Before It's Too Late: INGOs' Handling of Conflict Risk in South Sudan

What do international non-governmental organisations (INGOs) do before and during the escalation of conflicts? The academic literature primarily focuses on these organisations' behaviour during an evident crisis rather than on how they anticipate the escalation of conflicts, assess the situation in which they find themselves, and decide on strategies to cope with the possibility of upcoming violence. Such lopsided focus persists despite calls for INGOs to become more proactive in managing their programmes and their staff members' safety. Mindful of this imbalance, the present study provides a causal explanation of how decision-makers in INGOs anticipate and react to the risk of low-level violence escalating into full-blown conflicts. This thesis aims to explain these actors' behaviour by presenting it as a two�step process involving how INGOs conduct risk assessments and how they turn these assessments into decisions. The study performs a structured, focused comparison of seven INGOs operating in South Sudan before the so-called Juba Clashes of 7 July 2016. Based on an analytical framework of INGO decision�making stemming from political risk analysis, organisational decision-making theory and conflict studies literature, the study reconstructs decision-making via process-tracing combined with mixed methods of data collection.

Trajectory planning of single and dual-arm robots for time-optimal handling of liquids and objects

This Thesis studies the optimal control problem of single-arm and dual-arm serial robots to achieve the time-optimal handling of liquids and objects. The first topic deals with the planning of time-optimal anti-sloshing trajectories of an industrial robot carrying a cylindrical container filled with a liquid, considering 1-dimensional and 2-dimensional planar motions. A technique for the estimation of the sloshing height is presented, together with its extension to 3-dimensional motions. An experimental validation campaign is provided and discussed to assess the thoroughness of such a technique. As far as anti-sloshing trajectories are concerned, 2-dimensional paths are considered and, for each one of them, three constrained optimizations with different values of the sloshing-height thresholds are solved. Experimental results are presented to compare optimized and non-optimized motions. The second part focuses on the time-optimal trajectory planning for dual-arm object handling, employing two collaborative robots (cobots) and adopting an admittance-control strategy. The chosen manipulation approach, known as cooperative grasping, is based on unilateral contact between the cobots and the object, and it may lead to slipping during motion if an internal prestress along the contact-normal direction is not prescribed. Thus, a virtual penetration is considered, aimed at generating the necessary internal prestress. The stability of cooperative grasping is ensured as long as the exerted forces on the object remain inside the static-friction cone. Constrained-optimization problems are solved for 3-dimensional paths: the virtual penetration is chosen among the control inputs of the problem and friction-cone conditions are treated as inequality constraints. Also in this case experiments are presented in order to prove evidence of the firm handling of the object, even for fast motions.

Nonlinear/electromagnetic co-simulation of microwaves and millimeter-waves links

The Ph.D. thesis describes the simulations of different microwave links from the transmitter to the receiver intermediate-frequency ports, by means of a rigorous circuit-level nonlinear analysis approach coupled with the electromagnetic characterization of the transmitter and receiver front ends. This includes a full electromagnetic computation of the radiated far field which is used to establish the connection between transmitter and receiver. Digitally modulated radio-frequency drive is treated by a modulation-oriented harmonic-balance method based on Krylov-subspace model-order reduction to allow the handling of large-size front ends. Different examples of links have been presented: an End-to-End link simulated by making use of an artificial neural network model; the latter allows a fast computation of the link itself when driven by long sequences of the order of millions of samples. In this way a meaningful evaluation of such link performance aspects as the bit error rate becomes possible at the circuit level. Subsequently, a work focused on the co-simulation an entire link including a realistic simulation of the radio channel has been presented. The channel has been characterized by means of a deterministic approach, such as Ray Tracing technique. Then, a 2x2 multiple-input multiple-output antenna link has been simulated; in this work near-field and far-field coupling between radiating elements, as well as the environment factors, has been rigorously taken into account. Finally, within the scope to simulate an entire ultra-wideband link, the transmitting side of an ultrawideband link has been designed, and an interesting Front-End co-design technique application has been setup.

Molecular mechanisms involved in the pathogenesis of beet soil-borne viruses.

The genus Benyvirus includes the most important and widespread sugar beet viruses transmitted through the soil by the plasmodiophorid Polymyxa betae. In particular Beet necrotic yellow vein virus (BNYVV), the leading infectious agent that affects sugar beet, causes an abnormal rootlet proliferation known as rhizomania. Beet soil-borne mosaic virus (BSBMV) is widely distributed in the United States and, up to date has not been reported in others countries. My PhD project aims to investigate molecular interactions between BNYVV and BSBMV and the mechanisms involved in the pathogenesis of these viruses. BNYVV full-length infectious cDNA clones were available as well as full-length cDNA clones of BSBMV RNA-1, -2, -3 and -4. Handling of these cDNA clones in order to produce in vitro infectious transcripts need sensitive and expensive steps, so I developed agroclones of BNYVV and BSBMV RNAs, as well as viral replicons allowing the expression of different proteins. Chenopodium quinoa and Nicotiana benthamiana plants have been infected with in vitro transcripts and agroclones to investigate the interaction between BNYVV and BSBMV RNA-1 and -2 and the behavior of artificial viral chimeras. Simultaneously I characterized BSBMV p14 and demonstrated that it is a suppressor of post-transcriptional gene silencing sharing common features with BNYVV p14.

Tailoring properties and functionalities of TiO2 and Ag nanoparticles involved in surfaces engineering processes

The functionalization of substrates through the application of nanostructured coatings allows to create new materials, with enhanced properties. In this work, the development of self-cleaning and antibacterial textiles, through the application of TiO2 and Ag based nanostructured coatings was carried out. The production of TiO2 and Ag functionalized materials was achieved both by the classical dip-padding-curing method and by the innovative electrospinning process to obtain nanofibers doped with nano-TiO2 and nano-Ag. In order to optimize the production of functionalized textiles, the study focused on the comprehension of mechanisms involved in the photocatalytic and antibacterial processes and on the real applicability of the products. In particular, a deep investigation on the relationship between nanosol physicochemical characteristics, nanocoating properties and their performances was accomplished. Self-cleaning textiles with optimized properties were obtained by properly purifying and applying commercial TiO2 nanosol while the studies on the photocatalytic mechanism operating in self-cleaning application demonstrated the strong influence of hydrophilic properties and of interaction surface/radicals on final performance. Moreover, a study about the safety in handling of nano-TiO2 was carried out and risk remediation strategies, based on “safety by design” approach, were developed. In particular, the coating of TiO2 nanoparticles by a SiO2 shell was demonstrated to be the best risk remediation strategy in term of biological response and preserving of photoreactivity. The obtained results were confirmed determining the reactive oxygen species production by a multiple approach. Antibacterial textiles for biotechnological applications were also studied and Ag-coated cotton materials, with significant anti-bacterial properties, were produced. Finally, composite nanofibers were obtained merging biopolymer processing and sol-gel techniques. Indeed, electrospun nanofibers embedded with TiO2 and Ag NPs, starting from aqueous keratin based formulation were produced and the photocatalytic and antibacterial properties were assessed. The results confirmed the capability of electrospun keratin nanofibers matrix to preserve nanoparticle properties.