<p> The forms of phosphorus in sediments of acid and non-acid shield lakes were determined in order to assess the effects of lake acidification on the mobility of sediment phosphorus. Sediment phosphorus is conveniently classified into three categories: non-apatite inorganic phosphorus (NAI-P), apatite-P and organic P. The distribution of P between different categories was found to be dependent on the lithology of the lake basin, the pH in the water column, and the redox conditions.</p> <p> More than 90% of inorganic P in shield lake sediments was in the NAI-P category, associated presumably with hydrated Fe and Al oxides. Organic P accounted for more than 40% of total P in sediments of acid lakes, which is proportionally higher than that found in sediments of neutral lakes. Bioavailable P, a measure of the fraction of sediment inorganic P readily available for biological utilization, amounted to ~70% of NAI-P, similar to that found in hard water lakes.</p> <p> A series of experiments was designed to investigate the immobilization of P from solution. The uptake of P by solid phase was explained by an adsorption mechanism. The quantitative estimates of phosphate sorption parameters for sediments of acid and non-acid lakes show that mineralogical and chemical characteristics of sediments are more important than the pH of water in determining their efficiency of P removal. Therefore, acidification of lakes does not significantly influence the uptake of P by sediments.</p> / Thesis / Master of Science (MSc)

This dissertation examines human mobility and population interactions at the Imperial Roman (ca. 1st–3rd c. CE) sites of Isola Sacra (SCR) at Portus, Velia in the Cilento of Italy, and Rue Jacques Brel Necropolis (JBR) in Saintes, France. Isotopes of oxygen (18Oc) and strontium (87Sr/86Sr) are used to assess instances of human mobility from the enamel of second molars (M2), providing a gauge of movement after age ~7–8 years. Nonmetric traits are employed in conjunction with isotopic perspectives to examine the nature of biological affinities and phenetic divergence between these three sites. Isotopic results of this study indicate that a significant number of individuals, including females and children, were mobile towards the sites at which they were ultimately interred, with the highest estimates of mobility provided by 18Oc seeing rates between 25%–38% across the three sites. 87Sr/86Sr results provided lower estimates of mobility ranging from zero cases at Velia to 30% at JBR, while combined 18Oc and 87Sr/86Sr analyses provided the lowest estimates of mobility ranging from zero cases at Velia to 20% at JBR. Such results suggest that a combined isotope approach may not necessarily increase the degree of mobility discrimination, bringing into question issues of regional homogeneity and overlap in 18Oc and 87Sr/86Sr values for the regions examined. A further examination of 18Oc variation in M1 vs. M2 vs. M3 for a sub-sample of 20 individuals indicates that childhood mobility was taking place at Portus. Nonmetric trait analysis provides insight to the nature of biological population similarity and divergence. Across the three sites SCR is the most similar to JBR and Velia, while Velia and JBR are the most dissimilar. The nature of these similarities suggests that overall the biological background of the people interred at JBR, SCR, and Velia is similar, but with unique regional phenetic differences indicating distinct biological populations at all three sites. Using these multiple lines of evidence this dissertation emphasizes a significant degree of mobility and population heterogeneity across the Roman landscape. It is evident from the research findings presented here that with the expanding Roman empire mobility and population interaction remained staples of Roman life. / Dissertation / Doctor of Philosophy (PhD)

In January 2019, Ghana launched its Year of Return program to mark 400 years since the arrival of the first enslaved Africans in Jamestown, Virginia. The year-long event was described as a spiritual birth right journey for members of the Black diaspora and aimed to boost tourism and migration to the country by posing Ghana as a key destination for the Black diaspora and African Americans in particular. As the Ghanaian state encourages the diaspora to travel and migrate to Ghana to help boost its economy, Ghanaian citizens are looking for opportunities to migrate out of Ghana for better education and employment opportunities. Considering this dichotomy, this thesis explores the differing and often contrasting mobilities apparent in the Black diaspora through the context of the Year of Return program. It is informed by fieldwork conducted via information and communication technologies (ICTs) over the COVID-19 pandemic through participant observation, interviews, and media analysis. This thesis first explores how Ghana's historical relationship with the Black diaspora laid the groundwork for the success of the Year of Return. It then explores how different understandings of Blackness were used by the Ghanaian state to promote connections across the Black diaspora. Finally, it focuses on the differing mobilities characterizing the phenomenon of return to Ghana to inquire into the state of global Black mobility.

With our global aging population, low muscular strength and function significantly impact an older adult’s capacity to remain independent. Older adults experience gradual declines in physical function and mobility leading to difficulty completing activities of daily living. These difficulties are conceptualized as an expression of mobility disability or through diagnoses of clinical geriatric syndromes such as frailty. Aging physiology in the musculoskeletal system clinically translates into declines in physical function due to losses in muscular strength. Preventative interventions may be appropriate as failing to intervene until critical thresholds are reached will increase healthcare expenditure. Resistance training is a highly beneficial, cost-effective, conservative strategy for community-dwelling older adults to optimize physical resiliency through increasing muscular strength and function lost due to aging, sedentary behaviour and/or physical inactivity. Resistance training needs to be dosed appropriately for function to improve, but clinicians rarely prescribe high-load resistance training with older adults, especially those at risk for mobility decline and frailty. The overarching goal of this thesis was to evaluate the role of resistance training in managing mobility disability and prefrailty. This thesis is comprised of three studies to address this goal: (1) The role of resistance training to improve or prevent mobility disability in community-dwelling older adults: a systematic review and meta-analysis. (2) The use of High- Intensity Enhanced Resistance Training (HEaRT) to optimize independence and quality of life in older adults with or at-risk of mobility disability: a pilot randomized controlled trial. (3) An Ounce of Prevention: a substudy of pre-frail older adults from the HEaRT pilot randomized controlled trial. / Thesis / Candidate in Philosophy / As people get older, the amount of muscle they have, and their strength start to decrease. When too much strength is lost, individuals can begin to have difficulties completing tasks around their home or can be at risk for developing health issues such as disability and frailty. Strength training has been one way proposed to increase strength and physical function for those at risk for mobility disability and those at risk for frailty (prefrailty). This strength training is often of low intensity despite guidelines advocating for higher-intensity exercise. This thesis evaluates the benefit of strength training, specifically using high-load, for those with mobility disability and the safety and feasibility of high-intensity resistance training for those with prefrailty and those at risk for or with established mobility disability.

Mobility models serve as the foundation for evaluating and designing airborne networks. Due to the significant impact of mobility models on the network performance, mobility models for airborne networks (ANs) must realistically capture the attributes of ANs. In this paper, I develop a comprehensive modeling framework for ANs. The work I have done is concluded as the following three parts. First, I perform a comprehensive and comparative analysis of AN mobility models and evaluate the models based on several metrics: 1) networking performance, 2) ability to capture the mobility attributes of ANs, 3) randomness levels and 4) associated applications. Second, I develop two 3D mobility models and realistic boundary models. The mobility models follow physical laws behind aircraft maneuvering and therefore capture the characteristics of aircraft trajectories. Third, I suggest an estimation procedure to extract parameters in one of the models that I developed from real flight test data. The good match between the estimated trajectories and real flight trajectories also validate the suitability of the model. The mobility models and the estimation procedure lead to the creation of “realistic” simulation and evaluation environment for airborne networks.

As mass analyzer technology has continued to improve over the last fifty years, the prospect of field-portable mass spectrometers has garnered interest from many research groups and organizations. Designing a field portable instrument entails more than the scaling down of current commercial systems. Additional considerations such as power consumption, vacuum requirements and ruggedization also play key roles. In this research, two avenues were pursued in the initial development of a portable system. First, micrometer-scale mass analyzers and other electrostatic components were fabricated using silicon on insulator-deep reactive ion etching, and tested. Second, the dimensions of an ion trap were scaled to the millimeter level and fabricated from common metals and commercially available vacuum plastics. This instrument was tested for use in ion isolation and collision induced dissociation for secondary mass spectrometry and confirmatory analyses of unknowns. In addition to portable instrumentation, miniature mass spectrometers show potential for usage in process and reaction monitoring. To this end, a commercial residual gas analyzer was used to monitor plasma deposition and cleaning inside of a chamber designed for laser ablation and soft landing-ion mobility to generate metal-main group clusters. This chamber was also equipped for multiple types of spectral analysis in order to identify and characterize the clusters. Finally, a portion of this research was dedicated to method development in sample collection and analysis for forensic study. A new method for the analysis of illicit chemistries collected via electrostatic lifting is presented. This method incorporates surface-enhanced Raman microscopy as a prescreening tool for nanoextraction and nanospray ionization mass spectrometry.

Indiana University-Purdue University Indianapolis (IUPUI) / The purpose of this study was to investigate the possibility of accomplishing simultaneous intrusion and distal root movement of monkey premolar teeth utilizing the molar teeth as anchorage. Four Macaque speciosa monkeys were used as the experimental specimens. Root springs of the type used in the segmented arch technique were used to apply unequal moments to the premolar and molar teeth. The root movement was accomplished by a couple generated by the unequal moments. The results were analyzed cephalometrically and histologically. It was found that it is possible to accomplish distal root movement and intrusion of the monkey premolars when the anchorage is restrained from eruption. When the anchorage is not restrained intrusion is minimal. Root resorption was found to be associated with the magnitude of the difference in the moments applied and the amount of tooth movement.

While studying at Virginia Tech in Blacksburg, I noticed a significant issue: the town lacked a central hub to unite people of all ages, including students, families, and the elderly. Blacksburg needed to transcend its reputation as solely a college town, and that became the main focus of my thesis. My goal was to explore effective ways of connecting people and boosting the town's economy. Drawing from my experience growing up in a European town, I realized that Blacksburg didn't have a dedicated space for its residents. The streets were dominated by vehicles, making it difficult for pedestrians to navigate. Main St., the busiest road in town, connected the south and north but was consistently congested, especially at night when students were out and about. To address this issue, I chose to intervene near the lively downtown area. Draper St., which runs parallel to Main St. and serves as the border between Blacksburg and Virginia Tech campus, seemed ideal. While Draper St. currently accommodated both vehicles and pedestrians, it didn't experience significant traffic. I decided to remove vehicular traffic from a four-block stretch, from College Avenue to Washington St. This section housed important landmarks like the Black House and the iconic Benny pizza place. The Farmer's Market, where locals sold fresh local produce twice a week, was also located here, along with popular social spots like Rivermill and Milk Parlor. To make space for new structures like a greenhouse, hotel, apartment complex, and retail spaces, I planned to eliminate some parking lots. The urban intervention would have only one intersection, where Draper St. meets Roanoke St., allowing for shared use by vehicles and pedestrians. This intersection would also serve as a drop-off point for Farmer's Market vendors. I firmly believe that this project has immense potential to benefit Blacksburg, not just financially but also by enriching its cultural fabric. / Master of Architecture / While at Grad school in Virginia Tech (Blacksburg, VA), I realized the lack of a connecting point between all the group ages including students, families and elderly people. Blacksburg should be more than a college town, and this is the main point of my thesis. How to connect people in a successful way as well as helping the town's economy. Based on my experience growing up in a European town, I realized there is no place in Blacksburg fully dedicated to people. All the streets share vehicular and pedestrian circulation. Main St. is the busiest in town, but it is also the principal axis connecting south and north Blacksburg. This road always has traffic, and it is not safe for pedestrians, especially at night when the students come out. This intervention should be close to downtown where activities take place. For this reason, I chose Draper St. which is directly parallel to Main St, acting as the borderline between Blacksburg and Virginia Tech campus. This street is currently design for cars and people, but it does not have a lot of traffic, so I decided to remove the vehicular circulation along 4 blocks, from College Avenue to Washington St. This portion has some important buildings such as the Black House, and the iconic Benny pizza place. There is also a very important location on this street, the Farmer Market where they sell fresh local products every Wednesday and Saturday. Rivermill and Milk Parlor are some popular social places on this street. There are some parking lots which I am getting rid of to add other structures like a green house, a hotel, an apartment complex and retail among others. This urban scale intervention will only have one intersection at Draper St. and Roanoke St. where cars will share road with pedestrians. This will also allow for a place to drop off the products for the Farmer Market. In my opinion this project will bring a lot of benefits to the town of Blacksburg, not only financially but also culturally.

Voting analysts in the United States have attempted to predict political orientation based on race, gender, occupation, educational achievement, and economic background. Yet, the substantial amount of research available on these factors has been directed toward the understanding of the white-majority vote. Now, as a result of the overwhelming growth of ethnic minority populations scholars are beginning to look at the potential decisive role of ethnic minority voters. Part of this newly formed voting bloc consists of Hispanics which are now one of the fastest and largest racial minority groups in the United States. This thesis aims to understand the Hispanic electorate by addressing their social mobility. Furthermore, this research will shed light into the socio-economic factors affecting the political affiliation of Hispanic voters.

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