. Using the duration model approach, we estimate the hazard and survivor functions of our series. Then we discuss what is the duration model that best fits our data, and which are the explanatory variables that best exp lain the probability of ending a fiscal consolidation period. We also deal with those aspects related to sample heterogeneity and the sensitivity of the results to different possible definitions of fiscal adjustment. We find evidence that the probability of ending a period of fiscal consolidation depends on the debt level, the magnitude of the adjustment, the extent of expenditure cuts, and the degree of cabinet fragmentation. We also find that under a stricter definition of fiscal consolidation, political variables, such as coalition size and election year, gain importance with respect to economic variables as predictors of the probability of ending a fiscal consolidation period.

Fiscal discipline and exchange rates : does politics matter?

We look at the effect of exchange rate regimes on fiscal discipline, taking into account the effect of underlying political conditions. We present a model where strong politics (defined as policymakers facing longer political horizon and higher cohesion) are associated with better fiscal performance, but fixed exchange rates may revert this result and lead to less fiscal discipline. We confirm these hypotheses through regression analysis performed on a panel sample covering 79 countries from 1975 to 2012. Our empirical results also show that the positive effect of strong politics on fiscal discipline is not enough to counter the negative impact of being at/moving to fixed exchange rates. Our results are robust to a number of important sensitivity checks, including different estimators, alternative proxies for fiscal discipline, and sub-sample analysis.info:eu-repo/semantics/publishedVersio

30 years of cosmic fullerenes

In 1985, "During experiments aimed at understanding the mechanisms by which long-chain carbon molecules are formed in interstellar space and circumstellar shells", Harry Kroto and his collaborators serendipitously discovered a new form of carbon: fullerenes. The most emblematic fullerene (i.e. C$_{60}$ "buckminsterfullerene"), contains exactly 60 carbon atoms organized in a cage-like structure similar to a soccer ball. Since their discovery impacted the field of nanotechnologies, Kroto and colleagues received the Nobel prize in 1996. The cage-like structure, common to all fullerene molecules, gives them unique properties, in particular an extraordinary stability. For this reason and since they were discovered in experiments aimed to reproduce conditions in space, fullerenes were sought after by astronomers for over two decades, and it is only recently that they have been firmly identified by spectroscopy, in evolved stars and in the interstellar medium. This identification offers the opportunity to study the molecular physics of fullerenes in the unique physical conditions provided by space, and to make the link with other large carbonaceous molecules thought to be present in space : polycyclic aromatic hydrocarbons.Comment: To appear in the Proceedings of the annual meeting of the French society of astronomy and astrophysics (SF2A 2015

Spatial distribution of R&D expenditure and patent applications across EU regions and its impact on economic cohesion

This article explores the spatial distribution of regional technology indicators in the EU over the last decade and its impact on cohesion. Thus, we find that public R&D spending and patent applications have converged among regions during the nineties. On the other hand, private R&D activities have diverged, as a result of an asymmetric expansion during the second half of the nineties. We show that when the dispersion of public R&D across regions diminished in the second half of the nineties, income disparities at regional level also decreased. Therefore, while technology policy based on efficiency criteria should remain as a policy tool for economic growth, this policy should be counterbalanced by R&D funds to the least developed regions to maintain economic cohesion.