Confinement of living microorganisms and self-propelled particles by an external trap provides a means of analysing the motion and behaviour of active systems. Developing a tweezer with a trapping radius large compared with the swimmers' size and run length has been an experimental challenge, as standard optical traps are too weak. Here we report the novel use of an acoustic tweezer to confine ...

Six experiments investigated 7-month-old infants’ capacity to learn about the self-propelled motion of an object. After observing 1 wind-up toy animal move on its own and a second wind-up toy animal move passively by an experimenter’s hand, infants looked reliably longer at the former object during a subsequent stationary test, providing evidence that infants learned and remembered the mapping ...

Direct numerical simulation is used to simulate the turbulent wake behind an accelerating axisymmetric self-propelled body in a stratified fluid. Acceleration is modelled by adding a velocity profile corresponding to net thrust to a self-propelled velocity profile resulting in a wake with excess momentum. The effect of a small to moderate amount of excess momentum on the initially momentumless ...

objective: microleakage in the gingival floor of class ii composite restorations can compromise the marginal adaptation of the filling material to the cavity edges. the aim of this study was to evaluate the effect of light conducting cylindrical inserts in decreasing the microleakage of the gingival floor in cavities 1mm below the cej. materials and methods: eighty maxillary first molars were r...

Swarms of self-propelled particles exhibit complex behavior that can arise from simple models, with large changes in swarm behavior resulting from small changes in model parameters. We investigate the steady-state swarms formed by self-propelled Morse particles in three dimensions using molecular dynamics simulations optimized for graphics processing units. We find a variety of swarms of differ...

The associative learning account of how infants identify human motion rests on the assumption that this knowledge is derived from statistical regularities seen in the world. Yet, no catalog exists of what visual input infants receive of human motion, and of causal and self-propelled motion in particular. In this manuscript, we demonstrate that the frequency with which causal agency and self-pro...

OBJECTIVES To compare the noise and vibration levels associated with three hand-held rock drills (pneumatic, hydraulic and electric) currently used in South African mines, and a prototype acoustically shielded self-propelled rock drill. METHODS Equivalent A-weighted sound pressure levels were recorded on a geometrical grid, using Rion NL-11 and NL-14 sound level meters. Vibration measurements...

insert ← 1 some preprocessing to use algorithm for (i ← 1; i ≤ n; i ← i + 1) rearrange columns to put matrix in usable form for (j ← 1; j ≤ m; j ← j + 1) sorts columns by source node if (N [i, j] = 1) N ← swapcol(N, j, insert) insert ← insert + 1 top ← 1 now sorts by destination node for arcs with same source insert ← 1 while (top ≤ n) for (i ← 1; i ≤ n; i ← i + 1) for (j ← 1; j ≤ m; j ← j + 1)...

Electrical screed levelling machines are developed to reduce kneeling and trunk flexion of sand-cement-bound screed floor layers. An observational intervention study among 10 floor layers was performed to assess the differences between a self-propelled and a manually moved machine. The outcome measures were work demands, production time, perceived load, discomfort and applicability. Compared to...