How dangerous are falls in old people at home?

From a survey in six general practices information was obtained on 125 people aged 65 and over who fell in their own homes. Three fractured their femurs and 15 had other fractures; most of the rest suffered only trivial injuries. Twenty lay on the floor for more than one hour; none were known to have suffered hypothermia. One-quarter of these patients died within one year of the fall, five times as many as in an age- and sex-matched control group; while of those who lay on the floor for more than one hour, half died within six months of the fall. Factors associated with mortality from falls were impaired mobility, abnormal balance, and a disturbed pattern of gait. Falls at home in old age are often indicative of the presence of severe ill health.     

Host plant evaluation behaviour of Bemisia tabaci and its modification by external or internal uptake of imidacloprid

The behaviour of adult Bemisia tabaci Gennadius (Homoptera: Aleyrodidae) was observed on leaves of cotton, Gossypium hirsutum L., to study the process of host plant evaluation. Seven distinct behavioural elements were identified and recorded for a period of 20 min after initial contact with leaves. The behaviour of the whiteflies was observed on untreated leaves or on leaves treated with either foliar or systemically applied imidacloprid. Thus, contact with imidacloprid by whiteflies was either via the external cuticle or by ingestion, allowing determination of the effect of uptake route on host evaluation behaviour. Analysis of behavioural sequences and comparison of latencies, frequencies and durations of elements of behaviour between treatments revealed that host evaluation behaviour was similar on untreated and foliar treated leaves, but markedly different on those treated systemically. After their first probe, whiteflies on systemically treated leaves were much more active, spending significantly greater time walking and dabbing the labium tip onto the leaf surface. There was also a 50% reduction in the total time spent probing into systemically treated leaves, compared to the other treatments. This effect was the result of a shorter mean probe duration, and no effect of treatment was found on the frequency of probing. Pre-oviposition behaviour was significantly more common on the systemically treated leaves, although the number of eggs laid was similar on all treatments. These results also show that the host evaluation phase of adult female B. tabaci was dominated by probing. The behavioural sequence that leads to probing was affected significantly by imidacloprid when ingested, but not by direct contact with this compound on the leaf surface. The wider implications for the mechanisms of whitefly–host plant interactions are discussed.