Extremal Results for Peg Solitaire on Graphs

In a 2011 paper by Beeler and Hoilman, the game of peg solitaire is generalized to arbitrary boards. These boards are treated as graphs in the combinatorial sense. An open problem from that paper is to determine the minimum number of edges necessary for a graph with a fixed number of vertices to be solvable. This thesis provides new bounds on this number. It also provides necessary and sufficient conditions for two families of graphs to be solvable, along with criticality results, and the maximum number of pegs that can be left in each of the two graph families

MARKET SEGMENTATION PRACTICES OF RETAIL CROP INPUT FIRMS

While market segmentation and the associated idea of target marketing are not new, there are questions about how the strategy of market segmentation and target marketing is being used in retail agribusiness firms. Previous research has demonstrated that distinct groups of farmers/customers exist (Alexander). However, retail crop input firms tend to be of modest size and are geographically bound. Both lack of resources and confinement to a specific geographic market present challenges for successful implementation of a market segmentation/target marketing strategy (Stolp). In this study, market segmentation/target marketing practices were explored in two types of crop input retailers: independently owned and operated firms (9 firms) and agricultural cooperatives (11 firms). A number of questions related to market segmentation/target marketing strategy were assessed via a web-based survey and telephone interviews. Referencing Best's seven-step framework, market segmentation is compared and contrasted by firm type; gaps in market segmentation strategy execution are identified; and challenges to implementing a market segmentation strategy are considered. Results show that market segmentation/target marketing was employed by 85% of the crop input retailers in the sample. Key gaps identified in market segmentation strategy execution include measuring market segment attractiveness; evaluating market segment profitability; developing a product-price positioning strategy for a tailored offering; expanding the positioning strategy to include promotional and sales elements of the marketing-mix; and evaluating the progress/success with each target market segment. Addressing these key gaps will aid industry professionals as they work to serve the needs of a continuously evolving farmer/customer base.market segmentation, target marketing, crop inputs, distribution channel, retailer

Innovativeness and Innovation: Implications for the Renewable Materials Supply Chain

innovativeness, innovation, supply chain management, triple bottom line, corporate social responsibility, Agribusiness, Agricultural Finance, Demand and Price Analysis, Financial Economics, Q10, Q27, Q42, Q47,

Resistance to Bt Corn by Western Corn Rootworm (Coleoptera: Chrysomelidae) in the U.S. Corn Belt

Transgenic Bt corn hybrids that produce insecticidal proteins from the bacterium Bacillus thuringiensis Berliner have become the standard insect management tactic across the U.S. Corn Belt. Widespread planting of Bt corn places intense selection pressure on target insects to develop resistance, and evolution of resistance threatens to erode benefits associated with Bt corn, such as reduced reliance on conventional insecticides. Recognizing the threat of resistance, the U.S. Environmental Protection Agency requires seed companies to include an insect resistance management (IRM) plan when registering a Bt trait. The goal of IRM plans is to delay Bt resistance in populations of target insects. One element of IRM is the presence of a non-Bt refuge to maintain Bt-susceptible individuals within a population, and growers are required to implement IRM on-farm by planting a refuge. Field-evolved resistance has not been detected for the European corn borer, Ostrinia nubilalis (Hubner), even though this species has been exposed to Bt proteins common in U.S. corn hybrids since 1996. The IRM situation is unfolding differently for Bt corn targeting the western corn rootworm, Diabrotica virgifera virgifera LeConte. In this article, we examine the scientific evidence for D. v. virgifera resistance to Bt rootworm traits and the cropping system practices that have contributed to the first reports of field-evolved resistance to a Bt toxin by D. v. virgifera. We explain why this issue has developed, and emphasize the necessity of an integrated pest management approach to address the issue

Kinetic Analysis of Lower Body Resistance Training Exercises

This study evaluated and compared the peak vertical ground reaction force (GRF) and rate of force development (RFD) for the eccentric and concentric phases of 4 lower body resistance training exercises, including the back squat, deadlift, step-up, and forward lunge. Sixteen women performed 2 repetitions of each of the 4 exercises at a 6 repetition maximum load. Kinetic data were acquired using a force platform. A repeated measures ANOVA was used to evaluate the differences in GRF between the exercises. Results revealed significant main effects for GRF both the eccentric (p ≤ 0.001) and concentric (p ≤ 0.001) phases. Significant main effects were also found for RFD for the eccentric (p ≤ 0.001) and concentric phases (p ≤ 0.001). Force and power requirements and osteogenic potential differ between these resistance training exercises

Effect of Bt Maize and Soil Insecticides on Yield, Injury, and Rootworm Survival: Implications for Resistance Management

A 2-yr field experiment was conducted to determine the effects on Diabrotica spp. (Coleoptera: Chrysomelidae) of an insecticidal seed treatment (Poncho 1250, (AI) /clothianidin) and a granular insecticide (Aztec 2.1G, (AI)/tebupirimphos and cyfluthrin) alone and in combination with maize producing the insectidical toxin Cry3Bb1 derived from the bacterium Bacillus thuringiensis (Bt). Yields for Bt maize plots were significantly greater than for non-Bt maize; however, insecticides did not significantly affect yield. Insecticides significantly decreased root injury in non-Bt maize plots, but there were no significant differences in root injury between Bt maize with or without either insecticide. Maize producing the Bt toxin Cry3Bb1 and the soil-applied insecticide Aztec significantly decreased survival of western corn rootworm (Diabrotica virgifera virgifera LeConte), while only Bt maize significantly decreased survival of the northern corn rootworm (Diabrotica barberi Smith & Lawrence). For both species, Bt maize and each of the insecticides delayed emergence. In the absence of density-dependent mortality, Bt maize imposed 71 and 80% reduction in survival on the western corn rootworm and the northern corn rootworm, respectively. The data from this study do not support combining insecticide with Bt maize because the addition of insecticide did not increase yield or reduce root injury for Bt maize, and the level of rootworm mortality achieved with conventional insecticide was likely too low to delay the evolution of Bt resistance. In addition, delays in emergence from Bt maize combined with insecticides could promote assortative mating among Bt-selected individuals, which may hasten resistance evolution

Antagonist conditioning contractions impair agonist functioning

This study assessed the effect of antagonist conditioning contractions (ACC) on the subsequent force and electromyography of an agonist. Twelve subjects performed isokinetic elbow flexion on a dynamometer in 4 test conditions including a baseline condition without, and 1, 3 and 6 seconds after, isometric triceps extension. Average peak torque (T), peak torque/body weight (T:BW), average power (P), and rate of torque development (RTD) were assessed. Electromyographic data were obtained from elbow extensors and flexors. A repeated measures ANOVA with post hoc analysis demonstrated that T, T:BW, P, and RTD were higher in the baseline, compared to the post ACC conditions (P ≤ 0.05), and appears to be due to higher brachioradialis activation in the baseline condition in compared to some post ACC conditions (P ≤ 0.05)

Optimizing Compton Back Scattering Parameters Using a Simulation Code

Compton scattering is an interaction of photons with atomic electrons, in which both the energy and the momentum are conserved. The photon interacts with a constant interaction cross section per electron eσc for all materials at a certain photon energy. However the Compton scattering cross section per atom, σc, is equal to the number of electrons in the atom multiplied by the eσc [1]: σc=Zeσc this characteristic means that for a given photon energy, each material has a unique scattering cross section different from other materials. It also means that the higher the atomic number, the stronger the signal obtained from Compton scattering, at least for small thicknesses