Using the underground Sudbury neutrino detector, an international group of researchers has been able to determine that the observed number of electron-neutrinos is only a fraction of the total number emitted from the Sun - clear evidence that the particles change type en route to Earth.

BBC: SNO, SNO

Because these reactions are understood, it has been possible to estimate the number of electron-neutrinos that should emerge from our star.

BBC: SNO, SNO

It levelled out, as predicted, at around half the amount expected if no change was taking place, while the number of electron neutrinos was unchanged.

ECONOMIST: Neutrinos

One explanation for the solar-neutrino deficit (only a third of the predicted number have been detected) is that electron-neutrinos produced by nuclear-fusion reactions in the sun's core mutate into the other two types, which are harder to detect.

ECONOMIST: The news that neutrinos have mass is both good and bad

An electron microscope would be unreliable, particularly for someone infected a long time, because the number of cells harboring virus genes would be diluted over time and difficult to detect, said McGowan, the New York and New Jersey chairman of the American Academy of HIV Medicine.

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