Life cycle cost considerations in project appraisals of collision-free roads

In the last decade, many single carriageway roads in Sweden have been converted to collision-free roads as a cost-effective alternative to conventional motorways. Investigations have concluded that the road type has been successful in reducing the number of fatal accidents, despite increased operation and maintenance costs. In recent years, the focus has shifted to converting narrower roads which are anticipated to further increase operation and maintenance cost but also complicate traffic management during road works. There are concerns that when life cycle cost is considered in the investment assessment the socioeconomic profitability could be reduced. This article examines this issue by first assessing changes in costs for operation and maintenance using a life cycle cost analysis approach applied on a case study. The results from the analysis were thereafter integrated into a cost–benefit analysis to assess changes in costs in relation to benefits in improved traffic safety and travel time. The analysis indicated profitability even with substantial increase in operation, maintenance and road user work zone costs. Results are discussed from project implementation and road management perspectives.     

Project managers and career models: An exploratory comparative study

Prior research has paid little attention to the careers and career models of project managers. This is troublesome for at least two reasons. First, project managers are becoming an increasingly important category of managers and today they constitute a major part of many organizations' leadership capability. Second, traditional literature on careers generally does not address project-based careers as a specific case in point, although this kind of career is unique in the sense that it is based on temporary assignments and lack of formal positions. The research presented in this paper identifies and explains patterns of similarities and differences among applied career models in ten large, mature project-intensive firms in Sweden. The paper identifies a number of factors that seem to be critical for the design of career models for project managers, including the number of levels, the complexity of assignments, and the degree of formal requirements. The paper also outlines two archetypes of career models applied by the firms under study: the competence strategy model and the talent management model.     

Business models in project business

Recent management and business research has demonstrated the importance of business models for value creation and company performance. So far, extant research on business models has not investigated the particular requirements, characteristics and combinations of business models in project business. This paper seeks to fill this void. The paper reports on findings from an exploratory multiple case study comprising six project-based firms operating in such industries as shipbuilding, telecom, and power systems. 19 business models were identified and compared through a framework utilizing elements of business models. The identified business models are further grouped into three categories based on the organizational entity. The paper points out the diversity of business models in project business and their inclination to span organizational levels. The results demonstrate the importance of addressing the combination of business models across organizational boundaries.     

Influence of Obstacles on the Development of Gravity Current Prior to Backdraft

The phenomenon of backdraft is closely linked to the formation of a flammable region due to the mixing process between the unburned gases accumulated in the compartment and the fresh air entering the compartment through a recently created opening. The flow of incoming fresh air is called the gravity current. Gravity current prior to backdraft has already been studied, Fleischmann (1993, Backdraft phenomena, NIST-GCR-94-646. University of California, Berkeley) and Fleischmann (1999, Numerical and experimental gravity currents related to backdrafts, Fire Safety Journal); Weng et al. (2002, Exp Fluids 33:398–404), but all simulations and experiments found in the current literature are systematically based on a perfectly regular volume, usually parallelipedic in shape, without any piece of furniture or equipment in the compartment. Yet, various obstacles are normally found in real compartments and the question is whether they affect the gravity current velocity and the level of mixing between fresh and vitiated gases. In the work reported here, gravity current prior to backdraft in compartment with obstacles is investigated by means of three-dimensional CFD numerical simulations. These simulations use as a reference case the backdraft experiment test carried out by Gojkovic (2000, Initial Backdraft. Department of Fire Safety Engineering, Lunds Tekniska Högskola Universitet, Report 3121). The Froude number, the transit time and the ignition time are obtained from the computations and compared to the tests in order to validate the model.     

A duplex real-time PCR assay for the quantitative detection of Naegleria fowleri in water samples

A fast and accurate duplex real-time PCR (qPCR) was developed to detect and quantify the human pathogenic amoeba Naegleria fowleri in water samples. In this study, primers and probe based on the Mp2Cl5 gene were designed to amplify and quantify N. fowleri DNA in a single duplex reaction. The qPCR detection limit (DL) corresponds to the minimum DNA quantity showing significant fluorescence with at least 90% of the positive controls in a duplex reaction. Using fluorescent Taqman technology the qPCR was found to be 100% specific for N. fowleri with a DL of 3 N. fowleri cell equivalents and a PCR efficiency of 99%. The quantification limit (QL) was 16 N. fowleri cell equivalents (corresponded with 320 N. fowleri cell equivalents l(-1) water sample) in a duplex qPCR reaction and corresponds to the lowest DNA quantity amplifiable with a coefficient of variation less than 25%. To detect inhibition an exogenous internal positive control (IPC) was included in each PCR reaction preventing false negative results. Comparison of qPCR and most probable number (MPN) culture results confirms that the developed qPCR is well suited for rapid and quantitative detection of this human pathogen in real water samples. Nevertheless 'low contamination levels' of water samples (<200 N. fowleri cells l(-1)) still require culture method analyses. When other thermophilic Naegleria are very dominant, the MPN culture method could result in an underestimation in the real number of N. fowleri and some caution is necessary to interpret the data. The N. fowleri qPCR could be a useful tool to study further competitive phenomena between thermophilic Naegleria strains.     

Total gaseous mercury in the atmosphere of Guiyang,PR China

Four measurement campaigns were carried out to monitor total gaseous mercury (TGM) at one site in the Guiyang City, PR China in the following periods: April 19-30, 2000; February 26-March 14, 2001; June 26-July 20, 2001; and October 9-November 22, 2001, respectively. High temporal resolved data were obtained by using automated mercury analyzers Gardis 1A and Tekran 2537A. TGM data from all measurement periods followed the typical log normal distribution pattern. The geometric mean of TGM from different seasons were 8.56, 7.45, 5.20 and 8.33 ngm(-3) in spring 2000, winter 2001, summer 2001 and autumn 2001, respectively. The overall average TGM covering the sampling periods was 7.39 ngm(-3), which is significantly elevated comparing to global background of approximately 1.5-2.0 ngm(-3). The major anthropogenic atmospheric mercury emission sources differed significantly among seasons, which caused the seasonal variability of TGM level. Distinct daily variability of TGM was observed among seasons. The daytime TGM concentrations were larger than that of nighttime in spring and winter seasons, while in summer and autumn the opposite daily TGM distribution pattern was observed.     

Virus induces metal-binding proteins and changed trace element balance in the brain during the course of a common human infection (coxsackievirus B3) in mice

Autopsy of the brain has shown a change in trace element balance in some virus-infected individuals, but it is not known whether this event was a result of the infection. In the present study coxsackievirus B3 (CVB3) adapted to Balb/c mice was used to study whether infection induces gene expression of the metal-binding/transporting proteins metallothionein (MT1 and MT3) and divalent-metal transporter 1 (DMT1) and whether it changes the balance of trace elements in the brain. Virus and MT1, MT3, and DMT1 were quantitatively measured by RT-PCR on days 3, 6 and 9 of the infection. Trace elements (13) were measured in serum and the brain by ICP-MS. High numbers of virus were found in the brain on days 3 and 6, but virus counts were decreased and present only in 50% of the mice on day 9. Gene expression of MT1 tended to increase on all days, whereas that of MT3 only showed a minor and not significant increase on day 3. No clear effect was observed in the expression of DMT1. The increase of MT3 was correlated to the brain concentration of Cu. The Cu/Zn ratio in serum increased as a response to the infection. There was a similar decrease in Cd in serum and the brain. On day 6 of the infection, Hg increased in the brain (p<0.05) and was positively correlated to a concomitant decrease (p<0.05) in serum. Virus numbers in the brain were on day 6 positively correlated (p<0.05) to As concentrations. Enteroviral infections may therefore be an underlying factor regarding the changes in essential as well as potentially toxic trace elements in the brain.     

Race to the top in traffic calming

We study the competition of two suburbs facing transit traffic flows. The suburbs are substitutes for transit traffic. In the absence of toll measures, the symmetric Nash equilibrium with two local governments leads to a race to the top in traffic calming measures that increases the cost of travel. The Nash equilibrium is compared to two types of centralized decisions: the symmetric solution and the asymmetric solution. The asymmetric solution that concentrates all transit traffic in one suburb is better but can only be realized if the authority over the local roads is transferred to the central authority.     

The influence of training on the accuracy of roentgenographic cephalometric tracings (author's transl)

The accuracy in landmark identification and in the determination of angular and linear measurements used in cephalometric analysis on lateral head film were statistically evaluated comparing operators with different levels of competence. The observed magnitude of methodological error was depending on - prior experience of the investigator - individual radiographic anatomical knowledge - rigour of landmark definition and - accuracy of the tracing procedure. Considering these sources of error some of the variability in the present investigation might be avoided by systematic instructions. In order to decrease the variation in landmark location the reproducibility of some points must be further improved by redefining them in their verbal assessments. From an educational point of view the correlation between individual radiographic anatomical knowledge and the magnitude of error in cephalometric analysis should be considered with particular emphasis.