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No / Extracting waterborne contaminants to ozone-loaded Volasil¿245 (a siloxane solvent in which ozone is ten times more soluble than water) has been studied as a means of enhancing reaction kinetics and thus, providing more rapid wastewater decontamination. Investigation was carried out with respect to 2-chlorophenol and dichloromethane. Using a pilot scale continuous flow liquid¿liquid/ozone water treatment system, 2-chlorophenol was extracted to the ozone-loaded solvent phase and considerable extents of destruction were achieved. However, the approach was demonstrated to yield slightly less destruction than direct gas contact for the same utilization of ozone and enhanced reaction kinetics were not shown to occur. This was suggested to be due to increased interfacial mass transfer resistance and/or the promotion of less destructive reaction pathways. Modification of the existing pilot system, by conversion from co- to counter-current solvent-loading, enabled greater dissolved ozone concentrations to be achieved within the solvent. Increasing the counter-current exchange column height to not, vert, similar2.5 m was suggested for achieving a near optimum level of performance. The liquid¿liquid/ozone approach was demonstrated to be an effective means of indirectly exposing wastewater contaminants to concentrated ozone. As such the technology may be applicable as an alternative to direct gas contact in instances where the avoidance of contaminant sparging is desired (i.e. where contaminants are highly volatile, pungent and/or toxic) or foaming occurs

Groundwater plays a fundamental role in water resource sustainability in Virginia (USA), but overpumping has caused significant declines in the potentiometric surface in the Potomac Aquifer System (PAS). With water levels falling, communities are at risk of wells running dry, saltwater intrusion, and land subsidence. The Sustainable Water Initiative for Tomorrow (SWIFT) project is an aquifer long-term replenishment (ALTR) project that uses continuous recharge into the multi-layered confined aquifer system to restore the potentiometric surface over space and time and increase storage in the system. The SWIFT Research Center (SWIFT-RC) is a 1 million gallon per day (MGD) demonstration facility in Suffolk, Virginia that recharges the PAS through a multi-screen well. Addressing research questions about the impact of continuous, sustained recharge on aquifer systems is crucial to the long-term sustainability of an ALTR project. Quantifying how flow moves through the multi-layered system is necessary to communicate travel times and water quality impacts on the aquifer system. This work uses injectate as an intrinsic tracer, an in-situ flowmeter, and a bromide tracer test to evaluate how flow is distributed through the eleven screens in the recharge well and to assess how flow distribution changes over time. Typically, flow distribution in multi-screen wells is estimated only once over the length of a project and assumed to remain constant for modeling purposes; by measuring flow distribution using multiple methods over the course of the project, this work shows that flow distribution is not constant. In future ALTR projects, developing a consistent and robust monitoring plan to use injectate as an indicator of movement through the aquifer system, paired with other methods to monitor changes in flow distribution, will be a critical part of effectively evaluating how flow moves through the groundwater system. / Doctor of Philosophy / Groundwater plays a fundamental role in water resource sustainability in Virginia (USA), but overpumping has left the Potomac Aquifer System (PAS) depleted. With water levels falling, communities are at risk of wells running dry, adverse water quality changes, and even changes to the land surface due to subsurface settling. The Sustainable Water Initiative for Tomorrow (SWIFT) project is an aquifer long-term replenishment (ALTR) project that uses continuous recharge into the deep aquifer system to restore water levels and increase storage in the system. The SWIFT Research Center (SWIFT-RC) is a 1 million gallon per day (MGD) demonstration facility in Suffolk, Virginia that recharges the PAS through a multi-screen well. Addressing research questions about the impact of continuous, sustained recharge on aquifer systems is crucial to the long-term sustainability of an ALTR project. Quantifying how flow moves through the multi-layered system is necessary to communicate travel times and water quality impacts on the aquifer system. This work uses multiple methods to evaluate how flow is distributed through the eleven screens in the recharge well and to assess how flow distribution changes over time. Typically, flow distribution in multi-screen wells is estimated only once over the length of a project and is assumed to remain constant for modeling purposes; by measuring flow distribution using multiple methods over the course of the project, this work shows that flow distribution is not constant. In future ALTR projects, developing a consistent and robust monitoring plan to use recharge water itself as an indicator of movement through the aquifer system, paired with other methods to monitor changes in flow distribution, will be a critical part of effectively evaluating how flow moves through the groundwater system.

The Fermi Large Area Telescope has observed a gamma-ray excess toward the center of the Galaxy at ~ GeV energies. The spectrum and intensity of the excess are consistent with the annihilation of dark matter with a mass of ~100 GeV and a velocity-averaged cross section of ~ 1e-26 cubic centimeter per second. In the meantime, a population of unresolved millisecond pulsars (MSPs) in the Galactic center remains a possible source of the excess. Furthermore, recent analyses have shown that the excess prefers the spatial morphology of the stellar bulge distribution in the Galactic center, supporting a MSP origin. The new discovery makes it imperative to further study the signals from MSPs. This dissertation studies the gamma-ray emission from Galactic millisecond pulsars to provide new insights into the origin of the Galactic center excess. Using the GALPROP code, we simulate the propagation of e± injected by the putative MSPs in the Galactic bulge and calculate the inverse Compton (IC) emission caused by the e± losing energy in the interstellar radiation field. We find recognizable features in the spatial maps of the IC. Above TeV energies, the IC morphology tends to follow the distribution of the injected e±. Then, we study the Cherenkov Telescope Array (CTA) sensitivity to the IC signal from MSPs. We find that the CTA has the potential to robustly discover the IC signature when the MSP e± injection efficiencies are in the range ≈ 2.9-74.1%. The CTA can also discriminate between an MSP and a dark matter origin for the radiating e± based on their different spatial maps. Next, we analyze the Fermi data from directions of Galactic globular clusters. The globular clusters are thought to be shining in gamma rays because of the MSP population they host. By analyzing their gamma-ray spectra, we reveal evidence for an IC component in the high-energy tail of Fermi data. Based on the IC component in the globular cluster spectra, the e± injection efficiency of millisecond pulsars is estimated to be slightly smaller than 10%. Finally, we study the spatial morphology of the 511 keV signal toward the Galactic center using data from INTEGRAL/SPI. We confirm that the 511 keV signal also traces the old stellar population in the Galactic bulge, which is similar to the Fermi GeV excess. Using a 3D smoothing kernel, we find that the signal is smeared out over a characteristic length scale of 150 ± 50 pc. We show that positron propagation prior to annihilation can explain the overall phenomenology of the 511 keV signal. / Doctor of Philosophy / Dark matter means matter that does not interact with light; therefore, they are invisible to traditional observations. We know that dark matter exists based on plenty of gravitational evidence: the motions of stars in galaxies, the large-scale structure of the Universe, the temperature fluctuations in the cosmic microwave background. However, we still know very little about the particle nature of dark matter. Detecting dark matter is one of the most extensive missions of modern physics. In indirect detection, the dark matter particles are expected to annihilate or decay in the cosmos, producing messenger particles that include gamma rays, cosmic rays, and neutrinos. Astronomical observations could detect those signals and confirm the nature of dark matter. However, understanding the astrophysical sources is essential for indirect detection of dark matter as they may emit similar signals. For a recent example, the Fermi Large Area Telescope launched by NASA is the most sensitive gamma-ray telescope in the energy range of ~ 100 MeV to ~ 100 GeV. It has detected an excess of gamma-ray signals toward the Galactic center consistent with what we expect from dark matter annihilation. However, millisecond pulsars, a type of fast rotating neutron stars, may also generate similar gamma-ray signals. Therefore, the origin of the signal remains unsettled. In this dissertation, we study different prospective of the gamma-ray emission from the millisecond pulsars in the Milky Way. We first study the inverse Compton signal from the millisecond pulsars in the Galactic bulge, caused by the relativistic e± injected by the millisecond pulsars. We find that the signal traces the original distribution of the e± above TeV energies. Next generation ground-based gamma-ray observatories like the Cherenkov Telescope Array (CTA) could be used to detect the signal. We study the CTA sensitivity to such an inverse Compton signal. We find that CTA can detect the inverse Compton signal from millisecond pulsars and discriminate it from a dark matter signal. We also study the gamma-ray emission from globular clusters in the Milky Way. They are dense collections of old stars orbiting our Galaxy, and they are known for hosting many millisecond pulsars. We reveal evidence for inverse Compton emission from the gamma-ray data of globular clusters. Our discovery helps us better understand the high-energy property of millisecond pulsars. Last, we study the morphology of the Galactic 511 keV signal caused by positron annihilation. Compact objects including millisecond pulsars are potential sources of the positrons. We find that the old stellar distribution with a smearing scale of ~ 150 pc best describes the 511 keV signal. Positron propagation from their sources prior to annihilation could explain the measured smearing scale.

Parents teach their children about emotions through a process called emotion socialization and one way that they can do so is through shared discussions about emotions. Research in developmental psychology indicates that parental emotion socialization strategies through discourse such as elaboration and labels and explanations are related to children's emotion understanding and social competence. In the current study, I apply the concept of indirect communication, which has been used in linguistics since the 1970s, to parental emotion socialization with preschool-age children (n= 55; 31 females, 24 males). I define indirect communication as parental speech in which the form and function of a subject-verb phrase do not match and examined relations of parental indirect communication to the previously established strategies in developmental psychology of elaboration and use of labels and explanations. To understand whether this type of communication may influence children's development, I also examined relations of indirect communication to preschoolers' emotion understanding and social competence. Results indicate that parental indirect communication during positive events was related to parental explanations during negative events. Parental indirect communication did not significantly predict children's emotion understanding or social competence, but showed a trend for the association between indirect communication during negative event discussions and children's nonstereotypical emotion understanding. However, the direction for this association was opposite than hypothesized. These results do not suggest consistency of indirect communication across positive and negative event discussions as an emotion socialization strategy. / Master of Science

Numerous memory studies have demonstrated that epigenetic-mediated transcriptional regulation, such as post-translational histone modifications, is essential to memory formation and maintenance. Moreover, many studies on the mechanisms of memory have focused on fear memories underlying traumatic events, which helps to understand post-traumatic stress disorder (PTSD). However, these mainly focus on individuals directly experiencing the event, while different species have shown the ability to learn fear indirectly by observing a conspecific experiencing a trauma. Thus, our understanding of indirect fear learning (IFL)'s characteristics is very limited. The trimethylation of histone 3 lysine 4 (H3K4me3) is an essential regulator of active gene transcription in cells and has been shown to be critical for memory formation in the hippocampus, a major site of memory storage. However, it is unknown how H3K4me3 is coordinated to target genes during memory formation. Monoubiquitination of histone H2B (H2Bubi) is critical for recruiting H3K4me3 to DNA in a gene-specific manner during memory formation in the hippocampus. Furthermore, there is a great overlap between H3K4me3 and phosphorylation of histone H2A.X at serine 139 (H2A.XpS139), a marker to study DNA double-strand break (DSB) loci. DSB is a critical mechanism for solving DNA-related topological issues during transcription and replication, which could be triggered in some immediate early genes (IEGs) by neuronal activity, such as memory consolidation.Here, we used rat fear conditioning paradigms in combination with quantitative molecular assays, such as chromatin immunoprecipitation (ChIP), and gene editing techniques, like siRNAs and CRISPR-dCas9 manipulations, to study the role of hippocampal 1) H2Bubi and 2) DSBs in contextual fear memory consolidation and reconsolidation, respectively. Additionally, we behaviorally and molecularly characterized IFL and compared it to directly acquired fear subjects. We found that contextual fear conditioning changed the expression of 86 genes in the hippocampus one hour after training. Remarkably, siRNA knockdown of the H2Bubi ligase, Rnf20, abolished changes in all but one of these genes, Per1. Additionally, we report that the loss of Rnf20 in neurons, but not astrocytes, of the hippocampus impaired long-term memory formation. We next found an increase in H2A.XpS139 and H3K4me3 levels in the Npas4, an IEG important for contextual fear memory, promoter region 5 minutes after retrieval. In vivo siRNAmediated knockdown of the enzyme responsible for DSB, topoisomerase II β, prior to retrieval, decreased Npas4 promoter-specific H3K4me3 and H2A.XpS139 levels and impaired long-term memory. Lastly, our data show that both sexes can indirectly acquire fear from either sex using the auditory-cued IFL model. Moreover, our data show that molecular profiles in the amygdala are largely unique to direct or indirect fear learning and vary by sex. Collectively, this data reveals novel roles for histone phosphorylation and ubiquitination in regulating H3K4me3 and memory formation and shows behavioral and molecular differences in each sex based on the way they acquire fear. / Doctor of Philosophy / Changes in epigenetic mechanisms, processes that control the expression of genes without changing the original sequences, play a crucial role in the formation and maintenance of memory. Moreover, many studies on the mechanisms of memory have focused on fear memories underlying traumatic events, helping to understand post-traumatic stress disorder (PTSD). However, these majorly focus on individuals directly experiencing the event, while different species have shown the ability to learn fear indirectly by observing a conspecific experiencing a trauma. Thus, our understanding of indirect fear learning (IFL)'s characteristics is very limited. In the present study, we investigated some of these epigenetic mechanisms called histone modifications. In the brain, histone 3 lysine 4 trimethylation (H3K4me3), a histone modification, is critical for memory formation in the hippocampus, a key area for memory storage. However, it is still not fully understood how H3K4me3 is coordinated during memory formation. Another histone modification called H2B monoubiquitination (H2Bubi) helps recruit H3K4me3 to DNA and so is also crucial for memory formation. Here, using rat models, we found that the expression of 86 genes is changed during memory formation in the hippocampus and that this result is almost entirely dependent on the presence of H2Bubi. We also discovered that H2Bubi is critical for longterm memory formation only in neurons of the hippocampus, and not astrocytes (another type of brain cells). Additionally, there is a connection between H3K4me3 and the phosphorylation of histone H2A.X, another epigenetic mechanism that co-occurs with DNA breaks and may serve as a markerfor studying these breaks. DNA breaks play a vital role during gene expression and could be triggered by neuronal activity during memory formation. We observed an increase in H2A.X phosphorylation and H3K4me3 levels in a memory-permissive gene five minutes after memory retrieval. Inhibition of DSBs, prior to retrieval abolished these changes, and impaired long-term memory. This suggests a critical role for DSBs in memory maintenance and that H2A.X phosphorylation is necessary for the recruitment of H3K4me3 to DNA. Lastly, our data demonstrated that both males and females could learn fear indirectly from either sex by observing them undergoing auditory-cued fear conditioning. Additionally, we found distinct molecular patterns in the amygdala, a brain region involved in fear processing, depending on whether fear was directly or indirectly acquired, and it varied between sexes. Collectively, data from this dissertation reveals novel roles for histone modifications in memory formation and shows behavioral and molecular differences in each sex based on the way they acquire fear.

The fusion of voice and data applications, along with the demand for high data-rate applications such as video-on-demand, is making radio frequency (RF) spectrum an increasingly expensive commodity for current and future communications. Although bandwidth-efficient digital modulation alleviates part of the problem by requiring a minimal use of spectral resources, they put an extra design burden on RF engineers. RF transmitters and power amplifiers account for more than half the total maintenance cost of a base-station, while occupying nearly the same portion of space. Therefore, power amplifiers become a bottleneck for digital systems in terms of space and power consumption. However, power-efficient use of the amplifiers, although desirable, is extremely detrimental to end-to-end performance due to the very high peak-to-average power ratios of modulations that are used today. In order to reduce distortion while maintaining high power conversion efficiency in a power amplifier, linearization schemes are needed. In addition, significant frequency-dependent Memory Effects result in high power amplifiers operating on wideband signals. Therefore, these effects need to be considered during any attempt to minimize amplifier distortion. In this thesis, we present two schemes to cancel nonlinear distortion of a power amplifier, along with its memory effects and results for one of the schemes. The results highlight the fact that in the presence of significant memory effects, cancellation of these effects is necessary to achieve reasonable improvement in performance through linearization. We focus on predistortive schemes due to their digital- friendly structure and simple implementation. The operating environment consists of a multi-carrier W-CDMA signal. All of the studies are performed using numerical simulation on MATLAB and Agilent's Advanced Design System (ADS). / Master of Science

Through the investigation of indirect light, reflected color, and geometric construction, and by the awareness and understanding of what allows for experiences that engage the human emotion, this thesis offers a project which has the power and presence to move the soul. / Master of Architecture