scholarly journals Dynamics and stability of directional jumps in the desert locust

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2481 ◽  
Author(s):  
Omer Gvirsman ◽  
Gabor Kosa ◽  
Amir Ayali
Keyword(s):  
Body Position ◽  
Careful Analysis ◽  
Muscle Physiology ◽  
Contact Points ◽  
Adult Locust ◽  
Angular Velocities ◽  
Dynamic Computer Simulation ◽  
Jumping Robot ◽  
Jump Trajectory ◽  
Flight Initiation

Locusts are known for their ability to jump large distances to avoid predation. The jump also serves to launch the adult locust into the air in order to initiate flight. Various aspects of this important behavior have been studied extensively, from muscle physiology and biomechanics, to the energy storage systems involved in powering the jump, and more. Less well understood are the mechanisms participating in control of the jump trajectory. Here we utilise video monitoring and careful analysis of experimental directional jumps by adult desert locusts, together with dynamic computer simulation, in order to understand how the locusts control the direction and elevation of the jump, the residual angular velocities resulting from the jump and the timing of flapping-flight initiation. Our study confirms and expands early findings regarding the instrumental role of the initial body position and orientation. Both real-jump video analysis and simulations based on our expanded dynamical model demonstrate that the initial body coordinates of position (relative to the hind-legs ground-contact points) are dominant in predicting the jumps’ azimuth and elevation angles. We also report a strong linear correlation between the jumps’ pitch-angular-velocity and flight initiation timing, such that head downwards rotations lead to earlier wing opening. In addition to offering important insights into the bio-mechanical principles of locust jumping and flight initiation, the findings from this study will be used in designing future prototypes of a bio-inspired miniature jumping robot that will be employed in animal behaviour studies and environmental monitoring applications.

Adaptation of the vestibulo-ocular reflex, subjective tilt, and motion sickness to head movements during short-radius centrifugation

2003 ◽  
Vol 13 (2-3) ◽  
pp. 65-77
Author(s):  
Laurence R. Young ◽  
Kathleen H. Sienko ◽  
Lisette E. Lyne ◽  
Heiko Hecht ◽  
Alan Natapoff
Keyword(s):  
Motion Sickness ◽  
Body Position ◽  
Rest Period ◽  
Vertical Axis ◽  
Head Movements ◽  
Whole Body ◽  
Slow Phase ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex ◽  
Angular Velocities

Head movements made while the whole body is rotating at unusually high angular velocities (here with supine body position about an earth-vertical axis) result in inappropriate eye movements, sensory illusions, disorientation, and frequently motion sickness. We investigated the acquisition and retention of sensory adaptation to cross-coupled components of the vestibulo-ocular reflex (VOR) by asking eight subjects to make headturns while being rotated at 23 rpm on two consecutive days, and again a week later. The dependent measures were inappropriate vertical VOR, subjective tilt, and motion sickness in response to 90° yaw out-of-plane head movements. Motion sickness was evaluated during and following exposure to rotation. Significant adaptation effects were found for the slow phase velocity of vertical nystagmus, the reported magnitude of the subjective tilt experienced during head turns, and motion-sickness scores. Retention of adaptation over a six-day rest period without rotation occurred, but was not complete for all measures. Adaptation of VOR was fully maintained while subjective tilt was only partially maintained and motion-sickness scores continued to decrease. Practical implications of these findings are discussed with particular emphasis on artificial gravity, which could be produced in weightlessness by means of a short-radius (2 m) rotator.

Study of Orientation Control for a Wheeled Jumping Robot in the Flight Phase of Motion

2019 ◽  
Vol 20 (4) ◽  
pp. 236-243 ◽  
Author(s):  
S. F. Jatsun ◽  
L. Yu. Vorochaeva ◽  
S. I. Savin
Keyword(s):  
Control System ◽  
Piecewise Linear ◽  
The Body ◽  
Linear Functions ◽  
Piecewise Linear Functions ◽  
Supporting Surface ◽  
Flight Phase ◽  
Angular Velocities ◽  
Jumping Robot ◽  
The Moment

The work studies the flight phase (a part of jumping motion) of a jumping robot. The robot consists of the body with wheeled base and a jump booster module installed in the body. The jump booster module allows the robot to accelerate in a given direction up to a predetermined speed, allowing to control the velocity of the robot at the moment when it breaks contact with the supporting surface. The goal of this study is to develop a control system for the robot’s wheels, allowing to use their inertial properties to control the robot orientation at the moment of landing. This is achieved by controlling the wheels’ orientation throughout the duration of the motion. The goal of controlling the orientation of the robot at the moment of landing is to be able to land on all four wheels and avoid tipping over. The paper studies the supporting surfaces (from which the robot jumps and to which the robot lands) described by piecewise linear functions, including a horizontal and slopped linear sub-functions. In this work, four types of supporting surfaces were distinguished, which the distinction based on the slope of the mentioned about sub-function. Another varying parameter is the point where two sub-functions connect. For the purpose of this study a kinematic and dynamic model of the robot were developed, and a control system design was proposed. The proposed control system includes a trajectory planner that allows to plan the robot’s motion resulting in the desired orientation of the robot’s body at the moment of landing. This problem was formulated as an optimization problem. Simulation results showed the dependencies between the three supporting surface parameters (two angles describing linear sub-functions and the point where the sub-functions intersect) and the duration of the robot flight, the achieved velocities of the robot’s wheels and required motor torques. The influence of those parameters on the maximal and minimal values of the wheels’ angular velocities achieved during the flight were demonstrated. This could be used in designing this type of robots, in particular it could help to set specifications for the robot’s wheel motors.

Analysis of Dark-Field Images of Disordered Materials

1972 ◽  
Vol 30 ◽  
pp. 560-561
Author(s):  
J. M. Cowley
Keyword(s):  
Amorphous Materials ◽  
Careful Analysis ◽  
Dark Field ◽  
Minimum Diameter ◽  
Statistical Fluctuations ◽  
Bright Spots ◽  
Sufficient Detail ◽  
Random Arrangement ◽  
Diffraction Patterns ◽  
Imaging Conditions

Recently a number of authors have reported detail in dark-field images obtained from diffuse-scattering regions of electron diffraction patterns. Bright spots in images from short-range order diffuse peaks of disordered binary alloys have been interpreted as evidence for the existence of microdomains of ordered lattice or of segragated clusters of one component. Spotty contrast in dark field images of near-amorphous materials has been interpreted as evidence for the existense of microcrystals. Without a careful analysis of the imaging conditions such conclusions may be invalid. Usually the conditions of the experiment have not been specified in sufficient detail to allow evaluation of the conclusions.Elementary considerations show that even for a completely random arrangement of atoms the statistical fluctuations of density will give a spotty contrast with spots of minimum diameter determined by the dark field aperture size and other factors influencing the minimum resolvable distance under darkfield imaging conditions, including fluctuations and drift over long exposure times (resolution usually 10Å or more).

Case Exercise: Biomechanics in Rearend Motor Vehicle Collisions

2007 ◽  
Vol 12 (3) ◽  
pp. 4-7
Author(s):  
Charles N. Brooks ◽  
Christopher R. Brigham
Keyword(s):  
Motor Vehicle ◽  
Body Position ◽  
Motor Vehicle Collisions ◽  
Time Curve ◽  
Vehicle Collisions ◽  
Need For Treatment ◽  
Multiple Factors ◽  
Bodily Injury ◽  
Vehicle Collision ◽  
Physical Findings

Abstract Multiple factors determine the likelihood, type, and severity of bodily injury following a motor vehicle collision and, in turn, influence the need for treatment, extent of disability, and likelihood of permanent impairment. Among the most important factors is the change in velocity due to an impact (Δv). Other factors include the individual's strength and elasticity, body position at the time of impact, awareness of the impending impact (ie, opportunity to brace, guard, or contract muscles before an impact), and effects of braking. Because Δv is the area under the acceleration vs time curve, it combines force and duration and is a useful way to quantify impact severity. The article includes a table showing the results of a literature review that concluded, “the consensus of human subject research conducted to date is that a single exposure to a rear-end impact with a Δv of 5 mph or less is unlikely to result in injury” in most healthy, restrained occupants. Because velocity incorporates direction as well as speed, a vehicular occupant is less likely to be injured in a rear impact than when struck from the side. Evaluators must consider multiple factors, including the occupant's pre-existing physical and psychosocial status, the mechanism and magnitude of the collision, and a variety of biomechanical variables. Recommendations based solely on patient history and physical findings (and, perhaps, imaging studies) may be ill-informed.

Left Ventricular Hypertrophy

2014 ◽  
Vol 19 (2) ◽  
pp. 11-15
Author(s):  
Steven L. Demeter
Keyword(s):  
Risk Factors ◽  
Left Ventricular Hypertrophy ◽  
Ventricular Hypertrophy ◽  
Left Ventricular Mass Index ◽  
Medical Science ◽  
Careful Analysis ◽  
Left Ventricular ◽  
Hypertensive Disease ◽  
Accurate Analysis ◽  
Clear Explanation

Abstract The fourth, fifth, and sixth editions of the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides) use left ventricular hypertrophy (LVH) as a variable to determine impairment caused by hypertensive disease. The issue of LVH, as assessed echocardiographically, is a prime example of medical science being at odds with legal jurisprudence. Some legislatures have allowed any cause of LVH in a hypertensive individual to be an allowed manifestation of hypertensive changes. This situation has arisen because a physician can never say that no component of LVH was not caused by the hypertension, even in an individual with a cardiomyopathy or valvular disorder. This article recommends that evaluators consider three points: if the cause of the LVH is hypertension, is the examinee at maximum medical improvement; is the LVH caused by hypertension or another factor; and, if apportionment is allowed, then a careful analysis of the risk factors for other disorders associated with LVH is necessary. The left ventricular mass index should be present in the echocardiogram report and can guide the interpretation of the alleged LVH; if not present, it should be requested because it facilitates a more accurate analysis. Further, if the cause of the LVH is more likely independent of the hypertension, then careful reasoning and an explanation should be included in the impairment report. If hypertension is only a partial cause, a reasoned analysis and clear explanation of the apportionment are required.

EFEKTIFITAS KONSELING LAKTASI PADA IBU HAMIL TRIMESTER III TERHADAP PELAKSANAAN MENYUSUI

2019 ◽  
Vol 11 (1) ◽  
pp. 41-50
Author(s):  
Heni Purwaningsih ◽  
Umi Aniroh ◽  
Eko Mardiyaningsih
Keyword(s):  
Mortality Rate ◽  
Pregnant Women ◽  
Body Position ◽  
Development Program ◽  
Optimal Growth ◽  
Infant Mortality Rate ◽  
P Value ◽  
Time Data ◽  
Emotional Bonding ◽  
Post Test

Program pembangunan kesehatan di Indonesia masih berfokus pada upaya peningkatan derajat kesehatan ibu dan anak terutama pada masa prenatal. Hal ini disebabkan masih tingginya Angka Kematian Ibu (AKI) dan Angka Kematian Bayi (AKB). ASI yang diberikan sejak usia dini dan dilanjutkan dengan ASI eksklusif selama 6 bulan dapat menurunkan angka kesakitan dan angka kematian bayi serta meningkatkan tumbuh kembang bayi secara optimal.  Penelitian ini bertujuan untuk mengetahui efektifitas pemberian konseling laktasi terhadap pelaksanaan menyusui pada ibu hamil trimester III. Desain penelitian menggunakan quasi eksperimen dengan rancangan One Group Pre-test dan  Post-test Desain. Populasi dalam penelitian ini adalah ibu hamil trimester III dan sampel yang diambil adalah 18 ibu hamil. Alat penggumpulan data menggunakan lembar observasi BREAST (body position, respons, emotional bonding, anatomy dan sucking time). Analisis data menggunakan wilcoxon.Hasil penelitian didapatkan pelaksanaan menyusui sebelum dilakukan konseling laktasi dalam kategori kurang (72,2%) sedangkan pelaksanaan menyusui setelah dilakukan konseling laktasi (77,8%) dalam kategori baik. Konseling laktasi efektif dilakukan untuk meningkatkan pelaksanaan menyusui denganp-value 0,003 (p<0,005).Konseling laktasi seharusnya diberikan pada masa prenatal sehingga pada saat postpartum, ibu sudah mampu memberikan asi secara maksimal. Pendampingan terhadap ibu hamil juga berperan dalam pelaksanaan pemberian ASI.   Kata kunci : Konseling laktasi, ASI, pelaksanaan menyusui   THE EFFECTIVENESS OF LACTATION COUNSELING IN THE 3rd TRIMESTER PREGNANT WOMEN ON BREASTFEEDING IMPLEMENTATION   ABSTRACT Indonesia's health development program still focuses on improving mother and child health, especially at the prenatal stage. It is due to the high maternal mortality rate (MMR) and Infant Mortality Rate (IMR). Breastmilk given from an early age and continued with exclusive breastfeeding for six months can reduce infants morbidity and mortality rate and increase their optimal growth. The purpose is to investigate the effectiveness of lactation counseling to the implementation of breastfeeding in third-trimester. The study design used quasi experiments with one group pre-test and post-test. Population was the 3rd-trimester pregnant mothers, and the samples were 18 mothers. The data collection tool used BREAST observation sheets (body position, response, emotional bonding, anatomy and sucking time). Data analysis used Wilcoxon. The result of the research shows that breastfeeding before lactation counseling is in less category (72,2%) while breastfeeding after lactation counseling (77,8%) is in a goodcategory. Effective lactation counseling is performed to improve the implementation of breastfeeding with p-value 0.003 (p <0.005). Lactation counseling should be given during the prenatal period so that at the time of postpartum, the mother has been able to give breastmilk maximally. Mentoring for pregnant women also plays a role in the implementation of breastfeeding Keywords: lactation counseling, breast milk, breastfeeding implementation

Lack of Tenderness: The Main Culprit for the Relationship between Husband and Wife in Lady Chatterley’s Lover

2017 ◽  
Keyword(s):  
Careful Analysis ◽  
Physical Distance ◽  
Human Society ◽  
Human Relationships ◽  
Main Culprit ◽  
Industrial Civilization ◽  
Lady Chatterley's Lover ◽  
The Relationship ◽  
Winter Hibernation ◽  
Husband And Wife

This article presents the case of Chatterley and Clifford, the two main characters in Lady Chatterley’s Lover, to consider tenderness a basic working emotion to shape human relationships. The lack of tenderness causes emotional as well as physical distance in relation, especially that of male-female’s relation. The first part of the article reviews tenderness. The second part reviews how tenderness and lack of tenderness affect a male-female relationship in the selected novel, Lady Chatterley’s Lover. On the basis of a careful analysis of Lady Chatterley’s Lover, the present writer tries to prove that the lack of tenderness is the main culprit for the broken relationship between husband and wife: a major one of the relations between man and woman in human society and mutual tenderness elicits people awakening to a new way of living in an exterior world that is uncracking after the long winter hibernation. Lawrence, through a revelation of Connie’s gradual awakening from tenderness, has made his utmost effort to explore possible solutions to harmonious androgyny between men and women so as to revitalize the distorted human nature caused by the industrial civilization. Key words: relationship, husband and wife, tenderness, main culprit, Connie

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