Limit groups, positive-genus towers and measure equivalence

By definition, an $\omega$-residually free tower is positive-genus if all surfaces used in its construction are of positive genus. We prove that every limit group is virtually a subgroup of a positive-genus $\omega$-residually free tower. By combining this with results of Gaboriau, we prove that elementarily free groups are measure equivalent to free groups.Comment: 10 pages; no figures. Minor changes; now to appear in Ergod. Th. & Dynam. Sy

ECOLOGIES OF SPONSORSHIP: WHAT FITBIT USERS CAN TEACH US ABOUT DIGITAL LITERACY

As digital technologies have expanded, so have the literacy sponsors that support and shape how those technologies are used. This project focuses on one of these growing sites of sponsorship surrounding a specific health-tracking technology: wearable Fitbit devices. While much of the work on literacy sponsorship has focused on institutional sponsors as agents, I argue that the picture becomes more complicated and interesting when we place our focus on how users—often considered the sponsored—can become agents in a system that may have marginalized, excluded, or used them. Using a combination of qualitative methods, this dissertation highlights how various literacy sponsors create possibilities and constraints, how communities of users support and resist these frameworks, and how users can become digital literacy sponsors. This research maps the ecologies of sponsorship that Fitbit users engage in as both consumers and producers. The concept of “ecologies of sponsorship” is a unique contribution of this project, which expands traditional frameworks for understanding the stakeholders in literacy development to account for digital, networked environments. In addition to typical tracking practices, this research found that significant groups of users “hack” the technology to help them work toward subversive goals. Some users reject the stated purposes of health-tracking technology, instead manipulating their data to create an illusion of health. Some of these users have shared their alternative goals and tactics in online communities, which allows them to become sponsors of metistic digital literacies. Rather than transforming Fitbit technology and ideologies of health through explicit hostility or force, this research explores how users developed metistic practices to subvert health-tracking systems from within. Though this research focuses on the development of digital literacies in extra-curricular spaces, there are important implications for writing classrooms that aim to help students develop digital literacies. This research raises questions about how our classroom practices might shift if we add metistic literacies to frameworks that already support functional, critical, and rhetorical literacies. And by considering classroom-based teaching in the context of larger ecologies of sponsorship, this research highlights a need for new pedagogical practices that account for the distributed nature of technological expertise

A self-compassion intervention for healthy adolescents: Can it enhance self-compassion and reduce social comparison?

This thesis is concerned with adolescent mental health and wellbeing. It is presented in three parts. Part One: Literature Review. A systematic review of 20 studies, both cross-sectional and longitudinal, that investigated the relationship between school-related stress and depressive symptoms in adolescents. Significant positive relationships were found between school-related stress and depressive symptoms; however, the causal direction of this relationship is questionable as most studies were cross-sectional. Additionally, a number of studies found effects of moderating and mediating factors, such as gender. Further high-quality, longitudinal studies need to be conducted to assess the strength and direction of this relationship. Part Two: Empirical Paper. This consisted of an exploratory randomised control study to investigate the effectiveness of a three session self-compassion psychoeducation group with an imagery task, compared to a psychoeducation group alone or control group. It was conducted as a joint project with another UCL Clinical Psychology Doctorate student (Tweed, 2019). Improvements in self-compassion and social comparison were found in the psychoeducation group, but not the psychoeducation and imagery group. Within the imagery group there was evidence that the greater the ability of the participants to vividly imagine the imagery task, the greater the improvements they experienced. Acceptability feedback of the intervention sessions was positive, although there were questions regarding the acceptability of inter-session tasks. Part Three: Critical Appraisal. A reflection and appraisal focused on the empirical paper. This includes methodological and practical issues encountered during the study alongside consideration of wider issues relating to school-based research

Using Multi-agent Systems to Pursue Autonomy with Automated Components

AbstractHumans have used tools to transform raw resources into valued outputs ever since society harnessed fire. The type of tool, amount of effort and form of energy required depends on the output or object being created. As tools evolved into machines, they enhanced operator productivity. Hence, industry continues to invest heavily in machines to assist people to do more with less physical control and/or interaction. This involves automating functions previously completed manually. Taylorism and the Hawthorn experiments all contributed to optimising industrial outputs and value engineers continue to promote a mecha- nized workforce in order to minimise business variations in human performance and their behaviour. Researchers have also pursued this goal using Computational Intelligence (CI) techniques. This process of transforming cognitive functionality into machine actionable form has encompassed many careers. Machine Intelligence (MI) is becoming more aspirational, with Artificial Intelligence (AI) enabling the achievement of numerous goals. More recently, Multi-Agent Systems (MASs) have been employed to provide a flexible framework for research and development. These frameworks facilitate the development of component interoperability, with coordination and cooperation techniques needed to solve real-world problems. However problems typically manifest in complex, dynamic and often hostile environments. Based on the effort to seek or facilitate human-like decision making within machines, it is clear that further research is required. This paper discusses one possible avenue. It involves future research, aimed at achieving a cognitive sub-system for use on-board platforms. The framework is introduced by describing the human-machine relationship, followed by the theoretic background into cognitive architectures and a conceptual mechanism that could be used to implement a virtual mind. One which could be used to improve automation, achieve greater independence and enable more autonomous behaviour within control systems

Deficiency and abelianized deficiency of some virtually free groups

Let $Q_m$ be the HNN extension of $\Z/m \times \Z/m$ where the stable letter conjugates the first factor to the second. We explore small presentations of the groups $\Gamma_{m,n}=Q_m \ast Q_n$. We show that for certain choices of (m,n), for example (2,3), the group $\Gamma_{m,n}$ has a relation gap unless it admits a presentation with at most 3 defining relations, and we establish restrictions on the possible form of such a presentation. We then associate to each (m,n) a 3-complex with 16 cells. This 3-complex is a counterexample to the D(2) conjecture if $\Gamma_{m,n}$ has a relation gap.Comment: 7 pages; no figures. Minor changes; now to appear in Math. Proc. Camb. Phil. So

An investigation into the synthesis and properties of some fluorinated polycarbonates

This thesis describes the synthesis and characterisation of several fluorinated aliphatic, aliphatic and aliphatic ether polycarbonates. The thesis is divided into four sections. In the first section the origins and motivation for the work are discussed, essentially the work forms part of a long term project concerned with the development of a predictively useful correlation between the structure of a polymer repeat unit and its glass transition temperature (Tg). In the second section the various methods for aliphatic polycarbonate synthesis are critically discussed together with the reason for selecting the method used in this work. The third section describes the progressive development of the eventually successful synthetic method and its application to the preparation of ten polycarbonates. The final section is concerned with the detailed characterisation of the polymers obtained, in particular with establishing that they were high polymers of the correct structure, and the measurement of their glass transition temperatures and thermal stabilities. The results of this work suggest that the theoretical oasis for the prediction of the glass transition temperatures of polymers is not presently particularly reliable. Part of the difficulty in developing a more predictively useful theory arises from the uncertainties associated with published values for Tg and a useful contribution of this work is to provide a further ten reliable data points for well characterised materials

The British press and Northern Ireland : a case study in the reporting of violent political conflict.

The study presented here focuses on the treatment accorded to Northern Ireland by the British press since 1969. It argues that the press has failed to provide the public with an impartial or meaningful account of the conflict in the North, and explores some of the factors that have contributed to this failure. Chapter One outlines the primary functions that have been ascribed to journalists and the press in democratic society, and provides a standard against which press performance may be judged. Chapter Two evaluates a range of commentaries on the British media's reporting of Northern Ireland from Partition to the present day. The study moves on to examine the debate over the media's representation of "terrorism" and assesses the consequences of this debate for the British media's reporting of Northern Ireland. Chapter Four provides an account of the research methods employed in the study and reflects on some of the practical problems encountered during the course of the fieldwork. Chapter Five presents the findings of a content analysis of the coverage accorded to civilian assassinations by seven British and two Northern Irish newspapers during a five week period in 1972. Chapter Six outlines the development of the information services operated by the army and the police, and describes how these forces have used their strategic position as a news source to gain the edge in the propaganda war. Picking up on some of the themes and issues raised in previous chapters, Chapter Seven focuses on those involved in the production of news and presents the findings of a series of interviews undertaken with journalists in Belfast and London. The final chapter summarises the principal findings of the study and reflects on the prospects of a reversal in the present approach to the reporting of Northern Ireland by the British press