The effect of ultraviolet-B radiation enhancement upon the competitive interactions of two species pairs was studied in the field. Wheat (Triticum aestivum L. 'Bannock') was paired with wild oat (Avena fatua L.) and jointed goatgrass (Aegilops cylindrica Host) to represent competition between species pairs in agricultural situations. Specially modulated ultraviolet lamp systems provided either low ultraviolet-B enhancement (simulation of a 16 % ozone layer reduction based upon the generalized plant action spectrum), high ultraviolet-B enhancement (40 % ozone reduction) or control (ambient solar ultraviolet-B) irradiance. Ultraviolet-B radiation enhancement significantly altered the competitive interactions of the species pairs. However, ultraviolet-B enhancement did not affect total shoot biomass production 1n the mixtures or shoot biomass production of the species 1n monoculture. The direction 1n which competitive interactions were altered appeared to be dependent upon the time at which the seeds were planted. Also, water stress affected some aspects of the interaction between ultraviolet-B enhancement and plant competition but the manner of this effect was inconsistent. Reproductive effort of the species was generally not affected by ultraviolet-B enhancement, except in wild oat plants under interspecific competition.

Tropical regions currently receive the highest global levels of solar ultraviolet-B radiation (UV-B, 280-320 nm) even without ozone depletion. Thus, the influence of natural, present-day UV-B irradiance in the tropics was examined for five tropical species, including three native rainforest tree species and two economically important species. Solar UV-B radiation conditions were obtained vi using either a UV-B excluding plastic film or a near-ambient UV-B transmitting film in a small clearing on Barro Colorado Island (BCI), Panama (9 ° N). Significant differences were often exhibited as increased foliar UV-B absorbing compounds, increased leaf mass per area, and reduced leaf blade length for plants receiving solar UV-B radiation. Plant height was typically reduced under solar UV-B, but some variation among species in response was seen. Biomass and photosystem II function using chlorophyll fluorescence were generally unaffected. The results of this study provide strong evidence that tropical vegetation, including native rainforest species, responds to the present level of natural solar UV-B. This suggests that even a small increase in UV-B radiation with ozone depletion may have biological implications.

Leaf epidermal transmittance of ultraviolet radiation (280-400 nm) was examined in several plant species to determine the capability of the epidermis to attenuate solar ultraviolet radiation. Epidermal samples were mechanically isolated and examined with a spectroradiometer/integrating sphere for transmittance. A survey of 25 species exposed to natural insolation was conducted. Although the species differed in life form, habitat type, and epidermal characteristics, epidermal transmittance was generally less than 10%. Ultraviolet radiation was attenuated 95 to 99% in more than half of the species. In 16 species, flavonoid and related pigments in the epidermis accounted for 20 to 57% of the attenuation. Several species exposed to supplemental ultraviolet irradiation (288-315 run) in a greenhouse exhibited significant (p≤0.05) depressions in epidermal transmittance of 31 to 47%, apparently resulting from an increase in ultraviolet-absorbing pigments.

The severity of stratospheric ozone depletion in the temperate and polar latitudes has raised concerns about the sensitivity of terrestrial vegetation and ecosystems to solar ultraviolet (UV-B) radiation. This dissertation examined the responses of plants and microbes to solar UV-B for 3 years in Tierra de! Fuego, Argentina (55° S). This region is under the influence of the Antarctic "ozone hole" during the austral spring. Additionally, a quantitative review of the UV-B literature was conducted using a set of statistical techniques known as meta-analysis. For the field studies in Tierra de! Fuego, plots were established in a Sphagnum moss peatland and a Carexsedge fen during the spring of 1996. These plots received either near-ambient solar UV-B (90% of ambient) or reduced UV-B (20% of ambient) using specially designed plastic films. At the end of the first field season, no effects of the solar UV-B treatments were apparent on the growth and pigmentation of the plant species in either community The height growth of the moss Sphagnum mageffanicum was less under near-ambient solar UV-B than reduced UV-B during the second and third growing seasons. In contrast, volumetric density of the moss was greater under nearambient UV-B. The growth of the vascular plants did not respond to the solar UV-B treatments even after 3 years although UV-B-absorbing compounds were greater under near-ambient UV-B in some species. Populations of testate amoebae (i.e., shelled amoebae) inhabiting S. magellanicum had greater numbers under near-ambient UV-B than reduced UV-B throughout the 3 years. This response may be an indirect effect of solar UV-B mediated by the direct effect of UV-Bon S. mageffanicum height growth. Fungi on the leaf surfaces of the tree Nothojagus antarctica appeared to be directly inhibited by solar UV-B. The quantitative literature review of plant field studies simulating stratospheric ozone depletion assessed the effects of elevated UV-B on 10 plant response variables from papers published between 1976 and mid-1999. Modest significant inhibitions of leaf area, aboveground biomass, and plant height were apparent due to increased UV-B using meta-analysis. An increase in UV-B-absorbing compounds appears to be the most robust general response to increased UV-B radiation.

Brown trout (Salmo trutta), demonstrated an avoidance response to a range of intensities of artificial ultraviolet radiation in a laboratory setting. UV field measurements were made under a variety of riparian canopies in a mountain river system. UV values at various depth regimes were compared with laboratory response values. Results suggested that ultraviolet light could be a factor in the absence of brown trout in particular habitat types at various times during the daylight hours. Visible light intensity response values were also obtained under the same experimental and field conditions. These data suggested that visible light also could be a contributing factor in the absence of brown trout in different habitat types. Visible light may be of equal importance to ultraviolet light in eliciting an avoidance response in brown trout.

The circumgalactic medium (CGM) is thought to contain the massive reservoir of gas exchanged over the course of galactic evolution, including the fuel for future star formation and the remnants of a galaxy’s merger history. Models and observations suggest that the CGM has a very low density, and faint optical or UV emission from this gas is exceedingly difficult to detect. This thesis is a combination of simulations, instrumentation and observations aimed at ultimately understanding the distribution and kinematics of ionized gas in the CGM. We present a suite of small-box hydrodynamic simulations created to study the interaction between smooth gas inflow and supernovae-driven outflow at the disk-halo interface where the galactic disk transitions into the CGM. They track the fate and kinematic evolution of gas accreting onto the galactic disk and find evidence of partial mixing with the enriched outflow. We use equilibrium photoionization models to create mock surface brightness maps of Ha and OVI emission. These observables motivate the need for new instrumentation and in suit, we present the newly commissioned Circumgalactic Ha Spectrograph (CHaS): a custom integral field unit (IFU) spectrograph tailored to detect low-surface brightness optical emission in the low-redshift universe. CHaS is deployed in the focal plane of the MDM Observatory Hiltner 2.4-meter telescope, conducting wide-field (10' x 10') spectral imaging with a competitive survey speed proportional to the high instrument grasp. A microlens array segments the field of view into > 60,000 spectra with a spatial resolution of 2.6'' and a resolving power of R ~ 10,000. Accordingly, CHaS is capable of resolving structure on scales less than 1 kpc (at 10 Mpc) and distinguishing emission lines separated by less than 40 km/s. As designed, a 50-100h exposure with CHaS would be the deepest H-alpha image and velocity field ever obtained, reaching a surface brightness of a few mR on scales of a few arcmin. Shorter, hour-long integrations with CHaS reveal a detailed map of the denser interstellar medium and bright emission at the disk-halo interface. We present results for three early commissioning targets: NGC 4631, NGC 7331 and NGC 1068, including high-resolution velocity maps and detections of new extended emission line regions far into the halo. We report a previously unnoted ribbon of ionized gas around NGC 1068, extending tens of kpc from the galactic disk beyond the known outer filamentary structure. Ongoing observations will provide a deeper probe of ionized gas far into the CGM of many nearby galaxy targets, detecting faint extended emission and mapping the velocity of ionized gas beyond the disk.

<p>Analysis of explosives (intact and post-blast) is of interest to the forensic science community to qualitatively identify the explosive(s) in an improvised explosive device (IED). This requires high sensitivity, selectivity, and specificity. Forensic science laboratories typically utilize visual/microscopic exams, spectroscopic analysis (e.g., Fourier Transform Infrared Spectroscopy (FTIR)) and gas chromatography/mass spectrometry (GC/MS) for explosive analysis/identification. However, GC/MS has limitations for explosive analysis due to difficulty differentiating between structural isomers (e.g., 2,4-dinitrotoluene, 2,5-dinitrotoluene and 2,6-dinitrotoluene) and thermally labile compounds (e.g., ethylene glycol dinitrate (EGDN), nitroglycerine (NG) and pentaerythritol tetranitrate (PETN)) due to mass spectra with very similar fragmentation patterns. </p><p>The development of a benchtop vacuum ultraviolet spectrometer coupled to a gas chromatography (GC/VUV) was developed in 2014 with a wavelength region of 120 nm to 430 nm. GC/VUV can overcome limitations in differentiating explosive compounds that produces similar mass spectra. This work encompasses analysis of explosive compounds via GC/VUV to establish the sensitivity, selectivity, and specificity for the potential application for forensic explosive analysis. Nitrate ester and nitramine explosive compounds thermally decompose in the VUV flow cell resulting in higher specificity due to fine structure in the VUV spectra. These fine structures originate as vibronic and Rydberg transitions in the small decomposition compounds (nitric oxide, carbon monoxide, formaldehyde, water, and oxygen) and were analyzed computationally. The thermal decomposition process was further investigated for the determination of decomposition temperatures for the nitrate ester and nitramine compounds which range between 244 ºC and 277 ºC. Nitrated compounds were extensively investigated to understand the absorption characteristics of the nitro functional group in the VUV region. The nitro absorption maximum appeared over a wide range (170 - 270 nm) with the wavelength and intensity being highly dependent upon the structure of the rest of the molecule. Finally, the GC/VUV system was optimized for post-blast debris analysis. Parameters optimized include the final temperature of a ramped multimode inlet program (200 ºC), GC carrier gas flow rate (1.9 mL/min), and VUV make-up gas pressure (0.00 psi). The transfer line/flow cell temperature was determined not to be statistically significant.</p><br>

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18229号 / 工博第3821号 / 新制||工||1585(附属図書館) / 31087 / 京都大学大学院工学研究科電子工学専攻 / (主査)教授 川上 養一, 教授 北野 正雄, 教授 木本 恒暢 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第20702号 / 工博第4399号 / 新制||工||1683(附属図書館) / 京都大学大学院工学研究科材料工学専攻 / (主査)教授 杉村 博之, 教授 河合 潤, 教授 邑瀬 邦明 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

Continuous increases in the interest and implementation of wastewater reuse due to intensified water stress has escalated the concerns of emerging contaminants. Among emerging contaminants there are microbial (antibiotic resistance) and chemical (pharmaceuticals) elements which have been shown to survive wastewater treatment. This dissertation aims to mitigate emerging contaminants by means of understanding and/or developing the appropriate disinfection strategies, with the intention to provide knowledge that would facilitate towards safe and sustainable water reuse. The first part of this thesis explored microbial risk component of antibiotic resistance. Antibiotic resistance genes are abundant in treated wastewater, and only pose a risk if taken up by potential pathogens through natural transformation. Our results showed that solar irradiation can double natural transformation rates, mediated by reactive oxygen species generation, which led to upregulation in DNA repair and competence genes in Acinetobacter baylyi ADP1. Treatment with UV-C254 nm irradiation also resulted in upregulation in DNA repair genes, nevertheless we observed a decrease in natural transformation rates. These results imply that direct damage of antibiotic resistance genes (ARG) could inhibit their spread and therefore risk, despite other factors contributing to the contrary. The next chapter in this dissertation postulated that the UV/H2O2 combination would be ideal to treat microbial and chemical emerging contaminants in effluent generated from an anaerobic membrane bioreactor. We demonstrated that at an optimal UV intensity and H2O2 concentration, we were able to achieve a 2 and 6-log reduction of the two antibiotic resistance genes and bacteria and used in this study, respectively, and more than 90% removal of the three pharmaceutical compounds. These observations suggest that UV/H2O2 has great potential in treating effluent with high nitrogen concentrations, preserving the fertilization benefit of AnMBR effluent. Overall, this dissertation revealed the potential of UV-based treatments for treated wastewater intended for reuse. Post-membrane processes effluent allows one to deploy UV-C254 nm to selectively target DNA and therefore ARB and ARG that may be still present in the treated wastewater. At the same time, coupling chemical oxidants with UV-C (i.e., UV AOP) would further enhance the means to simultaneously oxidize and degrade potentially harmful chemical contaminants.