736 research outputs found

    Provision of renewable energy using green certificates: market power and price limits

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    We formulate an analytic equilibrium model for simultaneously functioning electricity market an a market for Green Certificates. The major focus of the paper is the effect of market power in a Green Certificate system. One of the main results is that the certificate system faced with market power basically may collapse into a system of feed in tariffs.

    Market Power in Interactive Environmental and Energy Markets: The case of Green Certificates

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    Markets for environmental externalities are typically closely related to the markets causing such externalities, whereupon strategic interactions may result. Along these lines, the market for Green Certificates is strongly interwoven in the electricity market as the producers of green electricity are also suppliers of Green Certificates. In this paper, we formulate an analytic equilibrium model for simultaneously functioning electricity and Green Certificates markets, and focus on the role of market power. We consider two versions of a Nash-Cournot game; a standard Nash-Cournot game where the players treat the market for Green Certificates and the electricity market as separate markets; and a Nash-Cournot game with endogenous treatment of the interaction between the electricity and Green Certificates markets with conjectured responses. One result is that a certificate system faced with market power may collapse into a system of per unit subsidies, as the producers involved start to game on the joint functioning of markets.renewable energy; electricity; Green Certificates; market power

    Provision of Renewable Energy using Green Certificates: Market Power and Price Limits

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    We formulate an analytic equilibrium model for simultaneously functioning electricity market and a market for Green Certificates. The major focus of the paper is the effect of market power in a Green Certificate system. One of the main results from the analysis is that the certificate system faced with market power basically may collapse into a system of per unit subsidies.Firm Behavior: Theory; Oligopoly and Other Forms of Market Imperfection; Externalities; Redistributive Effects; Environmental Taxes and Subsidies; Production; Pricing; and Market Structure; Size Distribution of Firms; Electric Utilities

    Integratation of Tradable Green Certificate Markets: What can be expected?

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    Recently, many countries have introduced systems of tradable green certificates (TGCs) in order to increase the proportion of their electricity supply obtained from renewable sources. The main objective of this paper is to investigate the analytics of a TGC system of the Nordic type when integrated within several countries and to determine what can be expected from the system when applied in a real world setting. Both an analytical and a partial equilibrium version of the model are applied. In particular, we ask whether it is possible to derive analytically clear cut results with respect to how the system affects generation of electricity from renewable resources, and from carbon emitting resources, in the same way as it is possible for other known policy instruments such as an emission permit system or a plain carbon emission tax. A key result is that TGCs may be an imprecise instrument for regulating the generation of green electricity and that the combination of TGCs with a system of tradable emission permits may yield outcomes contrary to the intended purpose.Renewable energy; electricity; green certificates; emissions trading

    Highly sensitive and label-free digital detection of whole cell E. coli with interferometric reflectance imaging

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    Bacterial infectious diseases are a major threat to human health. Timely and sensitive pathogenic bacteria detection is crucial in identifying the bacterial contaminations and preventing the spread of infectious diseases. Due to limitations of conventional bacteria detection techniques there have been concerted research efforts towards development of new biosensors. Biosensors offering label free, whole bacteria detection are highly desirable over those relying on label based or pathogenic molecular components detection. The major advantage is eliminating the additional time and cost required for labeling or extracting the desired bacterial components. Here, we demonstrate rapid, sensitive and label free E. coli detection utilizing interferometric reflectance imaging enhancement allowing for visualizing individual pathogens captured on the surface. Enabled by our ability to count individual bacteria on a large sensor surface, we demonstrate a limit of detection of 2.2 CFU/ml from a buffer solution with no sample preparation. To the best of our knowledge, this high level of sensitivity for whole E. coli detection is unprecedented in label free biosensing. The specificity of our biosensor is validated by comparing the response to target bacteria E. coli and non target bacteria S. aureus, K. pneumonia and P. aeruginosa. The biosensor performance in tap water also proves that its detection capability is unaffected by the sample complexity. Furthermore, our sensor platform provides high optical magnification imaging and thus validation of recorded detection events as the target bacteria based on morphological characterization. Therefore, our sensitive and label free detection method offers new perspectives for direct bacterial detection in real matrices and clinical samples.First author draf

    Identification by using MALDI-TOF mass spectrometry of lactic acid bacteria isolated from non-commercial yogurts in southern Anatolia, Turkey

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    Yogurt is a dairy product obtained by bacterial fermentation of milk. Commercial yogurts are produced using standard starters while, in the production of non-commercial yogurt, the microbiota is quite different since yogurts are used as starter for years. To determine the final characteristics of the fermented product it is necessary to know the biochemical properties of the starter cultures, such as acidity, aroma and flavor. This can only be achieved by identifying and characterizing the bacteria in starter cultures. In our study, 208 non-commercial yogurt samples were collected from 9 different locations in Anatolia, southern Turkey. Their pH and lactic acid bacteria profiles were analyzed. Isolated bacteria were identified by MALDI-TOF MS (matrix-assisted laser sesorption-ionization time-of-flight, mass spectrometry), which is a fast and reliable method for identification of bacterial isolates compared to classical laboratory methods. In this study, 41% of the isolates were identified by using this method, which is 99.9% and 34.0% confidence. The isolates contained two genera (Enterococcus and Lactobacillus) and four species. Afterwards, the four lactic acid bacteria were characterized physiologically and biochemically and we found that they differed from lactic acid bacteria used in commercial yogurt production. [Int Microbiol 20(1): 25-30 (2017)]Keywords: yogurt starters · lactic acid bacteria (LAB) · southern Anatolia (Turkey

    Recurrence Plot Based Measures of Complexity and its Application to Heart Rate Variability Data

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    The knowledge of transitions between regular, laminar or chaotic behavior is essential to understand the underlying mechanisms behind complex systems. While several linear approaches are often insufficient to describe such processes, there are several nonlinear methods which however require rather long time observations. To overcome these difficulties, we propose measures of complexity based on vertical structures in recurrence plots and apply them to the logistic map as well as to heart rate variability data. For the logistic map these measures enable us not only to detect transitions between chaotic and periodic states, but also to identify laminar states, i.e. chaos-chaos transitions. The traditional recurrence quantification analysis fails to detect the latter transitions. Applying our new measures to the heart rate variability data, we are able to detect and quantify the laminar phases before a life-threatening cardiac arrhythmia occurs thereby facilitating a prediction of such an event. Our findings could be of importance for the therapy of malignant cardiac arrhythmias

    The complete mitochondrial genome of the foodborne parasitic pathogen Cyclospora cayetanensis

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    Cyclospora cayetanensis is a human-specific coccidian parasite responsible for several food and water-related outbreaks around the world, including the most recent ones involving over 900 persons in 2013 and 2014 outbreaks in the USA. Multicopy organellar DNA such as mitochondrion genomes have been particularly informative for detection and genetic traceback analysis in other parasites. We sequenced the C. cayetanensis genomic DNA obtained from stool samples from patients infected with Cyclospora in Nepal using the Illumina MiSeq platform. By bioinformatically filtering out the metagenomic reads of non-coccidian origin sequences and concentrating the reads by targeted alignment, we were able to obtain contigs containing Eimeria-like mitochondrial, apicoplastic and some chromosomal genomic fragments. A mitochondrial genomic sequence was assembled and confirmed by cloning and sequencing targeted PCR products amplified from Cyclospora DNA using primers based on our draft assembly sequence. The results show that the C. cayetanensis mitochondrion genome is 6274 bp in length, with 33% GC content, and likely exists in concatemeric arrays as in Eimeria mitochondrial genomes. Phylogenetic analysis of the C. cayetanensis mitochondrial genome places this organism in a tight cluster with Eimeria species. The mitochondrial genome of C. cayetanensis contains three protein coding genes, cytochrome (cytb), cytochrome C oxidase subunit 1 (cox1), and cytochrome C oxidase subunit 3 (cox3), in addition to 14 large subunit (LSU) and nine small subunit (SSU) fragmented rRNA genes

    Linkage mapping of putative regulator genes of barley grain development characterized by expression profiling

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    <p>Abstract</p> <p>Background</p> <p>Barley (<it>Hordeum vulgare </it>L.) seed development is a highly regulated process with fine-tuned interaction of various tissues controlling distinct physiological events during prestorage, storage and dessication phase. As potential regulators involved within this process we studied 172 transcription factors and 204 kinases for their expression behaviour and anchored a subset of them to the barley linkage map to promote marker-assisted studies on barley grains.</p> <p>Results</p> <p>By a hierachical clustering of the expression profiles of 376 potential regulatory genes expressed in 37 different tissues, we found 50 regulators preferentially expressed in one of the three grain tissue fractions pericarp, endosperm and embryo during seed development. In addition, 27 regulators found to be expressed during both seed development and germination and 32 additional regulators are characteristically expressed in multiple tissues undergoing cell differentiation events during barley plant ontogeny. Another 96 regulators were, beside in the developing seed, ubiquitously expressed among all tissues of germinating seedlings as well as in reproductive tissues. SNP-marker development for those regulators resulted in anchoring 61 markers on the genetic linkage map of barley and the chromosomal assignment of another 12 loci by using wheat-barley addition lines. The SNP frequency ranged from 0.5 to 1.0 SNP/kb in the parents of the various mapping populations and was 2.3 SNP/kb over all eight lines tested. Exploration of macrosynteny to rice revealed that the chromosomal orders of the mapped putative regulatory factors were predominantly conserved during evolution.</p> <p>Conclusion</p> <p>We identified expression patterns of major transcription factors and signaling related genes expressed during barley ontogeny and further assigned possible functions based on likely orthologs functionally well characterized in model plant species. The combined linkage map and reference expression map of regulators defined in the present study offers the possibility of further directed research of the functional role of regulators during seed development in barley.</p
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