Prices of farm products in Iowa, 1851-1940

The need for local farm product prices for a long period of time is generally conceded, since numerous problems in agricultural economics depend for their solution upon the existence of adequate and accurate farm product price series. Terminal market prices are suitable for many purposes, but for studies of local significance it is necessary that farm price averages be available. No attempt will be made in this bulletin to develop any of the possible uses of a price series. Their actual applications may be so varied that any treatment given here would necessarily be inadequate. Rather, the intent is to furnish a long time series of prices which may be used for any occasion requiring historical prices. An historical record of material, which has been compiled at great expenditures of time and effort, has been brought together in table form ready to be employed on inquiries concerned with prices

Some investigations on the suitability of the township as a unit for sampling Iowa agriculture

The purpose of this study was to determine a sampling procedure by which agricultural information may be efficiently obtained for areas smaller than the state, particularly the county. This study, therefore, is one of a series (2) (4) directed toward the problems of methodology of an agricultural sample-census. The objectives (8) of such a sample-census are: To obtain useful information (a) more frequently (annually instead of quinquennially, as at present), (b) of greater extent (include items not covered by the regular census) and (c) at greater economy. Consequently the sample-census is proposed at least in part to supplement the regular census in providing the information needed in the analysis and understanding of special agricultural problems arising in the field of policy and programs, such as farm tenancy, soil conservation, etc. This study, however, is limited to an investigation of merely a few of the many problems of sample-census procedure. Here we are interested primarily in the following questions: 1. Is it possible to find a township or group of townships within a county which will satisfactorily represent that county for a period of years? 2. For a given degree of accuracy, how large must a sample he for (a) a county, (b) a crop-reporting district (a group of about 10 counties)? 3. Are there any satisfactory criteria by which a county may be stratified and thereby increase sampling efficiency? This study provides, we believe, some aid in answering these and allied questions

How Do Farmers Want to Market Their Hogs?

Midwest farmers in general have three choices in marketing their hogs; They can sell them live weight, priced with relatively little grading. They can sell them by live weight with more careful grading. Hogs can be priced according to carcass weight and grade

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Consumer preferences for pork, Des Moines, Iowa

The declining demand for pork is of concern to the residents of Iowa and the other states where pork production is important. To determine consumer preferences and attitudes regarding pork and to obtain information on factors affecting consumption of pork and other meats, a probability sample of households in Des Moines, Iowa was selected for interview. An interview was obtained during June 1955 from the person in each of 499 households who generally bought the meat for the family. Income and family size were the principal determinants of pork consumption patterns among the survey households. For a given income, total pork consumption increased sharply as the size of family increased. As income increased for a given size of household, however, pork consumption gradually declined. No differences related to occupation were detected

Electron Spin Dynamics and Hyperfine Interactions in Fe/Al_0.1Ga_0.9As/GaAs Spin Injection Heterostructures

We have studied hyperfine interactions between spin-polarized electrons and lattice nuclei in Al_0.1Ga_0.9As/GaAs quantum well (QW) heterostructures. The spin-polarized electrons are electrically injected into the semiconductor heterostructure from a metallic ferromagnet across a Schottky tunnel barrier. The spin-polarized electron current dynamically polarizes the nuclei in the QW, and the polarized nuclei in turn alter the electron spin dynamics. The steady-state electron spin is detected via the circular polarization of the emitted electroluminescence. The nuclear polarization and electron spin dynamics are accurately modeled using the formalism of optical orientation in GaAs. The nuclear spin polarization in the QW is found to depend strongly on the electron spin polarization in the QW, but only weakly on the electron density in the QW. We are able to observe nuclear magnetic resonance (NMR) at low applied magnetic fields on the order of a few hundred Oe by electrically modulating the spin injected into the QW. The electrically driven NMR demonstrates explicitly the existence of a Knight field felt by the nuclei due to the electron spin.Comment: 19 Figures - submitted to PR