Search results
Results from the WOW.Com Content Network
A mathematical or physical process is time-reversible if the dynamics of the process remain well-defined when the sequence of time-states is reversed.. A deterministic process is time-reversible if the time-reversed process satisfies the same dynamic equations as the original process; in other words, the equations are invariant or symmetrical under a change in the sign of time.
Not all stationary processes are reversible, however, most commonly used DNA evolution models assume time reversibility, which is considered to be a reasonable assumption. Under the time reversibility assumption, let s x y = μ x y / π y {\displaystyle s_{xy}=\mu _{xy}/\pi _{y}\ } , then it is easy to see that:
The principle of microscopic reversibility in physics and chemistry is twofold: First, it states that the microscopic detailed dynamics of particles and fields is time-reversible because the microscopic equations of motion are symmetric with respect to inversion in time ( T-symmetry );
In maximum parsimony, Dollo parsimony refers to a model whereby a characteristic is gained only one time and can never be regained if it is lost. [8] For example, the evolution and repeated loss of teeth in vertebrates could be well-modeled under Dollo parsimony, whereby teeth made from hydroxyapatite evolved only once at the origin of vertebrates, and were then lost multiple times, in birds ...
Reversibility can refer to: Time reversibility , a property of some mathematical or physical processes and systems for which time-reversed dynamics are well defined Reversible diffusion , an example of a reversible stochastic process
Time reversibility – the ability of some processes to operate in either direction of time; Time reversal signal processing – a technique for focusing acoustic and electromagnetic waves by reversing in time a system's response signals; Time travel – theorised and speculative concepts about traveling into the past or the future
In biology, a substitution model, also called models of sequence evolution, are Markov models that describe changes over evolutionary time. These models describe evolutionary changes in macromolecules, such as DNA sequences or protein sequences, that can be represented as sequence of symbols (e.g., A, C, G, and T in the case of DNA or the 20 "standard" proteinogenic amino acids in the case of ...
T-symmetry or time reversal symmetry is the theoretical symmetry of physical laws under the transformation of time reversal, :. Since the second law of thermodynamics states that entropy increases as time flows toward the future, in general, the macroscopic universe does not show symmetry under time reversal. In other words, time is said to be ...