What Determines Firm Size?

Motivated by theories of the firm, which we classify as technological' or organizational,' we analyze the determinants of firm size across industries and across countries in a sample of 15 European countries. We find that, on average, firms facing larger markets are larger. At the industry level, we find firms in the utility sector are large, perhaps because they enjoy a natural, or officially sanctioned, monopoly. Capital intensive industries, high wage industries, and industries that do a lot of R&D have larger firms, as do industries that require little external financing. At the country level, the most salient findings are that countries with efficient judicial systems have larger firms, and, correcting for institutional development, there is little evidence that richer countries have larger firms. Interestingly, institutional development, such as greater judicial efficiency, seems to be correlated with lower dispersion in firm size within an industry. The effects of interactions (between an industry's characteristics and a country's environment) on size are perhaps the most novel results in the paper, and are best able to discriminate between theories. As the judicial system improves, the difference in size between firms in capital intensive industries and firms in industries that use little physical capital diminishes, a finding consistent with size of firms in industries dependent on external finance is larger in countries with better financial markets, suggesting that financial constraints limit average firm size.

Toward high performance renewable agave reinforced biocomposites: Optimization of fiber performance and fiber-matrix adhesion analysis

The increasing sensitivity toward the environmental pollution and the recent laws on the environmental protection, have led to an increasing attention to the so called biocomposites, i.e. to ecofriendly or renewable composite materials, obtained from biopolymers reinforced by natural fibers. Although the contribution of various works reported in literature, focused on biocomposites reinforced by agave fibers, such materials are still exclusively used in the automotive industry for non-structural applications, and the implementation of high performance biocomposites for semi-structural and structural applications, is an expected, but not yet reached objective. Therefore, the present work aims to give a contribution to reach such an objective, by means of a proper selection of the fiber, in terms of variety, age and position, as well as by the implementation of a new ecofriendly fiber extraction method that allows the user to obtain fibers with improved mechanical performance. In more detail, it is shown that the agave marginata, widespread in the Mediterranean area, provides fiber with performance higher than the agave sisalana commonly considered in literature, and its performance can be furtherly improved by proper optimization of the main influence parameters and the extraction process. On the basis of these optimized fibers, as well as of thermoplastic and thermosetting matrixes, particularly suitable for the manufacturing of high performance ecofriendly biocomposites, an accurate theoretical-experimental analysis on the fiber-matrix adhesion has allowed first to confirm the good adhesion of the agave with epoxy and PLA matrixes, as well as to detect the actual influence of the mercerization treatments and the significant effects of the stiffness of the coupled materials on the potential pull-out and/or debonding damage mechanisms

Progettazione efficiente di Biocompositi Rinforzati con fibre di Agave

La crescente sensibilit\ue0 nei riguardi dell'inquinamento ambientale e le nuove disposizioni legislative in materia di protezione dell'ambiente, hanno portato negli ultimi anni ad una crescente attenzione verso i cosiddetti biocompositi, cio\ue8 verso materiali compositi ecocompatibili e/o rinnovabili, ottenuti da biopolimeri rinforzati da fibre naturali come lino, kenaf, agave ecc. Il presente lavoro intende dare un contributo alla comprensione del comportamento meccanico ed alla efficiente progettazione di performanti biocompositi, ottenuti attraverso una oculata scelta di matrici termoindurenti e termoplastiche, rinforzate con fibre di agave. Dopo avere indagato sulle peculiari propriet\ue0 delle fibre di agave, attraverso prove di trazione e prove di pull-out su singola fibra, nonch\ue9 sulle effettive propriet\ue0 delle matrici selezionate, si propongono modelli teorici e di micromeccanica che descrivono correttamente il comportamento meccanico di tali biocompositi. Verifiche sperimentali, eseguite su biocompositi a fibre corte e lunghe hanno consentito di correlare le propriet\ue0 meccaniche ai particolari meccanismi di danneggiamento, confermando la bont\ue0 dei modelli teorici proposti

A better characterization of the chemical composition of exoplanets atmospheres with ARIEL

Since the discovery of the first extrasolar planet more than twenty years ago, nearly four thousand planets orbiting stars other than the Sun (http://exoplanet.eu/) have been discovered. Current observational instruments (on board the Hubble Space Telescope, Spitzer, and on ground-based facilities) have allowed the scientific community to obtain important information on the physical and chemical properties of these planets. However, for a more in-depth characterisation of these worlds, more powerful telescopes are needed. Thanks to the high sensitivity of their instruments, the next generation of space observatories (e.g. JWST, ARIEL) will provide observations of unprecedented quality, allowing us to extract far more information than what was previously possible. Such high quality observations will provide constraints on theoretical models of exoplanet atmospheres and lead to a greater understanding of their physics and chemistry. Important modelling efforts have been carried out during the past few years, showing that numerous parameters and processes (such as the elemental abundances, temperature, mixing, etc.) are likely to affect the atmospheric composition of exoplanets and subsequently the observable spectra. In this manuscript, we review the different parameters that can influence the molecular composition of exoplanet atmospheres. We show that the high-precision of ARIEL observations will improve our view and characterisation of exoplanet atmospheres. We also consider future developments that are necessary to improve atmospheric models, driven by the need to interpret the available observations

Drug discovery for Chagas disease should consider Trypanosoma cruzi strain diversity.

This opinion piece presents an approach to standardisation of an important aspect of Chagas disease drug discovery and development: selecting Trypanosoma cruzi strains for in vitro screening. We discuss the rationale for strain selection representing T. cruzi diversity and provide recommendations on the preferred parasite stage for drug discovery, T. cruzi discrete typing units to include in the panel of strains and the number of strains/clones for primary screens and lead compounds. We also consider experimental approaches for in vitro drug assays. The Figure illustrates the current Chagas disease drug-discovery and development landscape