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Typical oils used have an index of refraction around 1.515. [2] An oil immersion objective is an objective lens specially designed to be used in this way. The index of the oil is typically chosen to match the index of the microscope lens glass, and of the cover slip. For more details, see the main article, oil immersion.
Standard refractive index measurements are taken at the "yellow doublet" sodium D line, with a wavelength (λ) of 589 nanometers. There are also weaker dependencies on temperature , pressure / stress , etc., as well on precise material compositions (presence of dopants , etc.); for many materials and typical conditions, however, these ...
A database index is a data structure that improves the speed of data retrieval operations on a database table at the cost of additional writes and storage space to maintain the index data structure. Indexes are used to quickly locate data without having to search every row in a database table every time said table is accessed.
In predictive analytics, a table of confusion (sometimes also called a confusion matrix) is a table with two rows and two columns that reports the number of true positives, false negatives, false positives, and true negatives. This allows more detailed analysis than simply observing the proportion of correct classifications (accuracy).
Matching is a statistical technique that evaluates the effect of a treatment by comparing the treated and the non-treated units in an observational study or quasi-experiment (i.e. when the treatment is not randomly assigned).
For referential integrity to hold in a relational database, any column in a base table that is declared a foreign key can only contain either null values or values from a parent table's primary key or a candidate key. [2] In other words, when a foreign key value is used it must reference a valid, existing primary key in the parent table.
People who bought the snacks with the “non-GMO ingredients” graphic in the U.S. between Feb. 2, 2017, through Dec. 6, 2024, can “submit a valid timely” claim form by July 28, 2025.
Suppose they are assessed on the five criteria (see Table 1) like this: Maartje's education is excellent, she has > 5 years of experience, and her references, social skills and enthusiasm are all poor. Michelle's education is poor, she has 2–5 years of experience, and her references, social skills and enthusiasm are all good.