The high-latitude electric eld fall-o region connects convection in the polar cap to the region where ring currents modify the penetration electric field equatorward of the polar cap boundary. This region is often overlooked because it falls between the limits of low latitude and high-latitude ionospheric models. However, penetrating electric fields cause large changes in ion composition; and therefore, correctly modeling the electric fields and plasma drift in this region aids in correctly specifying the ionosphere. Many ionospheric models use the Kp index as a physical driver, and so the latitude dependence of the plasma drift in the fall-o region was investigated as a function of Kp using Defense Meteorological Satellite Program ion drift data from the 2007{2010 solar minimum. Both the dusk and dawn sectors were analyzed and t to analytical functions describing the fall-o with decreasing latitude. The latitude dependencies were found to dier in the dusk and dawn sectors with a factor of two increase in the expansion of the duskside polar cap radius and auroral region over the dawnside. Additionally, the low-Kp polar cap radius was found to be five degrees smaller than the radius currently used in simple ionospheric models.

No description available.

Finite structure splitting (FSS) is a bottleneck for quantum dot (QD) based solid state entangled photon pair generator (EPPG) for Quantum Key Distribution (QKD) application. In QD, entangle photon pairs are generated through a cascaded emission process—biexciton to exciton to ground state. The FSS of the excitonic state destroys the entanglement of the photon pairs, hence needs to be eliminated. FSS can be tuned by engineering the crystal growth direction, varying dot shape or size, changing the material composition and/or applying external strain. Numerical investigation of FSS and designing of realistically-sized QD based EPPG demands multiscale-multiphysics many-body simulation efforts. To this end, in this work, we report the coupling of full configuration integration (FCI) method with the atomistic empirical tight-binding (TB) models (10-band sp3s* and 20-band sp3d5s*) to calculate the excitonic energetics and FSS in recently reported multimillion-atom III-V dot-in-nanowire structures. The core of the computational framework comprises two parts: i) NEMO3D, which, using the TB models, can compute single-electron energetics of multimillion-atom structures, and ii) An FCI kernel, which computes the many-particle energetics and wavefunctions using the single-electron outputs as derived from NEMO3D. NEMO3D is a broad platform that handles geometry construction, calculation of strain distributions and built-in potential fields, solving the Schrodinger’s equation and computing optical matrix elements. Three output files from NEMO3D are of particular importance for the FCI toolkit: i) Single-electron energy values, ii) Eigen functions, and iii) Relaxed atom positions of the device. FCI calculates the Coulomb and Exchange matrix elements associated with multi-particles and forms the many-body Hamiltonian. The excitonic states (electron-hole pair) are calculated by solving the many-body Hamiltonian and the value of FSS, if exists, is determined. Recently, nitride-based nanostructured devices have been found to be a promising candidate for single and entangled multi-photon emitter applications. The principal goal of this dissertation is to facilitate the numerical design of InGaN/GaN based dot-in-nanowire EPPG units. To this end, a number of kernels in NEMO3D and FCI packages were augmented. The geometry constructor in NEMO3D was extended for two non-polar planes of wurtzite crystal: m-plane and a-plane. It is found that these two non-polar planes, with much smaller built-in piezoelectric fields, exhibit improved optical transition probabilities than the polar c-plane counterpart. As test cases, light-emitters in dot-in-wire and multiple quantum well (MQW) configurations were simulated and compared in all three (c-plane, m-plane, and a-plane) growth directions. TCAD toolkits are used to simulate the terminal optical characteristics such as internal quantum efficiency (IQE) and spontaneous emission rate. Hexagonal-base truncated-pyramid shaped QD was also added to the NEMO3D geometry constructor as pyramid shaped dots offer directionality and better extraction efficiency of emitted photons, which is important for single or entangled photon generators. The FCI simulator was modified for calculating the excitonic states that involve an electron-hole pair. As for EPPG design, four device structures are considered: i) Disk-in-nanowire on the polar c-plane, ii) pyramid shaped dot-in-nanowire on polar c-plane, iii) Disk-in-nanowire on non-polar m-plane, and iv) Disk-in-nanowire on non-polar a-plane. Simulations are done for different disk thicknesses, material compositions, quantum dot shapes and crystal directions. Results and in-depth analysis are presented on the effects of these design parameters on many-body energetics e.g. binding energy, excitonic bandgaps and FSS. The derivation of excitonic transition probability from single-electron momentum matrix is discussed in detail. Finally, an EPPG design is proposed employing the entangled polarization profiles from two excitonic emissions.

Turmeric polar extract (TPE) was obtained by dielectric-precipitation of turmeric slurry and found to contain three proteins with two in the 10-11 KDa range being dominant. Antioxidative activity and persistence (AP) of TPE (5%, w/v) respectively showed 87% and 85% greater generation of alkoxy- and peroxyl radicals compared the non-redox-active buffer alone showing significant (p<0.05) pro-oxidative behavior. Conversely, purified curcumin (CU) (0.1% w/v) was dramatically antioxidative with AA and AP values of 2,828 and 1,129%, respectively, compared to the blank. However, a combination of the two at the same concentration dropped these values to 590 and 389%, respectively, reflecting dramatic dampening of the efficacy of CU. Ultraviolet radiation significantly modulated the efficacy of CU where UVB (300 nm) exposure gave the highest enhancement when limited to five min. Data showed that turmeric contains highly pro-oxidant polar proteins that significantly dramatically diminishes the beneficial antioxidative efficacy of its principal phytochemical, CU.

京都大学 / 新制・課程博士 / 博士(理学) / 甲第24438号 / 理博第4937号 / 新制||理||1705(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)教授 依光 英樹, 教授 若宮 淳志, 教授 畠山 琢次 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

This master thesis deals with conics in the real projective plane. The goal was to com- prehensibly introduce conics in the projective plane to high-school students and teachers. In order to fulfill this goal, the projective plane and homogenous coordinates were intro- duced, and harmonic set and priniple of duality were studied closely. The conics in the projective plane were approached from the perspective of history, and various definitions. Well-motivated introduction of a pole and a polar was emphasized.

Polar bears spend the majority of their lives on the sea ice, where they gain access to seals and mates. In western Hudson Bay, the sea ice melts for three to four months in the summer, and polar bears there are forced onto land. These bears live on their fat reserves for the duration of the iceless period, until temperatures get colder in the fall and freeze up begins. The aggregation of polar bears near Churchill, Manitoba during the ice free period has led to a thriving tourist industry, with a large influx of tourists visiting Churchill in the fall in a six to eight week period, yet little is known about the impacts of this industry on the biology of the bears. This study investigated the effect of tourist vehicles and human presence on the behavior of polar bears over the fall of 2003 and 2004. Overall time budgets were estimated for bears, and the behavior of males and females was compared. Females spent significantly less time lying and more time in locomotion than males. Time budgets were also estimated for bears in the presence and absence of tourist vehicles. Bears spent less time lying and more time in a sit/stand position in the presence of vehicles. Air temperature had no significant effect on the time budgets of polar bears. Tundra vehicle approaches were manipulated to determine effects on polar bear behavior, and to investigate any variables that significantly affected response, including habituation. A response was defined as any sudden whole body movement or change in position or behavior at the time of approach. A total of 25% of all bears responded to the experimental vehicle approach. For bears that responded to approach, the average distance at response was 43 m. The average speed of the vehicle was 0.66 ± 0.02 m/s (range 0.23 to 1.15 m/s). Approach variables that significantly influenced the likelihood of response of a bear to an approaching vehicle included angle of approach and vehicle speed. Direct approaches, in which the bear was in the path of the moving vehicle, had a higher probability of eliciting a response than indirect approaches, in which the vehicle stayed to one side of the bear at all times. Higher speeds of the vehicle increased the probability of a response by a bear. Behaviors of the bear that significantly predicted a response were shifting of the body and smacking of the lips. A playback study was conducted to determine the effects of human induced sound on polar bears. There was no significant effect of human sound on polar bears. Results presented here provide the first experimental evidence of variables in the tourist industry that affect polar bear behavior, and the first evidence of behavioral cues predicting a response to vehicle approach.

In this episode, we continue our discussion of line codes by examining five schemes used with polar and bipolar signaling: NRZ-L, NRZ-I, RZ-AMI, Manchester, and differential Manchester. We also discuss differential coding and its benefits.

Type IV pili (T4P) are protein filaments found on the surface of a variety of bacterial species and mediate biofilm formation, adhesion, and flagellum-independent twitching motility. The biogenesis of T4P is dependent on a cell envelope-spanning, multiprotein complex that localizes to the poles in rod-shaped cells. How these proteins localize and cross the peptidoglycan (PG) layer in the absence of dedicated PG-hydrolyzing enzymes is unknown. In P. aeruginosa, PilMNOP interact to form the alignment subcomplex, connected via PilP to PilQ, which forms the outer membrane secretin. We hypothesized that polar localization and integration of the T4P machinery was driven by ordered recruitment to future sites of cell division, placing assembly system components at division septa in the correct position before daughter-cell separation. To determine which T4P components are essential for localization of the complex, we fused the T4P inner membrane assembly protein PilO to the fluorescent protein mCherry to monitor its localization. mCherry-PilO localized to the cell poles and midcell in wild type bacteria. However, it was delocalized in a strain lacking PilQ. A PilQ-mCherry fusion localized to the cell poles, likely through its putative septal PG binding AmiN domains, suggesting that PilQ binds PG and thus localizes its partners to future sites of cell division. In the absence of the associated pilotin protein (PilF), which is required for PilQ multimerization in the OM, T4P components were polarly localized, implying that localization is not dependent on secretin formation. The results of this research support a pre-installation mechanism for integration of protein complexes in the gram negative cell envelope without PG hydrolysis, which may be applicable to other systems. / Thesis / Master of Science (MSc)

Microbial communities play critical roles in biogeochemical cycles of aquatic and terrestrial ecosystems, but studies of soil microbial communities have been limited by the diversity and complexity found in most ecosystems. Here we report on work investigating the functional diversity of microbial mat and underlying soil communities in the McMurdo Dry Valleys of Antarctica across a gradient of phosphorus availability on glacial tills of distinct age and mineral composition in Taylor Valley, Antarctica. Microbial mat and soil DNA were extracted and sequenced on an Illumina NextSeq500 in a 150 bp paired end format. Raw sequences were uploaded to the MG-RAST server for processing and annotation. Community taxonomic and functional annotation were determined using the RefSeq and SEED Subsystem databases, respectively. The results revealed significant variation in microbial mat community taxonomic composition between the two tills, strongly associated with visual assessment of mat morphology, e.g., "black" and "orange" mats, and soil N:P ratios. The underlying soil microbial communities did not exhibit significant differences in diversity between the two tills, but community composition varied significantly across gradients of soil chemistry, particularly extractable-phosphate content even within tills. The relative abundance of biogeochemistry-relevant pathways determined from the SEED database varied amongst soil microbial communities between the two tills. For example, microbial mat communities exhibited significant variation in the relative abundance of key nitrogen and phosphorus metabolism associated genes strongly associated with the underlying soil N:P. These results suggest that spatial variation in geochemistry influences the distribution and activity of microbial mats, but that the microbial mats themselves also exert a significant homogenizing effect on the underlying soil communities and some of the key biogeochemical processes they facilitate. / Master of Science / Microbial communities play critical roles in the processes of aquatic and terrestrial ecosystems. Still, studies of soil microbial communities have been limited by the complex nature of the ecosystems we study. This study examined the diversity of microbial communities in the McMurdo Dry Valleys of Antarctica, specifically looking at how different levels of phosphorus availability in the soil affected microbial function. We used DNA sequencing and databases to determine the taxonomic and functional makeup of these communities. We found that while the microbial mat communities varied significantly based on soil chemistry and appearance, the underlying soil microbial communities did not. We also found evidence suggesting that the microbial mats played a role in regulating some of the key ecosystem processes in the soil. Overall, this study sheds light on how microbial communities are impacted by their environment and how they, in turn, impact their surroundings.