scholarly journals How to stick the landing: kangaroo rats use their tails to reorient during evasive jumps away from predators

2021 ◽  
Author(s):  
M Janneke Schwaner ◽  
Grace A Freymiller ◽  
Rulon W Clark ◽  
Craig P McGowan
Keyword(s):  
Angular Momentum ◽  
Rotation Axis ◽  
Average Rate ◽  
Tail Length ◽  
Rate Of Change ◽  
Video Data ◽  
The Body ◽  
Full Potential ◽  
Kangaroo Rats ◽  
Predator Attack

Abstract Tails are widespread in the animal world and play important roles in locomotor tasks, such as propulsion, maneuvering, stability, and manipulation of objects. Kangaroo rats, bipedal hopping rodents, use their tail for balancing during hopping, but the role of their tail during the vertical evasive escape jumps they perform when attacked by predators has yet to be determined. Because we observed kangaroo rats swinging their tails around their bodies while airborne following escape jumps, we hypothesized that kangaroo rats use their tails to not only stabilize their bodies while airborne, but also to perform aerial re-orientations. We collected video data from free-ranging desert kangaroo rats (D. deserti) performing escape jumps in response to a simulated predator attack and analyzed the rotation of their bodies and tails in the yaw plane (about the vertical-axis). Kangaroo rat escape responses were highly variable. The magnitude of body re-orientation in yaw was independent of jump height, jump distance, and aerial time. Kangaroo rats exhibited a stepwise re-orientation while airborne, in which slower turning periods corresponded with the tail center of mass being aligned close to the vertical rotation axis of the body. To examine the effect of tail motion on body reorientation during a jump, we compared average rate of change in angular momentum. Rate of change in tail angular momentum was nearly proportional to that of the body, indicating that the tail reorients the body in the yaw plane during aerial escape leaps by kangaroo rats. Although kangaroo rats make dynamic 3D movements during their escape leaps, our data suggests that kangaroo rats use their tails to control orientation in the yaw plane. Additionally, we show that kangaroo rats rarely use their tail length at full potential in yaw, suggesting the importance of tail movement through multiple planes simultaneously.

scholarly journals Balance training improves feedback control of perturbed balance in older adults

2021 ◽  
Author(s):  
Leila Alizadehsaravi ◽  
Sjoerd M. Bruijn ◽  
Jaap H. van Dieen
Keyword(s):  
Older Adults ◽  
Angular Momentum ◽  
Feedback Control ◽  
Center Of Mass ◽  
Balance Training ◽  
Rate Of Change ◽  
The Body ◽  
Balance Performance ◽  
Short Term

Recovering balance after perturbations becomes challenging with aging, but an effective balance training could reduce such challenges. In this study, we examined the effect of balance training on feedback control after unpredictable perturbations by investigating balance performance, recovery strategy, and muscle synergies. We assessed the effect of balance training on unipedal perturbed balance in twenty older adults (>65 years) after short-term (one session) and long-term (3-weeks) training. Participants were exposed to random medial and lateral perturbations consisting of 8-degree rotations of a robot-controlled balance platform. We measured full-body 3D kinematics and activation of 9 muscles (8 stance leg muscles, one trunk muscle) during 2.5 s after the onset of perturbation. The perturbation was divided into 3 phases: phase1 from the onset to maximum rotation of the platform, phase 2 from the maximum rotation angle to the 0-degree angle and phase 3 after platform movement. Balance performance improved after long-term training as evidenced by decreased amplitudes of center of mass acceleration and rate of change of body angular momentum. The rate of change of angular momentum did not directly contribute to return of the center of mass within the base of support, but it reoriented the body to an aligned and vertical position. The improved performance coincided with altered activation of synergies depending on the direction and phase of the perturbation. We concluded that balance training improves control of perturbed balance, and reorganizes feedback responses, by changing temporal patterns of muscle activation. These effects were more pronounced after long-term than short-term training.

THE BEHAVIOR OF ROTATING BODIES THAT EMIT GRAVITATIONAL WAVES IN GENERAL RELATIVITY

2000 ◽  
Vol 15 (17) ◽  
pp. 1107-1115
Author(s):  
F. I. COOPERSTOCK
Keyword(s):  
Angular Momentum ◽  
Gravitational Waves ◽  
Source Region ◽  
Rate Of Change ◽  
The Body ◽  
Material System ◽  
Classical Systems ◽  
Additional Information ◽  
The Moment ◽  
Rotating Bodies

Recently we demonstrated that Eddington's spinning rod lost "kinetic" energy but preserved its total energy while emitting gravitational waves. Additional information is now determined by analyzing the angular momentum of the rod. We develop an expression for the angular momentum loss of the material system alone with an integration over the source region. As expected, it is found that the moment of inertia of the rod increases as the rotation rate diminishes in analogy with typical classical systems. Its rate of change is determined in relation to the angular deceleration of the body.

The vorticity equation as an angular momentum equation

1973 ◽  
Vol 74 (2) ◽  
pp. 365-367 ◽  
Author(s):  
P. C. Chatwin
Keyword(s):  
Angular Momentum ◽  
Stokes Equations ◽  
Momentum Equation ◽  
Rate Of Change ◽  
The Body ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Material Volume ◽  
The Moment ◽  
Image Position

In a Newtonian fluid, in which the body forces are conservative, in which the pressure is a function only of density and in which the kinematic viscosity v is uniform, the vorticity ω satisfies the equationwhere u is the velocity field, so that ω = ▿ × u. This equation is normally derived by taking the curl of the Navier–Stokes equations. However, the vorticity has many interpretations in terms of the angular velocity of elements of fluid and it is natural to expect that (1) can be derived by equating the rate of change of the angular momentum of a small material volume element about its centre of mass with the moment of the forces acting on the element. Such a derivation is presented here in the hope that it may be of pedagogic interest.

scholarly journals Weight Feedback-Based Harmonic MDG-Ensemble Model for Prediction of Traffic Accident Severity

2021 ◽  
Vol 11 (11) ◽  
pp. 5072
Author(s):  
Byung-Kook Koo ◽  
Ji-Won Baek ◽  
Kyung-Yong Chung
Keyword(s):  
Traffic Accidents ◽  
Average Rate ◽  
Modern Society ◽  
Rate Of Change ◽  
Weighted Voting ◽  
Independent Variables ◽  
Dependent Variables ◽  
Accident Severity ◽  
Harmonic Average ◽  
Bagging Method

Traffic accidents are emerging as a serious social problem in modern society but if the severity of an accident is quickly grasped, countermeasures can be organized efficiently. To solve this problem, the method proposed in this paper derives the MDG (Mean Decrease Gini) coefficient between variables to assess the severity of traffic accidents. Single models are designed to use coefficient, independent variables to determine and predict accident severity. The generated single models are fused using a weighted-voting-based bagging method ensemble to consider various characteristics and avoid overfitting. The variables used for predicting accidents are classified as dependent or independent and the variables that affect the severity of traffic accidents are predicted using the characteristics of causal relationships. Independent variables are classified as categorical and numerical variables. For this reason, a problem arises when the variation among dependent variables is imbalanced. Therefore, a harmonic average is applied to the weights to maintain the variables’ balance and determine the average rate of change. Through this, it is possible to establish objective criteria for determining the severity of traffic accidents, thereby improving reliability.

scholarly journals An Intelligent Baby Monitor with Automatic Sleeping Posture Detection and Notification

AI ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 290-306
Author(s):  
Tareq Khan
Keyword(s):  
Language Translation ◽  
Video Data ◽  
The Body ◽  
Night Vision ◽  
Monitoring Device ◽  
Peace Of Mind ◽  
Image Processing Techniques ◽  
Pose Detection ◽  
Processing Techniques ◽  
Monitoring Devices

Artificial intelligence (AI) has brought lots of excitement to our day-to-day lives. Some examples are spam email detection, language translation, etc. Baby monitoring devices are being used to send video data of the baby to the caregiver’s smartphone. However, the automatic understanding of the data was not implemented in most of these devices. In this research, AI and image processing techniques were developed to automatically recognize unwanted situations that the baby was in. The monitoring device automatically detected: (a) whether the baby’s face was covered due to sleeping on the stomach; (b) whether the baby threw off the blanket from the body; (c) whether the baby was moving frequently; (d) whether the baby’s eyes were opened due to awakening. The device sent notifications and generated alerts to the caregiver’s smartphone whenever one or more of these situations occurred. Thus, the caregivers were not required to monitor the baby at regular intervals. They were notified when their attention was required. The device was developed using NVIDIA’s Jetson Nano microcontroller. A night vision camera and Wi-Fi connectivity were interfaced. Deep learning models for pose detection, face and landmark detection were implemented in the microcontroller. A prototype of the monitoring device and the smartphone app were developed and tested successfully for different scenarios. Compared with general baby monitors, the proposed device gives more peace of mind to the caregivers by automatically detecting un-wanted situations.

Steinernema borjomiense n. sp. (Rhabditida: Steinernematidae), a new entomopathogenic nematode from Georgia

Nematology ◽  
2018 ◽  
Vol 20 (7) ◽  
pp. 653-669 ◽  
Author(s):  
Oleg Gorgadze ◽  
Elena Fanelli ◽  
Manana Lortkhipanidze ◽  
Alberto Troccoli ◽  
Medea Burjanadze ◽  
...  
Keyword(s):  
New Species ◽  
18S Rrna ◽  
Entomopathogenic Nematode ◽  
Phylogenetic Analyses ◽  
Tail Length ◽  
Morphological Characters ◽  
18S Rrna Gene ◽  
The Body ◽  
Rrna Gene ◽  
A New Species

Summary A new species of entomopathogenic nematode, Steinernema borjomiense n. sp., was isolated from the body of the host insect, Oryctes nasicornis (Coleoptera: Scarabaeidae), in Georgia, in the territory of Borjomi-Kharagauli. Morphological characters indicate that the new species is closely related to species of the feltiae-group. The infective juveniles are characterised by the following morphological characters: body length of 879 (777-989) μm, distance between the head and excretory pore = 72 (62-80) μm, pharynx length = 132 (122-142) μm, tail length = 70 (60-80) μm, ratio a = 26.3 (23.0-29.3), H% = 45 (40-51), D% = 54 (47-59), E% = 102 (95-115), and lateral fields consisting of seven ridges (eight incisures) at mid-body. Steinernema borjomiense n. sp. was molecularly characterised by sequencing three ribosomal regions (the ITS, the D2-D3 expansion domains and the 18S rRNA gene) and the mitochondrial COI gene. Phylogenetic analyses revealed that S. borjomiense n. sp. differs from all other known species of Steinernema and is a member of the monticolum-group.

Growth performance, correlation and regression estimates of seven-chicken strains in South-Western Nigeria

2020 ◽  
Vol 45 (2) ◽  
pp. 40-48
Author(s):  
A. J. Atansuyi ◽  
U. C. Ihendu ◽  
C. A. Chineke
Keyword(s):  
Body Weight ◽  
Growth Performance ◽  
Correlation Coefficients ◽  
Tail Length ◽  
Experimental Period ◽  
The Body ◽  
Coefficient Of Determination ◽  
Indigenous Chicken ◽  
Randomized Design ◽  
Study Results

This study was conducted to determine the growth performance, correlation and regression estimates of seven-chicken strains in South-western Nigeria using a total of 300 day-old chicks. The birds were divided into seven groups based on their strain. The seven strains are Normal feather (NF), Fulani ecotype (FE), Frizzle feather (FF), naked neck (NN) and Transylvania indigenous strains while Hubbard and Marshal were meat-type exotic chickens. There were forty- five (45) unsexed day-old chicks in each strain except the Frizzle feather that were 30 in number. Completely randomized design (CRD) was used for the trial that lasted for 8 weeks. The birds were fed experimental diets ad libitum throughout the period of the study. Results showed that there were significant differences (p<0.05) in the initial and final weights of the birds. It was observed that exotic strains weighed heavier (3569.73gHB) than their indigenous counterparts (1391.11gNF). However, the Fulani ecotype weighed heaviest (1840.99g) among Nigeria indigenous strains during the experimental period. This showed that FE strains are generally heavy breed chicken and could be incorporated into a meat producing indigenous chicken if improved upon. The result of the correlation coefficients showed that a very strong, positive and highly significant (P<0.001) relationship existed between body weights and linear body measurements as most of the values are (>0.40). All the body parameter examined had significant (p<0.01) and direct relationship with the body weight. Shoulder-to-tail length (STL) had the highest coefficient of 0.98.The high correlation estimates obtained in this study could be as a result of pleiotropy, heterozygosity or linkage of genes in the birds. The three functions were highly significant (p<0.05) for all the parameters studied. This shows that the functions well described the parameters. On the basis of coefficient of determination (R ), the body weight of poultry birds at any age can be predicted most accurately with BRG using cubic function.

Acetyl L-Carnitine Slows Decline in Younger Patients With Alzheimer's Disease: A Reanalysis of a Double-Blind, Placebo-Controlled Study Using the Trilinear Approach

1998 ◽  
Vol 10 (2) ◽  
pp. 193-203 ◽  
Author(s):  
John O. Brooks ◽  
Jerome A. Yesavage ◽  
Angelico Carta ◽  
Daniele Bravi
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Average Rate ◽  
The United States ◽  
Rate Of Change ◽  
Disease Assessment ◽  
Controlled Study ◽  
Double Blind ◽  
Parallel Group ◽  
Longitudinal Effects

Objectives: To assess the longitudinal effects of acetyl-L-carnitine (ALC) on patients diagnosed with Alzheimer's disease. Design: Longitudinal, double-blind, parallel-group, placebocontrolled. Setting: Twenty-four outpatient sites across the United States. Participants: A total of 334 subjects diagnosed with probable Alzheimer's disease by NINCDS-ADRDA criteria. These data were originally reported by Thal and colleagues (1996). Measurements: Cognitive subscale of the Alzheimer Disease Assessment Scale (ADAS) given every 3 months for 1 year. Results: The average rate of change was estimated using the trilinear approach, which allows for periods of both change and stability. Both the ALC group and the placebo group exhibited the same mean rate of change on the ADAS (0.68 points/month). However, a multiple regression analysis revealed a statistically significant Age × Drug interaction characterized by younger subjects benefiting more from ALC treatment than older subjects. Further analyses suggested that the optimal, though not statistically significant, cutpoint for ALC benefit was 61 years of age. Conclusions: ALC slows the progression of Alzheimer's disease in younger subjects, and the use of the trilinear approach to estimate the average rate of change may prove valuable in pharmacological trials.

scholarly journals Comparison of Deep Neural Network Models and Effectiveness of EMG Signal Feature Value for Estimating Dorsiflexion

Electronics ◽  
2021 ◽  
Vol 10 (22) ◽  
pp. 2767
Author(s):  
Muhammad Akmal Bin Mohammed Zaffir ◽  
Praveen Nuwantha ◽  
Daiki Arase ◽  
Keiko Sakurai ◽  
Hiroki Tamura
Keyword(s):  
Neural Network ◽  
Average Rate ◽  
Network Models ◽  
Rate Of Change ◽  
Estimation Accuracy ◽  
Neural Network Models ◽  
Emg Signal ◽  
Minimum Number ◽  
Deep Learning Network ◽  
Simple Network

(1) Background: Robotic ankle–foot orthoses (AFO) are often used for gait rehabilitation. Our research focuses on the design and development of a robotic AFO with minimum number of sensor inputs. However, this leads to degradation of gait estimation accuracy. (2) Methods: To prevent degradation of accuracy, we compared a few neural network models in order to determine the best network when only two input channels are being used. Further, the EMG signal feature value of average rate of change was used as input. (3) Results: LSTM showed the highest accuracy. However, MLP with a small number of hidden layers showed results similar to LSTM. Moreover, the accuracy for all models, with the exception of LSTM for one subject (SD), increased with the addition of feature value (average rate of change) as input. (4) Conclusions: In conclusion, time-series networks work best with a small number of sensor inputs. However, depending on the optimizer being used, even a simple network can outrun a deep learning network. Furthermore, our results show that applying EMG signal feature value as an input tends to increase the estimation accuracy of the network.

scholarly journals Genotype, gestation length, season, parity and sex effects on growth traits of two rabbit breeds and their crosses

2014 ◽  
Vol 30 (4) ◽  
pp. 717-729 ◽  
Author(s):  
S.S.A. Egena ◽  
G.N. Akpa ◽  
I.C. Alemede ◽  
A. Aremu
Keyword(s):  
Growth Traits ◽  
Tail Length ◽  
The Body ◽  
Gestation Length ◽  
Body Measurements ◽  
Season Of Birth ◽  
Trunk Length ◽  
Body Dimensions ◽  
Sex Effects ◽  
Foundation Stock

One hundred and thirty rabbits were used to evaluate the effect of genotype, gestation length, season, parity and sex on growth traits of two breeds of rabbit and their crosses. The rabbit used for the experiment were breeds of the New Zealand White (NZW) and Chinchilla (CH) breed. Six breeding bucks (three/breed) and eighteen breeding does (nine/breed) served as the foundation stock. Traits measured include: body weight (BW), nose to shoulder length (NTS), shoulder to tail length (STL), heart girth (HG), trunk length (TL) and length of ear (LE). Results revealed that, BW of the rabbits were influenced (p<0.05) by genotype, gestation length and season. CH x (CH x NZW) progenies had better BW at 35-d and 49-d of age while NZW x CH progenies had better BW at 21-d of age. Kittens born late (32-34 days) had better BW at 21-d, 35-d and 49-d while kittens kindled during early dry season had better BW at 21-d, 35-d and 49-d. Genotype affected (p<0.05) all the body measurements at 21-d, 35-d and 49-d. Gestation length affected (p<0.05) all the body measurements except for NTS at 21-d and HG at 49-d respectively. Season of birth also influenced (p<0.05) all the body measurements except for LE 21-d. Parity and sex had no effect (p>0.05) on BW, NTS, STL, HG, TL and LE. It was concluded that genotype, gestation length and season influenced BW and body dimensions of the two breeds of rabbit and their crosses while parity and sex had no effect.

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