Flaveria Research Articles

Improving an Imperfect Metric System

Slowly, hesitantly, the public school system in the United States is moving toward the metric system. But in the English speaking world, accustomed to measuring distance by the length of a big man's foot or his reach, adopting the metric system for everyday use is likely to take a generation or more. In Florida, the state Department of Education has arranged for the conversion to begin in the current school year. But other state public instruction systems have been postponing the task because of the difficulties it poses for children whose concepts of measure are weak in conventional usage. Beyond the problems of conversion in the schools looms the conversion of measurement precepts and concepts for a whole population, a gigantic task.In this article, E. Lewis Frasier provides a detailed, comprehensive analysis of what the metric system is and how it might be improved. He is en aeronautical engineer and mathematician, presently employed by the Boeing Vertol Co. near Philadelphia as a senior engineering wr...

The Adventures of Big-Foot Wallace by John C. Duval

The Adventures of Big-Foot Wallace by John C. Duval

Tomato yellow top virus: Its distribution, characteristics and transmission by the aphid Macrosiphum euphorbiae (Thom.)

A study of the virus disease of tomato plants known as tomato yellow top is reported. The spread of the virus in eastern Australia from the Sydney metropolitan area in the period 1952–1960 is summarized and the current geographic distribution of the disease outlined. Symptoms of the disease on tomato plants, including the effect of plant vigour and age, are described. Symptoms on Physalis floridana are also described. Attempts to transmit the virus by mechanical means were unsuccessful, and no seed transmission was observed. The virus was transmitted by grafting and by the potato aphid, Macrosiphum euphorbiae, apterae of which appear to be the principal vector. Under experimental conditions the aphid required a minimum feeding period of 90 min to acquire the virus and 30 min to inoculate healthy seedlings. Optimal transmission of the virus was attained with an acquisition feed of 8 hr and an inoculation feed of 3 hr. Inoculated plants developed symptoms after 18–21 days. Infective aphids were able to cause transmission after moulting, and serially for 10 days without further feeding on infected plants. The virus was thus found to be of the "persistent" type. A weed, Solanum nigrum, is susceptible to tomato yellow top virus, and it is suggested that it is a source of infection for crops of tomatoes.

Big Foot Field, Frio County, Texas: ABSTRACT

The Big Foot oil field is in northeast Frio County, Texas, slightly downdip from the Balcones fault trend. Discovery was based on detailed subsurface stratigraphic studies supplemented by seismic and core-test data. The field produces from a stratigraphic trap type reservoir formed by the updip pinch-out of the Upper Cretaceous Olmos sands against a southeast-dipping unconformity. The producing zone occurs at about 3,500 feet. Production is near the marginal level; wells vary from 5 to 35 barrels of oil per day. End_of_Article - Last_Page 2624------------

Alfalfa “Yellow Top” and Leafhoppers1

The purpose of this paper is definitely to record in entomological literature some of the observations and experimental data, which proved beyond a doubt that the common potato leafhopper, Empoasca fabae (Harris), is responsible for the symptoms known as alfalfa “yellows” or “yellow top.” Healthy alfalfa plants in the field and in the greenhouse were caged and infested with leafhoppers collected from the affected alfalfa plants in the field. The initial symptoms on older plants were produced in five days of leafhopper feeding. The young seedlings showed wilting from 24 to 36 hours after the confinement of a single nymph on a young succulent shoot of alfalfa seedling. Prolonged feeding resulted in badly discolored, stunted plants, while the young seedlings were often killed outright. The root system of the infested plants was found to be weakened, which is considered an important contributing factor in the winter killing of alfalfa seedings.