Curve walking of crayfish Astacus leptodactylus was investigated by exploiting their optomotor response. The animal walked while spatially fixed on a motor-driven treadmill and turning behaviour was induced by an optical stimulus, a pattern consisting of vertical stripes moving in a horizontal direction. In this open-loop situation, the crayfish maintains the same step frequency for the legs on...

An image processing system was programmed to automatically track and digitize the movement of amebae under phase-contrast microscopy. The amebae moved in a novel chemotaxis chamber designed to provide stable linear attractant gradients in a thin agarose gel. The gradients were established by pumping attractant and buffer solutions through semipermeable hollow fibers embedded in the agarose gel....

To understand shapes and movements of cells undergoing lamellipodial motility, we systematically explore minimal free-boundary models of actin-myosin contractility consisting of the force-balance and myosin transport equations. The models account for isotropic contraction proportional to myosin density, viscous stresses in the actin network, and constant-strength viscous-like adhesion. The cont...

Chemotaxis of spermatozoa to female gonophores has been shown to occur in Campanularia, Tubularia and other hydroids (Miller, 1966 a, b). Cinemicrographic records of the movements of Campanularia spermatozoa in the vicinity of female gonophores or of glass capillary pipettes containing extracts of female hydranths have shown that chemotactic aggregation of the spermatozoa occurs because the spe...

With the increased requirement of miniaturization structures on hard and brittle substrates, micro abrasive air jet turning technology has become a promising machining for manufacturing structures. This paper presents an investigation multi-pass radial-mode fused silica. The effect parameters depth cut materials removal rate was analyzed. waviness striation formation mechanisms were studied. It...

Road traffic accidents are the leading cause of death in international travelers. With the growth of international travel, the number of visitors who rent a vehicle upon arrival at their destination by air or by sea is expected to increase. Jet lag is a well-recognized maladaptation to international travel across multiple time zones. Little is known about the possible influence of jet lag sympt...

in this research, the frequency of the jet streams associated with extreme and pervasive precipitation has been analyzed using environmental to circulation approach. based on the 99th percentile index, 109 days of the extreme and pervasive precipitation was selected from the irimo data base ( including 33 synoptic, climatic and rain gage stations during 15992 days from farvardin, 1st, 1340 to d...

numerous investigations have been devoted towards understanding the hydrodynamics of gas jets in fluidized beds. however, most of them address the problem from  macroscopic point of view, which does not reveal the true behavior in the jet region at the single particle level. the present work aims to understand the jet behavior from a more fundamental level, i.e. the individual particle level. a...

Substantial progress achieved during the past decade in studies of active galactic nuclei (see [25] for a review of recent results) has brought an increasingly wider recognition of the ubiquity of relativistic outflows (jets) in galactic nuclei [5, 43] turning them into an effective probe of nuclear regions in galaxies [21]. Emission properties, dynamics, and evolution of an extragalactic jet a...