The applicability of the NMR method was initially limited by its low sensitivity: it required incredibly concentrated solutions. But in 1966 the Swiss chemist Richard Ernst (Nobel Prize in Chemistry 1991) showed that this sensitivity could be increased dramatically if, instead of slowly varying the frequency, the sample was exposed to short and intense radio frequency pulses. He also contributed, during the 1970s, to the development of a way of determining what nuclei were adjacent to one another in a molecule, . two atoms bound to each other. By interpreting the signals in an NMR spectrum it was thus possible to gain an idea of the appearance of the molecule, its structure. The method was successful for relatively small molecules but, for larger ones, it was hard to differentiate between the resonances of the different atom nuclei. An NMR spectrum of this kind could look like a grass lawn in section – thousands of peaks where it was impossible to decide which peak belonged to which atom. The scientist who finally solved this problem was the Swiss chemist Kurt Wüthrich .
While Porter's Five Forces is an effective and time-tested model, it has been criticized for failing to explain strategic alliances. In the 1990s, Yale School of Management professors Adam Brandenbuger and Bare Nalebuff created the idea of a sixth force, "complementors," using the tools of game theory. In their model, complementors sell products and services that are best used in conjunction with a product or service from a competitor. Intel, which manufactures processors, and computer manufacturer Apple could be considered complementors in this model. More information can be found at Strategic CFO .