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  • Author or Editor: Á. Kovács x
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An incubation experiment was set up to investigate the effects of NPK fertilizers, wheat straw and food waste compost in combination with Phylazonit MC biofertilizer on the changes in 0.01 M CaCl 2 extractable nitrogen forms (NO 3 + -N, NH 4 + -N, organic-N fraction) of three types of soils. The quantities and changes in CaCl 2 -NH 4 + -N mainly depended on the adsorption capacity of soils. Higher CaCl 2 extractable NH 4 + -N values were measured in the calcareous chernozem and sandy soil with the application of NPK treatment, while in case of the chernozem soil with loamy texture no significant differences were found between the NPK and control treatments. NH 4 + immobilization appeared in pots given straw treatment. The quantity of CaCl 2 -NH 4 + -N changed within the incubation period, the direction and extent of the change were dependent of the production rates and consumption processes. In all soils the 0.01 M CaCl 2 extractable NO 3 - -N was the largest pool for plant nutrition. The highest CaCl 2 -NO 3 - -N values were found in pots given NPK and combined NPK+straw treatments, while the lowest values were measured in straw-treated pots. Wheat straw, with higher C/N ratio caused a temporary immobilization, followed by remineralization. Food waste compost, with lower C/N ratio, proved to have a good N supplying capacity. The contrasted effect of straw and compost was more conspicuous in sandy soil, in which the original NO 3 - -N content was the lowest. Higher CaCl 2 -organic N values were measured for pots treated with straw and with compost, as compared to the control. During the incubation period the amount of soluble organic-N changed, the direction and extent of the change depended on the soil type and treatments. The effect of Phylazonit MC was on the quantity of CaCl 2 extractable N fractions was not really expressed, and the significancy of the effect varied and was dependent of the soil type. Biofertilizer amendment increased the extractable NO 3 - -N in sandy soil, decreased the negative effect of wheat straw, and it also might help in decomposing wheat straw and food waste compost. The application of Phylazonit MC in the calcareous chernozem caused a significantly higher amount of organic-N, especially in straw-treated pots.

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Abstract  

Volatilization and thermochromatographic separation of ultramicro amounts of Mo and Tc from AgCl melt irradiated with 6 60 MeV protons have been studied in vacuum at 600 °C. It has been found that in quartz apparatus Tc, and while using graphite, Mo can be separated from the other leaving elements. On the basis of the experimental results an ion source can be contructed for the on-line nuclear spectroscopic studies of Mo and Tc isotopes.

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Abstract  

We investigate various number system constructions. After summarizing earlier results we prove that for a given lattice Λ and expansive matrix M: Λ → Λ if ρ(M −1) < 1/2 then there always exists a suitable digit set D for which (Λ, M, D) is a number system. Here ρ means the spectral radius of M −1. We shall prove further that if the polynomial f(x) = c 0 + c 1 x + ··· + c k x k Z[x], c k = 1 satisfies the condition |c 0| > 2 Σ i=1 k |c i | then there is a suitable digit set D for which (Z k , M, D) is a number system, where M is the companion matrix of f(x).

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Cryopreservation appears to be a suitable solution for the maintenance of potato germplasms. The protocol described in this paper can be applied for the vitrification and preservation of meristems. During histo-cytological studies it is possible to observe modifications at the cellular level and to understand the adaptive mechanism to low temperatures. Control potato meristem tissue contained a number of meristematic cells with a gradient of differentiation. After freezing there were a large number of vacuolated cells, some of which exhibited broken cell walls and plasmolysis. The thickening of the cell wall, giving them a sinuous appearance, was observed after freezing and thawing the meristems, with ruptures of the cuticle and epidermal layer.

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Modern agriculture is one of the main anthropogenic threats to biodiversity. To explore the effects of agricultural intensification we investigated carabids and spiders in two studies; in 2003 in grasslands and two years later in cereal fields in the same region. Both aimed to study the effect of management on arthropod diversity and composition at local and landscape scales. In 2003, we used a paired design for grasslands (extensively vs. intensively grazed). In 2005, a gradient design was applied with a total of seven land-use intensity categories. In both studies, sampling was carried out using funnel traps with the same sampling effort. Linear mixed models showed that high grazing intensity in grasslands had a positive effect on carabid species richness and abundance, but no effect on spiders. Landscape diversity had a positive effect only on carabid abundance. In the case of cereal fields, the management intensity (nitrogen fertiliser kg/ha) had a negative effect on spider richness and no effect on carabids. After variance partitioning, both local and landscape characteristics seem to be important for both cereal and grassland arthropod communities. Based on our results, we think that current and future agri-environmental schemes should be concentrated on cropland extensification. Low intensity croplands could act as a buffer zone around the semi-natural grasslands, at least in this biogeographic region.

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The potentiometric electronic tongue is a new and rapidly developing technique. However, the description of the exact working mechanism is still absent. An important part of this description is the effect of the sample temperature on the measurement results. The paper reported here gives a description of the effect of temperature on results obtained with an α-Astree potentiometric electronic tongue. The yielded model was used to perform a temperature correction as if the samples were measured at room temperature (25 °c).

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Liver cells of the twenty-one day old rat embryo are isolated by a modified method and autophagy is studied in them by electron microscopic morphology and morphometry. Immediately after isolation or 2.5 h incubation in nutrient-free medium, embryonic hepatocytes contain high amount of glycogen and only very few autophagic vacuoles. In contrast, all glycogen is lost and 15% of the cytoplasmic volume is occupied by late autophagic vacuoles in hepatocytes after 18 h in the same medium. Presence of 3- methyladenine in the latter case inhibits both the loss of glycogen and the appearance of autophagic vac- uoles while enlarging the multivesicular body compartment. Our findings reveal major differences between isolated embryonic and adult hepatocytes concerning autophagy. Several types of autophagic vacuoles are described in the cell types of the erythropoietic cell lineage. This means that autophagy is an integral part of erythropoiesis not only in bone marrow, but also in embryonic liver that is investigat- ed here for the first time from this point of view. The presence of unclosed isolation membranes and the predominance of early autophagic vacuoles in reticulocytes indicates that the molecular machinery of segregation is still active in this functionally and structurally highly reduced cell type.

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Seven traits of twelve hybrids derived from direct and reciprocal crosses of four parental lines were examined during three years in Hungary. No significant differences were found between the direct and reciprocal crosses for stalk diameter or leaf number over the average of three years in any of the hybrids. Significant differences in the number of primary tassel branches were observed between UDH5 and its reciprocal UDH8, and between UDH6 and its reciprocal UDH11. It was evident in both instances that the degree of heterosis in the reciprocal crosses far exceeded that in the direct ones. A high number of tassel branches was dominant over a low number, so this trait was preferentially inherited in the hybrids. A positive correlation was observed between plant height and main ear attachment height (r = 0.67**). A positive correlation (r = 0.89**) was also found between the length of the main tassel axis above the lowest and above the uppermost side-branch. A medium correlation was observed between the number of primary tassel branches and the plant height (r = −0.42**). The number of primary tassel branches exhibited the highest heterosis. These results can be utilized in practical selection and seed production.

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