The scalability and robustness of a class of non-overlapping domain decomposition preconditioners using 2-way nested dissection reordering is studied. In particular, three methods are considered: a nested symmetric successive over-relaxation (NSSOR), a nested version of modified ILU with rowsum constraint (NMILUR), and nested filtering factorization (NFF). The NMILUR preconditioner is exact wit...

Case-cohort and nested case-control designs are often used to select an appropriate subsample of individuals from prospective cohort studies. Despite the great attention that has been given to the calculation of association estimators, no formal methods have been described for estimating risk prediction measures from these 2 sampling designs. Using real data from the Swedish Twin Registry (2004...

In this work, we explore proof theoretical connections between sequent, nested and labelled calculi. In particular, we show a general algorithm for transforming a class of nested systems into sequent calculus systems, passing through linear nested systems. Moreover, we show a semantical characterisation of intuitionistic, multi-modal and non-normal modal logics for all these systems, via a case...

OBJECTIVE To calculate relative powers for nested case-control studies for different values of both relative risk and numbers of controls per case, given a fixed number of cases available for analysis. METHODS Algebraic and numerical methods. RESULTS In nested case-control studies, statistical power is a function of relative risk, rarity of exposure, number of case-control sets, and the num...

An important task in the application of Markov models to the analysis of ion channel data is the determination of the correct gating scheme of the ion channel under investigation. Some prior knowledge from other experiments can reduce significantly the number of possible models. If these models are standard statistical procedures nested like likelihood ratio testing, provide reliable selection ...

Researchers subject to time and budget constraints may conduct small nested case-control studies with individually matched controls to help optimize statistical power. In this paper, we show how precision can be improved considerably by combining data from a small nested case-control study with data from a larger nested case-control study of a different outcome in the same or overlapping cohort...

BACKGROUND Epidemiological studies of exposures that vary with time require an additional level of methodological complexity to account for the time-dependence of exposure. This study compares a nested case-control approach for the study of time-dependent exposure with cohort analysis using Cox regression including time-dependent covariates. METHODS A cohort of 1340 subjects with four fixed a...