The phrase "ascertained from a" is correct and usable in written English.
It can be used when referring to information or knowledge that has been determined or discovered from a specific source.
Example: "The results of the study were ascertained from a comprehensive analysis of the data collected over five years."
Alternatives: "determined from a" or "derived from a".
The proposed statistical method can be modified to other population-based family data ascertained from a disease registry provided that the ascertainment process is well documented, and that external information concerning the sizes of birth cohorts and a suitable reference sample are available.
The properties of a fibril are easily ascertained from a simple tension test.
All but 1 of 112 first-episode psychosis cases ascertained from a geographical catchment area were traced at 10 12 years.
Rules of thumb for preliminary design can be ascertained from a qualitative examination of the governing equations of flow, which elucidate the relationships between 'core' variables – flow rates, air temperatures, heat inputs and building geometry.
At least, that's what the guests at the back of the room thought they heard him say, which provoked perplexed mutterings and wary smiles until it was ascertained, from a listener with keener hearing, that what Hertog had actually said is that the books are almost all long.
In brief, schizophrenic patients were ascertained from a variety of inpatient and outpatient centers in south Minnesota.
This architecture is based on requirements for DFR that we ascertained from an exhaustive review of the DFR literature.
Their identity can be ascertained from an inscription that surmounted the entrance of the niche where the Venus was found.
Influenza vaccination status (including vaccination date) was ascertained from an online immunization registry that is linked to clinical and non-clinical vaccination records from the region.
Cases between ages 0 2 with malnutrition but without other neurological or medical deficits were ascertained from an ambulatory Nutritional Rehabilitation Unit of a local hospital and matched with well-nourished cases of the same age and sex from the same socioeconomic background.
