This article is devoted to the comparison of the influence of the piezoelectric matrix properties on the magnitude of the resulting charge when a thin piezoelectric membrane of circular cross ...section, made from aluminium gallium nitride (Al-GaN), is loaded. The size of change of the electric charge was determined by the numerical analysis and the by the change of the properties of the piezoelectric matrix. The matrix constants were obtained from various sources introduced in world databases.
This article provides an overview and results of the pilot national ecosystem services assessment in Slovakia. It follows the MAES process and past ecosystem services (ES) research in Slovakia and is ...based on original research methodology using spatial and statistical data. The initial step of national ES assessment resulted in the selection of significant ES for the evaluation process, where 18 ES in three groups were selected (five provisioning, 10 regulatory/maintenance and three cultural ES). An original assessment model provided the theoretical and methodological framework for national ES evaluation. The principal result is an assessment of the national landscape’s capacity for ES provision, based on evaluation of the landscape units and selected properties and indicators at the ecosystem level. These inputs included habitat types and watersheds, administrative units, natural topology, geology, soils, climate, water and biota. The ES capacity models were created and evaluated for each ES, for the main groups and, finally, for overall ES provision. The highest capacity to provide ES in Slovakia comes from natural and semi-natural ecosystems, mainly deciduous, mixed and coniferous forests which cover over 38% of Slovak territory. The water ecosystems and wetlands are also significant, followed by grasslands and permanent crops. The research highlights the crucial importance of the mountainous and sub-mountainous areas in Slovakia and confirms the significant contribution of the natural and semi-natural ecosystems for ensuring ES provision.
Multi-analyte methods based on QuEChERS sample preparation and chromatography/mass spectrometry determination are indispensable in monitoring pesticide residues in the feed and food chain. QuEChERS ...method, even though perceived as convenient and generic, can contribute to sample matrix constituents’ introduction to the measuring system and possibly affect analytical results. In this study, matrix effects (ME) were investigated in four food matrices of plant origin (apples, grapes, spelt kernels, and sunflower seeds) during GC-MS/MS analysis of >200 pesticide residues using QuEChERS sample preparation. Data analysis revealed considerable analyte signal enhancement and suppression: strong enhancement was observed for the majority of analytes in two matrices within the commodity groups with high water content—apples, and high acid and water content—grapes (73.9% MES and 72.5% MEA, and 77.7% MES and 74.9% MEA, respectively), while strong suppression was observed for matrices within the commodity groups with high starch/protein content and low water and fat content—spelt kernels, and high oil content and very low water content—sunflower seeds (82.1% MES and 82.6% MEA, and 65.2% MES and 70.0% MEA, respectively). Although strong matrix effects were the most common for all investigated matrices, the use of matrix-matched calibration for each sample type enabled satisfactory method performance, i.e., recoveries for the majority of analytes (up to roughly 90%, depending on the fortification level and matrix type), which was also externally confirmed through participation in proficiency testing schemes for relevant food commodity groups with the achieved z-scores within acceptable range ≤ |2|.
Biflavonoids are flavonoid dimers that are much less studied than monomeric flavonoids. Their precise distribution among plants and their role in plants is still unknown. Here, we have developed a ...HPLC-DAD method that allows us to separate and simultaneously determine the five major biflavonoids (amentoflavone, bilobetin, ginkgetin, isoginkgetin, and sciadopitysin) in ginkgo (
L.). We performed tissue-specific profiling of biflavonoids in ten different plant parts: tree bark, twigs bark, twigs without bark, buds, leaf petioles, leaf blades, seed stalks, sarcotesta, nutshells, and kernels. We did not detect biflavonoids in plant parts not in direct contact with the environment (twigs without bark, nutshells, and kernels). We found the highest total biflavonoids content in leaves, where sciadopitysin was predominant. In contrast, in the bark, amentoflavone was the predominant biflavonoid, suggesting that more methylated biflavonoids accumulate in leaves and seeds. This is probably related to their biological function, which remains to be determined.
Microfiltration is a common step in liquid chromatography – tandem mass spectrometry (LC-MS), a method of choice in determining several mycotoxins in a solution at once. However, microfiltration may ...entail filter-analyte interactions that can affect the accuracy of the procedure, and underestimate exposure. The aim of our study was to assess how five different membrane materials for syringe filters (nylon, polytetrafluoroethylene, polyethersulphone, mixed cellulose ester, and cellulose acetate) affect microfiltration and recovery of EU-regulated mycotoxins, including aflatoxins B1, B2, G1, and G2, deoxynivalenol, fumonisins B1 and B2, zearalenone, T-2 and HT-2 toxins, and ochratoxin A. Polytetrafluoroethylene filters turned out to least affect microfiltration through mycotoxin loss, followed by more commonly used nylon filters, whereas the remaining three filter membrane materials had such a negative effect on recoveries that we found them incompatible with the procedure. Our findings clearly suggest that it is important to select a proper filter type that suits analyte properties and solution composition and to discard the first few filtrate drops to ensure the accuracy of the analytical procedure.
Aflatoxins (AF) are a group of toxic secondary metabolites mostly produced by strains of Aspergillus spp. fungi. There are several types of aflatoxins (AFB1, AFG1, AFB2, AFG2, AFM1, AFM2, etc.), but ...the most toxic and the most common is AFB1. Aflatoxins have been shown to possess powerful carcinogenic, mutagenic and teratogenic properties. AFB1 can contaminate feed and food during the growth and/or storage under inappropriate conditions. When animals consume AFB1-contaminated feed, it undergoes various metabolic pathways and finally, it is metabolized into hydroxylated metabolite AFM1, which is possibly excreted in milk if the animal is lactating. This issue presents a huge concern regarding the representation of milk and dairy products in the human diet. Furthermore, climate changes have a significant impact on aflatoxin production. Therefore, it is necessary to develop and improve strategies for controlling and mitigating the occurrence of AFM1 in milk and dairy products. The aim of this paper is to provide an overview of the latest scientific literature regarding the occurrence of AFM1 in milk and dairy products.
The importance of bicycle touring is currently getting more attention, mainly in other countries of the European Union, but recently also here in Slovakia. In the article, we focus on the impact of ...bicycle touring on tourism in Slovakia with its legislative provisions and on the design of new cycling routes. We pay special attention to the particular importance of bicycle touring in the town of Levice and the surrounding area. After analyzing and evaluating of the existing routes, we decide to propose two new ones, which could have a positive impact on the development of the territory. We designed the first route outside of the town of Levice (Levice-Dolná Seč-Vyšné nad Hronom-Žemliare-Jur nad Hronom-Starý Hrádok-Mýtne Ludany časť Dobogov - Levice) 29 km in length. We situated the second route in the built-up area of the town of Levice; its length is 6.9 km. Both proposed routes have “rekrea” difficulty, i.e., they are designed for families with children or cyclists with a lower fitness level.
Topic of this master's thesis is testing of selected items of financial statements from the auditor's perspective. Thesis is divided into 4 main chapters. The first three are methodological where the ...first of them describes characteristics of auditing as such, its meaning, functions, purpose and object. It also explains a role of the auditor, their job description, competence, responsibility and subsequently describes The Chamber of Auditors of the Czech Republic. The second chapter analyses legal regulations of the audit, ie. laws, regulations and standards that effect both the accounting and the audit. The third and final theoretical chapter describes the methodology and steps of the audit and all the activities that audit involves. The fourth, practical chapter includes explained methodology on selected financial statement items such as tangible and intangible fixed assets, personnel expenses, short-term financial assets, inventory, receivables, equity, reserve fund, revenues and expenses related to their own production and production margin.
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