The valuation of travel time savings in least developed countries:theoretical and empirical challenges and results from a field study

In developed countries travel time savings can account for as much as 80% of the overall benefits arising from transport infrastructure and service improvements. In developing countries they are generally ignored in transport project appraisals, notwithstanding their importance. One of the reasons for ignoring these benefits in the developing countries is that there is insufficient empirical evidence to support the conventional models for valuing travel time where work patterns, particularly of the poor, are diverse and it is difficult to distinguish between work and non-work activities. The exclusion of time saving benefits may lead to a bias against investment decisions that benefit the poor and understate the poverty reduction potential of transport investments in Least Developed Countries (LDCs). This is because the poor undertake most travel and transport by walking and headloading on local roads, tracks and paths and improvements of local infrastructure and services bring large time saving benefits for them through modal shifts. The paper reports on an empirical study to develop a methodology for valuing rural travel time savings in the LDCs. Apart from identifying the theoretical and empirical issues in valuing travel time savings in the LDCs, the paper presents and discusses the results of an analysis of data from Bangladesh. Some of the study findings challenge the conventional wisdom concerning the time saving values. The Bangladesh study suggests that the western concept of dividing travel time savings into working and non-working time savings is broadly valid in the developing country context. The study validates the use of preference methods in valuing non-working time saving values. However, stated preference (SP) method is more appropriate than revealed preference (RP) method.

Time and professional work in public sector organisations: an examination of four occupational groups in education and medicine

The aim of this thesis is to examine the experience of time of four professional occupational groups working in public sector organisations and the factors affecting this experience. The literature on time and work is examined to delineate the key parameters of research in this area. A broad organisation behaviour approach to the experience of time and work is developed in which individual, occupational, organisational and socio-political factors are inter-related. The experience of secondary school teachers, further education lecturers, general medical practitioners and hosoital consultants is then examined. Multiple methods of data collection are used: open-ended interviews, a questionnaire survey and the analysis of key documents relating to the institutional settings in which the four groups work. The research aims to develop our knowledge of working time by considering the dimensions of the experience of time at work, the contexts in wlhich this experience is generated and the constraints these contexts give rIse to. By developing our understanding of time as a key feature of work experience we also extend our knowledge of organisation behaviour in general. In conclusion a model of the factors relating the experience of time to the negotiation of time at work is presented.

Development of a co-culture model of the human lungs for toxicity testing and identification of biomarkers of inhalation toxicity

The airway epithelium is the first point of contact in the lung for inhaled material, including infectious pathogens and particulate matter, and protects against toxicity from these substances by trapping and clearance via the mucociliary escalator, presence of a protective barrier with tight junctions and initiation of a local inflammatory response. The inflammatory response involves recruitment of phagocytic cells to neutralise and remove and invading materials and is oftern modelled using rodents. However, development of valid in vitro airway epithelial models is of great importance due to the restrictions on animal studies for cosmetic compound testing implicit in the 7th amendment to the European Union Cosmetics Directive. Further, rodent innate immune responses have fundamental differences to human. Pulmonary endothelial cells and leukocytes are also involved in the innate response initiated during pulmonary inflammation. Co-culture models of the airways, in particular where epithelial cells are cultured at air liquid interface with the presence of tight junctions and differentiated mucociliary cells, offer a solution to this problem. Ideally validated models will allow for detection of early biomarkers of response to exposure and investigation into inflammatory response during exposure. This thesis describes the approaches taken towards developing an in vitro epithelial/endothelial cell model of the human airways and identification biomarkers of response to exposure to xenobiotics. The model comprised normal human primary microvascular endothelial cells and the bronchial epithelial cell line BEAS-2B or normal human bronchial epithelial cells. BEAS-2B were chosen as their characterisation at air liquid interface is limited but they are robust in culture, thereby predicted to provide a more reliable test system. Proteomics analysis was undertaken on challenged cells to investigate biomarkers of exposure. BEAS-2B morphology was characterised at air liquid interface compared with normal human bronchial epithelial cells. The results indicate that BEAS-2B cells at an air liquid interface form tight junctions as shown by expression of the tight junction protein zonula occludens-1. To this author’s knowledge this is the first time this result has been reported. The inflammatory response of BEAS-2B (measured as secretion of the inflammatory mediators interleukin-8 and -6) air liquid interface mono-cultures to Escherichia coli lipopolysaccharide or particulate matter (fine and ultrafine titanium dioxide) was comparable to published data for epithelial cells. Cells were also exposed to polymers of “commercial interest” which were in the nanoparticle range (and referred to particles hereafter). BEAS-2B mono-cultures showed an increased secretion of inflammatory mediators after challenge. Inclusion of microvascular endothelial cells resulted in protection against LPS- and particle- induced epithelial toxicity, measured as cell viability and inflammatory response, indicating the importance of co-cultures for investigations into toxicity. Two-dimensional proteomic analysis of lysates from particle-challenged cells failed to identify biomarkers of toxicity due to assay interference and experimental variability. Separately, decreased plasma concentrations of serine protease inhibitors, and the negative acute phase proteins transthyretin, histidine-rich glycoprotein and alpha2-HS glycoprotein were identified as potential biomarkers of methyl methacrylate/ethyl methacrylate/butylacrylate treatment in rats.

Gesundheitsrisiken bei Unternehmern

An einer Studie zum Zusammenhang zwischen der Gesundheit von Unternehmern, deren Arbeitsmerkmalen und deren Erfolg nahmen 53 klein- und mittelständische Unternehmer teil. Erfasste Arbeitsmerkmale waren: Handlungs-/Entscheidungsspielraum, Arbeitsintensität, Arbeitszeit, Konkurrenzdruck und Prognose über die Auftragsentwicklung. Der Unternehmenserfolg wurde über das Mitarbeiterwachstum, die Möglichkeit des Unternehmers, von seiner Firma abwesend zu sein (Urlaubstage), und dem erlebten Unternehmenserfolg operationalisiert. Gesundheitsindikatoren waren Depression, Angst, vitale Erschöpfung, Schlafstörungen und Bluthochdruck. Im Vergleich zur Gesamtbevölkerung wiesen die Unternehmer in allen untersuchten Gesundheitsvariablen häufiger Beeinträchtigungen auf. Regressionsanalysen ergaben, dass lange Arbeitszeiten und Konkurrenzdruck mit einer verzögerten Rückstellung des systolischen Blutdrucks (SBD) in der Freizeit und Nacht einhergingen. Alle untersuchten Erfolgsmerkmale waren für die Gesundheit prädiktiv. So war Mitarbeiterwachstum negativ mit dem SBD während der Arbeit sowie Schlafstörungen assoziiert. Je mehr Unternehmenserfolg erlebt wurde, desto geringer waren die Werte für vitale Erschöpfung und Depression. Die Urlaubsdauer war negativ mit Angst und vitaler Erschöpfung korreliert. Insgesamt hatte von den Arbeitsmerkmalen nur die Dauer der Arbeitszeit einen Effekt auf die Gesundheit von Unternehmern. Daneben existieren aber offensichtlich weitere Faktoren, die mit der Unternehmergesundheit in Beziehung stehen. Dies sind neben dem Konkurrenzdruck am Markt insbesondere Indikatoren des Unternehmenserfolgs. The relationship between health and workload as well as entrepreneurial success was analyzed in 53 entrepreneurs. Workload data (decision latitude, job demand, working time, competition, market development) were determined by using structured interviews and Karasek's job content questionnaire. Firm success was operationalized by employee growth, the possibility of absence from the company (days of holiday), and perceived success. Health was measured by questionnaires for sleep disturbances, vital exhaustion, depression, and anxiety, and by 24 hour ambulatory blood pressure monitoring. Regression analyses showed that working time and strength of competition within the market were predictive for systolic blood pressure (SBP) during leisure time and night, but not during work. All variables measuring entrepreneurial success were predictive for health. Employee growth was related to decreasing SBP during work and to fewer sleep disturbances. The duration of holidays was negatively related to vital exhaustion and anxiety. Perceived company success was negatively related to depression and vital exhaustion. In conclusion, only the relationship between working time and bad health conformed to findings reported for the relationship between work and health in employees. However, there were additional indicators, especially indicators of competition and entrepreneurial success, that affected the health of entrepreneurs.

Determining the number of nodes for wireless sensor networks

The number of nodes has large impact on the performance, lifetime and cost of wireless sensor network (WSN). It is difficult to determine, because it depends on many factors, such as the network protocols, the collaborative signal processing (CSP) algorithms, etc. A mathematical model is proposed in this paper to calculate the number based on the required working time. It can be used in the general situation by treating these factors as the parameters of energy consumption. © 2004 IEEE.