Reshaping Platform-Driven Digital Markets

The market size and strength of the major digital platform companies has invited international concern about how such firms should best be regulated to serve the interests of wider society, with a particular emphasis on the need for new antitrust legislation. Using a normative innovation systems approach, this chapter investigates how current antitrust models may insufficiently address the value-extracting features of existing data-intensive and platform-oriented industry behaviour and business models. To do so, it employs the concept of economic rents to investigate how digital platforms create and extract value. Two forms of rent are elaborated: ‘network monopoly rents’ and ‘algorithmic rents’. By identifying such rents more precisely, policymakers and researchers can better direct regulatory investigations, as well as broader industrial and innovation policy approaches, to shape the features of platform-driven digital markets

Hydrologic Niches Explain Species Coexistence and Abundance in a Shrub-Steppe System

Differences in vertical root distributions are often assumed to create resource uptake tradeoffs that determine plant growth and coexistence. Yet, most plant roots are in shallow soils, and data linking root distributions with resource uptake and plant abundances remain elusive. Here we used a tracer experiment to describe the vertical distribution of absorptive roots of dominant species in a shrub‐steppe ecosystem. To describe how these different rooting distributions affected water uptake in wet and dry soils across a growing season, we used a soil water movement model. Root traits were then correlated with plant landscape abundances. Deeper root distributions extracted more soil water, had larger unique hydrological niches and were more abundant on the landscape. Though most (\u3e 50%) root biomass and tracer uptake occurred in shallow soils (0–32 cm), the depth of 50% of tracer uptake varied from 11 to 32 cm across species and species with deeper rooting distributions were more abundant on the landscape (R2 = 0.95). The water flow model revealed that deeper rooting distributions should extract more soil water (i.e., a range of 60 to 113 mm of soil water) because shallow roots were often in dry soils. These potential water uptake values were tightly correlated with species’ abundances on the landscape (R2 = 0.90). Finally, each species’ rooting distribution demonstrated a depth and time at which it could extract more soil water than any other rooting distribution, and the size of these unique hydrological niches indices was also well correlated with species’ abundances (R2 = 0.89). Synthesis. Our results demonstrate not only a correlation between root distributions and species abundance, but also the mechanism through which differences in rooting distributions can determine resource uptake and niche partitioning, even when most roots are found in shallow soils

270717.qxd

Abstract Community assembly rules are often inferred from patterns in presence-absence matrices. A challenging problem in the analysis of presence-absence matrices has been to devise a null model algorithm to produce random matrices with fixed row and column sums. Previous studies by Roberts and Stone [(1990) Oecologia 83:560-567] and Manl

Stereotype threat : a qualitative study of the challenges facing female undergraduate engineering students

Advisors: Elizabeth A. Wilkins.Committee members: Daryl Dugas; Nicole Ladue.Includes bibliographical references.From a sociocultural point of view, this qualitative case study explored how upper-level, female undergraduate engineering students perceived the possibility of or experience with stereotype threat as shaping their experiences. The study also investigated how these students explained their reasons for choosing their engineering major, the challenges they encountered in the major, and their reasons for persevering in spite of those challenges. Using Steele and Aronson's (1995) stereotype threat theory as a framework, and considering the documented underrepresentation of females in engineering, the study sought to examine how stereotype threat shaped the experiences of these students and if stereotype threat could be considered a valid reason for the underrepresentation. The study was conducted at a large, four-year public university. First, students in the College of Engineering and Engineering Technology completed the Participant Screening Survey. Based on responses from the survey, six female engineering students from the college were identified and invited to participate in the study. The participants came from the following majors: Electrical Engineering, Industrial and Systems Engineering, and Mechanical Engineering. After receiving the study consent letter and agreeing to participate, the students were involved in a 90-minute focus group meeting, a 45-minute one-on-one interview, and a 30-minute follow-up interview. After conducting the data collection methods, the data were then transcribed, analyzed, and coded for theme development. The themes that emerged coincided with each research question. The themes highlighted the complex interactions and experiences shared by the female engineering majors. The female students were enveloped in an environment where there existed an increased risk for activating stereotype threat. In addition, the female students described feeling pushed to prove to themselves and to others that the negative stereotype that 'females are bad at engineering' was untrue. The findings illustrated the need for systematic changes at the university level. Intervention recommendations were provided. In regards to female underrepresentation in science fields, including engineering, stereotype threat certainly had the potential to cause the female students to question themselves, their abilities, their choice of an academic major, and subsequently remove themselves from a hostile learning or working environment. Thus, educational institutions and workplace organizations are responsible for not only educating themselves regarding stereotype threat, but also for taking steps to alleviate the pernicious effects of stereotype threat.Ed.D. (Doctor of Education

PRODUCTION OF YELLOW POPLAR INTERIOR PLYWOOD WITH COTTONSEED-BASED PROTEIN ADHESIVES

Defatted cottonseed (CS) and water-washed CS meals were prepared from glandless CS and were used in adhesive formulations to produce three-ply yellow poplar plywood panels. Adhesive resins were prepared from each protein meal with sodium bisulfite and one of two polyamido-amine-epichlorohydrin (PAE) wet strength agents, and the plywood panels were produced by hot pressing. Shear strength and water resistance were determined by American Society of Testing and Materials (ASTM) and American National Standards Institute for Hardwood and Decorative Plywood/Hardwood Plywood and Veneer Association (ANSI/HPVA) methods and were compared with the properties of plywood panels made with an adhesive formulated from a commercial soybean meal. Panels prepared from three protein meals had comparable shear strengths. The combinations of the two CS preparations and the two wet strength agents produced panels with acceptable wet resistant properties, whereas the soybean meal only produced acceptable panels with one of the wet strength agents. Because the panels prepared from the two CS meals had comparable properties, there appears to be no benefit to including a water-washing step to increase the meal’s protein level. In contrast with recent literature reports suggesting the addition of alkali to elevate the formulation pH was necessary with CS meal, suitable panels were prepared herein without the addition of the base. This difference may have been due to the slightly higher pressing temperature and longer press times used in this work compared with earlier results. The CS meals showed promise as formaldehyde-free hardwood-plywood wood-based adhesives for interior applications. 

Predicting continental-scale patterns of bird species richness with spatially explicit models

The causes of global variation in species richness have been debated for nearly two centuries with no clear resolution in sight. Competing hypotheses have typically been evaluated with correlative models that do not explicitly incorporate the mechanisms responsible for biotic diversity gradients. Here, we employ a fundamentally different approach that uses spatially explicit Monte Carlo models of the placement of cohesive geographical ranges in an environmentally heterogeneous landscape. These models predict species richness of endemic South American birds (2248 species) measured at a continental scale. We demonstrate that the principal single-factor and composite (species-energy, water-energy and temperature-kinetics) models proposed thus far fail to predict (r(2)⩽0.05) the richness of species with small to moderately large geographical ranges (first three range-size quartiles). These species constitute the bulk of the avifauna and are primary targets for conservation. Climate-driven models performed reasonably well only for species with the largest geographical ranges (fourth quartile) when range cohesion was enforced. Our analyses suggest that present models inadequately explain the extraordinary diversity of avian species in the montane tropics, the most species-rich region on Earth. Our findings imply that correlative climatic models substantially underestimate the importance of historical factors and small-scale niche-driven assembly processes in shaping contemporary species-richness patterns