The modularity of a certain Calabi-Yau threefold and supercongruences for truncated hypergeometric series

Mortenson, Eric Todd The University of Wisconsin - Madison 2003 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

We prove that a certain Calabi-Yau threefold is modular, and we prove supercongruences for truncated <italic>_n</italic>₊₁<italic>F_n</italic>, hypergeometric functions. In first half of the thesis, we reprove the modularity of a certain Calabi-Yau threefold. This method uses the Eichler-Selberg trace formula for Hecke Operators. The three-fold in question was orginally constructed and studied by Verrill. In the second half of the thesis, we prove supercongruences between truncated <italic>_n</italic>₊₁<italic>F_n</italic> hypergeometric series and their character sum analogs. We then use these supercongruences to prove several Beukers type supercongruence conjectures of Fernando Rodriguez-Villegas. In these conjectures, Rodriguez-Villegas relates families of hypergeometric functions to certain families of Calabi-Yau manifolds.

Encapsulation and real-time release characteristics of spray dried l-menthol

Mortenson, Michael Alan University of Minnesota 2008 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

The objective of this research was to understand the effects of octenyl succinic anhydride (OSAn) substitution level of carbohydrate encapsulation materials on the capsule characteristics and real-time release of l-menthol from spray dried powder. Spray dried l-menthol powder was prepared from modified dextrin and gum acacia of varying levels of OSAn substitution. Physical properties of the microcapsules and encapsulation matrices were determined by: constructing moisture sorption isotherms, particle sizing, density measurement via pycnometry, and by total and surface menthol content of the finished powders. Real-time menthol release and moisture uptake profiles were accomplished by using dynamic vapor sorption (DVS) coupled with either Tenax trapping and gas chromatography (GC) or proton transfer reaction mass spectrometry (PTR-MS). It was found that as OSAn substitution of carbohydrates increases, total and surface menthol appeared to increase and decrease, respectively. The particle size of the finished spray dried powder was influenced by spray dryer infeed solids concentration with higher solids leading to larger particle size. Microcapsule density did not appear to be affected by OSAn substitution or carrier type. Menthol release profiles varied greatly with carrier material used. Increased OSAn substitution (up to 3% treatment level) of the carrier material resulted in a significantly greater, but not earlier burst of menthol release. For most samples, the characteristic burst of menthol was followed by a decrease in release which was attributed to an observed matrix collapse. Moisture uptake rates of the powders were related to corresponding menthol release rates. As OSAn substitution increased for gum acacia (Acacia seyal), a trend of increased moisture uptake rate with menthol release rate was evident. However, for the dextrins, the moisture uptake rate had no influence on the rate of menthol release. The degree of OSAn substitution did not affect moisture sorption characteristics for dextrin samples. For gum acacia, increased levels of OSAn substitution resulted in a decreased affinity for moisture in the range of 0.3 to 0.7 a w.

Essays on Responses to Income Taxation in the United States

Mortenson, Jacob Georgetown University 2016 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

Federal income taxes on individual income in the United States raised over $1.5 trillion in revenue in 2015. This represents just under half of all tax revenue collected by the federal government. Returns to saving and working are affected by income taxes, and understanding the responses of individuals to them is crucial to evaluating their welfare and revenue consequences. In this dissertation, I study individual income responses to federal income taxes in the United States. In the first chapter of this dissertation, I estimate the responsive of capital gains realizations and ordinary income in the United States to changes in marginal tax rates on both types of income. I use a large non-public panel of federal income tax returns from 1997-2007, and find two key results, though both are sensitive to a variety of specification decisions. First, capital gains respond to both the capital gains tax rate and the ordinary income tax rate. Second, I find mixed evidence that ordinary income responds to the ordinary income tax rate and the long-term capital gains tax rate. These results suggest cross-tax responses between these two bases are important, and should not be ignored when estimating taxpayer responses in the United States. The second chapter of this dissertation investigates how taxpayers respond to changes within the tax schedule. One way taxpayers may respond is by bunching at kink points in the tax schedule to avoid high marginal tax rates. We study this phenomenon using over 500 million federal individual income tax returns in the United States from 1996 to 2014. Though most kinks do not cause statistically discernible bunching, we present new evidence documenting the emergence and rapid rise of bunching at the second Earned Income Tax Credit (EITC) kink and the Child Tax Credit refundability plateau, strong responses to the temporary Making Work Pay Tax Credit, and weak responses at three statutory kinks. Consistent with prior research, we also observe bunching at the first kink in the EITC schedule. The majority of bunchers are self-employed, though we find significant bunching among wage earners in recent years. Substantial bunching responses occur only at kinks that maximize tax credits, and the strongest response occurs at the unique point in the schedule that maximizes credits net of taxes owed. The third chapter of this dissertation examines withdrawal patterns from traditional Individual Retirement Accounts (IRAs). In 2013, individuals age 60 or older held $3.9 trillion in wealth in these IRAs. Under current law, some fraction of these funds must be withdrawn each year beginning the year one turns 70.5 years of age, with the required fraction increasing in age. We study the effects of these Required Minimum Distribution (RMD) rules on the decumulation behavior of retirees using a 16-year panel of administrative tax data. Our data consist of a 5% random sample of individuals age 60 and older from 1999 to 2014: approximately 2.6 million individuals per year. This period encompasses a unique policy change that we exploit for identification: a one-year suspension of the RMD rules in 2009. Using a semiparametric technique we estimate the counterfactual density of IRA distributions in 2009 that would have prevailed if the rules had not been suspended. We estimate that at least 40% of the individuals subject to the RMD rules would take an IRA distribution less than their required minimum if they were unconstrained. In addition, we document an extensive margin effect among individuals newly subject to the rules.

Development and evaluation of a clinical practice guideline to promote evidence-based treatment of pediatric concussions in primary care

Mortenson, Brett Jerome The University of Arizona 2016 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

Introduction and Rationale: Concussions account for the majority of traumatic brain injuries in children. Currently there more than 500,000 pediatric concussions per year and that number is likely low due to under-reporting (Rose, Weber, Collen, & Heyer, 2015). Most symptoms of concussion are easily recognized to the trained pediatric primary care provider. Yet, symptom management and recommendations for rest, exercise, specialty care referral, and return to normal activities can be challenging for many providers, due to the lack of evidence and lack of formal recommendations by any organization (Rose et al., 2015; Silverberg & Iverson, 2013). Purpose and Objective: The main purpose of this Doctor of Nursing Practice (DNP) project is to develop evidence-based clinical practice guidelines (CPG) for pediatric primary care providers. The objective is to provide a CPG that offers clinical guidance when managing pediatric concussion patients in the primary care setting. This CPG will also provide clarity for pediatric primary care providers (PCP) when determining what options are available in treatment for pediatric concussions. Methods: The working framework of this project was The Appraisal of Guidelines for Research & Evaluation II (AGREE II). The American Academy of Pediatrics (AAP) procedure for reporting clinical guidelines, in the form of key action statements, was used as the model for development of the CPG. Results: The CPG was appraised using the AGREE II instrument, which provides valid and reliable scores and data used in the evaluation of CPG's. Six domains were evaluated, and the CPG yielded scores above 80% for all categories. The overall standard deviation was 0, which indicts a very low level of discrepancy between users of the instrument. Conclusion: This DNP project addresses an evidence and primary care practice gap. With a large number of pediatric concussions, a consistent management approach will ensure a safe and therapeutic recovery. A CPG was developed and evaluated using the AGREE II instrument. The CPG was found to meet the standards for general recommended use in pediatric primary care.

Living face to face with breathlessness: An interpretive study of low income families' management practices in Latino and African-American infants and toddlers with severe persistent asthma

Koenig, Karel Mortenson University of California, San Francisco 1999 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

Despite new understanding of disease pathology, and new, more effective medicines and delivery systems, asthma morbidity continues to rise among infants and toddlers, especially in low income and ethnically diverse families. Long-held, widespread belief persists that home management failure explains high rates of morbidity. However, the experience, understandings, and caregiving skills of parents are largely unexamined. This interpretive investigation examined how low income Latino and African-American parents of children hospitalized for asthma or reactive airway disease understood and managed asthma in their 12 month to 4 year-old children with severe persistent asthma. Eleven families participated in three home interviews that focused on narratives of care, and from two to five home observations of family interaction during a 3 to 5 month period. Families coped with caregiving responsibility, family stressors, and multiple daily hassles related to poverty. Although asthma immersed parents and children in world defining fear, parents relied less on professional providers than on themselves in making assessments and taking steps to access care. Four distinct patterns of self-agency for managing asthma were found. Parents with <italic>determined self-agency</italic> managed asthma with the goal of self-sufficiency. Feeling overwhelmed when symptoms flared into crisis, parents practicing <italic>discontinuous self-agency</italic> relinquished care to professionals. Parents who practiced <italic>flexible self-agency </italic> devised varied strategies to treat crises and access care, while sharing responsibility with professionals whom they did not fully trust. Two single mothers practiced <italic>self-agency disrupted</italic> by more critical life concerns. Asthma management was important only during, and immediately following, crisis. Frightened for their child's life during severe breathing crisis, parents experienced hospital management as additionally traumatizing for their child. Since most felt their daily management practices were disrespected and misunderstood by crisis care providers, parents dreaded future hospitalizations and worked to avoid emergency visits. Findings point to a need for professionals to join with parents to improve asthma care. National Institutes Guidelines regarding early treatment and referral for specialist care were not followed for children in this study.