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  • 1
    Publication Date: 2017-01-05
    Description: We consider the optimal harvesting problem for a fish farmer in a model that accounts for stochastic prices featuring Schwartz (1997 ) two-factor price dynamics. Unlike any other literature in this context, we take account of the existence of a newly-established market in salmon futures, which determines risk premia and other relevant variables, that influence risk-averse fish farmers in their harvesting decision. We consider the cases of single and infinite rotations. The value function of the harvesting problem determined in our arbitrage-free setup constitutes the fair values of lease and ownership of the fish farm when correctly accounting for price risk. The data set used for this analysis contains a large set of futures contracts with different maturities traded at the Fish Pool market between June 12, 2006 and March 22, 2012. We assess the optimal strategy, harvesting time, and value against two alternative setups. The first alternative involves simple strategies that lack managerial flexibility; the second alternative allows for managerial flexibility and risk aversion as modeled by a constant relative risk aversion utility function, but without access to the salmon futures market. In both cases, the loss in project value can be very significant, and in the second case is only negligible for extremely low levels of risk aversion. As a consequence, for a risk-averse fish farmer, the presence of a salmon futures market as well as managerial flexibility are highly important.
    Keywords: G13 - Contingent Pricing ; Futures Pricing, Q20 - General, Q22 - Fishery ; Aquaculture
    Print ISSN: 0002-9092
    Electronic ISSN: 1467-8276
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
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  • 2
    Publication Date: 2017-01-05
    Description: Natural resource managers typically adopt precautionary quota buffers to account for scientific and management uncertainty. Such buffers ensure compliance with harvest targets up to a confidence level set by the manager, but represent foregone profits and create incentives for firms’ voluntary investment in the provision of information that lessens the regulator’s uncertainty. This paper characterizes conditions under which the fishing industry would willingly upgrade its reporting technology to provide accurate and timely catch data. Wireless technologies currently available to harvesters make the provision of real-time information feasible and affordable. Industry’s incentives critically depend on the manager’s expected choice of effort restrictions under the alternative technologies. Upgrading is attractive if the new distribution of reporting error shifts probability mass away from large errors so that the quantile at the confidence level is reduced. First-order stochastic dominance by the distribution under the baseline technology is a sufficient condition. Evidence from the Maryland Blue Crab Accountability Pilot Program, an industry-led initiative that tested the feasibility of adopting e-logbooks, illustrates the results. Real-time availability of accurate catch information under electronic reporting would translate into in-season adjustments of the manager’s controls that could increase the industry’s total harvest.
    Keywords: D80 - General, D81 - Criteria for Decision-Making under Risk and Uncertainty, Q22 - Fishery ; Aquaculture
    Print ISSN: 0002-9092
    Electronic ISSN: 1467-8276
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
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  • 3
    Publication Date: 2017-01-13
    Description: Earlier, vitamin C was demonstrated to sterilize Mycobacterium tuberculosis culture via Fenton's reaction at high concentration. It alters the regulatory pathways associated with stress response and dormancy. Since (p)ppGpp is considered to be the master regulator of stress response and is responsible for bacterial survival under stress, we tested the effect of vitamin C on the formation of (p)ppGpp. In vivo estimation of (p)ppGpp showed a decrease in (p)ppGpp levels in vitamin C-treated M. smegmatis cells in comparison to the untreated cells. Furthermore, in vitro (p)ppGpp synthesis using Rel MSM enzyme was conducted in order to confirm the specificity of the inhibition in the presence of variable concentrations of vitamin C. We observed that vitamin C at high concentration can inhibit the synthesis of (p)ppGpp. We illustrated binding of vitamin C to Rel MSM by isothermal titration calorimetry. Enzyme kinetics was followed where K 0.5 was found to be increased with the concomitant reduction of V max value suggesting mixed inhibition. Both long-term survival and biofilm formation were inhibited by vitamin C. The experiments suggest that vitamin C has the potential to be developed as the inhibitor of (p)ppGpp synthesis and stress response, at least in the concentration range used here.
    Keywords: Physiology & Biochemistry
    Print ISSN: 0378-1097
    Electronic ISSN: 1574-6968
    Topics: Biology
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  • 4
    Publication Date: 2017-01-05
    Description: This article offers a theoretical analysis of the impact that the introduction of aquaculture has on wild fish stocks and consumer utility, taking into account three key components: (1) the dependence of aquaculture on reduction fisheries for the feeding of the farmed species; (2) biological interactions between the wild edible species—the predator—and the wild feed species—the prey; and (3) consumer preferences for wild and farmed fish. Fisheries are in open access, while the aquaculture sector is competitive. We show that when biological interactions are moderate, the introduction of aquaculture is beneficial in the long run: it improves consumer utility and alleviates the pressure on the edible fish stock. Results are deeply modified when biological interactions are strong: the stock of edible wild fish is reduced and the introduction of aquaculture may even cause a decrease in consumer utility. We then explore the consequences of improving aquaculture efficiency and the sensitivity of consumer preferences to the farmed fish characteristics, in the case where biological interactions are absent. Lastly, we analyze how our outcomes on the entry of aquaculture are affected when the wild edible fishery is optimally regulated, in combination with different assumptions on the regulation of the feed fishery. Results are again conditional on the intensity of biological interactions.
    Keywords: Q22 - Fishery ; Aquaculture
    Print ISSN: 0002-9092
    Electronic ISSN: 1467-8276
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Economics
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  • 5
    Publication Date: 2017-01-19
    Description: Although nitric oxide (NO) is an important signaling molecule in bacteria and higher organisms, excessive intracellular NO is highly reactive and dangerous. Therefore, living cells need strict regulation systems for cellular NO homeostasis. Recently, we discovered that Streptomyces coelicolor A3(2) retains the nitrogen oxide cycle (NO 3 – -〉NO 2 – -〉NO-〉NO 3 – ) and nitrite removal system. The nitrogen oxide cycle regulates cellular NO levels, thereby controlling secondary metabolism initiation (red-pigmented antibiotic, RED production) and morphological differentiation. Nitrite induces gene expression in neighboring cells, suggesting another role for this cycle as a producer of transmittable intercellular communication molecules. Here, we demonstrated that ammonium-producing nitrite reductase (NirBD) is involved in regulating NO homeostasis in S. coelicolor A3(2). NirBD was constitutively produced in culture independently of GlnR, a known transcriptional factor. NirBD cleared the accumulated nitrite from the medium. Nir deletion mutants showed increased NO-dependent gene expression at later culture stages, whereas the wild-type M145 showed decreased expression, suggesting that high NO concentration was maintained in the mutant. Moreover, the nir deletion mutant produced more RED than that produced by the wild-type M145. These results suggest that NO 2 – removal by NirBD is important to regulate NO homeostasis and to complete NO signaling in S. coelicolor .
    Keywords: Physiology & Biochemistry
    Print ISSN: 0378-1097
    Electronic ISSN: 1574-6968
    Topics: Biology
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