Switching Costs in the Norwegian Banking Sector

MasteroppgaveECON391MASV-SØKPROF-SØ

Refugia of marine fish in the northeast Atlantic during the last glacial maximum: concordant assessment from archaeozoology and palaeotemperature reconstructions

Archaeozoological finds of the remains of marine and amphihaline fish from the Last Glacial Maximum (LGM) ca. 21 ka ago show evidence of very different species ranges compared to the present. We have shown how an ecological niche model (ENM) based on palaeoclimatic reconstructions of sea surface temperature and bathymetry can be used to effectively predict the spatial range of marine fish during the LGM. The results indicate that the ranges of marine fish species now in northwestern Europe were displaced significantly southwards from the modern distribution, challenging an existing paradigm of marine glacial refugia. The model presents strong evidence that there was an invasion of important fish through the Straits of Gibraltar in glacial times, where they were exploited by Palaeolithic human populations around the western Mediterranean Sea. The ENM results are important for ongoing studies of molecular ecology that aim to assess marine glacial refugia from the genetic structure of living populations, and they pose questions about the genetic identity of vanished marine populations during the LGM. Economically, the approach may be used to understand how the ranges of exploited fish species may be displaced with the future climate warming. The research presents a challenge for future archaeozoological work to delimit the glacial refugia and to verify palaeoclimatic reconstructions based on deep-sea core record

Reggaebass : En analyse av basspillet på albumet Legend

Masteroppgave rytmisk musikk MUR500 - Universitetet i Agder 201

The Chromosome-Level Genome Assembly of European Grayling Reveals Aspects of a Unique Genome Evolution Process Within Salmonids

Salmonids represent an intriguing taxonomical group for investigating genome evolution in vertebrates due to their relatively recent last common whole genome duplication event, which occurred between 80 and 100 million years ago. Here, we report on the chromosome-level genome assembly of European grayling (Thymallus thymallus), which represents one of the earliest diverged salmonid subfamilies. To achieve this, we first generated relatively long genomic scaffolds by using a previously published draft genome assembly along with long-read sequencing data and a linkage map. We then merged those scaffolds by applying synteny evidence from the Atlantic salmon (Salmo salar) genome. Comparisons of the European grayling genome assembly to the genomes of Atlantic salmon and Northern pike (Esox lucius), the latter used as a nonduplicated outgroup, detailed aspects of the characteristic chromosome evolution process that has taken place in European grayling. While Atlantic salmon and other salmonid genomes are portrayed by the typical occurrence of numerous chromosomal fusions, European grayling chromosomes were confirmed to be fusion-free and were characterized by a relatively large proportion of paracentric and pericentric inversions. We further reported on transposable elements specific to either the European grayling or Atlantic salmon genome, on the male-specific sdY gene in the European grayling chromosome 11A, and on regions under residual tetrasomy in the homeologous European grayling chromosome pairs 9A-9B and 25A-25B. The same chromosome pairs have been observed under residual tetrasomy in Atlantic salmon and in other salmonids, suggesting that this feature has been conserved since the subfamily split.Peer reviewe

Tailoring the properties of a-site substituted Ba1-xGd0.8La0.2+xCo2O6-δ

The double perovskite BaGd0.8La0.2Co2O6-δ (BGLC) shows excellent performance as oxygen electrode for Proton Ceramic Fuel Cells (PCFCs) and electrolyzer cells (PCEC), with polarization resistances in wet oxygen of 0.04 and 10 Ωcm2 at 650 and 350 ⁰C, respectively [1]. Compared with other reported PCFC cathodes [2], BGLC performs better both at high and low temperature. The excellent performance of BGLC in proton ceramic cells is rationalized by a suggested partial proton conductivity at intermediate temperatures, supported by significant hydration up to 400°C observed by thermogravimetric studies. However, the chemical stability of BGLC in high steam pressures under PCEC operation remains a concern due to its highly basic A-site. Thus, tailoring the A-site stoichiometry by partial substitution of Ba with La may be a viable route for further optimizing the balance between chemical stability and electrochemical performance. In the literature we find numerous defect chemical models describing REBaCo2O5.5+δ-type double perovskites, but these are typically limited to describing the oxygen non-stoichiometry. Little can be found which relates defect chemistry to electrochemical performance, electrical conductivity or hydration behavior. Thus, this contribution aims to develop a global defect chemical model of the system Ba1‑xGd0.8La0.2+xCo2O6-δ (x = 0-0.5) by investigating its structural and functional properties as a function of Ba-site substitution. The complex structural behavior of Ba-site substituted BGLC is elucidated by combining synchrotron and neutron diffraction data with high temperature XRD to describe the local Co-O environment and the degree of cation and anion ordering as a function of temperature and pO2. The implications of A-site stoichiometry on proton incorporation are further investigated by thermogravimetric hydration studies supported by neutron powder diffraction of dry and deuterated samples. Finally, these properties are linked to oxygen non-stoichiometry, electrical conductivity and electrochemical performance to develop and validate our general defect chemical model for the system Ba1‑xGd0.8La0.2+xCo2O6-δ (x = 0-0.5). Please click Additional Files below to see the full abstract

Cross-species amplification of 36 cyprinid microsatellite loci in Phoxinus phoxinus (L.) and Scardinius erythrophthalmus (L.)

<p>Abstract</p> <p>Background</p> <p>To conduct phylogeographic or population genetic studies, an adequate number of DNA markers for the focal species are required. Due to severe unavailability of genotype markers of any kind for the species Eurasian minnow (<it>Phoxinus phoxinus </it>L.) and rudd (<it>Scardinius erythrophthalmus </it>L.), we set out to attempt cross-amplification of a set of microsatellite loci from related species.</p> <p>Findings</p> <p>We tested 36 cyprinid microsatellite loci for cross-species amplification in minnow and rudd. Fifteen species-locus combinations produced amplifications in minnow, seven being polymorphic, while 18 combinations amplified in rudd, nine of these being polymorphic.</p> <p>Conclusions</p> <p>The positive cross-species amplifications present potential contributions to the establishment of genetic marker sets for population genetics studies of the two focal species.</p

Contemporary divergence in early life history in grayling (Thymallus thymallus)

<p>Abstract</p> <p>Background</p> <p>Following colonization of new habitats and subsequent selection, adaptation to environmental conditions might be expected to be rapid. In a mountain lake in Norway, Lesjaskogsvatnet, more than 20 distinct spawning demes of grayling have been established since the lake was colonized, some 20-25 generations ago. The demes spawn in tributaries consistently exhibiting either colder or warmer temperature conditions during spawning in spring and subsequent early development during early summer. In order to explore the degree of temperature-related divergence in early development, a multi-temperature common-garden experiment was performed on embryos from four different demes experiencing different spring temperatures.</p> <p>Results</p> <p>Early developmental characters were measured to test if individuals from the four demes respond differently to the treatment temperatures. There was clear evidence of among-deme differences (genotype - environment interactions) in larval growth and yolk-to-body-size conversion efficiency. Under the cold treatment regime, larval growth rates were highest for individuals belonging to cold streams. Individuals from warm streams had the highest yolk-consumption rate under cold conditions. As a consequence, yolk-to-body-mass conversion efficiency was highest for cold-deme individuals under cold conditions. As we observed response parallelism between individuals from demes belonging to similar thermal groups for these traits, some of the differentiation seems likely to result from local adaptation</p> <p>Conclusion</p> <p>The observed differences in length at age during early larval development most likely have a genetic component, even though both directional and random processes are likely to have influenced evolutionary change in the demes under study.</p

Rapid recovery of normal gill morphology and blood physiology in brown trout (Salmo trutta) after short-term exposure to toxic concentrations of aqueous aluminium under non-steady state chemical conditions

Freshwater acidification is characterised by elevated concentrations of aqueous aluminium. Global emissions of acidifying agents are reduced due to international agreements, and freshwater acidification has shifted from chronic to a more episodic character. The recovery of fish populations in acidified areas is likely to depend on the individual’s ability to recover from short-time aluminium exposures. We exposed brown trout (Salmo trutta) to an Al-rich medium, nominal concentration 600 µg L–1, for 0.5, 2, 6, 8 and 11 hours, before transfer to circumneutral Al-poor water for recovery. As controls, fish were either exposed for 11 hours to an acidified Al-poor medium or to untreated water. Some mortality during the first 24 hours of the recovery period occurred in fish exposed for 11, 8 and 6 hours to aluminium. No mortality during recovery was observed in the remaining groups. Aluminium exposure led to increased haematocrit and plasma lactate concentration, decreased plasma chloride concentration, deposition of aluminium on gill surfaces, and morphological alteration of the gill structures. The responses depended on exposure time. Aluminium deposited on the gill disappeared and plasma lactate levels were at control levels after 1 day in the recovery water, while haematocrit and plasma chloride levels were at control levels after 14 days of recovery. Gills in fish exposed to aluminium for 11 hours were almost fully recovered after 14 days. We conclude that the toxic response in brown trout exposed to an acutely toxic aluminium challenge is reversible. Moreover, the first 24 hours after aluminium exposures is the most critical period for the fish recovery. Further, it takes no more than 14 days for brown trout to fully recover from an acute toxic aluminium exposure, and only 1 day if the aluminium challenge is moderate.publishedVersio

Contemporary temperature-driven divergence in a Nordic freshwater fish under conditions commonly thought to hinder adaptation

BACKGROUND: Evaluating the limits of adaptation to temperature is important given the IPCC-predicted rise in global temperatures. The rate and scope of evolutionary adaptation can be limited by low genetic diversity, gene flow, and costs associated with adaptive change. Freshwater organisms are physically confined to lakes and rivers, and must therefore deal directly with climate variation and change. In this study, we take advantage of a system characterised by low genetic variation, small population size, gene flow and between-trait trade-offs to study how such conditions affect the ability of a freshwater fish to adapt to climate change. We test for genetically-based differences in developmental traits indicating local adaptation, by conducting a common-garden experiment using embryos and larvae from replicate pairs of sympatric grayling demes that spawn and develop in natural cold and warm water, respectively. These demes have common ancestors from a colonization event 22 generations ago. Consequently, we explore if diversification may occur under severely constraining conditions. RESULTS: We found evidence for divergence in ontogenetic rates. The divergence pattern followed adaptation predictions as cold-deme individuals displayed higher growth rates and yolk conversion efficiency than warm-deme individuals at the same temperature. The cold-deme embryos had a higher rate of muscle mass development. Most of the growth- and development differences occurred prior to hatch. The divergence was probably not caused by genetic drift as there was a strong degree of parallelism in the divergence pattern and because phenotypic differentiation (Q(ST)) was larger than estimated genetic drift levels (microsatellite F(ST)) between demes from different temperature groups. We also document that these particular grayling populations cannot develop successfully at temperatures above 12°C, whereas other European populations can, and that increasing the muscle mass development rate comes at the cost of some skeletal trait development rates. CONCLUSIONS: This study shows that genetically based phenotypic divergence can prevail even under conditions of low genetic variation and ongoing gene flow. Furthermore, population-specific maximum development temperatures along with musculoskeletal developmental trade-offs may constrain adaptation