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Abstract: Identification of the mechanisms contributing to nitrogen (N) fertilizer-induced changes in CO2 efflux from soil under agricultural crops has been extremely challenging because of difficulties in separating root and microbial contribution to total CO2 efflux. In this study we present the evidence that high costs of nitrate reduction result in a strong increase of root-derived respiration and the magnitude of an increase differs between the species with various contribution of shoots and roots to the nitrate reduction process. Fertilization of Lupinus albus and Zea mays with nitrate or ammonium and pulse labeling of plants in 14CO2 atmosphere allowed evaluation of the effect of N type on total and recently assimilated CO2 efflux from soil. Addition of nitrate to planted soil increased recently assimilated CO2 efflux by 168% in Lupinus albus (nitrate reduction site – in roots) and by 121% in Zea mays (nitrate reduction site both, in shoots and roots) in comparison with control. Ammonium-induced CO2 increase amounted for 82% in Lupinus albus and for 73% in Zea mays. Clear diurnal changes in CO2 efflux from planted soil at constant day/night temperature showed fast response of below-ground processes to photosynthesis. Both approaches for root-derived CO2 assessment: 14C pulse labeling and difference of CO2 from planted and unplanted soil showed similar results: the form of N supply and the location of the nitrate reduction site have a strong significant effect on the amount of root-derived CO2 respiration. [Copyright &y& Elsevier]

Abstract  The kelp bed of Gouqi Island lies in the east of the East China Sea, in the Shengsi Archipelago. It is a key component of the island-reef ecosystem. This study evaluated kelp beds on intertidal and subtidal zones from 2004 to 2006. We evaluated seasonal variations in the community structure of macroalgae, and their relationship with water temperature, nitrogen and phytoplankton. The Gouqi Island kelp bed consists mainly of species of Sargassum. Sargassum horneri was the dominant species in subtidal zones, representing 90% of the total biomass. The dominant species in intertidal zones were S. fusiforme, S. horneri, S. thunbergii and Undaria pinnatifida. Fifty-four phytoplankton species were found in the Gouqi Island kelp bed, of which 51 species were found inside the kelp beds, 43 species outside the kelp beds, and 40 species were present both inside and outside the kelp beds. Diatoms were dominant both inside and outside the kelp beds. Except in winter, Skeletonema costatum was dominant, and its abundance in autumn was over 98% of the total abundance. Water temperature was found to be the primary factor influencing the growth of S. horneri in the Gouqi Island kelp bed. S. horneri grew slowly from November to March, and rapidly from March to June. The upper temperature limit for growth of S. horneri was about 18°C. Higher water temperatures can result in a decline in the kelp bed. Nitrogen seemed to be a limiting factor for macroalgal growth. This was particularly true for S. horneri and phytoplankton. Since nitrate is the primary nutrient for S. horneri, its absorption by S. horneri resulted in seasonal changes of nitrate in the ecosystem. [ABSTRACT FROM AUTHOR]

Abstract: Negative gate bias is used in some applications for faster switching off the n-channel MOS devices. It is shown in this study that NBT stress-related instability in commercial n-channel power VDMOSFETs could be actually more serious than in corresponding p-channel devices. NBT stress is found to create equal V T shifts in both device types, whereas the subsequent positive bias annealing results in more serious overall V T instability in n-channel devices. The changes in the densities of stress-induced interface traps in two device types are equal as well, but significant amounts of NBT stress-induced border traps are only found in n-channel devices. All the results are discussed in terms of hydrogen reaction and diffusion model. [Copyright &y& Elsevier]

The thermal and light-induced spin transitions in [FexZn1−x(phen)2(NCS)2] (phen = 1,10-phenantholine) have been investigated by magnetic susceptibility, photomagnetism and diffuse reflectivity measurements. These complexes display a thermal spin transition and undergo the light-induced excited spin state trapping (LIESST) effect at low temperatures. For each compound, the thermal spin transition temperature, T1/2, and the relaxation temperature of the photo-induced high-spin state, T(LIESST), have been systematically determined. It appears that T1/2 decreases with the metal dilution while T(LIESST) remains unchanged. This behaviour is discussed on the basis of the kinetic study governing the photo-induced back conversion. [ABSTRACT FROM AUTHOR]

The article examines the impact of different averaging algorithms on daily maximum and minimum temperature. The authors found out that some surface climate networks produced a systematic warming or cooling bias in daily maximum or minimum temperature observation which led to resulting biases making the diurnal temperature range more biased in extreme climate studies, in comparison to the longest recorded and standard liquid-in-glass maximum and minimum thermometers. They recommend providing an accurate description of daily maximum and minimum temperatures to prevent the uncertainties in the observed climatology.