5,600 research outputs found
La Galleria su piazza Colonna: un'architettura per immagini/The Galleria on Piazza Colonna: the Building through Images
No full textStoria e analisi critica del progetto della Galleria Coperta su piazza Colonna, opera dell'architetto D. CarboneHistory and critical analysis of the project's Blanket Gallery on the Piazza Colonna, the work of D. Coa
Piazza Navona. Une anthropologie au présent
No full textConduire une ethnologie de la Piazza Navona aujourd’hui revient à interroger la relation entre les formes spatiales et les comportements sociaux dont quelques grands architectes contemporains ont parfois rapidement supposé que les seconds découlent directement des premières. L’enquête ethnographique souligne que cette détermination est très indirecte et, surtout, qu’elle dépend avant tout de l’histoire telle qu’elle est vécue et telle qu’elle est représentée. Aujourd’hui la Piazza Navona est, pour une part, un non-lieu, un espace neutre de circulation et de transaction commerciale, l’une et l’autre liées au trafic touristique. Mais cette vision générale, étayée par l’approche historique des transformations de l’espace social du rione, ignore trois phénomènes importants qui restituent à la place la complexité et la richesse d’un lieu, au sens plein du terme, habitable collectivement. Le premier, porté par les derniers témoins d’un « âge d’or » des années 1960, repose sur la mémoire nostalgique. Le second souligne la temporalité particulière – circadienne autant que calendaire – qui fait de la place un espace rythmé et, à ce titre, disputé. Le troisième montre qu’à distance des places centrales du pouvoir et du contre-pouvoir de masse, la Piazza Navona est devenue aussi une scène très particulière de l’expression politique
Variational measures in the theory of integration
No full text{Variational measures in the theory of integration}
{Luisa Di Piazza}
{Palermo , Italy}
We will present here some results concerning the variational measures associated to a real valued function, or, in a more general setting, to a vector valued function. Roughly speaking, given a function defined on an interval of the real line it is possible to construct, using suitable families of intervals, a measure which carries information about . If is a real valued function, then the -finiteness of the measure implies the a.e. differentiability of , while the absolute continuity of the measure characterizes the functions which are Henstock-Kurzweil primitives. The situation becomes more complicate if we consider functions taking values in an infinite dimensional Banach space. If the Banach space has the Radon-Nikod\'{y}m property, then it is possible to obtain properties similar to those of the real case. But it is surprising that by means of the variational measures it is possible to characterize the Banach space having the Radon-Nikod\'{y}m property.
\begin{thebibliography}{99}
\bibitem{bds1} B. Bongiorno, L. Di Piazza and V. Skvortsov,
\textit{ A new full descriptive characterization of Denjoy-Perron
integral}, Real Analysis Exchange, {\bf 21} (1995/96), 256--263.
\bibitem{bdm} B. Bongiorno, L. Di Piazza and K. Musial,
\textit{ A characterization of the
Radon-Nikod\'{y}m property by finitely additive interval
functions}, Illinois Journal of Mathematics. Volume 53, Number 1 (2009), 87-99.
\bibitem{db} D. Bongiorno, \textit{ Stepanoff's theorem in separable Banach
spaces}, Comment. Math. Univ. Ca\-ro\-linae, {\bf 39} (1998),
323--335.
\bibitem{ldp1} L. Di Piazza, \textit{ Varational measures in the theory of the
integration in }, Czechos. Math. Jour. 51(126) (2001), no. 1,
95--110.
\bibitem{vm} V. Marraffa, \textit{
A descriptive characterization of the
variational Henstock integral}, Proceedings of the International
Mathematics Conference (Manila, 1998), Matimy\'{a}s Mat. {\bf 22}
(1999), no. 2, 73--84
MR2741185 Talvila, Erik The regulated primitive integral. Illinois J. Math. 53 (2009), no. 4, 1187–1219. (Reviewer: Luisa Di Piazza) 46G12 (26A39 46E15 46F10)
No full textTalvila Erik, The regulated primitive integral. Illinois J. Math. 53 (2009), no. 4, 1187–1219, 46Gxx (26A39 46Exx) MR 2 741 185
A descriptive definition of an integral is a definition which provides a ``description'' of the space of primitives. The derivatives in some sense of the primitives are the integrands.
In this paper the author introduces a descriptive method of integrating distributions: the regulated primitive integral.
The set \textbf{B}_R= \{F: [-\infty,\infty]
\rightarrow {\bf R}
\ \ | \mbox{ F {\it is regulated and left continuous on }}\\
\ \ {\bf R},
\ \ F(-\infty)=0, \ \ F(\infty)\in {\bf R}\} is the family of primitives.
The derivative here is in the sense of the distributions (i.e. a distributional or weak derivative). Then the integrable distributions are those distributions (in the Schwartz's sense) that are the distributional derivative of a function in .
The regulated primitive integral is a proper extension of the integral of distribution defined by L. Schwartz [Théorie des distributions. (French) Publications de l'Institut de Mathématique de l'Université de Strasbourg, No. IX-X. Hermann, Paris 1966 xiii+420, 46.40 (44.00), MR0209834 (35730)]. Moreover it is proved that the space of regulated integrable distributions is the completion of the space of signed Radon measures in the Alexiewicz norm, but it is not the completion in this norm of the Henstock-Kurzweil integrable functions. The functions of bounded variation constitute its dual space and also the space of multipliers. In the introduction a wide
panorama of descriptive and constructive integration methods is given.
Reviewed by (L. Di Piazza
MR2657294 (2011h:28021) Bensimhoun, Michael Change of variable theorems for the KH integral. Real Anal. Exchange 35 (2010), no. 1, 167–194. (Reviewer: Luisa Di Piazza), 28B05 (26A42 46G10)
No full textFrom Reviews: 0
MR2657294 (2011h:28021)
Bensimhoun, Michael(IL-HEBR)
Change of variable theorems for the KH integral. (English summary)
Real Anal. Exchange 35 (2010), no. 1, 167–194.
28B05 (26A42 46G10)
PDF Clipboard Journal Article Make Link
Let ({\scr E},{\scr F}, {\scr G})(E,F,G) be a Banach triple and let f\colon [a,b] \subset \overline{\Bbb R} \rightarrow {\scr E}f:[a,b]⊂R−−→E, \varphi \colon [a,b] \rightarrow {\scr F}φ:[a,b]→F and ψ:[c,d]⊂R−−→[a,b] be given. The problem of change of variables in an integral consists in finding the best conditions under which the equality ∫dcf∘ψ⋅d(φ∘ψ)=∫ψ(d)ψ(c)f⋅dφ(1) holds, when one of these two integrals exists.
Here the context is that of the Kurzweil-Henstock-Stieltjes integral. The main result is Theorem 6.1:
Assume that ψ is continuous. If f∘ψ⋅d(φ∘ψ) is integrable in [c,d], then f⋅dφ is integrable in ψ([c,d]) and equality (1) holds.
Furthermore, if f∘ψ⋅d(φ∘ψ) is absolutely integrable in [c,d], then f⋅dφ is absolutely integrable in ψ([c,d]), with ∫dc∥f∘ψ⋅d(φ∘ψ)∥=∫ψ(d)ψ(c)∥f⋅dφ∥.
Without very specific additional conditions on f, the continuity of ψ is essential in order to get relation (1). As a corollary of Theorem 6.1, the author obtains, with an alternative proof, a formula for change of variables in [S. Leader, Real Anal. Exchange 29 (2003/04), no. 2, 905--920; MR2083825 (2005f:26023)], for the case φ=Id and ψ real-valued of bounded variation.
In the second part of the paper, necessary and sufficient conditions are given in order that the integrability of f⋅dφ implies that of f∘ψ⋅d(φ∘ψ) and the change of variable formula.
Reviewed by Luisa Di Piazz
The effects of hydroxyethyl starch solution in critically ill patients.
No full textPalumbo D, Servillo G, D'Amato L, Volpe ML, Capogrosso G, De Robertis E,
Piazza O, Tufano R.
The effects of hydroxyethyl starch solution in critically ill patients.
Minerva Anestesiol. 2006 Jul-Aug;72(7-8):655-6
MR2684422 Deville, Robert; Rodríguez, José Integration in Hilbert generated Banach spaces. Israel J. Math. 177 (2010), 285–306. (Reviewer: Luisa Di Piazza)
No full text2010), 285–306, 46Exx (46J10)
It is known that each McShane integrable function is also Pettis integrable, while the reverse implication in general is not true.
The equivalence of McShane and Pettis integrability depends on
the target Banach space X and has been proven: by R. A. Gordon [Illinois J. Math. 34 (1990), no. 3, 557–567, 26A42 (28B15 46G10 49Q15)], and by D. H. Fremlin and J. Mendoza [Illinois J. Math. 38 (1994), no. 1, 127–147, 46G10 (28B05)] if X is separable, by D. Preiss and the reviewer [Illinois J. Math. 47 (2003), no. 4, 1177–1187. 28B05 (26A39 26E25 46G10)] if X=c_0(\Gamma) (for any set
\Gamma) or X is super-reflexive, by the second author of the present paper [J. Math. Anal. Appl. 341 (2008), no. 1, 80–90, 46G10 (28B05 46B99 47B10)] if X=L^1(\nu) (for any probability measure
\nu).
Here the authors show that the McShane and Pettis integrability coincide for functions taking values in a subspace of a Hilbert generated Banach space. This result includes all previous known ones concerning the above mentioned equivalence.
The used approach relies heavily on some special properties of the Markushevich bases of those Banach spaces. They also give a ZFC example of a scalarly negligible function which is not McShane integrable.
Moreover they prove that, whenever the target Banach space is super-reflexive generated, the Birkhoff integrability lies strictly between Bochner and McShane integrability. Reviewed by L. Di Piazz
An analytical model of heat transfer and fluid dynamic performances of an unconventional NTR engine for manned interplanetary missions
No full textAn analytical model of fluid flow and heat transfer of a Nuclear Thermal Rocket (NTR) engine concept is
presented. The engine is based on the direct conversion of the kinetic energy of the fission fragments (FFs)
into the propellant enthalpy. The FFs can escape from an extremely thin layer of fissionable material:
a sufficiently large surface coated with few micrometers of Americium 242m, confined by a neutron
moderator–reflector, may become a critical reactor.
Three dimensional coupled CFD-Monte Carlo simulations have already been presented in Di Piazza
and Mulas (2006). In this paper, an analytical integral 1-D model of fluid dynamics and heat transfer is
built in order to foresee the performances on the basis of simple, physically founded correlations. The
Peclet number has been identified as the main governing parameter of the system, and theoretically based
correlations have been found for the thermodynamic efficiency of the engine and for the specific impulse.
The correlations show a good agreement with numerical results presented in Di Piazza and Mulas (2006)
from fully coupled 3D CFD-Monte Carlo calculations
Il cantiere nel Settecento
No full textIl contributo analizza e approfondisce la vicenda progettuale e costruttiva relativa ai differenti interventi settecenteschi della chiesa di San Domenico a Palermo(l'attribuzione del progetto della facciata e il suo completamento,i progetti per i campanili, per la piazza dell'Immacolata, e per gli altari interni),fornendo chiarimenti rispetto agli studi precedenti, specificando la corretta cronologia e i progettisti, oltre che le dinamiche di cantiere e i riferimenti formali e relazionando questi ultimi alla coeva produzione italiana ed europea
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