Angular Momentum Distribution Function of the Laughlin Droplet

We have evaluated the angular-momentum distribution functions for finite numbers of electrons in Laughlin states. For very small numbers of electrons the angular-momentum state occupation numbers have been evaluated exactly while for larger numbers of electrons they have been obtained from Monte-Carlo estimates of the one-particle density matrix. An exact relationship, valid for any number of electrons, has been derived for the ratio of the occupation numbers of the two outermost orbitals of the Laughlin droplet and is used to test the accuracy of the MC calculations. We compare the occupation numbers near the outer edges of the droplets with predictions based on the chiral Luttinger liquid picture of Laughlin state edges and discuss the surprisingly large oscillations in occupation numbers which occur for angular momenta far from the edge.Comment: 11 pages of RevTeX, 2 figures available on request. IUCM93-00

The large area crop inventory experiment: A major demonstration of space remote sensing

Strategies are presented in agricultural technology to increase the resistance of crops to a wider range of meteorological conditions in order to reduce year-to-year variations in crop production. Uncertainties in agricultral production, together with the consumer demands of an increasing world population, have greatly intensified the need for early and accurate annual global crop production forecasts. These forecasts must predict fluctuation with an accuracy, timeliness and known reliability sufficient to permit necessary social and economic adjustments, with as much advance warning as possible

The Beginning of a National and State Forestry Program in Iowa

Probably one of the most important problems which Iowa is facing today relates to adjustments in land use. For many years, conservationists have anticipated the time when a real start would be made in the public acquisition of forest lands which are not best adapted to agricultural use. Apparently this time arrived when the National Forest Reservations commission approved, on January 21, 1935, purchase units with a gross area of 829,000 acres for national forests in Iowa

The growth, returns and uses of planted cottonwood in Iowa

Cottonwood is one of the fastest wood producers grown in Iowa. A fair yield from 35 year old cottonwood plantations is 30,000 board feet of lumber and 50 cords of fire-wood per acre. The average production found in single rows one-half mile long was 71,000 board feet, and 274 cords of fire-wood. When growing fence posts cottonwood will produce over 600 first class posts in 6 years, or over 1,400 in 12 years, per acre. Cottonwood posts untreated last about three years and should not be used until treated with creosote or some other preservative. Creosoting cottonwood posts costs about 15 to 20 cents each. After treatment they will last 20 to 25 years. On overflowed land unsuited for agricultural crops cottonwood plantations 35 years old will produce in lumber and cord-wood an average annual return of $10.09 in addition to six percent compound interest on the money invested. On waste land cottonwood fence posts produce an annual profit of$5.67 to $7.39 an acre in addition to six percent compound interest on the investment. Cottonwood fence posts for local farm use can be grown profitably on land valued as high as$100 an acre. Cottonwood lumber is very serviceable for rough construction work in barns, sheds, and similar uses, especially in places protected from the weather and contact with the ground. This lumber on the farm takes the place of other lumber which costs $30 to$50 per M. When planted, the trees should be spaced about 6 by 6 or 7 by 7 feet apart. The number of trees in the stand should be reduced in about three thinnings from approximately 900 per acre at the start to between 125 and 175 at the end of the 35-year rotation

The Prairie Sprouts Its Foresters

Iowa State College was one of the first schools to give some organized training in forestry subjects. As far back as 1874 the college included a department of Horticulture and Forestry. Although sketchy from the 1948 viewpoint, the forestry instructional program, at that early date, embraced seedbeds, hedging, economical aboriculture, (practical forestry) and shelterbelts, which made up a part of the four year course for the department. This early instructional work at the college was an outgrowth of unusual activity of the state in tree planting, shelterbelts and fruit trees. At that early date Iowa was probably more active in this general field than any of the other states. This came about through federal and state legislation and state organizations, especially the Iowa Horticultural Society. A number of both practical and scientific men seemed to foresee the needs for protective tree planting in a prairie state like Iowa

The Forestry Program

The need of drastic steps in our forestry program is not questioned by the majority of people who take time to consider the condition of our forest resources. Definite action on the part of the federal government and the state is conceded to be a necessity by those in closest touch with our economic pulse. The best means of accomplishing a nation-wide forestry program is a debatable question but the same end is desirable to all foresters and other citizens looking to the welfare of the country. It does not require the aid of the economist or forester to point out the shallowness of our present forest policy. We are somewhat in the position of the colored gentleman who turned down a good salaried job with the statement No sah, I has a quarter in my pocket already. With our forest resources slipping away five or six times-as fast as timber is being produced, it is no wonder- that the public is beginning to be aroused. Even those who have no thought for the future are having their eyes opened by current lumber prices, freight rates and the shortage of some classes of lumber

Preservative treatment of fence posts

One of the big expense bills that the Iowa farmer pays annually is for fence posts. If the 25,000,000 posts required each year for Iowa’s fences were set in one line and spaced a rod apart, they would build a fence three times around the earth at the equator; their cost would be nearly $4,000,000. That bill is so large because wooden posts, which are almost wholly used, are short lived. Yet numerous tests extending over many years made by the Iowa Agricultural Experiment station show that this heavy expense may be cut in two by preservative treatments which will lengthen the life of wooden posts from 3 to 25 years. One of the best indications of the economic value of wood preservation is found in the attitude of the railroads of the United States toward this work. Practically all of them are using cross ties treated by one of the several processes and a number of the larger companies have installed elaborate treating plants for doing their own work. They save immense sums of money annually by increasing the durability of ties and it is this item that appeals to the railroads. What is true regarding the durability of railroad ties under preservative treatment is largely true with fence posts. Both are subjected to decay, since both are used in contact with the soil. If the farmer can reduce his fence post charges by one-half or more, the saving effected is well worth his consideration

Renewing the Shelterbelt

In removing the old decaying shelterbelt and replacing it with younger and better trees, it is not necessary to lose its protective value during the process. By following any one of the methods described in this circular the old stand of trees may be cut out and a new stand of the same or some other species secured while keeping the shelterbelt in a more or less effective condition

Forestry and the Iowa Farmer

The fact that Iowa has such a preponderance of agricu1tural land sometimes is responsible for disregard of forest values in the state. In most land transactions in Iowa, the farms sell at a specified price per acre with no thought of classifying the forest and agricultural land. The poorer soils and rough forest areas are \u27\u27\u271umped in with the balance of the land at agricultural land prices. This practice has led the farmers to hold the wrong idea concerning actual forest land values as compared with agricultural values. In many sales it is quite difficult to make the land owner realize the relatively low value of forest soil as compared with agricultural land. This lack of balance between forest and agricultural land values has been prominently in evidence during the past several years in the purchase of state park lands in Iowa. In many cases areas of forest value only were held at agricultural prices which not only slowed up the purchase program of the State Conservation Board, but made condemnation proceedings necessary in certain cases

Wood-Using Industries of Iowa

The following brief report oil the wood-using industries of Iowa is based on returns from the various plants which manufacture wood into finished or partially finished products. The investigation does not take into account the large quantity of lumber which is used for rough construction work. Any products which are manufactured further than sawing or which go into a planing mill or sash and door factory are included