京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21732号 / 工博第4549号 / 新制||工||1709(附属図書館) / 京都大学大学院工学研究科電気工学専攻 / (主査)教授 大村 善治, 教授 松尾 哲司, 教授 竹内 繁樹 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

The overarching aim of this research was to understand factors implicated in the maintenance of rumination and worry, conceptualised as a transdiagnostic process of repetitive negative thought (RNT), through the use of cross-sectional, prospective, and experimental research designs. Rumination and worry have been repeatedly implicated in the development and maintenance of various forms of psychopathology, in particular, depression and anxiety disorders. Given the negative outcomes for mood and psychopathology, there is a need for a better understanding of vulnerability factors that maintain this unconstructive thinking. Based on a review of the literature, an integrative theoretical model was developed and tested using structural equation modelling. Using cross-sectional data, the model was tested in a large sample of adults (n = 506). Of the broad range of proximal and distal vulnerability factors examined, only neuroticism and beliefs about the function of repetitive thought remained significantly associated with RNT once current symptoms were statistically controlled. Emotional abuse and abstract processing were indirectly associated with RNT. Following on from this, a prospective study examined which of these vulnerability factors prospectively predicted change in RNT over six to eight weeks. Only neuroticism and the specific belief that repetitive thought aids instrumental understanding predicted change in RNT, after controlling for depression and anxiety symptoms. Next, two experimental studies were conducted to explore the causal relationship between RNT and the belief that RNT aids insight and understanding, by experimentally manipulating this appraisal and measuring the impact on state RNT. Whilst methodological issues with the first experimental study precluded clear conclusions being drawn about the nature of the relationship, the second experimental study demonstrated that participants manipulated to believe that RNT is helpful for increasing insight and understanding had greater levels of state RNT after exposure to a stressor, relative to participants manipulated to believe that RNT is unhelpful. Finally, in order to see whether rumination has any consequences that may potentially reinforce its further use, an experimental study was conducted to manipulate processing mode (abstract rumination versus concrete thinking) and examine the effect on a range of outcomes relating to insightfulness and avoidance. Whilst rumination did not lead to increased insight, it did afford more justification for avoidance, relative to concrete thinking. The clinical and theoretical implications of these findings are discussed with respect to existing theories of repetitive negative thought.

Due to the interesting financial moment we are living, my motivations to write this Master thesis has mostly been the behavior of interest rates and models that can be used predict them. Thus, in this dissertation I have presented theHull-White model and the way to calibrate it against market data so it can be used to price interest rate derivatives. The reader can find both theoretical and practical presentations and examples along with the code to program them byhim/herself.

The aim of this project was to improve the imaging performance of planar superlenses for evanescent near-field lithography. An experimental investigation of the performance of superlenses with reduced surface roughness was proposed. Such an investigation poses significant requirements in regards to process control in thin film deposition of silver onto dielectric substrates. Thin film deposition of silver films, onto silicon dioxide substrates, achieved films with root mean square surface roughness as low as 0.8 nm. While these experiments provided good understanding of the deposition process, significant variability of the surface roughness parameter remained an issue. The diffculty of achieving consistent control of surface roughness led to a finite element method simulation study where this parameter could be readily controlled. An improved understanding of how surface roughness affects superlens imaging performance was obtained from the results of this investigation. Furthermore, it was shown that in order to conduct an experimental investigation to verify the simulation results, it would be necessary to improve the imaging capability of super-resolution lithography protocols to achieve 3σ line edge roughness (LER) of <20 nm. Resist-scheme optimisation was identied as an important factor in this regard. Thus, a novel calixarene-based photoresist was formulated and characterised. The resist demonstrated superior imaging capabilities through interference lithography and evanescent near-field optical lithography, capable of resolving 250-nm period half-pitch line gratings with 3σ LER below 10 nm. The development of this novel photoresist will enable future lithographical investigations to be conducted with improved resolution and imaging fidelity.

No description available.

Conventional passive metamaterials always suffer from the limitation of loss and dispersion due to fundamental causality issue. Especially it becomes severe due to material loss at terahertz frequency. Our work resolves the loss problem by introducing gain device into the metamaterial structure. A passive volumetric metamaterial is firstly designed on the quartz substrate. A negative resistance is inserted into the wire of the structure to provide the gain. We have identified resonant tunneling diodes that work up into THz frequency and shown in simulation that simultaneous negative index and gain can be obtained.

Bacterial endosymbionts occur in diverse fungi, including members of many lineages of Ascomycota that inhabit living plants. These endosymbiotic bacteria (endohyphal bacteria, EHB) often can be removed from living fungi by antibiotic treatment, providing an opportunity to assess their effects on functional traits of their fungal hosts. We examined the effects of an endohyphal bacterium (Chitinophaga sp., Bacteroidetes) on substrate use by its host, a seed-associated strain of the fungus Fusarium keratoplasticum, by comparing growth between naturally infected and cured fungal strains across 95 carbon sources with a Biolog((R)) phenotypic microarray. Across the majority of substrates (62%), the strain harboring the bacterium significantly outperformed the cured strain as measured by respiration and hyphal density. These substrates included many that are important for plant-and seed fungus interactions, such as D-trehalose, myoinositol, and sucrose, highlighting the potential influence of EHB on the breadth and efficiency of substrate use by an important Fusariurn species. Cases in which the cured strain outperformed the strain harboring the bacterium were observed in only 5% of substrates. We propose that additive or synergistic substrate use by the fungus bacterium pair enhances fungal growth in this association. More generally, alteration of the breadth or efficiency of substrate use by dispensable EHB may change fungal niches in short timeframes, potentially shaping fungal ecology and the outcomes of fungal-host interactions.

Negative emotions can be challenging to regulate, and for some individuals can lead to failures of behavior regulation. The present study is an initial effort to explore the role that mindfulness may play in fostering effective behavior regulation among those prone to high negative urgency (NU). Eighty undergraduate students were recruited based on their high or low scores of NU. First, participants completed a self-report measure of mindfulness (Mindful Attention Awareness Scale; MAAS), an Emotional Go/No Go task in an fMRI scanner, and then reported alcohol consumption. Results showed that those with high in NU had low levels of mindfulness compared to those low in NU. Mindfulness predicted substance use at the one- month follow-up after controlling for the predictive roles of NU and gender. Further exploration of the underlying neural mechanisms of mindfulness is needed to better understand its impact on emotion- and self-regulatory processes, especially during difficult emotional experience.

Reverse thrust operations of a model scale Contra-Rotating Open Rotor design were numerically modelled to produce individual rotor thrust and torque results comparable to experimental measurements. The aims of this research were to develop an understanding of the performance and aerodynamics of open rotors during thrust reversal operations and to establish whether numerical modelling with a CFD code can be used as a prediction tool given the highly complex flowfield. A methodology was developed from single rotor simulations initially before building a 3D‘frozen rotor’ steady-state approach to model contra-rotating blade rows in reverse thrust settings. Two different blade pitch combinations were investigated (β1,2 =+30°,- 10° and β1,2 =-10°,-20°). Thrust and torque results compared well to the experimental data and the effects of varying operating parameters, such as rpm and Mach number, were reproduced and in good agreement with the observed experimental behaviour. The main flow feature seen in all the reverse thrust cases modelled, both single rotor and CROR, is a large area of recirculation immediately downstream of the negative pitch rotor(s).This is a result of a large relative pressure drop region generated by the suction surfaces of the negative pitch blades. An initial 3D unsteady sliding-mesh calculation was performed for one CROR reverse thrust case. The thrust and torque values were in poor agreement with experimental values and the disadvantages relating to time costs and required computational resources for this technique were illustrated. However, the results did yield a nominal unsteady variation of thrust and torque due to rotor phase position. Overall the work shows that it may be possible to develop a CROR reverse thrust prediction tool of beneficial quality using CFD models. The research also shows that the frozen rotor approach can be adopted without undermining the fidelity of the results.

Binge Eating Disorder (BED) is characterized by recurrent episodes of binge eating without the use of compensatory behaviors. Functional accounts of BED propose that negative affect is an antecedent to binge eating because binge eating serves to alleviate negative affect. However, previous studies investigating the association between negative affect and binge eating have yielded inconsistent findings, perhaps due to individual vulnerability factors that moderate the effects of negative affect on binge eating behavior. As one candidate, the current study investigated emotion regulation strategies that may be implicated in the maintenance of binge eating in BED, particularly under conditions of negative affect: brooding rumination, distress tolerance, and mood-related expectancies for eating. These emotion regulation strategies were: a) compared in 38 women with BED vs. 36 non-eating disordered female controls, b) examined in relation to markers of current binge eating severity among BED women, and c) used as predictors of caloric intake and urge to eat in response to a personally-relevant dysphoric mood induction upon presentation of snack foods in a "taste task." Results revealed that women with BED endorsed higher brooding rumination, more positive expectancies that eating serves to ameliorate negative affect, and lower distress tolerance than controls. Among women with BED, higher brooding rumination was associated with greater binge eating severity, and stronger expectancies that eating reduces negative affect were associated with more frequent binge eating episodes and greater urge to eat in response to depression. Surprisingly, better distress tolerance was associated with more frequent binge eating episodes. Women with BED consumed more calories and reported greater loss of control as well as a greater sense of guilt in response to the taste task relative to control participants. Contrary to hypothesis, there were no direct or indirect effects of any of the three emotion regulation strategies on change in urge to eat or calories consumed on the taste task following sad mood induction in BED women. In controls, better distress tolerance and stronger expectancies that eating alleviates negative affect were associated with decreased caloric intake on the taste task after mood induction. Overall, these findings highlight the importance of considering trans-diagnostic processes in BED as well as the need to identify other theoretically-relevant factors that contribute to the cognitive and behavioral features of BED. Limitations and directions for future studies are discussed.