scholarly journals A unified theory for the energy cost of legged locomotion

2016 ◽  
Vol 12 (2) ◽  
pp. 20150935 ◽  
Author(s):  
Herman Pontzer
Keyword(s):  
Energy Cost ◽  
Muscle Metabolism ◽  
Legged Locomotion ◽  
Muscle Physiology ◽  
Unified Theory ◽  
Arc Model ◽  
Ranging Behaviour ◽  
Wide Range ◽  
Locomotor Energetics ◽  
Level Running

Small animals are remarkably efficient climbers but comparatively poor runners, a well-established phenomenon in locomotor energetics that drives size-related differences in locomotor ecology yet remains poorly understood. Here, I derive the energy cost of legged locomotion from two complementary components of muscle metabolism, Activation–Relaxation and Cross-bridge cycling. A mathematical model incorporating these costs explains observed patterns of locomotor cost both within and between species, across a broad range of animals (insects to ungulates), for a wide range of substrate slopes including level running and vertical climbing. This ARC model unifies work- and force-based models for locomotor cost and integrates whole-organism locomotor cost with cellular muscle physiology, creating a predictive framework for investigating evolutionary and ecological pressures shaping limb design and ranging behaviour.

Précis ofUnified theories of cognition

1992 ◽  
Vol 15 (3) ◽  
pp. 425-437 ◽  
Author(s):  
Allen Newell
Keyword(s):  
Cognitive Science ◽  
Full Range ◽  
Cognitive Architecture ◽  
Convincing Evidence ◽  
Syllogistic Reasoning ◽  
Human Cognition ◽  
Unified Theory ◽  
Theoretical Concepts ◽  
Wide Range ◽  
Unified Theories

AbstractThe book presents the case that cognitive science should turn its attention to developing theories of human cognition that cover the full range of human perceptual, cognitive, and action phenomena. Cognitive science has now produced a massive number of high-quality regularities with many microtheories that reveal important mechanisms. The need for integration is pressing and will continue to increase. Equally important, cognitive science now has the theoretical concepts and tools to support serious attempts at unified theories. The argument is made entirely by presenting an exemplar unified theory of cognition both to show what a real unified theory would be like and to provide convincing evidence that such theories are feasible. The exemplar is SOAR, a cognitive architecture, which is realized as a software system. After a detailed discussion of the architecture and its properties, with its relation to the constraints on cognition in the real world and to existing ideas in cognitive science, SOAR is used as theory for a wide range of cognitive phenomena: immediate responses (stimulus-response compatibility and the Sternberg phenomena); discrete motor skills (transcription typing); memory and learning (episodic memory and the acquisition of skill through practice); problem solving (cryptarithmetic puzzles and syllogistic reasoning); language (sentence verification and taking instructions); and development (transitions in the balance beam task). The treatments vary in depth and adequacy, but they clearly reveal a single, highly specific, operational theory that works over the entire range of human cognition, SOAR is presented as an exemplar unified theory, not as the sole candidate. Cognitive science is not ready yet for a single theory – there must be multiple attempts. But cognitive science must begin to work toward such unified theories.

Functional implications of supercontracting muscle in the chameleon tongue retractors

2001 ◽  
Vol 204 (21) ◽  
pp. 3621-3627 ◽  
Author(s):  
Anthony Herrel ◽  
Jay J. Meyers ◽  
Peter Aerts ◽  
Kiisa C. Nishikawa
Keyword(s):  
Prey Capture ◽  
Three Dimensional ◽  
Force Production ◽  
Retractor Muscle ◽  
Muscle Physiology ◽  
Large Prey ◽  
Wide Range ◽  
Ambush Predators ◽  
Full Body

SUMMARYChameleons capture prey items using a ballistic tongue projection mechanism that is unique among lizards. During prey capture, the tongue can be projected up to two full body lengths and may extend up to 600 % of its resting length. Being ambush predators, chameleons eat infrequently and take relatively large prey. The extreme tongue elongation (sixfold) and the need to be able to retract fairly heavy prey at any given distance from the mouth are likely to place constraints on the tongue retractor muscles. The data examined here show that in vivo retractor force production is almost constant for a wide range of projection distances. An examination of muscle physiology and of the ultrastructure of the tongue retractor muscle shows that this is the result (i) of active hyoid retraction, (ii) of large muscle filament overlap at maximal tongue extension and (iii) of the supercontractile properties of the tongue retractor muscles. We suggest that the chameleon tongue retractor muscles may have evolved supercontractile properties to enable a substantial force to be produced over a wide range of tongue projection distances. This enables chameleons successfully to retract even large prey from a variety of distances in their complex three-dimensional habitat.

scholarly journals A REVIEW ON A NOVEL APPROACH FOR DATA COLLECTION IN WSN

2017 ◽  
Vol 16 (3) ◽  
pp. 6213-6218
Author(s):  
Ramandeep Kaur ◽  
Dinesh Kumar
Keyword(s):  
Sensor Network ◽  
Data Aggregation ◽  
Energy Cost ◽  
Sensor Nodes ◽  
Wireless Sensor ◽  
Threshold Values ◽  
Novel Approach ◽  
Wide Range ◽  
Network Application ◽  
Soft Threshold

Wireless sensor networks have become increasingly popular due to their wide range of application. Clustering sensor nodes organizing them hierarchically have proven to be an effective method to provide better data aggregation and scalability for the sensor network while conserving limited energy. Minimizing the energy consumption of a wireless sensor network application is crucial for effective realization of the intended application in terms of cost, lifetime, and functionality. However, the minimizing task is hardly possible as no overall energy cost function is available for optimization. In this paper, we have proposed a modified alogirthm of leach where hard and soft threshold values will be applied for improving the overall throughput and network lifetime.

Energy Cost of Running in Well-Trained Athletes: Toward Slope-Dependent Factors

2021 ◽  
pp. 1-9
Author(s):  
Marcel Lemire ◽  
Romain Remetter ◽  
Thomas J. Hureau ◽  
Bernard Geny ◽  
Evelyne Lonsdorfer ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Lower Limb ◽  
Energy Cost ◽  
Cardiovascular Responses ◽  
Maximum Oxygen Consumption ◽  
Step Frequency ◽  
Physiological Factors ◽  
Vertical Stiffness ◽  
Energy Cost Of Running ◽  
Level Running

Purpose: This study aimed to determine the contribution of metabolic, cardiopulmonary, neuromuscular, and biomechanical factors to the energy cost (ECR) of graded running in well-trained runners. Methods: Eight men who were well-trained trail runners (age: 29 [10] y, mean [SD]; maximum oxygen consumption: 68.0 [6.4] mL·min−1·kg−1) completed maximal isometric evaluations of lower limb extensor muscles and 3 randomized trials on a treadmill to determine their metabolic and cardiovascular responses and running gait kinematics during downhill (DR: −15% slope), level (0%), and uphill running (UR: 15%) performed at similar O2 uptake (approximately 60% maximum oxygen consumption). Results: Despite similar O2 demand, ECR was lower in DR versus level running versus UR (2.5 [0.2] vs 3.6 [0.2] vs 7.9 [0.5] J·kg−1·m−1, respectively; all P < .001). Energy cost of running was correlated between DR and level running conditions only (r2 = .63; P = .018). Importantly, while ECR was correlated with heart rate, cardiac output, and arteriovenous O2 difference in UR (all r2 > .50; P < .05), ECR was correlated with lower limb vertical stiffness, ground contact time, stride length, and step frequency in DR (all r2 > .58; P < .05). Lower limb isometric extension torques were not related to ECR whatever the slope. Conclusion: The determining physiological factors of ECR might be slope specific, mainly metabolic and cardiovascular in UR versus mainly neuromuscular and mechanical in DR. This possible slope specificity of ECR during incline running opens the way for the implementation of differentiated physiological evaluations and training strategies to optimize performance in well-trained trail runners.

scholarly journals Investigating human skeletal muscle physiology with unilateral exercise models: when one limb is more powerful than two

2017 ◽  
Vol 42 (6) ◽  
pp. 563-570 ◽  
Author(s):  
Martin J. MacInnis ◽  
Chris McGlory ◽  
Martin J. Gibala ◽  
Stuart M. Phillips
Keyword(s):  
Skeletal Muscle ◽  
Repeated Measures ◽  
Statistical Power ◽  
Human Skeletal Muscle ◽  
Capillary Density ◽  
Muscle Physiology ◽  
Repeated Measures Design ◽  
Confounding Variables ◽  
Direct Sampling ◽  
Wide Range

Direct sampling of human skeletal muscle using the needle biopsy technique can facilitate insight into the biochemical and histological responses resulting from changes in exercise or feeding. However, the muscle biopsy procedure is invasive, and analyses are often expensive, which places pragmatic restraints on sample sizes. The unilateral exercise model can serve to increase statistical power and reduce the time and cost of a study. With this approach, 2 limbs of a participant are randomized to 1 of 2 treatments that can be applied almost concurrently or sequentially depending on the nature of the intervention. Similar to a typical repeated measures design, comparisons are made within participants, which increases statistical power by reducing the amount of between-person variability. A washout period is often unnecessary, reducing the time needed to complete the experiment and the influence of potential confounding variables such as habitual diet, activity, and sleep. Variations of the unilateral exercise model have been employed to investigate the influence of exercise, diet, and the interaction between the 2, on a wide range of variables including mitochondrial content, capillary density, and skeletal muscle hypertrophy. Like any model, unilateral exercise has some limitations: it cannot be used to study variables that potentially transfer across limbs, and it is generally limited to exercises that can be performed in pairs of treatments. Where appropriate, however, the unilateral exercise model can yield robust, well-controlled investigations of skeletal muscle responses to a wide range of interventions and conditions including exercise, dietary manipulation, and disuse or immobilization.

Special Issue on Dynamically and Biologically Inspired Legged Locomotion

2017 ◽  
Vol 29 (3) ◽  
pp. 455-455
Author(s):  
Tetsuya Kinugasa ◽  
◽  
Koh Hosoda ◽  
Masatsugu Iribe ◽  
Fumihiko Asano ◽  
...  
Keyword(s):  
Design Method ◽  
Joint Stiffness ◽  
Legged Locomotion ◽  
The Body ◽  
Biological Characteristics ◽  
Dynamic Walking ◽  
Special Issue ◽  
Biologically Inspired ◽  
Passive Dynamic Walking ◽  
Wide Range

Legged locomotion, including walking, running, turning, and jumping, strongly depends on the dynamics and biological characteristics of the body involved. Gait patterns and energy efficiency, for example, are known to be greatly affected by not only travel velocity and ground contact conditions but also by body configuration, such as joint stiffness and coordination, as well as foot sole shape. To understand legged locomotion principles, we must clarify how the body’s dynamic and biological characteristics affect locomotion. Effort must also be made to incorporate these characteristics inventively to improve locomotion performance, such as robustness, adaptability, and efficiency, which further refine the legged locomotion. This special issue on “Dynamically and Biologically Inspired Legged Locomotion,” studies on legged locomotion based on dynamic and biological characteristics, covers a wide range of themes, such as a rimless wheel, a design method for a biped based on passive dynamic walking, the analysis of biped locomotion based on passive dynamic walking and dynamically inspired walking, an analysis of gait generation for a triped robot, and quadruped locomotion with a flexible trunk. Since there are interesting papers on legged robots with different numbers of legs, we basically organized the papers based on the number of legs. Studies on “Dynamically and Biologically Inspired Legged Locomotion” are expected to not only realize and improve legged locomotion as engineering, but also to reveal the locomotion mechanism of various creatures as science.

Torso Stabilization Reduces the Metabolic Cost of Producing Cycling Power

2005 ◽  
Vol 30 (4) ◽  
pp. 433-441 ◽  
Author(s):  
John McDaniel ◽  
Andrew Subudhi ◽  
James C. Martin
Keyword(s):  
Ventilatory Threshold ◽  
Muscle Metabolism ◽  
Control Unit ◽  
Metabolic Cost ◽  
Cycle Ergometer ◽  
Whole Body ◽  
Strongly Correlated ◽  
Wide Range ◽  
Static Contraction ◽  
Power Outputs

Many researchers have used cycling exercise to evaluate muscle metabolism. Inherent in such studies is an assumption that changes in whole-body respiration are due solely to respiration at the working muscle. Some researchers, however, have speculated that the metabolic cost of torso stabilization may contribute to the metabolic cost of cycling. Therefore, our primary purpose was to determine whether a torso stabilization device would reduce the metabolic cost of producing cycling power. Our secondary purpose was to determine the validity of the ergometer used in this study. Nine male cyclists cycled on a Velotron cycle ergometer at mechanical power outputs intended to elicit 50, 75, and 100% of their ventilatory threshold at 40, 60, and 80 rpm, with and without torso stabilization. Power was controlled by the Velotron in iso-power mode and measured with an SRM powermeter. We determined metabolic cost by indirect calorimetery and recorded power output. Torso stabilization significantly reduced metabolic cost of producing submaximal power (1%), and reduction tended to be greatest at the lower pedaling rates where pedaling force was greatest (1.6% at 40 rpm, 1.2% at 60 rpm, 0.2% at 80 rpm). Power, measured with the SRM powermeter, was strongly correlated with that specified to the Velotron ergometer control unit (R2 > 0.99). We conclude that muscular contractions associated with torso stabilization elicit significant metabolic costs, which tend to be greatest at low pedaling rates. Researchers who intend to make precise inferences regarding metabolism in the working muscles of the legs may wish to provide torso stabilization as a means of reducing variability, particularly when comparing metabolic data across a wide range of pedaling rates. Key words: efficiency, economy, metabolism, static contraction, work

scholarly journals A Modified Leach Algorithm Using Hard and Soft Threshold in Wireless Sensor Network: A Review

2015 ◽  
Vol 14 (10) ◽  
pp. 6142-6146
Author(s):  
Gurpreet Kaur ◽  
Vishal Arora
Keyword(s):  
Wireless Sensor Network ◽  
Sensor Network ◽  
Data Aggregation ◽  
Energy Cost ◽  
Sensor Nodes ◽  
Wireless Sensor ◽  
Threshold Values ◽  
Wide Range ◽  
Network Application ◽  
Soft Threshold

Wireless sensor networks have become increasingly popular due to their wide range of application. Clustering sensor nodes organizing them hierarchically have proven to be an effective method to provide better data aggregation and scalability for the sensor network while conserving limited energy. Minimizing the energy consumption of a wireless sensor network application is crucial for effective realization of the intended application in terms of cost, lifetime, and functionality. However, the minimizing task is hardly possible as no overall energy cost function is available for optimization. In this paper, we have proposed a modified alogirthm of leach where hard and soft threshold values will be applied for improving the overall throughput and network lifetime.

scholarly journals The quest for a unified theory on biomechanical palm risk assessment through theoretical analysis and observation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Peter Sterken
Keyword(s):  
Mathematical Model ◽  
Risk Assessment ◽  
Wind Speed ◽  
Theoretical Analysis ◽  
Mechanical Behaviour ◽  
Beam Theory ◽  
Wind Loading ◽  
Unified Theory ◽  
Simple Mathematical Model ◽  
Wide Range

AbstractSeveral methodologies related to the biomechanical risk assessment and the uprooting and breaking potential of palms are reviewed and evaluated in this study. Also a simple mathematical model was designed, to simulate the results of critical wind speed predictions for a tall coconut palm by using classic beam theory and Brazier buckling. First, the review presents arguments that assess the applicability of some influential claims and tree and palm risk assessment methods that have been amply marketed in the last 20 years. Then, the analysis goes beyond the classical procedures and theories that have influenced the arboricultural industry and related press so far. And afterwards, rationale behind several postulated ideas are presented, that are hoped to be fruitful in the path towards a new biomechanical theory for the biomechanical risk assessment of palms. The postulated model envisages the palm stem as a viscoelastic and hollow cylinder that is not only prone to buckling, ovalization and kinking, but also fatigue, shear, splitting and crack propagation. This envisaging was also the main reason why simple Brazier buckling formulation was experimentally applied to simulate the breaking risk of a cocostem. This study also enables a better understanding of the wide range of factors that may influence the mechanical behaviour of trees and palms under (wind) loading.

scholarly journals More Arrows in the Ancient DNA Quiver: Use of Paleoepigenomes and Paleomicrobiomes to Investigate Animal Adaptation to Environment

2019 ◽  
Vol 37 (2) ◽  
pp. 307-319 ◽  
Author(s):  
Yichen Liu ◽  
Laura S Weyrich ◽  
Bastien Llamas
Keyword(s):  
Molecular Evolution ◽  
Ancient Dna ◽  
Empirical Data ◽  
Genetic Factors ◽  
Experimental Studies ◽  
Modern Synthesis ◽  
Epigenetic Mechanisms ◽  
Unified Theory ◽  
Animal Evolution ◽  
Wide Range

Abstract Whether and how epigenetic mechanisms and the microbiome play a role in mammalian adaptation raised considerable attention and controversy, mainly because they have the potential to add new insights into the Modern Synthesis. Recent attempts to reconcile neo-Darwinism and neo-Lamarckism in a unified theory of molecular evolution give epigenetic mechanisms and microbiome a prominent role. However, supporting empirical data are still largely missing. Because experimental studies using extant animals can hardly be done over evolutionary timescales, we propose that advances in ancient DNA techniques provide a valid alternative. In this piece, we evaluate 1) the possible roles of epigenomes and microbiomes in animal adaptation, 2) advances in the retrieval of paleoepigenome and paleomicrobiome data using ancient DNA techniques, and 3) the plasticity of either and interactions between the epigenome and the microbiome, while emphasizing that it is essential to take both into account, as well as the underlying genetic factors that may confound the findings. We propose that advanced ancient DNA techniques should be applied to a wide range of past animals, so novel dynamics in animal evolution and adaption can be revealed.

Sign in / Sign up

Export Citation Format

Share Document