978 resultados para Reactive power capability


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A newly completed study commissioned by the Iowa Office of Energy Independence shows increased jobs, tax revenue and economic activity as a result of Iowa Power Fund projects. The analysis is divided into two parts. Part I assesses the specific impacts of projects that have been funded directly. Part II offers an analysis of the long term impacts when projects are successfully replicated.

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Radioactive soil-contamination mapping and risk assessment is a vital issue for decision makers. Traditional approaches for mapping the spatial concentration of radionuclides employ various regression-based models, which usually provide a single-value prediction realization accompanied (in some cases) by estimation error. Such approaches do not provide the capability for rigorous uncertainty quantification or probabilistic mapping. Machine learning is a recent and fast-developing approach based on learning patterns and information from data. Artificial neural networks for prediction mapping have been especially powerful in combination with spatial statistics. A data-driven approach provides the opportunity to integrate additional relevant information about spatial phenomena into a prediction model for more accurate spatial estimates and associated uncertainty. Machine-learning algorithms can also be used for a wider spectrum of problems than before: classification, probability density estimation, and so forth. Stochastic simulations are used to model spatial variability and uncertainty. Unlike regression models, they provide multiple realizations of a particular spatial pattern that allow uncertainty and risk quantification. This paper reviews the most recent methods of spatial data analysis, prediction, and risk mapping, based on machine learning and stochastic simulations in comparison with more traditional regression models. The radioactive fallout from the Chernobyl Nuclear Power Plant accident is used to illustrate the application of the models for prediction and classification problems. This fallout is a unique case study that provides the challenging task of analyzing huge amounts of data ('hard' direct measurements, as well as supplementary information and expert estimates) and solving particular decision-oriented problems.

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We consider the asymptotic behaviour of the realized power variation of processes of the form ¿t0usdBHs, where BH is a fractional Brownian motion with Hurst parameter H E(0,1), and u is a process with finite q-variation, q<1/(1¿H). We establish the stable convergence of the corresponding fluctuations. These results provide new statistical tools to study and detect the long-memory effect and the Hurst parameter.

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L'hyperhémie réactive, définie comme l'augmentation transitoire du flux sanguin après une courte période d'ischémie, pourrait être influencée par des vasoconstricteurs de la famille des prostanoïdes, telle que la thromboxane. Le terutroban (S18886) est un antagoniste spécifique des récepteurs à la thromboxane. L'étude présentée a cherché à déterminer l'effet du terutroban sur l'hyperhémie réactive dans la peau et le muscle squelettique de l'avant-bras de volontaires sains. Vingt volontaires sains ont été randomisés en aveugle pour recevoir oralement 30mg/j de terutroban ou un placebo pendant 5 jours puis réciproquement pendant une deuxième période de 5 jours, selon un schéma cross-over. L'ischémie transitoire a été provoquée par l'occlusion de l'artère brachiale par une manchette gonflée au dessus de la pression systolique. L'hyperhémie réactive était évaluée dans les tissus de l'avant- bras, en mesurant le flux sanguin, pour la peau par une méthode laser Doppler, et pour le muscle au moyen d'une pléthysmographie par jauge de contrainte durant une occlusion veineuse. Au premier et au dernier jour de chaque période de traitement, l'hyperhémie réactive était mesurée avant et 2 heures après l'ingestion du comprimé. Que ce soit dans la peau ou le muscle, le terutroban n'a pas montré d'effet sur le flux de pic post-occlusion ni sur la réponse globale d'hyperhémie, exprimée en aire sous la courbe. En conclusion, dans la peau et le muscle de sujets sains, l'hypérémie réactive n'est pas influencée par les récepteurs spécifiques à la thromboxane.

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We characterize the value function of maximizing the total discounted utility of dividend payments for a compound Poisson insurance risk model when strictly positive transaction costs are included, leading to an impulse control problem. We illustrate that well known simple strategies can be optimal in the case of exponential claim amounts. Finally we develop a numerical procedure to deal with general claim amount distributions.

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ABSTRACT : A firm's competitive advantage can arise from internal resources as well as from an interfirm network. -This dissertation investigates the competitive advantage of a firm involved in an innovation network by integrating strategic management theory and social network theory. It develops theory and provides empirical evidence that illustrates how a networked firm enables the network value and appropriates this value in an optimal way according to its strategic purpose. The four inter-related essays in this dissertation provide a framework that sheds light on the extraction of value from an innovation network by managing and designing the network in a proactive manner. The first essay reviews research in social network theory and knowledge transfer management, and identifies the crucial factors of innovation network configuration for a firm's learning performance or innovation output. The findings suggest that network structure, network relationship, and network position all impact on a firm's performance. Although the previous literature indicates that there are disagreements about the impact of dense or spare structure, as well as strong or weak ties, case evidence from Chinese software companies reveals that dense and strong connections with partners are positively associated with firms' performance. The second essay is a theoretical essay that illustrates the limitations of social network theory for explaining the source of network value and offers a new theoretical model that applies resource-based view to network environments. It suggests that network configurations, such as network structure, network relationship and network position, can be considered important network resources. In addition, this essay introduces the concept of network capability, and suggests that four types of network capabilities play an important role in unlocking the potential value of network resources and determining the distribution of network rents between partners. This essay also highlights the contingent effects of network capability on a firm's innovation output, and explains how the different impacts of network capability depend on a firm's strategic choices. This new theoretical model has been pre-tested with a case study of China software industry, which enhances the internal validity of this theory. The third essay addresses the questions of what impact network capability has on firm innovation performance and what are the antecedent factors of network capability. This essay employs a structural equation modelling methodology that uses a sample of 211 Chinese Hi-tech firms. It develops a measurement of network capability and reveals that networked firms deal with cooperation between, and coordination with partners on different levels according to their levels of network capability. The empirical results also suggests that IT maturity, the openness of culture, management system involved, and experience with network activities are antecedents of network capabilities. Furthermore, the two-group analysis of the role of international partner(s) shows that when there is a culture and norm gap between foreign partners, a firm must mobilize more resources and effort to improve its performance with respect to its innovation network. The fourth essay addresses the way in which network capabilities influence firm innovation performance. By using hierarchical multiple regression with data from Chinese Hi-tech firms, the findings suggest that there is a significant partial mediating effect of knowledge transfer on the relationships between network capabilities and innovation performance. The findings also reveal that the impacts of network capabilities divert with the environment and strategic decision the firm has made: exploration or exploitation. Network constructing capability provides a greater positive impact on and yields more contributions to innovation performance than does network operating capability in an exploration network. Network operating capability is more important than network constructing capability for innovative firms in an exploitation network. Therefore, these findings highlight that the firm can shape the innovation network proactively for better benefits, but when it does so, it should adjust its focus and change its efforts in accordance with its innovation purposes or strategic orientation.

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A newly completed study commissioned by the Iowa Office of Energy Independence shows increased jobs, tax revenue and economic activity as a result of Iowa Power Fund projects. The analysis is divided into two parts. Part I assesses the specific impacts of projects that have been funded directly. Part II offers an analysis of the long term impacts when projects are successfully replicated.

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ISU’s proposed research will (1) develop methods for designing clean and efficient burners for low‐Btu producer gas and medium‐Btu syngas, (2) develop catalysts and flow reactors to produce ethanol from medium‐Btu synthesis gas, and (3) upgrade the BECON gasifier system to enable medium‐Btu syngas production and greatly enhanced capabilities for detailed gas analysis needed by both (1) and (2). This project addresses core development needs to enable grain ethanol industry reduce its natural gas demand and ultimately transition to cellulosic ethanol production.

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Power Fund Awarded Projects from the Office of Energy Independence.

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Power Fund Awarded Projects from the Office of Energy Independence.

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Rapid production of IL-4 by Leishmania homolog of mammalian RACK1 (LACK)-reactive CD4(+) T cells expressing the V beta 4-V alpha 8 TCR chains has been shown to drive aberrant Th2 cell development and susceptibility to Leishmania major in BALB/c mice. In contrast, mice from resistant strains fail to express this early IL-4 response. However, administration of either anti-IL-12 or -IFN-gamma at the initiation of infection allows the expression of this early IL-4 response in resistant mice. In this work we show that Leishmania homolog of mammalian RACK1-reactive CD4(+) T cells also expressing the V beta 4-V alpha 8 TCR chains are the source of the early IL-4 response to L. major in resistant mice given anti-IL-12 or -IFN-gamma Abs only at the onset of infection. Strikingly, these cells were found to be required for the reversal of the natural resistance of C57BL/6 mice following a single administration of anti-IL-12 or -IFN-gamma Abs. Together these results suggest that a deficiency in mechanisms capable of down-regulating the early IL-4 response to L. major contributes to the exquisite susceptibility of BALB/c mice to L. major.

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Community-acquired pneumonia (CAP) is a major clinical problem in terms of morbidity, mortality, and use of hospital resources. It is well recognized that a delay in making the diagnosis and instituting appropriate antibiotic treatment is associated with an increased mortality. C-reactive protein may be helpful in the management of patients with CAP. CRP is widely used in the management of CAP, including diagnosis, prognosis and follow-up. But its usefulness is not known. The aim of this systematic review was to evaluate the usefulness of CRP in the diagnosis, prognosis and follow-up of CAP.

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BACKGROUND: High-sensitivity C-reactive protein (hs-CRP) is associated with several cardiovascular risk factors (CVRF) and with renal function markers. However, these associations have not been examined in populations in the African region. We analyzed the distribution of hs-CRP and the relationship with a broad set of CVRF, renal markers and carotid intima-media thickness (IMT), in the Seychelles (African region). METHODS: We conducted a survey in the population aged 25-64years (n=1255, participation rate: 80.2%). Analyses were restricted to persons of predominantly African descent (n=1011). RESULTS: Mean and median hs-CRP serum concentrations (mg/l) were 3.1 (SD 7.6) and 1.4 (IQR 0.7-2.9) in men and 4.5 (SD 6.7) and 2.2 (IQR 1.0-5.4) in women (p<0.001 for difference between men and women). hs-CRP was significantly associated with several conventional CVRF, and particularly strongly with markers of adiposity. With regards to renal markers, hs-CRP was strongly associated with cystatin C and with microalbuminuria but not with creatinine. hs-CRP was not associated with IMT. CONCLUSIONS: Serum concentration of hs-CRP was significantly associated with sex, several CVRF and selected renal function markers, which extends similar findings in Europe and in North America to a population in the African region. These findings can contribute to guide recommendations for the use of hs-CRP in clinical practice in the region.