Introduction Knowledge, once acquired, degrades over time. Exams that contain questions related to previously acquired knowledge (‘retrieval practice questions’) may promote retrieval practice and spaced learning, and subsequently prevent knowledge loss. To investigate this hypothesis, we compare the score of retrieval practice questions to regular questions in exams of a two-year (bio)medical study program. Methods The two-year “Mechanisms of Health and Disease”-program for biomedical sciences and medical students in Nijmegen (the Netherlands) contains 14 spaced exams of 80 questions each. The percentages of correct-, false-, and non-answers were compared between regular questions and retrieval practice questions. Using Pearson correlations between question scores and exam scores (RiT-values), the impact of retrieval practice questions on the internal consistency of exams was determined. Mixed model analyses determined changes in outcomes across time. Results Analysis of 2006 regular questions and 1728 retrieval practice questions revealed a significantly higher percentage of correct and false answers, and a significantly lower percentage of non-answers, in retrieval practice questions versus regular questions (all P < 0.05). Scores did not change across time. RiT-values were slightly lower in retrieval practice questions, with a small inverse trend across time. Conclusion Our data indicate preservation of knowledge, possibly related to retrieval practice and/or spaced learning. Although the RiT-values of retrieval practice questions were slightly lower than those of regular questions, the discriminative capacity was well within acceptable range. These data highlight the potency of retrieval practice questions to prevent knowledge decrement, without altering exam quality.

The contribution of ciliates to rumen fermentation was estimated by determination of overall fibre degradation and cellulase activities (determined as carboxymethylcellulase activity) in faunated and defaunated ‘artificial rumen’ cultures. Experiments performed at loading rates of 22.5 and 35 g per liter per day of a grass‐grain substrate revealed that fibre degradation was significantly lower in the absence of ciliates only at the high loading rate. This effect of defaunation was smaller at dilution rates below 1.7 fermenter volume turnovers per day. Bacterial numbers were higher in all experiments after removal of ciliates. Fractionation studies demonstrated that ciliates accounted for 19–28% of the total cellulase activity in faunated cultures fed on filter paper cellulose.

In this setting in the Netherlands, PA students and MDs score about equal in the appraisal of common cases in medical practice. The slightly lower scores of PA students' clinical reasoning in the full scope of clinical care may have raise attention to medical teams working with PAs and PA training programmes.