The phrase "authors speculated that there" is grammatically correct and can be used in written English.
It is typically used in academic or research contexts when discussing hypotheses or theories proposed by authors regarding a particular subject or phenomenon.
Example: "In their study, the authors speculated that there might be a correlation between diet and mental health."
Alternatives: "the authors suggested that there" or "the authors hypothesized that there".
The authors speculated that there is a phase of increased medial temporal lobe activation early in the course of prodromal AD followed by a subsequent decrease as the disease progresses.
These authors speculated that there is greater disuse of leg muscles than of arm muscles with increasing age.
A case of well differentiated infiltrating adenocarcinoma in the focus of SRUS has also been reported and the authors speculated that there is a chance of adenocarcinoma originating from SRUS mucosa [ 26].
The authors speculated that there may be a potential protective role for HSP25/27 in kidneys with hypertensive nephropathy, similar to small molecular HSP32 (hemeoxygenase I; HO-I) which also has antioxidant properties [ 28].
And because the cross-cultural survey at the heart of this study suggested that -- at least among the men from Brazil, Cameroon, the Czech Republic, and Namibia that were studied -- the more important visual element was breast morphology, not size, the authors speculate that there's something about breast shape that tells a male that a female is especially fertile.
However, the authors speculate that there are at least two potential reasons why physiotherapists may have underestimated the summary utility score generated by the EQ-5D-3L instrument for patients with poorer cognitive abilities.
The authors speculate that could in part be down to the stigmatisation of same-sex sexual behaviour in black communities.
The authors speculated that this geographic variation might have developed due to real differences between races, or there might be differences in the identification of the disease, or differences in the rate of the use of diagnostic tests.
The authors speculated that different national responses may shape differences in approaches to the vaccine between Scottish and Polish women.
