Meeting the Tolerance: How Successful is Coexistence in Commodity Corn Handling Systems?

2020 ◽  
Vol 36 (5) ◽  
pp. 777-784
Author(s):  
Chad J. Dolphin ◽  
Gretchen A. Mosher ◽  
R.P. Kingsly Ambrose ◽  
Saxon J. Ryan
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Genetically Modified ◽  
List Type ◽  
Genetic Traits ◽  
Tolerance Level ◽  
Gm Maize ◽  
Isolation Distance ◽  
Adventitious Presence ◽  
Handling Practices

HighlightsMeeting the 0.9% tolerance level was challenging under most conditions.Non-GM loads in the simulation were able to meet a 1.5% or 3% tolerance level under specific conditions.Field isolation distance plays a large role in a non-GM load meeting the posted tolerance levelAbstract. The open-air growth environment used in maize production makes it nearly impossible to ensure 100% purity of specified genetic traits. One measure of successful coexistence is a low level of unintended material in seed, grain, and feed or food products, termed “adventitious presence” (AP). To allow the coexistence of genetically modified (GM) and non-genetically modified (non-GM) maize, tolerance levels regulate how much AP of genetically modified corn is allowed in each unit of maize. This research sought to model four factors contributing to levels of adventitious presence: seed purity, field isolation distance, combine cleanout, and grain elevator receipt and handling practices. Monte Carlo simulation was used to test nine scenarios to determine the feasibility of successfully meeting three tolerance levels for adventitious presence (0.9%, 1.5%, and 3.0%). After 50,000 iterations for each model, sensitivity analysis was performed to identify factors that play an important role in whether the load meets the posted tolerance level or not. Results suggest that non-GM maize loads would not meet a tolerance level of 0.9% in most cases. Non-GM maize loads were found to meet tolerance levels of 1.5% and 3.0% in certain cases. The most significant factors affecting the probability of the unit of maize meeting the posted tolerance level were field isolation distance, elevator handling practices, and seed purity. Keywords: Adventitious presence, Coexistence, Identity preservation, Monte Carlo simulation, Transgenic grain.

scholarly journals Developing a Graphical User Interface (GUI) to Predict the Contamination of GM Corn in Non-GM Corn

2020 ◽  
Vol 36 (1) ◽  
pp. 25-31
Author(s):  
Karthik Salish ◽  
Gretchen A Mosher ◽  
R. P. Kingsly Ambrose
Keyword(s):  
User Interface ◽  
Probability Distribution ◽  
Graphical User Interface ◽  
Genetic Modification ◽  
Genetically Modified ◽  
Threshold Level ◽  
Percentage Error ◽  
List Type ◽  
Tolerance Level ◽  
Adventitious Presence

HighlightsA GUI tool was developed to predict the adventitious presence in non-GM produce.The software calculates tolerance and the probability of GM corn in non-GM corn.Predicted probability of contamination ranged from 0.050 to 0.356 at tolerance levels ranging from 0.1% to 5.0%.Abstract. The current rate of population growth necessitates the use of viable technologies like genetic modification to address estimated global food and feed requirements. However, in recent years, there has been an increase in resistance against the diffusion of genetic modification technology around the world. Many countries have adopted coexistence policies to allow a certain percentage of adventitious presence in non-genetically modified crops. However, the tolerance percentage for adventitious presence has been a bottleneck to free trade in some cases. It is a challenging task to fix a tolerance percentage considering the level of permeation of genetic modification technology in agriculture. This article introduces a software developed to serve as a decision-making tool to predict the probability distribution of genetically modified (GM) contamination in non-GM grain lot using user inputs such as final quantity of processed corn, overall tolerance level, and moisture content. The output from the software includes the mass of corn in each processing stage, the tolerance level and the probability distribution of potential GM contamination. The software predicted the probability of contamination with adventitious presence at tolerance levels of 5.0%, 3.0%, 1.0%, 0.9%, 0.5%, and 0.1% as 0.05, 0.07, 0.11, 0.12, 0.16, and 0.36, respectively. The predictions from the model were compared to a similar study wherein the effect of tolerance levels incurred in the costs of segregation was studied. The mean absolute percentage error for the predictions was found to be 3.07%. This software can be used as a tool in testing GM contamination in non-GM grain against a desired threshold levels in a grain elevator. Keywords: Corn, Genetic modification, Graphical User Interface (GUI), Threshold level.

Applications of Monte Carlo Simulation of Electron Scattering to Quantitative X-Ray Microanalyses

2001 ◽  
Vol 7 (S2) ◽  
pp. 690-691
Author(s):  
Kenji Murata ◽  
Masaaki Yasuda ◽  
Syunji Yamauchi
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Elastic Scattering ◽  
Energy Loss ◽  
Cross Section ◽  
Electron Scattering ◽  
List Type ◽  
Discrete Energy ◽  
X Ray ◽  
Loss Process

Monte Carlo simulation of electron scattering has been widely used in various fields such as microanalysis, microscopy and microlithography. Various simulation models have been reported so far. in applications to quantitative x-ray microanalysis the accuracy of the model has been significantly improved by introducing the Mott cross section. However, in the analyses at low energies of an electron beam or at energies near the x-ray excitation energy, the simulation accuracy becomes worse. This is probably because the discrete energy loss process is not incorporated into the simulation model. to improve this default, we developed the model which includes the discrete energy loss process[l]. The outline of the model is described in the following.1)Elastic scatteringWe used the Mott cross section. The Mott cross sections for Al, Cu, Ag and Au elements are calculated at various energies. From this data base we obtain the differential elastic scattering cross section and the total elastic cross section for arbitarary elements and energies by using the interporation or the extrapolation.

scholarly journals Effect of MON 810 cultivation and prevention to adventitious presence in non-GM fields: A case study in Slovakia

2012 ◽  
Vol 48 (Special Issue) ◽  
pp. S11-S15 ◽  
Author(s):  
P. Mihalčík ◽  
K. Hrčková ◽  
M. Singer ◽  
A. Plačková ◽  
J. Kraic
Keyword(s):  
European Corn Borer ◽  
Climatic Conditions ◽  
Corn Borer ◽  
Gm Maize ◽  
Growing Seasons ◽  
Isolation Distance ◽  
Adventitious Presence ◽  
Self Protection ◽  
Mon 810

The efficiency of border rows to prevent the adventitious presence of GM maize in non-GM maize plots was evaluated as well as the effect of the MON 810 maize of the yield and self-protection against the European corn borer. The GM maize MON 810 event was drilled at 3 locations over the Slovakia and the grain samples were collected from the neighbouring conventional maize fields. The data obtained by Real-Time PCR indicate that coexistence between GM and conventional maize is feasible and the isolation distance of 200 m (respectively 100 border rows of conventional maize) separates GM maize from the conventional one more than sufficiently. The effective isolation distance is 3–4 times greater than the actually needed. The MON 810 revealed also the highest yield and the best self-protection against European corn borer in both growing seasons with different climatic conditions. 

Electron Scattering in Solids

1990 ◽  
Vol 48 (2) ◽  
pp. 4-5
Author(s):  
Ryuichi Shimizu ◽  
Ze-Jun Ding
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Angular Distribution ◽  
Elastic Scattering ◽  
Electron Scattering ◽  
Cross Sections ◽  
Expansion Method ◽  
Electron Excitation ◽  
Partial Wave Expansion ◽  
Backscattered Electrons

Monte Carlo simulation has been becoming most powerful tool to describe the electron scattering in solids, leading to more comprehensive understanding of the complicated mechanism of generation of various types of signals for microbeam analysis.The present paper proposes a practical model for the Monte Carlo simulation of scattering processes of a penetrating electron and the generation of the slow secondaries in solids. The model is based on the combined use of Gryzinski’s inner-shell electron excitation function and the dielectric function for taking into account the valence electron contribution in inelastic scattering processes, while the cross-sections derived by partial wave expansion method are used for describing elastic scattering processes. An improvement of the use of this elastic scattering cross-section can be seen in the success to describe the anisotropy of angular distribution of elastically backscattered electrons from Au in low energy region, shown in Fig.l. Fig.l(a) shows the elastic cross-sections of 600 eV electron for single Au-atom, clearly indicating that the angular distribution is no more smooth as expected from Rutherford scattering formula, but has the socalled lobes appearing at the large scattering angle.

Determination of Stoichiometry of GaAs Component in (Gaas)Ge Epitaxially Grown Thin Films by Electron Microprobe X-Ray Analysis

1990 ◽  
Vol 48 (2) ◽  
pp. 264-265
Author(s):  
D. R. Liu ◽  
S. S. Shinozaki ◽  
R. J. Baird
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Compound Semiconductors ◽  
Energy Dispersive Analysis ◽  
X Ray ◽  
Metastable Alloys ◽  
Lower Voltage

The epitaxially grown (GaAs)Ge thin film has been arousing much interest because it is one of metastable alloys of III-V compound semiconductors with germanium and a possible candidate in optoelectronic applications. It is important to be able to accurately determine the composition of the film, particularly whether or not the GaAs component is in stoichiometry, but x-ray energy dispersive analysis (EDS) cannot meet this need. The thickness of the film is usually about 0.5-1.5 μm. If Kα peaks are used for quantification, the accelerating voltage must be more than 10 kV in order for these peaks to be excited. Under this voltage, the generation depth of x-ray photons approaches 1 μm, as evidenced by a Monte Carlo simulation and actual x-ray intensity measurement as discussed below. If a lower voltage is used to reduce the generation depth, their L peaks have to be used. But these L peaks actually are merged as one big hump simply because the atomic numbers of these three elements are relatively small and close together, and the EDS energy resolution is limited.

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