Mathematical Modeling of Agricultural Crop Diversification in Ukraine: Scientific Approaches and Empirical Results*

The paper describes an agricultural crop diversification model on the basis of simulation modeling and robust solutions. The model is intended for the design and development of the optimal structure of crop areas in order to combine the agricultural crops in a compatible manner, and to gradually transition to the principles of sustainable farming in domestic agriculture. A detailed analysis of the modern practice of monoculture farming was conducted. Based on these calculations, a diversified structure of ten agricultural crops is proposed, which will help strengthen the internal food security and harmonize agricultural development in its ecological, social, and economic aspects

A Risk-Informed Decision-Making Framework for Climate Change Adaptation through Robust Land Use and Irrigation Planning

Uncertainty and variability are key challenges for climate change adaptation planning. In the face of uncertainty, decision-making can be addressed in two interdependent stages: make only partial ex ante anticipative actions to keep options open until new information is revealed, and adapt the first-stage decisions with respect to newly acquired information. This decision-making approach corresponds to the two-stage stochastic optimization (STO) incorporating both anticipative ex ante and adaptive ex post decisions within a single model. This paper develops a two-stage STO model for climate change adaptation through robust land use and irrigation planning under conditions of uncertain water supply. The model identifies the differences between decision-making in the cases of perfect information, full uncertainty, and two-stage STO from the perspective of learning about uncertainty. Two-stage anticipative and adaptive decision-making with safety constraints provides risk-informed decisions characterized by quantile-based Value-at-Risk and Conditional Value-at-Risk risk measures. The ratio between the ex ante and ex post costs and the shape of uncertainty determine the balance between the anticipative and adaptive decisions. Selected numerical results illustrate that the alteration of the ex ante agricultural production costs can affect crop production, management technologies, and natural resource utilization

Neutrophil Activation by Mineral Microparticles Coated with Methylglyoxal-Glycated Albumin

Hyperglycemia-induced protein glycation and formation of advanced glycation end-products (AGEs) plays an important role in the pathogenesis of diabetic complications and pathological biomineralization. Receptors for AGEs (RAGEs) mediate the generation of reactive oxygen species (ROS) via activation of NADPH-oxidase. It is conceivable that binding of glycated proteins with biomineral particles composed mainly of calcium carbonate and/or phosphate enhances their neutrophil-activating capacity and hence their proinflammatory properties. Our research managed to confirm this hypothesis. Human serum albumin (HSA) was glycated with methylglyoxal (MG), and HSA-MG was adsorbed onto mineral microparticles composed of calcium carbonate nanocrystals (vaterite polymorph, CC) or hydroxyapatite nanowires (CP). As scopoletin fluorescence has shown, H2O2 generation by neutrophils stimulated with HSA-MG was inhibited with diphenyleneiodonium chloride, wortmannin, genistein and EDTA, indicating a key role for NADPH-oxidase, protein tyrosine kinase, phosphatidylinositol 3-kinase and divalent ions (presumably Ca2+) in HSA-MG-induced neutrophil respiratory burst. Superoxide anion generation assessed by lucigenin-enhanced chemiluminescence (Luc-CL) was significantly enhanced by free HSA-MG and by both CC-HSA-MG and CP-HSA-MG microparticles. Comparing the concentrations of CC-bound and free HSA-MG, one could see that adsorption enhanced the neutrophil-activating capacity of HSA-MG

The effect of Gd doping on carrier concentration in InGaAsSb layers grown by liquid phase epitaxy

It is shown that addition of Gd to the melt during liquid phase epitaxy growth of InGaAsSb layers greatly reduces contamination of the samples with residual donor impurities, such as sulfur and silicon. The effect is related to Gd gettering of these impurities in the melt. © 1994

Hydrogen passivation effects in quaternary solid solutions of InGaAsSb lattice matched to GaSb

Hydrogen passivation effects in InAs-related and GaSb-related InGaAsSb layers lattice matched to GaSb have been studied. Strong passivation of shallow acceptors has been observed and is explained by the assumption that hydrogen is a deep donor in these materials. The effects of the hydrogen treatment mode on the passivation efficiency are also discussed, as well as the changes induced by hydrogen treatment in photoluminescence spectra of the layers. © 1994

Hydrogen passivation effects in InGaAlP and InGaP

The effects of hydrogen treatment on electrical properties, luminescence spectra, and deep traps in InGaAlP and InGaP have been studied. It is shown that acceptors and donors (both shallow and deep) can be effectively passivated by hydrogen. The hydrogen is found not only to passivate the main electron and hole traps in our samples, but also to generate electron traps in n-InGaAlP and hole traps in p-InGaP. The influence of hydrogen treatment mode (direct plasma or a crossed-beams source in which the low-energy ion bombardment of the surface is effectively eliminated) on hydrogen concentration and hydrogen profiles in InGaAlP are discussed. © 1994 American Institute of Physics

Hydrogen passivation effects in InGaAlP and InGaP

The effects of hydrogen treatment on electrical properties, luminescence spectra, and deep traps in InGaAlP and InGaP have been studied. It is shown that acceptors and donors (both shallow and deep) can be effectively passivated by hydrogen. The hydrogen is found not only to passivate the main electron and hole traps in our samples, but also to generate electron traps in n-InGaAlP and hole traps in p-InGaP. The influence of hydrogen treatment mode (direct plasma or a crossed-beams source in which the low-energy ion bombardment of the surface is effectively eliminated) on hydrogen concentration and hydrogen profiles in InGaAlP are discussed. © 1994 American Institute of Physics