bluuebunny/crossref_metadata_2025_split huggingface dataset:
Excitatory inputs to spiny cells in layers 4 and 6 of cat striate cortex
Authors: Bannister N.J. , Nelson J.C. , Jack J.J.B. 
Published: March 2003

The principal target of lateral geniculate nucleus in the cat visual cortex is the stellate neurons of layer 4. In previously reported work with intracellular recording and extracellular stimulation in slices of visual cortex, three general classes of fast excitatory synaptic potentials (EPSPs) in layer 4a spiny stellate neurons were identified. One of these classes, characterized by large and relatively invariant amplitudes (mean 1.7 mV, average coefficient of variation (CV) 0.083) were attributed to the action of geniculate axons because, unlike the other two classes, they could not be matched by intracortical inputs, using paired recording. We have examined in detail the properties of this synaptic input in twelve examples, selecting for study those EPSPs where there was secure extracellular stimulation of the single fibre input to a pair of stimuli 50 ms apart. In our analysis, we conclude that the depression that these inputs show to the second stimulus is entirely postsynaptic, since the evidence strongly suggests that the probability of transmitter release at the synaptic site(s) remains 1.0 for both stimuli. We argue that the most plausible explanation for this postsynaptic depression is a reduction in the average probability of opening the synaptic channels. Using a simple biochemical analysis (c.f. Sigworth plot), it is then possible to calculate the number of synaptic channels and their probability of opening, for each of the 12 connections. The EPSPs had a mean amplitude of 1.91 mV (±1.3 mV SD) and a mean CV of 0.067 (± 0.022). The calculated number of channels ranged from 20 to 158 (59.4 ± 48.7) and their probability of opening to the first EPSP had an average of 0.83 (± 0.09), with an average depression of the probability to 0.60 for the second EPSP.
Geniculate afferents also terminate in layer 6. Intracellular recordings were also made in the upper part of this layer and a total of 51 EPSPs were recorded from pyramidal cells of three principal types. Amongst this dataset we sought EPSPs with similar properties to those characterized in layer 4a. Three examples were found, which is a much lower percentage (6%) than the incidence of putative geniculate EPSPs found in layer 4a (42%).
Is Part‐Time Farming Really a Step in the Way Out of Agricultural?
Authors: Kimhi Ayal 
Published: March 2003

AbstractOne of the most important questions regarding the phenomenon of part‐time farming is whether it is a stable situation or just a step in the way out of agriculture. This article provides support for the first possibility in the context of Israeli family farms in the 1970s. A multinomial logit model of work choices is estimated, including estimated transition probabilities among the explanatory variables. The results indicate that a high objective probability of exit from farming within the next decade decreased the tendency to engage in off‐farm work, especially in a full‐time job, in 1971.
The Output Decision of a Risk‐Neutral Producer under Risk of Liquidation
Authors: Mahul Oliver 
Published: March 2003

AbstractA risk‐neutral producer faces liquidity constraint that forces him to liquidate real assets in imperfect markets if he cannot meet his cash obligation, entailing a fixed liquidation cost. Under this risk of liquidation, the risk‐neutral producer is shown to refuse to undertake a risky project with positive expected excess return, exhibiting first‐order risk aversion. The optimal output level of the producer is piecewise linear in wealth; it decreases or increases depending on whether the expected excess return is positive or negative. The producer's apparent utility function exhibits an S‐shaped curve when the initial liquid assets are affected by a background risk that is normally distributed.
Does Market Timing Contribute to the Cattle Cycle?
Authors: Hamilton Stephen F. , Kastens Terry L. 
Published: March 2003

AbstractRecent evidence suggests that cyclical cattle inventories are driven by exogenous shocks. This article examines a second possible contributing factor to the cattle cycle: a market timing effect that arises from individual attempts to maintain countercyclical inventories. The model uncovers an important conceptual point: to the extent that cycles are driven by exogenous shocks, a representative producer should outperform one who maintains a constant inventory; whereas, for cycles induced by market timing, a representative producer should underperform one with a constant inventory. Simulated net returns over 1974−98 reveal that a constant‐inventory manager significantly outperformed the representative U.S. producer, which indicates that market timing influences the cattle cycle.
The Economics of Livestock Waste and Its Regulation
Authors: Innes Robert 
Published: March 2003

AbstractThis article develops a spatial model of regional livestock production and three attendant environmental effects: spills from animal waste stores;nutrient runoff due to the application of manure to croplands; and direct ambient pollution, including odors, pests, and gases. Assuming that neither environmental outcomes nor operators' manure‐spreading practices can be monitored and regulated, constrained efficient production arrangements and waste‐handling practices are described. The efficiency effects of several regulatory policies are then explored, including (a) scale regulations that limit animal inventories, (b) chemical fertilizer taxes, and (c) waste storage and handling standards that affect storm protections and manure transport.
Hedonic Prices for Fish: Tuna Prices in Hawaii
Authors: McConnell Kenneth E. , Strand Ivar E. 
Published: March 2003

AbstractOver the past two decades, the marketing of fish has recognized the importance of quality. Yet empirical analysis of market transactions could give us little insight into the value of different qualities of fish because market data are typically aggregated. We exploit a dataset on the auction price of tuna sold in Hawaii to estimate a hedonic model. The model provides empirical estimates of price increments due to species, quality of the fish such as size or fat content, method of handling, and market conditions. The empirical results are also used to estimate price flexibilities for landings in Hawaii.
Inventory Dynamics under Transaction Costs
Authors: Chavas Jean‐Paul , Despins Paula M. , Fortenbery T. Randy 
Published: March 2003

AbstractA conceptual model of storage behavior is developed. Optimal intertemporal pricing is derived to analyze the effects of transaction costs on storage andarbitrage pricing. It is shown how transaction costs can rationalize the existence of an inverse carrying charge for inventory. The model is applied to U.S. soybeans stocks for the period 1960–95. The empirical results suggest that transaction costs have a significant influence on storage behavior andintertemporal arbitrage pricing.
An Analysis of Occupational Health in Pork Production
Authors: Hurley Terrance M. , Kliebenstein James B. , Orazem Peter F. 
Published: March 2003

AbstractData on attendees at the World Pork Expo from 1991–95 are used to evaluate the impact of farming generally, and hog farming and confinement operations more specifically, on the measured health outcomes of participants. Hog farming is found to increase risk of reduced hand strength and respiratory symptoms. To the extent these health risks are known, hog farmers will require a compensating differential to reward them for accepting a greater risk, an outcome consistent with higher long‐term returns for hog production relative to cash‐grain production.
Cumulative Effects and Optimal Targeting of Conservation Efforts: Steelhead Trout Habitat Enhancement in Oregon
Authors: Wu JunJie , Adams Richard M. , Boggess William G. 
Published: March 2003

AbstractA major problem with some conservation programs is that they ignore potential cumulative (threshold) effects in environmental quality management. The objective of this study is to investigate the importance of cumulative effects in the targeting of conservation efforts. The empirical focus is on habitat investments to protect an important anadromous fish species in the Pacific Northwest, steelhead trout. Results of the analysis point to a substantial cumulative effect in the relationship between water quality and abundance in this fishery, which affects the efficiency of specific habitat investments.
Survey Response‐Related Biases in Contingent Valuation: Concepts, Remedies, and Empirical Application to Valuing Aquatic Plant Management
Authors: Messonnier Mark L. , Bergstrom John C. , Cornwell Christopher M. , Teasley R. Jeff , Cordell H. Ken 
Published: March 2003

AbstractSample nonresponse and selection biases that may occur in survey research such as contingent valuation applications are discussed and tested. Correction mechanisms for these types of biases are demonstrated. Results indicate the importance of testing and correcting for unit and item nonresponse bias in contingent valuation survey data. When sample nonresponse and selection bias go uncorrected, welfare measures may be overestimated or underestimated contributing to potential errors in resource policy and management decisions.
The Effect of Nesting Structure Specification on Welfare Estimation in a Random Utility Model of Recreation Demand: An Application to the Demand for Recreational Fishing
Authors: Hauber A. Brett , Parsons George R. 
Published: March 2003

AbstractNested logit has become common in estimating random utility models of recreation demand. Because welfare analysis is often the objective of estimating these models, it seems natural to ask, what effect does the choice of nesting structure have on the welfare estimates generated by these models? Therefore, we compare the results of nine nesting structures andfindthat the variation in welfare estimates across the models is not large. Our results are contrary to those of Kling and Thomson and Shaw and Ozog. The difference appears to originate with differences in the estimated dissimilarity coefficients in the nested models.
Insect Population Dynamics, Pesticide Use, and Farmworker Health
Authors: Sunding David , Zivin Joshua 
Published: March 2003

AbstractWe address the impacts of regulations designed to reduce pesticide poisoning of farmers and farm laborers. Attention is concentratedon pre‐harvest interval regulations that impose a time interval between pesticide application and harvest. The incidence of poisoning is determined by aggregate pesticide use, worker exposure, and toxicity. A dynamic, stochastic model of insect population growth is developed and used to measure the incentives for pesticide use. Increasing the pre‐harvest interval has an ambiguous effect on the number of harvest worker poisonings. Pesticide taxation unambiguously reduces the number of worker poisonings. Theoretical results are quantified in a case study of mevinphos application on leaf lettuce in California's Salinas Valley.
Optimal Control of Vector‐Virus‐Plant Interactions: The Case of Potato Leafroll Virus Net Necrosis
Authors: Marsh Thomas L. , Huffaker Ray G. , Long Garrell E. 
Published: March 2003

AbstractThis paper introduces a new specification to the economic pest management literature designed to optimally manage vector‐virus‐plant interactions for a single crop. The viral, insect‐vector, and plant‐host stocks are treated as renewable resources and conjunctively controlled in a discrete‐time control framework subject to crop quality standards established in marketing contracts. The result is a conceptual integrated pest management model providing optimal insecticide scheduling and dynamic decision‐making thresholds in a novel economic pest management context. Model results are compared qualitatively with those from previous specifications. The model is applied empirically to control potato leafroll virus net necrosis in commercial potato production.
How to Improve the Management of Renewable Resources: The Case of Canada's Northern Cod Fishery
Authors: Grafton R. Quentin , Sandal Leif K. , Steinshamn Stein Ivar 
Published: March 2003

AbstractThe paper examines howan easy‐to‐apply optimal feedback rule can be used to solve for optimal levels of exploitation of a renewable resource. Using data from Canada's northern cod fishery, the optimal feedback rule is used to derive optimal levels of exploitation for the years 1962–91 under different discount rates, alternative model specifications, and parameter assumptions. The optimal feedback rule indicates that over much of the period the fishery was economically overexploited and, given the stock development that actually took place, a harvesting moratorium should have been instituted three years earlier than when it was introduced. The results show how the use of a simple and flexible optimal rule by managers of renewable resources can generate substantial gains.
Sustainability as Intergenerational Fairness: Efficiency, Uncertainty, and Numerical Methods
Authors: Woodward Richard T. 
Published: March 2003

AbstractThis paper presents an economic model of sustainability defined as intergenerational fairness. Assuming that intergenerational fairness is an obligation of each generation, a recursive optimization problem is obtained. The problem has the advantage that uncertainty can readily be incorporated in the model and it can be solved numerically for a wide range of specifications. The possibility of trade‐offs between efficiency and sustainability are discussed. Under plausible conditions, it is shown that a sustainability obligation is met only if there is the expectation of economic growth.
The Optimal Timing of Evaluation of Genebank Accessions and the Effects of Biotechnology
Authors: Koo Bonwoo , Wright Brian D. 
Published: March 2003

AbstractThe lack of ex ante evaluation of germplasm in genebanks has been the single most prevalent and long‐standing complaint of plant breeders about the management of genebanks. Advances in biotechnology offer the possibility of faster, cheaper and more efficient evaluation methodologies. Will these new technologies favor ex post evaluation, as some expect, or will they lead to more ex ante evaluation? Will they also lead to earlier development of varieties with specific traits in anticipation of demand for them? Will the prospect of further advances in biotechnology favor delay of evaluation and development? This paper addresses these questions in the case of evaluation of germplasm for resistance to a disease.
Searching an Ex Situ Collection of Wheat Genetic Resources
Authors: Gollin Douglas , Smale Melinda , Skovmand Bent 
Published: March 2003

AbstractA theoretical model is developed and applied to the search for disease and pest resistance in ex situ collections of wheat genetic resources, employing actual data on frequency distributions, disease losses, and search costs. Experiments developed from case studies clarify several misperceptions about the value of gene banks and their utilization by breeders. The observation that wheat breeders “use” gene banks rarely does not imply that marginal accessions have low value. High costs of transferring genes with conventional breeding techniques mean that it may be efficient to store certain categories of genetic resources (such as landraces) “unused” for many years.
Constrained Efficient Contracts for Area Yield Crop Insurance
Authors: Vercammen James A. 
Published: March 2003

AbstractWith area yield crop insurance, indemnification occurs when area yield falls below a yield trigger that is chosen by the producer. The maximum value for this yield trigger is generally restricted (e.g., 80% of the long term area average yield). The impact of this trigger constraint on the optimal design of an area yield insurance contract is examined. Within the constrained efficient contract, indemnities consist of both a lump sum payment and a payment that is proportional to the yield shortfall. Because lump sum payments may not be feasible to implement, efficiency‐enhancing modifications to standard contracts are also proposed.
The Role of Farmers' Behavioral Attitudes and Heterogeneity in Futures Contracts Usage
Authors: Pennings Joost M.E. , Leuthold Raymond M. 
Published: March 2003

AbstractThe relationship between farmers' behavioral attitudes and use of futures contracts is examined, taking into account non‐directly observable variables and the heterogeneity of farmers. The relationships are tested on a stratified data sample of 440 farmers. Cluster analysis and covariance structure equation models are used to validate the relationships. Farmers are found not to be homogenous regarding the factors influencing their use of futures. Heterogeneity at the segment level masked important effects at the aggregate level, notably risk attitude. Furthermore, several psychological constructs for farmers related to market orientation, risk exposure, market performance and entrepreneurial behavior play important roles in their use of futures contracts
Financial Structure of Farm Businesses under Imperfect Capital Markets
Authors: Barry Peter J. , Bierlen Ralph W. , Sotomayor Narda L. 
Published: March 2003

AbstractRecent finance studies have considered whether gaps between a firm's costs of internal and external sources of investment funds, arising from capital market imperfections, influence its investment behavior and funding preferences. This study tests the applicability of the pecking order and partial adjustment theories of financial structure to farm businesses by fitting a set of simultaneous financial equations with farm panel data from Illinois. Model results indicate that Illinois farms adjust to long‐run financial targets for equity, debt, and leasing, but that additional financing needs follow a pecking order that is stronger for farms with greater asymmetric information problems
Preference Learning in Consecutive Experimental Auctions
Authors: Shogren Jason F. , List John A. , Hayes Dermot J. 
Published: March 2003

AbstractThis paper explores the origins of the strikingly high price premia paid for new food products in lab valuation exercises. Our experimental design distinguishes between two explanations of this phenomenon: novelty of the experimental experience versus the novelty of the good, i.e., preference learning—bids reflect a person's desire to learn how an unfamiliar good fits into their preference set. Subjects bid in four consecutive experimental auctions for three goods that vary in familiarity, candy bars, mangos, and irradiated meat. Our results suggest that preference learning is the main source of the high premia, and that novelty of the experimental experience does not in itself artificially inflate valuations.
Estimation of Censored Demand Equations from Large Cross‐Section Data
Authors: Perali Federico , Chavas Jean‐Paul 
Published: March 2003

AbstractThe article develops an alternative econometric methodology to estimate a system of censored demand equations using a large cross‐section data from Colombian urban households. The approach preserves the behavioralinformation expressed by zero expenditures and conforms with the requirements imposed by consumer theory in a way consistent with the random utility hypothesis. We motivate the choice of the Tobit modelas a statistical representation of consumer behavior and introduce the methodology by specifying the AIDS model modified according to both a translating and scaling demographic transformation. We propose to estimate each demand equation in unrestricted form using the jackknife technique. We then recover the demand parameters imposing the cross‐equations restrictions by using minimum distance estimation. The empirical results of the censored demand system for specific households of policy relevance are reported.
Estimation of Profit Functions When Profit Is Not Maximum
Authors: Kumbhakar Subal C. 
Published: March 2003

AbstractThis paper deals with derivation and implications of profit functions when profit is not maximum due to the presence of either technical inefficiency or allocative inefficiency, or both. We show that input demand and output supply, elasticities, and returns to scale are, in general, affected by these inefficiencies. We also show that the overall profit efficiency is not necessarily the product of technical and allocative efficiencies, meaning that technical and allocative inefficiencies are not necessarily independent. Estimation techniques are developed for both cross‐sectional and panel data models. Working of the model is illustrated using a panel of 60 salmon farms.
Sequential Adoption of Site‐Specific Technologies and its Implications for Nitrogen Productivity: A Double Selectivity Model
Authors: Khanna Madhu 
Published: March 2003

AbstractThis paper analyzes the sequential decision to adopt two site‐specific technologies, soil testing and variable rate technology, and the impact of adoption on nitrogen productivity. The results indicate that while farm location was a key variable influencing adoption of soil testing, farm size, human capital, and innovativeness of farmers had a significant impact on adoption of variable rate technology in four Midwestern states. A double selectivity model applied to correct for sample selection bias shows that adoption leads to significant gains in nitrogen productivity for farms with below average soil quality but statistically insignificant gains for farms with above average soil quality.
Are Farm Size Distributions Bimodal? Evidence from Kernel Density Estimates of Dairy Farm Size Distributions
Authors: Wolf Christopher A. , Sumner Daniel A. 
Published: March 2003

AbstractOne often hears and sees reference to bimodal distributions of farm size. This notion seems to have become one of the stylized facts about American agriculture. Dairy farm size distributions are prime candidates to exhibit a bimodal size distribution. Older dairy farms tend to be significantly smaller than new dairy farms and there are well known regional size differences. Nonetheless, our analysis of 1989 and 1993 U.S. dairy farm size distributions, using nonparametric density estimation techniques, reveals that U.S. dairy farm size distributions are not bimodal. This result holds across years for herd size, total farm sales, and acres operated.
On the Pitfalls of Multi‐Year Rollover Hedges: The Case of Hedge‐to‐Arrive Contracts
Authors: Lence Sergio H. , Hayenga Marvin L. 
Published: March 2003

AbstractIt is shown that it is theoretically infeasible for multi‐year rollover hedge‐to‐arrive contracts, and for rollover hedges in general, to succeed at locking in high current prices for crops to be harvested one or more years into the future. The study utilizes 107 years of data to present strong empirical evidence that the corn market behaves remarkably similarly to what price theory predicts. Results also confirm that short historical time series are unreliable for predicting rare events. Hence, empirical studies of risk‐management contracts capitalizing on unusual occurrences should use samples sufficiently large to contain a meaningful number of relevant observations.
Valuation of Environmental Goods: Correcting for Bias in Contingent Valuation Studies Based on Willingness‐to‐Accept
Authors: Goldar Bishwanath , Misra Smita 
Published: March 2003

AbstractThe willingness‐to‐accept (WTA) measure of value is often subject to a systematic, large bias, making it unsuitable for use in contingent valuation studies. However, for the valuation of environmental goods, in many cases WTA rather than the willingness‐to‐pay (WTP) is the relevant measure. The paper proposes that, by using a composite‐error model for the estimation of the valuation function, a correction can be made for the bias in reported WTA. To illustrate the proposed methodology, it is applied to the data of the Brookshire‐Coursey (1987) study of alternative tree density in Troutman Park, Fort Collins.