The Spin Asymmetries of the Nucleon Experiment (SANE) used the Continuous Electron Beam Accelerator Facility at Jefferson Laboratory in Newport News, VA to investigate the spin structure of the proton. The experiment measured inclusive double polarization electron asymmetries using a polarized electron beam, scattered off a solid polarized ammonia target with target polarization aligned longitudinal and near transverse to the electron beam, allowing the extraction of the spin asymmetries A1 and A2, and spin structure functions g1 and g2. Polarized electrons of energies of 4.7 and 5.9 GeV were used. The scattered electrons were detected by a novel, non-magnetic array of detectors observing a four-momentum transfer range of 2.5 to 6.5 GeV*V. This document addresses the extraction of the spin asymmetries and spin structure functions, with a focus on spin structure function, g2 (and g1) at low Bjorken x. The spin structure functions were measured as a function of x and W in four Q square bins. A full understanding of the low x region is necessary to get clean results for SANE and extend our understanding of the kinematic region at low x.

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No abstract Provided / Thesis / Master of Science (MSc)

Concussion is a life-altering injury that can affect people of all ages. Event-related potentials (ERPs) extracted from electroencephalography (EEG) have proven sensitive to concussion-induced cognitive deficits. The MMN, P3a, P3b, and N2b are some ERP components of interest, assessing automatic attention, attentional resource allocation, working memory, and inhibitory executive function, respectively. These ERPs can assess some common symptoms associated with concussion at a level that cannot be attained using self-report. A reduced amplitude and potentially delayed latency of the P3a and P3b is a well-replicated result in concussion research. Furthermore, recent research suggests that an alteration in amplitude of earlier peaks such as the N2b and MMN might represent an irreversible change in cognitive processing that tends to occur in the chronic stages of concussion. Many of these studies have focused on athletes, however little research has evaluated the cognitive effects of sustaining numerous blows to the head that do not result in a clinical diagnosis of concussion, as is the case for many athletes in contact sports. These blows are often referred to as subconcussive impacts. The present study examined the cognitive and neurophysiological effects of subconcussive impacts on collegiate contact-sport athletes and compared them to noncontact athletes. The athletes completed questionnaires to evaluate their health and athletic history, as well as estimates of exposure to subconcussive impacts such as position and playing time, prior to participating in three paradigms meant to assess various cognitive processes during an EEG recording. Across two experiments we demonstrated that subconcussive impacts within a season of play can result in alterations in neurophysiological markers of cognitive health. Our findings also reveal that continued involvement in contact sports can have serious implications in one’s automatic attention, resource allocation, and working memory as demonstrated by reduced ERP amplitudes in contact as compared to non-contact athletes. / Thesis / Master of Science (MSc) / A concussion is a devastating injury that can greatly affect how an individual functions in their day-to-day life. Concussions are often discussed in the context of contact sports because of these athletes’ exposure to repeated head impacts. That said, another cause for concern is the effects of head impacts that do not result in a concussion per se – these are known as subconcussive impacts. A brain imaging technique known as electroencephalography (EEG) involves recording brain activity from sensors on the head. Conducting this recording while individuals perform tasks known to evaluate brain function offers an opportunity to assess symptoms rather than relying on a patient’s own, subjective report of their experiences. The present study investigated the use of EEG in evaluating the effects of subconcussive impacts in collegiate athletes and found that repeated head impacts can reduce cognitive health, even if they do not result in a diagnosis of concussion.

With the aging of the baby boom population and an increased life expectancy, individuals aged 65 years and older are the fastest growing segment of our population. Aging brings about changes in skeletal muscle such as reduced muscle strength and mass, as well as cellular deficits such as increased production of reactive oxygen species (ROS), and mitochondrial DNA (MtDNA) deletions and mutations. Muscle mass declines at a rate of 1-2% each year after the age of 50, leading to muscle weakness, functional impairments, loss of independence, and an increase in falls. Additional declines in muscle mass and reduced muscle strength may result in a lower resting metabolic rate, reduced lipid oxidative capacity, increased adiposity, and insulin resistance. The rising number of individuals aged 65+ will increase demands on health care and health care costs, possibly leading to inadequate public resources and less care for the aged. This large societal impact, coupled with the aging of our population, suggests a clear need for methods that will improve the aging phenotype to enhance functionality, quality of life, and overall health for our aging population. This investigation aspires to delve into a relatively unexplored area of aging research and evaluate potential means that could help improve the aging phenotype. The associated mitochondrial impairments, mitochondrial mediated apoptosis, and mitochondrial DNA (MtDNA) deletions and mutations that accompany aging lead to a decline in physical fitness and oxidative capacity, and exercise has been shown to reverse or help prevent many of these disturbances. Resistance exercise training (RT) is currently the most effective known strategy to stimulate skeletal muscle hypertrophy and increase strength. Strength gains after RT lead to an improvement in activities of daily living and quality of life. There is some evidence suggesting that RT may lead to increased antioxidant enzyme capacity, decreased ROS production and increased electron transport chain (ETC) function in older individuals. The present study will lay a foundation for future research and further developments in the area of RT, mitochondrial function and aging. / Ph. D.

Random variables defined on the natural numbers may often be approximated by Poisson variables. Just as normal approximations may be improved by saddlepoint methods, Poisson approximations may be substantially improved by tilting, expansion, and other related methods. This work will develop and examine the use of these methods, as well as present examples where such methods may be needed. / Ph. D.