IMPACTS OF GENETICALLY MODIFIED (GM) TRAITS ON CONVENTIONAL TECHNOLOGIES

In hard red spring (HRS) wheat, the two GM traits nearest to commercialization are fusarium resistant wheat (FRW) from Syngenta and Roundup Ready® wheat (RRW). Monsanto announced that it has deferred the commercialization of RRW until issues of market acceptance are alleviated. Monsanto acknowledged that it might reconsider its position if another agbiotechnology firm enters the GM wheat market. A Cournot quantity competition model was developed to determine the equilibrium quantities of conventional pesticide and agbiotechnology firms. The Cournot model was used because firms that must make production decisions ahead of the selling period, and firms with extensive research and development costs are not able to aggressively set prices. Rather, the conventional and agbiotechnology firms determine Nash equilibrium quantities and then determine a market clearing price for their respective products. The agbiotechnology firm determined a profit maximizing technology fee ($/acre) for its GM trait. The market with conventional wheat only was compared to the market with conventional and GM wheat varieties to determine the price decreases of the conventional pesticide as a result of the GM trait introduction. Changes in farmer surplus, tech firm payoffs, and sector welfare were also analyzed. Using the actual number of firms with conventional herbicides labeled for use on HRS wheat in North Dakota and marginal production costs ranging from one to three dollars, introduction of RRW would cause a 20-25% price decrease for conventional herbicides. Similarly, four firms produce conventional fungicides labeled for the suppression of FHB in HRS wheat. This value, combined with per acre marginal production costs ranging from one to three dollars, would likely cause a 19-22% price decrease for conventional fungicides, post introduction of GM FRW. Several implications arise from these results. First, adoption of a new GM wheat variety may not be as high as expected due to likely concurrent price decreases of conventional pesticides. The price decrease leads to a lower production cost of conventional varieties, and some farmers who would likely adopt the GM variety, if there were no price decrease, do not adopt because of the lower cost of conventional production. This price decrease must be included in the determination of potential adoption rates by agbiotechnology firms in their pricing decisions. Second, the release of a GM wheat variety results in an increase in surplus for all types of wheat farmers (GM adopters, conventional pesticide adopters, and no technology adopters). GM adopters benefit because of the release of the GM variety. Conventional pesticide adopters benefit due to the price decreases of the conventional pesticides. Farmers who did not adopt any technology prior to the release of GM wheat may adopt the conventional pesticide because of the lower cost. Third, the release of a GM wheat variety would result in slightly lower payoffs for conventional pesticide producing firms but higher payoffs for agbiotechnology firms. Overall, surplus to farmers and conventional and agbiotechnology firms increases due to the release of a GM wheat variety.genetic modification, fusarium resistance, Roundup Ready®, technology, Crop Production/Industries, Research and Development/Tech Change/Emerging Technologies,

STRATEGIC ANALYSIS OF TRAIT COMMERCIALIZATION IN GENETICALLY MODIFIED (GM) GRAINS: THE CASE OF GM WHEAT

The prospective commercialization of GM traits leads to several strategic questions for agbiotechnology and seed firms. Important issues addressed in this study include the method of trait commercialization by agbiotechnology firms and variety production decisions by seed firms. Specifically, agbiotechnology firms must decide whether to license their traits to seed firms, to purchase a seed firm, or to not license or release their traits. These issues are highly strategic. The purpose of this study was to determine equilibrium strategies of agbiotechnology and seed firms regarding the prospective commercialization of two GM traits. Two game theory models were developed to examine equilibrium strategies in two different scenarios. In the first model, both agbiotechnology firms had commercialization strategies of licensing and not licensing. In the second model, the first moving agbiotechnology firm was allowed to have a strategic option to purchase a seed firm as a commercialization strategy. The second agbiotechnology firm remained with two strategies, licensing and not licensing. These models were applied to the case of Roundup Ready® (RR) and fusarium resistant (FR) HRS wheat, although the general structure of the models could be used to analyze other crops and traits. Studies on trait commercialization and stacking are lacking the public literature. This study uses game theory models to develop likely situations that may occur regarding the prospective commercialization of GM traits.genetically modified grains, wheat, Crop Production/Industries, Research and Development/Tech Change/Emerging Technologies,

NASA Proof-of-Concept 1-W(sub e) Stirling Convertor Development for Small Radioisotope Power Systems

Low power Stirling convertors are being developed at NASA Glenn Research Center to provide future small spacecraft with electrical power by converting heat from one or more Light Weight Radioisotope Heater Units (LWRHU). An initial design converts multiple watts of heat to one watt of electrical power output using a Stirling convertor. A variety of mission concepts have been studied by NASA and the U. S. Department of Energy that would utilize low power Radioisotope Power Systems (RPS) for probes, landers, rovers, and repeaters. These missions would contain science instruments distributed across planetary surfaces or near objects of interest where solar flux is insufficient for using solar cells. Landers could be used to provide data such as, radiation, temperature, pressure, seismic activity, and other surface measurements for planetary science and to inform future mission planners. The studies propose using fractional versions of the General Purpose Heat Source or multiple LWRHUs to heat power conversion technologies for science instruments and communication. Dynamic power systems are capable of higher conversion efficiencies, which could enable equal power using less fuel or more power using equal fuel, when compared to less efficient static power conversion technologies. Providing spacecraft with more power would decrease duty cycling of basic functions and, therefore, increase the quality and abundance of science data. Efforts to develop the concept have focused on maturation of a 1-We convertor and controller design and performance evaluation of an evacuated metal foil insulation. A proof-of-concept 1-We convertor, controller, and evacuated metal foil insulation package have been fabricated and are undergoing characterization testing. The current status, findings, and path forward for the effort are explained in this paper

The central density of a neutron star is unaffected by a binary companion at linear order in μ/R\mu/R

Recent numerical work by Wilson, Mathews, and Marronetti [J. R. Wilson, G. J. Mathews and P. Marronetti, Phys. Rev. D 54, 1317 (1996)] on the coalescence of massive binary neutron stars shows a striking instability as the stars come close together: Each star's central density increases by an amount proportional to 1/(orbital radius). This overwhelms any stabilizing effects of tidal coupling [which are proportional to 1/(orbital radius)^6] and causes the stars to collapse before they merge. Since the claimed increase of density scales with the stars' mass, it should also show up in a perturbation limit where a point particle of mass $\mu$ orbits a neutron star. We prove analytically that this does not happen; the neutron star's central density is unaffected by the companion's presence to linear order in $\mu/R$. We show, further, that the density increase observed by Wilson et. al. could arise as a consequence of not faithfully maintaining boundary conditions.Comment: 3 pages, REVTeX, no figures, submitted to Phys Rev D as a Rapid Communicatio

Simulation and optimization of dynamic flux balance analysis models using an interior point method reformulation

This work presents a novel, differentiable, way of solving dynamic Flux Balance Analysis (dFBA) problems by embedding flux balance analysis of metabolic network models within lumped bulk kinetics for biochemical processes. The proposed methodology utilizes transformation of the bounds of the embedded linear programming problem of flux balance analysis via a logarithmic barrier (interior point) approach. By exploiting the first-order optimality conditions of the interior-point problem, and with further transformations, the approach results in a system of implicit ordinary differential equations. Results from four case studies, show that the CPU and wall-times obtained using the proposed method are competitive with existing state-of-the-art approaches for solving dFBA simulations, for problem sizes up to genome-scale. The differentiability of the proposed approach allows, using existing commercial packages, its application to the optimal control of dFBA problems at a genome-scale size, thus outperforming existing formulations as shown by two dynamic optimization case studies.• R. Conejeros would like to thank CONICYT’s research grant FONDECYT 1151295 for funding this research. • F. Scott gratefully acknowledges financial support from CONICYT (Proyectos REDES ETAPA INICIAL, Convocatoria 2017, REDI170254)

Anti-CD20 therapy depletes activated myelin-specific CD8+ T cells in multiple sclerosis.

CD8+ T cells are believed to play an important role in multiple sclerosis (MS), yet their role in MS pathogenesis remains poorly defined. Although myelin proteins are considered potential autoantigenic targets, prior studies of myelin-reactive CD8+ T cells in MS have relied on in vitro stimulation, thereby limiting accurate measurement of their ex vivo precursor frequencies and phenotypes. Peptide:MHC I tetramers were used to identify and validate 5 myelin CD8+ T cell epitopes, including 2 newly described determinants in humans. The validated tetramers were used to measure the ex vivo precursor frequencies and phenotypes of myelin-specific CD8+ T cells in the peripheral blood of untreated MS patients and HLA allele-matched healthy controls. In parallel, CD8+ T cell responses against immunodominant influenza epitopes were also measured. There were no differences in ex vivo frequencies of tetramer-positive myelin-specific CD8+ T cells between MS patients and control subjects. An increased proportion of myelin-specific CD8+ T cells in MS patients exhibited a memory phenotype and expressed CD20 compared to control subjects, while there were no phenotypic differences observed among influenza-specific CD8+ T cells. Longitudinal assessments were also measured in a subset of MS patients subsequently treated with anti-CD20 monoclonal antibody therapy. The proportion of memory and CD20+ CD8+ T cells specific for certain myelin but not influenza epitopes was significantly reduced following anti-CD20 treatment. This study, representing a characterization of unmanipulated myelin-reactive CD8+ T cells in MS, indicates these cells may be attractive targets in MS therapy

Critical Realism and Statistical Methods: A Response to Nash

This article offers a defence of critical realism in the face of objections Nash (2005) makes to it in a recent edition of this journal. It is argued that critical and scientific realisms are closely related and that both are opposed to statistical positivism. However, the suggestion is made that scientific realism retains (from statistical positivism) a number of elements that result in misleading accounts of social processes and events: indicators are used which do not reflect the close relationship between structure and agency; indicators refer to reified and not real properties of both structures and agents; and indicators do not refer to causal properties of objects and entities. In order to develop a narrative of causal processes, as Nash argues researchers should, then some adjustments need to be made to the principles that underpin scientific realism