Anguilliform locomotion in an elongate salamander (Siren intermedia): effects of speed on axial undulatory movements

1997 ◽  
Vol 200 (4) ◽  
pp. 767-784 ◽  
Author(s):  
G Gillis
Keyword(s):  
Swimming Speed ◽  
High Speed ◽  
Lateral Displacement ◽  
Small Sample Size ◽  
Body Position ◽  
Orientation Angle ◽  
Small Sample ◽  
The Body ◽  
Lateral Velocity ◽  
Forward Movement

Many workers interested in the mechanics and kinematics of undulatory aquatic locomotion have examined swimming in fishes that use a carangiform or subcarangiform mode. Few empirical data exist describing and quantifying the movements of elongate animals using an anguilliform mode of swimming. Using high-speed video, I examine the axial undulatory kinematics of an elongate salamander, Siren intermedia, in order to provide data on how patterns of movement during swimming vary with body position and swimming speed. In addition, swimming kinematics are compared with those of other elongate vertebrates to assess the similarity of undulatory movements within the anguilliform locomotor mode. In Siren, most kinematic patterns vary with longitudinal position. Tailbeat period and frequency, stride length, Froude efficiency and the lateral velocity and angle of attack of tail segments all vary significantly with swimming speed. Although swimming speed does not show a statistically significant effect on kinematic variables such as maximum undulatory amplitude (which increases non-linearly along the body), intervertebral flexion and path angle, examination of the data suggests that speed probably has subtle and site-specific effects on these variables which are not detected here owing to the small sample size. Maximum lateral displacement and flexion do not coincide in time within a given tailbeat cycle. Furthermore, the maximum orientation (angle with respect to the animal's direction of forward movement) and lateral velocity of tail segments also do not coincide in time. Comparison of undulatory movements among diverse anguilliform swimmers suggests substantial variation across taxa in parameters such as tailbeat amplitude and in the relationship between tailbeat frequency and swimming speed. This variation is probably due, in part, to external morphological differences in the shape of the trunk and tail among these taxa.

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.

scholarly journals A COMPARATIVE CLINICAL STUDY ON JARA WITH RESPECT TO AGEING PROCESS WITH ASHWAGANDHA RASAYANA AND MATRA BASTI

2016 ◽  
Author(s):  
Singh Binod Kumar ◽  
Bharkher D.L
Keyword(s):  
Life Expectancy ◽  
Small Sample Size ◽  
Small Sample ◽  
The Body ◽  
World Health ◽  
Ageing Process ◽  
Health Security ◽  
Chief Complaints ◽  
Comparative Clinical Study ◽  
Later Phase

The problem of ageing is experienced by all the countries. According to World Health statistics the life expectancy of Nepalese people has risen from 58.91 years to 67.86 years (1996 to 2015). Ageing is emerging issue in Nepal as well as global. Its tempo is expected to be unexpectedly fast as mortality continues to decline and life expectancy continues to increase. Ayurveda the science of life has observed ageing as a Jara avastha, which is a later phase of life, it is natural, inevitable phenomenon, in which maximum decline of bodily elements that may become as major cause of disability and functional dependency requiring services that affect many sectors of economy, health, security, income, housing, transportation etc. Jara chikitsa has been mentioned as one independent Anga in Ashtanga Ayurveda where Rasayana therapy is capable to impede the ageing process and to delay the degenerative process in the body. In this study we measured the effectiveness of Ashwagandha rasayana and Matra basti and compared with the Ashwagandha Rasayan only in Jara avastha. A total of thirty elderly patients were selected and divided in two groups A and B, given them either Ashwagandha Rasayana with Matra basti or Ashwagandha rasayana in prescribed doses for 45 days. Changes in the subjective complaints, objective parameters of the patients and appearance of adverse events were also evaluated. Both the groups provided better results on the chief complaints But, comparison in between both the groups is insignificant, that may be due to small sample size.

Role of Trace andamp; Toxic Elements in the Development of Anaemia in School going population of Hyderabad

2019 ◽  
Vol 41 (3) ◽  
pp. 405-405
Author(s):  
Junaid Ali Thebo Junaid Ali Thebo ◽  
Shaista Khan Shaista Khan ◽  
Abdul Aziz Shaikh Abdul Aziz Shaikh ◽  
Nasren Thebo Nasren Thebo ◽  
Ghulam Nabi Ghulam Nabi ◽  
...  
Keyword(s):  
Trace Elements ◽  
Small Sample Size ◽  
Venous Blood ◽  
Research Work ◽  
Small Sample ◽  
The Body ◽  
Control Group ◽  
Severe Anemia ◽  
Informed Consent Form ◽  
Lead Levels

The aim of this research work was to measure the concentration of essential trace elements, including serum copper, iron and zinc in children suffering from anemia, and also to investigate the effect of heavy metal like lead on causing anemia. The study has been performed on school going children living in Hyderabad, which is a mini industrialized city. The study was carried out in anemic children studying in different schools of Hyderabad having different age groups. 10 ml venous blood samples were obtained after an informed consent form was signed.The samples were used to analyzed the trace elements (Fe,Cu, Zn) and toxic metal Lead (Pb). Trace elements include zinc and copper were found elevated in anemic children than healthy one, Copper is involved in many vital mechanisms in the body, energy production, connective tissue formation, and Fe metabolism, whereas copper found low with relation to the iron in anemic children because copper helps in the absorption of iron. Zinc is an essential micronutrient demanded by living being because of its significant position in-cooperation with structural constituent of proteins and as a cofactor in enzyme catalysis, there is difference between zinc and iron, they have been found to inhibit each other’s absorption due to their competitive absorption pathways. Increased zinc levels found in children with low iron content, whereas control group have normal results of these elements which may be due to their dietary management. The results revealed the environmental pollution and the associated health risks on exposure to lead. Pb concentrations whereas the current research stated a considerable relationship of mild and severe anemia with 10-42.2μg/dl Pb concentrations, the variation in results may be due to a small sample size in the current study, Drinking water from corrosion of plumbing systems through the use of lead sellers and other lead containing materials in connecting household plumbing to public water supplies. Ground and surface water are also contaminated by lead consuming industry and agricultural activities. The concentrations of Pb greater than or equal to (≥)10 μg/dl in children related with an increased threat of mild and severe anemia, diminishing iron absorption . High Lead levels were related with lower concentrations of iron, ferritin and copper, in this study it was found that high levels of lead were found mostly in boys. Lead levels have also found in control group which was below 5 ug/dl, according to WHO ≥ 10 ug/dl is considered as high.

Kinematics and efficiency of steady swimming in adult axolotls (Ambystoma mexicanum)

1997 ◽  
Vol 200 (13) ◽  
pp. 1863-1871 ◽  
Author(s):  
K D'Août ◽  
P Aerts
Keyword(s):  
Swimming Speed ◽  
High Speed ◽  
Natural Habitat ◽  
Total Body Length ◽  
Ambystoma Mexicanum ◽  
The Body ◽  
Entire Body ◽  
Amplitude Profile ◽  
Wide Range ◽  
Tail Tip

The kinematics of steady swimming at a wide range of velocities was analysed using high-speed video recordings (500 frames s-1) of eight individuals of Ambystoma mexicanum swimming through a tunnel containing stationary water. Animals in the observed size range (0.135­0.238 m total body length) prefer to swim at similar absolute speeds, irrespective of their body size. The swimming mechanism is of the anguilliform type. The measured kinematic variables ­ the speed, length, frequency and amplitude (along the entire body) of the propulsive wave ­ are more similar to those of anguilliform swimming fish than to those of tadpoles, in spite of common morphological features with the latter, such as limbs, external gills and a tapering tail. The swimming speed for a given animal size correlates linearly with the tailbeat frequency (r2=0.71), whereas the wavelength and tail-tip amplitude do not correlate with this variable. The shape of the amplitude profile along the body, however, is very variable between the different swimming bouts, even at similar speeds. It is suggested that, for a given frequency, the amplitude profile along the body is adjusted in a variable way to yield the resulting swimming speed rather than maintaining a fixed-amplitude profile. The swimming efficiency was estimated by calculating two kinematic variables (the stride length and the propeller efficiency) and by applying two hydrodynamic theories, the elongated-body theory and an extension of this theory accounting for the slope at the tail tip. The latter theory was found to be the most appropriate for the axolotl's swimming mode and yields a hydromechanical efficiency of 0.75±0.04 (mean ± s.d.), indicating that Ambystoma mexicanum swims less efficiently than do anuran tadpoles and most fishes. This can be understood given its natural habitat in vegetation at the bottom of lakes, which would favour manoeuvrability and fast escape.

scholarly journals ARTIFICIAL NEURAL NETWORKS BASED SLEEP MOTION RECOGNITION USING NIGHT VISION CAMERAS

2004 ◽  
Vol 16 (02) ◽  
pp. 79-86 ◽  
Author(s):  
CHUNG-HSIEN KUO ◽  
FANG-CHUNG YANG ◽  
MING-YUAN TSAI ◽  
MING-YIH LEE
Keyword(s):  
Neural Networks ◽  
High Speed ◽  
Body Position ◽  
Body Movement ◽  
The Body ◽  
Night Vision ◽  
Ann Model ◽  
Motion Recognition ◽  
Video Frames ◽  
Artificial Neural

The body movement is one of the most important factors to evaluate the sleep quality. In general, the sleep motion is hardly investigated, and it must take a long time to observe the motion of the patient in terms of a pre-recoded video storage media with high speed playing. This paper proposes an image-based solution to recognize the sleep motions. We use the contact free and IR-based night vision camera to capture the video frames during the sleep of the patient. The video frames are used to recognize the body positions and the body directions such as the “body up”, “body down”, “body right”, and “body left”. In addition to the image processing, the proposed artificial neural network (ANN) sleep motion recognition solution is composed of two neural networks. These two neural networks are organized as in a cascade configuration. The first ANN model is used to identify the body position features from the images; and the follower ANN model is constructed based on the features that are identified by the first ANN model to recognize the body direction. Finally, the implementations and the practical results of this work are all illustrated in this paper.

Quantitative analysis of prey-capture kinematics in Anolis equestris (Reptilia: Iguanidae)

1990 ◽  
Vol 68 (10) ◽  
pp. 2192-2198 ◽  
Author(s):  
Vincent L. Bels
Keyword(s):  
High Speed ◽  
Prey Capture ◽  
Anterior Part ◽  
The Body ◽  
Original Position ◽  
Forward Movement ◽  
Live Prey ◽  
Capture Process ◽  
Locomotor System ◽  
Cyclic Movement

High-speed cinematography was employed to study the mechanics of prey capture in Anolis equestris. Capture of live prey (adult locusts) consists of a cyclic movement of the upper and lower jaws combined with tongue protraction. Kinematic profiles are presented for the jaws, tongue, and forelimbs. The tongue is projected during the "slow open" stage and most of the "fast open" stage. The tongue protrudes beyond the mandibular symphysis during the slow open stage, and rotates simultaneously around a transverse anteromedian axis. The prey is thus contacted by the dorsal sticky surface of the tongue, and then pulled backward into the oral cavity by a combination of a forward movement of the jaws and retraction of the tongue. Gape angle, defined as the angle between the upper and lower jaws, continues to increase during the initial stages of tongue retraction. During the capture process, the anterior part of the body lunges forward, followed by a return to its original position; this displacement is mediated by the forelimbs, which usually remain well anchored to the floor. The cyclic food-capture movements of the jaws and tongue–hyoid system in A. equestris (Iguanidae) and Chameleo dilepis (Chamaeleontidae) are compared. I argue that one of the primary selection forces in the evolution of the different mechanisms of prey prehension in these two lizard groups was enhancement of the locomotor system and, consequently, foraging ability.

scholarly journals Hydrodynamics of linear acceleration in bluegill sunfish Lepomis macrochirus

2018 ◽  
Author(s):  
Tyler N. Wise ◽  
Margot A. B. Schwalbe ◽  
Eric D. Tytell
Keyword(s):  
Swimming Speed ◽  
High Speed ◽  
Fluid Dynamic ◽  
Natural Habitat ◽  
Lepomis Macrochirus ◽  
Linear Acceleration ◽  
High Amplitude ◽  
The Body ◽  
Bluegill Sunfish ◽  
Tail Beat

SUMMARY STATEMENTBluegill sunfish accelerate primarily by increasing the total amount of force produced in each tail beat but not by substantially redirecting forces.ABSTRACTIn their natural habitat, fish rarely swim steadily. Instead they frequently accelerate and decelerate. Relatively little is known about how fish produce extra force for acceleration in routine swimming behavior. In this study, we examined the flow around bluegill sunfish Lepomis macrochirus during steady swimming and during forward acceleration, starting at a range of initial swimming speeds. We found that bluegill produce vortices with higher circulation during acceleration, indicating a higher force per tail beat, but do not substantially redirect the force. We quantified the flow patterns using high speed video and particle image velocimetry and measured acceleration with small inertial measurement units attached to each fish. Even in steady tail beats, the fish accelerates slightly during each tail beat, and the magnitude of the acceleration varies. In steady tail beats, however, a high acceleration is followed by a lower acceleration or a deceleration, so that the swimming speed is maintained; in unsteady tail beats, the fish maintains the acceleration over several tailbeats, so that the swimming speed increases. We can thus compare the wake and kinematics during single steady and unsteady tailbeats that have the same peak acceleration. During unsteady tailbeats when the fish accelerates forward for several tailbeats, the wake vortex forces are much higher than those at the same acceleration during single tailbeats in steady swimming. The fish also undulates its body at higher amplitude and frequency during unsteady tailbeats. These kinematic changes likely increase the fluid dynamic added mass of the body, increasing the forces required to sustain acceleration over several tailbeats. The high amplitude and high frequency movements are also likely required to generate the higher forces needed for acceleration. Thus, it appears that bluegill sunfish face a tradeoff during acceleration: the body movements required for acceleration also make it harder to accelerate.

Firms’ Specific Determinants of Capital Structure: An Analysis into Construction Firms in Malaysia and Singapore

2021 ◽  
Vol 7 ◽  
pp. 76-91
Author(s):  
Siti Zulaikha Binti Upilin ◽  
Hapsah S.Mohammad
Keyword(s):  
Capital Structure ◽  
Firm Size ◽  
Small Sample Size ◽  
Panel Data Analysis ◽  
Agency Cost ◽  
Small Sample ◽  
The Body ◽  
Construction Firms ◽  
The Impact ◽  
The Capital Structure

The study aims to examine the firm-specific factors such as firm size, profitability and asset tangibility in the capital structure decisions (leverage) on a sample of twenty construction firms in Malaysia and Singapore from 2009 to 2018, with 200 observations. The sample firms are chosen based on convenience sampling technique and the availability of the data. Prior studies documented inconclusive findings on the determinants of capital structure and different industries tend to reveal different patterns of relationship. In addition, the empirical evidence on comparative analysis between construction firms in Malaysia and Singapore is lacking. Hence, the objective of this study is to extend the prior work by investigating the impact of the determinants on capital structure on the construction firms in Malaysia and Singapore. The study uses panel data analysis to test the effectivity of trade-off, pecking order and agency cost theories of capital structure. The empirical findings reveal positive and significant association between firm size and capital structure for Singapore firms. Meanwhile, profitability and asset tangibility correlate negatively with capital structure. As for Malaysian firms, the three determinants exhibit insignificant association with the capital structure. The study only examines 10 construction firms in Malaysia and 10 construction firms in Singapore, therefore, the small sample size becomes the limitation of the study. Nevertheless, the findings of this study may contribute to the body of knowledge on the importance of some firm-specific determinants such as profitability, tangible assets, and firm size in order to determine the optimal level of capital structure for firms in these countries.

Estimating Exceedance Probabilities of Railway Bridge Vibrations in the Presence of Random Rail Irregularities

2020 ◽  
Vol 20 (13) ◽  
pp. 2041005
Author(s):  
Patrick Salcher ◽  
Christoph Adam
Keyword(s):  
Stochastic Process ◽  
High Speed ◽  
Small Sample Size ◽  
Random Variable ◽  
Simulation Method ◽  
Small Sample ◽  
Computationally Efficient ◽  
Subset Simulation ◽  
Rail Irregularities ◽  
Response Thresholds

This contribution addresses the estimation of exceedance probabilities of the dynamic random response of railway bridges subjected to high-speed trains in the presence of random rail irregularities. The random nature of the irregular rail track is described by a spatial ergodic stochastic process, and consequently the dynamic bridge response becomes a stochastic process in time with generally unknown distributions. Using numerical simulation methods, the response thresholds for bridge deflection and acceleration are estimated to obtain small exceedance probabilities. Combining these limits with the response at perfect rail geometry provides an estimate of the dynamic response amplification due to random rail irregularities. This is in line with the semi-probabilistic safety concept of modern civil engineering, where critical response thresholds for structures are associated with small exceedance probabilities. It is shown that modeling the maximum bridge deflection as a normally distributed random variable with parameters fitted to the results of a Monte Carlo simulation with small sample size is a computationally efficient approach for estimating the amplified deflection. In contrast, the random maximum bridge acceleration is better captured by a lognormal distribution. As an efficient alternative, the subset simulation method provides accurate predictions for very small exceedance probabilities. If the amplitudes of the rail irregularities at discrete spatial coordinates along the rail axis are considered as random variables, the stability of subset simulation increases.

scholarly journals Characterization of proprioceptive system dynamics in behaving Drosophila larvae using high-speed volumetric microscopy

2018 ◽  
Author(s):  
Rebecca Vaadia ◽  
Wenze Li ◽  
Venkatakaushik Voleti ◽  
Aditi Singhania ◽  
Elizabeth M.C. Hillman ◽  
...  
Keyword(s):  
High Speed ◽  
Body Position ◽  
Activity Patterns ◽  
The Body ◽  
Larval Body ◽  
Activity Measurements ◽  
Natural Movement ◽  
Rigid Joints

SummaryProprioceptors provide feedback about body position that is essential for coordinated movement. Proprioceptive sensing of the position of rigid joints has been described in detail in several systems, however it is not known how animals with an elastic skeleton encode their body positions. Understanding how diverse larval body positions are dynamically encoded requires knowledge of proprioceptor activity patterns in vivo during natural movement. Here we applied high-speed volumetric SCAPE microscopy to simultaneously track the position, physical deformation, and temporal patterns of intracellular calcium activity of multidendritic proprioceptors in crawling Drosophila larvae. During the periodic segment contraction and relaxation that occurs during crawling, proprioceptors with diverse morphologies showed sequential onset of activity throughout each periodic episode. A majority of these proprioceptors showed activity during segment contraction with one neuron type activated by segment extension. Different timing of activity of contraction-sensing proprioceptors was related to distinct dendrite terminal targeting, providing a continuum of position encoding during all phases of crawling. These dynamics could endow different proprioceptors with specific roles in monitoring the progression of contraction waves, as well as body shape during other behaviors. We provide activity measurements during exploration as one example. Our results provide powerful new insights into the body-wide neuronal dynamics of the proprioceptive system in crawling Drosophila, and demonstrate the utility of our approach for characterization of neural encoding throughout the nervous system of a freely behaving animal.

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