104 research outputs found
Diversidad patogénica dentro de poblaciones de jopo de girasol (O. cumana)
Resúmes del XII Congreso Nacional de la Sociedad Española de FitopatologíaPeer reviewe
Сегментация изображения с помощью программного средства MatLab
In computer vision, image segmentation is the process of partitioning a digital image intomultiple segments (sets of pixels, also known as superpixels). The goal of segmentation is to simplify and/orchange the representation of an image into something that is more meaningful and easier to analyze. Imagesegmentation is typically used to locate objects and boundaries (lines, curves, etc.) in images. More precisely,image segmentation is the process of assigning a label to every pixel in an image such that pixels with thesame label share certain characteristics. The result of image segmentation is a set of segments that collectivelycover the entire image, or a set of contours extracted from the image
Gene expression profiling to characterize sediment toxicity – a pilot study using Caenorhabditis elegans whole genome microarrays
BACKGROUND: Traditionally, toxicity of river sediments is assessed using whole sediment tests with benthic organisms. The challenge, however, is the differentiation between multiple effects caused by complex contaminant mixtures and the unspecific toxicity endpoints such as survival, growth or reproduction. The use of gene expression profiling facilitates the identification of transcriptional changes at the molecular level that are specific to the bio-available fraction of pollutants. RESULTS: In this pilot study, we exposed the nematode Caenorhabditis elegans to three sediments of German rivers with varying (low, medium and high) levels of heavy metal and organic contamination. Beside chemical analysis, three standard bioassays were performed: reproduction of C. elegans, genotoxicity (Comet assay) and endocrine disruption (YES test). Gene expression was profiled using a whole genome DNA-microarray approach to identify overrepresented functional gene categories and derived cellular processes. Disaccharide and glycogen metabolism were found to be affected, whereas further functional pathways, such as oxidative phosphorylation, ribosome biogenesis, metabolism of xenobiotics, aging and several developmental processes were found to be differentially regulated only in response to the most contaminated sediment. CONCLUSION: This study demonstrates how ecotoxicogenomics can identify transcriptional responses in complex mixture scenarios to distinguish different samples of river sediments
Equilibrium sampling of polychlorinated biphenyls in River Elbe sediments – Linking bioaccumulation in fish to sediment contamination
AbstractEquilibrium sampling can be applied to measure freely dissolved concentrations (cfree) of hydrophobic organic chemicals (HOCs) that are considered effective concentrations for diffusive uptake and partitioning. It can also yield concentrations in lipids at thermodynamic equilibrium with the sediment (clip⇌sed) by multiplying concentrations in the equilibrium sampling polymer with lipid to polymer partition coefficients. We have applied silicone coated glass jars for equilibrium sampling of seven ‘indicator’ polychlorinated biphenyls (PCBs) in sediment samples from ten locations along the River Elbe to measure cfree of PCBs and their clip⇌sed. For three sites, we then related clip⇌sed to lipid-normalized PCB concentrations (cbio,lip) that were determined independently by the German Environmental Specimen Bank in common bream, a fish species living in close contact with the sediment: (1) In all cases, cbio,lip were below clip⇌sed, (2) there was proportionality between the two parameters with high R2 values (0.92–1.00) and (3) the slopes of the linear regressions were very similar between the three stations (0.297; 0.327; 0.390). These results confirm the close link between PCB bioaccumulation and the thermodynamic potential of sediment-associated HOCs for partitioning into lipids. This novel approach gives clearer and more consistent results compared to conventional approaches that are based on total concentrations in sediment and biota-sediment accumulation factors. We propose to apply equilibrium sampling for determining bioavailability and bioaccumulation potential of HOCs, since this technique can provide a thermodynamic basis for the risk assessment and management of contaminated sediments
Разработка расчетных методов определения характеристик индустриальных масел
В ходе работы проанализированы характеристики индустриального масла марки И-20А, с использованием метода множественного регрессионного анализа разработаны расчетные способы определения характеристик индустриального масла, сделан вывод о точности разработанных методов, определены наиболее точные методы.In the course of the work, the characteristics of I-20A industrial oil were analyzed, using the multiple regression analysis method, calculation methods for determining the characteristics of industrial oil were developed, a conclusion was made on the accuracy of the developed methods, and the most accurate methods were determined
Геохимические особенности антропогенных карбонатных отложений на территории Республики Башкортостан
Геохимические особенности антропогенных карбонатных отложений на территории Республики Башкортостан.Geochemical features of anthropogenic carbonate deposits on the territory of the Republic of Bashkortostan
Numerical simulation of heat transfer in a large room with a working gas infrared emitter
The article presents a new approach to determining the main characteristics of the thermal regime in the buildings and structures heated by the gas infrared emitters, based on the analysis of convective heat transfer in the air and thermal conductivity in the enclosing structures. The authors have considered a mathematical model of turbulent heat transfer in the framework of the standard k-e model under radiant heating conditions. The simulation was carried out for a large room with an approximation to the real operating conditions of an industrial facility. The options for heating an empty room and the room with an object were considered
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