Evolution toward asymmetrical gaits in Neotropical spiny rats (Rodentia: Echimyidae): evidences favoring adaptation

2007 ◽  
Vol 85 (6) ◽  
pp. 709-717 ◽  
Author(s):  
P.L.B. Rocha ◽  
S. Renous ◽  
A. Abourachid ◽  
E. Höfling
Keyword(s):  
Relative Velocity ◽  
High Speed ◽  
Gait Pattern ◽  
The Other ◽  
Time Lags ◽  
High Speed Camera ◽  
Adaptive Value ◽  
Trinomys Yonenagae ◽  
A Minor

The torch tail rat, Trinomys yonenagae Rocha, 1995 (family Echimyidae), is the morphologically most divergent of the spiny rats. In this study, we evaluate the hypothesis that gaits preferentially used by this species evolved as an adaptation to the desert-like dunes where they live. We filmed spontaneous locomotion of T. yonenagae, Trinomys albispinus minor Reis and Pessôa, 1995, and Proechimys cayennensis (Desmarest, 1817) with a high-speed camera. We detected, for each of the 323 cycles of the reference forelimb recorded, the kind of gait developed, the time lags between the touchdown of each pair of limbs, and the relative velocity. Trinomys yonenagae walked twice as fast as P. cayennensis and T. a. minor using mainly the asymmetrical transverse gallop, half-bounds, and bounds, while the other two species used mainly the lateral sequence walk. Gaits changed from symmetrical to asymmetrical with increasing velocity for T. yonenagae but not for the other species. We argue that the gait pattern found in T. yonenagae is autapomorphic, that its origin coincides with the shift to a desert-like habitat, and that this type of gait confers higher adaptive value to explore resources in open areas than the plesiomorphic pattern. Therefore, we conclude that it can be considered adaptive to life in the dunes.

scholarly journals Leader-chasing behavior in negative artificial triggered lightning flashes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Fukun Wang ◽  
Jianguo Wang ◽  
Li Cai ◽  
Rui Su ◽  
Wenhan Ding ◽  
...  
Keyword(s):  
High Speed ◽  
The Other ◽  
Lightning Flash ◽  
High Speed Camera ◽  
Return Stroke ◽  
Catching Up ◽  
Special Cases ◽  
Triggered Lightning

AbstractTwo special cases of dart leader propagation were observed by the high-speed camera in the leader/return stroke sequences of a classical triggered lightning flash and an altitude-triggered lightning flash, respectively. Different from most of the subsequent return strokes preceded by only one leader, the return stroke in each case was preceded by two leaders occurring successively and competing in the same channel, which herein is named leader-chasing behavior. In one case, the polarity of the latter leader was opposite to that of the former leader and these two combined together to form a new leader, which shared the same polarity with the former leader. In the other case, the latter leader shared the same polarity with the former leader and disappeared after catching up with the former leader. The propagation of the former leader in this case seems not to be significantly influenced by the existence of the latter leader.

scholarly journals The effect of a lack of uncapped brood on social interactions between honey bee workers and the queen

Apidologie ◽  
2021 ◽  
Author(s):  
Sylwia Łopuch ◽  
Adam Tofilski
Keyword(s):  
Social Interactions ◽  
Honey Bee ◽  
Honey Bees ◽  
High Speed ◽  
Egg Production ◽  
Social Contexts ◽  
The Other ◽  
High Speed Camera ◽  
Time Required ◽  
Honey Bee Workers

AbstractVibro-acoustic communication is used by honey bees in many different social contexts. Our previous research showed that workers interact with their queen outside of the swarming period by means of wing-beating behaviour. Therefore, the aim of this study was to verify the hypothesis that the wing-beating behaviour of workers attending the queen stimulates her to lay eggs. The behaviour of workers and the queen was recorded using a high-speed camera, at first in the presence of uncapped brood in the nest and then without one. None of the queens performed wing-beating behaviour. On the other hand, the workers attending the queen demonstrated this behaviour two times per minute, on average, even in the presence of uncapped brood in the nest. After removing the combs with the uncapped brood, the incidence of wing-beating behaviour increased significantly to an average of four times per minute. Wing-beating behaviour did not differ significantly in its characteristics when uncapped brood was present or absent in the nest. During 3 days after removing the combs with the uncapped brood, there was no significant increase in the rate of egg lying by the queen. Therefore, the results presented here do not convincingly confirm that the wing-beating behaviour of workers affects the rate of queen's egg-lying. This negative result can be related to colony disturbance and longer time required by the queen to increase egg production.

Mouth Shape Detection Based on Template Matching and Optical Flow for Machine Lip Reading

2013 ◽  
Vol 1 (1) ◽  
pp. 14-25 ◽  
Author(s):  
Tsuyoshi Miyazaki ◽  
Toyoshiro Nakashima ◽  
Naohiro Ishii
Keyword(s):  
Optical Flow ◽  
Template Matching ◽  
High Speed ◽  
Image Sequences ◽  
Previous Method ◽  
The Other ◽  
High Speed Camera ◽  
Improved Method ◽  
Time Period ◽  
Lip Reading

The authors describe an improved method for detecting distinctive mouth shapes in Japanese utterance image sequences. Their previous method uses template matching. Two types of mouth shapes are formed when a Japanese phone is pronounced: one at the beginning of the utterance (the beginning mouth shape, BeMS) and the other at the end (the ending mouth shape, EMS). The authors’ previous method could detect mouth shapes, but it misdetected some shapes because the time period in which the BeMS was formed was short. Therefore, they predicted that a high-speed camera would be able to capture the BeMS with higher accuracy. Experiments showed that the BeMS could be captured; however, the authors faced another problem. Deformed mouth shapes that appeared in the transition from one shape to another were detected as the BeMS. This study describes the use of optical flow to prevent the detection of such mouth shapes. The time period in which the mouth shape is deformed is detected using optical flow, and the mouth shape during this time is ignored. The authors propose an improved method of detecting the BeMS and EMS in Japanese utterance image sequences by using template matching and optical flow.

Laser Processing of Asteroid Simulants

2020 ◽  
Author(s):  
Niklas Anthony ◽  
Mikael Granvik ◽  
Christina Wanhainen ◽  
Jan Frostevarg ◽  
Heikki Suhonen ◽  
...  
Keyword(s):  
Energy Efficient ◽  
Laser Processing ◽  
High Speed ◽  
The Other ◽  
High Speed Camera ◽  
X Ray ◽  
Nd:Yag Lasers ◽  
Micro Tomography ◽  
Power Densities ◽  
Shed Light

<p>Asteroid mining and redirection are two trends that both can utilize lasers, one to drill and cut, the other to ablate and move. Yet little is known about what happens when a laser is used to process the types of materials we typically expect to find on most asteroids. To shed light on laser processing of asteroid material, we used pulsed Nd:YAG lasers on samples of olivine, pyroxene, and serpentine, and studied the process with a high-speed camera and illumination laser at 10~000~frames~per~second. We also measure the sizes of the resulting holes using X-ray micro-tomography to find the pulse parameters which remove the largest amount of material using the least amount of energy. We find that at these power densities, all three minerals will melt and chaotically throw off spatter. Short, low-power pulses can efficiently produce thin, deep holes, and long, high-power pulses are more energy efficient at removing the most amount of material. We wil also present some preliminary results of the effects of spallation of these materials.</p>

Effect of initial pressure of oblique-blowing airflow and folding-in airflow on yarn tucked-in in the pneumatic tucked-in selvedge apparatus

2021 ◽  
pp. 004051752110134
Author(s):  
Yisheng Liu ◽  
Xinlei Zhou ◽  
Xiaoying Cheng ◽  
Dandan Liu
Keyword(s):  
Numerical Model ◽  
High Speed ◽  
Laboratory Experiments ◽  
Initial Pressure ◽  
The Other ◽  
High Speed Camera ◽  
Simulation Data ◽  
Structure Interaction ◽  
Airflow Field ◽  
The One

In this paper, numerical simulation and laboratory experiments were combined to research the tucked-in behavior of the yarn in the pneumatic tucked-in selvedge apparatus, and explore the effect of initial pressure of oblique-blowing airflow and folding-in airflow on yarn tucked-in. This work focused on the motion of a single yarn of which one end was fixed while the other was free. Initial pressures for oblique-blowing airflow and folding-in airflow were set as parameters. A numerical model was developed to simulate the process based on the one-way fluid–structure interaction. Then a laboratory experiment was carried out with the help of a high-speed camera to record the motion behaviors of yarns. The motions were compared with the simulation data and showed that the proposed numerical model can properly replicate the motion of yarn and its points in the airflow field. Each group of yarns with different initial pressures was able to be tucked-in and had an elongation. Increasing the initial pressures of oblique-blowing airflow from 0.3 MPa to 0.4 MPa and folding-in airflow from 0.35 MPa to 0.4MPa shortened the time for the yarn to complete the entire oblique-blowing and tucked-in process by 0.4625 ms, and extended the yarn elongation by 0.151 mm.

scholarly journals Using High-Speed Photography to Study Undercatch in Tipping-Bucket Rain Gauges*

2014 ◽  
Vol 31 (6) ◽  
pp. 1330-1336 ◽  
Author(s):  
Claude Duchon ◽  
Christopher Fiebrich ◽  
David Grimsley
Keyword(s):  
High Speed ◽  
Rain Rate ◽  
Slow Motion ◽  
Rain Gauge ◽  
The Other ◽  
High Speed Photography ◽  
High Speed Camera ◽  
Rain Gauges ◽  
Linear Correction ◽  
Rain Rates

Abstract To better understand the undercatch process associated with tipping-bucket rain gauges, a high-speed camera normally used in determining the structure of lightning was employed. The photo rate was set at 500 frames per second to observe the tipping of the bucket in a commonly used tipping-bucket rain gauge. The photos showed detail never seen before as the bucket tipped from one side to the other. Two fixed rain rates of 19.9 mm h−1 (0.78 in. h−1) and 175.2 mm h−1 (6.90 in. h−1), the minimum and maximum available, respectively, were used. The data from four tips at each rain rate were examined. The results show that the time from the beginning of a tip to the time the bucket assembly is horizontal—defined as the period during which undercatch occurs—was an average of 0.450 s for the eight cases. The average time for a complete tip was 0.524 s; thus, the vast majority of the time of a tip, 86%, is spent in undercatch mode. Because there was no apparent dependence of these times on rain rate, it should be possible to apply an accurate linear correction for undercatch as a function of rain rate given the time that undercatch occurs during a tip. Over all eight tips, the undercatch was found to be 0.98% for the 19.9 mm h−1 rate and 8.78% for the 175.2 mm h−1 rate. The procedure used to estimate the undercatch is described. Slow motion videos of the tipping of a bucket are available online.

scholarly journals High-speed camera test of newly developed igniter’s charges for artillery rounds

2021 ◽  
Vol 2090 (1) ◽  
pp. 012129
Author(s):  
A Plachá ◽  
J Recko
Keyword(s):  
High Speed ◽  
The Other ◽  
Ignition Process ◽  
High Speed Camera ◽  
Test Results ◽  
Black Powder ◽  
Time To Ignition ◽  
Military Institute ◽  
The Military

Abstract The article presents the results of the high-speed camera test of newly developed igniter’s charges for artillery rounds. The test was performed to take a closer look at the ignition process of mixtures, that is, to check the time-to-ignition of samples, and to assess the presence and quantity of solid igniting particles (if any). Five compositions were tested: Three of them contained the new igniter’s charges developed by the Military Institute of Armament Technology, and the other two contained black powder in different granularity classes as a comparison mixture. This article presents the collated test results.

scholarly journals Experimental Motion Analysis of Radially Rotating Beams Using High-Speed Camera and Motion Analyzer

1996 ◽  
Vol 3 (4) ◽  
pp. 293-301
Author(s):  
K.H. Low ◽  
Michael W.S. Lau ◽  
K.K. Low
Keyword(s):  
Strain Measurement ◽  
Vibration Analysis ◽  
High Speed ◽  
Reference Points ◽  
The Other ◽  
Strain Gauges ◽  
High Speed Camera ◽  
Flexible Beams ◽  
Vibrating Beams ◽  
Vibration Parameters

Although strain gauges can be attached to a system for vibration analysis, wires connected to the strain gauges may disturb the system and affect the accuracy of the strain measurement. As an alternative, this work presents the use of a high-speed camera combined with a motion analyzer to study the motion of rotating flexible beams. One end of the beam is rigidly connected to a motor, while the other end is free. White stickers placed on selected points on a given beam are the reference points in a digitization process. The modes of the vibrating beams can be filmed and analyzed. The vibration parameters, such as deflection and frequency, can be obtained by using a film motion analyzer. The results show that the beam does not behave in a clamped-free or a pinned-free fashion, but instead occurs at an intermediate boundary between these two classical conditions.

Observation of Melting Wire Solder for Sleeve Soldering

2015 ◽  
Author(s):  
Hajime Nomura ◽  
Ken Imanishi ◽  
Shinichi Enoki ◽  
Mitsuo Ebisawa ◽  
Katsuyuki Tsuji
Keyword(s):  
Oxide Film ◽  
Metal Surface ◽  
High Speed ◽  
The Other ◽  
High Speed Camera ◽  
Two Factors ◽  
Solder Balls ◽  
Through Hole ◽  
Proper Condition ◽  
Observation Results

Wire solders usually contain flux and it can remove an oxide film on the metal surface chemically. The influence of the flux is important in soldering. Recently, the new packaging technology was developed, it is called Sleeve soldering. It is a kind of through-hole technology. Sleeve soldering can prevent to spatter flux contained in the wire solder and solder balls. It is not known behaviors of melting wire solder in the sleeve. The purpose of this study is to investigate the behaviors and to obtain proper conditions for Sleeve soldering. The proper condition consists of two factors. One is temperature of the sleeve. The other is amounts of wire solder. The behavior of melting wire solder in the sleeve is observed using a high speed camera. This paper describes observation results using a high-speed camera and influences of the flux in Sleeve soldering.

A NEW SLOW-MOTION REPLAY EXTRACTOR FOR SOCCER GAME VIDEOS

2003 ◽  
Vol 17 (08) ◽  
pp. 1467-1481 ◽  
Author(s):  
EN-JUNG FARN ◽  
LING-HWEI CHEN ◽  
JENN-HANN LIOU
Keyword(s):  
High Speed ◽  
Slow Motion ◽  
Experimental Results ◽  
The Other ◽  
Single Shot ◽  
High Speed Camera ◽  
Soccer Game

In this paper, we will present a method to extract slow-motion replays in a soccer game video. According to our observation, a slow-motion replay always happens as a single shot and appears between two gradual transitions. Based on this fact, a video will first be segmented into individual shots and only those shots appearing between two gradual transitions are considered as candidate shots. There are two kinds of slow-motion replays. One comes from a standard camera and consists of some repeating or inserted frames. The other is from a high-speed camera with larger variation between two consecutive frames. Based on these features, an extractor is then provided to check if a candidate shot is a slow motion replay. Some experimental results are given to show the effectiveness of the proposed method.

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