Achieving best value in private finance initiative project procurement

The wherewithal of achieving best value in private finance initiative (PFI) projects and the associated problems therein are documented. In the UK, PFI has offered a solution to the problem of securing necessary investment at a time of severe public expenditure restraint. In PFI schemes, the public sector clients must secure value for money, while the private sector service providers must genuinely assume responsibility for project risks. A broad‐based investigation into PFI risk management informs the discussion in this paper. It is based on 68 interviews with PFI participants and a case study of eight PFI projects. The research participants comprised of contractors, financial institutions, public sector clients, consultants and facilities management organizations. The qualitative software Atlas.ti was used to analyse the textual data generated. The analysis showed that the achievement of best value requirements through PFI should hinge on: detailed risk analysis and appropriate risk allocation, drive for faster project completion, curtailment in project cost escalation, encouragement of innovation in project development, and maintenance cost being adequately accounted for. Factors that continue to challenge the achievement of best value are: high cost of the PFI procurement process, lengthy and complex negotiations, difficulty in specifying the quality of service, pricing of facility management services, potential conflicts of interests among those involved in the procurement, and the public sector clients' inability to manage consultants.     

Performance of BICM-OFDM systems in UWB interference

In this paper, we develop an analytical framework for performance analysis of generic bit-interleaved coded modulation orthogonal frequency-division multiplexing (BICMOFDM) systems impaired by ultra-wideband (UWB) interference. For practical relevance we consider multi-band OFDM (MB-OFDM), direct-sequence UWB (DS-UWB), and impulseradio UWB (IR-UWB) interference formats following recent IEEE/ECMA standards or standard proposals. Besides the exact analysis we calculate the bit error rate (BER) for the case when the UWB interference is modeled as additional Gaussian noise. Our results show that in general the BER of the BICM-OFDM system strongly depends on the UWB format and the OFDM sub-carrier spacing. While the Gaussian approximation is very accurate for DS-UWB, it may severely overor underestimate the true BER for MB-OFDM and IR-UWB interference. Our analysis is applicable to e.g. IEEE 802.11 wireless local area networks (WLANs), IEEE 802.16 wireless access systems (WiMAX), and 4th generation mobile communication systems. Furthermore, since the ECMA MB-OFDM standard is also based on the BICM-OFDM concept, our analysis can also be used to evaluate the impact of other UWB signals on ECMA MB-OFDM UWB systems.     

Microvia filling by copper electroplating using diazine black as a leveler

An organic additive, Diazine Black (DB), was employed as a leveler for microvia filling using copper electroplating. DB is a derivative of Janus Green B (JGB), which is a common leveler used for copper fill of submicron or micron circuit metallization in electronic products. This study determined the optimal DB concentration for achieving the best filling performance. The electrochemical behavior of DB and its interaction with other additives, such as a suppressor and an accelerator were characterized using galvanostatic measurements. These electrochemical analyses helped explaining the filling mechanism of the plating formula containing the DB. Various surface morphologies and the crystalline orientation of the plated copper films caused by different DB concentrations were characterized by a scanning electron microscope (SEM) and X-ray diffraction (XRD), respectively. The corresponding chemical activity of the surface atoms of the plated copper films caused by different DB concentrations was characterized using a test of etching rate.     

可互操作的GIS研究

随着“计算机就是网络”的想望成为实现,人们希望独立于数据结构和语义等具体条件,跨平台地获取大量信息,GIS互操作是广大用户跨平台获取地理信息的有效途径,因而它成为目前GIS界的研究热点。按照侧重点的不同,将GIS互操作分为技术互操作,服务互操作和语义互操作三类,并分别说明三者的实现方法,关建技术,研究现状和不足之处,最后对GIS互操作的发展方向进行了展望。     

Gamma interferon production by cytotoxic T lymphocytes is required for resolution of Chlamydia trachomatis infection

In this study, we used mice in which the gene for gamma interferon (IFN-gamma) has been disrupted (IFN-gamma-/- mice) to study the role of this cytokine in the resolution of Chlamydia trachomatis infection. We show that IFN-gamma-/- mice are impaired in the ability to clear infection with C. trachomatis compared to IFN-gamma+/+ control mice. Activated CD8(+) cytotoxic T lymphocytes (CTL) secrete IFN-gamma in response to intracellular infection, and we have shown previously that a Chlamydia-specific CTL line can reduce C. trachomatis infection when adoptively transferred into infected mice. In the present study, we found that when these IFN-gamma+/+ CTL lines are transferred into Chlamydia-infected IFN-gamma-/- mice, the transferred CTL cannot overcome the immune defect seen in the IFN-gamma-/- mice. We also show that Chlamydia-specific CTL can be cultured from IFN-gamma-deficient mice infected with C. trachomatis; however, the adoptive transfer of IFN-gamma-/- CTL into infected IFN-gamma+/+ mice does not reduce the level of infection. These results suggest that IFN-gamma production by CTL is not sufficient to overcome the defect that IFN-gamma-/- mice have in the resolution of Chlamydia infection, yet IFN-gamma production by CTL is required for the protective effect seen upon adoptive transfer of CTL into IFN-gamma+/+ mice.     

Cultivating Social Resources on Social Network Sites: Facebook Relationship Maintenance Behaviors and Their Role in Social Capital Processes

This study explores the relationship between perceived bridging social capital and specific Facebook‐enabled communication behaviors using survey data from a sample of U.S. adults (N=614). We explore the role of a specific set of Facebook behaviors that support relationship maintenance and assess the extent to which demographic variables, time on site, total and “actual” Facebook Friends, and this new measure (Facebook Relationship Maintenance Behaviors) predict bridging social capital. Drawing upon scholarship on social capital and relationship maintenance, we discuss the role of social grooming and attention‐signaling activities in shaping perceived access to resources in one's network as measured by bridging social capital.     

Toward Predictive Multiscale Modeling of Vascular Tumor Growth

New directions in medical and biomedical sciences have gradually emerged over recent years that will change the way diseases are diagnosed and treated and are leading to the redirection of medicine toward patient-specific treatments. We refer to these new approaches for studying biomedical systems as predictive medicine, a new version of medical science that involves the use of advanced computer models of biomedical phenomena, high-performance computing, new experimental methods for model data calibration, modern imaging technologies, cutting-edge numerical algorithms for treating large stochastic systems, modern methods for model selection, calibration, validation, verification, and uncertainty quantification, and new approaches for drug design and delivery, all based on predictive models. The methodologies are designed to study events at multiple scales, from genetic data, to sub-cellular signaling mechanisms, to cell interactions, to tissue physics and chemistry, to organs in living human subjects. The present document surveys work on the development and implementation of predictive models of vascular tumor growth, covering aspects of what might be called modeling-and-experimentally based computational oncology. The work described is that of a multi-institutional team, centered at ICES with strong participation by members at M. D. Anderson Cancer Center and University of Texas at San Antonio. This exposition covers topics on signaling models, cell and cell-interaction models, tissue models based on multi-species mixture theories, models of angiogenesis, and beginning work of drug effects. A number of new parallel computer codes for implementing finite-element methods, multi-level Markov Chain Monte Carlo sampling methods, data classification methods, stochastic PDE solvers, statistical inverse algorithms for model calibration and validation, models of events at different spatial and temporal scales is presented. Importantly, new methods for model selection in the presence of uncertainties fundamental to predictive medical science, are described which are based on the notion of Bayesian model plausibilities. Also, as part of this general approach, new codes for determining the sensitivity of model outputs to variations in model parameters are described that provide a basis for assessing the importance of model parameters and controlling and reducing the number of relevant model parameters. Model specific data is to be accessible through careful and model-specific platforms in the Tumor Engineering Laboratory. We describe parallel computer platforms on which large-scale calculations are run as well as specific time-marching algorithms needed to treat stiff systems encountered in some phase-field mixture models. We also cover new non-invasive imaging and data classification methods that provide in vivo data for model validation. The study concludes with a brief discussion of future work and open challenges.     

气流床气化炉的CPFD数值模拟

利用CPFD(computational particle fluid dynamics)模拟方法对三维、全尺寸的气流床气化炉进行了模拟计算,建立起了适用于CPFD模拟方法的气化模拟模型。模拟结果与实验数据相一致,说明模型基本准确且CPFD模拟方法适用于气流床气化过程的模拟。借由CPFD模拟方法给出了颗粒相在气化炉中的具体反应历程及颗粒停留时间的概率分布;结果表明,在单喷嘴顶喷的气化炉中,同时存在颗粒相的轴向流动短路及返混,短路主要发生在炉中心区域;颗粒在炉中心区域反应剧烈而边壁区域反应则很缓慢,而且从气化炉流出的第一股短路颗粒主要由充分反应了的粉煤颗粒构成。     

The use of the analytical electron microscope EMMA-4 to study the solute distribution in thin foils: some applications to metals and minerals

Results are reported concerning the application of the analytical electron microscope EMMA-4 to the quantitative analysis of thin foils. A simple procedure by which the observed characteristic X-ray intensities from a thin foil sample can be converted into chemical weight fractions is described. This technique has been applied to study the partitioning of manganese between the carbide and ferrite phases during the isothermal decomposition of a eutectoid steel. The results show that it is possible to analyse the manganese content of the ferrite and carbide phases independently and the partitioning of manganese to the carbide phase has been followed as a function of time at the isothermal transformation temperature. The analysis of a calcium-rich pyroxene which contains calcium-poor precipitate lamellae is described. The results are consistent with the precipitation of a pigeonite, poor in calcium and rich in iron, from an augite host. The third example is the ‘in situ’ analysis of nitride precipitates in a stainless steel. The precipitates are known to contain either titanium or chromium, but it is impossible from morphological or diffraction evidence to differentiate between the two types of nitride. Combined electron microscopy and microprobe analysis is shown to be a rapid and positive means of identifying the precipitates.