"During chronic experiments, when the animal, having recovered from its operation, is under lengthy observation, the dog is irreplaceable," he noted in 1893.
The 30-day option was introduced in 1997, amending rules that had been in place since 1912, when lengthy observation of animals in isolation was the only reliable way to make sure they did not have rabies.
This cohort offered several advantages for the study of HAdVs; the lengthy observation period and frequent sampling of both the anal and genital areas permitted sensitive detection of short episodes of subclinical infection, and a determination of whether adenovirus infection of the genital tract was present.
Although this study was well-designed and covered a lengthy observation period, it was restricted to a single setting in a single country.
While it is conceivable that the steady activity of even a small number of effector T-cells could significantly degrade the number of surviving RGC cells over the lengthy observation period, an alternative explanation is also possible.
When the exposure of interest is adherence to chronic medication, measured during a lengthy observation period that begins with an acute and traumatic event, the selection of controls using time-independent sampling may underestimate any beneficial adherence effect.
Ms. Kor recalls sitting naked, arms tied to a bench, for six to eight hours while every part of her body was examined, measured and compared with charts in lengthy, demeaning observations several times a week.
Sources of data include semi-structured interviews conducted with 130 residents, transect walks with two expert herders, a focus group discussion with six expert herders, validation interviews with two wazee (highly respected elders, plural), two participatory mapping exercises and with additional contributions from lengthy participant observation.
The FBI's evidence suggests a lengthy period of observation.
