The fuzzy frontier

THE STORY OF HOW FEATHERS EVOLVED IS FAR FROM OVER. IN 1868, THOMAS HUXLEY declared that dinosaurs gave rise to birds. He based his claim on Compsognathus, a 150-million-year-old dinosaur fossil from Solnhofen, Germany, whose delicate hind legs were remarkably similar to those of table fowl. The discovery seven years earlier of Archaeopteryx, a fossil bird with a long bony tail, toothed jaws and clawed fingers, had convinced many people that birds were somehow related to reptiles. But Compsognathus was the fossil that placed dinosaurs firmly in the middle of this complex evolutionary equation. Wings, claimed Huxley, must have grown out of rudimentary forelimbs. And feathers? Whether Compsognathus had them, Huxley could only guess. Nevertheless, his theory clearly required that scales had somehow transformed into feathers. The question was not just how, but why?

Preliminary findings of a systematic review and expert opinion workshop on Biosecurity on cattle farms in the UK

In this paper risk factors for the introduction of IBR, BVD, Salmonella and Johne's disease to cattle farms are reported. Two sources of information were used: literature was searched systematically and an expert opinion workshop was held. The findings from both indicate that direct contact between cattle is an important risk factor. Indirect and occasional contact is considered of less importance. Therefore, in the development of biosecurity programmes for cattle farms emphasis should be put on preventing direct contact with cattle from outside the herd.

The fraction of ischaemic heart disease and stroke attributable to smoking in the WHO Pacific and South-East Asian regions

Background: Tobacco will soon be the biggest cause of death worldwide, with the greatest burden being borne by low and middle-income countries where 8/10 smokers now live. Objective: This study aimed to quantify the direct burden of smoking for cardiovascular diseases (CVD) by calculating the population attributable fractions (PAF) for fatal ischaemic heart disease (IHD) and stroke (haemorrhagic and ischaemic) for all 38 countries in the World Health Organization Western Pacific and South East Asian regions. Design and subjects: Sex-specific prevalence of smoking was obtained from existing data. Estimates of the hazard ratio (HR) for IHD and stroke with smoking as an independent risk factor were obtained from the,600 000 adult subjects in the Asia Pacific Cohort Studies Collaboration (APCSC). HR estimates and prevalence were then used to calculate sex-specific PAF for IHD and stroke by country. Results: The prevalence of smoking in the 33 countries, for which relevant data could be obtained, ranged from 28-82% in males and from 1-65% in females. The fraction of IHD attributable to smoking ranged from 13-33% in males and from < 1-28% in females. The percentage of haemorrhagic stroke attributable to smoking ranged from 4-12% in males and from < 1-9% in females. Corresponding figures for ischaemic stroke were 11-27% in males and < 1-22% in females. Conclusions: Up to 30% of some cardiovascular fatalities can be attributed to smoking. This is likely an underestimate of the current burden of smoking on CVD, given that the smoking epidemic has developed further since many of the studies were conducted.