African mormyrids, such as Gnathonemus petersii, migrate: nocturnally, from daytime shelters to find food and return by morning, and seasonally, spawning in swamps flooded during the rainy season. The present study examined whether the fish use landmarks detected via electrolocation to locate an aperture, whether they detect changes in landmark size and respond appropriately, whether landmarks ...

from a single spot on the sample surface. Depending on the homogeneity of the sample, the small spot size sampled with the tightly focused laser beam may miss the target material completely. A larger laser beam and sampling aperture can be used to acquire data from a larger spot on the sample surface, but as the aperture size is increased, resolution decreases and the high spectral resolution n...

Many high-energy lasers (HELs) have noncircular output apertures. Some are rectangular in shape with or without a central or noncentral (up to 30%) obscuration. However, most high-energy laser propagation codes (especially those developed for systems analysis) model the aperture as either an unobscured circle or as a circle with fixed (e.g., 10%) obscuration. We present a beam-quality/aperture-...

We investigated the interaction between extra-retinal rotation signals and retinal motion signals in heading perception during pursuit eye movement. For limited viewing aperture, the variability in perceived heading strongly depends on the pattern of motion directions. Heading towards a point outside the aperture generates nearly parallel aperture flow. This results in lower precision of percei...

The purpose of this study is to determine visual performance in water, including the influence of pupil size. The water environment was simulated by placing goggles filled with saline in front of the eyes with apertures placed at the front of the goggles. Correction factors were determined for the different magnification under this condition in order to estimate vision in water. Experiments wer...

Squid are the largest jet propellers in nature as adults, but as paralarvae they are some of the smallest, faced with the inherent inefficiency of jet propulsion at a low Reynolds number. In this study we describe the behavior and kinematics of locomotion in 1 mm paralarvae of Dosidicus gigas, the smallest squid yet studied. They swim with hop-and-sink behavior and can engage in fast jets by re...

We report on a pixel whose aperture can be varied electrically. The pixel is confined by a hole-patterned polymer wall and a dielectric liquid forms a ring shape around the wall surface. Without an electric field, the pixel has the largest aperture. The applied fringing field stretches the liquid surface, leading to a decrease in the aperture size. The switchable aperture ratio of the pixel is ...

The finite depth of field of a real camera can be used to estimate the depth structure of a scene. While the distance of an object from the plane in focus determines the defocus blur size, the shape of the aperture determines the shape of the blur. This blur shape can be manipulated by introducing masks into the main lens aperture. We propose an intuitive criterion to design aperture patterns f...

In just three years since its first introduction,',' the oxide-confined VCSEL has come to dominate much of the semiconductor laser research e f f ~ r t . ~ ~ Its prominence in studies of semiconductor microcavity physics is expected to increase as well, as it represents a promising means of minimizing an optical mode volume. The ease of processing allows novel forms of two-dimensional arrays, a...

Passive imaging using millimeter waves (mmWs) has many advantages and applications in the defense and security markets. All terrestrial bodies emit mmW radiation and these wavelengths are able to penetrate smoke, blowing dust or sand, fog/clouds/marine layers, and even clothing. One primary obstacle to imaging in this spectrum is that longer wavelengths require larger apertures to achieve the r...