Impact of Foodborne Illness Outbreaks on Price Transmission, U.S. Price Linkages in the International Wheat Market, and Spatial Price Dynamics in the U.S. Vegetable Sector
Notice bibliographique
Résumé
In the first essay, a regime switching error correction model is applied to weekly shipping point and terminal market spinach prices in order to assess the spatial price transmission impact of the 2006 E. coli outbreak on the U.S. fresh spinach market. A food safety index (FSI) related to the outbreak is calculated and used as the regime switching mechanism for 11 alternative farm-to-wholesale spatially separated market pairs. Results suggest not all markets responded uniformly to the FSI. The majority of the markets with alternative sources of spinach exhibited nonlinearities, while those which were primarily supplied by California producers did not. In general, shorter adjustment speeds were seen in terminal markets that were closer in proximity to the California shipping point. Southern market pairs exhibiting threshold behavior saw increased efficiency after the outbreak (potentially due to increased self-regulation), while the remaining pairs saw a loss in efficiency. In the second essay, through applying time-series modeling techniques to weekly wheat prices, we evaluate the long-run price dynamics between the U.S. and other large wheat exporters, including the E.U., Canada, Australia, Argentina, and the Black Sea region. Testing for cointegration lead to the conclusion that aside from Canada, U.S. hard red winter wheat prices are cointegrated with the other top exporters and aside from Canada and Australia, U.S. soft red winter wheat prices are cointegrated with the other top wheat exporters. Threshold and asymmetric behavior were not present in the long-run relationship between the top exporters. In addition, Granger causality tests indicated that the U.S. has a significant impact on wheat prices in Argentina, Australia, the E.U., and even in the Black Sea region. Price transmission elasticities were all estimated to be above 0.78, and suggest the possibility that trade barriers are still preventing optimal market efficiency. The third essay investigates price transmission behavior in the U.S. fresh vegetable market, in particular looking at the top five vegetables consumed, including carrots, lettuce, onions, potatoes, and tomatoes. An asymmetric variable threshold autoregressive model (AvTAR) was used to estimate the price relationships between 54 separate terminal market pairs, while the parity bounds model (PBM) was used to estimate the probability of 28 shipping point to terminal market pairs behaving efficiently. Results for the AvTAR model provide evidence that the level of perishability impacts the level of market integration and of a common trend of increasing transaction costs among nearly 70% of the markets studied. Results for the PBM indicate that 18% of the markets studied had more than a 10% probability of behaving inefficiently, indicating that while the majority of markets behaved efficiently, there is room for improvement.
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Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,001 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,026 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».