2,404 research outputs found
Investment-Cash Flow Sensitivities are not Valid Measures of Financing Constraints
No full textKaplan and Zingales [1997] provide both theoretical arguments and empirical evidence that investment-cash flow sensitivities are not good indicators of financing constraints. Fazzari, Hubbard and Petersen [1999] criticize those findings. In this note, we explain how the Fazzari et al. [1999] criticisms are either very supportive of the claims in Kaplan and Zingales [1997] or incorrect. We conclude with a discussion of unanswered questions.
Stanislao Cannizzaro and the Development of Chemistry in Palermo from 1862 to 1871
No full textStanislao Cannizzaro worked at Palermo University for about ten years. There he managed to
establish a modern and well-equipped chemical laboratory. His international fame attracted co-
workers even from abroad: Naquet, Lieben, and Körner came to Palermo to work with him. This
greatly improved the quality of teaching and of research in Palermo, which became a worldwide
acknowledged center of chemical culture. In Palermo, atomic-molecular theory was extensively
taught and research was carried out on chemical atomicity (valence) and spatial structures of both
aliphatic and aromatic organic molecules: Körner found the relative positions of substituent groups
on the benzene ring, Paternò proved the equivalence of the four positions around each carbon atom.
Thanks to Cannizzaro s and Paternò s efforts, a new journal, Gazzetta Chimica Italiana, was
printed in Palermo. The journal collected original papers from Italian chemists, and summaries or
translations of foreign ones. When Cannizzaro moved to Rome in 1872, Emanuele Paternò, the
youngest of his pupils, took his place. Eventually, Paternò also moved to Rome, and the leading
role of Palermo in Italian chemistry faded
Wave propagation in 1D elastic solids in presence of long-range central interactions
No full textIn this paper wave propagation in non-local elastic solids is examined in the framework of the mechanically based non-local elasticity theory established by the author in previous papers. It is shown that such a model coincides with the well-known Kroner-Eringen integral model of non-local elasticity in unbounded domains. The appeal of the proposed model is that the mechanical boundary conditions may easily be imposed because the applied pressure at the boundaries of the solid must be equilibrated by the Cauchy stress. In fact, the long-range forces between different volume elements are modelled, in the body domain, as central body forces applied to the interacting elements. It is shown that the shape change of travelling disturbances coalesces with those predicted by the non-local integral theory of elasticity in unbounded domains, but several differences arise in the case of bounded domains. The wave propagation problem has been formulated by means of the Hamiltonian functional of the proposed mechanically based model of non-local elasticity, introducing an additional term to the elastic potential energy that accounts for elastic long-range interactions. In this way, the wave equation may be obtained in a weak formulation and be further used to provide approximate analytical solutions to the governing equation in the context of standing wave analysis. An equivalent discrete point-spring model, similar to lattice-type networks, has also been introduced to show the mechanical equivalence of the non-local elastic model as well as to provide a mechanical scheme suitable for the numerical treatment of pressure waves travelling in non-local bounded domains
Raffaele Piria e Stanislao Cannizzaro, dal 1848 al 1860 e oltre: due chimici meridionali nell'Italia Risorgimentale e post-unitaria
No full textCome altri scienziati italiani a metà ottocento, Raffaele Piria e Stanislao Cannizzaro, con la loro attività scientifica e politica, hanno dato un notevole contributo, non solo al progresso della Chimica, ma anche alla costituzione del Regno d’Italia. La loro continua e lungimirante attività, sia sui campi di battaglia che nelle aule universitarie o parlamentari, ha contribuito alla rinascita culturale, sociale ed economica del Paese.
Questo articolo, completato a conclusione dell’Anno Internazionale della Chimica, e delle celebrazioni per il 150° anniversario della fondazione dello stato italiano, vuole ricordare la loro attività politica e scientifica, sia in ambito locale, che nazionale, che internazionale
La ricerca dei componenti ultimi della materia:l'approccio filosofico, quello chimico e quello fisico
No full textStanislao Cannizzaro: vita e opere nel contesto palermitano
No full textE' descritta l'attività politica, scientifica e didattica di Stanislao Cannizzaro a Palermo, nel decennio 1862-1871, in particolare nei riguardi delle fondazione e dello sviluppo dell'Istituto Tecnico. Tra gli altri risultati, l'aver incoraggiato e agevolato la crescita scientifica di due giovani talenti, il tedesco Guglielmo Koerner e il palermitano Emanuele Paternò, che diedero un contributo fondamentale allo sviluppo della chimica organica ottocentesca
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