Kyoto University (京都大学) / 0048 / 新制・論文博士 / 工学博士 / 乙第3022号 / 論工博第879号 / 新制||工||341 / 4590 / UT51-61-I254 / (主査)教授 上之園 親佐, 教授 板谷 良平, 教授 林 宗明 / 学位規則第5条第2項該当

Kyoto University (京都大学) / 0048 / 新制・論文博士 / 工学博士 / 乙第3026号 / 論工博第883号 / 新制||工||342 / 4594 / UT51-61-I258 / (主査)教授 大谷 泰之, 教授 板谷 良平, 教授 木嶋 昭 / 学位規則第5条第2項該当

Kyoto University (京都大学) / 0048 / 新制・論文博士 / 工学博士 / 乙第3028号 / 論工博第885号 / 新制||工||342 / 4596 / UT51-61-I260 / (主査)教授 古川 淳二, 教授 小野木 重治, 教授 河合 弘廸 / 学位規則第5条第2項該当

In this thesis I propose a practical framework for a feminist science by seeking to ground feminist theories in an understanding of the practice of science. There are two inter-linking themes. The first concerns relating feminist epistemologies of science to an understanding of how the practice of science is gendered. This understanding is then developed in the second theme, namely, feminist strategies for change. These issues are explored further in two empirical studies which investigate experiences and perceptions of the next generation of scientists (undergraduate science students) and women practitioners who are sympathetic to feminism and science. Part 1 reviews feminist literature that addresses the position of women in science, the relationships between gender and science, and feminist epistemologies of science. I identify, and explore empirically in Part 2, limitations in the various theories. These fall under two main headings. First, the relationship between male domination of science and masculinity, focusing in particular, on the social construction of masculinity within science and differences in scientific practice. Second, I investigate the gap between theory and practice in feminist epistemologies of science, covering four main issues: the role of the individual feminist scientist within the scientific community; the tension between relativism and objectivism in a feminist methodology; the organisation of a feminist science; and the relationship between a feminist scientific community and the wider society.

Thermal properties of graphene and graphite have been investigated by employing the analytical expressions for the phonon dispersion relations and the vibrational density of states derived by Nihira and Iwata, which are based on the semicontinuum model proposed by Komatsu and Nagamiya. The thermal conductivities of graphene and graphite are computed within the framework of Callaway’s effective relaxation time theory. The Normal-drift contribution (the correction term in Callaway’s theory) produces a significant addition to the result obtained from the single-mode relaxation time theory, clearly suggesting that the single-mode relaxation time approach alone is inadequate for describing the phonon conductivity of graphene. Its contribution to the thermal conductivity arises from the consideration of the momentum conserving nature of three-phonon Normal processes and is found to be very important for explaining the magnitude as well as the temperature dependence of the experimentally measured results for graphene and graphite. This model has not been implemented before for studying the thermal conductivity of graphene. Also the model has been applied to compute the thermal conductivity of graphene, graphite basal planes, and graphite c-axis. This has further been used to investigate the evolution of thermal properties from graphene to graphite as a function of layer thickness and temperature. The effects of isotopes and tensile strain on the graphene thermal properties have been examined within this model and compared with other available studies.

The application of social network analysis in animals has facilitated research into dynamic fission-fusion social systems. These have important implications for the evolution of individual social behaviour, and for population-level processes such as information transfer and disease dynamics. This thesis explores the assumptions behind using networks to study animal social systems in projects using individual-marking or biologging. It then applies these methods to study social structure in a study population of a long-distance migrant, the light-bellied brent goose. It provides new insights about the causes and consequences of social structure, and individual social strategies, in a fission-fusion social system in the context of a migratory cycle. We show that social networks have a strong spatial structure, but with additional non-randomness once these spatial constraints have been accounted for. However, individual social associations are seasonally dynamic. These social structures, and their seasonal dynamics, are highly stable between years. Furthermore, non-random associations have important implications for foraging success. Individuals foraging in more familiar flocks are able to spend more time feeding, and less time involved in aggressive interactions or vigilant. This results in social network position influencing the ability of some individuals to gain body condition during spring staging and leave for breeding grounds in better condition. These results highlight the importance of understanding social networks when investigating individual time-budgets in social foragers. They also emphasise the importance of establishing the link between individual status and social network position before drawing any conclusions about the role of social network position in explaining differences in fitness between individuals in fission-fusion social systems.

Women’s expeditionary work, in common with women’s geographical work more broadly, has been comparatively understudied within the history of geographical thought and practice, and within the wider discipline, until relatively recently (Domosh 1991a, 1991b; Rose 1993; Maddrell 2009a). This thesis, completed for a Collaborative Doctoral Award between the University of the West of England, and the Royal Geographical Society (with IBG), charts this terra incognita, and presents a reconstructed historical geography of women’s participation in RGS-supported expeditions between 1913 and 1970, taking as its start date the permanent admission of women to the Fellowship of the RGS. Building on earlier substantive feminist research into women’s historic geographical and expeditionary work (Maddrell, 2009a), it presents a systematic survey of all applications for RGS support during this period, drawing on a range of sources from across the RGS archives and collections. Prior to this doctoral study, this material had not been investigated for this purpose or in great depth, nor was there a complete record of the RGS’s support of expeditionary work during this period: this thesis presents a new and original database which can be used to research these questions. Drawing on these original findings, and on the extensive literatures around feminist historical geography, feminist epistemologies, the historiography of geographical thought and practice, as well as the recent literature on mobilities, this thesis investigates how women negotiated the networks in, around, and beyond the RGS to gain support for their expeditionary work. In particular, it highlights the importance of women-focused networks and familial-social networks for gaining this support. It also uses their participation in and embodied experiences of RGS-supported expeditions, including their expeditionary (im)mobilities and expeditionary relationships, to complicate existing understandings of expeditions as a male-dominated space, form, and practice of geographical knowledge production, thereby investigating the relationships between gender, subjectivity, and expeditionary knowledge production. Finally, it considers the dissemination and reception of their expeditionary knowledges within the spaces of the RGS.

Resonance Raman spectroscopy is a powerful technique that yields specific molecular information on samples under study. It has been used as a powerful tool to understand the structure and states of heme proteins. The vibrational bands of heme are well known. However, excitation wavelengths of 488 and 405 nm have not been used before to provide physiologically relevant information in terms of the concentration and state of heme proteins in cardiomyocytes. The aim of this study was to develop a novel technique, resonance Raman microspectroscopy, to investigate the cellular responses of cardiac myocytes to hypoxia and reoxygenation, and the mechanism of cardioprotective effect of nitric oxide donor in isolated ventricular cardiomyocytes exposed to metabolic inhibition and re-energisation. In order to understand the effect of the different environments on cells and hemoproteins, pre-resonance and resonance Raman tweezing microspectroscopy were applied to monitor the intracellular redox state of hemoglobin from single red blood cells. Further, hypoxia and reoxygenation in an isolated red blood cell were investigated using pre-resonance Raman tweezing and a microfluidic flow cell. Moreover, for the first time the effect of nitric oxide donor on single red blood cells under hyperoxic and hypoxic condations was investigated using Raman tweezing. In terms of cardiomyocytes, for the first time the results show that Raman microspectroscopy using an excitation wavelength of 488 nm can be used to: (1) characterize different cellular responses to reoxygenation of hypoxic cardiomyocytes, (2) investigate the difference between cardiomyocytes that did not recover contractility, and the other cell did recover contractility exposed to metabolic inhibtion and re-energisation, and (3) investigate the mechanism of cardioprotective effect of nitric oxide donor in isolated ventricular cardiomyocytes exposed to metabolic inhibition and re-energisation. A short wavelength of 405 nm was found to result in rapid damage to the cardiomyocytes.

The interaction of the solar wind with the near-Earth environment forms Earth's magnetosphere and drives a process called the Dungey Cycle. Birkeland currents are required to transmit stress within the system. This thesis uses large-scale, statistical analysis (both temporal and spatial) to examine their magnitude and spatial extent in the context of the Dungey Cycle. Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) data are processed; the methodology is described and the success rate examined before the regions 1 and 2 Birkeland current magnitudes are explicitly compared to dayside and nightside reconnection rate for the first time. The magnitudes of the currents are well-correlated with both, suggesting that magnetic reconnection on day and nightside is driving higher Birkeland current magnitudes. The behaviour of the R1 and R2 currents is examined in a superposed epoch analysis of 2900 substorms identified by SuperMAG. Both current systems increase in magnitude and spatial extent during the growth phase of a substorm, peaking shortly after expansion phase onset. This analysis yields new information about how the currents react to the substorm cycle. A seasonal and a diurnal variation in the Birkeland current magnitudes is described and linked to the effect of ionospheric conductance; this is explored further, and it is found that currents are well-described by multiplying the dayside reconnection rate by an number representing the global variation of conductance with UT. This thesis presents evidence that Birkeland current magnitudes are consistent with driving by ionospheric convection, which is in turn driven by magnetic reconnection on both the dayside and the nightside. It is also demonstrated that the current ovals measured by AMPERE expand and contract with magnetic reconnection as open flux is added to and removed from the polar cap. These insights are expanded upon with ideas for future research.

This thesis studies the characteristics of ultra low frequency (ULF) waves driven by recently-injected energetic particle populations gradient-curvature drifting azimuthally around the Earth. A statistical study of 83 separate substorm-driven ULF waves is undertaken in order to determine if the spatial proximity to the driving substorm affects the characteristics of the observed waves, as suggested by Yeoman et al. (2010). Waves were observed using Super Dual Auroral Radar Network (SuperDARN) radars and substorms identified using the Far Ultraviolet Imager (FUV) on-board the IMAGE spacecraft alongside a list of substorms provided by Frey et al. (2004). Azimuthal wave numbers, m, ranged in magnitude from 2 - 60 corresponding to particle energies, W, of ~1 - 70 keV. Phase propagation was always directed away from the location of the substorm and predicted particle energies were highest when closest to the substorm location in azimuth. This thesis also includes the study of three individual substorms, each with associated observations of multiple ULF waves using different SuperDARN radars. It is demonstrated that individual substorms are capable of driving a number of wave events characterised by different azimuthal scale lengths and wave periods, associated with different energies in the driving particle population. Similar trends in m and W are found to exist for multiple wave events with a single substorm as was seen in the single wave events of the statistical study. A recent case study event is included where substorm triggered ULF wave activity observed by two SuperDARN radars and observations of the particle populations responsible for driving the waves were observed using in-situ magnetospheric data from the Van Allen Probes. This conjunction of the recently-injected cloud of energetic ions with the probes allowed the study of the ion distribution functions which could then be compared to particle energies estimated using the characteristics of the waves.