Reframing Agribusiness: Moving from Farm to Market Centric

Agribusiness is moving from farm to market centric, where effective activities anticipate and respond to customers, markets, and the systems in which they function. This evolution requires a broader conceptualization and more accurate definition, to convey a more dynamic, systemic, and integrative discipline, which increasingly is committed to value creation and the sustainable orchestration of food, fiber, and renewable resources. We discuss the forces driving this shift to the market, offer a new and more representative definition of agribusiness, provide models to illustrate some of the most compelling trends, and articulate key elements and implications of those models.agribusiness definition, conceptual models, market centric, market systems, Agribusiness, Marketing, Production Economics,

Filler bar heating due to stepped tiles in the shuttle orbiter thermal protection system

An analytical study was performed to investigate the excessive heating in the tile to tile gaps of the Shuttle Orbiter Thermal Protection System due to stepped tiles. The excessive heating was evidence by visible discoloration and charring of the filler bar and strain isolation pad that is used in the attachment of tiles to the aluminum substrate. Two tile locations on the Shuttle orbiter were considered, one on the lower surface of the fuselage and one on the lower surface of the wing. The gap heating analysis involved the calculation of external and internal gas pressures and temperatures, internal mass flow rates, and the transient thermal response of the thermal protection system. The results of the analysis are presented for the fuselage and wing location for several step heights. The results of a study to determine the effectiveness of a half height ceramic fiber gap filler in preventing hot gas flow in the tile gaps are also presented

Accounting Policy Similarity and Active vs. Passive Institutional Investors

I examine the differential effects of similarity in accounting policy disclosures by firms on investment by active and passive institutional investors. I develop a novel measure of accounting similarity based on the textual disclosure of firms’ accounting policies from their annual reports. I find that, among firms with less similar textual descriptions of their accounting policies, investment by active institutions is higher than that of passive institutional investors. This suggests that these investors have a real or perceived information advantage in investing in firms with less comparable accounting. To establish causality, I use a difference-in differences approach that relies on the plausibly exogenous introduction of an accounting rule change, which is likely to decrease accounting similarity, and the rule’s subsequent reversal. My paper offers novel evidence on an under-explored relation between the textual properties of accounting disclosures and investor preferences.PHDBusiness AdministrationUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/143913/1/reggie_1.pd

Macroscopic invisibility cloaking of visible light

Invisibility cloaks, which used to be confined to the realm of fiction, have now been turned into a scientific reality thanks to the enabling theoretical tools of transformation optics and conformal mapping. Inspired by those theoretical works, the experimental realization of electromagnetic invisibility cloaks has been reported at various electromagnetic frequencies. All the invisibility cloaks demonstrated thus far, however, have relied on nano- or micro-fabricated artificial composite materials with spatially varying electromagnetic properties, which limit the size of the cloaked region to a few wavelengths. Here, we report the first realization of a macroscopic volumetric invisibility cloak constructed from natural birefringent crystals. The cloak operates at visible frequencies and is capable of hiding, for a specific light polarization, three-dimensional objects of the scale of centimetres and millimetres. Our work opens avenues for future applications with macroscopic cloaking devices

How Principals Learn to Be Technology Leaders: A Critical Incident Qualitative Study

The purpose of this study is to investigate how principals learn to be technology leaders by examining the different ways principals learn and exploring the skills principals perceive are needed. The study also examines what principals do differently to develop a successful technology integration (or not). Using the critical incident method, 18 principals were interviewed from across the state. The in-depth interviews were transcribed for all participants interviewed and then analyzed using coding and theming with the aid of memos. From this, three predominant categories emerged: learning, skills, and challenges. The findings from the study reveal that principals learn primarily through three different methods, with the most important one being professional development. Professional development is through face-to-face or online learning using their professional learning networks to guide them in developing the needed knowledge. The principals also learn by talking with others and learning on their own. The three areas the principals use to learn are their experiences, initiative, and reflection, which align with the common areas found in adult learning. The skills principals use to be technology leaders were found to be consistent with the skills described in the ISTE framework for educational leaders. Furthermore, principals face certain challenges while trying to be technology leaders and to integrate technology. Lastly, principals distinguished what they did differently for a technology integration to be successful (or not). The study concludes that principals can learn to be technology leaders, by using the right tools and by developing the necessary skills to be successful. The findings revealed the need for professional development on technological tools to be purposeful and fit the different needs of principals and teachers. For a technology integration to be successful, the professional development should not be a one-time meeting, but ongoing in order to provide continuous support and guidance for principals and teachers. Also, districts should make principals aware of the skills listed by ISTE for principals to be technology leaders. For some, knowing the skills needed will help them transform into technology leaders, allowing them to guide teachers to understand what they need to do in the classroom to be successful

Multiple photosynthetic transitions, polyploidy, and lateral gene transfer in the grass subtribe Neurachninae

The Neurachninae is the only grass lineage known to contain C3, C4, and C3–C4 intermediate species, and as such has been suggested as a model system for studies of photosynthetic pathway evolution in the Poaceae; however, a lack of a robust phylogenetic framework has hindered this possibility. In this study, plastid and nuclear markers were used to reconstruct evolutionary relationships among Neurachninae species. In addition, photosynthetic types were determined with carbon isotope ratios, and genome sizes with flow cytometry. A high frequency of autopolyploidy was found in the Neurachninae, including in Neurachne munroi F.Muell. and Paraneurachne muelleri S.T.Blake, which independently evolved C4 photosynthesis. Phylogenetic analyses also showed that following their separate C4 origins, these two taxa exchanged a gene encoding the C4 form of phosphoenolpyruvate carboxylase. The C3–C4 intermediate Neurachne minor S.T.Blake is phylogenetically distinct from the two C4 lineages, indicating that intermediacy in this species evolved separately from transitional stages preceding C4 origins. The Neurachninae shows a substantial capacity to evolve new photosynthetic pathways repeatedly. Enablers of these transitions might include anatomical pre-conditions in the C3 ancestor, and frequent autopolyploidization. Transfer of key C4 genetic elements between independently evolved C4 taxa may have also facilitated a rapid adaptation of photosynthesis in these grasses that had to survive in the harsh climate appearing during the late Pliocene in Australia

Evolution of Robustness to Noise and Mutation in Gene Expression Dynamics

Phenotype of biological systems needs to be robust against mutation in order to sustain themselves between generations. On the other hand, phenotype of an individual also needs to be robust against fluctuations of both internal and external origins that are encountered during growth and development. Is there a relationship between these two types of robustness, one during a single generation and the other during evolution? Could stochasticity in gene expression have any relevance to the evolution of these robustness? Robustness can be defined by the sharpness of the distribution of phenotype; the variance of phenotype distribution due to genetic variation gives a measure of `genetic robustness' while that of isogenic individuals gives a measure of `developmental robustness'. Through simulations of a simple stochastic gene expression network that undergoes mutation and selection, we show that in order for the network to acquire both types of robustness, the phenotypic variance induced by mutations must be smaller than that observed in an isogenic population. As the latter originates from noise in gene expression, this signifies that the genetic robustness evolves only when the noise strength in gene expression is larger than some threshold. In such a case, the two variances decrease throughout the evolutionary time course, indicating increase in robustness. The results reveal how noise that cells encounter during growth and development shapes networks' robustness to stochasticity in gene expression, which in turn shapes networks' robustness to mutation. The condition for evolution of robustness as well as relationship between genetic and developmental robustness is derived through the variance of phenotypic fluctuations, which are measurable experimentally.Comment: 25 page

Aging Logarithmic Conformal Field Theory : a holographic view

We consider logarithmic extensions of the correlation and response functions of scalar operators for the systems with aging as well as Schr\"odinger symmetry. Aging is known to be the simplest nonequilibrium phenomena, and its physical significances can be understood by the two-time correlation and response functions. Their logarithmic part is completely fixed by the bulk geometry in terms of the conformal weight of the dual operator and the dual particle number. Motivated by recent experimental realizations of Kardar-Parisi-Zhang universality class in growth phenomena and its subsequent theoretical extension to aging, we investigate our two-time correlation functions out of equilibrium, which show several qualitatively different behaviors depending on the parameters in our theory. They exhibit either growing or aging, i.e. power-law decaying, behaviors for the entire range of our scaling time. Surprisingly, for some parameter ranges, they exhibit growing at early times as well as aging at later times.Comment: 1+26 pages, 15 figure

Communications Biophysics

Contains research objectives and reports on three research projects.National Science Foundation (Grant G-16526)National Institutes of Health (Grant MH-04737-02