Basis Convergence in Cattle Contracts Before and After Changes to Delivery Specifications

Livestock Production/Industries, Marketing,

A generalized Schroedinger equation for loop quantum cosmology

A temporally discrete Schroedinger time evolution equation is proposed for isotropic quantum cosmology coupled to a massless scalar source. The approach employs dynamically determined intrinsic time and produces the correct semiclassical limit.Comment: 5 pages, to appear in the Proceedings of the Eleventh Marcel Grossmann Meetin

Design of a reconfigurable modular manipulator system

Using manipulators with a fixed configuration for specific tasks is appropriate when the task requirements are known beforehand. However, in less predictable situations, such as an outdoor construction site or aboard a space station, a manipulator system requires a wide range of capabilities, probably beyond the limitations of a single, fixed-configuration manipulator. To fulfill this need, researchers have been working on a Reconfigurable Modular Manipulator System (RMMS). Researchers have designed and are constructing a prototype RMMS. The prototype currently consists of two joint modules and four link modules. The joints utilize a conventional harmonic drive and torque motor actuator, with a small servo amplifier included in the assembly. A brushless resolver is used to sense the joint position and velocity. For coupling the modules together, a standard electrical connector and V-band clamps for mechanical connection are used, although more sophisticated designs are under way for future versions. The joint design yields an output torque to 50 ft-lbf at joint speeds up to 1 radian/second. The resolver and associated electronics have resolutions of 0.0001 radians, and absolute accuracies of plus or minus 0.001 radians. Manipulators configured from these prototype modules will have maximum reaches in the 0.5 to 2 meter range. The real-time RMMS controller consists of a Motorola 68020 single-board computer which will perform real time servo control and path planning of the manipulator. This single board computer communicates via shared memory with a SUN3 workstation, which serves as a software development system and robot programming environment. Researchers have designed a bus communication network to provide multiplexed communication between the joint modules and the computer controller. The bus supports identification of modules, sensing of joint states, and commands to the joint actuator. This network has sufficient bandwidth to allow servo sampling rates in excess of 500 Hz

The Implicit Value of Irrigation Through Parcel Level Hedonic Price Modeling

This paper relies on data associated 2,100 agricultural land sale transactions across two major Nebraska Watersheds (the Republican and Central Platte) over the 2000 to 2008 time period. The sales were spatially referenced (digitized into a GIS) in order to quantify and geo-spatially predict and map the implicit values of irrigation through the use of hedonic price modeling. Marginal implicit prices vary substantially across subwatersheds (natural resource districts), and the contribution of irrigation to sale prices is directly related to the extent to dependency of production agriculture on irrigation. This information is now currently being used to evaluate the economic efficiency of recent irrigation retirement programs and to help ensure that current and future retirement programs are cost-effective through targeting that retires irrigation land with the greatest hydrologic impact on water resources for the lowest cost.Farm Management, Production Economics, Resource /Energy Economics and Policy,

Acoustically swept rotor

Impulsive noise reduction is provided in a rotor blade by acoustically sweeping the chord line from root to tip so that the acoustic radiation resulting from the summation of potential singularities used to model the flow about the blade tend to cancel for all times at an observation point in the acoustic far field

MINIVER upgrade for the AVID system. Volume 2: LANMIN input guide

In order to effectively incorporate MINIVER into the AVID system, several changes to MINIVER were made. The thermal conduction options in MINIVER were removed and a new Explicit Interactive Thermal Structures (EXITS) code was developed. Many upgrades to the MINIVER code were made and a new Langley version of MINIVER called LANMIN was created. A user input guide for LANMIN is provided

EFFECT OF GENERIC ADVERTISING ON THE DEMAND FOR FLUID MILK: THE CASE OF THE TEXAS MARKET ORDER

This analysis indicates that generic advertising expenditures, ceteris paribus, generated rightward shifts in demand for fluid milk in the Texas Market Order over the period January 1980 to September 1988. Generally, the results from this study are in agreement with previous research efforts which suggest that generic advertising can increase the demand for fluid milk. Importantly, in this analysis, the impacts of television and radio advertising have been effectively disentangled. Television advertising generates a response that wears off more quickly than radio advertising. Also, the long-run effect of radio advertising is bout 1.75 times greater than the long-run effect of television advertising.Demand and Price Analysis, Marketing,

IMPACT OF CHANGING CONSUMER PREFERENCES ON WILLINGNESS-TO-PAY FOR BEEF STEAKS

Consumer/Household Economics,

Optical spectroscopy study on pressure-induced phase transitions in the three-dimensional Dirac semimetal Cd3_3As2_2

We report a room-temperature optical reflectivity study performed on [112]-oriented Cd$_3$As$_2$ single crystals over a broad energy range under external pressure up to 10 GPa. The abrupt drop of the band dispersion parameter ($z$-parameter) and the interruption of the gradual redshift of the bandgap at $\sim$4~GPa confirms the structural phase transition from a tetragonal to a monoclinic phase in this material. The pressure-induced increase of the overall optical conductivity at low energies and the continuous redshift of the high-energy bands indicate that the system evolves towards a topologically trivial metallic state, although a complete closing of the band gap could not be observed in the studied pressure range. Furthermore, a detailed investigation of the low-pressure regime suggests the possible existence of an intermediate state between 2 and 4~GPa , that might be a precursor of the structural phase transition or due to the lifted degeneracy of the Dirac nodes. Several optical parameters show yet another anomaly at 8~GPa, where low-temperature superconductivity was found in an earlier study.Comment: submitted to PR

FOOD NUTRITIONAL QUALITY: A PILOT STUDY ON CONSUMER AWARENESS

Retail food demand studies are becoming increasingly concerned with the role of nutrition and health, yet consumer perceptions and attitudes are often ignored. The purpose of this pilot study is to determine consumer perceptions involving nutrition levels for selected foods. The influence of demographics and information about nutrition and health on perceptions toward meat items are determined. Results generally indicate that consumer perceptions toward fat and cholesterol levels in meats are based on the comparison of animal sources, not the comparison of individual cuts or preparation techniques. Recent efforts in the study of retail food demand have moved toward the role of nutrition and health. Several attempts have been made to measure the role that nutrition plays in food value or purchase habits (LaFrance (1983), Huffman (1988), Brown and Shrader (1990)). These studies use actual nutritional content of foods consumed to estimate demand impacts. However, it is possible that consumers perceive the nutritional elements of certain foods to be significantly different than actual levels. Differences between actual and perceived levels represent measurement error in these variables. Such errors may adversely affect the results of our demand studies. Consumer misperceptions may be an especially important issue when a utility maximization model such as Lancaster's Consumer Goods Characteristics Model (CGCM) is used. In such a model, the utility function arguments are the characteristics of the goods not the goods themselves. If consumers misperceive the nutritional value of food products, such models should include the perceived levels of nutrition, not the actual levels. The CGCM has been used extensively in recent years. In particular, CGCM was used by Ladd and Suvannant (1976) to test if food prices were a sum of the values of certain nutrients; by Adrian and Daniels (1976) to estimate nutrient demand based in part on demographic variables; by Morgan, Metzen, and Johnson (1979) to estimate hedonic prices for breakfast cereal characteristics; and by Terry, Brooker, and Eastwood (1986) to estimate the demand for nutrients. Each of these studies used actual nutrition levels. If, however, perceived nutrition levels are different than the actual levels, the results and conclusions may be affected. Results from these models vary widely. In the case of some nutrients, the implicit values can switch from significantly positive to significantly negative across models. Some of the variability may be associated with specification and differences in time periods. However, some variation may result from differences in perceptions which also change over time. Models which do not directly specify nutrient levels may fall prey to another problem. Work by Brown and Schrader (1990) and later by Capps and Schmitz (1990) utilize an index of nutritional awareness. Models of this nature allow for consumer perceptions to be included. However, when results of these models are reviewed, the results are compared to actual data, not perceptions. These results may be compared to the wrong benchmarks. Thus perceptions need to be considered, regardless of the approach used.Food Consumption/Nutrition/Food Safety,