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Search Results: 1 - 10 of 144462 matches for " F. Ferroni "
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The microcanonical ensemble of the ideal relativistic quantum gas with angular momentum conservation
F. Becattini,L. Ferroni
Physics , 2007, DOI: 10.1140/epjc/s10052-007-0403-7
Abstract: We derive the microcanonical partition function of the ideal relativistic quantum gas with fixed intrinsic angular momentum as an expansion over fixed multiplicities. We developed a group theoretical approach by generalizing known projection techniques to the Poincare' group. Our calculation is carried out in a quantum field framework and applies to particles with any spin. It extends known results in literature in that it does not introduce any large volume approximation and it takes particle spin fully into account. We provide expressions of the microcanonical partition function at fixed multiplicities in the limiting classical case of large volumes and large angular momenta and in the grand-canonical ensemble. We also derive the microcanonical partition function of the ideal relativistic quantum gas with fixed parity.
Statistical hadronization with exclusive channels in e+e- annihilation
L. Ferroni,F. Becattini
Physics , 2011, DOI: 10.1140/epjc/s10052-011-1824-x
Abstract: We perform a systematic analysis of exclusive hadronic channels in e+e- collisions at centre-of-mass energies between 2.1 and 2.6 GeV within the statistical hadronization model. Because of the low multiplicities involved, calculations have been carried out in the full microcanonical ensemble, including conservation of energy-momentum, angular momentum, parity, isospin, and all relevant charges. We show that the data is in an overall good agreement with the model for an energy density of about 0.5 GeV/fm^3 and an extra strangeness suppression parameter gamma_S ~ 0.7, essentially the same values found with fits to inclusive multiplicities at higher energy.
The microcanonical ensemble of the ideal relativistic quantum gas
F. Becattini,L. Ferroni
Physics , 2007, DOI: 10.1140/epjc/s10052-007-0340-5
Abstract: We derive the microcanonical partition function of the ideal relativistic quantum gas of spinless bosons in a quantum field framework as an expansion over fixed multiplicities. Our calculation generalizes well known expressions in literature in that it does not introduce any large volume approximation and it is valid at any volume. We discuss the issues concerned with the definition of the microcanonical ensemble for a free quantum field at volumes comparable with the Compton wavelength and provide a consistent prescription of calculating the microcanonical partition function, which is finite at finite volume and yielding the correct thermodynamic limit. Besides an immaterial overall factor, the obtained expression turns out to be the same as in the non-relativistic multi-particle approach. This work is introductory to derive the most general expression of the microcanonical partition function fixing the maximal set of observables of the Poincare' group.
Multiplicity fluctuations in the hadron gas with exact conservation laws
F. Becattini,A. Keranen,L. Ferroni,T. Gabbriellini
Physics , 2005, DOI: 10.1103/PhysRevC.72.064904
Abstract: The study of fluctuations of particle multiplicities in relativistic heavy-ion reactions has drawn much attention in recent years, because they have been proposed as a probe for underlying dynamics and possible formation of quark-gluon plasma. Thus, it is of uttermost importance to describe the baseline of statistical fluctuations in the hadron gas phase in a correct way. We have performed a comprehensive study of multiplicity distributions in the full ideal hadron-resonance gas in different ensembles, namely grand-canonical, canonical and microcanonical, using two different methods: asymptotic expansions and full Monte Carlo simulations. The method based on asymptotic expansion allows a quick numerical calculation of dispersions in the hadron gas with three conserved charges at primary hadron level, while the Monte-Carlo simulation is suitable to study the effect of resonance decays. Even though mean multiplicities converge to the same values, major differences in fluctuations for these ensembles persist in the thermodynamic limit, as pointed out in recent studies. We observe that this difference is ultimately related to the non-additivity of the variances in the ensembles with exact conservation of extensive quantities.
Commentary on MEDEA: A DSGE model for the Spanish economy
Filippo Ferroni
SERIEs , 2010, DOI: 10.1007/s13209-009-0012-9
Estratégias utilizadas por aprendizes de línguas afins: a troca de código Strategies employed by learners of related languages: code-switching
Roberta Ferroni
Trabalhos em Linguística Aplicada , 2012, DOI: 10.1590/s0103-18132012000200004
Abstract: Neste artigo analisamos a troca de código, uma estratégia de compensa o que consiste na utiliza o de uma palavra ou frase em L1, L3 ou L4, no interior do enunciado em L2, empregada por aprendizes de italiano LE cuja língua materna é o português brasileiro, durante a realiza o em dupla de uma tarefa escrita. A pesquisa, que se baseou nos instrumentos propostos pela etnografia, mostra que a troca de código constitui um potencial para o desenvolvimento da interlíngua e para a aquisi o/aprendizagem de LE e que tal estratégia, além de compensar eventuais lacunas linguísticas originadas pela falta de recursos adequados para expressar-se em LE, é usada pelos falantes como procedimento típico da conversa o bilíngue para facilitar a comunica o. In this paper we examine code-switching, an achievement strategy consisting in the use of a word or phrase from L1, L3 or L4 within an utterance in L2, as employed by learners of Italian as a foreign language who have Brazilian Portuguese as their mother tongue, while performing a written task in pairs. The research, based on tools provided by an ethnographic approach, shows that code-switching constitutes a potential for developing interlanguage and for the acquisition/learning of a foreign language and that such strategy, in addition to compensating eventual linguistic gaps originated by a lack of proper resources for expression in L2, is used by speakers as a typical procedure in bilingual conversation, in order to facilitate the communication.
Threshold effects in relativistic gases
V. V. Begun,L. Ferroni,M. I. Gorenstein,M. Gazdzicki,F. Becattini
Physics , 2005, DOI: 10.1088/0954-3899/32/7/009
Abstract: Particle multiplicities and ratios in the microcanonical ensemble of relativistic gases near production thresholds are studied. It is shown that the ratio of heavy to light particle multiplicity may be enhanced in comparison to its thermodynamic limit.
Investigating The Physics Case of Running a B-Factory at the Y(5S) Resonance
Baracchini, E.;Bona, M.;Ciuchini, M.;Ferroni, F.;Pierini, M.;Piredda, G.;Renga, F.;Silvestrini, L.;Stocchi, A.
High Energy Physics - Phenomenology , 2007, DOI: 10.1088/1126-6708/2007/08/005
Abstract: We discuss the physics case of a high luminosity B-Factory running at the Y(5S) resonance. We show that the coherence of the B meson pairs is preserved at this resonance, and that Bs can be well distinguished from Bd and charged B mesons. These facts allow to cover the physics program of a traditional B-Factory and, at the same time, to perform complementary measurements which are not accessible at the Y(4S). In particular we show how, despite the experimental limitations in performing time-dependent measurements of Bs decays, the same experimental information can be extracted, in several cases, from the determination of time-integrated observables. In addition, a few examples of the potentiality in measuring rare Bs decays are given. Finally, we discuss how the study of Bs meson will improve the constraints on New Physics parameters in the Bs sector, in the context of the generalized Unitarity Triangle analysis.
Public-Private Partnerships and Sustainable Agricultural Development
Marco Ferroni,Paul Castle
Sustainability , 2011, DOI: 10.3390/su3071064
Abstract: Agriculture in Africa is not sustainable because average yields have been stagnating for decades due to underinvestment, especially in the development of agricultural markets, crop improvement and the sustainable management of agricultural systems. Low public sector funding for agricultural research and lack of incentives for the private sector to operate in areas where there is no market largely explain the yield gap in many food-importing developing countries. Yet, there are effective ways in which the public and the private sector could work together and jointly improve agricultural sustainability in poor countries. The public sector provides a favorable institutional environment for the development of agricultural markets and investment in rural infrastructure, facilitates local business development and funds research with local relevance. The private sector, in return, brings its considerable expertise in product development and deployment. This article illustrates how new forms of public-private partnerships (PPPs) for agricultural development can work in challenging environments. It discusses three promising examples of PPPs in which the Syngenta Foundation for Sustainable Agriculture (SFSA) is actively involved, and shows that an experimental approach can sometimes be more effective than social planning in efforts to achieve sustainable agriculture.
Predictors of letter knowledge in children growing in poverty
Diuk, Beatriz;Ferroni, Marina;
Psicologia: Reflex?o e Crítica , 2011, DOI: 10.1590/S0102-79722011000300018
Abstract: this study examined the influence of phonological processing abilities on letter knowledge and letter learning in 1st grade children growing in poverty. at the beginning of the school year, 59 first graders were evaluated with tests measuring phonological awareness, phonological memory and rapid naming. letter knowledge was assessed at the beginning and at the end of the year. all phonological processing abilities predicted letter knowledge at time 1, with phonological awareness producing the largest effect. however, only phonological memory predicted additional letter learning during the school year, once initial letter knowledge was taken into account.
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