Patterns of international bond issuances : an empirical study of Norwegian firms

This thesis documents and analyses patterns associated with international bonds issued by Norwegian firms and compares them with patterns of domestic bond issuances. The analysis is focused towards characteristics and features at firm level. The analysis is based on empirical data from the recent period of 1998 – 2008 in order to encourage and guide future research. Three particularly noticeable patterns have been found: (1) The firms which issue bonds internationally have very different characteristics compared to the firms issuing only domestically. Firms issuing internationally have a significantly larger amount of assets, higher profitability, higher level of investment and ability to service debt. (2) Despite the link between firms doing business abroad and issuing bonds abroad, the shipping and fishfarming industries appear to be more attracted to the prominent and renowned features of the Norwegian domestic market. (3) Only 3 of the 25 banks underwriting domestic issues are responsible for underwriting Norwegian bonds internationally. This indicates that the recognition of the underwriter is as important as the recognition of the firm. These findings are then discussed in the light of existing theoretical views

Response of Methanogens in Arctic Sediments to Temperature and Methanogenic Substrate Availability

Although cold environments are major contributors to global biogeochemical cycles, comparatively little is known about their microbial community function, structure, and limits of activity. In this study a microcosm based approach was used to investigate the effects of temperature, and methanogenic substrate amendment, (acetate, methanol and H2/CO2) on methanogen activity and methanogen community structure in high Arctic wetlands (Solvatnet and Stuphallet, Svalbard). Methane production was not detected in Stuphallet sediment microcosms (over a 150 day period) and occurred within Solvatnet sediments microcosms (within 24 hours) at temperatures from 5 to 40°C, the maximum temperature being at far higher than in situ maximum temperatures (which range from air temperatures of -1.4 to 14.1°C during summer months). Distinct responses were observed in the Solvatnet methanogen community under different short term incubation conditions. Specifically, different communities were selected at higher and lower temperatures. At lower temperatures (5°C) addition of exogenous substrates (acetate, methanol or H2/CO2) had no stimulatory effect on the rate of methanogenesis or on methanogen community structure. The community in these incubations was dominated by members of the Methanoregulaceae/WCHA2-08 family-level group, which were most similar to the psychrotolerant hydrogenotrophic methanogen Methanosphaerula palustris strain E1-9c. In contrast, at higher temperatures, substrate amendment enhanced methane production in H2/CO2 amended microcosms, and played a clear role in structuring methanogen communities. Specifically, at 30°C members of the Methanoregulaceae/WCHA2-08 predominated following incubation with H2/CO2, and Methanosarcinaceaeand Methanosaetaceae were enriched in response to acetate addition. These results may indicate that in transiently cold environments, methanogen communities can rapidly respond to moderate short term increases in temperature, but not necessarily to the seasonal release of previously frozen organic carbon from thawing permafrost soils. However, as temperatures increase such inputs of carbon will likely have a greater influence on methane production and methanogen community structure. Understanding the action and limitations of anaerobic microorganisms within cold environments may provide information which can be used in defining region-specific differences in the microbial processes; which ultimately control methane flux to the atmosphere

The influence of above-ground herbivory on the response of arctic soil methanotrophs to increasing ch4 concentrations and temperatures

Rising temperatures in the Arctic affect soil microorganisms, herbivores, and peatland vegetation, thus directly and indirectly influencing microbial CH4 production. It is not currently known how methanotrophs in Arctic peat respond to combined changes in temperature, CH4 concentration, and vegetation. We studied methanotroph responses to temperature and CH4 concentration in peat exposed to herbivory and protected by exclosures. The methanotroph activity was assessed by CH4 oxidation rate measurements using peat soil microcosms and a pure culture of Methylobacter tundripaludum SV96, qPCR, and sequencing of pmoA transcripts. Elevated CH4 concentrations led to higher CH4 oxidation rates both in grazed and exclosed peat soils, but the strongest response was observed in grazed peat soils. Furthermore, the relative transcriptional activities of different methanotroph community members were affected by the CH4 concentrations. While transcriptional responses to low CH4 concentrations were more prevalent in grazed peat soils, responses to high CH4 concentrations were more prevalent in exclosed peat soils. We observed no significant methanotroph responses to increasing temperatures. We conclude that methanotroph communities in these peat soils respond to changes in the CH4 concentration depending on their previous exposure to grazing. This “conditioning” influences which strains will thrive and, therefore, determines the function of the methanotroph community

Microbial responses to herbivory-induced vegetation changes in a high-Arctic peatland

Herbivory by barnacle geese (Branta leucopsis) alters the vegetation cover and reduces ecosystem productivity in high-Arctic peatlands, limiting the carbon sink strength of these ecosystems. Here we investigate how herbivory-induced vegetation changes affect the activities of peat soil microbiota using metagenomics, metatranscriptomics and targeted metabolomics in a comparison of fenced exclosures and nearby grazed sites. Our results show that a different vegetation with a high proportion of vascular plants developed due to reduced herbivory, resulting in a larger and more diverse input of polysaccharides to the soil at exclosed study sites. This coincided with higher sugar and amino acid concentrations in the soil at this site as well as the establishment of a more abundant and active microbiota, including saprotrophic fungi with broad substrate ranges, like Helotiales (Ascomycota) and Agaricales (Basidiomycota). A detailed description of fungal transcriptional profiles revealed higher gene expression for cellulose, hemicellulose, pectin, lignin and chitin degradation at herbivory-exclosed sites. Furthermore, we observed an increase in the number of genes and transcripts for predatory eukaryotes such as Entomobryomorpha (Arthropoda). We conclude that in the absence of herbivory, the development of a vascular vegetation alters the soil polysaccharide composition and supports larger and more active populations of fungi and predatory eukaryotes

Abrupt permafrost thaw triggers activity of copiotrophs and microbiome predators

Permafrost soils store a substantial part of the global soil carbon and nitrogen. However, global warming causes abrupt erosion and gradual thaw, which make these stocks vulnerable to microbial decomposition into greenhouse gases. Here, we investigated the microbial response to abrupt in situ permafrost thaw. We sequenced the total RNA of a 1 m deep soil core consisting of up to 26 500-year-old permafrost material from an active abrupt erosion site. We analysed the microbial community in the active layer soil, the recently thawed, and the intact permafrost, and found maximum RNA:DNA ratios in recently thawed permafrost indicating a high microbial activity. In thawed permafrost, potentially copiotrophic Burkholderiales and Sphingobacteriales, but also microbiome predators dominated the community. Overall, both thaw-dependent and long-term soil properties significantly correlated with changes in community composition, as did microbiome predator abundance. Bacterial predators were dominated in shallower depths by Myxococcota, while protozoa, especially Cercozoa and Ciliophora, almost tripled in relative abundance in thawed layers. Our findings highlight the ecological importance of a diverse interkingdom and active microbial community highly abundant in abruptly thawing permafrost, as well as predation as potential biological control mechanism

Thermal acclimation of methanotrophs from the genus Methylobacter

Methanotrophs oxidize most of the methane (CH4) produced in natural and anthropogenic ecosystems. Often living close to soil surfaces, these microorganisms must frequently adjust to temperature change. While many environmental studies have addressed temperature effects on CH4 oxidation and methanotrophic communities, there is little knowledge about the physiological adjustments that underlie these effects. We have studied thermal acclimation in Methylobacter, a widespread, abundant, and environmentally important methanotrophic genus. Comparisons of growth and CH4 oxidation kinetics at different temperatures in three members of the genus demonstrate that temperature has a strong influence on how much CH4 is consumed to support growth at different CH4 concentrations. However, the temperature effect varies considerably between species, suggesting that how a methanotrophic community is composed influences the temperature effect on CH4 uptake. To understand thermal acclimation mechanisms widely we carried out a transcriptomics experiment with Methylobacter tundripaludum SV96T . We observed, at different temperatures, how varying abundances of transcripts for glycogen and protein biosynthesis relate to cellular glycogen and ribosome concentrations. Our data also demonstrated transcriptional adjustment of CH4 oxidation, oxidative phosphorylation, membrane fatty acid saturation, cell wall composition, and exopolysaccharides between temperatures. In addition, we observed differences in M. tundripaludum SV96T cell sizes at different temperatures. We conclude that thermal acclimation in Methylobacter results from transcriptional adjustment of central metabolism, protein biosynthesis, cell walls and storage. Acclimation leads to large shifts in CH4 consumption and growth efficiency, but with major differences between species. Thus, our study demonstrates that physiological adjustments to temperature change can substantially influence environmental CH4 uptake rates and that consideration of methanotroph physiology might be vital for accurate predictions of warming effects on CH4 emissions

Anaerobic oxidation of methane and associated microbiome in anoxic water of Northwestern Siberian lakes

Arctic lakes emit methane (CH4) to the atmosphere. The magnitude of this flux could increase with permafrost thaw but might also be mitigated by microbial CH4 oxidation. Methane oxidation in oxic water has been extensively studied, while the contribution of anaerobic oxidation of methane (AOM) to CH4 mitigation is not fully understood. We have investigated four Northern Siberian stratified lakes in an area of discontinuous permafrost nearby Igarka, Russia. Analyses of CH4 concentrations in the water column demonstrated that 60 to 100% of upward diffusing CH4 was oxidized in the anoxic layers of the four lakes. A combination of pmoA and mcrA gene qPCR and 16S rRNA gene metabarcoding showed that the same taxa, all within Methylomonadaceae and including the predominant genus Methylobacter as well as Crenothrix, could be the major methane-oxidizing bacteria (MOB) in the anoxic water of the four lakes. Correlation between Methylomonadaceae and OTUs within Methylotenera, Geothrix and Geobacter genera indicated that AOM might occur in an interaction between MOB, denitrifiers and iron-cycling partners. We conclude that MOB within Methylomonadaceae could have a crucial impact on CH4 cycling in these Siberian Arctic lakes by mitigating the majority of produced CH4 before it leaves the anoxic zone. This finding emphasizes the importance of AOM by Methylomonadaceae and extends our knowledge about CH4 cycle in lakes, a crucial component of the global CH4 cycle

Predictors of Poor Perinatal Outcome following Maternal Perception of Reduced Fetal Movements: A Prospective Cohort Study

Background Maternal perception of reduced fetal movement (RFM) is associated with increased risk of stillbirth and fetal growth restriction (FGR). RFM is thought to represent fetal compensation to conserve energy due to insufficient oxygen and nutrient transfer resulting from placental insufficiency. Objective To identify predictors of poor perinatal outcome after maternal perception of reduced fetal movements (RFM). Design Prospective cohort study. Methods 305 women presenting with RFM after 28 weeks of gestation were recruited. Demographic factors and clinical history were recorded and ultrasound performed to assess fetal biometry, liquor volume and umbilical artery Doppler. A maternal serum sample was obtained for measurement of placentally-derived or modified proteins including: alpha fetoprotein (AFP), human chorionic gonadotrophin (hCG), human placental lactogen (hPL), ischaemia-modified albumin (IMA), pregnancy associated plasma protein A (PAPP-A) and progesterone. Factors related to poor perinatal outcome were determined by logistic regression. Results 22.1% of pregnancies ended in a poor perinatal outcome after RFM. The most common complication was small-for-gestational age infants. Pregnancy outcome after maternal perception of RFM was related to amount of fetal activity while being monitored, abnormal fetal heart rate trace, diastolic blood pressure, estimated fetal weight, liquor volume, serum hCG and hPL. Following multiple logistic regression abnormal fetal heart rate trace (Odds ratio 7.08, 95% Confidence Interval 1.31–38.18), (OR) diastolic blood pressure (OR 1.04 (95% CI 1.01–1.09), estimated fetal weight centile (OR 0.95, 95% CI 0.94–0.97) and log maternal serum hPL (OR 0.13, 95% CI 0.02–0.99) were independently related to pregnancy outcome. hPL was related to placental mass. Conclusion Poor perinatal outcome after maternal perception of RFM is closely related to factors which are connected to placental dysfunction. Novel tests of placental function and associated fetal response may provide improved means to detect fetuses at greatest risk of poor perinatal outcome after RFM

A combined microbial and biogeochemical dataset from high-latitude ecosystems with respect to methane cycle.

High latitudes are experiencing intense ecosystem changes with climate warming. The underlying methane (CH4) cycling dynamics remain unresolved, despite its crucial climatic feedback. Atmospheric CH4 emissions are heterogeneous, resulting from local geochemical drivers, global climatic factors, and microbial production/consumption balance. Holistic studies are mandatory to capture CH4 cycling complexity. Here, we report a large set of integrated microbial and biogeochemical data from 387 samples, using a concerted sampling strategy and experimental protocols. The study followed international standards to ensure inter-comparisons of data amongst three high-latitude regions: Alaska, Siberia, and Patagonia. The dataset encompasses diferent representative environmental features (e.g. lake, wetland, tundra, forest soil) of these high-latitude sites and their respective heterogeneity (e.g. characteristic microtopographic patterns). The data included physicochemical parameters, greenhouse gas concentrations and emissions, organic matter characterization, trace elements and nutrients, isotopes, microbial quantifcation and composition. This dataset addresses the need for a robust physicochemical framework to conduct and contextualize future research on the interactions between climate change, biogeochemical cycles and microbial communities at highlatitudes

Inter-laboratory testing of the effect of DNA blocking reagent G2 on DNA extraction from low-biomass clay samples

Here we show that a commercial blocking reagent (G2) based on modifed eukaryotic DNA signifcantly improved DNA extraction efciency. We subjected G2 to an inter-laboratory testing, where DNA was extracted from the same clay subsoil using the same batch of kits. The inter-laboratory extraction campaign revealed large variation among the participating laboratories, but the reagent increased the number of PCR-amplifed16S rRNA genes recovered from biomass naturally present in the soils by one log unit. An extensive sequencing approach demonstrated that the blocking reagent was free of contaminating DNA, and may therefore also be used in metagenomics studies that require direct sequencing