Earlier blood tests and a DNA test were far less predictive, and celiac disease has been difficult to identify, especially because its symptoms vary widely.
But he also concedes that Papua is large and that it has been difficult to identify who is an original inhabitant of these villages.
Although in some instances there is clear evidence that perceptual learning is associated with changes in cognitive processing, the mechanisms behind perceptual learning have been difficult to identify.
The numbers are necessarily incomplete because judicial campaigns in many states are lightly regulated, and it's often been difficult to identify the real sources of contributions — even before the Supreme Court decided Citizens United, in 2010.
Traditionally, it has never been difficult to identify an optimist: the rule of thumb was that if you saw your whisky glass as half full, you were an optimist.
Since the error only occurred in certain cases, it had not been previously noticed and would have been difficult to identify without such a comparative study.
However, given the rich and complex composition of suppressive factors, the microbes involved in disease suppression have been difficult to identify.
Despite their potential clinical importance in chemotherapy, TLS inhibitors have been difficult to identify since a direct assay designed to quantify genomic TLS events is still unavailable.
Although the surgical approach to the ilioinguinal nerve is now well established, it has been difficult to identify the genitofemoral reliably enough to permit resection of this nerve.
Moreover, as Datashare was still reviewing several options for further development of their innovation, Noorman et al. (2017) remark that it may have also been difficult to identify relevant stakeholders in the first place.
The aetiology of OA is largely unknown, but since it may involve multiple factors, including mechanical, biochemical and genetic factors, it has been difficult to identify unique targets for therapy.
