Students’ ability to solve process-diagram problems in secondary biology education

Process diagrams are important tools in biology for explaining processes such as protein synthesis, compound cycles and the like. The aim of the present study was to measure the ability to solve process-diagram problems in biology and its relationship with prior knowledge, spatial ability and working memory. For this purpose, we developed a test that represents process diagrams and adjacent tasks used in secondary education biology. Results show that the ability to solve process-diagram problems is correlated to prior knowledge, spatial abilities and visuospatial working memory capacity. A difference in impact of spatial skills was demonstrated for the level of cognitive demand when solving process-diagram problems

Annoyance due to modulation noise and drop-outs in magnetic sound recording

In addition to a constant background noise, sound recordings on magnetic tape may also suffer from modulation noise and 'drop-outs'. The level of the modulation noise is proportional to that of the signa!. Modulation noise is more readily audiblein recordings of solo instruments than in orchestral music; listening tests have shown that for the flute the audibility threshold lies at a signal-to-noise ratio as high as 40 dB. The frequency with which drop-outs occur is a matter of tape quality. Listening tests have been carried out to determine the annoyance caused by drop-outs as a function oftheir duration, the degree of attenuation and the frequency of occurrence. The results of these experiments have been applied in the DAMA annoyance meter, which can measure these quantities for an audio tape and assign a quality rating to it