Consolidation theory states that decreasing the spacing of prefabricated vertical drains will decrease the time required to achieve primary consolidation. Previous field tests have shown that there exists a "critical" drain spacing, which is the point at which further spacing decrease does not decrease the time of primary consolidation. This "critical" spacing is thought to be due to disturbance effects from installation of the drains. Previous studies have found that the "critical" drain spacing may be dependent upon soil layering and drain and mandrel dimensions. Thin, interbedded clay layers have been found to be affected greatly due to the smear zone, while few tests have been conducted to determine the validity for thick bedded clays. Currently two design and analysis methods are in existence, neither of which is standardized. The two methods are the modeling of the smear zone, which requires knowledge of soil parameters within that zone, and the modeling using a back-calculated Ch/Cv ratio.In order to evaluate the validity of these design methods and to obtain more data that can be used in determining the relationship between anchor type, drain spacing, and soil profile, full-scale field tests were conducted at Mountain View Corridor in Lehi, Utah. These field tests were performed along a test section that was divided into sections containing 5.8, 5.0, 4.0 and 3.0 ft triangular spacings and rebar or plate anchors. By using the smear zone model, with a Ch/Cv ratio of 1.25 and ds of 3.07 times dm, the time rate of settlement was able to be predicted reasonably well, while using the back-calculated Ch/Cv ratio, with no smear zone, also predicted the time rate reasonably well. From the testing, it was found that the thick clay profile can facilitate closer spacings than a thin clay profile. Also, it was found that the rebar anchor type causes about twice the disturbance of the plate anchor. The results helped validate the existing models and show that the effectiveness of the drains is dependent upon drain spacing, soil profile, and anchor type

While people sleep, the brain replays the same neural firings that resulted from waking activities that day. This results in greater memory strength following a sleeping delay than a waking delay. The current project built upon this fact in a series of three experiments. Experiment 1. Although previous research has demonstrated a benefit of sleep to memory strength, the literature has not established the impact of sleep on memory specificity. Computational models of medial temporal lobe function posit that discrimination and generalization across similar memories are accomplished through processes known as pattern separation and pattern completion, respectively. To discover whether sleep predisposes people toward pattern separation or pattern completion, participants studied pictures of common objects. After a 12-hour delay, during which participants either slept or stayed awake, participants indicated whether “lure” images were exactly the same or merely similar to those they studied. There was better memory discrimination in those who slept, consistent with a bias toward pattern separation following sleep. Experiment 2. In order to discover whether the pattern of memory demonstrated in Experiment 1 would carry over to semantic memories, participants studied textbook material and took a true/false test 12 hours later. There was a shift in the response trends following sleep, such that participants were more likely to mistakenly endorse highly similar false statements as “true” but were also more likely to correctly endorse more dissimilar false statements as “false.” However, we did not detect evidence of an increased bias toward pattern separation or pattern completion following sleep for this material. Our findings appear consistent with the prediction that memory specificity is benefitted by sleep. Experiment 3. Previous research has demonstrated that memories encoded later in the day are consolidated better than memories encoded earlier in the day. However, these studies have not controlled for the differential decay that memories suffer across these two elapsed periods. In this study, we attempted to show the degree of improvement afforded by sleep using a before-sleep comparison group. However, post hoc analyses revealed a significant interaction between the proposed outcomes and whether participants had napped during the day. These preliminary findings may suggest that napping differentially affects the consolidation of information studied before and after napping.

Both in practice and theory, the focus in architecture is often largely about growth. Architecture is, therefore, a tool that we largely use to accommodate growth. However, whilst many cities are experiencing growth, many are facing population decline. Latvia’s capital Riga is one example of this. So while architecture often fixates on growth, the discourse on decline does not normally involve architecture. With this project, I sought to investigate the question: ‘How can we use architecture as a tool to accommodate decline?’ Through the study of an empty site in Riga, in an area which has lost 60% of its resident population since 2000, the project envisages a building designed to slowly consolidate the functions of a shrinking city over an extended time span.  The proposal, a ‘House of Everything’ (Latvian: Viskautkā Māja) is developed in two main ways. First, through a strategy for the site, delineating the rules and parameters for the anticipated building and its functions. Second, with a detailed test, using the strategy to develop a completed building.

New heating techniques are required to better control heat transfer between heating tools and a composite towpreg in the automated fiber placement process. This dissertation suggests new heating techniques with liquid and rigid contact heat sources, and compares them with a widely used gas heat source for the fiber placement process. A thin towpreg composite model needs to be developed to describe the heat transfer. Subsequently, the response of the towpreg with each heat source was compared from manufacturing speed and energy efficiency viewpoints. The most promising heat source was developed for heat transfer modeling between a moving towpreg and dynamic heat source in the automated fiber placement. Through the heat transfer model, both the temperature controllability of the towpreg and manufacturing speed could be investigated. In addition, an accurate compaction process is needed in response to the growing demand for better composite processing. Since the errors in compaction mechanisms and robotic machinery in fiber placement have not been discussed in the literature, experimental investigation to address possible reasons for the variations in the compaction force was conducted with a compaction mechanism. A clearer understanding of the physical compaction process can lead to controllable process parameters for consistent ply compaction, such that the final parts quality can be enhanced. Even though this dissertation investigates the thin thermoset fiber placement process, the proposed approach could be universally applicable to other composite-fabrication processes. / Ph. D.

This dissertation describes the development and verification of a general purpose computer program, CONSOL97, for analysis of one dimensional consolidation of multi-layered soil profiles. The program uses an elasto-visco-plastic model that can simulate both consolidation and creep in a single consistent analysis. The finite element program uses standard oedometer test data to model stress-strain-time relationships, and the effect of strain rate on preconsolidation stress observed in the laboratory and in the field. Validation of the computer program by simulating standard oedometer tests is described and the applicability of the program in predicting field behavior is examined. The oedometer test simulations indicate good agreement with stress-strain and strain-log time test results during loading. Unloading behavior produces excessive rebound. Well-instrumented field tests at Väsby, Sweden, Skå-Edeby, Sweden and Berthierville, Canada indicate that elasto-visco-plastic CONSOL97 analyses produce better predictions of field behavior than conventional elasto-plastic models. CONSOL97 results were in good agreement for the Väsby and Berthierville test fills but underestimated displacements and pore pressures near the center of the normally consolidated clay layer beneath the Skå-Edeby test fill. / Ph. D.

This work is in the spirit of the literature on the understanding and analysis of the different forces that shape the takeover process. We focus on the strategic interaction among the raiders and we study their decision to enter the bidding for a target form in a context of asymmetric information. Each raider incurs a fixed takeover sunk. cost when she decides to enter the bidding. Therefore she wants to avoid bidding for the firm and losing the bid to a raider with a higher valuation. We analyze the Bayesian-Nash equilibrium in one-period, two-period and infinite period models where each raider decides whether and in which period to enter. This decision depends on the takeover cost, the target's reservation price and the distribution function of the raiders' valuations. We also consider the case where one of the raiders is a large shareholder and the role of management in maximizing the shareholders' interests. We find that raiders delay entry into the bidding when the takeover cost or the reservation price for the firm increase. Such an increase also implies a decrease in the probability of a takeover. If one of the raiders is a large shareholder, he will enter the bidding faster the bigger is the percentage of shares he owns in the target. The existence of a large shareholder will, however, discourage other raiders from entering. The shareholders of the target firm might benefit from an increase in the target's reservation price but they never profit from an increase in the takeover cost. We conclude with an empirical section that indirectly tests some of our model's implications. The results of our empirical work indicate that raiders enter the bidding faster when the management's reaction to the bid proves to be friendly. The premiums offered by the raiders and the size of the target test insignificant in determining the pre-bidding period. Finally we find that the existence of a large shareholder discourages other raiders from entry. However, the large shareholder has on average a longer pre-bidding waiting period than a raider with no ownership in the firm. / Ph. D.

Patients with Alzheimer’s disease (AD) experience sleep disturbances, including disruption in slow-wave sleep (SWS). Slow oscillations (≤1 Hz), a brain rhythm prevalent during SWS, play a role in memory consolidation. Interestingly, patients with AD exhibit slow oscillations of low amplitude, which might contribute to their memory impairments. The mechanisms underlying slow-wave disruptions in AD remain unknown. Slow oscillations originate in the neocortex. Cortical neurons from all layers oscillate between UP and DOWN states during slow oscillations. Astrocytes are known to support neuronal circuit functions, and disruptions in astrocyte activity might contribute to slow-wave aberrations. Here, we investigated astrocytic contributions to slow-wave disruptions in an animal model of beta-amyloidosis (APP mice). First, we monitored astrocytic calcium transients to determine whether astrocytic calcium dynamics were disrupted in APP mice. Fourier transform analysis revealed that the power, but not the frequency of astrocytic calcium transients, was disrupted in young APP mice. This suggested calcium dynamic of astrocytic network was altered and might contribute to the disruption of slow waves in APP mice. Second, we used optogenetics to synchronize cortical astrocyte activity at 0.6 Hz to drive slow oscillations in APP mice. Our results showed that optogenetic activation of ChR2-expressing astrocytes at the endogenous frequency of slow waves restored slow-wave power. Furthermore, chronic optogenetic stimulation of astrocytes at 0.6Hz for 14 or 28 days reduced amyloid plaque deposition, prevented calcium overload in neurites, and improved memory performance in APP mice. These results revealed a malfunction of the astrocytic network driving slow-wave disruptions, and suggested a novel target to restore slow-wave power in APP mice, with translational potential to treat AD.

Unlike other domains of cognition, the acquisition of procedural skills (e.g., the "how to" of memory) is spared by age. However, the consolidation (i.e., the transformation from labile memory to long-term storage) of this type of memory is compromised by age. Optimal memory consolidation for procedural skills is dependent on sleep. Sleep is also negatively impacted by normal, healthy aging. Recent research has identified the neural markers of the lost benefit of sleep for reduced memory consolidation with age. While this is relatively well-established for procedural memory, and for cognitively simple motor skills, the impact of age-related changes in sleep on cognitively complex procedural memory consolidation (i.e., novel cognitive strategies required for "problem-solving skills") remains to be investigated. Furthermore, reduced capacity to solve problems with age has serious mental health-related consequences, including increased depression and suicide attempts, as well as disability in depressed, cognitively impaired older adults. Moreover, problem-solving therapy has been found to improve quality of life in older adults. As such, the aims of these series of studies were to investigate: 1) the behavioural consequences of age on sleep-dependent memory consolidation, 2) identify the electrophysiological markers during sleep of the lost benefit of sleep, 3) identify the age-related changes in brain structure and how this relates to and behavioural outcomes and sleep, and, 4) identify the impact of age on sleep-dependent consolidation of the memory trace for problem-solving skills. Using an innovative combination of EEG, MRI, and behavioural testing in healthy young and older adults, these series of studies revealed novel insights into the breakdown of the normal processes that occur during sleep that support memory. The main objective of this thesis is to identify the neural markers of the very earliest signs under optimal conditions of age-related cognitive decline for problem-solving skills. Investigating the neurophysiological and behavioral consequences of age-related changes in sleep, and their impact on problem-solving skills, will help reveal therapeutic targets for future research that will improve quality of life for seniors. Furthermore, this research will ultimately lead to the development of early interventions targeting sleep that could delay or lessen the severity of the onset of clinically significant cognitive impairment; as those who sleep better, may also age better cognitively.

The wet method of deep mixing constructs binder-treated soil columns by mixing a binder-water slurry with soft soil in-situ to improve the engineering properties of the soil. The strength of binder-treated soil is affected by characteristics of the in-situ soil and binder, mixing conditions, and curing conditions.The study presented herein aims to investigate the influences of curing time, curing temperature, mix design proportion, organic matter in the soil, and curing stress on the strength of cement-treated soil. Fabricated and natural soft soils were mixed with a cement-water slurry to mimic soil improved by the wet method of deep mixing. Laboratory-size samples were cured under various curing conditions and tested for unconfined compressive strength (UCS).The experimental test results showed that (1) a higher curing temperature and longer curing time generally increase the strength; (2) organic matter in cement-treated soil decrease and/or delay the strength development; and (3) curing stress affects the strength but its effect is influenced by drainage conditions. Based on the test results, strength-predicting correlations for cement-treated soil that account for various curing conditions and organic contents were proposed and validated.This research contributes to advancing the knowledge about the effects of strength-controlling factors of soil improved by cement and to improving the reliability of strength predictions with the proposed correlations. Therefore, the number of sample batches that need to be prepared and tested in a deep mixing project can be reduced, thereby saving the project's time and costs while achieving the target strength of the improved soil. / Doctor of Philosophy / The deep mixing method has gained popularity in the U.S. as a ground improvement technique since the late 1990s. This method involves blending the native soil that needs to be improved with a binder such as cement and/or lime. Two types of deep mixing methods are available, depending on how to add binder to the soil: the wet method injects a binder-water slurry, while the dry method uses a powder form of binder.The binder reacts with water and soil thereby enhancing the engineering properties of the soil. The strength of binder-treated soil is influenced by many factors: (1) characteristics of native soil and binder; (2) mixing conditions (e.g., the amount of binder added and mixing energy); and (3) curing conditions (e.g., curing time, temperature, and stress). In this dissertation, the effects of curing conditions and organic matter in the soil on the strength of cement-treated soil were investigated. Fabricated and natural soils were mixed with cement-water slurry to simulate the wet method, and the prepared samples were cured under various conditions. The strength results of cured samples showed that the characteristics of cement-treated soil are significantly affected by the amount of cement in the mixture, curing time, curing temperature, organic matter in soil, and curing stress. The test results were also used to derive correlations that account for the influences of curing conditions and organic matter.The findings and strength-predicting correlations presented in this research are expected to improve the knowledge about the deep mixing method and the reliability of strength prediction in a deep mixing project. This research, eventually, contributes to reducing time and cost of the project.

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