Alpha particle types: eventually named alpha, beta, and gamma by Rutherford, based on penetration of objects and deflection by a magnetic field. Alpha rays were defined by Rutherford as those having the lowest penetration of ordinary objects. Rutherford's work also included measurements of the ratio of an alpha particle's mass to its charge, which led him to the hypothesis that alpha particles were doubly charged helium ions (later shown to be bare helium nuclei). In 1907, Ernest Rutherford and Thomas Royds finally proved that alpha particles were indeed helium ions. To do this they allowed alpha particles to penetrate a very thin
Nitrogen-15 tracing be a bias by changing natural nitrogen transformations. In agricultural soil, however, application of N enriched tracers, such as ammonium and nitrate, resembles conventional fertilisation practise. A way to calculate nitrogen transformation rates in soil can be achieved by numerical approximation that takes different, simultaneous nitrogen transformations into account. A numerical tool to study the nitrogen cycle is the N model based on a Markov chain Monte Carlo simulation. Nitrogen-15 tracing Nitrogen-15 (N) tracing is a technique to study the nitrogen cycle using the heavier, stable nitrogen isotope N. Despite the different weights, N is involved in the same chemical