It is shown that the basic regularization procedures for finding meaningful approximate solutions of ill-conditioned or singular linear systems can be phrased and analyzed in terms of classical linear algebra that can be taught in any numerical analysis course. Apart from rewriting many known results in a more elegant form, we also derive a new two-parameter family of merit functions for the de...

Generalized Cross Validation (GCV) is a popular approach to determining the regularization parameter in Tikhonov regularization. The regularization parameter is chosen by minimizing an expression, which is easy to evaluate for small-scale problems, but prohibitively expensive to compute for large-scale ones. This paper describes a novel method, based on Gauss-type quadrature, for determining up...

In this paper penalized weighted least-squares is used to jointly estimate nonparametric functions from contemporaneously correlated data. Under conditions generally encountered in practice, it is shown that these joint estimates have smaller posterior variances than those of marginal estimates and are therefore more efficient. We describe three methods: generalized maximum likelihood (GML), ge...

Gaussian processes are powerful regression models specified by parameterized mean and covariance functions. Standard approaches to choose these parameters (known by the name hyperparameters) are maximum likelihood and maximum a posteriori. In this article, we propose and investigate predictive approaches based on Geisser's predictive sample reuse (PSR) methodology and the related Stone's cross-...

Recent work by Reiss and Ogden (2009) provides a theoretical basis for sometimes preferring restricted maximum likelihood (REML) to generalized cross validation (GCV) for smoothing parameter selection in semiparametric regression. However, existing REML or marginal likelihood (ML) based methods for semiparametric GLMs use iterative REML/ML estimation of the smoothing parameters of working linea...

Human cytomegalovirus (HCMV) is a widespread pathogen that can cause severe disease in immunologically immature and immunocompromised patients. The current standard of therapy for the treatment of HCMV infections is ganciclovir (GCV). However, high incidence rates of adverse effects are prevalent and limit the use of this drug. Cyclopropavir (CPV) is 10-fold more effective against HCMV in vitro...

PURPOSE The purpose of this study was to investigate the effect of the antiviral drug ganciclovir (GCV) on Müller glia dedifferentiation and proliferation and the underlying cellular and molecular mechanisms in adult zebrafish. METHODS A Tg(1016tuba1a:GFP) transgenic line was generated to identify injury-induced dedifferentiation of Müller glia. Mechanical retinal damage was induced by a need...

PURPOSE To evaluate the intraocular safety and antiviral treatment efficacy of the sustained lipid prodrug of ganciclovir, 1-O-hexadecylpropanediol-3-phospho-ganciclovir (HDP-P-GCV), as an intravitreal injectable drug system for viral retinitis. METHODS HDP-P-GCV was synthesized by coupling 1-O-hexadecyl-propanediol-3-phosphate to either free hydroxyl of ganciclovir in pyridine with dicyclohe...

PURPOSE To evaluate the efficacy of a biodegradable scleral plug containing ganciclovir (GCV) in a rabbit model of human cytomegalovirus (HCMV) retinitis. METHODS To develop a rabbit model for HCMV retinitis, HCMV solution was injected once into the vitreous cavity of pigmented rabbits. The treated animals were divided into three groups: group A received no treatment, group B was treated once...

A study was carried out in mungbean Vigna radiata (L.) Wilczek) with eight ‘lines’ and four ‘testers’ crossed in a Line x Tester Genetic variability, heritability and genetic advance were estimated for marketable and its component yield traits in 48 lines of carrot (Daucus carota var. sativa L.). The study showed high ranges for total yield (3.15 -7.56 kg/plot), marketable yield (2.60 – 6.85 kg...