Ernest Lawrence a scrap of a paper napkin. While sitting in the library one evening in 1929, Lawrence glanced over a journal article by Rolf Widerøe, and was intrigued by one of the diagrams. This depicted a device that produced high-energy particles by means of a succession of small "pushes". The device depicted was laid out in a straight line using increasingly longer electrodes. At the time, physicists were beginning to explore the atomic nucleus. In 1919, the New Zealand physicist Ernest Rutherford had fired alpha particles into nitrogen and had succeeded in knocking protons out of some of the nuclei. But
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