Plants sense positional changes relative to the gravity vector. To date, the signaling processes by which the perception of a gravistimulus is linked to the initiation of differential growth are poorly defined. We have investigated the role of inositol 1,4,5-trisphosphate (InsP(3)) in the gravitropic response of oat (Avena sativa) shoot pulvini. Within 15 s of gravistimulation, InsP(3) levels i...

Positional behavior is the measurable and observable link between the biology and behavior of an animal in its environment. In this dissertation, I examine ontogenetic patterns of positional behavior in infant, juvenile, and adult white-faced capuchins (Cebus capucinus) and mantled howling monkeys (Alouatta palliata) inhabiting the same tropical forest in Costa Rica. During growth and developme...

benign paroxysmal positional vertigo (bppv) is a condition that indicates a benign inner ear disorder. it is generally believed that bppv is due to the dislodged otoconial particles from otolith organs and unusual collection of them within any of semicircular canals or even in all three semicircular canals. although the typical features of nystagmus in bppv have been well-studied, very few stud...

Current models of pattern formation in Hydra propose head-and foot-specific morphogens to control the development of the body ends and along the body length axis. In addition, these morphogens are proposed to control a cellular parameter (positional value, source density) which changes gradually along the axis. This gradient determines the tissue polarity and the regional capacity to form a hea...

INTRODUCTION Unilateral or bilateral dilation of the ureters occurs commonly during pregnancy. Ultrasonography is a suitable diagnostic method for hydronephrosis; however, it cannot differentiate obstructive from nonobstructive hydronephrosis. Our aim was to evaluate measurable changes in hydronephrosis induced by a mother's positional changes using ultrasonography to differentiate hydronephros...

This study consists of a general review of benign paroxysmal positional vertigo and nystagmus. The main etiopathogenesis, diagnosis, and treatments are evoked. The author describes his experience on the subject.