482 research outputs found

    Winter wheat, winter rape and poppy crop growth evaluation with the help of remote and proximal sensing measurements

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    Monitoring of agricultural crops with the help of remote and proximal sensors during the growing season plays important role for site-specific management decisions. Winter wheat, winter rape and poppy are representatives of typical agricultural crops from the family Poacea, Brassicaceae and Papaveraceae, growing in relative dry area of Rakovník district in the Czech Republic. Ten Sentinel 2 satellite images acquired during vegetation season of the crops were downloaded and processed. Crops were monitored with the help of unmanned aerial vehicles (UAV) equipped with consumer grade Red Green Blue (RGB) camera and multispectral (MS) MicaSense RedEdge MX camera. In-field variability was assessed by computing RGB-based vegetation indices Triangular Greenness Index (TGI), Green Leaf Index (GLI) and Visible Atmospherically Resistant Index (VARI) and commonly used vegetation indices as Normalised Difference Vegetation Index (NDVI) and Green NDVI (GNDVI). The results derived from satellite and UAV images were supported with in-situ measurements of hand-held GreenSeeker and Chlorophyll Meter Content sensors. The study showed the usability of individual vegetation indices, especially the TGI index for chlorophyll content estimation, and VARI index for green vegetation fraction detection and leaf area index estimation, in comparison with selected handheld devices. The results showed as well that leaf properties and canopy structure of typical characteristics of selected families can significantly influence the spectral response of the crops detected in different phenological stages

    Assessment of soil electrical conductivity using remotely sensed thermal data

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    ArticleDetection of heterogeneity (crop, soil, etc.) gained a lot of importance in the field of site - specific farming in recent years and became possible to be measured by different sensors. The therma l spectrum of electromagnetic radiation has a great potential today and experiments focused on describing a relation between canopy temperature and various vegetation characteristics are conducted. This paper was aimed to examine the relation between canop y temperature and electrical conductivity as one of staple soil characteristics. The related experiment was undertaken in Sojovice, Czech Republic, within an agricultural plot where winter wheat was grown in 2017 growing season. The examined plot was compo sed of three sub plots and 35 control points were selected within this area which the data were related to. A canopy was sensed by UAV (eBee carrying thermoMAP (FLIR TAU2) camera). Soil conductivity data were collected by terrestrial sampling using EM38 - MK 2 Ground Conductivity Meter in 1 m depth and 2 m sampling point distance. This dataset was later interpolated using the kriging method. The correlation analysis results showed a strong negative correlation between conductivity and thermal data ( - 0.82; p < 0.001 ). When comparing conductivity with NDVI representing the aboveground biomass, there was an opposite trend but also strong result (0.86; p < 0.001 ). Correlation coefficient of thermal data and NDVI comparison was - 0.86; ( p < 0.001 ). These preliminary results have a potential for further research in terms of soil characteristics studies

    A reactive neural network framework for water-loaded acidic zeolites

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    Under operating conditions, the dynamics of water and ions confined within protonic aluminosilicate zeolite (H-AS) micropores are responsible for many of their properties, including hydrothermal stability, acidity and catalytic activity. However, due to high computational cost, operando studies of H-AS are currently rare and limited to specific cases and simplified models. In this work, we have developed a general potential energy surface interpolator with consistent accuracy for the entire class of H-AS, including the full range of experimentally relevant water concentrations and Si/Al ratios, via a reactive neural network potential (NNP). This NNP combines dramatic sampling acceleration at the metaGGA reference level with the capacity for discovery of new chemistry, such as collective defect formation mechanisms at the zeolite surface. Furthermore, we show that the baseline model allows for data-efficient adoption of higher-level (hybrid) references via Δ\Delta-learning and the acceleration of rare event sampling via automatic construction of collective variables. This framework allows for operando simulations of realistic catalysts at quantitative accuracy.Comment: Supplementary information adde

    At the Gates: The Tantalum-Rich Phase Hf3Ta2O11 and its Commensurately Modulated Structure

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    Generic mixtures in the system (Zr,Hf)O2–(Nb,Ta)2O5 are employed as tunable gate materials for field-effect transistors. Whereas production processes and target compositions are well-defined, resulting crystal structures are vastly unexplored. In this study, we summarize the sparse reported findings and present the new phase Hf3Ta2O11 as synthesized via a sol–gel route. Its commensurately modulated structure represents the hitherto unknown, metal(V)-richest member of the family (Zr,Hf)x(Nb,Ta)2O2x+5. Based on electron, neutron, and X-ray diffraction, the crystal structure is described within modern superspace [Hf1.2Ta0.8O4.4, Z = 2, a = 4.7834(13), b = 5.1782(17), c = 5.064(3) Å, q = 1/5c*, orthorhombic, superspace group Xmcm(00γ)s00] and supercell formalisms [Hf3Ta2O11, Z = 4, a = 4.7834(13), b = 5.1782(17), c = 25.320(13) Å, orthorhombic, space group Pbnm]. Transmission electron microscopy shows the microscopic structure from film-like aggregates down to atomic resolution. Cation ordering within the different available coordination environments is possible, but no significant hint at it is found within the limits of standard diffraction techniques. Hf3Ta2O11 is an unpredicted compound in the above-mentioned oxide systems, in which stability ranges have been disputably fuzzy and established only by syntheses via solid-state routes so far.DFG, SPP 1613, Regenerativ erzeugte Brennstoffe durch lichtgetriebene Wasserspaltung: Aufklärung der Elementarprozesse und Umsetzungsperspektiven auf technologische Konzept

    Production of Poly(vinylalcohol) Nanoyarns Using a Special Saw-like Collector

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    This work introduces an electrospinning method for laboratory-scale production of nanofibrous materials from polyvinylalcohol (PVA) nanofibres. A procedure for the subsequent production of twisted yarns from the aligned nanofibrous strand is introduced as well. Both needle and needleless electrospinning variants were employed Mechanical properties of the nanoyarns produced were tested using a VIBRODYN 400 and their morphology was investigated by light and electron microscopy. The work also introduces a simple analysis of the field strength that causes the prevailing unidirectional fiber deposition between neighbouring lamellae of a special saw-like collector The field strength analysis was carried out both analytically and by modelling based on the software COMSOL Multiphysics.MSMT project CARSILA [ME10145]; [GACR: P208/12/0105

    N-Glycan profiling of lung adenocarcinoma in patients at different stages of disease

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    Lung adenocarcinoma (LAC) is the most common form of lung cancer that increases in non-smokers at younger age. Altered protein glycosylation is one of the hallmarks of malignancy, its role in cancer progression is still poorly understood. In this study, we report mass spectrometric (MS) analysis of N-glycans released from fresh or defrosted tissue specimens from 24 patients with LAC. Comparison of cancerous versus adjacent healthy tissues revealed substantial differences in N-glycan profiles associated with disease. The significant increase in paucimannose and high-mannose glycans with 6-9 mannose residues and decline in the sialylated complex biantenary core fucosylated glycan with composition NeuAcGal(2)GlcNAc(2)Man(3)GlcNAc(2)Fuc were general features of tumors. In addition, 42 new N-glycan compositions were detected in cancerous tissues. The prominent changes in advanced disease stages were mostly observed in core fucosylated N-glycans with additional fucose (Fuc) residue/s and enhanced branching with non-galactosylated N-acetyl-glucosamine (GlcNAc) units. Both of these monosaccharide types were linked preferably on the 6-antenna. Importantly, as compared with noncancerous tissues, a number of these significant changes were clearly detectable early on in stage I. Application of N-glycan data obtained from tissues was next assessed and validated for evaluation of small sized biopsies obtained via bronchoscopy. In summary, observed alterations and data of newly detected N-glycans expand knowledge about the glycosylation in LAC and may contribute to research in more tailored therapies. Moreover, the results demonstrate effectiveness of the presented approach for utility in rapid discrimination of cancerous from healthy lung tissues
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