75 research outputs found

    Modelling Long-Term Electricity Contracts at EEX

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    The main aim of this paper is to develop and calibrate an econometric model for modelling prices of long term electricity futures contracts. The calibration of our model is performed on data from EEX AG allowing us to capture the specific features of German electricity market. The data sample contains several structural breaks which have to be taken into account for modelling. We model the data with an ARIMAX model which reveals high correlation between the price of electricity futures contracts (namely Phelix Base Fututes with next year´s delivery) and prices of long-term futures contracts of fuels (namely coal, natural gas and crude oil). Besides this, also a share price index of representative electricity companies traded on Xetra, spread between 10Y and 1Y German bonds and exchange rate between EUR and USD appeared to have significant explanatory power over these futures contracts on EEX.electricity futures, EEX, ARIMAX, emission allowances

    Economic Sentiment Indicators in Germany and their Predictive Power for Stock Market

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    Institute of Economic StudiesInstitut ekonomických studiíFakulta sociálních vědFaculty of Social Science

    Analiza ryzyka dla obszaru spływu wód podziemnych do ujęcia Łazy Błędowskie GPW S.A. w Katowicach i jej ograniczenia

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    The paper presents the procedure of risk assessment for the catchment zone of the Łazy Błędowskie groundwater intake, performed in accordance with the Water Law Act. Identification and analysis of contamination sources resulting from the land use patterns, as well as water qualitative research and health risk assessment with a view to factors negatively affecting the water quality, were carried out based on the hydrogeological report and analyses. The limitation on risk assessment, constrained by specific local hydrogeological, hydrogeochemical and environmental conditions, was indicated, including the need to establish the sanitary protection zone for the 8bis well. The planned cessation of the activities of Zn-Pb ores mining in the Olkusz area and associated changes in hydrogeochemical and hydrodynamic conditions within the area of the Łazy Błędowskie groundwater intake were taken into account as well

    Selective targeting of activating and inhibitory Smads by distinct WWP2 ubiquitin ligase isoforms differentially modulates TGFβ signalling and EMT

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    Ubiquitin-dependent mechanisms have emerged as essential regulatory elements controlling cellular levels of Smads and TGFß-dependent biological outputs such as epithelial–mesenchymal transition (EMT). In this study, we identify a HECT E3 ubiquitin ligase known as WWP2 (Full-length WWP2-FL), together with two WWP2 isoforms (N-terminal, WWP2-N; C-terminal WWP2-C), as novel Smad-binding partners. We show that WWP2-FL interacts exclusively with Smad2, Smad3 and Smad7 in the TGFß pathway. Interestingly, the WWP2-N isoform interacts with Smad2 and Smad3, whereas WWP2-C interacts only with Smad7. In addition, WWP2-FL and WWP2-C have a preference for Smad7 based on protein turnover and ubiquitination studies. Unexpectedly, we also find that WWP2-N, which lacks the HECT ubiquitin ligase domain, can also interact with WWP2-FL in a TGFß-regulated manner and activate endogenous WWP2 ubiquitin ligase activity causing degradation of unstimulated Smad2 and Smad3. Consistent with our protein interaction data, overexpression and knockdown approaches reveal that WWP2 isoforms differentially modulate TGFß-dependent transcription and EMT. Finally, we show that selective disruption of WWP2 interactions with inhibitory Smad7 can stabilise Smad7 protein levels and prevent TGFß-induced EMT. Collectively, our data suggest that WWP2-N can stimulate WWP2-FL leading to increased activity against unstimulated Smad2 and Smad3, and that Smad7 is a preferred substrate for WWP2-FL and WWP2-C following prolonged TGFß stimulation. Significantly, this is the first report of an interdependent biological role for distinct HECT E3 ubiquitin ligase isoforms, and highlights an entirely novel regulatory paradigm that selectively limits the level of inhibitory and activating Smads

    How ubiquitination regulates the TGF-β signalling pathway: New insights and new players

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    Ubiquitination of protein species in regulating signal transduction pathways is universally accepted as of fundamental importance for normal development, and defects in this process have been implicated in the progression of many human diseases. One pathway that has received much attention in this context is transforming growth factor-beta (TGF-ß) signalling, particularly during the regulation of epithelial-mesenchymal transition (EMT) and tumour progression. While E3-ubiquitin ligases offer themselves as potential therapeutic targets, much remains to be unveiled regarding mechanisms that culminate in their regulation. With this in mind, the focus of this review highlights the regulation of the ubiquitination pathway and the significance of a recently described group of NEDD4 E3-ubiquitin ligase isoforms in the context of TGF-ß pathway regulation. Moreover, we now broaden these observations to incorporate a growing number of protein isoforms within the ubiquitin ligase superfamily as a whole, and discuss their relevance in defining a new ‘iso-ubiquitinome’

    Rapid induction of pluripotency genes after exposure of human somatic cells to mouse ES cell extracts

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    The expression of 4 pluripotency genes (Oct4, Sox2, c-Myc and Klf4) in mouse embryonic fibroblasts can reprogramme them to a pluripotent state. We have investigated the expression of these pluripotency genes when human somatic 293T cells are permeabilised and incubated in extracts of mouse embryonic stem (ES) cells. Expression of all 4 genes was induced over 1 - 8 hours. Gene expression was associated with loss of repressive histone H3 modifications and increased recruitment of RNA polymerase II at the promoters. Lamin A/C, which is typically found only in differentiated cells, was also removed from the nuclei. When 293T cells were returned to culture after exposure to ES cell extract, the expression of the pluripotency genes continued to rise over the following 48 hours of culture, suggesting that long-term reprogramming of gene expression had been induced. This provides a methodology for studying the de-differentiation of somatic cells that can potentially lead to an efficient way of reprogramming somatic cells to a pluripotent state without genetically altering them

    Human Endometrial Side Population Cells Exhibit Genotypic, Phenotypic and Functional Features of Somatic Stem Cells

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    During reproductive life, the human endometrium undergoes around 480 cycles of growth, breakdown and regeneration should pregnancy not be achieved. This outstanding regenerative capacity is the basis for women's cycling and its dysfunction may be involved in the etiology of pathological disorders. Therefore, the human endometrial tissue must rely on a remarkable endometrial somatic stem cells (SSC) population. Here we explore the hypothesis that human endometrial side population (SP) cells correspond to somatic stem cells. We isolated, identified and characterized the SP corresponding to the stromal and epithelial compartments using endometrial SP genes signature, immunophenotyping and characteristic telomerase pattern. We analyzed the clonogenic activity of SP cells under hypoxic conditions and the differentiation capacity in vitro to adipogenic and osteogenic lineages. Finally, we demonstrated the functional capability of endometrial SP to develop human endometrium after subcutaneous injection in NOD-SCID mice. Briefly, SP cells of human endometrium from epithelial and stromal compartments display genotypic, phenotypic and functional features of SSC
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