The streak of craziness; the thrill of the quest; the frequent difficulty of describing what their invention was, how it worked, what it was for; their vulnerability to ridicule, because what they had done or thought was new; and the need to protect that thought, as something interesting and precious in itself.
A frequent difficulty of image analysis is identification of false positive structures arising from background staining and tissue artefacts, thereby lowering the specificity and reliability of object recognition.
Much remains to be learned about molecular alterations and gene expression patterns in primary tumors versus their metastases, but these studies are complicated by the frequent difficulty of obtaining matched tissue samples, especially when metastases may be detected long after a primary tumor has been resected.
Over lands, the cloud detection on remote sensing images is not an easy task, because of the frequent difficulty to distinguish clouds from the underlying landscape, even at a high resolution.
In this group of patients, hearing loss is one of the most frequent difficulties.
The most frequent difficulties reported by the students were "lack of bibliography", "incomplete facilities", lack of transport, limited "access to computers, Internet … laboratories … and patients" and financial difficulties.
Rotator cuff tendinopathy and subacromial impingement syndrome present complex patomechanical situations, frequent difficulties in clinical diagnosis and lack of effectiveness in treatment.
Direct contact with the skin is necessary with traditional laser Doppler probes, and there are frequent difficulties in maintaining the same point of contact, making sequential measurements open to inaccuracy [ 27] furthermore, pressure may influence local perfusion itself [ 18].
The most frequent difficulties reported by students during the medical training were: "lack of books", and "financial needs".
The most frequent difficulties reported (these are not mutually exclusive) by students surveyed in 1998/99 were: "lack of reference materials/literature" (66% of students), and "financial problems" (58%).
