Concise writing
Scientific writing should be concise. This means avoiding redundant words and phrases.
In example (1a), some words and phrases (in bold) are redundant and might distract the reader from the main message:
Wordy
(1a) At this point in time users are in the process of learning the new techniques.
More concise
(1b) Users are currently learning the new techniques.
In example (2a), significant is an unnecessary repetition of important, and the degree adverbs fairly and very contribute little to the sentence in this case. Degree adverbs are often unnecessary in scientific writing if precise verbs, adjectives, and adverbs are used:
Wordy
(2a) These changes are not only fairly important but they are also very significant.
More concise
(2b) These important changes are statistically significant.
In example (3a), note the redundancy of the passive structure have been observed:
Wordy
(3a) High temperatures have been observed to occur at the site.
More concise
(3b) High temperatures occur at the site.
(3c) The site is known for its high temperatures.