An experimental study of underwater radiated noise from a small vessel with damaged and fouled propellers.

Damage and fouling to a marine propeller can alter underwater noise levels through numerous mechanisms, but there are very few studies where clean propellers are compared to those with realistic levels of damage or fouling. This study presents acoustic data combined with underwater camera footage for a vessel fitted with three propellers: clean, damaged, and fouled. The results show that the fouled propeller is quieter than the clean one due to it reducing the levels of tip vortex cavitation.

Smaller species experience mild adversity under shading in an old-field plant community.

Plant competition experiments commonly suggest that larger species have an advantage, primarily in terms of light acquisition. However, within crowded natural vegetation, where competition evidently impacts fitness, most resident species are relatively small. It remains unclear, therefore, whether the size advantage observed in controlled experiments is normally realized in habitats where competition is most intense.

Prosodic features of familial language impairment: constraints on stress assignment.

This paper is part of a study of prosodic features of familial language impairment (FLI) in English. It reports the results of a set of experiments designed to investigate the factors that play a role in the assignment of stress to words which are longer than two syllables. It appears that stress assignment in FLI is constrained by a restriction limiting the maximal size of the stress domain to a bisyllabic unit, formally defined as the minimal prosodic word.