We have examined fractal patterns formed by the injection of air into oil in a thin (0.127 mm) layer contained between two cylindrical glass plates of 288 mm diameter (a Hele-Shaw cell), for pressure differences in the range 0.25 < or = DeltaP < or = 1.75 atm. We find that an asymptotic structure is reached at large values of the ratio r/b, where r is the pattern radius and b the gap between th...

The temperature responses of photosynthesis (A) and growth were examined in rice and wheat grown hydroponically under day/night temperature regimes of 13/10, 19/16, 25/19, 30/24 and 37/31 degrees C. Irrespective of growth temperature, the maximal rates of A were found to be at 30-35 degrees C in rice and at 25-30 degrees C in wheat. Below 25 degrees C the rates were higher in wheat, while above...

The effects of ozone at different concentrations (10, 30, 45 g/m3) on fluidity and thermotropic properties of erythrocyte membranes were investigated by EPR using two spin probes: 5-doxylstearic acid (5-DSA) and 16-doxylstearic acid (16-DSA). The effect of ozone on the erythrocyte membrane fluidity was a dose-dependent process. The ozone at concentration of 10 g/m3 caused rigidization of the me...

Many ectotherms regularly experience considerable short-term variations in environmental temperature, which affects their body temperature. Here we investigate the cardiovascular responses to a stepwise acute temperature increase from 10 to 13 and 16 degrees C in rainbow trout (Oncorhynchus mykiss). Cardiac output increased by 20 and 31% at 13 and 16 degrees C, respectively. This increase was e...

A short recovery period between same-day competitions is common practice in organized youth sports. We hypothesized that young athletes will experience an increase in physiological strain and perceptual discomfort during a second identical exercise bout in the heat, with 1 h (21 degrees C) between bouts, even with ample hydration. Twenty-four athletes (6 boys and 6 girls: 12-13 yr old, 47.7 +/-...

BACKGROUND AND PURPOSE Hypothermia to core temperatures ranging from 16 degrees C to 24 degrees C has become an established procedure to extend the "safe" interval of cardiac arrest during open heart surgery in human infants. The present experiment was designed to ascertain whether differences in core (rectal) temperature during hypothermic circulatory arrest influence the presence and extent o...

OBJECTIVES To define the effects of annuloplasty rings (ARs) on the dynamic motion of anterior mitral leaflet (AML) and posterior mitral leaflet (PML). METHODS Fifty-eight adult, Dorsett-hybrid, male sheep (49 + or - 5 kg) had radiopaque markers inserted: eight around the mitral annulus, four along the central meridian (from edge to annulus) of the AML (#A(1)-#A(4)) and one on the PML edge (#...

1. The rate of pulsation of the anterior contractile vacuole of Paramecium caudatum under chloretone anesthesia has been determined over a range of temperatures from 9-31 degrees C. It has been found that the rate is a logarithmic function of the temperature according to the Arrhenius equation. From 9-16 degrees the temperature characteristic (micro) has the value 25,600; from 16-22 degrees it ...