Sistemi di controllo per impianti di rigassificazione di gas naturale

Il presente lavoro di tesi propone di analizzare i diversi metodi utilizzati per la rigassificazione del gas naturale liquefatto. È stato preso a riferimento un impianto di rigassificazione di GNL off shore per realizzare un modello simulato di processo con il software AspenHYSYS®. Si è analizzato il comportamento dinamico dell’impianto nella modalità di svuotamento dei serbatoi di stoccaggio e rigassificazione di GNL, in presenza di disturbi

Preparazione e caratterizzazione di nanocompositi a matrice termoplastica con elevata concentrazione di argilla

Il presente lavoro consiste nella preparazione di miscele polimero-argilla ad elevate concentrazioni di argilla (masterbatches).Le miscele sono state preparate a base di EVA14 ed EVA28 con il 40% in peso di cloisite 20A e cloisite 30B. I masterbatches, preparati in brabender sono stati sottoposti ad analisi ai raggi X e diluiti con polimero vergine. Le diluizioni ottenute sono state sottoposte a caratterizzazione e confrontate con le miscele preparate direttamente. Sono stati poi effettuati studi diversi sulle due argille utilizzate. I compositi sono stati preparati con tecniche diverse dall'intercalazione diretta nel fuso; intercalazione in soluzione e miscela delle polveri. Tutti i campioni ottenuti sono stati sottoposti ad analisi ai raggi X e confrontati i risultati

ESSAYS ON ECONOMIC GROWTH AND HEALTH

This thesis analyzes some aspects of the relationship between health and economic growth from a theoretical point of view. It consists of two papers, one co-authored and one single-authored. The co-authored paper \u201cChildren's health, human capital accumulation, and R&D-based economic growth\u201d describes the role of children's health for human capital accumulation and for long-run economic growth. For this purpose we design an R&D-based growth model in which the stock of human capital of the next generation is determined by parental education and health investments. We show that i) there is a complementarity between education and health: if parents want to have better educated children, they also raise health investments and vice versa; ii) parental health investments exert an unambiguously positive effect on long-run economic growth, iii) faster population growth reduces long-run economic growth. These results are consistent with the empirical evidence for modern economies in the twentieth century. In the single-authored paper \u201cDifferent Types of Health Expenditures in an OLG framework: living longer or working better?\u201d, the health status of individuals affects their longevity and their labor productivity. We include public health expenditures into an overlapping-generations model. The government faces the trade-off investing its revenues either into the health expenditure that makes the labor force productive, or into the health expenditure that increases life expectancy. We show how the government optimally allocates the resources between the two types of health expenditures. The results are remarkable because by using a straightforward structure of the economy, we are able to combine two strings of the existing literature about the impacts of health: higher life expectancy and higher worker productivity

DGK\u3b1 in Neutrophil Biology and Its Implications for Respiratory Diseases

Diacylglycerol kinases (DGKs) play a key role in phosphoinositide signaling by removing diacylglycerol and generating phosphatidic acid. Besides the well-documented role of DGK\u3b1 and DGK\u3b6 as negative regulators of lymphocyte responses, a robust body of literature points to those enzymes, and specifically DGK\u3b1, as crucial regulators of leukocyte function. Upon neutrophil stimulation, DGK\u3b1 activation is necessary for migration and a productive response. The role of DGK\u3b1 in neutrophils is evidenced by its aberrant behavior in juvenile periodontitis patients, which express an inactive DGK\u3b1 transcript. Together with in vitro experiments, this suggests that DGKs may represent potential therapeutic targets for disorders where inflammation, and neutrophils in particular, plays a major role. In this paper we focus on obstructive respiratory diseases, including asthma and chronic obstructive pulmonary disease (COPD), but also rare genetic diseases such as alpha-1-antitrypsin deficiency. Indeed, the biological role of DGK\u3b1 is understudied outside the T lymphocyte field. The recent wave of research aiming to develop novel and specific inhibitors as well as KO mice will allow a better understanding of DGK\u2019s role in neutrophilic inflammation. Better knowledge and pharmacologic tools may also allow DGK to move from the laboratory bench to clinical trials

Physiological Signaling and Structure of the HGF Receptor MET

The \u201chepatocyte growth factor\u201d also known as \u201cscatter factor\u201d, is a multifunctional cytokine with the peculiar ability of simultaneously triggering epithelial cell proliferation, movement and survival. The combination of those proprieties results in the induction of an epithelial to mesenchymal transition in target cells, fundamental for embryogenesis but also exploited by tumor cells during metastatization. The hepatocyte growth factor receptor, MET, is a proto-oncogene and a prototypical transmembrane tyrosine kinase receptor. Inhere we discuss the MET molecular structure and the hepatocyte growth factor driven physiological signaling which coordinates epithelial proliferation, motility and morphogenesis

Childrens health, human capital accumulation, and R&D-based economic growth

We analyze the effects of childrens health on human capital accumulation and on long-run economic growth. For this purpose we design an R&D-based growth model in which the stock of human capital of the next generation is determined by parental education and health investments. We show that i) there is a complementarity between education and health: if parents want to have better educated children, they also raise health investments and vice versa; ii) parental health investments exert an unambiguously positive effect on long-run economic growth, iii) faster population growth reduces long-run economic growth. These results are consistent with the empirical evidence for modern economies in the twentieth century

Inter-individual variability and phenotypic plasticity : the effect of the environment on the biogeography, population structure, ecophysiology and reproduction of the sandhoppers Talorchestia capensis and Africorchestia quadrispinosa

Climatic envelope models focus on the climatic variables affecting species or species assemblages, and are important tools to investigate the effect of climate change on their geographical ranges. These models have largely been proposed in order to make successful predictions on species‘ persistence, determining which variables are likely to induce range expansion, contraction, or shifting. More recent models, including the ability and the cost for individuals to respond promptly to an environmental stimulus, have revealed that species may express phenotypic plasticity able to induce adaptation to the new environment. Consequently, understanding how species evolve to a changing climate is fundamental. From this perspective, investigating intraspecific responses to an environmental variable may contribute to better understanding and prediction of the effect of climate change on the geographical range and evolution of species, particularly in the case of widespread species. In this context, the present study aimed at establishing how environmental variables (focussing mainly on temperature) may have contributed to shape the spatial distribution, physiology, reproductive biology and connectivity of two species of Southern African sandhoppers (Talorchestia capensis and Africorchestia quadrispinosa, Amphipoda, Talitridae). Most of the work was carried out on T. capensis, due to its widespread spatial distribution. A first investigation of the biogeography of T. capensis and A. quadrispinosa, revealed that, for both species, spatial patterns of abundance, size and sex ratio were not explained by the Abundant Centre Hypothesis (greater abundance at the core of a spatial range), but rather guided by bio-physical forces. Precisely, the abundance of sandhoppers was driven by the morphodynamic state of the beach, salinity and temperatures, with strong differentiation among sites that reflected local environmental conditions. In support of these findings, strong population structure in the genetics of T. capensis was found (three main groups) when investigating its phylogeography and genetic connectivity. Although such defined structure may suggests cryptic speciation, the concomitant within-population variation in the COX1 region of mtDNA, also highlighted the importance of individual genetic variability. High individual variability was also found in the response of T. capensis to temperature, both in its physiology (thermal plasticity) and its reproductive biology (maternal effects). Since temperature is one of the main variables affecting the coastal marine systems of southern Africa and the metabolism of animals in general, its effect on the physiology and reproduction of T. capensis was therefore investigated. Thermal responses to increasing/decreasing temperatures were assessed for separated populations of T. capensis. Individual variability was reported in the oxygen consumption of T. capensis in response to temperature (high variation around the means, especially for increasing temperatures). Among population differences in thermal sensitivity were significantly correlated with air temperature variability experienced over the past 23 years, highlighting the importance of historical temperature fluctuations to the current thermal physiology of these sandhoppers. Temperature also had an important effect on the reproductive plasticity of T. capensis. Different temperatures induced mothers to adjust the size of their offspring (i.e. egg size), with larger eggs produced at lower temperatures. Interestingly, females showed strongly significant among individual variation in the size of the eggs. Given the importance of understanding rapid responses of organisms to climate change and considering the fundamental role played by phenotypic plasticity in evolution, the overall study revealed the significance of individual plasticity and variability in response to the environment and highlighted its importance. Particularly, studying the thermal physiology of separated populations and understanding within population reproductive plasticity in response to temperature, helped to clarify how differences among individual responses have important consequences at the population level, possibly explaining the widespread distribution of T. capensis

Environmental domains and range-limiting mechanisms: testing the Abundant Centre Hypothesis using southern African sandhoppers

Predicting shifts of species geographical ranges is a fundamental challenge for conservation ecologists given the great complexity of factors involved in setting range limits. Distributional patterns are frequently modelled to “simplify” species responses to the environment, yet the central mechanisms that drive a particular pattern are rarely understood. We evaluated the distributions of two sandhopper species (Crustacea, Amphipoda, Talitridae), Talorchestia capensis and Africorchestia quadrispinosa along the Namibian and South African coasts, encompassing three biogeographic regions influenced by two different oceanographic systems, the Benguela and Agulhas currents. We aimed to test whether the Abundant Centre Hypothesis (ACH) can explain the distributions of these species’ abundances, sizes and sex ratios and examined which environmental parameters influence/drive these distributions. Animals were collected during a once-off survey at 29 sites over c.3500 km of coastline. The ACH was tested using a non-parametric constraint space analysis of the goodness of fit of five hypothetical models. Distance Based Linear Modelling (DistLM) was performed to evaluate which environmental traits influenced the distribution data. Abundance, size and sex ratio showed different patterns of distribution. A ramped model fitted the abundance (Ramped North) and size (Ramped South) distribution for A. quadrispinosa. The Inverse Quadratic model fitted the size distribution of T. capensis. Beach slope, salinity, sand temperature and percentage of detritus found on the shore at the time of collection played important roles in driving the abundance of A. quadrispinosa. T. capensis was mainly affected by salinity and the morphodynamic state of the beach. Our results provided only some support for the ACH predictions. The DistLM confirmed that the physical state of the beach is an important factor for sandy beach organisms. The effect of salinity and temperature suggest metabolic responses to local conditions and a role in small to mesoscale shifts in the range of these populations

VORAQUE: RANGE QUERY IN RETI P2P

La tesi in questione tratta problematiche relative alla gestione e risoluzione di range query in un sistema P2P la cui rete di overlay assume la struttura definita dai diagrammi di Voronoi. L'instradamento dei messaggi tra i nodi avviene tramite algoritmi di routing greedy e compass. Viene infine presentato un caso di studio che dimostra l'applicabilità del lavoro sviluppat