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The agricultural production in mathematical models

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The theoretical questions of mathematical modeling of agricultural production processes are described. Production of agricultural goods and foodstuffs is modeled except for the production of forage and involvement of equipment and techniques, buildings, infrastructure etc. The model is based on a division of economic and technological processes in agriculture into four stages specific for agribusiness. A mathematical description of four stages in used production functions is provided.
The study has determined the composition of dissolved organic matter in Luvisols, Fluvisols and Histosols using spectroscopic (FTIR) and chromatographic (HPLC and Py-GCMS) methods. It has been found that aliphatic hydrocarbons (linear) containing from 4 to 12 atoms of carbon constitute the dominant group of compounds included in the dissolved organic matter (DOC). The preparations isolated from Histosols and Luvisols demonstrated a higher proportion of hydrophobic fraction with a longer retention time probably containing more compounds with long-chain aliphatic and simple aromatic structure than the DOC of Fluvisols. The differences in infrared spectra are evident particularly in the wave number between 1650–1030 cm⁻¹. The DOC of Histosols is richer in aromatic compounds (range 1620 cm⁻¹) but the DOC of Luvisols and Fluvisols is richer in alkene chains and hydroxyl (OH) and methoxy (OCH₃) groups. The results showed differences in the composition of the DOM across the soils, caused their genesis.
Estimation of the technical efficiency which measures the ability of a company to obtain the maximum output from given inputs or to use the minimum input to achieve given outputs has been considered. Stochastic methods were chosen because of their wide application in research in the whole world. The Translog and Cobb-Douglas stochastic frontiers were fitted in order to estimate the efficiency of milling companies in Poland.
The main aim of the study was to determine which of the viability and germination capacity of pollen grains estimation methods are optimal and to test if the studied sections and species within the Rosa genus are differentiated in pollen viability andgermination capacity. We analysedandcomparedpollen grains of 14 wild Rosa species using 5 viability tests and13 various liquidandagar media. Viability of pollen grains in the majority of the examinedspecies was greater than their germination capacity. The most viable pollen grains were foundin R. gallica (section Gallicanae), where average of 5 viability tests is 90.69%, andin R. pendulina (section Rosa) – 86.85%. Species from section Caninae have a lower level of viability (from 60.59% in R. rubiginosa to 31.23% in R. inodora). Pollen of species from sections Gallicanae (R. gallica; to 63.4%) and Rosa (R. pendulina; to 47.21%) germinatedmuch better than the pollen of the majority of species from section Caninae (with the exception of R. zalana; to 47.22%). The examinedpollen grains germinatedmost numerously on agar medium with 1.5% agar+15% sucrose+50 ppm boric acidandliquidmed ium with 15% sucrose+ 50 ppm boric acid. Following deep-freeze storage (–25°C) for six months, the pollen grains of nine selected species (with the exception of R. rubiginosa) showed viability higher or similar to that before storage.
This study investigated the solid waste characterization of the city of Kocaeli. With this aim solid waste groups were analyzed for sub-municipalities of the city. Representative sampling points were determined in municipalities with populations over 5,000. Four different socio-economic groups (the downtown district plus low, intermediate, and high income levels) were investigated in the study. Characterization studies were performed for a 2-year period. In this context, 16 and 13 different solid waste species were categorized for winter and summer seasons, respectively. The results of the study showed that kitchen wastes constitute the highest proportion for all socio-economic groups despite dissimilarities in waste distribution of municipalities. It was followed by combustible wastes and plastic wastes. Reducing waste components into five groups as organic wastes, recycled wastes, hazardous wastes, combustible wastes and others, an increase was seen in amounts of recycled, hazardous, and combustible wastes in winter season, whereas the amount of organic wastes decreased. Investigating general waste distribution for different income levels without any seasonal distinction, it was observed that highest values of organic and recycled wastes were seen in the downtown district and high-income groups, whereas combustible, hazardous, and other wastes were higher in low-income groups. In general, as a result of the characterization study without any seasonal and/or economical distinctions, proportions of organic, recycled, combustible, hazardous wastes, and others were determined as 41.53%, 30.51%, 20.64%, 2.12%, and 5.20%, respectively.
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