bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of a fuzzy algorithm for pH control in a struvite crystallisation reactor
Authors: Chanona J. , Pastor L. , Borrás L. , Seco A.
Published: July 2006

A struvite crystallisation process is highly dependent on pH. To achieve a high phosphorus recovery as struvite it is important to have an accurate control of pH in the reactor. The high non-linear response of pH value makes manual pH control difficult. Therefore, a software based on fuzzy logic control (FLC) has been developed to maintain the pH at a set value in a stirred reactor to crystallise struvite. The FLC developed has been based on Larsen's inference. In order to confirm the improvement of the pH stability using FLC software, different experiments have been carried out with manual control of the pH value, and with the FLC software. It has been demonstrated that using FLC software allows a precise control of pH with high stability, optimises the process, and minimises the operator intervention.
ASM1 dynamic calibration and long-term validation for an intermittently aerated WWTP
Authors: Marquot A. , Stricker A.-E. , Racault Y.
Published: July 2006

Activated sludge models, and ASM1 in particular, are well recognised and useful mathematical representations of the macroscopic processes involved in the biological degradation of the pollution carried by wastewater. Nevertheless, the use of these models through simulation software requires a careful methodology for their calibration (determination of the model parameters' values) and the validation step (verification with an independent data set). This paper presents the methodology and the results of dynamic calibration and validation tasks as a prior work to a modelling project for defining a reference guideline destined to French designers and operators. To reach these goals, a biological nutrient removal (BNR) wastewater treatment plant (WWTP) with intermittent aeration was selected and monitored for 2 years. Two sets of calibrated parameters are given and discussed. The results of the long-term validation task are presented through a 2-month simulation with lots of operation changes. Finally, it is concluded that, even if calibrating ASM1 with a high degree of confidence with a single set of parameters was not possible, the results of the calibration are sufficient to obtain satisfactory results over long-term dynamic simulation. However, simulating long periods reveals specific calibration issues such as the variation of the nitrification capacity due to external events.
Early Life Stress and Adult Emotional Experience: An International Perspective
Authors: Cohen Ronald A. , Hitsman Brian L. , Paul Robert H. , McCaffery Jeanne , Stroud Laura , Sweet Lawrence , Gunstad John , Niaura Raymond , MaCfarlane Alexander , Bryant Richard A. , Gordon Evian
Published: July 2006

Early life stress (ELS) has been linked to adult psychopathology, though few studies have examined the universality of specific adverse childhood events (ACEs) in healthy adults. We examined the co-occurrence of specific ACEs and their relationship to current emotional distress in an international sample of adults without psychopathology. Participants were 1659 men and women recruited for an international neurocognitive-neuroimaging database from sites in the United States, Australia, England, and the Netherlands. Participants had no current or prior diagnosis of major depression, anxiety, substance abuse, or neurological brain disorder. The occurrence and age on onset of 19 ACEs was assessed by a self-report questionnaire (ELSQ), and current symptoms of stress, depression, and anxiety by the Depression Anxiety Stress Scale (DASS). The relationship of specific ACEs to DASS symptoms was examined. Participants reported relatively high prevalence of ACEs. Only 27.6% of the sample reported no ACEs, while 39.5% reported one or two significant experiences and 32.9% reported more than two ACEs. Rates of most ACEs were quite similar across the three continents. Various ACEs were significantly associated with current DASS severity, particularly ACEs involving emotional abuse, neglect, and family conflict, violence, and breakup. Finding nearly one-third of the sample reported three or more ACEs suggest a high prevalence of ELS in otherwise healthy “normal” adults around the world. Associations between ELS and current emotional distress suggest that these events have functional relevance and deserve further investigation.
Integration of Available and New Technologies to Raise Student Understanding and Engagement
Authors: Souza Joanne , Bingham Paul M.
Published: July 2006

We integrate available and new technologies to strongly enhance student engagement in upper division undergraduate courses on human evolution and history. First, we use peer-mentored discussion groups through the Blackboard system—appropriately scaled, constructed, and incentivized. These allow day-to-day monitoring of student understanding. Second, we use weekly Blackboard e-quizzes directed at important issues or areas of confusion including those revealed by discussion groups. Third, we use a novel digital textbook. This technology provides diverse, sophisticated assets ranging from animations and interactive questions to an extensive glossary hyperlinked to an electronic textbook. The ease of revision of this textbook allows us to react, year to year, to student need and experience. The real power of our approach derives from the extremely strong synergy between these three assets, as we will discuss. We describe successful applications of this model in large (ca. 500) and small (ca 25) classes.
Prescription Drug Abuse Information in D.A.R.E.
Authors: Morris Melissa C. , Cline Rebecca J. Welch , Weiler Robert M. , Broadway S. Camille
Published: July 2006

This investigation was designed to examine prescription drug-related content and learning objectives in Drug Abuse Resistance Education (D.A.R.E.) for upper elementary and middle schools. Specific prescription-drug topics and context associated with content and objectives were coded. The coding system for topics included 126 topics organized within 14 categories. A two-dimensional coding system for context identified Use versus Abuse and Explicit versus Implicit references to prescription drugs. Results indicated that content and objectives found in D.A.R.E. represent a very narrow breadth of prescription drug topics. Moreover, all prescription-drug related content and objectives were presented in an Abuse-Implicit context. Although some educational material in D.A.R.E. modules potentially is related to prescription drugs, none of the content or objectives explicitly identify drugs discussed as prescription drugs. If elementary and middle schools rely on D.A.R.E. modules to teach students about drug abuse, students are likely to be under-informed about prescription drug risks.
An Analysis of Vegetable Contracts
Authors: Jesse Edward V. , Johnson Aaron C.
Published: July 2006

A major portion of the quoted base price variation of green pea and sweet corn contracts used by Wisconsin vegetable processors in 1968 is shown to be associated with variation in other provisions of the contracts. A net price for contracts is derived by adjusting quoted base prices for the effects of nonprice provisions. The adjustment process involves utilization of a dualstage estimating procedure which separately considers the effects on price of quantitative and qualitative provisions. The relative stability of the adjusted price among contracts implies competitive raw product markets for these vegetable crops.
Mechanized Agriculture and Social Welfare: The Case of the Tomato Harvester
Authors: Schmitz Andrew , Seckler David
Published: July 2006

An integrated public‐private approach to mechanical harvesting of tomatoes for canning has sharply reduced producers ' labor requirements. Gross social returns to aggregate research and development expenditures are in the vicinity of 1,000 percent. Even if displaced labor had been compensated for wage loss, net social returns are still highly favorable. Since tomato pickers were unorganized, no compensation was demanded or paid. The analysis indicates a need for policies designed to distribute the benefits and costs of technological change more equitably. Social scientists could properly be concerned with developing institutional means of achieving this goal.
Sensitivity Testing and the Plant Location Problem
Authors: Toft H. I. , Cassidy P. A. , McCarthy W. O.
Published: July 2006

A wide range of models and and solution procedures are now available to the analyst concerned with plant or warehouse location problems. While these produce an optimal solution, no explicit statement is usually made about solution stability. One large group of models concerned with size and siting problems uses the transportation model of linear programming as a solution procedure. This paper presents a method of testing the stability of such solutions. The problem outlined here concerns a plant location study and explicitly examines processing cost variations. However, the sensitivity test used can be applied in general to any cost elements of a transportation problem matrix.
Rural Industrial Growth in the 1960's
Authors: Haren Claude C.
Published: July 2006

This article relies on unpublished data from ongoing research and various special industry and small‐area studies to assay dimensions and explore impacts on rural America of greatly accelerated industrial decentralization in the 1960's. Similar sources identify better highways and local services and facilities, and changing markets, products, and technologies as motivating forces. Brief attention is given to implications for population change, family and community well‐being, and assimilation of poorly educated and unskilled rural people into today's economic mainstream.
A Welfare Analysis of the Voluntary Corn Diversion Program, 1961 to 1966
Authors: Hushak Leroy J.
Published: July 2006

The welfare effects of the com diversion program are analyzed. A three‐sector (corn, other crops, and the rest of the economy) supply‐demand model is developed which incorporates substitution in production and consumption between com and other crops. Using observed data as the restricted market equilibrium and parameters derived from previous research, free market equilibrium is estimated. The net welfare costs and income transfers are computed from the two equilibrium points. In general, the net welfare costs are small and the income transfers are substantial. However, the model is quite sensitive to the parameter values.
Resource Investments, Impact Distribution, and Evaluation Concepts
Authors: Kalter Robert J. , Stevens Thomas H.
Published: July 2006

Governmental decisions on proposed resource investments have always been made within an implicit multidimensional social welfare function framework. Yet the equity consequences of public programs have never been evaluated on an equal basis with their contribution to national economic growth. A model designed to facilitate the measurement of such consequences is specified and applied to a case study. The model can be used in conjunction with different equity classifications, but the test considered the personal income distribution consequences of a proposed water resource investment. The distribution of efficiency benefits and positive intergroup transfers as well as cost and reimbursement questions are considered.
Effects of Split‐Demand and Slaughter‐Capacity Assumptionson Optimal Locations of Cattle Feeding
Authors: Langemeier Larry N. , Finley Robert M.
Published: July 2006

Many studies have concentrated on the optimal location of cattle feeding. Two major limitations of such studies have been (1) reliance on a single demand function for beef and (2) failure to consider existing slaughter capacities. By utilizing separated or split‐demand functions for beef and explicitly accounting for present regional slaughter capacity, quite different patterns of beef feeding emerge. In comparison with actual feedlot locations, the models used showed considerable improvement over most previous models. More importantly, results compare favorably with recent trends in the location of cattle feeding.
Policy Directions for the United States Sugar Program
Authors: Horton Donald C.
Published: July 2006

The legislative basis for the United States sugar program, which involves both a high degree of domestic protectionism and substantial statutory subsidies to sugar producers in selected foreign countries, expires at the end of 1971. The case is presented for reducing domestic protectionism and for financing what remains, as well as any foreign subsidies, through the budget rather than as at present through the domestic price of sugar. A start in those directions is oulined. Also, specific changes in the present sugar program are suggested for consideration in case major reform is not politically feasible in 1971.
Evaluating Supply Control Policies for Frozen Concentrated Orange Juice with an Industrial Dynamics Model
Authors: Raulerson Richard C. , Langham Max R.
Published: July 2006

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. Policies that controlled long‐run supplies by constraining tree plantings appeared to have the most potential for success. Policies designed to control market supplies on a year‐to‐year basis actually encouraged new tree plantings which created long‐run supply problems.
Unit Equivalent Scales for Specific Food Commodities
Authors: Price David W.
Published: July 2006

For many analyses, a per capita specification of the effects of population is not adequate. The per capita specification ignores differences in consumption that are due to differences in age and sex of individuals. A unit equivalent scale can account for these age and sex differences. Unit equivalent scales are estimated for five food commodities and for total food from weekly household expenditure data. The effects of age and sex on expenditures, economies of household size, changes in scales with income level, and changes in the demand for food over time caused by changing age‐sex composition are estimated.
A Practical Computer Method for Pricing Pork Carcasses and Hogs
Authors: Ikerd John E. , Cramer Charles L.
Published: July 2006

Inefficiencies in the production‐marketing system for hogs are due in part to inaccurate derivation of live hog values from expected wholesale cut values. The evaluation method presented in this paper is accurate, objective, and practical when compared to a method used by a progressive firm in the industry. Time series price data and cross sectional carcass data are utilized in a two‐step least squares procedure to estimate carcass value, associated with a given set of wholesale prices, on an individual carcass basis. This method, if used extensively, should lead to improvement in the hog marketing system.
Geographic Flows of Hired Agricultural Labor: 1957–1960
Authors: Gallaway Lowell E.
Published: July 2006

Data obtained from Social Security Administration records are used to examine whether hired agricultural labor moving from one census region to another within the United States is responsive to economic phenomena. The unique feature of the analysis is its access to data describing gross flows of hired agricultural labor among these regions rather than having to rely on observations of net changes in the quantity of such labor. The general conclusion is that hired agricultural workers are responsive to economic phenomena in the directions suggested by formal economic theory but that interregional movement of such workers is greatly hampered by the presence of artificial barriers to mobility.
Measurement of the Impact of Recreation Investments on a Local Economy
Authors: Kalter Robert J. , Lord William B.
Published: July 2006

A from‐to type of interindustry model is formulated and empirically implemented to quantify local economic impacts of a transfer nature arising from outdoor recreation. Direct, indirect, and induced sales, income, and employment impacts are derived and multiplier values are calculated. Relationships among the from‐to model, supplemental studies, and the analysis of regional benefits for governmental investment decisions are discussed.
Nonproducer Cooperative Interests and the Antitrust Laws
Authors: Knutson Ronald D.
Published: July 2006

Cooperatives' ability to enlist the assistance of non‐producer and/or non‐cooperative firms in their marketing efforts has been severely limited by recent Supreme Court decisions. In Case‐Swayne Co. v. Sunkist Growers, Inc., the court held that Sunkist, with nongrower members, was not a Capper‐Volstead cooperative and therefore was not entitled to Capper‐Volstead exemption from prosecution under section 1 of the Sherman Act. Although the case provides a much needed guide for cooperative activity, it did not explicitly define what constitutes a producer. Nor did it provide an indication of the extent to which a cooperative can control or increase its share of the market and still not be held in violation of section 2 of the Sherman Act.
Capital Formation and Growth in the Israeli Cooperative Farm
Authors: Sadan Ezra
Published: July 2006

The Israeli cooperative farm is characterized by a high rate of expansion; the annual rate of growth of the cooperatives' gross product is 11.5 percent. The analysis of the growth pattern of this farm enterprise from 1936 to 1960 suggests that 2 percent of the annual rate of growth of the gross product can be attributed to capital, 1.5 percent to land and labor, 5 percent to the extended utilization of raw materials, and a residual of 3 percent to “technical progress.” A closer examination reveals that a considerable portion of the last is associated with capital formation, probably as a result of technological improvements carried through the flow of gross investments. A smaller portion of the unexplained growth can be attributed to improvements in the “managerial capacity” of the firms under study.
Econometric Analysis of the Agricultural Labor Market
Authors: Tyrchniewicz Edward W. , Schuh G. Edward
Published: July 2006

Previous research on the market for agricultural labor is extended through the use of a simultaneous‐equations model consisting of six equations. The model treats the markets for unpaid family and operator labor, both of which have been slighted in previous work, and takes account of the interdependence among the three components of the agricultural labor force. The demand and supply elasticities were found to differ substantially among the components. Economic implications suggested by the statistical results are analyzed, and the structural models are used to evaluate a number of alternative policies that bear on labor use and labor returns.
Shadow Prices as Member Returns for a Marketing Cooperative
Authors: Hardie Ian W.
Published: July 2006

Many marketing cooperatives handle several types or grades of member‐supplied products. These cooperatives have to determine the returns to be alloted to each product. Helmberger, Hoos, and Nicholls have solved this problem for a cooperative with a single homogeneous product. However, their models do not extent readily to the multiple product case. This article describes how returns can be simultaneously calculated for each member‐supplied product handled by a multiple product marketing cooperative. A linear programming model is first introduced to compute the returns under a set of rather restrictive assumptions. When these assumptions are relaxed, another method of deriving the values is required. Such a method—called the “pooling constraint” method—is presented in the latter part of the article.
Factors Associated with Variation in the Aggregate Average Yield of New Zealand Wheat (1918–1967)
Authors: Guise John W. B.
Published: July 2006

An apparently successful test of a “step function” hypothesis about the effect of technological change in the agricultural sector is reported. The effects of weather and other factors on wheat yields are also analyzed. A notable feature of the research was the lack of significance of an ordinary time trend variable, used as a surrogate for technological change, when a detailed specification of these factors was developed. Overall, 98.6 percent of the variance of the dependent variable in the sample was accounted for by a regression relationship involving seven weather and four non‐weather variables, only one of which related to technological change. The potential value of this relationship for forecasting crop yield is indicated by the fact that the standard error of forecast was substantially less than the standard deviation of errors for the present system of pre‐harvest yield estimation.
Effects of Federal Income Taxes on Cattle‐Ranch Prices*
Authors: Martin William E. , Gatz Jimmie R.
Published: July 2006

Past studies have indicated that returns from beef production are not enough to justify economically the current prices of cattle ranches. It has been hypothesized that federal income taxes influence current ranch prices. Standard economic budgets are converted into tax budgets for use in testing this hypothesis. The procedure and assumptions involved in the analysis are briefly listed. Although tax savings can be substantial under specific assumptions, the general effect of ranches as tax shelters cannot be large enough to affect greatly the general level of ranch prices.
Combining Cross‐Section and Time‐Series Information on Demand Relationships for Substitute Goods
Authors: Holmes R. A.
Published: July 2006

This study deals with the problem of pooling cross‐section and time‐series results in the estimation of demand functions when the appropriate endogenous variable differs in the two analyses. An iterative estimation procedure which incorporates a necessary distinction between quantity and quality elasticities of demand is developed and tested. This procedure addresses the estimation problems arising from differences between the cross‐section and time‐series models and data, and provides a partial test of the model specification.
Effects of Nonprice Variables upon Participation in Water‐oriented Outdoor Recreation
Authors: Gillespie Glenn A. , Brewer Durward
Published: July 2006

The increasing proportion of the population which lives and works in metropolitan areas is a primary factor in the growing demand for recreation. Recreation research concerning the allocation of land and water to meet more fully the demand for water‐oriented outdoor recreation is of increasing importance as population increases. The model developed here allows appraisal of nonprice information needed by private and government decision makers in planning for recreational uses of land and water. It permits projections of recreation participation for a population of a metropolitan area by utilizing changes in the socioeconomic composition of the population as well as its size.
Efficient Equalization Funds for Farm Prices*
Authors: Candler Wilfred , McArthur Alastair
Published: July 2006

The objective of an equalization fund is to “accept” a series of market prices over a period of time and transform these into equalized prices to farmers, so that the equalized prices have a lower variance than the original market prices. An arrangement which minimizes the variance of equalized payments for a given variance of the equalization fund is said to be efficient. The derivation of efficient funds is considered for the case where prices are independent and autocorrelated (for one year). Quantity supplied is taken to be independent of price, but price is a function of quantity. It is shown that the “instinctive” suggestion of an equalized price calculated as a moving average, with equal weights, of previous prices, is appropriate only if fluctuations in the equalization fund are of no interest.
Economic Considerations in Response Research
Authors: Anderson J. R. , Dillon John L.
Published: July 2006

The general neglect of economic considerations in response research is noted. Following the listing of several factors which influence investment in response research, a framework is developed in which knowledge of a process is viewed in terms of the expected value and variance of profits. A Bayesian scheme for incorporating additional information in posterior analysis is outlined. Worth of additional information is judged in terms of utility. The scheme is used to show how the value of obtaining additional information can be ascertained ex ante in preposterior analysis by way of a Monte‐Carlo approach. Both posterior and preposterior analyses are illustrated through a soybean‐fertilizer process. In this empirical example, the effects of using different experimental designs of varying size are examined.
Shifts in Entrepreneurial Functions in Agriculture
Authors: Harris Marshall
Published: July 2006

Substantial elements of entrepreneurship in agriculture are being shifted to off‐farm firms and government agencies. These shifts involve public programs that control land use and guide its development and that take private land for public purpose. In the private sector, they include substitution of corporate enterprise for family farming, restrictions on freedom of action under credit arrangements, control over tenant‐operated farms, direction of management under vertical coordination contracts, and control of farmer cooperatives and bargaining associations over buying and selling. In the future, family farming may be under pressure to meet technological requirements, and corporation farming may offer competition. In the absence of a massive support program, the family farmer may continue to shift elements of entrepreneurship to off‐farm firms. An important question is: What is happening to farmer entrepreneurship under the impact of modern technology and urbanization?
Sources of Agricultural Productivity Gap Among Selected Countries
Authors: Hayami Yujiro
Published: July 2006

This study explores the causes of enormous agricultural productivity differences now existing among the developed and less developed countries. Factors are identified that determine the productivity gap, and their influences are gauged on the 1957–62 national aggregate data of 38 nations. Aggregate production functions are estimated on the cross‐country data; and, with the estimates of production elasticities, the productivity differences between India and United States and between India and Japan are accounted for by conventional inputs (labor, land, fertilizer and machinery) and nonconventional inputs (education and research). The measured contributions of respective factors to the productivity differences provide a guideline for allocating development efforts in the less developed countries.
Predicting Aggregate Milk Production: An Empirical Study
Authors: Zepp Glenn A. , McAlexander Robert H.
Published: July 2006

There is a need for predictive and aggregate output response models suitable for answering questions about short‐term changes in agricultural output. In this study, short‐term milk output projections for Southeast Pennsylvania between 1961 and 1965 were derived with a linear programming, a recursive programming, and a regression model. The predictiveness of each model is evaluated by comparing its estimate of aggregate milk production with reported output for target years. Differences are expressed as percentage error from reported production.
The Integrated Use of Ground and Surface Water in Irrigation Project Planning
Authors: Rogers Peter , Smith Douglas V.
Published: July 2006

The model we propose determines water balances for a project area and emphasizes interactions of a surface water‐groundwater system within the economic context of irrigation management. The program selects the tubewell, canal and surface drainage capacities, the project size, and the cropping pattern. Operation of the system is assumed to proceed subject to certain constraints on continuity at the river; capacity of the canals, tubewells, and drainage channels; mining of groundwater; crop water requirements; availability of land of different soil types; and permissible cropping patterns. A detailed irrigation planning example is presented.
Spatial, Temporal and Product‐Use Allocation of Milk in an Imperfectly Competitive Dairy Industry
Authors: Kottke Marvin
Published: July 2006

A multistage allocation model is designed to deal with two real‐world conditions that are bothersome in the application of spatial equilibrium models to the dairy industry. The multidimensional nature of milk allocation and the diversity of competitive structure within the industry must be faced to obtain realistic results. A set of recursive relations incorporating linear and quadratic programming formulations is used to handle the temporal and product‐use dimensions in addition to the spatial dimension. An application of the model to the New England dairy industry traces price, production, and consumption patterns over time.
A Development Planning Model for Technological Change in Agriculture
Authors: Goodwin Joseph B. , Blase Melvin G. , Colyer Dale
Published: July 2006

This article examines a model for (1) coordinating activities in the development process and (2) inter‐temporally allocating resources required by the process. Network analysis (PERT) and recursive programming are integrated in the model, which is applied to data for a district in India. The findings provide insights into the sporadic nature of economic development and differential marginal value productivities of limiting resources over time. The integrated planning technique, resulting from the methodological study, appears to be especially useful for spotting potential bottlenecks sufficiently early to initiate action for eliminating them, thereby facilitating the development process.
“Modernization Effect” upon Exports of Agricultural Produce: South Korea
Authors: Cho Jae H.
Published: July 2006

The “demand deficiency” hypothesis, which has been used to explain the post‐1945 “export lag” of agricultural produce from non‐industrial areas, is irrelevant to the “export lag” of foodstuffs from overpopulated countries. South Korean experiences strongly suggest that a relatively high marginal propensity to consume food, combined with a relatively high price inelasticity of demand for food, makes the income redistribution consequent upon modernization a forceful factor in determining the export pattern of an underdeveloped country. Misleading export projections of foodstuffs during early stages of economic development result if income distribution effects are not taken into account.
Tariffs, Nontariff Distortions, and Effective Protection in U. S. Agriculture
Authors: Wipf Larry J.
Published: July 2006

This paper extends the effective‐protection concept to include tariff and nontariff trade distortions and also the entire structure of domestic farm policy measures. Nominal and effective rates of protection are then presented for disaggregated agricultural production and processing industries for the years 1958, 1963, and 1968. The estimates reveal that nontariff measures give rise to extremely high effective protection rates in certain agricultural sectors; in others, tariff and nontariff measures affecting intermediate inputs have important taxation effects. The analysis also indicates that agricultural policy changes have substantially altered the rates of protection accorded certain agricultural sectors.
A Supply Response Model for Perennial Crops
Authors: French Ben C. , Matthews Jim L.
Published: July 2006

The production of perennial crops involves planting, removal, yield, and time dimensions not similarly encountered in annual crops. A model is developed to provide a structural base for estimating response relationships that encompass these dimensions. The model rests on assumptions of rational producer behavior which takes account of possible actions of other producers and of the aggregate effect of these actions on total production and profits. Because important data series often are not available, modifications of the basic model are suggested to facilitate estimation within a more restricted empirical framework. The model is illustrated by an application to asparagus, a perennial vegetable crop.
Effectiveness of Pricing in an Indian Wheat Market: A Case Study of Khanna, Punjab
Authors: Cummings Ralph W.
Published: July 2006

An important issue in food grain marketing in India concerns the effectiveness of competition, but there is little empirical research on which to evaluate the issue. This article analyzes pricing effectiveness in one private wholesale wheat market in north India by comparing average seasonal and spatial price differences with estimated storage and transport costs. The comparisons indicate that correspondence between average price movements and average cost differences was reasonably close.
Statistical Analysis of Identities in Random Variables
Authors: Burt Oscar R. , Finley Robert M.
Published: July 2006

A random variable of economic interest is sometimes an identity function of two or more separate variables; for example, crop income per acre is the product of price and yield. This article presents a method for partitioning the variance of such a random variable into components that can be associated with the separate random variables in the identity and interactions among them. Under some statistical assumptions on the variables involved, the converse of the partitioning procedure is useful for deriving the variance of a random variable from the moments of the separate variables of the identity.
A Policy for Public Investments in Natural Resources
Authors: Cotner Melvin L.
Published: July 2006

Both pessmistic and optimistic views exist concerning the effects of resource scarcity on social welfare. Early classical doctrines that assume a fixed state of technology are the theoretical underpinning for the pessimistic view. But a new concept of resources has evolved in recent years that suggests the optimistic view. Resources can be created through science and technology. Existing resources can be made more productive and new resources can be created. Economic growth is a function of adequate resources to absorb investments. Resource creation and the improved use of existing resources, then, are key elements of a policy for public investments in natural resources. From a policy standpoint, public resource improvement investments must be compared with the social benefit streams created. Furthermore, these investments must be compared with alternative investment opportunities, such as extension‐education programs, which would improve the use of existing resources.
Econometric Study of Monthly Consumption Expenditures in Rural Uttar Pradesh
Authors: Tendulkar Suresh D.
Published: July 2006

This study presents some evidence of monthly consumption functions in the rural areas of the North Indian State of Uttar Pradesh. Since this region constitutes one of the largest and least monetized in India, attention is specifically focused on the cash and kind (or non‐cash) components of (a) expenditure on food articles and (b) total consumption expenditure. Dynamic demand functions of a stock‐flow variety are obtained for these broad groups. It is shown that cash outlays act as an inventory‐adjustment mechanism whereas non‐cash expenditure indicates a habit formation process. This behavioral difference of rural households with respect to cash and non‐cash components of consumption expenditure has not yet been demonstrated and is regarded as one of the major results of this paper. With the use of a stock‐flow adjustment system, numerical estimates of the instantaneous and steady‐state equilibrium elasticities are derived with respect to total expenditure (a proxy for income) and prices.
Reliability of Supply Equations Derived from Production Functions
Authors: Wipf Larry J. , Bawden D. Lee
Published: July 2006

This paper examines the reliability of supply functions derived from empirically estimated production functions. Firm‐level supply equations are derived from production functions for selected agricultural commodities, and these are used to predict firm output and to estimate supply elasticities. The results are then compared with actual or expected output and with supply elasticities estimated directly by regression analysis of time series data. Output predictions ranged from slight under‐estimates to extreme over‐estimates of actual output, with the latter being most prevalent. The derived supply elasticities were generally higher than those obtained by direct regression analysis.
Identification of sources of Salmonella organisms in a veterinary teaching hospital and evaluation of the effects of disinfectants on detection of Salmonella organisms on surface materials
Authors: Ewart Susan L. , Schott II Harold C. , Robison Rachel L. , Dwyer Roberta M. , Eberhart Susan W. , Walker Robert D.
Published: July 2006

Objective—To determine sources ofSalmonellaorganisms in a veterinary teaching hospital, compare bacterial culture with polymerase chain reaction (PCR) testing for detection ofSalmonellaorganisms in environmental samples, and evaluate the effects of various disinfectants on detection ofSalmonellaorganisms on surface materials.

Design—Prospective study.

Sample Population—Fecal samples from 638 hospitalized horses and 783 environmental samples.

Procedure—Standard bacterial culture techniques were used; the PCR test amplified a segment of theSalmonellaDNA. Five disinfectants were mixed withSalmonellasuspensions, and bacterial culture was performed. Swab samples were collected from 7 surface materials after inoculation of the surfaces withSalmonellaTyphimurium, with or without addition of a disinfectant, and submitted for bacterial culture and PCR testing.

Results—Salmonellaorganisms were detected in fecal samples from 35 (5.5%) horses. For environmental samples, the proportion of positive bacterial culture results (1/783) was significantly less than the proportion of positive PCR test results (110/783), probably because of detection of nonviable DNA by the PCR test. Detection ofSalmonellaorganisms varied with the surface material tested, the method of detection (bacterial culture vs PCR testing), and the presence and type of disinfectant.

Conclusions and Clinical Relevance—Results of the present study suggested thatSalmonellaorganisms can be isolated from feces of hospitalized horses and a variety of environmental surfaces in a large animal hospital. Although recovery ofSalmonellaorganisms was affected by surface material and disinfectant, bleach was the most effective disinfectant on the largest number of surfaces tested. (J Am Vet Med Assoc2001;218:1145–1151)
Evaluation of selected-protein-source diets for management of dogs with adverse reactions to foods
Authors: Leistra Mieke H. G. , Markwell Peter J. , Willemse Ton
Published: July 2006

Objective—To evaluate 3 commercially available selected-protein-source diets as maintenance diets in dogs with pruritus caused by adverse food reactions.

Design—Randomized crossover trial.

Animals—40 dogs > 6 months of age with pruritus caused by adverse reactions to foods.

Procedure—Diagnosis was confirmed by use of diet elimination and provocation studies. Subsequently, dogs were fed 3 commercial diets for 3 weeks each in a randomized, blinded, crossover trial. Dogs were evaluated for pruritus, vomiting, diarrhea, and flatulence.

Results—Pruritus recurred in 52.5% of dogs fed a chicken-rice diet, 47.5% of dogs fed a catfish-rice diet, and 85% of dogs fed a venison-rice diet. Overall, 95% of the dogs could be managed successfully with at least 1 of the 3 diets.

Conclusions and Clinical Relevance—Results indicated that commercially available limited-allergen diets with selected protein sources may be appropriate for long-term management of pruritus caused by adverse food reactions. Testing of various protein sources is usually required. (J Am Vet Med Assoc2001;219:1411–1414)
Antimicrobial susceptibility patterns of Salmonella isolates from cattle in feedlots
Authors: Dargatz David A. , Fedorka-Cray Paula J. , Ladely Scott R. , Ferris Kathleen E. , Green Alice L. , Headrick Marcia L.
Published: July 2006

Objective—To evaluate the antimicrobial susceptibility
patterns of Salmonella isolates from feedlot cattle.

Design—Cross-sectional study.

Sample Population—263 Salmonella isolates.

Procedures—Fecal samples were collected from the
floor of 2 pens in each of 100 feedlots. Two hundred
eighty Salmonella isolates were recovered after bacteriologic
culture from 38 pens. Of these, 263 isolates
were available for antimicrobial susceptibility testing
to 16 antimicrobials, using microbroth dilution breakpoint
plates.

Results—Less than 5% of isolates were resistant to
any of the antimicrobials tested, with the exception of
sulfamethoxazole (15; 5.7%) and tetracycline (61;
23.2%). Most isolates (197; 74.9%) were susceptible
to all antimicrobials tested, whereas 18 (6.8%) were
resistant to 2 or more antimicrobials. The percentage
of isolates with resistance to any antimicrobial varied
by serotype. The percentage of isolates resistant to
various antimicrobials was not related to concurrent
use of antimicrobials in the feed.

Conclusions and Clinical Relevance—With the
exception of tetracycline and sulfamethoxazole, resistance
of Salmonella isolates to any of the antimicrobials
was uncommon. Most isolates were susceptible
to all antimicrobials tested. Antimicrobial resistance
was not related to the presence of antimicrobials in
the ration being fed at the time of sample collection.
(J Am Vet Med Assoc 2002;221:268–272)
Comparison of polymerase chain reaction assay, bacteriologic culture, and serologic testing in assessment of prevalence of urinary shedding of leptospires in dogs
Authors: Harkin Kenneth R. , Roshto Yvette M. , Sullivan Jennifer T. , Purvis Tanya J. , Chengappa M. M.
Published: July 2006

Objective—To compare results of polymerase chain reaction (PCR) testing of urine samples, serologic testing, and bacteriologic culture of urine to determine prevalence of urinary shedding of leptospires in dogs.

Design—Serial case study.

Animals—500 dogs evaluated serially without regard to health status.

Procedure—Urine samples were examined via PCR assay and bacteriologic culture for leptospires. Blood samples were analyzed for antibodies against serovars canicola, bratislava, pomona, icterohemorrhagiae, grippotyphosa, and hardjo.

Results—Titers ≥ 1:100 against at least 1 serovar were detected in 104 (20.8%) dogs, and titers ≥ 1:400 were detected in 41 (8.2%) dogs. High titers were detected most commonly to serovar grippotyphosa, followed by icterohemorrhagiae, canicola, pomona, bratislava, and hardjo. High titers to > 1 serovar were detected in 14 dogs. A positive PCR assay result was obtained in 41 (8.2%) dogs, only 9 of which had a titer ≥ 1:100. Leptospires were not cultured from the urine of any dog. Only 4 dogs had clinical leptospirosis. Overall disease prevalence was 0.8% for the 6-month evaluation period. Compared with PCR assay, serologic testing for predicting shedding had a sensitivity of 22%, specificity of 79%, positive predictive value of 9%, and negative predictive value of 92%.

Conclusions and Clinical Relevance—Irrespective of health status, 8.2% of dogs were shedding pathogenic leptospires. Serologic testing was a poor predictor of urinary shedding. Clinically normal dogs that shed leptospires may pose a zoonotic risk to their owners. (J Am Vet Med Assoc2003;222:1230–1233)
Association between lymph node size and metastasis in dogs with oral malignant melanoma: 100 cases (1987–2001)
Authors: Williams Laurel E. , Packer Rebecca A.
Published: July 2006

Objective—To determine the association between lymph node size and metastasis and to assess measurement of lymph node size as an accurate and reliable means of tumor staging in dogs with oral malignant melanoma.

Design—Retrospective study.

Animals—100 dogs with histologically confirmed oral malignant melanoma.

Procedure—Clinical records for dogs with oral malignant melanoma were reviewed. Data regarding size and results of cytologic or histologic examination of lymph nodes were evaluated. The association between lymph node size and metastasis was determined.

Results—Forty-seven (47%) dogs, of which 23 (49%) had enlarged mandibular lymph nodes, had no cytologic or histologic evidence of metastasis. Of 53 (53%) dogs with cytologic or histologic evidence of mandibular lymph node metastasis, 37 (70%) had enlarged mandibular lymph nodes, and 16 (30%) had mandibular lymph nodes of normal size. Overall, 16 of the 40 (40%) dogs with normal-sized lymph nodes had microscopic evidence of metastatic disease. Sensitivity and specificity of lymph node size as a predictor of metastasis were 70 and 51%, respectively, and the positive and negative predictive values were 62 and 60%, respectively.

Conclusions and Clinical Relevance—Although a significant relationship was identified between lymph node size and metastasis to the lymph node, this association did not appear strong enough to be clinically relevant. Results suggest that lymph node size alone is insufficient for accurate clinical staging of oral malignant melanoma in dogs; cytologic or histologic examination of regional lymph nodes should routinely be performed, regardless of size of those nodes. (J Am Vet Med Assoc2003;222:1234–1236)
Use of a commercially available culture system for diagnosis of Tritrichomonas foetus infection in cats
Authors: Gookin Jody L. , Foster Derek M. , Poore Matthew F. , Stebbins Marty E. , Levy Michael G.
Published: July 2006

Objective—To evaluate the efficacy of and optimize a commercially available culture system for sensitive and specific in-clinic culture ofTritrichomonas foetusfrom cat feces.

Design—Prospective study.

Sample Population—Samples of freshly voided feces from 117 purebred cats and pure cultures ofT foetusobtained from a cat with chronic diarrhea.

Procedure—Optimal conditions for use of the culture system, such as quantity of fecal inoculum (0.025 to 0.2 g) and cultivation temperature (25 or 37°C [98.6 or 77.0°F]), were determined. Specificity of the system was examined by attempted culture ofGiardia lambliaandPentatrichomonas hominis. Sensitivity of the system to detectT foetuswas determined by inoculation of culture system pouches with serially dilutedT foetussuspensions with and without feces.

Results—Detection limit of the culture system was 1 and 1,000T foetusorganisms without and with feces from cats, respectively. Optimal fecal inoculum was < 0.1 g of feces. At 37°C, cultures yielded positive results in 24 hours; organisms remained viable for 1 to 6 days, and bacterial overgrowth was common. At 25°C, cultures yielded positive results in 1 to 11 days; organisms were long-lived, and bacterial overgrowth was uncommon. NeitherG lambliaorP hominissurvived in the culture system.

Conclusions and Clinical Relevance—The culture system was sensitive and specific for culture ofT foetusin feces of cats. Performance was optimal when test kits were inoculated with ≤ 0.1 g of freshly voided feces and cultured at 25°C. (J Am Vet Med Assoc2003;222:1376–1379)