Disease vector
A disease vector is an insect, animal or other organism which spreads disease indirectly. It is not the the thing which causes the disease, but is a "carrier". Mosquitoes carry a parasite which causes malaria. Dogs can carry a germ which cause rabies.
In genetics, a vector is an agent, such as a virus or a small piece of DNA called a plasmid, that carries a modified or foreign gene. When used in gene therapy, a vector delivers the desired gene to a target cell.
In mathematics, a vector is a quantity with magnitude and direction. For example, an airplane has speed and a compass heading (e.g., 600 MPH, headed North).
In physics, velocity is a vector quantity while speed by itself is a scalar quantity.
Vectors in math and physics are typically graphed as arrows pointing in the direction of a quantity such as velocity. The length of the arrow shows its magnitude. This makes it easy to add vector quantities (you line up the tail of one arrow with the point of the other).
In computer science, vector has many meanings, in addition to the mathematical one given above:
- A data structure which allows random access to its contents but which can also be extended. Typical of this is the C++ programming language Standard Template Library use.
- A vector processor carries out operations on many elements of an array at the same time
- Vector graphics are a form of graphics defined by line and shape primitives, compared with bitmap graphics where they are defined by image data.