OBJECTIVES This study sought to evaluate myocardial contraction fraction (MCF) as an index of myocardial shortening by comparison to conventional shortening indices in patients with hypertensive hypertrophy, athletes with physiologic hypertrophy and sedentary normal adult subjects. BACKGROUND A significant percentage of patients with hypertensive hypertrophy have "normal" or "preserved" left ...

One of the main obstacles in quantitative interpretation of functional magnetic resonance imaging (fMRI) signal is that this signal is influenced by non-neural factors such as vascular properties of the brain, which effectively increases signal variability. One approach to account for non-neural components is to identify and measure these confounding factors and to include them as covariates in...

In this experiment we explored age differences in frequency judgment. Young and older adults studied words occurring from one to six times under divided or focused attention and then completed either a frequency discrimination or a frequency estimation test for these items. Divided attention led to poorer performance on both frequency judgment tests, suggesting that distraction during the encod...

Age differences in emotional experience, expression, and control were investigated in 4 studies. A community sample of 127 African Americans and European Americans (ages 19-96 years) was used in Study 1; a community sample of 82 Chinese Americans and European Americans (ages 20-85 years) was used in Study 2; a community sample of 49 Norwegians drawn from 2 age groups (ages 20-35 years and 70+ y...

Three experiments are reported on implicit learning in 432 children between the ages of 4 and 10 years, using a new paradigm ("the neutral parameter procedure") based on drawing behavior. The first two experiments demonstrated that children modified their drawing behavior following specially devised practice in such a way that these modifications could not be viewed as the result of deliberate ...

Previous research has suggested that an age-related decline in change detection may be due to older adults using a more conservative response criterion. However, this finding may reflect methodological limitations of the traditional change detection design, in which displays are presented continuously until a change is detected. Across 2 experiments, the authors assessed adult age differences i...

ceeds supply.@ Adenosine measurement is difficult in any given circumstance, as elements such as endothe hal cell and blood uptake and release, interstitial concentration, intracellular binding with SAH-hydro lase, and flow all influence venous adenosine concen trations. Adenosine is removed from tissues either by phos phorylation to AMP by adenosine kinase or by deam ination by adenosine deami...

Root resorption is a physiologic event for the primary teeth. It is still unclear whether odontoclasts, the cells which resorb the dental hard tissue, are different from the osteoclasts, the cells that resorb bone. Root resorption seems to be initiated and regulated by the stellate reticulum and the dental follicle of the underlying permanent tooth via the secretion of stimulatory molecules, i....