Comparative study of symmetric and asymmetric cylindrical MRI gradient Y-coils in terms of induced eddy currents

We have recently introduced the concept of whole-body asymmetric MRI systems [1]. In this theoretical study, we investigate the PNS characteristics of whole-body asymmetric gradient systems as compared to conventional symmetric systems. Recent experimental evidence [2] supports the hypothesis of transverse gradients being the largest contributor of PNS due to induced electric currents. Asymmetric head gradient coils have demonstrated benefits in the past [3]. The numerical results are based on an anatomically-accurate 2mm-human voxel-phantom NORMAN [4]. The results of this study can facilitate the optimization of whole-body asymmetric gradients in terms of patient comfort/safety (less PNS), while prospering the use of asymmetric MRI systems for in-vivo medical interventions.

Cohesion in text differentiation : a study of English and Arabic

This thesis sets out to investigate the role of cohesion in the organisation and processing of three text types in English and Arabic. In other words, it attempts to shed some light on the descriptive and explanatory power of cohesion in different text typologies. To this effect, three text types, namely, literary fictional narrative, newspaper editorial and science were analysed to ascertain the intra- and inter-sentential trends in textual cohesion characteristic of each text type in each language. In addition, two small scale experiments which aimed at exploring the facilitatory effect of one cohesive device (i.e. lexical repetition) on the comprehension of three English text types by Arab learners were carried out. The first experiment examined this effect in an English science text; the second covered three English text types, i.e. fictional narrative, culturally-oriented and science. Some interesting and significant results have emerged from the textual analysis and the pilot studies. Most importantly, each text type tends to utilize the cohesive trends that are compatible with its readership, reader knowledge, reading style and pedagogical purpose. Whereas fictional narratives largely cohere through pronominal co-reference, editorials and science texts derive much cohesion from lexical repetition. As for cross-language differences English opts for economy in the use of cohesive devices, while Arabic largely coheres through the redundant effect created by the high frequency of most of those devices. Thus, cohesion is proved to be a variable rather than a homogeneous phenomenon which is dictated by text type among other factors. The results of the experiments suggest that lexical repetition does facilitate the comprehension of English texts by Arab learners. Fictional narratives are found to be easier to process and understand than expository texts. Consequently, cohesion can assist in the processing of text as it can in its creation.

A linguistic study of interview and conversation

The present thesis focuses on the overall structure of the language of two types of Speech Exchange Systems (SES) : Interview (INT) and Conversation (CON). The linguistic structure of INT and CON are quantitatively investigated on three different but interrelated levels of analysis : Lexis, Syntax and Information Structure. The corpus of data 1n vest1gated for the project consists of eight sessions of pairs of conversants in carefully planned interviews followed by unplanned, surreptitiously recorded conversational encounters of the same pairs of speakers. The data comprise a total of approximately 15.200 words of INT talk and of about 19.200 words in CON. Taking account of the debatable assumption that the language of SES might be complex on certain linguistic levels (e.g. syntax) (Halliday 1979) and might be simple on others (e.g. lexis) in comparison to written discourse, the thesis sets out to investigate this complexity using a statistical approach to the computation of the structures recurrent in the language of INT and CON. The findings indicate clearly the presence of linguistic complexity in both types. They also show the language of INT to be slightly more syntactically and lexically complex than that of CON. Lexical density seems to be relatively high in both types of spoken discourse. The language of INT seems to be more complex than that of CON on the level of information structure too. This is manifested in the greater use of Inferable and other linguistically complex entities of discourse. Halliday's suggestion that the language of SES is syntactically complex is confirmed but not the one that the more casual the conversation is the more syntactically complex it becomes. The results of the analysis point to the general conclusion that the linguistic complexity of types of SES is not only in the high recurrence of syntactic structures, but also in the combination of these features with each other and with other linguistic and extralinguistic features. The linguistic analysis of the language of SES can be useful in understanding and pinpointing the intricacies of spoken discourse in general and will help discourse analysts and applied linguists in exploiting it both for theoretical and pedagogical purposes.

Expatriate managers adjustment and its impact on subordinates reactions: a cross cultural leadership study of Kenya and Ethiopia

Research on culture, leadership and adjustment shows that societal culture influences leadership in such a way that it can impact on expatriate managers' effectiveness and adjustment in a new culture. In previous research, cultural background, personality, motives or behaviour of expatriate managers and their followers' reactions to them have been investigated in Europe, America and Asia. However, little attention has been paid on research on expatriate managers in African cultures especially in Eastern Africa. The present study represents an attempt to address the gap by examining how societal culture, leadership and adjustment success are interrelated for expatriate managers in Kenya and Ethiopia. Questionnaire data were obtained from a) local middle managers (N=160) for studying societal culture and leadership in Kenya and Ethiopia, b) expatriate managers in non-governmental organizations - NGOs (N=28) for studying expatriate managers' personality, motives and adjustment success and c) their immediate subordinates (N=125) for studying the expatriate managers' behaviours and their subordinates' reactions to them. Additionally, expatriate managers were interviewed and responses were coded for implicit motives, experiences and adjustment. SPSS was used to analyse data from questionnaires to obtain cultural and leadership dimensions, leader behaviour and subordinate reactions. The NVIVO computer based disclosure analysis package was used to analyse interview data. Findings indicate that societal culture influences leadership behaviours and leadership perceptions while the expatriate managers' motives, behaviours, personality and the cross cultural training they received prior to their assignment impact on the expatriates' adjustment success and on subordinates' reactions to them. The cultural fit between expatriate managers' home country (19 countries) and the target country (Kenya or Ethiopia) had no significant association with adjustment success but was positively related to expatriate behaviour and negatively associated with subordinates reactions. However, some particular societal practices - obviously adopted by expatriates and transferred to their target country - did predict subordinates' commitment, motivation and job satisfaction. Furthermore, expatriates' responsibility motivation was positively related to their adjustment success. Regarding leadership behaviours and effectiveness, expatriate' supportive behaviours predicted subordinates' job satisfaction most strongly. Expatriate managers expressing their management philosophies and experience shed light on the various aspects of adjustment and management of NGOs. In addition, review of Kenyan and Ethiopian cultures and the NGO context in these countries offers valuable information for expatriate managers. This study's general imphcation for Cross Cultural Management and lnternational Human Resources Management is that the combination of culture general and culture specific knowledge and reflections on Eastern Africa countries can inform senior management and international HR staff about the critical issue of what to include in training, coaching, and actual experience in a particular host country in order to ensure effective leadership. Furthennore, this knowledge is expected to influence expatriate managers' behaviour modification to enhance positive subordinate reactions. Questions about how to prepare expatriate managers and subordinates to work more competently and sensitively across cultures are addressed. Further theoretical implications, limitations of the study and directions for future research are also addressed.