The immune system is a collection of billions of cells that travel through the bloodstream. They move in and out of tissues and organs, defending the body against foreign bodies (antigens), such as bacteria, viruses and cancerous cells.There are two types of lymphocytes :B cells-produce antibodies which are released into the fluid surrounding the bodyâs cells to destroy the invading viruses and bacteria. T cells (see picture opposite) - if the invader gets inside a cell, these (T cells) lock on to the infected cell, multiply and destroy it.here are two types of lymphocytes : B cells-produce antibodies which are released into the fluid surrounding the bodyâs cells to destroy the invading viruses and bacteria. T cells (see picture opposite) - if the invader gets inside a cell, these (T cells) lock on to the infected cell, multiply and destroy it.
Gillespieâs algorithm (Gillespie, 1977) is a way of im-. plementing consistently this probabilistic description of a biological system. The probabilistic. description by its very nature applies to single cells. The connection with molecular concentra-.
The algorithm may very well take less time on some inputs of size n, but it doesn't matter. If an algorithm takes T(n)=c*n2+k steps on only a single input of each size n and only n steps on the rest, we still say that it is a quadratic algorithm. A popular alternative to worst-case analysis is average-case analysis.here may even be some situations in which the constant is so huge in a linear algorithm that even an exponential algorithm with a small constant may be preferable in practice. This is a valid criticism of asymptotic analysis and big-O notation.