Extraction of level density and gamma strength function from primary gamma spectra

We present a new iterative procedure to extract the level density and the gamma strength function from primary gamma spectra for energies close up to the neutron binding energy. The procedure is tested on simulated spectra and on data from the Yb-173(He-3,alpha)Yb-172 reaction.Comment: 23 pages including 1 table and 7 figure

INPUT FACTOR SUBSTITUTABILITY IN SALMON AQUACULTURE

The salmon aquaculture industry has experienced substantial expansion during the last two decades. This expansion is largely the result of increased productivity, with a complementary decrease in costs. A general reduction in production costs has been accompanied by substantial shifts in the shares of inputs. Hence, one may question whether the technology has changed so much that some input factors are no longer substitutes in production. In this study, we investigate this by estimating a translog cost function focusing on the difference between full and partial static equilibrium specifications. The results from the different specifications provide evidence of limited or zero substitution possibilities in salmon production. This implies that salmon farming today can be thought of as a converter or refinement industry where less valuable fish (the feed) are converted into higher-valued product.Resource /Energy Economics and Policy,

Faustmann in the Sea: Optimal Rotation in Aquaculture

In this article an extended version of the well-known Faustmann model is developed for solving the rotation problem in fish farming. Two particularly important aspects of the problem are emphasized: First, the possibilities for cycles in relative price relationships and second, restrictions in release time for certain species. An illustration of the model based on assumptions from salmon farming shows that the inclusion of these two features has major influences on rotation time, and hence harvest weight.Aquaculture, optimal rotation, dynamic programming, relative prices., Research Methods/ Statistical Methods, Q22,

PATTERNS IN THE RELATIVE PRICE FOR DIFFERENT SIZES OF FARMED FISH

Fish farming is a biological production process dependent upon biological and environmental conditions. These constraints imply that different fish farmers are likely to have a similar distribution of different sizes of fish over time. If there are no perfect substitutes for the different sizes of fish in the shortrun, this production cycle can cause different relative prices between the different sizes over the year. By studying prices for different sizes of salmon for the period 1992–98, we show that such patterns exist. This can have important implications when studying aquaculture industries and markets. We look closer at two issues — optimal harvesting decisions and aggregation.Resource /Energy Economics and Policy,

The Value of Information in Salmon Farming: Harvesting the Right Fish to the Right Time

Research regarding management practice in fish farming has traditionally focused on two topics: production planning and forecasting of prices. This article combine these two areas of research, and illustrate how information of price patterns can change production plans, and hence increase the value of the farm enterprise. We present a model farm and illustrate with different levels of price information how information of future prices alter the original production plan and hence create extra value for the farmer. The phrasing of the paper and the empirical application are on salmon and salmon farming, but the ideas and general results should be applicable to all farmed species.Resource /Energy Economics and Policy,

Aquaculture—Opportunities and Challenges: Special Issue Introduction

Production Economics,

The SiRi Particle-Telescope System

A silicon particle-telescope system for light-ion nuclear reactions is described. In particular, the system is designed to be optimized for level density and gamma-ray strength function measurements with the so-called Oslo method. Eight trapezoidal modules are mounted at 5 cm distance from the target, covering 8 forward angles between theta = 40 and 54 degrees. The thin front dE detectors (130 micrometer) are segmented into eight pads, determining the reaction angle for the outgoing charged ejectile. Guard rings on the thick back E detectors (1550 micrometer) guarantee low leakage current at high depletion voltage.Comment: 6 pages, 8 figure

Thermal and electromagnetic properties of 166-Er and 167-Er

The primary gamma-ray spectra of 166-Er and 167-Er are deduced from the (3-He,alpha gamma) and (3-He,3-He' gamma) reaction, respectively, enabling a simultaneous extraction of the level density and the gamma-ray strength function. Entropy, temperature and heat capacity are deduced from the level density within the micro-canonical and the canonical ensemble, displaying signals of a phase-like transition from the pair-correlated ground state to an uncorrelated state at Tc=0.5 MeV. The gamma-ray strength function displays a bump around E-gamma=3 MeV, interpreted as the pygmy resonance.Comment: 21 pages including 2 tables and 11 figure

Branding local heritage and popularising a remote past: The example of Haugesund in Western Norway

Since the national romantic era, the Haugesund region of Norway has been associated with patriotism and heroism as it is believed to be the homeland of the Viking hero Harald Fairhair, the first king of Norway. In the arrival hall at the airport outside Haugesund the passengers are today faced with the following words: “Welcome to the Homeland of the Viking Kings”. The slogan refers to official regional attraction strategies based on a late modern Viking enthusiasm, used in efforts to increase local identity, to enchant a visitor market and to brand the region, in short, to create pride and glory. In this paper, dynamics of heritage production at Haugesund are examined by emphasising how a popular and commercial past (“the experience society”) mediates public debates and conflicts, thus questioning the function experts within the field of archaeology and the cultural heritage management have in local communities

What did Remigration Mean for the Numerical Growth for the Free Church Movement in Norway in the Early Twentieth Century?

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