Cognitive, social and emotional processes in unawareness of illness following stroke

Includes bibliographical referencesDisturbances in unawareness can offer an important avenue to investigate the neurocognitive processes involved in the construction of the bodily self. The general aim of the present thesis was to advance the current state of knowledge on a prototypical disorder of self-awareness, anosognosia for hemiplegia (AHP): unawareness of motor deficits contralateral to a brain lesion. Based on insights gained from both clinical and experimental research on anosognosia, it is argued that purely sensorimotor accounts do not explain several features of the syndrome, such as the delusional and emotional aspects. Therefore a revision of prevailing, modular theories of anosognosia is proposed that take into account the involvement of affective and so cial processes. Accordingly, the thesis aimed to: (1) investig ate the emotional and social factors that underlie motor unawareness; (2) identify the neurocognitive factors and neuroanatomical correlate that underlie such factors; and (3) develop potential, bedside rehabilitation interventions for AHP that are informed by the above investigations. These aims were achieved using an integrative methodological approach, which combined neuropsychological testing, psychophysiological experiments and neuroimaging methods. A series of experiment al group investigations and clinical case studies were conducted in 53 adult patients with right-hemisphere strokes. The main results of these studies showed that: (i) motor awareness is modulated by negative, but not positive emotion in a social context; (ii) anosognosia is associated with specific deficits in 3rd person perspective taking in visual-spatial and mentalising tasks; (iii) anosognosia is modulated by 'other' referent and 3rd person verbal and visual perspective taking. These experimental findings on the role of emotion and social processes in AHP were in turn used to develop a rehabilitation intervention applied in two case studies that showed promising results. Additionally, converging neuroimaging evidence provided support for the unique involvement of the inferior frontal gyrus, insula ribbon, supramarginal and superior temporal gyrus, and dorsal frontal white matter in anosognosia, which have well-established links to motor monitoring, subjecting feelings and self-awareness, and the proposed 'mentalising network'. These finding are in support of a proposed new account of AHP, which move s away from traditional modular theories of anosognosia, towards a dynamic model of the construction of the bodily self

Design of a high speed high power switched reluctance motor

PhD ThesisAn increase in the price of rare earth materials in 2009 prompted research into alternative motor technologies without permanent magnets. The SRMs have become more of an attractive solution as they are relatively simpler to construct than other machines technologies hence cost effective. Furthermore, the rugged structure of the rotor makes it suitable for high speed operation, if appropriately designed. This thesis investigates the design, analysis and prototype manufacture of an SRM, that from electromagnetic point of view, meets the power output of the PM machine used in the Toyota Prius, although operating at a higher speed of 50,000 rpm. As a result, the required torque is considerably less than an equivalent motor with the same output power running at lower speed, hence this approach allows for much smaller frame sizes. To achieve the required torque, careful choice of stator/rotor tooth combination, coil number of turns and number of phases is needed. Running at high speed, increases the AC copper loss (consisting of skin effect and proximity effects) and iron loss. These shortcomings are extensively discussed and investigated. The mechanical design of this motor requires careful consideration in order to minimise the high mechanical stresses acting upon the rotor, which are due to the high radial forces caused by the centripetal force at high speed. In order to address the mechanical constraints caused by the hoop stress, a structure common to flywheels is applied to the rotor. In this approach, the shaft bore is removed and the laminations are sandwiched together using cheek plates, which are secured using tie rods. The cheek plates have their extending shafts, which consequently will transfer the torque to the rest of the system. The proposed model is analysed for both the electromagnetic and mechanical aspects, successfully demonstrating a promising rotor topology for the design speed. A high speed motor design needs to take into account shaft design, rotor design and bearing design. The high speed operation of the salient rotor gives dramatic rise to the windage loss. These factors are carefully considered in this work and the results are presented

Understanding how and why spatial segregation endures: A systematic review of recent research on intergroup relations at a micro-ecological scale

Social psychological research has increasingly extolled the benefits of intergroup contact as a means of promoting positive relations. However, a growing body of research suggests that formal policies of desegregation are often offset by informal ‘micro-ecological’ practices of (re)-segregation, in everyday life spaces. This paper presents a systematic literature review of recent evidence on this topic (2001-2017), outlining key findings about how, when, where, and why micro-ecological divisions are reproduced. Informal segregation can happen based on ethnicity, religion, socioeconomic status, gender, or gender and ethnicity, despite people being in a shared place. People generally maintain patterns of ingroup isolation as a result of: a) negative attitudes and stereotypes; b) ingroup identification and threat; or c) feelings of anxiety, fear and insecurity. Educational settings have been the main context studied, followed by leisure and recreational places, public urban places and public transport. The paper also identifies three areas of potential future research, highlighting the need to: (1) capitalise on methodological innovations; (2) explore systematically how, when and why the intersectionality of social categories may shape micro-ecological practices of contact and separation; and (3) understand more fully why micro-ecological patterns of segregation are apparently so persistent, as well as how they might be reduced