Now showing items 41-50 of 181
Cellular responses induced by environmental stress factors in Arctic Seabird chicks : Responses of the antioxidant defense system and autophagic lysosomal processes related to contaminant exposure and food restriction
(Doctoral thesis; Doktorgradsavhandling, 2011-11-29)
This PhD study has investigated how two commonly occurring environmental stress factors in the Arctic (periods with little food and exposure to halogenated organic contaminants) have had an impact on two important cellular defense mechanisms in Arctic seabirds. The antioxidant defense system and autophagic lysosomal responses in liver cells of Arctic seabird chicks have been studied. Samples ...
Post mortem proteolytic degradation of myosin heavy chain in skeletal muscle of Atlantic cod
(Doctoral thesis; Doktorgradsavhandling, 2011-01-28)
One of the most important parameters of quality regarding meat both from mammals and fish is texture. The post mortem degradation of muscle and connective tissue proteins during tenderization of meat from warm-blooded animals is unwanted in fish due to a loss of product quality. Soft fillet and gaping are common problems both in wild and farmed cod and have huge impact on the quality and the consumers’ ...
Scavenging amphipods in the high Arctic : Studies of benthic and sympagic amphipods in the genera Onisimus and Anonyx
(Doctoral thesis; Doktorgradsavhandling, 2011-05-02)
The main objective of this study was to increase our knowledge about the ecology of scavenging amphipods, particularly amphipods within the genera Onisimus and Anonyx. Specifically, the emphasis was to increase the knowledge of ice-associated (sympagic) Onisimus-species, but as these species are rather inaccessible, an approach using benthic congeners as proxies was chosen. By studying the shallow-water ...
Boundary construction in mandated science : the case of ICES' advice on fisheries management
(Doctoral thesis; Doktorgradsavhandling, 2008-11-21)
What is the relationship between science and politics? What should it be? How are their respective roles conceived and acted out in practice? Should science and politics be clearly separated? How? Are there cases in which they can be usefully mixed? What cases are those, and are there some ways of mixing that are better than others? This project explores such questions by examining relationships ...
Effects of environmental factors on migratory behaviour of northern Atlantic salmon.
(Doctoral thesis; Doktorgradsavhandling, 2010-06-04)
Over the last decades, the abundances of many Atlantic salmon populations have declined drastically both due to anthropogenic and natural factors. The period when salmon enter the sea for the first time, starting as smolts in the river and subsequently as post-smolts in the fjord, is regarded as one of most critical periods in the salmon life history. In addition, salmon can also suffer from high ...
Information in financial markets : how private information affects prices, how it can be revealed and how it may be used
(Doctoral thesis; Doktorgradsavhandling, 2008-06-06)
The literature on financial markets is vast and it is probably safe to say that all tools in the economists’ tool case have been applied to this field. In this dissertation I will present three papers that are very diverse in their approach to the subject of finance, but have an important common theme; asymmetric information and efficiency in financial markets.
The seasonal migratory behavior of sympatric anadromous Arctic charr and brown trout
(Doctoral thesis; Doktorgradsavhandling, 2013-09-20)
This thesis used acoustic and archival telemetry to study fish migrations within and between freshwater and marine habitats. The main novel finding from this thesis work is that both Arctic charr and brown trout originating from rivers without access to lakes can be found in marine waters also during winter. The physical properties of the freshwater habitat may be the main factor controlling in which ...
Hunter's behavioural responses to changes in bag size and willow grouse density : implications for management and interpretation of harvest data
(Doctoral thesis; Doktorgradsavhandling, 2012-12-19)
An important aspect of ecological research is to provide guidelines and tools to wildlife managers. The ecological feature of density dependence which shapes population responses to harvest are important for wildlife management, but monitoring practices and exploiter dynamics to the changing resources and management regimes should also be included. Bag records are often collected by wildlife managers ...
Late Weichselian to early Holocene vegetation and bird activity on Andøya, Nordland County : as evidenced primarily by macrofossils
(Doctoral thesis; Doktorgradsavhandling, 2012-10-26)
This thesis shows that Late Weichselian vegetation on Andøya may have been more diverse than previous studies have revealed. The thorough investigation of macrofossils in four parallel cores provides more reliable evidence for interpreting changes in vegetation cover than reconstructions based on a single core. The botanical macrofossils retrieved in this study largely support previous studies ...
Interactions between small rodents and their food plants in tundra habitats
(Doctoral thesis; Doktorgradsavhandling, 2012-10-19)
Small rodents are key herbivores of arctic ecosystems, where their cyclic population dynamics have important implications for vegetation dynamics. The role of vegetation for shaping small rodent population dynamics remains, however, unclear. Evaluation of this interaction has been greatly hampered by the rather fragmentary knowledge of small rodents feeding ecology, which in turn is due to methodological ...