Labyrinthum capellae. Le "Annotationes in Marcianum" di Giovanni Scoto Eriugena e la fortuna del neoplatonismo cristiano

The labyrinthum Capella quoted in the title (from a Prudentius of Troyes epistle) represents the allegory of the studium of the liberal arts and the looking for knowledge in the early middle age. This is a capital problem in the early Christianity and, in general, for all the western world, concerning the relationship between faith and science. I studied the evolution of this subject from its birth to Carolingian age, focusing on the most relevant figures, for the western Europe, such Saint Augustine (De doctrina christiana), Martianus Capella (De Nuptiis Philologiae et Mercurii) and Iohannes Scotus Eriugena (Annotationes in Marcianum). Clearly it emerges that there were two opposite ways about this relatioship. According to the first, the human being is capable of get a knowledge about God thanks to its own reason and logical thought processes (by the analysis of the nature as a Speculum Dei); on the other way, only the faith and the grace could give the man the possibility to perceive God, and the Bible is the only book men need to know. From late antiquity to Iohannes Scotus times, a few christian and pagan authors fall into line with first position (the neoplatonic one): Saint Augustine (first part of his life, then he retracted some of his views), Martianus, Calcidius and Macrobius. Other philosophers were not neoplatonic bat believed in the power of the studium: Boethius, Cassiodorus, Isidorus of Seville, Hrabanus Maurus and Lupus of Ferriéres. In order to get an idea of this conception, I finally focused the research on Iohannes Scotus Eriugena's Annotationes in Marcianum. I commented Eriugena's work phrase by phrase trying to catch the sense of his words, the reference, philosophical influences, to trace antecedents and its clouts to later middle age and Chartres school. In this scholastic text Eriugena comments the Capella's work and poses again the question of the studium to his students. Iohannes was a magister in schola Palatina during the time of Carl the Bald, he knew Saint Augustine works, and he knew Boethius, Calcidius, Macrobius, Isidorus and Cassiodorus ones too. He translated Pseudo-Dionysius the Areopagite and Maximus the Confessor. He had a neoplatonic view of Christianity and tried to harmonize the impossibility to know God to man's intellectual capability to get a glimpse of God through the study of the nature. According to this point of view, Eriugena's comment of Martianus Capella was no more a secondary work. It gets more and more importance to understand his research and his mystic, and to understand and really grasp the inner sense of his chief work Periphyseon.

Controllo dell'atto di prensione: coinvolgimento dell'area V6A nell'orientamento del polso

Prehension in an act of coordinated reaching and grasping. The reaching component is concerned with bringing the hand to object to be grasped (transport phase); the grasping component refers to the shaping of the hand according to the object features (grasping phase) (Jeannerod, 1981). Reaching and grasping involve different muscles, proximal and distal muscles respectively, and are controlled by different parietofrontal circuit (Jeannerod et al., 1995): a medial circuit, involving area of superior parietal lobule and dorsal premotor area 6 (PMd) (dorsomedial visual stream), is mainly concerned with reaching; a lateral circuit, involving the inferior parietal lobule and ventral premotor area 6 (PMv) (dorsolateral visual stream), with grasping. Area V6A is located in the caudalmost part of the superior parietal lobule, so it belongs to the dorsomedial visual stream; it contains neurons sensitive to visual stimuli (Galletti et al. 1993, 1996, 1999) as well as cells sensitive to the direction of gaze (Galletti et al. 1995) and cells showing saccade-related activity (Nakamura et al. 1999; Kutz et al. 2003). Area V6A contains also arm-reaching neurons likely involved in the control of the direction of the arm during movements towards objects in the peripersonal space (Galletti et al. 1997; Fattori et al. 2001). The present results confirm this finding and demonstrate that during the reach-to-grasp the V6A neurons are also modulated by the orientation of the wrist. Experiments were approved by the Bioethical Committee of the University of Bologna and were performed in accordance with National laws on care and use of laboratory animals and with the European Communities Council Directive of 24th November 1986 (86/609/EEC), recently revised by the Council of Europe guidelines (Appendix A of Convention ETS 123). Experiments were performed in two awake Macaca fascicularis. Each monkey was trained to sit in a primate chair with the head restrained to perform reaching and grasping arm movements in complete darkness while gazing a small fixation point. The object to be grasped was a handle that could have different orientation. We recorded neural activity from 163 neurons of the anterior parietal sulcus; 116/163 (71%) neurons were modulated by the reach-to-grasp task during the execution of the forward movements toward the target (epoch MOV), 111/163 (68%) during the pulling of the handle (epoch HOLD) and 102/163 during the execution of backward movements (epoch M2) (t_test, p ≤ 0.05). About the 45% of the tested cells turned out to be sensitive to the orientation of the handle (one way ANOVA, p ≤ 0.05). To study how the distal components of the movement, such as the hand preshaping during the reaching of the handle, could influence the neuronal discharge, we compared the neuronal activity during the reaching movements towards the same spatial location in reach-to-point and reach-to-grasp tasks. Both tasks required proximal arm movements; only the reach-to-grasp task required distal movements to orient the wrist and to shape the hand to grasp the handle. The 56% of V6A cells showed significant differences in the neural discharge (one way ANOVA, p ≤ 0.05) between the reach-to-point and the reach-to-grasp tasks during MOV, 54% during HOLD and 52% during M2. These data show that reaching and grasping are processed by the same population of neurons, providing evidence that the coordination of reaching and grasping takes place much earlier than previously thought, i.e., in the parieto-occipital cortex. The data here reported are in agreement with results of lesions to the medial posterior parietal cortex in both monkeys and humans, and with recent imaging data in humans, all of them indicating a functional coupling in the control of reaching and grasping by the medial parietofrontal circuit.

Model reduction techniques in flexible multibody dynamics with application to engine cranktrain simulation

The development of a multibody model of a motorbike engine cranktrain is presented in this work, with an emphasis on flexible component model reduction. A modelling methodology based upon the adoption of non-ideal joints at interface locations, and the inclusion of component flexibility, is developed: both are necessary tasks if one wants to capture dynamic effects which arise in lightweight, high-speed applications. With regard to the first topic, both a ball bearing model and a journal bearing model are implemented, in order to properly capture the dynamic effects of the main connections in the system: angular contact ball bearings are modelled according to a five-DOF nonlinear scheme in order to grasp the crankshaft main bearings behaviour, while an impedance-based hydrodynamic bearing model is implemented providing an enhanced operation prediction at the conrod big end locations. Concerning the second matter, flexible models of the crankshaft and the connecting rod are produced. The well-established Craig-Bampton reduction technique is adopted as a general framework to obtain reduced model representations which are suitable for the subsequent multibody analyses. A particular component mode selection procedure is implemented, based on the concept of Effective Interface Mass, allowing an assessment of the accuracy of the reduced models prior to the nonlinear simulation phase. In addition, a procedure to alleviate the effects of modal truncation, based on the Modal Truncation Augmentation approach, is developed. In order to assess the performances of the proposed modal reduction schemes, numerical tests are performed onto the crankshaft and the conrod models in both frequency and modal domains. A multibody model of the cranktrain is eventually assembled and simulated using a commercial software. Numerical results are presented, demonstrating the effectiveness of the implemented flexible model reduction techniques. The advantages over the conventional frequency-based truncation approach are discussed.

Il consenso informato come strumento di esercizio del diritto alla salute per i pazienti stranieri?

L’elaborato propone una riflessione rispetto all’atto giuridico del consenso informato quale strumento garante dell’esercizio del diritto alla salute per i migranti. Attraverso una riflessione antropologica rispetto alla natura, alla costruzione e alla logica dei diritti universali, verranno analizzate le normative nazionali, europee ed internazionali a tutela del diritto alla salute per i migranti; l’obiettivo della ricerca è indagare l’eventuale scarto tra normative e politiche garantiste nei confronti della salute migrante e l’esistenza di barriere strutturali che impediscono un pieno esercizio del diritto alla salute. L’ipotesi di ricerca si basa sulla reale capacità performativa del consenso informato, proposto solitamente sia come strumento volto ad assicurare la piena professionalità dell’operatore sanitario nell’informare il paziente circa i rischi e i benefici di un determinato trattamento sanitario, sia come garante del principio di autonomia. La ricerca, attraverso un’analisi quanti-qualitativa, ha interrogato il proprio campo, rappresentato da un reparto di ginecologia ed ostetrica, rispetto alle modalità pratiche di porre in essere la firma nei moduli del consenso informato, con particolare attenzione alle specificità proprie delle pazienti migranti. Attraverso l’osservazione partecipante è stato quindi possibile riflettere su aspetti rilevanti, quali le dinamiche quotidiane che vengono a crearsi tra personale sanitario e pazienti, le caratteristiche e i limiti del servizio di mediazione sanitaria, le azioni pratiche della medicina difensiva. In questo senso il tema del “consenso informato”, indagato facendo interagire discipline quali l’antropologia, la bioetica, la filosofia e la sociologia, si è posto sia come lente di lettura privilegiata per comprendere le dinamiche relazionali ad oggi esistenti tra professionisti sanitari e popolazione migrante, ancora vittima di diseguaglianze strutturali, ma altresì come “innesco potenziale” di nuove modalità di intendere la relazione medico-paziente.

Design and Control of Robotic Hands

The application of dexterous robotic hands out of research laboratories has been limited by the intrinsic complexity that these devices present. This is directly reflected as an economically unreasonable cost and a low overall reliability. Within the research reported in this thesis it is shown how the problem of complexity in the design of robotic hands can be tackled, taking advantage of modern technologies (i.e. rapid prototyping), leading to innovative concepts for the design of the mechanical structure, the actuation and sensory systems. The solutions adopted drastically reduce the prototyping and production costs and increase the reliability, reducing the number of parts required and averaging their single reliability factors. In order to get guidelines for the design process, the problem of robotic grasp and manipulation by a dual arm/hand system has been reviewed. In this way, the requirements that should be fulfilled at hardware level to guarantee successful execution of the task has been highlighted. The contribution of this research from the manipulation planning side focuses on the redundancy resolution that arise in the execution of the task in a dexterous arm/hand system. In literature the problem of coordination of arm and hand during manipulation of an object has been widely analyzed in theory but often experimentally demonstrated in simplified robotic setup. Our aim is to cover the lack in the study of this topic and experimentally evaluate it in a complex system as a anthropomorphic arm hand system.