On the ecology of cold-water phytoplankton in the Baltic Sea

Increased anthropogenic loading of nitrogen (N) and phosphorus (P) has led to an eutrophication problem in the Baltic Sea, and the spring bloom is a key component in the biological uptake of increased nutrient concentrations. The spring bloom in the Baltic Sea is dominated by both diatoms and dinoflagellates. However, the sedimentation of these groups is different: diatoms tend to sink to the sea floor at the end of the bloom, while dinoflagellates to a large degree are been remineralized in the euphotic zone. Understanding phytoplankton competition and species specific ecological strategies is thus of importance for assessing indirect effects of phytoplankton community composition on eutrophication problems. The main objective of this thesis was to describe some basic physiological and ecological characteristics of the main cold-water diatoms and dinoflagellates in the Baltic Sea. This was achieved by specific studies of: (1) seasonal vertical positioning, (2) dinoflagellate life cycle, (3) mixotrophy, (4) primary production, respiration and growth and (5) diatom silicate uptake, using cultures of common cold-water diatoms: Chaetoceros wighamii, C. gracilis, Pauliella taeniata, Thalassiosira baltica, T. levanderi, Melosira arctica, Diatoma tenuis, Nitzschia frigida, and dinoflagellates: Peridiniella catenata, Woloszynskia halophila and Scrippsiella hangoei. The diatoms had higher primary production capacity and lower respiration rate compared with the dinoflagellates. This difference was reflected in the maximum growth rate, which for the examined diatoms range from 0.6 to 1.2 divisions d-1, compared with 0.2 to 0.3 divisions d-1 for the dinoflagellates. Among diatoms there were species specific differences in light utilization and uptake of silicate, and C. wighamii had the highest carbon assimilation capacity and maximum silicate uptake. The physiological properties of diatoms and dinoflagellates were used in a model of the onset of the spring bloom: for the diatoms the model could predict the initiation of the spring bloom; S. hangoei, on the other hand, could not compete successfully and did not obtain positive growth in the model. The other dinoflagellates did not have higher growth rates or carbon assimilation rates and would thus probably not perform better than S. hangoei in the model. The dinoflagellates do, however, have competitive advantages that were not included in the model: motility and mixotrophy. Previous investigations has revealed that the chain-forming P. catenata performs diurnal vertical migration (DVM), and the results presented here suggest that active positioning in the water column, in addition to DVM, is a key element in this species' life strategy. There was indication of mixotrophy in S. hangoei, as it produced and excreted the enzyme leucine aminopeptidase (LAP). Moreover, there was indirect evidence that W. halophila obtains carbon from other sources than photosynthesis when comparing increase in cell numbers with in situ carbon assimilation rates. The results indicate that mixotrophy is a part of the strategy of vernal dinoflagellates in the Baltic Sea. There were also indications that the seeding of the spring bloom is very important for the dinoflagellates to succeed. In mesocosm experiments dinoflagellates could not compete with diatoms when their initial numbers were low. In conclusion, this thesis has provided new information about the basic physiological and ecological properties of the main cold-water phytoplankton in the Baltic Sea. The main phytoplankton groups, diatoms and dinoflagellates, have different physiological properties, which clearly separate their life strategies. The information presented here could serve as further steps towards better prognostic models of the effects of eutrophication in the Baltic Sea.Övergödningen av Östersjön är ett välkänt problem som förorsakas av mänskligt utsläpp av kväve och fosfor. Många av dessa näringsämnen blir tagna upp av algerna under våren när ljusets ökade intensitet sätter igång en vårblomning hos algerna. Därför är kunskap om algernas växt under denna period viktig för förståelsen av eutrofieringsprocesser i Östersjön. Målsättningen av denna avhandling var att beskriva grundläggande fysiologiska och ekologiska egenskaper hos alger som är vanliga under vårblomningen i Östersjön. Detta mål uppnåddes genom specifika studier av (1) långskiktig vertikal placering (2) dinoflagellateers livscykler (3) mixotrofi (4) primärproduktion, respiration och tillväxt och (5) kiselalgers silikatupptag. Arbetet blev utfört i havet utanför Hangö och med laboratoriekulturer av kiselalgerna: Chaetoceros wighamii, C. gracilis, Pauliella taeniata, Thalassiosira baltica, T. levanderi, Melosira arctica, Diatoma tenuis, Nitzschia frigida, och dinoflagellaterna: Peridiniella catenata, Woloszynskia halophila and Scrippsiella hangoei. Kiselalgerna hade högre primär produktion och lägre respiration än dinoflagellaterna. Denna skillnad reflekterades också i den maximala tillväxthastigheten som för kiselalgerna var 0.6-1.2 delningar per dag och för dinoflagellaterna 0.2-0.3 delningar per dag. Bland kiselalgerna var det också arts specifika skillnader i användandet av ljus och upptagandet av silikat. C. wighamii hade den högsta primärproduktionen, silikatupptag och maximal tillväxthastighet. De fysiologiska egenskaperna hos kiselalgerna och dinoflagellaterna blev använda i en modell av tidpunkten för vårblomningen. För kiselalgerna kunde modellen förutspå vårblomingens början men dinoflagellaterna fick inte positiv växt i modellen. Dessa arter finns i Östersjön under våren och måste därför ha andra konkurrensegenskaper som inte var med i modellen så som mobilitet och mixotrofi (förmågan till att uppta näring i organisk form). Den kolonibildande dinoflagellaten P. catenata är en god simmare, och resultaten indikerar att aktiv positionering i vattenpelaren är viktigt för denna arts ekologiska strategi. Det var bevis för mixotrfi i S. hangoei eftersom arten producerar enzymet leucine aminopeptidase (LAP). Det var också resultat som indirekt pekade mot mixtotrofi hos W. halophila eftersom tillväxten var mycket högre än fixeringsraten av karbon indikerade. Det ursprungliga antal dinoflagellater verkar också vara mycket viktig för den biomassa som byggs upp under vårblomningen. Denna avhandling har beskrivit ny information om fysiologiska och ekologiska egenskaper hos algerna som är vanliga under vårblomningen i Östersjön. Detta är information som inte tidigare har funnits på artnivå

Entreprenørskap i utdanningen - perspektiver og begreper

Formålet med denne rapporten er å gjennomgå teorigrunnlaget for entreprenørskap i utdanningen (EiU) og drøfte hvordan det kan operasjonaliseres med hensyn til utforming av utdanningstilbud i entreprenørskap på ulike nivåer og på ulike fagområder i utdanningssystemet

Fellespotten i Regionale forskningsfond – status og utviklingsmuligheter

I denne rapporten presenteres en analyse av den såkalte fellespotten i Regionale forsk-ningsfond. Fellespotten utgjør 15 prosent av de midlene som årlig bevilges til Regionale Forskningsfond, og skal brukes til felles utlysninger i samarbeid mellom regionene for å stimulere til felles satsinger. Formålet med analysen er å gjennomføre en evaluering av ordningen og fremme forslag om videre utvikling av den

White matter lesions characterise brain involvement in moderate to severe chronic obstructive pulmonary disease, but cerebral atrophy does not.

BACKGROUND: Brain pathology is relatively unexplored in chronic obstructive pulmonary disease (COPD). This study is a comprehensive investigation of grey matter (GM) and white matter (WM) changes and how these relate to disease severity and cognitive function. METHODS: T1-weighted and fluid-attenuated inversion recovery images were acquired for 31 stable COPD patients (FEV1 52.1% pred., PaO2 10.1 kPa) and 24 age, gender-matched controls. T1-weighted images were segmented into GM, WM and cerebrospinal fluid (CSF) tissue classes using a semi-automated procedure optimised for use with this cohort. This procedure allows, cohort-specific anatomical features to be captured, white matter lesions (WMLs) to be identified and includes a tissue repair step to correct for misclassification caused by WMLs. Tissue volumes and cortical thickness were calculated from the resulting segmentations. Additionally, a fully-automated pipeline was used to calculate localised cortical surface and gyrification. WM and GM tissue volumes, the tissue volume ratio (indicator of atrophy), average cortical thickness, and the number, size, and volume of white matter lesions (WMLs) were analysed across the whole-brain and regionally - for each anatomical lobe and the deep-GM. The hippocampus was investigated as a region-of-interest. Localised (voxel-wise and vertex-wise) variations in cortical gyrification, GM density and cortical thickness, were also investigated. Statistical models controlling for age and gender were used to test for between-group differences and within-group correlations. Robust statistical approaches ensured the family-wise error rate was controlled in regional and local analyses. RESULTS: There were no significant differences in global, regional, or local measures of GM between patients and controls, however, patients had an increased volume (p = 0.02) and size (p = 0.04) of WMLs. In patients, greater normalised hippocampal volume positively correlated with exacerbation frequency (p = 0.04), and greater WML volume was associated with worse episodic memory (p = 0.05). A negative relationship between WML and FEV1 % pred. approached significance (p = 0.06). CONCLUSIONS: There was no evidence of cerebral atrophy within this cohort of stable COPD patients, with moderate airflow obstruction. However, there were indications of WM damage consistent with an ischaemic pathology. It cannot be concluded whether this represents a specific COPD, or smoking-related, effect

Evaluering av NTNU Technology Transfer

Med dette presenteres resultatene fra en evaluering av NTNU Technology Transfer AS (TTO), som er gjennomført på oppdrag av NTNU. Utgangspunktet for oppdraget, var NTNUs ønske om å få en helhetlig analyse av TTOs rolle innenfor NTNUs strategi for nyskaping, og som kunne brukes i en pågående prosess med videreutvikling av denne strategien. Av denne grunn er det lagt vekt på å diskutere hvilke muligheter det er for å utvikle aktiviteten i TTO, både ved en bedre tilrettelegging av rammebetingelsene for virksomheten, og ved en utvikling av virksomhetens strategi

Quasi-diffusion magnetic resonance imaging (QDI): A fast, high b-value diffusion imaging technique.

To enable application of non-Gaussian diffusion magnetic resonance imaging (dMRI) techniques in large-scale clinical trials and facilitate translation to clinical practice there is a requirement for fast, high contrast, techniques that are sensitive to changes in tissue structure which provide diagnostic signatures at the early stages of disease. Here we describe a new way to compress the acquisition of multi-shell b-value diffusion data, Quasi-Diffusion MRI (QDI), which provides a probe of subvoxel tissue complexity using short acquisition times (1-4 min). We also describe a coherent framework for multi-directional diffusion gradient acquisition and data processing that allows computation of rotationally invariant quasi-diffusion tensor imaging (QDTI) maps. QDI is a quantitative technique that is based on a special case of the Continuous Time Random Walk model of diffusion dynamics and assumes the presence of non-Gaussian diffusion properties within tissue microstructure. QDI parameterises the diffusion signal attenuation according to the rate of decay (i.e. diffusion coefficient, D in mm2 s-1) and the shape of the power law tail (i.e. the fractional exponent, α). QDI provides analogous tissue contrast to Diffusional Kurtosis Imaging (DKI) by calculation of normalised entropy of the parameterised diffusion signal decay curve, Hn, but does so without the limitations of a maximum b-value. We show that QDI generates images with superior tissue contrast to conventional diffusion imaging within clinically acceptable acquisition times of between 84 and 228 s. We show that QDI provides clinically meaningful images in cerebral small vessel disease and brain tumour case studies. Our initial findings suggest that QDI may be added to routine conventional dMRI acquisitions allowing simple application in clinical trials and translation to the clinical arena