When the signal frequency reaches half the sampling frequency, there are only two samples per cycle, which is the absolute minimum needed to record a waveform. A higher frequency would cause the digitization system to alias.

He drifted past four Palace players and took on two more before crossing to the far post, where Fellaini touched on for Mata to score. It was a momentum-shifting moment.

As just one examples, on the other side of China a parallel occurrence is recorded in the gazetteer published by Ziyang county in Shaanxi Province (Xian: Sangin Chubanshe, pp. 521-26): During the nationwide wave of “power seizures” in early 1967, two antagonistic factions had emerged in the county capital—“Eryipai,” to which the preponderance of teachers and secondary-school students belonged, and “Erliupai,” based more heavily on cadres, peasants and workers. In 1968 the factional fighting in the county escalated, and in April military and police ammunition was seized by the two factions. Members of the weaker Eryipai soon thereafter fled the county and joined their allies in neighboring counties. Amid rear-guard armed fighting, many of the adherents of Eryipai who remained behind were rounded up, along with their families and members of the “bad classes.” Over 400 were tortured and then murdered, including 211 labeled as “bad- class.” By the end of 1968 a PLA unit entered the county to end the bloodshed.

[O]bſerving … abundance of Matter floating in the Urine like Bran, with a great Number of Recrements like Cuttings of Hair, ſome above an Inch long, which Subſtances were found in all the Water that I made in above Twelve Months; for which I could get no Remedy: I was adviſed to drink Water, which in about half a Year did intirely free me from thoſe Symptoms, …