1,093 research outputs found

    Konjunkturer, kriser og statsfinanser : kan stater bære sine forpliktelser?

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    Foredrag av sentralbanksjef Svein Gjedrem på Norges Handelshøyskole, fredag 24. september 2010

    Annual address 2003

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    Annual address by Governor Svein Gjedrem at the meeting of the Supervisory Council of Norges Bank on 20 February 2003.publishedVersio

    Effect Screen Erosion on Reservoir Performance

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    Master's thesis in Petroleum engineeringOil and gas are mainly produced from sandstone reservoirs, where sand production may play an important role in the whole reservoir development strategy, not only in terms of optimizing well completion, but in well rate and pressure constraints. Sand screens are a commonly used completion solution in such reservoirs, either as stand alone or in a cased hole, with or without different types of gravel pack. Sand screens are not a perfect completion, they can be damaged by a collapsed borehole, plugged by reservoir fines or be eroded by sand. The idea behind this thesis is to investigate the effects of rate constraints on reservoir performance due to erosion of sand screens in a cased hole. This is done by incorporating an analytical sand screen erosion model with a completion model in NETool and a reservoir model in ECLIPSE. Results show that gravel pack is the most suitable to protect sand screens from erosion while enabling the well to produce at high rate. Analysis have shown that under investigated conditions, gravel pack sand screens completion have highest production potential

    Breeding programs on Atlantic salmon in Norway: lessons learned

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    An early establishment of selective breeding programs on Atlantic salmon has been crucial for the success of developing efficient and sustainable salmon farming in Norway. A national selective breeding program was initiated by AKVAFORSK at the beginning of the 1970s, by collecting fertilized eggs from more than 40 Norwegian river populations. Several private selective breeding programs were also initiated in the 1970s and 1980s. While these private programs were initiated using individual selection (i.e. massselection) to genetically improve growth, the national program was designed to gradually include all economically important traits in the breeding objective (i.e. growth, age at sexual maturation, disease resistance and quality traits) using a combined family and within-family selection strategy. Independent of which selection strategy and program design used, it is important to secure and maintain a broad genetic variation in the breeding populations to maximize selection response. It has been documented that genetically improved salmon from the national selective breeding program grow twice as fast as wild Atlantic salmon and require 25 per cent less feed, while salmon representing the private breeding programs all show an intermediate growth performance. As a result of efficient dissemination of genetically improved Atlantic salmon, the Norwegian salmon farming industry has reduced its feed costs by more than US$ 230 million per year! The national selective breeding program on Atlantic salmon was commercialized into a breeding company (AquaGen) in 1992. Five years later, several private companies and the AKVAFORSK Genetics Center (AFGC) established a second breeding company (SalmoBreed) using breeding candidates from one of the private breeding programs. These two breeding companies have similar products, but different strategies on how to organize the breeding program and to disseminate the genetically improved seed to the Norwegian salmon industry. Greater competition has increased the necessity to document the genetic gain obtained from the different programs and to market the economic benefits of farming the genetically improved breeds. Both breeding companies have organized their dissemination to get a sufficient share of the economic benefits in order to sustain and improve their breeding programs

    Breeding programs on Atlantic salmon in Norway: lessons learned

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    An early establishment of selective breeding programs on Atlantic salmon has been crucial for the success of developing efficient and sustainable salmon farming in Norway. A national selective breeding program was initiated by AKVAFORSK at the beginning of the 1970s, by collecting fertilized eggs from more than 40 Norwegian river populations. Several private selective breeding programs were also initiated in the 1970s and 1980s. While these private programs were initiated using individual selection (i.e. massselection) to genetically improve growth, the national program was designed to gradually include all economically important traits in the breeding objective (i.e. growth, age at sexual maturation, disease resistance and quality traits) using a combined family and within-family selection strategy. Independent of which selection strategy and program design used, it is important to secure and maintain a broad genetic variation in the breeding populations to maximize selection response. It has been documented that genetically improved salmon from the national selective breeding program grow twice as fast as wild Atlantic salmon and require 25 per cent less feed, while salmon representing the private breeding programs all show an intermediate growth performance. As a result of efficient dissemination of genetically improved Atlantic salmon, the Norwegian salmon farming industry has reduced its feed costs by more than US$ 230 million per year! The national selective breeding program on Atlantic salmon was commercialized into a breeding company (AquaGen) in 1992. Five years later, several private companies and the AKVAFORSK Genetics Center (AFGC) established a second breeding company (SalmoBreed) using breeding candidates from one of the private breeding programs. These two breeding companies have similar products, but different strategies on how to organize the breeding program and to disseminate the genetically improved seed to the Norwegian salmon industry. Greater competition has increased the necessity to document the genetic gain obtained from the different programs and to market the economic benefits of farming the genetically improved breeds. Both breeding companies have organized their dissemination to get a sufficient share of the economic benefits in order to sustain and improve their breeding programs.Biotechnology, Genetics, Food fish, Genetic drift, Genetic diversity, Aquatic animals, DNA, Selective breeding, Breeding success, Research programmes Salmonidae

    Breeding plan for silver barb (Puntius gonionotus) in Vietnam: individual (mass) selection to improve growth rate

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    Selective breeding, Fish culture, Growth, Aquaculture techniques, Genetics, Viet Nam, Puntius gonionotus

    Plasticity in response to feed availability - does feeding regime influence the relative growth performance of domesticated, wild and hybrid Atlantic salmon Salmo salar parr?

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    Growth of farmed, wild and F1 hybrid Atlantic salmon parr, Salmo salar, was investigated under three contrasting feeding regimes in order to understand how varying levels of food availability affects relative growth. Treatments consisted of standard hatchery feeding (ad libitum), access to feed for 4h every day, and access to feed for 24h on three alternate days weekly. Mortality was low in all treatments, and food availability had no effect on survival of all groups. The offspring of farmed S. salar significantly outgrew the wild S. salar, while hybrids displayed intermediate growth. Furthermore, the relative growth differences between the farmed and wild S. salar did not change across feeding treatments, indicating a similar plasticity in response to feed availability. Although undertaken in a hatchery setting, these results suggest that food availability may not be the sole driver behind the observed reduced growth differences found between farmed and wild fishes under natural conditions

    Digestibility in selected rainbow trout families and modelling of growth from the specific intake of digestible protein

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    The experiments aimed to clarify variations in digestibility of dietary nutrients in rainbow trout. Furthermore, the objective was to study how differences in digestibility might be related to growth and feed utilisation at various growth rates. When comparing the results from the experiments it appeared that particularly protein digestibility was closely related to specific growth rate and feed conversion ratio at high growth rates. As a tool to visualise the relationship between protein digestibility and growth of rainbow trout a growth model was developed based on the specific intake of digestible protein, and general assumptions on protein content and protein retention efficiency in rainbow trout. The model indicated that increased protein digestibility only partly explained growth increase and that additional factors were important for growth increment
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