Rather than fully removing the key from the map, we set the register value to null. The metadata is kept around so we can disambiguate deletions from states that simply don’t have a key yet. These are called tombstones — the ghosts of CRDTs past.
In 2006, 454 collaborated with Swedish paleogeneticist Svante Pääbo to sequence the first million base pairs of the Neanderthal genome; the project would be completed four years later, albeit with some help from Illumina sequencing. Illumina and other subsequent NGS technologies rendered pyrosequencing non-competitive, and in 2013, 454 was shut down by Roche, which had acquired it six years earlier. The technology is still used today for some applications, but most importantly, it was the first commercially viable alternative to Sanger sequencing, and the first sequencing method that could be fully automated because it didn’t rely on gels or other tedious steps.
，这一点在体育直播中也有详细论述
Раскрыты траты россиян на путешествия в Международный женский день20:37
Одна из причин развития близорукости — слишком яркий или тусклый свет монитора, предупредил Азнаурян.