The phrase "a first index" is correct and usable in written English.
It can be used when referring to the initial or primary index in a list, database, or any organized collection of information.
Example: "In the database, a first index is essential for efficient data retrieval and organization."
Alternatives: "an initial index" or "a primary index".
A first index for accounting the inflation in Puerto Rico was born by using the cost of living for working families in 1940.
A first index case is set at the initial time, and contaminated descendants are sampled in a negative binomial distribution.
Nine of the patients originally diagnosed correctly (cohort A) were treated uniformly according to the same prospective strategy used in a first index patient diagnosed in 1997 who had become a long-term survivor.
For patients with an initial correct diagnosis, a multimodal treatment strategy which was successful in a first index patient became the standard of treatment for all except two consecutive cases since 2002.
We divided our cohort into those with a first (index) (i) admission to hospital or (ii) high acuity ED visit for asthma between April 1, 2004 and March 31 , 2007
Thus, for the analysis, a first index describing impaired self-control and dependence symptoms, which roughly could be said to be problems of a more subjective nature, and a second index referring to extrinsic problems more concrete problems that affect others to a larger extent were retained.
A second index released on Tuesday showed a healthier market.
This primer also contained a second index in order to create more unique index combinations enabling more samples to be pooled per sequencing run.
A fifth index contains the complete abstract, together with the title and the list of Medical Subject Headings (MeSH) terms.
A second index in the new Living Planet report calculates humanity's "ecological footprint", ie the scale at which it is using up natural resources.
A third index is based on the residue matrices of the system transfer functions and the fourth is based on the (measured) complex modes of the system.
