Computing Cournot-Nash equilibria / 1441

Includes bibliographical references (p. 22-23)

Electricity production in a hydro system with a reservoir constraint

The purpose of this article is to analyze how market power may affect the allocation of production between seasons (summer and winter) in a hydro power system with reservoir constraints and inflow uncertainty. We find that even without market power the price in the summer season may be lower than the expected price in the winter season. Market power may in some situations lead to higher sales and lower price in summer than the competitive outcome and in other situations to the opposite result. Furthermore, market power may lead to a smaller price difference between summer and winter than in a competitive marke

Climate policy and the steel industry : achieving global emission reductions by an incomplete climate agreement

The steel industry is one of the largest sources of global CO2 emissions and hence a candidate for climate policies. A carbon tax on emissions in industrialized countries, however, will cause relocation of steel production to non-industrialized countries, and because of their relatively high emission intensities the effect on total emissions is ambiguous. Using a partial equilibrium model of the steel industry, this paper finds that global emissions from this industry are likely to decline substantially. This is primarily due to factor substitution within the integrated steel mills in the industrialized countries. Such effects are not well accounted for in economy wide models, which typically lump individual industries into aggregates. Furthermore, it is shown that border taxes on steel products are potentially useful instruments for achieving a given reduction in global emissions with less restructuring of domestic steel industry in the industrialized countries

Geothermal energy in Denmark

The Geological Survey of Denmark and Greenland (GEUS) has for many years been involved with research, advisory and consultancy services concerning the assessment of the geothermal energy potential in Denmark, in close cooperation with private and public partners. The Survey’s particular responsibility has been the development of geological models to describe and predict the distribution of sandstone reservoirs suitable for geothermal exploitation. Danish geothermal resources in known sandstone aquifers are estimated to be sufficient to cover household heating requirements in Denmark for more than a century (Sørensen et al. 1998)

Identifying potential geothermal reservoirs in Denmark

Concerns about climate change have led to increased interest in geothermal energy as one way of reducing the consumption of fossil fuels and thus limit CO2 emissions. Use of geothermal energy is based on well-established technologies, a high degree of security of supply, and little visual or noise inconvenience. More than one hundred plants have been established in Europe. There is a large potential for using geothermal energy from the Danish subsurface, as first pointed out by Balling (1976). Geothermal energy is highly suitable for district heating systems and is expected to cover a large part of the demand for district heating in the future. Two Danish geothermal plants, the Thisted plant in northern Jylland and the Margretheholm demonstration plant near Copenhagen (Fig. 1), have shown that it is possible to produce large amounts of warm water for district heating. Only 5–10% of the total energy output from the plant is used to extract the heat from the subsurface by pumping warm formation water to the surface and returning it to the subsurface in a closed system. The plants use absorption warmth pumps, which need steam and hence give rise to consumption of (fossil) fuel. Both Danish plants have two wells, a production well and an injection well in which the cooled formation water is returned to the geological reservoir at about 1 km away from the production point, in order to avoid mixing of warm and cold water (Fig. 2). Geothermal energy can also be used for electricity production, but Danish subsurface tem-peratures are currently not believed to be sufficiently high to produce electricity directly

In-situ X-ray Video Microscopy Studies of Al-Si Eutectic Solidification

In-situ studies of Al-Si eutectic growth has been carried out for the first time by X-ray video microscopy during directional solidification of Al-Si-Cu alloys with and without Sr-addtions. The unmodified eutectics showed distinctive non-isothermal growth dynamics, where Si-crystals attained needle-like tip morphologies and progressed under significantly higher undercooling than Al, leading to formation of an irregular eutectic with Si as the leading phase and subsequent nucleation of Al on the Si-surfaces. In the Sr-modified alloys, the eutectic reaction was found to be strongly suppressed, occurring with low nucleation frequencies at undercoolings in the range 10-18 K. In the Cu-enriched melt, the eutectic front was found to attain meso-scale interface perturbations evolving into equiaxed cellular rosettes in order to accommodate to the long-range redistribution of Cu from the composite eutectic interface. The eutectic front also attained short-range microscale interface perturbations consistent with characteristics of a fibrous Si growth, however further improvements in spatial resolution is required in order to study microscale structure formation in greater detail. Evidence was found in support of Si-nucleation occurring on potent particles suspended in the melt. Yet, both with Sr- modified and unmodified alloys, Si precipitation alone was not sufficient to facilitate the eutectic reaction, which apparently required additional undercooling for Al to form on the Si-particles. To what extent nucleation mechanisms in the Cu-enriched systems are transferable to binary or commercial Al-Si alloys remains uncertain

Decompressive hemicraniectomy for space-occupying brain infarction: Nationwide population-based registry study

Objective: We analyzed data from the Norwegian Stroke Registry (NSR) to study access to and outcomes of decompressive hemicraniectomy for brain infarction in a nationwide routine clinical setting. We also discretionary assessed whether the outcomes were comparable with those achieved in randomized controlled trials (RCTs), and whether the use was in accordance with guidelines. Methods: The NSR is a nationwide (population 5.3 million) clinical quality registry. We included all stroke-cases operated in 2017 through 2019, and retrieved data on baseline characteristics, treatment and functional outcome after three months (dichotomized modified Rankin Scale score; favorable (0-3) or unfavorable (4-6)). Crude treatment rates and the expected proportion of patients transferred from a local hospital to a stroke-center for the operation were estimated, based on the total population’s distribution of residency. Results: The 68 cases were 17 (25%) women and 51 (75%) men with a median National Institute of Health Stroke Scale (NIHSS) score on admission of 14.0 (inter-quartile range (IQR) 11.0) and a median time from onset to hemicraniectomy of 34.3 (IQR 40.9) hours. The crude treatment rate varied between regions from 0.29 to 1.40 operations per 100,000 population per year, and the proportion transferred from a local hospital (50%) was lower than expected (68%). A favorable outcome was achieved in 20/52 (38.5%) cases. Conclusions: The findings indicate gender- and geographic-inequalities in access. Among operated cases, outcomes were comparable with those reported from RCTs, and the use in accordance with recommendations in the current guidelines from the American Stroke Association

Genome-wide analysis of signal peptide functionality in Lactobacillus plantarum WCFS1

<p>Abstract</p> <p>Background</p> <p><it>Lactobacillus plantarum </it>is a normal, potentially probiotic, inhabitant of the human gastrointestinal (GI) tract. The bacterium has great potential as food-grade cell factory and for <it>in situ </it>delivery of biomolecules. Since protein secretion is important both for probiotic activity and in biotechnological applications, we have carried out a genome-wide experimental study of signal peptide (SP) functionality.</p> <p>Results</p> <p>We have constructed a library of 76 Sec-type signal peptides from <it>L. plantarum </it>WCFS1 that were predicted to be cleaved by signal peptidase I. SP functionality was studied using staphylococcal nuclease (NucA) as a reporter protein. 82% of the SPs gave significant extracellular NucA activity. Levels of secreted NucA varied by a dramatic 1800-fold and this variation was shown not to be the result of different mRNA levels. For the best-performing SPs all produced NucA was detected in the culture supernatant, but the secretion efficiency decreased for the less well performing SPs. Sequence analyses of the SPs and their cognate proteins revealed four properties that correlated positively with SP performance for NucA: high hydrophobicity, the presence of a transmembrane helix predicted by TMHMM, the absence of an anchoring motif in the cognate protein, and the length of the H+C domain. Analysis of a subset of SPs with a lactobacillal amylase (AmyA) showed large variation in production levels and secretion efficiencies. Importantly, there was no correlation between SP performance with NucA and the performance with AmyA.</p> <p>Conclusion</p> <p>This is the first comprehensive experimental study showing that predicted SPs in the <it>L. plantarum </it>genome actually are capable of driving protein secretion. The results reveal considerable variation between the SPs that is at least in part dependent on the protein that is secreted. Several SPs stand out as promising candidates for efficient secretion of heterologous proteins in <it>L. plantarum</it>. The results for NucA provide some hints as to the sequence-based prediction of SP functionality, but the general conclusion is that such prediction is difficult. The vector library generated in this study is based on exchangeable cassettes and provides a powerful tool for rapid experimental screening of SPs.</p