In this paper, we present a single actuator wave-like robot, a novel bioinspired robot which can move forward or backward by producing a continuously advancing wave. The robot has a unique minimalistic mechanical design and produces an advancing sine wave, with a large amplitude, using only a single motor but with no internal straight spine. Over horizontal surfaces, the robot does not slide relative to the surface and its direction of locomotion is determined by the direction of rotation of the motor. We developed a kinematic model of the robot that accounts for the two-dimensional mechanics of motion and yields the speed of the links relative to the motor. Based on the optimization of the kinematic model, and accounting for the mechanical constraints, we have designed and built multiple versions of the robot with different sizes and experimentally tested them (see movie). The experimental results were within a few percentages of the expectations. The larger version attained a top speed of 57 cm s(-1) over a horizontal surface and is capable of climbing vertically when placed between two walls. By optimizing the parameters, we succeeded in making the robot travel by 13% faster than its own wave speed.

Calcium is an important element in animal and plant tissues, but nothing is known with regard to the fractionation of its stable isotopes in biological systems. In this work the results of calcium isotope fractionation in date palms are reported. The palm is a dioecious tree, and thus its pollen is easily collected. A comparison was made between leaves and pollen from two trees that are approximately 70 km apart, growing in different geographical locations. Fruit pulp and seeds from the same fruit were also compared. The results of this work imply preferential depletion of the heavy calcium isotopes in tissues associated with reproduction.

Abstract— The production of UV‐induced thymine dimers and their fate upon post‐irradiation incubation in the dark was studied in DNA of the intact water plants Wolffia microscopica and Spirodela polyrhiza. The results demonstrate production of thymine dimers, and the ability of the plant cells to remove the dimers from their DNA. The rate of removal is rapid during the first few h of post‐irradiation incubation in the dark. It continues at a slower rate for the next 24–48 h, at which time it is essentially complete. The disappearance of thymine dimers in light or in the dark is analogous to the well‐known processes in other biological systems, namely, photoreactivation and dark excision.

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