bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative Risk Assessment of Rabies Entering Great Britain from North America via Cats and Dogs
Authors: Jones Rowena D. , Kelly Louise , Fooks Anthony R. , Wooldridge Marion
Published: July 2005

Great Britain has been rabies‐free since 1922, which is often considered to be in part due to the strict laws requiring that imported cats and dogs be vaccinated and quarantined for 6 months immediately on entry into the country. Except for two isolated incidents, this quarantine policy has contributed to ensuring that Great Britain has remained free of rabies. In 2000, amendments to the UK quarantine laws were made and the Pet Travel Scheme (PETS) was launched for companion animals traveling from European Union countries and rabies‐free islands. Since its introduction, it has been proposed that other countries including North America should be included within the UK scheme. A quantitative risk assessment was developed to assist in the policy decision to amend the long‐standing quarantine laws for dogs and cats from North America. It was determined that the risk of rabies entry is very low and is dependent on the level of compliance (i.e., legally conforming to all of the required regulations) with PETS and the number of pets imported. Assuming 100% compliance with PETS and the current level of importation of cats and dogs from North America, the annual probability of importing rabies is lower for animals traveling via PETS (7.22 × 10−6, 95th percentile) than quarantine (1.01 × 10−5, 95th percentile). These results, and other scientific evidence, directly informed the decision to expand the PETS scheme to North America as of December 2002.
Hazardous Factories: Nigerian Evidence
Authors: Oloyede Olajide
Published: July 2005

The past 15 years have seen an increasing governmental and corporate concern for the environment worldwide. For governments, information about the environmental performance of the industrial sector is required to inform macro‐level decisions about environmental targets such as those required to meet UN directives. However, in many African, Asian, and Latin American countries, researching and reporting company environmental performance is limited. This article serves as a contribution to filling the gap by presenting evidence of physical and chemical risk in Nigerian factories. One hundred and three factories with a total of 5,021 workers were studied. One hundred and twenty physical and chemical hazards were identified and the result shows a high number of workers exposed to such hazards. The study also reveals that workers' awareness level of chemical hazards was high. Yet the danger was perceived in behavioral terms, especially by manufacturing firms, which tend to see environmental investment in an increasingly global economy as detrimental to profitability.
Assessing Uncertainty in Simulation‐Based Maritime Risk Assessment
Authors: Merrick Jason R. W. , Van Dorp J. Rene , Dinesh Varun
Published: July 2005

Recent work in the assessment of risk in maritime transportation systems has used simulation‐based probabilistic risk assessment techniques. In the Prince William Sound and Washington State Ferries risk assessments, the studies’ recommendations were backed up by estimates of their impact made using such techniques and all recommendations were implemented. However, the level of uncertainty about these estimates was not available, leaving the decisionmakers unsure whether the evidence was sufficient to assess specific risks and benefits. The first step toward assessing the impact of uncertainty in maritime risk assessments is to model the uncertainty in the simulation models used. In this article, a study of the impact of proposed ferry service expansions in San Francisco Bay is used as a case study to demonstrate the use of Bayesian simulation techniques to propagate uncertainty throughout the analysis. The conclusions drawn in the original study are shown, in this case, to be robust to the inherent uncertainties. The main intellectual merit of this work is the development of Bayesian simulation technique to model uncertainty in the assessment of maritime risk. However, Bayesian simulations have been implemented only as theoretical demonstrations. Their use in a large, complex system may be considered state of the art in the field of computational sciences.
The 1991 Cholera Epidemic in Peru: Not a Case of Precaution Gone Awry
Authors: Tickner Joel , Gouveia‐Vigeant Tami
Published: July 2005

The precautionary principle calls on decisionmakers to take preventive action in light of evidence indicating that there is a potential for harm to public health and the environment, even though the nature and magnitude of harm are not fully understood scientifically. Critics of the precautionary principle frequently argue that unbridled application of the principle leads to unintended damage to health and ecosystems (risk tradeoffs) and that precautious decision making leaves us vulnerable to "false‐positive" risks that divert resources away from “real risks.” The 1991 cholera epidemic in Peru is often cited as an example of these pitfalls of the precautionary principle. It has been mistakenly argued that application of the precautionary principle caused decisionmakers to stop chlorinating the water supply due to the risks of disinfection byproducts (DBPs), resulting in the epidemic. Through analyses of investigations conducted in the cities of Iquitos and Trujillo, Peru, literature review, and interviews with leading Peruvian infectious disease researchers, we determined that the epidemic was caused by a much more complex set of circumstances, including poor sanitation conditions, poor separation of water and waste streams, and inadequate water treatment and distribution systems. The evidence indicates that no decision was made to stop chlorinating on the basis of DBP concerns and that concerns raised about DBPs masked more important factors limiting expansion of chlorination. In fact, outside of Peru's capital Lima, chlorination of drinking water supplies at the time of the epidemic was limited at best. We conclude that the Peruvian cholera epidemic was not caused by a failure of precaution but rather by an inadequate public health infrastructure unable to control a known risk: that of microbial contamination of water supplies.
Improving Food Safety in the Domestic Environment: The Need for a Transdisciplinary Approach
Authors: Fischer Arnout R. H. , De Jong Aarieke E. I. , De Jonge Rob , Frewer Lynn J. , Nauta Maarten J.
Published: July 2005

Microbial food safety has been the focus of research across various disciplines within the risk analysis community. Natural scientists involved in food microbiology and related disciplines work on the identification of health hazards, and the detection of pathogenic microorganisms. To perform risk assessment, research activities are increasingly focused on the quantification of microbial contamination of food products at various stages in the food chain, and modeling the impact of this contamination on human health. Social scientists conduct research into how consumers perceive food risks, and how best to develop effective risk communication with consumers in order to improve public health through improved food handling practices. The two approaches converge at the end of the food chain, where the activities regarding food preparation and food consumption are considered. Both natural and social sciences may benefit from input and expertise from the perspective of the alternative discipline, although, to date, the integration of social and natural sciences has been somewhat limited. This article therefore explores the potential of a transdisciplinary approach to food risk analysis in terms of delivering additional improvements to public health. Developing knowledge arising from research in both the natural and social sciences, we present a novel framework involving the integration of the two approaches that might provide the most effective way to improve the consumer health associated with food‐borne illness.
Transmissible Spongiform Encephalopathy Risk Assessment: The UK experience
Authors: Grist Eric P. M.
Published: July 2005

Transmissible spongiform encephalopathy (TSE) risk assessments undertaken in the United Kingdom have mainly had the objective of determining the risks posed to humans from exposure to the causal agents associated with bovine spongiform encephalopathy (BSE) and variant Creutzfeld‐Jakob disease (vCJD). In this article, I examine 19 of these risk assessments published to date and consider how their results might be influenced by underlying model assumptions and methodology. Three separate aspects common to all the assessments are infective load estimation, exposure pathway identification, and risk estimation. These are each discussed in detail.
Quantitative Analysis of Variability and Uncertainty with Known Measurement Error: Methodology and Case Study
Authors: Zheng Junyu , Frey H. Christopher
Published: July 2005

The appearance of measurement error in exposure and risk factor data potentially affects any inferences regarding variability and uncertainty because the distribution representing the observed data set deviates from the distribution that represents an error‐free data set. A methodology for improving the characterization of variability and uncertainty with known measurement errors in data is demonstrated in this article based on an observed data set, known measurement error, and a measurement‐error model. A practical method for constructing an error‐free data set is presented and a numerical method based upon bootstrap pairs, incorporating two‐dimensional Monte Carlo simulation, is introduced to address uncertainty arising from measurement error in selected statistics. When measurement error is a large source of uncertainty, substantial differences between the distribution representing variability of the observed data set and the distribution representing variability of the error‐free data set will occur. Furthermore, the shape and range of the probability bands for uncertainty differ between the observed and error‐free data set. Failure to separately characterize contributions from random sampling error and measurement error will lead to bias in the variability and uncertainty estimates. However, a key finding is that total uncertainty in mean can be properly quantified even if measurement and random sampling errors cannot be separated. An empirical case study is used to illustrate the application of the methodology.
An Ecological Risk Assessment of Nonnative Boas and Pythons as Potentially Invasive Species in the United States
Authors: Reed Robert N.
Published: July 2005

The growing international trade in live wildlife has the potential to result in continuing establishment of nonnative animal populations in the United States. Snakes may pose particularly high risks as potentially invasive species, as exemplified by the decimation of Guam's vertebrate fauna by the accidentally introduced brown tree snake. Herein, ecological and commercial predictors of the likelihood of establishment of invasive populations were used to model risk associated with legal commercial imports of 23 species of boas, pythons, and relatives into the United States during the period 1989–2000. Data on ecological variables were collected from multiple sources, while data on commercial variables were collated from import records maintained by the U.S. Fish and Wildlife Service. Results of the risk‐assessment models indicate that species including boa constrictors (Boa constrictor), ball pythons (Python regius), and reticulated pythons (P. reticulatus) may pose particularly high risks as potentially invasive species. Recommendations for reducing risk of establishment of invasive populations of snakes and/or pathogens include temporary quarantine of imports to increase detection rates of nonnative pathogens, increasing research attention to reptile pathogens, reducing the risk that nonnative snakes will reach certain areas with high numbers of federally listed species (such as the Florida Keys), and attempting to better educate individuals purchasing reptiles.
Duration Adjustment of Acute Exposure Guideline Level Values for Trichloroethylene Using a Physiologically‐Based Pharmacokinetic Model
Authors: Boyes William K. , Evans Marina V. , Eklund Christopher , Janssen Paul , Simmons Jane Ellen
Published: July 2005

Acute Exposure Guideline Level (AEGL) recommendations are developed for 10‐minute, 30‐minute, 1‐hour, 4‐hours, and 8‐hours exposure durations and are designated for three levels of severity: AEGL‐1 represents concentrations above which acute exposures may cause noticeable discomfort including irritation; AEGL‐2 represents concentrations above which acute exposure may cause irreversible health effects or impaired ability to escape; and AEGL‐3 represents concentrations above which exposure may cause life‐threatening health effects or death. The default procedure for setting AEGL values across durations when applicable data are unavailable involves estimation based on Haber's rule, which has an underlying assumption that cumulative exposure is the determinant of toxicity. For acute exposure to trichloroethylene (TCE), however, experimental data indicate that momentary tissue concentration, and not the cumulative amount of exposure, is important. We employed an alternative approach to duration adjustments in which a physiologically‐based pharmacokinetic (PBPK) model was used to predict the arterial blood concentrations [TCEa] associated with adverse outcomes appropriate for AEGL–1, –2, or –3‐level effects. The PBPK model was then used to estimate the atmospheric concentration that produces equivalent [TCEa] at each of the AEGL‐specific exposure durations. This approach yielded [TCEa] values of 4.89 mg/l for AEGL‐1, 18.7 mg/l for AEGL‐2, and 310 mg/l for AEGL‐3. Duration adjustments based on equivalent target tissue doses should provide similar degrees of toxicity protection at different exposure durations.
Public Perceptions of Risk to Forest Biodiversity†
Authors: McFarlane Bonita L.
Published: July 2005

This study examines the perceived risks to forest biodiversity and perceived effectiveness of biodiversity conservation strategies among the general public. It tests the hypotheses that perceived risk to forest biodiversity is influenced by cognitive factors (value orientation and knowledge) and social‐cultural factors (such as gender and environmental membership) and that risk perceptions influence other cognitive constructs such as support for natural resource policy and management. Data were collected from a sample of the general public (n= 596) in British Columbia, Canada by mail survey in 2001. Results show that insects and disease were perceived as the greatest risk. Educating the public and industry about biodiversity issues was perceived as a more effective conservation strategy than restricting human uses of the forest. Value orientation was a better predictor of perceptions of risk and perceived effectiveness of conservation strategies than knowledge indicators or social‐cultural variables. Examining the indirect effects of social‐cultural variables, however, revealed that value orientation may amplify the effect of these variables and suggests that alternative paths of influence should be included. Perceived risk showed an inconsistent association with perceived effectiveness of conservation strategies.
The Greater Ability of Graphical Versus Numerical Displays to Increase Risk Avoidance Involves a Common Mechanism
Authors: Schirillo James A. , Stone Eric R.
Published: July 2005

By displaying a risk reduction of 50% graphically rather than numerically, Stone, Yates, and Parker significantly increased professed risk‐avoidant behavior. The current experiments replicated this effect at various risk ratios. Specifically, participants were willing to spend more money to reduce a risk when the risk information was displayed by asterisks rather than by numbers for risk‐reduction ratios ranging from 3% to 97%. Transforming the amount participants were willing to spend to logarithms significantly improved a linear fit to the data, suggesting that participants convert this variable within the decision‐making process. Moreover, a log‐linear model affords an exceptional fit to both the graphical and numerical data, suggesting that a graphical presentation elicits the same decision‐making mechanism as does the numerical display. In addition, the data also suggest that each person removed from harm is weighted more by some additional factor in the graphical compared to the numerical presentations.
What's Time Got to Do with It? Inattention to Duration in Interpretation of Survival Graphs
Authors: Zikmund‐Fisher Brian J. , Fagerlin Angela , Ubel Peter A.
Published: July 2005

Reports of randomized clinical trials often use survival curves to summarize clinical outcomes over time and graphically demonstrate evidence of treatment effectiveness. Survival curves can also be used in patient communications to display how health risks accumulate over time. In a randomized survey experiment, administered online, we tested whether people viewing survival curves appropriately adjust their risk perceptions to account for the duration shown. Internet users (N= 864) were recruited from a demographically balanced U.S. panel. Participants read about a hypothetical disease and then viewed one of four survival graphs that displayed mortality risks with and without treatment. Survival graphs showed either a visually large or visually small difference between treatments and were labeled to represent either 5‐year or 15‐year risk statistics. Participants then provided ratings of disease seriousness, as well as treatment effectiveness for each possible treatment. Variations in ratings corresponded more with visual dissimilarity than with changes in the statistical risk exhibited, with participants perceiving somewhat greater disease seriousness and significant differences in treatment effectiveness in large visual difference graphs. We conclude that when people interpret survival curves, they often fail to sufficiently account for the timeframe represented and perceive more risk and larger differences when identical risks are displayed over longer periods of time. We recommend that all presentations of survival graphics, whether to patients, physicians, or scientists, emphasize duration information (e.g., in the title) and remind readers that attending to graph axis labels is the only way to pierce these visual illusions.
Communicating Asset Risk: How Name Recognition and the Format of Historic Volatility Information Affect Risk Perception and Investment Decisions
Authors: Weber Elke U. , Siebenmorgen Niklas , Weber Martin
Published: July 2005

An experiment examined how the type and presentation format of information about investment options affected investors' expectations about asset risk, returns, and volatility and how these expectations related to asset choice. Respondents were provided with the names of 16 domestic and foreign investment options, with 10‐year historical return information for these options, or with both. Historical returns were presented either as a bar graph of returns per year or as a continuous density distribution. Provision of asset names allowed for the investigation of the mechanisms underlying the home bias in investment choice and other asset familiarity effects. Respondents provided their expectations of future returns, volatility, and expected risk, and indicated the options they would choose to invest in. Expected returns closely resembled historical expected values. Risk and volatility perceptions both varied significantly as a function of the type and format of information, but in different ways. Expected returns and perceived risk, not predicted volatility, predicted portfolio decisions.
Risk Perception of Heavy Metal Soil Contamination by High‐Exposed and Low‐Exposed Inhabitants: The Role of Knowledge and Emotional Concerns
Authors: Grasmück Dirk , Scholz Roland W.
Published: July 2005

Soil contaminated with heavy metals is a salient example of environmental risk. Consumption of vegetables cultivated in contaminated soil or direct ingestion of soil by small children can damage health. In contrast to other kinds of pollution or risks such as air pollution or exposure to ozone, the individual risk concerning soil contamination is highly dependent on the way one is exposed to the local source of risk. Thus, we wanted to know if risk perception varies according to the level of exposure. A quasi‐experimental, questionnaire‐based study was conducted in a community in northwest Switzerland, where the soil is widely contaminated. The level of contamination varies with the distance from the source of the contamination, a metal processing plant. We investigated the perception of risk of heavy‐metal‐contaminated soil by inhabitants with high‐exposure levels (N= 27) and those with low‐exposure levels (N= 30). Both groups judged the risk for oneself similarly whereas the low‐exposure group, when compared to the high‐exposure group, judged perceived risk for other affected people living in their community to be higher. Besides this exposure effect, risk perception was mainly determined by emotional concerns. Participants with higher scores in self‐estimated knowledge tended to provide low‐risk judgments, were less interested in further information, showed low emotional concern, and thus displayed high risk acceptance. In contrast, actual knowledge showed no correlation with any of theses variables. Judgments on the need for decontamination are determined by risk perception, less application of dissonance‐reducing heuristics and commitment to sustainability. The desire for additional information is not affected by missing knowledge but is affected by emotional concerns.
Actively regulating bioengineered tissue and organ formation
Authors: Mooney DJ , Boontheekul T , Chen R , Leach K
Published: July 2005

Structured Abstract

Authors –  Mooney DJ, Boontheekul T, Chen R, Leach K

Objectives –  Describe current and future approaches to tissue engineering, specifically in the area of bone regeneration. These approaches will allow one to actively regulate the cellular populations participating in this process.

Design –  Many approaches to actively regulate cellular phenotype are under exploration, and these typically exploit known signal transduction pathways via presentation of specific receptor‐binding ligands, and may also deliver mechanical information via the physical bridge formed by the receptor‐ligand interactions. Cellular gene expression may also be directly modulated utilizing gene therapy approaches to control tissue regeneration.

Conclusions –  Significant progress has been made to date in bone regeneration using inductive molecules and transplanted cells, and FDA approved therapies have resulted. While approaches to date have focused on delivery of single stimuli (e.g. one growth factor), future efforts will likely attempt to more closely mimic developmental processes by the delivery of multiple inputs to the cells in spatially and temporally regulated fashions.
Bone – special problems of the craniofacial region
Authors: Herring SW , Ochareon P
Published: July 2005

Structured Abstract

Authors – Herring SW, Ochareon P

Problems – The craniofacial region presents special problems for tissue engineering. First, the stresses and strains that engineered tissues will encounter are mostly unknown. Second, if tissue engineering is to be useful in ameliorating craniofacial anomalies, it will have to mimic the growth activity of the native tissues. These problems are interrelated in that bone growth responds to loading conditions.

Methods – Our work uses miniature technology to measure skull deformation during function in the miniature pig. Growth is quantified in the same animals by labeling replicating cells with bromodeoxyuridine and newly mineralized bone with fluorochromes. The mandibular condyle and the cranial sutures are both candidate areas for tissue engineering, and craniofacial periosteum is a promising graft material.

Results – The condyle is compressed by the reaction load at the temporomandibular joint (TMJ). Cell divisions in the perichondrium are negatively correlated with bone strain. Craniofacial sutures deform during function much more than adjacent bones, and strains can be either tensile or compressive. In contrast to expectation, functional tension is not correlated with sutural growth rate. However, functional strain does predict sutural morphology, with compressed sutures showing complex interdigitation. Periosteum shows striking differences between resorptive and appositional surfaces. The resorptive medial side of the zygomatic arch is under pressure during function. Tensile strain perpendicular to the surface is probably greater on the temporal than on the zygomatic bone, thus correlating with more rapid periosteal apposition on the temporal.

Conclusion – Engineered implants may be more likely to succeed if their architecture suits the strain environment in which they will function.
Bioreactor cultivation of osteochondral grafts
Authors: Vunjak‐Novakovic G , Meinel L , Altman G , Kaplan D
Published: July 2005

Authors –  Vunjak‐Novakovic G, Meinel L, Altman G, Kaplan D

The clinical utility of tissue engineering depends upon our ability to direct cells to form tissues with characteristic structural and mechanical properties across different hierarchical scales. Ideally, an engineered graft should be tailored to (re)establish the structure and function of the native tissue being replaced. Engineered grafts of such high fidelity would also foster fundamental research by serving as physiologically relevant models for quantitative in vitro studies. The approach discussed here involves the use of human mesenchymal stem cells (hMSC) cultured on custom‐designed scaffolds (providing a structural and logistic template for tissue development) in bioreactors (providing environmental control, biochemical and mechanical cues). Cartilage, bone and ligaments have been engineered by using hMSC, highly porous protein scaffolds (collagen; silk) and bioreactors (perfused cartridges with or without mechanical loading). In each case, the scaffold and bioreactor were designed to recapitulate some aspects of the environment present in native tissues. Medium flow facilitated mass transport to the cells and thereby enhanced the formation of all three tissues. In the case of cartilage, dynamic laminar flow patterns were advantageous as compared to either turbulent steady flow or static (no flow) cultures. In the case of bone, medium flow affected the geometry, distribution and orientation of the forming bone‐like trabeculae. In the case of ligament, applied mechanical loading (a combination of dynamic stretch and torsion) markedly enhanced cell differentiation, alignment and functional assembly. Taken together, these studies provide a basis for the ongoing work on engineering osreochondral grafts for a variety of potential applications, including those in the craniofacial complex.
Advances in skeletal tissue engineering with hydrogels
Authors: Elisseeff J , Puleo C , Yang F , Sharma B
Published: July 2005

Structured Abstract

Authors –  Elisseeff J, Puleo C, Yang F, Sharma B.

Objectives –  Tissue engineering has the potential to make a significant impact on improving tissue repair in the craniofacial system. The general strategy for tissue engineering includes seeding cells on a biomaterial scaffold. The number of scaffold and cell choices for tissue engineering systems is continually increasing and will be reviewed.

Design –  Multilayered hydrogel systems were developed to coculture different cell types and develop osteochondral tissues for applications including the temporomandibular joint.

Experimental variable –  Hydrogels are one form of scaffold that can be applied to cartilage and bone repair using fully differentiated cells, adult and embryonic stem cells.

Outcome measure –  Case studies represent an overview of our laboratory's investigations.

Results –  Bilayered scaffolds to promote tissue development and the formation of more complex osteochondral tissues were developed and proved to be effective.

Conclusion –  Tissue engineering provides a venue to investigate tissue development of mutant or diseased cells and potential therapeutics.
Intraoperative Detektion von Sentinel‐Lymphknoten beim malignen Melanom der Haut‐Vitalfärbung allein versus Vitalfärbung plus Gammasonde
Authors: Kretschmer Lutz , Peeters Sabine , Beckmann Iris , Thoms Kai‐Martin , Mitteldorf Christina , Emmert Steffen , Sahlmann Carsten‐Oliver , Bertsch Hans Peter , Neumann Christine , Meller Johannes
Published: July 2005

Hintergrund: Im Vergleich zur alleinigen Vitalfärbung der Lymphabflusswege bei der Sentinel‐Lymphknotendissektion hat die intraoperative Anwendung einer Gamma‐Detektionssonde die Identifikationsraten verbessert. In der vorliegenden retrospektiven Studie wird der Einfluss der Gamma‐Detektion hinsichtlich weiterer Aspekte ausführlich analysiert.

Patienten und Methodik: 81 Patienten, bei denen zur intraoperativen Detektion des Sentinel‐Lymphknotens (SLK) ausschließlich Patentblau zum Einsatz kam, wurden mit 247 Patienten verglichen, bei denen zusätzlich eine Gamma‐Sonde verwendet wurde.

Ergebnisse: Die Einführung der Gamma‐Sonde erbrachte eine Steigerung der SLK‐Detektionsrate von 87,7 % auf 99,2 % (P < 0,00001). Die Zahl der exzidierten SLK erhöhte sich von 1,4 ± 0,9 auf 1,8 ± 0,09 (P < 0,00001). Die „klinische Falsch‐negativ‐Rate” sank von 15,8 % auf 9,6 %. Die Positivitätsrate der komplettierenden Lymphknotendissektion sank von 50 % auf 26,6 %. Die Gamma‐Sonden‐gesteuerte Präparation hatte weniger Serome zur Folge (5,1 % versus 15 %, P = 0,01). Die Überlebens‐ und Rezidivraten nach alleiniger Vitalfärbung bzw. zusätzlicher Gamma‐Detektion unterschieden sich nicht signifikant. Die Wahrscheinlichkeit, innerhalb von 5 Jahren ein Rezidiv im Lymphknotengebiet zu entwickeln war 7,9 % nach negativer SLK‐Dissektion und 25,3 % nach positiver SLK‐Dissektion mit anschließender komplettierender Lymphknotendissektion.

Schlussfolgerungen: Der kombinierte Einsatz von Vitalfärbung und Gamma‐Sonde erhöhte die Sensitivität und senkte das Risiko der postoperativen Seromentwicklung, war aber ohne signifikanten Einfluss auf die Rezidiv‐ und Überlebensraten.
Les subventions des taux d'intérêt et le prix de la terre agricole au Québec
Authors: Romain Robert , Roy Claude , Larue Bruno , Gunjal Kisan
Published: July 2005

Cet article analyse les variables influençant le prix de la terre agricole au Québec et analyse, plus spécifiquement, l'impact des taux d'intérêt sur emprunt puisque ce dernier est subventionné au Québec. On propose un modèle tenant compte de l'activité agricole et de l'activité non agricole. Un impact positif des recettes agricoles sur le prix de la terre est principalement noté dans les régions près des centres urbains où l'agriculture est concentrée, soit en périphérie de Montréal et dans la région de Québec. Les sources de revenus non agricoles ont un impact significatif sur le prix des terres settlement dans la région la plus urbaine, soit prés de Montréal. Selon les coefficients de flexibilité calculés et les taux d'intérêt en vigueur au cours de la période étudiée, l'abolition des subventions du taux d'intérêt pourrait initier une chute de l'ordre de 15% a court terme et de 7% a long terme du prix de la terre dans les régions de Québec et de Montreal.
Participation, Trip Frequency and Site Choice: A Multinomial‐Poisson Hurdle Model of Recreation Demand
Authors: Yen Steven T. , Adamowicz Wiktor L.
Published: July 2005

Data used in recreation demand modeling are characterized by the facts that trip frequencies are non‐negative integers and that consumers are often faced with alternative destinations. This paper considers these features by estimating a multivariate recreation demand model that accounts for trip frequency and choice among alternative recreation sites using a mixed multinomial‐Poisson hurdle distribution. The specification of the Poisson hurdle distribution at the aggregate level accounts for participation and trip frequency, and avoids the restrictive mean‐variance property of the basic Poisson model. The model is estimated using data from Bighorn sheep hunters in Alberta, Canada. Simulation results suggest that changing price and quality variables cause substitution among sites. The welfare implications of changes in these variables are also examined.
Linear Input Aggregation Bias in Nonparametric Technical Efficiency Measurement
Authors: Thomas Arthur C. , Tauer Loren W.
Published: July 2005

An attraction of the nonparametric approach to measuring technical efficiency is that no a priori structure is placed on the production process of the firm. However, inputs are typically linearly aggregated, either explicitly or implicitly. It is shown that this introduces bias in the technical efficiency measurement. The computed technical efficiency measure becomes an economic efficiency measure comprised of both technical and allocative efficiency. An empirical application demonstrates the bias.
Seasonal Patterns and Regional Preferences in Japanese Household Demand for Seafood
Authors: Wessells Cathy Rohein , Wilen James E.
Published: July 2005

This study addresses the little analyzed Japanese consumer demand for seafood. A demand system approach is used to analyze demand for a group of seafood products that make up the representative household's total expenditures on seafood for at‐home consumption. The linear approximate Almost Ideal Demand System (U/AIDS) is applied to monthly data from 1980 through 1989 on the demand for seafood for three representative households: the average Japanese household, northern Japanese household, and southern Japanese household. Estimation results highlight effects of seasonality on demand for various seafood products; how seasonality effects defer by region; and differences in demand elasticities for seafood products both during the marketing year and across regions. Results from the analysis of the nationally representative household are contrasted with results from regionally representative house‐holds to determine implications of viewing Japan as a single, homogeneous market.
On the Cost of Chasing Research Dollars
Authors: McKenney Daniel W.
Published: July 2005

Most researchers face the chore of seeking finding. Competitive grants are increasingly the norm for funding, even in large national research organizations. This paper presents the results of an analysis of the direct costs of grant‐seeking behavior in the context of Canada s national forest research organization. Unit costs of obtaining additional research dollars from a particular competition are derived. The average cost is found to be 22 cents per research dollar received. However, this result is heavily contingent on assumptions about the opportunity costs of researchers' time.
Supply Management: The Past and Future
Authors: Schmitz Andrew , Schmitz Troy G.
Published: July 2005

This paper reviews many of the controversial issues surrounding supply management in the Canadian dairy and poultry sectors. In this context, the underlying theory is extended to include decision making where both joint production and import controls are in place. Also the supply management system is discussed within a rent‐seeking framework. This provides both a method by which to analyze the various forces that will either keep the supply management system in operation or lead to its demise, as well as a means by which supply management can be improved. Concerning the former, it appears, for example, that the tariffs under the General Agreement on Tariffs and Trade are sufficiently high that producers are better off with supply management than with a system with no production controls. If this system falls apart, it will largely be due to internal fighting among provinces and/or producers over expanded market share.
Evolving Dynamic Relationships Between the Money Supply and Food‐Based Prices in Canada and the United States
Authors: Larue Bruno , Babula Ronald A.
Published: July 2005

The objective of this paper is to analyze the relationships between the money supply and food‐based prices (farm input, farm output, retail food prices) and shed some light on contradictory results in the literature by performing the analysis on two countries, testing and allowing for structural change, and decomposing long‐run relationships in terms of speed of adjustment and adjustment amount. Money neutrality is rejected for all of the periods in both countries. However, some of the required conditions for money neutrality held temporarily in the U. S. This could be attributed to differences in policy‐induced market signal distortions. In both countries, demand‐pull forces have grown stronger, and the cost‐push forces have grown weaker. In Canada, this is consistent with a growing and more concentrated retail sector exercising price leadership on farm input and farm output prices.
The Wheat War of 1994
Authors: Alston Julian M. , Gray Richard , Sumner Daniel A.
Published: July 2005

Following the signing of the 1989 Canada–United States Free Trade Agreement, sales of Canadian wheat to the United States grew rapidly. This resulted in a series of trade disputes, culminating in an investigation by the U.S. International Trade Commission (USITC) into the impacts of U.S. imports of Canadian wheat on the U.S. wheat farm program. A USITC finding of “material interference” would have led to a recommendation to implement tariffs or quantitative restrictions against Canadian wheat under Section 22 of the U.S. farm program legislation. The U.S. Department of Agriculture (USDA) claimed such material interference, but the U.S. flour millers, pasta makers and grain handlers, along with Canadian grain industry interests, testified that the true effects of imports are in the order of one–tenth of the effects claimed by the USDA. USITC staff analysis led to intermediate estimates of effects. This study explores the impacts of Canada–U.S. wheat trade on U.S. wheat prices and program costs, explains some of the differences in measured effects, and reports the outcome of the dispute.
Welfare Impacts of the Canada‐U.S. Softwood Lumber Trade Dispute: Beggar Thy Consumer Trade Policy
Authors: Myneni Giridhar , Dorfman Jeffrey H. , Ames Glenn C. W.
Published: July 2005

The welfare impacts of the 1987–91 Canadian “voluntary” 15% lumber export tax and the current 6.51 % U. S. import duty are analyzed using a simultaneous equations model of the softwood lumber market. The results show that U.S. consumers suffer losses 35% to 45% of those endured by Canadian producers. Canadian national welfare was much higher under the voluntary export tax, indicating the Canadian government erred in unilaterally terminating the agreement. In both instances, the U.S. government pursued policies that benefited domestic producers at the expense of U.S. lumber consumers, with no attempt or discussion of compensation. Thus, this appears to be a case of “beggar thy consumer” trade policy.
Testing for Dynamic Misspecification of Input Demand Functions: An Application to Canadian Agriculture
Authors: Vasavada Utpal , Thijssen Geert
Published: July 2005

Previous applications of the inter‐temporal quadratic adjustment cost model in agriculture have failed to consider information gained from pre‐testing in choosing an appropriate specification for dynamic demand of quasi‐fixed inputs. A test strategy is outlined taking account of this information in order to consistently estimate adjustment cost and discount rate parameters. Canadian agricultural data are used in the empirical analysis. Test results suggest that the intertemporal quadratic adjustment cost model is inappropriate for modeling dynamic demand for land, labor and machinery.
Agricultural Producer Price Expectations
Authors: Sulewski Travis , Sprigs John , Schoney R. A.
Published: July 2005

Producer price expectations underlie much of agricultural supply analysis. While producer price expectations would ideally be discovered experimentally, this is too costly. Instead, producer price expectations are usually represented in agricultural supply analysis by easily obtained hypothesized expectation formulations. In most cases, the hypothesized expectation formulations are functions of past prices. However, other formulations are sometimes used, such as current cash and futures prices, or initial payments in the case of grains marketed by the Canadian Wheat Board. This paper compares actual producer price expectations with a variety of hypothesized expectation formulations for wheat and canola in Saskatchewan. A test developed by Granger is used to determine the proxy models that are significantly dominant. The model that dominates as a proxy in the case of wheat price expectations is the two‐year declining‐weight moving average. The two models that dominate as a proxy in the case of canola price expectations are the first‐order autoregressive and, as well, the two‐year declining‐weight moving average. There is no significant difference between the two models. Somewhat surprising is the performance of formulations based on futures prices. These formulations perform very poorly in representing producers' price expectations, even though they are found to be among the most accurate predictors of actual commodity prices. An even more interesting observation is the performance of the futures price model in the canola market. Even though the November contract in January explains very little of the variation in the actual commodity prices for that year, its error in predicting canola prices is not significantly greater than that of the best performing, the four‐year declining‐weight moving average, based upon the root mean squared error criterion.
An Evaluation of the Ontario Farm Business Management Association Program
Authors: Howard Wayne H. , Filson Glen C.
Published: July 2005

The Ontario Farm Business Management Association (FBMA) program was initiated to improve the business management skills of Ontario red meat producers. The program has three aims:

to increase management skills on the farm

to increase management skills in the private sector

to help farmers make use of private sector advice.

Two methods were used to evaluate the program. First, FBMA members and other red meat producers were surveyed about their farm and personal characteristics as well as use farm records and information sources. Second, focus groups were held with the FBMA field persons. Results indicate that membership in an FBMA increased the collection and use of farm records, but that there was no significant increase in the use of private sector consultants by the producers. Moreover, FBMA members indicated a very low willingness to pay to support their FBMA if government funding were stopped.
Comparaison de la rentabilité des enterprises céréalières biologiques et en transition par rapport aux entreprises conventionnelles au Québec
Authors: Paillat Nicolas , Pellerin M. Doris , Perrier Jean Philippe , Levallois Raymond
Published: July 2005

Les données financières de 92 entreprises agricoles conventionnelles produisant un minimum de 20 hectares de céréales à paille et de 21 entreprises, biologiques ou en phase de transition avancée, cultivant au moins 15 hectares de céréales ont été extraites de la banque de données Agritel pour fins de comparaison. À partir des entreprises conventionnelles, quatre groupes sont formes: bas niveau d'intrants (BNI), haut niveau d'intrants (HNI), rendement faible (extensif) et rendement eleve (intensif).

Pour l'ensemble des céréales, ainsi que pour l'orge, les entreprises biologiques obtiennent des rendements et des charges significativement plus faibles par rapport á l'ensemble des entreprises conventionnelles. Ainsi, les marges brutes sont équivalentes. La dépendence des entreprises biologiques et conventionnelles vis‐à‐vis des aides gouvemementales contribue toutefois pour une part importante aux résultats obtenus. La rentabilité des entreprises biologiques est comparable à celle des entreprises conventionnelles au niveau global de l'entreprise.

Par rapport aux quatre sous‐groupes formés, le groupe biologique se situe, pour les marges brutes sur les cultures entre les groupes les plus performants (groupes BNI et intensif) et les moins rentables (groupes HNI et extensif).

Des logiques de production totalement différentes peuvent done aboutir à des résultats économiques similaires, du moins á court terme.
Generic Advertising; and the Structural Heterogeneity Hypothesis
Authors: Kinnucan Henry W. , Venkateswaran Meenakshi
Published: July 2005

This paper adduces and tests the hypothesis that generic advertising responses are dynamic, i.e., are subject to change over time due to changes in target audiences, managerial expertise, copy quality or other time‐related factors. Specifically, the authors consider the structural heterogeneity hypothesis from the perspective of three alternative econometric models that permit random and systematic time‐varying response: the Prescott‐Cooley model, the return‐to‐normality model, and the stochastic‐trend model. A distinguishing characteristic of the models is the presence or absence of heteroscedasticity. Based on pretests, which failed to detect heteroscedasticity, a modified version of the stochastic‐trend model is selected for hypothesis testing. Results based on data of the first 15 years of the Ontario fluid milk campaign suggest advertising responses are dynamic. Estimated advertising elasticities decline more or less monotonically over this sample period, from a high of 0.020‐o.031 in the initial 1973–74 theme period, to a low of 0.0004‐0.009 in the final 1986–87 theme period. The apparent declining effectiveness of the Ontario fluid milk campaign is consistent with wearout theory, and suggests that program managers may want to reassess marketing strategies to identify possible ways to improve performance. Given the importance of advertising elasticities in normative decision models and the growing evidence of structural heterogeneity, models that permit parameters to change over time should provide an improved basis for program assessment and resource allocation.
A Microeconometric Analysis of the U.S. Meat Demand
Authors: Gao X. M. , Spreen Thomas
Published: July 2005

Price and expenditure elasticities and estimates of the effect of household demographic variables on U.S. meat demand are estimated using the newly released 1987–88 USDA household food consumption survey data. The USDA survey for the first time included variables reflecting respondents' concerns for health and diet information. A hybrid demand system, which combines a modified generalized addilog system and a level version Rotterdam demand system, is developed as the analytical framework. The micro econometric analysis takes into consideration the consumer selection problem, the missing‐price problem, and the aggregation and quality variation problem. The most significant household characteristic and socio‐economic variables are region, ethnic background, household size, urbanization, food planner, received health information, female household head employment status and proportion of food expenditure on away‐from‐home consumption. The results support the speculation of other time‐series meat demand studies claiming both health concerns and convenience are the reasons for changes in consumer preference in favor of poultry and fish and in disfavor of red meat.