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Articles 1 - 6 of 6
Full-Text Articles in Physical Sciences and Mathematics
The Eigenvalues Of A Tridiagonal Matrix In Biogeography, Boris Igelnik, Daniel J. Simon
The Eigenvalues Of A Tridiagonal Matrix In Biogeography, Boris Igelnik, Daniel J. Simon
Electrical and Computer Engineering Faculty Publications
We derive the eigenvalues of a tridiagonal matrix with a special structure. A conjecture about the eigenvalues was presented in a previous paper, and here we prove the conjecture. The matrix structure that we consider has applications in biogeography theory.
Viscosity Of Bacterial Suspensions: Hydrodynamic Interactions And Self-Induced Noise, Shawn D. Ryan, Brian M. Haines, Leonid Berlyand, Falko Ziebert, Igor S. Aranson
Viscosity Of Bacterial Suspensions: Hydrodynamic Interactions And Self-Induced Noise, Shawn D. Ryan, Brian M. Haines, Leonid Berlyand, Falko Ziebert, Igor S. Aranson
Mathematics and Statistics Faculty Publications
The viscosity of a suspension of swimming bacteria is investigated analytically and numerically. We propose a simple model that allows for efficient computation for a large number of bacteria. Our calculations show that long-range hydrodynamic interactions, intrinsic to self-locomoting objects in a viscous fluid, result in a dramatic reduction of the effective viscosity. In agreement with experiments on suspensions of Bacillus subtilis, we show that the viscosity reduction is related to the onset of large-scale collective motion due to interactions between the swimmers. The simulations reveal that the viscosity reduction occurs only for relatively low concentrations of swimmers: Further …
Gut Flora Metabolism Of Phosphatidylcholine Promotes Cardiovascular Disease, Zeneng Wang, Elizabeth Klipfell, Brian J. Bennett, Robert Koeth, Bruce S. Levison, Brandon Dugar, Ariel E. Feldstein, Earl B. Britt, Xiaoming Fu, Yoo Mi Chung, Yuping Wu, Phil Schauer, Jonathan D. Smith, Hooman Allayee, W.H. Wilson Tang, Joseph A. Didonato, Aldons J. Lusis, Stanley L. Hazen
Gut Flora Metabolism Of Phosphatidylcholine Promotes Cardiovascular Disease, Zeneng Wang, Elizabeth Klipfell, Brian J. Bennett, Robert Koeth, Bruce S. Levison, Brandon Dugar, Ariel E. Feldstein, Earl B. Britt, Xiaoming Fu, Yoo Mi Chung, Yuping Wu, Phil Schauer, Jonathan D. Smith, Hooman Allayee, W.H. Wilson Tang, Joseph A. Didonato, Aldons J. Lusis, Stanley L. Hazen
Mathematics and Statistics Faculty Publications
Metabolomics studies hold promise for the discovery of pathways linked to disease processes. Cardiovascular disease (CVD) represents the leading cause of death and morbidity worldwide. Here we used a metabolomics approach to generate unbiased small-molecule metabolic profiles in plasma that predict risk for CVD. Three metabolites of the dietary lipid phosphatidylcholine—choline, trimethylamine N-oxide (TMAO) and betaine—were identified and then shown to predict risk for CVD in an independent large clinical cohort. Dietary supplementation of mice with choline, TMAO or betaine promoted upregulation of multiple macrophage scavenger receptors linked to atherosclerosis, and supplementation with choline or TMAO promoted atherosclerosis. Studies using …
Discrete-Time Recurrent Neural Network And Its Application To Compression Of Infra-Red Spectrum, Leong-Kwan Li, Sally S. L. Shao
Discrete-Time Recurrent Neural Network And Its Application To Compression Of Infra-Red Spectrum, Leong-Kwan Li, Sally S. L. Shao
Mathematics and Statistics Faculty Publications
We study the discrete-time recurrent neural network that derived from the Leaky-integrator model and its application to compression of infra-red spec- trum. Our results show that the discrete-time Leaky-integrator recurrent neural network (RNN) model can be used to approximate the continuous-time model and inherit its dynamical characters if a proper step size is chosen. Moreover, the discrete-time Leaky-integrator RNN model is absolutely stable. By developing the double discrete integral method and employing the state space search algorithm for the discrete-time recurrent neural network model, we demonstrate with quality spectra regenerated from the compressed data how to compress the infra-red spectrum …
Plasma Myeloperoxidase Predicts Incident Cardiovascular Risks In Stable Patients Undergoing Medical Management For Coronary Artery Disease, W.H. Wilson Tang, Yuping Wu, Stephen J. Nicholls, Stanley L. Hazen
Plasma Myeloperoxidase Predicts Incident Cardiovascular Risks In Stable Patients Undergoing Medical Management For Coronary Artery Disease, W.H. Wilson Tang, Yuping Wu, Stephen J. Nicholls, Stanley L. Hazen
Mathematics and Statistics Faculty Publications
BACKGROUND: Myeloperoxidase (MPO) concentrations predict adverse clinical outcomes in the setting of acute coronary syndromes and heart failure, but the prognostic role of MPO in stable patients with known atherosclerotic burden is unclear. METHODS: We examined plasma MPO concentrations and their relationship with prevalent significant coronary artery disease (defined as >50% stenosis in any coronary vessel) and incident major adverse cardiovascular events (MACEs), including death, myocardial infarction, and stroke, in a 3-year prospective follow-up study of 1895 patients undergoing elective coronary angiography. RESULTS: The median plasma MPO concentration was 101 pmol/L (interquartile range 68–187 pmol/L). Patients with plasma MPO concentrations …
Diminished Antioxidant Activity Of High-Density Lipoprotein–Associated Proteins In Systolic Heart Failure, W.H. Wilson Tang, Yuping Wu, Shirley Mann, Michael Pepoy, Kevin Shrestha, Allen G. Borowski, Stanley L. Hazen
Diminished Antioxidant Activity Of High-Density Lipoprotein–Associated Proteins In Systolic Heart Failure, W.H. Wilson Tang, Yuping Wu, Shirley Mann, Michael Pepoy, Kevin Shrestha, Allen G. Borowski, Stanley L. Hazen
Mathematics and Statistics Faculty Publications
Background— Diminished serum arylesterase activity, catalyzed by the high-density lipoprotein–associated paraoxonase-1, is associated with heightened systemic oxidative stress and atherosclerosis risk. In the present study, we sought to determine the prognostic role of serum arylesterase activity in subjects with systolic heart failure, particularly in relation to established cardiac biomarkers. Methods and Results— We measured serum arylesterase activity in 760 subjects with impaired left ventricular systolic function (left ventricular ejection fraction <50%), and prospectively followed major adverse cardiac events (including death, nonfatal myocardial infarction, and stroke) for 3 years. In our study cohort (mean age, 64±11 years; 74% men; median left ventricular ejection fraction, 35%; median creatinine clearance, 96 mg/dL), mean serum arylesterase activity (98±25 μmol/L/min/mL) was lower compared with that in healthy control subjects (mean, 115±26 μmol/L/min/mL, P<0.01) but higher compared with advanced decompensated heart failure subjects (mean, 69±22 μmol/L/min/mL, P<0.01). Within our cohort, there was modest correlation between serum arylesterase activity and high-density lipoprotein cholesterol (r=0.33, P<0.01) as well as B-type natriuretic peptide (r=−0.23, P<0.01). Lower serum arylesterase activity was a strong predictor of poorer outcomes (hazard ratio, 2.94; 95% confidence interval, 1.54, 5.62; P<0.001). After adjusting for traditional risk factors, medication use, B-type natriuretic peptide, and creatinine clearance, lower serum arylesterase still conferred an increased risk of major adverse cardiac events at 3 years (hazard ratio, 2.69; 95% confidence interval, 1.37 to 5.28; P=0.004). Conclusions— In patients with systolic heart failure, decreased serum arylesterase activity, a measure of diminished antioxidant properties of high-density lipoprotein, predicts higher risk of incident long-term adverse cardiac event independent of established clinical and biochemical risk factors.