A more area-selective method is electron energy loss spectroscopy, which measures the energy loss of an electron beam within a transmission electron microscope when it interacts with a portion of a sample.
According to an interview from the article, one facility had been storing samples of enriched (weapons grade) uranium in a broom closet before the improvement project; another had been keeping track of its stock of nuclear warheads using index cards kept in a shoe box.
Although the earliest methods commonly used gas chromatography, the high temperature required to vaporize the psilocybin sample prior to analysis causes it to spontaneously lose its phosphoryl group and become psilocin—making it difficult to chemically discriminate between the two drugs.
Although this early example of an ensemble showed skill, in 1974 Cecil Leith showed that they produced adequate forecasts only when the ensemble probability distribution was a representative sample of the probability distribution in the atmosphere.
Analyses published in 2009 concluded that the sample originated at Oak Ridge, and was one of several sent to Hanford for optimisation tests of the T-Plant until Hanford could produce its own plutonium.
Gerta Keller of Princeton University argues that recent core samples from Chicxulub prove the impact occurred about 300,000 years before the mass extinction, and thus could not have been the causal factor.
Ghosts I–IV features a wide assortment of musical instruments, including piano, guitar, bass, synthesizer, marimba, tambourine, banjo, dulcimer, and xylophone, many of which were sampled and distorted electronically.
He has called for the introduction of blood testing, promised to surrender a frozen sample for retrospective testing and repeatedly criticised FINA for drug-testing procedures that he regards as inadequate.
However, at present only a small part of the total diversity of viruses has been studied, with analyses of samples from humans finding that about 20% of the virus sequences recovered have not been seen before, and samples from the environment, such as from seawater and ocean sediments, finding that the large majority of sequences are completely novel.
If tuberculous meningitis is suspected, the sample is processed for Ziehl-Neelsen stain, which has a low sensitivity, and tuberculosis culture, which takes a long time to process; PCR is being used increasingly.