155 research outputs found

    The structure of Gelfand-Levitan-Marchenko type equations for Delsarte transmutation operators of linear multi-dimensional differential operators and operator pencils. Part 1

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    An analog of Gelfand-Levitan-Marchenko integral equations for multi- dimensional Delsarte transmutation operators is constructed by means of studying their differential-geometric structure based on the classical Lagrange identity for a formally conjugated pair of differential operators. An extension of the method for the case of affine pencils of differential operators is suggested.Comment: 12 page

    Long Term Outcome of Childhood Bicuspid Aortic Valve

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    The most common congenital heart defect is a bicuspid aortic valve (BAV), which is often genetic and the cause is unknown. The defect occurs in only 1% of the general population. A BAV is not able to fully stop blood from leaking back into the heart, which is known as aortic regurgitation. Another common issue with a BAV is that it may be too stiff to fully open, which is known as aortic stenosis. In early childhood, children with aortic stenosis often need palliation with a balloon or surgical valvotomy. As these children develop, they may need subsequent, more definitive procedures such as a Ross procedure, insertion of a tissue valve or mechanical valve, or a valve repair. These definitive operations are used to address recurrent aortic stenosis or regurgitation. As a result, comparing the long-term complications of valve interventions in infancy was an area of considerable interest. The goal of this study was to compare whether one procedure is more effective in providing a more functional status in adulthood since comparative data on the morbidity and mortality associated with each definitive repair in a contemporaneous cohort is lacking. Clinical evidence suggests that repeat surgical procedures are very common in all surgical interventions for bicuspid aortic valve with aortic stenosis in childhood. Incidences of a greater number of aortic valve surgery is associated with a higher incidence of surgical complications and endocarditis. Long-term follow up on the odds of a composite adverse outcome are less with a Ross procedure.https://digitalcommons.unmc.edu/surp2021/1011/thumbnail.jp

    Sociodemographic, Anthropometric, and Psychosocial Predictors of Attrition across Behavioral Weight-Loss Trials.

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    Preventing attrition is a major concern in behavioral weight loss intervention studies. The purpose of this analysis was to identify baseline and six-month predictors associated with participant attrition across three independent clinical trials of behavioral weight loss interventions (PREFER, SELF, and SMART) that were conducted over 10 years. Baseline measures included body mass index, Barriers to Healthy Eating, Beck Depression Inventory-II (BDI), Hunger Satiety Scale (HSS), Binge Eating Scale (BES), Medical Outcome Study Short Form (MOS SF-36 v2) and Weight Efficacy Lifestyle Questionnaire (WEL). We also examined early weight loss and attendance at group sessions during the first 6 months. Attrition was recorded at the end of the trials. Participants included 504 overweight and obese adults seeking weight loss treatment. The sample was 84.92% female and 73.61% white, with a mean (± SD) age of 47.35 ± 9.75 years. After controlling for the specific trial, for every one unit increase in BMI, the odds of attrition increased by 11%. For every year increase in education, the odds of attrition decreased by 10%. Additional predictors of attrition included previous attempts to lose 50–79 lbs, age, not possessing health insurance, and BES, BDI, and HSS scores. At 6 months, the odds of attrition increased by 10% with reduced group session attendance. There was also an interaction between percent weight change and trial (p < .001). Multivariate analysis of the three trials showed education, age, BMI, and BES scores were independently associated with attrition (ps ≤ .01). These findings may inform the development of more robust strategies for reducing attrition
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