476 research outputs found

    Euro area money demand and international portfolio allocation: a contribution to assessing risks to price stability

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    The long-run relationship between money and prices in the euro area embedded in traditional money demand models with income and interest rates broke down after 2001. We develop a money demand model where investors hold a diversified portfolio with money, domestic and foreign stocks and long-term bonds in which, in addition to the classical wealth effect, also a size and an international portfolio allocation effects arise. The estimated model identifies three cointegrating vectors stable over the sample 1980-2007: a long-run money demand, which depends on income and all risky assets' returns, and two equilibria for the euro area and the US financial markets. Steady state equilibrium of nominal M3 growth is estimated to be about 7% in 2007 with large standard errors mainly due to uncertainty in asset prices. The gap between actual euro area M3 growth and model-based fitted or predicted values helps forecast euro area inflation. JEL Classification: E41, E44, E52, G11, G15Euro area money demand, Inflation forecasts, monetary policy, portfolio allocation

    Euro area money demand and international portfolio allocation: a contribution to assessing risks to price stability

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    The long-run relationship between money and prices in the euro area embedded in traditional money demand models with income and interest rates broke down after 2001. We develop a money demand model where investors hold a diversified portfolio with money, domestic and foreign stocks and long-term bonds in which, in addition to the classical wealth effect, also a size and an international portfolio allocation effects arise. The estimated model identifies three cointegrating vectors stable over the sample 1980-2007: a long-run money demand, which depends on income and all risky assets' returns, and two equilibria for the euro area and the US financial markets. Steady state equilibrium of nominal M3 growth is estimated to be about 7% in 2007 with large standard errors mainly due to uncertainty in asset prices. The gap between actual euro area M3 growth and model-based fitted or predicted values helps forecast euro area inflation

    Design of Self-Healing Key Distribution Schemes

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    A self-healing key distribution scheme enables dynamic groups of users of an unreliable network to establish group keys for secure communication. In such a scheme, a group manager, at the beginning of each session, in order to provide a key to each member of the group, sends packets over a broadcast channel. Every user, belonging to the group, computes the group key by using the packets and some private information. The group manager can start multiple sessions during a certain time-interval, by adding/removing users to/from the initial group. The main property of the scheme is that, if during a certain session some broadcasted packet gets lost, then users are still capable of recovering the group key for that session simply by using the packets they have received during a previous session and the packets they will receive at the beginning of a subsequent one, without requesting additional transmission from the group manager. Indeed, the only requirement that must be satisfied, in order for the user to recover the lost keys, is membership in the group both before and after the sessions in which the broadcast messages containing the keys are sent. This novel and appealing approach to key distribution is quite suitable in certain military applications and in several Internet-related settings, where high security requirements need to be satisfied. In this paper we continue the study of self-healing key distribution schemes, introduced by Staddon et al. [37]. We analyze some existing constructions: we show an attack that can be applied to one of these constructions, in order to recover session keys, and two problems in another construction. Then, we present a new mechanism for implementing the self-healing approach, and we present an efficient construction which is optimal in terms of user memory storage. Finally, we extend the self-healing approach to key distribution, and we present a scheme which enables a user to recover from a single broadcast message all keys associated with sessions in which he is member of the communication group

    Asimmetria del rischio sistematico dei titoli immobiliari americani: nuove evidenze econometriche

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    In this work we have found a relevant increase in the systematic risk of the American real estate securities in the year 2007 which go to the initial values in the year 2009. With the aim to evaluate the systematic risk we have used the Fama-French three factor model and we have studied the relationship between the extra-return of the REIT index where we have used as proxy the American real estate securities and the extra return of the S&P500 index representative by the market portfolio return. The results confirmed the presence of an “Asymmetric Beta Puzzle” in agreement with other previous studies. At the same time the results have shown that the REIT securities behaved as speculative securities. In the past the same securities were considered conservative in the year of the subprime crisis. The REIT securities in particular have amplified arriving to double the variations of the market risk premium

    A class of stochastic games with infinitely many interacting agents related to Glauber dynamics on random graphs

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    We introduce and study a class of infinite-horizon nonzero-sum non-cooperative stochastic games with infinitely many interacting agents using ideas of statistical mechanics. First we show, in the general case of asymmetric interactions, the existence of a strategy that allows any player to eliminate losses after a finite random time. In the special case of symmetric interactions, we also prove that, as time goes to infinity, the game converges to a Nash equilibrium. Moreover, assuming that all agents adopt the same strategy, using arguments related to those leading to perfect simulation algorithms, spatial mixing and ergodicity are proved. In turn, ergodicity allows us to prove "fixation", i.e. that players will adopt a constant strategy after a finite time. The resulting dynamics is related to zerotemperature Glauber dynamics on random graphs of possibly infinite volume

    Asimmetria del rischio sistematico dei titoli immobiliari americani: nuove evidenze econometriche

    Get PDF
    In this work we have found a relevant increase in the systematic risk of the American real estate securities in the year 2007 which go to the initial values in the year 2009. With the aim to evaluate the systematic risk we have used the Fama-French three factor model and we have studied the relationship between the extra-return of the REIT index where we have used as proxy the American real estate securities and the extra return of the S&P500 index representative by the market portfolio return. The results confirmed the presence of an “Asymmetric Beta Puzzle” in agreement with other previous studies. At the same time the results have shown that the REIT securities behaved as speculative securities. In the past the same securities were considered conservative in the year of the subprime crisis. The REIT securities in particular have amplified arriving to double the variations of the market risk premium

    A geobotanical survey on acidophilous grasslands in the Abruzzo, Lazio and Molise National Park (Central Italy)

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    The acidophilous grasslands of the south-eastern part of the Abruzzo, Lazio and Molise National Park was studied by the phytosociological method and analyzed from a synecological viewpoint with the help of soil analysis. Four clusters of relevés resulted from the numerical classification. Syntaxonomically they were ascribed to the following associations: Poo violaceae-Nardetum strictae, Potentillo rigoanae-Festucetum paniculatae, Nardo strictae-Brachypodietum genuensis and Potentillo rigoanae-Brachypodietum genuensis. Since the original proposal of all the syntaxa identified in the present study were affected by nomenclatural mistakes, they were corrected in accordance with the rules of ICPN. The occurrence of Anthoxanto-Brachypodietum in central Apennines, is excluded since this association falls in syntaxonomical synonymy with Potentillo-Brachypodietum. The synecological analysis proved that the distribution of the different communities identified within the study area to be correlated with topographic, geomorphological and soil factors. Among these latter, the ratio H+/basic cations, pH behave as the most influencing parameters in the distribution of the communities identified

    Effect of different lignocellulosic fibres on poly(ε-caprolactone)-based composites for potential applications in orthotics

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    This work compares the mechanical and thermal behaviour of fully biodegradable biocomposites based on polycaprolactone reinforced with three different natural fibres, namely hemp, sisal and coir, for potential applications in the field of orthoses. The same properties were further compared to those of two commercially available materials commonly used in the same prospective field. The results confirmed that the addition of natural fibres, irrespective of the origin of the fibres (leaf, bast or fruit) to a biodegradable matrix allows for significant improvement of the mechanical behaviour of the ensuing composites compared to traditional thermoplastic materials used in orthotics

    Microbiological challenge testing for Listeria monocytogenes in ready-to-eat food: a practical approach

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    Food business operators (FBOs) are the primary responsible for the safety of food they place on the market. The definition and validation of the product’s shelf-life is an essential part for ensuring microbiological safety of food and health of consumers. In the frame of the Regulation (EC) No 2073/2005 on microbiological criteria for foodstuffs, FBOs shall conduct shelf-life studies in order to assure that their food does not exceed the food safety criteria throughout the defined shelf-life. In particular this is required for ready-to-eat (RTE) food that supports the growth of Listeria monocytogenes. Among other studies, FBOs can rely on the conclusion drawn by microbiological challenge tests. A microbiological challenge test consists in the artificial contamination of a food with a pathogen microorganism and aims at simulating its behaviour during processing and distribution under the foreseen storage and handling conditions. A number of documents published by international health authorities and research institutions describes how to conduct challenge studies. The authors reviewed the existing literature and described the methodology for implementing such laboratory studies. All the main aspects for the conduction of L. monocytogenes microbiological challenge tests were considered, from the selection of the strains, preparation and choice of the inoculum level and method of contamination, to the experimental design and data interpretation. The objective of the present document is to provide an exhaustive and practical guideline for laboratories that want to implement L. monocytogenes challenge testing on RTE food
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