Natural Selection Towards Wild-Type in Composite Cross Populations of Winter Wheat.

Most of our crops are grown in monoculture with single genotypes grown over wide acreage. An alternative approach, where segregating populations are used as crops, is an exciting possibility, but outcomes of natural selection upon this type of crop are not well understood. We tracked allelic frequency changes in evolving composite cross populations of wheat grown over 10 generations under organic and conventional farming.

The increased use of diversity in cereal cropping requires more descriptive precision.

Background: Until 100 years ago, cereals were grown only as populations with varying amounts of genetic diversity both within and among different crops. However, since the nineteenth century, methods for isolating and reproducing monocultural varieties have become universal, particularly among larger producers, leading to widespread within-field genetic monotony. A range of approaches is now being used to increase genetic diversity within and among crops including bringing back into cultivation a range of populations using a variety of different names, such as old varieties, landraces, ancient grains, heritage varieties, heirloom varieties, and mixtures.

Resilience as a universal criterion of health.

To promote and maintain health in agricultural and food systems, appropriate criteria are needed for the description and assessment of the health of soils, plants, animals, humans and ecosystems. Here we identify the concept of resilience as a universally applicable and fundamentally important criterion of health in all relevant areas of agriculture. We discuss definitions of resilience for soils, plants, animals, humans and ecosystems, and explore ways in which resilience can be applied as a criterion of health in different agricultural contexts.

Safety of Typhim Vi vaccine in a postmarketing observational study.

Background: Typhoid fever is endemic in many parts of the world. In the United States, nearly three quarters of all cases are contracted by persons who traveled to regions with endemic disease. Typhim Vi, a vaccine containing the purified cell surface Vi polysaccharide of the Salmonella enterica serovar Typhi, was developed to provide protection against typhoid fever.

Historical Lassa fever reports and 30-year clinical update.

Five cases of Lassa fever have been imported from West Africa to the United States since 1969. We report symptoms of the patient with the second imported case and the symptoms and long-term follow-up on the patient with the third case. Vertigo in this patient has persisted for 30 years.