2001-2002 Lynn University String Orchestra

https://spiral.lynn.edu/conservatory_otherseasonalconcerts/1099/thumbnail.jp

Selection, Stability and Renormalization

We illustrate how to extend the concept of structural stability through applying it to the front propagation speed selection problem. This consideration leads us to a renormalization group study of the problem. The study illustrates two very general conclusions: (1) singular perturbations in applied mathematics are best understood as renormalized perturbation methods, and (2) amplitude equations are renormalization group equations.Comment: 38 pages, LaTeX, two PostScript figures available by anonymous ftp to gijoe.mrl.uiuc.edu (128.174.119.153) files /pub/front_kkfest_fig

Structural Stability and Renormalization Group for Propagating Fronts

A solution to a given equation is structurally stable if it suffers only an infinitesimal change when the equation (not the solution) is perturbed infinitesimally. We have found that structural stability can be used as a velocity selection principle for propagating fronts. We give examples, using numerical and renormalization group methods.Comment: 14 pages, uiucmac.tex, no figure

Characterization of AlInN layer grown on GaN/Sapphire substrate by MOCVD

The AlInN layers have been grown with different growth parameters on GaN/sapphire substrates by metal-organic chemical vapor deposition (MOCVD). The effects of growth parameters such as pressure and temperature on the Al incorporation during AlInN material growth have been investigated. The results showed that lower pressure provides a tendency for higher Al incorporating in the AlInN layer. Besides, as the temperature was increased from 700°C to 780°C, an estimation of 4% reduction on the indium composition has been observed for each 20°C increment. XRD analysis showed that the best crystal quality of AlInN occured at 80% Al composition because of the higher lattice matching with GaN. Based on the above criteria, an Al0.8In0.2N/GaN HEMT device with 2 μm gate length has also been fabricated. The DC characteristics showed a saturated current, Idss of 280 mA/mm and transconductance of 140 mS/mm

RISK FACTORS OF ARTERIAL THROMBOEMBOLISM IN HOSPITALIZED COVID-19 PATIENTS: A MULTICENTER COHORT STUDY

Background: Endothelial cell dysfunction from infection by SARS-CoV-2 and inflammatory cytokines leading to hyperinflammatory and hypercoagulable state is thought to be the mechanism of arterial thromboembolism (ATE) in COVID-19 patients. COVID-19 infection is known to be an independent risk factor for acute stroke and myocardial infarction (MI). However, data on the risk factors of ATE in hospitalized COVID-19 patients is limited. Methods: This retrospective, multicenter cohort study included adult patients admitted to one quaternary care and three community hospitals with PCR-proven SARS-CoV-2 infection between 3/1/2020 and 12/31/2020. The composite outcome was in-hospital ATE events, including acute ischemic stroke, MI, and other ATE identified by ICD-10 codes. Student t-test was conducted for continuous variables and the Chi-square test for categorical variables. Multivariate logistic regression using forward selection was conducted. All statistical tests were 2-sided with an α level of 0.05. All data was analyzed using R version 4.0.4. Results: The cohort included 3531 patients with 371 (10.5%) patients who developed acute ATE. There were 398 ATE events: 270 patients had MI, 43 had stroke, 85 had other ATE, 12 had MI + stroke, 13 had MI + other ATE, and 2 had stroke + other ATE. The model suggested that initial systolic blood pressure (BP) \u3c90 mmHg and \u3e160 mmHg; elevated initial biomarkers including B-type natriuretic peptide (\u3e100 pg/mL), troponin-I (\u3e0.03 ng/mL), lactate dehydrogenase (\u3e192 U/L), creatine phosphokinase (male \u3e280 U/L and female \u3e155 U/L), C-reactive protein (\u3e0.5 mg/dL), leukocytes (\u3e11 K/uL), lactate (\u3e2.2 mmol/L), and aspartate aminotransferase (\u3e41 U/L); presenting hypoalbuminemia (\u3c3.5 g/dL) and hypomagnesemia (\u3c1.8 mg/dL); age \u3e60; male sex; and history of cerebrovascular accident (CVA), coronary artery disease (CAD), hyperthyroidism, and cigarette smoking were associated with an increased risk of ATE (all p\u3c0.05). Conclusion: Hypo or hypertension on admission, elevated inflammatory and cardiac markers, hypoalbuminemia, hypomagnesemia, smoking, and comorbidities including CAD and CVA are associated with ATE in hospitalized COVID-19 patients

Renormalization Group Theory And Variational Calculations For Propagating Fronts

We study the propagation of uniformly translating fronts into a linearly unstable state, both analytically and numerically. We introduce a perturbative renormalization group (RG) approach to compute the change in the propagation speed when the fronts are perturbed by structural modification of their governing equations. This approach is successful when the fronts are structurally stable, and allows us to select uniquely the (numerical) experimentally observable propagation speed. For convenience and completeness, the structural stability argument is also briefly described. We point out that the solvability condition widely used in studying dynamics of nonequilibrium systems is equivalent to the assumption of physical renormalizability. We also implement a variational principle, due to Hadeler and Rothe, which provides a very good upper bound and, in some cases, even exact results on the propagation speeds, and which identifies the transition from ` linear'- to ` nonlinear-marginal-stability' as parameters in the governing equation are varied.Comment: 34 pages, plain tex with uiucmac.tex. Also available by anonymous ftp to gijoe.mrl.uiuc.edu (128.174.119.153), file /pub/front_RG.tex (or .ps.Z

Intraseasonal variation of the East Asian summer monsoon associated with the MJO

We investigate the daily variability of the East Asian summer monsoon (EASM) by projecting daily wind anomaly data onto the two major modes of an interannual multivariate Empirical Orthogonal Functions analysis. Mode 1, closely resembling the Pacific-Japan (PJ) pattern and referred to as PJ-mode, transits from positive to negative phase around mid-summer consistent with the Meiyu rains predominantly being an early summer phenomenon. Mode 2, which is influenced by the Indian summer monsoon (ISM) and referred to as ISM-mode, peaks in late July and early August and is associated with rainfall farther north over China. We then analyze the relation between the intraseasonal variation of the EASM and the Madden-Julian Oscillation (MJO) by analyzing circulation anomalies following MJO events. In the lower troposphere, the circulation anomalies associated with the MJO most strongly project on the PJ-mode. MJO phases 1-4 (5-8) favor the positive (negative) phase of the PJ-mode by favoring the anticyclonic (cyclonic) anomalies over the subtropical western North Pacific. In the upper troposphere, the circulation anomalies associated with the MJO project mainly on the ISM-mode

Association Between Platelet Count and Components of Metabolic Syndrome in Geriatric Taiwanese Women

SummaryBackgroundThe growing elderly population in Taiwan, as in many other countries, has resulted in increased importance of the metabolic syndrome (MetS). Although it has been reported in different age groups, the relationship between platelets and MetS remains unknown in geriatric patients.Patients and MethodsWe enrolled 1460 women >65 years old. Women with a known history of diabetes, hyperlipidemia or hypertension or those taking medication for these conditions were all excluded. The women were further divided into quartiles arbitrarily according to platelet count (PC) (PC1–PC4, lowest to highest accordingly).ResultsAmong the MetS components, body mass index (BMI), total cholesterol, low-density lipoprotein cholesterol (LDL-C) and log transformation triglyceride (Log TG) were all significantly higher in the PC4 group (p < 0.05), and they were also positively correlated with PC. However, in multiple regression, BMI became nonsignificant. Both LDL-C and Log TG were the only two factors that remained positively and independently correlated with PC. Compared to PC1, all the other three groups had significantly higher odds ratios for having MetS (2.013, 1.473–2.751; 1.486, 1.081–2.042; 1.537, 1.117–2.114; odds ratios and 95% confidence intervals for PC4, PC3 and PC2, respectively).ConclusionElderly women with MetS had higher PC. Among the five components, TG was positively correlated with PC. There was a positive correlation between PC and LDL-C but not high-density lipoprotein cholesterol. The importance of both lipids might be re-evaluated in the future in older women

Zonal Momentum Balance in the Tropical Atmospheric Circulation during the Global Monsoon Mature Months

In this paper, zonal momentum balances of the tropical atmospheric circulation during the global monsoon mature months (January and July) are analyzed in three dimensions based on the ECMWF Interim Re-Analysis (ERA-Interim). It is found that the dominant terms in the balance of the atmospheric boundary layer (ABL) in both months are the pressure gradient force, the Coriolis force, and friction. The nonlinear advection term plays a significant role only in the Asian summer monsoon regions within the ABL. In the upper troposphere, the pressure gradient force, the Coriolis force, and the nonlinear advection are the dominant terms. The transient eddy force and the residual force (which can be explained as convective momentum transfer over open oceans) are secondary, yet cannot be neglected near the equator. Zonal-mean equatorial upper-troposphere easterlies are maintained by the absolute angular momentum advection associated with the cross-equatorial Hadley circulation. Equatorial upper-troposphere easterlies over the Asian monsoon regions are also controlled by the absolute angular momentum advection but are mainly maintained by the pressure gradient force in January. The equivalent linear Rayleigh friction, which is widely applied in simple tropical models, is calculated and the corresponding spatial distribution of the local coefficient and damping time scale are estimated from the linear regression. It is found that the linear momentum model is in general capable of crudely describing the tropical atmospheric circulation dynamics, yet the caveat should be kept in mind that the friction coefficient is not uniformly distributed and is even negative in some regions

Understanding advances in the simulation of intraseasonal variability in the ECMWF model. Part I: the representation of the MJO

As a major mode of intraseasonal variability, which interacts with weather and climate systems on a near-global scale, the Madden – Julian Oscillation (MJO) is a crucial source of predictability for numerical weather prediction (NWP) models. Despite its global significance and comprehensive investigation, improvements in the representation of the MJO in an NWP context remain elusive. However, recent modifications to the model physics in the ECMWF model led to advances in the representation of atmospheric variability and the unprecedented propagation of the MJO signal through the entire integration period. In light of these recent advances, a set of hindcast experiments have been designed to assess the sensitivity of MJO simulation to the formulation of convection. Through the application of established MJO diagnostics, it is shown that the improvements in the representation of the MJO can be directly attributed to the modified convective parametrization. Furthermore, the improvements are attributed to the move from a moisture-convergent- to a relative-humidity-dependent formulation for organized deep entrainment. It is concluded that, in order to understand the physical mechanisms through which a relative-humidity-dependent formulation for entrainment led to an improved simulation of the MJO, a more process-based approach should be taken. T he application of process-based diagnostics t o t he hindcast experiments presented here will be the focus of Part II of this study