It is more common for educational and psychological data to be non-normal than to be approximately normal. This tendency may lead to bias and error in point estimates of the Pearson correlation coefficient. In a series of Monte Carlo simulations, the Pearson correlation was examined under conditions of normal and non-normal data, and it was compared to its major alternatives, including the Spea...

INTRODUCTION liver disease resulting from chronic hepatitis C virus (HCV) infection follows an asymptomatic course towards cirrhosis and its complications in 20-40% of cases. Earlier studies demonstrated that advanced fibrosis is a prognostic factor. The "gold standard" for the evaluation of fibrosis grade is liver biopsy. Our group validated a predictive index - NIHCED - based on demographic, ...

OBJECTIVE To evaluate the accuracy of the Depression Subscale of Hospital Anxiety and Depression Scale (HADS-D) in spine surgery, comparing it to Beck Depression Inventory (BDI). METHODS In a cross-sectional study, the HADS-D and the BDI were applied to patients undergoing spine surgery for lumbar (n=139) or cervical spondylosis (n=17). Spearman correlation tests for HADS-D and BDI were appli...

Using an automated data processing algorithm, we examined electric field records of 5498 negative cloud-to-ground flashes reported by the U.S. National Lightning Detection Network (NLDN) within 50 to 500 km of the Lightning Observatory in Gainesville (LOG), Florida. Out of the 5498 flashes, 3496 (64%) had detectable preliminary breakdown (PB) pulse trains. Only 3077 flashes with a single PB pul...

We developed and tested the clinimetric properties of a scale for psychogenic movement disorders (PMDs). PMDs are disabling but lack any generally accepted treatment strategies. To develop treatments, means of assessing disease severity must be provided. No scale to assess PMDs existed. The PMD scale developed here rates 10 phenomena (rest tremor, action tremor, dystonia, chorea, bradykinesia, ...

Adhesion molecules, which play a major role in lymphocyte circulation, have not been well characterized in human immunodeficiency virus (HIV) infection. T-lymphocyte populations, including CD3, CD4, CD28, and adhesion molecules (L selectin, LFA-1, VLA-4, and ICAM-1) were measured by flow cytometry in a cross-sectional study of 100 HIV-infected and 49 HIV-seronegative adults. HIV-infected adults...

BACKGROUND AND PURPOSE The clinical course of stroke due to occlusion of the internal carotid artery is influenced by amount of collateral flow. We measured mean frequency shifts in the middle cerebral artery by transcranial Doppler ultrasonography to determine its prognostic value. METHODS Patients with proven extracranial occlusion of the internal carotid artery and ipsilateral hemispheral ...

PURPOSE To assess the arterial stiffness in patients with branch retinal vein occlusion (BRVO). METHODS Brachial-ankle pulse wave velocity (PWV) and ankle-brachial index were measured in 10 patients with BRVO (mean age 67.9 +/- 7.5 years) and in 18 age-matched controls (mean age 66.9 +/- 6.8 years). The controls were subjects with systemic essential hypertension having no retinal lesions. R...