VictorJuiz/thesis huggingface dataset:
Finite Rank Perturbations of Random Matrices and their Continuum Limits

We study Gaussian sample covariance matrices with population covariance a bounded-rank perturbation of the identity, as well as Wigner matrices with bounded-rank additive perturbations. The top eigenvalues are known to exhibit a phase transition in the large size limit: with weak perturbations they follow Tracy-Widom statistics as in the unperturbed case, while above a threshold there are outliers with independent Gaussian fluctuations. Baik, Ben Arous and Péché (2005) described the transition in the complex case and conjectured a similar picture in the real case, the latter of most relevance to high-dimensional data analysis. Resolving the conjecture, we prove that in all cases the top eigenvalues have a limit near the phase transition. Our starting point is the work of Rámirez, Rider and Virág (2006) on the general beta random matrix soft edge. For rank one perturbations, a modified tridiagonal form converges to the known random Schrödinger operator on the half-line but with a boundary condition that depends on the perturbation. For general finite-rank perturbations we develop a new band form; it converges to a limiting operator with matrix-valued potential. The low-lying eigenvalues describe the limit, jointly as the perturbation varies in a fixed subspace. Their laws are also characterized in terms of a diffusion related to Dyson's Brownian motion and in terms of a linear parabolic PDE. We offer a related heuristic for the supercritical behaviour and rigorously treat the supercritical asymptotics of the ground state of the limiting operator. In a further development, we use the PDE to make the first explicit connection between a general beta characterization and the celebrated Painlevé representations of Tracy and Widom (1993, 1996). In particular, for beta = 2,4 we give novel proofs of the latter. Finally, we report briefly on evidence suggesting that the PDE provides a stable, even efficient method for numerical evaluation of the Tracy-Widom distributions, their general beta analogues and the deformations discussed and introduced here. This thesis is based in part on work to be published jointly with Bálint Virág.

Keywords: random matrices
spiked model
Tracy-Widom laws
BBP phase transition
stochastic Airy operator
Painlevé equations
sample covariance matrices
Wishart matrices
Advisor: Virág, Bálint
Transitivité et marquage d'objet différentiel

This thesis deals with direct object nouns case-marked differentially. According to the commonly assumed generalization nouns marked with ACC case are prototypical objects representing high transitivity, whereas nouns marked with non-accusative cases are not. However, such a view ignores the possibility of a much finer distinction and fails to account for empirical data from languages with rich case morphology, such as Ukrainian. Given the complexity of the phenomenon under study the main objective of our investigation is to account exhaustively for all possible instances of non-accusative case marking and case alternations on direct objects in Ukrainian trying to classify and analyze the data by specifying the factors that condition the distinction ‘accusative versus non-accusative case marking’ and by integrating the phenomenon of differential object marking (DOM) into a formal model. We present DOM as a phenomenon that, together with the phenomenon of unaccusativity, can be subsumed under a broader concept of non-accusativity (defined as inability of verbs to assign ACC case). In this context we show that in Ukrainian and French morphosyntactic case realization has semantic underpinnings and that issues related to case valuation emanate from the intersection of different phenomena – DOM and nominal incorporation, DOM and verb typology, DOM and the process of (de)transitivization, and so on. However, the (morphosyntactic) visibility of those points of intersection varies from one language to another. Generativist distinction between syntactic (abstract) and morphological cases as well as the functionalist idea that case markings can be characterized as morphemes having different functional applications constitute the basis of our analysis of data. Using the typological views of these two approaches on the category of case as guidelines in our classification of collected data, we resort to minimalist formalism. Case is treated as an uninterpretable feature and a clear distinction is drawn between two types of case valuation – case checking and case assignment. Structural cases are checked during verb-raising and inherent (lexical) cases (among which we find predicate and default cases) are assigned either by a weak (or defective) v or by (an overt or null) preposition (P) in situ.

Keywords: transitivity relation, Universal Transitivity Template, direct object marking, Ukrainian language,
rich case morphology, non-accusative case marking, case alternations, semantic feature realization
Advisor: Roberge, Yves
Processing Desktop Work on a Large High-resolution Display: Studies and Designs

With the ever increasing amount of digital information, information workers desire more screen real estate to process their daily desktop work. Thanks to the quick advance in display technology, big screens are increasingly affordable and have been gradually adopted in desktop computing environments. A large wall-size high resolution display, a recent emerging class of display which possesses a huge visualization surface, could potentially benefit information processing work. In this dissertation we investigate such a large display as the primary working space for information processing work. We firstly conducted a longitudinal diary study and three control experiments investigating effects of a large display on information processing work. The longitudinal diary study investigates large display use in a personal desktop computing context by comparing it with single- and dual-monitor. The three controlled experiments further investigate the effects of two factors determining resolution of a display—physical size and pixel-density on users’ performance and behaviors. The diary study reveals the distinct behavior patterns of large display users in partitioning screen space and managing windows, while the control experiments deeply reveal the effects of the physical size and pixel density of a display on different information processing tasks. Aside from studying a continuous large display, we also articulate how interior bezels within a tiled-monitor large display affect users’ performance and behaviors in basic visual search and action tasks via a series of controlled experiments. Based on the understanding of large display effects and users’ behavior patterns, we then design new interaction techniques to address a big challenge of working on a large display: managing overflowing windows. We design and implement a large display oriented window management system prototype: WallTop. It includes a set of interaction techniques that provide greater flexibility for managing windows. Usability tests show that users can quickly and easily learn the new techniques and apply them to realistic window management tasks with increased efficiency on a large display.

Keywords: Large Display
Window Management
Desktop Work
Advisor: Balakrishnan, Ravin
The Web of Care: A Multi-method Study Examining the Role of Online Communities as a Source of Peer-to-peer Supportive Care for Breast Cancer Survivors

This dissertation uses a multi-method approach to examine the role of online communities as a source of peer-to-peer supportive care for breast cancer survivors. A collection of four studies is presented. Study 1) A systematic search of the Internet identified 111 active online communities for breast cancer survivors with extensive archives of personal health experiences (one third had over 100,000 posts each as of 2010-10-26). More than one-third (36.0%) were initiated by breast cancer survivors or loved ones, and more than two-thirds (69.5%) were maintained with little or no professional input. Study 2) An analysis of Facebook (www.Facebook.com) identified 620 public breast cancer groups containing a total of 1,090,397 members as of 2008-11-23. The majority of groups were created for fundraising and awareness purposes (92.6%), rather than supportive care (7.4%). Study 3) One hundred breast cancer survivors, known to provide peer support were surveyed on their supportive care needs and use of online communities. Two-thirds (68.6%) of the 73 respondents reported at least one unmet need, most frequently (30 to 40%) concerning sexual problems, stress, survivor identity, fear of recurrence, and ongoing symptoms or side effects. About one-third (31.5%) used online communities predominantly during and while recovering from treatment. Reasons for non-use included lack of need, self-efficacy, trust and awareness. Study 4) Twelve breast cancer survivors who participated in the previous study were interviewed on how and why they used online communities. Unmet needs drove use, particularly during periods of stress, uncertainty or insufficient local support. Online communities served as a unique supportive care resource due to their quality of information, reassurance from similar others, availability, anonymity, and limited commitment. Social support, technology adoption and health behaviour theories help to explain use. Online communities have the potential to fill gaps in health care services by addressing the supportive care needs of breast cancer survivors in a way that may not be available elsewhere, and survivors may play an increasingly important role as care providers. Future research must focus on overcoming barriers to use, and identifying factors that enhance their effectiveness among diverse groups.

Keywords: breast cancer
supportive care
Internet
social media
peer support
health behaviour
Advisor: Jadad, Alejandro R.
Free Energy Landscape of Protein-like Chains Interacting under Discontinuous Potentials

The free energy landscape of a protein-like chain is constructed from exhaustive simulation studies using a combination of discontinuous molecular dynamics and parallel tempering methods. The protein model is a repeating sequence of four kinds of monomers, in which hydrogen bond attraction, electrostatic repulsion, and covalent bond vibrations are modeled by step, shoulder and square-well potentials, respectively. These protein-like chains exhibit a helical structure in their folded states. The model allows a natural definition of a configuration by considering which beads are bonded. In the absence of a solvent, the relative free energy of dominant structures is determined from the relative populations, and the probabilities predicted from the calculated free energies are found to be in excellent agreement with the observed probabilities at different temperatures. The free energy landscape of the protein-like chain is analyzed and confirmed to have funnel-like characteristics, confirmed by the fact that the probability of observing the most common configuration approaches unity at low enough temperatures for chains with fewer than 30 beads. The effect on the free energy landscape of an explicit square-well solvent, where the beads that can form intra-chain bonds can also form (weaker) bonds with solvent molecules while other beads are insoluble, is also examined. Simulations for chains of 15, 20 and 25 beads show that at low temperatures, the most likely structures are collapsed helical structures. The temperature at which collapsed helical structures become dominant is higher than in the absence of a solvent. Finally, the dynamics of the protein-like chain immersed in an implicit hard sphere solvent is studied using a simple model in which the implicit solvent interacts on a fast time scale with the chain beads and provides sufficient friction so that the motion of monomers is governed by the Smoluchowski equation. Using a Markovian model of the kinetics of transitions between conformations, the equilibration process from an ensemble of initially extended configurations to mainly folded configurations is investigated at low effective temperatures for a number of different chain lengths. It was observed that folding profiles appear to be single exponentials and independent of temperature at low temperatures.

Keywords: Protein Folding
Parallel Tempering
Free Energy Landscape
Hybrid Monte Carlo
Advisor: Schofield, Jeremy
The Impact of Non-thermal Processes in the Intracluster Medium on Cosmological Cluster Observables

In this thesis we describe the generation and analysis of hydrodynamical simulations of galaxy clusters and their intracluster medium (ICM), using large cosmological boxes to generate large samples, in conjunction with individual cluster computations. The main focus is the exploration of the non-thermal processes in the ICM and the effect they have on the interpretation of observations used for cosmological constraints. We provide an introduction to the cosmological structure formation framework for our computations and an overview of the numerical simulations and observations of galaxy clusters. We explore the cluster magnetic field observables through radio relics, extended entities in the ICM characterized by their of diffuse radio emission. We show that statistical quantities such as radio relic luminosity functions and rotation measure power spectra are sensitive to magnetic field models. The spectral index of the radio relic emission provides information on structure formation shocks, {\it e.g.}, on their Mach number. We develop a coarse grained stochastic model of active galaxy nucleus (AGN) feedback in clusters and show the impact of such inhomogeneous feedback on the thermal pressure profile. We explore variations in the pressure profile as a function of cluster mass, redshift, and radius and provide a constrained fitting function for this profile. We measure the degree of the non-thermal pressure in the gas from internal cluster bulk motions and show it has an impact on the slope and scatter of the Sunyaev-Zel'dovich (SZ) scaling relation. We also find that the gross shape of the ICM, as characterized by scaled moment of inertia tensors, affects the SZ scaling relation. We demonstrate that the shape and the amplitude of the SZ angular power spectrum is sensitive to AGN feedback, and this affects the cosmological parameters determined from high resolution ACT and SPT cosmic microwave background data. We compare analytic, semi-analytic, and simulation-based methods for calculating the SZ power spectrum, and characterize their differences. All the methods must rely, one way or another, on high resolution large-scale hydrodynamical simulations with varying assumptions for modelling the gas of the sort presented here. We show how our results can be used to interpret the latest ACT and SPT power spectrum results. We provide an outlook for the future, describing follow-up work we are undertaking to further advance the theory of cluster science.

Keywords: Cosmology
Large-scale Structure
Galaxy Clusters
Numerical
Theory
Advisor: Bond, J. Richard
Music for Solo Trumpet and Electronics: A Repertoire Study

This dissertation examines the repertoire for solo trumpet and electronics through a study of the genre as a whole and discussions of four compositions that represent its main stylistic approaches. An obscure but fascinating genre, current research in this area is limited to discussions of a few of its compositions in other dissertations and lecture recitals. By investigating this music, this dissertation will contribute to an area that has so far seen little research while promoting new repertoire that greatly expands the musical possibilities of solo trumpet performance. Based on the List of Compositions for Solo Trumpet and Electronics compiled by the author, several aspects of this repertoire are described in Chapter Two, including its development from 1965 to 2009 and the relative popularity of its different compositional approaches. The primarily academic background of this repertoire’s composers is discussed as well as the diverse nationalities they represent. The relative obscurity of this repertoire is suggested by the number of compositions for solo trumpet and electronics that have been published and recorded. A discussion of the aesthetic, qualitative and practical aspects of the repertoire is presented in Chapter Three. Based on interviews with leading performers of this repertoire and the composers of the pieces examined in this dissertation, this music is discussed from the perspective of musicians who have significant experience in this field. Their interviews illuminate several important issues that may not be apparent to musicians who are unfamiliar with this repertoire. Chapters Four through Seven discuss four representative compositions from the List. An overview of each piece is given, along with biographical information about its composer, a description of its electronic components, discussion of relevant performance techniques, and formal analysis of the composition. Conclusions based on this investigation and suggestions for future research are suggested in Chapter Eight.

Keywords: Trumpet
Electronics
Tape
Live Electronics
Advisor: Reynolds, Jeffrey
A Role for MEF2 in the Synaptic Plasticity Mechanisms Underlying Long-term Memory Formation

The synaptic remodeling of neural circuits is thought to underly memory formation. Both long-term memory formation and remote memory formation are thought to involve a process restructuring of synapses in specific areas of the brain. The transcription factor myocyte enhancer factor 2 (MEF2) has been shown to restrict spine growth in both in vivo and in vitro. It has been suggested that MEF2 is a critical molecule involved in memory formation, however, MEF2‘s role in adult memory formation it is largely unexplored. Thus, we have sought to characterize MEF2’s involvement in the formation of long-term and remote memory formation. We first showed that acute overexpression of MEF2 in the hippocampus blocks long-term spatial memory formation and activity-dependent spine formation. We next found that acute overexpression of MEF2 in the lateral amygdala likewise blocks long-term fear memory formation, suggesting that MEF2 is critical protein involved in synaptic plasticity necessary for long-term memory formation. We next demonstrated the bi-directionality of MEF2 by decreasing MEF2 function in the hippocampus and amygdala and showing a facilitation in memory formation. Together, these results suggest that MEF2 is a critical protein, which regulates spine formation important for the formation of long-term memories. We next investigated whether similar synaptic plasticity mechanisms are involved in the systems consolidation. We acutely overexpressed MEF2 in the anterior cingulate cortex at different time points following contextual fear conditioning. We noted that there was a critical window, where MEF2 blocks spine density increases in the ACC and remote memory formation. Results from this study, suggest that cortical synapses undergo a process of strengthening and remodeling and that MEF2 is a critical regulator involved. Our results demonstrate that MEF2 is involved in the synaptic consolidation of long-term and remote memories.

Keywords: Memory
Synapse
MEF2
Behaviour
Advisor: Josselyn, Sheena
Storage Practices, Intensive Agriculture, and Social Change in Mumun Pottery Period Korea, 2903–2450 Calibrated Years B.P.

Storage is an important part of the background in many archaeological studies of the origins of early complex societies. Yet, a problem with many of these studies of formation and change in complex societies is that the social significance of storage is assumed rather than demonstrated. In this dissertation, I examine the practice of storage in three regions of prehistoric Korea and its relationship with socio-political structural changes. I analyze the distribution of storage artifacts and features such as pits, large-capacity pottery, and raised-floor structures in the context of their spatial relationships with other archaeological features and elite precincts at the household and settlement levels. The archaeological features used for storage in the Mumun Pottery Period (3390-2290 calibrated years B.P.) changed in form diachronically and show that underground pit storage remained constant during the period of study and that clandestine storage was not completely replaced by above-ground visible storage. Elite actors seem to have had some influence on the nature of storage in at least two central settlements, Daepyeong I and II and Songguk-ri, but appear to have been unable to completely control stored agricultural surplus in the two settlements and had little control over the surrounding areas.

Keywords: archaeology
storage strategies
Korea
settlements
households
socio-political complexity
East Asia
Mumun Pottery Period
Advisor: Crawford, Gary
The Light Verb Construction in Korean

Light verb constructions have been treated as a relevant linguistic topic because they show unique characteristics that are not found in other verb constructions in Korean. Thus, previous studies are mainly focused on specific characteristics: (i) the relationship between light verbs and v and (ii) the affixation of accusative case particles. However, in this thesis, I examine more important issues related to light verb constructions in Korean: (i) how light verb constructions can works as predicates in clauses, (ii) the nature of the relationship between the complement and the light verb in light verb constructions, and (iii) where the complement and the light verb are present in the surface structure in Korean. Operating under the assumption that the light verb construction is a way of presenting a predicative type similar to lexical verbs or adjectives in Korean, I claim that (i) the lexical-semantic and syntactic information of all predicates, including light verb constructions, is determined in the “lexical conceptual structure” (e.g., Levin & Rappaport 1998), (ii) the conceptual categories in the lexical conceptual structure become the lexical items in the lexicon differently in light verb constructions than in lexical verb constructions, and (iii) the light verb construction is built by incorporation which is similar to semantic noun incorporation (e.g., Dayal 2010). In addition, in this thesis I will present new characteristics of light verb constructions in Korean: (i) the function of each component in the light verb construction such as the modifier and the modified item, (ii) the relationship between components in the light verb construction (i.e., s-selection), (iii) the existence of a functional projection between two components (i.e., Event Phrase), and (iv) the generation of the negation particle an ‘not’ under the head of vP.

Keywords: light verb construction
Korean
Advisor: Massam, Diane