Chest physiotherapy in primary pneumonia.

One hundred and seventy one patients with primary pneumonia entered a single blind, placebo controlled trial of physiotherapy. Treatment was allocated at random, physiotherapy consisting of postural drainage, external help with breathing, percussion, and vibration and the controls receiving advice on expectoration, deep breathing, and how to exercise to avoid thrombosis. Principles of pharmaceutical management were the same in the two groups. There was no objective evidence that daily physiotherapy helped during the acute phase of the disease. On the contrary, in younger patients, smokers, and patients with interstitial pneumonia physiotherapy appeared to prolong the duration of fever as well as the hospital stay. It is concluded that chest physiotherapy is at best useless in patients with primary infectious pneumonia.     

Materials for a study in animal competition

The incidence of the sewage fly, Psychoda alternata Say, breeding almost free from other insect competitors in a bacteria bed at Huddersfield is examined. Its general seasonal trend is marked by periods of peak output explained on the theory that there are two successions of generations running persistently and alternating with one another. Such behaviour has previously been demonstrated for another sewage fly, Spaniotoma minima , and has been shown to be instituted by irregular temperatures in autumn and spring. In Psychoda alternata a special type of intraspecific competition is set-up in the warmer months when the cycles are rapid, for the larvae of one succession must start life in a bed just depleted of food by the other. Therefore large and small outbursts of the fly tend to alternate. The discharges of solids from the bed have a detailed periodicity corresponding to the alternations in the successions of the fly.     

Population structure in an isolated Arctic fox, Vulpes lagopus, population: the impact of geographical barriers

The genetic composition of a population reflects several aspects of the organism and its environment. The Icelandic Arctic fox population exceeds 8000 individuals and is comprised of both coastal and inland foxes. Several factors may affect within-population movement and subsequent genetic population structure. A narrow isthmus and sheep-proof fences may prevent movement between the north-western and central part and glacial rivers may reduce movement between the eastern and central part of Iceland. Moreover, population density and habitat characteristics can influence movement behaviour further. Here, we investigate the genetic structure in the Icelandic Arctic fox population ( n  = 108) using 10 microsatellite loci. Despite large glacial rivers, we found low divergence between the central and eastern part, suggesting extensive movement between these areas. However, both model- and frequency-based analyses suggest that the north-western part is genetically differentiated from the rest of Iceland (F_ST = 0.04, D_S = 0.094), corresponding to 100–200 generations of complete isolation. This suggests that the fences cannot be the sole cause of divergence. Rather, the isthmus causes limited movement between the regions, implying that protection in the Hornstrandir Nature Reserve has a minimal impact on Arctic fox population size in the rest of Iceland.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 97 , 18–26.