3 resultados para Information science

em CORA - Cork Open Research Archive - University College Cork - Ireland


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This study explores the topic of leadership as perceived and practised by public library leaders. Library leaders have a wide-ranging impact on society but have been largely overlooked as the subject of serious study. Prior to this study, only one small interview-based study and five survey-based studies have been undertaken on public library leaders/leadership — all in North America. No study on the topic has been researched and published outside of North America. The current study is the most in-depth study to date, drawing on face-to-face interviews with thirty public library leaders. As this study was undertaken in three national jurisdictions — Ireland, Britain, and America — it is also the first transnational study on the topic. The study investigates library leaders’ perceptions of leadership, and critically explores if head librarians distinguish classic leadership from management practices, both conceptually and in their work lives. In addition to exploring core leadership issues, such as positive or negative traits, the study also investigates the perceptions of library leaders on matters closely connected with their careers. The study investigates the impact of public library leaders on their followers and on the broader society they serve. This study of the perceptions of senior public library leaders, across national boundaries, makes a theoretical contribution not just to leadership in librarianship, but also to the broader theory of library and information science, and in a limited way to the broad corpus of literature on organizational leadership. The study aims to develop an understanding of the perceptions of current leaders in the field of public librarianship. The results of the study show that leadership is a relatively scarce quality in public libraries in Ireland, Britain, and America. Many public library leaders focus on management and administration issues rather than leadership. The study also illustrates that varying leadership styles are practised by the interviewed librarians, and that there are no universal or common traits, even within national boundaries, for effective public library leadership. The implications of the study for both practising librarians and research literatures in librarianship and organizational leadership are also explored and a future research agenda developed.

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Practical realisation of quantum information science is a challenge being addressed by researchers employing various technologies. One of them is based on quantum dots (QD), usually referred to as artificial atoms. Being capable to emit single and polarization entangled photons, they are attractive as sources of quantum bits (qubits) which can be relatively easily integrated into photonic circuits using conventional semiconductor technologies. However, the dominant self-assembled QD systems suffer from asymmetry related problems which modify the energetic structure. The main issue is the degeneracy lifting (the fine-structure splitting, FSS) of an optically allowed neutral exciton state which participates in a polarization-entanglement realisation scheme. The FSS complicates polarization-entanglement detection unless a particular FSS manipulation technique is utilized to reduce it to vanishing values, or a careful selection of intrinsically good candidates from the vast number of QDs is carried out, preventing the possibility of constructing vast arrays of emitters on the same sample. In this work, site-controlled InGaAs QDs grown on (111)B oriented GaAs substrates prepatterned with 7.5 μm pitch tetrahedrons were studied in order to overcome QD asymmetry related problems. By exploiting an intrinsically high rotational symmetry, pyramidal QDs were shown as polarization-entangled photon sources emitting photons with the fidelity of the expected maximally entangled state as high as 0.721. It is the first site-controlled QD system of entangled photon emitters. Moreover, the density of such emitters was found to be as high as 15% in some areas: the density much higher than in any other QD system. The associated physical phenomena (e.g., carrier dynamic, QD energetic structure) were studied, as well, by different techniques: photon correlation spectroscopy, polarization-resolved microphotoluminescence and magneto-photoluminescence.

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This thesis is focused on the synthesis and solid state analysis of carbohydrate derivatives, including many novel compounds. Although the synthetic chemistry surrounding carbohydrates is well established in the literature, the crystal chemistry of carbohydrates is less well studied. Therefore this research aims to improve understanding of the solid state properties of carbohydrate derivatives through gaining more information on their supramolecular bonding. Chapter One focuses on an introduction to the solid state of organic compounds, with a background to crystallisation, including issues that can arise during crystal growth. Chapter Two is based on glucopyranuronate derivatives which are understudied in terms of their solid state forms. This chapter reports on the formation of novel glucuronamides and utilising the functionality of the amide bond for crystallisation. TEMPO oxidation was completed to form glucopyranuronates by oxidation of the primary alcohol groups of glucosides to the carboxylic acid derivatives, to increase functionality for enhanced crystal growth. Chapter Three reports on the synthesis of glucopyranoside derivatives by O-glycosylation reactions and displays crystal structures, including a number of previously unsolved acetate protected and deprotected crystal structures. More complex glycoside derivatives were also researched in an aim to study the resultant supramolecular motifs. Chapter Four contains the synthesis of aryl cellobioside derivatives including the novel crystal structures that were solved for the acetate protected and deprotected compounds. Research was carried out to determine if 1-deoxycellodextrins could act as putative isostructures for cellulose. Our research displays the presence of isostructural references with 1-deoxycellotriose shown to be similar to cellulose III11, 1-deoxycellotetraose correlates with cellulose IV11 and 1-deoxycellopentose shows isostructurality similar to that of cellulose II. Chapter Five contains the full experimental details and spectral characterisation of all novel compounds synthesised in this project and relevant crystallographic information.