In linear regression with heteroscedastic errors, the Generalized Least Squares (GLS) estimator is optimal, i.e., it is the Best Linear Unbiased Estimator (BLUE). The Ordinary Least Squares (OLS) estimator is suboptimal but still valid, i.e., unbiased and consistent. Halbert White, in his seminal paper (Econometrica, 1980) used the OLS residuals in order to obtain an estimate of the standard er...

Oligodendrocytes (OLs) extend processes to contact axons as a prerequisite step in myelin formation. As the OL processes migrate toward their axonal targets, they modify adhesion to their substrate, an event that may be regulated by matrix metalloproteinases (MMPs). In the mouse optic nerve, MMP-9/gelatinase B increases during myelin formation. Although tissue inhibitor of metalloproteinase (TI...

Proanthocyanidins (PAs) are common polyphenolic polymers of plants found in foliage, fruit, bark, roots, rhizomes, and seed coats that consist of flavan-3-ol units such as 2,3-trans-(+)-catechin and 2,3-cis-(-)-epicatechin. Although the biosynthesis of flavan-3-ols has been studied in angiosperms, little is known about their biosynthesis and ecological roles in gymnosperms. In this study, the g...

Moser, Sydney Elizabeth. M.S., Purdue University, December 2013. The Effect of Individual Milk Proteins on Stability of Green Tea Flavan-3-ols. Major Professor: Mario G. Ferruzzi. While information regarding the impact of flavan-3-ol-protein interactions on food quality attributes (flavor, texture, and physical stability) exists, insight into the potential consequence of these interactions on b...

HAC estimators are known to produce test statistics that reject too frequently in finite samples. One neglected reason comes from using the OLS residuals when constructing the HAC estimator. If the regression matrix contains high leverage points, such as from outliers, then the OLS residuals will be negatively biased. This reduces the variance of the OLS residuals and the HAC estimator takes th...

Developing oligodendrocytes (OLs) are highly vulnerable to glutamate excitotoxicity. Although OL excitotoxicity is mainly mediated by alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptors (AMPARs) and is Ca2+-dependent, the molecular basis for AMPAR-mediated Ca2+ influx in OLs remains largely unclear. Ca2+ permeability of AMPARs is inversely correlated with the abundance of the...

This paper compares ordinary least squares (OLS), weighted least squares (WLS), and adaptive least squares (ALS) by means of a Monte Carlo study and an application to two empirical data sets. Overall, ALS emerges as the winner: It achieves most or even all of the efficiency gains of WLS over OLS when WLS outperforms OLS, but it only has very limited downside risk compared to OLS when OLS outper...

M yelin is the membranous structure that wraps around axonal segments and supports the fast saltatory conduction of action potentials along axons (1, 2). Disorders that disrupt myelin during development or in adulthood, such as multiple sclerosis, lead to severe pathologies, illustrating myelin’s crucial role in normal neural functioning. In the central nervous system, oligodendrocytes (OLs) ar...

An efficient palladium-catalyzed asymmetric hydrogenation of fluorinated aromatic pyrazol-5-ols has been developed via capture of the active tautomers. A wide variety of 2,5-disubstituted and 2,4,5-trisubstituted pyrazolidinones have been synthesized with up to 96% and 95% ee, respectively. The hydrogenation pathway includes Brønsted acid promoted tautomerization of pyrazol-5-ols and Pd-catalyz...