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The modified Allen's test is also performed prior to heart bypass surgery. The radial artery is occasionally used as a conduit for bypass surgery, and its patency lasts longer in comparison to the saphenous veins. Prior to heart bypass surgery, the test is performed to assess the suitability of the radial artery to be used as a conduit.
The modified Allan variance (MVAR), [2] also known as mod σ y 2 (τ), is a variable bandwidth modified variant of Allan variance, a measurement of frequency stability in clocks, oscillators and amplifiers. Its main advantage relative to Allan variance is its ability to separate white phase noise from flicker phase noise.
During an interval of time τ, as measured by the reference clock, the clock under test advances by τy, where y is the average (relative) clock frequency over that interval. If we measure two consecutive intervals as shown, we can get a value of ( y − y ′ ) 2 —a smaller value indicates a more stable and precise clock.
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Watzke-Allen test is a test used in the diagnosis of a macular hole. It is a subjective test based on photoreceptor displacement. [1] Test can be used to differentiate full thickness macular hole from other similar conditions and also to assess retinal function after surgical closure of the hole. [2] [3]
The factor 1 / 2 used above looks arbitrary, but it guarantees superlinear convergence (asymptotically, the algorithm will perform two regular steps after any modified step, and has order of convergence 1.442). There are other ways to pick the rescaling which give even better superlinear convergence rates.
The test was developed at Harvard University in 1942. [3] Several modified versions of the original Harvard step test exist; examples include the Tecumseh step test and the Kasch step test. [5] Another modified version, the Sharkey step test, was developed in the 1970s for use by the United States Forest Service at the University of Montana in ...
The Ziehl-Neelsen stain is a two step staining process. In the first step, the tissue is stained with a basic fuchsin solution, which stains all cells pink. In the second step, the tissue is incubated in an acid alcohol solution, which decolorizes all cells except for acid-fast cells, which retain the color and appeared as red.