Related Experiment Video
Updated: Jul 11, 2026
08:50
The Mechanics of (Poro-)Elastic Contractile Actomyosin Networks As a Model System of the Cell Cytoskeleton
Published on: March 10, 2023
Time, transients and elasticity
C V Haridas1, Shripad Tuljapurkar
1Biological Sciences, Stanford University, Stanford, CA 94305, USA. charidas@stanford.edu
Ecology Letters
|September 22, 2007
Summary
Life history traits influence population growth rate elasticities by affecting population structure. Short-term elasticity depends on stable stage distribution and population momentum in non-stable populations.
Area of Science:
- Population Ecology
- Demography
- Mathematical Biology
Background:
- Understanding how life history traits impact population dynamics is crucial for ecological and conservation studies.
- Short-term elasticities quantify the immediate impact of demographic rate changes on population growth.
- Previous research has primarily focused on stable populations, leaving dynamics in non-stable populations less understood.
Purpose of the Study:
- To investigate the influence of life history on short-term population growth rate elasticities.
- To develop analytical methods for decomposing and calculating these elasticities.
- To explore the role of population structure, particularly stable stage distribution and population momentum, in elasticity calculations.
Main Methods:
- Decomposition of short-term elasticity into components related to population structure and vital rates.
- Derivation of exact analytical formulas for elasticity components.
- Analysis of elasticity in both stable and non-stable population structures.
Main Results:
- Short-term elasticity in stable populations is primarily determined by stable stage distribution (SSD) and reproductive value.
- In non-stable populations, elasticity is influenced by the projection of initial structure onto the SSD, equivalent to population momentum.
- The demographic damping rate dictates the convergence rate of short-term elasticity towards its limiting values.
Conclusions:
- Life history significantly shapes short-term population growth elasticities through its effects on population structure.
- Population momentum is a key factor in elasticity for non-stable populations, especially when certain life stages are underrepresented.
- The derived analytical framework provides a robust method for assessing demographic responses across diverse population states.
Related Concept Videos
01:12Elasticity
Elasticity is the ability of an object to withstand the effects of distortion and to return to its original size and shape once the forces causing deformation are removed. When an elastic material deforms under the action of an external force, it experiences internal resistance to the deformation. However, if no external force is applied, it returns to its original state.
The elasticity of an object can be described by a stress-strain curve, which represents the relationship between stress...
The elasticity of an object can be described by a stress-strain curve, which represents the relationship between stress...
01:24Transient and Steady-state Response
In control systems, test signals are essential for evaluating performance under various conditions. The ramp function is effective for systems undergoing gradual changes, while the step function is suitable for assessing systems facing sudden disturbances. For systems subjected to shock inputs, the impulse function is the most appropriate test signal.
These test signals are integral in designing control systems to exhibit two key performance aspects: transient response and steady-state response.
These test signals are integral in designing control systems to exhibit two key performance aspects: transient response and steady-state response.
01:28Atomic Nuclei: Types of Nuclear Relaxation
Nuclear relaxation restores the equilibrium population imbalance and can occur via spin–lattice or spin–spin mechanisms, which are first-order exponential decay processes.
In spin–lattice or longitudinal relaxation, the excited spins exchange energy with the surrounding lattice as they return to the lower energy level. Among several mechanisms that contribute to spin–lattice relaxation, magnetic dipolar interactions are significant. Here, the excited nucleus transfers energy to a nearby...
In spin–lattice or longitudinal relaxation, the excited spins exchange energy with the surrounding lattice as they return to the lower energy level. Among several mechanisms that contribute to spin–lattice relaxation, magnetic dipolar interactions are significant. Here, the excited nucleus transfers energy to a nearby...
01:18Residual Stresses in Bending
In the study of elastoplastic members subjected to bending moments, understanding the loading and unloading phases is crucial for assessing material behavior and structural integrity. During the loading phase, as the bending moment increases, the material initially responds elastically, adhering to Hooke's Law, where stress is directly proportional to strain. When the load exceeds the yield strength, plastic deformation occurs, resulting in permanent strain and deformation that remains even...
01:20Elasticity in Concrete
Upon subjecting concrete to moderate or high uniaxial compressive or tensile stresses, the strain response is non-linear relative to the stress applied. As the stress is removed, the resulting stress-strain curve deviates from the original path traced during loading, creating a hysteresis loop, indicative of the concrete's non-linear and non-elastic properties. Typically, a material's modulus of elasticity, which is a measure of the material's stiffness, is inferred from the linear portion of...
01:07Static Equilibrium - II
Static equilibrium is a special case in mechanics that is very important in everyday life. It occurs when the net force and the net torque on an object or system are both zero. This means that both the linear and angular accelerations are zero. Thus, the object is at rest, or its center of mass is moving at a constant velocity. However, this does not mean that no forces are acting on the object within the system. In fact, there are very few scenarios on Earth in which no forces are acting upon...