Pollen calendar Pollen calendar A pollen calendar is used to show the peak pollen times for different types of plant pollen, which causes allergic reactions in certain people. A pollen calendar can be a very useful tool in forensic science, because it can be used to place the month, or week, or date of death. The use of pollen for criminal investigation purposes is called "forensic palynology". However, the use of a pollen calendar to set the date of death should be used with extreme caution, and only by a carefully trained expert witness. The CSI effect has put pressure on some
Beta decay atoms obtain a more stable ratio of protons to neutrons. The probability of a nuclide decaying due to beta and other forms of decay is determined by its nuclear binding energy. The binding energies of all existing nuclides form what is called the nuclear band or valley of stability. For either electron or positron emission to be energetically possible, the energy release (see below) or Q value must be positive. Beta decay is a consequence of the weak force, which is characterized by relatively lengthy decay times. Nucleons are composed of up quarks and down quarks, and the weak force