Immature oligodendrocytes (OLs) derive from a large pool of late OL progenitors that populate human cerebral white matter throughout the latter half of gestation. We recently reported that a minor population of immature OLs are present in human cerebral white matter for at least 3 months before these cells commit to myelinogenesis around 30 wk postconceptional age. Since this finding supports d...

While 2SLS is the most widely used estimator for simuhaneous equation models, OLS may do better in finite samples. Here we demonstrate analytically that the for the widely used simultaneous equation model with one jointly endogenous variable and valid instruments, 2SLS has smaller MSE error, up to second order, than OLS unless the R , or the F statistic of the reduced form equation is extremely...

An ordinary least squares (OLS) analysis of the relationship between chlorophyll a (chl a) concentrations and photosynthetic rates at depths of 5 and 25 m at Station ALOHA produced a slope that was only 28% of the mean productivity index at those depths and an intercept at zero chl a that equaled 70% of the mean photosynthetic rate. OLS regression lines are known to produce a slope and intercep...

Oral leukoplakia (OL) is the most common premalignancy in the oral cavity. A small proportion of OLs progresses to oral squamous cell carcinoma (OSCC). To assess OSCC risk of OLs, we investigated the role of the transcriptional repressor enhancer of zeste homolog 2 (EZH2) in oral tumorigenesis and its clinical implication as an OSCC risk predictor. Immunohistochemistry was used to measure EZH2 ...

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...

This note generalizes previous results on the asymptotic equivalence of Ordinary and Generalized Least Squares estimates in Linear Regression models with trending data. This note considers the relative e ciency of OLS versus GLS in the linear regression model yt = x 0 t + ut (t = 1 ;2; : : : ); (1) where xt and are K 1 and where the unobservable disturbances ut are autocorrelated but independen...

This note formalizes bias and inconsistency results for ordinary least squares (OLS) on the linear probability model and provides sufficient conditions for unbiasedness and consistency to hold. The conditions suggest that a btrimming estimatorQ may reduce OLS bias. D 2005 Elsevier B.V. All rights reserved.