Innovation in aquaculture. Modeling the adoption and implementation processes of innovations in the Italian aquaculture sector

Since the turn of the century, fisheries have maintained a steady growth rate, while aquaculture has experienced a more rapid expansion. Aquaculture can offer EU consumers more diverse, healthy, and sustainable food options, some of which are more popular elsewhere. To develop the sector, the EU is investing heavily. The EU supports innovative projects that promote the sustainable development of seafood sectors and food security. Priority 3 promotes sector development through innovation dissemination. This doctoral dissertation examined innovation transfer in the Italian aquaculture sector, specifically the adoption of innovative tools, using a theoretical model to better understand the complexity of these processes. The work focused on innovation adoption, emphasising that it is the end of a well-defined process. The Awareness Knowledge Adoption Implementation Effectiveness (AKAIE) model was created to better analyse post-adoption phases and evaluate technology adoption implementation and impact. To identify AKAIE drivers and barriers, aquaculture actors were consulted. "Perceived complexity"—barriers to adoption that are strongly influenced by contextual factors—has been used to examine their perspectives (i.e. socio-economic, institutional, cultural ones). The new model will contextualise the sequence based on technologies, entrepreneur traits, corporate and institutional contexts, and complexity perception, the sequence's central node. Technology adoption can also be studied by examining complexity perceptions along the AKAIE sequence. This study proposes a new model to evaluate the diffusion of a given technology, offering the policy maker the possibility to be able to act promptly across the process. The development of responsible policies for evaluating the effectiveness of innovation is more necessary than ever, especially to orient strategies and interventions in the face of major scenarios of change.

Essays on Innovative Activity and the Protection of Innovations

This dissertation looks at three widely accepted assumptions about how the patent system works: patent documents disclose inventions; this disclosure happens quickly, and patent owners are able to enforce patents. The first chapter estimates the effect of stronger trade secret protection on the number of patented innovations. When firms find it easier to protect business information, there is less need for patent protection, and accordingly less need for the disclosure of technical information that is required by patent law. The novel finding is that when it is easier to keep innovations, there is not only a reduction in the number of patents but also a sizeable reduction in disclosed knowledge per patent. The chapter then shows how this endogeneity of the amount of knowledge per patent can affect the measurement of innovation using patent data. The second chapter develops a game-theoretic model to study how the introduction of fee-shifting in US patent litigation would influence firms’ patenting propensities. When the defeated party to a lawsuit has to bear not only their own cost but also the legal expenditure of the winning party, manufacturing firms in the model unambiguously reduce patenting, with small firms affected the most. For fee-shifting to have the same effect as in Europe, the US legal system would require shifting of a much smaller share of fees. Lessons from European patent litigation may, therefore, have only limited applicability in the US case. The third chapter contains a theoretical analysis of the influence of delayed disclosure of patent applications by the patent office. Such a delay is a feature of most patent systems around the world but has so far not attracted analytical scrutiny. This delay may give firms various kinds of strategic (non-)disclosure incentives when they are competing for more than a single innovation.

The drivers and implications of environmental innovations: European evidence at different levels of analysis

The present work is a collection of three essays devoted at understanding the determinants and implications of the adoption of environmental innovations EI by firms, by adopting different but strictly related schumpeterian perspectives. Each of the essays is an empirical analysis that investigates one original research question, formulated to properly fill the gaps that emerged in previous literature, as the broad introduction of this thesis outlines. The first Chapter is devoted at understanding the determinants of EI by focusing on the role that knowledge sources external to the boundaries of the firm, such as those coming from business suppliers or customers or even research organizations, play in spurring their adoption. The second Chapter answers the question on what induces climate change technologies, adopting regional and sectoral lens, and explores the relation among green knowledge generation, inducement in climate change and environmental performances. Chapter 3 analyzes the economic implications of the adoption of EI for firms, and proposes to disentangle EI by different typologies of innovations, such as externality reducing innovations and energy and resource efficient innovations. Each Chapter exploits different dataset and heterogeneous econometric models, that allow a better extension of the results and to overcome the limits that the choice of one dataset with respect to its alternatives engenders. The first and third Chapter are based on an empirical investigation on microdata, i.e. firm level data extracted from innovation surveys. The second Chapter is based on the analysis of patent data in green technologies that have been extracted by the PATSTAT and REGPAT database. A general conclusive Chapter will follow the three essays and will outline how each Chapter filled the research gaps that emerged, how its results can be interpreted, which policy implications can be derived and which are the possible future lines of research in the field.

Essays on social networks, altruism and information diffusion

This dissertation consists of three standalone articles that contribute to the economics literature concerning technology adoption, information diffusion, and network economics in one way or another, using a couple of primary data sources from Ethiopia. The first empirical paper identifies the main behavioral factors affecting the adoption of brand new (radical) and upgraded (incremental) bioenergy innovations in Ethiopia. The results highlight the importance of targeting different instruments to increase the adoption rate of the two types of innovations. The second and the third empirical papers of this thesis, use primary data collected from 3,693 high school students in Ethiopia, and shed light on how we should select informants to effectively and equitably disseminate new information, mainly concerning environmental issues. There are different well-recognized standard centrality measures that are used to select informants. These standard centrality measures, however, are based on the network topology---shaped only by the number of connections---and fail to incorporate the intrinsic motivations of the informants. This thesis introduces an augmented centrality measure (ACM) by modifying the eigenvector centrality measure through weighting the adjacency matrix with the altruism levels of connected nodes. The results from the two papers suggest that targeting informants based on network position and behavioral attributes ensures more effective and equitable (gender perspective) transmission of information in social networks than selecting informants on network centrality measures alone. Notably, when the information is concerned with environmental issues.

The firm. Techno-organizational changes, industrial relations and performances. An enquiry on Reggio Emilia local industrial system

It is not unknown that the evolution of firm theories has been developed along a path paved by an increasing awareness of the organizational structure importance. From the early “neoclassical” conceptualizations that intended the firm as a rational actor whose aim is to produce that amount of output, given the inputs at its disposal and in accordance to technological or environmental constraints, which maximizes the revenue (see Boulding, 1942 for a past mid century state of the art discussion) to the knowledge based theory of the firm (Nonaka & Takeuchi, 1995; Nonaka & Toyama, 2005), which recognizes in the firm a knnowledge creating entity, with specific organizational capabilities (Teece, 1996; Teece & Pisano, 1998) that allow to sustaine competitive advantages. Tracing back a map of the theory of the firm evolution, taking into account the several perspectives adopted in the history of thought, would take the length of many books. Because of that a more fruitful strategy is circumscribing the focus of the description of the literature evolution to one flow connected to a crucial question about the nature of firm’s behaviour and about the determinants of competitive advantages. In so doing I adopt a perspective that allows me to consider the organizational structure of the firm as an element according to which the different theories can be discriminated. The approach adopted starts by considering the drawbacks of the standard neoclassical theory of the firm. Discussing the most influential theoretical approaches I end up with a close examination of the knowledge based perspective of the firm. Within this perspective the firm is considered as a knowledge creating entity that produce and mange knowledge (Nonaka, Toyama, & Nagata, 2000; Nonaka & Toyama, 2005). In a knowledge intensive organization, knowledge is clearly embedded for the most part in the human capital of the individuals that compose such an organization. In a knowledge based organization, the management, in order to cope with knowledge intensive productions, ought to develop and accumulate capabilities that shape the organizational forms in a way that relies on “cross-functional processes, extensive delayering and empowerment” (Foss 2005, p.12). This mechanism contributes to determine the absorptive capacity of the firm towards specific technologies and, in so doing, it also shape the technological trajectories along which the firm moves. After having recognized the growing importance of the firm’s organizational structure in the theoretical literature concerning the firm theory, the subsequent point of the analysis is that of providing an overview of the changes that have been occurred at micro level to the firm’s organization of production. The economic actors have to deal with challenges posed by processes of internationalisation and globalization, increased and increasing competitive pressure of less developed countries on low value added production activities, changes in technologies and increased environmental turbulence and volatility. As a consequence, it has been widely recognized that the main organizational models of production that fitted well in the 20th century are now partially inadequate and processes aiming to reorganize production activities have been widespread across several economies in recent years. Recently, the emergence of a “new” form of production organization has been proposed both by scholars, practitioners and institutions: the most prominent characteristic of such a model is its recognition of the importance of employees commitment and involvement. As a consequence it is characterized by a strong accent on the human resource management and on those practices that aim to widen the autonomy and responsibility of the workers as well as increasing their commitment to the organization (Osterman, 1994; 2000; Lynch, 2007). This “model” of production organization is by many defined as High Performance Work System (HPWS). Despite the increasing diffusion of workplace practices that may be inscribed within the concept of HPWS in western countries’ companies, it is an hazard, to some extent, to speak about the emergence of a “new organizational paradigm”. The discussion about organizational changes and the diffusion of HPWP the focus cannot abstract from a discussion about the industrial relations systems, with a particular accent on the employment relationships, because of their relevance, in the same way as production organization, in determining two major outcomes of the firm: innovation and economic performances. The argument is treated starting from the issue of the Social Dialogue at macro level, both in an European perspective and Italian perspective. The model of interaction between the social parties has repercussions, at micro level, on the employment relationships, that is to say on the relations between union delegates and management or workers and management. Finding economic and social policies capable of sustaining growth and employment within a knowledge based scenario is likely to constitute the major challenge for the next generation of social pacts, which are the main social dialogue outcomes. As Acocella and Leoni (2007) put forward the social pacts may constitute an instrument to trade wage moderation for high intensity in ICT, organizational and human capital investments. Empirical evidence, especially focused on the micro level, about the positive relation between economic growth and new organizational designs coupled with ICT adoption and non adversarial industrial relations is growing. Partnership among social parties may become an instrument to enhance firm competitiveness. The outcome of the discussion is the integration of organizational changes and industrial relations elements within a unified framework: the HPWS. Such a choice may help in disentangling the potential existence of complementarities between these two aspects of the firm internal structure on economic and innovative performance. With the third chapter starts the more original part of the thesis. The data utilized in order to disentangle the relations between HPWS practices, innovation and economic performance refer to the manufacturing firms of the Reggio Emilia province with more than 50 employees. The data have been collected through face to face interviews both to management (199 respondents) and to union representatives (181 respondents). Coupled with the cross section datasets a further data source is constituted by longitudinal balance sheets (1994-2004). Collecting reliable data that in turn provide reliable results needs always a great effort to which are connected uncertain results. Data at micro level are often subjected to a trade off: the wider is the geographical context to which the population surveyed belong the lesser is the amount of information usually collected (low level of resolution); the narrower is the focus on specific geographical context, the higher is the amount of information usually collected (high level of resolution). For the Italian case the evidence about the diffusion of HPWP and their effects on firm performances is still scanty and usually limited to local level studies (Cristini, et al., 2003). The thesis is also devoted to the deepening of an argument of particular interest: the existence of complementarities between the HPWS practices. It has been widely shown by empirical evidence that when HPWP are adopted in bundles they are more likely to impact on firm’s performances than when adopted in isolation (Ichniowski, Prennushi, Shaw, 1997). Is it true also for the local production system of Reggio Emilia? The empirical analysis has the precise aim of providing evidence on the relations between the HPWS dimensions and the innovative and economic performances of the firm. As far as the first line of analysis is concerned it must to be stressed the fundamental role that innovation plays in the economy (Geroski & Machin, 1993; Stoneman & Kwoon 1994, 1996; OECD, 2005; EC, 2002). On this point the evidence goes from the traditional innovations, usually approximated by R&D investment expenditure or number of patents, to the introduction and adoption of ICT, in the recent years (Brynjolfsson & Hitt, 2000). If innovation is important then it is critical to analyse its determinants. In this work it is hypothesised that organizational changes and firm level industrial relations/employment relations aspects that can be put under the heading of HPWS, influence the propensity to innovate in product, process and quality of the firm. The general argument may goes as follow: changes in production management and work organization reconfigure the absorptive capacity of the firm towards specific technologies and, in so doing, they shape the technological trajectories along which the firm moves; cooperative industrial relations may lead to smother adoption of innovations, because not contrasted by unions. From the first empirical chapter emerges that the different types of innovations seem to respond in different ways to the HPWS variables. The underlying processes of product, process and quality innovations are likely to answer to different firm’s strategies and needs. Nevertheless, it is possible to extract some general results in terms of the most influencing HPWS factors on innovative performance. The main three aspects are training coverage, employees involvement and the diffusion of bonuses. These variables show persistent and significant relations with all the three innovation types. The same do the components having such variables at their inside. In sum the aspects of the HPWS influence the propensity to innovate of the firm. At the same time, emerges a quite neat (although not always strong) evidence of complementarities presence between HPWS practices. In terns of the complementarity issue it can be said that some specific complementarities exist. Training activities, when adopted and managed in bundles, are related to the propensity to innovate. Having a sound skill base may be an element that enhances the firm’s capacity to innovate. It may enhance both the capacity to absorbe exogenous innovation and the capacity to endogenously develop innovations. The presence and diffusion of bonuses and the employees involvement also spur innovative propensity. The former because of their incentive nature and the latter because direct workers participation may increase workers commitment to the organizationa and thus their willingness to support and suggest inovations. The other line of analysis provides results on the relation between HPWS and economic performances of the firm. There have been a bulk of international empirical studies on the relation between organizational changes and economic performance (Black & Lynch 2001; Zwick 2004; Janod & Saint-Martin 2004; Huselid 1995; Huselid & Becker 1996; Cappelli & Neumark 2001), while the works aiming to capture the relations between economic performance and unions or industrial relations aspects are quite scant (Addison & Belfield, 2001; Pencavel, 2003; Machin & Stewart, 1990; Addison, 2005). In the empirical analysis the integration of the two main areas of the HPWS represent a scarcely exploited approach in the panorama of both national and international empirical studies. As remarked by Addison “although most analysis of workers representation and employee involvement/high performance work practices have been conducted in isolation – while sometimes including the other as controls – research is beginning to consider their interactions” (Addison, 2005, p.407). The analysis conducted exploiting temporal lags between dependent and covariates, possibility given by the merger of cross section and panel data, provides evidence in favour of the existence of HPWS practices impact on firm’s economic performance, differently measured. Although it does not seem to emerge robust evidence on the existence of complementarities among HPWS aspects on performances there is evidence of a general positive influence of the single practices. The results are quite sensible to the time lags, inducing to hypothesize that time varying heterogeneity is an important factor in determining the impact of organizational changes on economic performance. The implications of the analysis can be of help both to management and local level policy makers. Although the results are not simply extendible to other local production systems it may be argued that for contexts similar to the Reggio Emilia province, characterized by the presence of small and medium enterprises organized in districts and by a deep rooted unionism, with strong supporting institutions, the results and the implications here obtained can also fit well. However, a hope for future researches on the subject treated in the present work is that of collecting good quality information over wider geographical areas, possibly at national level, and repeated in time. Only in this way it is possible to solve the Gordian knot about the linkages between innovation, performance, high performance work practices and industrial relations.

Characterization and modeling of the barrier properties in nanostructured systems

The object of the present study is the process of gas transport in nano-sized materials, i.e. systems having structural elements of the order of nanometers. The aim of this work is to advance the understanding of the gas transport mechanism in such materials, for which traditional models are not often suitable, by providing a correct interpretation of the relationship between diffusive phenomena and structural features. This result would allow the development new materials with permeation properties tailored on the specific application, especially in packaging systems. The methods used to achieve this goal were a detailed experimental characterization and different simulation methods. The experimental campaign regarded the determination of oxygen permeability and diffusivity in different sets of organic-inorganic hybrid coatings prepared via sol-gel technique. The polymeric samples coated with these hybrid layers experienced a remarkable enhancement of the barrier properties, which was explained by the strong interconnection at the nano-scale between the organic moiety and silica domains. An analogous characterization was performed on microfibrillated cellulose films, which presented remarkable barrier effect toward oxygen when it is dry, while in the presence of water the performance significantly drops. The very low value of water diffusivity at low activities is also an interesting characteristic which deals with its structural properties. Two different approaches of simulation were then considered: the diffusion of oxygen through polymer-layered silicates was modeled on a continuum scale with a CFD software, while the properties of n-alkanthiolate self assembled monolayers on gold were analyzed from a molecular point of view by means of a molecular dynamics algorithm. Modeling transport properties in layered nanocomposites, resulting from the ordered dispersion of impermeable flakes in a 2-D matrix, allowed the calculation of the enhancement of barrier effect in relation with platelets structural parameters leading to derive a new expression. On this basis, randomly distributed systems were simulated and the results were analyzed to evaluate the different contributions to the overall effect. The study of more realistic three-dimensional geometries revealed a prefect correspondence with the 2-D approximation. A completely different approach was applied to simulate the effect of temperature on the oxygen transport through self assembled monolayers; the structural information obtained from equilibrium MD simulations showed that raising the temperature, makes the monolayer less ordered and consequently less crystalline. This disorder produces a decrease in the barrier free energy and it lowers the overall resistance to oxygen diffusion, making the monolayer more permeable to small molecules.

Survey on the spirilar flora of Lagomorphs

Members of the genera Campylobacter and Helicobacter have been in the spotlight in recent decades because of their status as animals and/or humans pathogens, both confirmed and emerging, and because of their association with food-borne and zoonotic diseases. First observations of spiral shaped bacteria or Campylobacter-like organisms (CLO) date back to the end of the 19th century, however the lack of adequate isolation methods hampered further research. With the introduction of methods such as selective media and a filtration procedure during the 1970s led to a renewed interest in Campylobacter, especially as this enabled elucidation of their role in human hosts. On the other hand the classification and identification of these bacteria was troublesome, mainly because of the biochemical inertness and fastidious growth requirements. In 1991, the taxonomy of Campylobacter and related organisms was thoroughly revised, since this revision several new Campylobacter and Helicobacter species have been described. Moreover, thanks to the introduction of a polyphasic taxonomic practice, the classification of these novel species is well-founded. Indeed, a polyphasic approach was here followed for characterizing eight isolates obtained from rabbits epidemiologically not correlated and as a result a new Campylobacter species was proposed: Campylobacter cuniculorum (Chapter 1). Furthermore, there is a paucity of data regarding the occurrence of spiral shaped enteric flora in leporids. In order to define the prevalence both of this new species and other CLO in leporids (chapter 2), a total of 85 whole intestinal tracts of rabbits reared in 32 farms and 29 capture hares, epidemiologically not correlated, were collected just after evisceration at the slaughterhouse or during necroscopy. Examination and isolation methods were varied in order to increase the sensibility level of detection, and 100% of rabbit farms resulted positive for C. cuniculorum in high concentrations. Moreover, in 3.53% of the total rabbits examined, a Helicobacter species was detected. Nevertheless, all hares resulted negative both for Campylobacter or Helicobacter species. High prevalence of C. cuniculorum were found in rabbits, and in order to understand if this new species could play a pathological role, a study on some virulence determinants of C. cuniculorum was conducted (Chapter 3). Although this new species were able to adhere and invade, exert cytolethal distending toxin-like effects although at a low titre, a cdtB was not detected. There was no clear relationship between source of isolation or disease manifestation and possession of statistically significantly levels of particular virulence-associated factors although, cell adhesion and invasion occurred. Furthermore, antibiotic susceptibility was studied (chapter 4) in Campylobacter and in Escherichia coli strains, isolated from rabbits. It was possible to find acquired resistance of C. cuniculorum to enrofloxacin, ciprofloxacin and erytromycin. C. coli isolate was susceptible to all antimicrobial tested and moreover it is considered as a wild-type strain. Moreover, E. coli was found at low caecal concentration in rabbits and 30 phenotypes of antibiotic resistance were founded as well as the high rate of resistances to at least one antibiotic (98.1%). The majority of resistances were found from strains belonging to intensive farming system. In conclusion, in the course of the present study a new species isolated from rabbits was described, C. cuniculorum, and its high prevalence was established. Nevertheless, in hare samples no Campylobacter and Helicobacter species were detected. Some virulence determinants were further analyzed, however further studied are needed to understand the potential pathogenicity of this new species. On the other hand, antimicrobial susceptibility was monitored both in C. cuniculorum and indicator bacteria and acquired resistance was observed towards some antibiotics, indicating a possible role of rabbitries in the diffusion of antibiotic resistance. Further studies are necessary to describe and evaluate the eventual zoonotic role of Campylobacter cuniculorum.

Advances in understanding of osmotic dehydration and vacuum impregnation of fruits

Osmotic Dehydration and Vacuum Impregnation are interesting operations in the food industry with applications in minimal fruit processing and/or freezing, allowing to develop new products with specific innovative characteristics. Osmotic dehydration is widely used for the partial removal of water from cellular tissue by immersion in hypertonic (osmotic) solution. The driving force for the diffusion of water from the tissue is provided by the differences in water chemical potential between the external solution and the internal liquid phase of the cells. Vacuum Impregnation of porous products immersed in a liquid phase consist of reduction of pressure in a solid-liquid system (vacuum step) followed by the restoration of atmospheric pressure (atmospheric step). During the vacuum step the internal gas in the product pores is expanded and partially flows out while during the atmospheric step, there is a compression of residual gas and the external liquid flows into the pores (Fito, 1994). This process is also a very useful unit operation in food engineering as it allows to introduce specific solutes in the tissue which can play different functions (antioxidants, pH regulators, preservatives, cryoprotectants etc.). The present study attempts to enhance our understanding and knowledge of fruit as living organism, interacting dynamically with the environment, and to explore metabolic, structural, physico-chemical changes during fruit processing. The use of innovative approaches and/or technologies such as SAFES (Systematic Approach to Food Engineering System), LF-NMR (Low Frequency Nuclear Magnetic Resonance), GASMAS (Gas in Scattering Media Absorption Spectroscopy) are very promising to deeply study these phenomena. SAFES methodology was applied in order to study irreversibility of the structural changes of kiwifruit during short time of osmotic treatment. The results showed that the deformed tissue can recover its initial state 300 min after osmotic dehydration at 25 °C. The LF-NMR resulted very useful in water status and compartmentalization study, permitting to separate observation of three different water population presented in vacuole, cytoplasm plus extracellular space and cell wall. GASMAS techniques was able to study the pressure equilibration after Vacuum Impregnation showing that after restoration of atmospheric pressure in the solid-liquid system, there was a reminding internal low pressure in the apple tissue that slowly increases until reaching the atmospheric pressure, in a time scale that depends on the vacuum applied during the vacuum step. The physiological response of apple tissue on Vacuum Impregnation process was studied indicating the possibility of vesicular transport within the cells. Finally, the possibility to extend the freezing tolerance of strawberry fruits impregnated with cryoprotectants was proven.

Evaluation of Microbial Contamination in Bivalve Mollusks: Epidemiology and Diagnosis

Shellfish are filter-feeding organisms that can accumulate many bacteria and viruses. Considering that depuration procedures are not effective in removal of certain microorganisms, shellfish-borne diseases are frequent in many parts of the world, and their control must rely primarily on investigation of prevalence of human pathogens in shellfish and water environment. However, the diffusion of enteric viruses and Vibrio bacteria is not known in many geographical areas, for example in Sardinia, Italy. A survey aimed at investigating the prevalence of Norovirus (NoV), hepatitis A virus (HAV), V. parahaemolyticus, V. cholerae and V. vulnificus was carried out, analyzing both local and imported purified, non-purified and retail shellfish from North Italy and Sardinia. Shellfish from both areas were found contaminated by NoVs, HAV and Vibrio, including retail and purified animals. Molecular analysis evidenced different NoV genogroups and genotypes, including bovine NoVs, as well as pathogenic Vibrio strains, underlining the risk for shellfish consumers. However, also other approaches are needed to control the diffusion of shellfish-borne diseases. It was originally thought that enteric viruses are passively accumulated by shellfish. Recently, it was proven that NoVs bind to specific carbohydrate ligands in oysters, and various NoV strains are characterized by a different bioaccumulation pattern. To deepen the knowledge on this argument, a study was carried out, analyzing bioaccumulation of up to 8 different NoV strains in four different species of shellfish. Different bioaccumulation patterns were observed for each shellfish species and NoV strain used, potentially important in setting up effective shellfish purification protocols. Finally, a novel study of evaluation of viral contamination in shellfish from the French Atlantic coast was carried out following the passage of Xynthia tempest over Western Europe which caused massive destruction. Different enteric viruses were found over a one month period, evidencing the potential of these events of contaminating shellfish.

Physiological and structural aspects of fruit and vegetable mild processing

Over the past years fruit and vegetable industry has become interested in the application of both osmotic dehydration and vacuum impregnation as mild technologies because of their low temperature and energy requirements. Osmotic dehydration is a partial dewatering process by immersion of cellular tissue in hypertonic solution. The diffusion of water from the vegetable tissue to the solution is usually accompanied by the simultaneous solutes counter-diffusion into the tissue. Vacuum impregnation is a unit operation in which porous products are immersed in a solution and subjected to a two-steps pressure change. The first step (vacuum increase) consists of the reduction of the pressure in a solid-liquid system and the gas in the product pores is expanded, partially flowing out. When the atmospheric pressure is restored (second step), the residual gas in the pores compresses and the external liquid flows into the pores. This unit operation allows introducing specific solutes in the tissue, e.g. antioxidants, pH regulators, preservatives, cryoprotectancts. Fruit and vegetable interact dynamically with the environment and the present study attempts to enhance our understanding on the structural, physico-chemical and metabolic changes of plant tissues upon the application of technological processes (osmotic dehydration and vacuum impregnation), by following a multianalytical approach. Macro (low-frequency nuclear magnetic resonance), micro (light microscopy) and ultrastructural (transmission electron microscopy) measurements combined with textural and differential scanning calorimetry analysis allowed evaluating the effects of individual osmotic dehydration or vacuum impregnation processes on (i) the interaction between air and liquid in real plant tissues, (ii) the plant tissue water state and (iii) the cell compartments. Isothermal calorimetry, respiration and photosynthesis determinations led to investigate the metabolic changes upon the application of osmotic dehydration or vacuum impregnation. The proposed multianalytical approach should enable both better designs of processing technologies and estimations of their effects on tissue.

Quality of Service in Distributed Stream Processing for large scale Smart Pervasive Environments

The wide diffusion of cheap, small, and portable sensors integrated in an unprecedented large variety of devices and the availability of almost ubiquitous Internet connectivity make it possible to collect an unprecedented amount of real time information about the environment we live in. These data streams, if properly and timely analyzed, can be exploited to build new intelligent and pervasive services that have the potential of improving people's quality of life in a variety of cross concerning domains such as entertainment, health-care, or energy management. The large heterogeneity of application domains, however, calls for a middleware-level infrastructure that can effectively support their different quality requirements. In this thesis we study the challenges related to the provisioning of differentiated quality-of-service (QoS) during the processing of data streams produced in pervasive environments. We analyze the trade-offs between guaranteed quality, cost, and scalability in streams distribution and processing by surveying existing state-of-the-art solutions and identifying and exploring their weaknesses. We propose an original model for QoS-centric distributed stream processing in data centers and we present Quasit, its prototype implementation offering a scalable and extensible platform that can be used by researchers to implement and validate novel QoS-enforcement mechanisms. To support our study, we also explore an original class of weaker quality guarantees that can reduce costs when application semantics do not require strict quality enforcement. We validate the effectiveness of this idea in a practical use-case scenario that investigates partial fault-tolerance policies in stream processing by performing a large experimental study on the prototype of our novel LAAR dynamic replication technique. Our modeling, prototyping, and experimental work demonstrates that, by providing data distribution and processing middleware with application-level knowledge of the different quality requirements associated to different pervasive data flows, it is possible to improve system scalability while reducing costs.

Polymeric membranes for CO2 separation: effect of aging, humidity and facilitated transport

Polymeric membranes represent a promising technology for gas separation processes, thanks to low costs, reduced energy consumption and limited waste production. The present thesis aims at studying the transport properties of two membrane materials, suitable for CO2 purification applications. In the first part, a polyimide, Matrimid 5218, has been throughout investigated, with particular reference to the effect of thermal treatment, aging and the presence of water vapor in the gas transport process. Permeability measurements showed that thermal history affects relevantly the diffusion of gas molecules across the membrane, influencing also the stability of the separation performances. Subsequently, the effect of water on Matrimid transport properties has been characterized for a wide set of incondensable penetrants. A monotonous reduction of permeability took place at increasing the water concentration within the polymer matrix, affecting the investigated gaseous species to the same extent, despite the different thermodynamic and kinetic features. In this view, a novel empirical model, based on the Free Volume Theory, has been proposed to qualitatively describe the phenomenon. Moreover, according to the accurate representation of the experimental data, the suggested approach has been combined with a more rigorous thermodynamic tool (NELF Model), allowing an exhaustive description of water influence on the single parameters contributing to the gas permeation across the membrane. In the second part, the study has focused on the synthesis and characterization of facilitated transport membranes, able to achieving outstanding separation performances thanks to the chemical enhancement of CO2 permeability. In particular, the transport properties have been investigated for high pressure CO2 separation applications and specific solutions have been proposed to solve stability issues, frequently arising under such severe conditions. Finally, the effect of different process parameters have been investigated, aiming at the identification of the optimal conditions capable to maximize the separation performance.

Phenotypic and genotypic characterisation of antimicrobial resistance in Escherichia coli indicator of animal, food and human origin.

This thesis presents AMR phenotypic evaluation and whole genome sequencing analysis of 288 Escherichia coli strains isolated from different sources (livestock, companion animal, wildlife, food and human) in Italy. Our data reflects general resistance trends in Europe, reporting tetracycline, ampicillin, sulfisoxazole and aminoglycosides resistance as the most common phenotypic AMR profile among livestock, pets, wildlife and humans. Identification of human and animal (livestock and companion animal) AMR profiles in niches with a rare (fishery, mollusc) or absent (vegetable, wild animal, wild boar) direct exposure to antimicrobials, suggests widespread environmental pollution with ARGs conferring resistance to these antimicrobials. Phenotypic resistance to highest priority critically important antimicrobials was mainly observed in food-producing animals and related food such as rabbit, poultry, beef and swine. Discrepancies between AMR phenotypic pattern and genetic profile were observed. In particular, phenotypic aminoglycoside, cephalosporin, meropenem, colistin resistance and ESBL profile did not have a genetic explanation in different cases. This data could suggest the diffusion of new genetic variants of ARGs, associated to these antimicrobial classes. Generally, our collection shows a virulence profile typical of extraintestinal pathogenic Escherichia coli (ExPEC) pathotype. Different pandemic and emerging ExPEC lineages were identified, in particular in poultry meat (ST10; ST23; ST69, ST117; ST131). Rabbit was suggested as a source of ST20-ST40 potential hybrid pathogens. Wildlife carried a high average number (10) of VAGs (mostly associated to ExPEC pathotype) and different predominant ExPEC lineages (ST23, ST117, ST648), suggesting its possible involvement in maintenance and diffusion of virulence determinants. In conclusion, our study provides important knowledge related to the phenotypic/genetic AMR and virulence profiles circulating in E. coli in Italy. The role of different niches in AMR dynamics has been discussed. In particular, food-producing animals are worthy of continued investigation as a source of potential zoonotic pathogens, meanwhile wildlife might contribute to VAGs spread.

Innovation Diffusion and Biostimulant knowledge in Moroccan agriculture

Our study focused on Morocco investigating the dissemination of PBs amongst farmers belonging to the first pillar of the GMP, located in the Fès-Meknès region. As well as to assess how innovation adoption is influenced by the network of relationships that various farmers are involved in. We adopted an “ego network” approach to identify the primary stakeholders responsible for the diffusion of PBs. We collected data through “face-to-face” interviews with 80 farmers in April and May 2021. The data were processed with the aim of: 1) analysing the total number of main and specific topics discussed between egos and egos’ alters regarding the variation of some egos attributes; 2) analysing egos’ network characteristics using E-Net software, and 3) identifying the significant variables that influence farmers to access knowledge, use and reuse of PBs a Binary Logistic Regression (LR) was applied. The first result disclosed that the main PBs topics discussed were technical positioning, the need to use PBs, knowledge of PBs, and organic PBs. We noted that farmers have specific features: they have a high school diploma and a bachelor's degree; they are specialised in fruits and cereals farming, and they are managers and members of a professional organisation. The second result showed results of SNA: 1) PBs seem to become generally a common argument for farmers who have already exchanged fertiliser information with their alters; 2) we disclosed a moderate heterogeneity in the networks, farmers have access to information mainly from acquaintances and professionals, and 3) we revealed that networks have a relatively low density and alters are not tightly connected to each other. Farmers have a brokerage position in the networks controlling the flow of information about the PBs. LR revealed that both the farmers’ attributes and the networks’ characteristics influence growers to know, use and reuse PBs.

Understanding the role of microglial extracellular vesicles (EVs) in neuroinflammation spreading: an in vitro study

Neuroinflammation is a crucial pathogenic mechanism that commonly underlies most neurodegenerative diseases. Microglia, the immune cells of the brain, play a critical role that changes depending on the stage of neuropathology: at early phases of brain diseases microglia display the neuroprotective phenotype which is switched to the classically activated pro-inflammatory subtype at later stages, contributing to neurodegeneration. The microglial phenotypic shift is characterized by a change in the release of bioactive molecules both soluble and through extracellular vesicles. Our in vitro studies aim to understand whether different types of activation could determine change in vesicles content, in particular miRNAs, and whether this could influence the activation state of control microglial cells. Microglial polarization has been induced in two different in vitro models: N9, microglial murine cell line, have been treated by using LPS towards a proinflammatory/neurotoxic phenotype or ATP towards antinflammatory/neuroprotective status; HMC3, human microglial cell line, have been activated using IFN-+ATP. We demonstrated that conditioned media/exosomes obtained from donor microglia were able to promote a pro-inflammatory phenotype in control cells, leading us to prove the existence of a neuroinflammation spreading process mediated by extracellular vesicles of microglia with a crucial role of miRNAs. Increased expression of miRNA-34a observed in N9 model underlines a possible contribution in the diffusion of proinflammatory activation of microglia. Thus, we tried to downregulate miR-34a expression using cleaving sequences of anti-mir-34a DNAzyme delivered by DNA nanostructures aimed to confirm the involvement of miR-34a in microglia polarization towards the neurotoxic phenotype. In conclusion, this thesis work reveal a new inflammation spreading mechanism that involves release of vesicles containing specific cargos by donor polarized microglia, particularly miRNAs, able to influence the phenotypic shift in unpolarized microglia: this process deserves to be deeply investigated as potential therapeutic target to counteract neurodegenerative diseases.