Senso di comunita' ed esperienza migratoria: il caso degli studenti stranieri dell'Universita' di Pisa

Nel contesto delle migrazioni internazionali, stanno acquisendo sempre maggiore importanza e valore le migrazioni di tipo transnazionale. L’esperienza migratoria si sviluppa in direzione transnazionale quando il migrante non rompe definitivamente i legami con la propria comunità di origine, ma al contrario consolida legami politici, economici, culturali e sociali attraverso i confini di due o più Stati. Questi legami contribuiscono alla creazione di spazi sociali transnazionali di interazione. In alcuni casi, questi spazi sociali si configurano come delle vere e proprie comunità transnazionali, caratterizzate, per quanto riguarda la dimensione espressiva, da un forte senso di appartenenza alla comunità e, per quanto riguarda la dimensione strumentale, da un intenso coinvolgimento in attività transnazionali di tipo economico, politico e socio-culturale. Nel presente lavoro, ho voluto approfondire lo studio di queste comunità transnazionali attraverso una ricerca sugli studenti stranieri dell’Università di Pisa. Lo scopo dell’indagine è duplice. Da una parte, la ricerca mira alla precisazione terminologica del concetto di comunità transnazionale. Dall’altra, si vuole contribuire allo sviluppo dell’approccio di ricerca quantitativo allo studio del transnazionalismo, impiegando strumenti di rilevazione che permettano un certo grado di generalizzazione e confronto dei risultati ottenuti. Per rispondere ad entrambe queste esigenze si è impiegato il senso di comunità. Da un punto di vista concettuale, il senso di comunità esprime l’orientamento espressivo e individuale del migrante, che lo fa sentire parte di una comunità. Se il migrante prova questo senso di appartenenza verso la propria comunità di origine, si può parlare dell’esistenza di una comunità transnazionale, poiché si basa su legami tra individui che risiedono in due o più stati diversi. Inoltre, la trasformazione di questo concetto teorico in un indice del senso di comunità permette di rispondere alle esigenze metodologiche di confronto e generalizzazione dei risultati ottenuti

Critical phenomena in spherical gravitational collapse

In general relativity, critical collapse is a phenomenon for which in dependence of the choice of some parameter of initial data, the resulting spacetimes can be regular or singular and so the evolution could finish in dispersal or in a formation of a black hole/naked singularity, respectively. Moreover, in the second case, it was found the power-law scale for the black hole masses. These phenomena in gravitational collapse were first found by Choptuik in numerical simulation of spherically symmetric massless scalar field. In the present thesis the study of these example have been extended to a wider class of models. The collapsing time and the bouncing time, in order to understand if the collapse or the bouncing happens in a finite time, have been analysed and we have proved that it is so. Moreover we have observed that also at the end of supercritical evolution the singularity is naked and so the singularity is not covered

Validazione del software Helyx, basato su tecnologia OpenFOAM, applicato all'aerodinamica di una vettura.

Il presente lavoro di tesi, svolto in collaborazione con Engys S.p.A, ha lo scopo di sondare le potenzialità di Helyx, un nuovo software CFD basato su tecnologia OpenFoam, applicato all’aerodinamica di una vettura sportiva: la F458 Italia. Ci si prefigge di trovare i settaggi ottimali per e seguire una simulazione CFD su una vettura, avvalendosi anche del confronto con una simulazione effettuata con il software Fluent sulla stessa vettura. In sostanza, la caratteristica fondamentale di Helyx è il fatto di essere provvisto di una GUI (Grafic User Interface), che permette di velocizzare il processo di impostazione della simulazione rispetto ad OpenFOAM. In più, rispetto a quest’ultimo, Engys ha provveduto ad implementare alcune applicazioni. Un vantaggio di utilizzare software basati su librerie libere è quello di adattare il solutore alle proprie esigenze

Factors influencing interactions in zoos: animal-keeper relationship, animal-public interactions and solitary animals groups

Interactions that animals experience can have a significant influence on their health and welfare. These interactions can occur between animals themselves, but also between animals and keepers, and animals and the public. Human and non-human animals come into contact with each other in a variety of settings, and wherever there is contact there is the opportunity for interaction to take place. Interaction with companion animals are well known, but human–animal interaction (HAR) (Hosey, 2008) also occurs in the context of farms (Hemsworth and Gonyou, 1997; Hemsworth, 2003), laboratories (Chang and Hart, 2002), zoos (Kreger and Mench, 1995) and even the wild (e.g. Cassini, 2001). This project proposes a permanent monitoring scheme to record animal-human interactions and animal-animal interactions in zoos. This will be accompanied by a survey of animal personality for welfare, husbandry, breeding programs and reintroduction purposes. The pilot project is currently based on direct monitoring of animal behaviour, use of time lapse cameras and animal personality questionnaires completed by experienced keepers. The goal of this project is to create a network between zoos to explore the aforementioned interactions to produce husbandry protocols and explore personality and behavioural traits in multiple species. We present provisional data regarding polar bear (Fasano Zoosafari, Italy), Sumatran tigers, Amur tigers and Asiatic lion (ZSL London and Whipsnade zoo) interactions with humans and conspecifics. This data is collected across a broad range of environmental conditions and outlines the monitoring protocols developed to collect this data. The first year data show the great adaptability of these species to ex situ environments, low or absent negative impact of visitors’ presence and the relevance of individual personality in these interactions

Partitioning qubits in hypergraph product codes to implement logical gates

The promise of high-rate low-density parity check (LDPC) codes to substantially reduce the overhead of fault-tolerant quantum computation depends on constructing efficient, fault-tolerant implementations of logical gates on such codes. Transversal gates are the simplest type of fault-tolerant gate, but the potential of transversal gates on LDPC codes has hitherto been largely neglected. We investigate the transversal gates that can be implemented in hypergraph product codes, a class of LDPC codes. Our analysis is aided by the construction of a symplectic canonical basis for the logical operators of hypergraph product codes, a result that may be of independent interest. We show that in these codes transversal gates can implement Hadamard (up to logical SWAP gates) and control-Z on all logical qubits. Moreover, we show that sequences of transversal operations, interleaved with error correction, allow implementation of entangling gates between arbitrary pairs of logical qubits in the same code block. We thereby demonstrate that transversal gates can be used as the basis for universal quantum computing on LDPC codes, when supplemented with state injection

Nanosegregation in Na2C60

There is continuous interest in the nature of alkali metal fullerides containing C(4)(60) and C(2)(60), because these compounds are believed to be nonmagnetic Mott–Jahn–Teller insulators. This idea could be verified in the case of A(4)C(60), but Na(2)C(60) is more controversial. By comparing the results of infrared spectroscopy and X-ray diffraction, we found that Na(2)C(60) is segregated into 3-10 nm large regions. The two main phases of the material are insulating C(60) and metallic Na(3)C(60). We found by neutron scattering that the diffusion of sodium ions becomes faster on heating. Above 470 K Na(2)C(60) is homogeneous and we show IR spectroscopic evidence of a Jahn–Teller distorted C(2)(60) anion

A ‘healthy baby’: The double imperative of preimplantation genetic diagnosis

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2010 The Authors.This article reports from a study exploring the social processes, meanings and institutions that frame and produce ‘ethical problems’ and clinical dilemmas for practitioners, scientists and others working in the specialty of preimplantation genetic diagnosis (PGD). A major topic in the data was that, in contrast to IVF, the aim of PGD is to transfer to the woman’s womb only those embryos likely to be unaffected by serious genetic disorders; that is, to produce ‘healthy babies’. Staff described the complex processes through which embryos in each treatment cycle must meet a double imperative: they must be judged viable by embryologists and ‘unaffected’ by geneticists. In this article, we focus on some of the ethical, social and occupational issues for staff ensuing from PGD’s double imperative.The Wellcome Trus

Transversal Diagonal Logical Operators for Stabiliser Codes

Storing quantum information in a quantum error correction code can protect it from errors, but the ability to transform the stored quantum information in a fault tolerant way is equally important. Logical Pauli group operators can be implemented on Calderbank-Shor-Steane (CSS) codes, a commonly-studied category of codes, by applying a series of physical Pauli X and Z gates. Logical operators of this form are fault-tolerant because each qubit is acted upon by at most one gate, limiting the spread of errors, and are referred to as transversal logical operators. Identifying transversal logical operators outside the Pauli group is less well understood. Pauli operators are the first level of the Clifford hierarchy which is deeply connected to fault-tolerance and universality. In this work, we study transversal logical operators composed of single- and multi-qubit diagonal Clifford hierarchy gates. We demonstrate algorithms for identifying all transversal diagonal logical operators on a CSS code that are more general or have lower computational complexity than previous methods. We also show a method for constructing CSS codes that have a desired diagonal logical Clifford hierarchy operator implemented using single qubit phase gates. Our methods rely on representing operators composed of diagonal Clifford hierarchy gates as diagonal XP operators and this technique may have broader applications.Comment: 24 pages + 11 page appendix, 4 figures, comments welcom