Inference of Population History using Coalescent HMMs: Review and Outlook

Studying how diverse human populations are related is of historical and anthropological interest, in addition to providing a realistic null model for testing for signatures of natural selection or disease associations. Furthermore, understanding the demographic histories of other species is playing an increasingly important role in conservation genetics. A number of statistical methods have been developed to infer population demographic histories using whole-genome sequence data, with recent advances focusing on allowing for more flexible modeling choices, scaling to larger data sets, and increasing statistical power. Here we review coalescent hidden Markov models, a powerful class of population genetic inference methods that can effectively utilize linkage disequilibrium information. We highlight recent advances, give advice for practitioners, point out potential pitfalls, and present possible future research directions.Comment: 12 pages, 2 figure

Nested Multilevel Monte Carlo with Biased and Antithetic Sampling

We consider the problem of estimating a nested structure of two expectations taking the form $U_0 = E[\max\{U_1(Y), \pi(Y)\}]$, where $U_1(Y) = E[X\ |\ Y]$. Terms of this form arise in financial risk estimation and option pricing. When $U_1(Y)$ requires approximation, but exact samples of $X$ and $Y$ are available, an antithetic multilevel Monte Carlo (MLMC) approach has been well-studied in the literature. Under general conditions, the antithetic MLMC estimator obtains a root mean squared error $\varepsilon$ with order $\varepsilon^{-2}$ cost. If, additionally, $X$ and $Y$ require approximate sampling, careful balancing of the various aspects of approximation is required to avoid a significant computational burden. Under strong convergence criteria on approximations to $X$ and $Y$, randomised multilevel Monte Carlo techniques can be used to construct unbiased Monte Carlo estimates of $U_1$, which can be paired with an antithetic MLMC estimate of $U_0$ to recover order $\varepsilon^{-2}$ computational cost. In this work, we instead consider biased multilevel approximations of $U_1(Y)$, which require less strict assumptions on the approximate samples of $X$. Extensions to the method consider an approximate and antithetic sampling of $Y$. Analysis shows the resulting estimator has order $\varepsilon^{-2}$ asymptotic cost under the conditions required by randomised MLMC and order $\varepsilon^{-2}|\log\varepsilon|^3$ cost under more general assumptions.Comment: 28 pages, 2 figure

Hierarchical and adaptive methods for accurate and efficient risk estimation

Practical systems that depend on unknown factors are frequently well-represented through a stochastic model. By estimating statistics of the underlying model, critical features of the system can be inferred. When such inferences assist decision-making, accurate uncertainty quantification is crucial, meaning that robust error estimates or confidence intervals accompany the estimated parameters. Sufficiently accurate estimates can require several samples from the underlying model. When exact samples of the model are computationally infeasible or unavailable, one must carefully balance statistical errors with approximation bias to retain accurate uncertainty quantification. The multilevel Monte Carlo (MLMC) approach provides an efficient framework for accurately approximating expectations of quantities of interest given a hierarchy of increasingly accurate model approximations. Motivated by problems arising in financial credit risk management and option pricing, this thesis considers the development and analysis of novel MLMC estimators within two frameworks: Firstly, we develop a hierarchy of nested MLMC estimators to estimate systems of repeatedly nested expectations given approximate samples of the model conditioned an underlying filtration at a discrete progression of time points. Secondly, we consider an adaptive MLMC scheme to approximate point evaluations of the distribution of underlying quantities of interest. Both methods are combined to compute the probability of significant financial losses arising from credit risk factors. The method attains a specified error tolerance ε with an asymptotic cost of order ε −2 |log ε| 2 , reduced from order ε −5 using standard Monte Carlo estimationEngineering and Physical Sciences Research Council (EPSRC) Centre for Doctoral Training in Mathematical Modelling, Analysis and Computation (MAC-MIGS), grant EP/S02329/

TECHNOLOGY SOLUTIONS IN HEALTH CARE DELIVERY: THE COMPUTER-BASED PATIENT RECORD

The objective of this paper is to look at the benefits of the adoption of computer-based patient records and to formulate recommendations that assist in overcoming identified barriers to implementation. The benefits and barriers associated with the wide spread adoption of computer-based patient records systems in the North American marketplace are investigated. The clinical, workflow, administrative and revenue benefit of computer-based patient records are discussed in relation to the currently used paper-based system. Significant barriers to implementation are identified and recommendations as to how to overcome those barriers are presented. The business case for the adoption of computer-based patient records is made through the use of case studies of successful implementations and return on investment and payback period calculations

Tradition and Change: Two Buddhisms in the Bible Belt Sharing Common Ground Through Adaptation

This thesis examines how some American and Burmese forms of Buddhism in the Bible Belt today share common ground through a process of adaptation. Exploring tradition and change, I reveal how change often requires adaptation. Utilizing ethnographic research conducted in south central Kentucky and middle Tennessee, I argue that some Burmese and American forms of Buddhism in the Bible Belt experience change through three aspects of adaptation. These consist of reduction, syncretism, and preservation. I explore these three aspects through interviews and observations of immigrant Burmese Buddhist monks and American Buddhist meditation leaders. In doing so, I also examine the various ways in which the southern American landscapes affect change within traditional Burmese Buddhism through a process of Americanization. As a result of Theravada Buddhism’s relocation, change in Buddhism can also be seen in the American form, which is believed by many to becoming its own unique school of Buddhism. This can be found occurring in the regions of south central Kentucky and middle Tennessee. Preservation of tradition, an element of adaptation to Americanization, is a theme that frequently arose during my time spent at immigrant Burmese Buddhist temples and through interviews conducted with two ethnic Burmese Buddhist monks. The tendency to reduce Buddhism to a tradition of meditation was, on the other hand, a theme that came up in my conversations with two American meditation leaders. Their tendency to syncretize several schools of Buddhism is also explored. Being that the Buddhist subjects interviewed for this ethnography reside in the Bible Belt, their thoughts on Christianity and their interactions with Christians has also been included

Preserving the Narrative of 20th Century Art Song: A Guide for Instrumental Transcriptions of Vocal Music

Art song, by nature, is a combination of media: text and music. Composers map these two domains onto each other using established correspondences known as conceptual metaphors. The outcome, known as a conceptual blend, manifests a different cognitive perception than if the domains are experienced separately. The purpose of this dissertation is to keep these blends intact when performing instrumental transcriptions of vocal music. Without the ability to utter words, the performer must consider how they can bring life to the narratives through their instrument. A comprehensive set of performance practice guidelines are discussed, largely for practical application to the trumpet. Accompanying this dissertation are seventeen video recorded transcriptions of 20th century art song from German, French, and American composers, which implement a solution to be used along with these guidelines: subtitle translations. The addition of subtitles not only allows for the audience to experience the narratives in real-time with the music, but also creates an opportunity for instrumentalists to perform vocal repertoire that has yet to be explored in great depth. The expressive atonal and twelve-tone works of the Second Viennese School, experimental and Transcendental works of Charles Ives, deep Symbolist poetry set by Lili Boulanger, and evocative, text-driven works of Libby Larsen can be brought to life in compelling ways with their narratives intact

Restricted Quantum Theory of Affine Toda Solitons

We quantise the reduced theory obtained by substituting the soliton solutions of affine Toda theory into its symplectic form. The semi-classical S-matrix is found to involve the classical Euler dilogarithm.Comment: 10pp, LaTe

An Analysis of Federal Aviation Administration Enforcement Actions Against sUAS Operators

The Federal Aviation Administration (FAA) has promulgated regulations to govern the commercial operation of small uncrewed aircraft systems (sUAS). Compliance with these regulations is essential for maintaining safety in the National Airspace System. And if sUAS operators fail to comply with applicable federal aviation regulations, the FAA has been granted the authority to enforce these regulations. This study explores how the FAA has been exercising its enforcement power in the context of sUAS operator regulatory noncompliance. Using data obtained from a Freedom of Information Act request, this study examines 62 FAA enforcement actions levied against sUAS operators from 2012 until 2020. Key findings include trends in enforcement activity following the promulgation of Part 107 regulations; timelines associated with civil penalty and certificate action cases; and the specific regulations most frequently prosecuted by the FAA in sUAS enforcement cases

Separating the influence of projected changes in air temperature and wind on patterns of sea level change and ocean heat content

We present ocean model sensitivity experiments aimed at separating the influence of the projected changes in the “thermal” (near-surface air temperature) and “wind” (near-surface winds) forcing on the patterns of sea level and ocean heat content. In the North Atlantic, the distribution of sea level change is more due to the “thermal” forcing, whereas it is more due to the “wind” forcing in the North Pacific; in the Southern Ocean, the “thermal” and “wind” forcing have a comparable influence. In the ocean adjacent to Antarctica the “thermal” forcing leads to an inflow of warmer waters on the continental shelves, which is somewhat attenuated by the “wind” forcing. The structure of the vertically integrated heat uptake is set by different processes at low and high latitudes: at low latitudes it is dominated by the heat transport convergence, whereas at high latitudes it represents a small residual of changes in the surface flux and advection of heat. The structure of the horizontally integrated heat content tendency is set by the increase of downward heat flux by the mean circulation and comparable decrease of upward heat flux by the subgrid-scale processes; the upward eddy heat flux decreases and increases by almost the same magnitude in response to, respectively, the “thermal” and “wind” forcing. Regionally, the surface heat loss and deep convection weaken in the Labrador Sea, but intensify in the Greenland Sea in the region of sea ice retreat. The enhanced heat flux anomaly in the subpolar Atlantic is mainly caused by the “thermal” forcing