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An assay was developed for the specific detection of Salmonella enterica serotype Enteritidis, using a novel application of the polymerase chain reaction (PCR). This PCR assay is based on the mismatch amplification mutation assay, an allele-specific reaction, and can discriminate Enteritidis from all other salmonella. PCR primers were selected to amplify a 351-base pair (bp) DNA fragment from the salmonella plasmid virulence A (spv A) gene of Enteritidis. A single base difference at position 272 is present between the nucleotide sequence of the spvA gene of Enteritidis and other salmonellae. The downstream PCR primer, that encompasses position 272 of the Enteritidis spvA gene, was designed to contain a single base mismatch at the penultimate position, resulting in a 1-base mismatch with Enteritidis and a 2-base mismatch with other salmonellae that harbour the virulence plasmid. The upstream primer was completely homologous with the region immediately 5' to the spvA gene. When these primers were used and the annealing and extension reactions were performed at the same temperature, the PCR assay was specific for Enteritidis; no PCR product was detected for 40 other serotypes and 28 different genera examined. In pure culture, 120 colony forming units (c.f.u.) could be detected; a PCR product was observed from template derived from a 5 h enrichment broth culture of chicken seeded with 1 c.f.u. per gram of Enteritidis. This PCR assay is specific, reproducible, and less time consuming than the standard bacteriological methods used to detect Enteritidis.  相似文献   
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In transitioning to a renewable material-based bio economy, growing public and industry interest is apparent for using wooden multistory construction (WMC) as a sustainable urban housing solution in Europe, but its business implications are not well understood. In our study, we evaluate, which internal and external factors of competitiveness are shaping the future of WMC, especially in the context of Finland and Sweden. Based on a multi-level perspective of socio-technical transitions, we conducted a three-stage dissensus-based Delphi study. The identified internal and external factors affecting the future competitiveness of the WMC business emphasize the importance of skilled architects and builders and the role of standardized building systems. Based on our results, the key aspects influencing the future competitiveness of WMC in the region are related to the development of technical infrastructure and project-based business networks, while additional changes in regulatory framework are perceived as less important. We conclude that towards 2030, the strong cognitive rules founded in the concrete-based building culture in these countries is likely to inhibit the dynamics of the socio-technical regime level. A change is also needed in the WMC business culture towards more open cross-sectoral collaboration and new business networks between different-sized players.  相似文献   
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Urgent protective measures for the possibly affected population in the pre-release and release phase of a nuclear accident are decided upon and implemented by civil protection authorities on regional and local level. The responsible officers of these authorities are experienced in emergency response, but not in radiological questions. Their radiological advisors, on the other hand, mostly coming from surveillance agencies, often lack knowledge about conditions framing practical response measures. Moreover, although the scientific basis of protective measures is unquestionable, implementation policies are widely different in different countries and render co-ordination of response in border areas difficult. Finally, decreasing availability of funds sharpens the already existing problems due to diminishing interest of young scientists in radiation protection. Measures to improve upon the situation and prerequisite conditions will be discussed.  相似文献   
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Accurate measurement of the perceived quality of audio–visual services at the end-user is becoming a crucial issue in digital applications due to the growing demand for compression and transmission of audio–visual services over communication networks. Content providers strive to offer the best quality of experience for customers linked to their different quality of service (QoS) solutions. Therefore, developing accurate, perceptual-based quality metrics is a key requirement in multimedia services. In this paper, we survey state-of-the-art signal-driven perceptual audio and video quality assessment methods independently, and investigate relevant issues in developing joint audio–visual quality metrics. Experiments with respect to subjective quality results have been conducted for analyzing and comparing the performance of the quality metrics. We consider emerging trends in audio–visual quality assessment, and propose feasible solutions for future work in perceptual-based audio–visual quality metrics.  相似文献   
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The fabrication and characterisation of low-loss InGaAsP/InP optical submicron waveguides made with ICP etching is reported. Their width ranges from 0.2 to 2 /spl mu/m. For the 0.5 /spl mu/m width, the propagation losses at /spl lambda/=1.55 /spl mu/m as low as 4.2 dB/mm have been measured.  相似文献   
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Foam is a frequently used compressible fluid in drilling applications. Cuttings transport with foam has been a focus of interest for years. Few studies have been conducted on vertical well configuration and successfully applied. However, less is known about the performance of foam in highly inclined and horizontal wells. In this study, a layered model is developed for describing cuttings transport in horizontal wells. Due to the presence of a cuttings bed, generalized rheological model parameters for foam are modified analytically as a function of fluid properties and complex conduit geometry. Using these parameters, friction between the fluid and the wellbore, between the layers and slip between the cuttings and the fluid are determined. Model performance is examined using experimental data established at The University of Tulsa's low pressure-ambient temperature flow loop. Results showed that, developed model can predict developed cuttings bed thickness and pressure loss in the wellbore with an error of less than 20%. It has been observed that very high foam flow velocities are required in order to prevent a thick bed development in the wellbore. Also, low-viscosity fluids show better performance on preventing bed development inside the wellbore than high-viscosity fluids at the same flow rates.  相似文献   
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Einflußvon Stahl- und Schlackenzusammensetzung im System Calciumfluorid-Kalk-Tonerde-Kieselsäure[-Eisen(II)-oxid] [CaF2–CaO–Al2O3–SiO2(–FeO)] auf die Sauerstoffgehalte in elektro-schlacke-umgeschmolzenen Stählen. Aussagen über die Entmischungstendenz des Eisen(II)-oxids in calciumfluoridhaltigen Schlacken unter den Bedingungen des Elektro-Schlacke-Umschmelzverfahrens. Folgerungen über die geschwindigkeitsbestimmenden Reaktionsteilschritte bei der Sauerstoffaufnahme durch Stahl und Schlacke während des Umschmelzens.  相似文献   
10.
3D video is composed out of two or more, temporally synchronized, 2D video streams acquired at different camera poses and accompanied by geometrical information. In a mixed resolution 3D video stream, a subset of views is coded at reduced resolution. It has been shown in the literature that subjective quality of mixed resolution 3D video is close to that of full resolution 3D video. In order to improve the coding gain in mixed resolution coding scenario we present a new depth encoding method called view upsampling optimization. A novel depth distortion metric based on the performance of the depth-based super resolution is also presented. Finally, to improve the quality of the decoded video an improved depth-based super resolution method that uses view synthesis quality mapping is used for upsampling of low resolution views. The simulations, performed with the recently standardized MVC+D encoder, show that the proposed solution combined with the state of the art view synthesis distortion outperforms the anchor MVC+D coding scheme by 14.5 % of dBR on average for the total coded bitrate and by 17 % of dBR on average for the synthesized views.  相似文献   
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