Quantifying urban forest structure,function, and value: the Chicago Urban Forest Climate Project

This paper is a review of research in Chicago that linked analyses of vegetation structure with forest functions and values. During 1991, the regions trees removed an estimated 5575 metric tons of air pollutants, providing air cleansing worth 9.2 million. Each year they sequester an estimated 315 800 metric tons of carbon. Increasing tree cover 10% or planting about three trees per building lot saves annual heating and cooling costs by an estimated 50 to 90 per dwelling unit because of increased shade, lower summertime air temperatures, and reduced neighborhood wind speeds once the trees mature. The net present value of the services trees provide is estimated as 402 per planted tree. The present value of long-term benefits is more than twice the present value of costs.     

The Production Function,Crop Diversity,and the Debate Between Conventional and Sustainable Agriculture1

Abstract Organizational assumptions embedded in the production function of neoclassical economics have served to structure production agriculture in the United States for the past 100 years. The narrow focus of the production function on the inputs of land, labor, capital, and management and the use of on-farm profitability as the primary definition of sustainability have come under attack from sustainable agriculturalists, who argue that the social and environmental consequences of production are as important as the economic outcomes. Using diversity of crops harvested as an indicator of sustainability, the production function is operationalized to inform the debate between the conventional, neoclassical model of production and the alternative, sustainable model. Census of agriculture data from 1978, 1982, and 1987 are used in both cross-sectional and temporal models. Results show that increases in expenditures for equipment and machinery, prevalence of corporate farms, higher rates of tenancy, and the prevalence of large farms are associated with lower levels of diversity at the county level. Conversely, higher levels of diversity are found in counties with greater farm labor expenses, where there are more medium-size farms, and where farmers are more likely to farm full-time.     

An Evaluation of the Rai and Van Ryzin Dose-Response Model in Teratology

The underlying assumptions of the Rai and Van Ryzin dose-response model for reproductive toxicological data are evaluated on the basis of existing experimental data. The model under consideration is unusual in its use of litter size to completely account for extra-binomial variation in the data by associating litter size with reproductive outcome. The experimental data show that controlling litter size is not sufficient to account for the litter-to-litter variability in responses. It is also shown that the two linear components of the Rai and Van Ryzin model are inappropriate. For the component which applies to the dam, the data suggest a strong nonlinearity, supported by rejection of the linear model via statistical hypothesis tests. In the component involving litter size, a relationship with dose is not apparent. The litter size parameters offer considerable potential for bias in estimation; bias which is at least partly masked by the model having good prediction characteristics due to the increased number of parameters. A simulation study is presented to illustrate how the Rai and Van Ryzin model can exaggerate litter size effects on the probability of response when the simulated data arise from a model involving a nonlinear dam component, common to this type of data, and no effect of litter size.     

Predicted outcomes in a national sample: A source of comparison for program evaluation

The lack of comparison groups is a common problem for researchers conducting evaluations of small, specialized programs. When conventional comparison groups are not available, the authors suggest a possible alternative approach which involves: (a) locating a sub-group in a national study for whom relevant variables have been measured; (b) generating a statistical model which predicts the outcome of interest in the national data; and (c) applying the predictive model to program data, in order to estimate outcomes in the absence of progam intervention. The authors illustrate this new application by presenting the results of an analysis of data from Project Talent, a national manpower study, and discuss its application to the evaluation of a medical training program in New York City.     

Re‐storying the Business,Innovation and Entrepreneurial Ecosystem Concepts: The Model‐Narrative Review Method

We propose a novel literature review method in order to systematically trace and reveal the dominant narratives of a body of literature: the model‐narrative review method. We apply this method to an ever‐growing literature on ecosystems in business studies, as it resembles a rich knowledge base with somewhat competing, overarching stories, replete with emplotted characters, systematic puzzles and embellished scientific drama. To interpret these unfolding storylines, we both separately engage with and connect seminal work on business, entrepreneurial and innovation ecosystems. Through thematic reading we map the key themes and scientific puzzles in each ecosystem type. Through enstoried reading we identify how authors construct the plot, narrative setting, emplotted characters, narrative voices and moral lessons around ecosystems. Through rhetorical reading we explicate the rhetorical devices and strategies that claim the relevance of their work. Our findings expose a number of hidden meanings and underlying assumptions, adding transparency to ecosystem rhetorics and enhancing conceptual clarity. Altogether, this method offers a systematic construction of model‐narratives to synthesize and critically reflect upon similarities and differences between related concepts and opens up space for alternative research questions.