The phrase "active in the second" is correct and usable in written English.
It can be used in contexts where you are discussing participation or involvement in a specific timeframe or event, particularly the second of something, such as a second round or second phase.
Example: "The team was particularly active in the second, making significant progress towards their goals."
Alternatives: "engaged in the second" or "participating in the second".
He was active in the second Great Awakening (1800 03), an evangelical religious movement in the southeastern U.S.
The president and the first lady, Michelle Obama, expressed their support for the group on Friday and asked their backers to stay active in the second term.
When the scientists looked at the data, however, they saw that a small fold of tissue on the surface of the right hemisphere, the anterior superior temporal gyrus (aSTG), became unusually active in the second before the insight.
About ~70% of ribosomes are active in the second elongation cycle, which further decrease to ~30% in the eighth elongation cycle.
The DXR enzyme is active in the second step of the MEP pathway for isoprenoid biosynthesis, which interconverts 1-deoxy-D-xylulose 5-phosphate and MEP.
The "in-situ" formed catalyst, active in the second reaction step, seems to be a lacunary poly-oxometalate in which cobalt, sequestered by the tungstate anion groups and accessible to the reagent, is the active component.
Compounds not detected as "active" in the first stage are tested for activity at the lowest tested concentration in the second stage.
This may be a systematic effect caused by participants being more active in the first 2 weeks because they knew that their activity was being measured by the accelerometer (otherwise known as the Hawthorne effect).
Jones was active in the first round, tagging Telesco with a couple of shots, but nothing telling.
Writers active in the first years of the 21st century, working in a variety of genres, included Niccolò Ammaniti, Andrea Camilleri, Antonio Tabuchi, and Carlo Lucarelli.
Generations of students were taught that the Spanish Inquisition was a permanent office of the Church in the Iberian peninsula, particularly active in the fifteenth and sixteenth centuries.
