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With the advent of sustainable building ordinances in the United States and internationally, contractors are required to deliver sustainable projects but have historically not been considered partners in developing the sustainability goals and objectives for projects. Additionally, as alternative project delivery methods gain popularity, contractors have an opportunity and—in an increasing number of cases—a requirement, to take a larger role in sustainability efforts beyond the design phase. Understanding the contractor’s self-perceived role in this industry is imperative to informing their future role in the sustainable construction industry. This paper presents data and analysis of a survey of general contractors in the Phoenix, Arizona market that asked for their opinions and viewpoints regarding sustainable construction. Respondents provided feedback about corporate profitability, growth forecast, and the perceived efficiency of the U.S Green Building Council’s LEED rating system. The survey also queried contractors about current and future work breakdown structures for sustainable project delivery as well as their underlying motives for involvement in these projects.
Academics from Arizona State University worked with local industry to develop the survey in 2012 and the survey was deployed in 2013. We sent the survey to 76 contractors and received responses from 21, representing a 27.6% response rate. Respondents include representatives from general contractors, mechanical contractors, and electrical contractors, among others. This paper presents the responses from general contractors as they typically have most contact with the owner and design teams.
Five immunocompetent C57BL/6-cBrd/cBrd/Cr (albino C57BL/6) mice were injected with GL261-luc2 cells, a cell line sharing characteristics of human glioblastoma multiforme (GBM). The mice were imaged using magnetic resonance (MR) at five separate time points to characterize growth and development of the tumor. After 25 days, the final tumor volumes of the mice varied from 12 mm3 to 62 mm3, even though mice were inoculated from the same tumor cell line under carefully controlled conditions. We generated hypotheses to explore large variances in final tumor size and tested them with our simple reaction-diffusion model in both a 3-dimensional (3D) finite difference method and a 2-dimensional (2D) level set method. The parameters obtained from a best-fit procedure, designed to yield simulated tumors as close as possible to the observed ones, vary by an order of magnitude between the three mice analyzed in detail. These differences may reflect morphological and biological variability in tumor growth, as well as errors in the mathematical model, perhaps from an oversimplification of the tumor dynamics or nonidentifiability of parameters. Our results generate parameters that match other experimental in vitro and in vivo measurements. Additionally, we calculate wave speed, which matches with other rat and human measurements.