Management and routing algorithms for ad-hoc and sensor networks

Large scale wireless adhoc networks of computers, sensors, PDAs etc. (i.e. nodes) are revolutionizing connectivity and leading to a paradigm shift from centralized systems to highly distributed and dynamic environments. An example of adhoc networks are sensor networks, which are usually composed by small units able to sense and transmit to a sink elementary data which are successively processed by an external machine. Recent improvements in the memory and computational power of sensors, together with the reduction of energy consumptions, are rapidly changing the potential of such systems, moving the attention towards datacentric sensor networks. A plethora of routing and data management algorithms have been proposed for the network path discovery ranging from broadcasting/floodingbased approaches to those using global positioning systems (GPS). We studied WGrid, a novel decentralized infrastructure that organizes wireless devices in an adhoc manner, where each node has one or more virtual coordinates through which both message routing and data management occur without reliance on either flooding/broadcasting operations or GPS. The resulting adhoc network does not suffer from the deadend problem, which happens in geographicbased routing when a node is unable to locate a neighbor closer to the destination than itself. WGrid allow multidimensional data management capability since nodes' virtual coordinates can act as a distributed database without needing neither special implementation or reorganization. Any kind of data (both single and multidimensional) can be distributed, stored and managed. We will show how a location service can be easily implemented so that any search is reduced to a simple query, like for any other data type. WGrid has then been extended by adopting a replication methodology. We called the resulting algorithm WRGrid. Just like WGrid, WRGrid acts as a distributed database without needing neither special implementation nor reorganization and any kind of data can be distributed, stored and managed. We have evaluated the benefits of replication on data management, finding out, from experimental results, that it can halve the average number of hops in the network. The direct consequence of this fact are a significant improvement on energy consumption and a workload balancing among sensors (number of messages routed by each node). Finally, thanks to the replications, whose number can be arbitrarily chosen, the resulting sensor network can face sensors disconnections/connections, due to failures of sensors, without data loss. Another extension to {WGrid} is {W*Grid} which extends it by strongly improving network recovery performance from link and/or device failures that may happen due to crashes or battery exhaustion of devices or to temporary obstacles. W*Grid guarantees, by construction, at least two disjoint paths between each couple of nodes. This implies that the recovery in W*Grid occurs without broadcasting transmissions and guaranteeing robustness while drastically reducing the energy consumption. An extensive number of simulations shows the efficiency, robustness and traffic road of resulting networks under several scenarios of device density and of number of coordinates. Performance analysis have been compared to existent algorithms in order to validate the results.

Studio molecolare dei meccanismi dell'autoincompatibilità gametofitica in pero europeo (Pyrus communis)

Self-incompatibility (SI) systems have evolved in many flowering plants to prevent self-fertilization and thus promote outbreeding. Pear and apple, as many of the species belonging to the Rosaceae, exhibit RNase-mediated gametophytic self-incompatibility, a widespread system carried also by the Solanaceae and Plantaginaceae. Pear orchards must for this reason contain at least two different cultivars that pollenize each other; to guarantee an efficient cross-pollination, they should have overlapping flowering periods and must be genetically compatible. This compatibility is determined by the S-locus, containing at least two genes encoding for a female (pistil) and a male (pollen) determinant. The female determinant in the Rosaceae, Solanaceae and Plantaginaceae system is a stylar glycoprotein with ribonuclease activity (S-RNase), that acts as a specific cytotoxin in incompatible pollen tubes degrading cellular RNAs. Since its identification, the S-RNase gene has been intensively studied and the sequences of a large number of alleles are available in online databases. On the contrary, the male determinant has been only recently identified as a pollen-expressed protein containing a F-box motif, called S-Locus F-box (abbreviated SLF or SFB). Since F-box proteins are best known for their participation to the SCF (Skp1 - Cullin - F-box) E3 ubiquitine ligase enzymatic complex, that is involved in protein degradation through the 26S proteasome pathway, the male determinant is supposed to act mediating the ubiquitination of the S-RNases, targeting them for the degradation in compatible pollen tubes. Attempts to clone SLF/SFB genes in the Pyrinae produced no results until very recently; in apple, the use of genomic libraries allowed the detection of two F-box genes linked to each S haplotype, called SFBB (S-locus F-Box Brothers). In Japanese pear, three SFBB genes linked to each haplotype were cloned from pollen cDNA. The SFBB genes exhibit S haplotype-specific sequence divergence and pollen-specific expression; their multiplicity is a feature whose interpretation is unclear: it has been hypothesized that all of them participate in the S-specific interaction with the RNase, but it is also possible that only one of them is involved in this function. Moreover, even if the S locus male and female determinants are the only responsible for the specificity of the pollen-pistil recognition, many other factors are supposed to play a role in GSI; these are not linked to the S locus and act in a S-haplotype independent manner. They can have a function in regulating the expression of S determinants (group 1 factors), modulating their activity (group 2) or acting downstream, in the accomplishment of the reaction of acceptance or rejection of the pollen tube (group 3). This study was aimed to the elucidation of the molecular mechanism of GSI in European pear (Pyrus communis) as well as in the other Pyrinae; it was divided in two parts, the first focusing on the characterization of male determinants, and the second on factors external to the S locus. The research of S locus F-box genes was primarily aimed to the identification of such genes in European pear, for which sequence data are still not available; moreover, it allowed also to investigate about the S locus structure in the Pyrinae. The analysis was carried out on a pool of varieties of the three species Pyrus communis (European pear), Pyrus pyrifolia (Japanese pear), and Malus × domestica (apple); varieties carrying S haplotypes whose RNases are highly similar were chosen, in order to check whether or not the same level of similarity is maintained also between the male determinants. A total of 82 sequences was obtained, 47 of which represent the first S-locus F-box genes sequenced from European pear. The sequence data strongly support the hypothesis that the S locus structure is conserved among the three species, and presumably among all the Pyrinae; at least five genes have homologs in the analysed S haplotypes, but the number of F-box genes surrounding the S-RNase could be even greater. The high level of sequence divergence and the similarity between alleles linked to highly conserved RNases, suggest a shared ancestral polymorphism also for the F-box genes. The F-box genes identified in European pear were mapped on a segregating population of 91 individuals from the cross 'Abbé Fétel' × 'Max Red Bartlett'. All the genes were placed on the linkage group 17, where the S locus has been placed both in pear and apple maps, and resulted strongly associated to the S-RNase gene. The linkage with the RNase was perfect for some of the F-box genes, while for others very rare single recombination events were identified. The second part of this study was focused on the research of other genes involved in the SI response in pear; it was aimed on one side to the identification of genes differentially expressed in compatible and incompatible crosses, and on the other to the cloning and characterization of the transglutaminase (TGase) gene, whose role may be crucial in pollen rejection. For the identification of differentially expressed genes, controlled pollinations were carried out in four combinations (self pollination, incompatible, half-compatible and fully compatible cross-pollination); expression profiles were compared through cDNA-AFLP. 28 fragments displaying an expression pattern related to compatibility or incompatibility were identified, cloned and sequenced; the sequence analysis allowed to assign a putative annotation to a part of them. The identified genes are involved in very different cellular processes or in defense mechanisms, suggesting a very complex change in gene expression following the pollen/pistil recognition. The pool of genes identified with this technique offers a good basis for further study toward a better understanding of how the SI response is carried out. Among the factors involved in SI response, moreover, an important role may be played by transglutaminase (TGase), an enzyme involved both in post-translational protein modification and in protein cross-linking. The TGase activity detected in pear styles was significantly higher when pollinated in incompatible combinations than in compatible ones, suggesting a role of this enzyme in the abnormal cytoskeletal reorganization observed during pollen rejection reaction. The aim of this part of the work was thus to identify and clone the pear TGase gene; the PCR amplification of fragments of this gene was achieved using primers realized on the alignment between the Arabidopsis TGase gene sequence and several apple EST fragments; the full-length coding sequence of the pear TGase gene was then cloned from cDNA, and provided a precious tool for further study of the in vitro and in vivo action of this enzyme.

Le società pubbliche a partecipazione regionale e locale operanti nei settori dei servizi pubblici locali e dei servizi “strumentali” e quelle con scopo lucrativo: la recente evoluzione legislativa, gli ambiti di attività ed i relativi limiti, le prospettive future.

Con la prima parte, si intende fornire un quadro pressoché esaustivo delle principali disposizioni in materia di società a partecipazione pubblica regionale e locale operanti nel campo dei servizi pubblici locali e della loro interpretazione giurisprudenziale e dottrinale, prendendo le mosse dagli ultimi interventi legislativo. Nella seconda parte, si affronta, invece, il tema dei limiti legislativi alla capacità di azione delle società a partecipazione pubblica e dei connessi dubbi interpretativi, anche alla luce degli orientamenti giurisprudenziali e dottrinali. In particolare, l’analisi riguarda l’art. 13 del decreto”Bersani” e il comma 9 dell’art. 23 bis (ora pedissequamente trasfuso nel comma 33 dell’art. 4 del d.l. n. 138/2011), ossia le principali disposizioni che definiscono, rispettivamente, la capacità di azione delle società (a partecipazione pubblica) strumentali e di quelle operanti nel campo dei servizi pubblici locali titolari di affidamenti diretti (assentiti con modalità diverse dall’evidenza pubblica). Vengono forniti cenni di inquadramento in relazione al cd. procedimento di riordino delle partecipazioni societarie pubbliche previsto dalla legge finanziaria del 2008 (art. 3, commi 27 – 32). Dal combinato disposto delle suddette norme, così come interpretate dalla giurisprudenza costituzionale ed amministrativa, si ricavano, poi, utili indicazioni in ordine alla possibilità, per gli enti pubblici territoriali, di costituire società con scopo meramente lucrativo (ossia, soggetti societari privi del rapporto di strumentalità con gli enti costituenti o partecipanti, chiamati ad operare, in regime di concorrenza, in settori completamente liberalizzati) e società cd. multiutilities (aventi oggetto sociale complesso, la cui attività si estrinseca tanto nel campo dei servizi strumentali, quanto in quello dei servizi pubblici locali), nonché in relazione alla disciplina applicabile all’attività di detti soggetti societari. La finalità ultima del contributo consiste nell'individuazione delle linee guida finalizzate alla classificazione delle società pubbliche in funzione della loro attività.

La costruzione delle relazioni politiche ed economiche tra l'Italia e la Germania occidentale dopo la seconda guerra mondiale (1945-1951)

L’autore ricostruisce ed esamina la storia dei rapporti italo-tedeschi negli anni immediatamente precedenti la riapertura ufficiale delle relazioni diplomatiche tra Italia e Repubblica federale tedesca. Un riavvicinamento economico e politico progressivo, ma che suscitò forti contrasti tra i principali attori della diplomazia italiana. Il saggio si basa su una documentazione conservata presso l’Archivio storico del ministero degli Esteri, l’Archivio centrale dello Stato, l’Archivio storico della Banca d’Italia e l’Archivio Politico del ministero degli Esteri della Repubblica federale. L’autore sostiene che le relazioni economiche italo-tedesche assunsero un ruolo centrale nel processo di elaborazione della politica estera italiana sulla questione tedesca nel corso di questi anni. Prima dell’istituzione della Repubblica federale tedesca, l’Italia divenne un partner economico fondamentale per la Germania occidentale. Tra il 1945 e il 1949 l'Italia fu il primo paese europeo favorevole alla rinascita di un nuovo stato tedesco non sottoposto alla diretta influenza dell’Unione Sovietica. Il presidente del Consiglio De Gasperi e il ministro degli Esteri Sforza per sostenere la nuova Germania attuarono una precisa azione diplomatica di riavvicinamento politico, promuovendo diversi scambi di visite e di incontri con i rappresentanti tedeschi.

I profili fiscali delle operazioni di riorganizzazione societaria transfrontaliere nell'Unione Europea: Il regime fiscale comune della direttiva 2009/133/CE e le prospettive di sviluppo normativo

La tesi affronta le problematiche fiscali della riorganizzazione societaria e la soluzione adoperata nell’Unione europea per le operazioni di carattere transfrontaliere. Si parte dalla definizione del termine “riorganizzazione societaria”, evidenziando le sue matici economiche e la varietà del suo contenuto secondo l’ordinamento giuridico e la branca del diritto di riferimento. Si prosegue sulla correlazione fra l’ampliazione del contenuto della libertà di stabilimento, dovuta maggiormente all’attività interpretativa della Corte di giustizia, e l’allargamento del concetto di riorganizzazione societaria nel quadro normativo dell’Unione. Si procede dunque all’analisi del regime fiscale comune della direttiva 2009/133/CE intravedendosi i suoi sviluppi successivi. In sede di conclusioni, si apporta un breve riassunto sullo stato della questione in Brasile e si riflette sull’attendibilità del modello impositivo dell’Unione quale parametro per una futura riforma fiscale in Brasile.

Transform Tectonics and Non-Volcanic Oceanic Islands

Oceanic islands can be divided, according to their origin, in volcanic and tectonic. Volcanic islands are due to excess volcanism. Tectonic islands are mainly formed due to vertical tectonic motions of blocks of oceanic lithosphere along transverse ridges flanking transform faults at slow and ultraslow mid-ocean ridges. Vertical tectonic motions are due to a reorganization of the geometry of the transform plate boundary, with the transition from a transcurrent tectonics to a transtensive and/or transpressive tectonics, with the formation of the transverse ridges. Tectonic islands can be located also at the ridge–transform intersection: in this case the uplift is due by the movement of the long-lived detachment faults located along the flanks of the mid-ocean ridges. The "Vema" paleoisland (equatorial Atlantic) is at the summit of the southern transverse ridge of the Vema transform. It is now 450 m bsl and it is capped by a carbonate platform 500 m-thick, dated by 87Sr/86Sr at 10 Ma. Three tectonic paleoislands are on the summit of the transverse ridge flanking the Romanche megatrasform (equatorial Atlantic). They are now about 1,000 m bsl and they are formed by 300 m-thick carbonate platforms dated by 87Sr/86Sr, between 11 and 6 Ma. The tectonic paleoisland “Atlantis Bank" is located in the South-Western Indian Ridge, along the Atlantis II transform, and it is today 700 m bsl. The only modern example of oceanic tectonics island is the St. Paul Rocks (equatorial Atlantic), located along the St. Paul transform. This archipelago is the top of a peridotitic massif that it is now a left overstep undergoing transpression. Oceanic volcanic islands are characterized by rapid growth and subsequent thermal subsidence and drowning; in contrast, oceanic tectonic islands may have one or more stages of emersion related to vertical tectonic events along the large oceanic fracture zones.

Città e architettura a Faenza nel Rinascimento. Progetti e strategie di rinnovamento urbano nell'età di Carlo II Manfredi (1468-77)

La tesi ha come oggetto il rinnovamento urbano che fu realizzato a Faenza per opera del suo signore Carlo II Manfredi tra il 1468 e il 1477, d’accordo con il fratello, il vescovo Federico. La prima opera realizzata da Carlo fu il portico a due livelli che dotò di una nuova facciata il suo palazzo di residenza, di origini medievali. Questa architettura sarebbe stata il preludio di un riordino generale della piazza principale della città, probabilmente allo scopo di ricreare un foro all’antica, come prescritto dai trattati di Vitruvio e di Alberti. L’aspetto originale del loggiato rinascimentale, desumibile da documentazione archivistica e iconografica, permette di attribuirlo con una certa probabilità a Giuliano da Maiano. Oltre alla piazza, Carlo riformò profondamente il tessuto urbano, demolendo molti portici lignei di origine medievale, rettificando le principali strade, completando la cerchia muraria. Federico Manfredi nel 1474 diede inizio alla fabbrica della Cattedrale, ricostruita dalle fondamenta su progetto dello stesso Giuliano da Maiano. L’architettura della chiesa ha uno stile largamente debitore all’architettura sacra di Brunelleschi, ma con significative differenze (come la navata definita da un’alternanza tra pilastri e colonne, o la copertura composta da volte a vela). L’abside della cattedrale, estranea al progetto maianesco, fu realizzata nel 1491-92 e mostra alcuni dettagli riconducibili alla coeva architettura di Bramante. A Faenza si realizza in un periodo di tempo brevissimo una profonda trasformazione del volto della città: loggiato, riforma della piazza, riordino delle strade, una nuova cattedrale, tutto contribuisce a dare lustro ai Manfredi e a fare di Faenza una città moderna e in cui si mettono in pratica, forse per la prima volta nell’Italia settentrionale, i dettami di Vitruvio e di Alberti.