Solar neutrino physics at dark matter direct detection experiments

As the sensitivity of direct detection experiments improves, they will soon be subject to a new, irreducible background from the coherent elastic scattering of solar neutrinos with nuclei. The presence of new physics can modify this scattering rate, and signals of neutrino scattering may appear in direct detection experiments sooner than expected. In this thesis, we explore the effects of several simplified models of new physics on neutrino scattering at direct detection experiments. We introduce the neutrino contour, a projection of the modified coherent neutrino scattering rate on a dark matter parameter space. This contour can be used to quickly identify whether a direct detection experiment could set competitive constraints on a given model, or conversely, whether the model could produce a large enough neutrino scattering rate to hinder searches for dark matter at that experiment. We discuss the subtleties that arise while computing constraints from the results of one experiment, CDMSlite, in particular the challenges of including electron scattering in the analysis. Finally, we calculate the sensitivity of several future direct detection experiments to one model, the \umt. We find that the upcoming LUX-ZEPLIN experiment will be able to test solutions to two ongoing problems in fundamental physics: the muon g-2 anomaly and the $H_0$ tension

Early Identification of Students at Risk for High School Dropout

For years, many have hoped to identify why high school students drop out. Typically, studies focus on factors identified in high school or middle school. By tracking a cohort of North Carolina students from third grade onward, we attempt to identify areas for intervention even earlier in order to prevent dropouts. Indeed, we find that variables that can be viewed as indicators of high risk for drop out in middle school are already measurably present as early as third grade. This suggests interventions can begin when students are still very young and when treatment is likely to be more effective.Honors thesi

The detrimental effects of emotional process dysregulation on decision-making in substance dependence

Substance dependence is complex and multifactorial, with many distinct pathways involved in both the development and subsequent maintenance of addictive behaviors. Various cognitive mechanisms have been implicated, including impulsivity, compulsivity, and impaired decision-making. These mechanisms are modulated by emotional processes, resulting in increased likelihood of initial drug use, sustained substance dependence, and increased relapse during periods of abstinence. Emotional traits, such as sensation-seeking, are risk factors for substance use, and chronic drug use can result in further emotional dysregulation via effects on reward, motivation, and stress systems. We will explore theories of hyper and hypo sensitivity of the brain reward systems that may underpin motivational abnormalities and anhedonia. Disturbances in these systems contribute to the biasing of emotional processing toward cues related to drug use at the expense of natural rewards, which serves to maintain addictive behavior, via enhanced drug craving. We will additionally focus on the sensitization of the brain stress systems that result in negative affect states that continue into protracted abstinence that is may lead to compulsive drug-taking. We will explore how these emotional dysregulations impact upon decision-making controlled by goal-directed and habitual action selections systems, and, in combination with a failure of prefrontal inhibitory control, mediate maladaptive decision-making observed in substance dependent individuals such that they continue drug use in spite of negative consequences. An understanding of the emotional impacts on cognition in substance dependent individuals may guide the development of more effective therapeutic interventions

Case Report: The Complexities of Managing Medications and the Importance of Deprescribing Anticholinergics in Older Adults

Potentially inappropriate anticholinergic medications (including over-the-counter products), polypharmacy, and the existence of communication barriers among members of the interprofessional team frequently contribute to clinical complexity in older adults. We present the case of a frail 86-year old female from the perspective of a community pharmacist managing outpatient medications and transitions of care. CD’s past medical history is significant for dementia, multiple falls, recurrent urinary tract infections, depression, cardiac arrhythmia, macular degeneration, chronic pain, depression, and cerebrovascular disease

A Quarter Century Exploring Tetrahymena *

In reviewing 25 years of work on Tetrahymena , the author describes early difficulties experienced by himself and others in developing a chemically-defined medium and in defining the taxonomy of T. pyriformis. With identification of its essential requirements, a variety of nutritional studies revealed the close resemblance between the metabolic pathways of this ciliate and those of the chick and rat. This suggested studies on the effects of gamma radiation and the effect of antibiotics. Attention then turned to the puzzle of the absence of conjugation in all strains of T. pyriformis then maintained in laboratories. The observation that these strains were all amicronucleate led to the discovery of mating types (with D. F. Gruchy). This brought up the problem of what constitutes a species and how it might be solved in T. pyriformis where clearly defined groups are set off from other similar groups (varieties) by a breeding barrier. Another problem is whether a life cycle exists in this ciliate and if so, the role amicronucleate strains play in this cycle. The origin and obvious evolutionary success of these “genetically dead” strains are other problems that are considered. The search for nutritional markers for genetic experiments inspired large-scale collections, including some from tropical habitats. Strains were found which differed in serine and pyridoxine requirements. Genetic analysis was hindered by the high lethality following conjugation, unsatisfactory mating behavior in some clones, and the complete absence of autogamy, the latter making it difficult to obtain homozygous clones. The use of x-radiation yielded haploid individuals; when these were mated with diploid clones the resulting haploid progeny proved that the genes controlling mating type and pyridoxine synthesis resided in the micronucleus. Genetic analysis of the serine and pyridoxine mutants supports the idea that T. pyriformis is more of an outbreeder than an inbreeder. Left for the future is an extension of our knowledge of the breeding system of T. pyriformis and ultimately to examine critically the factors responsible for the success of this ubiquitous ciliate.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71977/1/j.1550-7408.1959.tb03918.x.pd

Error of truncated Chebyshev series and other near minimax polynomial approximations

AbstractIt is well known that a near minimax polynomial approximation p is obtained by truncating the Chebyshev series of a function ƒ; after n + 1 terms. It is shown that if ƒ; ϵ C(n + 1)[−1, 1], then ∥ƒ; − p ∥ may be expressed in terms of ƒ;(n + 1) in the same manner as the error of minimax approximation. The result is extended to other types of near minimax approximation

Bubbles and Filaments: Stirring a Cahn-Hilliard Fluid

The advective Cahn-Hilliard equation describes the competing processes of stirring and separation in a two-phase fluid. Intuition suggests that bubbles will form on a certain scale, and previous studies of Cahn-Hilliard dynamics seem to suggest the presence of one dominant length scale. However, the Cahn-Hilliard phase-separation mechanism contains a hyperdiffusion term and we show that, by stirring the mixture at a sufficiently large amplitude, we excite the diffusion and overwhelm the segregation to create a homogeneous liquid. At intermediate amplitudes we see regions of bubbles coexisting with regions of hyperdiffusive filaments. Thus, the problem possesses two dominant length scales, associated with the bubbles and filaments. For simplicity, we use use a chaotic flow that mimics turbulent stirring at large Prandtl number. We compare our results with the case of variable mobility, in which growth of bubble size is dominated by interfacial rather than bulk effects, and find qualitatively similar results.Comment: 20 pages, 27 figures. RevTeX