1,735 research outputs found
MODELLING THE DYNAMICS OF PRODUCTION ADJUSTMENT TO SHORT-TERM MARKET SHOCKS
Models of agricultural economics typically operate at an annual basis or in a static equilibrium framework where inputs, outputs and their prices may change considerably. Production dynamics, however, imply that models relying on spatial and temporal aggregation do not capture the effects of biological constraints in the short run. This paper examines short and long-term impacts of demand and production cost shocks in the pig sector. The analysis is carried out with a dynamic programming model which takes into account changes in export and domestic demand and market clearing price. It optimizes the supply of piglets on a monthly basis. Econometric techniques are used to estimate demand functions. Short-term negative market shocks can already have significant income effects to agricultural producers. We simulated effects of pig meat export bans of different degrees due to livestock epidemics. Full closure of export markets for six months cost pig sector €21 million.pig, demand, dynamic programming, export, livestock epidemics, price, supply, Demand and Price Analysis, Livestock Production/Industries, Production Economics, Risk and Uncertainty,
Market implications of FMD epidemics in the Finnish pig sector: Does market structure matter?
This paper examines the role of market coordination and market distortions caused by a hypothetical FMD outbreak in the Finnish pig sector. By using stochastic dynamic programming, it simulates the consequences of two outbreak scenarios (large vs. small) under two distinct market regimes (competitive market vs. monopoly in the domestic supply). Simulated losses depend on the magnitude of outbreak and expected duration of possible turndown of meat exports, whereas market regime has a limited impact.Foreign trade, livestock epidemics, dynamic programming, Livestock Production/Industries,
Additive decomposability of functions over abelian groups
Abelian groups are classified by the existence of certain additive
decompositions of group-valued functions of several variables with arity gap 2.Comment: 17 page
Differential Expression Of Gap Junction mRNAs And Proteins In The Developing Murine Kidney And In Experimentally Induced Nephric Mesenchymes
The expression of three gap junction (GJ) proteins, alpha-1 (Cx43), beta-1 (Cx32), and beta-2 (Cx26), and their transcripts were examined during the ontogeny of the mouse and rat kidney. These proteins were expressed in two non-overlapping patterns. The alpha-1 GJ protein was first observed in mesenchymal cells in the 12-day mouse kidney. By day 14 and thereafter, the ai protein was detected in the transient S-shaped bodies, but not in the podocytes of the maturing glomeruli. After birth the antigen was retained in a small subset of secretory tubules.The beta-1 and beta-2 GJ proteins were similar in their developmental patterns. They were first detected in a small subset of secretory tubules in the subcortical zone of day 17 embryos. These tubules were identified by immunohistochemical markers to be proximal. At birth, practically all proximal tubules expressed the two antigens.This analysis of GJ proteins was consistent with the results of S1 nuclease protection assays showing that, while the alpha-1 mRNA appeared early during kidney development and declined around birth, the two beta mRNAs appeared later and became intensified during the last days of intrauterine development.In experimentally induced metanephric mesenchymes, a transient expression of the alpha-1 GJ protein was seen during the segregation of the tubular anlagen. beta-1 and beta-2 GJ proteins were not detected in such induced mesenchymes cultivated up to 7 days.These observations provide evidence for the cell-specific utilization of different GJ genes during different stages of kidney organogenesis. The alpha-1 gene is activated during the early segregation of the secretory tubule and might contribute to its compartmentalization, while the beta-1 and beta-2 gene products are not detected until advanced stages of development. The latter gene products might be correlated with the physiological activity of the proximal tubules in vivo, as they are not expressed in experimentally induced tubules detectable with markers for proximal tubules
Multi-level responses of Macoma balthica to recurring hypoxic disturbance
The frequency of seasonal and short-term hypoxia is increasing in coastal seas. How such repeated disturbances affect key species that have important roles for ecosystem processes and functions remains, however, unknown. By performing a field experiment we explored if the bivalve Macoma balthica can cope with short-term, recurring hypoxic stress, and investigated how hypoxia affects the condition of surviving bivalves. By combining data on different levels of biological organization, i.e., on physiology (biomarker response), behaviour and demography, we identified stress responses before the population declined. One pulse of hypoxic disturbance (3 days) resulted in behavioural alterations, as adult M. balthica extended their siphons, emerged towards the sediment surface and expressed decreased reburial rates. However, the demographic structure of the population remained unaltered. Several pulses of recurring hypoxic stress resulted in physiological response with changes in glutathione reductase and acetylcholinesterase enzyme activities. The recurring hypoxic disturbance was observed to affect juvenile bivalves before adults, while pro-longed hypoxia reduced the entire bivalve population. Our results clearly show that hypoxic stress changes the behaviour and physiology of M. balthica before demographic changes occur, which is likely to have severe implications for the contribution of this key species to ecosystem functioning. That a combination of measures at different levels of organization can detect disturbances at an early stage suggests that such an approach would be useful for assessing the effects of disturbances on marine ecosystems that are increasingly affected by anthropogenic change.peerReviewe
Contaminated by war : A brief history of sea-dumping of munitions
Munitions introduced to the sea during military activities, including naval combat and mine warfare represent only a fraction of military material present in seas and oceans. Huge amounts of obsolete conventional munitions and chemical munitions were dumped to the sea until 1975, when London convention put a stop of sea dumping. Such munitions are a threat for maritime workers, but also for environment. Corroding shells release toxic degradation products to sediments and bottom water, and unlike other contaminants, they cannot be reduced by land measures. Only removal of source can reduce the contamination. Much work has been done in the last decade, and mechanisms of toxicity and bioaccumulation are being recognized, as well as transport and spreading mechanisms. The full assessment of the risk associated with munitions now depends on broad application of developed techniques
Large deviations for a damped telegraph process
In this paper we consider a slight generalization of the damped telegraph
process in Di Crescenzo and Martinucci (2010). We prove a large deviation
principle for this process and an asymptotic result for its level crossing
probabilities (as the level goes to infinity). Finally we compare our results
with the analogous well-known results for the standard telegraph process
Patient injuries in operative rhinology during a ten-year period : Review of national patient insurance charts
Objectives: To assess factors contributing to patient injuries in operative rhinology. Design: Data of the accepted patient injury claims involving operative rhinology, between the years 2001 and 2011, were obtained from the Finnish Patient Insurance Centre registry. Two senior otolaryngologists analysed and evaluated the injury mechanisms. Main outcome measures: Analysis and classification of factors contributing to patient injuries. Results: During the ten-year study period, there were 67 patient injuries in operative rhinology, comprising 36% of all patient injuries in otorhinolaryngologic surgery. The majority (78%) of patients were treated in university or central hospitals and almost all (90%) by fully trained otolaryngology specialists. The factors contributing to the injuries were errors in surgical technique, like lesions to the orbit, skull base and meninges, and adjacent nerves, as well as mistakes with removable packings left in situ. Nearly half of the patients had undergone endoscopic sinus surgery. One patient died because of bleeding from the intracranial artery. Fourteen patients (21%) needed a re-operation due to the injury. Conclusions: Patient injuries in rhinology were caused by typical complications of common operations performed by otorhinolaryngology specialists. The increased volume of endoscopic sinus surgery was evident also in patient injuries.Peer reviewe
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