Activation

The term activation, in general, refers to the state or process of making something active and/or effective. It is frequently associated in biochemistry with a molecule becoming more reactive, active, or excited for the next reaction. In the translation step of protein biosynthesis, for example, activation is the first step in which the correct amino acid is covalently bonded to the correct RNA. This is a necessary step in the translation process. Activation (or bio activation) can also refer to the process or state of becoming more effective at performing a specific function. For example, activating an enzyme causes it to perform its specific biological function. Another example is the conversion of an inactive prodrug into an active metabolite. In radiobiology, activation (also known as radio activation) occurs when a particle interacts with an atomic nucleus, causing the nucleus to become unstable and radio activation. The neutron released when (D – T) combine to form (4He – n) can activate the reactor structure in fusion research, where deuterium-tritium is a common fuel mixture. In this case, the 4He is inert, the neutron adheres to another nucleus, and the neutron–nucleus reaction produces an activation product.

Activation

In psychology, activation, also known as arousal, is the stimulation of the cerebral cortex into a state of general wakefulness or attention. Activation occurs in various parts of the brain, but most notably in the reticular formation, a nerve network in the midbrain that monitors ingoing and outgoing sensory and motor impulses. However, activation differs from direct cortical stimulation by specific sense receptors, such as being awakened by noise. It is, rather, a complex of both internal and external to the body impulses. The degree of arousal is measured using electroencephalography (EEG).

Mathematical expression Activation energy 

Activation energy is the minimum amount of energy required to activate atoms or molecules to the point where they can undergo chemical transformation or physical transport. The activation energy is a difference in energy content between atoms or molecules in an activated or transition-state configuration and the corresponding atoms or molecules in their initial configuration in transition-state theories.the magnitude of the activation energy:

and the mathematical expression is

                             k = A exp(−Ea/RT) 

Experimental rate constants or diffusion coefficients measured at different temperatures are used to calculate activation energies.

Comparison of activation functions

Activation functions have a variety of mathematical properties in addition to their empirical performance:

Nonlinear

A two-layer neural network can be proven to be a universal function approximator when the activation function is nonlinear. The Universal Approximation Theorem states this. This property is not met by the identity activation function. The entire network is equivalent to a single-layer model when multiple layers use the identity activation function.

Range

Gradient-based training methods are more stable when the range of the activation function is finite, because pattern presentations significantly affect only a subset of weights. Training is generally more efficient when the range is infinite because pattern presentations have a significant impact on the majority of the weights. Smaller learning rates are usually required in the latter case.

Continuously differentiable

This property is desirable for enabling gradient-based optimization methods (ReLU is not continuously differentiable and has some issues with the gradient-based optimization, but it is still possible). Because the binary step activation function is not differentiable at 0 and differentiates to 0 for all other values, gradient-based methods cannot progress with it.

Activation Meaning

The implementation of a school policy to combat bullying both kicks off the programme and inspires people to participate in it. Activation derives from the same Latin root as the adjective active, actus, which means “a doing, a driving, or an impulse.”

SI Unit of Activation Energy

Represents the Activation energy. It is usually expressed in joules (J), kilojoules per mole (kJ/mol), or kilocalories per mole (kcal/mol).

Factors Affecting Activation Energy

The activation energy is determined by two factors.

Nature of Reactants

Because there is an attraction between reacting species in the case of an ionic reactant, the value of (Ea) will be low. In the case of a covalent reactant, the value of Ea will be high due to the energy required to break the older bonds.

Effect of Catalyst

A positive catalyst creates an alternate path in which the value of Ea is low, whereas a negative catalyst creates an alternate path in which the value of Ea is high.

Conclusion

The term activation, in general, refers to the state or process of making something active and/or effective. In the translation step of protein biosynthesis, for example, activation is the first step in which the correct amino acid is covalently bonded to the correct RNA. In this case, the 4He is inert, the neutron adheres to another nucleus, and the neutron nucleus reaction produces an activation product. In psychology, activation, also known as arousal, is the stimulation of the cerebral cortex into a state of general wakefulness or attention. It is, rather, a complex of both internal and external to the body impulses. The activation energy is a difference in energy content between atoms or molecules in an activated or transition-state configuration and the corresponding atoms or molecules in their initial configuration in transition-state theories. Activation functions have a variety of mathematical properties in addition to their empirical performance: A two-layer neural network can be proven to be a universal function approximator when the activation function is nonlinear. The entire network is equivalent to a single-layer model when multiple layers use the identity activation function.