Changes of annulus luminance in traditional disk-and-annulus patterns can be perceived to be either reflectance or illuminance changes. In the present experiments, we examined the effect of varying annulus reflectance. In Experiment 1, we placed test and standard patch-and-surround patterns in identical Mondrian patchworks. Only the luminance of the test surround changed from trial to trial, ap...

OBJECTIVE To study the time course and underlying mechanisms of right heart filling after cardiac surgery. DESIGN A prospective observational study of adult patients undergoing cardiac surgery. SETTING Echocardiography laboratory of the Stanford University Medical Center. PATIENTS Twenty six patients (mean age 54.9) undergoing cardiac surgery were studied before and two days, one week, si...

Objective: To evaluate long term results and independent predictors of outcome of aortic valvoplasty. Design: Retrospective follow up study. Independent predictors of outcome identified by multiple logistic regression. Setting: Tertiary referral centre. Patients: 269 consecutive patients treated at the median age of 8 months (0–23 years): 80 (30%) under 4 weeks, 59 (22%) between 4 weeks and 1 y...

OBJECTIVE To evaluate long term results and independent predictors of outcome of aortic valvoplasty. DESIGN Retrospective follow up study. Independent predictors of outcome identified by multiple logistic regression. SETTING Tertiary referral centre. PATIENTS 269 consecutive patients treated at the median age of 8 months (0-23 years): 80 (30%) under 4 weeks, 59 (22%) between 4 weeks and 1...

Chronic heart disease contributes to the mortality of patients with AIDS. Although studies of left ventricular function in patients with acquired immune deficiency syndrome (AIDS) have been conducted, studies of right ventricular function are rare. The present study aimed to characterize the tricuspid annulus movement and evaluate the right ventricular function of patients with AIDS by tissue D...

Let W be a weight–homogeneous planar polynomial differential system with a center. We find an upper bound of the number of limit cycles which bifurcate from the period annulus of W under a generic polynomial perturbation. We apply this result to a particular family of planar polynomial systems having a nilpotent center without meromorphic first integral. 2000 AMS Subject Classification: 34C07, ...

For a family of two-dimensional predator–prey models Gause type, we investigate the simultaneous occurrence center singularity and limit cycle. The is characterized by fact that functional response nonanalytical exhibits group defense. We prove existence uniqueness cycle using new theorem for Liénard systems. gives conditions which surrounds period annulus. results this paper provide mechanism ...

Let W be a weight–homogeneous planar polynomial differential system with a center. We find an upper bound of the number of limit cycles which bifurcate from the period annulus of W under a generic polynomial perturbation. We apply this result to a particular family of planar polynomial systems having a nilpotent center without meromorphic first integral. 2000 AMS Subject Classification: 34C07, ...

BACKGROUND The annulus is a ring-shaped structure located beneath the plasma membrane that connects the midpiece and the principal piece of mammalian sperm flagellum. It has been suggested that the annulus acts as a morphological organizer, guiding flagellum assembly during spermiogenesis, and as a diffusion barrier, confining proteins to distinct compartments of the flagellum in mature sperm. ...