Energy Expenditure of Grade Four School Children in Western Australia

A composite team from the Public Health Service, the West Australian Institute of Technology, and the Graylands Teachers College conducted surveys on grade 7 children in 1974, and grade 4 children in 1975. The intention of the surveys was to find some relationship between the energy expenditure and the energy intake of each age group. As there is little information concerning the activity patterns of West Australian children the findings of these surveys would serve as a basis for more detailed reports into the physical fitness, activity and dietary balance of children in today\u27s changing society. The study reported below is of the 1975 survey conducted on grade 4 children

The Prehistory of Potyviruses: Their Initial Radiation Was during the Dawn of Agriculture

Background: Potyviruses are found world wide, are spread by probing aphids and cause considerable crop damage. Potyvirus is one of the two largest plant virus genera and contains about 15% of all named plant virus species. When and why did the potyviruses become so numerous? Here we answer the first question and discuss the other. Methods and Findings: We have inferred the phylogenies of the partial coat protein gene sequences of about 50 potyviruses, and studied in detail the phylogenies of some using various methods and evolutionary models. Their phylogenies have been calibrated using historical isolation and outbreak events: the plum pox virus epidemic which swept through Europe in the 20th century, incursions of potyviruses into Australia after agriculture was established by European colonists, the likely transport of cowpea aphid-borne mosaic virus in cowpea seed from Africa to the Americas with the 16th century slave trade and the similar transport of papaya ringspot virus from India to the Americas. Conclusions/Significance: Our studies indicate that the partial coat protein genes of potyviruses have an evolutionary rate of about 1.1561024 nucleotide substitutions/site/year, and the initial radiation of the potyviruses occurred only about 6,600 years ago, and hence coincided with the dawn of agriculture. We discuss the ways in which agriculture may have triggered the prehistoric emergence of potyviruses and fostered their speciation

Bridging conventional and molecular genetics of sorghum insect resistance

Sustainable production of sorghum, Sorghum bicolor (L.) Moench, depends on effective control of insect pests as they continue to compete with humans for the sorghum crop. Insect pests are a major constraint in sorghum production, and nearly 150 insect species are serious pests of this crop worldwide and cause more than 9% loss annually. Annual losses due to insect pests in sorghum have been estimated to be $1,089 million in the semiarid tropics (ICRISAT Annual report 1991. International Crop Research Institute for Semi-arid Tropics. Patancheru, Andhra Pradesh, India, 1992), but differing in magnitude on a regional basis. Key insect pests in the USA include the greenbug, Schizaphis graminum (Rondani); sorghum midge, Stenodiplosis sorghicola (Coquillett); and various caterpillars in the Southern areas. For example, damage by greenbug to sorghum is estimated to cost US producers$248 million annually. The major insect pests of sorghum on a global basis are the greenbug, sorghum midge, sorghum shoot fly (Atherigona soccata Rond.), stem borers (Chilo partellus Swin. and Busseola fusca Fuller), and armyworms (Mythimna separata Walk and Spodoptera frugiperda J.E. Smith). Recent advances in sorghum genetics, genomics, and breeding have led to development of some cutting-edge molecular technologies that are complementary to genetic improvement of this crop for insect pest management. Genome sequencing and genome mapping have accelerated the pace of gene discovery in sorghum..

Genetic Trends in the Estimated Feed Intake of Angus Cattle

Genetic trends are presented for the estimated feed intake of young Angus animals at pasture and in the feedlot, and of Angus cows at pasture for a self-replacing, 100d-finished production system. Increases in feed intake over time, both at pasture and in the feedlot, are estimated to have accompanied genetic gains in productivity traits in Angus cattle. The estimated increases are both in feed requirement and residual feed intake, with the latter being smaller in magnitude. The need for industry to record feed intake to facilitate selection for feed efficiency and, in the absence of this, for stocking rate to be managed in commercial herds to offset increases in feed intake, are factors briefly discussed in connection with industry realising benefits from genetic improvement

The Influence Feed Cost has on Changing Beef Cattle Greenhouse Gas Emissions

Genetic trends are presented for estimated greenhouse gas (GHG) emissions of young Angus animals at pasture and in the feedlot, and of Angus cows at pasture for a self-replacing, 100d-finished production system. GHG emissions are predicted to have increased over time, accompanying genetic gains in productivity traits and feed intake. The trends support the need for multiple trait selection that appropriately considers feed intake and the whole production chain. The results show the cost of feed used in the breeding objective impacts on the GHG emissions reductions that can be achieved with selection. Small reductions in GHG emissions can be achieved when feed is expensive, e.g. $130/t, and carbon is priced at$0/t. When feed is inexpensive GHG emissions increase and an $80/t carbon price is needed to make GHG emission changes negligible