VictorJuiz/thesis huggingface dataset:
Role and regulation of chemotaxis and motility in the Rhizobium-legume symbiosis
Keywords: rhizobia
Rhizobium leguminosarum
Rhizobia-legume symbiosis
motility
chemotaxis

Fertilisers are used to provide crop plants with essential nutrients such as nitrogen but with a high energy cost and detrimental environmental effects. The symbiosis of legumes with rhizobia exhibits none of these problems since the bacteria provide fixed nitrogen directly to the plant. Further understanding of the initiation of symbiosis may enable improvements to the farming of crop legumes and enable the same processes to be mimicked in engineered systems of other crops. Although motility and chemotaxis are known to be crucial for competitive plant root colonisation (the first stage of symbiosis), little is known about their importance after this stage. In this thesis, I aimed to describe the importance of chemotaxis and motility in sequential stages of symbiosis up to the generation of root nodules filled with nitrogen-fixing rhizobia. To this end, the chemotaxis and motility systems of the model rhizobia Rhizobium leguminosarum biovar viciae 3841 (Rlv3841) were characterised, in both free-living and plant-associated states.
Rlv3841 motility is driven by flagella rotation modulated by two chemotaxis systems, Che1 and Che2, that respond to signals sensed by chemoreceptors. In this work we found that Rlv3841 has a diverse set of chemoreceptors that enable the bacteria to sense and respond to a variety of chemical gradients, by both externally sensing in the periplasm and internally sensing metabolic state. We also found a novel system that halts the bacteria in response to high concentrations of TCA cycle intermediates independent of the chemotaxis systems. An inorganic phosphate uptake system (PstSCAB) and a putative methyltransferase (encoded by RL3464) were found to be critical to the response, although their downstream effectors were not identified. Finally, we characterised the importance of the chemotaxis and flagella systems of Rlv3841 at sequential stages of the symbiosis. This involved marking bacteria with luminescence, fluorescence and enzymatic activity and assaying the bacteria by optical imaging, flow cytometry and staining. We found that there are several critical stages in which chemotaxis and motility are essential and that these occur after the plant root has been colonised by the rhizobia. In particular, we found that Che1 and flagella are important for movement around the root and to root hair tips and that Che2 is involved in infection thread formation and bacteroid differentiation. Overall, this work improves our understanding of the chemotaxis and motility systems of Rlv3841 and their importance across the whole Rhizobium-legume symbiosis cycle.
Developing critical appraisal of systematic reviews reporting network meta-analysis
Keywords: systematic review
network meta-analysis
critical appraisal

The aim of the research presented in this thesis was to advance the critical appraisal of systematic reviews using network meta-analysis (NMA) methods for synthesis. My review of systematic reviews using NMA methodology for synthesis and their characteristics found a rapid increase in publication of such reviews between 2008 and 2012, which has since continued. My survey of the authors of these reviews identified standards for reporting such reviews that were consistent with those subsequently included in the 2015 PRISMA extension statement for reporting of NMA. My programme of research then moved on to summarise how evidence from synthesis using NMA was used in NICE clinical guidelines published or updated during 2015-16. This found that although NMA methods were used far less often than pair-wise meta-analysis, they were used or considered for nearly one quarter of the guidelines reviewed. However, recommendations in the guidelines were more often based on results of NMA conducted by the Guideline Development Group than on results from previously published systematic reviews using NMA methodology. This finding, and reservations expressed by authors in my survey, supported the need to identify a critical appraisal tool to help users identify the quality of systematic reviews that use NMA methodology. After my review of existing critical appraisal tools failed to identify one suitable for systematic reviews using NMA methods for synthesis, I constructed a new tool, using the CASP format and based on items contained in the most current and most widely used related tools. The new tool was tested for inter-rater reliability and the findings of that testing and those from other elements in this programme of research allow the thesis to conclude with implications and some recommendations for further optimisation and validation of the tool.
Studio sul mito nell’opera di Carlo Emilio Gadda
Keywords: Carlo Emilio Gadda
philosophy
myth

This thesis investigates mythopoesis in the works of the Milanese writer Carlo Emilio Gadda (1893-1973). It aims to contextualize the category of myth within the epistemological construction that underlies Gadda’s oeuvre.
The project consists of two sections. The first section (chs. 1-2) brings to light two original hermeneutic horizons of Gadda’s inquiry into myth: here, the philosophical essay Meditazione milanese (1928; 1974) marks the author’s conceptual transition, from the modules of psychologism and physiological Kantianism, to his exposure to 20th century epistemological debate. With regards to this period of transition, we hypothesized that an important and previously unappreciated role was played by the philosopher Antonio Banfi and the intellectuals of the Milanese circle that surrounded him (L. Anceschi; R. De Grada; E. Paci; E. Vittorini; G. Ferrata; A. Vigevani). This hypothesis was supported through the study of documents preserved in numerous archival collections.
Following from the first section’s discussion of Gadda’s philosophical turn, the second section of the project (chs. 3-4) analyzes the terms, modalities, and functionalities by which myth penetrates the author’s speculative sphere in two particular works: L’Adalgisa. Disegni milanesi (1944) and Eros e Priapo (1944-45; 1967). This section offers an in-depth critical analysis compared to traditional readings and sources on the two texts. It addresses the question of myth from different disciplinary coordinates: respectively, the socio-psycho-ethno-anthropological in L’Adalgisa, and the political-ideological in Eros e Priapo.
In an inextricable interplay between poetics and gnoseology, the theoretical framework that arises from this study demonstrates how myth is a means by which the author attempts to finalize his tormented exploration of the world. With it, he invents and perfects his psychology and elaborates a personal sociology and anthropology, reinvigorating, at the same time, the lines of a peculiar metaphysics.
Homogeneous catalysts for the ROCOP of CO2 and epoxides
Keywords: Homogeneous catalysis
Polymerisation

The ring-opening copolymerisation of carbon dioxide and epoxides, yielding aliphatic polycarbonates, is a useful means to valorise waste gas and to reduce pollution in polymer manufacturing. Key to the success of this polymerization is the catalyst controlling both rate and selectivity. This thesis details the synthesis, characterisation and application of various inorganic complexes as homogeneous catalysts for these copolymerisations. Two different classes of catalysts are examined: (1) Heterodinuclear complexes, combining Mg(II) and various first-row transition metal(II) elements, are investigated to understand the potential for bimetallic synergy. Overall, the thesis provides insight into catalyst mechanisms and future design options. (2) Mononuclear indium(III) complexes.
Chapter 1 contains a literature review of existing catalysts and mechanisms. It ends with an overview of the thesis aims and rationale for the selection of the catalysts.
Chapter 2 provides an overview of selected material characterisation methods relevant to both the inorganic catalysts and the polymerisation catalysis.
Chapter 3 compares catalysis using a series of heterodinuclear complexes of the form MgM where M = Mg(II), Cr(II), Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II). The most active catalysts are MgFe or MgCo ‒ both show very high activity and selectivity for cyclohexene oxide / carbon dioxide ROCOP. The catalysts are also active using vinyl cyclohexene oxide, cyclopentene oxide and 3,4-epoxytetrahydrofuran/CO2 and for norbornene anhydride/CHO.
Chapter 4 describes the synthesis and characterisation of a series of salen and salan In(III) catalysts. The influence of electron donation of both the imine backbone (C=N, C‒N and C‒NMe) and para-phenolate position (tBu, OMe and Me) upon the catalysis are compared. The optimum catalysis conditions are under 40 bar carbon dioxide pressure and with a PPNCl cocatalyst.
Chapter 5 provides and overall conclusion and outlook to the research presented in this thesis.
Chapter 6 describes the experimental methods and techniques used in this thesis.
Towards molecular simulations of glycans, glycoproteins, and membrane-membrane interactions
Keywords: glycoprotein
biomembrane
glycan
simulation
glycosylation
membrane
MD simulation
glycolipid
CGMD
coarse-grained
molecular dynamics

Close apposition of membranes is a frequent occurrence in biological systems,and one of considerable physiological and pathological significance. The geo-metric and compositional complexity of such associations, and in some casestheir transient and/or rare occurrence, makes them challenging to study ex-perimentally, and necessitates a multidisciplinary approach to their investiga-tion. Molecular dynamics (MD) simulations have considerable potential toform part of the toolkit for studying membrane interactions, being able to pro-vide molecular-level insight into the time-dependent behaviour of biologicalsystems. However, there at present is no standard approach to prepare and sim-ulate membrane-membrane interactions for MD simulations. In this work, Ipresent progress towards the development of methods that could prove valuablein preparing simulation systems for this purpose.
The role of the United States in the European Union's decision-making on security policy: 2001-2005
Keywords: security
European Security and Defense Policy
NATO
European Union
embargo
Galileo Satellite System
arms control
United States

At the start of the 21st century, the European Union had entered the realm of security policy, gaining legal competence and building institutional structures. Yet it was not the only actor or institution in European security. Its constituent member states had independent security policies; most were part of the formal institution of the North Atlantic Treaty Organization; and all existed within the informal institution of the transatlantic security community. The United States was the most powerful actor in the two latter institutions and had longstanding bilateral ties to EU member states. Given the overlapping institutional nature of this field and the United States' unique pertinence to European security, it seems possible that the US, although a non-member state, might have causal significance when the EU deliberates security policy. This thesis seeks to investigate this possibility and to identify what role the United States may play in the EU's decision-making process. It does so using a typology of roles – accommodator, entrepreneur, spoiler and veto player – created from examples in European and institutional literature and grounded in the history of European security since the end of the Cold War. The American role is explored with three case studies of EU security debates from 2001 to 2005: the discussion over EU security structure prompted by the April 29, 2003, Mini-Summit on European Security and Defense Policy; the political agreements surrounding the creation of the Galileo Global Navigation Satellite System; and the dispute over lifting the EU's arms embargo on the People's Republic of China. In each case study, the European Union is a significant force and its internal dynamics are difficult for the United States to penetrate. However, in each episode, the US is ultimately a causally significant player in the EU's decision-making process, most resembling, according to the typology, a veto player.
Micro- to nano-scale characterisation of the morphology, structure and composition of γ΄ precipitate populations in a new nickel-base superalloy
Keywords: kinetics
precipitate size distribution
neutron diffraction
dissolution
precipitation
γ΄ precipitates
HR-STEM
heat treatment
growth
nickel-base superalloys

The emerging need to reduce CO2 emissions, while simultaneously improving the efficiency of aeroengines drives the continuous quest for new nickel-base superalloy formulations with improved thermal and mechanical properties. Aiming to expand the operational limits of superalloys outside the current envelope, higher γ′ volume fraction alloys have been developed considering the fundamental role of γ′ precipitation in the high temperature mechanical performance. The main objective of this study has been to investigate the multimodal distribution of the γ′ precipitate populations in a new high γ′ content nickel-base superalloy. Advanced experimental techniques were employed providing complementary information about the γ′ precipitate phase not only at the overall level in terms of coherency with the γ matrix, but also at very local level regarding local lattice variations between γ′ precipitate populations. Morphological, compositional and structural variations between different γ′ precipitate populations were detected and explained using thermodynamic principles. Operando observations revealed differences in terms of evolution (growth, dissolution) between different γ′ precipitate populations, shedding light on the underlying physical phenomena that accompany their formation. This Thesis provides useful guidelines to optimise the processing conditions to tailor the distribution of γ′ precipitate populations to obtain the desired mechanical performance. The research presented in this Thesis provides valuable findings developed for high γ′ content nickel base superalloys but with broad applicability to various precipitation-hardened alloy systems.
Modular origami-inspired kinematic metamaterials
Keywords: shape morphing
linkage mechanisms
reconfigurable metamaterial
modular origami
mechanical metamaterial
kinematics

This dissertation proposed a kinematic-based construction method for reconfigurable mechanical metamaterials. This was achieved by entrenching kinematic mechanisms with predefined motion paths within the unit cells of the metamaterial and connecting the units according to carefully chosen topology pattern. The developed metamaterials are able to perform complex transformation between different configurations, which brings superior tuneable physical properties. The major findings of this dissertation are in following four areas.
First, this research built a bridge between mechanism networks and mechanical metamaterials. The theories of planar and spatial mechanisms were utilised to analyse and program the behaviour of metamaterials. Various interesting metamaterials were developed, including materials whose expansion ratio, volumetric strain and porosity are programmable; structures with multiple deformation paths due to their built-in kinematic bifurcation; and metamaterials with constant negative Poisson’s ratios that can be programmed by the parameters of the building blocks. The kinematic-induced design strategy paves the way for a new class of metamaterials that can perform reliable large deformation along predefined motion paths.
Second, different strategies to construct three dimensional (3D) kinematic metamaterials were investigated. While most current origami metamaterials focus on thin shell planar structures, this thesis endeavoured to explore 3D materials. A tilting unit method was proposed for single layer 3D metamaterial, whereas a spatial mechanism-entrenched design strategy was developed for more general 3D metamaterials. The topology and transformation of the unit cells were obtained using the kinematic analysis so that the tuneability of the material became a built-in feature of these metamaterials.
Third, an application of kinematic metamaterials as frequency selective surfaces has been investigated. The metamaterials were designed to have multi-stable states so that it can be locked mechanically in various configurations corresponding to specific passband. The metamaterials were fabricated and tested in electromagnetics experiments to validate their functionality.
Finally, the fabrication strategies of various kinematic metamaterials were explored. Laser engraving technique was mainly used for planar metamaterials. For 3D metamaterials, a multi-material 3D printing method was investigated for millimetre-scale samples, and a multi-process lamination method was developed for meso-scale paper prototypes. These methods provided rich and useful experience for the development of functional metamaterials in the future.
Investigating the extent to which informal mentoring by recently retired teachers of Physics can support beginner teachers of Physics to grow in their teacher knowledge and influence their retention in teaching
Keywords: MTED 2020
MTED

The experiences of beginner teachers of physics in their first year of teaching and the factors affecting their intentions to remain in the profession are explored and contrasted with what is known from the literature. Findings from this include feelings of isolation, lack of subject specific support and low time availability of supportive colleagues in schools. These, and what is known about teacher professional learning, are used to inform a small-scale qualitative study of using recently retired physics teachers to informally mentor new teachers of physics over a period of one year. Case studies of the mentor and mentees are presented using data from the contents of mentoring conversations and these are analysed to explore the extent to which this type of informal mentoring can support professional knowledge growth in new physics teachers and influence their decisions to remain in the profession. Findings show that the main areas of professional knowledge addressed by the mentoring are behaviour management and pedagogical content knowledge (PCK). A key factor in the success of the mentoring was its informality and relationship to other forms of support and mentoring available to the new physics teacher. Implications for teacher educators about the benefits and limitations of this type of mentoring are considered and proposals for further study made.
Towards large scale quantum networks
Keywords: remote entanglement
temporal mixing
quantum computer
trapped ion
cavity enhancement
atomic ensemble
single photon source

Quantum computing has the potential to solve problems that take current classical computers much longer to solve. The last two decades witnessed a substantial development of various physical platforms, most of which have shown a "Proof of principle" demonstration for quantum computing. We are now in a critical stage where the goal is to develop the system to a large scale so that we can make quantum computing useful for real world applications. However, the question of which physical platform shows most promise remains uncertain. In this thesis, I examine two mainstream platforms: linear optics and trapped ions, from the point of view of scalability. For each platform, my own work has focused particularly on how to model and engineer the temporal properties of single photons.
For linear optical quantum computing, I propose to use an off-resonant cascaded absorption (ORCA) buffer to purify and unify the single-photons from different noisy sources. A proof of principle experiment is demonstrated to show that the ORCA buffer is in principle, noise-free. Simulation suggests that with the current ORCA buffer, we can purify the single-photon source better than with ideal intensity filtering. Meanwhile, it can unify different sources and increase the inter-indistinguishability from 60% to 96%.
For the trapped ion system, one promising scalable approach is to use photons to mediate entanglement between ions in remote traps. To achieve this, ion-photon entanglement must first be generated. We propose to use a cavity-enhanced Raman transition on the D3/2 → P3/2 → D5/2 λ-system' in a strontium ion level scheme for ion-photon entanglement generation. A full mathematical description is constructed to describe the entanglement dynamics considering the Rayleigh-scattering-induced temporal mixing noise. With this theory, simulation shows that we expect to achieve ion-ion remote entanglement rate of more than 75KHz with negligible infidelity from temporal mixing noise. Both proposals, if fully demonstrated experimentally, will be powerful tools to solve the scalability challenge for their respective systems, paving the way towards large scale realistic quantum computing.
Education, aspiration, and mobility in the Karen borderlands: An ethnography of youth transitions amongst the Kwaegabon Plong Karen of southeastern Burma/Myanmar
Keywords: Temporal Mobilities
Democratic Transition
Migration
Aspiration &amp; Agency
(International) Development
Karen Peoples
Social Navigation
Southeast Asia
Youth Mobility
Burma/Myanmar
Ethnography
(Non-State) Education
Socio-Spatial Mobilities

Existing research on education-to-employment transitions in complex and contested settings in the global South is consumed with the debilitating effects of the ‘crisis of youth’ and its negative outcomes in which many emerge un/under-employed. Young people are often depicted as in thrall to this predicament rather than probing their agentive capacities for affirmative action to move beyond the impasse. Consequently, few studies explore how youth transitions relate and respond to wider socio-economic and political transformation as young people set about changing the self and the situation.
Based on fieldwork conducted throughout 2015 and 2016 in a remote region of southeastern Burma/Myanmar emerging from decades of armed conflict, government restriction and underdevelopment, this thesis explores how a community of Plong Karen in the Karen State capital Hpa-an, engaging around alternative forms of higher education, are responding directly to local configurations of privation and possibility. By shaping the aspirations and agency of high school and university students to safeguard the legacy of this, this provision amounts to a formidable vision and vehicle of social change.
Adopting an interdisciplinary approach, I bring a concern for temporalities into conversation with socio-spatial mobilities to explore ways in which young people navigate their structured positions and exploit the possibilities around them before and into Myanmar’s political transition, and across the Karen borderlands into neighbouring Thailand. I explore how specific struggles and successes around education, shared by this particular social ‘generation’ across these time-spaces, have informed their capacity to act and the manner in which they are doing so. I suggest that these outcomes are stimulating broader socio-economic transformations within and beyond this community. Access to this education and the opportunities it promises, nevertheless presents young people with new and beguiling possibilities beyond the constraints and concerns of those communities, which remain marked by the spectre of intra-ethnic and religious tensions testing the identifications and affiliations of young people living and learning in contemporary Hpa-an.