Rozprawy doktorskie na temat „Dún Laoghaire (Ireland)”

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2011.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student submitted PDF version of thesis.
Includes bibliographical references.
Nitrous oxide (N₂O) is a significant greenhouse gas and main contributor to stratospheric ozone destruction. Surface measurements of N₂O mole fractions have been used to attribute source and sink strengths, but large uncertainties remain. Stable isotopic ratios of N₂O (here considered ¹⁴N¹⁵N¹⁶O, ¹⁵N¹⁴N¹⁶O, ¹⁴N¹⁴N¹⁸O, relative to the abundant ¹⁴N¹⁴N¹⁶O) linked to source and sink isotopic signatures can provide additional constraints on emissions and counter-balancing stratospheric sink. However, the isotopic composition in the troposphere has been regarded and measured as a fixed value, limited by insufficient measurement precision and few data. This thesis provides the foundation for high-frequency, high-precision measurements and utilization of N₂O tropospheric isotopic composition. This is achieved through the development of a new measuring capability with sufficient precision to detect the subtle signals of N₂O isotopic composition in tropospheric air and uniquely fully-automated and high-frequency capable. This instrument was applied to produce the first set of tropospheric air observations gathered at a remote research station covering a full annual cycle, paired with air origin information, and providing a valuable assessment of tropospheric composition and its potential utility. The first regional model of tropospheric N₂O isotopic composition was developed for further assessment of expected variability and utility of isotopic composition data. The optimized fully-automated, liquid-cryogen-free pre-concentration device coupled to continuous flow IRMS resulted in ¹⁵N site-specific precisions markedly improved over other systems of 0.11 and 0.14 0/00 (1[sigma]) for [delta]¹⁵N[alpha] and [delta]¹⁵Nbulk, respectively, and among the best bulk composition precisions of 0.05 and 0.10 0/00 for [delta]¹⁵Nbulk and [delta]¹⁸O, respectively. The high-precision, non-continuous flask observations of N₂O ¹⁵N site-specific composition (January 2010 to January 2011; Mace Head Atmospheric Research Station, Ireland) detected statistically significant signals on short-term and annual timescales, and when analyzed with air history information showed consistencies with source-receptor relationships. No seasonal cycle could be detected in the low-frequency observations, but regional model scenarios of the stratospheric seasonal signal resulted in amplitudes at the cusp of current measurement capabilities. This thesis illustrated detectable variations in tropospheric N₂O isotopic composition which can potentially reduce uncertainty in the N₂O budget with high-frequency, high-precision observations, now feasible by the instrumentation developed here.
by Katherine Ellison Potter.
Ph.D.

Written in c. 700 at the island monastery of Iona, Adomnán’s Vita Sancti Columbae (VSC) is an important source for the study of early medieval Scotland and Ireland. This thesis analyses the text as a literary work, seeking to understand more about its internal logic and the ways in which it relates to other kinds of literary texts. These include Biblical texts, other early insular, continental and late antique hagiographies, vernacular secular sagas, legal texts, scholarly literature and wisdom literature. Adomnán did not necessarily know all of these texts, and some of them post-date him, but they provide a wider interpretative context for VSC. Adomnán’s other known work, De Locis Sanctis, and texts connected to him, such as Cáin Adomnáin, will also be considered. I look for points of similarity and divergence between Vita Sancti Columbae and these other texts, which I term “adjacent literature”, looking to see how the text relates to its wider literary and intellectual context. By taking this approach, we are able to understand the text better on its own terms, making it more useful as a source for historical study. The text is studied, and set within its wider context, with respect to the following main areas: The Manuscripts of Vita Sancti Columbae: the visual construction of the text: Considering the five surviving manuscripts of the first recension of VSC, but focussing especially on the earliest (Schaffhausen Stadtbibliothek Generalia 1, of near authorial date and Ionan provenance), this chapter considers how the visual presentation of VSC relates to its production and reproduction as a literary text. Page layout, illumination, the use of the Greek alphabet and different colours of ink and manuscript context are all discussed. Structure and Narrative Sequencing in Vita Sancti Columbae: VSC is not a chronologically-structured account of Columba’s life, but rather a hagiography made up of many short narratives that demonstrate his sanctity and power in different ways. These narratives are arranged thematically, with a basic tripartite structure, with one book concerned with prophecies, one with miracles and one with visions. The narratives within the three books are often arranged into small, tightly constructed clusters of related stories. This chapter is an investigation of both the overall structure of the work and the “micro-structure” of the sequencing of narratives. Language and Vita Sancti Columbae: This chapter explores Adomnán’s style as a Hiberno-Latin writer, including discussions of such techniques as hyperbaton, alliteration and variatio. Adomnán’s use of and attitudes to Greek and Hebrew are also explored, as is his use of and attitudes to Old Irish. Sex, Women and Violence in Vita Sancti Columbae: This chapter investigates Adomnán’s presentations of sexual behaviour, the role of women as givers of advice, and the violence inflicted on the innocent. Several of the narratives about violence clearly have a strong gendered dimension, and relate in interesting ways to Cáin Adomnáin, and they are discussed in this light. Dangerous Beasts in Vita Sancti Columbae: VSC contains several encounters with dangerous beasts of various kinds, some of which are not unambiguously identifiable. These episodes are studied in turn, including discussions about identifying the beasts, and investigating the functions that they have within the text. Vita Sancti Columbae and Cult Practice: The thesis concludes with an exploration of the roles VSC might have played in the life of the Columban familia. The use of blessed objects and relics within the text is studied, with suggestions as to their relation to cult practice. The final section concerns the possibility that certain parts of VSC were intended to be used in processions, or to be read with the active participation of an audience.