bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification of Economies of Scope in a Stochastic Production Environment
Authors: Curtis Rita E. , Sarmiento Camilo 
Published: July 2005

This paper extends the definition of economies of scope to multioutput firms that face an uncertain production environment. Identification of economies of scope in this environment, however, requires separability assumptions on the technology. These identification restrictions are demonstrated in the paper. For each identification restriction, the definition of economies of scope is generalized to the case of uncertain production and risk aversion.L'article que voici élargit la définition des économies de gamme aux entreprises à produits multiples aux prises avec une situation incertaine au niveau de la production. Pour cerner les économies de gamme dans une telle situation, il faut poser l'hypothèse de la séparation des technologies. Les auteurs illustrent ces restrictions et généralisent la définition des économies de diversification pour chacune d'elles dans le cas d'une production incertaine et de l'aversion du risque.
Agro‐Climatic Conditions and Regional Technical Inefficiencies in Agriculture
Authors: Demir Nazmi , Mahmud Syed F. 
Published: July 2005

A survey of applications of the Technical Inefficiency Effects (TIE) model suggests that agro‐climatic and other environment variables are customarily omitted in the model specifications. The justification for such an omission is the assumption that these variables are beyond the control of the farmers and therefore should be treated as random variables. In this paper, we argue that in applications dealing with regional agricultural data, agro‐climatic variables should not be treated as pure random terms. Historical differences in agro‐climatic conditions are known with a reasonable degree of certainty across a larger region. Therefore, omission of such variables from the analysis may lead to inaccurate interregional technical inefficiency comparisons. In order to demonstrate the importance of agro‐climatic variables in such analyses, we estimate the TIE model for Turkey. A translog stochastic frontier production function with agro‐climatic variables such as rainfall and land quality is estimated, and it is shown not only that the agro‐climatic variables are statistically significant but also that their omission substantially affects mean output elasticities and relative technical efficiencies.Une étude sur les applications du modèle de l'effet d'inefficacité technique (EIT) laisse à supposer que les variables agro‐climatiques et les autres variables environnementales sont comme d'habitude omises dans les spécifications du modèle. Une telle omission est justifiée par l'hypothèse selon laquelle ces variables sont en dehors du contrôle des fermiers et devraient être considérées comme des variables aléatoires. Dans ce communiqué, nous affirmons que dans les applications concernant les données agricoles régionales, ces variables agro‐climatiques ne doivent pas être traitées comme de simples termes aléatoires. Les différences historiques dans les conditions agro‐climatiques sont connues avec un degré raisonnable de certitudes pour une grande région. Aussi l'omission de telles variables dans l'analyse peut‐elle donner lieu à de fausses comparaisons interrégionales d'inefficacité technique. Afin de démontrer l'importance des variables agro‐climatiques dans de telles analyses, nous considérons le modèle de l'effet d'inefficacité techniques de la Turquie. II s'agit d'une fonction de production frontalière translogue et stochastique avec des variables agro‐climatiques telles que la pluviosité, la qualité de sol et d'autres variables. Nous démontrons que les variables agro‐climatiques sont non seulement importantes statistiquement, mais que leur omission influence essentiellement les élasticités moyennes de production ainsi que les efficacités techniques relatives.
Functional Eating and Strategic Groups in Canada
Authors: Cloutier L. Martin , Salves Anne‐Laure 
Published: July 2005

The emergence of the nutraceuticals and functional foods (NFFs) products is a challenge to economists and management scientists interested in studying the evolution of the sector. There are profound issues in product and in market classification. This paper reports the results of an exploratory study that illustrates the use of strategic groups as a means to research this emerging industry, using a sample of 280 companies in Canada. The analysis identifies six main strategic groups within the NFFs sector that compete on the market, product and capability strategic fields. The results indicate that the sector is widely heterogeneous in firm composition, markets served, and intragroup and intergroup product strategies.L'émergence de produits nutraceutiques et aliments fonctionnels (NAF) pose un défi aux économistes et aux spécialistes en sciences administratives intéressés par l'étude de I'évolution de ce secteur où perdurent de nomhreux prohlémes de classification de produits et de marchés. Cet article présente les résultats d'une étude exploratoire qui démontre la pertinence de la notion de groupe stratégique dans l'analyse d'un échantillon de 280 compagnies de ce secteur au Canada. Cette etude identifie six groupes strategiques dans le secteur des NAF en concurrence au plan des champs stratégiques de marchés, de produits et de compétences. Les résultats de la recherche montrent que le secteur est largement hétérogène au niveau de la composition des firmes, des marchés desservis et des stratégies de produits intergroupes et intragroupes.
The Effect of Producers' Risk Attitudes on Sizing the Harvest and On‐farm Drying System
Authors: Davis Todd D. , Patrick George F. 
Published: July 2005

A simulation model of an on‐farm grain harvest and drying system was used to determine net returns associated with alternative sized systems. The physical processes of corn and soybean planting, growth, harvest and drying were simulated under historical weather conditions for 33 years. Weather data determined the number of field days, physiological maturity date, harvest grain moisture, yield losses and dryer energy costs. Guidelines developed by agricultural engineers and agricultural economists were used to initially size the combine and dryer for three sizes of farms. Capacities of the combine and dryer were increased and decreased by 10, 20, 30, 40 and 50%, independently. Net returns to labor and management, reflecting yield and price correlations, were determined for each of the equipment combinations. Stochastic dominance was used to evaluate the distributions of net revenue and determine the risk efficient combine and dryer sets. It was found that there were small differences in net returns for systems that completed harvest and drying in the 27B32 day range for all three farm sizes. For a given size of farm, risk averse producers were found to prefer smaller capacity combines and dryers.Les auteurs se sont servis d'un modèle simulant la récolte et le séchage du grain à la ferme pour calculer le revenu net de systèmes de production de taille variable. Les aspects physiques de la plantation, de la croissance, de la récolte et du séchage du maïs et du soja ont été reproduits en fonction des données météorologiques relevées pendant 33 ans. Ces données ont permis d'établir le nombre de jours de croissance, la date de la maturité physiologique, la teneur en eau du grain, les pertes de rendement et le coût de l'énergie nécessaire au séchage. Ensuite, les auteurs ont suivi les recommandations des agronomes et des économistes agricoles pour déterminer les dimensions initiales de la moissonneuse et du séchoir pour trois exploitations de taille différente. La capacité de la moissonneuse et celle du séchoir ont été augmentées ou réduites indépendamment de 10, de 20, de 30, de 40 et de 50 pour cent, puis on a calculé le revenu net venant du travail et de la gestion du producteur en tenant compte de la corrélation entre le rendement et les prix pour chaque combinaison. La dominance stochastique a permis d'estimer la distribution du revenu net et d'identifier les ensembles moissonneuse/séchoir rentables en fonction du risque. Les systèmes où la récolte et le séchage sont terminés au bout de 27 à 32 jours entraînent de légères variations du revenu net, pour les trois types d'exploitation. Peu importe la taille de la ferme, l'aversion pour le risque incite le producteur à choisir une moissonneuse et un séchoir de dimensions plus modestes.
Economic‐Environmental Tradeoffs in Swine Finishing Operations
Authors: de Vos Greg W. , Weersink Alfons , Stonehouse D. Peter 
Published: July 2005

This study examines the cost effectiveness of 81 alternative manure management systems for a swine finishing operation in reducing three pollutants associated with livestock waste: ammonia, nitrogen and phosphorus. The results are presented in terms of the tradeoff between the levels of these pollutants (environmental indicator) and the economic returns to the producer. The levels of the three manure residuals cannot be reduced by more than half from the present levels under the profit‐maximizing system for each farm size. Further reduction would require changes in hog numbers to reduce the volume of manure and consequently residual levels. However, the feasible reductions in residuals can be achieved at relatively low cost. Larger farms tend to have lower abatement costs as the percentage reduction in residuals increase. The attempt to reduce more than one of the residuals simultaneously is complicated by the conflicting effects of alternative manure management systems on ammonia and nitrogen levels.L'étude évalue la rentabilité de 81 systèmes de gestion du fumier pour les élevages de porcs quant à la réduction de la concentration de trois polluants associés aux déchets animaux: l'ammoniaque, l'azote et le phosphore. Les auteurs présentent les résultats sous forme de compromis entre la concentration de polluants (indice environnemental) et le rendement de l'élevage pour le producteur. Quelle que soit la taille de l'exploitation, il est impossible de réduire la concentration des trois résidus du fumier à plus de la moitié de leur concentration actuelle dans un régime de maximisation des bénéfices. Pour réduire leur concentration davantage, il faudrait diminuer la taille du troupeau et le volume de fumier. Atteindre les réductions de concentration réalisables ne coûte cependant pas très cher. Dans les gros élevages, le coût des mesures de lutte contre la pollution a tendance à baisser avec la hausse de la réduction des résidus en pour cent. L'action contraire des différents systèmes de gestion du fumier sur la concentration d'ammoniaque et d'azote complique les efforts déployés pour réduire simultanément la concentration de plusieurs résidus.
Implications of Seasonal Climate Forecasts on World Wheat Trade: A Stochastic, Dynamic Analysis
Authors: Hill Harvey S. J. , Mjelde James W. , Love H. Alan , Rubas Debra J. , Fuller Stephen W. , Rosenthal Wesley , Hammer Graeme 
Published: July 2005

Improvements in seasonal climate forecasts have potential economic implications for international agriculture. A stochastic, dynamic simulation model of the international wheat economy is developed to estimate the potential effects of seasonal climate forecasts for various countries' wheat production, exports and world trade. Previous studies have generally ignored the stochastic and dynamic aspects of the effects associated with the use of climate forecasts. This study shows the importance of these aspects. In particular with free trade, the use of seasonal forecasts results in increased producer surplus across all exporting countries. In fact, producers appear to capture a large share of the economic surplus created by using the forecasts. Further, the stochastic dimensions suggest that while the expected long‐run benefits of seasonal forecasts are positive, considerable year‐to‐year variation in the distribution of benefits between producers and consumers should be expected. The possibility exists for an economic measure to increase or decrease over a 20‐year horizon, depending on the particular sequence of years.Le progrès des prévisions saisonnières du climat a une portée économique pour l'agriculture internationale. Un modèle stochastique et dynamique de l'économie internationale du blé est développé afin d'estimer les effets potentiels des prévisions saisonnières du climat sur la production de blé de divers pays, leurs exportations et le commerce mondial. Les études précédentes ont généralement ignoré les aspects stochastiques et dynamiques des effets liés à l'utilisation des prévisions climatiques. Cette étude montre l'importance de ces aspects. En particulier avec le libre échange l'utilisation de ces prévisions aboutit à l'augmentation des excédents dans tous les pays exportateurs. En fait, il apparaît que les producteurs accaparent une grande part de l'excédent économique créé par l'utilisation de ces prévisions. De plus, les dimensions stochastiques suggèrent que bien que les bénéfices à long terme des prévisions climatiques puissent être substantiels, on s'attend à des variations considérables d'une année à l'autre dans la distribution des bénéfices entre les producteurs et les consommateurs. Il est possible qu'un indicateur économique varie à la baisse sur 20 ans eus fonction de la séquence de variation climatique.
Zoonotic Potential of the Microsporidia
Authors: Mathis Alexander , Weber Rainer , Deplazes Peter 
Published: July 2005

SUMMARY

Microsporidia are long-known parasitic organisms of almost every animal group, including invertebrates and vertebrates. Microsporidia emerged as important opportunistic pathogens in humans when AIDS became pandemic and, more recently, have also increasingly been detected in otherwise immunocompromised patients, including organ transplant recipients, and in immunocompetent persons with corneal infection or diarrhea. Two species causing rare infections in humans,
Encephalitozoon cuniculi
and
Brachiola vesicularum
, had previously been described from animal hosts (vertebrates and insects, respectively). However, several new microsporidial species, including
Enterocytozoon bieneusi
, the most prevalent human microsporidian causing human immunodeficiency virus-associated diarrhea, have been discovered in humans, raising the question of their natural origin. Vertebrate hosts are now identified for all four major microsporidial species infecting humans (
E. bieneusi
and the three
Encephalitozoon
spp.), implying a zoonotic nature of these parasites. Molecular studies have identified phenotypic and/or genetic variability within these species, indicating that they are not uniform, and have allowed the question of their zoonotic potential to be addressed. The focus of this review is the zoonotic potential of the various microsporidia and a brief update on other microsporidia which have no known host or an invertebrate host and which cause rare infections in humans.
Diagnosis of Lyme Borreliosis
Authors: Aguero-Rosenfeld Maria E. , Wang Guiqing , Schwartz Ira , Wormser Gary P. 
Published: July 2005

SUMMARYA large amount of knowledge has been acquired since the original descriptions of Lyme borreliosis (LB) and of its causative agent,Borrelia burgdorferisensu stricto. The complexity of the organism and the variations in the clinical manifestations of LB caused by the differentB. burgdorferisensu lato species were not then anticipated. Considerable improvement has been achieved in detection ofB. burgdorferisensu lato by culture, particularly of blood specimens during early stages of disease. Culturing plasma and increasing the volume of material cultured have accomplished this. Further improvements might be obtained if molecular methods are used for detection of growth in culture and if culture methods are automated. Unfortunately, culture is insensitive in extracutaneous manifestations of LB. PCR and culture have high sensitivity on skin samples of patients with EM whose diagnosis is based mostly on clinical recognition of the lesion. PCR on material obtained from extracutaneous sites is in general of low sensitivity, with the exception of synovial fluid. PCR on synovial fluid has shown a sensitivity of up to >90% (when using four different primer sets) in patients with untreated or partially treated Lyme arthritis, making it a helpful confirmatory test in these patients. Currently, the best use of PCR is for confirmation of the clinical diagnosis of suspected Lyme arthritis in patients who are IgG immunoblot positive. PCR should not be used as the sole laboratory modality to support a clinical diagnosis of extracutaneous LB. PCR positivity in seronegative patients suspected of having late manifestations of LB most likely represents a false-positive result. Because of difficulties in direct methods of detection, laboratory tests currently in use are mainly those detecting antibodies toB. burgdorferisensu lato. Tests used to detect antibodies toB. burgdorferisensu lato have evolved from the initial formats as more knowledge on the immunodominant antigens has been collected. The recommendation for two-tier testing was an attempt to standardize testing and improve specificity in the United States. First-tier assays using whole-cell sonicates ofB. burgdorferisensu lato need to be standardized in terms of antigen composition and detection threshold of specific immunoglobulin classes. The search for improved serologic tests has stimulated the development of recombinant protein antigens and the synthesis of specific peptides from immunodominant antigens. The use of these materials alone or in combination as the source of antigen in a single-tier immunoassay may someday replace the currently recommended two-tier testing strategy. Evaluation of these assays is currently being done, and there is evidence that certain of these antigens may be broadly cross-reactive with theB. burgdorferisensu lato species causing LB in Europe.
Recognition ofStaphylococcus aureusby the Innate Immune System
Authors: Fournier Bénédicte , Philpott Dana J. 
Published: July 2005

SUMMARYThe gram-positive bacteriumStaphylococcus aureusis a major pathogen responsible for a variety of diseases ranging from minor skin infections to life-threatening conditions such as sepsis. Cell wall-associated and secreted proteins (e.g., protein A, hemolysins, and phenol-soluble modulin) and cell wall components (e.g., peptidoglycan and alanylated lipoteichoic acid) have been shown to be inflammatory, and these staphylococcal components may contribute to sepsis. On the host side, many host factors have been implicated in the innate detection of staphylococcal components. One class of pattern recognition molecules, Toll-like receptor 2, has been shown to function as the transmembrane component involved in the detection of staphylococcal lipoteichoic acid and phenol-soluble modulin and is involved in the synthesis of inflammatory cytokines by monocytes/macrophages in response to these components. Nod2 (nucleotide-binding oligomerization domain 2) is the intracellular sensor for muramyl dipeptide, the minimal bioactive structure of peptidoglycan, and it may contribute to the innate immune defense againstS. aureus. The staphylococcal virulence factor protein A was recently shown to interact directly with tumor necrosis factor receptor 1 in airway epithelium and to reproduce the effects of tumor necrosis factor alpha. Finally, peptidoglycan recognition protein L is an amidase that inactivates the proinflammatory activities of peptidoglycan. However, peptidoglycan recognition protein L probably plays a minor role in the innate immune response toS. aureus. Thus, several innate immunity receptors may be implicated in host defense againstS. aureus.
Plasmodium ovale
: Parasite and Disease
Authors: Collins William E. , Jeffery Geoffrey M. 
Published: July 2005

SUMMARY

Humans are infected by four recognized species of malaria parasites. The last of these to be recognized and described is
Plasmodium ovale
. Like the other malaria parasites of primates, this parasite is only transmitted via the bites of infected
Anopheles
mosquitoes. The prepatent period in the human ranges from 12 to 20 days. Some forms in the liver have delayed development, and relapse may occur after periods of up to 4 years after infection. The developmental cycle in the blood lasts approximately 49 h. An examination of records from induced infections indicated that there were an average of 10.3 fever episodes of ≥101°F and 4.5 fever episodes of ≥104°F. Mean maximum parasite levels were 6,944/μl for sporozoite-induced infections and 7,310/μl for trophozoite-induced infections. Exoerythrocytic stages have been demonstrated in the liver of humans, chimpanzees, and
Saimiri
monkeys following injection of sporozoites. Many different
Anopheles
species have been shown to be susceptible to infection with
P. ovale
, including
A. gambiae
,
A. atroparvus
,
A. dirus
,
A. freeborni
,
A. albimanus
,
A. quadrimaculatus
,
A. stephensi
,
A. maculatus
,
A. subpictus
, and
A. farauti
. An enzyme-linked immunosorbent assay has been developed to detect mosquitoes infected with
P. ovale
using a monoclonal antibody directed against the circumsporozoite protein.
Plasmodium ovale
is primarily distributed throughout sub-Saharan Africa. It has also been reported from numerous islands in the western Pacific. In more recent years, there have been reports of its distribution on the Asian mainland. Whether or not it will become a major public health problem there remains to be seen. The diagnosis of
P. ovale
is based primarily on the characteristics of the blood stages and its differentiation from
P. vivax
. The sometimes elliptical shape of the infected erythrocyte is often diagnostic when combined with other, subtler differences in morphology. The advent of molecular techniques, primarily PCR, has made diagnostic confirmation possible. The development of techniques for the long-term frozen preservation of malaria parasites has allowed the development diagnostic reference standards for
P. ovale
. Infections in chimpanzees are used to provide reference and diagnostic material for serologic and molecular studies because this parasite has not been shown to develop in other nonhuman primates, nor has it adapted to in vitro culture. There is no evidence to suggest that
P. ovale
is closely related phylogenetically to any other of the primate malaria parasites that have been examined.
Covariation in the socioeconomic determinants of self rated health and happiness: a multivariate multilevel analysis of individuals and communities in the USA
Authors: Subramanian S V , Kim Daniel , Kawachi Ichiro 
Published: July 2005

Objective:To investigate individual level determinants of self rated health and happiness, as well as the extent of community level covariation in health and happiness.Design:Multivariate multilevel regression analysis of self rated poor health and unhappiness at level 1, nested within 24 118 people at level 2, nested within 36 communities at level 3. Data were obtained from the 2000 social capital benchmark survey.Setting:USA communities.Participants:24 118 adults.Main outcome measures:Self reported fair/poor health; and a single item measure of subjective wellbeing.Results:Controlling for demographic markers, a strong income and education gradient was seen for self rated poor health and unhappiness, with the gradient being stronger for poor health. Community level correlations between self rated poor health and happiness were stronger (0.65) than the individual level correlations (0.16) between the two outcomes.Conclusion:Poor health and unhappiness are highly positively correlated within individuals, and communities that are healthier tend to be happier and vice versa.