2,694 research outputs found
Insulin sensitivity from meal tolerance tests in normal subjects: a minimal model index
No full textIn this report a new approach is introduced that allows estimation of insulin sensitivity (S(I)) from orally ingested glucose during an oral glucose tolerance test (OGTT) or a meal glucose tolerance test (MGTT) in normal subjects. The method hinges on the classic minimal model of glucose kinetics that is coupled with an equation describing the rate of appearance of glucose into the circulation after oral glucose ingestion. The model provides an estimate of S(I) in a given individual based on simple area under the curve type of calculations. To prove the reliability of the new approach, MGTT studies performed in 10 normal subjects were analyzed and the S(I) index from the MGTT was compared with the S(I) index obtained in the same subjects from an insulin-modified, frequently sampled iv glucose test (FSIGT). S(I) from the MGTT was 13.6+/-3.9 x 10(-4) dL/kg x min/microU x mL and was strongly correlated to the S(I) from the FSIGT (rs = 0.89; P < 0.01). In conclusion, this study shows that in normal subjects the minimal model can be applied to a MGTT/OGTT to derive an index of insulin sensitivity that is in good agreement with the one estimated from the FSIGT. Due to its simplicity, this method has potential for use in population studies, but further investigation is required to ascertain its applicability to subjects with severe insulin resistance and impaired secretory function
Quantitative estimation of insulin sensitivity.
No full textWe have evaluated the feasibility of using a mathematical model of glucose disappearance to estimate insulin sensitivity. Glucose was injected into conscious dogs at 100, 200, or 300 mg/kg. The measured time course of insulin was regarded as the "input," and the falling glucose concentration as the "output" of the physiological system storing and using glucose. Seven mathematical models of glucose uptake were compared to identify the representation most capable of simulating glucose disappearance. One specific nonlinear model was superior in that it 1) predicted the time course of glucose after glucose injection, 2) had four parameters that could be precisely estimated, and 3) described individual experiments with similar parameter values. Insulin sensitivity index (SI), defined as the dependence of fractional glucose disappearance on plasma insulin, was the ratio of two parameters of the chosen model and could be estimated with good reproducibility from the 300 mg/kg injection experiments (SI = 7.00 X 10(-4) +/- 24% (coefficient of variation) min-1/(microU/ml) (n = 8)). Thus, from a single glucose injection it is possible to obtain a quantitative index of insulin sensitivity that may have clinical applicability
Commutators and Related Operators on Harmonic Bergman Space of Rn+1+
No full textAbstractWe study commutators and related operators on harmonic Bergman space—theL2(Rn+1+) closure of the null space of Laplacian. By decomposingL2(Rn+1+) into the sum of null spaces of powers of Laplacian, and using the theory of paracommutators studied in [JP], we characterize harmonic symbols for which the associated commutators are bounded or compact. Operators associated to the Div–Curl theorem (in [CLMS]) in the theory of compensated compactness are also characterized
Spring 2021 HIP with a virtual literature review experience with an RN-BSN Student
No full textRegistered Nurse-Bachelor of Science in Nursing (RN-BSN) students have been caring for critically ill COVID-19 patients for over a year, while remaining dedicated to advancing their education. Nurse burnout has increased with the COVID-19 stressors adding to the critical nursing shortages throughout the nation (Kelly et al., 2021). Caring mentorship supports the RN-BSN student needs as a working nurse enduring pandemic stressors
How-to guides for first time staff RN researchers, from staff RN researcher, published author
No full textAdvice and tips from a first time bedside staff RN researcher/ published author to potential staff RN researchers/ authors on how to start, fund, form teams, gather and analyze data, submit completed research project for conferences and publication
Projections for harmonic Bergman spaces and applications
No full textAbstractOn the setting of general bounded smooth domains in Rn, we construct L1-bounded nonorthogonal projections and obtain related reproducing formulas for the harmonic Bergman spaces. In addition, we show that those projections satisfy Sobolev Lp-estimates of any order even for p=1. Among applications are Gleason's problems for the harmonic Bergman–Sobolev and (little) Bloch functions on star-shaped domains with strong reference points
Boundedness of Bergman projections on tube domains over light cones
No full textLet Γ be the future light cone in Rn, and Ω = Rn + iΓ be the associated tube domain. We prove that the weighted Bergman projection Pv pvf(z) = ∫Ω f(w)Q(z - w̄)-vQ(script T signmw)v-ndw is bounded on Lp(Ω, Qv-n(script T signmw)dw) for 1 + n-2/2(v-1) < p < 1 + 2(v-1)/n-2, where Q denotes the Lorentz quadratic form. This theorem extends previous results by Bekollé and Bonami [BB]. Our proof relies on the analysis of the projection Pv, on mixed norm spaces, which allows us to exploit the oscillation of the Bergman kernel using the Laplace-Fourier transform
Bolfuncties in Rn: Spherical harmonics in Rn
No full textIn de wiskunde hebben we bij het modelleren van fysische problemen vaak te maken met randwaardeproblemen. Voor een randwaardeprobleem met een cirkel als rand en een L2- functie als randvoorwaarde, kan deze randvoorwaarde beschreven worden door een Fourierreeks. Hierdoor kan zo'n randwaardeprobleem makkelijker opgelost worden. In dit werk wordt het uitdrukken van functies in Fourierreeksen in R2 uitgebreid naar Rn door bolfuncties in Rn te gebruiken. Eerst wordt er een introductie gegeven in bolfuncties in R2 en er wordt een aantal nuttige eigenschappen van deze functies besproken. Vervolgens worden enkele handigheden voor het werken in Rn genoemd en komen de kwadratisch integreerbare functies aan bod. Tot slot zien we dat de eigenschappen van de bolfuncties in R2 nog steeds gelden in Rn en dat elke kwadratisch integreerbare functie op de eenheidssfeer te schrijven is als lineaire combinatie van bolfuncties.Electrical Engineering, Mathematics and Computer ScienceDelft Institute of Applied Mathematic
A class of integral operators from Lebesgue spaces into harmonic Bergman-Besov or weighted Bloch spaces
No full textWe consider a class of two-parameter weighted integral operators induced by harmonic Bergman-Besov kernels on the unit ball of Rn and characterize precisely those that are bounded from Lebesgue spaces Lp? into harmonic Bergman-Besov spaces bq?, weighted Bloch spaces b?? or the space of bounded harmonic functions h?, allowing the exponents to be different. These operators can be viewed as generalizations of the harmonic Bergman-Besov projections. © 2021, Hacettepe University. All rights reserved
The Weighted Bergman Projection and Related Theory on the Minimal Ball
No full textAbstractIn this note we compute the weighted Bergman kernel of the unit ball with respect to the smallest norm in Cn that extends the euclidian norm in Rn. We establish the regularity properties of the corresponding weighted Bergman projection and give some applications
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