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Equation 45 · Part 1 · The Valley of Stability Is a Fitness Landscape

Symbol N

NN
NN

What this part means

the closed in both.

Its job in the formula

N is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

Where the article explains it

The signature is sharpest in the neutron (or proton) separation energy — the cost of removing one more nucleon from an otherwise identical isotope — which drops abruptly immediately after a magic number is crossed, the nuclear analogue of a fitness cliff rather than a gentle slope; a doubly magic nucleus, closed in both N and Z simultaneously, sits at the intersection of two such cliffs and is correspondingly the most sharply peaked point in its neighborhood on the whole chart.

The passage around this formula

…nucleon from an otherwise identical isotope — which drops abruptly immediately after a magic number is crossed, the nuclear analogue of a fitness cliff rather than a gentle slope; a doubly magic nucleus, closed in both N and Z simultaneously, sits at the intersection of two such cliffs and is correspondingly the most sharply peaked point in its neighborhood on the whole chart.

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Learn the underlying idea

A variable is a named place for a value. Its letter is a local label: x can mean position in one formula and a data point in another.

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Sources cited in the surrounding passage

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