THE ECONOMIC STRUCTURE OF HARVESTING FOR THREE VESSEL TYPES IN THE NORWEGIAN SPRING-SPAWNING HERRING FISHERY

Norwegian spring-spawning herring (Clupea harengus) is the largest fish stock in the North Atlantic and is harvested by many nations. The introduction of new technology in the 1960s resulted in a substantial increase in the efficiency of the fishing fleet. As a consequence, the stock was fished almost to extinction by the end of the 1960s. In the 1990s, the stock showed healthy growth and Total Allowable Catch (TAC) quotas have increased. This paper adds to the understanding of the harvesting process by providing measurements of the economic structure of the harvesting technology. For this fishery, Norway receives the largest share of the internationally determined TAC quota, and thus, the focus will be to investigate the harvesting process for three vessel types in the Norwegian fishing fleet: purse seiners, trawlers, and coastal vessels. Vessel- level cost and revenue data are available annually for these vessel types for the three-year period 1994–96. Estimates of input elasticities, economies of scale, and cost elasticities for a two-output cost function are reported.Resource /Energy Economics and Policy,

A Fish Is a Fish Is a Fish? Testing for Market Linkages on the Paris Fish Market

This paper applies both the Engle-Granger and Johansen cointegration test procedures to determine the existence of market linkage among high-valued {salmon and turbot) and low-valued (cod) fish species using monthly average wholesale price data recorded on the Paris fish market. We find that the price of salmon is determined exogenously to the system of prices examined and that the market for salmon is not linked to the markets for turbot or cod.Cointegration, market linkages, salmon price, Demand and Price Analysis, Environmental Economics and Policy,

Rent dissipation and potential rents in the north sea herring fishery

The paper assesses the potential for rent generation, distinguishing between resource and intra-marginal rent, in the North Sea herring fishery. A bioeconomic model combining fish population dynamics with the economic structure of the fishery is used to generate equations to compute the different rents. A combination of biological data with vessel-level economic data for UK pelagic trawlers is employed in estimations. In order to assess the dynamics of both resource and intra-marginal rent generation, the model is evaluated under various assumptions with regard to price, cost, and discount rate. Potential total rents are measured at £90-91 million annually of which resource rent makes up about £89.0 million with intra-marginal rent measured in the order of only £2.0 million. This compares to an actual rent in 2007 estimated at £ 16.3 million. The results show that, in this fishery, rent is dissipated almost entirely due to excess effort while very little is dissipated due to suboptimal stock size

An X-ray Selected Galaxy Cluster at z=1.11 in the Rosat Deep Cluster Survey

We report the discovery of an X-ray luminous galaxy cluster at z =1.11. RDCS J0910+5422 was selected as an X-ray cluster candidate in the ROSAT Deep Cluster Survey on the basis of its spatial extent in a Rosat PSPC image. Deep optical and near-IR imaging reveal a red galaxy overdensity around the peak of the X-ray emission, with a significant excess of objects with J-K and I-K colors typical of elliptical galaxies at z ~ 1.0. Spectroscopic observations at the Keck II telescope secured 9 galaxy redshifts in the range 1.095<z<1.120 yielding a mean cluster redshift of =1.106. Eight of these galaxies lie within a 30 arcsec radius around the peak X-ray emission. A deep Chandra ACIS exposure on this field shows extended X-ray morphology and allows the X-ray spectrum of the intracluster medium to be measured. The cluster has a bolometric luminosity L_x = 2.48^{+0.33}_{-0.26} x 10^44 ergs/s, a temperature of kT = 7.2^{+2.2}_{-1.4} keV, and a mass within r = 1 Mpc of 7.0 x 10^14 M_sun (H_0=65 km/s/Mpc, Omega_m = 0.3, and Lambda = 0.7). The spatial distribution of the cluster members is elongated, which is not due to an observational selection effect, and followed by the X-ray morphology. The X-ray surface brightness profile and the spectrophotometric properties of the cluster members suggest that this is an example of a massive cluster in an advanced stage of formation with a hot ICM and an old galaxy population already in place at z > 1.Comment: 19 pages, 7 figures: Figures 1,4,6 included as separate jpg files. Accepted for publication in The Astronomical Journa

Manganese influx and expression of ZIP8 is essential in primary myoblasts and contributes to activation of SOD2 [preprint]

Trace elements such as copper (Cu), zinc (Zn), iron (Fe), and manganese (Mn) are enzyme cofactors and second messengers in cell signaling. Trace elements are emerging as key regulators of differentiation and development of mammalian tissues including blood, brain, and skeletal muscle. We previously reported an influx of Cu and dynamic expression of various metal transporters during differentiation of skeletal muscle cells. Here, we demonstrate that during differentiation of skeletal myoblasts an increase of additional trace elements such as Mn, Fe and Zn occurs. Interestingly the Mn increase is concomitant with increased Mn-dependent SOD2 levels. To better understand the Mn import pathway in skeletal muscle cells, we probed the functional relevance of the closely related proteins ZIP8 and ZIP14, which are implicated in Zn, Mn, and Fe transport. Partial depletion of ZIP8 severely impaired growth of myoblasts and led to cell death under differentiation conditions, indicating that ZIP8-mediated metal transport is essential in skeletal muscle cells. Moreover, knockdown of Zip8 impaired activity of the Mn-dependent SOD2. Growth defects were partially rescued by Mn supplementation to the medium, suggesting additional functions for ZIP8 in the skeletal muscle lineage. Knockdown of Zip14, on the other hand, had only a mild effect on myotube size, consistent with a role for ZIP14 in muscle hypertrophy. This is the first report on the functional relevance of two members of the ZIP family of metal transporters in the skeletal muscle lineage, and further supports the paradigm that trace metal transporters are critical modulators of mammalian tissue development

Vertical And Horizontal Integration In The Ugandan Fish Supply Chain: Measuring For Feedback Effects To Fishermen

The purpose of this article is to report the results of a statistical investigation of links in the fish supply chain in Uganda. We are particularly interested in the extent of ex-vessel prices impacting links downstream in the fish supply chain. We test for vertical and horizontal co-integration for five important fish species using the Johansen vector error correction model. We search for price leadership using the Toda and Yamamoto (1995) procedure to test for Granger causality. And ARIMA models are used to forecast ex-vessel prices. Our results show that ex-vessel prices are only weakly related to downstream markets

Transient Hypoxia Alters Striatal Catecholamine Metabolism in Immature Brain: An In Vivo Microdialysis Study

Microdialysis probes were inserted bilaterally into the striatum of 7-day-old rat pups (n = 30) to examine extracellular fluid levels of dopamine, its metabolites 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), and the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA). The dialysis samples were assayed by HPLC with electrochemical detection. Baseline levels, measured after a 2-h stabilization period, were as follows: dopamine, not detected; DOPAC, 617 ± 33 fmol/min; HVA, 974 ± 42 fmol/min; and 5-HIAA, 276 ± 15 fmol/min. After a 40-min baseline sampling period, 12 animals were exposed to 8% oxygen for 120 min. Hypoxia produced marked reductions in the striatal extracellular fluid levels of both dopamine metabolites ( p < 0.001 by analysis of variance) and a more gradual and less prominent reduction in 5-HIAA levels ( p < 0.02 by analysis of variance), compared with controls (n = 12) sampled in room air. In the first hour after hypoxia, DOPAC and HVA levels rose quickly, whereas 5-HIAA levels remained suppressed. The magnitude of depolarization-evoked release of dopamine (elicited by infusion of potassium or veratrine through the microdialysis probes for 20 min) was evaluated in control and hypoxic animals. Depolarization-evoked dopamine efflux was considerably higher in hypoxic pups than in controls: hypoxic (n = 7), 257 ± 32 fmol/min; control (n = 12), 75 ± 14 fmol/min ( p < 0.001 by analysis of variance). These data demonstrate that a brief exposure to moderate hypoxia markedly disrupts striatal catecholamine metabolism in the immature rodent brain.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66218/1/j.1471-4159.1990.tb01914.x.pd

A Human BRCA2 Complex Containing a Structural DNA Binding Component Influences Cell Cycle Progression

AbstractGermline mutations of the human BRCA2 gene confer susceptibility to breast cancer. Although the function of the BRCA2 protein remains to be determined, murine cells homozygous for BRCA2 inactivation display chromosomal aberrations. We have isolated a 2 MDa BRCA2-containing complex and identified a structural DNA binding component, designated as BR CA2-A ssociated F actor 35 (BRAF35). BRAF35 contains a nonspecific DNA binding HMG domain and a kinesin-like coiled coil domain. Similar to BRCA2, BRAF35 mRNA expression levels in mouse embryos are highest in proliferating tissues with high mitotic index. Strikingly, nuclear staining revealed a close association of BRAF35/BRCA2 complex with condensed chromatin coincident with histone H3 phosphorylation. Importantly, antibody microinjection experiments suggest a role for BRCA2/BRAF35 complex in modulation of cell cycle progression