Simple mechanisms organise orientation of escape swimming in embryos and hatchling tadpoles of Xenopus laevis

2000 ◽  
Vol 203 (12) ◽  
pp. 1869-1885 ◽  
Author(s):  
A. Roberts ◽  
N.A. Hill ◽  
R. Hicks
Keyword(s):  
Mathematical Model ◽  
Xenopus Laevis ◽  
High Speed ◽  
Three Dimensional ◽  
Longitudinal Axis ◽  
The Body ◽  
Video Recordings ◽  
Stage Of Development ◽  
Physical Features ◽  
Neutrally Buoyant

Many amphibian tadpoles hatch and swim before their inner ears and sense of spatial orientation differentiate. We describe upward and downward swimming responses in hatchling Xenopus laevis tadpoles from stages 32 to 37/38 in which the body rotates about its longitudinal axis. Tadpoles are heavier than water and, if touched while lying on the substratum, they reliably swim upwards, often in a tight spiral. This response has been observed using stroboscopic photography and high-speed video recordings. The sense of the spiral is not fixed for individual tadpoles. In ‘more horizontal swimming’ (i.e. in directions within +/−30 degrees of the horizontal), the tadpoles usually swim belly-down, but this position is not a prerequisite for subsequent upward spiral swimming. Newly hatched tadpoles spend 99 % of their time hanging tail-down from mucus secreted by a cement gland on the head. When suspended in mid-water by a mucus strand, tadpoles from stage 31 to 37/38 tend to swim spirally down when touched on the head and up when touched on the tail. The three-dimensional swimming paths of stage 33/34 tadpoles were plotted using simultaneous video images recorded from the side and from above. Tadpoles spiralled for 70 % of the swimming time, and the probability of spiralling increased to 1 as swim path angles became more vertical. Tadpoles were neutrally buoyant in Percoll/water mixtures at 1.05 g cm(−)(3), in which anaesthetised tadpoles floated belly-down and head-up at 30 degrees. In water, their centre of mass was ventral to the muscles in the yolk mass. A simple mathematical model suggests that the orientation of tadpoles during swimming is governed by the action of two torques, one of which raises the head (i.e. increases the pitch) and the other rotates (rolls) the body. Consequently, tadpoles (i) swim belly-down when the body is approximately horizontal because the body is ballasted by dense yolk, and (ii) swim spirally at more vertical orientations when the ballasting no longer stabilises orientation. Measurements in tethered tadpoles show that dorsal body flexion, which could produce a dorsal pitch torque, is present during swimming and increases with tailbeat frequency. We discuss how much of the tadpole's behaviour can be explained by our mathematical model and suggest that, at this stage of development, oriented swimming responses may depend on simple touch reflexes, the organisation of the muscles and physical features of the body, rather than on vestibular reflexes.

scholarly journals A faster escape does not enhance survival in zebrafish larvae

2017 ◽  
Vol 284 (1852) ◽  
pp. 20170359 ◽  
Author(s):  
Arjun Nair ◽  
Christy Nguyen ◽  
Matthew J. McHenry
Keyword(s):  
High Speed ◽  
Larval Fish ◽  
Body Position ◽  
Three Dimensional ◽  
Limited Range ◽  
The Body ◽  
Model Parameters ◽  
Fish Prey ◽  
Zebrafish Larvae ◽  
Fish Predators

An escape response is a rapid manoeuvre used by prey to evade predators. Performing this manoeuvre at greater speed, in a favourable direction, or from a longer distance have been hypothesized to enhance the survival of prey, but these ideas are difficult to test experimentally. We examined how prey survival depends on escape kinematics through a novel combination of experimentation and mathematical modelling. This approach focused on zebrafish ( Danio rerio ) larvae under predation by adults and juveniles of the same species. High-speed three-dimensional kinematics were used to track the body position of prey and predator and to determine the probability of behavioural actions by both fish. These measurements provided the basis for an agent-based probabilistic model that simulated the trajectories of the animals. Predictions of survivorship by this model were found by Monte Carlo simulations to agree with our observations and we examined how these predictions varied by changing individual model parameters. Contrary to expectation, we found that survival may not be improved by increasing the speed or altering the direction of the escape. Rather, zebrafish larvae operate with sufficiently high locomotor performance due to the relatively slow approach and limited range of suction feeding by fish predators. We did find that survival was enhanced when prey responded from a greater distance. This is an ability that depends on the capacity of the visual and lateral line systems to detect a looming threat. Therefore, performance in sensing, and not locomotion, is decisive for improving the survival of larval fish prey. These results offer a framework for understanding the evolution of predator–prey strategy that may inform prey survival in a broad diversity of animals.

Water skating in the larvae of dixella aestivalis (Diptera) and hydrobius fuscipes (Coleoptera)

1999 ◽  
Vol 202 (7) ◽  
pp. 845-853
Author(s):  
J. Brackenbury
Keyword(s):  
High Speed ◽  
The Body ◽  
Water Interface ◽  
Body Movements ◽  
Chironomid Larvae ◽  
High Speed Video ◽  
Adhesive Organ ◽  
Video Recordings ◽  
Air Water Interface

The kinematics of locomotion was investigated in the aquatic larvae of Dixella aestivalis and Hydrobius fuscipes with the aid of high-speed video recordings. Both insects are able to skate on the surface of the water using the dorso-apical tracheal gill as an adhesive organ or ‘foot’. Progress relies on the variable adhesion of the foot between ‘slide’ and ‘hold’ periods of the locomotory cycle. The flexural body movements underlying skating in D. aestivalis can be derived directly from the figure-of-eight swimming mechanism used in underwater swimming. The latter is shown to be similar to figure-of-eight swimming in chironomid larvae. This study shows how the deployment of a ‘foot’ enables simple side-to-side flexural movements of the body to be converted into effective locomotion at the air-water interface.

scholarly journals Swimming Turned on Its Head: Stability and Maneuverability of the Shrimpfish (Aeoliscus punctulatus)

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
F E Fish ◽  
R Holzman
Keyword(s):  
Cross Sections ◽  
Swimming Performance ◽  
Center Of Mass ◽  
Leading Edge ◽  
Longitudinal Axis ◽  
The Body ◽  
Maximum Speed ◽  
Vertical Orientation ◽  
Neutrally Buoyant ◽  
Orientation Modification

Synopsis The typical orientation of a neutrally buoyant fish is with the venter down and the head pointed anteriorly with a horizontally oriented body. However, various advanced teleosts will reorient the body vertically for feeding, concealment, or prehension. The shrimpfish (Aeoliscus punctulatus) maintains a vertical orientation with the head pointed downward. This posture is maintained by use of the beating fins as the position of the center of buoyancy nearly corresponds to the center of mass. The shrimpfish swims with dorsum of the body moving anteriorly. The cross-sections of the body have a fusiform design with a rounded leading edge at the dorsum and tapering trailing edge at the venter. The median fins (dorsal, caudal, anal) are positioned along the venter of the body and are beat or used as a passive rudder to effect movement of the body in concert with active movements of pectoral fins. Burst swimming and turning maneuvers by yawing were recorded at 500 frames/s. The maximum burst speed was 2.3 body lengths/s, but when measured with respect to the body orientation, the maximum speed was 14.1 body depths/s. The maximum turning rate by yawing about the longitudinal axis was 957.5 degrees/s. Such swimming performance is in line with fishes with a typical orientation. Modification of the design of the body and position of the fins allows the shrimpfish to effectively swim in the head-down orientation.

Simplified Triped Robot for Analysis of Three-Dimensional Gait Generation

2017 ◽  
Vol 29 (3) ◽  
pp. 528-535
Author(s):  
Yoichi Masuda ◽  
◽  
Masato Ishikawa
Keyword(s):  
High Speed ◽  
Force Feedback ◽  
Three Dimensional ◽  
Radial Symmetry ◽  
The Body ◽  
Walking Robots ◽  
Body Structure ◽  
Gait Patterns ◽  
Gait Generation ◽  
Proposed Model

[abstFig src='/00290003/08.jpg' width='230' text='The tripedal robot “Martian petit”' ] Significant efforts to simplify the body structure of multi-legged walking robots have been made over the years. Of these, the Spring-Loaded-Inverted-Pendulum (SLIP) model has been very popular, therefore widely employed in the design of walking robots. In this paper, we develop a SLIP-based tripedal walking robot with a focus on the geometric symmetry of the body structure. The proposed robot possesses a compact, light-weight, and compliant leg modules. These modules are controlled by a distributed control law that consists of decoupled oscillators with only local force feedback. As demonstrated through experiments, the simplified design of the robot makes possible the generation of high-speed dynamic locomotion. Despite the structural simplicity of the proposed model, the generation of several gait-patterns is demonstrated. The proposed minimalistic design approach with radial symmetry simplifies the function of each limb in the three-dimensional gait generation of the robot.

The kinematics and performance of escape responses of the knifefish Xenomystus nigri

1993 ◽  
Vol 71 (1) ◽  
pp. 189-195 ◽  
Author(s):  
M. A. Kasapi ◽  
P. Domenici ◽  
R. W. Blake ◽  
D. Harper
Keyword(s):  
High Speed ◽  
Longitudinal Axis ◽  
The Body ◽  
Maximum Acceleration ◽  
Low Speed ◽  
Average Maximum ◽  
Morphological Specialization ◽  
Escape Responses ◽  
And Performance ◽  
Stage 1

The kinematics and performance of the escape responses of the knifefish Xenomystus nigri, a fish specialized for low-speed, undulatory median-fin propulsion, were recorded by means of high-speed cinematography. Two types of escape were observed, one involving the formation of a C-shape along the longitudinal axis of the fish (stage 1), followed by a slow recoil of the body (single bend); the other (double bend) involved stage 1 followed by a contralateral bend (stage 2). The pectoral fins were extended throughout escapes of both types. The average maximum acceleration for double bend escapes was 127.98 m∙s−2; acceleration was usually greatest in stage 1. In double bend escapes, turning angles for stages 1 and 2 were not correlated. Pitch and roll orientations change during escapes. In stage 1, the average roll and average pitch were linearly correlated, suggesting that roll was partly responsible for establishing pitch. Knifefish achieved high maximum acceleration relative to other fish. Therefore, performance was not compromised by morphological specialization for low-speed swimming; however, a negative correlation of pitch with acceleration in stage 1 suggested that escapes involve a trade-off between acceleration and confusing a predator by changing planar orientation.

scholarly journals Experiment, Optimization, and Design of Electromagnetic Track Brake for High-Speed Railways System

2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Chun Xiang ◽  
Jun-Cheng Wang ◽  
Yu-Feng Gu ◽  
Shi-Jin Zhang ◽  
Shi-An Chen
Keyword(s):  
High Speed ◽  
Copper Wire ◽  
Final Height ◽  
Three Dimensional ◽  
Single Layer ◽  
Longitudinal Axis ◽  
Iron Core ◽  
Railway Systems ◽  
Magnetic Circuits ◽  
Final Design

To enhance braking force and control convenience of high-speed railway systems, this paper proposes a new electromagnetic track brake, and the corresponding design, optimization, and experimental test are implemented. The proposed track brake is longitudinal-axis magnetic circuits excited by multiple coils electromagnets, and the pole shoes are extending outward. A preliminary design of an electromagnetic track brake is developed, including iron core height, iron core width, iron core gap, excitation ampere-turn, coil arrangement form, coil thickness, and preliminary height of single-layer coil. The electromagnet number and pole shoe gap are optimized through three-dimensional electromagnetic simulation comparisons. The final design of the electromagnetic track brake is determined, including iron core length, copper wire diameter, coil turn, and final height of single-layer coil. Experimental verification of electromagnetic attractive force is performed through prototype tests, and the newly developed electromagnetic track brake can enhance electromagnetic braking deceleration by 39%.

Canal-Otolith Interactions After Off-Vertical Axis Rotations I. Spatial Reorientation of Horizontal Vestibuloocular Reflex

2000 ◽  
Vol 83 (3) ◽  
pp. 1522-1535 ◽  
Author(s):  
Karin Jaggi-Schwarz ◽  
Hubert Misslisch ◽  
Bernhard J. M. Hess
Keyword(s):  
Semicircular Canal ◽  
Three Dimensional ◽  
Head Tilt ◽  
Vertical Axis ◽  
Longitudinal Axis ◽  
The Body ◽  
Spatial Transformation ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Spatial Reorientation

We examined the three-dimensional (3-D) spatial orientation of postrotatory eye velocity after horizontal off-vertical axis rotations by varying the final body orientation with respect to gravity. Three rhesus monkeys were oriented in one of two positions before the onset of rotation: pitched 24° nose-up or 90° nose-up (supine) relative to the earth-horizontal plane and rotated at ±60°/s around the body-longitudinal axis. After 10 turns, the animals were stopped in 1 of 12 final positions separated by 30°. An empirical analysis of the postrotatory responses showed that the resultant response plane remained space-invariant, i.e., accurately represented the actual head tilt plane at rotation stop. The alignment of the response vector with the spatial vertical was less complete. A complementary analysis, based on a 3-D model that implemented the spatial transformation and dynamic interaction of otolith and lateral semicircular canal signals, confirmed the empirical description of the spatial response. In addition, it allowed an estimation of the low-pass filter time constants in central otolith and semicircular canal pathways as well as the weighting ratio between direct and inertially transformed canal signals in the output. Our results support the hypothesis that the central vestibular system represents head velocity in gravity-centered coordinates by sensory integration of otolith and semicircular canal signals.

Measuring the angle of attack of beating insect wings: robust three-dimensional reconstruction from two-dimensional images

1997 ◽  
Vol 200 (21) ◽  
pp. 2693-2704 ◽  
Author(s):  
A Willmott ◽  
C Ellington
Keyword(s):  
High Speed ◽  
Angle Of Attack ◽  
Three Dimensional ◽  
Numerical Algorithms ◽  
Longitudinal Axis ◽  
Wing Motion ◽  
Insect Wings ◽  
High Speed Film ◽  
Dimensional Reconstruction ◽  
Left And Right

A robust technique for determining the angle of attack of insect wings from film of free flight has to date proved elusive. This report describes the development of two new methods ­ the Strips and Planes techniques ­ which were designed to overcome some of the limitations experienced in previous studies. The accuracy and robustness of these novel methods were tested extensively using simulated hawkmoth wing outlines generated for a realistic range of wing positions and torsion. The results were compared with those from two existing methods ­ the Symmetry and Landmarks procedures. The performance of the latter technique will be strongly species-dependent; it could not be successfully applied to hawkmoth flight because of practical difficulties in obtaining suitable landmarks. The Planes method was the least successful of the remaining techniques, especially during those phases of the wingbeat when the orientations of the two wings relative to the camera viewpoint were similar. The Symmetry and Strips methods were tested further to investigate the effects on their performance of introducing additional camber or wing motion asymmetry. The results showed clearly that the Strips method should be the technique of choice wherever the axis of wing torsion is close to the longitudinal axis of the wing. The procedure involves the experimenter matching a model wing divided into chordwise strips to the true wing outline digitized from high-speed film. The use of strips rather than the points digitized in previous studies meant that the analysis required only one wing outline to be digitized. Symmetry of motion between the left and right wings is not assumed. The implications of requiring human input to the Strips method, as opposed to the strictly numerical algorithms of the alternative techniques, are discussed. It is argued that the added flexibility that this provides in dealing with images which have typically been recorded in suboptimal conditions outweighs the introduction of an element of subjectivity. Additional observations arising from the use of the Strips analysis with high-speed video sequences of hawkmoth flight are given.

From Verbal to Three-dimensional Digital Visual Texts: A Construction of a Javanese Prince

2020 ◽  
Author(s):  
Harry Nuriman ◽  
◽  
Nia Kurniasih ◽  
Setiawan Sabana ◽  
Intan R. Mutiaz ◽  
...  
Keyword(s):  
Motion Capture ◽  
Electronic Devices ◽  
Three Dimensional ◽  
The Body ◽  
Motion Capture Data ◽  
Visual Texts ◽  
Theatrical Performances ◽  
Physical Features ◽  
Capture Technique

Visualizations of the body of the famous Javanese Prince Diponegoro appears in various media, ranging across sketches, paintings, sculptures, banknotes and coins, shadow puppets, stamps, theatrical performances and electronic devices. All these visualizations mostly follow previous visualizations influenced by artist imaginations. This research seeks to present Prince Diponegoro in three-dimensional animated visualization using a motion capture technique. To complete this, the project draws from authentic manuscript research from the autobiography of Babad Diponegoro. Further, the project employs intertextuality as a method with which to interpolate the data, and hence to obtain a satisfactory overall visualization. The physical features, gestures and paralinguistic elements contained in the verbal text of Babad Diponegoro have been employed using motion capture data based on events written in the Babad Diponegoro. Many existing representations of the prince exist. However, this study attempts to rethink these existing visualizations, so as to produce a much more accurate, if not completely new, icon, thus differing to existing representations.

Body Roll and Handpath in Freestyle Swimming: An Experimental Study

1993 ◽  
Vol 9 (3) ◽  
pp. 238-253 ◽  
Author(s):  
Qi Liu ◽  
James G. Hay ◽  
James G. Andrews
Keyword(s):  
Mathematical Model ◽  
Experimental Study ◽  
Upper Limb ◽  
Three Dimensional ◽  
Time History ◽  
The Body ◽  
Long Distance ◽  
Lateral Component ◽  
3D Data ◽  
Body Roll

The purpose of this study was to determine the influence of (a) body roll, and (b) the motion of the arm relative to the trunk, on the medial-lateral component of the path followed by the hand during the pull phase in freestyle swimming. Ten male swimmers swam three trials of freestyle at a long-distance workout pace. Three-dimensional (3D) underwater videography was used to record the body roll angle-time history and the path followed by the hand during the pull phase. A mathematical model was used to characterize the motion of a swimmer's right upper limb in accord with 3D data from the videotape images, and to determine what the path of the hand would have been as a result of body roll alone. The contribution of body roll to the actual handpath was found to be nearly equal to the contribution of medial-lateral motions of the hand relative to the trunk.

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