The Grid Location Service (GLS) is a location service which provides location information for a node in a mobile ad hoc network. GLS provides a mechanism for a node to track the location of other nodes in the network topology. A mobile ad hoc network (MANET) is an autonomous system of mobile routers (and associated hosts) connected by wireless links–the union of which form an arbitrary graph. T...

BACKGROUND Left ventricular (LV) systolic dysfunction is an important predictor of cardiovascular death. Global longitudinal strain (GLS) is a widely available echocardiographic technique proven to be more sensitive than conventional ejection fraction (EF) in detecting subtle changes in LV function. However, the prognostic value of GLS in patients with chronic kidney disease (CKD) is unknown. ...

Instrumental variable (IV) estimation typically requires the user to correctly specify the relationship between the regressors and the outcome to obtain a consistent estimate of the effects of the treatments. This paper proposes doubly robust IV regression estimators that only require the user to either correctly specify the relationship between the measured confounding variables (i.e., include...

The receiver operating characteristics (ROC) curve is a standard statistical tool to characterize the accuracy of diagnostic tests when test results are continuous. It provides a complete description of test performance and a meaningful way to compare the performances of different tests. The empirical (nonparametric) ROC curve is the most popular estimator of the ROC curve. Semiparametric estim...

BACKGROUND Patients with recovery of left ventricular ejection fraction (LVEF) remain at risk for future deterioration of LVEF. However, there are no tools to risk stratify these patients. We hypothesized that global longitudinal strain (GLS) could predict sustained recovery within this population. METHODS AND RESULTS We retrospectively identified 96 patients with a reduced LVEF <50% (screeni...

We provide an argument that (6) of the main paper is an unbiased estiamting function for ξ when the coarsening probabilities may not be correctly specified, so that the posited probabilities π{r, Gr(Z)} 6 = π0{r, Gr(Z)} for some r = 1, . . . ,M,∞, but the models hr{Gz(Z), ξ} are correct, and that estimators for ξ based on (6) will converge in probability to ξ0 for arbitrary choice of the functi...

This paper derives the limiting distributions of alternative jackknife IV (JIV ) estimators and gives formulae for accompanying consistent standard errors in the presence of heteroskedasticity and many instruments. The asymptotic framework includes the many instrument sequence of Bekker (1994) and the many weak instrument sequence of Chao and Swanson (2005). We show that JIV estimators are asym...

Background Arterial stiffness increases pressure load to the left ventricle (LV), leading to LV hypertrophy and subendocardial ischemia. Neurohormones stimulate myocardial fibrosis and LV dysfunction. We aimed to explore the associations of arterial stiffness and plasma aldosterone with multi-directional, layer-specific LV, and left atrial (LA) mechanical function in hypertensive patients. Me...

We consider fully modified least squares estimation for systems of cointegrating polynomial regressions, i. e., regressions that include deterministic variables, integrated processes and their powers as regressors. The errors are allowed to be correlated across equations, over time with the Whilst, course, OLS GLS coincide – any regular weighting matrix without restrictions on parameters same r...

We propose a general estimation principle based on the assumption that instrumental variables (IV) do not explain the error term in a structural equation. The estimators based on this principle is independent of the normalization constraint, unlike the standard IV estimators such as the two-stage least squares estimator. Using the new principle, we propose the L1 IV estimator, which is an IV es...