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  • Author or Editor: Z. Wittmann x
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large-pot model experiments were conducted with maize under greenhouse conditions with the aim of studying the effect of different N fertiliser forms, water supplies and crop residues on the nitrogenous gas production in the rooting zone. Nitrogen fertiliser was applied in the form of KNO3 or NH4Cl. The experiment was done at two soil moisture levels, with or without the incorporation of maize crop residues into the soil, and with or without test plants. Gas traps were placed in the pots at a soil depth of 20 cm. During the growing season, the trapped soil air was analysed for NOx, N2O and N2. Practically the same N amounts evolved in the soil air with both chemical forms of N fertiliser at both soil moisture levels. expressed as a percentage of fertiliser N, the total amount of gaseous N evolved averaged 12.8% and 12.9% in the planted, and 23.8% and 24.3% in the unplanted pots with KNO3 and NH4Cl fertiliser, respectively. Higher soil moisture and the incorporation of crop residues resulted in higher NOx-N and N2O-N ratios within the total gaseous N evolved in the rooting zone.

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Acta Physiologica Hungarica
Authors: Éva Zöllei, Dóra Paprika, T Wittmann, A Rosztóczy, R Róka, Z Gingl and L Rudas

We compared the cardiovascular responses in 10 patients with established gastro-oesophageal reflux disease (Group 1) and 10 control subjects (Group 2) during oesophageal saline and 0.1 mol/l hydrochloric acid instillation. Indices of heart rate and blood pressure variability and baroreflex gain (derived from linear spontaneous sequences and cross spectral analysis) were calculated. In Group 1 the standard deviation of RR intervals (SDRR: 46 ms vs. 51 ms, p=0.030) and the root mean square of successive differences (RMSSD: 24 ms vs. 26 ms, p=0.027) were significantly lower during acid infusions, than during saline. We found no significant difference in minimum, maximum and mean RR intervals and systolic blood pressures and in the percentage of RR intervals, which differed from adjacent cycles by more than 50 ms (PNN50). The power spectra of RR intervals in the high frequency band tended to be lower during acid infusion (p=0.055). There was no significant difference in blood pressure spectra, neither in low nor in high frequency band. In Group 2 there was no significant difference between any parameters measured during acid and saline. The baroreflex gain was not changed during the studied conditions in any group.

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