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1. Adjusting Dynamic Models to Improve Their Predictive Ability

Author:
Richard J. Crom; Wilbur R. Maki
Source:
American journal of agricultural economics 1965 v.47 no.4 pp. 963-972
ISSN:
0002-9092
Subject:
agricultural economics; dynamic models; issues and policy
Abstract:
... Dynamic models are a valuable research tool for analysis and projection. However, cumulative error may build up sufficiently to make the model virtually useless for either purpose. Several adjustments in dynamic models intended to improve their predictive ability are presented in this paper along with criteria for making these adjustments. Examples of these adjustments are shown as they were used ...
DOI:
10.2307/1236337

2. Analysis of a Dynamic Model, with Particular Emphasis on Long‐Run Projections

Author:
Shlomo Reutlinger
Source:
American journal of agricultural economics 1966 v.48 no.1 pp. 88-106
ISSN:
0002-9092
Subject:
agricultural economics; dynamic models; econometric models; economists; equations; issues and policy; multipliers; students; supply balance
Abstract:
... The primary objective of this paper is to present to economists and students an efficient method for deriving long‐run projections of many interrelated economic variables. Several useful equilibrium concepts are given precise definition. A simple set of supply and demand equations is used to demonstrate that mathematical analysis of dynamic econometric models is a powerful tool for projecting futu ...
DOI:
10.2307/1236181

3. Dynamic Impact Multipliers: A Case Study of White Dry Edible Beans

Author:
Roger J. Vandenborre
Source:
American journal of agricultural economics 1968 v.50 no.2 pp. 311-327
ISSN:
0002-9092
Subject:
agricultural economics; case studies; dry beans; dynamic models; governmental programs and projects; market economy; market prices; multipliers
Abstract:
... A dynamic model for the white dry edible bean sector based upon empirical demand and supply relationships is used (1) to evaluate the impact of governmental support programs, (2) to study the impact which changes in the exogenous variables have on the system, and (3) to estimate the effects which support prices established above free market prices have on production. Unique aspects of this study a ...
DOI:
10.2307/1237544

4. Evaluating Supply Control Policies for Frozen Concentrated Orange Juice with an Industrial Dynamics Model

Author:
Richard C. Raulerson; Max R. Langham
Source:
American journal of agricultural economics 1970 v.52 no.2 pp. 197-208
ISSN:
0002-9092
Subject:
agricultural economics; dynamic models; economists; industry; issues and policy; markets; orange juice; profits and margins; trees
Abstract:
... Economists are increasingly being asked to study problems that require a systems approach. This paper reports an empirical application of industrial dynamics to a problem of an industry system. A second generation model was developed and used to appraise alternative supply control policies designed to reduce fluctuations in marketings of frozen concentrated orange juice and grower profits. Policie ...
DOI:
10.2307/1237490

5. Implicit Estimate of Residual Nitrogen Under Fertilized Range Conditions in the Northern Great Plains

Author:
M. S. Stauber; Oscar R. Burt
Source:
Agronomy journal 1973 v.65 no.6 pp. 897-901
ISSN:
0002-1962
Subject:
Agropyron cristatum; Bromus inermis; arid lands; costs and returns; dynamic models; equations; forage; grasses; hay; nitrogen; nitrogen fertilizers; nutrient availability; phosphorus fertilizers; semiarid zones; soil; soil-plant interactions; Great Plains region
Abstract:
... Information concerning carryover of fertilizer nitrogen in the plant-soil system is necessary to determine optimum fertilizer policies for dryland grasses in semiarid regions. A primary contribution of this paper is the presentation and illustration of a dynamic model for estimation of carryover nitrogen. The carryover relationship is estimated implicitly through yield response as opposed to direc ...
DOI:
10.2134/agronj1973.00021962006500060015x

6. Dynamic behavior model of ephemeral stream

Author:
Renard, K.G.; Laursen, E.M.
Source:
Journal of the Hydraulics Division. Proceedings of the American Society of Civil Engineers 1975 v.101 no.5 pp. 511-528
Subject:
mathematical models; dynamic models; sediment transport; stream channels; watershed hydrology; runoff; hydrologic models; Arizona
Abstract:
... Ephemeral stream hydraulic features are dynamic and respond to the variable streamflow available to move sediment. Streamflow varies both from the runoff-producing storms and transmission losses that decrease the runoff volume and peak. The channel profile in an ephemeral stream tends to be concave up because of the transmission losses and concave down because there is more flow downstream due to ...
Handle:
10113/8522

7. Feeding Rates and Population Growth

Author:
David J. Rapport; James E. Turner
Source:
Ecology 1975 v.56 no.4 pp. 942-949
ISSN:
0012-9658
Subject:
biotic potential; carrying capacity; choice feeding; dynamic models; energy; energy costs; foraging; population growth
Abstract:
... Numerous studies of natural populations have generated data relating foraging activities, the quantity and quality of available food resources, and population dynamics. In order to interpret these data we develop a comprehensive theorectical framework by constructing a model of foraging behavior and population growth in terms of energetic cost—gain functions. With total energy costs and gains of f ...
DOI:
10.2307/1936304

8. Foraging Movements of a Frugivorous Bat, Carollia perspicillata (Phyllostomatidae)

Author:
E. Raymond Heithaus; Theodore H. Fleming
Source:
Ecological monographs 1978 v.48 no.2 pp. 127-143
ISSN:
0012-9615
Subject:
Carollia; Neotropics; dynamic models; flight; foraging; frugivores; fruits; predation; radio telemetry; roots; statistical analysis; tropical forests; wet season
Abstract:
... The foraging movements of a Neotropical frugivorous bat (Carollia perspicillata)were studied to better understand its impact on the plants it disperses and the factors influencing its foraging behavior. Radio telemetry was used during 2 wet seasons to monitor the bats' movements in a Costa Rican seasonal tropical forest. We monitored 24 individuals for periods of up to 19 nights. This sample size ...
DOI:
10.2307/2937296

9. Markup Pricing in a Dynamic Model of the Food Industry

Author:
Dale M. Heien
Source:
American journal of agricultural economics 1980 v.62 no.1 pp. 10-18
ISSN:
0002-9092
Subject:
agricultural products; dynamic models; farms; food industry; prices; production technology
Abstract:
... This paper presents a dynamic model of farm and retail prices and quantities. Central to the model is the notion that increases in wholesale prices are transmitted to the retail level via markup‐type pricing behavior. This behavior is shown to be consistent with firm optimization under the assumption of constant returns to scale and Leontief production technology at the retail level. The markup hy ...
DOI:
10.2307/1239467

10. Optimal Regional Conjunctive Water Management

Author:
Jay E. Noel; B. Delworth Gardner; Charles V. Moore
Source:
American journal of agricultural economics 1980 v.62 no.3 pp. 489-498
ISSN:
0002-9092
Subject:
agricultural economics; basins; dynamic models; energy costs; groundwater; issues and policy; surface water; taxes; water management
Abstract:
... An optimal control model is used to determine the socially optimal spatial and temporal allocation of groundwater and surface water among agricultural and urban uses. The control model is described briefly and its advantages over other dynamic models are enumerated. Optimal rates of groundwater pumpage over the planning horizon were highly sensitive to increasing energy costs. Groundwater basins a ...
DOI:
10.2307/1240203

11. A Dynamic Model for Technical and Economic Analysis of Fertilizer Recommendations

Author:
Edgar A. Lanzer; Quirino Paris; William A. Williams
Source:
Agronomy journal 1981 v.73 no.4 pp. 733-737
ISSN:
0002-1962
Subject:
Glycine max; NPK fertilizers; Triticum aestivum; application rate; crop yield; dynamic models; economic analysis; equations; fertilizer application; field experimentation; linear programming; potassium fertilizers; prices; soil; soil fertility; soybeans; wheat; Brazil
Abstract:
... The rationale of this study was to jointly estimate response functions for N, P, and K for wheat and soybean cropping in southern Brazil and carryover functions for residual fertility. The two sets of functions were then combined in a dynamic model having general applicability for optimizing fertilizer recommendations. The model is composed of (a) a yield-nutrient response function incorporating L ...
DOI:
10.2134/agronj1981.00021962007300040040x

12. A Quantitative Genetic Theory of Life History Evolution

Author:
Russell Lande
Source:
Ecology 1982 v.63 no.3 pp. 607-615
ISSN:
0012-9658
Subject:
artificial selection; demography; dynamic models; evolution; fecundity; genetic correlation; life history; loci; mortality; phenotype; population growth; selection response; system optimization; topography
Abstract:
... Dynamic models of quantitative (polygenic) characters are more generally applicable in the analysis of life history evolution than are static optimization methods or one and two locus genetic models. A dynamic theory of life history evolution is derived by synthesizing population demography with quantitative genetics. In a population under weak selection with a nearly stable age distribution, the ...
DOI:
10.2307/1936778

13. Dynamic Modeling of the Eastern Gulf of Mexico Shrimp Fishery

Author:
Vito J. Blomo; John P. Nichols; Wade L. Griffin; William E. Grant
Source:
American journal of agricultural economics 1982 v.64 no.3 pp. 475-482
ISSN:
0002-9092
Subject:
agricultural economics; dynamic models; fisheries management; producer surplus; shrimp; shrimp fisheries; Gulf of Mexico
Abstract:
... The impact of alternative management schemes on the shrimp fishery of the eastern Gulf of Mexico is analyzed and compared to a baseline using simulation techniques. The fishery's biological and economic functions are modeled including intraseasonal shrimp growth rates, differences in demand for shrimp by size, and a heterogenous fishing fleet. Using consumer and producer surplus techniques, new fi ...
DOI:
10.2307/1240639

14. Inventory Adjustment and Dynamic Winery Behavior

Author:
Michael K. Wohlgenant
Source:
American journal of agricultural economics 1982 v.64 no.2 pp. 222-231
ISSN:
0002-9092
Subject:
agricultural economics; demand functions; dynamic models; inventories; markets; prices; wine industry; California
Abstract:
... This paper develops a dynamic model of processor behavior which is applied to the California wine industry. Price, production, and input demand functions are derived from an optimal control model which takes into account inventory growth from aging and the linkage between product inventories and input purchases. An important feature of the model is that expected future market conditions and beginn ...
DOI:
10.2307/1241126

15. Herb Cover Effects on Tree Seedling Patterns in a Mature Hemlock‐Hardwood Forest

Author:
Douglas A. Maguire; Richard T. T. Forman
Source:
Ecology 1983 v.64 no.6 pp. 1367-1380
ISSN:
0012-9658
Subject:
Acer rubrum; Betula; Dennstaedtia; Lycopodium; Oxalis; Prunus serotina; Tsuga canadensis; canopy; dynamic models; forest growth; forests; ground vegetation; herbs; leaves; light intensity; seedlings; soil pH; soil water; species diversity; summer; trees; West Virginia
Abstract:
... The role of herbs in affecting tree seedling patterns was investigated in an old—growth hemlock—hardwood forest in Cathedral State Park, West Virginia. Herb species cover, tree seedling density, and overhead foliage were sampled along with midsummer soil pH, soil moisture, and light intensity in 20 selected herb patches and 440 30 x 30 cm plots. Analyses of the patch data showed significant correl ...
DOI:
10.2307/1937491

16. Net Aerial Primary Production and Dynamics of Soil Organic Matter Formation in a Tidal Marsh Ecosystem

Author:
Y. P. Hsieh; O. J. Weber
Source:
Soil Science Society of America journal 1984 v.48 no.1 pp. 65-72
ISSN:
0361-5995
Subject:
Cladium mariscus subsp. jamaicense; air; biomass; carbon; carbon cycle; dynamic models; ecosystems; energy; primary productivity; salt marshes; soil; soil organic matter; submergence; Florida
Abstract:
... Relationships between net aerial primary production (NAPP) and soil organic matter formation in a tidal marsh environment were analyzed using a dynamic model. Four basic parameters were considered in the model: NAPP, disappearance rate of dead standing crop, and rates of plant decomposition in soil and air. The model was tested in a sawgrass (Cladium jamaicense) tidal marsh of north Florida. Net a ...
DOI:
10.2136/sssaj1984.03615995004800010012x

17. The Acquisition of Information and the Adoption of New Technology

Author:
Gershon Feder; Roger Slade
Source:
American journal of agricultural economics 1984 v.66 no.3 pp. 312-320
ISSN:
0002-9092
Subject:
agricultural economics; dynamic models; farmers; technology; India
Abstract:
... This paper presents a dynamic model of diffusion of a new technology involving a variable input. The model highlights the role of active information accumulation, which entails costs. It generates several hypotheses regarding the likely pattern of adoption and use of the variable input over time by farmers of differing holding sizes and different access to information. It provides a possible expla ...
DOI:
10.2307/1240798

18. A Dynamic Analysis of Marketing Orders, Voting, and Welfare

Author:
Peter Berck; Jeffrey M. Perloff
Source:
American journal of agricultural economics 1985 v.67 no.3 pp. 487-496
ISSN:
0002-9092
Subject:
agricultural economics; dynamic models; farmers; marketing; profit maximization
Abstract:
... This paper presents a dynamic model of how profit‐maximizing farmers would vote on marketing order rules given that new firms will enter, based on rational expectations (perfect foresight) about the path profits follow. Early entrants make large short‐run gains while, in the long run, marginal firms break even. Welfare analyses under a dynamic model differ substantially from the static analyses no ...
DOI:
10.2307/1241067

19. Obtaining empirical equations for the process of formation-decomposition of FeEDDHA in soils

Author:
Sanchez-Andreu, J.; Juarez, M.; Fortun, A.
Source:
Communications in soil science and plant analysis 1985 v.16 no.12 pp. 1259-1269
ISSN:
0010-3624
Subject:
calcareous soils; chelates; soil fertility; nutrient availability; dynamic models; Spain
DOI:
10.1080/00103628509367684

20. Soil temperature and the energy balance of vegetative mulch in the semi-arid tropics. II. Dynamic analysis of the total energy balance

Author:
Ross, P.J.; Williams, J.; McCown, R.L.
Source:
Soil research 1985 v.23 no.4 pp. 515-532
ISSN:
0004-9573
Subject:
soil temperature; mulches; mulching; energy balance; tillage; heat transfer; dynamic models; soil water content; seedlings; evaporation; tropics; semiarid zones; Queensland
DOI:
10.1071/SR9850515