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Neural Correlates of Semantic Memory: from Neuropsychology to Neuroimaging
No full textThis thesis will describe two functional Magnetic Resonance Imaging (fMRI) experiments and one Voxel-Based Morphometry (VBM) study, each investigating how the human brain identifies objects and their associated properties. In particular, we used three different categories of objects – living (animals), nonliving (tools and nontools) and faces (famous and non-famous) – to examine the type of knowledge attribute in question: one perceptual (movement) and two semantic attributes (typical object location and biographic knowledge).
We know from neuropsychological literature that the most anterior portions of the temporal cortices critically support human conceptual knowledge. Unfortunately, the Anterior Temporal Lobe (ATL) is a challenging region for fMRI due to susceptibility artifacts, especially at high fields. For these reasons we established an optimized fMRI protocol (described in the second Chapter) by adjusting key acquisition parameters like phase-encoding gradient polarity, slice thickness, echo time, and slice angle. The protocol gave reliable Blood-Oxygen-Level Dependence (BOLD) signal sensitivity in the ATL.
Clinical data describe patients with specific semantic impairments at the level of category (living, nonliving) as well as disproportionate deficits for a modality or type of knowledge (e.g., visual/perceptual knowledge or manipulation knowledge). Functional neuroimaging studies on semantic organization with normal subjects found an “action network” specific for tools rather than living items. In the first experiment (Chapter 3) we devised an fMRI paradigm to investigate the processing of movement (action) and place (encyclopedic) features, and their influence on category-specific activations. Within the “movement network” statistical analyses did not show any significant interaction between categories. These findings suggest that the visuomotor “action network” is not specific for tools because it is also activated when the action related knowledge is elicited for other categories, such as animals.
The second and the third experiment (Chapter 4) focus on the processing of faces. Neuropsychological literature attributes semantic and lexical retrieval deficits in patients to ATL lesions. In Part I of Chapter 4, we report data from a VBM study on patients with known lesions in the temporal lobe. Unfortunately, as far as we know, data on patients and functional neuroimaging in healthy individuals has not clarified the differential role of this area in the two mental operations because semantic and lexical processes usually occur simultaneously and automatically. In Part II, we devised an event-related fMRI activation paradigm that allowed us to study the identification (i.e., association of semantic biographical information) of celebrities, with and without the ability to retrieve the proper name. While semantic retrieval reliably activated the ATL, only more posterior areas in the left temporal and temporal-parietal junction were significantly modulated by covert lexical retrieval. These results support findings from patients with ATL lesions and suggest that their anomia is due to semantic rather than lexical retrieval impairment
Managing Ubiquitous Scientific Knowledge Objects
No full textScientific discourse, as the basic unit of dissemination and exploitation of research results, has steadily enhanced their accessibility and reusability in response to the advancement of web technologies. A highly semantic enriched publication always makes its information and data much easier to search, navigate, disseminate and reuse, whereas most online articles today are still electronic facsimiles of linear structured papers, with shallow metadata descriptions, lacking in semantic knowledge and interlinked relationships between elementary modules of content.
In this dissertation, we propose a Scientific Knowledge Objects (SKO) framework in terms of a theory of structural knowledge- SKO Types, a methodology for scientific discourse representation- SKO Patterns, a tool for semantic authoring and annotation- SKO TeX, and an application of SKO management- the Conference of the Future, in the context of the emerging Social Web and Semantic Web
Impact of Seismic Vulnerability on Bridge Management Systems
No full textMotivated by the potential vulnerability of their road infrastructure, many national authorities and local Departments of Transportation are incorporating seismic risk assessment in their management systems. This Dissertation aims to develop methods and tools for seismic risk analysis that can be used in a Bridge Management System (BMS); helping bridge owners to assess the costs of repair, retrofit and replacement of the bridges under their responsibility.
More specifically, these tools are designed to offer estimates of:
(1) the seismic risk to single components of bridges and their expected performance after an earthquake.
(2) the impact a priori (i.e. before an earthquake) of a given earthquake on the operation of a road network, in terms of connectivity between different locations.
(3) the damage a posteriori (i.e. after an earthquake) to road network operation, based on prior knowledge of network vulnerability and on the observed damage to a small number of single bridges.
The effectiveness of these methods is tested and validated in a specific case study, the bridge stock of the Autonomous Province of Trento (APT) in Italy.
To address the first point, I will first introduce the fragility curve method for risk assessment of individual bridges. The Hazus model is chosen as the most appropriate and is applied to the bridges of the APT stock. Once the fragility curves for all the bridges have been generated, a risk analysis is performed for three earthquake scenarios (with return periods of 72, 475 and 2475 years) and four condition states (operational, damage, life safety and collapse limit state). Next, I will extend the results of the component level analysis to the network level: the APT road network is modeled in the form of a graph and the problem of connectivity between two locations is analyzed. A shortest path algorithm is introduced and implemented to identify the best path between any two given places. Correlation in capacity and demand among bridges is not considered at this stage.
After reiterating the fundamentals of probability theory, the theory of Bayesian Networks is introduced. The Bayesian Network approach is used to incorporate mutual correlation in capacity and demand, in risk assessment of a bridge stock. The concept is first formulated and illustrated on a simple case (the ‘twin bridge problem’), then extended to the general case of a full stock. I will show how the same framework can be used in post-earthquake assessment problems, where the evidence of the state of one or more bridges affects the prediction of the performance of another bridge. The outcomes and the limits of this work are discussed at the end of the Thesis
La condizione liminale della consulenza: racconti di lavoro tra autonomia e organizzazione
No full textLa tesi in oggetto analizza l'identità professionale della consulenza di management in Italia al fine di identificare le modalità attraverso le quali questi lavoratori esplicitano il proprio professionalismo nel discorso. A ciò si aggiunge l’interesse di studiare quali conseguenze ha in termini di welfare, diritti e riconoscimento sociale della loro attività il fatto che, sebbene siano professionisti di fatto, non siano compresi dal sistema formale delle professioni, ancora incentrato sul modello delle professioni liberali.
Questo tema viene declinato analizzando tre dimensioni (professionalismo, imprenditorialità e autonomia) che ritengo trasversali al mondo del lavoro contemporaneo e strategiche per comprendere le trasformazioni in atto: il tema del professionalismo, in particolare, diventa la chiave di lettura sotterranea che guida tutta la struttura del lavoro e che mi consente di legare il tema delle trasformazioni del lavoro con quello delle professioni, a cui di fatto queste attività appartengono
Thomas Stanley, editore di Eschilo
No full textA survey on Thomas Stanley's Aeschylus edition, his sources and his philological work
Exploiting SAT and SMT Techniques for Automated Reasoning and Ontology Manipulation in Description Logics
No full textDescription Logics (DLs) are a family of logic-based knowledge representation formalisms aimed at representing the knowledge of an application domain in a structured way one of whose main characteristic is the emphasis on reasoning.
Since the last two decades Description logics have been widely studied and applied to numerous areas of computer science (including artificial intelligence, formal verification, database theory, natural language processing and distributed computing). In recent years, however, the interest in the problem of automated reasoning in Description Logics has seen a tremendous growth because of the explosion of new notable applications in the domains of Semantic Web and of bio-medical ontologies. The more real-world problems are represented through DL-based ontologies the more these new applications represents a challenge due to the required efficiency in handling complex logical constructors (e.g. numerical constraints) and in handling the huge dimensions of this kind of ontologies. For these reasons the development of efficient algorithms and procedures for reasoning in Description Logic has become crucial.
SAT-based technologies, in the meanwhile, proved to be mature and largely successful in many other automated reasoning fields, first of all on many very hard practical applications of formal verification, often huge characterized by problems of huge dimension. In the last twenty years, in fact, we have witnessed an impressive advance in the efficiency of SAT techniques, which has brought problems of hundreds of millions of clauses and variables to be at the reach of the freely-available state-of-the-art solvers. As a consequence, many problems have been successfully solved by mean of SAT-based techniques and these approaches are currently state-of-the-art in the respective communities (among all Model Checking). Furthermore, the progress in SAT-solving techniques, together with the concrete needs from real applications, have inspired significant research on richer and more expressive Boolean formalism, like Satisfiability Modulo Theories (SMT), and on the use of the SAT formalism to solve problems with a wider extent (e.g. to compute interpolants, unsatisfiable cores, all-SAT).
The research trends in Description Logic, its manifold practical applications, the quest of efficient and scalable procedures, on one hand, the wide variety of mature and efficient techniques offered by the SAT research area, on the other hand, motivated our research. In this thesis dissertation we explore the idea of exploiting the power and efficiency of state-of-the-art SAT-based techniques for automated reasoning and ontology manipulation in Description Logics, proposing a convenient alternative to the traditional tableau based algorithms.
With this aim we propose and develop novel and complete approaches able to solve Description Logic problems as SAT and SMT ones, by mean of sound and complete encodings. On these encodings we develop new procedures and optimizations techniques based on a variety of existing SAT-based formalisms and technologies. In this work, in particular, we focus on three gradually harder reasoning problems in Description Logics which tackle increasingly more expressive languages or increasingly harder reasoning services, among which we face also non-standard services supporting the debugging of ontologies like modularization and axiom pinpointing. We implemented our approaches in tools which integrate with the available SAT/SMT-solvers; finally, we show the effectiveness of our novel approaches through very extensive empirical evaluations on benchmarks and ontologies from real application, in which we compare our performance against the other state-of-the-art available systems.
Notice that any advance in the exploited Boolean reasoning techniques/tools will be freely inherited from our proposed approaches extending also to Description Logics/ontologies the benefits of the observable great and fast advance in the efficiency of SAT-based techniques
Progress of Monte Carlo methods in nuclear physics using EFT-based NN interaction and in hypernuclear systems.
No full textIntroduction In this thesis I report the work of my PhD; it treated two different topics, both related by a third one, that is the computational method that I use to solve them. I worked on EFT-theories for nuclear systems and on Hypernuclei.
I tried to compute the ground state properties of both systems using Monte Carlo methods.
In the first part of my thesis I briefly describe the Monte Carlo methods that I used: VMC (Variational Monte Carlo), DMC (Diffusion Monte Carlo), AFDMC (Auxiliary Field Diffusion Monte Carlo) and AFQMC (Auxiliary Field Quantum Monte Carlo) algorithms. I also report some new improvements relative to these methods that I tried or suggested: I remember the fixed hypernode extension (§ 2.6.2) for the DMC algorithm, the inclusion of the L2 term (§ 3.10) and of the exchange term (§ 3.11) into the AFDMC propagator. These last two are based on the same idea used by K. Schmidt to include the spin-orbit term in the AFDMC propagator (§ 3.9). We mainly use the AFDMC algorithm but at the end of the first part I describe also the AFQMC method. This is quite similar in principle to AFDMC, but it was newer used for nuclear systems. Moreover, there are some details that let us hope to be able to overcome with AFQMC some limitations that we find in AFDMC algorithm. However we do not report any result relative to AFQMC algorithm, because we start to implement it in the last months and our code still requires many tests and debug.
In the second part I report our attempt of describing the nucleon-nucleon interaction using EFT-theory within AFDMC method. I explain all our tests to solve the ground state of a nucleus within this method; hence I show also the problems that we found and the attempts that we tried to overcome them before to leave this project.
In the third part I report our work about Hypernuclei; we tried to fit part of the ÎN interaction and to compute the Hypernuclei Î-hyperon separation energy. Nevertheless we found some good and encouraging results, we noticed that the fixed-phase approximation used in AFDMC algorithm was not so small like assumed. Because of that, in order to obtain interesting results, we need to improve this approximations or to use a better method; hence we looked at AFQMC algorithm aiming to quickly reach good results
Uomo e Animale: identità in divenire: Incontri metamorfici in Fuglane di Tarjei Vesaas e in Gepardene di Finn Carling
No full text“Metamorphosis and identity are the two limits of human existence, incompatible with one another, but complementary in that human life exists in a movement between these two limits.”
La metamorfosi è un fenomeno diffuso tanto in natura quanto nella mitologia e in letteratura: con questo termine si può infatti designare la trasformazione di piante, animali e uomini intendendone lo sviluppo attraverso cambiamenti di forma, ma anche l’attraversamento di regni di diversa natura, passando così dall’appannaggio della scienza a quello dell’immaginazione. “Avant d’être un thème littéraire, la métamorphose a été un mythe; et avant d’être un mythe, un phénomène observable dans les quatre règnes de la nature: minéral, végétal, animal et humain”.
Nel presente studio il fenomeno metamorfico sarà affrontato alla luce della relazione tra uomo ed animale: la vicinanza tra i due “regni” e l’instabilità del confine ontologico tra di essi è tale da aver dato vita ad una ricchissima letteratura intorno al loro contatto e al loro possibile intreccio, che va dalle Metamorfosi ovidiane agli splendidi ibridi postmoderni di Angela Carter. La metamorfosi è il tema letterario che più di ogni altro riesce a tradurre il paradosso dell’identità nel cambiamento: esso possiede un grande potenziale sovversivo di natura politica, sociale, esistenziale. Pierre Brunel, nella sua ricerca diacronica sul mito della metamorfosi da Ovidio a Kafka , cerca infatti di spiegarne le origini e le funzioni e conclude affermando che esso traduce la domanda universale dell’uomo sul suo posto nel mondo, sul suo passato prenatale e sul suo futuro dopo la morte.
È prevalentemente da un punto di vista filosofico e nelle sue implicazioni esistenziali che si cercherà di indagare il processo metamorfico tra uomo e animale nel modo in cui si manifesta nell’opera di due scrittori norvegesi del Novecento, Tarjei Vesaas e Finn Carling, e in particolare nei due rispettivi romanzi Fuglane (Gli uccelli, 1957) e Gepardene (I ghepardi, 1998).
La presente riflessione prende avvio dall’indagine intorno alla portata e alla natura della presenza animale all’interno del linguaggio umano e del testo letterario, per poi aprire il discorso sulla precarietà del confine ontologico che separa uomini ed animali. Si procede dunque ad una lettura del rapporto tra i primi ed i secondi in termini di relazione oggettuale, per soffermarsi soprattutto sulle modalità in cui essa entra in crisi nel momento in cui l’uomo e l’animale incorrono in un rapporto di tipo metamorfico. La prima parte di questo lavoro si conclude, infine, con la presentazione delle proposte teoriche che Gilles Deleuze e Félix Guattari hanno costruito proprio intorno alla crisi della relazione oggettuale, ovvero teorizzando il vero e proprio sgretolamento di ogni sistema di pensiero binario, che ruotano intorno alla natura mobile, in divenire, dell’uomo e sono esposte in Mille plateaux. Un posto centrale è riservato nei Mille plateaux proprio al divenir-animale dell’uomo.
Nella seconda parte di questo studio, dedicata alla presentazione di Tarjei Vesaas e Finn Carling, si è scelto di fornire le informazioni necessarie allestendo un percorso che mettesse in luce, nella loro scrittura, l’attenzione “ecologica” verso il mondo animale ma anche, e soprattutto, il loro sguardo attento sul presente, sulla trasformazione antropologica e la fragilità esistenziale dell’uomo di fine Novecento. Si passa dunque ad una presentazione della loro opera che si propone di illustrare alcune modalità di comparsa delle figure animali: il loro utilizzo, le loro funzioni, il loro rapporto con i personaggi umani.
L’ultima parte del lavoro analizza infine i due romanzi Fuglane e Gepardene alla luce delle relazioni, degli inseguimenti e degli incontri tra i protagonisti umani e gli animali, incontri che si spingono fino a controversi momenti metamorfici. È possibile scrivere un racconto di metamorfosi nell’ambito di una scrittura “realista”? È possibile raccontare una metamorfosi “reale” e non prettamente metaforica? È possibile infine annoverare il fenomeno metamorfico tra le cose narrabili o si rischia di incorrere nei limiti del linguaggio? Queste alcune delle domande che il mio lavoro, lungi dal risolvere, solleva
Category and Space in the Ventral Stream
Get PDFThe experiments described in this thesis address the question of how category and space are represented in the brain. First, we asked whether object category is encoded in specialized modules or whether it is distributed throughout the ventral stream. To this means we conducted an fMRI adaptation experiment and tested whether face- and house-selective ventral stream areas exhibit adaptation across object categories. We found that both areas adapted to both preferred and non-preferred object stimuli, and the magnitude of the adaptation effect was higher for preferred categories. Our study favors a theory of a distributed processing of object information and undermines the notion of modules that exclusively encode one category. Second, we investigated the extent of space representation in ventral stream areas. We combined retinotopic mapping techniques with the presentation of object stimuli. We were able to demonstrate that the ventral stream areas FFA and PPA are highly space-sensitive and that the representation of space covers nearly the entire visual field. We found indications that spatial sensitivity is highest for the preferred category, indicating that the representations of category and of space interact. Furthermore, voxels that were more robustly sensitive to space were at the same time less sensitive to category membership, indicating a trade-off of sensitivity for category and space. Our studies shed new light on the functional properties of the ventral stream, as we have demonstrated that ventral stream areas are less specialized in object identity than previously thought, and instead perform additional computations on spatial aspects of visual stimuli
Small Fruit Production in Mountain Areas with the use of Biocontrol Agents: Investigating Farmers' Attitudes and Consumers' Choice in Trentino.
No full textIn recent years, concerns have been raised over the effects of the overuse of agricultural pesticides on the environment and human health. Biocontrol agents (BCAs) can serve as an alternative to chemicals in integrated pest management (IPM) systems. Although the adoption of BCAs is strongly affected by the socioeconomic environment in which they are to be applied and by farmers’ attitudes, these factors have been poorly investigated in BCA research and development programs. This thesis empirically investigates the farmers’ attitude to an IPM that employs BCAs extensively to understand which are the factors that may prevent the adoption on large scale for this strategy and which may represent the key for its success. Moreover, it aims to provide some insight about the role of different source of information and of government in spreading information about BCAs.
Simultaneously with the evaluation of the agro-systems (farms) in which there is the highest probability for successful BCA implementation, it is also important to understand whether there would be a market for products obtained with BCAs. This thesis focuses on identifying the attributes that have been shown to be relevant and determinant in purchasing and willingness to pay (WTP) for sustainable grown fruits and vegetables and on evaluating the consumers’ preferences and their willingness to pay for fruit obtained with BCAs. Moreover, it aims to discover whether the consumers choice is influenced by threshold values (cut-offs)