Search

Seedling emergence, survival and species composition were recorded on vegetation subjected to seven practicably feasible soil and defoliation treatments. Soil disturbance, with defoliation removal, produced the greatest number of emergents; these also had the best survivorship compared to other treatments. Recruitment of desirable species in humid South African rangelands seems to require not only sufficient seed supply, but also improved conditions for their emergence and survival. The latter seems to be best achieved by eliminating competition, inter alia by tilling the soil. Where no soil or defoliation treatment was applied, no surviving seedlings were produced.

An analogue computer that simulates various types of civil engineering structures under earthquake conditions ia described. In § 2 various types of idealized structure are examined, and in § 3 various idealized electrical systems that are structural analogues are proposed. One of these is selected as the basis of a practical system. This practical device is then described and results obtained from it compared with calculations in § 4. It is concluded that the present device is in many respects to be preferred over existing equipment.

Spontaneous intracranial hypotension (SIH) causes postural headache and neurologic symptoms owing to traction and brain compression. A 66-year-old man with chronic headache and progressive personality and behavioral changes typical of frontotemporal dementia was examined. He had MRI findings of SIH with low CSF pressure. His headache, dementia, and imaging abnormalities abated after treatment with prednisone. SIH can cause reversible frontotemporal dementia, and should be considered when dementia and behavioral changes are accompanied by headache.