Real Wage Determinatioan in Collective BArgaining Agreements

This paper studies the determinants of real wage rates using data on Canadian labour contracts signed between 1978 and 1984. Its results are consistent with Dunlop's neglected (1944) hypothesis that real pay movements are shaped by product price changes (contrary to the predictions of implicit contract theory and other models of wage inflexibility). The level of the unemployment rate is found to lower the real wage level with an elasticity between -0.04 and -0.13, whereas a Phillips Curve specification which relates wage changes to the level of the unemployment rate is not convincingly supported by the data. These results may be seen as consistent with the view that collective bargaining is a form of rent-sharing in which external unemployment weakens workers' bargaining strength.

Disrupted Capacitated Vehicle Routing Problem with Order Release Delay

With the popularity of the just-in-time system, more and more companies are operating with little or no inventories, which make them highly vulnerable to delays on supply. This paper discusses a situation when the supply of the commodity does not arrive at the depot on time, so that not enough of the commodity is available to be loaded on all vehicles at the start of the delivery period. New routing plans need to be developed in such a case to reduce the impact the delay of supply may have on the distribution company. The resulting vehicle routing problem is different from other types of vehicle routing problems as it involves waiting and multiple trips. Two approaches have been developed to solve the order release delay problem, both of which involve a Tabu Search algorithm. Computational results show the proposed approaches can largely reduce the disruption costs that are caused by the delayed supply and they are especially effective when the length of delay is long

Efficient and Inefficient Employment Outcomes: A Study Based on Canadian Data

This paper estimates employment equations based on the traditional labour demand model and modern efficient bargain theory using data drawn from wage contracts signed in the Canadian private unionized sector between 1978 and 1984. Contrary to the labour demand model predictions, the alternative wage rate is consistently significant and has the negative coefficient predicted by efficient bargain theory. Though a credible labour demand model can sometimes be estimated, the results are sensitive to the assumed market structure and to the introduction of alternative wage and unemployment insurance variables. Non-nested tests favour efficient bargain specifications.

Comparative study of the environmental footprints of marinas on European Islands

Ports have been key elements in Europe's economic development. This situation is even more relevant on islands, which are highly dependent on the maritime sector. Consequently, over the years, ports with diverse functionalities have been established both in mainland Europe and on its outlying islands. This article discusses the environmental impact of leisure marinas on European islands, especially as they are closely linked to economic development through tourism. The aim is to study the environmental impact of these infrastructures by determining the carbon and water footprints of marinas on European islands in the Atlantic and the Mediterranean. The results obtained enable the authors to make recommendations in order to reduce the overall environmental footprint of marinas on islands, considering that these territories are much more vulnerable to climate change than mainland locations in Europe

Evidence for high sugar content of baby foods in South Africa

Background. Early-life exposure to excess sugar affects eating behaviour and creates a predisposition to non-communicable diseases (NCDs). While reducing sugar consumption has been high on the public health agenda, little is known about the sugar content of baby foods.Objectives. To describe and analyse the sugar content of baby foods in South Africa (SA).Methods. A cross-sectional study was conducted to analyse the sugar content of baby foods. The study sample included commercially available baby foods targeted at children aged <12 months, sold in supermarkets and by other major retailers in SA. Primary data were obtained from the packaging, and sugar content was compared with recommended intake guidelines. Bivariate analyses were conducted to determine whether there were any associations between the sugar content, added sugar and the characteristics of foods.Results. Over 70% of products were sweet in taste, with one in four containing added sugars. Sugar content was high in 78% of the foods sampled. Over 80% of cereals and pureed desserts contained added sugar. Fewer than 10% of pureed composite meal and pureed fruit and vege­table categories contained added sugar. Most products adhered to SA labelling standards, but none had front-of-pack nutritional information.Conclusions. The SA baby food market is characterised by products with a high sugar content, promoting an environment that encourages development of sweet-taste preferences and in the long term contributing to the rising burden of NCDs. There is an urgent need for mandatory regulation of sugar in baby foods.

Exploring Graphs with Time Constraints by Unreliable Collections of Mobile Robots

A graph environment must be explored by a collection of mobile robots. Some of the robots, a priori unknown, may turn out to be unreliable. The graph is weighted and each node is assigned a deadline. The exploration is successful if each node of the graph is visited before its deadline by a reliable robot. The edge weight corresponds to the time needed by a robot to traverse the edge. Given the number of robots which may crash, is it possible to design an algorithm, which will always guarantee the exploration, independently of the choice of the subset of unreliable robots by the adversary? We find the optimal time, during which the graph may be explored. Our approach permits to find the maximal number of robots, which may turn out to be unreliable, and the graph is still guaranteed to be explored. We concentrate on line graphs and rings, for which we give positive results. We start with the case of the collections involving only reliable robots. We give algorithms finding optimal times needed for exploration when the robots are assigned to fixed initial positions as well as when such starting positions may be determined by the algorithm. We extend our consideration to the case when some number of robots may be unreliable. Our most surprising result is that solving the line exploration problem with robots at given positions, which may involve crash-faulty ones, is NP-hard. The same problem has polynomial solutions for a ring and for the case when the initial robots' positions on the line are arbitrary. The exploration problem is shown to be NP-hard for star graphs, even when the team consists of only two reliable robots

Advanced perception, navigation and planning for autonomous in-water ship hull inspection

Inspection of ship hulls and marine structures using autonomous underwater vehicles has emerged as a unique and challenging application of robotics. The problem poses rich questions in physical design and operation, perception and navigation, and planning, driven by difficulties arising from the acoustic environment, poor water quality and the highly complex structures to be inspected. In this paper, we develop and apply algorithms for the central navigation and planning problems on ship hulls. These divide into two classes, suitable for the open, forward parts of a typical monohull, and for the complex areas around the shafting, propellers and rudders. On the open hull, we have integrated acoustic and visual mapping processes to achieve closed-loop control relative to features such as weld-lines and biofouling. In the complex area, we implemented new large-scale planning routines so as to achieve full imaging coverage of all the structures, at a high resolution. We demonstrate our approaches in recent operations on naval ships.United States. Office of Naval Research (Grant N00014-06-10043)United States. Office of Naval Research (Grant N00014-07-1-0791

AIDSImpact special issue: pathways to transactional sex among peri-urban South African women: the role of relationship control, food insecurity and alcohol misuse

This is the final version. Available on open access from Taylor & Francis via the DOI in this recordTransactional sex increases sub-Saharan African women's risk of HIV acquisition. We quantitatively explored the pathways contributing towards women's future engagement in transactional sex with casual partners and khwapheni (secret concurrent sex partners). We conducted secondary data analysis from a cluster randomised controlled trial in urban informal settlements in eThekwini Municipality., South Africa. Data were collected at enrolment (t0) and 24 months' later (t2) using self-completed questionnaires. Structural equation modelling (SEM) assessed pathways leading to transactional sex over two years. 677 women 18-35 years were enrolled and 80.5% (n = 545) were followed up. At t2, 44.6% of respondents reported transactional sex with a casual partner or khwapheni. The SEM demonstrated a small effect (d = 0.23) between transactional sex at t0 and at t2. Controlling for past transactional sex, main partner relationship control had a large effect size on future transactional sex (d = 0.60). Hazardous drinking had a medium effect size (d = 0.45) and food insecurity a small effect (d = 0.24), (RMSEA 0.03, 90%CI 0.02-0.04; CFI 0.97; TLI 0.96). HIV prevention programming should highlight current transactional sex but also address structural issues predicting future transactional sex, including food insecurity and alcohol misuse. Gender transformative interventions to reduce controlling behaviours in main relationships are worth investigating.UK Department for International Developmen

Male perspectives on intimate partner violence: A qualitative analysis from South Africa

Background Intimate partner violence (IPV) affects one in four women globally and is more commonly enacted by men than women. Rates of IPV in South Africa exceed the global average. Exploring the background and context regarding why men use violence can help future efforts to prevent IPV. Methods We explored adult men’s perspectives of IPV, livelihoods, alcohol use, gender beliefs, and childhood exposure to abuse through a secondary analysis of qualitative interviews that were conducted in South Africa. The setting was a peri-urban township characterized by high unemployment, immigration from rural areas, and low service provision. We utilized thematic qualitative analysis that was guided by the social ecological framework. Results Of 30 participants, 20 were residents in the neighborhood, 7 were trained community members, and 3 were program staff. Men reported consumption of alcohol and lack of employment as being triggers for IPV and community violence in general. Multiple participants recounted childhood exposure to abuse. These themes, in addition to culturally prescribed gender norms and constructs of manhood, seemed to influence the use of violence. Conclusion Interventions aimed at reducing IPV should consider the cultural and social impact on men’s use of IPV in low-resource, high-IPV prevalence settings, such as peri-urban South Africa. This work highlights the persistent need for the implementation of effective primary prevention strategies that address contextual and economic factors in an effort to reduce IPV that is primarily utilized by men directed at women

Bun splitting: a practical cutting stock problem

We describe a new hierarchical 2D-guillotine Cutting Stock Problem. In contrast to the classic cutting stock problem, waste is not an issue. The problem relates to the removal of a defective part and assembly of the remaining parts into homogeneous size blocks. The context is the packing stages of cake manufacturing. The company's primary objective is to minimise total processing time at the subsequent, packing stage. This objective reduces to one of minimising the number of parts produced when cutting the tray load of buns. We offer a closed form optimization approach to this class of problems for certain cases, without recourse to mathematical programming or heuristics. The methodology is demonstrated through a case study in which the number of parts is reduced by almost a fifth, and the manufacturer's subsidiary requirement to reduce isolated single bun parts and hence customer complaints is also satisfied