The phrase "are selected at a" is correct and usable in written English.
It can be used in contexts where you are describing a process of selection that occurs at a specific point or under certain conditions.
Example: "The candidates are selected at a later stage in the recruitment process."
Alternatives: "are chosen at a" or "are picked at a".
In most cases, operation points for multimedia services are selected at a higher bit rate and higher BLER compared to those of non-real-time services.
The most likely non-conflicting gene models are selected at a given locus, based on Pfam evidence and protein length agreement with the BLAST hits.
They also support the notion that the positions are selected at a later stage through dynamic interactions between cells [1], [18].
In earlier generations the parent lines are selected at a single plant basis but not for combining abilities or heterosis.
On the female parent, flowers are selected at a developmental stage just prior to anther bursting and pollen release.
Co-expressed genes are selected at a certain PCC cutoff threshold, and a co-expression network was constructed and visualized by Cytoscape software (http://www.cytoscape.org/).org/
From time to time, the BMBF issues calls for applications from people with a specific profile or set of skills--those applicants are selected at an assessment center.
In China, potential curling stars are selected at an early age and train eight hours every day with the hope of making it big or as big as curling can get.
Single colonies were selected at each step to be grown at the consecutive ciprofloxacin concentration and simultaneously a sample was frozen and named according to the ciprofloxacin concentration of selection (e.g., strain 50-0.007 waselecteded at a ciprofloxacin concentration of 0.007 µg/mL).
In the first stage of female selection, 150 of the 300 female candidates were selected at a young age based on a multi-trait index of GEBV.
No changes in selection strategy were implemented on the male side: 50 males were selected at a young age on a multi-trait index of genomic EBV (GEBV).
