Identifying relativistic effects in the light-matter interaction between a high-intensity laser pulse and a one-dimensional atomic model

Masteroppgave i fysikkPHYS399MAMN-PHY

Livsmestring, kroppsøving og mat og helse – en dokumentanalyse av livsmestring sin bevegelse i utdanningspolitiske styringsdokumenter, og livsmestring i møte med fagene kroppsøving og mat og helse på mellomtrinnet

Folkehelse og livsmestring er et av de nye tverrfaglige temaene som er innført i Læreplanverket for Kunnskapsløftet av 2020 (LK20). Det pågår en debatt om hva livsmestring vil si innenfor dette temaet. Som følge av dette, kan det oppstå utfordringer for lærere i skolen om hvordan livsmestring skal belyses i undervisningen. Denne studiens mål er å bidra med å tette kunnskapshull knyttet til hvordan man kan se arbeidet med livsmestring i kroppsøving, på tvers av fagene kroppsøving og mat og helse. I denne masteroppgaven er det gjennomført en dokumentanalyse av utdanningspolitiske styringsdokumenter som henger sammen i en dokumentkjede. Dette er dokumentene som dannet grunnlaget for fagfornyelsen, og som vi ser igjen som LK20. I dokumentkjeden er NOU 2014:7 Elevenes læring i fremtidens skole, NOU 2015:8 Fremtidens skole, Meld. St. 28 Fag, fordypning, forståelse og LK20. Det blir i analysen sett på hvordan livsmestring etablerte seg som et begrep i det tverrfaglige temaet folkehelse og livsmestring i LK20. Med utgangspunkt i analysen og tekstkorpus, blir også meningsbærende tekster definert og satt opp mot min egen oppfatning av livsmestring i det tverrfaglige temaet i LK20. Analysen av dokumentkjeden viser at livsmestring blir bredt beskrevet. Livsmestring som begrep beskrives først i NOU 2015:8 som del av det flerfaglige temaet folkehelse og livsmestring, og er inspirasjonen NOU 2014:7 knyttet til Health and Wellbeing i den skotske læreplanen for grunnskolen. Beskrivelsen i NOU 2015:8, er i særlig grad rettet mot de praktisk-estetiske fagene. I Meld. St. 28 ser man livsmestring som del av det tverrfaglige temaet folkehelse og livsmestring, som forblir i LK20. I LK20 skal folkehelse og livsmestring blant annet bidra til at elevene skal utvikle kompetanse til å ta ansvarlige livsvalg for blant annet den fysiske og psykiske helsen. Beskrivelsene av livsmestring drøftes opp mot teori og gjennomført litteraturgjennomgang, i nasjonal og internasjonal kontekst. Sentrale temaer som drøftes opp mot begrepet livsmestring, er velværekompetanse, dybdelæring, dybdelæring i fagene kroppsøving og mat og helse, danning, mestring, og kritisk tenkning. Dette ses i lys av blant annet teori knyttet til kroppssyn, mestring og filosofiens tanker om valg og mening med livet. Det oppfattes blant annet at dybdelæring er en sentral del av livsmestring da beskrivelsene av de tverrfaglige temaene og dybdelæring er tilnærmet like. Med bakgrunn i dokumentanalysen og meningsbærende tekster, oppfattes det i denne studien at III bakgrunnen for livsmestring, slik Ludvigsenutvalget ønsket, ikke er kommet like tydelig frem i LK20

Phenology of deer ked (Lipoptena cervi) host-seeking flight activity and its relationship with prevailing autumn weather

Background: The deer ked (Lipoptena cervi) is an ectoparasite on cervids that has invaded large parts of Norway, Sweden and Finland during recent decades. During their host-seeking flight activity, the adult deer keds constitute a considerable nuisance to people and limit human outdoor recreation. The bites of the deer ked can cause long-lasting dermatitis in humans. Determining the pattern of flight activity during autumn is hence important. Methods: Data on flight phenology was gathered by walking along transects in the forest in two counties of Norway during 2009–2013, counting the number of host-seeking keds. We analysed how the flight activity of deer keds varied depending on date and prevailing weather during autumn. Results: The best model of flight activity included both date and temperature, both as nonlinear terms. Host-seeking deer keds were observed from early August to mid-November with a marked peak in late September. Number of host-seeking keds declined with temperatures falling below the mean, but did not increase much at above mean temperatures. The pattern of flight phenology was similar across the two counties and five years. Conclusions: Parasitic arthropods may be strongly affected by prevailing weather during off-host periods. Our study shows an estimated positive effect of temperature on deer ked flight activity mainly for below mean temperatures in late autumn, while the effect of temperature on flight activity in early autumn was weak. The pattern of host-seeking flight activity during late, rather than early autumn, is hence more likely to change with ongoing climate change, with a predicted increase in duration of the host-seeking period. Keywords: Deer ked, Invading parasites, Climate, Temperature, Moose, Phenolog

How general are generalist parasites? The small mammal part of the Lyme disease transmission cycle in two ecosystems in northern Europe

The pathogens causing Lyme disease are all vectored by generalist tick species found on a wide range of vertebrates, but spatial and annual variation in host use has rarely been quantified. We here compare the load of Ixodes ricinus (the vector) on small mammals and investigate the infection prevalence of Borrelia burgdorferi s.l. (the pathogen) involved in the enzootic transmission cycle of Lyme disease in two contrasting ecosystems in Norway from 2014 to 2016. The most common larval tick host in the eastern region was the bank vole, while the common shrew dominated in the western region of Norway. However, the wood mouse and the bank vole had consistently higher larval tick loads than the common shrew in both ecosystems. Hence, the evidence indicated that species are differently suitable as hosts, regardless of their abundances. The pathogen infection prevalence was similar among small mammal species, but markedly higher in the region with larger small mammal populations and higher tick loads, while the seasonal and annual variation was less marked. Our study indicated that the generalist I. ricinus shows consistent patterns of load on species of small vertebrate hosts, while B. burgdorferi s.l. (B. afzelii) was a true generalist. The similar roles of host species across regions suggest that disease dynamics can be predicted from host community composition, but predicting the role of host community composition for disease dynamics requires a detailed understanding of the different species population limitations under global change

How general are generalist parasites? The small mammal part of the Lyme disease transmission cycle in two ecosystems in northern Europe

The pathogens causing Lyme disease are all vectored by generalist tick species found on a wide range of vertebrates, but spatial and annual variation in host use has rarely been quantified. We here compare the load of Ixodes ricinus (the vector) on small mammals and investigate the infection prevalence of Borrelia burgdorferi s.l. (the pathogen) involved in the enzootic transmission cycle of Lyme disease in two contrasting ecosystems in Norway from 2014 to 2016. The most common larval tick host in the eastern region was the bank vole, while the common shrew dominated in the western region of Norway. However, the wood mouse and the bank vole had consistently higher larval tick loads than the common shrew in both ecosystems. Hence, the evidence indicated that species are differently suitable as hosts, regardless of their abundances. The pathogen infection prevalence was similar among small mammal species, but markedly higher in the region with larger small mammal populations and higher tick loads, while the seasonal and annual variation was less marked. Our study indicated that the generalist I. ricinus shows consistent patterns of load on species of small vertebrate hosts, while B. burgdorferi s.l. (B. afzelii) was a true generalist. The similar roles of host species across regions suggest that disease dynamics can be predicted from host community composition, but predicting the role of host community composition for disease dynamics requires a detailed understanding of the different species population limitations under global change

Data from: Genetic and morphometric divergence in threespine stickleback in the Chignik catchment, Alaska

Divergent selection pressures induced by different environmental conditions typically lead to variation in life history, behaviour and morphology. When populations are locally adapted to their current environment, selection may limit movement into novel sites, leading to neutral and adaptive genetic divergence in allopatric populations. Subsequently, divergence can be reinforced by development of pre- or post-zygotic barriers to gene flow. The threespine stickleback, Gasterosteus aculeatus, is a primarily marine fish that has invaded freshwater repeatedly in postglacial times. After invasion, the established freshwater populations typically show rapid diversification of several traits as they become reproductively isolated from their ancestral marine population. In this paper we examine the genetic and morphometric differentiation between sticklebacks living in an open system comprising a brackish water lagoon, two freshwater lakes, and connecting rivers. By applying a set of microsatellite markers, we disentangled the genetic relationship of the individuals across the diverse environments and identified two genetic populations: one associated with brackish and the other with the freshwater environments. The ‘brackish’ sticklebacks were larger and had a different body shape than those in freshwater. However, we found evidence for upstream migration from the brackish lagoon into the freshwater environments, as fish that were genetically and morphometrically similar to the lagoon fish were found in all freshwater sampling sites. Regardless, few F1-hybrids were identified and it therefore appears that some pre- and/or post-zygotic barriers to gene flow rather than geographic distance are causing the divergence in this system

Chignik_sticklebacks

Microsatellite- and landmark information for Chignik Stickleback collected 200

Ecological ramifications of adaptation to size-selective mortality

Size-selective mortality due to harvesting is a threat to numerous exploited species, but how it affects the ecosystem remains largely unexplored. Here, we used a pond mesocosm experiment to assess how evolutionary responses to opposite size-selective mortality interacted with the environment (fish density and light intensity used as a proxy of resource availability) to modulate fish populations, prey community composition and ecosystem functions. We used medaka (Oryzias latipes) previously selected over 10 generations for small size (harvest-like selection; small-breeder line) or large size (large-breeder line), which displayed slow somatic growth and early maturity or fast somatic growth and late maturity, respectively. Large-breeder medaka produced more juveniles, which seemed to grow faster than small-breeder ones but only under high fish density. Additionally, large-breeder medaka had an increased impact on some benthic prey, suggesting expanded diet breadth and/or enhanced foraging abilities. As a consequence, increased light stimulated benthic algae biomass only in presence of large-breeder medaka, which were presumably better at controlling benthic grazers. Aggregated effect sizes at the community and ecosystem levels revealed that the ecological effects of medaka evolution were of similar magnitude to those induced by the environment and fish introduction. These findings indicate the important environmental dependency of evolutionary response to opposite size-selective mortality on higher levels of biological organizations