516 research outputs found
Epifani nella prima fase del regionalismo italiano
No full textPremessi brevi cenni sulla distinzione tra i concetti di federalismo e di regionalismo, il contributo indaga il pensiero e l'opera di Vito Donato Epifani, sostenitore dell'idea regionale nella seconda metà del XIX secolo e precursore del principio di sussidiarietà
Means of nonparametric priors based on Increasing Additive Processes
No full textWe provide a survey on some distributional results concerning means of random probability measure constructed via suitable transformation of an increasing additive process (abbreviated as IAP), i.e. increasing, not necessarily hopmogeneous, and purely discontinuous Lévy process. In particular, we deal with normalized random measures having independent increments and with neutral to the right (NTR) random probability measures. The former are obtained by normalizing IAPs and the exact distribution of a mean is found by resorting to a well-known inversion formula for characteristic functions. Morevoer, expressions of the posterior distributions of those means, in the presence of exchangeable observations, are given. Also the latter may be characterized in terms of IAPs and we show the connection between a mean of a NTR prior and the so-called exponential functional. We study finiteness and absolute continuity of these functionals and provide some formulae for computing their moments, provided they exist. All the results contained in the first section can be found in Lijoi, Regazzini and Pruenster (2000) whereas those of Section 2 are based on Epifani, Lijoi and Pruenster (2002)
Casa Epifani de Fortuny i Farmàcia Grau i Mas
No full textPrimeríssim primer pla de la Casa Epifani de Fortuny i Farmàcia Grau Mas. Fou construïda durant el segon terç del segle XIX. Es situa al carrer del Carme, 23
Some considerations on a version of the Law of the Iterated Logarithm due to F.P. Cantelli
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Nonparametric Priors for Vectors of Survival Functions
Get PDFThe paper proposes a new nonparametric prior for twodimensional vectors of survival functions (S1, S2). The definition we introduce is based on the notion of L´evy copula and it will be used to model, in a nonparametric Bayesian framework, twosample survival data. Such an application will yield a natural extension of the more familiar neutral to the right process of Doksum (1974) adopted for drawing inferences on single survival functions. We, then, obtain a description of the posterior distribution of (S1, S2), conditionally on possibly rightcensored data. As a byproduct of our analysis, we find out that the marginal distribution of a pair of observations from the two samples coincides with the MarshallOlkin or the Weibull distribution according to specific choices of the marginal L´evy measures
A finitely additive version of the law of the iterated logarithm
No full textA finitely additive version of the law of the iterated logarithm (LIL) is proposed. The formulation involves only finite-dimensional distributions of a sequence of independent random variables. It is also proved that in the case where one deals with σ-additive probabilities, the given result is equivalent to the classical version of the LIL
Prime segnalazioni di resti di tacchino in Italia
Get PDFI resti di tacchino (Meleagris gallopavo L.) rinvenuti nei livelli di XVII secolo dello scavo dell’area del Nuovo Mercato Testaccio a Roma, sono tra i primi rinvenuti in un contesto archeologico italiano. I dati raccolti, correlati ad una ricca documentazione scritta e iconografica, permettono di ricostruire le tappe di diffusione del tacchino in Europa. La specie, importata dall’America in Spagna, come attesta un ordine reale del 3 settembre dello stesso anno, giunge in Italia nel 1520. Di seguito compare in Francia in un documento datato al 1534 e, nel 1560, in Germania. A metà del XVI secolo il tacchino si diffonde in Norvegia, Danimarca e Svezia. Per quanto riguarda l’Italia se ne trova testimonianza nell’affresco di villa Medici a Trinità dei Monti a Roma, realizzato da Jacopo Zucchi tra il 1576 e il 1577. Un tacchino è inoltre affrescato sulla volta del loggiato settentrionale di Palazzo Altemps a Roma, opera che Antonio Viviani realizzò tra il 1592 e il 1595, mentre ancora più antico è il tacchino in bronzo del Giambologna, che fu realizzato dall’artista fiammingo nel 1564 per decorare la grotta degli animali della villa medicea di Castello a Firenze
A note on the simulation of Lévy processes with a view towards applications
No full textIn recent years several techniques for simulating purely discontinuous Lévy processes have been developed. Due to the "infinite activity" character of most Lévy processes the achievement of satisfactory approximations is not a trivial issue. By means of two examples, one related to an optimal storage problem and the other to Bayesian nonparametric inference, the behavior of the so-called inverse Lévy measure algorithm is studied. Some hints for overcoming possible difficulties are given
Exponential functionals and means of neutral-to-the-right priors
No full textThe mean of a random distribution chosen from a neutral to-the-right prior can be represented as the exponential functional of an increasing additive process. This fact is exploited in order to give sufficient conditions for the existence of the mean of a neutral to-the-right prior and for the absolute continuity of its probability distribution. Moreover, expressions for its moments, of any order, are provided. For illustrative purposes we consider a generalisation of the neutral-to-the-right prior based on the gamma process and the beta-Stacy process. Finally, by resorting to the maximum entropy algorithm, we obtain an approximation to the probability density function of the mean of a neutral to-the- right prior. The arguments are easily extended to examine means of posterior quantities. The numerical results obtained are compared to those yielded by the application of some well-established simulation algorithms
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