Formality and Star Products

These notes, based on the mini-course given at the PQR2003 Euroschool held in Brussels in 2003, aim to review Kontsevich's formality theorem together with his formula for the star product on a given Poisson manifold. A brief introduction to the employed mathematical tools and physical motivations is also given.Comment: 49 pages, 9 figures; proceedings of the PQR2003 Euroschool. Version 2 has minor correction

HIPK2 deficiency causes chromosomal instability by cytokinesis failure and increases tumorigenicity

HIPK2, a cell fate decision kinase inactivated in several human cancers, is thought to exert its oncosuppressing activity through its p53-dependent and -independent apoptotic function. However, a HIPK2 role in cell proliferation has also been described. In particular, HIPK2 is required to complete cytokinesis and impaired HIPK2 expression results in cytokinesis failure and tetraploidization. Since tetraploidy may yield to aneuploidy and chromosomal instability (CIN), we asked whether unscheduled tetraploidy caused by loss of HIPK2 might contribute to tumorigenicity. Here, we show that, compared to Hipk2+/+ mouse embryo fibroblasts (MEFs), hipk2-null MEFs accumulate subtetraploid karyotypes and develop CIN. Accumulation of these defects inhibits proliferation and spontaneous immortalization of primary MEFs whereas increases tumorigenicity when MEFs are transformed by E1A and Harvey-Ras oncogenes. Upon mouse injection, E1A/Ras-transformed hipk2-null MEFs generate tumors with genetic alterations resembling those of human cancers derived by initial tetraploidization events, such as pancreatic adenocarcinoma. Thus, we evaluated HIPK2 expression in different stages of pancreatic transformation. Importantly, we found a significant correlation among reduced HIPK2 expression, high grade of malignancy, and high nuclear size, a marker of increased ploidy. Overall, these results indicate that HIPK2 acts as a caretaker gene, whose inactivation increases tumorigenicity and causes CIN by cytokinesis failure

Theoretical and numerical modeling of multicomponent transcritical diffuses interfaces

In this study, we present a theoretical and numerical framework for simulating transcritical flows under a variety of conditions of interest for aerospace applications. A real multi-component and multi-phase thermodynamic model, based on a cubic equation of state and vapor-liquid equilibrium assumptions, is used to describe transcritical mixtures. The versatility of this model is reported since it can represent at the same time the supercritical states and subcritical stable two-phase states at equilibrium. We emphasize the difference in the mixing behaviors conducted with and without the VLE assumptions. The well-known numerical challenges that arise with the coupling between thermodynamics and governing equations under transcritical conditions are addressed by comparing a fully conservative to a quasi-conservative scheme in the context of density-based solvers while discussing the possibility of employing a pressure-based approach given the typically low-Mach number at play for the cases of interest

Conservation techniques and valorization strategies for rock-cut architecture

Innovative methods for knowledge, diagnostics and communication of buildings and artifacts, combined with traditional processes of historical investigation, have been the instrument through which draw up a proposal for the conservation, the real and virtual fruition and the valorization of the necropolis of Realmese in Calascibetta (Enna, Italy). In 1949, this settlement was unearthed, but despite some actions carried out for its safeguarding and for improving its accessibility, it has not yet received the right attention and appreciation. This study has allowed reflecting both upon new approaches to the issue of the restoration and promotion of rock-cut sites and, at the same time, the possibilities of protection and valorization of the delicate archaeological grave goods there discovered. The main purpose is that of understanding the complexity of this particular architectural natural and human site, its cultural peculiarities and criticalities, in order to establish the most appropriate solutions for its survival

La Villa Romana del Casale di Piazza Armerina: il ruolo del rilievo nell’evoluzione dei processi di conoscenza e comunicazione di un sito culturale di eccezione

This paper intends to highlight the importance of knowledge in cultural heritage conservation and valorization. In particular, World Heritage sites are outstanding example among the countless testimonies of the past and may constitute a source of inspiration for building or strengthening the sense of identity of local communities of which they are a concrete manifestation. Based on some experiences conducted on both the Villa Romana del Casale and the historic center of Piazza Armerina, this work focuses on the role of survey, seen as a valuable tool for the understanding and transmission to future generations of genius loci

Il complesso solfifero di Floristella-Grottacalda. Conoscenza, comprensione e comunicazione del paesaggio industriale dismesso del sito minerario di Floristella-Grottacalda

L’estensione del concetto di patrimonio culturale anche all’ambiente urbano e al paesaggio ha portato ad intensificare l’attenzione verso tematiche e oggetti prima assolutamente trascurati. Alla tradizionale definizione di monumento, oggi si affianca infatti anche la nuova idea di monumento industriale, resto fisico del fenomeno produttivo e oggetto della civiltà materiale che lo ha prodotto. Tale acquisizione concettuale, frutto della consapevolezza che anche gli oggetti della produzione industriale e il contesto ambientale entro cui sono inseriti costituiscono valore culturale, ci porta ad avere una visione molto più complessa dell’ambito all’interno del quale si manifestano le diverse realtà costruite storiche. La pubblicazione del Landscape character assessment. Guidance for England and Scotlandl ha portato alla codifica degli elementi che inducono alla riflessione sull’idea di paesaggio, includendo come fattore discriminante quello della percezione umana dell’ambiente. Se, infatti, il concetto di territorio denota una porzione definita della Terra con caratteristiche di tipo morfologico, ambientale, geografico, amministrativo, il concetto di paesaggio coinvolge una molteplicità di aspetti: naturali, antropici e, appunto, soggettivo - percettivi. Dall’inclusione della percezione umana scaturisce l’idea secondo cui il paesaggio è un costrutto culturale, risultato dell’interpretazione del territorio da parte di chi lo osserva, lo studia, lo vive e lo rappresenta. Nello specifico, il paesaggio industriale è dunque la forma che l’uomo nel corso e ai fini delle sue attività agricole ed industriali coscientemente e sistematicamente imprime al paesaggio naturale o agricolo. L’indagine archivistico-bibliografica, unita al rilievo e alla rappresentazione grafica degli elementi che compongono il sistema solfifero di Floristella-Grottacalda nel territorio di Enna, è stata finalizzata alla conoscenza e alla valorizzazione del patrimonio culturale, archeologico industriale e paesaggistico ambientale con lo scopo di preservare la conoscenza e la memoria di una delle fasi di maggiore sviluppo della civiltà locale, incitando a preservarne le testimonianze essenziali, in un periodo post-industriale tendenzialmente poco favorevole alla loro conservazione

Misura e proporzione: nuove indagini per la conoscenza e la comprensione della Chiesa dei Santi Bartolomeo e Stefano a Bergamo

La fondazione della Chiesa dei Santi Bartolomeo e Stefano, nuova sede dei frati domenicani a Bergamo, risale alla fine del XVI secolo. Il progetto si deve ad Antonio Maria Caneva, figura colta ed eclettica, valido conoscitore delle regole del rapporto aureo ed esperto nell’uso della prospettiva, cui è forse da attribuire la volontà di legare il disegno della fabbrica ad un rigoroso rispetto dei rapporti e delle proporzioni. Nuove attività di ricognizione mensoria e di indagine diagnostica, operate sia con le tradizionali metodologie dirette sia con il 3D laser scanning, hanno mirato a colmare la carenza di documentazione e ad avviare un processo interpretativo utile a migliorare la conoscenza geometrica dell’edificio, anche al fine di predisporre gli ormai urgenti interventi di conservazione e consolidamento

Morpho-architectural analysis, constructive modalities and structural diagnostics for the restoration of the Church of SS Bartholomew and Stephen in Bergamo

Today, the final purpose of historical buildings’ conservation seems having lost importance in the common consciousness, to lead at times to the point of not remember the reason for undertaking such activities. As a result, the instruments offered by technological progress are often undervalued in terms of the beneficial contribution that they can provide to the comprehension, preservation and enhancement of architecture. In the case study of the Church of SS Bartholomew and Stephen in Bergamo, 3D laser scanning combined with traditional techniques of investigation and diagnosis has allowed achieving a new monument’s awareness, under the morphological and constructive point of views. In particular, it has helped the understanding of the precarious conditions of stability of the roofing. In addition to a widespread state of degradation and failure of some timber elements, the roof presents problems related to the linking between the individual components of the first and second array, the connections and support on the pillars and to the backing to the perimeter masonry cornices. Multi-levels analysis facilitated the comprehension of the overall behavior of coverage structure as well as of other technical parts, in order to prefigure timely restoration of the wooden elements. Finally yet importantly, they highlighted exceptional architectural and decorative characteristics, which are already, themselves, cultural values that deserve protection and transmission to future generation

Keeping the Equilibrium: The Static Aspects of the Restoration Project: The Case Study of the Mother Church of San Cataldo (Sicily)

The Mother Church of San Cataldo (Sicily) has always been affected by structural problems, today still evident. Established in an area characterized by a geological heterogeneity it was over time subjected to restoration work that caused additional weakness. The study carried by the authors of this paper has allowed experimentally use 3D laser scanning to support the analysis of decays and structural damages of this monumental masonry construction, combined and integrated with the essential historical research and the visual observation. The precise identification of building diseases and especially of the causes that determine their occurrence is an inevitable prerequisite for the definition of restoration work targeted and mutually cooperating to the preservation of cultural heritage for the sake of future generations

A historico-critical analysis for the conservation and rehabilitation of Bourbon prison in Syracuse

An imposing building interrupts the dense Arab fabric of Graziella district on the island of Ortigia (Syracuse): the seat of the former Bourbon prison. Bentham’s Panopticon inspired its shape, but the final form was somewhat altered by local customs, in accordance with Bourbon reforms. As learned from archival and unpublished sources and following detailed geometric and material surveys carried out by integrating traditional and innovative techniques, in the center of the courtyard, a Panoptic chapel was designed for religious purposes. The prisoners could so participate in the sacred ceremonies that were hypothesized to facilitate their repentance and social rehabilitation. Based on the study of morphological and systemconstruction evolution, this work aims at highlighting the building’s important historical significance. It also intends to formulate a proposal for a new function, which sees in the creation of a "museum of prisons and Bourbon domination in Sicily" a way of cultural promotion