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[en] Highlights: • Fertilization in organic and conventional systems increased N2O emissions. • Organic and conventional practice with 30 kg N ha−1 gave similar N2O emissions. • Cotton-legume intercropping did not affect N2O emissions. • N2O emission factors were higher than 1% for all treatments in dry season. • High yield scaled N2O emissions indicate that productivity is too low. The effort to increase the sustainable supply of food and fibre is challenged by the potential for increased greenhouse gas (GHG) emissions from farming systems with intensified production systems. This study aimed at quantifying soil N2O emissions from smallholder organic and conventional cotton production practices in a semi-arid area, Meatu, Northern Tanzania. Field experiments were conducted to quantify N2O emissions under (i) current practices with organic (3 Mg ha−1 farmyard manure (FYM)) and conventional (30 kg mineral N ha−1) cultivation; (ii) a high input practice with organic (5 Mg ha−1 FYM) and conventional (60 kg mineral N ha−1) cultivation; and (iii) an integrated practice with organic (3 Mg FYM + legume intercropping) and conventional (30 kg N + 3 Mg ha−1 FYM) cultivation. In both organic and conventional farming, control treatments with no fertilizer application were included. The study was performed over two growing seasons, where season 1 was rather wet and season 2 was rather dry. Static chambers were used for in-situ measurement of N2O emission from soil. The current organic and conventional cotton farming practices did not differ (P > 0.05) in cumulative area-scaled and yield-scaled N2O emissions. High input conventional cotton showed higher area scaled N2O emissions than organic cotton during the wetter season, but not during the drier season. The inorganic fertilizer + FYM combination did not differ (P > 0.05) in area- and yield-scaled N2O emissions from conventional practice. Intercropping cotton and legumes did not affect (P > 0.05) N2O emission compared to 3 Mg FYM ha−1. The emission factors for both conventional and organic systems were generally above 1% in the dry season 2, but below 1% in the wetter season 1. The use of organic and inorganic fertilizers at rates up to 60 kg N ha−1, FYM-inorganic fertilizer combination, and cotton-legume intercropping increased yields, while N2O emissions stayed low, in particular with use of mineral fertilizers.
[en] Over the past several decades, it has been shown that oxynitrides have several significant advantages over pure SiO2 for use as gate insulators in MOS devices. Oxynitrides have been grown by oxidation in N2O in a standard thermal oxidation furnace. Two N2O processes have been studied: oxidation in N2O only, and two-step oxidation with initial oxidation in O2 followed by oxidation/nitridation in N2O. Results are presented for radiation damage at 80 and 295K, hole trapping, interface trap creation, electron spin resonance, and hole de-trapping using thermally-stimulated current analysis. N2O oxynitrides do not appear to have the well-known drawbacks of NH3-annealed oxynitrides. Creation of interface traps during irradiation is reduced in the N2O oxynitrides, with the degree of improvement depending on the fabrication process
[en] The form and reproducibility of pantographic tracings under the influence of relaxant drugs and in patients with muscle dysfunction and TMJ disorders, tend to emphasize the dominance of the neuromuscular factors. The purpose of this study was to demonstrate the effect of nitrous oxide induced psychosedation, on the reproducibility of pantographic tracings of border movements of the mandible. This study included four male subjects (with no signs and symptoms of muscular dysfunction and temporomandibular joint problems). Operator guided border tracings were recorded using the Denar pantograph. Three sets of tracings were recorded: (1) three tracings prior to sedation (Tracing I); (2) one tracing prior to sedation and two after sedation (Tracing II); (3) three tracings after psychosedation (Tracing III). The coincidence of tracings I, II, and 111 were statistically analyzed applying the chi-square (X2) analysis. There was a significant difference in the coincidence of tracings between Tracings 1 and II (X2 = 14.892). There was no significant difference in the coincidence of tracings between Tracings I and III (X2 = 1.338). This suggests that nitrous oxide psychosedation produces a centrally induced relaxation of the musculature, by possibly eliminating the extraneous anxiety producing factors. (author)
[en] Being a potent greenhouse gas, N2O emitted by the terrestrial biosphere during abrupt climate change events could have amplified externally forced warming. To investigate this possibility, we tested the sensitivity of terrestrial N2O emissions to an abrupt warming event by applying the ARVE-DGVM in combination with a novel scheme for process-based simulation of terrestrial N2O and NOx emissions at the Gerzensee site in Switzerland. In this study, we aim to quantify the magnitude of change in emissions for the abrupt climate change event that occurred at the transition from Oldest Dryas to Boel-ling during the last deglaciation. Using high-resolution multiproxy records obtained from the Gerzensee that cover the Late Glacial, we apply a prescribed vegetation change derived from the pollen record and temperature and precipitation reconstructions derived from δ18O in lake sediments. Changes in soil temperature and moisture are simulated by the ARVE-DGVM using the reconstructed paleoclimate as a driver. Our results show a pronounced increase in mean annual N2O and NOx emissions for the transition (by factor 2.55 and 1.97, respectively), with highest amounts generally being emitted during summer. Our findings suggest that summertime emissions are limited by soil moisture, while temperature controls emissions during winter. For the time between 14670 and 14620 cal. years BP, our simulated N2O emissions show increase rates as high as 1% per year, indicating that local reactions of emissions to changing climate could have been considerably faster than the atmospheric concentration changes observed in polar ice.