Evaluating the methodology of social experiments

Welfare ; Econometric models

Florida\u27s Cattle Culture: Ethos And Enterprise In The Sunshine State

Cattle ranching has been of major significance to Florida since the 16th century; however, few are aware of the historic, ecologic, economic and cultural influence of this industry. This study investigates the origins and impacts of the traditional customs and practices of Florida’s cattle ranchers, who preserve and reinvent this rich heritage today. Ranchers live closely with the land and their animals and, due to the often-uncertain and cyclical nature of the business, must possess resourcefulness and initiative to prosper. The image of the stoic cowboy has long been associated with the American West, yet before longhorn cattle ever crossed the western plains, Florida frontiers were populated with herds of unique “cracker” cows, descendants of cattle left behind by early Spanish settlers. Like the West, Florida experienced conflicts between ranchers and other land claimants, issues that continue in the 21st century. Modern ranchers contend with developers, environmental concerns, and increasing regulation, yet they persevere in passing on their cultural heritage. Agricultural lifestyles can be emotionally fulfilling, but stewardship of land and animals can be stressful and labor-intensive. Motivation to continue these customs may be enhanced by identification with cowboys of popular American media, enhanced by physical immersion in a similar setting. Optimal agricultural practices have been well researched; however, anthropology provides a useful lens to examine customs and practices of Florida’s cattle ranchers. Anthropologists have long been concerned with the dynamic relationship between human culture and the environment, examining how the physical landscape and ecological niches shape and are shaped by those who inhabit them. As globalized trade markets, technology, and economies expand, influencing agricultural practices and destroying natural habitats, diachronic studies of changing environments, economic and sociocultural influences in geographically bounded locales can be helpful in understanding this process. iv However, a key consideration is the fact that culture is not static, but ever changing, thus the most important aspects of tradition and heritage that we choose to retain and reinvent may provide the most telling insight into any societ

Autonomous RPRV Navigation, Guidance and Control

Dryden Flight Research Center has the responsibility for flight testing of advanced remotely piloted research vehicles (RPRV) to explore highly maneuverable aircraft technology, and to test advanced structural concepts, and related aeronautical technologies which can yield important research results with significant cost benefits. The primary purpose is to provide the preliminary design of an upgraded automatic approach and landing control system and flight director display to improve landing performance and reduce pilot workload. A secondary purpose is to determine the feasibility of an onboard autonomous navigation, orbit, and landing capability for safe vehicle recovery in the event of loss of telemetry uplink communication with the vehicles. The current RPRV approach and landing method, the proposed automatic and manual approach and autoland system, and an autonomous navigation, orbit, and landing system concept which is based on existing operational technology are described

A simultaneous equation analysis of selected terminal hog markets

For many years, terminal hog markets have served as price reflecting points for the rest of the hog economy, reflecting market conditions for hogs. During the last decade, however, the percentage of packers’ purchases made from terminal markets has declined from about thirty percent to approximately eighteen percent, while direct buying and purchases through auction markets have increased. As the volume of hogs traded in terminal markets declines, the protection of consumers' welfare, as well as that of farmers and packers, becomes increasingly important since equilibrium prices and quantities for such markets may not be competitively determined. Fresh egg markets of a few years ago offer an example of how markets can lose their role as price reflecting points when their volume of trade falls to a small percentage of total trade. In looking to the future, Breimyer (1970) emphasized the important role of terminal markets in noting that In all the economy if not all society, certain persons and institutions and practices become virtually a proxy for a larger body... In livestock marketing, there must be a central value determining mechanism if we are to have an exchange system. Total decentralization is bedlam and unworkable. Even as central markets fade out of the limelight, I find it necessary to defend their significant role. They have served as the price making mechanism, or a big part of it, for a much larger volume of trading than actually takes place on the markets themselves. In spite of their importance, terminal hog markets have received little attention separate from the rest of the hog economy. Although the relative volume handled by terminal markets has been declining, their role in the pricing of hogs may even be increasing. For example, production of slaughter hogs has become and is becoming more coordinated and integrated vertically. A current form of closer coordination in the production and marketing of hogs are contractual agreements between producers of hogs and various corporations. These contracts differ depending upon whom the contracting corporation is, but the general purpose of the contracts is to stabilize hog supplies so that the buyers and sellers may operate under less uncertainty, whether the buyer be a feed manufacturer or a packer. Diverse as these contracts may be, they usually involve at some stage of production the purchase or sale of hogs whose price is determined by the current slaughter hog price at a specified terminal market. As the incidence of such agreements increases, the importance of terminal markets as price reflecting points may be expected to increase. Should the importance of terminal hog markets in the value determining mechanism increase, should these markets become proxies for many buyers and sellers, understanding the structure of these markets may become crucial to the protection of consumers’ welfare. This study sought to help provide such an understanding. The purpose of this paper was to describe the structure of demand and supply for slaughter hogs, on a monthly basis, at eight terminal markets. Structure was used in an econometric sense, i.e., a model with each equation representing an autonomous sector of an economic problem, such as demand and supply, with parameters having specific values. The markets studied were Chicago, Indianapolis, Kansas City, Omaha, St. Louis, Sioux City, South St. Joseph, and South St. Paul. An effort was made to specify demand and supply relationships in accordance with those established in the agricultural economics literature, so that the usefulness of these relationships in understanding the monthly behavior of terminal markets might be determined empirically. This literature is surveyed in the following chapter. In accordance with this literature, a model of the demand for and supply of slaughter hogs is presented in Chapter III. For each of the eight markets, demand and supply equations were estimated by applying three-stage least squares to the principal components of the predetermined variables. The theory behind this estimation procedure is presented in Chapter IV. Then in Chapter V, the results of the analysis are presented, followed by conclusions in Chapter VI.Includes bibliographical references

40Ar/39Ar ages of lunar impact glasses: Relationships among Ar diffusivity, chemical composition, shape, and size

Lunar impact glasses, quenched melts produced during cratering events on the Moon, have the potential to provide not only compositional information about both the local and regional geology of the Moon but also information about the impact flux over time. We present in this paper the results of 73 new 40Ar/39Ar analyses of well-characterized, inclusion-free lunar impact glasses and demonstrate that size, shape, chemical composition, fraction of radiogenic 40Ar retained, and cosmic ray exposure (CRE) ages are important for 40Ar/39Ar investigations of these samples. Specifically, analyses of lunar impact glasses from the Apollo 14, 16, and 17 landing sites indicate that retention of radiogenic 40Ar is a strong function of post-formation thermal history in the lunar regolith, size, and chemical composition. Based on the relationships presented in this paper, lunar impact glasses with compositions and sizes sufficient to have retained 90% of their radiogenic Ar during 750 Ma of cosmic ray exposure at time-integrated temperatures of up to 290 K have been identified and are likely to have yielded reliable 40Ar/39Ar ages of formation. Additionally, ~50% of the identified impact glass spheres have formation ages of <500 Ma, while ~75% of the identified lunar impact glass shards and spheres have ages of formation <2000 Ma. The observed age-frequency distribution of lunar impact glasses may reflect two processes: (i) diminished preservation due to spontaneous shattering with age; and (ii) preservation of a remnant population of impact glasses from the tail end of the terminal lunar bombardment having 40Ar/39Ar ages up to 3800 Ma. A protocol is described for selecting and analyzing lunar impact glasses.Comment: Please contact Zellner ([email protected]) for data tables and other supplemental informatio

Identification of the Active-Site Residues of the 3C Proteinase of Foot-and-Mouth Disease Virus

AbstractTo identify the active-site residues of the 3C proteinase of foot-and-mouth disease virus (FMDV), we introduced mutations into the 3C coding region and examined the activity of mutant enzymes on various substrates. Based on alignment of FMDV 3C with other picornavirus 3C proteinases and with the trypsin family of serine proteinases, mutations were introduced at residues presumed to be part of the catalytic triad, involved in substrate binding, or present in nonconserved regions. Wild-type and mutant 3C proteins were expressed inEscherichia coliand tested for their ability to cleave synthetic substrates corresponding to different portions of the viral genome. Substitutions at His-46 (catalytic triad), Asp-84 (catalytic triad), or His-181 (substrate binding) produced enzymes unable to process P1, P2, or P3 substratesin trans,whereas a change in the conserved Asp-98 had no effect on enzyme activity. Substitution of Ser for Cys-163 (catalytic triad) yielded an enzyme that retained activity on some substrates, while a substitution of Gly at this position resulted in a completely inactive enzyme. The kinetics oftransprocessing of translation products from a transcript encoding the P1 and P2 coding regions and the 2C/3A cleavage site with wild-type 3C or a transcript encoding P1 with 3C mutants revealed that the order of cleavage was VP3-VP1, VP0-VP3, VP1-2A, 2C-3A, and 2B-2C. Mutations in 3C that resulted in a partially active enzyme were individually introduced into full-length FMDV cDNA and RNA transcripts were translated in a cell-free system and used to transfect cells. In all cases the virus that was rescued had reverted to the wild-type 3C codon

Maximum Entropy and Bayesian Data Analysis: Entropic Priors

The problem of assigning probability distributions which objectively reflect the prior information available about experiments is one of the major stumbling blocks in the use of Bayesian methods of data analysis. In this paper the method of Maximum (relative) Entropy (ME) is used to translate the information contained in the known form of the likelihood into a prior distribution for Bayesian inference. The argument is inspired and guided by intuition gained from the successful use of ME methods in statistical mechanics. For experiments that cannot be repeated the resulting "entropic prior" is formally identical with the Einstein fluctuation formula. For repeatable experiments, however, the expected value of the entropy of the likelihood turns out to be relevant information that must be included in the analysis. The important case of a Gaussian likelihood is treated in detail.Comment: 23 pages, 2 figure

A revised asteroid polarization-albedo relationship using WISE/NEOWISE data

We present a reanalysis of the relationship between asteroid albedo and polarization properties using the albedos derived from the Wide-field Infrared Survey Explorer. We find that the function that best describes this relation is a three-dimensional linear fit in the space of log(albedo)-log(polarization slope)-log(minimum polarization). When projected to two dimensions the parameters of the fit are consistent with those found in previous work. We also define p* as the quantity of maximal polarization variation when compared with albedo and present the best fitting albedo-p* relation. Some asteroid taxonomic types stand out in this three-dimensional space, notably the E, B, and M Tholen types, while others cluster in clumps coincident with the S- and C-complex bodies. We note that both low albedo and small (D<30 km) asteroids are under-represented in the polarimetric sample, and we encourage future polarimetric surveys to focus on these bodies.Comment: 16 pages, Accepted to Ap