Causality and synchronisation in complex systems with applications to neuroscience

This thesis presents an investigation, of synchronisation and causality, motivated by problems in computational neuroscience. The thesis addresses both theoretical and practical signal processing issues regarding the estimation of interdependence from a set of multivariate data generated by a complex underlying dynamical system. This topic is driven by a series of problems in neuroscience, which represents the principal background motive behind the material in this work. The underlying system is the human brain and the generative process of the data is based on modern electromagnetic neuroimaging methods . In this thesis, the underlying functional of the brain mechanisms are derived from the recent mathematical formalism of dynamical systems in complex networks. This is justified principally on the grounds of the complex hierarchical and multiscale nature of the brain and it offers new methods of analysis to model its emergent phenomena. A fundamental approach to study the neural activity is to investigate the connectivity pattern developed by the brain’s complex network. Three types of connectivity are important to study: 1) anatomical connectivity refering to the physical links forming the topology of the brain network; 2) effective connectivity concerning with the way the neural elements communicate with each other using the brain’s anatomical structure, through phenomena of synchronisation and information transfer; 3) functional connectivity, presenting an epistemic concept which alludes to the interdependence between data measured from the brain network. The main contribution of this thesis is to present, apply and discuss novel algorithms of functional connectivities, which are designed to extract different specific aspects of interaction between the underlying generators of the data. Firstly, a univariate statistic is developed to allow for indirect assessment of synchronisation in the local network from a single time series. This approach is useful in inferring the coupling as in a local cortical area as observed by a single measurement electrode. Secondly, different existing methods of phase synchronisation are considered from the perspective of experimental data analysis and inference of coupling from observed data. These methods are designed to address the estimation of medium to long range connectivity and their differences are particularly relevant in the context of volume conduction, that is known to produce spurious detections of connectivity. Finally, an asymmetric temporal metric is introduced in order to detect the direction of the coupling between different regions of the brain. The method developed in this thesis is based on a machine learning extensions of the well known concept of Granger causality. The thesis discussion is developed alongside examples of synthetic and experimental real data. The synthetic data are simulations of complex dynamical systems with the intention to mimic the behaviour of simple cortical neural assemblies. They are helpful to test the techniques developed in this thesis. The real datasets are provided to illustrate the problem of brain connectivity in the case of important neurological disorders such as Epilepsy and Parkinson’s disease. The methods of functional connectivity in this thesis are applied to intracranial EEG recordings in order to extract features, which characterize underlying spatiotemporal dynamics before during and after an epileptic seizure and predict seizure location and onset prior to conventional electrographic signs. The methodology is also applied to a MEG dataset containing healthy, Parkinson’s and dementia subjects with the scope of distinguishing patterns of pathological from physiological connectivity.

Kant and Darwin

The central theses of Kant's critical philosophy are sometimes said to have been overtaken by evolutionary biology. This paper considers how far this proposition can be sustained. I argue that the ‘architectonic’ or ‘system-building’ character of the mind, the categories and the forms of intuition, can indeed be seen as the outcome of a particular evolutionary lineage in a Darwinian world. I argue, further, that the principal motive energizing the critical philosophy is the 'nightmare' of physical determinism. An alternative escape route from this particular nightmare is rehearsed. If this route is taken, the intricate arguments of the Critiques are unnecessary to save moral action in a world of things. Nonetheless, insofar as 'first philosophy' necessarily starts from within the philosopher's own subjectivity, Kant's work retains its power. I suggest that the Kantian and the Darwinian interpretations are to an extent complementary. If this is so, some form of evolutionarily-informed dual-aspect psychoneural identity theory could combine the essence of the two interpretations.

Rough-terrain groundspeed measurement:a radar-based commercial solution

Off-highway motive plant equipment is costly in capital outlay and maintenance. To reduce these overheads and increase site safety and workrate, a technique of assessing and limiting the velocity of such equipment is required. Due to the extreme environmental conditions met on such sites, conventional velocity measurement techniques are inappropriate. Ogden Electronics Limited were formed specifically to manufacture a motive plant safety system incorporating a speed sensor and sanction unit; to date, the only such commercial unit available. However, problems plague the reliability, accuracy and mass production of this unit. This project assesses the company's exisiting product, and in conjunction with an appreciation of the company history and structure, concludes that this unit is unsuited to its intended application. Means of improving the measurement accuracy and longevity of this unit, commensurate with the company's limited resources and experience, are proposed, both for immediate retrofit and for longer term use. This information is presented in the form of a number of internal reports for the company. The off-highway environment is examined; and in conjunction with an evaluation of means of obtaining a returned signal, comparisons of processing techniques, and on-site gathering of previously unavailable data, preliminary designs for an alternative product are drafted. Theoretical aspects are covered by a literature review of ground-pointing radar, vehicular radar, and velocity measuring systems. This review establishes and collates the body of knowledge in areas previously considered unrelated. Based upon this work, a new design is proposed which is suitable for incorporation into the existing company product range. Following production engineering of the design, five units were constructed, tested and evaluated on-site. After extended field trials, this design has shown itself to possess greater accuracy, reliability and versatility than the existing sensor, at a lower unit cost.

The gendered academy:women academics as agents for change

This paper explores the experiences of women academics who have undertaken research on gender in their own organisations. In particular those who have undertaken research with the motive to upset the systematic gender order. Our preliminary analysis of five interviews with female academics, at a range of stages in their careers, has highlighted three key concerns: first that gender research is still largely seen as women’s work within the academy, second that the relation between female academic’s gender research and their identity as academics and as professionals remains an uncomfortable one and third that their objective of effecting change to the gender order in their institutions remains elusive.

Textbook (non-)adoption motives, legitimizing strategies and academic field configuration

Textbooks are an integral part of structured syllabus coverage in higher education. The argument advanced in this article is that textbooks are not simply products of inscription and embodied scholarly labour for pedagogical purposes, but embedded institutional artefacts that configure entire academic subject fields. Empirically, this article shows the various ways that motives of the (non-) adoption of textbooks have field institutional configuration effects. The research contribution of our study is threefold. First, we re-theorise the textbook as an artefact that is part of the institutional work and epistemic culture of academia. Second, we empirically show that the vocabularies of motive of textbook (non-) adoption and rhetorical strategies form the basis for social action and configuration across micro, meso and macro field levels. Our final contribution is a conceptualization of the ways that textbook (non-) adoption motives ascribe meaning to the legitimating processes in the configuration of whole subject fields.

Die unvermeidlichen Sonette: Thomas Mann und Shakespeare

Thomas Mann empfand zeitlebens eine große Bewunderung für Shakespeare, die sich in der für seine literarische Arbeitsweise typischen Form der intertextuellen Bezugnahme auf die Werke des englischen Klassikers offenbart. Diese literarische Beziehung lässt sich anhand deutlicher Allusionen von den Anfängen bis ins Spätwerk verfolgen und kulminiert im Doktor Faustus. Innerhalb der Shakespeare-Anspielungen in diesem Roman nehmen Bezüge zu den Sonetten eine zentrale Rolle ein. Über Jahrzehnte hinweg zeigte sich Thomas Mann fasziniert von diesen Gedichten und setzte sich vielfach mit der in ihnen dargestellten Verbindung von hetero- und homosexueller Anziehung sowie der zentralen Thematik künstlerischer Verewigung auseinander. Diese beiden Themenkreise stehen auch hier im Vordergrund und bilden eine Folie für Aspekte der Beziehung zwischen Leverkühn und Rudi Schwerdtfeger, wobei Thomas Mann nicht nur Motive aus den Gedichten aufgriff, sondern ebenfalls auf die Entstehungssituation der Sonette und ihre vermutete autobiographische Dimension Bezug nahm: Leverkühn - seinerseits ein Selbstporträt seines Autors - nimmt so zugleich die Rolle einer Shakespeareschen Figur und die Position des englischen Dichters selbst ein. Darüber hinaus ist sich Thomas Manns Protagonist dieser literarischen Beziehungen in hohem Grade bewusst und gestaltet sie selbst entscheidend mit. Wie keine andere Mannsche Gestalt vor ihm greift Leverkühn als Hauptfigur in die Handlung ein, manipuliert und inszeniert das Romangeschehen anhand literarischer Vorlagen. Dadurch erhält Thomas Manns komplexe Verwendung von Intertextualität eine zusätzliche Dimension und nimmt in diesem späten Roman geradezu postmoderne Züge an.

Geschlechtsspezifische Unterschiede in der Bewertung von Unternehmenserfolg

Ziel vorliegender Studie waren eine explorative Analyse der Definition des unternehmerischen Erfolgs sowie eine Überprüfung, inwieweit sich die Geschlechter in der Definition von Unternehmenserfolg unterscheiden. Weiterhin wurden die Motive für die Selbstständigkeit bei Frauen untersucht. Die Ergebnisse zeigen, dass sowohl Unternehmer als auch Unternehmerinnen unternehmerischen Erfolg relativ breit definieren. Für beide Gruppen beinhaltet er sowohl finanzielle (Unternehmensleistung und persönliche Belohnung) als auch nicht finanzielle Aspekte (Arbeitsbeziehungen, Selbstverwirklichung und sozialer Erfolg). Weiterhin wurde bestätigt, dass Frauen den unternehmerischen Erfolg überwiegend über die sogenannten sozioemotionalen Kriterien definieren, während Männer die traditionellen statusbezogenen Aspekte und Leistung hervorheben. Die Analyse der Motive für Selbstständigkeit ergab, dass Unternehmerinnen besonders nach Selbstverwirklichung und Unabhängigkeit streben und in ihrem Durchsetzungsvermögen sowie in Kooperation und Rücksichtnahme ihre Stärken sehen. Fehlende Balance zwischen Familie und Beruf erleben sie als (unternehmerinnenspezifische) Schwierigkeit.

The antecedents and consequences of anticipatory identification

The aim of this thesis was to investigate anticipatory identification: newcomers’ identification with an organisation prior to entry; in particular by exploring the antecedents and consequences of the construct. Although organisational identification has been frequently investigated over the past 25 years, surprisingly little is known about what causes an individual to identify with a new organisation before entry and whether this has an impact on their relationship with the organisation after formally taking up membership. Drawing on a Social Identity approach to organisational identification, it was hypothesised that newcomers would more closely identify with an organisation prior to entry when the organisation was seen as a source of positive social identity and was situationally relevant and meaningful to the newcomer, i.e. salient, during the pre-entry period. It was also hypothesised that anticipatory identification would have post-entry consequences and would predict newcomers’ post-entry identification, turnover intentions and job satisfaction. An indirect relationship between anticipatory identification and post-entry identification through post-entry social identity judgements (termed a “feedback loop” mechanism) was additionally proposed. Finally anticipatory identification was also predicted to moderate the relationship between post-entry social identity judgements and post-entry identification (termed a “buffering” mechanism). Four studies were conducted to test these hypotheses. Study One served as a pilot study, using a retrospective self-report design with s sample of 124 university students to initially test the proposed conceptual model. Studies Two and Three adopted experimental designs. Each used a unique sample of 72 staff and students from Aston University to respectively test the hypothesised positive social identity motive and salience antecedents of anticipatory identification. Study Four explored the relationship between anticipatory identification, its antecedents and consequences longitudinally, using an organisational sample of 45 employees. Overall, these studies found support for a social identity motive antecedent of anticipatory identification, as well as more limited evidence that anticipatory identification was associated with the salience of an organisation prior to entry. Support was inconsistent for a direct relationship between anticipatory identification and post-entry identification and there was no evidence that anticipatory identification was a significant direct predictor of turnover intention and job satisfaction. Anticipatory identification was however found to act as a buffer in the relationship between post-entry social identity judgements and post-entry identification in all but one of the four samples measured. A feedback loop mechanism was observed within the experimental designs of Studies Two and Three, but not within the organisational samples of Studies One and Four. Overall the findings of these four studies highlight key ways through which anticipatory identification can develop prior to entry into an organisation. Moreover, the research observed several important post-entry consequences of anticipatory identification, indicating that an understanding of post-entry identification may be enriched by attending more closely to the extent to which newcomers identify with an organisation prior to entry.

An exploration of pharmacy-specific reasons for non-adherence to prescribed medicines in a socioeconomically deprived, ethnically diverse UK cohort

Methods - Ethical approval for the study was granted by both the local National Health Service (NHS) Research Ethics Committee (REC) and Aston University’s REC. Seven focus groups were conducted between October and December 2011 in medical or community settings within inner-city Birmingham (UK). Discussions were guided by a theme plan which was developed from key themes identified by a literature review and piloted via a Patient Consultation Group. Each focus group had between 3 and 7 participants. The groups were digitally recorded and subsequently transcribed verbatim. The transcriptions were then subjected to thematic analysis via constant comparison in order to identify emerging themes. Results - Participants recognised the pharmacist as an expert source of advice about prescribed medicines, a source they frequently felt a need to consult as a result of the inadequate supply of medicines information from the prescriber. However, an emerging theme was a perception that pharmacists had an oblique profit motive relating to the supply of generic medicines with frequent changes to the ‘brand’ of generic supplied being attributed to profit-seeking by pharmacists. Such changes had a negative impact on the patient’s perceived efficacy of the therapy which may make non-adherence more likely. Conclusions - Whilst pharmacists were recognised as medicines experts, trust in the pharmacist was undermined by frequent changes to generic medicines. Such changes have the potential to adversely impact adherence levels. Further, quantitative research is recommended to examine if such views are generalisable to the wider population of Birmingham and to establish if such views impact on adherence levels.