158 research outputs found
Some Irrational Generalised Moonshine from Orbifolds
We verify the Generalised Moonshine conjectures for some irrational modular
functions for the Monster centralisers related to the Harada-Norton, Held,
and simple groups based on certain orbifolding constraints.
We find explicitly the fixing groups of the hauptmoduls arising in each case
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The Mortgage‐Cash Premium Puzzle
ABSTRACT:
All‐cash homebuyers account for one‐third of U.S. home purchases between 1980 and 2017. We use multiple data sets and research designs to robustly estimate that mortgaged buyers pay an 11% premium over all‐cash buyers to compensate home sellers for mortgage transaction frictions. A dynamic, representative‐seller model implies only a 3% premium, which would suggest an 8% puzzle. Accounting for heterogeneity in selling conditions explains half of this difference, but a puzzle holds in conditions with high transaction risk. An experimental survey of U.S. homeowners replicates these patterns and suggests that belief distortions can explain the puzzle in these high‐risk states
Parametric Portfolio Policies: Exploiting Characteristics in the Cross Section of Equity Returns
We propose a novel approach to optimizing portfolios with large numbers of assets. We model directly the portfolio weight in each asset as a function of the asset's characteristics. The coefficients of this function are found by optimizing the investor's average utility of the portfolio's return over the sample period. Our approach is computationally simple, easily modified and extended, produces sensible portfolio weights, and offers robust performance in and out of sample. In contrast, the traditional approach of first modeling the joint distribution of returns and then solving for the corresponding optimal portfolio weights is not only difficult to implement for a large number of assets but also yields notoriously noisy and unstable results. Our approach also provides a new test of the portfolio choice implications of equilibrium asset pricing models. We present an empirical implementation for the universe of all stocks in the CRSP-Compustat dataset, exploiting the size, value, and momentum anomalies.
Generalized Moonshine and Orbifold Constructions
A brief review is given of some of our recent work on Generalised Monstrous Moonshine using abelian orbifoldings of the Moonshine Module
Benefits and Risks of Weight-Loss Treatment for Older, Obese Women
Background: A key issue in the treatment of obesity in older adults is whether the health benefits of weight loss outweigh the potential risks with respect to musculoskeletal injury. Objective: To compare change in weight, improvements in metabolic risk factors, and reported musculoskeletal adverse events in middle-aged (50-59 years) and older (65-74 years), obese women. Materials and methods: Participants completed an initial 6-month lifestyle intervention for weight loss, comprised of weekly group sessions, followed by 12 months of extended care with biweekly contacts. Weight and fasting blood samples were assessed at baseline, month 6, and month 18; data regarding adverse events were collected throughout the duration of the study. Results: Both middle-aged (n = 162) and older (n = 56) women achieved significant weight reductions from baseline to month 6 (10.1 +/- 0.68 kg and 9.3 +/- 0.76 kg, respectively) and maintained a large proportion of their losses at month 18 (7.6 +/- 0.87 kg and 7.6 +/- 1.3 kg, respectively); there were no significant differences between the two groups with respect to weight change. Older women further experienced significant reductions in systolic blood pressure, HbA(1c), and C-reactive protein from baseline to month 6 and maintained these improvements at month 18. Despite potential safety concerns, we found that older women were no more likely to experience musculoskeletal adverse events during the intervention as compared with their middle-aged counterparts. Conclusion: These results suggest that older, obese women can experience significant health benefits from lifestyle treatment for obesity, including weight loss and improvements in disease risk factors. Further investigation of the impact of weight loss on additional health-related parameters and risks (eg, body composition, muscular strength, physical functioning, and injuries) in older adults is needed.National Heart, Lung and Blood Institute R18HL73326University of FloridaDivision of Statistics and Scientific Computatio
Effect of adenosine antagonism on metabolically mediated coronary vasodilation in humans
AbstractObjectives. This study was performed io assess the importance of adenosine in mediating metabolic coronary vasodilation during atrial pacing stress in humans.Background. Numerous animal studies have examined the role of adenosine in the regulation of coronary blood flow, with inconsistent results.Methods. The effect of the adenosine antagonist aminophylline (6 mg/kg body weight intravenously) on coronary functional hyperemia during rapid atrial pacing was determined in 12 patients. The extent of inhibition of adenosine vasodilation was assessed using graded intracoronary adenosine infusions before and after aminophylline administration in seven patients. Coronary blood flow changes were measured with a 3F intracoronary Doppler catheter.Results. After aminophylline administration, the increase in coronary flow velocity during adenosine infusions was reduced from 84 ± 48% (mean ± SD) to 21 ± 31% above control values (p < 0.001) at 10 μg/min and from 130 ± 39% to 59 ± 51% above control values (p < 0.001) at 40 μg/min. During rapid atrial pacing under control conditions, coronary blood flow velocity increased by 26 ± 16%. The flow increment during paced tachycardia after aminophylline (23 ± 10%) was unchanged from the control value, despite substantial antagonism of adenosine coronary dilation by aminophylline.Conclusions. These data suggest that adenosine does not play an important role in the regulation of coronary blood flow in response to rapid atrial pacing in humans
Rational Generalised Moonshine from Abelian Orbifoldings of the Moonshine Module
We consider orbifoldings of the Moonshine Module with respect to the abelian
group generated by a pair of commuting Monster group elements with one of prime
order and the other of order for or prime. We show
that constraints arising from meromorphic orbifold conformal field theory allow
us to demonstrate that each orbifold partition function with rational
coefficients is either constant or is a hauptmodul for an explicitly found
modular fixing group of genus zero. We thus confirm in the cases considered the
Generalised Moonshine conjectures for all rational modular functions for the
Monster centralisers related to the Baby Monster, Fischer, Harada-Norton and
Held sporadic simple groups. We also derive non-trivial constraints on the
possible Monster conjugacy classes to which the elements of the orbifolding
abelian group may belong.Comment: 40 pages, Improved versio
Innovative and rapid antimicrobial susceptibility testing systems
Antimicrobial resistance (AMR) is a major threat to human health worldwide, and the rapid detection and quantification of resistance, combined with antimicrobial stewardship, are key interventions to combat the spread and emergence of AMR. Antimicrobial susceptibility testing (AST) systems are the collective set of diagnostic processes that facilitate the phenotypic and genotypic assessment of AMR and antibiotic susceptibility. Over the past 30 years, only a few high-throughput AST methods have been developed and widely implemented. By contrast, several studies have established proof of principle for various innovative AST methods, including both molecular-based and genome-based methods, which await clinical trials and regulatory review. In this Review, we discuss the current state of AST systems in the broadest technical, translational and implementation-related scope
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