8 resultados para Learning process of arithmetic

em AMS Tesi di Dottorato - Alm@DL - Universit


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INTRODUCTION: The orthotopic left lung transplantation model in rats has been developed to answer a variety of scientific questions in transplant immunology and in the related fields of respiratory diseases. However, its widespread use has been hampered by the complexity of the procedure. AIM OF THE RESEARCH: Our purpose is to provide a detailed description of the procedure of this technique, including the complications and difficulties from the very first microsurgical step until the ultimate successful completion of the transplant procedure. MATERIALS AND METHODS: The transplant procedures were performed by two collaborating transplant surgeons with microsurgical and thoracic surgery skills. A total of 150 left lung transplants in rats were performed. Twenty-seven syngeneic (Lewis to Lewis) and 123 allogeneic (Brown-Norway to Lewis) lung transplants were performed using the cuff technique. RESULTS: In first 50 transplant procedures, post-transplant survival rate was 74% of which 54% reached the end-point of 3 or 7 days post-transplant; whole complication rate was 66%. In the subsequent 50 transplant surgeries (from 51 to 100) post-transplant survival rate increased to 88% of which 56% reached the end-point; whole complication rate was 32 %. In the final 50 transplants (from 101 to 150) post-transplant survival rate was confirmed to be 88% of which 74% reached the end-point; whole complication rate was again 32 %. CONCLUSIONS: One hundred-fifty transplants can represent a reasonable number of procedures to obtain a satisfactory surgical outcome. Training period with simpler animal models is mandatory to develop anesthesiological and microsurgical skills required for successfully develop this model. The collaboration between at least two microsurgeons is mandatory to perform all the simultaneous procedures required for completing the transplant surgery.

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Nowadays the development of new Internal Combustion Engines is mainly driven by the need to reduce tailpipe emissions of pollutants, Green-House Gases and avoid the fossil fuels wasting. The design of dimension and shape of the combustion chamber together with the implementation of different injection strategies e.g., injection timing, spray targeting, higher injection pressure, play a key role in the accomplishment of the aforementioned targets. As far as the match between the fuel injection and evaporation and the combustion chamber shape is concerned, the assessment of the interaction between the liquid fuel spray and the engine walls in gasoline direct injection engines is crucial. The use of numerical simulations is an acknowledged technique to support the study of new technological solutions such as the design of new gasoline blends and of tailored injection strategies to pursue the target mixture formation. The current simulation framework lacks a well-defined best practice for the liquid fuel spray interaction simulation, which is a complex multi-physics problem. This thesis deals with the development of robust methodologies to approach the numerical simulation of the liquid fuel spray interaction with walls and lubricants. The accomplishment of this task was divided into three tasks: i) setup and validation of spray-wall impingement three-dimensional CFD spray simulations; ii) development of a one-dimensional model describing the liquid fuel – lubricant oil interaction; iii) development of a machine learning based algorithm aimed to define which mixture of known pure components mimics the physical behaviour of the real gasoline for the simulation of the liquid fuel spray interaction.

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In recent years we have witnessed important changes: the Second Quantum Revolution is in the spotlight of many countries, and it is creating a new generation of technologies. To unlock the potential of the Second Quantum Revolution, several countries have launched strategic plans and research programs that finance and set the pace of research and development of these new technologies (like the Quantum Flagship, the National Quantum Initiative Act and so on). The increasing pace of technological changes is also challenging science education and institutional systems, requiring them to help to prepare new generations of experts. This work is placed within physics education research and contributes to the challenge by developing an approach and a course about the Second Quantum Revolution. The aims are to promote quantum literacy and, in particular, to value from a cultural and educational perspective the Second Revolution. The dissertation is articulated in two parts. In the first, we unpack the Second Quantum Revolution from a cultural perspective and shed light on the main revolutionary aspects that are elevated to the rank of principles implemented in the design of a course for secondary school students, prospective and in-service teachers. The design process and the educational reconstruction of the activities are presented as well as the results of a pilot study conducted to investigate the impact of the approach on students' understanding and to gather feedback to refine and improve the instructional materials. The second part consists of the exploration of the Second Quantum Revolution as a context to introduce some basic concepts of quantum physics. We present the results of an implementation with secondary school students to investigate if and to what extent external representations could play any role to promote students’ understanding and acceptance of quantum physics as a personal reliable description of the world.

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Subduction zones are the favorite places to generate tsunamigenic earthquakes, where friction between oceanic and continental plates causes the occurrence of a strong seismicity. The topics and the methodologies discussed in this thesis are focussed to the understanding of the rupture process of the seismic sources of great earthquakes that generate tsunamis. The tsunamigenesis is controlled by several kinematical characteristic of the parent earthquake, as the focal mechanism, the depth of the rupture, the slip distribution along the fault area and by the mechanical properties of the source zone. Each of these factors plays a fundamental role in the tsunami generation. Therefore, inferring the source parameters of tsunamigenic earthquakes is crucial to understand the generation of the consequent tsunami and so to mitigate the risk along the coasts. The typical way to proceed when we want to gather information regarding the source process is to have recourse to the inversion of geophysical data that are available. Tsunami data, moreover, are useful to constrain the portion of the fault area that extends offshore, generally close to the trench that, on the contrary, other kinds of data are not able to constrain. In this thesis I have discussed the rupture process of some recent tsunamigenic events, as inferred by means of an inverse method. I have presented the 2003 Tokachi-Oki (Japan) earthquake (Mw 8.1). In this study the slip distribution on the fault has been inferred by inverting tsunami waveform, GPS, and bottom-pressure data. The joint inversion of tsunami and geodetic data has revealed a much better constrain for the slip distribution on the fault rather than the separate inversions of single datasets. Then we have studied the earthquake occurred on 2007 in southern Sumatra (Mw 8.4). By inverting several tsunami waveforms, both in the near and in the far field, we have determined the slip distribution and the mean rupture velocity along the causative fault. Since the largest patch of slip was concentrated on the deepest part of the fault, this is the likely reason for the small tsunami waves that followed the earthquake, pointing out how much the depth of the rupture plays a crucial role in controlling the tsunamigenesis. Finally, we have presented a new rupture model for the great 2004 Sumatra earthquake (Mw 9.2). We have performed the joint inversion of tsunami waveform, GPS and satellite altimetry data, to infer the slip distribution, the slip direction, and the rupture velocity on the fault. Furthermore, in this work we have presented a novel method to estimate, in a self-consistent way, the average rigidity of the source zone. The estimation of the source zone rigidity is important since it may play a significant role in the tsunami generation and, particularly for slow earthquakes, a low rigidity value is sometimes necessary to explain how a relatively low seismic moment earthquake may generate significant tsunamis; this latter point may be relevant for explaining the mechanics of the tsunami earthquakes, one of the open issues in present day seismology. The investigation of these tsunamigenic earthquakes has underlined the importance to use a joint inversion of different geophysical data to determine the rupture characteristics. The results shown here have important implications for the implementation of new tsunami warning systems – particularly in the near-field – the improvement of the current ones, and furthermore for the planning of the inundation maps for tsunami-hazard assessment along the coastal area.

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DI Diesel engine are widely used both for industrial and automotive applications due to their durability and fuel economy. Nonetheless, increasing environmental concerns force that type of engine to comply with increasingly demanding emission limits, so that, it has become mandatory to develop a robust design methodology of the DI Diesel combustion system focused on reduction of soot and NOx simultaneously while maintaining a reasonable fuel economy. In recent years, genetic algorithms and CFD three-dimensional combustion simulations have been successfully applied to that kind of problem. However, combining GAs optimization with actual CFD three-dimensional combustion simulations can be too onerous since a large number of calculations is usually needed for the genetic algorithm to converge, resulting in a high computational cost and, thus, limiting the suitability of this method for industrial processes. In order to make the optimization process less time-consuming, CFD simulations can be more conveniently used to generate a training set for the learning process of an artificial neural network which, once correctly trained, can be used to forecast the engine outputs as a function of the design parameters during a GA optimization performing a so-called virtual optimization. In the current work, a numerical methodology for the multi-objective virtual optimization of the combustion of an automotive DI Diesel engine, which relies on artificial neural networks and genetic algorithms, was developed.

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In Bosnia Herzegovina the development of clear policy objectives and endorsement of a long-term, coherent and mutual agricultural and rural development policy have also been affected by structural problems: a lack of reliable information on population and other relevant issues, the absence of an adequate land registry system and cadastre. Moreover in BiH the agricultural and rural sectors are characterized by many factors that have typically affected transition countries such as land fragmentation, lack of agricultural mechanization and outdated production technologies, and rural aging, high unemployment and out-migration. In such a framework the condition and role of women in rural areas suffered for the lack of gender disaggregated data and a consequent poor information that lead to the exclusion of gender related questions in the agenda of public institutions and to the absence of targeted policy interventions. The aim of the research is to investigate the role and condition of women in the rural development process of Republic of Srpska and to analyze the capacity of extension services to stimulate their empowerment. Specific research questions include the status of women in the rural areas of Republic of Srpska, the role of government in fostering the empowerment of rural women, and the role of the extension service in supporting rural women. The methodology - inspired by the case study method developed by R. Yin - is designed along the three specific research questions that are used as building blocks. Each of the three research questions is investigated with a combination of methodological tools - including surveys, experts interviews and focus groups - aimed to overcome the lack of data and knowledge that characterize the research objectives.

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Alongside the developments in behavioural economics, the concept of nudge was introduced as an intervention able to guide individual behaviour towards better choices without using coercion or incentives. While behavioural teams were created inside governmental units and regulatory authorities, nudging emerged in regulatory discourse, being increasingly regarded as a regulatory instrument that could overcome the disadvantages of other tools. This thesis analyses the viability of incorporating nudges into regulation. In particular, it investigates the implications for regulators of bringing iterative experimental testing – a widespread nudge design methodology outside regulation – into their own design practices. Nudges outside regulation are routinely designed using experiments of all kinds. This thesis intends to answer whether design premises rooted in iterative experimentation are still valid in the regulatory space, an arena that nudging entered into and that is distinct from the one where it originally emerged. The design and provision of nudges using the premises of iterative experimental testing is possible, but at a cost and burden for regulatory nudge designers. Therefore, the thesis evaluates how this burden can be reduced, in particular how nudges can be feasibly designed and provided through regulation or, put differently, how to more efficiently design and provide nudging as a regulatory tool.

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Angela da Foligno’s Liber is a fundamental text for the scholar of Women Mystics between the XIIIth and the XIVth century in Italy and all over Europe, and it has been chosen in my research because of its originality, with refer of its feminine and franciscan essence. Angela teaches to the italian hagiographic tradition the internal point of view of the holy woman, who becomes the teller of her both ordinary and extraordinary experiences. After giving references about the religious and social historical universe in evolution during the XIIth century, my research proceeds with a linguistic and rhetorical analysis based upon the Liber. I have been searching in Angela’s text and in contemporary italian feminine hagiography the sensory metaphor of “tasting”. That kind of metaphor has an ancient memory and, thanks to the Origene’s studies - the Christian Father of the IIIrd century - we can easily recognize it already in the Bible; Origene identifies the sensory metaphor as a rhetoric system, able to exemplify the God learning process of soul. Theory of “spiritual senses”, theory of vision and rhetoric, evolving from the IIIrd to the XIIIth century, are the theological and linguistic heritage of our feminine and franciscan literature. Inside of that, the metaphor of “tasting” moves and changes, therefore becoming the favourite way of mystics to represent the contact of their souls with God.