Isotopes of helium a thousand times lower than helium-4 (2.17 K). This difference is explained by quantum statistics, since helium-3 atoms are fermions, while helium-4 atoms are bosons, which condense to a superfluid more easily. The most common isotope, , is produced on Earth by alpha decay of heavier radioactive elements; the alpha particles that emerge are fully ionized nuclei. is an unusually stable nucleus because its nucleons are arranged into complete shells. It was also formed in enormous quantities during Big Bang nucleosynthesis. Terrestrial helium consists almost exclusively (99.99986%) of this isotope. Its boiling point of 4.2 K is the lowest of
The Elements of Style at the University of Edinburgh, and co-author of "The Cambridge Grammar of the English Language" (2002), said that: Pullum has argued, for example, that the authors misunderstood what constitutes the passive voice, and he criticized their proscription of established and unproblematic English usages, such as the split infinitive and the use of "which" in a restrictive relative clause. On "Language Log", a blog about language written by linguists, he further criticized "The Elements of Style" for promoting linguistic prescriptivism and hypercorrection among Anglophones, and called it "the book that ate America's brain". "The Boston Globe" review described "The Elements of