Achieving excellence in lean implementation at construction companies - A case study from Brazil

Lean Construction has become a popular concept to improve performance and reduce costs in construction projects. Assessment tools and implementation strategies that focus on lean practices such as the Last Planner System, the use of Kanbans, the routine of Kaizens and, recently, the integration with information technology are also common. However, barriers to the wide adoption of lean principles remain and implementation challenges continue to intrigue scholars. Previous studies suggest that barriers to the successful implementation can be either political, economical, social and/or technical, with the focus on lack of knowledge about lean concepts, resistance to the required organisational culture change, and lack of support from top management. Few studies present the lean implementation process from the practitioners’ perspective. Using the narrative enquiry methodology, the authors aim to describe how a construction company from Brazil matured from the implementation of lean operational tools to achieve excellence in the lean culture and mindset. Key themes that emerge from this study for a successful lean construction journey are; effort to stabilise the environment, knowledge creation and management, transparency in the process to enable simplicity and shared understanding, and building trust for further growth.

Nestedness of Ectoparasite-Vertebrate Host Networks

Determining the structure of ectoparasite-host networks will enable disease ecologists to better understand and predict the spread of vector-borne diseases. If these networks have consistent properties, then studying the structure of well-understood networks could lead to extrapolation of these properties to others, including those that support emerging pathogens. Borrowing a quantitative measure of network structure from studies of mutualistic relationships between plants and their pollinators, we analyzed 29 ectoparasite-vertebrate host networks—including three derived from molecular bloodmeal analysis of mosquito feeding patterns—using measures of nestedness to identify non-random interactions among species. We found significant nestedness in ectoparasite-vertebrate host lists for habitats ranging from tropical rainforests to polar environments. These networks showed non-random patterns of nesting, and did not differ significantly from published estimates of nestedness from mutualistic networks. Mutualistic and antagonistic networks appear to be organized similarly, with generalized ectoparasites interacting with hosts that attract many ectoparasites and more specialized ectoparasites usually interacting with these same “generalized” hosts. This finding has implications for understanding the network dynamics of vector-born pathogens. We suggest that nestedness (rather than random ectoparasite-host associations) can allow rapid transfer of pathogens throughout a network, and expand upon such concepts as the dilution effect, bridge vectors, and host switching in the context of nested ectoparasite-vertebrate host networks