"are carefully observed" is correct and usable in written English.
You can use it to describe an action that is monitored or studied closely. Example: The migratory patterns of birds are carefully observed by wildlife biologists.
But some works he painted on trips to North Africa and the Middle East are carefully observed documentations of religious and other customs.
In severely anemic patients, transfusions can safely be given provided the same precautions are carefully observed as in primary CAD [ 5].
If a subject refuses the treatment due to intolerably severe pain during the procedure, the procedure is stopped immediately and the degree of increase in pain and any abnormal reactions are carefully observed and recorded.
During this process physiological joint limitations are carefully observed; traction or high-velocity movements will not be applied, as may be the case in other forms of manual therapy [ 29].
Patient M-2 showed a partial decrease in their NY-ESO-1 humoral immune response levels after the resection of the relapsed tumour, and we are carefully observing the progression of this tumour.
The effects of the sleep deprivation were carefully observed.
Despite the publicity showered on her in the Hearst papers, the forms were carefully observed.
Hansen-Løve's depiction of Canvel and the French movie industry is carefully observed, full of fascinating detail, and infused with passion.
Each one is carefully observed and rendered on site, its flaws catalogued, its function (or sometimes, malfunction) acknowledged.
The purity standards of silver became rigorously controlled, and "hallmarking" was enforced; the marking of silver in England, especially, was carefully observed.
Monet's first success as an artist came when he was 15, with the sale of caricatures that were carefully observed and well drawn.
