Kiwifruit bud release from dormancy: effect of exogenous cytokinins

A new formulate containing citokinins, that is commercialized as Cytokin, has been introduced as dormancy breaking agents. During a three-years study, Cytokin was applied at different concentrations and application times in two producing areas of the Emilia-Romagna region to verify its efficacy as a DBA. Cytokin application increased the bud break and showed a lateral flower thinning effect. Moreover, treated vines showed an earlier and more uniform flowering as compared to control ones. Results obtained on the productive performance revealed a constant positive effect in the fruit fresh weight at harvest. Moreover, Cytokin did not cause any phytotoxicity even at the highest concentrations. Starting from the field observation, which suggested the involvement of cytokinins in kiwifruit bud release from dormancy, 6-BA was applied in open field condition and molecular and histological analyses were carried out in kiwifruit buds collected starting from the endo dormant period up to complete bud break to compare the natural occurring situation to the one induced by exogenous cytokinin application. In details, molecular analyses were set up on to verify the expression of genes involved in the reactivation of cell cycle: cyclin D3, histone H4, cyclin-dependent kinase B, as well as of others which are known to be up regulated during bud release in other species, i.e.isopenteniltransferases (IPTs), which catalyze the first step in the CK biosynthesis, and sucrose synthase 1 and A, which are involved in the sugar supplied. Moreover, histological analyses of the cell division rate in kiwifruit bud apical meristems were performed. These analyses showed a reactivation of the cell divisions during bud release and changes in the expression level of the investigated genes.

Peak-to-Peak Output Current Ripple Analysis in Multiphase and Multilevel Inverters

Analysis of the peak-to-peak output current ripple amplitude for multiphase and multilevel inverters is presented in this PhD thesis. The current ripple is calculated on the basis of the alternating voltage component, and peak-to-peak value is defined by the current slopes and application times of the voltage levels in a switching period. Detailed analytical expressions of peak-to-peak current ripple distribution over a fundamental period are given as function of the modulation index. For all the cases, reference is made to centered and symmetrical switching patterns, generated either by carrier-based or space vector PWM. Starting from the definition and the analysis of the output current ripple in three-phase two-level inverters, the theoretical developments have been extended to the case of multiphase inverters, with emphasis on the five- and seven-phase inverters. The instantaneous current ripple is introduced for a generic balanced multiphase loads consisting of series RL impedance and ac back emf (RLE). Simplified and effective expressions to account for the maximum of the output current ripple have been defined. The peak-to-peak current ripple diagrams are presented and discussed. The analysis of the output current ripple has been extended also to multilevel inverters, specifically three-phase three-level inverters. Also in this case, the current ripple analysis is carried out for a balanced three-phase system consisting of series RL impedance and ac back emf (RLE), representing both motor loads and grid-connected applications. The peak-to-peak current ripple diagrams are presented and discussed. In addition, simulation and experimental results are carried out to prove the validity of the analytical developments in all the cases. The cases with different phase numbers and with different number of levels are compared among them, and some useful conclusions have been pointed out. Furthermore, some application examples are given.

Synthesis and application of new ion-tagged ligands and organocatalysts

We report the synthesis and application of some ion-tagged catalysts in organometallic catalysis and organocatalysis. With the installation of an ionic group on the backbone of a known catalyst, two main effects are generally obtained. i) a modification of the solubility of the catalyst: if judicious choice of the ion pair is made, the ion-tag can confer to the catalyst a solubility profile suitable for catalyst recycling. ii) the ionic group can play a non-innocent role in the process considered: if stabilizing interaction between the ionic group and the developing charges in the transition state are established, the reaction can speed up. We describe the use of ion-tagged diphenylprolinol as Zn ligand. The chiral ligand grafted onto an ionic liquid (IL) was recycled 10 times with no loss of reactivity and selectivity, when it was employed in the first example of enantioselective addition of ZnEt2 to aldehydes in ILs. An ammonium-tagged phosphine displayed the capability to stabilize Pd catalysts for the Suzuki reaction in ILs. The ionic phase was recycled 6 times with no detectable loss of activity and very low Pd leaching in the organic phase. This catalytic system was also employed for the functionalization of the challenging substrate 5,11-dibromotetracene. In the field of organocatalysis, we prepared two ion-tagged derivatives of the McMillan imidazolidinone. The results of the asymmetric Diels-Alder reaction between trans-cinnamaldehyde and cyclopentadiene exhibited great dependence on the position and nature of the ionic group. Finally, when O-TMS-diphenylprolinol was tagged with an imidazolium ion, exploiting a silyl ether linker, an efficient catalyst for the asymmetric addition of aldehydes to nitroolefins was achieved. The catalyst displayed enhanced reactivity and the same high level of selectivity of the untagged parent catalyst and it could be employed in a wide range of reaction conditions, included use of water as solvent.

Development of oil spill detection techniques for satellite optical sensors and their application to monitor oil spill discharge in Mediterranean sea

Satellite remote sensing has proved to be an effective support in timely detection and monitoring of marine oil pollution, mainly due to illegal ship discharges. In this context, we have developed a new methodology and technique for optical oil spill detection, which make use of MODIS L2 and MERIS L1B satellite top of atmosphere (TOA) reflectance imagery, for the first time in a highly automated way. The main idea was combining wide swaths and short revisit times of optical sensors with SAR observations, generally used in oil spill monitoring. This arises from the necessity to overcome the SAR reduced coverage and long revisit time of the monitoring area. This can be done now, given the MODIS and MERIS higher spatial resolution with respect to older sensors (250-300 m vs. 1 km), which consents the identification of smaller spills deriving from illicit discharge at sea. The procedure to obtain identifiable spills in optical reflectance images involves removal of oceanic and atmospheric natural variability, in order to enhance oil-water contrast; image clustering, which purpose is to segment the oil spill eventually presents in the image; finally, the application of a set of criteria for the elimination of those features which look like spills (look-alikes). The final result is a classification of oil spill candidate regions by means of a score based on the above criteria.

Biomaterials for Clinical Application in Endodontics

Endodontic therapy consists in the management of several tissues such as pulp tissue, periodontal tissue, periapical bone and dentine. These tissues are often contaminated by blood, periapical exudates and biological fluids. An ideal orthograde or retrograde filling material should be non toxic, noncarcinogenic, nongenotoxic, biocompatible with the host tissues, insoluble in tissue fluids, and dimensionally stable. Calcium-silicate MTA based cements own many of these ideal characteristics, but the long setting time, the non-easy handling and the lack of mechanical properties at early times are few drawbacks which may complicate the clinical application. The aim of this study was to investigate the chemical, physical and biological properties of calcium-silicate MTA cements in order to improve the mechanical properties and the handling keeping the biological characteristics unchanged. Chemical and physical properties such as setting time, solubility, water-uptake, ion release, sealing ability were investigated according the ISO and ADA specifications. The bioactivity (ability to produce apatite nano-sferulities) of MTA cements were evaluated using ESEM/EDX, micro-Raman and ATR/FTIR spettroscopy.

Farmacocinetica della buprenorfina, e del suo metabolita norbuprenorfina, somministrata come infusione costante nel periodo post-operatorio in cagne sane sottoposte ad ovariectomia

Il dolore non è solo una conseguenza della malattia ma un fattore patogeno che è di per se stesso in grado di perpetuare il danno all’organismo. Il suo trattamento non è quindi solo un atto di umanità ma un contributo ad arrestare la malattia e restituire la salute al paziente. Tra i farmaci più popolari per la terapia del dolore negli animali da affezione si trova la buprenorfina. Questa molecola viene impiegata con successo da anni nel cane e nel gatto per motivi riconducibili, oltre che alla sua efficacia (la sua potenza è diverse volte quella della morfina), alla lunga durata d’azione e alla scarsità degli effetti collaterali. Nonostante l’ampia diffusione e longevità del suo utilizzo, però, sappiamo poco della farmacocinetica di questa molecola negli animali da affezione; i dosaggi clinicamente impiegati sono di fatto estrapolati dagli studi nell’uomo oppure basati su semplici osservazioni degli effetti; i pochi dati farmacocinetici ottenuti nel cane fanno riferimento a singoli boli di dosi che non sempre corrispondono a quelle clinicamente impiegate. Nonostante la buprenorfina trovi il suo principale impiego nelle somministrazioni protratte a lungo (durante il periodo post-operatorio o la degenza ospedaliera) non è mai stato indagato il profilo farmacocinetico della molecola somministrata a boli ripetuti o come infusione continua. Il nostro studio si pone come obiettivo di indagare la farmacocinetica della buprenorfina somministrata come bolo di carico seguito da un’infusione costante a dosaggi considerati clinici in cani sani nel periodo post operatorio. Lo scopo ultimo è quello di sviluppare un protocollo per la somministrazione di questa molecola in modo prolungato in pazienti degenti ed addolorati per poi, in futuro, confrontare la somministrazione come infusione continua con i tradizionali boli ripetuti. Per lo studio sono state utilizzate giovani cagne adulte di taglia media o grande sottoposte ad intervento di ovariectomia.

Application of Pulsed Electric Fields for the Modulation of Chemico-Physical Properties of Different Foods

Pulsed electric field technology is one of the most attractive new non-thermal technology thanks to its lower energy consumption and short treatment times. It consists of an electric treatment of short duration (from several ns to several ms) with electric field strengths from 0.1 to 80 kV/cm that lead to an increase in the permeability of the cell membrane. In this PhD thesis, PEF technology was investigated with the aim of improving mass transfer in plant and animal foods by using it alone or in combination with conventional food processes. Different methods of evaluating electroporation for optimizing PEF processing parameters were investigated. In this respect, the degree of membrane permeabilization in plant and animal food matrices was investigated using electrical impedance spectroscopy, current-voltage measurements and magnetic resonance imaging. The research findings provided useful insights and calls for critical choice of electroporation assessment methods for the selection of adequate PEF treatment conditions. It was outlined that the effect of electroporation is highly dependent on the properties of the food matrix and secondary phenomena occurring in the cell structure undergoing PEF treatment, such as the water re-distribution in the tissue due to the exchange of fluids between intra- and extra-cellular environments. This study also confirmed the great potential of combining PEF technology with conventional food processes, with the main purpose of improving the quality of the food material and accelerating the kinetics of mass transfers, in both plant and animal tissues. Consistent reduction of acrylamide formation in potato crisps was achieved by monitoring key PEF process parameters and subsequent manufacturing steps. Kiwifruit snacks showed a significant reduction in drying kinetics when pre-treated with PEF, while their quality was well maintained. Finally, the research results showed that PEF pre-treatments can shorten the brine process as well as the rehydration kinetics of fish muscles.

Cleavage Politics in Changing Times. Political Realignment Processes in Western European Countries

The dissertation fits the political realignment literature and aims to pro-vide further insights into cleavage politics by investigating voting behaviour in the Western European countries’ national elections. In particular, the dis-sertation focuses on the class and value voting patterns and on the change of these patterns in different countries and over the course of time. Peculiar pro-cesses affected all Western European party systems: whilst the «traditional» cleavage theory accounts for National and Industrial revolutions, those pro-cesses assumed to constitute the «societal modernization» determined chang-es in electoral competitions that questioned the relevance of individuals’ so-cial positions to study electoral preferences. Since the associations between social positions and voting behaviour underpin the so-called political cleav-age, the dealignment perspective assumes them to have been eroding since the second half of the XX century. On the other hand, the realignment perspective argues that the cleavage theory still accounts for individuals’ vote choices: of the four «traditional» cleavages, this perspective hypothesizes new class vot-ing patterns and alignments between electoral preferences and a new line of conflict, that is based on values. The dissertation provides a theoretical ac-count of the realignment of the class cleavage and a new conceptualization of value voting. Then, class and value voting patterns are explored. The analyses employ European Social Survey data and detect general and country-specific patterns. The dissertation adopts a mediation perspective and aims to observe how class voting patterns change when controlling for value orientations. The results are provided with a sensitivity analysis, indeed two versions of the measures computed for value orientations are compared. The findings show that social class continues to affect voting behaviour and that value orienta-tions both mediate this effect and affect electoral preferences.

Application of Deep Learning techniques in the search for BSM Higgs bosons in the $\mu\mu$ final state in CMS

The Standard Model (SM) of particle physics predicts the existence of a Higgs field responsible for the generation of particles' mass. However, some aspects of this theory remain unsolved, supposing the presence of new physics Beyond the Standard Model (BSM) with the production of new particles at a higher energy scale compared to the current experimental limits. The search for additional Higgs bosons is, in fact, predicted by theoretical extensions of the SM including the Minimal Supersymmetry Standard Model (MSSM). In the MSSM, the Higgs sector consists of two Higgs doublets, resulting in five physical Higgs particles: two charged bosons $H^{\pm}$, two neutral scalars $h$ and $H$, and one pseudoscalar $A$. The work presented in this thesis is dedicated to the search of neutral non-Standard Model Higgs bosons decaying to two muons in the model independent MSSM scenario. Proton-proton collision data recorded by the CMS experiment at the CERN LHC at a center-of-mass energy of 13 TeV are used, corresponding to an integrated luminosity of $35.9\ \text{fb}^{-1}$. Such search is sensitive to neutral Higgs bosons produced either via gluon fusion process or in association with a $\text{b}\bar{\text{b}}$ quark pair. The extensive usage of Machine and Deep Learning techniques is a fundamental element in the discrimination between signal and background simulated events. A new network structure called parameterised Neural Network (pNN) has been implemented, replacing a whole set of single neural networks trained at a specific mass hypothesis value with a single neural network able to generalise well and interpolate in the entire mass range considered. The results of the pNN signal/background discrimination are used to set a model independent 95\% confidence level expected upper limit on the production cross section times branching ratio, for a generic $\phi$ boson decaying into a muon pair in the 130 to 1000 GeV range.

Escaping the debt trap: peripheral countries in prolonged debt crises and how to exit

This thesis is an interdisciplinary piece of academic research, situated within Critical Theory but engaging with other disciplines, mainly Political Economy and Politics, to tackle the topic at hand; sovereign debt crises. The thesis deals with the Problem of Debt and, more specifically, the Problem of Prolonged Sovereign Debt Crises, which is described in this thesis as the phenomenon of the “Debt Trap”. The specific question that will occupy us in this thesis is why countries appear unable to exit these prolonged debt crises. By exiting a debt crisis, we mean here a state of affairs in which a country has managed to render its debt sustainable, regain its democratic sovereignty, achieve economic recovery and, what is more, mitigate adverse effects of the crisis, especially in what human development, social inequality and poverty rates are concerned. This question is tackled through the use of an interdisciplinary approach that combines critical theory perspectives -which are grouped in two paradigms, the Subjectivity paradigm and the genealogies of Capitalism paradigm- with financialisation literature. The purpose is to form an interdisciplinary intellectual framework that will allow us to analyse with a critical perspective the two case studies of the Greek crisis from 2009 to 2015 and the Argentinean crisis from 1983 to 2005. The aim of the thesis is to develop a theoretical framework that allows us to deconstruct the various ideological approaches to these two particular cases of Debt traps, including neoclassical and neoliberal approaches, Conservative and Keynesian approaches and uncover the political, economic and class relation that underpin the prolonged crises that the two countries have experienced.

Chemical looping reforming from methane to syngas: investigation on CeO2 oxygen carrier lifetime and optimal process times

Emissions of CO2 are constantly growing since the beginning of industrial era. Interruption of the production of major emitters sectors (energy and agriculture) is not a viable way and reducing all the emission through carbon capture and storage (CCS) is not economically viable and little publicly accepted, therefore, it becomes fundamentals to take actions like retrofitting already developed infrastructure employing cleanest resources, modify the actual processes limiting the emissions, and reduce the emissions already present through direct air capture. The present thesis will deeply discuss the aspects mentioned in regard to syngas and hydrogen production since they have a central role in the market of energy and chemicals. Among the strategies discussed, greater emphasis is given to the application of looping technologies and to direct air capture processes, as they have been the main point of this work. Particularly, chemical looping methane reforming to syngas was studied with Aspen Plus thermodynamic simulations, thermogravimetric analysis characterization (TGA) and testing in a fixed bed reactor. The process was studied cyclically exploiting the redox properties of a Ce-based oxide oxygen carrier synthetized with a simple forming procedure. The two steps of the looping cycles were studied isothermally at 900 °C and 950° C with a mixture of 10 %CH4 in N2 and of 3% O2 in N2, for carrier reduction and oxidation, respectively. During the stay abroad, in collaboration with the EHT of Zurich, a CO2 capture process in presence of amine solid sorbents was investigated, studying the difference in the performance achievable with the use of contactors of different geometry. The process was studied at two concentrations (382 ppm CO2 in N2 and 5.62% CO2 in N2) and at different flow rates, to understand the dynamics of the adsorption process and to define the mass transfer limiting step.

Response times in computerized adaptive testing: a method for cheating detection

In the field of educational and psychological measurement, the shift from paper-based to computerized tests has become a prominent trend in recent years. Computerized tests allow for more complex and personalized test administration procedures, like Computerized Adaptive Testing (CAT). CAT, following the Item Response Theory (IRT) models, dynamically generates tests based on test-taker responses, driven by complex statistical algorithms. Even if CAT structures are complex, they are flexible and convenient, but concerns about test security should be addressed. Frequent item administration can lead to item exposure and cheating, necessitating preventive and diagnostic measures. In this thesis a method called "CHeater identification using Interim Person fit Statistic" (CHIPS) is developed, designed to identify and limit cheaters in real-time during test administration. CHIPS utilizes response times (RTs) to calculate an Interim Person fit Statistic (IPS), allowing for on-the-fly intervention using a more secret item bank. Also, a slight modification is proposed to overcome situations with constant speed, called Modified-CHIPS (M-CHIPS). A simulation study assesses CHIPS, highlighting its effectiveness in identifying and controlling cheaters. However, it reveals limitations when cheaters possess all correct answers. The M-CHIPS overcame this limitation. Furthermore, the method has shown not to be influenced by the cheaters’ ability distribution or the level of correlation between ability and speed of test-takers. Finally, the method has demonstrated flexibility for the choice of significance level and the transition from fixed-length tests to variable-length ones. The thesis discusses potential applications, including the suitability of the method for multiple-choice tests, assumptions about RT distribution and level of item pre-knowledge. Also limitations are discussed to explore future developments such as different RT distributions, unusual honest respondent behaviors, and field testing in real-world scenarios. In summary, CHIPS and M-CHIPS offer real-time cheating detection in CAT, enhancing test security and ability estimation while not penalizing test respondents.