bluuebunny/crossref_metadata_2025_split huggingface dataset:
Technological Change and the Productivity Slowdown in Field Crops: United States, 1939-78
Authors: Thirtle Colin G. 
Published: July 2016

AbstractIn the past four decades, productivity in United States field crops has been transformed by the mechanical and fertilizer revolutions. Since input data are typically not available by crop, most investigations of productivity have been at the aggregate level. This paper develops a simultaneous equation, partial adjustment model of the demand for inputs, which generates estimates of the technical change parameters for wheat, corn, soybeans, and cotton. These estimates allow comparisons of the factor saving biases in technical change, leading to a novel test of the induced innovation hypothesis and the suggestion that the productivity slowdown may yet affect agriculture in the United States.
Market Failure in Multiphase Electric Power Development for Agricultural Irrigation
Authors: Tew Bernard V. , Broder Josef M. , Musser Wesley N. , Centner Terence J. 
Published: July 2016

AbstractThe adoption of multiphase electric power for electric irrigation has been limited in an area characterized by extremely rapid expansion of irrigated acreage despite production cost advantages. Theoretical and empirical evidence of failure in the existing market for multiphase power development are presented. Alternative development mechanisms are presented and discussed.
Financial Analysis of a Proposed Large-Scale Ethanol Cogeneration Project
Authors: Hanson Gregory D. 
Published: July 2016

AbstractFinancial analysis of an ethanol/electricity cogeneration plant indicates a rapid payback of investment and a high internal rate of return. This is primarily because cogeneration of steam for generation of electricity and biomass conversion to ethanol results in increased engineering efficiency compared to alternative ethanol alone production processes. Economic sensitivity testing included alternative price levels, interest rates, capacities, costs, and a “stand alone” case with no federal government excise tax subsidies. Supply and price analyses suggest the procurement of locally produced feedstock in Alabama and surrounding states is feasible. The robustness of the economic analysis provides support for consideration of ethanol cogeneration as a currently feasible strategy to utilize excess agricultural production capacity.
The Estate Tax Provision of the 1981 Economic Recovery Tax Act: Which Farmers Benefit?
Authors: Lowenberg-DeBoer J. , Boehlje Michael D. 
Published: July 2016

AbstractThis analysis used simulation to compare the cost of intergenerational transfer of farm estates under the pre-1981 tax rules and the Economic Recovery Tax Act of 1981 (ERTA) provisions. ERTA reduces transfer costs for almost all the estates considered. Large estates tend to benefit more than small estates if they qualify for use valuation or if they are large enough to be affected by the reduction in tax rates. ERTA does not create new forces for change in U.S. agriculture, but it tends to strengthen the tendency toward larger farm size and favor those who already own farm resources.
A Stochastic Programming Analysis of the Farm Level Implications of Soil Erosion Control
Authors: Segarra Eduardo , Kramer Randall A. , Taylor Daniel B. 
Published: July 2016

AbstractThis paper analyzes the effects of uncertain soil loss in farm planning models. A disaggregated approach was used because of an interest in examining the impact of probabilistic soil loss constraints on farm level decisionmaking. A stochastic programming model was used to consider different levels of probability of soil loss. Traditional methods of analysis are shown to consistently overestimate net returns.
Agribusiness Simulators for Management Training
Authors: Babb Emerson M. 
Published: July 2016

AbstractThis paper describes four agribusiness simulators which can be processed on a microcomputer for use in undergraduate and extension teaching. The simulators model the environment in which supermarket chains, farm supply centers, and cooperative and proprietary grain elevators compete for business. Instruction manuals, user's manuals, and a diskette are distributed for each simulator. Each diskette contains programs to enter and edit team decisions, to process decisions and print reports, and to create graphs of team performance. The simulators can be used to teach financial management concepts and techniques, as well as economic principles.
Financial Risk in Cotton Production
Authors: Wilson Paul N. , Gundersen Carl E. 
Published: July 2016

AbstractRisk analysis continues to emphasize price and yield variability as the principal components of the decisionmaker's risk environment. This research demonstrates the relative importance of financial risk for a representative cotton farm in Arizona. For highly leveraged operations, financial risk may account for 70 percent of the total risk faced by the producer. Implications for future risk analysis are discussed in light of these findings.
Establishing Linkages Between Economic Theory and Enterprise Budgeting for Teaching and Extension Programs
Authors: Bradford G. L. , Debertin D. L. 
Published: July 2016

AbstractAccounting techniques of farm enterprise budgeting are rarely linked to the axioms of static production theory and to capital theory. This paper illustrates how certain linkages may be established. Particular attention is given to handling problems of scale economies, optimal output levels, replacement of durable inputs, inflation, and technological change. Estimates in an illustrative budget are linked to specific points on average cost curves. Budgeting for representative farm situations is compared to budgeting for specific situations.
Economic Prospects for Sprinkle Irrigating Rice in Texas
Authors: Griffin Ronald C. , Rister M. Edward , Parker Michael R. , McCauley Garry N. 
Published: July 2016

AbstractThe economic feasibility of investing in sprinkler irrigation technology for rice production is investigated using linear programming and capital budgeting to identify the net annual benefits and net present value, respectively. Groundwater and both flat rate and volumetrically priced surface water sources of irrigation water are analyzed. Under typical practices occurring in rice production operations in the Texas Rice Belt, sprinkler irrigation technology is not profitable at current water costs. Producers using volumetrically priced surface water have the greatest incentive to consider sprinkler irrigation, but water prices must increase by over 250 percent for the investment in a sprinkler irrigation system to become attractive. Yield reductions associated with sprinkle-irrigated rice are a significant disincentive. For equivalent flood- and sprinkle-irrigated rice yields, an increase in water prices of over 175 percent is required before the investment in a sprinkler irrigation system becomes economically feasible.
Generic Advertising, Fob Price Promotion, and Fob Revenue: A Case Study of the Florida Grapefruit Juice Industry
Authors: Lee Jonq-Ying 
Published: July 2016

Each year many agricultural commodity groups spend millions of dollars advertising and promoting generic products. Generic advertising of a number of farm commodities occurs under federal authorization, under separate legislation or under marketing orders, or it is funded by producers on a voluntary contribution or mandatory basis.More than three-fourths of the advertising programs operating under separate federal legislation or marketing order authority have been initiated during the past ten years (Armbruster). In addition to existing advertising programs, several advertising programs authorized under federal legislation were voted down by producers in a referendum: the most recent case was a beef referendum.
Demand and Quality Uncertainty in Pecan Purchasing Decisions
Authors: Park Timothy A. , Florkowski Wojciech J. 
Published: July 2016

AbstractA generalized Heckman model of purchase decisions incorporating perceived consumer quality attributes, ease of purchase, and familiarity with marketing outlets as factors influencing pecan purchases is estimated. Marketing efforts that encourage consumers to expand expenditures on nut products increase both the probability of pecan purchases and the amount purchased. Consumers who use all types of nuts in a wider variety of foods tend to purchase pecans more frequently. A diverse set of marketing outlets provides consumers with convenient sources for purchasing pecans and has a significant influence on the probability of pecan purchases but not the amount of pecans purchased.
An Economic Analysis of a Corn-Soybean Crop Rotation Under Various Input Combinations in South Central Texas
Authors: Funk Robert D. , Mjelde James W. , Hons Frank M. , Saladino Vince A. 
Published: July 2016

AbstractEight input combinations of commercial fertilizer, insecticides, and herbicides on a corn-soybean crop rotation in the Brazos River Bottom of Texas are evaluated. Input combinations which do not fully utilize all three inputs are consistently ranked higher by all criteria as the preferred input strategy for the corn-soybean rotation system. These results, which indicate limited input crop rotations that fall somewhere between the extremes of conventional agricultural production and organic agriculture, deserve further attention as a possible production alternative.
Conservation Tillage and Pesticide Use in the Cornbelt
Authors: Fuglie Keith O. 
Published: July 2016

AbstractAdoption of conservation tillage can lead to substantial environmental benefits from reduced soil erosion. But benefits may be partially offset if adoption increases reliance on agricultural chemicals. Using area study data from the Cornbelt, this study examines factors affecting adoption of no-till and other conservation tillage systems and their effect on chemical use and corn yield. The results find no evidence that herbicide or fertilizer application rates are higher on fields with conservation tillage systems compared with conventional tillage. However, insecticide use may increase somewhat and yield may be lower. Current demographic trends in U.S. agriculture favor continued diffusion of conservation tillage.
The effects of temperature change and domestication on the body size of Late Pleistocene to Holocene mammals of Israel
Authors: Davis Simon J. M. 
Published: July 2016

Size variation among several species of large mammals is examined both throughout a wide geographical range today and within the Late Pleistocene-Holocene archaeo-faunal sequence of Israel. A regression of log dental size on environmental temperature produces similar negative slopes for recent Palaearctic foxes, wolves and boars as well as for Nearctic foxes. These species, and others which also exhibit an inverse correlation between size and temperature today, became dwarfed at the end of the Pleistocene in Israel. Abundant fossil gazelle and fox mensural data indicate that this diminution coincided with the temperature elevation 12,000 yr ago. Both the similarity of regression slopes for the recent material and the temporal coincidence of dwarfing among fossil species, representing different ecologies, strongly implicate temperature as the main body-size determining factor. Changes evidenced in the fossil record for boar, wolf and fox approximate a 15°C temperature change (Δt) based on their respective present-day size-temperature regressions. This Δt, if taken as an estimate for the eastern Mediterranean, is considerably higher than generally accepted values.An additional size reduction of aurochs, wolf and boar at the end of the Pleistocene or several millenia later is associated with their domestication. It may reflect man's preference for a large “head count” over individual large body size.
Skeletal Overgrowths Among Epizoans from the Silurian (Wenlockian) Waldron Shale
Authors: Liddell W. David , Brett Carlton E. 
Published: July 2016

Substrata for numerous epizoans in the Silurian Waldron Shale were provided by the toppled and overturned calyces of camerate crinoids. These were inhabited by a skeletonized fauna consisting of at least 25 species; including several bryozoans, tabulates, inarticulate brachiopods, worms, and echinoderms.Many of the encrusting bryozoans exhibit skeletal overgrowths which appear to reflect competitive interactions for space. Coexistence of certain of the bryozoans involved in such interactions is suggested by skeletal features such as inflated growth forms and upturned margins at junctions between colonies (both representing attempts to avoid being overgrown). In addition, the occurrence of overgrowth reversals within individual encounters indicates contemporaneity of that pair. Species may be ranked according to their relative overgrowth success; however, this ranking is far from rigid as lower ranked species may on occasion overgrow more highly ranked species. Such nontransitive patterns appear similar to those described from Recent cryptic bryozoan faunas.
A Turn in the Right Direction: Simulation of Erect Spiral Growth in the BryozoansArchimedesandBugula
Authors: McKinney Frank K. , Raup David M. 
Published: July 2016

Colonies of the fossil bryozoanArchimedesand erect, spiralled species of the living bryozoanBugulaconsist of wedge-shaped systems of radially diverging, bifurcated branches that extend from a helical axial margin. Morphology of these colonies may be simulated using few growth rules. These include 1) radius of the central helical margin (RAD), 2) rate of climb of central helical margin (ELEV), 3) radial angle between successive branches that originate from the central helical margin (ANG), 4) radial growth of all branches, 5) angle between branches and axis of central helical margin (BWANG), 6) distance between three adjacent, radially diverging branches at which the central branch bifurcates into two branches equally spaced between the two side branches (XMIN), and 7) placement of a spacing bar at base of newly bifurcated branches. In addition, size constraints on the simulations must be stipulated.Simulations are begun at a proximal point along the central helix where a radial branch originates and are “grown” in repetitive steps by extending the central helical margin a distance distally, determined by ANG, then censusing established branches for XMIN in order to bifurcate appropriate branches and extend others in several short growth increments, etc. Growth of branches ceases at stipulated maximum width, and growth of the entire simulation ceases at stipulated maximum height.The presence of a helical inner margin marked by uniformly spaced bifurcations generates the spiralled shape, i.e. ELEV must be a positive number. Values of RAD, ELEV (not zero), ANG and BWANG determine form of the spiral; the other growth rules apply to bifurcated unilaminate branch systems in general.The range of observed colony forms and hypothetical morphospace ofArchimedesmay be simulated by varying BWANG, XMIN, and ELEV. RAD was kept constant, as its variation would be redundant with XMIN and ELEV. Variation in ANG affects near-helix morphology, but its influence is undetectable beyond this zone. Variability within colonies may be simulated by assigning to each variable a standard deviation with mean-centered randomly chosen values for each decision.
The Theory of Evolution by Natural Selection: A Hierarchical Expansion
Authors: Arnold Anthony J. , Fristrup Kurt 
Published: July 2016

Alleles, individuals, and species are all examples of entities possessing variation in the properties that underlie natural selection: branching (reproduction), persistence (survivorship), and heritability of characters. This suggests that the logic embodied in the theory of natural selection can be abstracted from its usual application to the level of individuals to encompass selection operating among any biological entities for which these essential properties can be meaningfully defined. This approach leads to a unified perspective of adaptation, selection, and fitness at all levels. Expanded versions of the Price covariance selection equations provide a convenient and useful conceptual vehicle for this discussion. The advantages of a hierarchical approach are twofold: it permits exploration of concepts and ideas across levels by analogy, and it focuses attention upon the mechanisms that account for different evolutionary dynamics at each level rather than obscuring these biologically unique properties with argument by extension from a single “special” level.We point out that the choice of a single measure of evolutionary change restricts the context in which “other level” processes will be perceived. We illustrate the limited forms in which higher and lower level selection can be recognized from the unique perspective provided by any given level through extensions of Price's formula.An exploration of the implications of such an approach leads us to the assertion that the development of a unified theory of evolution demands the recognition and incorporation of hierarchical structure as a conceptual foundation.
Infaunal survival: alternative functions of shell ornamentation in the Bivalvia (Mollusca)
Authors: Stanley Steven M. 
Published: July 2016

Two kinds of adaptation aid infaunal bivalve mollusks in sustaining their life positions against potentially disruptive water movements: (1) ability to retard scour of surrounding sediment and (2) ability to reburrow rapidly if exhumed.The shell of the venerid Anomalocardia brasiliana is ornamented with concentric ridges that are asymmetrical in cross-section; experiments show that these ridges aid the animal in burrowing by gripping the sediment during backward rotation of the shell. The shell of the less deeply burrowing venerid Chione cancellata also bears concentric ridges, but these are symmetrical and experiments show that they hinder burrowing; other experiments demonstrate that these ridges reduce scour of sand from around a partly exposed animal. The single cardiid species Trachycardium egmontianum possesses adaptations comparable to those of the two venerid species, in the form of spines of two varieties; experiments show that the flared anterior spines facilitate burrowing and the cupped posterior spines reduce scour.Conspicuous ornamentation of the kinds considered here was rare throughout the Paleozoic. Its evolutionary deployment occurred primarily during the post-Paleozoic adaptive diversification of infaunal bivalves, which was triggered by the evolution of efficient burrowing mechanisms. The general premium on maintaining infaunal life positions was accentuated for bivalves after the Paleozoic by the origins of important modern predatory taxa.
Functional interpretation of lyre-shaped Bryozoa
Authors: McKinney Frank K. 
Published: July 2016

Colonies of Late Paleozoic lyre-shaped fenestrate bryozoans began growth on rigid substrates which were on the sea floor. After production of a basal disc, a fenestrate network developed in the shape of an erect bowed fan. The fenestrate fan was initially concave on the apertural side, but the curvature reversed a few millimeters above the base. Colonies were then separated along or just above the basal disc, and rested directly on the sea floor. The zooecial apertures were directed upward. The lateral margin of the fan grew to form the supporting struts of the soon-to-be lyre-shaped colony. An open vault formed below the upwardly bowed fan.Lyre-shaped colonies are interpreted to have lain on the sea floor so that each had the proximal end on the upcurrent side. Feeding zooids were on the upper surface and pulled water through their expanded tentacles. The filtered water passed through the fenestrules, into the vault, and out the open end of the vault, which was on the downcurrent side.
Some “laws” of gastropod shell form
Authors: Linsley Robert M. 
Published: July 2016

Five generalizations derived from the shell form of prosobranch gastropods are developed. (1) A univalve of more than one volution whose aperture lies in a plane that passes through the axis of coiling does not live with the aperture parallel to the substrate. (2) A univalve of more than one volution whose aperture lies in a plane that is tangential to the body whorl does live with the plane of the aperture parallel to the substrate. (3) Gastropods with tangential apertures, when extended, support the shell so that the center of mass of the shell and its contents is over the midline of the cephalopedal mass; this balancing of the shell may be accomplished either by regulatory detorsion, by inclination or by a combination thereof, to keep the center of gravity of the shell as low as possible. (4) Angulations or re-entrants in the gastropod aperture are usually indicative of inhalent or exhalent areas; inhalent areas are directed as far anteriorly as possible. (5) Gastropods having elongated apertures possess only a single gill and develop a water current through the mantle cavity from anterior to posterior along the long axis of the aperture; this axis is subparallel to the anterior-posterior axis of the foot.These generalizations are then used as the basis for some deductive interpretations of behavioral modes of Paleozoic Gastropoda.
The Mesozoic marine revolution: evidence from snails, predators and grazers
Authors: Vermeij Geerat J. 
Published: July 2016

Tertiary and Recent marine gastropods include in their ranks a complement of mechanically sturdy forms unknown in earlier epochs. Open coiling, planispiral coiling, and umbilici detract from shell sturdiness, and were commoner among Paleozoic and Early Mesozoic gastropods than among younger forms. Strong external sculpture, narrow elongate apertures, and apertural dentition promote resistance to crushing predation and are primarily associated with post-Jurassic mesogastropods, neogastropods, and neritaceans. The ability to remodel the interior of the shell, developed primarily in gastropods with a non-nacreous shell structure, has contributed greatly to the acquisition of these antipredatory features.The substantial increase of snail-shell sturdiness beginning in the Early Cretaceous has accompanied, and was perhaps in response to, the evolution of powerful, relatively small, shell-destroying predators such as teleosts, stomatopods, and decapod crustaceans. A simultaneous intensification of grazing, also involving skeletal destruction, brought with it other fundamental changes in benthic community structure in the Late Mesozoic, including a trend toward infaunalization and the disappearance or environmental restriction of sessile animals which cannot reattach once they are dislodged. The rise and diversification of angiosperms and the animals dependent on them for food coincides with these and other Mesozoic events in the marine benthos and plankton.The new predators and prey which evolved in conjunction with the Mesozoic reorganization persisted through episodes of extinction and biological crisis. Possibly, continental breakup and the wide extent of climatic belts during the Late Mesozoic contributed to the conditions favorable to the evolution of skeleton-destroying consumers. This tendency may have been exaggerated by an increase in shelled food supply resulting from the occupation of new adaptive zones by infaunal bivalves and by shell-inhabiting hermit crabs.Marine communities have not remained in equilibrium over their entire geological history. Biotic revolutions made certain modes of life obsolete and resulted in other adaptive zones becoming newly occupied.