PURPOSE To investigate the effect of lag-screw positions in the femoral head on modes of fixation failure. METHODS 591 patients aged 65 years or older underwent sliding compression screw fixation for type A(1) (n=249) and type A(2) (n=342) intertrochanteric fractures of the femur after low-energy injuries. There were 18 cases of fixation failure; in 13 (group 1) the lag screw was placed in th...

The impact of market imperfections is tremendous. They influence not only the pricing of financial assets, but also the dynamic relationship among financial instruments. Hsu and Wang (2004) develop a pricing model of stock index futures in imperfect markets, providing a method for estimating the implied expected growth rate. By using the vector auto regression (VAR) model, Granger causality tes...

Identifying which outlet in social media leads the rest in disseminating novel information on specific topics is an interesting challenge for information analysts and social scientists. In this work, we hypothesize that novel ideas are disseminated through the creation and propagation of new or newly emphasized key words, and therefore lead/lag of outlets can be estimated by tracking word usage...

Current methods for the identification of putatively co-regulated genes directly from gene expression time profiles are based on the similarity of the time profile. Such association metrics, despite their central role in gene network inference and machine learning, have largely ignored the impact of dynamics or variation in mRNA stability. Here we introduce a simple, but powerful, new similarit...

The finite-sample size and power properties of bootstrapped likelihood ratio systems cointegration tests are investigated via Monte Carlo simulations when the true lag order of the data generating process is unknown. Recursive bootstrap schemes are employed which differ in the way the lag order is chosen. The order is estimated by minimizing different information criteria and by combining the c...